Line data    Source code

       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           0 : MemoryMappedFile::MemoryMappedFile() {}
      48             : 
      49           0 : MemoryMappedFile::MemoryMappedFile(const char* path, size_t offset) {
      50           0 :   Map(path, offset);
      51           0 : }
      52             : 
      53           0 : MemoryMappedFile::~MemoryMappedFile() {
      54           0 :   Unmap();
      55           0 : }
      56             : 
      57             : #include <unistd.h>
      58             : 
      59           0 : bool MemoryMappedFile::Map(const char* path, size_t offset) {
      60           0 :   Unmap();
      61             : 
      62           0 :   int fd = sys_open(path, O_RDONLY, 0);
      63           0 :   if (fd == -1) {
      64           0 :     return false;
      65             :   }
      66             : 
      67             : #if defined(__x86_64__) || defined(__aarch64__) || \
      68             :    (defined(__mips__) && _MIPS_SIM == _ABI64)
      69             : 
      70             :   struct kernel_stat st;
      71           0 :   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           0 :     sys_close(fd);
      77           0 :     return false;
      78             :   }
      79             : 
      80             :   // Strangely file size can be negative, but we check above that it is not.
      81           0 :   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           0 :   if (offset >= file_len) {
      86           0 :     sys_close(fd);
      87           0 :     return true;
      88             :   }
      89             : 
      90           0 :   void* data = sys_mmap(NULL, file_len, PROT_READ, MAP_PRIVATE, fd, offset);
      91           0 :   sys_close(fd);
      92           0 :   if (data == MAP_FAILED) {
      93           0 :     return false;
      94             :   }
      95             : 
      96           0 :   content_.Set(data, file_len - offset);
      97           0 :   return true;
      98             : }
      99             : 
     100           0 : void MemoryMappedFile::Unmap() {
     101           0 :   if (content_.data()) {
     102           0 :     sys_munmap(const_cast<uint8_t*>(content_.data()), content_.length());
     103           0 :     content_.Set(NULL, 0);
     104             :   }
     105           0 : }
     106             : 
     107             : }  // namespace google_breakpad