src/group-list.c

   1 /* group-list.c --Print a list of group IDs or names.
   2    Copyright (C) 1989-2018 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 <https://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
  63     int n_groups = xgetgroups (username, (pwd ? pwd->pw_gid : egid), &groups);
  64     if (n_groups < 0)
  65       {
  66         if (username)
  67           {
  68             error (0, errno, _("failed to get groups for user %s"),
  69                    quote (username));
  70           }
  71         else
  72           {
  73             error (0, errno, _("failed to get groups for the current process"));
  74           }
  75         return false;
  76       }
  77
  78     for (int i = 0; i < n_groups; i++)
  79       if (groups[i] != rgid && groups[i] != egid)
  80         {
  81           putchar (delim);
  82           if (!print_group (groups[i], use_names))
  83             ok = false;
  84         }
  85     free (groups);
  86   }
  87   return ok;
  88 }
  89
  90 /* Convert a gid_t to string.  Do not use this function directly.
  91    Instead, use it via the gidtostr macro.
  92    Beware that it returns a pointer to static storage.  */
  93 static char *
  94 gidtostr_ptr (gid_t const *gid)
  95 {
  96   static char buf[INT_BUFSIZE_BOUND (uintmax_t)];
  97   return umaxtostr (*gid, buf);
  98 }
  99 #define gidtostr(g) gidtostr_ptr (&(g))
 100
 101 /* Print the name or value of group ID GID. */
 102 extern bool
 103 print_group (gid_t gid, bool use_name)
 104 {
 105   struct group *grp = NULL;
 106   bool ok = true;
 107
 108   if (use_name)
 109     {
 110       grp = getgrgid (gid);
 111       if (grp == NULL)
 112         {
 113           error (0, 0, _("cannot find name for group ID %lu"),
 114                  (unsigned long int) gid);
 115           ok = false;
 116         }
 117     }
 118
 119   char *s = grp ? grp->gr_name : gidtostr (gid);
 120   fputs (s, stdout);
 121   return ok;
 122 }