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97 lines
2.6 KiB
C
97 lines
2.6 KiB
C
/* Copyright (C) 1997-2000,2002,2003,2004 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, write to the Free
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Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
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02111-1307 USA. */
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#include <assert.h>
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#include <errno.h>
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#include <endian.h>
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#include <unistd.h>
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#include <sysdep-cancel.h>
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#include <sys/syscall.h>
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#include <bp-checks.h>
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#include "kernel-features.h"
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#ifdef __NR_pread64 /* Newer kernels renamed but it's the same. */
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# ifdef __NR_pread
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# error "__NR_pread and __NR_pread64 both defined???"
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# endif
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# define __NR_pread __NR_pread64
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#endif
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#if defined __NR_pread || __ASSUME_PREAD_SYSCALL > 0
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# if __ASSUME_PREAD_SYSCALL == 0
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static ssize_t __emulate_pread (int fd, void *buf, size_t count,
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off_t offset) internal_function;
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# endif
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static ssize_t
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#ifdef NO_CANCELLATION
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inline __attribute ((always_inline))
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#endif
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do_pread (int fd, void *buf, size_t count, off_t offset)
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{
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ssize_t result;
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/* First try the syscall. */
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assert (sizeof (offset) == 4);
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result = INLINE_SYSCALL (pread, 5, fd, CHECK_N (buf, count), count,
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__LONG_LONG_PAIR (offset >> 31, offset));
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# if __ASSUME_PREAD_SYSCALL == 0
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if (result == -1 && errno == ENOSYS)
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/* No system call available. Use the emulation. */
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result = __emulate_pread (fd, buf, count, offset);
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# endif
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return result;
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}
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ssize_t
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__libc_pread (fd, buf, count, offset)
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int fd;
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void *buf;
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size_t count;
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off_t offset;
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{
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if (SINGLE_THREAD_P)
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return do_pread (fd, buf, count, offset);
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int oldtype = LIBC_CANCEL_ASYNC ();
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ssize_t result = do_pread (fd, buf, count, offset);
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LIBC_CANCEL_RESET (oldtype);
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return result;
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}
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strong_alias (__libc_pread, __pread)
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weak_alias (__libc_pread, pread)
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# define __libc_pread(fd, buf, count, offset) \
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static internal_function __emulate_pread (fd, buf, count, offset)
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#endif
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#if __ASSUME_PREAD_SYSCALL == 0
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# include <sysdeps/posix/pread.c>
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#endif
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