CN113495795A - Inter-process communication method and related equipment - Google Patents

Abstract

The present application provides an inter-process communication method and related equipment. The method includes: a first process creates a first shared memory between a second process and a third process; the second process writes first data into the first process mapping area, and maps the first data from the first mapping area to the first shared memory according to the first mapping relationship, and the third process maps the first data to the first shared memory according to the second mapping relationship A piece of data is mapped from the first shared memory to the second mapping area, so as to realize one-way communication from the second process to the third process. The above method can not only improve the security and reliability of the inter-process communication, but also can effectively improve the performance of the inter-process communication.

Description

An inter-process communication method and related equipment

technical field

The present application relates to the field of communication technologies, and in particular, to an inter process communication (inter process communications, IPC) method and related devices.

Background technique

IPC is a communication method for sharing messages between a process and another process, and is mainly used for message passing between different processes in a computer system. Among them, a process is the smallest unit of computer resource allocation. Each process has its own virtual address space and is isolated from the virtual address space of other processes. That is to say, a process can only access its own virtual address space and cannot access it. The virtual address space of other processes. In order to enable different processes to access each other and coordinate their work, the operating system provides a variety of IPC mechanisms.

However, the existing IPC mechanism has problems such as low performance or low security.

SUMMARY OF THE INVENTION

The embodiments of the present application disclose an inter-process communication method and related devices, which can not only improve the security and reliability of the inter-process communication, but also effectively improve the performance of the inter-process communication.

In a first aspect, the present application provides an inter-process communication method, the method comprising:

The first process creates the first shared memory between the second process and the third process, wherein the first process, the second process and the third process run in the user space, and the first process The first shared memory has read and write permissions, the second process has read and write permissions to the first shared memory, the third process has read-only permissions to the first shared memory, the second process and The third processes are all registered in the first process, the first mapping area and the first shared memory have a first mapping relationship, and the second mapping area and the first shared memory have a second mapping relationship. A mapping relationship, the first mapping area is an area in the virtual address space of the second process that establishes a mapping relationship with the first shared memory, and the second mapping area is in the virtual address space of the third process. Describe the area where the first shared memory establishes a mapping relationship;

The second process writes the first data into the first mapping area, and maps the first data from the first mapping area to the first shared memory according to the first mapping relationship, and the The third process maps the first data from the first shared memory to the second mapping area according to the second mapping relationship, thereby implementing one-way communication from the second process to the third process .

In the inter-process communication method provided by the present application, the first shared memory between the second process and the third process is created by the first process, the second process writes the first data into the first mapping area, and according to the first mapping relationship The first data is mapped from the first mapping area to the first shared memory, and the third process maps the first data from the first shared memory to the second mapping area according to the second mapping relationship, thereby realizing the transfer from the second process to the third process. One-way communication. Wherein, the process of transmitting the first data from the second process to the third process is realized by mapping the first mapping relationship and the second mapping relationship, and it can be realized without the system calling the kernel into the kernel space, without data copying and system overhead. Small, high communication efficiency. Moreover, when the inter-process communication method provided by the present application is applied to embedded devices with various operating systems, since the kernel state is not introduced in the one-way communication process from the second process to the third process, there is no need to consider the single board and the operating system. The problem of adaptation, the operation is simple, and the portability is strong. Meanwhile, in addition to the first process, only the second process has the read and write authority of the first shared memory, which can prevent multiple processes from simultaneously writing to the first shared memory, resulting in confusion of data in the first shared memory. In addition, the second process and the third process are both processes registered in the first process, the first process can verify the identities of the second process and the third process, and only has the read and write permissions of the first shared memory or Only processes with read-only permissions can access the first shared memory, which can prevent malicious programs from tampering with or destroy data in the first shared memory, and can effectively improve the security and reliability of inter-process communication.

In a specific implementation manner, after the first process creates the first shared memory between the second process and the third process, the method further includes:

The first process configures the second process to have read and write permissions to the first shared memory, and configures the third process to have read-only permissions to the first shared memory.

In the above solution, the first process configures the second process to have the read-write permission of the first shared memory, and configures the third process to have the read-only permission of the first shared memory to ensure that the process has the read-write permission of the first shared memory. Only the first shared memory can be written to, and the process with the read-only permission of the first shared memory can only read the first shared memory, which can prevent malicious programs from reading and writing the first shared memory and ensure the first shared memory. The data in memory will not be modified or even destroyed by malicious programs.

In a specific implementation manner, the first process configures the second process to have read and write permissions of the first shared memory, and configures the third process to have read-only permissions of the first shared memory ,include:

The first process configures the second process to have read and write permissions of the first shared memory by using an access control list ACL, and configures the third process to have read-only permissions of the first shared memory.

In a specific implementation manner, before the second process writes the first data into the first mapping area, the method further includes:

The second process allocates a first heap memory, and the first heap memory is used to store control information of the second process;

The second process acquires the control information of the second process from the first heap memory, so that the second process writes the first data into the first process according to the control information of the second process. a mapping area;

Before the third process maps the first data from the first shared memory to the second mapping area, the method further includes:

The third process allocates a second heap memory, and the second heap memory is used to store control information of the third process;

The third process obtains the control information of the third process from the second heap memory, so that the third process converts the first data from the first data from the first process according to the control information of the third process. The shared memory is mapped to the second mapping area.

In the above scheme, by storing the control information of the second process in the first heap memory (the heap memory of the first process), and storing the control information of the third process in the second heap memory (the heap memory of the third process), When the second process communicates with the third process, the second process and the third process can directly obtain their own control information from their own heap memory for communication, and the efficiency of inter-process communication is high. At the same time, by storing the control information of the second process in the first heap memory and storing the control information of the third process in the second heap memory, the control information of the second process and the control information of the third process can also be stored separately. , which is beneficial for the second process and the third process to be independent and non-interfering with each other during operation. When one of the second process and the third process fails, the failure will not spread to the other process.

In a specific implementation manner, the first heap memory and the first mapping area are different memories, the first mapping area is used to store the shared memory information of the second process, and the second The heap memory and the second mapping area are different memory, and the second mapping area is used to store the shared memory information of the third process.

In the above solution, the control information of the second process is stored in the first heap memory, the shared memory information of the second process is stored in the first mapping area, and the first heap memory and the first mapping area are different memories, which can realize the first The separate storage of the control information of the second process and the shared memory information of the second process is beneficial to ensure the safety of the shared memory information of the second process. Similarly, the control information of the third process is stored in the second heap memory, and the shared memory information of the third process is stored in the second mapping area, and the second heap memory and the second mapping area are different memories, so that the third The separate storage of the control information of the process and the shared memory information of the third process is beneficial to ensure the safety of the shared memory information of the third process.

In a specific implementation manner, before the second process writes the first data into the first mapping area, the method further includes:

The first process allocates a third heap memory, and the third heap memory is used to store control information of the second process;

The first process receives a first information acquisition request sent by the second process, wherein the first information acquisition request is used to request to acquire control information of the second process from the third heap memory;

The first process sends the control information of the second process to the second process according to the first request for obtaining information, so that the second process sends the control information of the second process to the second process according to the control information of the second process. A data is written into the first mapping area;

Before the third process maps the first data from the first shared memory to the second mapping area, the method further includes:

The third process allocates a second heap memory, and the second heap memory is used to store control information of the third process;

The third process obtains the control information of the third process from the second heap memory, so that the third process converts the first data from the first data from the first process according to the control information of the third process. The shared memory is mapped to the second mapping area.

In the above solution, by storing the control information of the second process in the third heap memory (the heap memory of the first process), and storing the control information of the third process in the heap memory of the third process, between the second process and the third process When processes communicate, the second process needs to first send a request for obtaining control information to the first process, and then obtain the control information of the second process returned by the first process, and the third process can obtain its own control information from its own heap memory. , it can be seen that the communication efficiency of the second process is lower than that of the third process. That is to say, the method of storing process control information in the process's own heap memory is suitable for processes with high performance requirements; the method of storing process control information in the heap memory of the first process is suitable for lower performance requirements. process. It can be seen that the above method is not only suitable for processes with high communication performance requirements, but also suitable for processes with low communication performance requirements, and has high flexibility. At the same time, by storing the control information of the second process in the heap memory of the first process, and storing the control information of the third process in the heap memory of the third process, the control information of the second process and the control of the third process can also be realized. The separate storage of information is beneficial for the second process and the third process to be independent of each other and not interfere with each other during operation. When one of the second process and the third process fails, the failure will not spread to the other process.

In a specific implementation manner, the third heap memory and the first mapping area are different memory, the first mapping area is used to store the shared memory information of the second process, the second The heap memory and the second mapping area are different memory, and the second mapping area is used to store the shared memory information of the third process.

In the above scheme, the control information of the second process is stored in the third heap memory (, the shared information of the second process is stored in the first mapping area, and the control information of the second process and the shared memory information of the second process can be realized. Store separately, help to guarantee the safety of the shared memory information of the second process.Meanwhile, the control information of the third process is stored in the second heap memory, and the shared memory information of the third process is stored in the second mapping area, which can realize the first The separate storage of the control information of the three processes and the shared memory information of the third process is beneficial to ensure the safety of the shared memory information of the third process.

In a specific implementation manner, before the second process writes the first data into the first mapping area, the method further includes:

The second process allocates a first heap memory, and the first heap memory is used to store control information of the second process;

The second process acquires the control information of the second process from the first heap memory, so that the second process writes the first data into the first process according to the control information of the second process. a mapping area;

Before the third process maps the first data from the first shared memory to the second mapping area, the method further includes:

The first process allocates a third heap memory, and the third heap memory is used to store control information of the third process;

The first process receives a second information acquisition request sent by the third process, where the second information acquisition request is used to request to acquire control information of the third process from the third heap memory;

The first process sends the control information of the third process to the third process according to the second request for obtaining information, so that the third process sends the control information of the third process to the third process according to the control information of the third process. A data is mapped from the first shared memory to the second mapped area.

In a specific implementation manner, the first heap memory and the first mapping area are different memory, the first mapping area is used to store the shared memory information of the second process, the third The heap memory and the second mapping area are different memory, and the second mapping area is used to store the shared memory information of the third process.

In the above solution, the control information of the second process is stored in the first heap memory, and the shared information of the second process is stored in the first mapping area, so that the control information of the second process and the shared memory information of the second process can be separated. The storage is beneficial to ensure the safety of the shared memory information of the second process. At the same time, the control information of the third process is stored in the third heap memory, and the shared memory information of the third process is stored in the second mapping area, so that the control information of the third process and the shared memory information of the third process can be stored separately. , which is beneficial to ensure the security of the shared memory information of the third process.

In a specific implementation, the first process includes a detection thread, and the method further includes:

The detection thread detects whether the second process or the third process is reset;

In the case of detecting that the second process or the third process is reset, the detection thread notifies the second process and the third process that have not been reset to terminate communication, and releases the third process a shared memory.

In the above solution, the first process can also detect whether the second process or the third process is reset, and in the case of detecting that the second process or the third process is reset, the communication between the second process and the third process can be terminated in time. communication, and release the resources occupied by the first shared memory, which is conducive to the timely recovery of resources.

In a specific implementation manner, the first process includes a restoration shared memory thread, and the restoration shared memory thread is a thread with the highest running level among the threads included in the first process, and the method further includes:

When the first process is restarted, the restoring shared memory thread restores the first shared memory.

In the above solution, when the first process is restarted, the restoring shared memory thread with the highest running level in the first process can quickly restore the first shared memory, thereby further improving the reliability of inter-process communication.

