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platform_system_core/debuggerd/tombstone.cpp
Christopher Ferris dac26a76c3 Merge "Fix null pointer dereference." into nyc-dev
2016-05-05 21:19:52 +00:00

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/*
* Copyright (C) 2012-2014 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 "DEBUG"
#include <dirent.h>
#include <errno.h>
#include <fcntl.h>
#include <inttypes.h>
#include <signal.h>
#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <sys/ptrace.h>
#include <sys/stat.h>
#include <memory>
#include <string>
#include <private/android_filesystem_config.h>
#include <android-base/stringprintf.h>
#include <cutils/properties.h>
#include <log/log.h>
#include <log/logger.h>
#include <log/logprint.h>
#include <backtrace/Backtrace.h>
#include <backtrace/BacktraceMap.h>
#include <selinux/android.h>
#include "backtrace.h"
#include "elf_utils.h"
#include "machine.h"
#include "tombstone.h"
#define STACK_WORDS 16
#define MAX_TOMBSTONES 10
#define TOMBSTONE_DIR "/data/tombstones"
#define TOMBSTONE_TEMPLATE (TOMBSTONE_DIR"/tombstone_%02d")
static bool signal_has_si_addr(int sig) {
switch (sig) {
case SIGBUS:
case SIGFPE:
case SIGILL:
case SIGSEGV:
case SIGTRAP:
return true;
default:
return false;
}
}
static const char* get_signame(int sig) {
switch(sig) {
case SIGABRT: return "SIGABRT";
case SIGBUS: return "SIGBUS";
case SIGFPE: return "SIGFPE";
case SIGILL: return "SIGILL";
case SIGSEGV: return "SIGSEGV";
#if defined(SIGSTKFLT)
case SIGSTKFLT: return "SIGSTKFLT";
#endif
case SIGSTOP: return "SIGSTOP";
case SIGTRAP: return "SIGTRAP";
default: return "?";
}
}
static const char* get_sigcode(int signo, int code) {
// Try the signal-specific codes...
switch (signo) {
case SIGILL:
switch (code) {
case ILL_ILLOPC: return "ILL_ILLOPC";
case ILL_ILLOPN: return "ILL_ILLOPN";
case ILL_ILLADR: return "ILL_ILLADR";
case ILL_ILLTRP: return "ILL_ILLTRP";
case ILL_PRVOPC: return "ILL_PRVOPC";
case ILL_PRVREG: return "ILL_PRVREG";
case ILL_COPROC: return "ILL_COPROC";
case ILL_BADSTK: return "ILL_BADSTK";
}
static_assert(NSIGILL == ILL_BADSTK, "missing ILL_* si_code");
break;
case SIGBUS:
switch (code) {
case BUS_ADRALN: return "BUS_ADRALN";
case BUS_ADRERR: return "BUS_ADRERR";
case BUS_OBJERR: return "BUS_OBJERR";
case BUS_MCEERR_AR: return "BUS_MCEERR_AR";
case BUS_MCEERR_AO: return "BUS_MCEERR_AO";
}
static_assert(NSIGBUS == BUS_MCEERR_AO, "missing BUS_* si_code");
break;
case SIGFPE:
switch (code) {
case FPE_INTDIV: return "FPE_INTDIV";
case FPE_INTOVF: return "FPE_INTOVF";
case FPE_FLTDIV: return "FPE_FLTDIV";
case FPE_FLTOVF: return "FPE_FLTOVF";
case FPE_FLTUND: return "FPE_FLTUND";
case FPE_FLTRES: return "FPE_FLTRES";
case FPE_FLTINV: return "FPE_FLTINV";
case FPE_FLTSUB: return "FPE_FLTSUB";
}
static_assert(NSIGFPE == FPE_FLTSUB, "missing FPE_* si_code");
break;
case SIGSEGV:
switch (code) {
case SEGV_MAPERR: return "SEGV_MAPERR";
case SEGV_ACCERR: return "SEGV_ACCERR";
#if defined(SEGV_BNDERR)
case SEGV_BNDERR: return "SEGV_BNDERR";
#endif
}
#if defined(SEGV_BNDERR)
static_assert(NSIGSEGV == SEGV_BNDERR, "missing SEGV_* si_code");
#else
static_assert(NSIGSEGV == SEGV_ACCERR, "missing SEGV_* si_code");
#endif
break;
case SIGTRAP:
switch (code) {
case TRAP_BRKPT: return "TRAP_BRKPT";
case TRAP_TRACE: return "TRAP_TRACE";
case TRAP_BRANCH: return "TRAP_BRANCH";
case TRAP_HWBKPT: return "TRAP_HWBKPT";
}
static_assert(NSIGTRAP == TRAP_HWBKPT, "missing TRAP_* si_code");
break;
}
// Then the other codes...
