Implement maps parsing.

The MapsOffline code is still in development so I'm not testing it very
thoroughly yet.

Bug: 23762183

Test: All unit tests pass.
Change-Id: I77aeac62940cd95c489ee221afe02349bfe39671

libunwindstack/Android.bp

@@ -54,6 +54,7 @@ cc_defaults {
         "ElfInterfaceArm.cpp",
         "Log.cpp",
         "Regs.cpp",
+        "Maps.cpp",
         "Memory.cpp",
         "Symbols.cpp",
     ],
@@ -97,6 +98,7 @@ cc_defaults {
         "tests/ElfInterfaceTest.cpp",
         "tests/ElfTest.cpp",
         "tests/LogFake.cpp",
+        "tests/MapsTest.cpp",
         "tests/MemoryFake.cpp",
         "tests/MemoryFileTest.cpp",
         "tests/MemoryLocalTest.cpp",

libunwindstack/Maps.cpp

@@ -0,0 +1,196 @@
+/*
+ * Copyright (C) 2016 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <errno.h>
+#include <fcntl.h>
+#include <inttypes.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <sys/mman.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+#include <android-base/unique_fd.h>
+
+#include <memory>
+#include <string>
+#include <vector>
+
+#include "Maps.h"
+
+MapInfo* Maps::Find(uint64_t pc) {
+  if (maps_.empty()) {
+    return nullptr;
+  }
+  size_t first = 0;
+  size_t last = maps_.size();
+  while (first < last) {
+    size_t index = (first + last) / 2;
+    MapInfo* cur = &maps_[index];
+    if (pc >= cur->start && pc < cur->end) {
+      return cur;
+    } else if (pc < cur->start) {
+      last = index;
+    } else {
+      first = index + 1;
+    }
+  }
+  return nullptr;
+}
+
+bool Maps::ParseLine(const char* line, MapInfo* map_info) {
+  char permissions[5];
+  int name_pos;
+  // Linux /proc/<pid>/maps lines:
+  // 6f000000-6f01e000 rwxp 00000000 00:0c 16389419   /system/lib/libcomposer.so
+  if (sscanf(line, "%" SCNx64 "-%" SCNx64 " %4s %" SCNx64 " %*x:%*x %*d %n", &map_info->start,
+             &map_info->end, permissions, &map_info->offset, &name_pos) != 4) {
+    return false;
+  }
+  map_info->flags = PROT_NONE;
+  if (permissions[0] == 'r') {
+    map_info->flags |= PROT_READ;
+  }
+  if (permissions[1] == 'w') {
+    map_info->flags |= PROT_WRITE;
+  }
+  if (permissions[2] == 'x') {
+    map_info->flags |= PROT_EXEC;
+  }
+
+  map_info->name = &line[name_pos];
+  size_t length = map_info->name.length() - 1;
+  if (map_info->name[length] == '\n') {
+    map_info->name.erase(length);
+  }
+  // Mark a device map in /dev/and not in /dev/ashmem/ specially.
+  if (!map_info->name.empty() && map_info->name.substr(0, 5) == "/dev/" &&
+      map_info->name.substr(5, 7) != "ashmem/") {
+    map_info->flags |= MAPS_FLAGS_DEVICE_MAP;
+  }
+
+  return true;
+}
+
+bool Maps::Parse() {
+  std::unique_ptr<FILE, decltype(&fclose)> fp(fopen(GetMapsFile().c_str(), "re"), fclose);
+  if (!fp) {
+    return false;
+  }
+
+  bool valid = true;
+  char* line = nullptr;
+  size_t line_len;
+  while (getline(&line, &line_len, fp.get()) > 0) {
+    MapInfo map_info;
+    if (!ParseLine(line, &map_info)) {
+      valid = false;
+      break;
+    }
+
+    maps_.push_back(map_info);
+  }
+  free(line);
+
+  return valid;
+}
+
+Maps::~Maps() {
+  for (auto& map : maps_) {
+    delete map.elf;
+    map.elf = nullptr;
+  }
+}
+
+bool BufferMaps::Parse() {
+  const char* start_of_line = buffer_;
+  do {
+    std::string line;
+    const char* end_of_line = strchr(start_of_line, '\n');
+    if (end_of_line == nullptr) {
+      line = start_of_line;
+    } else {
+      end_of_line++;
+      line = std::string(start_of_line, end_of_line - start_of_line);
+    }
+
+    MapInfo map_info;
+    if (!ParseLine(line.c_str(), &map_info)) {
+      return false;
+    }
+    maps_.push_back(map_info);
+
+    start_of_line = end_of_line;
+  } while (start_of_line != nullptr && *start_of_line != '\0');
+  return true;
+}
+
+const std::string RemoteMaps::GetMapsFile() const {
+  return "/proc/" + std::to_string(pid_) + "/maps";
+}
+
+bool OfflineMaps::Parse() {
+  // Format of maps information:
+  //   <uint64_t> StartOffset
+  //   <uint64_t> EndOffset
+  //   <uint64_t> offset
+  //   <uint16_t> flags
+  //   <uint16_t> MapNameLength
+  //   <VariableLengthValue> MapName
+  android::base::unique_fd fd(TEMP_FAILURE_RETRY(open(file_.c_str(), O_RDONLY)));
+  if (fd == -1) {
+    return false;
+  }
+
+  std::vector<char> name;
+  while (true) {
+    MapInfo map_info;
+    ssize_t bytes = TEMP_FAILURE_RETRY(read(fd, &map_info.start, sizeof(map_info.start)));
+    if (bytes == 0) {
+      break;
+    }
+    if (bytes == -1 || bytes != sizeof(map_info.start)) {
+      return false;
+    }
+    bytes = TEMP_FAILURE_RETRY(read(fd, &map_info.end, sizeof(map_info.end)));
+    if (bytes == -1 || bytes != sizeof(map_info.end)) {
+      return false;
+    }
+    bytes = TEMP_FAILURE_RETRY(read(fd, &map_info.offset, sizeof(map_info.offset)));
+    if (bytes == -1 || bytes != sizeof(map_info.offset)) {
+      return false;
+    }
+    bytes = TEMP_FAILURE_RETRY(read(fd, &map_info.flags, sizeof(map_info.flags)));
+    if (bytes == -1 || bytes != sizeof(map_info.flags)) {
+      return false;
+    }
+    uint16_t len;
+    bytes = TEMP_FAILURE_RETRY(read(fd, &len, sizeof(len)));
+    if (bytes == -1 || bytes != sizeof(len)) {
+      return false;
+    }
+    if (len > 0) {
+      name.resize(len);
+      bytes = TEMP_FAILURE_RETRY(read(fd, name.data(), len));
+      if (bytes == -1 || bytes != len) {
+        return false;
+      }
+      map_info.name = std::string(name.data(), len);
+    }
+    maps_.push_back(map_info);
+  }
+  return true;
+}

