[PATCH] util: Try finding out application name using dladdr if available

[fsateler@xxxxxxxxxx (Felipe Sateler)]

This fixes getting the binary name in the Hurd, or any other port using
the GNU C library, but only in the case where the library is directly
linked to. Opening with dlopen will not work.

Change in v3: reorder header includes and definitions
Change in v2: use a weak reference to main, so that we
don't crash when main cannot be found.
---
 configure.ac     |  2 ++
 src/pulse/util.c | 23 +++++++++++++++++++++++
 2 files changed, 25 insertions(+)

diff --git a/configure.ac b/configure.ac
index f13ddb0..74bea71 100644
--- a/configure.ac
+++ b/configure.ac
@@ -580,6 +580,8 @@ AC_SYS_LARGEFILE
 # Check for open64 to know if the current system does have open64() and similar functions
 AC_CHECK_FUNCS_ONCE([open64])
 
+AC_SEARCH_LIBS([dladdr], [dl], [HAVE_DLADDR=1], [HAVE_DLADDR=0])
+AC_DEFINE(HAVE_DLADDR, [1], [Have dladdr?])
 
 ###################################
 #      External libraries         #
diff --git a/src/pulse/util.c b/src/pulse/util.c
index ace698c..bc1ef8d 100644
--- a/src/pulse/util.c
+++ b/src/pulse/util.c
@@ -33,6 +33,15 @@
 #include <unistd.h>
 #include <sys/types.h>
 
+#if defined(HAVE_DLADDR) && defined(PA_GCC_WEAKREF)
+#ifndef _GNU_SOURCE
+#define _GNU_SOURCE 1
+#endif
+#include <dlfcn.h>
+
+static int _main() PA_GCC_WEAKREF(main);
+#endif
+
 #ifdef HAVE_PWD_H
 #include <pwd.h>
 #endif
@@ -218,6 +227,20 @@ char *pa_get_binary_name(char *s, size_t l) {
     }
 #endif
 
+#if defined(HAVE_DLADDR) && defined(PA_GCC_WEAKREF)
+    {
+        Dl_info info;
+        if(_main) {
+            int err = dladdr(&_main, &info);
+            if (err != 0) {
+                char *p = pa_realpath(info.dli_fname);
+                if (p)
+                    return p;
+            }
+        }
+    }
+#endif
+
 #if defined(HAVE_SYS_PRCTL_H) && defined(PR_GET_NAME)
     {
 
-- 
2.1.1