switch (code) {
case SI_USER: return "SI_USER";
case SI_KERNEL: return "SI_KERNEL";
case SI_QUEUE: return "SI_QUEUE";
case SI_TIMER: return "SI_TIMER";
case SI_MESGQ: return "SI_MESGQ";
case SI_ASYNCIO: return "SI_ASYNCIO";
case SI_SIGIO: return "SI_SIGIO";
case SI_TKILL: return "SI_TKILL";
case SI_DETHREAD: return "SI_DETHREAD";
}
// Then give up...
return "?";
}
static void dump_header_info(log_t* log) {
char fingerprint[PROPERTY_VALUE_MAX];
char revision[PROPERTY_VALUE_MAX];
property_get("ro.build.fingerprint", fingerprint, "unknown");
property_get("ro.revision", revision, "unknown");
_LOG(log, logtype::HEADER, "Build fingerprint: '%s'\n", fingerprint);
_LOG(log, logtype::HEADER, "Revision: '%s'\n", revision);
_LOG(log, logtype::HEADER, "ABI: '%s'\n", ABI_STRING);
}
static void dump_signal_info(log_t* log, pid_t tid, int signal, int si_code) {
siginfo_t si;
memset(&si, 0, sizeof(si));
if (ptrace(PTRACE_GETSIGINFO, tid, 0, &si) == -1) {
ALOGE("cannot get siginfo: %s\n", strerror(errno));
return;
}
// bionic has to re-raise some signals, which overwrites the si_code with SI_TKILL.
si.si_code = si_code;
char addr_desc[32]; // ", fault addr 0x1234"
if (signal_has_si_addr(signal)) {
snprintf(addr_desc, sizeof(addr_desc), "%p", si.si_addr);
} else {
snprintf(addr_desc, sizeof(addr_desc), "--------");
}
_LOG(log, logtype::HEADER, "signal %d (%s), code %d (%s), fault addr %s\n",
signal, get_signame(signal), si.si_code, get_sigcode(signal, si.si_code), addr_desc);
}
static void dump_thread_info(log_t* log, pid_t pid, pid_t tid) {
char path[64];
char threadnamebuf[1024];
char* threadname = nullptr;
FILE *fp;
snprintf(path, sizeof(path), "/proc/%d/comm", tid);
if ((fp = fopen(path, "r"))) {
threadname = fgets(threadnamebuf, sizeof(threadnamebuf), fp);
fclose(fp);
if (threadname) {
size_t len = strlen(threadname);
if (len && threadname[len - 1] == '\n') {
threadname[len - 1] = '\0';
}
}
}
// Blacklist logd, logd.reader, logd.writer, logd.auditd, logd.control ...
static const char logd[] = "logd";
if (threadname != nullptr && !strncmp(threadname, logd, sizeof(logd) - 1)
&& (!threadname[sizeof(logd) - 1] || (threadname[sizeof(logd) - 1] == '.'))) {
log->should_retrieve_logcat = false;
}
char procnamebuf[1024];
char* procname = nullptr;
snprintf(path, sizeof(path), "/proc/%d/cmdline", pid);
if ((fp = fopen(path, "r"))) {
procname = fgets(procnamebuf, sizeof(procnamebuf), fp);
fclose(fp);
}
_LOG(log, logtype::HEADER, "pid: %d, tid: %d, name: %s >>> %s <<<\n", pid, tid,
threadname ? threadname : "UNKNOWN", procname ? procname : "UNKNOWN");
}
static void dump_stack_segment(
Backtrace* backtrace, log_t* log, uintptr_t* sp, size_t words, int label) {
// Read the data all at once.
