451 lines
15 KiB
C++
451 lines
15 KiB
C++
/*
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* Copyright 2008, The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#define LOG_TAG "DEBUG"
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#include "libdebuggerd/utility.h"
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#include <errno.h>
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#include <signal.h>
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#include <string.h>
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#include <sys/capability.h>
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#include <sys/prctl.h>
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#include <sys/ptrace.h>
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#include <sys/uio.h>
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#include <sys/wait.h>
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#include <unistd.h>
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#include <string>
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#include <android-base/logging.h>
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#include <android-base/properties.h>
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#include <android-base/stringprintf.h>
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#include <android-base/strings.h>
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#include <android-base/unique_fd.h>
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#include <bionic/reserved_signals.h>
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#include <debuggerd/handler.h>
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#include <log/log.h>
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#include <unwindstack/Memory.h>
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#include <unwindstack/Unwinder.h>
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using android::base::unique_fd;
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// Whitelist output desired in the logcat output.
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bool is_allowed_in_logcat(enum logtype ltype) {
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if ((ltype == HEADER)
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|| (ltype == REGISTERS)
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|| (ltype == BACKTRACE)) {
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return true;
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}
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return false;
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}
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static bool should_write_to_kmsg() {
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// Write to kmsg if tombstoned isn't up, and we're able to do so.
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if (!android::base::GetBoolProperty("ro.debuggable", false)) {
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return false;
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}
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if (android::base::GetProperty("init.svc.tombstoned", "") == "running") {
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return false;
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}
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return true;
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}
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__attribute__((__weak__, visibility("default")))
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void _LOG(log_t* log, enum logtype ltype, const char* fmt, ...) {
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va_list ap;
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va_start(ap, fmt);
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_VLOG(log, ltype, fmt, ap);
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va_end(ap);
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}
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__attribute__((__weak__, visibility("default")))
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void _VLOG(log_t* log, enum logtype ltype, const char* fmt, va_list ap) {
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bool write_to_tombstone = (log->tfd != -1);
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bool write_to_logcat = is_allowed_in_logcat(ltype)
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&& log->crashed_tid != -1
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&& log->current_tid != -1
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&& (log->crashed_tid == log->current_tid);
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static bool write_to_kmsg = should_write_to_kmsg();
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std::string msg;
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android::base::StringAppendV(&msg, fmt, ap);
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if (msg.empty()) return;
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if (write_to_tombstone) {
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TEMP_FAILURE_RETRY(write(log->tfd, msg.c_str(), msg.size()));
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}
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if (write_to_logcat) {
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__android_log_buf_write(LOG_ID_CRASH, ANDROID_LOG_FATAL, LOG_TAG, msg.c_str());
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if (log->amfd_data != nullptr) {
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*log->amfd_data += msg;
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}
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if (write_to_kmsg) {
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unique_fd kmsg_fd(open("/dev/kmsg_debug", O_WRONLY | O_APPEND | O_CLOEXEC));
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if (kmsg_fd.get() >= 0) {
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// Our output might contain newlines which would otherwise be handled by the android logger.
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// Split the lines up ourselves before sending to the kernel logger.
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if (msg.back() == '\n') {
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msg.back() = '\0';
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}
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std::vector<std::string> fragments = android::base::Split(msg, "\n");
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for (const std::string& fragment : fragments) {
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static constexpr char prefix[] = "<3>DEBUG: ";
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struct iovec iov[3];
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iov[0].iov_base = const_cast<char*>(prefix);
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iov[0].iov_len = strlen(prefix);
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iov[1].iov_base = const_cast<char*>(fragment.c_str());
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iov[1].iov_len = fragment.length();
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iov[2].iov_base = const_cast<char*>("\n");
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iov[2].iov_len = 1;
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TEMP_FAILURE_RETRY(writev(kmsg_fd.get(), iov, 3));
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}
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}
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}
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}
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}
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#define MEMORY_BYTES_TO_DUMP 256
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#define MEMORY_BYTES_PER_LINE 16
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void dump_memory(log_t* log, unwindstack::Memory* memory, uint64_t addr, const std::string& label) {
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// Align the address to sizeof(long) and start 32 bytes before the address.
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addr &= ~(sizeof(long) - 1);
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if (addr >= 4128) {
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addr -= 32;
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}
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// Don't bother if the address looks too low, or looks too high.
