platform_system_core/debuggerd/utility.cpp

186 lines
5.6 KiB
C++

/*
* Copyright 2008, 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 "utility.h"
#include <errno.h>
#include <signal.h>
#include <string.h>
#include <unistd.h>
#include <sys/ptrace.h>
#include <sys/wait.h>
#include <backtrace/Backtrace.h>
#include <base/file.h>
#include <log/log.h>
const int SLEEP_TIME_USEC = 50000; // 0.05 seconds
const int MAX_TOTAL_SLEEP_USEC = 10000000; // 10 seconds
// Whitelist output desired in the logcat output.
bool is_allowed_in_logcat(enum logtype ltype) {
if ((ltype == ERROR)
|| (ltype == HEADER)
|| (ltype == REGISTERS)
|| (ltype == BACKTRACE)) {
return true;
}
return false;
}
void _LOG(log_t* log, enum logtype ltype, const char* fmt, ...) {
bool write_to_tombstone = (log->tfd != -1);
bool write_to_logcat = is_allowed_in_logcat(ltype)
&& log->crashed_tid != -1
&& log->current_tid != -1
&& (log->crashed_tid == log->current_tid);
bool write_to_activitymanager = (log->amfd != -1);
char buf[512];
va_list ap;
va_start(ap, fmt);
vsnprintf(buf, sizeof(buf), fmt, ap);
va_end(ap);
size_t len = strlen(buf);
if (len <= 0) {
return;
}
if (write_to_tombstone) {
TEMP_FAILURE_RETRY(write(log->tfd, buf, len));
}
if (write_to_logcat) {
__android_log_buf_write(LOG_ID_CRASH, ANDROID_LOG_FATAL, LOG_TAG, buf);
if (write_to_activitymanager) {
if (!android::base::WriteFully(log->amfd, buf, len)) {
// timeout or other failure on write; stop informing the activity manager
ALOGE("AM write failed: %s", strerror(errno));
log->amfd = -1;
}
}
}
}
int wait_for_sigstop(pid_t tid, int* total_sleep_time_usec, bool* detach_failed) {
bool allow_dead_tid = false;
for (;;) {
int status;
pid_t n = TEMP_FAILURE_RETRY(waitpid(tid, &status, __WALL | WNOHANG));
if (n == -1) {
ALOGE("waitpid failed: tid %d, %s", tid, strerror(errno));
break;
} else if (n == tid) {
if (WIFSTOPPED(status)) {
return WSTOPSIG(status);
} else {
ALOGE("unexpected waitpid response: n=%d, status=%08x\n", n, status);
// This is the only circumstance under which we can allow a detach
// to fail with ESRCH, which indicates the tid has exited.
allow_dead_tid = true;
break;
}
}
if (*total_sleep_time_usec > MAX_TOTAL_SLEEP_USEC) {
ALOGE("timed out waiting for stop signal: tid=%d", tid);
break;
}
usleep(SLEEP_TIME_USEC);
*total_sleep_time_usec += SLEEP_TIME_USEC;
}
if (ptrace(PTRACE_DETACH, tid, 0, 0) != 0) {
if (allow_dead_tid && errno == ESRCH) {
ALOGE("tid exited before attach completed: tid %d", tid);
} else {
*detach_failed = true;
ALOGE("detach failed: tid %d, %s", tid, strerror(errno));
}
}
return -1;
}
void dump_memory(log_t* log, pid_t tid, uintptr_t addr) {
char code_buffer[64];
char ascii_buffer[32];
uintptr_t p, end;
p = addr & ~(sizeof(long) - 1);
/* Dump 32 bytes before addr */
p -= 32;
if (p > addr) {
/* catch underflow */
p = 0;
}
/* Dump 256 bytes */
end = p + 256;
/* catch overflow; 'end - p' has to be multiples of 16 */
while (end < p) {
end -= 16;
}
/* Dump the code around PC as:
* addr contents ascii
* 0000000000008d34 ef000000e8bd0090 e1b00000512fff1e ............../Q
* 0000000000008d44 ea00b1f9e92d0090 e3a070fcef000000 ......-..p......
* On 32-bit machines, there are still 16 bytes per line but addresses and
* words are of course presented differently.
*/
while (p < end) {
char* asc_out = ascii_buffer;
int len = snprintf(code_buffer, sizeof(code_buffer), "%" PRIPTR " ", p);
for (size_t i = 0; i < 16/sizeof(long); i++) {
long data = ptrace(PTRACE_PEEKTEXT, tid, (void*)p, NULL);
if (data == -1 && errno != 0) {
// ptrace failed, probably because we're dumping memory in an
// unmapped or inaccessible page.
#ifdef __LP64__
len += sprintf(code_buffer + len, "---------------- ");
#else
len += sprintf(code_buffer + len, "-------- ");
#endif
} else {
len += sprintf(code_buffer + len, "%" PRIPTR " ",
static_cast<uintptr_t>(data));
}
for (size_t j = 0; j < sizeof(long); j++) {
/*
* Our isprint() allows high-ASCII characters that display
* differently (often badly) in different viewers, so we
* just use a simpler test.
*/
char val = (data >> (j*8)) & 0xff;
if (val >= 0x20 && val < 0x7f) {
*asc_out++ = val;
} else {
*asc_out++ = '.';
}
}
p += sizeof(long);
}
*asc_out = '\0';
_LOG(log, logtype::MEMORY, " %s %s\n", code_buffer, ascii_buffer);
}
}