libunwindstack/Maps.h

@@ -0,0 +1,107 @@
+/*
+ * Copyright (C) 2016 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef _LIBUNWINDSTACK_MAPS_H
+#define _LIBUNWINDSTACK_MAPS_H
+
+#include <sys/types.h>
+#include <unistd.h>
+
+#include <string>
+#include <vector>
+
+#include "Elf.h"
+#include "MapInfo.h"
+
+// Special flag to indicate a map is in /dev/. However, a map in
+// /dev/ashmem/... does not set this flag.
+static constexpr int MAPS_FLAGS_DEVICE_MAP = 0x8000;
+
+class Maps {
+ public:
+  Maps() = default;
+  virtual ~Maps();
+
+  MapInfo* Find(uint64_t pc);
+
+  bool ParseLine(const char* line, MapInfo* map_info);
+
+  virtual bool Parse();
+
+  virtual const std::string GetMapsFile() const { return ""; }
+
+  typedef std::vector<MapInfo>::iterator iterator;
+  iterator begin() { return maps_.begin(); }
+  iterator end() { return maps_.end(); }
+
+  typedef std::vector<MapInfo>::const_iterator const_iterator;
+  const_iterator begin() const { return maps_.begin(); }
+  const_iterator end() const { return maps_.end(); }
+
+  size_t Total() { return maps_.size(); }
+
+ protected:
+  std::vector<MapInfo> maps_;
+};
+
+class RemoteMaps : public Maps {
+ public:
+  RemoteMaps(pid_t pid) : pid_(pid) {}
+  virtual ~RemoteMaps() = default;
+
+  virtual const std::string GetMapsFile() const override;
+
+ private:
+  pid_t pid_;
+};
+
+class LocalMaps : public RemoteMaps {
+ public:
+  LocalMaps() : RemoteMaps(getpid()) {}
+  virtual ~LocalMaps() = default;
+};
+
+class BufferMaps : public Maps {
+ public:
+  BufferMaps(const char* buffer) : buffer_(buffer) {}
+  virtual ~BufferMaps() = default;
+
+  bool Parse() override;
+
+ private:
+  const char* buffer_;
+};
+
+class FileMaps : public Maps {
+ public:
+  FileMaps(const std::string& file) : file_(file) {}
+  virtual ~FileMaps() = default;
+
+  const std::string GetMapsFile() const override { return file_; }
+
+ protected:
+  const std::string file_;
+};
+
+class OfflineMaps : public FileMaps {
+ public:
+  OfflineMaps(const std::string& file) : FileMaps(file) {}
+  virtual ~OfflineMaps() = default;
+
+  bool Parse() override;
+};
+
+#endif  // _LIBUNWINDSTACK_MAPS_H

