Description
I encountered this issue when synchronizing a directory using rclone (with sftp) to a server running AIX. Rclone was sending a SSH_FXP_STAT request to test if a directory is, well, a directory.
The STAT request was giving the directory's status as 'not a directory' despite being one.
The problem was in the toFileMode function in attrs.go
input filemode bits are 1 0100 0011 1111 1111
syscall.S_IFMT mask bits are 1 1111 0000 0000 0000
The different values tested are:
S_IFBLK 0 0110 0000 0000 0000
S_IFCHR 0 0010 0000 0000 0000
S_IFDIR 0 0100 0000 0000 0000
S_IFIFO 0 0001 0000 0000 0000
S_IFLNK 0 1010 0000 0000 0000
S_IFREG 0 1000 0000 0000 0000
S_IFSOCK 0 1100 0000 0000 0000
As you can see, none of the values matchs the input, and the leftmost bit is not used by any value.
The input would match S_IFDIR if the S_IFMT mask didn't test the leftmost bit.
I have searched the value of S_IFMT mask in other sftp implentations and in the ones I have found, they define S_IFMT as: 1111 0000 0000 0000
for example, the python implementation of stat:
https://github.com/python/cpython/blob/2.7/Lib/stat.py
Or this javascript implementation of sftp:
http://maverick-ng-javadocs.s3-website-eu-west-1.amazonaws.com/constant-values.html#com.sshtools.client.sftp.SftpFileAttributes.S_IFMT