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if (addr < 4096 ||
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#if defined(__LP64__)
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addr > 0x4000000000000000UL - MEMORY_BYTES_TO_DUMP) {
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#else
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addr > 0xffff0000 - MEMORY_BYTES_TO_DUMP) {
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#endif
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return;
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}
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_LOG(log, logtype::MEMORY, "\n%s:\n", label.c_str());
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// Dump 256 bytes
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uintptr_t data[MEMORY_BYTES_TO_DUMP/sizeof(uintptr_t)];
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memset(data, 0, MEMORY_BYTES_TO_DUMP);
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size_t bytes = memory->Read(addr, reinterpret_cast<uint8_t*>(data), sizeof(data));
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if (bytes % sizeof(uintptr_t) != 0) {
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// This should never happen, but just in case.
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ALOGE("Bytes read %zu, is not a multiple of %zu", bytes, sizeof(uintptr_t));
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bytes &= ~(sizeof(uintptr_t) - 1);
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}
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uint64_t start = 0;
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bool skip_2nd_read = false;
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if (bytes == 0) {
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// In this case, we might want to try another read at the beginning of
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// the next page only if it's within the amount of memory we would have
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// read.
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size_t page_size = sysconf(_SC_PAGE_SIZE);
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start = ((addr + (page_size - 1)) & ~(page_size - 1)) - addr;
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if (start == 0 || start >= MEMORY_BYTES_TO_DUMP) {
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skip_2nd_read = true;
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}
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}
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if (bytes < MEMORY_BYTES_TO_DUMP && !skip_2nd_read) {
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// Try to do one more read. This could happen if a read crosses a map,
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// but the maps do not have any break between them. Or it could happen
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// if reading from an unreadable map, but the read would cross back
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// into a readable map. Only requires one extra read because a map has
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// to contain at least one page, and the total number of bytes to dump
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// is smaller than a page.
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size_t bytes2 = memory->Read(addr + start + bytes, reinterpret_cast<uint8_t*>(data) + bytes,
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sizeof(data) - bytes - start);
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bytes += bytes2;
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if (bytes2 > 0 && bytes % sizeof(uintptr_t) != 0) {
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// This should never happen, but we'll try and continue any way.
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ALOGE("Bytes after second read %zu, is not a multiple of %zu", bytes, sizeof(uintptr_t));
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bytes &= ~(sizeof(uintptr_t) - 1);
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}
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}
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// Dump the code around memory as:
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// addr contents ascii
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// 0000000000008d34 ef000000e8bd0090 e1b00000512fff1e ............../Q
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// 0000000000008d44 ea00b1f9e92d0090 e3a070fcef000000 ......-..p......
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// On 32-bit machines, there are still 16 bytes per line but addresses and
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// words are of course presented differently.
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uintptr_t* data_ptr = data;
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size_t current = 0;
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size_t total_bytes = start + bytes;
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for (size_t line = 0; line < MEMORY_BYTES_TO_DUMP / MEMORY_BYTES_PER_LINE; line++) {
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std::string logline;
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android::base::StringAppendF(&logline, " %" PRIPTR, addr);
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addr += MEMORY_BYTES_PER_LINE;
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std::string ascii;
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for (size_t i = 0; i < MEMORY_BYTES_PER_LINE / sizeof(uintptr_t); i++) {
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if (current >= start && current + sizeof(uintptr_t) <= total_bytes) {
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android::base::StringAppendF(&logline, " %" PRIPTR, static_cast<uint64_t>(*data_ptr));
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// Fill out the ascii string from the data.
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uint8_t* ptr = reinterpret_cast<uint8_t*>(data_ptr);
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for (size_t val = 0; val < sizeof(uintptr_t); val++, ptr++) {
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if (*ptr >= 0x20 && *ptr < 0x7f) {
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ascii += *ptr;
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} else {
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ascii += '.';
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}
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}
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data_ptr++;
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} else {
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logline += ' ' + std::string(sizeof(uintptr_t) * 2, '-');
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ascii += std::string(sizeof(uintptr_t), '.');
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}
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current += sizeof(uintptr_t);
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}
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_LOG(log, logtype::MEMORY, "%s %s\n", logline.c_str(), ascii.c_str());
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}
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}
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void read_with_default(const char* path, char* buf, size_t len, const char* default_value) {
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unique_fd fd(open(path, O_RDONLY | O_CLOEXEC));
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if (fd != -1) {
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int rc = TEMP_FAILURE_RETRY(read(fd.get(), buf, len - 1));
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if (rc != -1) {
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buf[rc] = '\0';
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// Trim trailing newlines.