libunwindstack/tests/MapsTest.cpp

@@ -0,0 +1,237 @@
+/*
+ * Copyright (C) 2016 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <sys/mman.h>
+
+#include <android-base/file.h>
+#include <android-base/test_utils.h>
+#include <gtest/gtest.h>
+
+#include "Maps.h"
+
+TEST(MapsTest, parse_permissions) {
+  BufferMaps maps(
+      "1000-2000 ---- 00000000 00:00 0\n"
+      "2000-3000 r--- 00000000 00:00 0\n"
+      "3000-4000 -w-- 00000000 00:00 0\n"
+      "4000-5000 --x- 00000000 00:00 0\n"
+      "5000-6000 rwx- 00000000 00:00 0\n");
+
+  ASSERT_TRUE(maps.Parse());
+  ASSERT_EQ(5U, maps.Total());
+  auto it = maps.begin();
+  ASSERT_EQ(PROT_NONE, it->flags);
+  ASSERT_EQ(0x1000U, it->start);
+  ASSERT_EQ(0x2000U, it->end);
+  ASSERT_EQ(0U, it->offset);
+  ASSERT_EQ("", it->name);
+  ++it;
+  ASSERT_EQ(PROT_READ, it->flags);
+  ASSERT_EQ(0x2000U, it->start);
+  ASSERT_EQ(0x3000U, it->end);
+  ASSERT_EQ(0U, it->offset);
+  ASSERT_EQ("", it->name);
+  ++it;
+  ASSERT_EQ(PROT_WRITE, it->flags);
+  ASSERT_EQ(0x3000U, it->start);
+  ASSERT_EQ(0x4000U, it->end);
+  ASSERT_EQ(0U, it->offset);
+  ASSERT_EQ("", it->name);
+  ++it;
+  ASSERT_EQ(PROT_EXEC, it->flags);
+  ASSERT_EQ(0x4000U, it->start);
+  ASSERT_EQ(0x5000U, it->end);
+  ASSERT_EQ(0U, it->offset);
+  ASSERT_EQ("", it->name);
+  ++it;
+  ASSERT_EQ(PROT_READ | PROT_WRITE | PROT_EXEC, it->flags);
+  ASSERT_EQ(0x5000U, it->start);
+  ASSERT_EQ(0x6000U, it->end);
+  ASSERT_EQ(0U, it->offset);
+  ASSERT_EQ("", it->name);
+  ++it;
+  ASSERT_EQ(it, maps.end());
+}
+
+TEST(MapsTest, parse_name) {
+  BufferMaps maps(
+      "720b29b000-720b29e000 rw-p 00000000 00:00 0\n"
+      "720b29e000-720b29f000 rw-p 00000000 00:00 0 /system/lib/fake.so\n"
+      "720b29f000-720b2a0000 rw-p 00000000 00:00 0");
+
+  ASSERT_TRUE(maps.Parse());
+  ASSERT_EQ(3U, maps.Total());
+  auto it = maps.begin();
+  ASSERT_EQ("", it->name);
+  ASSERT_EQ(0x720b29b000U, it->start);
+  ASSERT_EQ(0x720b29e000U, it->end);
+  ASSERT_EQ(0U, it->offset);
+  ASSERT_EQ(PROT_READ | PROT_WRITE, it->flags);
+  ++it;
+  ASSERT_EQ("/system/lib/fake.so", it->name);
+  ASSERT_EQ(0x720b29e000U, it->start);
+  ASSERT_EQ(0x720b29f000U, it->end);
+  ASSERT_EQ(0U, it->offset);
+  ASSERT_EQ(PROT_READ | PROT_WRITE, it->flags);
+  ++it;
+  ASSERT_EQ("", it->name);
+  ASSERT_EQ(0x720b29f000U, it->start);
+  ASSERT_EQ(0x720b2a0000U, it->end);
+  ASSERT_EQ(0U, it->offset);
