Function start_async_exec

modules/exec/exec.c:172–245

int start_async_exec(struct sip_msg* msg, str* command, str* input,
													pv_spec_t *outvar, int *fd)
{
	pid_t pid;
	FILE *pin = NULL, *pout = NULL;
	int val;

	if ((input&&input->s&&input->len) || outvar) {
		pid =  __popen3(command->s, (input&&input->s&&input->len) ? &pin : NULL,
									outvar ? &pout : NULL,
									NULL);
	} else {
		pid = fork();
		if (pid == 0) {
			/* child process*/
			execl("/bin/sh", "/bin/sh", "-c", command->s, NULL);
			exit(-1);
		}
		if (pid<0) {
			/*error of fork*/
			LM_ERR("failed to fork (%s)\n",strerror(errno));
			goto error;
		}
	}

	if (input && input->len && pin) {
		if ( (val=fwrite(input->s, 1, input->len, pin)) != input->len) {
			LM_ERR("failed to write all (%d needed, %d written) to input pipe,"
				" but continuing\n",input->len,val);
		}

		if (ferror(pin)) {
			LM_ERR("failure detected (%s), continuing..\n",strerror(errno));
		}
		fclose(pin);
	}

	/* set time to kill on the new process */
	schedule_to_kill(pid);

	if (outvar==NULL) {
		/* nothing to wait for, no I/O */
		return 2;
	}

	/* prepare the read FD and make it non-blocking */
	if ( (*fd=dup( fileno( pout ) ))<0 ) {
		LM_ERR("dup failed: (%d) %s\n", errno, strerror(errno));
		goto error;
	}
	val = fcntl( *fd, F_GETFL);
	if (val==-1){
		LM_ERR("fcntl failed: (%d) %s\n", errno, strerror(errno));
		goto error2;
	}
	if (fcntl( *fd , F_SETFL, val|O_NONBLOCK)==-1){
		LM_ERR("set non-blocking failed: (%d) %s\n",
			errno, strerror(errno));