/*
* Copyright (C) 2017 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 <cutils/trace.h>
#include "trace-dev.inc"
#include <cutils/sockets.h>
#include <sys/stat.h>
#include <time.h>
/**
* For tracing in container, tags are written into a socket
* instead of ftrace. Additional data is appended so we need extra space.
*/
#define CONTAINER_ATRACE_MESSAGE_LENGTH (ATRACE_MESSAGE_LENGTH + 512)
static pthread_once_t atrace_once_control = PTHREAD_ONCE_INIT;
// Variables used for tracing in container with socket.
// Note that we need to manually close and reopen socket when Zygote is forking. This requires
// writing and closing sockets on multiple threads. A rwlock is used for avoiding concurrent
// operation on the file descriptor.
static bool atrace_use_container_sock = false;
static int atrace_container_sock_fd = -1;
static pthread_mutex_t atrace_enabling_mutex = PTHREAD_MUTEX_INITIALIZER;
static pthread_rwlock_t atrace_container_sock_rwlock = PTHREAD_RWLOCK_INITIALIZER;
static bool atrace_init_container_sock()
{
pthread_rwlock_wrlock(&atrace_container_sock_rwlock);
atrace_container_sock_fd =
socket_local_client("trace", ANDROID_SOCKET_NAMESPACE_RESERVED, SOCK_SEQPACKET);
if (atrace_container_sock_fd < 0) {
ALOGE("Error opening container trace socket: %s (%d)", strerror(errno), errno);
}
pthread_rwlock_unlock(&atrace_container_sock_rwlock);
return atrace_container_sock_fd != -1;
}
static void atrace_close_container_sock()
{
pthread_rwlock_wrlock(&atrace_container_sock_rwlock);
if (atrace_container_sock_fd != -1) close(atrace_container_sock_fd);
atrace_container_sock_fd = -1;
pthread_rwlock_unlock(&atrace_container_sock_rwlock);
}
// Set whether tracing is enabled in this process. This is used to prevent
// the Zygote process from tracing. We need to close the socket in the container when tracing is
// disabled, and reopen it again after Zygote forking.
void atrace_set_tracing_enabled(bool enabled)
{
pthread_mutex_lock(&atrace_enabling_mutex);
if (atrace_use_container_sock) {
bool already_enabled = atomic_load_explicit(&atrace_is_enabled, memory_order_acquire);
if (enabled && !already_enabled) {
// Trace was disabled previously. Re-initialize container socket.
atrace_init_container_sock();
} else if (!enabled && already_enabled) {
// Trace was enabled previously. Close container socket.
atrace_close_container_sock();
}
}
atomic_store_explicit(&atrace_is_enabled, enabled, memory_order_release);
pthread_mutex_unlock(&atrace_enabling_mutex);
atrace_update_tags();
}
static void atrace_init_once()
{
atrace_marker_fd = open("/sys/kernel/debug/tracing/trace_marker", O_WRONLY | O_CLOEXEC);
if (atrace_marker_fd < 0) {
// We're in container, ftrace may be disabled. In such case, we use the
// socket to write trace event.
// Protect the initialization of container socket from
// atrace_set_tracing_enabled.
pthread_mutex_lock(&atrace_enabling_mutex);
atrace_use_container_sock = true;
bool success = false;
if (atomic_load_explicit(&atrace_is_enabled, memory_order_acquire)) {
success = atrace_init_container_sock();
}
pthread_mutex_unlock(&atrace_enabling_mutex);
if (!success) {
atrace_enabled_tags = 0;
goto done;
}
}
atrace_enabled_tags = atrace_get_property();
done:
atomic_store_explicit(&atrace_is_ready, true, memory_order_release);
}
void atrace_setup()
{
pthread_once(&atrace_once_control, atrace_init_once);
}
static inline uint64_t gettime(clockid_t clk_id)
{
struct timespec ts;
clock_gettime(clk_id, &ts);
return ts.tv_sec * 1000000 + ts.tv_nsec / 1000;
}
// Write trace events to container trace file. Note that we need to amend tid and time information
// here comparing to normal ftrace, where those informations are added by kernel.
