su: move generic su code to su-common.c

Signed-off-by: Karel Zak <kzak@redhat.com>

1 files changed, 3 insertions, 873 deletions

diff --git a/login-utils/su.c b/login-utils/su.c
index 5aff65b1b..29c10f04b 100644
--- a/login-utils/su.c
+++ b/login-utils/su.c
@@ -1,878 +1,8 @@
-/* su for Linux.  Run a shell with substitute user and group IDs.
-   Copyright (C) 1992-2006 Free Software Foundation, Inc.
-   Copyright (C) 2012 SUSE Linux Products GmbH, Nuernberg
 
-   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.
+#include "su-common.h"
 
-   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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.  */
-
-/* Run a shell with the real and effective UID and GID and groups
-   of USER, default `root'.
-
-   The shell run is taken from USER's password entry, /bin/sh if
-   none is specified there.  If the account has a password, su
-   prompts for a password unless run by a user with real UID 0.
-
-   Does not change the current directory.
-   Sets `HOME' and `SHELL' from the password entry for USER, and if
-   USER is not root, sets `USER' and `LOGNAME' to USER.
-   The subshell is not a login shell.
-
-   If one or more ARGs are given, they are passed as additional
-   arguments to the subshell.
-
-   Does not handle /bin/sh or other shells specially
-   (setting argv[0] to "-su", passing -c only to certain shells, etc.).
-   I don't see the point in doing that, and it's ugly.
-
-   Based on an implemenation by David MacKenzie <djm@gnu.ai.mit.edu>.  */
-
-enum
-{
-  EXIT_CANNOT_INVOKE = 126,
-  EXIT_ENOENT = 127
-};
-
-#include <config.h>
-#include <stdio.h>
-#include <getopt.h>
-#include <sys/types.h>
-#include <pwd.h>
-#include <grp.h>
-#include <security/pam_appl.h>
-#include <security/pam_misc.h>
-#include <signal.h>
-#include <sys/wait.h>
-#include <syslog.h>
-
-#include "err.h"
-
-#include <stdbool.h>
-#include "c.h"
-#include "xalloc.h"
-#include "nls.h"
-#include "pathnames.h"
-#include "env.h"
-
-/* name of the pam configuration files. separate configs for su and su -  */
-#define PAM_SERVICE_NAME "su"
-#define PAM_SERVICE_NAME_L "su-l"
-
-#define is_pam_failure(_rc)	((_rc) != PAM_SUCCESS)
-
-#include "logindefs.h"
-
-/* The shell to run if none is given in the user's passwd entry.  */
-#define DEFAULT_SHELL "/bin/sh"
-
-/* The user to become if none is specified.  */
-#define DEFAULT_USER "root"
-
-#ifndef HAVE_ENVIRON_DECL
-extern char **environ;
-#endif
-
-static void run_shell (char const *, char const *, char **, size_t)
-     __attribute__ ((__noreturn__));
-
-/* If true, pass the `-f' option to the subshell.  */
-static bool fast_startup;
-
-/* If true, simulate a login instead of just starting a shell.  */
-static bool simulate_login;
-
-/* If true, change some environment vars to indicate the user su'd to.  */
-static bool change_environment;
-
-/* If true, then don't call setsid() with a command. */
-int same_session = 0;
-
-static bool _pam_session_opened;
-static bool _pam_cred_established;
-static sig_atomic_t volatile caught_signal = false;
-static pam_handle_t *pamh = NULL;
-
-static struct option const longopts[] =
-{
-  {"command", required_argument, NULL, 'c'},
-  {"session-command", required_argument, NULL, 'C'},
-  {"fast", no_argument, NULL, 'f'},
-  {"login", no_argument, NULL, 'l'},
-  {"preserve-environment", no_argument, NULL, 'p'},
-  {"shell", required_argument, NULL, 's'},
-  {"group", required_argument, NULL, 'g'},
-  {"supp-group", required_argument, NULL, 'G'},
-  {"help", no_argument, 0, 'h'},
-  {"version", no_argument, 0, 'V'},
-  {NULL, 0, NULL, 0}
-};
-
-/* Log the fact that someone has run su to the user given by PW;
-   if SUCCESSFUL is true, they gave the correct password, etc.  */
-
-static void
-log_su (struct passwd const *pw, bool successful)
-{
-  const char *new_user, *old_user, *tty;
-
-  new_user = pw->pw_name;
-  /* The utmp entry (via getlogin) is probably the best way to identify
-     the user, especially if someone su's from a su-shell.  */
-  old_user = getlogin ();
-  if (!old_user)
-    {
-      /* getlogin can fail -- usually due to lack of utmp entry.
