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      1 // Copyright (c) 2013 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/debug/proc_maps_linux.h"
      6 
      7 #if defined(OS_LINUX)
      8 #include <inttypes.h>
      9 #endif
     10 
     11 #include "base/file_util.h"
     12 #include "base/strings/string_split.h"
     13 
     14 #if defined(OS_ANDROID)
     15 // Bionic's inttypes.h defines PRI/SCNxPTR as an unsigned long int, which
     16 // is incompatible with Bionic's stdint.h defining uintptr_t as a unsigned int:
     17 // https://code.google.com/p/android/issues/detail?id=57218
     18 #undef SCNxPTR
     19 #define SCNxPTR "x"
     20 #endif
     21 
     22 namespace base {
     23 namespace debug {
     24 
     25 bool ReadProcMaps(std::string* proc_maps) {
     26   FilePath proc_maps_path("/proc/self/maps");
     27   return file_util::ReadFileToString(proc_maps_path, proc_maps);
     28 }
     29 
     30 bool ParseProcMaps(const std::string& input,
     31                    std::vector<MappedMemoryRegion>* regions_out) {
     32   std::vector<MappedMemoryRegion> regions;
     33 
     34   // This isn't async safe nor terribly efficient, but it doesn't need to be at
     35   // this point in time.
     36   std::vector<std::string> lines;
     37   SplitString(input, '\n', &lines);
     38 
     39   for (size_t i = 0; i < lines.size(); ++i) {
     40     // Due to splitting on '\n' the last line should be empty.
     41     if (i == lines.size() - 1) {
     42       if (!lines[i].empty())
     43         return false;
     44       break;
     45     }
     46 
     47     MappedMemoryRegion region;
     48     const char* line = lines[i].c_str();
     49     char permissions[5] = {'\0'};  // Ensure NUL-terminated string.
     50     uint8 dev_major = 0;
     51     uint8 dev_minor = 0;
     52     long inode = 0;
     53     int path_index = 0;
     54 
     55     // Sample format from man 5 proc:
     56     //
     57     // address           perms offset  dev   inode   pathname
     58     // 08048000-08056000 r-xp 00000000 03:0c 64593   /usr/sbin/gpm
     59     //
     60     // The final %n term captures the offset in the input string, which is used
     61     // to determine the path name. It *does not* increment the return value.
     62     // Refer to man 3 sscanf for details.
     63     if (sscanf(line, "%" SCNxPTR "-%" SCNxPTR " %4c %llx %hhx:%hhx %ld %n",
     64                &region.start, &region.end, permissions, &region.offset,
     65                &dev_major, &dev_minor, &inode, &path_index) < 7) {
     66       return false;
     67     }
     68 
     69     region.permissions = 0;
     70 
     71     if (permissions[0] == 'r')
     72       region.permissions |= MappedMemoryRegion::READ;
     73     else if (permissions[0] != '-')
     74       return false;
     75 
     76     if (permissions[1] == 'w')
     77       region.permissions |= MappedMemoryRegion::WRITE;
     78     else if (permissions[1] != '-')
     79       return false;
     80 
     81     if (permissions[2] == 'x')
     82       region.permissions |= MappedMemoryRegion::EXECUTE;
     83     else if (permissions[2] != '-')
     84       return false;
     85 
     86     if (permissions[3] == 'p')
     87       region.permissions |= MappedMemoryRegion::PRIVATE;
     88     else if (permissions[3] != 's' && permissions[3] != 'S')  // Shared memory.
     89       return false;
     90 
     91     // Pushing then assigning saves us a string copy.
     92     regions.push_back(region);
     93     regions.back().path.assign(line + path_index);
     94   }
     95 
     96   regions_out->swap(regions);
     97   return true;
     98 }
     99 
    100 }  // namespace debug
    101 }  // namespace base
    102