src/group-list.c

   1 /* group-list.c --Print a list of group IDs or names.
   2    Copyright (C) 1989-2024 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 "mgetgroups.h"
  29 #include "quote.h"
  30 #include "group-list.h"
  31
  32
  33 /* Print all of the distinct groups the user is in. */
  34 extern bool
  35 print_group_list (char const *username,
  36                   uid_t ruid, gid_t rgid, gid_t egid,
  37                   bool use_names, char delim)
  38 {
  39   bool ok = true;
  40   struct passwd *pwd = nullptr;
  41
  42   if (username)
  43     {
  44       pwd = getpwuid (ruid);
  45       if (pwd == nullptr)
  46         ok = false;
  47     }
  48
  49   if (!print_group (rgid, use_names))
  50     ok = false;
  51
  52   if (egid != rgid)
  53     {
  54       putchar (delim);
  55       if (!print_group (egid, use_names))
  56         ok = false;
  57     }
  58
  59   {
  60     gid_t *groups;
  61
  62     int n_groups = xgetgroups (username, (pwd ? pwd->pw_gid : egid), &groups);
  63     if (n_groups < 0)
  64       {
  65         if (username)
  66           {
  67             error (0, errno, _("failed to get groups for user %s"),
  68                    quote (username));
  69           }
  70         else
  71           {
  72             error (0, errno, _("failed to get groups for the current process"));
  73           }
  74         return false;
  75       }
  76
  77     for (int i = 0; i < n_groups; i++)
  78       if (groups[i] != rgid && groups[i] != egid)
  79         {
  80           putchar (delim);
  81           if (!print_group (groups[i], use_names))
  82             ok = false;
  83         }
  84     free (groups);
  85   }
  86   return ok;
  87 }
  88
  89 /* Convert a gid_t to string.  Do not use this function directly.
  90    Instead, use it via the gidtostr macro.
  91    Beware that it returns a pointer to static storage.  */
  92 static char *
  93 gidtostr_ptr (gid_t const *gid)
  94 {
  95   static char buf[INT_BUFSIZE_BOUND (uintmax_t)];
  96   return umaxtostr (*gid, buf);
  97 }
  98 #define gidtostr(g) gidtostr_ptr (&(g))
  99
 100 /* Print the name or value of group ID GID. */
 101 extern bool
 102 print_group (gid_t gid, bool use_name)
 103 {
 104   struct group *grp = nullptr;
 105   bool ok = true;
 106
 107   if (use_name)
 108     {
 109       grp = getgrgid (gid);
 110       if (grp == nullptr)
 111         {
 112           if (TYPE_SIGNED (gid_t))
 113             {
 114               intmax_t g = gid;
 115               error (0, 0, _("cannot find name for group ID %jd"), g);
 116             }
 117           else
 118             {
 119               uintmax_t g = gid;
 120               error (0, 0, _("cannot find name for group ID %ju"), g);
 121             }
 122           ok = false;
 123         }
 124     }
 125
 126   char *s = grp ? grp->gr_name : gidtostr (gid);
 127   fputs (s, stdout);
 128   return ok;
 129 }