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

   1 /* Copyright (C) 1997, 1998, 2000 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 Library General Public License as
   6    published by the Free Software Foundation; either version 2 of the
   7    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    Library General Public License for more details.
  13
  14    You should have received a copy of the GNU Library General Public
  15    License along with the GNU C Library; see the file COPYING.LIB.  If not,
  16    write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  17    Boston, MA 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 <linux/posix_types.h>
  27 #include <kernel-features.h>
  28
  29
  30 extern int __syscall_getgroups(int, __kernel_gid_t *);
  31
  32 #ifdef __NR_getgroups32
  33 extern int __syscall_getgroups32 (int, __kernel_gid32_t *);
  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_getgroups32 */
  40
  41 /* For Linux we must convert the array of groups from the format that the
  42    kernel returns.  */
  43 int
  44 __getgroups (int n, gid_t *groups)
  45 {
  46   if (n < 0)
  47     {
  48       __set_errno (EINVAL);
  49       return -1;
  50     }
  51   else
  52     {
  53 #if __ASSUME_32BITUIDS > 0
  54       return INLINE_SYSCALL (getgroups32, 2, n, groups);
  55 #else
  56       int i, ngids;
  57       __kernel_gid_t kernel_groups[n = MIN (n, __sysconf (_SC_NGROUPS_MAX))];
  58 # ifdef __NR_getgroups32
  59       if (__libc_missing_32bit_uids <= 0)
  60         {
  61           int result;
  62           int saved_errno = errno;
  63
  64           result = INLINE_SYSCALL (getgroups32, 2, n, groups);
  65           if (result == 0 || errno != ENOSYS)
  66             return result;
  67
  68           __set_errno (saved_errno);
  69           __libc_missing_32bit_uids = 1;
  70         }
  71 # endif /* __NR_getgroups32 */
  72
  73       ngids = INLINE_SYSCALL (getgroups, 2, n, kernel_groups);
  74       if (n != 0 && ngids > 0)
  75         for (i = 0; i < ngids; i++)
  76           groups[i] = kernel_groups[i];
  77
  78       return ngids;
  79 #endif
  80     }
  81 }
  82
  83 weak_alias (__getgroups, getgroups)