-	 Resort to getpwuid.  */
-      struct passwd *pwd = getpwuid (getuid ());
-      old_user = (pwd ? pwd->pw_name : "");
-    }
-  tty = ttyname (STDERR_FILENO);
-  if (!tty)
-    tty = "none";
-
-  openlog (program_invocation_short_name, 0 , LOG_AUTH);
-  syslog (LOG_NOTICE, "%s(to %s) %s on %s",
-	  successful ? "" : "FAILED SU ",
-	  new_user, old_user, tty);
-  closelog ();
-}
-
-static struct pam_conv conv =
-{
-  misc_conv,
-  NULL
-};
-
-static void
-cleanup_pam (int retcode)
-{
-  int saved_errno = errno;
-
-  if (_pam_session_opened)
-    pam_close_session (pamh, 0);
-
-  if (_pam_cred_established)
-    pam_setcred (pamh, PAM_DELETE_CRED | PAM_SILENT);
-
-  pam_end(pamh, retcode);
-
-  errno = saved_errno;
-}
-
-/* Signal handler for parent process.  */
-static void
-su_catch_sig (int sig __attribute__((__unused__)))
-{
-  caught_signal = true;
-}
-
-/* Export env variables declared by PAM modules.  */
-static void
-export_pamenv (void)
-{
-  char **env;
-
-  /* This is a copy but don't care to free as we exec later anyways.  */
-  env = pam_getenvlist (pamh);
-  while (env && *env)
-    {
-      if (putenv (*env) != 0)
-	err (EXIT_FAILURE, NULL);
-      env++;
-    }
-}
-
-static void
-create_watching_parent (void)
-{
-  pid_t child;
-  sigset_t ourset;
-  int status = 0;
-  int retval;
-
-  retval = pam_open_session (pamh, 0);
-  if (is_pam_failure(retval))
-    {
-      cleanup_pam (retval);
-      errx (EXIT_FAILURE, _("cannot not open session: %s"),
-	     pam_strerror (pamh, retval));
-    }
-  else
-    _pam_session_opened = 1;
-
-  child = fork ();
-  if (child == (pid_t) -1)
-    {
-      cleanup_pam (PAM_ABORT);
-      err (EXIT_FAILURE, _("cannot create child process"));
-    }
-
-  /* the child proceeds to run the shell */
-  if (child == 0)
-    return;
-
-  /* In the parent watch the child.  */
-
-  /* su without pam support does not have a helper that keeps
-     sitting on any directory so let's go to /.  */
-  if (chdir ("/") != 0)
-    warn (_("cannot change directory to %s"), "/");
-
-  sigfillset (&ourset);
-  if (sigprocmask (SIG_BLOCK, &ourset, NULL))
-    {
-      warn (_("cannot block signals"));
-      caught_signal = true;
-    }
-  if (!caught_signal)
-    {
-      struct sigaction action;
-      action.sa_handler = su_catch_sig;
-      sigemptyset (&action.sa_mask);
-      action.sa_flags = 0;
-      sigemptyset (&ourset);
-    if (!same_session)
-      {
-        if (sigaddset(&ourset, SIGINT) || sigaddset(&ourset, SIGQUIT))
-          {
-            warn (_("cannot set signal handler"));
-            caught_signal = true;
-          }
-      }
-    if (!caught_signal && (sigaddset(&ourset, SIGTERM)
-                    || sigaddset(&ourset, SIGALRM)
-                    || sigaction(SIGTERM, &action, NULL)
-                    || sigprocmask(SIG_UNBLOCK, &ourset, NULL))) {
-	  warn (_("cannot set signal handler"));
-	  caught_signal = true;
-	}
-    if (!caught_signal && !same_session && (sigaction(SIGINT, &action, NULL)
-                                     || sigaction(SIGQUIT, &action, NULL)))
-      {
-        warn (_("cannot set signal handler"));
-        caught_signal = true;
-      }
-    }
-  if (!caught_signal)
-    {
-      pid_t pid;
-      for (;;)
