[tracing] Add memory maps dumper impl for Linux/Android

This is a follow-up to crrev.com/928723004. It introduces
the code which is able to read and parse the /proc/.../smaps
file into an actual TraceValue and the corresponding unittest.

BUG=460884

Review URL: https://codereview.chromium.org/951463002

Cr-Commit-Position: refs/heads/master@{#318023}

2 files changed, 246 insertions, 5 deletions

diff --git a/base/trace_event/process_memory_maps_dump_provider.cc b/base/trace_event/process_memory_maps_dump_provider.cc
index b6fba80..e1cefc3 100644
--- a/base/trace_event/process_memory_maps_dump_provider.cc
+++ b/base/trace_event/process_memory_maps_dump_provider.cc
@@ -4,6 +4,7 @@
 
 #include "base/trace_event/process_memory_maps_dump_provider.h"
 
+#include <cctype>
 #include <fstream>
 
 #include "base/logging.h"
@@ -19,15 +20,123 @@ namespace trace_event {
 std::istream* ProcessMemoryMapsDumpProvider::proc_smaps_for_testing = nullptr;
 
 namespace {
+
+const uint32 kMaxLineSize = 4096;
+
+bool ParseSmapsHeader(std::istream* smaps,
+                      ProcessMemoryMaps::VMRegion* region) {
+  // e.g., "00400000-00421000 r-xp 00000000 fc:01 1234  /foo.so\n"
+  bool res = true;  // Whether this region should be appended or skipped.
+  uint64 end_addr;
+  std::string protection_flags;
+  std::string ignored;
+  *smaps >> std::hex >> region->start_address;
+  smaps->ignore(1);
+  *smaps >> std::hex >> end_addr;
+  if (end_addr > region->start_address) {
+    region->size_in_bytes = end_addr - region->start_address;
+  } else {
+    // This is not just paranoia, it can actually happen (See crbug.com/461237).
+    region->size_in_bytes = 0;
+    res = false;
+  }
+
+  region->protection_flags = 0;
+  *smaps >> protection_flags;
+  CHECK(4UL == protection_flags.size());
+  if (protection_flags[0] == 'r') {
+    region->protection_flags |=
+        ProcessMemoryMaps::VMRegion::kProtectionFlagsRead;
+  }
+  if (protection_flags[1] == 'w') {
+    region->protection_flags |=
+        ProcessMemoryMaps::VMRegion::kProtectionFlagsWrite;
+  }
+  if (protection_flags[2] == 'x') {
+    region->protection_flags |=
+        ProcessMemoryMaps::VMRegion::kProtectionFlagsExec;
+  }
+  *smaps >> std::hex >> region->mapped_file_offset;
+  *smaps >> ignored;  // Ignore device maj-min (fc:01 in the example above).
+  *smaps >> ignored;  // Ignore inode number (1234 in the example above).
+
+  while (smaps->peek() == ' ')
+    smaps->ignore(1);
+  char mapped_file[kMaxLineSize];
+  smaps->getline(mapped_file, sizeof(mapped_file));
+  region->mapped_file = mapped_file;
+
+  return res;
+}
+
+uint32 ParseSmapsCounter(std::istream* smaps,
+                         ProcessMemoryMaps::VMRegion* region) {
+  // e.g., "RSS:  0 Kb\n"
+  uint32 res = 0;
+  std::string counter_name;
+  *smaps >> counter_name;
+
+  // TODO(primiano): "Swap" should also be accounted as resident. Check
+  // whether Rss isn't already counting swapped and fix below if that is
+  // the case.
+  if (counter_name == "Rss:") {
+    *smaps >> std::dec >> region->byte_stats_resident;
+    region->byte_stats_resident *= 1024;
+    res = 1;
+  } else if (counter_name == "Anonymous:") {
+    *smaps >> std::dec >> region->byte_stats_anonymous;
+    region->byte_stats_anonymous *= 1024;
+    res = 1;
+  }
+
+#ifndef NDEBUG
+  // Paranoid check against changes of the Kernel /proc interface.
+  if (res) {
+    std::string unit;
+    *smaps >> unit;
+    DCHECK_EQ("kB", unit);
+  }
+#endif
+
+  smaps->ignore(kMaxLineSize, '\n');
+
+  return res;
+}
+
 uint32 ReadLinuxProcSmapsFile(std::istream* smaps, ProcessMemoryMaps* pmm) {
   if (!smaps->good()) {
     LOG(ERROR) << "Could not read smaps file.";
     return 0;
   }
-  uint32 num_regions_processed = 0;
-  // TODO(primiano): in next CLs add the actual code to process the smaps file.
-  return num_regions_processed;
+  const uint32 kNumExpectedCountersPerRegion = 2;
+  uint32 counters_parsed_for_current_region = 0;
+  uint32 num_valid_regions = 0;
+  ProcessMemoryMaps::VMRegion region;
+  bool should_add_current_region = false;
+  for (;;) {
+    int next = smaps->peek();
+    if (next == std::ifstream::traits_type::eof() || next == '\n')
+      break;
+    if (isxdigit(next) && !isupper(next)) {
+      region = {0};
+      counters_parsed_for_current_region = 0;
+      should_add_current_region = ParseSmapsHeader(smaps, &region);
+    } else {
+      counters_parsed_for_current_region += ParseSmapsCounter(smaps, &region);
+      DCHECK_LE(counters_parsed_for_current_region,
+                kNumExpectedCountersPerRegion);
+      if (counters_parsed_for_current_region == kNumExpectedCountersPerRegion) {
+        if (should_add_current_region) {
+          pmm->AddVMRegion(region);
+          ++num_valid_regions;
+          should_add_current_region = false;
+        }
+      }
+    }
+  }
+  return num_valid_regions;
 }
+
 }  // namespace
 #endif  // defined(OS_LINUX) || defined(OS_ANDROID)
 