#define WRITE_MSG_IN_CONTAINER_LOCKED(ph, sep_before_name, value_format, name, value) { \
char buf[CONTAINER_ATRACE_MESSAGE_LENGTH]; \
int pid = getpid(); \
int tid = gettid(); \
uint64_t ts = gettime(CLOCK_MONOTONIC); \
uint64_t tts = gettime(CLOCK_THREAD_CPUTIME_ID); \
int len = snprintf( \
buf, sizeof(buf), \
ph "|%d|%d|%" PRIu64 "|%" PRIu64 sep_before_name "%s" value_format, \
pid, tid, ts, tts, name, value); \
if (len >= (int) sizeof(buf)) { \
int name_len = strlen(name) - (len - sizeof(buf)) - 1; \
/* Truncate the name to make the message fit. */ \
if (name_len > 0) { \
ALOGW("Truncated name in %s: %s\n", __FUNCTION__, name); \
len = snprintf( \
buf, sizeof(buf), \
ph "|%d|%d|%" PRIu64 "|%" PRIu64 sep_before_name "%.*s" value_format, \
pid, tid, ts, tts, name_len, name, value); \
} else { \
/* Data is still too long. Drop it. */ \
ALOGW("Data is too long in %s: %s\n", __FUNCTION__, name); \
len = 0; \
} \
} \
if (len > 0) { \
write(atrace_container_sock_fd, buf, len); \
} \
}
#define WRITE_MSG_IN_CONTAINER(ph, sep_before_name, value_format, name, value) { \
pthread_rwlock_rdlock(&atrace_container_sock_rwlock); \
if (atrace_container_sock_fd != -1) { \
WRITE_MSG_IN_CONTAINER_LOCKED(ph, sep_before_name, value_format, name, value); \
} \
pthread_rwlock_unlock(&atrace_container_sock_rwlock); \
}
void atrace_begin_body(const char* name)
{
if (CC_LIKELY(atrace_use_container_sock)) {
WRITE_MSG_IN_CONTAINER("B", "|", "%s", name, "");
return;
}
if (atrace_marker_fd < 0) return;
WRITE_MSG("B|%d|", "%s", name, "");
}
void atrace_end_body()
{
if (CC_LIKELY(atrace_use_container_sock)) {
WRITE_MSG_IN_CONTAINER("E", "", "%s", "", "");
return;
}
if (atrace_marker_fd < 0) return;
WRITE_MSG("E|%d", "%s", "", "");
}
void atrace_async_begin_body(const char* name, int32_t cookie)
{
if (CC_LIKELY(atrace_use_container_sock)) {
WRITE_MSG_IN_CONTAINER("S", "|", "|%d", name, cookie);
return;
}
if (atrace_marker_fd < 0) return;
WRITE_MSG("S|%d|", "|%" PRId32, name, cookie);
}
void atrace_async_end_body(const char* name, int32_t cookie)
{
if (CC_LIKELY(atrace_use_container_sock)) {
WRITE_MSG_IN_CONTAINER("F", "|", "|%d", name, cookie);
return;
}
if (atrace_marker_fd < 0) return;
WRITE_MSG("F|%d|", "|%" PRId32, name, cookie);
}
void atrace_int_body(const char* name, int32_t value)
{
if (CC_LIKELY(atrace_use_container_sock)) {
WRITE_MSG_IN_CONTAINER("C", "|", "|%" PRId32, name, value);
return;
}
if (atrace_marker_fd < 0) return;
WRITE_MSG("C|%d|", "|%" PRId32, name, value);
}
void atrace_int64_body(const char* name, int64_t value)
{
if (CC_LIKELY(atrace_use_container_sock)) {
WRITE_MSG_IN_CONTAINER("C", "|", "|%" PRId64, name, value);
return;
}
if (atrace_marker_fd < 0) return;
WRITE_MSG("C|%d|", "|%" PRId64, name, value);
}