In a specific implementation manner, the first shared memory includes a destroyer queue, and the second process maps the first data from the first mapping area to the first shared memory, including:

the second process maps the first data from the first mapping area to the destroyer queue;

The third process maps the first data from the first shared memory to the second mapping area, including:

The third process maps the first data from the spoiler queue to the second mapping area.

In the above solution, the first shared memory includes a destroyer queue, which supports repeated reading and writing of the first shared memory, which can effectively improve the throughput of inter-process information and further improve the performance of inter-process communication.

In a specific implementation, the method further includes:

The first process creates a second shared memory between the second process and the third process, wherein the first process has read and write permissions to the second shared memory, and the third process has read and write permissions to the second shared memory. The second shared memory has read and write permissions, the second process has read-only permissions to the second shared memory, the third mapping area and the second shared memory have a third mapping relationship, and the fourth mapping There is a fourth mapping relationship between the area and the second shared memory, the third mapping area is an area in the virtual address space of the third process that establishes a mapping relationship with the second shared memory, and the fourth mapping The area is an area in the virtual address space of the second process that establishes a mapping relationship with the second shared memory;

The third process writes the second data into the third mapping area, and maps the second data from the third mapping area to the second shared memory according to the third mapping relationship , the second process maps the second data from the second shared memory to the fourth mapping area according to the fourth mapping relationship, so as to realize the transfer from the third process to the second process One-way communication.

In the above solution, the second shared memory between the second process and the third process is created by the first process, the third process writes the second data into the third mapping area, and according to the third mapping relationship The third mapping area is mapped to the second shared memory, and the third process maps the second data from the second shared memory to the fourth mapping area according to the fourth mapping relationship. Thereby, one-way communication from the third process to the second process is realized. Wherein, the process of transmitting the second data from the third process to the second process is realized by mapping the third mapping relationship and the fourth mapping relationship, which can be realized without the system calling the kernel into the kernel space, without data copying and system overhead. Small, high communication efficiency. Moreover, when applied to embedded devices with various operating systems, since the kernel state is not introduced in the one-way communication process from the third process to the second process, there is no need to consider the problem of adapting the board and the operating system, and the operation is simple. Portable. At the same time, in addition to the first process, only the third process has read and write permissions to the second shared memory, which can prevent multiple processes from simultaneously writing to the second shared memory, or malicious programs tampering or destroying data in the second shared memory , causing data confusion in the second shared memory. In addition, both the second process and the third process are processes registered in the first process, the first process can verify the identities of the second process and the third process, and only has the read and write permissions of the second shared memory or Only processes with read-only permissions can access the second shared memory, which can effectively improve the security and reliability of inter-process communication.

In a second aspect, the present application provides an inter-process communication device, the device comprising:

The creation module is used to create the first shared memory between the second process and the third process through the first process, wherein the first process, the second process and the third process run in the user space, so the first process has read and write permissions to the first shared memory, the second process has read and write permissions to the first shared memory, and the third process has read-only permissions to the first shared memory, Both the second process and the third process are registered in the first process, there is a first mapping relationship between the first mapping area and the first shared memory, and the second mapping area is shared with the first There is a second mapping relationship between memories, the first mapping area is an area in the virtual address space of the second process that establishes a mapping relationship with the first shared memory, and the second mapping area is the third process. an area in the virtual address space that establishes a mapping relationship with the first shared memory;

a communication module, configured to write first data into the first mapping area through the second process, and map the first data from the first mapping area to the first mapping area according to the first mapping relationship a shared memory, and the third process maps the first data from the first shared memory to the second mapping area according to the second mapping relationship, so as to realize the second process to all One-way communication of the third process.

In a specific implementation manner, the creation module is further used for:

The creation module configures, through the first process, the second process to have read and write permissions of the first shared memory, and configures the third process to have read-only permissions of the first shared memory.

In a specific implementation manner, the creation module is specifically used for:

The creation module configures the second process to have read and write permissions of the first shared memory through the access control list ACL by the first process, and configures the third process to have read-only access to the first shared memory permissions.

In a specific implementation manner, before the second process writes the first data into the first mapping area, the apparatus further includes: an allocation module and an acquisition module;

the allocation module, configured to allocate a first heap memory through the second process, where the first heap memory is used to store control information of the second process;

The acquiring module is configured to acquire the control information of the second process from the first heap memory through the second process, so that the second process can retrieve the control information of the second process according to the control information of the second process. first data is written into the first mapping area;

Before the third process maps the first data from the first shared memory to the second mapping area, the allocation module is further configured to allocate the second heap memory by the third process, so The second heap memory is used to store the control information of the third process;

The obtaining module is further configured to obtain, through the third process, the control information of the third process from the second heap memory, so that the third process can obtain the control information of the third process according to the control information of the third process. The first data is mapped from the first shared memory to the second mapping area.

In a specific implementation manner, the first heap memory and the first mapping area are different memories, the first mapping area is used to store the shared memory information of the second process, and the second The heap memory and the second mapping area are different memory, and the second mapping area is used to store the shared memory information of the third process.

In a specific implementation manner, before the second process writes the first data into the first mapping area, the apparatus further includes a sending module;

the allocation module, configured to allocate a third heap memory through the first process, where the third heap memory is used to store control information of the second process;

The obtaining module is configured to receive, through the first process, a first obtaining information request sent by the second process, wherein the first obtaining information request is used to request to obtain the information from the third heap memory. control information of the second process;

The sending module is configured to send, through the first process, the control information of the second process to the second process according to the first information acquisition request, so that the second process The control information of the process writes the first data into the first mapping area;

Before the third process maps the first data from the first shared memory to the second mapping area, the allocation module is further configured to allocate the second heap memory by the third process, so The second heap memory is used to store the control information of the third process;

The obtaining module is further configured to obtain, through the third process, the control information of the third process from the second heap memory, so that the third process can obtain the control information of the third process according to the control information of the third process. The first data is mapped from the first shared memory to the second mapping area.

In a specific implementation manner, the third heap memory and the first mapping area are different memory, the first mapping area is used to store the shared memory information of the second process, the second The heap memory and the second mapping area are different memory, and the second mapping area is used to store the shared memory information of the third process.

In a specific implementation manner, before the second process writes the first data into the first mapping area,

the allocation module, configured to allocate a first heap memory through the second process, where the first heap memory is used to store control information of the second process;

The acquiring module is configured to acquire the control information of the second process from the first heap memory through the second process, so that the second process can retrieve the control information of the second process according to the control information of the second process. first data is written into the first mapping area;

Before the third process maps the first data from the first shared memory to the second mapping area, the apparatus further includes a receiving module;

the allocation module, configured to allocate a third heap memory through the first process, where the third heap memory is used to store control information of the third process;

The receiving module is configured to receive, through the first process, a second request for obtaining information sent by the third process, wherein the second request for obtaining information is used to request to obtain the information from the third heap memory. Control information of the third process;

The sending module is configured to send, through the first process, the control information of the third process to the third process according to the second request for obtaining information, so that the third process The control information of the process maps the first data from the first shared memory to the second mapping area.

In a specific implementation manner, the first heap memory and the first mapping area are different memory, the first mapping area is used to store the shared memory information of the second process, the third The heap memory and the second mapping area are different memory, and the second mapping area is used to store the shared memory information of the third process.

In a specific implementation manner, the first process includes a detection thread, and the apparatus further includes a detection module, and the detection module is specifically configured to:

The detection module detects, through the detection thread, whether the second process or the third process is reset;

When the detection module detects that the second process or the third process is reset, the detection thread notifies the second process and the third process that no reset occurs to terminate the communication, and release the first shared memory.

In a specific implementation manner, the first process includes a restoration shared memory thread, and the restoration shared memory thread is a thread with the highest running level among the threads included in the first process, and the apparatus further includes a restoration module, The recovery module is specifically used for:

When the first process is restarted, the restoring module restores the first shared memory through the restoring shared memory thread.

In a specific implementation manner, the first shared memory includes a destroyer queue, and the communication module is specifically configured to:

The communication module maps the first data from the first mapping area to the destroyer queue through the second process;

The communication module maps the first data from the spoiler queue to the second mapping area through the third process.

In a specific implementation manner, the creating module is further configured to create a second shared memory between the second process and the third process by using the first process, wherein the first process The second shared memory has read and write permissions, the third process has read and write permissions to the second shared memory, the second process has read-only permissions to the second shared memory, and the third mapping area There is a third mapping relationship with the second shared memory, a fourth mapping relationship is between the fourth mapping area and the second shared memory, and the third mapping area is in the virtual address space of the third process an area that establishes a mapping relationship with the second shared memory, and the fourth mapping area is an area that establishes a mapping relationship with the second shared memory in the virtual address space of the second process;

The communication module is further configured to write the second data into the third mapping area through the third process, and according to the third mapping relationship, write the second data from the third mapping The area is mapped to the second shared memory, and the second process maps the second data from the second shared memory to the fourth mapping area according to the fourth mapping relationship, so as to realize the first One-way communication of the three processes to the second process.

In a third aspect, the present application provides an inter-process communication device, the device includes: a processor, a communication interface, and a memory; the memory is used for storing instructions, the processor is used for executing the instructions, and the communication interface is used for for receiving or sending data; wherein, when the processor executes the instruction, the method described in the first aspect or any specific implementation manner of the first aspect is performed.

In a fourth aspect, the present application provides a computer storage medium, where the computer storage medium stores a computer program for inter-process communication, and when the computer program is executed by a processor, implements the first aspect or any specific implementation of the first aspect. The method described in the implementation.

In a fifth aspect, the present application provides a computer program product, characterized in that, when the computer program product is read and executed by a computer, the method described in the first aspect or any specific implementation manner of the first aspect is implemented. .

Description of drawings

The accompanying drawings used in the embodiments of the present application will be introduced below.

1 is a schematic diagram of an application scenario of an inter-process communication method provided by an embodiment of the present application;

2 is a schematic diagram of a data transmission process provided by an embodiment of the present application;

3 is a schematic diagram of an interprocess communication system based on a binding agent mechanism provided by an embodiment of the present application;

4 is a schematic flowchart of an inter-process communication method provided by an embodiment of the present application;

5 is a schematic diagram of a destroyer queue provided by an embodiment of the present application;

6 is a schematic diagram of a process virtual address space provided by an embodiment of the present application;

7 is a schematic flowchart of an inter-process communication method provided by an embodiment of the present application;

FIG. 8 is an interactive schematic diagram of an inter-process communication method provided by an embodiment of the present application;

FIG. 9 is a schematic structural diagram of an inter-process communication apparatus provided by an embodiment of the present application;

FIG. 10 is a schematic structural diagram of another inter-process communication apparatus provided by an embodiment of the present application.

Detailed ways

The embodiments of the present application will be described below with reference to the accompanying drawings in the embodiments of the present application.

Before introducing the methods in the embodiments of the present application, in order to facilitate the understanding of the embodiments of the present application by those skilled in the art, related concepts involved in the embodiments of the present application are first introduced.

Process isolation is a technology designed to protect processes in an operating system from interfering with each other. This technique is to prevent process A from modifying the data in process B, so as to prevent process A from affecting the operation of process B, or even process A will destroy the operation of process B. Processes are isolated through virtual address spaces. Specifically, the virtual address space of process A is different from the virtual address space of process B, so that process A can be prevented from modifying data in process B.

Virtual Address Space: Virtual address space does not actually exist in the computer. Each process is allocated its own virtual address space, and can only access the virtual address space it is allocated for. In theory, the virtual address space is limited by the size of physical memory. For example, if the physical memory is 4GB, the address range of the virtual address space should be 0x00000000~0xFFFFFFFF. Each process has its own independent virtual address space, so that each process can access its own virtual address space, which achieves effective process isolation.

