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comparison: ipc/chromium/src/base/file_descriptor_shuffle.cc
ipc/chromium/src/base/file_descriptor_shuffle.cc
- changeset 0
- 6474c204b198
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| -1:000000000000 | 0:f094bd5d1106 |
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| 1 // Copyright (c) 2009 The Chromium Authors. All rights reserved. | |
| 2 // Use of this source code is governed by a BSD-style license that can be | |
| 3 // found in the LICENSE file. | |
| 4 | |
| 5 #include "base/file_descriptor_shuffle.h" | |
| 6 | |
| 7 #include <errno.h> | |
| 8 #include <unistd.h> | |
| 9 | |
| 10 #include "base/eintr_wrapper.h" | |
| 11 #include "base/logging.h" | |
| 12 | |
| 13 namespace base { | |
| 14 | |
| 15 bool PerformInjectiveMultimapDestructive( | |
| 16 InjectiveMultimap* m, InjectionDelegate* delegate) { | |
| 17 static const size_t kMaxExtraFDs = 16; | |
| 18 int extra_fds[kMaxExtraFDs]; | |
| 19 unsigned next_extra_fd = 0; | |
| 20 | |
| 21 // DANGER: this function may not allocate. | |
| 22 | |
| 23 for (InjectiveMultimap::iterator i = m->begin(); i != m->end(); ++i) { | |
| 24 int temp_fd = -1; | |
| 25 | |
| 26 // We DCHECK the injectiveness of the mapping. | |
| 27 for (InjectiveMultimap::iterator j = i + 1; j != m->end(); ++j) { | |
| 28 DCHECK(i->dest != j->dest) << "Both fd " << i->source | |
| 29 << " and " << j->source << " map to " << i->dest; | |
| 30 } | |
| 31 | |
| 32 const bool is_identity = i->source == i->dest; | |
| 33 | |
| 34 for (InjectiveMultimap::iterator j = i + 1; j != m->end(); ++j) { | |
| 35 if (!is_identity && i->dest == j->source) { | |
| 36 if (temp_fd == -1) { | |
| 37 if (!delegate->Duplicate(&temp_fd, i->dest)) | |
| 38 return false; | |
| 39 if (next_extra_fd < kMaxExtraFDs) { | |
| 40 extra_fds[next_extra_fd++] = temp_fd; | |
| 41 } else { | |
| 42 DLOG(ERROR) << "PerformInjectiveMultimapDestructive overflowed " | |
| 43 << "extra_fds. Leaking file descriptors!"; | |
| 44 } | |
| 45 } | |
| 46 | |
| 47 j->source = temp_fd; | |
| 48 j->close = false; | |
| 49 } | |
| 50 | |
| 51 if (i->close && i->source == j->dest) | |
| 52 i->close = false; | |
| 53 | |
| 54 if (i->close && i->source == j->source) { | |
| 55 i->close = false; | |
| 56 j->close = true; | |
| 57 } | |
| 58 } | |
| 59 | |
| 60 if (!is_identity) { | |
| 61 if (!delegate->Move(i->source, i->dest)) | |
| 62 return false; | |
| 63 } | |
| 64 | |
| 65 if (!is_identity && i->close) | |
| 66 delegate->Close(i->source); | |
| 67 } | |
| 68 | |
| 69 for (unsigned i = 0; i < next_extra_fd; i++) | |
| 70 delegate->Close(extra_fds[i]); | |
| 71 | |
| 72 return true; | |
| 73 } | |
| 74 | |
| 75 bool PerformInjectiveMultimap(const InjectiveMultimap& m_in, | |
| 76 InjectionDelegate* delegate) { | |
| 77 InjectiveMultimap m(m_in); | |
| 78 return PerformInjectiveMultimapDestructive(&m, delegate); | |
| 79 } | |
| 80 | |
| 81 bool FileDescriptorTableInjection::Duplicate(int* result, int fd) { | |
| 82 *result = HANDLE_EINTR(dup(fd)); | |
| 83 return *result >= 0; | |
| 84 } | |
| 85 | |
| 86 bool FileDescriptorTableInjection::Move(int src, int dest) { | |
| 87 return HANDLE_EINTR(dup2(src, dest)) != -1; | |
| 88 } | |
| 89 | |
| 90 void FileDescriptorTableInjection::Close(int fd) { | |
| 91 HANDLE_EINTR(close(fd)); | |
| 92 } | |
| 93 | |
| 94 } // namespace base |