-	{
-	  pid = waitpid (child, &status, WUNTRACED);
-
-	  if (pid != (pid_t)-1 && WIFSTOPPED (status))
-	    {
-	      kill (getpid (), SIGSTOP);
-	      /* once we get here, we must have resumed */
-	      kill (pid, SIGCONT);
-	    }
-	  else
-	    break;
-	}
-      if (pid != (pid_t)-1)
-	if (WIFSIGNALED (status))
-	  status = WTERMSIG (status) + 128;
-	else
-	  status = WEXITSTATUS (status);
-      else
-	status = 1;
-    }
-  else
-    status = 1;
-
-  if (caught_signal)
-    {
-      fprintf (stderr, _("\nSession terminated, killing shell..."));
-      kill (child, SIGTERM);
-    }
-
-  cleanup_pam (PAM_SUCCESS);
-
-  if (caught_signal)
-    {
-      sleep (2);
-      kill (child, SIGKILL);
-      fprintf (stderr, _(" ...killed.\n"));
-    }
-  exit (status);
-}
-
-static void
-authenticate (const struct passwd *pw)
-{
-  const struct passwd *lpw;
-  const char *cp;
-  int retval;
-
-  retval = pam_start (simulate_login ? PAM_SERVICE_NAME_L : PAM_SERVICE_NAME,
-		      pw->pw_name, &conv, &pamh);
-  if (is_pam_failure(retval))
-    goto done;
-
-  if (isatty (0) && (cp = ttyname (0)) != NULL)
-    {
-      const char *tty;
-
-      if (strncmp (cp, "/dev/", 5) == 0)
-	tty = cp + 5;
-      else
-	tty = cp;
-      retval = pam_set_item (pamh, PAM_TTY, tty);
-      if (is_pam_failure(retval))
-	goto done;
-    }
-
-  lpw = getpwuid (getuid ());
-  if (lpw && lpw->pw_name)
-    {
-      retval = pam_set_item (pamh, PAM_RUSER, (const void *) lpw->pw_name);
-      if (is_pam_failure(retval))
-	goto done;
-    }
-
-  retval = pam_authenticate (pamh, 0);
-  if (is_pam_failure(retval))
-    goto done;
-
-  retval = pam_acct_mgmt (pamh, 0);
-  if (retval == PAM_NEW_AUTHTOK_REQD)
-    {
-      /* Password has expired.  Offer option to change it.  */
-      retval = pam_chauthtok (pamh, PAM_CHANGE_EXPIRED_AUTHTOK);
-    }
-
-done:
-
-  log_su (pw, !is_pam_failure(retval));
-
-  if (is_pam_failure(retval))
-    {
-      const char *msg = pam_strerror(pamh, retval);
-      pam_end(pamh, retval);
-      sleep (getlogindefs_num ("FAIL_DELAY", 1));
-      errx (EXIT_FAILURE, "%s", msg?msg:_("incorrect password"));
-    }
-}
-
-/* Add or clear /sbin and /usr/sbin for the su command
-   used without `-'.  */
-
-/* Set if /sbin is found in path.  */
-#define SBIN_MASK	0x01
-/* Set if /usr/sbin is found in path.  */
-#define USBIN_MASK	0x02
-
-static char *
-addsbin (const char *const path)
-{
-  unsigned char smask = 0;
-  char *ptr, *tmp, *cur, *ret = NULL;
-  size_t len;
-
-  if (!path || *path == 0)
-    return NULL;
-
-  tmp = xstrdup (path);
-  cur = tmp;
-  for (ptr = strsep (&cur, ":"); ptr != NULL; ptr = strsep (&cur, ":"))
-    {
-      if (!strcmp (ptr, "/sbin"))
-	smask |= SBIN_MASK;
-      if (!strcmp (ptr, "/usr/sbin"))
-	smask |= USBIN_MASK;
-    }
-
-  if ((smask & (USBIN_MASK|SBIN_MASK)) == (USBIN_MASK|SBIN_MASK))
-    {
-      free (tmp);
-      return NULL;
-    }
-
-  len = strlen (path);
-  if (!(smask & USBIN_MASK))
-    len += strlen ("/usr/sbin:");
-
-  if (!(smask & SBIN_MASK))
-    len += strlen (":/sbin");
-
-  ret = xmalloc (len + 1);
-  strcpy (tmp, path);
-
-  *ret = 0;
-  cur = tmp;
-  for (ptr = strsep (&cur, ":"); ptr; ptr = strsep (&cur, ":"))
-    {
-      if (!strcmp (ptr, "."))
