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
diff --git a/libunwindstack/Maps.cpp b/libunwindstack/Maps.cpp
new file mode 100644
index 0000000..b369c43
--- /dev/null
+++ b/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;
+}