Avoid linking problem in sys_reset_uid_gid

* lib/system.h (sys_reset_uid_gid) [!MSDOS]: On failure, instead
of invoking FATAL_ERROR set errno and return the name of the
syscall that failed, so that the caller can decide what to do.
This avoids some GNU Tar linking problems on compilers that do not
inline this function.  All callers changed.

2 files changed, 13 insertions, 17 deletions

diff --git a/lib/rtapelib.c b/lib/rtapelib.c
index fae0db8..0c516e5 100644
--- a/lib/rtapelib.c
+++ b/lib/rtapelib.c
@@ -504,7 +504,10 @@ rmt_open__ (const char *file_name, int open_mode, int bias,
 	  error (EXIT_ON_EXEC_ERROR, errno,
 		 _("Cannot redirect files for remote shell"));
 
-	sys_reset_uid_gid ();
+	char const *reseterr = sys_reset_uid_gid ();
+	if (reseterr)
+	  error (EXIT_ON_EXEC_ERROR, errno,
+		 _("Cannot reset uid and gid: %s"), reseterr);
 
 	if (remote_user)
 	  execl (remote_shell, remote_shell_basename, remote_host,
diff --git a/lib/system.h b/lib/system.h
index 1bd5ba9..6acefd7 100644
--- a/lib/system.h
+++ b/lib/system.h
@@ -470,29 +470,22 @@ char *getenv ();
 # define SET_BINARY_MODE(arc)
 # define TTY_NAME "/dev/tty"
 # include <paxlib.h>
-static inline void
+static inline char const *
 sys_reset_uid_gid (void)
 {
-  struct passwd *pw;
   uid_t uid = getuid ();
   gid_t gid = getgid ();
+  struct passwd *pw = getpwuid (uid);
 
-  if ((pw = getpwuid (uid)) == NULL)
-    {
-      FATAL_ERROR ((0, errno, "%s(%lu)", "getpwuid", (unsigned long)uid));
-    }
-  if (initgroups (pw->pw_name, getgid ()))
-    {
-      FATAL_ERROR ((0, errno, "%s", "initgroups"));
-    }
+  if (!pw)
+    return "getpwuid";
+  if (initgroups (pw->pw_name, gid))
+    return "initgroups";
   if (gid != getegid () && setgid (gid) && errno != EPERM)
-    {
-      FATAL_ERROR ((0, errno, "%s", "setgid"));
-    }
+    return "setgid";
   if (uid != geteuid () && setuid (uid) && errno != EPERM)
-    {
-      FATAL_ERROR ((0, errno, "%s", "setuid"));
-    }
+    return "setuid";
+  return NULL;
 }
 #endif