log分析
log分析用于定位一些无法断点调试的一些疑难杂症。所以需要熟悉bugreport到底有哪些内容，哪些模块都打印log。读完下文你会有不一样的认识。基于Android O源码
命令：
adb bugreport > bugreport.txt
源码：
#include instead\n" );
fprintf(stderr, "=============================================================================\n\n\n");
// 启动dumpstate服务
property_set("ctl.start", "dumpstate");
//需要多次尝试，直到dumpstate服务启动完成，才能建立socket通信
int s;
for (int i = 0; i < 20; i++) {
//创建socket client
s = socket_local_client("dumpstate", ANDROID_SOCKET_NAMESPACE_RESERVED, SOCK_STREAM);
if (s >= 0)
break;
// 休眠1s后再次尝试连接
sleep(1);
}
if (s == -1) {
printf("Failed to connect to dumpstate service: %s\n", strerror(errno));
return 1;
}
//当3分钟没有任何数据可读，则超时停止读取并退出。
//dumpstate服务中不存在大于1分钟的timetout，因而不可预见的超时的情况下留有很大的回旋余地。
struct timeval tv;
tv.tv_sec = 3 * 60;
tv.tv_usec = 0;
if (setsockopt(s, SOL_SOCKET, SO_RCVTIMEO, &tv, sizeof(tv)) == -1) {
printf("WARNING: Cannot set socket timeout: %s\n", strerror(errno));
}
while (1) {
char buffer[65536];
ssize_t bytes_read = TEMP_FAILURE_RETRY(read(s, buffer, sizeof(buffer)));
if (bytes_read == 0) {
break;
} else if (bytes_read == -1) {
// EAGAIN意味着timeout，Bugreport读异常终止
if (errno == EAGAIN) {
errno = ETIMEDOUT;
}
printf("\nBugreport read terminated abnormally (%s).\n", strerror(errno));
break;
}
ssize_t bytes_to_send = bytes_read;
ssize_t bytes_written;
do {
//循环读取信息
bytes_written = TEMP_FAILURE_RETRY(write(STDOUT_FILENO,
buffer + bytes_read - bytes_to_send,
bytes_to_send));
if (bytes_written == -1) {
printf("Failed to write data to stdout: read %zd, trying to send %zd (%s)\n",
bytes_read, bytes_to_send, strerror(errno));
return 1;//将数据无法写入stdout
}
bytes_to_send -= bytes_written;
} while (bytes_written != 0 && bytes_to_send > 0);
}
close(s);
return 0;
}
至于这里property_set(“ctl.start”, “dumpstate”)为什么会写着启动服务，查阅资料说是触发init进程fork进程/system/bin/dumpstate
dumpstate.cpp
int main(int argc, char *argv[]) {
//设置优先级，防止被lmk，可以说很牛逼了，直接给文件中写oom_adj的值，root权限就是吊，直接不死进程
/* set as high priority, and protect from OOM killer */
setpriority(PRIO_PROCESS, 0, -20);
FILE* oom_adj = fopen("/proc/self/oom_score_adj", "we");
if (oom_adj) {
fputs("-1000", oom_adj);
fclose(oom_adj);
} else {
/* fallback to kernels <= 2.6.35 */
oom_adj = fopen("/proc/self/oom_adj", "we");
if (oom_adj) {
fputs("-17", oom_adj);
fclose(oom_adj);
}
}
/* parse arguments */
//解析各种参数
int c;
while ((c = getopt(argc, argv, "dho:svqzpPBRSV:")) != -1) {
switch (c) {
// clang-format off
case 'd': do_add_date = 1; break;
case 'z': do_zip_file = 1; break;
case 'o': use_outfile = optarg; break;
case 's': use_socket = 1; break;
case 'S': use_control_socket = 1; break;
case 'v': show_header_only = true; break;
case 'q': do_vibrate = 0; break;
case 'p': do_fb = 1; break;
case 'P': ds.update_progress_ = true; break;
case 'R': is_remote_mode = 1; break;
case 'B': do_broadcast = 1; break;
case 'V': break; // compatibility no-op
case 'h':
ShowUsageAndExit(0);
break;
default:
fprintf(stderr, "Invalid option: %c\n", c);
ShowUsageAndExit();
// clang-format on
}
}
...
// If we are going to use a socket, do it as early as possible to avoid timeouts from bugreport.
//如果我们要使用套接字，请尽早执行，以避免在bugreport出现超时
if (use_socket) {
redirect_to_socket(stdout, "dumpstate");
}
/* 读取/proc/cmdline */
FILE *cmdline = fopen("/proc/cmdline", "re");
if (cmdline) {
fgets(cmdline_buf, sizeof(cmdline_buf), cmdline);
fclose(cmdline);
}
ds.PrintHeader();//打印头部信息
if (telephony_only) {
//...不执行这
} else {
// Dumps systrace right away, otherwise it will be filled with unnecessary events.
// First try to dump anrd trace if the daemon is running. Otherwise, dump
// the raw trace.
