base/trace_event/process_memory_maps_dump_provider.cc

   1 // Copyright 2015 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/trace_event/process_memory_maps_dump_provider.h"
   6
   7 #include <cctype>
   8 #include <fstream>
   9
  10 #include "base/logging.h"
  11 #include "base/process/process_metrics.h"
  12 #include "base/trace_event/process_memory_dump.h"
  13 #include "base/trace_event/process_memory_maps.h"
  14
  15 namespace base {
  16 namespace trace_event {
  17
  18 #if defined(OS_LINUX) || defined(OS_ANDROID)
  19 // static
  20 std::istream* ProcessMemoryMapsDumpProvider::proc_smaps_for_testing = nullptr;
  21
  22 namespace {
  23
  24 const uint32 kMaxLineSize = 4096;
  25
  26 bool ParseSmapsHeader(std::istream* smaps,
  27                       ProcessMemoryMaps::VMRegion* region) {
  28   // e.g., "00400000-00421000 r-xp 00000000 fc:01 1234  /foo.so\n"
  29   bool res = true;  // Whether this region should be appended or skipped.
  30   uint64 end_addr;
  31   std::string protection_flags;
  32   std::string ignored;
  33   *smaps >> std::hex >> region->start_address;
  34   smaps->ignore(1);
  35   *smaps >> std::hex >> end_addr;
  36   if (end_addr > region->start_address) {
  37     region->size_in_bytes = end_addr - region->start_address;
  38   } else {
  39     // This is not just paranoia, it can actually happen (See crbug.com/461237).
  40     region->size_in_bytes = 0;
  41     res = false;
  42   }
  43
  44   region->protection_flags = 0;
  45   *smaps >> protection_flags;
  46   CHECK_EQ(4UL, protection_flags.size());
  47   if (protection_flags[0] == 'r') {
  48     region->protection_flags |=
  49         ProcessMemoryMaps::VMRegion::kProtectionFlagsRead;
  50   }
  51   if (protection_flags[1] == 'w') {
  52     region->protection_flags |=
  53         ProcessMemoryMaps::VMRegion::kProtectionFlagsWrite;
  54   }
  55   if (protection_flags[2] == 'x') {
  56     region->protection_flags |=
  57         ProcessMemoryMaps::VMRegion::kProtectionFlagsExec;
  58   }
  59   *smaps >> ignored;  // Ignore mapped file offset.
  60   *smaps >> ignored;  // Ignore device maj-min (fc:01 in the example above).
  61   *smaps >> ignored;  // Ignore inode number (1234 in the example above).
  62
  63   while (smaps->peek() == ' ')
  64     smaps->ignore(1);
  65   char mapped_file[kMaxLineSize];
  66   smaps->getline(mapped_file, sizeof(mapped_file));
  67   region->mapped_file = mapped_file;
  68
  69   return res;
  70 }
  71
  72 uint64 ReadCounterBytes(std::istream* smaps) {
  73   uint64 counter_value = 0;
  74   *smaps >> std::dec >> counter_value;
  75   return counter_value * 1024;
  76 }
  77
  78 uint32 ParseSmapsCounter(std::istream* smaps,
  79                          ProcessMemoryMaps::VMRegion* region) {
  80   // A smaps counter lines looks as follows: "RSS:  0 Kb\n"
  81   uint32 res = 1;
  82   std::string counter_name;
  83   *smaps >> counter_name;
  84
  85   // TODO(primiano): "Swap" should also be accounted as resident. Check
  86   // whether Rss isn't already counting swapped and fix below if that is
  87   // the case.
  88   if (counter_name == "Pss:") {
  89     region->byte_stats_proportional_resident = ReadCounterBytes(smaps);
  90   } else if (counter_name == "Private_Dirty:") {
  91     region->byte_stats_private_dirty_resident = ReadCounterBytes(smaps);
  92   } else if (counter_name == "Private_Clean:") {
  93     region->byte_stats_private_clean_resident = ReadCounterBytes(smaps);
  94   } else if (counter_name == "Shared_Dirty:") {
  95     region->byte_stats_shared_dirty_resident = ReadCounterBytes(smaps);
  96   } else if (counter_name == "Shared_Clean:") {
  97     region->byte_stats_shared_clean_resident = ReadCounterBytes(smaps);
  98   } else if (counter_name == "Swap:") {
  99     region->byte_stats_swapped = ReadCounterBytes(smaps);
 100   } else {
 101     res = 0;
 102   }
 103
 104 #ifndef NDEBUG
 105   // Paranoid check against changes of the Kernel /proc interface.
