posix/id.c

   1 /* Copyright (C) 1991, 1995, 1997 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3
   4    The GNU C Library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU Library General Public License as
   6    published by the Free Software Foundation; either version 2 of the
   7    License, or (at your option) any later version.
   8
   9    The GNU C Library is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12    Library General Public License for more details.
  13
  14    You should have received a copy of the GNU Library General Public
  15    License along with the GNU C Library; see the file COPYING.LIB.  If not,
  16    write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  17    Boston, MA 02111-1307, USA.  */
  18
  19 #include <stdio.h>
  20 #include <unistd.h>
  21 #include <stdlib.h>
  22 #include <grp.h>
  23 #include <pwd.h>
  24 #include <limits.h>
  25 #include <sys/types.h>
  26
  27
  28 static void
  29 print_grpname (id, parens)
  30      gid_t id;
  31      int parens;
  32 {
  33   const struct group *const g = getgrgid (id);
  34   if (g == NULL)
  35     {
  36       if (parens)
  37         return;
  38       else
  39         {
  40           fprintf (stderr, _("Couldn't find name for group %d\n"), id);
  41           exit (EXIT_FAILURE);
  42         }
  43     }
  44
  45   if (parens)
  46     printf ("(%s)", g->gr_name);
  47   else
  48     puts (g->gr_name);
  49 }
  50
  51 static void
  52 print_pwdname (id, parens)
  53      uid_t id;
  54      int parens;
  55 {
  56   const struct passwd *const p = getpwuid (id);
  57   if (p == NULL)
  58     {
  59       if (parens)
  60         return;
  61       else
  62         {
  63           fprintf (stderr, _("Couldn't find name for user %d\n"), (int) id);
  64           exit (EXIT_FAILURE);
  65         }
  66     }
  67
  68   if (parens)
  69     printf ("(%s)", p->pw_name);
  70   else
  71     puts (p->pw_name);
  72 }
  73 \f
  74 int
  75 main (argc, argv)
  76      int argc;
  77      char **argv;
  78 {
  79   int print_gid = 1, print_uid = 1;
  80   int real = 0, name = 0;
  81   int error = 0;
  82   int c;
  83
  84   uid_t ruid = getuid (), euid = geteuid ();
  85   gid_t rgid = getgid (), egid = getegid ();
  86
  87   while ((c = getopt (argc, argv, "gurn")) != -1)
  88     switch (c)
  89       {
  90       default:
  91         error = 1;
  92         break;
  93
  94       case 'g':
  95         print_gid = 1;
  96         print_uid = 0;
  97         break;
  98
  99       case 'u':
 100         print_uid = 1;
 101         print_gid = 0;
 102         break;
 103
 104       case 'r':
 105         real = 1;
 106         break;
 107
 108       case 'n':
 109         name = 1;
 110         break;
 111       }
 112
 113   if (error || argc != optind)
 114     {
 115       fputs (_("Usage: id [-gurn]\n"), stderr);
 116       exit (EXIT_FAILURE);
 117     }
 118
 119   if (print_uid && !print_gid)
 120     {
 121       const uid_t uid = real ? ruid : euid;
 122       if (name)
 123         print_pwdname (uid, 0);
 124       else
 125         printf ("%d\n", (int) uid);
 126     }
 127   else if (print_gid && !print_uid)
 128     {
 129       const gid_t gid = real ? rgid : egid;
 130       if (name)
 131         print_grpname (gid, 0);
 132       else
 133         printf ("%d\n", (int) gid);
 134     }
 135   else
 136     {
 137 #if     NGROUPS_MAX > 0
 138       gid_t groups[NGROUPS_MAX];
 139       int ngroups;
 140       ngroups = getgroups (NGROUPS_MAX, groups);
 141 #endif
 142
 143       printf ("uid=%d", (int) ruid);
 144       print_pwdname (ruid, 1);
 145       printf (" gid=%d", (int) rgid);
 146       print_grpname (rgid, 1);
 147       if (euid != ruid)
 148         {
 149           printf (" euid=%d", (int) euid);
 150           print_pwdname (euid, 1);
 151         }
 152       if (egid != rgid)
 153         {
 154           printf (" egid=%d", (int) egid);
 155           print_grpname (egid, 1);
 156         }
 157
 158 #if     NGROUPS > 0
 159       if (ngroups > 0)
 160         {
 161           size_t i;
 162           printf (" groups=%d", (int) groups[0]);
 163           print_grpname (groups[0], 1);
 164           for (i = 1; i < ngroups; ++i)
 165             {
 166               printf (", %d", (int) groups[i]);
 167               print_grpname (groups[i], 1);
 168             }
 169         }
 170 #endif
 171
 172       putchar ('\n');
 173     }
 174
 175   exit (EXIT_SUCCESS);
 176 }