Physical address space: The physical address space is an entity that exists in a computer and maintains unique independence in each computer. It can also be called physical memory. For example, on a 32-bit machine, the size of physical memory can theoretically reach 4GB, but if 512MB of memory is actually installed, the real effective part of its physical address space is only 512MB, and other parts are invalid.

There is a mapping between the virtual address space and the physical address space. The mapping is done by a memory management unit (MMU), and a process can indirectly operate the physical address space by operating its own virtual address space.

User space (user space) is the space where user programs run, and kernel space (kernel space) is the space where the system kernel runs. Today's operating systems use virtual memory. For a 32-bit system, its virtual address space is 2 to the 32nd power, that is, 4GB. The core of the operating system is the kernel, which is independent of ordinary applications and can access the protected virtual address space as well as the underlying hardware devices. In order to protect the user process from directly operating the kernel and ensure the security of the kernel, the operating system logically divides the virtual address space into user space and kernel space. For the Linux operating system, the highest 1GB bytes are used by the kernel, which is called kernel space, and the lower 3GB bytes are used by each process, which is called user space. That is to say, in the 4GB virtual address space of each process, the highest 1GB is the same, that is, the kernel space. Only the remaining 3GB is used by the process itself. In other words, kernel space is shared by all processes.

User mode: When the process runs in user space, it is in user mode. At this time, the processor runs in the Ring3 user code with the lowest privilege level, and the Ring3 state cannot access the address space of Ring0, including code and data.

Kernel state: When the process runs in the kernel space, it is in the kernel state. The process can execute system calls and fall into the kernel space to run. At this time, the processor is executed in the kernel code of Ring0 level with the highest privilege level.

Although the operating system logically divides the user space and the kernel space, it is inevitable that some processes running in the user space need to access the resources of the kernel space, such as file operations or network access, etc., which need to be implemented with the help of system calls. operate. System calls are the only way for user space processes to access kernel space, which ensures that all operations are carried out under the control of the kernel, avoids unauthorized access to kernel space by user space processes, and improves system security and stability. .

In user mode, a process can only access memory in a limited manner, and is not allowed to access peripheral devices, such as hard disks, network cards, etc., the ability to occupy the central processing unit (CPU) is deprived, and CPU resources can be used by other processes. Obtain.

In kernel mode, the CPU can access all data in memory, including peripheral devices, and the CPU can also switch itself from one process to another.

The application scenario of IPC can be for one process to send its data to another process, or for one process to send a message to another process to notify another process that some event has occurred, or for one of the two processes. Shared data is modified, another process should see it immediately, etc.

Here, an application scenario of the inter-process communication method provided by the embodiment of the present application is introduced by taking one process sending its data to another process as an example.

As shown in Figure 1, both process A and process B are located in user space, and process A and process B are two different processes. Process A includes data A. When process B also wants to use data A in process A, Since process A and process B are different processes, there is process isolation, so process B cannot directly use data A in process A. If process B can use data A in process A, a special communication mechanism must be adopted, namely ipc.

It can be understood that when process A provides data A to process B, process A is the server process in the client/server (C/S) mode, and process B is the client in the C/S mode. process. Similarly, if process B provides its own data B to process A, process B is the server process in the C/S mode, and process A is the client process in the C/S mode. In the C/S mode, the process running on the client is the client process, and the process running on the server is the server process.

At present, in order to enable different processes to access each other and coordinate their work, the operating system provides a variety of IPC mechanisms, such as sockets, pipes, message queues, shared memory, and binders.

Among them, the socket used for inter-process communication is an abstraction layer. Process A and process B can send or receive data through the socket. Process A and process B can open, read, write, and close the socket as if they were files. A socket can be regarded as an endpoint in the respective communication connection when two network processes communicate. During communication, process A writes the data A to be transmitted into the socket of the host where process A is located, and the socket sends data A to the socket of the host where process B is located through the transmission medium of the network interface card, so that data A can be transmitted to process B. , so as to realize the communication between process A and process B. However, in the process of using sockets to communicate, the process needs to execute system calls and get trapped in the kernel space to perform data transmission, and the transmission efficiency is low. Therefore, sockets are mainly used for inter-process communication on different hosts across the network and low-speed communication between processes on the same host.

A pipe used for interprocess communication is the oldest form of Yonex (unix) IPC, a special in-memory file. Pipes are divided into named pipes and anonymous pipes. Named pipes allow communication between two unrelated processes. Anonymous pipes can only communicate in one direction and can only be used between related processes. They are often used in parent and child processes. See Figure 2 and related descriptions for problems with the pipeline.

A message queue used for interprocess communication is a linked list of messages, stored in the kernel and identified by a message queue identifier. By using message queues, processes can read messages sequentially, or prioritize messages. See also Figure 2 and related descriptions for the problems with message queues.

As shown in Figure 2, the pipelines and message queues used for inter-process communication, during data transmission, usually process A opens up a memory cache area in its own virtual address space, and process A stores data A in the memory cache. Then, process A falls into the kernel space through a system call, and the kernel calls the copy from user function to copy data A from the memory buffer area of process A to the kernel buffer area opened by the kernel. After the kernel copies the data A to the kernel buffer, the kernel calls the copy to user function from the kernel mode to copy the data A from the kernel buffer to the memory buffer opened by the process B. In this way, process A and process B complete a data A transmission, that is, process A and process B complete an inter-process communication.

It can be seen that the pipes and message queues used for inter-process communication, when performing data transmission, process A also needs to execute a system call to fall into the kernel space to perform data transmission, and the kernel needs to copy data A from the memory buffer area of process A. To the kernel buffer area, and then copy from the kernel buffer area to the memory buffer area of process B, this process requires two data copies, and the efficiency of data transmission is low.

Shared memory used for inter-process communication is the same physical memory that process A and process B are allowed to access. Process A and process B can map the same piece of physical memory into their own virtual address space, and then process A and process B can access the physical memory.

When process A transmits data A to process B through shared memory, process A writes data A into its own virtual address space, and through the mapping relationship between process A's virtual address space and shared memory, the data in process A's virtual address space A is mapped to the shared memory, and then, through the mapping relationship between the virtual address space of process B and the shared memory, the data A in the shared memory is mapped to the virtual address space of process B. That is to say, when process A writes data A in its own virtual address space, data A will be immediately mapped to the virtual address space of process B that can access the same shared memory, so that it can be read by process B in time.

It can be seen that the shared memory used for inter-process communication can realize data transmission only through mapping without data copying, so efficient communication between processes can be achieved, which is a very effective way to share and transfer data between processes . However, shared memory control is complicated. For example, when process A writes to the shared memory, there is no automatic mechanism to prevent process B from reading the shared memory. At the same time, if multiple processes simultaneously write or read the shared memory , multiple processes compete for resources, which will cause the data in the shared memory to be chaotic. Therefore, in the prior art, it is usually necessary to use other mechanisms such as read-write locks or mutex locks to ensure that when process A writes to the shared memory, process B cannot read the shared memory, and to prevent multiple processes from simultaneously Resource contention caused by read or write operations to shared memory.

In addition, with the above mechanisms for inter-process communication, during data transmission, process A and process B cannot obtain each other's reliable user identification (user identification, UID) or process identification (process identification, PID), that is, Process A and process B cannot reliably verify the identity of each other. At the same time, the access points of the above communication mechanisms are all open, and a private communication channel cannot be established between process A and process B. A malicious program can establish a connection with another process by guessing the address of process A or process B. , stealing messages. It can be seen that the above mechanisms for inter-process communication still have the problem of low security.

Next, the currently popular binder mechanism for inter-process communication is introduced. The binder mechanism is an inter-process communication mechanism in the Android (android) operating system and is often used in android devices.

As shown in Figure 3, an IPC system based on the binder mechanism usually includes four parts: client, server, binder driver, and service management module. It can be seen that the service mode adopted by the binder mechanism is also the C/S mode. in,

Server process (such as process A): a process that provides services (such as data A) for use by client processes.

Client process (such as process B): The process that wants to use the service (such as data A) in the server process.

Binder driver: The client process can obtain a service in the server process through the binder driver, and then the client can call the service to obtain the result.

Service management module: If the server process wants to provide services for the client process, the server process needs to submit its own UID or PID for registration in the service management module, and register the services it can provide in the service management module. In order to let the service management module know which services the server process can provide to the client process, when the client process wants to use the services in the server process, it also needs to submit its own UID or PID for registration in the service management module. Then you can go to the service management module to get the service.

It can also be seen from Figure 3 that shared memory is used in the binder mechanism for inter-process communication, and the shared memory is implemented through memory mapping.

The process of data transmission through shared memory in the binder mechanism is:

Process A copies data A from the virtual address space of process A to the kernel buffer area by calling the copy from user function. Since there is a mapping between the kernel buffer area and the data receiving buffer area, the data A in the kernel buffer area can be directly mapped to The data receiving buffer area, since the data receiving buffer area is mapped to the virtual address space of process B, the data A in the data receiving buffer area is directly mapped to the virtual address space of process B, so that process A and process B complete the data once A's transmission, that is, process A and process B complete an inter-process communication. It can be seen that in this data transmission process, the kernel needs to execute a system call to copy data A from the virtual address space of process A to the kernel cache area, that is, in this data transmission process, a data copy is required.

In addition, it can be seen from Figure 3 that the client process, the server process and the service management module run in the user space, and the binder driver runs in the kernel space. The interaction between the client process, the server process and the service management module is a dotted line, which means that the client process, the server process and the service management module do not interact directly, but interact through the binder driver, that is to say, The interaction between the client process, the server process and the service management module needs to fall into the kernel space through system calls, and interact through the binder driver located in the kernel space.

From the above introduction to the binder mechanism for inter-process communication, when process A and process B communicate through the binder mechanism, both process A and process B need to be registered in the service management module, and then process A and process B are connected. It can be seen that the binder mechanism supports the verification of the identities of process A and process B, which can improve the security of inter-process communication. In addition, shared memory is introduced into the binder mechanism for inter-process communication, which improves the efficiency of inter-process communication. However, the binder mechanism used for inter-process communication also introduces the kernel state in the communication process. When data transmission is performed, a data copy is also required, which has an impact on the performance of the operating system and cannot meet some needs for zero-time data. Copies of interprocess communication scenarios. At the same time, the binder mechanism is an IPC mechanism in the android operating system, and is not applicable to terminal devices built on operating systems such as linux and windows.

In addition, for the above several other inter-process communication mechanisms except shared memory, when data transmission is performed between processes, the process needs to execute system calls and fall into the kernel space to perform data transmission. The kernel state is introduced. When several other inter-process communication mechanisms other than memory are applied to embedded devices with various operating systems, it is necessary to adapt the single board of the embedded device and the operating system, which is complicated in operation and low in portability. Moreover, if there is a problem in the kernel state, the new inter-process communication will be separated from the kernel state, resulting in confusion.

In order to solve the problems of low security and reliability in the above-mentioned inter-process communication mechanism, or low performance due to the introduction of kernel mode, the present application provides an inter-process communication method, which can not only improve the security and reliability of inter-process communication, but also can Effectively improve the performance of inter-process communication. The inter-process communication method provided by the embodiments of the present application is not only applicable to terminal devices constructed based on the android operating system, but also applicable to terminal devices constructed based on operating systems such as linux and windows, which are not specifically limited here.

The inter-process communication method provided by the embodiment of the present application is described in detail below.

Please refer to FIG. 4. FIG. 4 is a schematic flowchart of an inter-process communication method provided by an embodiment of the present application. As shown in FIG. 4, the method may include:

S101. The first process creates a first shared memory between the second process and the third process.

The first process, the second process and the third process run in user space, the first process has read and write permissions to the first shared memory, the second process has read and write permissions to the first shared memory, and the third process has read and write permissions to the first shared memory. The shared memory has read-only permission, and both the second process and the third process are registered in the first process.

