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glibc  2.9
setgroups.c
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00001 /* Copyright (C) 1997,1998,2000,2002,2004,2006 Free Software Foundation, Inc.
00002    This file is part of the GNU C Library.
00003 
00004    The GNU C Library is free software; you can redistribute it and/or
00005    modify it under the terms of the GNU Lesser General Public
00006    License as published by the Free Software Foundation; either
00007    version 2.1 of the License, or (at your option) any later version.
00008 
00009    The GNU C Library is distributed in the hope that it will be useful,
00010    but WITHOUT ANY WARRANTY; without even the implied warranty of
00011    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00012    Lesser General Public License for more details.
00013 
00014    You should have received a copy of the GNU Lesser General Public
00015    License along with the GNU C Library; if not, write to the Free
00016    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
00017    02111-1307 USA.  */
00018 
00019 #include <errno.h>
00020 #include <grp.h>
00021 #include <unistd.h>
00022 #include <sys/types.h>
00023 
00024 #include <sysdep.h>
00025 #include <sys/syscall.h>
00026 #include <bp-checks.h>
00027 
00028 #include <linux/posix_types.h>
00029 #include <kernel-features.h>
00030 
00031 
00032 #ifdef __NR_setgroups32
00033 # if __ASSUME_32BITUIDS == 0
00034 /* This variable is shared with all files that need to check for 32bit
00035    uids.  */
00036 extern int __libc_missing_32bit_uids;
00037 # endif
00038 #endif /* __NR_setgroups32 */
00039 
00040 /* Set the group set for the current user to GROUPS (N of them).  For
00041    Linux we must convert the array of groups into the format that the
00042    kernel expects.  */
00043 int
00044 setgroups (size_t n, const gid_t *groups)
00045 {
00046 #if __ASSUME_32BITUIDS > 0
00047   return INLINE_SYSCALL (setgroups32, 2, n, CHECK_N (groups, n));
00048 #else
00049   if (n > (size_t) __sysconf (_SC_NGROUPS_MAX))
00050     {
00051       __set_errno (EINVAL);
00052       return -1;
00053     }
00054   else
00055     {
00056       size_t i;
00057       __kernel_gid_t kernel_groups[n];
00058 
00059 # ifdef __NR_setgroups32
00060       if (__libc_missing_32bit_uids <= 0)
00061        {
00062          int result;
00063          int saved_errno = errno;
00064 
00065          result = INLINE_SYSCALL (setgroups32, 2, n, CHECK_N (groups, n));
00066          if (result == 0 || errno != ENOSYS)
00067            return result;
00068 
00069          __set_errno (saved_errno);
00070          __libc_missing_32bit_uids = 1;
00071        }
00072 # endif /* __NR_setgroups32 */
00073       for (i = 0; i < n; i++)
00074        {
00075          kernel_groups[i] = (__ptrvalue (groups))[i];
00076          if (groups[i] != (gid_t) ((__kernel_gid_t) groups[i]))
00077            {
00078              __set_errno (EINVAL);
00079              return -1;
00080            }
00081        }
00082 
00083       return INLINE_SYSCALL (setgroups, 2, n, CHECK_N (kernel_groups, n));
00084     }
00085 #endif
00086 }
00087 libc_hidden_def (setgroups)