word_t stack_data[words];
size_t bytes_read = backtrace->Read(*sp, reinterpret_cast<uint8_t*>(&stack_data[0]), sizeof(word_t) * words);
words = bytes_read / sizeof(word_t);
std::string line;
for (size_t i = 0; i < words; i++) {
line = " ";
if (i == 0 && label >= 0) {
// Print the label once.
line += android::base::StringPrintf("#%02d ", label);
} else {
line += " ";
}
line += android::base::StringPrintf("%" PRIPTR " %" PRIPTR, *sp, stack_data[i]);
backtrace_map_t map;
backtrace->FillInMap(stack_data[i], &map);
if (BacktraceMap::IsValid(map) && !map.name.empty()) {
line += " " + map.name;
uintptr_t offset = 0;
std::string func_name(backtrace->GetFunctionName(stack_data[i], &offset));
if (!func_name.empty()) {
line += " (" + func_name;
if (offset) {
line += android::base::StringPrintf("+%" PRIuPTR, offset);
}
line += ')';
}
}
_LOG(log, logtype::STACK, "%s\n", line.c_str());
*sp += sizeof(word_t);
}
}
static void dump_stack(Backtrace* backtrace, log_t* log) {
size_t first = 0, last;
for (size_t i = 0; i < backtrace->NumFrames(); i++) {
const backtrace_frame_data_t* frame = backtrace->GetFrame(i);
if (frame->sp) {
if (!first) {
first = i+1;
}
last = i;
}
}
if (!first) {
return;
}
first--;
// Dump a few words before the first frame.
word_t sp = backtrace->GetFrame(first)->sp - STACK_WORDS * sizeof(word_t);
dump_stack_segment(backtrace, log, &sp, STACK_WORDS, -1);
// Dump a few words from all successive frames.
// Only log the first 3 frames, put the rest in the tombstone.
for (size_t i = first; i <= last; i++) {
const backtrace_frame_data_t* frame = backtrace->GetFrame(i);
if (sp != frame->sp) {
_LOG(log, logtype::STACK, " ........ ........\n");
sp = frame->sp;
}
if (i == last) {
dump_stack_segment(backtrace, log, &sp, STACK_WORDS, i);
if (sp < frame->sp + frame->stack_size) {
_LOG(log, logtype::STACK, " ........ ........\n");
}
} else {
size_t words = frame->stack_size / sizeof(word_t);
if (words == 0) {
words = 1;
} else if (words > STACK_WORDS) {
words = STACK_WORDS;
}
dump_stack_segment(backtrace, log, &sp, words, i);
}
}
}
static std::string get_addr_string(uintptr_t addr) {
std::string addr_str;
#if defined(__LP64__)
addr_str = android::base::StringPrintf("%08x'%08x",
static_cast<uint32_t>(addr >> 32),
static_cast<uint32_t>(addr & 0xffffffff));
#else
addr_str = android::base::StringPrintf("%08x", addr);
#endif
return addr_str;
}
static void dump_abort_message(Backtrace* backtrace, log_t* log, uintptr_t address) {
if (address == 0) {
return;
}
address += sizeof(size_t); // Skip the buffer length.
