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// Copyright (c) 2009 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "base/file_descriptor_shuffle.h"
#include <errno.h>
#include <unistd.h>
#include "base/eintr_wrapper.h"
#include "base/logging.h"
namespace base {
bool PerformInjectiveMultimap(const InjectiveMultimap& m_in,
InjectionDelegate* delegate) {
InjectiveMultimap m(m_in);
std::vector<int> extra_fds;
for (InjectiveMultimap::iterator i = m.begin(); i != m.end(); ++i) {
int temp_fd = -1;
// We DCHECK the injectiveness of the mapping.
for (InjectiveMultimap::iterator j = i + 1; j != m.end(); ++j) {
DCHECK(i->dest != j->dest) << "Both fd " << i->source
<< " and " << j->source << " map to " << i->dest;
}
const bool is_identity = i->source == i->dest;
for (InjectiveMultimap::iterator j = i + 1; j != m.end(); ++j) {
if (!is_identity && i->dest == j->source) {
if (temp_fd == -1) {
if (!delegate->Duplicate(&temp_fd, i->dest))
return false;
extra_fds.push_back(temp_fd);
}
j->source = temp_fd;
j->close = false;
}
if (i->close && i->source == j->dest)
i->close = false;
if (i->close && i->source == j->source) {
i->close = false;
j->close = true;
}
}
if (!is_identity) {
if (!delegate->Move(i->source, i->dest))
return false;
}
if (!is_identity && i->close)
delegate->Close(i->source);
}
for (std::vector<int>::const_iterator
i = extra_fds.begin(); i != extra_fds.end(); ++i) {
delegate->Close(*i);
}
return true;
}
bool FileDescriptorTableInjection::Duplicate(int* result, int fd) {
*result = HANDLE_EINTR(dup(fd));
return *result >= 0;
}
bool FileDescriptorTableInjection::Move(int src, int dest) {
return HANDLE_EINTR(dup2(src, dest)) != -1;
}
void FileDescriptorTableInjection::Close(int fd) {
HANDLE_EINTR(close(fd));
}
} // namespace base
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