Question

我的Android应用程序（Java + NDK）报告由0xdeadd00d引起的许多崩溃（信号）。众所周知，它是Dalvik VM中止的简写。这些都不会发生在我的JNI调用中，但是信号处理发生在本地世界中。但是本机崩溃报告通常报告的内容（寄存器，堆栈）对于调试它们没有用处。

有没有办法从本机信号处理程序进入Java调用堆栈？或者转储一部分最近的logcat活动？

Answer 1

解决方案：在信号处理程序中为deadd00d引入一个特殊条件。读取logcat的最后1024个字节，将其插入崩溃日志中。

我正以这种方式得到一些不错的诊断。

//n is the length of the file tail to read
//Returns # of byte read
size_t ReadLogcat(char *Buf, size_t n)
{
    char s[sizeof(s_DataPath) + 30];
    //s_DataPath contains the result of Context.getDir("Data")

    strcpy(s, "logcat -d -f ");
    char *fn = s + strlen(s);
    strcat(s, s_DataPath);
    strcat(s, "/logcat"); //Temp file for the logcat
    size_t r = 0;
    system(s); //Dump the snapshot of the logcat into the file called logcat
    FILE *f = fopen(fn, "r");
    if(f)
    {
        fseek(f, -n, SEEK_END); //We need the end of the file
        r = fread(Buf, 1, n, f);
        fclose(f);
    }
    unlink(fn); //Don't need the logcat file anymore
    return r;
}

static void DumpLogcat(FILE *f)
{
    char Buf[1024];
    size_t r;
    if(r = ReadLogcat(Buf, sizeof(Buf)))
    {
        fputs("\nLogcat:\n", f);
        fwrite(Buf, 1, r, f);
    }
}

void OnSignal(int signal, siginfo_t *si, void *p)
{
    FILE *f = OpenCrashLog(); //opens a file in the data dir; details are irrelevant

    //Lots of data dumping here... Version, stack, registers, etc.
    //...

    if((unsigned)si->si_addr == 0xdeadd00d) //Try and dump some Logcat
        DumpLogcat(f);
}

如何从客户设备中找到相关的deadd00d情况？

1 个答案: