New version of unwinder.
Bug: 23762183
Test: All unit tests pass.
Change-Id: I0ac69e55af56e1142c0a1ee3715cdc48f2ed3ec3
diff --git a/libunwindstack/Memory.cpp b/libunwindstack/Memory.cpp
new file mode 100644
index 0000000..336e4fe
--- /dev/null
+++ b/libunwindstack/Memory.cpp
@@ -0,0 +1,180 @@
+/*
+ * 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 <sys/mman.h>
+#include <sys/ptrace.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <sys/uio.h>
+#include <unistd.h>
+
+#include <algorithm>
+#include <memory>
+
+#include <android-base/unique_fd.h>
+
+#include "Memory.h"
+
+bool Memory::ReadString(uint64_t addr, std::string* string, uint64_t max_read) {
+ string->clear();
+ uint64_t bytes_read = 0;
+ while (bytes_read < max_read) {
+ uint8_t value;
+ if (!Read(addr, &value, sizeof(value))) {
+ return false;
+ }
+ if (value == '\0') {
+ return true;
+ }
+ string->push_back(value);
+ addr++;
+ bytes_read++;
+ }
+ return false;
+}
+
+MemoryFileAtOffset::~MemoryFileAtOffset() {
+ if (data_) {
+ munmap(&data_[-offset_], size_ + offset_);
+ data_ = nullptr;
+ }
+}
+
+bool MemoryFileAtOffset::Init(const std::string& file, uint64_t offset) {
+ android::base::unique_fd fd(TEMP_FAILURE_RETRY(open(file.c_str(), O_RDONLY | O_CLOEXEC)));
+ if (fd == -1) {
+ return false;
+ }
+ struct stat buf;
+ if (fstat(fd, &buf) == -1) {
+ return false;
+ }
+ if (offset >= static_cast<uint64_t>(buf.st_size)) {
+ return false;
+ }
+
+ offset_ = offset & (getpagesize() - 1);
+ uint64_t aligned_offset = offset & ~(getpagesize() - 1);
+ size_ = buf.st_size - aligned_offset;
+ void* map = mmap(nullptr, size_, PROT_READ, MAP_PRIVATE, fd, aligned_offset);
+ if (map == MAP_FAILED) {
+ return false;
+ }
+
+ data_ = &reinterpret_cast<uint8_t*>(map)[offset_];
+ size_ -= offset_;
+
+ return true;
+}
+
+bool MemoryFileAtOffset::Read(uint64_t addr, void* dst, size_t size) {
+ if (addr + size > size_) {
+ return false;
+ }
+ memcpy(dst, &data_[addr], size);
+ return true;
+}
+
+static bool PtraceRead(pid_t pid, uint64_t addr, long* value) {
+ // ptrace() returns -1 and sets errno when the operation fails.
+ // To disambiguate -1 from a valid result, we clear errno beforehand.
+ errno = 0;
+ *value = ptrace(PTRACE_PEEKTEXT, pid, reinterpret_cast<void*>(addr), nullptr);
+ if (*value == -1 && errno) {
+ return false;
+ }
+ return true;
+}
+
+bool MemoryRemote::Read(uint64_t addr, void* dst, size_t bytes) {
+ size_t bytes_read = 0;
+ long data;
+ size_t align_bytes = addr & (sizeof(long) - 1);
+ if (align_bytes != 0) {
+ if (!PtraceRead(pid_, addr & ~(sizeof(long) - 1), &data)) {
+ return false;
+ }
+ size_t copy_bytes = std::min(sizeof(long) - align_bytes, bytes);
+ memcpy(dst, reinterpret_cast<uint8_t*>(&data) + align_bytes, copy_bytes);
+ addr += copy_bytes;
+ dst = reinterpret_cast<void*>(reinterpret_cast<uintptr_t>(dst) + copy_bytes);
+ bytes -= copy_bytes;
+ bytes_read += copy_bytes;
+ }
+
+ for (size_t i = 0; i < bytes / sizeof(long); i++) {
+ if (!PtraceRead(pid_, addr, &data)) {
+ return false;
+ }
+ memcpy(dst, &data, sizeof(long));
+ dst = reinterpret_cast<void*>(reinterpret_cast<uintptr_t>(dst) + sizeof(long));
+ addr += sizeof(long);
+ bytes_read += sizeof(long);
+ }
+
+ size_t left_over = bytes & (sizeof(long) - 1);
+ if (left_over) {
+ if (!PtraceRead(pid_, addr, &data)) {
+ return false;
+ }
+ memcpy(dst, &data, left_over);
+ bytes_read += left_over;
+ }
+ return true;
+}
+
+bool MemoryLocal::Read(uint64_t addr, void* dst, size_t size) {
+ // The process_vm_readv call does will not always work on remote
+ // processes, so only use it for reads from the current pid.
+ // Use this method to avoid crashes if an address is invalid since
+ // unwind data could try to access any part of the address space.
+ struct iovec local_io;
+ local_io.iov_base = dst;
+ local_io.iov_len = size;
+
+ struct iovec remote_io;
+ remote_io.iov_base = reinterpret_cast<void*>(static_cast<uintptr_t>(addr));
+ remote_io.iov_len = size;
+
+ ssize_t bytes_read = process_vm_readv(getpid(), &local_io, 1, &remote_io, 1, 0);
+ if (bytes_read == -1) {
+ return false;
+ }
+ return static_cast<size_t>(bytes_read) == size;
+}
+
+bool MemoryOffline::Init(const std::string& file, uint64_t offset) {
+ if (!MemoryFileAtOffset::Init(file, offset)) {
+ return false;
+ }
+ // The first uint64_t value is the start of memory.
+ if (!MemoryFileAtOffset::Read(0, &start_, sizeof(start_))) {
+ return false;
+ }
+ // Subtract the first 64 bit value from the total size.
+ size_ -= sizeof(start_);
+ return true;
+}
+
+bool MemoryOffline::Read(uint64_t addr, void* dst, size_t size) {
+ if (addr < start_ || addr + size > start_ + offset_ + size_) {
+ return false;
+ }
+ memcpy(dst, &data_[addr + offset_ - start_ + sizeof(start_)], size);
+ return true;
+}