[PATCH] D53557: [hurd] Make getMainExecutable get the real binary path

[Samuel Thibault via Phabricator via llvm-commits]

sthibaul created this revision.
Herald added subscribers: llvm-commits, kristina.

On GNU/Hurd, llvm-config is returning bogus value, such as:

$ llvm-config-6.0 --includedir
/usr/include

while it should be:
$ llvm-config-6.0 --includedir
/usr/lib/llvm-6.0/include

This is because getMainExecutable does not get the actual installation path. On GNU/Hurd, /proc/self/exe is indeed a symlink to the path that was used to start the program, and not the eventual binary file. Llvm's getMainExecutable thus needs to run realpath over it to get the actual place where llvm was installed (/usr/lib/llvm-6.0/bin/llvm-config), and not /usr/bin/llvm-config-6.0. This will not change the result on Linux, where /proc/self/exe already points to the eventual file.


Repository:
  rL LLVM

https://reviews.llvm.org/D53557

Files:
  lib/Support/Unix/Path.inc


Index: lib/Support/Unix/Path.inc
===================================================================
--- lib/Support/Unix/Path.inc
+++ lib/Support/Unix/Path.inc
@@ -180,8 +180,22 @@
   if (sys::fs::exists(aPath)) {
       // /proc is not always mounted under Linux (chroot for example).
       ssize_t len = readlink(aPath.str().c_str(), exe_path, sizeof(exe_path));
-      if (len >= 0)
-          return std::string(exe_path, len);
+      if (len >= 0) {
+          if (len >= sizeof(exe_path))
+              len = sizeof(exe_path)-1;
+          exe_path[len] = '\0';
+
+#if _POSIX_VERSION >= 200112 || defined(__GLIBC__)
+          char *real_path = realpath(exe_path, NULL);
+          std::string ret = std::string(real_path);
+          free(real_path);
+          return ret;
+#else
+          char real_path[MAXPATHLEN];
+          realpath(exe_path, real_path);
+          return std::string(real_path);
+#endif
+      }
   } else {
       // Fall back to the classical detection.
       if (getprogpath(exe_path, argv0))


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