Ejemplo n.º 1
0
/** Determine if we're running under a debugger by attempting to attach using pattach
 *
 * @return 0 if we're not, 1 if we are, -1 if we can't tell because of an error,
 *	-2 if we can't tell because we don't have the CAP_SYS_PTRACE capability.
 */
static int fr_get_debug_state(void)
{
	int pid;

	int from_child[2] = {-1, -1};

#ifdef HAVE_CAPABILITY_H
	cap_flag_value_t value;
	cap_t current;

	/*
	 *  If we're running under linux, we first need to check if we have
	 *  permission to to ptrace. We do that using the capabilities
	 *  functions.
	 */
	current = cap_get_proc();
	if (!current) {
		fr_strerror_printf("Failed getting process capabilities: %s", fr_syserror(errno));
		return DEBUG_STATE_UNKNOWN;
	}

	if (cap_get_flag(current, CAP_SYS_PTRACE, CAP_PERMITTED, &value) < 0) {
		fr_strerror_printf("Failed getting permitted ptrace capability state: %s",
				   fr_syserror(errno));
		cap_free(current);
		return DEBUG_STATE_UNKNOWN;
	}

	if ((value == CAP_SET) && (cap_get_flag(current, CAP_SYS_PTRACE, CAP_EFFECTIVE, &value) < 0)) {
		fr_strerror_printf("Failed getting effective ptrace capability state: %s",
				   fr_syserror(errno));
		cap_free(current);
		return DEBUG_STATE_UNKNOWN;
	}

	/*
	 *  We don't have permission to ptrace, so this test will always fail.
	 */
	if (value == CAP_CLEAR) {
		fr_strerror_printf("ptrace capability not set.  If debugger detection is required run as root or: "
				   "setcap cap_sys_ptrace+ep <path_to_radiusd>");
		cap_free(current);
		return DEBUG_STATE_UNKNOWN_NO_PTRACE_CAP;
	}
	cap_free(current);
#endif

	if (pipe(from_child) < 0) {
		fr_strerror_printf("Error opening internal pipe: %s", fr_syserror(errno));
		return DEBUG_STATE_UNKNOWN;
	}

	pid = fork();
	if (pid == -1) {
		fr_strerror_printf("Error forking: %s", fr_syserror(errno));
		return DEBUG_STATE_UNKNOWN;
	}

	/* Child */
	if (pid == 0) {
		int8_t ret = DEBUG_STATE_NOT_ATTACHED;
		int ppid = getppid();

		/* Close parent's side */
		close(from_child[0]);

		/*
		 *	FreeBSD is extremely picky about the order of operations here
		 *	we need to attach, wait *then* write whilst the parent is still
		 *	suspended, then detach, continuing the process.
		 *
		 *	If we don't do it in that order the read in the parent triggers
		 *	a SIGKILL.
		 */
		if (_PTRACE(PT_ATTACH, ppid) == 0) {
			/* Wait for the parent to stop */
			waitpid(ppid, NULL, 0);

			/* Tell the parent what happened */
			if (write(from_child[1], &ret, sizeof(ret)) < 0) {
				fprintf(stderr, "Writing ptrace status to parent failed: %s", fr_syserror(errno));
			}

			/* Detach */
			_PTRACE_DETACH(ppid);
			exit(0);
		}

		ret = DEBUG_STATE_ATTACHED;
		/* Tell the parent what happened */
		if (write(from_child[1], &ret, sizeof(ret)) < 0) {
			fprintf(stderr, "Writing ptrace status to parent failed: %s", fr_syserror(errno));
		}

		exit(0);
	/* Parent */
	} else {
		int8_t ret = DEBUG_STATE_UNKNOWN;

		/*
		 *	The child writes errno (reason) if pattach failed else 0.
		 *
		 *	This read may be interrupted by pattach,
		 *	which is why we need the loop.
		 */
		while ((read(from_child[0], &ret, sizeof(ret)) < 0) && (errno == EINTR));

		/* Close the pipes here (if we did it above, it might race with pattach) */
		close(from_child[1]);
		close(from_child[0]);

