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, write to the Free
  18    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  19    02111-1307 USA.  */
  20
  21 #include <assert.h>
  22 #include <errno.h>
  23 #ifndef NO_SGIDEFS_H
  24 #include <sgidefs.h>
  25 #endif
  26 #include <unistd.h>
  27 #include <endian.h>
  28
  29 #include <sysdep-cancel.h>
  30 #include <sys/syscall.h>
  31 #include <bp-checks.h>
  32
  33 #include <kernel-features.h>
  34
  35 #ifdef __NR_pread64             /* Newer kernels renamed but it's the same.  */
  36 # ifdef __NR_pread
  37 #  error "__NR_pread and __NR_pread64 both defined???"
  38 # endif
  39 # define __NR_pread __NR_pread64
  40 #endif
  41
  42 #if defined __NR_pread || __ASSUME_PREAD_SYSCALL > 0
  43
  44 # if __ASSUME_PREAD_SYSCALL == 0
  45 static ssize_t __emulate_pread (int fd, void *buf, size_t count,
  46                                 off_t offset) internal_function;
  47 # endif
  48
  49 ssize_t
  50 __libc_pread (fd, buf, count, offset)
  51      int fd;
  52      void *buf;
  53      size_t count;
  54      off_t offset;
  55 {
  56   ssize_t result;
  57
  58 #if _MIPS_SIM != _ABI64
  59   assert (sizeof (offset) == 4);
  60 #endif
  61
  62   if (SINGLE_THREAD_P)
  63     {
  64       /* First try the syscall.  */
  65 #if _MIPS_SIM == _ABIN32 || _MIPS_SIM == _ABI64
  66       result = INLINE_SYSCALL (pread, 4, fd, CHECK_N (buf, count), count,
  67                                offset);
  68 #else
  69       result = INLINE_SYSCALL (pread, 6, fd, CHECK_N (buf, count), count, 0,
  70                                __LONG_LONG_PAIR (offset >> 31, offset));
  71 #endif
  72 # if __ASSUME_PREAD_SYSCALL == 0
  73       if (result == -1 && errno == ENOSYS)
  74         /* No system call available.  Use the emulation.  */
  75         result = __emulate_pread (fd, buf, count, offset);
  76 # endif
  77       return result;
  78     }
  79
  80   int oldtype = LIBC_CANCEL_ASYNC ();
  81
  82   /* First try the syscall.  */
  83 #if _MIPS_SIM == _ABIN32 || _MIPS_SIM == _ABI64
  84   result = INLINE_SYSCALL (pread, 4, fd, CHECK_N (buf, count), count, offset);
  85 #else
  86   result = INLINE_SYSCALL (pread, 6, fd, CHECK_N (buf, count), count, 0,
  87                            __LONG_LONG_PAIR (offset >> 31, offset));
  88 #endif
  89 # if __ASSUME_PREAD_SYSCALL == 0
  90   if (result == -1 && errno == ENOSYS)
  91     /* No system call available.  Use the emulation.  */
  92     result = __emulate_pread (fd, buf, count, offset);
  93 # endif
  94
  95   LIBC_CANCEL_RESET (oldtype);
  96
  97   return result;
  98 }
  99
 100 strong_alias (__libc_pread, __pread)
 101 weak_alias (__libc_pread, pread)
 102
 103 # define __libc_pread(fd, buf, count, offset) \
 104      static internal_function __emulate_pread (fd, buf, count, offset)
 105 #endif
 106
 107 #if __ASSUME_PREAD_SYSCALL == 0
 108 # include <sysdeps/posix/pread.c>
 109 #endif