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if (rc > 0 && buf[rc - 1] == '\n') {
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buf[rc - 1] = '\0';
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}
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return;
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}
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}
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strcpy(buf, default_value);
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}
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void drop_capabilities() {
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__user_cap_header_struct capheader;
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memset(&capheader, 0, sizeof(capheader));
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capheader.version = _LINUX_CAPABILITY_VERSION_3;
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capheader.pid = 0;
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__user_cap_data_struct capdata[2];
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memset(&capdata, 0, sizeof(capdata));
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if (capset(&capheader, &capdata[0]) == -1) {
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PLOG(FATAL) << "failed to drop capabilities";
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}
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if (prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0) != 0) {
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PLOG(FATAL) << "failed to set PR_SET_NO_NEW_PRIVS";
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}
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}
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bool signal_has_si_addr(const siginfo_t* si) {
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// Manually sent signals won't have si_addr.
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if (si->si_code == SI_USER || si->si_code == SI_QUEUE || si->si_code == SI_TKILL) {
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return false;
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}
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switch (si->si_signo) {
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case SIGBUS:
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case SIGFPE:
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case SIGILL:
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case SIGSEGV:
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case SIGTRAP:
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return true;
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default:
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return false;
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}
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}
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bool signal_has_sender(const siginfo_t* si, pid_t caller_pid) {
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return SI_FROMUSER(si) && (si->si_pid != 0) && (si->si_pid != caller_pid);
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}
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void get_signal_sender(char* buf, size_t n, const siginfo_t* si) {
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snprintf(buf, n, " from pid %d, uid %d", si->si_pid, si->si_uid);
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}
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const char* get_signame(const siginfo_t* si) {
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switch (si->si_signo) {
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case SIGABRT: return "SIGABRT";
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case SIGBUS: return "SIGBUS";
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case SIGFPE: return "SIGFPE";
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case SIGILL: return "SIGILL";
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case SIGSEGV: return "SIGSEGV";
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case SIGSTKFLT: return "SIGSTKFLT";
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case SIGSTOP: return "SIGSTOP";
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case SIGSYS: return "SIGSYS";
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case SIGTRAP: return "SIGTRAP";
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case BIONIC_SIGNAL_DEBUGGER:
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return "<debuggerd signal>";
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default: return "?";
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}
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}
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const char* get_sigcode(const siginfo_t* si) {
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// Try the signal-specific codes...
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switch (si->si_signo) {
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case SIGILL:
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switch (si->si_code) {
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case ILL_ILLOPC: return "ILL_ILLOPC";
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case ILL_ILLOPN: return "ILL_ILLOPN";
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case ILL_ILLADR: return "ILL_ILLADR";
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case ILL_ILLTRP: return "ILL_ILLTRP";
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case ILL_PRVOPC: return "ILL_PRVOPC";
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case ILL_PRVREG: return "ILL_PRVREG";
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case ILL_COPROC: return "ILL_COPROC";
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case ILL_BADSTK: return "ILL_BADSTK";
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case ILL_BADIADDR:
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return "ILL_BADIADDR";
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case __ILL_BREAK:
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return "ILL_BREAK";
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case __ILL_BNDMOD:
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return "ILL_BNDMOD";
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}
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static_assert(NSIGILL == __ILL_BNDMOD, "missing ILL_* si_code");
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break;
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case SIGBUS:
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switch (si->si_code) {
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case BUS_ADRALN: return "BUS_ADRALN";
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case BUS_ADRERR: return "BUS_ADRERR";
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case BUS_OBJERR: return "BUS_OBJERR";
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case BUS_MCEERR_AR: return "BUS_MCEERR_AR";
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case BUS_MCEERR_AO: return "BUS_MCEERR_AO";
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}
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static_assert(NSIGBUS == BUS_MCEERR_AO, "missing BUS_* si_code");
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break;
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case SIGFPE:
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switch (si->si_code) {
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case FPE_INTDIV: return "FPE_INTDIV";
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case FPE_INTOVF: return "FPE_INTOVF";
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case FPE_FLTDIV: return "FPE_FLTDIV";
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case FPE_FLTOVF: return "FPE_FLTOVF";
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case FPE_FLTUND: return "FPE_FLTUND";
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case FPE_FLTRES: return "FPE_FLTRES";
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case FPE_FLTINV: return "FPE_FLTINV";
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case FPE_FLTSUB: return "FPE_FLTSUB";
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case __FPE_DECOVF:
