From 893a0f9f0e8f816c7fb0eb4cfcc972e7e3c68731 Mon Sep 17 00:00:00 2001
From: Chris Lattner <sabre@nondot.org>
Date: Mon, 2 Mar 2009 22:17:15 +0000
Subject: [PATCH] Fix main executable path name resolution on FreeBSD, patch by
 Ed Schouten!

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@65882 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/System/Unix/Path.inc | 61 +++++++++++++++++++++++++++++++++++++++-
 1 file changed, 60 insertions(+), 1 deletion(-)

diff --git a/lib/System/Unix/Path.inc b/lib/System/Unix/Path.inc
index 3a651f957cd..4a6b5051998 100644
--- a/lib/System/Unix/Path.inc
+++ b/lib/System/Unix/Path.inc
@@ -266,10 +266,69 @@ Path::GetCurrentDirectory() {
   return Path(pathname);
 }
 
+#ifdef __FreeBSD__
+static int
+test_dir(char buf[PATH_MAX], char ret[PATH_MAX],
+    const char *dir, const char *bin)
+{
+	struct stat sb;
+
+	snprintf(buf, PATH_MAX, "%s//%s", dir, bin);
+	if (realpath(buf, ret) == NULL)
+		return (1);
+	if (stat(buf, &sb) != 0)
+		return (1);
+	
+	return (0);
+}
+
+static char *
+getprogpath(char ret[PATH_MAX], const char *bin)
+{
+	char *pv, *s, *t, buf[PATH_MAX];
+
+	/* First approach: absolute path. */
+	if (bin[0] == '/') {
+		if (test_dir(buf, ret, "/", bin) == 0)
+			return (ret);
+		return (NULL);
+	}
+
+	/* Second approach: relative path. */
+	if (strchr(bin, '/') != NULL) {
+		if (getcwd(buf, PATH_MAX) == NULL)
+			return (NULL);
+		if (test_dir(buf, ret, buf, bin) == 0)
+			return (ret);
+		return (NULL);
+	}
+
+	/* Third approach: $PATH */
+	if ((pv = getenv("PATH")) == NULL)
+		return (NULL);
+	s = pv = strdup(pv);
+	if (pv == NULL)
+		return (NULL);
+	while ((t = strsep(&s, ":")) != NULL) {
+		if (test_dir(buf, ret, t, bin) == 0) {
+			free(pv);
+			return (ret);
+		}
+	}
+	free(pv);
+	return (NULL);
+}
+#endif
+
 /// GetMainExecutable - Return the path to the main executable, given the
 /// value of argv[0] from program startup.
 Path Path::GetMainExecutable(const char *argv0, void *MainAddr) {
-#if defined(__linux__) || defined(__CYGWIN__)
+#if defined(__FreeBSD__)
+  char exe_path[PATH_MAX];
+
+  if (getprogpath(exe_path, argv0) != NULL)
+    return Path(std::string(exe_path));
+#elif defined(__linux__) || defined(__CYGWIN__)
   char exe_path[MAXPATHLEN];
   ssize_t len = readlink("/proc/self/exe", exe_path, sizeof(exe_path));
   if (len > 0 && len < MAXPATHLEN - 1) {
-- 
2.34.1