1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/ipc/chromium/src/base/file_descriptor_shuffle.cc Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,94 @@
1.4 +// Copyright (c) 2009 The Chromium Authors. All rights reserved.
1.5 +// Use of this source code is governed by a BSD-style license that can be
1.6 +// found in the LICENSE file.
1.7 +
1.8 +#include "base/file_descriptor_shuffle.h"
1.9 +
1.10 +#include <errno.h>
1.11 +#include <unistd.h>
1.12 +
1.13 +#include "base/eintr_wrapper.h"
1.14 +#include "base/logging.h"
1.15 +
1.16 +namespace base {
1.17 +
1.18 +bool PerformInjectiveMultimapDestructive(
1.19 + InjectiveMultimap* m, InjectionDelegate* delegate) {
1.20 + static const size_t kMaxExtraFDs = 16;
1.21 + int extra_fds[kMaxExtraFDs];
1.22 + unsigned next_extra_fd = 0;
1.23 +
1.24 + // DANGER: this function may not allocate.
1.25 +
1.26 + for (InjectiveMultimap::iterator i = m->begin(); i != m->end(); ++i) {
1.27 + int temp_fd = -1;
1.28 +
1.29 + // We DCHECK the injectiveness of the mapping.
1.30 + for (InjectiveMultimap::iterator j = i + 1; j != m->end(); ++j) {
1.31 + DCHECK(i->dest != j->dest) << "Both fd " << i->source
1.32 + << " and " << j->source << " map to " << i->dest;
1.33 + }
1.34 +
1.35 + const bool is_identity = i->source == i->dest;
1.36 +
1.37 + for (InjectiveMultimap::iterator j = i + 1; j != m->end(); ++j) {
1.38 + if (!is_identity && i->dest == j->source) {
1.39 + if (temp_fd == -1) {
1.40 + if (!delegate->Duplicate(&temp_fd, i->dest))
1.41 + return false;
1.42 + if (next_extra_fd < kMaxExtraFDs) {
1.43 + extra_fds[next_extra_fd++] = temp_fd;
1.44 + } else {
1.45 + DLOG(ERROR) << "PerformInjectiveMultimapDestructive overflowed "
1.46 + << "extra_fds. Leaking file descriptors!";
1.47 + }
1.48 + }
1.49 +
1.50 + j->source = temp_fd;
1.51 + j->close = false;
1.52 + }
1.53 +
1.54 + if (i->close && i->source == j->dest)
1.55 + i->close = false;
1.56 +
1.57 + if (i->close && i->source == j->source) {
1.58 + i->close = false;
1.59 + j->close = true;
1.60 + }
1.61 + }
1.62 +
1.63 + if (!is_identity) {
1.64 + if (!delegate->Move(i->source, i->dest))
1.65 + return false;
1.66 + }
1.67 +
1.68 + if (!is_identity && i->close)
1.69 + delegate->Close(i->source);
1.70 + }
1.71 +
1.72 + for (unsigned i = 0; i < next_extra_fd; i++)
1.73 + delegate->Close(extra_fds[i]);
1.74 +
1.75 + return true;
1.76 +}
1.77 +
1.78 +bool PerformInjectiveMultimap(const InjectiveMultimap& m_in,
1.79 + InjectionDelegate* delegate) {
1.80 + InjectiveMultimap m(m_in);
1.81 + return PerformInjectiveMultimapDestructive(&m, delegate);
1.82 +}
1.83 +
1.84 +bool FileDescriptorTableInjection::Duplicate(int* result, int fd) {
1.85 + *result = HANDLE_EINTR(dup(fd));
1.86 + return *result >= 0;
1.87 +}
1.88 +
1.89 +bool FileDescriptorTableInjection::Move(int src, int dest) {
1.90 + return HANDLE_EINTR(dup2(src, dest)) != -1;
1.91 +}
1.92 +
1.93 +void FileDescriptorTableInjection::Close(int fd) {
1.94 + HANDLE_EINTR(close(fd));
1.95 +}
1.96 +
1.97 +} // namespace base
