src/hostip.c: Move macOS-specific calls into global init call

curl#7121 introduced a macOS system call to `SCDynamicStoreCopyProxies`, which is invoked every time an IP address needs to be resolved. However, this system call is not thread-safe, and macOS will kill the process if the system call is run first in a fork. To make it possible for the parent process to call this once and prevent the crash, only invoke this system call in the global initialization routine. Closes curl#11252
stanhu · Jun 5, 2023 · d21e2b2 · d21e2b2
1 parent c78a185
commit d21e2b2
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Showing 5 changed files with 108 additions and 21 deletions.
diff --git a/lib/Makefile.inc b/lib/Makefile.inc
@@ -179,6 +179,7 @@ LIB_CFILES =         \
   krb5.c             \
   ldap.c             \
   llist.c            \
+  macos.c            \
   md4.c              \
   md5.c              \
   memdebug.c         \
@@ -315,6 +316,7 @@ LIB_HFILES =         \
   inet_ntop.h        \
   inet_pton.h        \
   llist.h            \
+  macos.h            \
   memdebug.h         \
   mime.h             \
   mqtt.h             \

diff --git a/lib/easy.c b/lib/easy.c
@@ -63,6 +63,7 @@
 #include "slist.h"
 #include "mime.h"
 #include "amigaos.h"
+#include "macos.h"
 #include "warnless.h"
 #include "sigpipe.h"
 #include "vssh/ssh.h"
@@ -181,6 +182,13 @@ static CURLcode global_init(long flags, bool memoryfuncs)
   }
 #endif
 
+#if defined(__APPLE__)
+  if(Curl_macos_init()) {
+    DEBUGF(fprintf(stderr, "Error: Curl_macos_init failed\n"));
+    goto fail;
+  }
+#endif
+
   if(Curl_resolver_global_init()) {
     DEBUGF(fprintf(stderr, "Error: resolver_global_init failed\n"));
     goto fail;

diff --git a/lib/hostip.c b/lib/hostip.c
@@ -67,10 +67,6 @@
 #include "curl_memory.h"
 #include "memdebug.h"
 
-#if defined(ENABLE_IPV6) && defined(CURL_OSX_CALL_COPYPROXIES)
-#include <SystemConfiguration/SCDynamicStoreCopySpecific.h>
-#endif
-
 #if defined(CURLRES_SYNCH) &&                   \
   defined(HAVE_ALARM) &&                        \
   defined(SIGALRM) &&                           \
@@ -743,23 +739,6 @@ enum resolve_t Curl_resolv(struct Curl_easy *data,
         return CURLRESOLV_ERROR;
     }
 
-#if defined(ENABLE_IPV6) && defined(CURL_OSX_CALL_COPYPROXIES)
-    {
-      /*
-       * The automagic conversion from IPv4 literals to IPv6 literals only
-       * works if the SCDynamicStoreCopyProxies system function gets called
-       * first. As Curl currently doesn't support system-wide HTTP proxies, we
-       * therefore don't use any value this function might return.
-       *
-       * This function is only available on a macOS and is not needed for
-       * IPv4-only builds, hence the conditions above.
-       */
-      CFDictionaryRef dict = SCDynamicStoreCopyProxies(NULL);
-      if(dict)
-        CFRelease(dict);
-    }
-#endif
-
 #ifndef USE_RESOLVE_ON_IPS
     /* First check if this is an IPv4 address string */
     if(Curl_inet_pton(AF_INET, hostname, &in) > 0)

diff --git a/lib/macos.c b/lib/macos.c
@@ -0,0 +1,60 @@
+/***************************************************************************
+ *                                  _   _ ____  _
+ *  Project                     ___| | | |  _ \| |
+ *                             / __| | | | |_) | |
+ *                            | (__| |_| |  _ <| |___
+ *                             \___|\___/|_| \_\_____|
+ *
+ * Copyright (C) 1998 - 2022, Daniel Stenberg, <daniel@haxx.se>, et al.
+ *
+ * This software is licensed as described in the file COPYING, which
+ * you should have received as part of this distribution. The terms
+ * are also available at https://curl.se/docs/copyright.html.
+ *
+ * You may opt to use, copy, modify, merge, publish, distribute and/or sell
+ * copies of the Software, and permit persons to whom the Software is
+ * furnished to do so, under the terms of the COPYING file.
+ *
+ * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
+ * KIND, either express or implied.
+ *
+ * SPDX-License-Identifier: curl
+ *
+ ***************************************************************************/
+
+#include "curl_setup.h"
+
+#if defined(__APPLE__)
+
+#if defined(TARGET_OS_OSX) && TARGET_OS_OSX
+
+#include <curl/curl.h>
+
+#if defined(ENABLE_IPV6) && defined(CURL_OSX_CALL_COPYPROXIES)
+#include <SystemConfiguration/SCDynamicStoreCopySpecific.h>
+#endif
+
+CURLcode Curl_macos_init(void)
+{
+#if defined(ENABLE_IPV6) && defined(CURL_OSX_CALL_COPYPROXIES)
+  {
+    /*
+     * The automagic conversion from IPv4 literals to IPv6 literals only
+     * works if the SCDynamicStoreCopyProxies system function gets called
+     * first. As Curl currently doesn't support system-wide HTTP proxies, we
+     * therefore don't use any value this function might return.
+     *
+     * This function is only available on a macOS and is not needed for
+     * IPv4-only builds, hence the conditions above.
+     */
+    CFDictionaryRef dict = SCDynamicStoreCopyProxies(NULL);
+    if(dict)
+      CFRelease(dict);
+  }
+#endif
+  return CURLE_OK;
+}
+
+#endif /* TARGET_OS_OSX */
+
+#endif /* __APPLE__ */
diff --git a/lib/macos.h b/lib/macos.h
@@ -0,0 +1,38 @@
+#ifndef HEADER_CURL_MACOS_H
+#define HEADER_CURL_MACOS_H
+/***************************************************************************
+ *                                  _   _ ____  _
+ *  Project                     ___| | | |  _ \| |
+ *                             / __| | | | |_) | |
+ *                            | (__| |_| |  _ <| |___
+ *                             \___|\___/|_| \_\_____|
+ *
+ * Copyright (C) 1998 - 2022, Daniel Stenberg, <daniel@haxx.se>, et al.
+ *
+ * This software is licensed as described in the file COPYING, which
+ * you should have received as part of this distribution. The terms
+ * are also available at https://curl.se/docs/copyright.html.
+ *
+ * You may opt to use, copy, modify, merge, publish, distribute and/or sell
+ * copies of the Software, and permit persons to whom the Software is
+ * furnished to do so, under the terms of the COPYING file.
+ *
+ * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
+ * KIND, either express or implied.
+ *
+ * SPDX-License-Identifier: curl
+ *
+ ***************************************************************************/
+#include "curl_setup.h"
+
+#if defined(__APPLE__) && defined(TARGET_OS_OSX) && TARGET_OS_OSX
+
+CURLcode Curl_macos_init(void);
+
+#else
+
+#define Curl_macos_init() CURLE_OK
+
+#endif
+
+#endif /* HEADER_CURL_MACOS_H */