+  ASSERT_EQ(PROT_READ | PROT_WRITE, it->flags);
+  ++it;
+  ASSERT_EQ(it, maps.end());
+}
+
+TEST(MapsTest, parse_offset) {
+  BufferMaps maps(
+      "a000-e000 rw-p 00000000 00:00 0 /system/lib/fake.so\n"
+      "e000-f000 rw-p 00a12345 00:00 0 /system/lib/fake.so\n");
+
+  ASSERT_TRUE(maps.Parse());
+  ASSERT_EQ(2U, maps.Total());
+  auto it = maps.begin();
+  ASSERT_EQ(0U, it->offset);
+  ASSERT_EQ(0xa000U, it->start);
+  ASSERT_EQ(0xe000U, it->end);
+  ASSERT_EQ(PROT_READ | PROT_WRITE, it->flags);
+  ASSERT_EQ("/system/lib/fake.so", it->name);
+  ++it;
+  ASSERT_EQ(0xa12345U, it->offset);
+  ASSERT_EQ(0xe000U, it->start);
+  ASSERT_EQ(0xf000U, it->end);
+  ASSERT_EQ(PROT_READ | PROT_WRITE, it->flags);
+  ASSERT_EQ("/system/lib/fake.so", it->name);
+  ++it;
+  ASSERT_EQ(maps.end(), it);
+}
+
+TEST(MapsTest, device) {
+  BufferMaps maps(
+      "a000-e000 rw-p 00000000 00:00 0 /dev/\n"
+      "f000-f100 rw-p 00000000 00:00 0 /dev/does_not_exist\n"
+      "f100-f200 rw-p 00000000 00:00 0 /dev/ashmem/does_not_exist\n"
+      "f200-f300 rw-p 00000000 00:00 0 /devsomething/does_not_exist\n");
+
+  ASSERT_TRUE(maps.Parse());
+  ASSERT_EQ(4U, maps.Total());
+  auto it = maps.begin();
+  ASSERT_TRUE(it->flags & 0x8000);
+  ASSERT_EQ("/dev/", it->name);
+  ++it;
+  ASSERT_TRUE(it->flags & 0x8000);
+  ASSERT_EQ("/dev/does_not_exist", it->name);
+  ++it;
+  ASSERT_FALSE(it->flags & 0x8000);
+  ASSERT_EQ("/dev/ashmem/does_not_exist", it->name);
+  ++it;
+  ASSERT_FALSE(it->flags & 0x8000);
+  ASSERT_EQ("/devsomething/does_not_exist", it->name);
+}
+
+TEST(MapsTest, file_smoke) {
+  TemporaryFile tf;
+  ASSERT_TRUE(tf.fd != -1);
+
+  ASSERT_TRUE(
+      android::base::WriteStringToFile("720b29b000-720b29e000 r-xp a0000000 00:00 0   /fake.so\n"
+                                       "720b2b0000-720b2e0000 r-xp b0000000 00:00 0   /fake2.so\n"
+                                       "720b2e0000-720b2f0000 r-xp c0000000 00:00 0   /fake3.so\n",
+                                       tf.path, 0660, getuid(), getgid()));
+
+  FileMaps maps(tf.path);
+
+  ASSERT_TRUE(maps.Parse());
+  ASSERT_EQ(3U, maps.Total());
+  auto it = maps.begin();
+  ASSERT_EQ(0x720b29b000U, it->start);
+  ASSERT_EQ(0x720b29e000U, it->end);
+  ASSERT_EQ(0xa0000000U, it->offset);
+  ASSERT_EQ(PROT_READ | PROT_EXEC, it->flags);
+  ASSERT_EQ("/fake.so", it->name);
+  ++it;
+  ASSERT_EQ(0x720b2b0000U, it->start);
+  ASSERT_EQ(0x720b2e0000U, it->end);
