sysdeps/unix/sysv/linux/fcntl.c

   1 /* Copyright (C) 2000-2014 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
  28 #ifdef __ASSUME_F_GETOWN_EX
  29 # define miss_F_GETOWN_EX 0
  30 #else
  31 static int miss_F_GETOWN_EX;
  32 #endif
  33
  34
  35 static int
  36 do_fcntl (int fd, int cmd, void *arg)
  37 {
  38   if (cmd != F_GETOWN || miss_F_GETOWN_EX)
  39     return INLINE_SYSCALL (fcntl, 3, fd, cmd, arg);
  40
  41   INTERNAL_SYSCALL_DECL (err);
  42   struct f_owner_ex fex;
  43   int res = INTERNAL_SYSCALL (fcntl, err, 3, fd, F_GETOWN_EX, &fex);
  44   if (!INTERNAL_SYSCALL_ERROR_P (res, err))
  45     return fex.type == F_OWNER_GID ? -fex.pid : fex.pid;
  46
  47 #ifndef __ASSUME_F_GETOWN_EX
  48   if (INTERNAL_SYSCALL_ERRNO (res, err) == EINVAL)
  49     {
  50       res = INLINE_SYSCALL (fcntl, 3, fd, F_GETOWN, arg);
  51       miss_F_GETOWN_EX = 1;
  52       return res;
  53     }
  54 #endif
  55
  56   __set_errno (INTERNAL_SYSCALL_ERRNO (res, err));
  57   return -1;
  58 }
  59
  60
  61 #ifndef NO_CANCELLATION
  62 int
  63 __fcntl_nocancel (int fd, int cmd, ...)
  64 {
  65   va_list ap;
  66   void *arg;
  67
  68   va_start (ap, cmd);
  69   arg = va_arg (ap, void *);
  70   va_end (ap);
  71
  72   return do_fcntl (fd, cmd, arg);
  73 }
  74 #endif
  75
  76
  77 int
  78 __libc_fcntl (int fd, int cmd, ...)
  79 {
  80   va_list ap;
  81   void *arg;
  82
  83   va_start (ap, cmd);
  84   arg = va_arg (ap, void *);
  85   va_end (ap);
  86
  87   if (SINGLE_THREAD_P || cmd != F_SETLKW)
  88     return do_fcntl (fd, cmd, arg);
  89
  90   int oldtype = LIBC_CANCEL_ASYNC ();
  91
  92   int result = do_fcntl (fd, cmd, arg);
  93
  94   LIBC_CANCEL_RESET (oldtype);
  95
  96   return result;
  97 }
  98 libc_hidden_def (__libc_fcntl)
  99
 100 weak_alias (__libc_fcntl, __fcntl)
 101 libc_hidden_weak (__fcntl)
 102 weak_alias (__libc_fcntl, fcntl)