93 lines
3 KiB
C++
93 lines
3 KiB
C++
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/*
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* Copyright (c) 2008 The Hewlett-Packard Development Company
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are
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* met: redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer;
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* redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution;
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* neither the name of the copyright holders nor the names of its
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* contributors may be used to endorse or promote products derived from
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* this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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* Authors: Nathan Binkert
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*/
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#include <cerrno>
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#include <cstdio>
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#include "base/atomicio.hh"
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ssize_t
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atomic_read(int fd, void *s, size_t n)
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{
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char *p = reinterpret_cast<char *>(s);
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ssize_t pos = 0;
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// Keep reading until we've gotten all of the data.
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while (n > pos) {
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ssize_t result = read(fd, p + pos, n - pos);
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// We didn't get any more data, so we should probably punt,
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// otherwise we'd just keep spinning
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if (result == 0)
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break;
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// If there was an error, try again on EINTR/EAGAIN, pass the
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// error up otherwise.
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if (result == -1) {
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if (errno == EINTR || errno == EAGAIN)
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continue;
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return result;
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}
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pos += result;
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}
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return pos;
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}
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ssize_t
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atomic_write(int fd, const void *s, size_t n)
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{
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const char *p = reinterpret_cast<const char *>(s);
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ssize_t pos = 0;
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// Keep writing until we've written all of the data
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while (n > pos) {
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ssize_t result = write(fd, p + pos, n - pos);
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// We didn't manage to write anything this time, so we should
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// probably punt, otherwise we'd just keep spinning
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if (result == 0)
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break;
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// If there was an error, try again on EINTR/EAGAIN, pass the
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// error up otherwise.
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if (result == -1) {
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if (errno == EINTR || errno == EAGAIN)
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continue;
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return result;
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}
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pos += result;
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}
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return pos;
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}
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