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

   1 /* Copyright (C) 1997, 1998, 2000, 2001, 2003 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3
   4    The GNU C Library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU Lesser General Public
   6    License as published by the Free Software Foundation; either
   7    version 2.1 of the License, or (at your option) any later version.
   8
   9    The GNU C Library 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 GNU
  12    Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public
  15    License along with the GNU C Library; if not, write to the Free
  16    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  17    02111-1307 USA.  */
  18
  19 #include <errno.h>
  20 #include <unistd.h>
  21 #include <sys/param.h>
  22 #include <sys/types.h>
  23
  24 #include <sysdep.h>
  25 #include <sys/syscall.h>
  26 #include <bp-checks.h>
  27
  28 #include <linux/posix_types.h>
  29 #include <kernel-features.h>
  30
  31
  32 #ifdef __NR_getgroups32
  33 # if __ASSUME_32BITUIDS == 0
  34 /* This variable is shared with all files that need to check for 32bit
  35    uids.  */
  36 extern int __libc_missing_32bit_uids attribute_hidden;
  37 # endif
  38 #endif /* __NR_getgroups32 */
  39
  40 /* For Linux we must convert the array of groups from the format that the
  41    kernel returns.  */
  42 int
  43 __getgroups (int n, gid_t *groups)
  44 {
  45 #if __ASSUME_32BITUIDS > 0
  46   return INLINE_SYSCALL (getgroups32, 2, n, CHECK_N (groups, n));
  47 #else
  48   if (__builtin_expect (n, 1) < 0)
  49     {
  50       __set_errno (EINVAL);
  51       return -1;
  52     }
  53   else
  54     {
  55       int i, ngids;
  56       __kernel_gid_t kernel_groups[n = MIN (n, __sysconf (_SC_NGROUPS_MAX))];
  57 # ifdef __NR_getgroups32
  58       if (__libc_missing_32bit_uids <= 0)
  59         {
  60           int result;
  61           int saved_errno = errno;
  62
  63           result = INLINE_SYSCALL (getgroups32, 2, n, CHECK_N (groups, n));
  64           if (result != -1 || errno != ENOSYS)
  65             return result;
  66
  67           __set_errno (saved_errno);
  68           __libc_missing_32bit_uids = 1;
  69         }
  70 # endif /* __NR_getgroups32 */
  71
  72       ngids = INLINE_SYSCALL (getgroups, 2, n, CHECK_N (kernel_groups, n));
  73       if (n != 0 && ngids > 0)
  74         for (i = 0; i < ngids; i++)
  75           (__ptrvalue (groups))[i] = kernel_groups[i];
  76       return ngids;
  77     }
  78 #endif
  79 }
  80
  81 weak_alias (__getgroups, getgroups)