Both the second process and the third process are registered in the first process, that is, before the first process creates the first shared memory between the second process and the third process, the second process and the third process need to be registered in the first process. Register in the first process. Here, the process of registering the second process and the third process in the first process is described.

Taking the registration of the second process in the first process as an example, specifically, the first process and the second process may establish a connection through a domain socket (domain socket) communication mechanism, and after the first process and the second process establish a connection , the first process registers for the second process. Among them, domain socket is an IPC mechanism developed on the framework of socket, which is used for inter-process communication of the same host.

More specifically, the first process can use the listen function in the domain socket communication mechanism to monitor whether a process sends a registration request to it. When the first process monitors that the second process sends a registration request to it, The first process may receive the registration request through the accept function in the domain socket mechanism, and establish a connection with the second process. After the first process establishes the connection with the second process, the first process may register the second process according to the registration request. The registration request sent by the second process to the first process may be sent to the first process through a connect (connect) function in the domain socket communication mechanism.

The registration request sent by the second process may include information such as the UID or PID of the second process, which is used by the first process to verify the identity of the second process, and can also be used by the first process according to the UID of the second process. Or information such as PID is registered for the second process.

It can be understood that the process of registering the third process in the first process is similar to the process of registering the second process in the first process. For specific implementation, reference may be made to the process of registering the second process in the first process described in the foregoing embodiment. The process will not be repeated here.

During the process of registering the second process by the first process, the first process may also create a first shared memory according to information such as the UID or PID of the second process included in the registration request, and the first shared memory is used to implement the second process One-way communication to other processes (such as a third process). Similarly, in the process of registering the third process by the first process, the first process can also create a second shared memory according to the information such as the UID or PID of the third process, and the second shared memory is used to enable the third process to communicate with other processes. One-way communication for a process (such as a second process).

In the embodiment of the present application, the first shared memory is created by the first process by creating a first shared file by the first process. The first shared file is a file that actually exists in the physical memory, and the physical address of the first shared memory is Same as the physical address of the first shared file. Similarly, the creation of the second shared memory by the first process is also achieved through the creation of the second shared file by the first process. The second shared file is also a file that actually exists in the physical memory. The physical address of the second shared memory is the same as the second shared memory. The physical addresses of the shared files are the same.

The first shared memory and the second shared memory may also have a shared memory identifier, the shared memory identifier is used to uniquely identify a shared memory, and the shared memory identifier can be named according to information such as the physical address of the shared memory or the UID or PID of the process. For example, the identifier of the first shared memory may be named according to information such as the UID or PID of the second process, and the identifier of the second shared memory may be named according to information such as the UID or PID of the third process. The first shared file and the second shared file may also have a shared file identifier. The shared file identifier is used to uniquely identify a shared file. The shared file identifier can be named according to the physical address of the shared file or the UID or PID of the process. For example, the identifier of the first shared file may be named according to information such as the UID or PID of the second process, and the identifier of the second shared file may be named according to information such as the UID or PID of the third process.

In a specific implementation, the first process may also save information such as the UID or PID of the second process, information such as the UID or PID of the third process, the first shared memory identifier, the second shared memory identifier, and the like. When the first process needs to manage the second process or the third process, the first process can manage the process according to information such as the UID or PID of the process, so as to meet the management requirements of the process; when the first process needs to manage the first shared memory Or when the second shared memory is used, the first process can find the corresponding shared memory for management according to the shared memory identifier, so as to meet the management requirements of the shared memory.

In the embodiment of the present application, after the first process completes the creation of the first shared memory, the first process acts as the creator of the first shared memory, that is, the owner, and the first process not only has the read and write permissions of the first shared memory, The first process also has the right to configure the first shared memory for other processes. For example, the first process may configure the second process to have read and write permissions of the first shared memory, and configure the third process to have read-only permissions of the first shared memory. Wherein, the process has the read and write authority of the first shared memory, which means that the process can perform read and write operations on the first shared memory. The process has the read-only permission of the first shared memory, which means that the process can only perform read operations on the first shared memory and cannot perform write operations.

It can be seen from the above embodiment that the first shared memory corresponds to the first shared file. Therefore, the first process can configure the second process to have the read and write permissions of the first shared file, so that the second process has the read and write permissions of the first shared memory. permission, and by configuring the third process to have the read-only permission of the first shared file, the third process has the read-only permission of the first shared memory.

Specifically, the first process may configure the second process to have read-write permission of the first shared memory, and configure the third process to have read-only permission of the first shared memory through an access control list (access control list, ACL). Among them, ACL is an access control list for files/directories. ACL allows any user (process) to set access rights to any file/directory, and it consists of a series of rules. Access permissions include three permissions: readable r (read), writable w (write), or executable x (execute). Readable r means that the actual content of the file can be read; writable w means that the actual content of the file can be edited, modified, added, and deleted, but the file cannot be deleted; executable x means that the file has permission to be executed by the system.

Specifically, the first process can set the second process and the third process as others of the first shared file through the set file ACL permission (setfacl) command in the ACL, and set the second process to have read and write permissions of the first shared file (rw-), set the third process to have the read-only permission (r--) of the first shared file. After the setting is completed, the first process can check whether the second process has the read and write permission (rw-) of the first shared file through the view file ACL permission (getfacl) command in the ACL, and whether the third process has the first shared file. Read-only permission (r--) for a shared file. The second process has the read and write authority of the first shared file, which means that the second process has the read and write authority of the first shared memory. The third process has the read-only permission of the first shared file, which means that the third process has the read-only permission of the first shared memory.

After the second process has the read and write permission of the first shared memory, if the second process wants to perform read and write operations on the first shared memory, the second process also needs to establish a mapping between its own virtual address space and the first shared memory relation. After the mapping relationship is established, the second process can perform read and write operations on the first shared memory. Similarly, after the third process has the read-only permission of the first shared memory, if the third process wants to read the first shared memory, the third process also needs to establish its own virtual address space and the first shared memory. After the mapping relationship is established, the third process can read the first shared memory.

In this embodiment of the present application, the second process and the third process may establish a mapping relationship between their own virtual address space and the first shared memory through a memory map (memory map, mmap for short) mechanism. Among them, mmap is a method of memory mapping files, that is, a file is mapped to the virtual address space of the process, and a one-to-one mapping relationship between the file address and the virtual address space of the process is realized. After implementing such a mapping relationship, the process can use the pointer to read and write operations to the virtual address space, so as to realize the read and write operations to the file.

Next, the process of establishing the mapping relationship between their own virtual address space and the first shared memory by the second process and the third process through the mmap mechanism will be described in detail.

Taking the second process establishing the mapping relationship between its own virtual address space and the first shared memory through the mmap mechanism as an example, the process may include:

The first and second processes call the library function mmap in user space.

In the second step, the second process opens up a first mapping area in its own virtual address space.

The first mapping area is an area in the virtual address space of the second process that establishes a mapping relationship with the first shared memory.

In the third step, the second process allocates a virtual area structure to the first mapping area, and then initializes each field of the virtual area structure.

In the fourth step, the second process inserts the virtual area structure into the linked list or tree of the first mapping area of the second process.

The fifth step, the second process finds the file descriptor of the first shared file in the file descriptor table through the file pointer to be mapped, and links to the kernel "open file set" through the file descriptor of the first shared file The file structure of the first shared file.

In the sixth step, the second process links to the file organization (file operations) module through the file structure of the first shared file, and calls the kernel function mmap.

In the seventh step, the second process locates the address of the first shared file through a virtual file system index (inode) module.

In the eighth step, the second process establishes a page table through the function of mapping the device memory to the user space address (remap_pfn_range).

Through the above eight steps, the mapping relationship between the first mapping area and the first shared file is established, that is, the mapping relationship between the first mapping area and the first shared memory is established.

It can be understood that the process of establishing the mapping relationship between the virtual address space of the third process and the first shared memory, that is, the process of establishing the mapping relationship between the second mapping area and the first shared memory, is the same as the process of establishing the mapping relationship between the first mapping area and the first shared memory. The process of establishing the mapping relationship of the shared memory is similar, and will not be repeated here. The second mapping area is an area in the virtual address space of the third process that establishes a mapping relationship with the first shared memory. For ease of description, in the following embodiments of the present application, the first mapping relationship is used to represent the first mapping area and the first shared memory. The mapping relationship between the first shared memories is represented by the second mapping relationship between the second mapping area and the first shared memory.

S102. The second process writes the first data into the first mapping area, and maps the first data from the first mapping area to the first shared memory according to the first mapping relationship, and the third process maps the first data to the first shared memory according to the second mapping relationship A piece of data is mapped from the first shared memory to the second mapping area, thereby realizing one-way communication from the second process to the third process.

After the first mapping relationship and the second mapping relationship are established, the second process writes the first data into the first mapping area, and then maps the first data from the first mapping area to the first shared memory according to the first mapping relationship, It can be understood that the second process performs a write operation on the first shared memory, and writes the first data into the first shared memory. The third process maps the first data in the first shared memory to the first mapping area according to the second mapping relationship. It can be understood that the third process performs a read operation on the first shared memory and reads from the first shared memory the first data.

In a more specific embodiment, the second process may include a writing thread for writing the first data in the first mapping area, and the third process may include a reading thread for reading the first data from the second mapping area . The writing thread is activated when the second process has the first data to be written, so as to notify the third process that the first data needs to be read. The read thread is activated when the third process has the first data to be read, so as to read the first data, and after the reading is completed, notifies the second process that the first data is read.

It should be noted that after the first data is written into the first shared memory, the content in the first shared memory will be changed, but the first data will not be immediately written back to the first shared file to change the content in the first shared file. , but there is a delay for a period of time. After a certain period of time, the operating system will automatically write back the dirty page containing the first data to the corresponding first shared file, that is, the process of writing the first data to the first shared file is completed. . To synchronize the content of the first shared file with the content in the first shared memory, a refresh change (msync) function may be called to force synchronization. In this way, the first data written by the second process can be stored in the first shared file synchronously.

In a specific implementation, when the second process performs one-way communication with the third process through the first shared memory, it does not always release the first mapping relationship or release the second mapping relationship after reading and writing a small amount of data, but keeps the The mapping relationship between the respective mapping areas and the first shared memory until the communication is completed. In this way, the first data is always stored in the first shared memory and is not reclaimed by the second process. The first data is often collected by the second process after the second process and the third process have finished communicating.

The second process reclaims the first data, indicating that the communication between the second process and the third process ends, the second process can cancel the first mapping relationship, and the third process can cancel the second mapping relationship. After the mapping relationship is released, the first process may release the resources occupied by the first shared memory.

In order to further improve the performance of communication between the second process and the third process, in a specific implementation manner, the first shared memory further includes a disruptor queue, and the second process writes the first data into the first shared memory. In the shared memory, the specific process for the third process to read the first data from the first shared memory is as follows:

A1. The second process writes the first data into the first mapping area.

A2. The second process maps the first data from the first mapping area to the disruptor queue.

Specifically, the second process maps the first data from the first mapping area to the disruptor queue in the first shared memory according to the first mapping relationship.

A3. The third process maps the first data from the disruptor queue to the second mapping area.

Specifically, the third process maps the first data from the disruptor queue to the second mapping area according to the second mapping relationship.

It can be seen that, in this embodiment, the process of transmitting the first data from the second process to the third process is realized by mapping, and there is no need to copy the first data, which can meet the needs of zero-time communication in some inter-process communication scenarios. Data copy requirements.