char msg[512];
memset(msg, 0, sizeof(msg));
char* p = &msg[0];
while (p < &msg[sizeof(msg)]) {
word_t data;
size_t len = sizeof(word_t);
if (!backtrace->ReadWord(address, &data)) {
break;
}
address += sizeof(word_t);
while (len > 0 && (*p++ = (data >> (sizeof(word_t) - len) * 8) & 0xff) != 0) {
len--;
}
}
msg[sizeof(msg) - 1] = '\0';
_LOG(log, logtype::HEADER, "Abort message: '%s'\n", msg);
}
static void dump_all_maps(Backtrace* backtrace, BacktraceMap* map, log_t* log, pid_t tid) {
bool print_fault_address_marker = false;
uintptr_t addr = 0;
siginfo_t si;
memset(&si, 0, sizeof(si));
if (ptrace(PTRACE_GETSIGINFO, tid, 0, &si) != -1) {
print_fault_address_marker = signal_has_si_addr(si.si_signo);
addr = reinterpret_cast<uintptr_t>(si.si_addr);
} else {
ALOGE("Cannot get siginfo for %d: %s\n", tid, strerror(errno));
}
_LOG(log, logtype::MAPS, "\n");
if (!print_fault_address_marker) {
_LOG(log, logtype::MAPS, "memory map:\n");
} else {
_LOG(log, logtype::MAPS, "memory map: (fault address prefixed with --->)\n");
if (map->begin() != map->end() && addr < map->begin()->start) {
_LOG(log, logtype::MAPS, "--->Fault address falls at %s before any mapped regions\n",
get_addr_string(addr).c_str());
print_fault_address_marker = false;
}
}
std::string line;
for (BacktraceMap::const_iterator it = map->begin(); it != map->end(); ++it) {
line = " ";
if (print_fault_address_marker) {
if (addr < it->start) {
_LOG(log, logtype::MAPS, "--->Fault address falls at %s between mapped regions\n",
get_addr_string(addr).c_str());
print_fault_address_marker = false;
} else if (addr >= it->start && addr < it->end) {
line = "--->";
print_fault_address_marker = false;
}
}
line += get_addr_string(it->start) + '-' + get_addr_string(it->end - 1) + ' ';
if (it->flags & PROT_READ) {
line += 'r';
} else {
line += '-';
}
if (it->flags & PROT_WRITE) {
line += 'w';
} else {
line += '-';
}
if (it->flags & PROT_EXEC) {
line += 'x';
} else {
line += '-';
}
line += android::base::StringPrintf(" %8" PRIxPTR " %8" PRIxPTR,
it->offset, it->end - it->start);
bool space_needed = true;
if (it->name.length() > 0) {
space_needed = false;
line += " " + it->name;
std::string build_id;
if ((it->flags & PROT_READ) && elf_get_build_id(backtrace, it->start, &build_id)) {
line += " (BuildId: " + build_id + ")";
}
}
if (it->load_base != 0) {
if (space_needed) {
line += ' ';
}
line += android::base::StringPrintf(" (load base 0x%" PRIxPTR ")", it->load_base);
}
_LOG(log, logtype::MAPS, "%s\n", line.c_str());
}
if (print_fault_address_marker) {
_LOG(log, logtype::MAPS, "--->Fault address falls at %s after any mapped regions\n",
get_addr_string(addr).c_str());
}
}
static void dump_backtrace_and_stack(Backtrace* backtrace, log_t* log) {
if (backtrace->NumFrames()) {
_LOG(log, logtype::BACKTRACE, "\nbacktrace:\n");
dump_backtrace_to_log(backtrace, log, " ");
_LOG(log, logtype::STACK, "\nstack:\n");
dump_stack(backtrace, log);
}
}
static void dump_thread(log_t* log, pid_t pid, pid_t tid, BacktraceMap* map, int signal,
int si_code, uintptr_t abort_msg_address, bool primary_thread) {
log->current_tid = tid;
if (!primary_thread) {
_LOG(log, logtype::THREAD, "--- --- --- --- --- --- --- --- --- --- --- --- --- --- --- ---\n");
}
dump_thread_info(log, pid, tid);
if (signal) {
dump_signal_info(log, tid, signal, si_code);
}
std::unique_ptr<Backtrace> backtrace(Backtrace::Create(pid, tid, map));
if (primary_thread) {
dump_abort_message(backtrace.get(), log, abort_msg_address);
}
dump_registers(log, tid);
if (backtrace->Unwind(0)) {
dump_backtrace_and_stack(backtrace.get(), log);
} else {
ALOGE("Unwind failed: pid = %d, tid = %d", pid, tid);
}
if (primary_thread) {
dump_memory_and_code(log, backtrace.get());
if (map) {
dump_all_maps(backtrace.get(), map, log, tid);
}
}
log->current_tid = log->crashed_tid;
}
// Reads the contents of the specified log device, filters out the entries
// that don't match the specified pid, and writes them to the tombstone file.
