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.h: Define the google_breakpad::MemoryMappedFile 31 // class, which maps a file into memory for read-only access. 32 33 #ifndef COMMON_LINUX_MEMORY_MAPPED_FILE_H_ 34 #define COMMON_LINUX_MEMORY_MAPPED_FILE_H_ 35 36 #include <stddef.h> 37 #include "common/basictypes.h" 38 #include "common/memory_range.h" 39 40 namespace google_breakpad { 41 42 // A utility class for mapping a file into memory for read-only access of 43 // the file content. Its implementation avoids calling into libc functions 44 // by directly making system calls for open, close, mmap, and munmap. 45 class MemoryMappedFile { 46 public: 47 MemoryMappedFile(); 48 49 // Constructor that calls Map() to map a file at |path| into memory. 50 // If Map() fails, the object behaves as if it is default constructed. 51 MemoryMappedFile(const char* path, size_t offset); 52 53 ~MemoryMappedFile(); 54 55 // Maps a file at |path| into memory, which can then be accessed via 56 // content() as a MemoryRange object or via data(), and returns true on 57 // success. Mapping an empty file will succeed but with data() and size() 58 // returning NULL and 0, respectively. An existing mapping is unmapped 59 // before a new mapping is created. 60 bool Map(const char* path, size_t offset); 61 62 // Unmaps the memory for the mapped file. It's a no-op if no file is 63 // mapped. 64 void Unmap(); 65 66 // Returns a MemoryRange object that covers the memory for the mapped 67 // file. The MemoryRange object is empty if no file is mapped. 68 const MemoryRange& content() const { return content_; } 69 70 // Returns a pointer to the beginning of the memory for the mapped file. 71 // or NULL if no file is mapped or the mapped file is empty. 72 const void* data() const { return content_.data(); } 73 74 // Returns the size in bytes of the mapped file, or zero if no file 75 // is mapped. 76 size_t size() const { return content_.length(); } 77 78 private: 79 // Mapped file content as a MemoryRange object. 80 MemoryRange content_; 81 82 DISALLOW_COPY_AND_ASSIGN(MemoryMappedFile); 83 }; 84 85 } // namespace google_breakpad 86 87 #endif // COMMON_LINUX_MEMORY_MAPPED_FILE_H_ 88
