Don't use -1 fd and AT_SYMLINK_NOFOLLOW for faccessat()

-1 is not an allowed value for the file descriptor, the only
allowed non-file-descriptor value is AT_FDCWD. So use that
instead.

AT_SYMLINK_NOFOLLOW has a weird semantic: It checks whether
we have the specified access on the symbolic link. It also
is implemented only by glibc on Linux, so it's inherently
non-portable. We should just drop it.

Thanks: James Clarke for debugging these issues
Reported-by: James Clarke <jrtc27@jrtc27.com>

1 files changed, 1 insertions, 1 deletions

diff --git a/apt-pkg/contrib/fileutl.cc b/apt-pkg/contrib/fileutl.cc
index affab956c..e4c40fb4f 100644
--- a/apt-pkg/contrib/fileutl.cc
+++ b/apt-pkg/contrib/fileutl.cc
@@ -2792,7 +2792,7 @@ static std::string APT_NONNULL(1) GetTempDirEnv(char const * const env)	/*{{{*/
 	 stat(tmpdir, &st) != 0 || (st.st_mode & S_IFDIR) == 0) // exists and is directory
       tmpdir = "/tmp";
    else if (geteuid() != 0 && // root can do everything anyway
-	 faccessat(-1, tmpdir, R_OK | W_OK | X_OK, AT_EACCESS | AT_SYMLINK_NOFOLLOW) != 0) // current user has rwx access to directory
+	 faccessat(AT_FDCWD, tmpdir, R_OK | W_OK | X_OK, AT_EACCESS) != 0) // current user has rwx access to directory
       tmpdir = "/tmp";
 
    return string(tmpdir);