In a possible implementation manner, in addition to the disruptor queue, the first shared memory further includes a preset shared area, where the preset shared area is used to store the first data. The second process writes the first data into the first shared memory, and the specific process for the third process to read the first data from the first shared memory is:

B1. The second process writes the first data into the first mapping area.

B2. The second process maps the first data from the first mapping area to the preset shared area.

Specifically, the second process maps the first data from the first mapping area to a preset shared area in the first shared memory according to the first mapping relationship.

B2. The second process outputs the output stream including the storage information of the first data from the preset shared area to the disruptor queue, wherein the storage information of the first data is the first address information of the first data in the preset shared area and length information, or, the first address information and the last address information of the first data in the preset shared area.

B3. The third process maps the storage information of the first data from the disruptor to the second mapping area,

B4. The third process reads the first data from the preset shared area according to the address information and the length information of the first data.

Specifically, the third process maps the first data from the disruptor queue to the second mapping area according to the second mapping relationship.

It can be seen that in this embodiment, in the process of transmitting the first data from the second process to the third process, the second process needs to output the output stream including the storage information of the first data from the preset shared memory area To the disruptor queue, a data copy needs to be performed, which can meet the requirement of a data copy in some inter-process communication scenarios.

Next, the working principle of the disruptor queue is introduced.

As shown in FIG. 5 , in FIG. 5 , thread A represents a write thread in a second process with read-write permission, and thread B and thread C represent read threads in two processes with read-only permission.

As shown in Figure 5, in the disruptor queue, there is a ring buffer (ring buffer), and there are many positions called slots above the ring buffer, such as slot 1, slot 2, slot 3 in Figure 5... Slot 10, Slot 11, Slot 12. Each data in the ring buffer is indexed by a sequence number. In a specific implementation, the sequence number can be set to be the same as the slot position number. The ring buffer maintains the sequence number of the latest written data. This sequence number is always increasing. For example, data has been written to slot 10 and slot 11. The sequence number of the latest written data maintained by the ring buffer is 11. Event After receiving the data A to be written by thread A, the processor can learn from the ring buffer that the next slot to write data A is 12, then thread A writes the data A to be written to slot 12. . After writing, the ring buffer will update the sequence number of the last written data A to 12, and notify thread B and thread C that the data with sequence number 12 can be read. After receiving the notification, thread B and thread C read data A according to the sequence number 12 of the received data A. In the case that thread B and thread C do not receive the notification, thread B and thread C will enter the waiting state, waiting for data A to be written to the ring buffer by thread A, and, once data A is written to the ring buffer, thread B And thread C will be notified, and then thread B and thread C can read data A according to the received sequence number 12.

It should be noted that thread B and thread C do not directly read the data A of the ring buffer, but call the wait for method of the sequence barrier object according to the received sequence number 12, The sequence barrier object transmits the sequence number 12 it needs to access, and the sequence barrier object obtains the data A in slot 12 in the ring buffer according to the sequence number 12, and then returns it to thread B and thread C.

It can be understood that thread B and thread C read data A after receiving the notification from the ring buffer. If thread A has not finished writing data A, thread B and thread C will not read data A, so It can prevent thread A from performing a write operation while thread B or thread C performs a read operation. At the same time, thread B and thread C read data A from the sequence barrier object according to the received sequence number 12. Thread B and thread C do not directly operate the ring buffer. Therefore, for the ring buffer, thread B and thread C do not directly operate the ring buffer. Thread C will not generate resource contention, so there is no need to lock thread B and thread C.

In a specific application, the number of slots in the ring buffer can be customized and set, and the number of slots in the ring buffer is 2 ⁿ , where n is a positive integer. Therefore, the ring buffer can have a data buffer size ranging from tens of thousands to tens of millions. Therefore, using the disruptor queue in the first shared memory can also avoid the problem of memory overflow when the write operation speed of thread A is too fast.

In the inter-process communication method provided by the embodiment of the present application, by using the disruptor queue in the first shared memory, it can be ensured that when the second process writes the first shared memory, the third process cannot read the first shared memory operation, and also avoids the use of locks when multiple processes perform read operations on the first shared memory. At the same time, the present application uses a disruptor queue in the first shared memory to support repeated reading and writing of the first shared memory by a process, which can effectively improve the throughput of inter-process information and further improve the performance of inter-process communication.

In addition, it can also be seen that, in the inter-process communication method provided by the embodiment of the present application, when the first shared memory only includes the disruptor queue, the one-way communication process from the second process to the third process does not require data copying; When the first share includes a preset shared area in addition to the disruptor queue, the one-way communication process from the second process to the third process needs to perform a data copy. The inter-process communication method provided by the embodiment of the present application is not only applicable to the inter-process communication scenario that requires zero data copies, but also to the inter-process communication scenario that requires one data copy, and has good flexibility.

In order to further improve the security reliability of the communication between the second process and the third process, in a specific implementation manner, before the second process writes the first data into the first mapping area, the second process needs to allocate the first Heap memory, the first heap memory is used to store the control information of the second process, and then the second process obtains the control information of the second process from the first heap memory, so that the second process can store the control information of the second process according to the control information of the second process. A data is written into the first mapping area. Before the third process maps the first data from the first shared memory to the second mapping area, the third process needs to allocate the second heap memory, and the second heap memory is used to store the control information of the third process, and then the third process needs to The control information of the third process is obtained from the second heap memory, so that the third process can map the first data from the first shared memory to the second mapping area according to the control information of the third process.

Wherein, the control information of the second process may include information that the process communicating with the second process is the third process, and the control information of the second process may also include read and write permission information of the first shared memory owned by the second process, etc., There is no specific limitation here. The control information of the third process may include information that the process communicating with the third process is the second process, and the control information of the third process may also include read-only permission information of the first shared memory owned by the third process, etc. Here There is no specific limitation.

In the above embodiment, by storing the control information of the second process in the first heap memory (the heap memory of the first process), and storing the control information of the third process in the second heap memory (the heap memory of the third process), When the second process communicates with the third process, the second process and the third process can directly obtain their own control information from their own heap memory for communication, and the efficiency of inter-process communication is high. At the same time, by storing the control information of the second process in the first heap memory and storing the control information of the third process in the second heap memory, the control information of the second process and the control information of the third process can also be stored separately. , which is beneficial for the second process and the third process to be independent and non-interfering with each other during operation. When one of the second process and the third process fails, the failure will not spread to the other process.

In practical applications, the second process and the third process can call the memory allocation (memory allocation, abbreviated as malloc) function or create (new) function to allocate the corresponding first heap memory and second heap memory, and the second process can decide The size of the allocated first heap memory, the third process can decide the size of the allocated second heap memory, the second process and the third process can also release the corresponding first heap through the release (free) function or the delete (delete) function memory and the second heap.

It should be noted that the heap memory allocated by the process is allocated from the virtual address space of the process itself. For example, the first heap memory allocated by the second process is the memory in the virtual address space of the second process itself. As shown in FIG. 6 , it can be seen from FIG. 6 that the virtual address space of the second process includes heap memory, stack memory, shared memory mapping area (first mapping area), and the like. It can be seen from FIG. 6 that the first mapping area is located between the heap memory (the first heap memory) of the second process and the stack memory of the second process. That is to say, the first heap memory and the first mapping area are two different pieces of memory in the virtual address space of the second process.

The first mapping area stores the shared memory information of the second process, and the shared memory information of the second process may include information such as the first mapping relationship or the first data written into the first mapping area by the second process, which will not be described here. Specific restrictions. The second mapping area stores the shared memory information of the third process, and the shared memory information of the third process may include information such as the second mapping relationship or the first data read from the first shared memory, which is not specifically limited here.

In the above embodiment, by storing the control information of the second process in the first heap memory, and storing the shared memory information of the second process in the first mapping area, the first heap memory and the first mapping area are different memories, so Implementing separate storage of the control information of the second process and the shared memory information of the second process is beneficial to ensure the security of the shared memory information of the second process. Similarly, the control information of the third process is stored in the second heap memory, and the shared memory information of the third process is stored in the second mapping area, and the second heap memory and the second mapping area are different memories, so that the third The separate storage of the control information of the process and the shared memory information of the third process is beneficial to ensure the safety of the shared memory information of the third process.

In another specific implementation, before the second process writes the first data into the first mapping area, the first process needs to allocate a third heap memory, and the third heap memory is used to store the control information of the second process, Then the second process sends a first information acquisition request to the first process, requesting to acquire the control information of the second process from the third heap memory. After the second process acquires the control information of the second process returned by the first process, the first process The second process may write the first data into the first mapping area according to the control information of the second process. Before the third process maps the first data from the first shared memory to the second mapping area, the third process needs to allocate the second heap memory, and the second heap memory is used to store the control information of the third process, and then the third process needs to The control information of the third process is obtained from the second heap memory, so that the third process maps the first data from the first shared memory to the second mapping area according to the control information of the third process.

In the above embodiment, by storing the control information of the second process in the heap memory of the first process, and storing the control information of the third process in the heap memory of the third process, when the second process communicates with the third process, The second process needs to first send a request for obtaining control information to the first process, and then obtain the control information of the second process returned by the first process. The third process can obtain its own control information from its own heap memory. It can be seen that, The communication efficiency of the second process is lower than that of the third process. That is to say, the method of storing process control information in the process's own heap memory is suitable for processes with high performance requirements; the method of storing process control information in the heap memory of the first process is suitable for lower performance requirements. process. It can be seen that the above method is not only suitable for processes with high communication performance requirements, but also suitable for processes with low communication performance requirements, and has high flexibility. At the same time, by storing the control information of the second process in the heap memory of the first process, and storing the control information of the third process in the heap memory of the third process, the control information of the second process and the control of the third process can also be realized. The separate storage of information is beneficial for the second process and the third process to be independent of each other and not interfere with each other during operation. When one of the second process and the third process fails, the failure will not spread to the other process.

It can also be known from the above embodiment that the third heap memory is the memory in the virtual address space of the first process, the first mapping area is the memory in the virtual address space of the second process, and there is process isolation between the first process and the second process. , so it can be understood that the third heap memory and the first mapping area are also two different pieces of memory. In addition, it can be known from the above embodiment that the second heap memory and the second mapping area are two different pieces of memory in the virtual address space of the third process.

In the above solution, the control information of the second process is stored in the third heap memory, and the shared information of the second process is stored in the first mapping area, so that the control information of the second process and the shared memory information of the second process can be separated. The storage is beneficial to ensure the safety of the shared memory information of the second process. At the same time, the control information of the third process is stored in the second heap memory, and the shared memory information of the third process is stored in the second mapping area, so that the control information of the third process and the shared memory information of the third process can be stored separately. , which is beneficial to ensure the security of the shared memory information of the third process.

In another specific implementation manner, before the second process writes the first data into the first mapping area, the second process needs to allocate a first heap memory, and the first heap memory is used to store the control information of the second process, Then the second process acquires the control information of the second process from the first heap memory, so that the second process writes the first data into the first mapping area according to the control information of the second process. Before the third process maps the first data from the first shared memory to the second mapping area, the first process needs to allocate a third heap memory, and the third heap memory is used to store the control information of the third process, and then the third process sends the The first process sends a second request for obtaining information, requesting to obtain the control information of the third process from the third heap memory. After the third process obtains the control information of the third process returned by the first process, the third process can The control information of the three processes maps the first data from the first shared memory to the second mapping area.

It can also be known from the above embodiment that the third heap memory is the memory in the virtual address space of the first process, the second mapping area is the memory in the virtual address space of the third process, and there is process isolation between the first process and the third process. , so it can be understood that the third heap memory and the second mapping area are also two different pieces of memory. In addition, it can also be known that the first heap memory and the first mapping area are two different pieces of memory in the virtual address space of the second process.