diff --git a/base/trace_event/process_memory_maps_dump_provider_unittest.cc b/base/trace_event/process_memory_maps_dump_provider_unittest.cc
index 33c1bbb..02fd136 100644
--- a/base/trace_event/process_memory_maps_dump_provider_unittest.cc
+++ b/base/trace_event/process_memory_maps_dump_provider_unittest.cc
@@ -16,7 +16,101 @@ namespace base {
 namespace trace_event {
 
 #if defined(OS_LINUX) || defined(OS_ANDROID)
+namespace {
+const char kTestSmaps1[] =
+    "00400000-004be000 r-xp 00000000 fc:01 1234              /file/1\n"
+    "Size:                760 kB\n"
+    "Rss:                 296 kB\n"
+    "Pss:                 162 kB\n"
+    "Shared_Clean:        228 kB\n"
+    "Shared_Dirty:          0 kB\n"
+    "Private_Clean:         0 kB\n"
+    "Private_Dirty:        68 kB\n"
+    "Referenced:          296 kB\n"
+    "Anonymous:            68 kB\n"
+    "AnonHugePages:         0 kB\n"
+    "Swap:                  0 kB\n"
+    "KernelPageSize:        4 kB\n"
+    "MMUPageSize:           4 kB\n"
+    "Locked:                0 kB\n"
+    "VmFlags: rd ex mr mw me dw sd\n"
+    "ff000000-ff800000 -w-p 00001080 fc:01 0            /file/name with space\n"
+    "Size:                  0 kB\n"
+    "Rss:                 128 kB\n"
+    "Pss:                 128 kB\n"
+    "Shared_Clean:        124 kB\n"
+    "Shared_Dirty:          0 kB\n"
+    "Private_Clean:        68 kB\n"
+    "Private_Dirty:         0 kB\n"
+    "Referenced:          296 kB\n"
+    "Anonymous:             0 kB\n"
+    "AnonHugePages:         0 kB\n"
+    "Swap:                  0 kB\n"
+    "KernelPageSize:        4 kB\n"
+    "MMUPageSize:           4 kB\n"
+    "Locked:                0 kB\n"
+    "VmFlags: rd ex mr mw me dw sd";
+
+const char kTestSmaps2[] =
+    // An invalid region, with zero size and overlapping with the last one
+    // (See crbug.com/461237).
+    "7fe7ce79c000-7fe7ce79c000 ---p 00000000 00:00 0 \n"
+    "Size:                  4 kB\n"
+    "Rss:                   0 kB\n"
+    "Pss:                   0 kB\n"
+    "Shared_Clean:          0 kB\n"
+    "Shared_Dirty:          0 kB\n"
+    "Private_Clean:         0 kB\n"
+    "Private_Dirty:         0 kB\n"
+    "Referenced:            0 kB\n"
+    "Anonymous:             0 kB\n"
+    "AnonHugePages:         0 kB\n"
+    "Swap:                  0 kB\n"
+    "KernelPageSize:        4 kB\n"
+    "MMUPageSize:           4 kB\n"
+    "Locked:                0 kB\n"
+    "VmFlags: rd ex mr mw me dw sd\n"
+    // A invalid region with its range going backwards.
+    "00400000-00200000 ---p 00000000 00:00 0 \n"
+    "Size:                  4 kB\n"
+    "Rss:                   0 kB\n"
+    "Pss:                   0 kB\n"
+    "Shared_Clean:          0 kB\n"
+    "Shared_Dirty:          0 kB\n"
+    "Private_Clean:         0 kB\n"
+    "Private_Dirty:         0 kB\n"
+    "Referenced:            0 kB\n"
+    "Anonymous:             0 kB\n"
+    "AnonHugePages:         0 kB\n"
+    "Swap:                  0 kB\n"
+    "KernelPageSize:        4 kB\n"
+    "MMUPageSize:           4 kB\n"
+    "Locked:                0 kB\n"
+    "VmFlags: rd ex mr mw me dw sd\n"
+    // A good anonymous region at the end.
+    "7fe7ce79c000-7fe7ce7a8000 ---p 00000000 00:00 0 \n"
+    "Size:                 48 kB\n"
+    "Rss:                  40 kB\n"
+    "Pss:                   0 kB\n"
+    "Shared_Clean:         16 kB\n"
+    "Shared_Dirty:         12 kB\n"
+    "Private_Clean:         8 kB\n"
+    "Private_Dirty:         4 kB\n"
+    "Referenced:           40 kB\n"
+    "Anonymous:            16 kB\n"
+    "AnonHugePages:         0 kB\n"
+    "Swap:                  0 kB\n"
+    "KernelPageSize:        4 kB\n"
+    "MMUPageSize:           4 kB\n"
+    "Locked:                0 kB\n"
+    "VmFlags: rd wr mr mw me ac sd\n";
+}  // namespace
+
 TEST(ProcessMemoryMapsDumpProviderTest, ParseProcSmaps) {
+  const uint32 kProtR = ProcessMemoryMaps::VMRegion::kProtectionFlagsRead;
+  const uint32 kProtW = ProcessMemoryMaps::VMRegion::kProtectionFlagsWrite;
+  const uint32 kProtX = ProcessMemoryMaps::VMRegion::kProtectionFlagsExec;
+
   auto pmmdp = ProcessMemoryMapsDumpProvider::GetInstance();
 
