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75 lines
2.1 KiB
C
75 lines
2.1 KiB
C
/* readv supports all Linux kernels >= 2.0.
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Copyright (C) 1997-2013 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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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, see
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<http://www.gnu.org/licenses/>. */
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#include <errno.h>
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#include <stddef.h>
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#include <sys/param.h>
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#include <sys/uio.h>
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#include <sysdep-cancel.h>
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#include <sys/syscall.h>
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#include <kernel-features.h>
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#ifndef __ASSUME_COMPLETE_READV_WRITEV
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static ssize_t __atomic_readv_replacement (int, const struct iovec *,
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int) internal_function;
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#endif
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/* Not all versions of the kernel support the large number of records. */
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#ifndef UIO_FASTIOV
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# define UIO_FASTIOV 8 /* 8 is a safe number. */
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#endif
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ssize_t
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__libc_readv (fd, vector, count)
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int fd;
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const struct iovec *vector;
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int count;
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{
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ssize_t result;
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if (SINGLE_THREAD_P)
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result = INLINE_SYSCALL (readv, 3, fd, vector, count);
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else
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{
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int oldtype = LIBC_CANCEL_ASYNC ();
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result = INLINE_SYSCALL (readv, 3, fd, vector, count);
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LIBC_CANCEL_RESET (oldtype);
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}
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#ifdef __ASSUME_COMPLETE_READV_WRITEV
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return result;
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#else
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if (result >= 0 || errno != EINVAL || count <= UIO_FASTIOV)
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return result;
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return __atomic_readv_replacement (fd, vector, count);
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#endif
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}
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strong_alias (__libc_readv, __readv)
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weak_alias (__libc_readv, readv)
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#ifndef __ASSUME_COMPLETE_READV_WRITEV
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# define __libc_readv static internal_function __atomic_readv_replacement
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# include <sysdeps/posix/readv.c>
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#endif
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