1 files changed, 96 insertions, 0 deletions
diff --git a/ipc/chromium/src/base/file_descriptor_shuffle.cc b/ipc/chromium/src/base/file_descriptor_shuffle.cc
new file mode 100644
index 0000000000..13f0c1e705
--- /dev/null
+++ b/ipc/chromium/src/base/file_descriptor_shuffle.cc
@@ -0,0 +1,96 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+// 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 PerformInjectiveMultimapDestructive(
+    InjectiveMultimap* m, InjectionDelegate* delegate) {
+  static const size_t kMaxExtraFDs = 16;
+  int extra_fds[kMaxExtraFDs];
+  unsigned next_extra_fd = 0;
+
+  // DANGER: this function may not allocate.
+
+  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;
+          if (next_extra_fd < kMaxExtraFDs) {
+            extra_fds[next_extra_fd++] = temp_fd;
+          } else {
+              DLOG(ERROR) << "PerformInjectiveMultimapDestructive overflowed "
+                          << "extra_fds. Leaking file descriptors!";
+          }
+        }
+
+        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 (unsigned i = 0; i < next_extra_fd; i++)
+    delegate->Close(extra_fds[i]);
+
+  return true;
+}
+
+bool PerformInjectiveMultimap(const InjectiveMultimap& m_in,
+                              InjectionDelegate* delegate) {
+    InjectiveMultimap m(m_in);
+    return PerformInjectiveMultimapDestructive(&m, delegate);
+}
+
+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