[libglnx] libcontainer: Search $PATH for exec() if argv[0] is not absolute

[Colin Walters <walters src gnome org>]

commit 91875459cdc9e61c2ea8c5831c7593ec7641fd2b
Author: Colin Walters <walters verbum org>
Date:   Mon Jun 15 12:27:30 2015 -0400

    libcontainer: Search $PATH for exec() if argv[0] is not absolute
    
    In Fedora rawhide, dracut switched from `/usr/sbin` to `/usr/bin`,
    which broke rpm-ostree's hardcoding of the path.
    
    There was no real reason to hardcode it (assume our `$PATH` is sane
    and secure), so in order to help support that, this change in libglnx
    will automatically search $PATH if the input is not absolute.
    
    (This is a sane default for a process spawning library IMO)

 glnx-libcontainer.c |   12 ++++++++++--
 1 files changed, 10 insertions(+), 2 deletions(-)
---
diff --git a/glnx-libcontainer.c b/glnx-libcontainer.c
index dafd8ad..49fa095 100644
--- a/glnx-libcontainer.c
+++ b/glnx-libcontainer.c
@@ -242,8 +242,16 @@ glnx_libcontainer_run_in_root (const char  *dest,
   if (chdir ("/") != 0)
     _perror_fatal ("chdir: ");
 
-  if (execv (binary, argv) != 0)
-    _perror_fatal ("execl: ");
+  if (binary[0] == '/')
+    {
+      if (execv (binary, argv) != 0)
+        _perror_fatal ("execv: ");
+    }
+  else
+    {
+      if (execvp (binary, argv) != 0)
+        _perror_fatal ("execvp: ");
+    }
 
   g_assert_not_reached ();
 }