-	continue;
-      if (*ret)
-	strcat (ret, ":");
-      if (!(smask & USBIN_MASK) && !strcmp (ptr, "/bin"))
-	{
-	  strcat (ret, "/usr/sbin:");
-	  strcat (ret, ptr);
-	  smask |= USBIN_MASK;
-	  continue;
-	}
-      if (!(smask & SBIN_MASK) && !strcmp (ptr, "/usr/bin"))
-	{
-	  strcat (ret, ptr);
-	  strcat (ret, ":/sbin");
-	  smask |= SBIN_MASK;
-	  continue;
-	}
-      strcat (ret, ptr);
-    }
-  free (tmp);
-
-  if (!(smask & USBIN_MASK))
-    strcat (ret, ":/usr/sbin");
-
-  if (!(smask & SBIN_MASK))
-    strcat (ret, ":/sbin");
-
-  return ret;
-}
-
-static char *
-clearsbin (const char *const path)
-{
-  char *ptr, *tmp, *cur, *ret = NULL;
-
-  if (!path || *path == 0)
-    return NULL;
-
-  tmp = xstrdup (path);
-
-  ret = xmalloc (strlen (path) + 1);
-  *ret = 0;
-  cur = tmp;
-  for (ptr = strsep (&cur, ":"); ptr; ptr = strsep (&cur, ":"))
-    {
-      if (!strcmp (ptr, "/sbin"))
-	continue;
-      if (!strcmp (ptr, "/usr/sbin"))
-	continue;
-      if (!strcmp (ptr, "/usr/local/sbin"))
-	continue;
-      if (*ret)
-	strcat (ret, ":");
-      strcat (ret, ptr);
-    }
-  free (tmp);
-
-  return ret;
-}
-
-static void
-set_path(const struct passwd* pw)
-{
-  int r;
-  if (pw->pw_uid)
-    r = logindefs_setenv("PATH", "ENV_PATH", _PATH_DEFPATH);
-
-  else if ((r = logindefs_setenv("PATH", "ENV_ROOTPATH", NULL)) != 0)
-    r = logindefs_setenv("PATH", "ENV_SUPATH", _PATH_DEFPATH_ROOT);
-
-  if (r != 0)
-    err (EXIT_FAILURE,  _("failed to set PATH"));
-}
-
-/* Update `environ' for the new shell based on PW, with SHELL being
-   the value for the SHELL environment variable.  */
-
-static void
-modify_environment (const struct passwd *pw, const char *shell)
-{
-  if (simulate_login)
-    {
-      /* Leave TERM unchanged.  Set HOME, SHELL, USER, LOGNAME, PATH.