//
// If "tail" is non-zero, log the last "tail" number of lines.
static EventTagMap* g_eventTagMap = NULL;
static void dump_log_file(
log_t* log, pid_t pid, const char* filename, unsigned int tail) {
bool first = true;
struct logger_list* logger_list;
if (!log->should_retrieve_logcat) {
return;
}
logger_list = android_logger_list_open(
android_name_to_log_id(filename), ANDROID_LOG_RDONLY | ANDROID_LOG_NONBLOCK, tail, pid);
if (!logger_list) {
ALOGE("Unable to open %s: %s\n", filename, strerror(errno));
return;
}
struct log_msg log_entry;
while (true) {
ssize_t actual = android_logger_list_read(logger_list, &log_entry);
struct logger_entry* entry;
if (actual < 0) {
if (actual == -EINTR) {
// interrupted by signal, retry
continue;
} else if (actual == -EAGAIN) {
// non-blocking EOF; we're done
break;
} else {
ALOGE("Error while reading log: %s\n", strerror(-actual));
break;
}
} else if (actual == 0) {
ALOGE("Got zero bytes while reading log: %s\n", strerror(errno));
break;
}
// NOTE: if you ALOGV something here, this will spin forever,
// because you will be writing as fast as you're reading. Any
// high-frequency debug diagnostics should just be written to
// the tombstone file.
entry = &log_entry.entry_v1;
if (first) {
_LOG(log, logtype::LOGS, "--------- %slog %s\n",
tail ? "tail end of " : "", filename);
first = false;
}
// Msg format is: <priority:1><tag:N>\0<message:N>\0
//
// We want to display it in the same format as "logcat -v threadtime"
// (although in this case the pid is redundant).
static const char* kPrioChars = "!.VDIWEFS";
unsigned hdr_size = log_entry.entry.hdr_size;
if (!hdr_size) {
hdr_size = sizeof(log_entry.entry_v1);
}
char* msg = reinterpret_cast<char*>(log_entry.buf) + hdr_size;
char timeBuf[32];
time_t sec = static_cast<time_t>(entry->sec);
struct tm tmBuf;
struct tm* ptm;
ptm = localtime_r(&sec, &tmBuf);
strftime(timeBuf, sizeof(timeBuf), "%m-%d %H:%M:%S", ptm);
if (log_entry.id() == LOG_ID_EVENTS) {
if (!g_eventTagMap) {
g_eventTagMap = android_openEventTagMap(EVENT_TAG_MAP_FILE);
}
AndroidLogEntry e;
char buf[512];
android_log_processBinaryLogBuffer(entry, &e, g_eventTagMap, buf, sizeof(buf));
_LOG(log, logtype::LOGS, "%s.%03d %5d %5d %c %-8s: %s\n",
timeBuf, entry->nsec / 1000000, entry->pid, entry->tid,
'I', e.tag, e.message);
continue;
}
unsigned char prio = msg[0];
char* tag = msg + 1;
msg = tag + strlen(tag) + 1;
// consume any trailing newlines
char* nl = msg + strlen(msg) - 1;
while (nl >= msg && *nl == '\n') {
*nl-- = '\0';
}
char prioChar = (prio < strlen(kPrioChars) ? kPrioChars[prio] : '?');
// Look for line breaks ('\n') and display each text line
// on a separate line, prefixed with the header, like logcat does.
