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

   1 /* Copyright (C) 1998,1999,2000,2002,2003,2004 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
  22 #include <sysdep.h>
  23 #include <sys/syscall.h>
  24 #include <shlib-compat.h>
  25 #include <bp-checks.h>
  26
  27 #include <linux/posix_types.h>
  28 #include "kernel-features.h"
  29
  30 /*
  31   In Linux 2.1.x the chown functions have been changed.  A new function lchown
  32   was introduced.  The new chown now follows symlinks - the old chown and the
  33   new lchown do not follow symlinks.
  34   The new lchown function has the same number as the old chown had and the
  35   new chown has a new number.  When compiling with headers from Linux > 2.1.8x
  36   it's impossible to run this libc with older kernels.  In these cases libc
  37   has therefore to route calls to chown to the old chown function.
  38 */
  39
  40 extern int __chown_is_lchown (const char *__file, uid_t __owner,
  41                               gid_t __group);
  42 extern int __real_chown (const char *__file, uid_t __owner, gid_t __group);
  43
  44
  45 #if defined __NR_lchown || __ASSUME_LCHOWN_SYSCALL > 0
  46 /* Running under Linux > 2.1.80.  */
  47
  48 # ifdef __NR_chown32
  49 #  if __ASSUME_32BITUIDS == 0
  50 /* This variable is shared with all files that need to check for 32bit
  51    uids.  */
  52 extern int __libc_missing_32bit_uids;
  53 #  endif
  54 # endif /* __NR_chown32 */
  55
  56 int
  57 __real_chown (const char *file, uid_t owner, gid_t group)
  58 {
  59 # if __ASSUME_LCHOWN_SYSCALL == 0
  60   static int __libc_old_chown;
  61   int result;
  62
  63   if (!__libc_old_chown)
  64     {
  65       int saved_errno = errno;
  66 #  ifdef __NR_chown32
  67       if (__libc_missing_32bit_uids <= 0)
  68         {
  69           int result;
  70           int saved_errno = errno;
  71
  72           result = INLINE_SYSCALL (chown32, 3, CHECK_STRING (file), owner, group);
  73           if (result == 0 || errno != ENOSYS)
  74             return result;
  75
  76           __set_errno (saved_errno);
  77           __libc_missing_32bit_uids = 1;
  78         }
  79 #  endif /* __NR_chown32 */
  80       if (((owner + 1) > (uid_t) ((__kernel_uid_t) -1U))
  81           || ((group + 1) > (gid_t) ((__kernel_gid_t) -1U)))
  82         {
  83           __set_errno (EINVAL);
  84           return -1;
  85         }
  86
  87       result = INLINE_SYSCALL (chown, 3, CHECK_STRING (file), owner, group);
  88
  89       if (result >= 0 || errno != ENOSYS)
  90         return result;
  91
  92       __set_errno (saved_errno);
  93       __libc_old_chown = 1;
  94     }
  95
  96   return __lchown (file, owner, group);
  97 # elif __ASSUME_32BITUIDS
  98   /* This implies __ASSUME_LCHOWN_SYSCALL.  */
  99   return INLINE_SYSCALL (chown32, 3, CHECK_STRING (file), owner, group);
 100 # else
 101   /* !__ASSUME_32BITUIDS && ASSUME_LCHOWN_SYSCALL  */
 102 #  ifdef __NR_chown32
 103   if (__libc_missing_32bit_uids <= 0)
 104     {
 105       int result;
 106       int saved_errno = errno;
 107
 108       result = INLINE_SYSCALL (chown32, 3, CHECK_STRING (file), owner, group);
 109       if (result == 0 || errno != ENOSYS)
 110         return result;
 111
 112       __set_errno (saved_errno);
 113       __libc_missing_32bit_uids = 1;
 114     }
 115 #  endif /* __NR_chown32 */
 116   if (((owner + 1) > (uid_t) ((__kernel_uid_t) -1U))
 117       || ((group + 1) > (gid_t) ((__kernel_gid_t) -1U)))
 118     {
 119       __set_errno (EINVAL);
 120       return -1;
 121     }
 122
 123   return INLINE_SYSCALL (chown, 3, CHECK_STRING (file), owner, group);
 124 # endif
 125 }
 126 #endif
 127
 128
 129 #if !defined __NR_lchown && __ASSUME_LCHOWN_SYSCALL == 0
 130 /* Compiling under older kernels.  */
 131 int
 132 __chown_is_lchown (const char *file, uid_t owner, gid_t group)
 133 {
 134   return INLINE_SYSCALL (chown, 3, CHECK_STRING (file), owner, group);
 135 }
 136 #elif SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_1)
 137 /* Compiling for compatibiity.  */
 138 int
 139 attribute_compat_text_section
 140 __chown_is_lchown (const char *file, uid_t owner, gid_t group)
 141 {
 142   return __lchown (file, owner, group);
 143 }
 144 #endif
 145
 146 #if SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_1)
 147 compat_symbol (libc, __chown_is_lchown, chown, GLIBC_2_0);
 148 #endif
 149
 150 #ifdef __NR_lchown
 151 versioned_symbol (libc, __real_chown, chown, GLIBC_2_1);
 152 strong_alias (__real_chown, __chown)
 153 #else
 154 strong_alias (__chown_is_lchown, __chown_is_lchown21)
 155 versioned_symbol (libc, __chown_is_lchown21, chown, GLIBC_2_1);
 156 strong_alias (__chown_is_lchown, __chown)
 157 #endif
 158 libc_hidden_def (__chown)