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

   1 /* Copyright (C) 1997, 1998, 2000, 2001 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 extern int __syscall_getgroups (int, __kernel_gid_t *__unbounded);
  33
  34 #ifdef __NR_getgroups32
  35 extern int __syscall_getgroups32 (int, __kernel_gid32_t *__unbounded);
  36 # if __ASSUME_32BITUIDS == 0
  37 /* This variable is shared with all files that need to check for 32bit
  38    uids.  */
  39 extern int __libc_missing_32bit_uids;
  40 # endif
  41 #endif /* __NR_getgroups32 */
  42
  43 /* For Linux we must convert the array of groups from the format that the
  44    kernel returns.  */
  45 int
  46 __getgroups (int n, gid_t *groups)
  47 {
  48 #if __ASSUME_32BITUIDS > 0
  49   return INLINE_SYSCALL (getgroups32, 2, n, CHECK_N (groups, n));
  50 #else
  51   if (__builtin_expect (n, 1) < 0)
  52     {
  53       __set_errno (EINVAL);
  54       return -1;
  55     }
  56   else
  57     {
  58       int i, ngids;
  59       __kernel_gid_t kernel_groups[n = MIN (n, __sysconf (_SC_NGROUPS_MAX))];
  60 # ifdef __NR_getgroups32
  61       if (__libc_missing_32bit_uids <= 0)
  62         {
  63           int result;
  64           int saved_errno = errno;
  65
  66           result = INLINE_SYSCALL (getgroups32, 2, n, CHECK_N (groups, n));
  67           if (result == 0 || errno != ENOSYS)
  68             return result;
  69
  70           __set_errno (saved_errno);
  71           __libc_missing_32bit_uids = 1;
  72         }
  73 # endif /* __NR_getgroups32 */
  74
  75       ngids = INLINE_SYSCALL (getgroups, 2, n, CHECK_N (kernel_groups, n));
  76       if (n != 0 && ngids > 0)
  77         for (i = 0; i < ngids; i++)
  78           (__ptrvalue (groups))[i] = kernel_groups[i];
  79       return ngids;
  80     }
  81 #endif
  82 }
  83
  84 weak_alias (__getgroups, getgroups)