		/* Collect the status of the child */
		waitpid(pid, NULL, 0);

		return ret;
	}
}
Ejemplo n.º 2
0
/*
 * Prepare task for parallel debugger attach
 * Returns SLURM_SUCCESS or SLURM_ERROR.
 */
int
pdebug_trace_process(stepd_step_rec_t *job, pid_t pid)
{
	/*  If task to be debugged, wait for it to stop via
	 *  child's ptrace(PTRACE_TRACEME), then SIGSTOP, and
	 *  ptrace(PTRACE_DETACH).
	 */

	if (job->task_flags & TASK_PARALLEL_DEBUG) {
		int status;
		waitpid(pid, &status, WUNTRACED);
		if (!WIFSTOPPED(status)) {
			int i;
			error("pdebug_trace_process WIFSTOPPED false"
			      " for pid %d", pid);
			if (WIFEXITED(status)) {
				error("Process %d exited \"normally\""
				      " with return code %d",
				      pid,
				      WEXITSTATUS(status));
			} else if (WIFSIGNALED(status)) {
				error("Process %d killed by signal %d",
				      pid, WTERMSIG(status));
			}

			/*
			 * Mark this process as complete since it died
			 * prematurely.
			 */
			for (i = 0; i < job->node_tasks; i++) {
				if (job->task[i]->pid == pid) {
					job->task[i]->state =
						STEPD_STEP_TASK_COMPLETE;
				}
			}

			return SLURM_ERROR;
		}
		if ((pid > (pid_t) 0) && (kill(pid, SIGSTOP) < 0)) {
			error("kill(%lu): %m", (unsigned long) pid);
			return SLURM_ERROR;
		}

#ifdef BSD
		if (_PTRACE(PT_DETACH, pid, (caddr_t)1, 0)) {
#elif defined(PT_DETACH)
		if (_PTRACE(PT_DETACH, pid, NULL, 0)) {
#elif defined(__sun)
		if (_PTRACE(7, pid, NULL, 0)) {
#elif defined(__CYGWIN__)
		if (1) {
			debug3("No ptrace for cygwin");
		} else {
#else
		if (_PTRACE(PTRACE_DETACH, pid, NULL, 0)) {
#endif
			error("ptrace(%lu): %m", (unsigned long) pid);
			return SLURM_ERROR;
		}
	}
	return SLURM_SUCCESS;
}

/*
 * Stop current task on exec() for connection from a parallel debugger
 */
void
pdebug_stop_current(stepd_step_rec_t *job)
{
	/*
	 * Stop the task on exec for TotalView to connect
	 */
	if ( (job->task_flags & TASK_PARALLEL_DEBUG)
#ifdef BSD
	     && (_PTRACE(PT_TRACE_ME, 0, (caddr_t)0, 0) < 0) )
#elif defined(PT_TRACE_ME)
	     && (_PTRACE(PT_TRACE_ME, 0, NULL, 0) < 0) )
#elif defined(__sun)
	     && (_PTRACE(0, 0, NULL, 0) < 0))
#elif defined(__CYGWIN__)
	     && 0)
#else
	     && (_PTRACE(PTRACE_TRACEME, 0, NULL, 0) < 0) )
#endif
		error("ptrace: %m");
}

/* Check if this PID should be woken for TotalView partitial attach */
static bool _pid_to_wake(pid_t pid)
{
#ifdef CLONE_PTRACE
	char proc_stat[1024], proc_name[22], state[1], *str_ptr;
	int len, proc_fd, ppid, pgrp, session, tty, tpgid;
	long unsigned flags;

	sprintf (proc_name, "/proc/%d/stat", (int) pid);
	if ((proc_fd = open(proc_name, O_RDONLY, 0)) == -1)
		return false;  /* process is now gone */
	len = read(proc_fd, proc_stat, sizeof(proc_stat));
	close(proc_fd);
	if (len < 14)
		return false;
	/* skip over "PID (CMD) " */
	if ((str_ptr = (char *)strrchr(proc_stat, ')')) == NULL)
		return false;
	if (sscanf(str_ptr + 2,
		   "%c %d %d %d %d %d %lu ",
		   state, &ppid, &pgrp, &session, &tty, &tpgid, &flags) != 7)
		return false;
	if ((flags & CLONE_PTRACE) == 0)
		return true;
	return false;
#else
	int status;

	waitpid(pid, &status, (WUNTRACED | WNOHANG));
	if (WIFSTOPPED(status))
		return true;
	return false;
#endif
}

/*
 * Wake tasks currently stopped for parallel debugger attach
 */
void pdebug_wake_process(stepd_step_rec_t *job, pid_t pid)
{
	if ((job->task_flags & TASK_PARALLEL_DEBUG) && (pid > (pid_t) 0)) {
		if (_pid_to_wake(pid)) {
			if (kill(pid, SIGCONT) < 0)
				error("kill(%lu): %m", (unsigned long) pid);
			else
				debug("woke pid %lu", (unsigned long) pid);
		} else {
			debug("pid %lu not stopped", (unsigned long) pid);
		}
	}
}