 106   if (res) {
 107     std::string unit;
 108     *smaps >> unit;
 109     DCHECK_EQ("kB", unit);
 110   }
 111 #endif
 112
 113   smaps->ignore(kMaxLineSize, '\n');
 114
 115   return res;
 116 }
 117
 118 uint32 ReadLinuxProcSmapsFile(std::istream* smaps, ProcessMemoryMaps* pmm) {
 119   if (!smaps->good())
 120     return 0;
 121
 122   const uint32 kNumExpectedCountersPerRegion = 6;
 123   uint32 counters_parsed_for_current_region = 0;
 124   uint32 num_valid_regions = 0;
 125   ProcessMemoryMaps::VMRegion region;
 126   bool should_add_current_region = false;
 127   for (;;) {
 128     int next = smaps->peek();
 129     if (next == std::ifstream::traits_type::eof() || next == '\n')
 130       break;
 131     if (isxdigit(next) && !isupper(next)) {
 132       region = ProcessMemoryMaps::VMRegion();
 133       counters_parsed_for_current_region = 0;
 134       should_add_current_region = ParseSmapsHeader(smaps, &region);
 135     } else {
 136       counters_parsed_for_current_region += ParseSmapsCounter(smaps, &region);
 137       DCHECK_LE(counters_parsed_for_current_region,
 138                 kNumExpectedCountersPerRegion);
 139       if (counters_parsed_for_current_region == kNumExpectedCountersPerRegion) {
 140         if (should_add_current_region) {
 141           pmm->AddVMRegion(region);
 142           ++num_valid_regions;
 143           should_add_current_region = false;
 144         }
 145       }
 146     }
 147   }
 148   return num_valid_regions;
 149 }
 150
 151 }  // namespace
 152 #endif  // defined(OS_LINUX) || defined(OS_ANDROID)
 153
 154 // static
 155 ProcessMemoryMapsDumpProvider* ProcessMemoryMapsDumpProvider::GetInstance() {
 156   return Singleton<ProcessMemoryMapsDumpProvider,
 157                    LeakySingletonTraits<ProcessMemoryMapsDumpProvider>>::get();
 158 }
 159
 160 ProcessMemoryMapsDumpProvider::ProcessMemoryMapsDumpProvider() {
 161 }
 162
 163 ProcessMemoryMapsDumpProvider::~ProcessMemoryMapsDumpProvider() {
 164 }
 165
 166 // Called at trace dump point time. Creates a snapshot of the memory maps for
 167 // the current process.
 168 bool ProcessMemoryMapsDumpProvider::OnMemoryDump(const MemoryDumpArgs& args,
 169                                                  ProcessMemoryDump* pmd) {
 170   // Snapshot of memory maps is not taken for light dump requests.
 171   if (args.level_of_detail == MemoryDumpArgs::LevelOfDetail::LOW)
 172     return true;
 173
 174   uint32 res = 0;
 175
 176 #if defined(OS_LINUX) || defined(OS_ANDROID)
 177   if (UNLIKELY(proc_smaps_for_testing)) {
 178     res = ReadLinuxProcSmapsFile(proc_smaps_for_testing, pmd->process_mmaps());
 179   } else {
 180     std::ifstream proc_self_smaps("/proc/self/smaps");
 181     res = ReadLinuxProcSmapsFile(&proc_self_smaps, pmd->process_mmaps());
 182   }
 183 #else
 184   LOG(ERROR) << "ProcessMemoryMaps dump provider is supported only on Linux";
 185 #endif
 186
 187   if (res > 0) {
 188     pmd->set_has_process_mmaps();
 189     return true;
 190   }
 191
 192   return false;
 193 }
 194
 195 }  // namespace trace_event
 196 }  // namespace base