ipc/chromium/src/base/file_descriptor_shuffle.cc@6474c204b198 (annotated)
ipc/chromium/src/base/file_descriptor_shuffle.cc
Wed, 31 Dec 2014 06:09:35 +0100
- author
- Michael Schloh von Bennewitz <michael@schloh.com>
- date
- Wed, 31 Dec 2014 06:09:35 +0100
- changeset 0
- 6474c204b198
- permissions
- -rw-r--r--
Cloned upstream origin tor-browser at tor-browser-31.3.0esr-4.5-1-build1
revision ID fc1c9ff7c1b2defdbc039f12214767608f46423f for hacking purpose.
| michael@0 | 1 | // Copyright (c) 2009 The Chromium Authors. All rights reserved. |
| michael@0 | 2 | // Use of this source code is governed by a BSD-style license that can be |
| michael@0 | 3 | // found in the LICENSE file. |
| michael@0 | 4 | |
| michael@0 | 5 | #include "base/file_descriptor_shuffle.h" |
| michael@0 | 6 | |
| michael@0 | 7 | #include <errno.h> |
| michael@0 | 8 | #include <unistd.h> |
| michael@0 | 9 | |
| michael@0 | 10 | #include "base/eintr_wrapper.h" |
| michael@0 | 11 | #include "base/logging.h" |
| michael@0 | 12 | |
| michael@0 | 13 | namespace base { |
| michael@0 | 14 | |
| michael@0 | 15 | bool PerformInjectiveMultimapDestructive( |
| michael@0 | 16 | InjectiveMultimap* m, InjectionDelegate* delegate) { |
| michael@0 | 17 | static const size_t kMaxExtraFDs = 16; |
| michael@0 | 18 | int extra_fds[kMaxExtraFDs]; |
| michael@0 | 19 | unsigned next_extra_fd = 0; |
| michael@0 | 20 | |
| michael@0 | 21 | // DANGER: this function may not allocate. |
| michael@0 | 22 | |
| michael@0 | 23 | for (InjectiveMultimap::iterator i = m->begin(); i != m->end(); ++i) { |
| michael@0 | 24 | int temp_fd = -1; |
| michael@0 | 25 | |
| michael@0 | 26 | // We DCHECK the injectiveness of the mapping. |
| michael@0 | 27 | for (InjectiveMultimap::iterator j = i + 1; j != m->end(); ++j) { |
| michael@0 | 28 | DCHECK(i->dest != j->dest) << "Both fd " << i->source |
| michael@0 | 29 | << " and " << j->source << " map to " << i->dest; |
| michael@0 | 30 | } |
| michael@0 | 31 | |
| michael@0 | 32 | const bool is_identity = i->source == i->dest; |
| michael@0 | 33 | |
| michael@0 | 34 | for (InjectiveMultimap::iterator j = i + 1; j != m->end(); ++j) { |
| michael@0 | 35 | if (!is_identity && i->dest == j->source) { |
| michael@0 | 36 | if (temp_fd == -1) { |
| michael@0 | 37 | if (!delegate->Duplicate(&temp_fd, i->dest)) |
| michael@0 | 38 | return false; |
| michael@0 | 39 | if (next_extra_fd < kMaxExtraFDs) { |
| michael@0 | 40 | extra_fds[next_extra_fd++] = temp_fd; |
| michael@0 | 41 | } else { |
| michael@0 | 42 | DLOG(ERROR) << "PerformInjectiveMultimapDestructive overflowed " |
| michael@0 | 43 | << "extra_fds. Leaking file descriptors!"; |
| michael@0 | 44 | } |
| michael@0 | 45 | } |
| michael@0 | 46 | |
| michael@0 | 47 | j->source = temp_fd; |
| michael@0 | 48 | j->close = false; |
| michael@0 | 49 | } |
| michael@0 | 50 | |
| michael@0 | 51 | if (i->close && i->source == j->dest) |
| michael@0 | 52 | i->close = false; |
| michael@0 | 53 | |
| michael@0 | 54 | if (i->close && i->source == j->source) { |
| michael@0 | 55 | i->close = false; |
| michael@0 | 56 | j->close = true; |
| michael@0 | 57 | } |
| michael@0 | 58 | } |
| michael@0 | 59 | |
| michael@0 | 60 | if (!is_identity) { |
| michael@0 | 61 | if (!delegate->Move(i->source, i->dest)) |
| michael@0 | 62 | return false; |
| michael@0 | 63 | } |
| michael@0 | 64 | |
| michael@0 | 65 | if (!is_identity && i->close) |
| michael@0 | 66 | delegate->Close(i->source); |
| michael@0 | 67 | } |
| michael@0 | 68 | |
| michael@0 | 69 | for (unsigned i = 0; i < next_extra_fd; i++) |
| michael@0 | 70 | delegate->Close(extra_fds[i]); |
| michael@0 | 71 | |
| michael@0 | 72 | return true; |
| michael@0 | 73 | } |
| michael@0 | 74 | |
| michael@0 | 75 | bool PerformInjectiveMultimap(const InjectiveMultimap& m_in, |
| michael@0 | 76 | InjectionDelegate* delegate) { |
| michael@0 | 77 | InjectiveMultimap m(m_in); |
| michael@0 | 78 | return PerformInjectiveMultimapDestructive(&m, delegate); |
| michael@0 | 79 | } |
| michael@0 | 80 | |
| michael@0 | 81 | bool FileDescriptorTableInjection::Duplicate(int* result, int fd) { |
| michael@0 | 82 | *result = HANDLE_EINTR(dup(fd)); |
| michael@0 | 83 | return *result >= 0; |
| michael@0 | 84 | } |
| michael@0 | 85 | |
| michael@0 | 86 | bool FileDescriptorTableInjection::Move(int src, int dest) { |
| michael@0 | 87 | return HANDLE_EINTR(dup2(src, dest)) != -1; |
| michael@0 | 88 | } |
| michael@0 | 89 | |
| michael@0 | 90 | void FileDescriptorTableInjection::Close(int fd) { |
| michael@0 | 91 | HANDLE_EINTR(close(fd)); |
| michael@0 | 92 | } |
| michael@0 | 93 | |
| michael@0 | 94 | } // namespace base |
