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/* Copyright (C) 1997-2000,2002,2003,2004,2006 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
#include <assert.h>
#include <errno.h>
#include <endian.h>
#include <unistd.h>
#include <sysdep-cancel.h>
#include <sys/syscall.h>
#include <bp-checks.h>
#include <kernel-features.h>
#ifdef __NR_pread64 /* Newer kernels renamed but it's the same. */
# ifdef __NR_pread
# error "__NR_pread and __NR_pread64 both defined???"
# endif
# define __NR_pread __NR_pread64
#endif
#if defined __NR_pread || __ASSUME_PREAD_SYSCALL > 0
# if __ASSUME_PREAD_SYSCALL == 0
static ssize_t __emulate_pread (int fd, void *buf, size_t count,
off_t offset) internal_function;
# endif
static ssize_t
#ifdef NO_CANCELLATION
inline __attribute ((always_inline))
#endif
do_pread (int fd, void *buf, size_t count, off_t offset)
{
ssize_t result;
/* First try the syscall. */
assert (sizeof (offset) == 4);
result = INLINE_SYSCALL (pread, 5, fd, CHECK_N (buf, count), count,
__LONG_LONG_PAIR (offset >> 31, offset));
# if __ASSUME_PREAD_SYSCALL == 0
if (result == -1 && errno == ENOSYS)
/* No system call available. Use the emulation. */
result = __emulate_pread (fd, buf, count, offset);
# endif
return result;
}
ssize_t
__libc_pread (fd, buf, count, offset)
int fd;
void *buf;
size_t count;
off_t offset;
{
if (SINGLE_THREAD_P)
return do_pread (fd, buf, count, offset);
int oldtype = LIBC_CANCEL_ASYNC ();
ssize_t result = do_pread (fd, buf, count, offset);
LIBC_CANCEL_RESET (oldtype);
return result;
}
strong_alias (__libc_pread, __pread)
weak_alias (__libc_pread, pread)
# define __libc_pread(fd, buf, count, offset) \
static internal_function __emulate_pread (fd, buf, count, offset)
#endif
#if __ASSUME_PREAD_SYSCALL == 0
# include <sysdeps/posix/pread.c>
#endif
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