In the above embodiment, the control information of the second process is stored in the first heap memory, and the shared information of the second process is stored in the first mapping area, which can realize the control information of the second process and the shared memory information of the second process. Separate storage is beneficial to ensure the safety of the shared memory information of the second process. At the same time, the control information of the third process is stored in the third heap memory, and the shared memory information of the third process is stored in the second mapping area, so that the control information of the third process and the shared memory information of the third process can be stored separately. , which is beneficial to ensure the security of the shared memory information of the third process.

It can also be seen from the above embodiment that the heap memory of the first process, the heap memory of the second process, the heap memory of the third process, the first mapping area, the second mapping area, and the first shared memory are different memories. That is to say, the embodiment of the present application can realize the separate storage of the control information of the second process, the control information of the third process, the shared memory information of the second process, and the shared memory information of the third process and the first shared memory information. It is beneficial to ensure the security of the first shared memory information.

The first shared memory may store first shared memory information, and the first shared memory information may include the mapping relationship between the first shared memory and the first mapping area, the mapping relationship between the first shared memory and the second mapping area, or the second process The information such as the first data written in the first shared memory is not specifically limited here.

In order to further ensure the reliability of the communication between the second process and the third process, as an embodiment of the present application, the first process includes a detection thread, which is used for when the second process communicates with the third process through the first shared memory, Detect the status of the second process and the third process in real time. When the first process detects that the second process or the third process is reset, the first process can promptly notify the second process and the third process that no reset occurs. So that the communication connection can be terminated in time, and the occupied first shared memory resource can be released in time. Among them, the process reset means that the state of the process returns to the initial state, and the process waits to be executed again.

In this embodiment, for the one-way communication between the second process and the third process, once the first process detects that the communication between the second process and the third process is completed, the first process can close the first shared memory , release the first shared memory resource in time.

In order to further ensure the reliability of the communication between the second process and the third process, as an embodiment of the present application, the first process further includes a recovery shared memory thread, wherein the recovery shared memory thread is the highest running level among the threads included in the first process When the second process communicates with the third process through the first shared memory, if the first process is reset and needs to be restarted, the thread that runs first in the first process is the recovery shared memory thread, and the first process includes other threads, such as the detection thread, when resuming the shared memory thread running, the detection thread can be delayed or suspended, giving resources to the recovery shared memory thread, and the recovery shared memory thread can resume the first shared memory at the fastest speed. Memory.

It can be seen from the above embodiments that, in the inter-process communication method provided by the embodiments of the present application, the first process can also detect in real time whether the second process or the third process is reset, and in the case where the second process or the third process is reset. , terminate the communication connection between the second process and the third process in time, and release the resources occupied by the first shared memory. At the same time, the first process may also set the running level of the restoration shared memory thread to the highest priority, so as to quickly restore the first shared memory when the first process needs to be restarted.

It can also be seen from the above embodiments that the service mode adopted by the inter-process communication method provided by the embodiment of the present application is also the C/S mode. The first process, as a server process, provides a first shared memory for the second process and the third process, and the second process and the third process, as client processes, communicate using the first shared memory provided by the first process.

In the inter-process communication method provided by the embodiment of the present application, the first shared memory between the second process and the third process is created by the first process, the second process writes the first data into the first mapping area, and according to the first mapping The relationship maps the first data from the first mapping area to the first shared memory, and the third process maps the first data from the first shared memory to the second mapping area according to the second mapping relationship, so as to realize the second process to the third One-way communication between processes. Wherein, the process of transmitting the first data from the second process to the third process is realized by mapping the first mapping relationship and the second mapping relationship, and it can be realized without the system calling the kernel into the kernel space, without data copying and system overhead. Small, high communication efficiency. Moreover, when the inter-process communication method provided by the present application is applied to embedded devices with various operating systems, since the kernel state is not introduced in the one-way communication process from the second process to the third process, there is no need to consider the single board and the operating system. The problem of adaptation, the operation is simple, and the portability is strong. Meanwhile, in addition to the first process, only the second process has the read and write authority of the first shared memory, which can prevent multiple processes from simultaneously writing to the first shared memory, resulting in confusion of data in the first shared memory. In addition, the second process and the third process are both processes registered in the first process, the first process can verify the identities of the second process and the third process, and only has the read and write permissions of the first shared memory or Only processes with read-only permissions can access the first shared memory, which can prevent malicious programs from tampering with or destroy data in the first shared memory, and can effectively improve the security and reliability of inter-process communication.

The above embodiments describe in detail the implementation process of the one-way communication between the second process and the third process. Next, the process of implementing the one-way communication between the third process and the second process by the inter-process communication method provided by the present application is explained.

Please refer to Fig. 7. As shown in Fig. 7, the method includes:

S201. The first process creates a second shared memory between the second process and the third process.

The first process has read and write rights to the second shared memory, the third process has read and write rights to the second shared memory, the second process has read-only rights to the second shared memory, and the third mapping area and the second shared memory There is a third mapping relationship between them, there is a fourth mapping relationship between the fourth mapping area and the third shared memory, and the third mapping area is an area in the virtual address space of the third process that establishes a mapping relationship with the second shared memory, and the fourth The mapping area is an area in the virtual address space of the second process that establishes a mapping relationship with the second shared memory;

The process of creating the second shared memory between the second process and the third process by the first process is similar to the process of creating the first shared memory between the second process and the third process by the first process described in S01 , the process of configuring the read-only permission of the second shared memory by the first process for the second process, and the process of configuring the read-write permission of the second shared memory for the third process is the same as the process of configuring the first process for the second process in S101. The read-write permission of the shared memory and the process of configuring the read-only permission of the first shared memory for the third process are similar. For details, please refer to the relevant description in S101, which will not be repeated here. The third process establishes the mapping relationship between the third mapping area and the second shared memory, and the second process establishes the mapping relationship between the fourth mapping area and the second shared memory, and establishes the first mapping area with the second process in S101 The process of the mapping relationship between the first shared memories is similar, and will not be repeated here.

S202. The third process writes the second data into the third mapping area, and maps the second data from the third mapping area to the second shared memory according to the third mapping relationship, and the second process maps the second data to the second shared memory according to the fourth mapping relationship. The second data is mapped from the second shared memory to the fourth mapping area, thereby realizing one-way communication from the third process to the second process.

The third process writes the second data into the third mapping area, and maps the second data from the third mapping area to the second shared memory according to the third mapping relationship. It can be understood that the third process maps the second shared memory to the second shared memory A write operation is performed, and the second data is written into the second shared memory. According to the mapping relationship between the fourth mapping area and the second shared memory, the second process maps the second data from the second shared memory to the fourth mapping area. It can be understood that the second process reads the second shared memory. The second data is read from the second shared memory.

In the inter-process communication method provided by the embodiment of the present application, a second shared memory between the second process and the third process is created by the first process, the third process writes the second data into the third mapping area, and according to the third mapping The relationship maps the second data from the third mapping area to the second shared memory, and the third process maps the second data from the second shared memory to the fourth mapping area according to the fourth mapping relationship. Thereby, one-way communication from the third process to the second process is realized. Wherein, the process of transmitting the second data from the third process to the second process is realized by mapping the third mapping relationship and the fourth mapping relationship, which can be realized without the system calling the kernel into the kernel space, without data copying and system overhead. Small, high communication efficiency. Moreover, when applied to embedded devices with various operating systems, since the kernel state is not introduced in the one-way communication process from the third process to the second process, there is no need to consider the problem of adapting the board and the operating system, and the operation is simple. Portable. Meanwhile, in addition to the first process, only the third process has read and write permissions to the second shared memory, which can prevent multiple processes from simultaneously writing to the second shared memory, resulting in confusion of data in the second shared memory. In addition, both the second process and the third process are processes registered in the first process, the first process can verify the identities of the second process and the third process, and only has the read and write permissions of the second shared memory or Only processes with read-only permissions can access the second shared memory, which can prevent malicious programs from tampering with or destroy data in the second shared memory, and can effectively improve the security and reliability of inter-process communication.

It can be seen from the above embodiments that the one-way communication between the second process and the third process is implemented through S101 and S102, and the one-way communication between the third process and the second process is implemented through S201 and S202. It can be understood that the two-way communication between the second process and the third process can be implemented through S101, S102, S201 and S202, and the process of implementing the two-way communication between the second process and the third process will not be repeated here.

In order to better understand and implement the above solutions of the embodiments of the present application, a more specific scenario of inter-process communication is described below.

Please refer to FIG. 8 , which is a schematic diagram of interaction of an inter-process communication method provided by an embodiment of the present application. As shown in Figure 8, the inter-process communication method may include:

S301. The second process sends a registration request to the first process.

The registration request may include information such as the UID or PID of the second process, for the first process to verify the identity of the second process, and to register the second process according to the information such as the UID or PID of the second process.

S302. The first process receives the registration request sent by the second process, registers the second process to obtain registration information, creates a first shared memory, and configures the second process to have read and write permissions of the first shared memory.

The first process may create a first shared memory according to information such as the UID or PID of the second process, the first shared memory may have a shared memory identifier, and the first shared memory identifier may be based on the physical address of the first shared memory or the second process. UID or PID and other information to name.

S303. The first process sends the registration information to the second process.

S304. The second process receives the registration information returned by the first process, opens up a first mapping area, and establishes a mapping relationship between the first mapping area and the first shared memory.

The registration information may include a first shared memory identifier, which is used by the second process to establish a mapping relationship between the first mapping area and the first shared memory.

S305. The second process sends a connection request to the first process, where the connection request is used to request the first process to establish a connection between the second process and the third process, where the third process has been registered in the first process.

S306. The first process receives the connection request, determines the third process according to the connection request, and configures the third process to have the read-only permission of the first shared memory.

The connection request sent by the second process may include information such as the UID or PID of the third process, for the first process to search for the third process according to the identification information of the third process included in the connection request.

S307. The first process sends the connection request to the third process.

S308. The third process receives the connection request, opens up a second mapping area, and establishes a mapping relationship between the second mapping area and the first shared memory.

The connection request may further include a first shared memory identifier, which is used by the third process to establish a mapping relationship between the second mapping area and the first shared memory.

S309. The third process returns a connection response to the first process.

S310. The first process receives the connection response sent by the third process, and forwards the connection response to the second process.

S311. The second process receives the connection response, obtains the control information of the second process from the first heap memory, and writes the first data into the disruptor queue in the first shared memory through the first mapping area.

S312 , the third process acquires the control information of the third process from the second heap memory, and reads the first data from the disruptor queue in the first shared memory through the second mapping area.

An inter-process communication method according to an embodiment of the present application is described in detail above. Based on the same inventive concept, an inter-process communication device according to an embodiment of the present application is provided below. The inter-process communication device provided by the present application is used for Various terminal devices for inter-process communication, including but not limited to electronic devices such as smart phones, tablet computers, and laptop computers. The terminal device may be an electronic device constructed based on an operating system such as android, linux, or windows, or may be constructed based on other systems as required, which is not specifically limited here.

Referring to FIG. 9 , FIG. 9 is a schematic structural diagram of an inter-process communication apparatus 100 provided by an embodiment of the present application. As shown in FIG. 9 , the inter-process communication apparatus 100 provided by an embodiment of the present application includes at least: a creation module 110 and a communication module 120, of which,

The creation module 110 is configured to create a first shared memory between the second process and the third process through the first process, wherein the first process, the second process and the third process run in the user space, and the first process The shared memory has read and write permissions, the second process has read and write permissions to the first shared memory, the third process has read-only permissions to the first shared memory, the second process and the third process are both registered in the first process, and the first There is a first mapping relationship between the mapping area and the first shared memory, a second mapping relationship between the second mapping area and the first shared memory, and the first mapping area is established in the virtual address space of the second process with the first shared memory A mapping relationship area, and the second mapping area is an area in the virtual address space of the third process that establishes a mapping relationship with the first shared memory.