+  ASSERT_EQ(0xb0000000U, it->offset);
+  ASSERT_EQ(PROT_READ | PROT_EXEC, it->flags);
+  ASSERT_EQ("/fake2.so", it->name);
+  ++it;
+  ASSERT_EQ(0x720b2e0000U, it->start);
+  ASSERT_EQ(0x720b2f0000U, it->end);
+  ASSERT_EQ(0xc0000000U, it->offset);
+  ASSERT_EQ(PROT_READ | PROT_EXEC, it->flags);
+  ASSERT_EQ("/fake3.so", it->name);
+  ++it;
+  ASSERT_EQ(it, maps.end());
+}
+
+TEST(MapsTest, find) {
+  BufferMaps maps(
+      "1000-2000 r--p 00000010 00:00 0 /system/lib/fake1.so\n"
+      "3000-4000 -w-p 00000020 00:00 0 /system/lib/fake2.so\n"
+      "6000-8000 --xp 00000030 00:00 0 /system/lib/fake3.so\n"
+      "a000-b000 rw-p 00000040 00:00 0 /system/lib/fake4.so\n"
+      "e000-f000 rwxp 00000050 00:00 0 /system/lib/fake5.so\n");
+  ASSERT_TRUE(maps.Parse());
+  ASSERT_EQ(5U, maps.Total());
+
+  ASSERT_TRUE(maps.Find(0x500) == nullptr);
+  ASSERT_TRUE(maps.Find(0x2000) == nullptr);
+  ASSERT_TRUE(maps.Find(0x5010) == nullptr);
+  ASSERT_TRUE(maps.Find(0x9a00) == nullptr);
+  ASSERT_TRUE(maps.Find(0xf000) == nullptr);
+  ASSERT_TRUE(maps.Find(0xf010) == nullptr);
+
+  MapInfo* info = maps.Find(0x1000);
+  ASSERT_TRUE(info != nullptr);
+  ASSERT_EQ(0x1000U, info->start);
+  ASSERT_EQ(0x2000U, info->end);
+  ASSERT_EQ(0x10U, info->offset);
+  ASSERT_EQ(PROT_READ, info->flags);
+  ASSERT_EQ("/system/lib/fake1.so", info->name);
+
+  info = maps.Find(0x3020);
+  ASSERT_TRUE(info != nullptr);
+  ASSERT_EQ(0x3000U, info->start);
+  ASSERT_EQ(0x4000U, info->end);
+  ASSERT_EQ(0x20U, info->offset);
+  ASSERT_EQ(PROT_WRITE, info->flags);
+  ASSERT_EQ("/system/lib/fake2.so", info->name);
+
+  info = maps.Find(0x6020);
+  ASSERT_TRUE(info != nullptr);
+  ASSERT_EQ(0x6000U, info->start);
+  ASSERT_EQ(0x8000U, info->end);
+  ASSERT_EQ(0x30U, info->offset);
+  ASSERT_EQ(PROT_EXEC, info->flags);
+  ASSERT_EQ("/system/lib/fake3.so", info->name);
+
+  info = maps.Find(0xafff);
+  ASSERT_TRUE(info != nullptr);
+  ASSERT_EQ(0xa000U, info->start);
+  ASSERT_EQ(0xb000U, info->end);
+  ASSERT_EQ(0x40U, info->offset);
+  ASSERT_EQ(PROT_READ | PROT_WRITE, info->flags);
+  ASSERT_EQ("/system/lib/fake4.so", info->name);
+
+  info = maps.Find(0xe500);
+  ASSERT_TRUE(info != nullptr);
+  ASSERT_EQ(0xe000U, info->start);
+  ASSERT_EQ(0xf000U, info->end);
+  ASSERT_EQ(0x50U, info->offset);
+  ASSERT_EQ(PROT_READ | PROT_WRITE | PROT_EXEC, info->flags);
+  ASSERT_EQ("/system/lib/fake5.so", info->name);
+}