一般察看函数运行时堆栈的方法是使用GDB（bt命令）之类的外部调试器,但是,有些时候为了分析程序的BUG,(主要针对长时间运行程序的分析),在程序出错时打印出函数的调用堆栈是非常有用的。

在glibc头文件"execinfo.h"中声明了三个函数用于获取当前线程的函数调用堆栈。

int backtrace(void **buffer,int size)

/*judge whether process is exist*/
bool processExists(char * process_name) {
FILE *ptr;
int RE_BUF_SIZE = 32;
char rebuff[RE_BUF_SIZE];
char ps[128];
snprintf(ps, sizeof(ps), "ps | grep %s |grep -v grep| wc -l", process_name);
if((ptr = popen(ps, "r")) != NULL) {
int count = 0;
fgets(rebuff, RE_BUF_SIZE, ptr);
if(rebuff != NULL) {
count = atoi(rebuff);
}
pclose(ptr);
return count >= 1;
}

printf("Current process %s is not Exist!!!!\n",process_name);
return false;
}

static char *signal_str[] = {
[1] = "SIGHUP", [2] = "SIGINT", [3] = "SIGQUIT", [4] = "SIGILL", [5] = "SIGTRAP",
[6] = "SIGABRT", [7] = "SIGBUS", [8] = "SIGFPE", [9] = "SIGKILL", [10] = "SIGUSR1",
[11] = "SIGSEGV", [12] = "SIGUSR2", [13] = "SIGPIPE", [14] = "SIGALRM", [15] = "SIGTERM",
[16] = "SIGSTKFLT", [17] = "SIGCHLD", [18] = "SIGCONT", [19] = "SIGSTOP", [20] = "SIGTSTP",
[21] = "SIGTTIN", [22] = "SIGTTOU", [23] = "SIGURG", [24] = "SIGXCPU", [25] = "SIGXFSZ",
[26] = "SIGVTALRM", [27] = "SIGPROF", [28] = "SIGWINCH", [29] = "SIGIO", [30] = "SIGPWR",
[31] = "SIGSYS", [34] = "SIGRTMIN", [35] = "SIGRTMIN+1", [36] = "SIGRTMIN+2", [37] = "SIGRTMIN+3",
[38] = "SIGRTMIN+4", [39] = "SIGRTMIN+5", [40] = "SIGRTMIN+6", [41] = "SIGRTMIN+7", [42] = "SIGRTMIN+8",
[43] = "SIGRTMIN+9", [44] = "SIGRTMIN+10", [45] = "SIGRTMIN+11", [46] = "SIGRTMIN+12", [47] = "SIGRTMIN+13",
[48] = "SIGRTMIN+14", [49] = "SIGRTMIN+15", [50] = "SIGRTMAX-14", [51] = "SIGRTMAX-13", [52] = "SIGRTMAX-12",
[53] = "SIGRTMAX-11", [54] = "SIGRTMAX-10", [55] = "SIGRTMAX-9", [56] = "SIGRTMAX-8", [57] = "SIGRTMAX-7",
[58] = "SIGRTMAX-6", [59] = "SIGRTMAX-5", [60] = "SIGRTMAX-4", [61] = "SIGRTMAX-3", [62] = "SIGRTMAX-2",
[63] = "SIGRTMAX-1", [64] = "SIGRTMAX",
};

void sig_handler(int signo)
{
char cmd[64] = {};
void *array[10];
int size = 0;
char **strings = NULL;
int i = 0;

#if 0
printf("\n\n[%s: %d] bitbox crashed by signal %s.\n", __func__, __LINE__, signal_str[signo]);

printf("Call Trace:\n");
size = backtrace(array, 10);
strings = backtrace_symbols(array, size);
if (strings) {
for (i = 0; i < size; i++)
printf (" %s\n", strings[i]);
free (strings);
} else {
printf("Not Found\n\n");
}

if (signo == SIGSEGV || signo == SIGBUS ||
signo == SIGTRAP || signo == SIGABRT) {
sprintf(cmd, "cat /proc/%d/maps", getpid());
printf("Process maps:\n");
system(cmd);
}
#else
wdt_stop_count();
#endif

exit(-1);
}

int main(int argc, char **argv)
{
int c = -1;
int daemonize = 0;
printf("watchdog V1.7 start!!!!@_@\n");

signal(SIGPIPE, SIG_IGN);
signal(SIGINT, sig_handler);
signal(SIGTERM, sig_handler);
signal(SIGBUS, sig_handler);
signal(SIGSEGV, sig_handler);
signal(SIGABRT, sig_handler);

while (1) {
c = getopt(argc, argv, "bBf:h");
if (c < 0)
break;
switch (c) {
case 'b':
case 'B':
daemonize = 1;
break;
case 'f':
break;
case 'h':

return 0;
default:
return -1;
}
}

/* run in the background */
if (daemonize) {
if (daemon(0, 1)) {
perror("daemon");
return -1;
}
}

}