sysdeps/unix/sysv/linux/i386/setgroups.c

   1 /* Copyright (C) 1997,1998,2000,2002,2004,2006,2011
   2    Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library 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 GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, see
  17    <http://www.gnu.org/licenses/>.  */
  18
  19 #include <errno.h>
  20 #include <grp.h>
  21 #include <unistd.h>
  22 #include <sys/types.h>
  23
  24 #include <sysdep.h>
  25 #include <sys/syscall.h>
  26 #include <bp-checks.h>
  27
  28 #include <setxid.h>
  29 #include <linux/posix_types.h>
  30 #include <kernel-features.h>
  31
  32
  33 #ifdef __NR_setgroups32
  34 # if __ASSUME_32BITUIDS == 0
  35 /* This variable is shared with all files that need to check for 32bit
  36    uids.  */
  37 extern int __libc_missing_32bit_uids;
  38 # endif
  39 #endif /* __NR_setgroups32 */
  40
  41 /* Set the group set for the current user to GROUPS (N of them).  For
  42    Linux we must convert the array of groups into the format that the
  43    kernel expects.  */
  44 int
  45 setgroups (size_t n, const gid_t *groups)
  46 {
  47 #if __ASSUME_32BITUIDS > 0
  48   return INLINE_SETXID_SYSCALL (setgroups32, 2, n, CHECK_N (groups, n));
  49 #else
  50   if (n > (size_t) __sysconf (_SC_NGROUPS_MAX))
  51     {
  52       __set_errno (EINVAL);
  53       return -1;
  54     }
  55   else
  56     {
  57       size_t i;
  58       __kernel_gid_t kernel_groups[n];
  59
  60 # ifdef __NR_setgroups32
  61       if (__libc_missing_32bit_uids <= 0)
  62         {
  63           int result;
  64           int saved_errno = errno;
  65
  66           result = INLINE_SETXID_SYSCALL (setgroups32, 2, n,
  67                                           CHECK_N (groups, n));
  68           if (result == 0 || errno != ENOSYS)
  69             return result;
  70
  71           __set_errno (saved_errno);
  72           __libc_missing_32bit_uids = 1;
  73         }
  74 # endif /* __NR_setgroups32 */
  75       for (i = 0; i < n; i++)
  76         {
  77           kernel_groups[i] = (__ptrvalue (groups))[i];
  78           if (groups[i] != (gid_t) ((__kernel_gid_t) groups[i]))
  79             {
  80               __set_errno (EINVAL);
  81               return -1;
  82             }
  83         }
  84
  85       return INLINE_SETXID_SYSCALL (setgroups, 2, n,
  86                                     CHECK_N (kernel_groups, n));
  87     }
  88 #endif
  89 }
  90 libc_hidden_def (setgroups)