//在dump_traces（）之前调用以下dumpsys调用保持系统统计信息尽可能接近其初始状态。
if (!dump_anrd_trace()) {
dump_systrace();
}
// TODO: Drop root user and move into dumpstate() once b/28633932 is fixed.
dump_raft();
//collect stack traces from Dalvik and native processes (needs root)
dump_traces_path = dump_traces();
dumpstate();//核心
}
...
//通过广播处理发送给ActivityManager一些东西
}
static void dumpstate() {
DurationReporter duration_reporter("DUMPSTATE");
dump_dev_files("TRUSTY VERSION", "/sys/bus/platform/drivers/trusty", "trusty_version");
//记录系统运行时长和休眠时长
RunCommand("UPTIME", {"uptime"});
//输出mmcblk0设备信息
dump_files("UPTIME MMC PERF", mmcblk0, skip_not_stat, dump_stat_from_fd);
dump_emmc_ecsd("/d/mmc0/mmc0:0001/ext_csd");
//内存信息
DumpFile("MEMORY INFO", "/proc/meminfo");
//Cpu信息
RunCommand("CPU INFO", {"top", "-b", "-n", "1", "-H", "-s", "6", "-o",
"pid,tid,user,pr,ni,%cpu,s,virt,res,pcy,cmd,name"});
...
//输出kernel log
do_dmesg();
//所有已打开文件
RunCommand("LIST OF OPEN FILES", {"lsof"}, CommandOptions::AS_ROOT);
...
//打印SYSTEM LOG，EVENT LOG，RADIO LOG，LOG STATISTICS，LAST LOGCAT
DoLogcat();
...
//Binder log
/* Binder state is expensive to look at as it uses a lot of memory. */
DumpFile("BINDER FAILED TRANSACTION LOG", "/sys/kernel/debug/binder/failed_transaction_log");
DumpFile("BINDER TRANSACTION LOG", "/sys/kernel/debug/binder/transaction_log");
DumpFile("BINDER TRANSACTIONS", "/sys/kernel/debug/binder/transactions");
DumpFile("BINDER STATS", "/sys/kernel/debug/binder/stats");
DumpFile("BINDER STATE", "/sys/kernel/debug/binder/state");
...
printf("========================================================\n");
printf("== Running Application Activities\n");
printf("========================================================\n");
//dumpsys activity 的log
RunDumpsys("APP ACTIVITIES", {"activity", "-v", "all"});
printf("========================================================\n");
printf("== Running Application Services\n");
printf("========================================================\n");
RunDumpsys("APP SERVICES", {"activity", "service", "all"});
printf("========================================================\n");
printf("== Running Application Providers\n");
printf("========================================================\n");
RunDumpsys("APP PROVIDERS", {"activity", "provider", "all"});
printf("========================================================\n");
printf("== Dropbox crashes\n");
printf("========================================================\n");
RunDumpsys("DROPBOX SYSTEM SERVER CRASHES", {"dropbox", "-p", "system_server_crash"});
RunDumpsys("DROPBOX SYSTEM APP CRASHES", {"dropbox", "-p", "system_app_crash"});
// DumpModemLogs adds the modem logs if available to the bugreport.
// Do this at the end to allow for sufficient time for the modem logs to be
// collected.
DumpModemLogs();
printf("========================================================\n");
printf("== Final progress (pid %d): %d/%d (estimated %d)\n", ds.pid_, ds.progress_->Get(),
ds.progress_->GetMax(), ds.progress_->GetInitialMax());
printf("========================================================\n");
printf("== dumpstate: done (id %d)\n", ds.id_);
printf("========================================================\n");
}
所以核心在
static void DoLogcat() {
unsigned long timeout;
// DumpFile("EVENT LOG TAGS", "/etc/event-log-tags");
// calculate timeout
timeout = logcat_timeout("main") + logcat_timeout("system") + logcat_timeout("crash");
if (timeout < 20000) {
timeout = 20000;
}
RunCommand("SYSTEM LOG",
{"logcat", "-v", "threadtime", "-v", "printable", "-v", "uid",
"-d", "*:v"},
CommandOptions::WithTimeout(timeout / 1000).Build());
timeout = logcat_timeout("events");
if (timeout < 20000) {
timeout = 20000;
}
RunCommand("EVENT LOG",
