sysdeps/unix/sysv/linux/mips/pread.c

   1 /* Copyright (C) 1997, 1998, 2000, 2002, 2003, 2004
   2    Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4    Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997.
   5
   6    The GNU C Library is free software; you can redistribute it and/or
   7    modify it under the terms of the GNU Lesser General Public
   8    License as published by the Free Software Foundation; either
   9    version 2.1 of the License, or (at your option) any later version.
  10
  11    The GNU C Library is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14    Lesser General Public License for more details.
  15
  16    You should have received a copy of the GNU Lesser General Public
  17    License along with the GNU C Library.  If not, see
  18    <http://www.gnu.org/licenses/>.  */
  19
  20 #include <assert.h>
  21 #include <errno.h>
  22 #ifndef NO_SGIDEFS_H
  23 #include <sgidefs.h>
  24 #endif
  25 #include <unistd.h>
  26 #include <endian.h>
  27
  28 #include <sysdep-cancel.h>
  29 #include <sys/syscall.h>
  30 #include <bp-checks.h>
  31
  32 #include <kernel-features.h>
  33
  34 #ifdef __NR_pread64             /* Newer kernels renamed but it's the same.  */
  35 # ifdef __NR_pread
  36 #  error "__NR_pread and __NR_pread64 both defined???"
  37 # endif
  38 # define __NR_pread __NR_pread64
  39 #endif
  40
  41 #if defined __NR_pread || __ASSUME_PREAD_SYSCALL > 0
  42
  43 # if __ASSUME_PREAD_SYSCALL == 0
  44 static ssize_t __emulate_pread (int fd, void *buf, size_t count,
  45                                 off_t offset) internal_function;
  46 # endif
  47
  48 ssize_t
  49 __libc_pread (fd, buf, count, offset)
  50      int fd;
  51      void *buf;
  52      size_t count;
  53      off_t offset;
  54 {
  55   ssize_t result;
  56
  57 #if _MIPS_SIM != _ABI64
  58   assert (sizeof (offset) == 4);
  59 #endif
  60
  61   if (SINGLE_THREAD_P)
  62     {
  63       /* First try the syscall.  */
  64 #if _MIPS_SIM == _ABIN32 || _MIPS_SIM == _ABI64
  65       result = INLINE_SYSCALL (pread, 4, fd, CHECK_N (buf, count), count,
  66                                offset);
  67 #else
  68       result = INLINE_SYSCALL (pread, 6, fd, CHECK_N (buf, count), count, 0,
  69                                __LONG_LONG_PAIR (offset >> 31, offset));
  70 #endif
  71 # if __ASSUME_PREAD_SYSCALL == 0
  72       if (result == -1 && errno == ENOSYS)
  73         /* No system call available.  Use the emulation.  */
  74         result = __emulate_pread (fd, buf, count, offset);
  75 # endif
  76       return result;
  77     }
  78
  79   int oldtype = LIBC_CANCEL_ASYNC ();
  80
  81   /* First try the syscall.  */
  82 #if _MIPS_SIM == _ABIN32 || _MIPS_SIM == _ABI64
  83   result = INLINE_SYSCALL (pread, 4, fd, CHECK_N (buf, count), count, offset);
  84 #else
  85   result = INLINE_SYSCALL (pread, 6, fd, CHECK_N (buf, count), count, 0,
  86                            __LONG_LONG_PAIR (offset >> 31, offset));
  87 #endif
  88 # if __ASSUME_PREAD_SYSCALL == 0
  89   if (result == -1 && errno == ENOSYS)
  90     /* No system call available.  Use the emulation.  */
  91     result = __emulate_pread (fd, buf, count, offset);
  92 # endif
  93
  94   LIBC_CANCEL_RESET (oldtype);
  95
  96   return result;
  97 }
  98
  99 strong_alias (__libc_pread, __pread)
 100 weak_alias (__libc_pread, pread)
 101
 102 # define __libc_pread(fd, buf, count, offset) \
 103      static internal_function __emulate_pread (fd, buf, count, offset)
 104 #endif
 105
 106 #if __ASSUME_PREAD_SYSCALL == 0
 107 # include <sysdeps/posix/pread.c>
 108 #endif