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

   1 /* Copyright (C) 2000,2002-2004,2006,2009,2010 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, see
  16    <http://www.gnu.org/licenses/>.  */
  17
  18 #include <assert.h>
  19 #include <errno.h>
  20 #include <sysdep-cancel.h>      /* Must come before <fcntl.h>.  */
  21 #include <fcntl.h>
  22 #include <stdarg.h>
  23
  24 #include <sys/syscall.h>
  25 #include <kernel-features.h>
  26
  27 #ifndef __ASSUME_FCNTL64
  28 /* This variable is shared with all files that check for fcntl64.  */
  29 int __have_no_fcntl64;
  30 #endif
  31
  32 #ifdef __ASSUME_F_GETOWN_EX
  33 # define miss_F_GETOWN_EX 0
  34 #elif !defined __ASSUME_FCNTL64
  35 static int miss_F_GETOWN_EX;
  36 #endif
  37
  38
  39 #if defined NO_CANCELLATION && !defined __ASSUME_FCNTL64
  40 # define __fcntl_nocancel  __libc_fcntl
  41 #endif
  42
  43 #if !defined NO_CANCELLATION || !defined __ASSUME_FCNTL64
  44 int
  45 __fcntl_nocancel (int fd, int cmd, ...)
  46 {
  47   va_list ap;
  48   void *arg;
  49
  50   va_start (ap, cmd);
  51   arg = va_arg (ap, void *);
  52   va_end (ap);
  53
  54 #ifndef __ASSUME_FCNTL64
  55 # ifdef __NR_fcntl64
  56   if (! __have_no_fcntl64)
  57     {
  58       int result = INLINE_SYSCALL (fcntl64, 3, fd, cmd, arg);
  59       if (result >= 0 || errno != ENOSYS)
  60         return result;
  61
  62       __have_no_fcntl64 = 1;
  63     }
  64 # endif
  65   switch (cmd)
  66     {
  67     case F_GETLK64:
  68       /* Convert arg from flock64 to flock and back.  */
  69       {
  70         struct flock fl;
  71         struct flock64 *fl64 = arg;
  72         int res;
  73
  74         fl.l_start = (off_t)fl64->l_start;
  75         /* Check if we can represent the values with the smaller type.  */
  76         if ((off64_t) fl.l_start != fl64->l_start)
  77           {
  78           eoverflow:
  79             __set_errno (EOVERFLOW);
  80             return -1;
  81           }
  82         fl.l_len = (off_t) fl64->l_len;
  83         /* Check if we can represent the values with the smaller type.  */
  84         if ((off64_t) fl.l_len != fl64->l_len)
  85           goto eoverflow;
  86
  87         fl.l_type = fl64->l_type;
  88         fl.l_whence = fl64->l_whence;
  89         fl.l_pid = fl64->l_pid;
  90
  91         res = INLINE_SYSCALL (fcntl, 3, fd, F_GETLK, &fl);
  92         if (res  != 0)
  93           return res;
  94         /* Everything ok, convert back.  */
  95         fl64->l_type = fl.l_type;
  96         fl64->l_whence = fl.l_whence;
  97         fl64->l_start = fl.l_start;
  98         fl64->l_len = fl.l_len;
  99         fl64->l_pid = fl.l_pid;
 100
 101         return 0;
 102       }
 103     case F_SETLK64:
 104     case F_SETLKW64:
 105       /* Try to convert arg from flock64 to flock.  */
 106       {
 107         struct flock fl;
 108         struct flock64 *fl64 = arg;
 109
 110         fl.l_start = (off_t) fl64->l_start;
 111         /* Check if we can represent the values with the smaller type.  */
 112         if ((off64_t) fl.l_start != fl64->l_start)
 113           goto eoverflow;
 114
 115         fl.l_len = (off_t)fl64->l_len;
 116         /* Check if we can represent the values with the smaller type.  */
 117         if ((off64_t) fl.l_len != fl64->l_len)
 118           {
 119             __set_errno (EOVERFLOW);
 120             return -1;
 121           }
 122         fl.l_type = fl64->l_type;
 123         fl.l_whence = fl64->l_whence;
 124         fl.l_pid = fl64->l_pid;
 125         assert (F_SETLK - F_SETLKW == F_SETLK64 - F_SETLKW64);
 126         return INLINE_SYSCALL (fcntl, 3, fd, cmd + F_SETLK - F_SETLK64, &fl);
 127       }
 128     case F_GETOWN:
 129       if (! miss_F_GETOWN_EX)
 130         {
 131           INTERNAL_SYSCALL_DECL (err);
 132           struct f_owner_ex fex;
 133           int res = INTERNAL_SYSCALL (fcntl, err, 3, fd, F_GETOWN_EX, &fex);
 134           if (!INTERNAL_SYSCALL_ERROR_P (res, err))
 135             return fex.type == F_OWNER_GID ? -fex.pid : fex.pid;
 136
 137 # ifndef __ASSUME_F_GETOWN_EX
 138           if (INTERNAL_SYSCALL_ERRNO (res, err) == EINVAL)
 139             miss_F_GETOWN_EX = 1;
 140           else
 141 # endif
 142             {
 143               __set_errno (INTERNAL_SYSCALL_ERRNO (res, err));
 144               return -1;
 145             }
 146         }
 147       /* FALLTHROUGH */
 148     default:
 149       return INLINE_SYSCALL (fcntl, 3, fd, cmd, arg);
 150     }
 151   return -1;
 152 #else
 153   return INLINE_SYSCALL (fcntl64, 3, fd, cmd, arg);
 154 #endif  /* !__ASSUME_FCNTL64  */
 155 }
 156 #endif /* NO_CANCELLATION || !__ASSUME_FCNTL64 */
 157
 158
 159 #ifndef __fcntl_nocancel
 160 int
 161 __libc_fcntl (int fd, int cmd, ...)
 162 {
 163   va_list ap;
 164   void *arg;
 165
 166   va_start (ap, cmd);
 167   arg = va_arg (ap, void *);
 168   va_end (ap);
 169
 170 # ifdef __ASSUME_FCNTL64
 171   if (SINGLE_THREAD_P || (cmd != F_SETLKW && cmd != F_SETLKW64))
 172     return INLINE_SYSCALL (fcntl64, 3, fd, cmd, arg);
 173
 174   int oldtype = LIBC_CANCEL_ASYNC ();
 175
 176   int result = INLINE_SYSCALL (fcntl64, 3, fd, cmd, arg);
 177 # else
 178   if (SINGLE_THREAD_P || (cmd != F_SETLKW && cmd != F_SETLKW64))
 179     return __fcntl_nocancel (fd, cmd, arg);
 180
 181   int oldtype = LIBC_CANCEL_ASYNC ();
 182
 183   int result = __fcntl_nocancel (fd, cmd, arg);
 184 # endif
 185
 186   LIBC_CANCEL_RESET (oldtype);
 187
 188   return result;
 189 }
 190 #endif
 191 libc_hidden_def (__libc_fcntl)
 192
 193 weak_alias (__libc_fcntl, __fcntl)
 194 libc_hidden_weak (__fcntl)
 195 weak_alias (__libc_fcntl, fcntl)