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

   1 /* Copyright (C) 1997, 1998, 2000, 2002, 2003, 2004, 2006
   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 #include <unistd.h>
  24 #include <endian.h>
  25
  26 #include <sysdep-cancel.h>
  27 #include <sys/syscall.h>
  28 #include <bp-checks.h>
  29
  30 #include <kernel-features.h>
  31
  32 #ifdef __NR_pread64             /* Newer kernels renamed but it's the same.  */
  33 # ifdef __NR_pread
  34 #  error "__NR_pread and __NR_pread64 both defined???"
  35 # endif
  36 # define __NR_pread __NR_pread64
  37 #endif
  38
  39 #if defined __NR_pread || __ASSUME_PREAD_SYSCALL > 0
  40
  41 # if __ASSUME_PREAD_SYSCALL == 0
  42 static ssize_t __emulate_pread (int fd, void *buf, size_t count,
  43                                 off_t offset) internal_function;
  44 # endif
  45
  46 ssize_t
  47 __libc_pread (fd, buf, count, offset)
  48      int fd;
  49      void *buf;
  50      size_t count;
  51      off_t offset;
  52 {
  53   ssize_t result;
  54
  55   if (SINGLE_THREAD_P)
  56     {
  57       /* First try the syscall.  */
  58       result = INLINE_SYSCALL (pread, 6, fd, CHECK_N (buf, count), count, 0,
  59                                __LONG_LONG_PAIR (offset >> 31, offset));
  60 # if __ASSUME_PREAD_SYSCALL == 0
  61       if (result == -1 && errno == ENOSYS)
  62         /* No system call available.  Use the emulation.  */
  63         result = __emulate_pread (fd, buf, count, offset);
  64 # endif
  65       return result;
  66     }
  67
  68   int oldtype = LIBC_CANCEL_ASYNC ();
  69
  70   /* First try the syscall.  */
  71   result = INLINE_SYSCALL (pread, 6, fd, CHECK_N (buf, count), count, 0,
  72                            __LONG_LONG_PAIR (offset >> 31, offset));
  73 # if __ASSUME_PREAD_SYSCALL == 0
  74   if (result == -1 && errno == ENOSYS)
  75     /* No system call available.  Use the emulation.  */
  76     result = __emulate_pread (fd, buf, count, offset);
  77 # endif
  78
  79   LIBC_CANCEL_RESET (oldtype);
  80
  81   return result;
  82 }
  83
  84 strong_alias (__libc_pread, __pread)
  85 weak_alias (__libc_pread, pread)
  86
  87 # define __libc_pread(fd, buf, count, offset) \
  88      static internal_function __emulate_pread (fd, buf, count, offset)
  89 #endif
  90
  91 #if __ASSUME_PREAD_SYSCALL == 0
  92 # include <sysdeps/posix/pread.c>
  93 #endif