platform_system_core/libbacktrace/BacktracePtrace.cpp
Christopher Ferris 7937a36c8e Change all uintptr_t to uint64_t in API.
In order to support the offline unwinding properly, get rid of the
usage of non-fixed type uintptr_t from all API calls.

In addition, completely remove the old local and remote unwinding code
that used libunwind.

The next step will be to move the offline unwinding to the new unwinder.

Bug: 65682279

Test: Ran unit tests for libbacktrace/debuggerd.
Test: Ran debuggerd -b on a few arm and arm64 processes.
Test: Ran crasher and crasher64 and verified tombstones look correct.
Change-Id: Ib0c6cee3ad6785a102b74908a3d8e5e93e5c6b33
2018-01-18 17:26:20 -08:00

113 lines
3.1 KiB
C++

/*
* Copyright (C) 2013 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 <stdint.h>
#include <string.h>
#include <sys/param.h>
#include <sys/ptrace.h>
#include <sys/types.h>
#include <ucontext.h>
#include <unistd.h>
#include <backtrace/Backtrace.h>
#include <backtrace/BacktraceMap.h>
#include "BacktraceLog.h"
#include "BacktracePtrace.h"
#include "thread_utils.h"
#if !defined(__APPLE__)
static bool PtraceRead(pid_t tid, uint64_t addr, word_t* out_value) {
// ptrace() returns -1 and sets errno when the operation fails.
// To disambiguate -1 from a valid result, we clear errno beforehand.
errno = 0;
*out_value = ptrace(PTRACE_PEEKTEXT, tid, reinterpret_cast<void*>(addr), nullptr);
if (*out_value == static_cast<word_t>(-1) && errno) {
return false;
}
return true;
}
#endif
bool BacktracePtrace::ReadWord(uint64_t ptr, word_t* out_value) {
#if defined(__APPLE__)
BACK_LOGW("MacOS does not support reading from another pid.");
return false;
#else
if (!VerifyReadWordArgs(ptr, out_value)) {
return false;
}
backtrace_map_t map;
FillInMap(ptr, &map);
if (!BacktraceMap::IsValid(map) || !(map.flags & PROT_READ)) {
return false;
}
return PtraceRead(Tid(), ptr, out_value);
#endif
}
size_t BacktracePtrace::Read(uint64_t addr, uint8_t* buffer, size_t bytes) {
#if defined(__APPLE__)
BACK_LOGW("MacOS does not support reading from another pid.");
return 0;
#else
backtrace_map_t map;
FillInMap(addr, &map);
if (!BacktraceMap::IsValid(map) || !(map.flags & PROT_READ)) {
return 0;
}
bytes = MIN(map.end - addr, bytes);
size_t bytes_read = 0;
word_t data_word;
size_t align_bytes = addr & (sizeof(word_t) - 1);
if (align_bytes != 0) {
if (!PtraceRead(Tid(), addr & ~(sizeof(word_t) - 1), &data_word)) {
return 0;
}
size_t copy_bytes = MIN(sizeof(word_t) - align_bytes, bytes);
memcpy(buffer, reinterpret_cast<uint8_t*>(&data_word) + align_bytes, copy_bytes);
addr += copy_bytes;
buffer += copy_bytes;
bytes -= copy_bytes;
bytes_read += copy_bytes;
}
size_t num_words = bytes / sizeof(word_t);
for (size_t i = 0; i < num_words; i++) {
if (!PtraceRead(Tid(), addr, &data_word)) {
return bytes_read;
}
memcpy(buffer, &data_word, sizeof(word_t));
buffer += sizeof(word_t);
addr += sizeof(word_t);
bytes_read += sizeof(word_t);
}
size_t left_over = bytes & (sizeof(word_t) - 1);
if (left_over) {
if (!PtraceRead(Tid(), addr, &data_word)) {
return bytes_read;
}
memcpy(buffer, &data_word, left_over);
bytes_read += left_over;
}
return bytes_read;
#endif
}