src/group-list.c

   1 /* group-list.c --Print a list of group IDs or names.
   2    Copyright (C) 1989-2015 Free Software Foundation, Inc.
   3
   4    This program is free software: you can redistribute it and/or modify
   5    it under the terms of the GNU General Public License as published by
   6    the Free Software Foundation, either version 3 of the License, or
   7    (at your option) any later version.
   8
   9    This program 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
  12    GNU General Public License for more details.
  13
  14    You should have received a copy of the GNU General Public License
  15    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  16
  17 /* Written by Arnold Robbins.
  18    Major rewrite by David MacKenzie, djm@gnu.ai.mit.edu.
  19    Extracted from id.c by James Youngman. */
  20
  21 #include <config.h>
  22 #include <stdio.h>
  23 #include <sys/types.h>
  24 #include <pwd.h>
  25 #include <grp.h>
  26
  27 #include "system.h"
  28 #include "error.h"
  29 #include "mgetgroups.h"
  30 #include "quote.h"
  31 #include "group-list.h"
  32
  33
  34 /* Print all of the distinct groups the user is in. */
  35 extern bool
  36 print_group_list (const char *username,
  37                   uid_t ruid, gid_t rgid, gid_t egid,
  38                   bool use_names, char delim)
  39 {
  40   bool ok = true;
  41   struct passwd *pwd = NULL;
  42
  43   if (username)
  44     {
  45       pwd = getpwuid (ruid);
  46       if (pwd == NULL)
  47         ok = false;
  48     }
  49
  50   if (!print_group (rgid, use_names))
  51     ok = false;
  52
  53   if (egid != rgid)
  54     {
  55       putchar (delim);
  56       if (!print_group (egid, use_names))
  57         ok = false;
  58     }
  59
  60   {
  61     gid_t *groups;
  62     int i;
  63
  64     int n_groups = xgetgroups (username, (pwd ? pwd->pw_gid : egid), &groups);
  65     if (n_groups < 0)
  66       {
  67         if (username)
  68           {
  69             error (0, errno, _("failed to get groups for user %s"),
  70                    quote (username));
  71           }
  72         else
  73           {
  74             error (0, errno, _("failed to get groups for the current process"));
  75           }
  76         return false;
  77       }
  78
  79     for (i = 0; i < n_groups; i++)
  80       if (groups[i] != rgid && groups[i] != egid)
  81         {
  82           putchar (delim);
  83           if (!print_group (groups[i], use_names))
  84             ok = false;
  85         }
  86     free (groups);
  87   }
  88   return ok;
  89 }
  90
  91 /* Convert a gid_t to string.  Do not use this function directly.
  92    Instead, use it via the gidtostr macro.
  93    Beware that it returns a pointer to static storage.  */
  94 static char *
  95 gidtostr_ptr (gid_t const *gid)
  96 {
  97   static char buf[INT_BUFSIZE_BOUND (uintmax_t)];
  98   return umaxtostr (*gid, buf);
  99 }
 100 #define gidtostr(g) gidtostr_ptr (&(g))
 101
 102 /* Print the name or value of group ID GID. */
 103 extern bool
 104 print_group (gid_t gid, bool use_name)
 105 {
 106   struct group *grp = NULL;
 107   bool ok = true;
 108
 109   if (use_name)
 110     {
 111       grp = getgrgid (gid);
 112       if (grp == NULL)
 113         {
 114           error (0, 0, _("cannot find name for group ID %lu"),
 115                  (unsigned long int) gid);
 116           ok = false;
 117         }
 118     }
 119
 120   char *s = grp ? grp->gr_name : gidtostr (gid);
 121   fputs (s, stdout);
 122   return ok;
 123 }