am 02526d48: debuggerd: properly unblock signal handler. (54175579) · Commits · e / os / android_system_core

debuggerd/debuggerd.c

+13 −1

Original line number	Diff line number	Diff line
		@@ -642,7 +642,7 @@ static void handle_crashing_process(int fd)
		goto done;
		}

		sprintf(buf,"/proc/%d/task/%d", cr.pid, tid);
		snprintf(buf, sizeof buf, "/proc/%d/task/%d", cr.pid, tid);
		if(stat(buf, &s)) {
		LOG("tid %d does not exist in pid %d. ignoring debug request\n",
		tid, cr.pid);
		@@ -652,7 +652,19 @@ static void handle_crashing_process(int fd)

		XLOG("BOOM: pid=%d uid=%d gid=%d tid=%d\n", cr.pid, cr.uid, cr.gid, tid);

		/* Note that at this point, the target thread's signal handler
		* is blocked in a read() call. This gives us the time to PTRACE_ATTACH
		* to it before it has a chance to really fault.
		*
		* After the attach, the thread is stopped, and we write to the file
		* descriptor to ensure that it will run as soon as we call PTRACE_CONT
		* below. See details in bionic/libc/linker/debugger.c, in function
		* debugger_signal_handler().
		*/
		tid_attach_status = ptrace(PTRACE_ATTACH, tid, 0, 0);

		TEMP_FAILURE_RETRY(write(fd, &tid, 1));

		if(tid_attach_status < 0) {
		LOG("ptrace attach failed: %s\n", strerror(errno));
		goto done;