sysdeps/unix/sysv/linux/powerpc/powerpc32/pread.c

   1 /* Copyright (C) 1997,1998,1999,2000,2002,2003,2006
   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, see
  18    <http://www.gnu.org/licenses/>.  */
  19
  20 #include <assert.h>
  21 #include <errno.h>
  22 #include <unistd.h>
  23
  24 #include <sysdep-cancel.h>
  25 #include <sys/syscall.h>
  26 #include <bp-checks.h>
  27
  28 #include <kernel-features.h>
  29
  30 #if defined __NR_pread || __ASSUME_PREAD_SYSCALL > 0
  31
  32 # if __ASSUME_PREAD_SYSCALL == 0
  33 static ssize_t __emulate_pread (int fd, void *buf, size_t count,
  34                                 off_t offset) internal_function;
  35 # endif
  36
  37
  38 ssize_t
  39 __libc_pread (fd, buf, count, offset)
  40      int fd;
  41      void *buf;
  42      size_t count;
  43      off_t offset;
  44 {
  45   ssize_t result;
  46
  47   if (SINGLE_THREAD_P)
  48     {
  49       /* On PPC32 64bit values are aligned in odd/even register pairs.  */
  50       result = INLINE_SYSCALL (pread, 6, fd, CHECK_N (buf, count), count,
  51                                0, offset >> 31, offset);
  52 # if __ASSUME_PREAD_SYSCALL == 0
  53       if (result == -1 && errno == ENOSYS)
  54         /* No system call available.  Use the emulation.  */
  55         result = __emulate_pread (fd, buf, count, offset);
  56 # endif
  57
  58       return result;
  59     }
  60
  61   int oldtype = LIBC_CANCEL_ASYNC ();
  62
  63   /* On PPC32 64bit values are aligned in odd/even register pairs.  */
  64   result = INLINE_SYSCALL (pread, 6, fd, CHECK_N (buf, count), count,
  65                                0, offset >> 31, offset);
  66 # if __ASSUME_PREAD_SYSCALL == 0
  67   if (result == -1 && errno == ENOSYS)
  68     /* No system call available.  Use the emulation.  */
  69     result = __emulate_pread (fd, buf, count, offset);
  70 # endif
  71
  72   LIBC_CANCEL_RESET (oldtype);
  73
  74   return result;
  75 }
  76
  77 strong_alias (__libc_pread, __pread)
  78 weak_alias (__libc_pread, pread)
  79
  80 # define __libc_pread(fd, buf, count, offset) \
  81      static internal_function __emulate_pread (fd, buf, count, offset)
  82 #endif
  83
  84 #if __ASSUME_PREAD_SYSCALL == 0
  85 # include <sysdeps/posix/pread.c>
  86 #endif