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return "FPE_DECOVF";
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case __FPE_DECDIV:
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return "FPE_DECDIV";
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case __FPE_DECERR:
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return "FPE_DECERR";
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case __FPE_INVASC:
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return "FPE_INVASC";
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case __FPE_INVDEC:
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return "FPE_INVDEC";
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case FPE_FLTUNK:
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return "FPE_FLTUNK";
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case FPE_CONDTRAP:
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return "FPE_CONDTRAP";
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}
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static_assert(NSIGFPE == FPE_CONDTRAP, "missing FPE_* si_code");
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break;
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case SIGSEGV:
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switch (si->si_code) {
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case SEGV_MAPERR: return "SEGV_MAPERR";
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case SEGV_ACCERR: return "SEGV_ACCERR";
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case SEGV_BNDERR: return "SEGV_BNDERR";
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case SEGV_PKUERR: return "SEGV_PKUERR";
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case SEGV_ACCADI:
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return "SEGV_ACCADI";
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case SEGV_ADIDERR:
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return "SEGV_ADIDERR";
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case SEGV_ADIPERR:
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return "SEGV_ADIPERR";
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}
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static_assert(NSIGSEGV == SEGV_ADIPERR, "missing SEGV_* si_code");
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break;
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case SIGSYS:
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switch (si->si_code) {
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case SYS_SECCOMP: return "SYS_SECCOMP";
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}
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static_assert(NSIGSYS == SYS_SECCOMP, "missing SYS_* si_code");
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break;
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case SIGTRAP:
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switch (si->si_code) {
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case TRAP_BRKPT: return "TRAP_BRKPT";
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case TRAP_TRACE: return "TRAP_TRACE";
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case TRAP_BRANCH: return "TRAP_BRANCH";
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case TRAP_HWBKPT: return "TRAP_HWBKPT";
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case TRAP_UNK:
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return "TRAP_UNDIAGNOSED";
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}
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if ((si->si_code & 0xff) == SIGTRAP) {
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switch ((si->si_code >> 8) & 0xff) {
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case PTRACE_EVENT_FORK:
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return "PTRACE_EVENT_FORK";
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case PTRACE_EVENT_VFORK:
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return "PTRACE_EVENT_VFORK";
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case PTRACE_EVENT_CLONE:
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return "PTRACE_EVENT_CLONE";
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case PTRACE_EVENT_EXEC:
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return "PTRACE_EVENT_EXEC";
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case PTRACE_EVENT_VFORK_DONE:
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return "PTRACE_EVENT_VFORK_DONE";
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case PTRACE_EVENT_EXIT:
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return "PTRACE_EVENT_EXIT";
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case PTRACE_EVENT_SECCOMP:
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return "PTRACE_EVENT_SECCOMP";
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case PTRACE_EVENT_STOP:
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return "PTRACE_EVENT_STOP";
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}
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}
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static_assert(NSIGTRAP == TRAP_UNK, "missing TRAP_* si_code");
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break;
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}
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// Then the other codes...
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switch (si->si_code) {
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case SI_USER: return "SI_USER";
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case SI_KERNEL: return "SI_KERNEL";
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case SI_QUEUE: return "SI_QUEUE";
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case SI_TIMER: return "SI_TIMER";
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case SI_MESGQ: return "SI_MESGQ";
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case SI_ASYNCIO: return "SI_ASYNCIO";
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case SI_SIGIO: return "SI_SIGIO";
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case SI_TKILL: return "SI_TKILL";
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case SI_DETHREAD: return "SI_DETHREAD";
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}
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// Then give up...
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return "?";
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}
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void log_backtrace(log_t* log, unwindstack::Unwinder* unwinder, const char* prefix) {
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if (unwinder->elf_from_memory_not_file()) {
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_LOG(log, logtype::BACKTRACE,
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"%sNOTE: Function names and BuildId information is missing for some frames due\n", prefix);
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_LOG(log, logtype::BACKTRACE,
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"%sNOTE: to unreadable libraries. For unwinds of apps, only shared libraries\n", prefix);
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_LOG(log, logtype::BACKTRACE, "%sNOTE: found under the lib/ directory are readable.\n", prefix);
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#if defined(ROOT_POSSIBLE)
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_LOG(log, logtype::BACKTRACE,
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"%sNOTE: On this device, run setenforce 0 to make the libraries readable.\n", prefix);
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#endif
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}
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unwinder->SetDisplayBuildID(true);
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for (size_t i = 0; i < unwinder->NumFrames(); i++) {
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_LOG(log, logtype::BACKTRACE, "%s%s\n", prefix, unwinder->FormatFrame(i).c_str());
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}
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}
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