跟踪Android callback 调用堆栈

0 在调试 android  系统时可以通过打印调用堆栈 callback stack 来分析和解决android问题。

1 java 层打印callback stack 可以通过 catch exception 然后 使用 Log.w(LOGTAG, Log.getStackTraceString(throwable)) 打印调用堆栈

Throwable throwable = new Throwable();   
        Log.w(LOGTAG, Log.getStackTraceString(throwable));
或者

            try {
                wait();
            } catch (InterruptedException e) {
                Log.e(LOGTAG, "Caught exception while waiting for overrideUrl");
                Log.e(LOGTAG, Log.getStackTraceString(e));
            }

2 c/c++, 通常情况下,可以通过segment fault 等错误即信号 SIGSEGV(11) 做出相应处理,即设置SIGSEGV的handler调用libc的backtrace,即可打印对于的callback stack;定位问题所在;但在android 中, bionic 不提供类似功能,而且只能通过logcat才能看到log信息,但是我们也可以根据android出错信息获得调用堆栈信息,如以下出错信息:

    D/CallStack( 2029): #00  pc 00008156  /system/lib/hw/audio.primary.tf4.so
    D/CallStack( 2029): #01  pc 000089e8  /system/lib/hw/audio.primary.tf4.so (android_audio_legacy::AudioHardware::AudioStreamOutALSA::setParameters(android::String const&)+139)
    D/CallStack( 2029): #02  pc 0000b2ca  /system/lib/hw/audio.primary.tf4.so
    D/CallStack( 2029): #03  pc 0003ac6a  /system/lib/libaudioflinger.so (android::AudioFlinger::MixerThread::checkForNewParameters_l()+377)
    D/CallStack( 2029): #04  pc 0003960a  /system/lib/libaudioflinger.so (android::AudioFlinger::PlaybackThread::threadLoop()+145)
    D/CallStack( 2029): #05  pc 00011264  /system/lib/libutils.so (android::Thread::_threadLoop(void*)+111)
    D/CallStack( 2029): #06  pc 00010dca  /system/lib/libutils.so
    D/CallStack( 2029): #07  pc 0000e3f8  /system/lib/libc.so (__thread_entry+72)
    D/CallStack( 2029): #08  pc 0000dae4  /system/lib/libc.so (pthread_create+160)
2.1 可以使用 arm-linux-addr2line 获得调用堆栈,arm-eabi-addr2line -C -f -e symbols/system/lib/*.so addr, 这样就可以打印出 调用堆栈信息了。

2.2 使用ndk-stack 工具, 保存出错log为 logcat.log, cat logcat..log | ndk-stack -sym ~/[SOURCE-DIR]/out/target/product/[PROJECT]/symbols/system/lib/ 打印调用堆栈