-         Unset all other environment variables.  */
-      char const *term = getenv ("TERM");
-      if (term)
-	term = xstrdup (term);
-      environ = xmalloc ((6 + !!term) * sizeof (char *));
-      environ[0] = NULL;
-      if (term)
-	xsetenv ("TERM", term, 1);
-      xsetenv ("HOME", pw->pw_dir, 1);
-      xsetenv ("SHELL", shell, 1);
-      xsetenv ("USER", pw->pw_name, 1);
-      xsetenv ("LOGNAME", pw->pw_name, 1);
-      set_path(pw);
-    }
-  else
-    {
-      /* Set HOME, SHELL, and if not becoming a super-user,
-	 USER and LOGNAME.  */
-      if (change_environment)
-        {
-          xsetenv ("HOME", pw->pw_dir, 1);
-          xsetenv ("SHELL", shell, 1);
-	  if (getlogindefs_bool ("ALWAYS_SET_PATH", 0))
-	    set_path(pw);
-	  else
-	    {
-	      char const *path = getenv ("PATH");
-	      char *new = NULL;
-
-	      if (pw->pw_uid)
-		new = clearsbin (path);
-	      else
-		new = addsbin (path);
-
-	      if (new)
-		{
-		  xsetenv ("PATH", new, 1);
-		  free (new);
-		}
-	    }
-          if (pw->pw_uid)
-            {
-              xsetenv ("USER", pw->pw_name, 1);
-              xsetenv ("LOGNAME", pw->pw_name, 1);
-            }
-        }
-    }
-
-  export_pamenv ();
-}
-
-/* Become the user and group(s) specified by PW.  */
-
-static void
-init_groups (const struct passwd *pw, gid_t *groups, int num_groups)
-{
-  int retval;
-
-  errno = 0;
-
-  if (num_groups)
-    retval = setgroups (num_groups, groups);
-  else
-    retval = initgroups (pw->pw_name, pw->pw_gid);
-
-  if (retval == -1)
-    {
-      cleanup_pam (PAM_ABORT);
-      err (EXIT_FAILURE, _("cannot set groups"));
-    }
-  endgrent ();
-
-  retval = pam_setcred (pamh, PAM_ESTABLISH_CRED);
-  if (is_pam_failure(retval))
-    errx (EXIT_FAILURE, "%s", pam_strerror (pamh, retval));
-  else
-    _pam_cred_established = 1;
-}
-
-static void
-change_identity (const struct passwd *pw)
-{
-  if (setgid (pw->pw_gid))
-    err (EXIT_FAILURE,  _("cannot set group id"));
-  if (setuid (pw->pw_uid))
-    err (EXIT_FAILURE,  _("cannot set user id"));
-}
-
-/* Run SHELL, or DEFAULT_SHELL if SHELL is empty.
-   If COMMAND is nonzero, pass it to the shell with the -c option.
-   Pass ADDITIONAL_ARGS to the shell as more arguments; there
-   are N_ADDITIONAL_ARGS extra arguments.  */
-
-static void
-run_shell (char const *shell, char const *command, char **additional_args,
-	   size_t n_additional_args)
-{
-  size_t n_args = 1 + fast_startup + 2 * !!command + n_additional_args + 1;
-  char const **args = xcalloc (n_args, sizeof *args);
-  size_t argno = 1;
-
-  if (simulate_login)
-    {
-      char *arg0;
-      char *shell_basename;
-
-      shell_basename = basename (shell);
-      arg0 = xmalloc (strlen (shell_basename) + 2);
-      arg0[0] = '-';
-      strcpy (arg0 + 1, shell_basename);
-      args[0] = arg0;
-    }
-  else
-    args[0] = basename (shell);
-  if (fast_startup)
-    args[argno++] = "-f";
-  if (command)
-    {
-      args[argno++] = "-c";
-      args[argno++] = command;
-    }
-  memcpy (args + argno, additional_args, n_additional_args * sizeof *args);
-  args[argno + n_additional_args] = NULL;
-  execv (shell, (char **) args);
-
-  {
-    int exit_status = (errno == ENOENT ? EXIT_ENOENT : EXIT_CANNOT_INVOKE);
-    warn ("%s", shell);
-    exit (exit_status);
