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glibc  2.9
setfsuid.c
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00001 /* Copyright (C) 1998, 2000, 2003, 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 <sys/types.h>
00021 #include <sys/fsuid.h>
00022 
00023 #include <sysdep.h>
00024 #include <sys/syscall.h>
00025 
00026 #include <linux/posix_types.h>
00027 #include <kernel-features.h>
00028 
00029 #ifdef __NR_setfsuid
00030 
00031 # ifdef __NR_setfsuid32
00032 #  if __ASSUME_32BITUIDS == 0
00033 /* This variable is shared with all files that need to check for 32bit
00034    uids.  */
00035 extern int __libc_missing_32bit_uids attribute_hidden;
00036 #  endif
00037 # endif /* __NR_setfsuid32 */
00038 
00039 int
00040 setfsuid (uid_t uid)
00041 {
00042   INTERNAL_SYSCALL_DECL (err);
00043 # if  __ASSUME_32BITUIDS > 0
00044   /* No error checking. */
00045   return INTERNAL_SYSCALL (setfsuid32, err, 1, uid);
00046 # else
00047 #  ifdef __NR_setfsuid32
00048   if (__libc_missing_32bit_uids <= 0)
00049     {
00050       int result;
00051 
00052       result = INTERNAL_SYSCALL (setfsuid32, err, 1, uid);
00053       if (! INTERNAL_SYSCALL_ERROR_P (result, err)
00054          || INTERNAL_SYSCALL_ERRNO (result, err) != ENOSYS)
00055        return result;
00056 
00057       __libc_missing_32bit_uids = 1;
00058     }
00059 #  endif /* __NR_setfsuid32 */
00060 
00061   if (uid != (uid_t) ((__kernel_uid_t) uid))
00062     {
00063       __set_errno (EINVAL);
00064       return -1;
00065     }
00066 
00067   /* No error checking. */
00068   return INTERNAL_SYSCALL (setfsuid, err, 1, uid);
00069 # endif
00070 }
00071 #endif