2.3 使用 panic.py(代码在下面) 脚本分析并打印调用堆栈,/panic.py logcat.log, 注意logcat 必须转换成以下格式

    D/CallStack( 2029): #00  pc 00008156  /system/lib/hw/audio.primary.tf4.so
    D/CallStack( 2029): #01  pc 000089e8  /system/lib/hw/audio.primary.tf4.so
    D/CallStack( 2029): #02  pc 0000b2ca  /system/lib/hw/audio.primary.tf4.so
    D/CallStack( 2029): #03  pc 0003ac6a  /system/lib/libaudioflinger.so
    D/CallStack( 2029): #04  pc 0003960a  /system/lib/libaudioflinger.so
    D/CallStack( 2029): #05  pc 00011264  /system/lib/libutils.so
    D/CallStack( 2029): #06  pc 00010dca  /system/lib/libutils.so
    D/CallStack( 2029): #07  pc 0000e3f8  /system/lib/libc.so
    D/CallStack( 2029): #08  pc 0000dae4  /system/lib/libc.so
这样执行脚本 ./panic.py setincallpath_l.txt, 打印定位信息:
    w@w:/meizu/JellyBean-4.2.1/trunk/out/target/product/tf4$ ./panic.py ./backtrack/setincall_path.txt
    read file ok
    AudioHardware.cpp:829         android_audio_legacy::AudioHardware::setIncallPath_l(unsigned int)
    AudioHardware.cpp:1537        android_audio_legacy::AudioHardware::AudioStreamOutALSA::setParameters(android::String8 const&)
    audio_hw_hal.cpp:197          out_set_parametersAudioFlinger.cpp:3535         android::AudioFlinger::MixerThread::checkForNewParameters_l()
    AudioFlinger.cpp:2586         android::AudioFlinger::PlaybackThread::threadLoop()
    Threads.cpp:793               android::Thread::_threadLoop(void*)
    Threads.cpp:132               thread_data_t::trampoline(thread_data_t const*)
    pthread.c:204                 __thread_entry
    pthread.c:348                 pthread_create
2.4 google提供了一个python脚本,可以从 http://code.google.com/p/android-ndk-stacktrace-analyzer/ 下载这个python脚本,然后使用
adb logcat -d > logfile 导出 crash 的log,
使用 arm-eabi-objdump (位于build/prebuilt/linux-x86/arm-eabi-4.2.1/bin下面)把so或exe转换成汇编代码,如:
arm-eabi-objdump -S mylib.so > mylib.asm,
然后使用脚本
python parse_stack.py <asm-file> <logcat-file>

panic.py 需要设置环境,如下:

#!/usr/bin/python
# stack symbol parser

import os
import string
import sys

#define android product name
#ANDROID_PRODUCT_NAME = 'generic'
ANDROID_PRODUCT_NAME = 'ok'

ANDROID_WORKSPACE = os.getcwd()+"/"

# addr2line tool path and symbol path
addr2line_tool = 'arm-linux-addr2line'
symbol_dir = ANDROID_WORKSPACE + '/symbols'
symbol_bin = symbol_dir + '/system/bin/'
symbol_lib = symbol_dir + '/system/lib/'

class ReadLog:
    def __init__(self,filename):
        self.logname = filename
    def parse(self):
        f = file(self.logname,'r')
        lines = f.readlines()
        if lines != []:
            print 'read file ok'
        else:
            print 'read file failed'
        result =[]
        for line in lines:
            if line.find('stack') != -1:
                print 'stop search'
                break
            elif line.find('system') != -1:
                #print 'find one item' + line
                result.append(line)
        return result

class ParseContent:
    def __init__(self,addr,lib):
            self.address = addr # pc address
            self.exename = lib  # executable or shared library
    def addr2line(self):
        cmd = addr2line_tool + " -C -f -s -e " + symbol_dir + self.exename + " " + self.address
        #print cmd
        stream = os.popen(cmd)
        lines = stream.readlines();
        list = map(string.strip,lines)
        return list
    
inputarg = sys.argv
if len(inputarg) < 2:
    print 'Please input panic log'
    exit()

filename = inputarg[1]
readlog = ReadLog(filename)
inputlist = readlog.parse()

for item in inputlist:
    itemsplit = item.split()
    test = ParseContent(itemsplit[-2],itemsplit[-1])
    list = test.addr2line()
    print "%-30s%s" % (list[1],list[0])

3 出了上述系统主动输出出错信息,我们还可以通过代码在系统不出错的情况下,打印调用信息,然后通过panic.py 打印调用堆栈

3.1 在cpp文件添加如下信息

    #include <utils/CallStack.h>
    ...
    status_t AudioHardware::setIncallPath_l(uint32_t device) {
    ...
    #ifdef _ARM_
        android::CallStack stack;
        stack.update(1, 100);
        stack.dump("");
    #endif
    ...
    }
3.2 在Android.mk中,加入:
    LOCAL_CFLAGS += -D_ARM_
    LOCAL_SHARED_LIBRARIES += libutils

这样将会打印上面所述的调用信息,便于分析代码,debug,定位问题。








 

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