-  }
-}
-
-/* Return true if SHELL is a restricted shell (one not returned by
-   getusershell), else false, meaning it is a standard shell.  */
-
-static bool
-restricted_shell (const char *shell)
-{
-  char *line;
-
-  setusershell ();
-  while ((line = getusershell ()) != NULL)
-    {
-      if (*line != '#' && !strcmp (line, shell))
-	{
-	  endusershell ();
-	  return false;
-	}
-    }
-  endusershell ();
-  return true;
-}
-
-static void __attribute__((__noreturn__))
-usage (int status)
-{
-  if (status != EXIT_SUCCESS)
-    fprintf (stderr, _("Try `%s --help' for more information.\n"),
-	     program_invocation_short_name);
-  else
-    {
-      fputs(USAGE_HEADER, stdout);
-      printf (_(" %s [options] [-] [USER [arg]...]\n"), program_invocation_short_name);
-      fputs (_("\n\
- Change the effective user id and group id to that of USER.\n\
- A mere - implies -l.   If USER not given, assume root.\n"), stdout);
-      fputs(USAGE_OPTIONS, stdout);
-      fputs (_("\
- -, -l, --login               make the shell a login shell\n\
- -c, --command <command>      pass a single command to the shell with -c\n\
- --session-command <command>  pass a single command to the shell with -c\n\
-                              and do not create a new session\n\
- -g --group=group             specify the primary group\n\
- -G --supp-group=group        specify a supplemental group\n\
- -f, --fast                   pass -f to the shell (for csh or tcsh)\n\
- -m, --preserve-environment   do not reset environment variables\n\
- -p                           same as -m\n\
- -s, --shell <shell>          run shell if /etc/shells allows it\n\
-"), stdout);
-
-      fputs(USAGE_SEPARATOR, stdout);
-      fputs(USAGE_HELP, stdout);
-      fputs(USAGE_VERSION, stdout);
-      printf(USAGE_MAN_TAIL("su(1)"));
-    }
-  exit (status);
-}
-
-static
-void load_config(void)
-{
-  logindefs_load_file("/etc/default/su");
-  logindefs_load_file(_PATH_LOGINDEFS);
-}
-
-/*
- * Returns 1 if the current user is not root
- */
-static int
-evaluate_uid(void)
-{
-  uid_t ruid = getuid();
-  uid_t euid = geteuid();
-
-  /* if we're really root and aren't running setuid */
-  return (uid_t) 0 == ruid && ruid == euid ? 0 : 1;
-}
-
-int
-main (int argc, char **argv)
+int main(int argv, char **argc)
 {
-  int optc;
-  const char *new_user = DEFAULT_USER;
-  char *command = NULL;
-  int request_same_session = 0;
-  char *shell = NULL;
-  struct passwd *pw;
-  struct passwd pw_copy;
-  struct group *gr;
-  gid_t groups[NGROUPS_MAX];
-  int num_supp_groups = 0;
-  int use_gid = 0;
-  int restricted;
-
-  setlocale (LC_ALL, "");
-  bindtextdomain (PACKAGE, LOCALEDIR);
-  textdomain (PACKAGE);
-
-  fast_startup = false;
-  simulate_login = false;
-  change_environment = true;
-
-  while ((optc = getopt_long (argc, argv, "c:fg:G:lmps:hV", longopts, NULL)) != -1)
-    {
-      switch (optc)
-	{
-	case 'c':
-	  command = optarg;
-	  break;
-
-        case 'C':
-          command = optarg;
-          request_same_session = 1;
-          break;
-
-	case 'f':
-	  fast_startup = true;
-	  break;
-
-	case 'g':
-	  gr = getgrnam(optarg);
-	  if (!gr)
-	    errx(EXIT_FAILURE, _("group %s does not exist"), optarg);
-	  use_gid = 1;
-	  groups[0] = gr->gr_gid;
-	  break;
-
-	case 'G':
-	  num_supp_groups++;
