platform_system_core/libbacktrace/BacktraceMap.cpp

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/*
* Copyright (C) 2014 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.
*/
#define LOG_TAG "backtrace-map"
#include <ctype.h>
#include <inttypes.h>
#include <stdint.h>
#include <sys/types.h>
#include <unistd.h>
#include <log/log.h>
#include <android-base/stringprintf.h>
#include <backtrace/Backtrace.h>
#include <backtrace/BacktraceMap.h>
#include <backtrace/backtrace_constants.h>
#if defined(__linux__)
#include <procinfo/process_map.h>
#endif
using android::base::StringPrintf;
std::string backtrace_map_t::Name() const {
if (!name.empty()) return name;
if (start == 0 && end == 0) return "";
return StringPrintf("<anonymous:%" PRIPTR ">", start);
}
BacktraceMap::BacktraceMap(pid_t pid) : pid_(pid) {
if (pid_ < 0) {
pid_ = getpid();
}
}
BacktraceMap::~BacktraceMap() {}
void BacktraceMap::FillIn(uint64_t addr, backtrace_map_t* map) {
ScopedBacktraceMapIteratorLock lock(this);
for (auto it = begin(); it != end(); ++it) {
const backtrace_map_t* entry = *it;
if (addr >= entry->start && addr < entry->end) {
*map = *entry;
return;
}
}
*map = {};
}
#if defined(__APPLE__)
static bool ParseLine(const char* line, backtrace_map_t* map) {
uint64_t start;
uint64_t end;
char permissions[5];
int name_pos;
// Mac OS vmmap(1) output:
// __TEXT 0009f000-000a1000 [ 8K 8K] r-x/rwx SM=COW
// /Volumes/android/dalvik-dev/out/host/darwin-x86/bin/libcorkscrew_test\n
// 012345678901234567890123456789012345678901234567890123456789
// 0 1 2 3 4 5
if (sscanf(line, "%*21c %" SCNx64 "-%" SCNx64 " [%*13c] %3c/%*3c SM=%*3c %n", &start, &end,
permissions, &name_pos) != 3) {
return false;
}
map->start = start;
map->end = end;
map->flags = PROT_NONE;
if (permissions[0] == 'r') {
map->flags |= PROT_READ;
}
if (permissions[1] == 'w') {
map->flags |= PROT_WRITE;
}
if (permissions[2] == 'x') {
map->flags |= PROT_EXEC;
}
map->name = line + name_pos;
if (!map->name.empty() && map->name[map->name.length() - 1] == '\n') {
map->name.erase(map->name.length() - 1);
}
ALOGV("Parsed map: start=%p, end=%p, flags=%x, name=%s", reinterpret_cast<void*>(map->start),
reinterpret_cast<void*>(map->end), map->flags, map->name.c_str());
return true;
}
#endif // defined(__APPLE__)
bool BacktraceMap::Build() {
#if defined(__APPLE__)
char
cmd[sizeof(pid_t) * 3 + sizeof("vmmap -w -resident -submap -allSplitLibs -interleaved ") + 1];
char line[1024];
// cmd is guaranteed to always be big enough to hold this string.
snprintf(cmd, sizeof(cmd), "vmmap -w -resident -submap -allSplitLibs -interleaved %d", pid_);
FILE* fp = popen(cmd, "r");
if (fp == nullptr) {
return false;
}
while (fgets(line, sizeof(line), fp)) {
backtrace_map_t map;
if (ParseLine(line, &map)) {
maps_.push_back(map);
}
}
pclose(fp);
return true;
#else
return android::procinfo::ReadProcessMaps(
pid_, [&](uint64_t start, uint64_t end, uint16_t flags, uint64_t, ino_t, const char* name) {
maps_.resize(maps_.size() + 1);
backtrace_map_t& map = maps_.back();
map.start = start;
map.end = end;
map.flags = flags;
map.name = name;
});
#endif
}
#if defined(__APPLE__)
// Corkscrew and libunwind don't compile on the mac, so create a generic
// map object.
BacktraceMap* BacktraceMap::Create(pid_t pid, bool /*uncached*/) {
BacktraceMap* map = new BacktraceMap(pid);
if (!map->Build()) {
delete map;
return nullptr;
}
return map;
}
#endif