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