do {
nl = strchr(msg, '\n');
if (nl) {
*nl = '\0';
++nl;
}
_LOG(log, logtype::LOGS, "%s.%03d %5d %5d %c %-8s: %s\n",
timeBuf, entry->nsec / 1000000, entry->pid, entry->tid,
prioChar, tag, msg);
} while ((msg = nl));
}
android_logger_list_free(logger_list);
}
// Dumps the logs generated by the specified pid to the tombstone, from both
// "system" and "main" log devices. Ideally we'd interleave the output.
static void dump_logs(log_t* log, pid_t pid, unsigned int tail) {
dump_log_file(log, pid, "system", tail);
dump_log_file(log, pid, "main", tail);
}
// Dumps all information about the specified pid to the tombstone.
static void dump_crash(log_t* log, BacktraceMap* map, pid_t pid, pid_t tid,
const std::set<pid_t>& siblings, int signal, int si_code,
uintptr_t abort_msg_address) {
// don't copy log messages to tombstone unless this is a dev device
char value[PROPERTY_VALUE_MAX];
property_get("ro.debuggable", value, "0");
bool want_logs = (value[0] == '1');
_LOG(log, logtype::HEADER,
"*** *** *** *** *** *** *** *** *** *** *** *** *** *** *** ***\n");
dump_header_info(log);
dump_thread(log, pid, tid, map, signal, si_code, abort_msg_address, true);
if (want_logs) {
dump_logs(log, pid, 5);
}
if (!siblings.empty()) {
for (pid_t sibling : siblings) {
dump_thread(log, pid, sibling, map, 0, 0, 0, false);
}
}
if (want_logs) {
dump_logs(log, pid, 0);
}
}
// open_tombstone - find an available tombstone slot, if any, of the
// form tombstone_XX where XX is 00 to MAX_TOMBSTONES-1, inclusive. If no
// file is available, we reuse the least-recently-modified file.
int open_tombstone(std::string* out_path) {
// In a single pass, find an available slot and, in case none
// exist, find and record the least-recently-modified file.
char path[128];
int fd = -1;
int oldest = -1;
struct stat oldest_sb;
for (int i = 0; i < MAX_TOMBSTONES; i++) {
snprintf(path, sizeof(path), TOMBSTONE_TEMPLATE, i);
struct stat sb;
if (stat(path, &sb) == 0) {
if (oldest < 0 || sb.st_mtime < oldest_sb.st_mtime) {
oldest = i;
oldest_sb.st_mtime = sb.st_mtime;
}
continue;
}
if (errno != ENOENT) continue;
fd = open(path, O_CREAT | O_EXCL | O_WRONLY | O_NOFOLLOW | O_CLOEXEC, 0600);
if (fd < 0) continue; // raced ?
if (out_path) {
*out_path = path;
}
fchown(fd, AID_SYSTEM, AID_SYSTEM);
return fd;
}
if (oldest < 0) {
ALOGE("debuggerd: failed to find a valid tombstone, default to using tombstone 0.\n");
oldest = 0;
}
// we didn't find an available file, so we clobber the oldest one
snprintf(path, sizeof(path), TOMBSTONE_TEMPLATE, oldest);
fd = open(path, O_CREAT | O_TRUNC | O_WRONLY | O_NOFOLLOW | O_CLOEXEC, 0600);
if (fd < 0) {
ALOGE("debuggerd: failed to open tombstone file '%s': %s\n", path, strerror(errno));
return -1;
}
if (out_path) {
*out_path = path;
}
fchown(fd, AID_SYSTEM, AID_SYSTEM);
return fd;
}
void engrave_tombstone(int tombstone_fd, BacktraceMap* map, pid_t pid, pid_t tid,
const std::set<pid_t>& siblings, int signal, int original_si_code,
uintptr_t abort_msg_address, std::string* amfd_data) {
log_t log;
log.current_tid = tid;
log.crashed_tid = tid;
if (tombstone_fd < 0) {
ALOGE("debuggerd: skipping tombstone write, nothing to do.\n");
return;
}
log.tfd = tombstone_fd;
log.amfd_data = amfd_data;
dump_crash(&log, map, pid, tid, siblings, signal, original_si_code, abort_msg_address);
}
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