The communication module 120 is configured to write the first data into the first mapping area through the second process, map the first data from the first mapping area to the first shared memory according to the first mapping relationship, and also use the third process to map the first data from the first mapping area to the first shared memory according to the first mapping relationship. The second mapping relationship is used to map the first data from the first shared memory to the second mapping area, so as to realize one-way communication from the second process to the third process.

In this embodiment of the present application, the creation module 110 is further configured to:

The creation module 110 configures, through the first process, the second process to have the read-write permission of the first shared memory, and configures the third process to have the read-only permission of the first shared memory.

In this embodiment of the present application, the creation module 110 is specifically used for:

The creation module 110 configures the second process to have the read-write permission of the first shared memory through the access control list ACL, and configures the third process to have the read-only permission of the first shared memory through the first process.

In this embodiment of the present application, before the second process writes the first data into the first mapping area, the apparatus further includes: an allocation module 130 and an acquisition module 140;

The allocation module 130 is configured to allocate the first heap memory by the second process, and the first heap memory is used to store the control information of the second process.

The obtaining module 140 is configured to obtain the control information of the second process from the first heap memory by the second process, so that the second process writes the first data into the first mapping area according to the control information of the second process.

Before the third process maps the first data from the first shared memory to the second mapping area, the allocation module 130 is further configured to allocate a second heap memory by the third process, and the second heap memory is used to store the control of the third process information.

The obtaining module 140 is further configured to obtain the control information of the third process from the second heap memory through the third process, so that the third process maps the first data from the first shared memory to the second process according to the control information of the third process map area.

In the embodiment of the present application, the first heap memory and the first mapping area are different memories, the first mapping area is used to store the shared memory information of the second process, and the second heap memory and the second mapping area are different memories, The second mapping area is used to store the shared memory information of the third process.

In this embodiment of the present application, before the second process writes the first data into the first mapping area, the apparatus further includes a sending module 160;

The allocation module 130 is configured to allocate a third heap memory by the first process, and the third heap memory is used to store control information of the second process.

The obtaining module 140 is configured to receive, through the first process, a first obtaining information request sent by the second process, wherein the first obtaining information request is used to request to obtain control information of the second process from the third heap memory.

The sending module 160 is configured to send the control information of the second process to the second process through the first process according to the first acquisition information request, so that the second process writes the first data into the first map according to the control information of the second process area.

Before the third process maps the first data from the first shared memory to the second mapping area, the allocation module 130 is further configured to allocate a second heap memory by the third process, and the second heap memory is used to store the control of the third process information.

The obtaining module 140 is further configured to obtain the control information of the third process from the second heap memory through the third process, so that the third process maps the first data from the first shared memory to the second process according to the control information of the third process map area.

In this embodiment of the present application, the third heap memory and the first mapping area are different memories, the first mapping area is used to store the shared memory information of the second process, and the second heap memory and the second mapping area are different memories, The second mapping area is used to store the shared memory information of the third process.

In this embodiment of the present application, before the second process writes the first data into the first mapping area, the allocation module 130 is configured to allocate the first heap memory by the second process, and the first heap memory is used to store the data of the second process. control information.

The obtaining module 140 is configured to obtain the control information of the second process from the first heap memory by the second process, so that the second process writes the first data into the first mapping area according to the control information of the second process.

Before the third process maps the first data from the first shared memory to the second mapping area, the apparatus further includes a receiving module 150;

The allocation module 130 is configured to allocate a third heap memory by the first process, and the third heap memory is used to store control information of the third process.

The receiving module 150 is configured to receive, through the first process, a second information acquisition request sent by the third process, where the second information acquisition request is used to request to acquire control information of the third process from the third heap memory.

The sending module 160 is configured to send the control information of the third process to the third process according to the second information acquisition request through the first process, so that the third process can send the first data from the first shared memory to the third process according to the control information of the third process. Mapped to the second mapping area.

In the embodiment of the present application, the first heap memory and the first mapping area are different memories, the first mapping area is used to store the shared memory information of the second process, and the third heap memory and the second mapping area are different memories, The second mapping area is used to store the shared memory information of the third process.

In this embodiment of the present application, the first process includes a detection thread, and the apparatus further includes a detection module 170, and the detection module 170 is specifically used for:

The detection module 170 detects whether the second process or the third process is reset by the detection thread. When the detection module 170 detects that the second process or the third process is reset, it notifies the second process and the third process that there is no reset by the detection thread. The process that occurs the reset terminates the communication and frees the first shared memory.

In the embodiment of the present application, the first process includes a recovery shared memory thread, and the recovery shared memory thread is the thread with the highest running level among the threads included in the first process. The device further includes a recovery module 180, and the recovery module 180 is specifically used for:

When the first process is restarted, the restoration module 180 restores the first shared memory by restoring the shared memory thread.

In this embodiment of the present application, the first shared memory includes a destroyer queue, and the communication module 120 is specifically configured to:

The communication module 120 maps the first data from the first mapping area to the destroyer queue through the second process, and then maps the first data from the destroyer queue to the second mapping area through the third process.

In this embodiment of the present application, the creation module 110 is further configured to create a second shared memory between the second process and the third process through the first process, wherein the first process has read and write permissions to the second shared memory, and the first process The three processes have read and write permissions to the second shared memory, the second process has read-only permissions to the second shared memory, a third mapping relationship exists between the third mapping area and the second shared memory, and the fourth mapping area and the second shared memory There is a fourth mapping relationship between the memories, the third mapping area is an area in the virtual address space of the third process that establishes a mapping relationship with the second shared memory, and the fourth mapping area is in the virtual address space of the second process. The area established with the second shared memory The area of the mapping relationship;

The communication module 120 is further configured to write the second data into the third mapping area through the third process, and map the second data from the third mapping area to the second shared memory according to the third mapping relationship, and the second process according to the third mapping relationship. Four mapping relationships are used to map the second data from the second shared memory to the fourth mapping area, so as to realize one-way communication from the third process to the second process.

Specifically, for the specific implementation of the various operations performed by the above-mentioned inter-process communication apparatus 100, reference may be made to the descriptions in the relevant contents in the above-mentioned method embodiments, which are not repeated here for the sake of brevity of the description.

It should be understood that the inter-process communication apparatus 100 is only an example provided by the embodiment of the present application, and the inter-process communication apparatus 100 may have more or less components than those shown in FIG. 9 , and two or more components may be combined. components, or may be implemented with different configurations of components.

An embodiment of the present application further provides another inter-process communication device. Referring to FIG. 10 , FIG. 10 is a schematic structural diagram of an inter-process communication device 200 provided by the present application. The device includes: a processor 210 , a communication interface 230 and a memory 220 , wherein the processor 210 , the communication interface 230 and the memory 220 are coupled through the bus 240 . in,

Processor 210 may include one or more general-purpose processors, where a general-purpose processor may be any type of device capable of processing electronic instructions, including CPUs, microprocessors, microcontrollers, main processors, controllers, and application-specific integrated circuit (application specific integrated circuit, ASIC) and so on. The processor 210 reads the program code stored in the memory 220, and cooperates with the communication interface 230 to execute part or all of the steps of the method executed by the inter-process communication apparatus 100 in the above embodiments of the present application.

Communication interface 230 may be a wired interface (eg, an Ethernet interface) or a wireless interface (eg, a cellular network interface or using a wireless local area network interface) for communicating with other computing nodes or devices. When the communication interface 230 is a wired interface, the communication interface 230 may use a protocol family above transmission control protocol/internet protocol (TCP/IP), for example, remote function call (RFC) protocol, simple object access protocol (SOAP) protocol, simple network management protocol (SNMP) protocol, common object request broker architecture (CORBA) protocol, and distributed protocols and many more.

The memory 220 may store program codes and program data. The program code includes: the code of the creation module 110, the code of the communication module 120, etc., and the program data includes: first data, second data, control information of the second process, control information of the third process, and so on. In practical applications, the memory 220 may include volatile memory (volatile memory), such as random access memory (random access memory, RAM); the memory may also include non-volatile memory (non-volatile memory), such as read-only memory (read-only memory, ROM), flash memory (flash memory), hard disk drive (HDD) or solid-state drive (solid-state drive, SSD) memory may also include a combination of the above-mentioned types of memory.

The bus 240 may be a peripheral component interconnect (PCI) bus or an extended industry standard architecture (extended industry standard architecture, EISA for short) bus or the like. The bus 240 can be divided into an address bus, a data bus, a control bus, and the like. For ease of presentation, only one thick line is used in FIG. 10, but it does not mean that there is only one bus or one type of bus.

It should be understood that the inter-process communication apparatus 200 is only an example provided by the embodiment of the present application, and the inter-process communication apparatus 200 may have more or less components than those shown in FIG. 10 , and two or more components may be combined. components, or may be implemented with different configurations of components.

Embodiments of the present application further provide a computer storage medium, where instructions are stored in the computer storage medium, and when the computer storage medium runs on a processor, the method steps in the foregoing method embodiments can be implemented, and the processor of the computer storage medium is executing the foregoing method. For the specific implementation of the steps, reference may be made to the specific operations of the foregoing method embodiments, which will not be repeated here.

Embodiments of the present application further provide a computer program product, which, when the computer program product is read and executed by a computer, implements some or all of the steps of the inter-process communication method described in the above method embodiments.

In the above embodiments, it may be implemented in whole or in part by software, hardware or any combination thereof. When implemented in software, it can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of the present application are generated. The computer may be a general purpose computer, special purpose computer, computer network, or other programmable device. The computer instructions may be stored in or transmitted from one computer readable storage medium to another computer readable storage medium, for example, the computer instructions may be downloaded from a website site, computer, server or data center Transmission to another website site, computer, server, or data center is by wire (eg, coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (eg, infrared, wireless, microwave, etc.). The computer-readable storage medium may be any available medium that can be accessed by a computer or a data storage device such as a server, data center, etc. that includes an integration of one or more available media. The usable media may be magnetic media (eg, floppy disks, hard disks, magnetic tapes), optical media (eg, digital video discs (DVDs)), or semiconductor media (eg, SSDs), and the like.

The steps in the method of the embodiment of the present application may be sequentially adjusted, combined or deleted according to actual needs; the modules in the device of the embodiment of the present application may be divided, combined or deleted according to actual needs.

The embodiments of the present application have been introduced in detail above, and the principles and implementations of the present application are described in this paper by using specific examples. The descriptions of the above embodiments are only used to help understand the methods and core ideas of the present application; at the same time, for Persons of ordinary skill in the art, based on the idea of the present application, will have changes in the specific implementation manner and application scope. In summary, the contents of this specification should not be construed as limitations on the present application.

Claims (27)

1. An inter-process communication method, the method comprising:

a first process creates a first shared memory between a second process and a third process, wherein the first process, the second process and the third process run in user space, the first process has read-write permission to the first shared memory, the second process has read-write permission to the first shared memory, the third process has read-only permission for the first shared memory, the second process and the third process are both registered in the first process, a first mapping relation is formed between a first mapping area and the first shared memory, a second mapping relation is formed between a second mapping area and the first shared memory, the first mapping region is a region in the second process virtual address space that establishes a mapping relationship with the first shared memory, the second mapping area is an area in the third process virtual address space, which establishes a mapping relation with the first shared memory;

the second process writes first data into the first mapping area, maps the first data from the first mapping area to the first shared memory according to the first mapping relation, and the third process maps the first data from the first shared memory to the second mapping area according to the second mapping relation, so that one-way communication from the second process to the third process is realized.

