New program, solely for testing (not installed).

diff --git a/src/setuidgid.c b/src/setuidgid.c
new file mode 100644 (file)
index 0000000..3e4780d
--- /dev/null
+++ b/src/setuidgid.c
@@ -0,0 +1,136 @@
+/* setuidgid - run a command with the UID and GID of a specified user
+   Copyright (C) 2003 Free Software Foundation, Inc.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 2, or (at your option)
+   any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software Foundation,
+   Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
+
+/* Written by Jim Meyering  */
+
+#include <config.h>
+#include <stdio.h>
+#include <sys/types.h>
+#include <pwd.h>
+#include <grp.h>
+
+#include "system.h"
+
+#include "closeout.h"
+#include "error.h"
+#include "long-options.h"
+#include "quote.h"
+
+#define PROGRAM_NAME "setuidgid"
+
+/* I wrote this program from scratch, based on the description of
+   D.J. Bernstein's program: http://cr.yp.to/daemontools/setuidgid.html.  */
+#define AUTHORS "Jim Meyering"
+
+#define FAIL_STATUS 111
+
+char *program_name;
+
+void
+usage (int status)
+{
+  if (status != 0)
+    fprintf (stderr, _("Try `%s --help' for more information.\n"),
+            program_name);
+  else
+    {
+      printf (_("\
+Usage: %s USERNAME COMMAND [ARGUMENT]...\n\
+  or:  %s OPTION\n\
+"),
+             program_name, program_name);
+
+      fputs (_("\
+Drop any supplemental groups, assume the user-ID and group-ID of\n\
+the specified USERNAME, and run COMMAND with any specified ARGUMENTs.\n\
+Exit with status 111 if unable to assume the required UID and GID.\n\
+Otherwise, exit with the exit status of COMMAND.\n\
+This program is useful only when run by root (UID=0).\n\
+\n\
+"), stdout);
+      fputs (HELP_OPTION_DESCRIPTION, stdout);
+      fputs (VERSION_OPTION_DESCRIPTION, stdout);
+      printf (_("\nReport bugs to <%s>.\n"), PACKAGE_BUGREPORT);
+    }
+  exit (status);
+}
+
+int
+main (int argc, char **argv)
+{
+  char const *user_id;
+  struct passwd *pwd;
+
+  initialize_main (&argc, &argv);
+  program_name = argv[0];
+  setlocale (LC_ALL, "");
+  bindtextdomain (PACKAGE, LOCALEDIR);
+  textdomain (PACKAGE);
+
+  atexit (close_stdout);
+
+  parse_long_options (argc, argv, PROGRAM_NAME, GNU_PACKAGE, VERSION,
+                     AUTHORS, usage);
+
+  /* The above handles --help and --version.
+     Since there is no other invocation of getopt, handle `--' here.  */
+  if (argc > 1 && STREQ (argv[1], "--"))
+    {
+      --argc;
+      ++argv;
+    }
+
+  if (argc <= 2)
+    {
+      error (0, 0, _("too few arguments"));
+      usage (FAIL_STATUS);
+    }
+
+  user_id = argv[1];
+  pwd = getpwnam (user_id);
+  if (pwd == NULL)
+    {
+      error (0, errno, _("unknown user-ID: %s"), quote (user_id));
+      exit (FAIL_STATUS);
+    }
+
+  if (setgroups (1, &pwd->pw_gid))
+    {
+      error (0, errno, _("cannot set supplemental group"));
+      exit (FAIL_STATUS);
+    }
+
+  if (setgid (pwd->pw_gid))
+    {
+      error (0, errno, _("cannot set group-ID to %ld"), (long) pwd->pw_gid);
+      exit (FAIL_STATUS);
+    }
+
+  if (setuid (pwd->pw_uid))
+    {
+      error (0, errno, _("cannot set user-ID to %ld"), (long) pwd->pw_uid);
+      exit (FAIL_STATUS);
+    }
+
+  {
+    char **cmd = argv + 2;
+    execvp (*cmd, cmd);
+
+    error (0, errno, "could not run command %s", quote (*cmd));
+    exit (FAIL_STATUS);
+  }
+}