Line data    Source code

       1             : /* getugroups.c -- return a list of the groups a user is in
       2             : 
       3             :    Copyright (C) 1990, 1991, 1998-2000, 2003-2008 Free Software Foundation.
       4             : 
       5             :    This program is free software: you can redistribute it and/or modify
       6             :    it under the terms of the GNU General Public License as published by
       7             :    the Free Software Foundation; either version 3 of the License, or
       8             :    (at your option) any later version.
       9             : 
      10             :    This program is distributed in the hope that it will be useful,
      11             :    but WITHOUT ANY WARRANTY; without even the implied warranty of
      12             :    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
      13             :    GNU General Public License for more details.
      14             : 
      15             :    You should have received a copy of the GNU General Public License
      16             :    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
      17             : 
      18             : /* Written by David MacKenzie. */
      19             : 
      20             : #include <config.h>
      21             : 
      22             : #include "getugroups.h"
      23             : 
      24             : #include <limits.h>
      25             : #include <stdio.h> /* grp.h on alpha OSF1 V2.0 uses "FILE *". */
      26             : #include <grp.h>
      27             : 
      28             : #include <unistd.h>
      29             : 
      30             : #include <errno.h>
      31             : 
      32             : /* Some old header files might not declare setgrent, getgrent, and endgrent.
      33             :    If you don't have them at all, we can't implement this function.
      34             :    You lose!  */
      35             : struct group *getgrent ();
      36             : 
      37             : #include <string.h>
      38             : 
      39             : #define STREQ(s1, s2) ((strcmp (s1, s2) == 0))
      40             : 
      41             : /* Like `getgroups', but for user USERNAME instead of for the current
      42             :    process.  Store at most MAXCOUNT group IDs in the GROUPLIST array.
      43             :    If GID is not -1, store it first (if possible).  GID should be the
      44             :    group ID (pw_gid) obtained from getpwuid, in case USERNAME is not
      45             :    listed in /etc/groups.  Upon failure, set errno and return -1.
      46             :    Otherwise, return the number of IDs we've written into GROUPLIST.  */
      47             : 
      48             : int
      49           0 : getugroups (int maxcount, GETGROUPS_T *grouplist, char const *username,
      50             :             gid_t gid)
      51             : {
      52           0 :   int count = 0;
      53             : 
      54           0 :   if (gid != (gid_t) -1)
      55             :     {
      56           0 :       if (maxcount != 0)
      57           0 :         grouplist[count] = gid;
      58           0 :       ++count;
      59             :     }
      60             : 
      61           0 :   setgrent ();
      62             :   while (1)
      63           0 :     {
      64             :       char **cp;
      65             :       struct group *grp;
      66             : 
      67           0 :       errno = 0;
      68           0 :       grp = getgrent ();
      69           0 :       if (grp == NULL)
      70           0 :         break;
      71             : 
      72           0 :       for (cp = grp->gr_mem; *cp; ++cp)
      73             :         {
      74             :           int n;
      75             : 
      76           0 :           if ( ! STREQ (username, *cp))
      77           0 :             continue;
      78             : 
      79             :           /* See if this group number is already on the list.  */
      80           0 :           for (n = 0; n < count; ++n)
      81           0 :             if (grouplist && grouplist[n] == grp->gr_gid)
      82           0 :               break;
      83             : 
      84             :           /* If it's a new group number, then try to add it to the list.  */
      85           0 :           if (n == count)
      86             :             {
      87           0 :               if (maxcount != 0)
      88             :                 {
      89           0 :                   if (count >= maxcount)
      90           0 :                     goto done;
      91           0 :                   grouplist[count] = grp->gr_gid;
      92             :                 }
      93           0 :               if (count == INT_MAX)
      94             :                 {
      95           0 :                   errno = EOVERFLOW;
      96           0 :                   goto done;
      97             :                 }
      98           0 :               count++;
      99             :             }
     100             :         }
     101             :     }
     102             : 
     103           0 :   if (errno != 0)
     104           0 :     count = -1;
     105             : 
     106           0 :  done:
     107             :   {
     108           0 :     int saved_errno = errno;
     109           0 :     endgrent ();
     110           0 :     errno = saved_errno;
     111             :   }
     112             : 
     113           0 :   return count;
     114             : }