int run_helper()

in os-Linux/helper.c [42:111]
59 lines of code
9 McCabe index (conditional complexity)

int run_helper(void (*pre_exec)(void *), void *pre_data, char **argv)
{
	struct helper_data data;
	unsigned long stack, sp;
	int pid, fds[2], ret, n;

	stack = alloc_stack(0, __cant_sleep());
	if (stack == 0)
		return -ENOMEM;

	ret = socketpair(AF_UNIX, SOCK_STREAM, 0, fds);
	if (ret < 0) {
		ret = -errno;
		printk(UM_KERN_ERR "run_helper : pipe failed, errno = %d\n",
		       errno);
		goto out_free;
	}

	ret = os_set_exec_close(fds[1]);
	if (ret < 0) {
		printk(UM_KERN_ERR "run_helper : setting FD_CLOEXEC failed, "
		       "ret = %d\n", -ret);
		goto out_close;
	}

	sp = stack + UM_KERN_PAGE_SIZE;
	data.pre_exec = pre_exec;
	data.pre_data = pre_data;
	data.argv = argv;
	data.fd = fds[1];
	data.buf = __cant_sleep() ? uml_kmalloc(PATH_MAX, UM_GFP_ATOMIC) :
					uml_kmalloc(PATH_MAX, UM_GFP_KERNEL);
	pid = clone(helper_child, (void *) sp, CLONE_VM, &data);
	if (pid < 0) {
		ret = -errno;
		printk(UM_KERN_ERR "run_helper : clone failed, errno = %d\n",
		       errno);
		goto out_free2;
	}

	close(fds[1]);
	fds[1] = -1;

	/*
	 * Read the errno value from the child, if the exec failed, or get 0 if
	 * the exec succeeded because the pipe fd was set as close-on-exec.
	 */
	n = read(fds[0], &ret, sizeof(ret));
	if (n == 0) {
		ret = pid;
	} else {
		if (n < 0) {
			n = -errno;
			printk(UM_KERN_ERR "run_helper : read on pipe failed, "
			       "ret = %d\n", -n);
			ret = n;
		}
		CATCH_EINTR(waitpid(pid, NULL, __WALL));
	}

out_free2:
	kfree(data.buf);
out_close:
	if (fds[1] != -1)
		close(fds[1]);
	close(fds[0]);
out_free:
	free_stack(stack, 0);
	return ret;
}