lldb attach to parent hang

run-lldb.sh

#! /bin/sh

exec /Applications/Xcode.app/Contents/Developer/usr/bin/lldb --debug --batch --no-lldbinit --attach-pid $1 --source /tmp/aleksey.txt < /dev/null 2>&1

self-reporter.c

#include <fcntl.h>
#include <sys/errno.h>
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

int
main (void)
{
	const char *commands_filename = "/tmp/aleksey.txt";
	
	int commands_handle = open (commands_filename, O_TRUNC | O_WRONLY | O_CREAT, S_IWUSR | S_IRUSR | S_IRGRP | S_IROTH);
	if (commands_handle < 0) {
		printf ("open failed: %s\n", strerror (errno));
		return 1;
	}
	pid_t self_pid = getpid ();
	//dprintf (commands_handle, "process attach --pid %ld\n", (long) self_pid);
	dprintf (commands_handle, "thread list\n");
	dprintf (commands_handle, "thread backtrace all\n");
	dprintf (commands_handle, "detach\n");
	dprintf (commands_handle, "quit\n");
	close (commands_handle);

	char pid_str[50];
	sprintf (pid_str, "%ld", (long) self_pid);

	pid_t child_pid = fork ();
	if (child_pid == 0) {
		const char *args[] = {
			"/Applications/Xcode.app/Contents/Developer/usr/bin/lldb",
			"--debug",
			"--no-use-colors",
			"--batch",
			"--no-lldbinit",
			"--attach-pid",
			pid_str,
			"--source",
			commands_filename,
			(char*)0
		};
#if 0
		const char *args[] = {
			"./run-lldb.sh",
			pid_str,
			(char*)0
		};
#endif
#if 0
		pid_t pid2 = fork ();
		if (pid2 < 0) {
			perror ("fork 2");
			_exit (1);
		} else if (pid2 > 0)
			_exit (0);
#else
		if (setsid () < 0)
			perror ("setsid");
#endif
		//if (setpgid (0,0) < 0)
		//	perror ("setpgid");
		signal (SIGTTIN, SIG_IGN);
		signal (SIGTTOU, SIG_IGN);
		signal (SIGTSTP, SIG_IGN);
		signal (SIGHUP, SIG_IGN);
		dup2 (STDERR_FILENO, STDOUT_FILENO);
		close (STDIN_FILENO);
		printf ("running lldb\n");
		execv (args[0], (char**)args);
		printf ("exec failed: %s\n", strerror (errno));
		_exit (-1);
	} else if (child_pid > 0) {
		int status;
		//setpgid (child_pid, child_pid);
		printf ("sleeping for 10 seconds in the parent\n");
		sleep (10);
		printf ("waiting in parent\n");
		waitpid (child_pid, &status, 0);
		printf ("woke in parent\n");
		while (0) {
			int i;
			printf ("ping\n");
			for (i = 0; i < 12345678; ++i) {
				//if (i % 500000 == 0)
				//	printf ("ping\n");
			}
			sleep (5);
		}
		return 0;
	} else {
		printf ("fork failed: %s\n", strerror (errno));
		return 1;
	}
}