src/getent.c

   1 /*
   2
   3 getent.c -- getent utility simulation
   4 Copyright (c) 2013 Kyle J. McKay.  All rights reserved.
   5
   6 This program is free software; you can redistribute it and/or
   7 modify it under the terms of the GNU General Public License
   8 as published by the Free Software Foundation; either version 2
   9 of the License, or (at your option) any later version.
  10
  11 This program is distributed in the hope that it will be useful,
  12 but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 GNU General Public License for more details.
  15
  16 You should have received a copy of the GNU General Public License
  17 along with this program; if not, write to the Free Software
  18 Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
  19
  20 */
  21
  22 /*
  23   A very simple emulation of getent passwd and getent group.  No other databases
  24   are supported.  Only a single key is supported.
  25
  26   USAGE: getent passwd|group key
  27   Exit code 0 for success (and the /etc/passwd|/etc/group format line is written
  28   to stdout), 1 for bad command, 2 for key not found.
  29   Wrong number of or bad arguments exits with 1.
  30 */
  31
  32 #include <stdlib.h>
  33 #include <stdio.h>
  34 #include <string.h>
  35 #include <sys/types.h>
  36 #include <grp.h>
  37 #include <pwd.h>
  38
  39 int main(int argc, char *argv[])
  40 {
  41   const char *db;
  42   const char *key;
  43   int found = 0;
  44
  45   if (argc != 3)
  46     return 1;
  47
  48   db = argv[1];
  49   key = argv[2];
  50   if (!db || !*db || !key || !*key)
  51     return 1;
  52
  53   if (!strcmp(db, "passwd")) {
  54     struct passwd *pwent = getpwnam(key);
  55     if (pwent) {
  56       found = 1;
  57       printf("%s:%s:%d:%d:%s:%s:%s\n", pwent->pw_name, pwent->pw_passwd,
  58         (int)pwent->pw_uid, (int)pwent->pw_gid, pwent->pw_gecos, pwent->pw_dir,
  59         pwent->pw_shell);
  60     }
  61   } else if (!strcmp(db, "group")) {
  62     struct group *grent = getgrnam(key);
  63     if (grent) {
  64       char **memb = grent->gr_mem;
  65       found = 1;
  66       printf("%s:%s:%d:", grent->gr_name, grent->gr_passwd, grent->gr_gid);
  67       if (memb) {
  68         int first = 1;
  69         for (; *memb; ++memb) {
  70           if (first)
  71             first = 0;
  72           else
  73             putchar(',');
  74           fputs(*memb, stdout);
  75         }
  76       }
  77       putchar('\n');
  78     }
  79   } else {
  80     return 1;
  81   }
  82   return found ? 0 : 2;
  83 }