2. The method of claim 1, wherein after the first process creates the first shared memory between the second process and the third process, the method further comprises:

and the first process configures the second process with the read-write permission of the first shared memory, and configures the third process with the read-only permission of the first shared memory.

3. The method of claim 2, wherein the first process configuring the second process with read-write permission of the first shared memory and configuring the third process with read-only permission of the first shared memory comprises:

and the first process configures the second process with the read-write permission of the first shared memory through an Access Control List (ACL), and configures the third process with the read-only permission of the first shared memory.

4. The method of any of claims 1 to 3, wherein before the second process writes the first data to the first mapping region, the method further comprises:

the second process allocates a first bank memory, and the first bank memory is used for storing the control information of the second process;

the second process acquires the control information of the second process from the first stack memory, so that the second process writes the first data into the first mapping area according to the control information of the second process;

before the third process maps the first data from the first shared memory to the second mapping region, the method further includes:

the third process allocates a second heap memory, and the second heap memory is used for storing control information of the third process;

the third process acquires the control information of the third process from the second heap memory, so that the third process maps the first data from the first shared memory to the second mapping region according to the control information of the third process.

5. The method of claim 4, wherein the first heap memory and the first mapping region are different memories, the first mapping region is used for storing shared memory information of the second process, the second heap memory and the second mapping region are different memories, and the second mapping region is used for storing shared memory information of the third process.

6. The method of any of claims 1 to 3, wherein before the second process writes the first data to the first mapping region, the method further comprises:

the first process allocates a third heap memory, and the third heap memory is used for storing control information of the second process;

the first process receives a first information acquisition request sent by the second process, wherein the first information acquisition request is used for requesting to acquire control information of the second process from the third heap memory;

the first process sends the control information of the second process to the second process according to the first information acquisition request, so that the second process writes the first data into the first mapping area according to the control information of the second process;

before the third process maps the first data from the first shared memory to the second mapping region, the method further includes:

the third process allocates a second heap memory, and the second heap memory is used for storing control information of the third process;

the third process acquires the control information of the third process from the second heap memory, so that the third process maps the first data from the first shared memory to the second mapping region according to the control information of the third process.

7. The method of claim 6, wherein the third heap memory and the first mapping region are different memories, the first mapping region is used for storing shared memory information of the second process, the second heap memory and the second mapping region are different memories, and the second mapping region is used for storing shared memory information of the third process.

8. The method of any of claims 1 to 3, wherein before the second process writes the first data to the first mapping region, the method further comprises:

the second process allocates a first bank memory, and the first bank memory is used for storing the control information of the second process;

the second process acquires the control information of the second process from the first stack memory, so that the second process writes the first data into the first mapping area according to the control information of the second process;

before the third process maps the first data from the first shared memory to the second mapping region, the method further includes:

the first process allocates a third heap memory, and the third heap memory is used for storing control information of the third process;

the first process receives a second information acquisition request sent by the third process, wherein the second information acquisition request is used for requesting to acquire control information of the third process from the third heap memory;

and the first process sends the control information of the third process to the third process according to the second information acquisition request, so that the third process maps the first data from the first shared memory to the second mapping area according to the control information of the third process.

9. The method of claim 8, wherein the first heap memory and the first mapping region are different memories, the first mapping region is used for storing shared memory information of the second process, the third heap memory and the second mapping region are different memories, and the second mapping region is used for storing shared memory information of the third process.

10. The method of claim 1, wherein the first process comprises detecting a thread, the method further comprising:

the detection thread detects whether the second process or the third process is reset or not;

and under the condition that the second process or the third process is detected to be reset, the detection thread informs the second process and the third process that the reset process does not occur to terminate communication, and releases the first shared memory.

11. The method of claim 1, wherein the first process comprises a resume shared memory thread, and wherein the resume shared memory thread is a thread with a highest running level among threads included in the first process, the method further comprising:

and when the first process is restarted, the shared memory recovery thread recovers the first shared memory.

12. The method of any of claims 1 to 11, wherein the first shared memory includes a destroyer queue, and wherein the second process maps the first data from the first mapping region to the first shared memory, including:

the second process mapping the first data from the first mapping region to the destroyer queue;

the third process maps the first data from the first shared memory to the second mapping region, including:

the third process maps the first data from the destroyer queue to the second mapping region.

13. The method of claim 1, further comprising:

the first process creates a second shared memory between the second process and the third process, wherein the first process has read-write permission for the second shared memory, the third process has read-write permission for the second shared memory, the second process has read-only permission for the second shared memory, a third mapping region has a third mapping relationship with the second shared memory, a fourth mapping relationship has a fourth mapping relationship with the second shared memory, the third mapping region is a region in the virtual address space of the third process establishing a mapping relationship with the second shared memory, and the fourth mapping region is a region in the virtual address space of the second process establishing a mapping relationship with the second shared memory;

the third process writes the second data into the third mapping area, and maps the second data from the third mapping area to the second shared memory according to the third mapping relationship, and the second process maps the second data from the second shared memory to the fourth mapping area according to the fourth mapping relationship, thereby realizing one-way communication from the third process to the second process.

14. An interprocess communication apparatus, comprising:

a creating module, configured to create a first shared memory between a second process and a third process through a first process, where the first process, the second process, and the third process operate in a user space, the first process has a read-write permission for the first shared memory, the second process has a read-write permission for the first shared memory, the third process has a read-only permission for the first shared memory, the second process and the third process are both registered in the first process, a first mapping relationship is provided between a first mapping region and the first shared memory, a second mapping relationship is provided between a second mapping region and the first shared memory, the first mapping region is a region in a virtual address space of the second process that establishes a mapping relationship with the first shared memory, and the second mapping region is a region in a virtual address space of the third process that establishes a mapping relationship with the first shared memory An area;

a communication module, configured to write first data into the first mapping region through the second process, map the first data from the first mapping region to the first shared memory according to the first mapping relationship, and map the first data from the first shared memory to the second mapping region through the third process according to the second mapping relationship, so as to implement unidirectional communication from the second process to the third process.

15. The apparatus of claim 14, wherein after the first process creates the first shared memory between the second process and the third process, the creating module is further configured to:

the creating module configures, through the first process, the second process with the read-write permission of the first shared memory, and configures the third process with the read-only permission of the first shared memory.

16. The apparatus of claim 15, wherein the creation module is specifically configured to:

and the creating module configures the second process to have the read-write permission of the first shared memory through the first process by an Access Control List (ACL), and configures the third process to have the read-only permission of the first shared memory.

17. The apparatus according to any one of claims 14 to 16, wherein before the second process writes the first data to the first mapping region, the apparatus further comprises: a distribution module and an acquisition module;

the allocation module is configured to allocate a first bank memory through the second process, where the first bank memory is used to store control information of the second process;

the obtaining module is configured to obtain, by the second process, control information of the second process from the first heap memory, so that the second process writes the first data into the first mapping area according to the control information of the second process;

before the third process maps the first data from the first shared memory to the second mapping region, the allocating module is further configured to allocate a second heap memory through the third process, where the second heap memory is used to store control information of the third process;

the obtaining module is further configured to obtain, by the third process, control information of the third process from the second heap memory, so that the third process maps the first data from the first shared memory to the second mapping area according to the control information of the third process.

18. The apparatus of claim 17, wherein the first heap memory and the first mapping region are different memories, the first mapping region is configured to store shared memory information of the second process, the second heap memory and the second mapping region are different memories, and the second mapping region is configured to store shared memory information of the third process.

19. The apparatus according to any one of claims 14 to 16, wherein before the second process writes the first data to the first mapping region, the apparatus further comprises a sending module;

the allocation module is configured to allocate a third heap of memory through the first process, where the third heap of memory is used to store control information of the second process;

the obtaining module is configured to receive, by the first process, a first information obtaining request sent by the second process, where the first information obtaining request is used to request to obtain control information of the second process from the third heap memory;

the sending module is configured to send, by the first process according to the first information acquisition request, the control information of the second process to the second process, so that the second process writes the first data into the first mapping area according to the control information of the second process;

before the third process maps the first data from the first shared memory to the second mapping region, the allocating module is further configured to allocate a second heap memory through the third process, where the second heap memory is used to store control information of the third process;

the obtaining module is further configured to obtain, by the third process, control information of the third process from the second heap memory, so that the third process maps the first data from the first shared memory to the second mapping area according to the control information of the third process.

20. The apparatus of claim 19, wherein the third heap memory and the first mapping region are different memories, the first mapping region is configured to store shared memory information of the second process, the second heap memory and the second mapping region are different memories, and the second mapping region is configured to store shared memory information of the third process.

21. The apparatus according to any one of claims 14 to 16, wherein before the second process writes the first data into the first mapping region, the allocating module is configured to allocate, by the second process, a first bank memory, the first bank memory being configured to store control information of the second process;

the obtaining module is configured to obtain, by the second process, control information of the second process from the first heap memory, so that the second process writes the first data into the first mapping area according to the control information of the second process;

before the third process maps the first data from the first shared memory to the second mapping region, the apparatus further includes a receiving module;

the allocation module is configured to allocate a third heap of memory through the first process, where the third heap of memory is used to store control information of the third process;

the receiving module is configured to receive, through the first process, a second information acquisition request sent by the third process, where the second information acquisition request is used to request to acquire control information of the third process from the third heap memory;

the sending module is configured to send, by the first process according to the second information acquisition request, the control information of the third process to the third process, so that the third process maps the first data from the first shared memory to the second mapping area according to the control information of the third process.

22. The apparatus of claim 21, wherein the first heap memory and the first mapping region are different memories, the first mapping region is configured to store shared memory information of the second process, the third heap memory and the second mapping region are different memories, and the second mapping region is configured to store shared memory information of the third process.

23. The apparatus according to claim 14, wherein the first process comprises a detection thread, and the apparatus further comprises a detection module, and the detection module is specifically configured to:

the detection module detects whether the second process or the third process is reset or not through the detection thread;

and under the condition that the detection module detects that the second process or the third process is reset, the detection module informs the second process and a process which is not reset in the third process to terminate communication through the detection thread, and releases the first shared memory.

24. The apparatus according to claim 14, wherein the first process includes a resume shared memory thread, and the resume shared memory thread is a thread with a highest running level among threads included in the first process, and the apparatus further includes a resume module, and the resume module is specifically configured to:

when the first process is restarted, the recovery module recovers the first shared memory through the recovery shared memory thread.

25. The apparatus according to any one of claims 14 to 24, wherein the first shared memory comprises a destroyer queue, and wherein the communication module is specifically configured to:

the communication module maps the first data from the first mapping region to the destroyer queue through the second process;

the communication module maps the first data from the destroyer queue to the second mapping region through the third process.

26. The apparatus of claim 14, wherein the creating module is further configured to create a second shared memory between the second process and the third process via the first process, wherein the first process has read-write permission to the second shared memory, the third process has read-write permission to the second shared memory, the second process has read-only permission to the second shared memory, a third mapping relation is formed between a third mapping area and the second shared memory, a fourth mapping relation is formed between a fourth mapping area and the second shared memory, the third mapping region is a region in the third process virtual address space that establishes a mapping relationship with the second shared memory, the fourth mapping region is a region in the second process virtual address space, which establishes a mapping relationship with the second shared memory;

the communication module is further configured to write the second data into the third mapping region through the third process, and map the second data from the third mapping region to the second shared memory according to the third mapping relationship, and the second process maps the second data from the second shared memory to the fourth mapping region according to the fourth mapping relationship, so that unidirectional communication from the third process to the second process is achieved.

27. A computer storage medium, characterized in that it stores a computer program for inter-process communication, which computer program, when being executed by a processor, carries out the method according to any one of claims 1 to 13.

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