GDB로 multiprocess 디버깅할때

Redis의 aof에서  fork하는 부분이 있습니다.

if (server.aof_child_pid != -1) return REDIS_ERR;
    start = ustime();
    if ((childpid = fork()) == 0) {
        char tmpfile[256];

        /* Child */
        if (server.ipfd > 0) close(server.ipfd);
        if (server.sofd > 0) close(server.sofd);
        snprintf(tmpfile,256,"temp-rewriteaof-bg-%d.aof", (int) getpid());
        if (rewriteAppendOnlyFile(tmpfile) == REDIS_OK) {
            exitFromChild(0);
        } else {
            exitFromChild(1);
        }
    } else {
        /* Parent */
        server.stat_fork_time = ustime()-start;
        if (childpid == -1) {
            redisLog(REDIS_WARNING,
                "Can't rewrite append only file in background: fork: %s",
                strerror(errno));
            return REDIS_ERR;
        }
        redisLog(REDIS_NOTICE,
            "Background append only file rewriting started by pid %d",childpid);
        server.aof_rewrite_scheduled = 0;
        server.aof_rewrite_time_start = time(NULL);
        server.aof_child_pid = childpid;
        updateDictResizePolicy();
        /* We set appendseldb to -1 in order to force the next call to the
* feedAppendOnlyFile() to issue a SELECT command, so the differences
* accumulated by the parent into server.aof_rewrite_buf will start
* with a SELECT statement and it will be safe to merge. */
        server.aof_selected_db = -1;
        return REDIS_OK;
    }

구글한테 물어보니 다음과 같은 모드가 있었네요.

set follow-fork-mode mode

Set the debugger response to a program call of fork or vfork.
A call to fork or vfork creates a new process. The mode argument can be:

parent

        The original process is debugged after a fork. The child process runs unimpeded. This is the default.

child

        The new process is debugged after a fork. The parent process runs unimpeded.

 

show follow-fork-mode

        Display the current debugger response to a fork or vfork call.

 

동시에 두개를 볼 수 는 없나봅니다.(child / parent) 생각해보니 두개 동시에 보면 디버깅 하는 입장에서 더 괴롭겠어요 ㅋㅋ

혹시 동시에 두개 하는 방법이 있나요?

 

부지런히 코드 타이핑해서 생각한걸 코드로 뚝딱뚝딱 만들 수 있는 날이 왔으면 좋겠습니다 : )

 

 

GDB모드 원문 url : http://sunsite.ualberta.ca/Documentation/Gnu/gdb-5.0/html_node/gdb_25.html