   // Emulate a non-existent /proc/self/smaps.
@@ -34,8 +128,46 @@ TEST(ProcessMemoryMapsDumpProviderTest, ParseProcSmaps) {
   pmmdp->DumpInto(&pmd_invalid);
   ASSERT_FALSE(pmd_invalid.has_process_mmaps());
 
-  // TODO(primiano): in the next CLs add the code to parse some actual smaps
-  // files and check that the parsing logic of the dump provider holds.
+  // Parse the 1st smaps file.
+  ProcessMemoryDump pmd_1;
+  std::istringstream test_smaps_1(kTestSmaps1);
+  ProcessMemoryMapsDumpProvider::proc_smaps_for_testing = &test_smaps_1;
+  pmmdp->DumpInto(&pmd_1);
+  ASSERT_TRUE(pmd_1.has_process_mmaps());
+  const auto& regions_1 = pmd_1.process_mmaps()->vm_regions();
+  ASSERT_EQ(2UL, regions_1.size());
+
+  EXPECT_EQ(0x00400000UL, regions_1[0].start_address);
+  EXPECT_EQ(0x004be000UL - 0x00400000UL, regions_1[0].size_in_bytes);
+  EXPECT_EQ(kProtR | kProtX, regions_1[0].protection_flags);
+  EXPECT_EQ("/file/1", regions_1[0].mapped_file);
+  EXPECT_EQ(0UL, regions_1[0].mapped_file_offset);
+  EXPECT_EQ(296 * 1024UL, regions_1[0].byte_stats_resident);
+  EXPECT_EQ(68 * 1024UL, regions_1[0].byte_stats_anonymous);
+
+  EXPECT_EQ(0xff000000UL, regions_1[1].start_address);
+  EXPECT_EQ(0xff800000UL - 0xff000000UL, regions_1[1].size_in_bytes);
+  EXPECT_EQ(kProtW, regions_1[1].protection_flags);
+  EXPECT_EQ("/file/name with space", regions_1[1].mapped_file);
+  EXPECT_EQ(0x00001080UL, regions_1[1].mapped_file_offset);
+  EXPECT_EQ(128 * 1024UL, regions_1[1].byte_stats_resident);
+  EXPECT_EQ(0UL, regions_1[1].byte_stats_anonymous);
+
+  // Parse the 2nd smaps file.
+  ProcessMemoryDump pmd_2;
+  std::istringstream test_smaps_2(kTestSmaps2);
+  ProcessMemoryMapsDumpProvider::proc_smaps_for_testing = &test_smaps_2;
+  pmmdp->DumpInto(&pmd_2);
+  ASSERT_TRUE(pmd_2.has_process_mmaps());
+  const auto& regions_2 = pmd_2.process_mmaps()->vm_regions();
+  ASSERT_EQ(1UL, regions_2.size());
+  EXPECT_EQ(0x7fe7ce79c000UL, regions_2[0].start_address);
+  EXPECT_EQ(0x7fe7ce7a8000UL - 0x7fe7ce79c000UL, regions_2[0].size_in_bytes);
+  EXPECT_EQ(0U, regions_2[0].protection_flags);
+  EXPECT_EQ("", regions_2[0].mapped_file);
+  EXPECT_EQ(0UL, regions_2[0].mapped_file_offset);
+  EXPECT_EQ(40 * 1024UL, regions_2[0].byte_stats_resident);
+  EXPECT_EQ(16 * 1024UL, regions_2[0].byte_stats_anonymous);
 }
 #endif  // defined(OS_LINUX) || defined(OS_ANDROID)