{"logcat", "-b", "events", "-v", "threadtime", "-v", "printable", "-v", "uid",
"-d", "*:v"},
CommandOptions::WithTimeout(timeout / 1000).Build());
timeout = logcat_timeout("radio");
if (timeout < 20000) {
timeout = 20000;
}
RunCommand("RADIO LOG",
{"logcat", "-b", "radio", "-v", "threadtime", "-v", "printable", "-v", "uid",
"-d", "*:v"},
CommandOptions::WithTimeout(timeout / 1000).Build());
RunCommand("LOG STATISTICS", {"logcat", "-b", "all", "-S"});
/* kernels must set CONFIG_PSTORE_PMSG, slice up pstore with device tree */
RunCommand("LAST LOGCAT",
{"logcat", "-L", "-b", "all", "-v", "threadtime", "-v", "printable", "-v", "uid",
"-d", "*:v"});
}
大概都有：
dumpstate
MEMORY INFO
获取该log:读取文件/proc/meminfo
系统内存使用状态
CPU INFO
获取该log:执行/system/bin/top -n 1 -d 1 -m 30 -t
系统CPU使用状态
PROCRANK
获取该log:执行/system/bin/procrank
执行/system/xbin/procrank后输出的结果,查看一些内存使用状态
VIRTUAL MEMORY STATS
获取该log:读取文件/proc/vmstat
虚拟内存分配情况
vmalloc申请的内存则位于vmalloc_start～vmalloc_end之间，与物理地址没有简单的转换关系，虽然在逻辑上它们也是连续的，但是在物理上它们不要求连续。
VMALLOC INFO
获取该log:读取文件/proc/vmallocinfo
虚拟内存分配情况
SLAB INFO
获取该log:读取文件/proc/slabinfo
SLAB是一种内存分配器.这里输出该分配器的一些信息
ZONEINFO
获取该log:读取文件/proc/zoneinfo
zone info
SYSTEM LOG(需要着重分析)
获取该log:执行/system/bin/logcat -v time -d *:v
会输出在程序中输出的Log,用于分析系统的当前状态
VM TRACES
获取该log:读取文件/data/anr/traces.txt
因为每个程序都是在各自的VM中运行的,这个Log是现实各自VM的一些traces
EVENT LOG TAGS
获取该log:读取文件/etc/event-log-tags
EVENT LOG
获取该log:执行/system/bin/logcat -b events -v time -d *:v
输出一些Event的log
RADIO LOG
获取该log:执行/system/bin/logcat -b radio -v time -d *:v
显示一些无线设备的链接状态,如GSM，PHONE,STK(Satellite Tool Kit)…
NETWORK STATE
获取该log:执行/system/bin/netcfg (得到网络链接状态)
获取该log:读取文件/proc/net/route (得到路由状态)
显示网络链接和路由
SYSTEM PROPERTIES
获取该log:参考代码实现
显示一些系统属性,如Version,Services,network…
KERNEL LOG
获取该log:执行/system/bin/dmesg
显示Android内核输出的Log
KERNEL WAKELOCKS
获取该log:读取文件/proc/wakelocks
内核对一些程式和服务唤醒和休眠的一些记录
KERNEL CPUFREQ
(Linux kernel CPUfreq subsystem) Clock scaling allows you to change the clock speed of the CPUs on the fly.
This is a nice method to save battery power, because the lower the clock speed is, the less power the CPU consumes.
PROCESSES
获取该log:执行ps -P
显示当前进程
PROCESSES AND THREADS
获取该log:执行ps -t -p -P
显示当前进程和线程
LIBRANK
获取该log:执行/system/xbin/librank
剔除不必要的library
BINDER FAILED TRANSACTION LOG
获取该log:读取文件/proc/binder/failed_transaction_log
BINDER TRANSACTION LOG
获取该log:读取文件/proc/binder/transaction_log
BINDER TRANSACTIONS
获取该log:读取文件/proc/binder/transactions
BINDER STATS
获取该log:读取文件/proc/binder/stats
BINDER PROCESS STATE
获取该log:读取文件/proc/binder/proc/*
bind相关的一些状态
FILESYSTEMS
获取该log:执行/system/bin/df
主要文件的一些容量使用状态(cache,sqlite,dev…)
PACKAGE SETTINGS
获取该log:读取文件/data/system/packages.xml
系统中package的一些状态(访问权限,路径…)，类似Windows里面的一些lnk文件吧.
PACKAGE UID ERRORS
获取该log:读取文件/data/system/uiderrors.txt
错误信息
KERNEL LAST KMSG LOG
最新kernel message log
LAST RADIO LOG
最新radio log
KERNEL PANIC CONSOLE LOG
KERNEL PANIC THREADS LOG
控制台/线程的一些错误信息log
BACKLIGHTS
获取该log:获取LCD brightness读/sys/class/leds/lcd-backlight/brightness
获取该log:获取Button brightness读/sys/class/leds/button-backlight/brightness
获取该log:获取Keyboard brightness读/sys/class/leds/keyboard-backlight/brightness
获取该log:获取ALS mode读/sys/class/leds/lcd-backlight/als
获取该log:获取LCD driver registers读/sys/class/leds/lcd-backlight/registers
获取相关亮度的一些信息
(2)build.prop
VERSION INFO输出下列信息
当前时间
当前内核版本:可以读取文件(/proc/version)获得
显示当前命令:可以读取文件夹(/proc/cmdline)获得
显示系统build的一些属性:可以读取文件(/system/build.prop)获得
输出系统一些属性
gsm.version.ril-impl
gsm.version.baseband
gsm.imei
gsm.sim.operator.numeric
gsm.operator.alpha
(3)dumpsys
执行/system/bin/dumpsys后可以获得这个log.
经常会发现该log输出不完整,因为代码里面要求该工具最多只执行60ms,可能会导致log无法完全输出来.
可以通过修改时间参数来保证log完全输出.
信息:
Currently running services
DUMP OF SERVICE services-name(running)