1 | // Copyright (c) 2011, Google Inc. |
2 | // All rights reserved. |
3 | // |
4 | // Redistribution and use in source and binary forms, with or without |
5 | // modification, are permitted provided that the following conditions are |
6 | // met: |
7 | // |
8 | // * Redistributions of source code must retain the above copyright |
9 | // notice, this list of conditions and the following disclaimer. |
10 | // * Redistributions in binary form must reproduce the above |
11 | // copyright notice, this list of conditions and the following disclaimer |
12 | // in the documentation and/or other materials provided with the |
13 | // distribution. |
14 | // * Neither the name of Google Inc. nor the names of its |
15 | // contributors may be used to endorse or promote products derived from |
16 | // this software without specific prior written permission. |
17 | // |
18 | // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
19 | // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
20 | // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR |
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25 | // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
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28 | // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
29 | |
30 | // memory_mapped_file.cc: Implement google_breakpad::MemoryMappedFile. |
31 | // See memory_mapped_file.h for details. |
32 | |
33 | #include "common/linux/memory_mapped_file.h" |
34 | |
35 | #include <fcntl.h> |
36 | #include <sys/mman.h> |
37 | #if defined(__ANDROID__) |
38 | #include <sys/stat.h> |
39 | #endif |
40 | #include <unistd.h> |
41 | |
42 | #include "common/memory_range.h" |
43 | #include "third_party/lss/linux_syscall_support.h" |
44 | |
45 | namespace google_breakpad { |
46 | |
47 | MemoryMappedFile::MemoryMappedFile() {} |
48 | |
49 | MemoryMappedFile::MemoryMappedFile(const char* path, size_t offset) { |
50 | Map(path, offset); |
51 | } |
52 | |
53 | MemoryMappedFile::~MemoryMappedFile() { |
54 | Unmap(); |
55 | } |
56 | |
57 | #include <unistd.h> |
58 | |
59 | bool MemoryMappedFile::Map(const char* path, size_t offset) { |
60 | Unmap(); |
61 | |
62 | int fd = sys_open(path, O_RDONLY, 0); |
63 | if (fd == -1) { |
64 | return false; |
65 | } |
66 | |
67 | #if defined(__x86_64__) || defined(__aarch64__) || \ |
68 | (defined(__mips__) && _MIPS_SIM == _ABI64) |
69 | |
70 | struct kernel_stat st; |
71 | if (sys_fstat(fd, &st) == -1 || st.st_size < 0) { |
72 | #else |
73 | struct kernel_stat64 st; |
74 | if (sys_fstat64(fd, &st) == -1 || st.st_size < 0) { |
75 | #endif |
76 | sys_close(fd); |
77 | return false; |
78 | } |
79 | |
80 | // Strangely file size can be negative, but we check above that it is not. |
81 | size_t file_len = static_cast<size_t>(st.st_size); |
82 | // If the file does not extend beyond the offset, simply use an empty |
83 | // MemoryRange and return true. Don't bother to call mmap() |
84 | // even though mmap() can handle an empty file on some platforms. |
85 | if (offset >= file_len) { |
86 | sys_close(fd); |
87 | return true; |
88 | } |
89 | |
90 | size_t content_len = file_len - offset; |
91 | void* data = sys_mmap(NULL, content_len, PROT_READ, MAP_PRIVATE, fd, offset); |
92 | sys_close(fd); |
93 | if (data == MAP_FAILED) { |
94 | return false; |
95 | } |
96 | |
97 | content_.Set(data, content_len); |
98 | return true; |
99 | } |
100 | |
101 | void MemoryMappedFile::Unmap() { |
102 | if (content_.data()) { |
103 | sys_munmap(const_cast<uint8_t*>(content_.data()), content_.length()); |
104 | content_.Set(NULL, 0); |
105 | } |
106 | } |
107 | |
108 | } // namespace google_breakpad |
109 | |