-	  if (num_supp_groups >= NGROUPS_MAX)
-	     errx(EXIT_FAILURE,
-		  _("can't specify more than %d supplemental groups"),
-		  NGROUPS_MAX - 1);
-	  gr = getgrnam(optarg);
-	  if (!gr)
-	    errx(EXIT_FAILURE, _("group %s does not exist"), optarg);
-	  groups[num_supp_groups] = gr->gr_gid;
-	  break;
-
-	case 'l':
-	  simulate_login = true;
-	  break;
-
-	case 'm':
-	case 'p':
-	  change_environment = false;
-	  break;
-
-	case 's':
-	  shell = optarg;
-	  break;
-
-	case 'h':
-	  usage(0);
-
-	case 'V':
-	  printf(UTIL_LINUX_VERSION);
-	  exit(EXIT_SUCCESS);
-
-	default:
-	  usage (EXIT_FAILURE);
-	}
-    }
-
-  restricted = evaluate_uid ();
-
-  if (optind < argc && !strcmp (argv[optind], "-"))
-    {
-      simulate_login = true;
-      ++optind;
-    }
-  if (optind < argc)
-    new_user = argv[optind++];
-
-  if ((num_supp_groups || use_gid) && restricted)
-    errx(EXIT_FAILURE, _("only root can specify alternative groups"));
-
-  logindefs_load_defaults = load_config;
-
-  pw = getpwnam (new_user);
-  if (! (pw && pw->pw_name && pw->pw_name[0] && pw->pw_dir && pw->pw_dir[0]
-	 && pw->pw_passwd))
-    errx (EXIT_FAILURE, _("user %s does not exist"), new_user);
-
-  /* Make a copy of the password information and point pw at the local
-     copy instead.  Otherwise, some systems (e.g. Linux) would clobber
-     the static data through the getlogin call from log_su.
-     Also, make sure pw->pw_shell is a nonempty string.
-     It may be NULL when NEW_USER is a username that is retrieved via NIS (YP),
-     but that doesn't have a default shell listed.  */
-  pw_copy = *pw;
-  pw = &pw_copy;
-  pw->pw_name = xstrdup (pw->pw_name);
-  pw->pw_passwd = xstrdup (pw->pw_passwd);
-  pw->pw_dir = xstrdup (pw->pw_dir);
-  pw->pw_shell = xstrdup (pw->pw_shell && pw->pw_shell[0]
-			  ? pw->pw_shell
-			  : DEFAULT_SHELL);
-  endpwent ();
-
-  if (num_supp_groups && !use_gid)
-  {
-    pw->pw_gid = groups[1];
-    memmove (groups, groups + 1, sizeof(gid_t) * num_supp_groups);
-  }
-  else if (use_gid)
-  {
-    pw->pw_gid = groups[0];
-    num_supp_groups++;
-  }
-
-  authenticate (pw);
-
-  if (request_same_session || !command || !pw->pw_uid)
-    same_session = 1;
-
-  if (!shell && !change_environment)
-    shell = getenv ("SHELL");
-  if (shell && getuid () != 0 && restricted_shell (pw->pw_shell))
-    {
-      /* The user being su'd to has a nonstandard shell, and so is
-	 probably a uucp account or has restricted access.  Don't
-	 compromise the account by allowing access with a standard
-	 shell.  */
-      warnx (_("using restricted shell %s"), pw->pw_shell);
-      shell = NULL;
-    }
-  shell = xstrdup (shell ? shell : pw->pw_shell);
-
-  init_groups (pw, groups, num_supp_groups);
-
-  create_watching_parent ();
-  /* Now we're in the child.  */
-
-  change_identity (pw);
-  if (!same_session)
-    setsid ();
-
-  /* Set environment after pam_open_session, which may put KRB5CCNAME
-     into the pam_env, etc.  */
-
-  modify_environment (pw, shell);
-
-  if (simulate_login && chdir (pw->pw_dir) != 0)
-    warn (_("warning: cannot change directory to %s"), pw->pw_dir);
-
-  run_shell (shell, command, argv + optind, max (0, argc - optind));
+	return su_main(argv, argc, SU_MODE);
 }
 
-// vim: sw=2 cinoptions=>4,n-2,{2,^-2,\:2,=2,g0,h2,p5,t0,+2,(0,u0,w1,m1