1 files changed, 81 insertions, 0 deletions
diff --git a/ports/sysdeps/unix/sysv/linux/generic/dl-origin.c b/ports/sysdeps/unix/sysv/linux/generic/dl-origin.c
new file mode 100644
index 0000000000..4502f15d01
--- /dev/null
+++ b/ports/sysdeps/unix/sysv/linux/generic/dl-origin.c
@@ -0,0 +1,81 @@
+/* Find path of executable.
+   Copyright (C) 1998, 1999, 2000, 2002, 2004 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+   Contributed by Ulrich Drepper <drepper@cygnus.com>, 1998.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library.  If not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#include <assert.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <sys/param.h>
+#include <ldsodefs.h>
+#include <sysdep.h>
+
+#include <dl-dst.h>
+
+/* On Linux >= 2.1 systems which have the dcache implementation we can get
+   the path of the application from the /proc/self/exe symlink.  Try this
+   first and fall back on the generic method if necessary.  */
+
+const char *
+_dl_get_origin (void)
+{
+  char linkval[PATH_MAX];
+  char *result;
+  int len;
+  INTERNAL_SYSCALL_DECL (err);
+
+  len = INTERNAL_SYSCALL (readlinkat, err, 4, AT_FDCWD, "/proc/self/exe",
+                          linkval, sizeof (linkval));
+  if (! INTERNAL_SYSCALL_ERROR_P (len, err) && len > 0 && linkval[0] != '[')
+    {
+      /* We can use this value.  */
+      assert (linkval[0] == '/');
+      while (len > 1 && linkval[len - 1] != '/')
+	--len;
+      result = (char *) malloc (len + 1);
+      if (result == NULL)
+	result = (char *) -1;
+      else if (len == 1)
+	memcpy (result, "/", 2);
+      else
+	*((char *) __mempcpy (result, linkval, len - 1)) = '\0';
+    }
+  else
+    {
+      result = (char *) -1;
+      /* We use the environment variable LD_ORIGIN_PATH.  If it is set make
+	 a copy and strip out trailing slashes.  */
+      if (GLRO(dl_origin_path) != NULL)
+	{
+	  size_t len = strlen (GLRO(dl_origin_path));
+	  result = (char *) malloc (len + 1);
+	  if (result == NULL)
+	    result = (char *) -1;
+	  else
+	    {
+	      char *cp = __mempcpy (result, GLRO(dl_origin_path), len);
+	      while (cp > result + 1 && cp[-1] == '/')
+		--cp;
+	      *cp = '\0';
+	    }
+	}
+    }
+
+  return result;
+}