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 21 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 22 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 23 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 24 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 25 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 26 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 27 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 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 #if defined(__x86_64__) || defined(__aarch64__) || \ 91 (defined(__mips__) && _MIPS_SIM == _ABI64) 92 void* data = sys_mmap(NULL, file_len, PROT_READ, MAP_PRIVATE, fd, offset); 93 #else 94 if ((offset & 4095) != 0) { 95 // Not page aligned. 96 sys_close(fd); 97 return false; 98 } 99 void* data = sys_mmap2( 100 NULL, file_len, PROT_READ, MAP_PRIVATE, fd, offset >> 12); 101 #endif 102 sys_close(fd); 103 if (data == MAP_FAILED) { 104 return false; 105 } 106 107 content_.Set(data, file_len - offset); 108 return true; 109 } 110 111 void MemoryMappedFile::Unmap() { 112 if (content_.data()) { 113 sys_munmap(const_cast<uint8_t*>(content_.data()), content_.length()); 114 content_.Set(NULL, 0); 115 } 116 } 117 118 } // namespace google_breakpad 119
