Patch 1471925 - Weak linking support for OSX

This patch causes several symbols in the socket and posix module to be weakly
linked on OSX and disables usage of ftime on OSX. These changes make it possible
to use a binary build on OSX 10.4 on a 10.3 system.

3 files changed, 98 insertions, 2 deletions

diff --git a/Modules/posixmodule.c b/Modules/posixmodule.c
index 816e3eb8d5..ac74a6741f 100644
--- a/Modules/posixmodule.c
+++ b/Modules/posixmodule.c
@@ -13,6 +13,18 @@
 
 /* See also ../Dos/dosmodule.c */
 
+#ifdef __APPLE__
+   /*
+    * Step 1 of support for weak-linking a number of symbols existing on 
+    * OSX 10.4 and later, see the comment in the #ifdef __APPLE__ block
+    * at the end of this file for more information.
+    */
+#  pragma weak lchown
+#  pragma weak statvfs
+#  pragma weak fstatvfs
+
+#endif /* __APPLE__ */
+
 #define PY_SSIZE_T_CLEAN
 
 #include "Python.h"
@@ -8266,6 +8278,45 @@ INITFUNC(void)
 	PyModule_AddObject(m, "statvfs_result",
 			   (PyObject*) &StatVFSResultType);
 	initialized = 1;
+
+#ifdef __APPLE__
+	/*
+	 * Step 2 of weak-linking support on Mac OS X.
+	 *
+	 * The code below removes functions that are not available on the
+	 * currently active platform. 
+	 *
+	 * This block allow one to use a python binary that was build on
+	 * OSX 10.4 on OSX 10.3, without loosing access to new APIs on 
+	 * OSX 10.4.
+	 */
+#ifdef HAVE_FSTATVFS
+	if (fstatvfs == NULL) {
+		if (PyObject_DelAttrString(m, "fstatvfs") == -1) {
+			return;
+		}
+	}
+#endif /* HAVE_FSTATVFS */
+
+#ifdef HAVE_STATVFS
+	if (statvfs == NULL) {
+		if (PyObject_DelAttrString(m, "statvfs") == -1) {
+			return;
+		}
+	}
+#endif /* HAVE_STATVFS */
+
+# ifdef HAVE_LCHOWN
+	if (lchown == NULL) {
+		if (PyObject_DelAttrString(m, "lchown") == -1) {
+			return;
+		}
+	}
+#endif /* HAVE_LCHOWN */
+
+
+#endif /* __APPLE__ */
+
 }
 
 #ifdef __cplusplus
diff --git a/Modules/socketmodule.c b/Modules/socketmodule.c
index c9dd4a3a39..39a0240c5c 100644
--- a/Modules/socketmodule.c
+++ b/Modules/socketmodule.c
@@ -61,6 +61,15 @@ Local naming conventions:
 
 */
 
+#ifdef __APPLE__
+  /*
+   * inet_aton is not available on OSX 10.3, yet we want to use a binary
+   * that was build on 10.4 or later to work on that release, weak linking
+   * comes to the rescue.
+   */
+# pragma weak inet_aton
+#endif
+
 #include "Python.h"
 #include "structmember.h"
 
@@ -306,6 +315,11 @@ const char *inet_ntop(int af, const void *src, char *dst, socklen_t size);
    older releases don't have */
 #undef HAVE_GETADDRINFO
 #endif
+
+#ifdef HAVE_INET_ATON
+#define USE_INET_ATON_WEAKLINK
+#endif
+
 #endif
 
 /* I know this is a bad practice, but it is the easiest... */
@@ -3333,7 +3347,9 @@ socket_inet_aton(PyObject *self, PyObject *args)
 #endif
 #ifdef HAVE_INET_ATON
 	struct in_addr buf;
-#else
+#endif
+
+#if !defined(HAVE_INET_ATON) || defined(USE_INET_ATON_WEAKLINK)
 	/* Have to use inet_addr() instead */
 	unsigned long packed_addr;
 #endif
@@ -3344,6 +3360,10 @@ socket_inet_aton(PyObject *self, PyObject *args)
 
 
 #ifdef HAVE_INET_ATON
+
+#ifdef USE_INET_ATON_WEAKLINK
+    if (inet_aton != NULL) {
+#endif
 	if (inet_aton(ip_addr, &buf))
 		return PyString_FromStringAndSize((char *)(&buf),
 						  sizeof(buf));
@@ -3352,7 +3372,14 @@ socket_inet_aton(PyObject *self, PyObject *args)
 			"illegal IP address string passed to inet_aton");
 	return NULL;
 
-#else /* ! HAVE_INET_ATON */
+#ifdef USE_INET_ATON_WEAKLINK
+   } else {
+#endif
+
+#endif
+
+#if !defined(HAVE_INET_ATON) || defined(USE_INET_ATON_WEAKLINK)
+
 	/* special-case this address as inet_addr might return INADDR_NONE
 	 * for this */
 	if (strcmp(ip_addr, "255.255.255.255") == 0) {
@@ -3369,6 +3396,11 @@ socket_inet_aton(PyObject *self, PyObject *args)
 	}
 	return PyString_FromStringAndSize((char *) &packed_addr,
 					  sizeof(packed_addr));
+
+#ifdef USE_INET_ATON_WEAKLINK
+   }
+#endif
+
 #endif
 }
 
diff --git a/Modules/timemodule.c b/Modules/timemodule.c
index 08d28a103c..f089ecd8e9 100644
--- a/Modules/timemodule.c
+++ b/Modules/timemodule.c
@@ -5,6 +5,18 @@
 #include "structseq.h"
 #include "timefuncs.h"
 
+#ifdef __APPLE__
+#if defined(HAVE_GETTIMEOFDAY) && defined(HAVE_FTIME)
+  /*
+   * floattime falls back to ftime when getttimeofday fails because the latter
+   * might fail on some platforms. This fallback is unwanted on MacOSX because
+   * that makes it impossible to use a binary build on OSX 10.4 on earlier
+   * releases of the OS. Therefore claim we don't support ftime.
+   */
+# undef HAVE_FTIME
+#endif
+#endif
+
 #include <ctype.h>
 
 #include <sys/types.h>
@@ -842,6 +854,7 @@ floattime(void)
 			return (double)t.tv_sec + t.tv_usec*0.000001;
 #endif /* !GETTIMEOFDAY_NO_TZ */
 	}
+
 #endif /* !HAVE_GETTIMEOFDAY */
 	{
 #if defined(HAVE_FTIME)