int init_pstree_helper(struct pstree_item *ret)
{
	BUG_ON(!ret->parent);
	ret->pid->state = TASK_HELPER;
	rsti(ret)->clone_flags = CLONE_FILES | CLONE_FS;
	if (shared_fdt_prepare(ret) < 0)
		return -1;
	task_entries->nr_helpers++;
	return 0;
}

static int prep_unix_sk_cwd(struct unix_sk_info *ui, int *prev_cwd_fd, int *prev_root_fd, int *prev_mntns_fd)
{
...
	if (prev_mntns_fd && ui->name[0] && ui->ue->mnt_id >= 0) {
		struct ns_id *mntns = lookup_nsid_by_mnt_id(ui->ue->mnt_id);
                ...
		if (switch_ns_by_fd(ns_fd, &mnt_ns_desc, prev_mntns_fd)) {
			close(ns_fd);
			goto err;
		}
        ...
	}
       ...
}

#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <string.h>
#include <errno.h>
#include <signal.h>
#include <sys/wait.h>

#define SOCKET_PATH "/dev/shm/uds_socket_example"

void create_and_connect(int listen_fd) {
    struct sockaddr_un addr;
    int client_fd = socket(AF_UNIX, SOCK_STREAM, 0);
    if (client_fd == -1) {
        perror("socket");
        exit(EXIT_FAILURE);
    }

    memset(&addr, 0, sizeof(addr));
    addr.sun_family = AF_UNIX;
    strncpy(addr.sun_path, SOCKET_PATH, sizeof(addr.sun_path) - 1);

    if (connect(client_fd, (struct sockaddr*)&addr, sizeof(addr)) == -1) {
        perror("connect");
        close(client_fd);
        exit(EXIT_FAILURE);
    }

    printf("Connected to the server socket. client_fd: %d\n", client_fd);

    pause();
}

int main() {
    int status;
    pid_t pid = fork();

    if (pid == -1) {
        perror("fork");
        exit(EXIT_FAILURE);
    }

    if (pid == 0) {
        int listen_fd = socket(AF_UNIX, SOCK_STREAM, 0);
        if (listen_fd == -1) {
            perror("socket");
            exit(EXIT_FAILURE);
        }

        struct sockaddr_un addr;
        memset(&addr, 0, sizeof(addr));
        addr.sun_family = AF_UNIX;
        strncpy(addr.sun_path, SOCKET_PATH, sizeof(addr.sun_path) - 1);

        unlink(SOCKET_PATH);

        if (bind(listen_fd, (struct sockaddr*)&addr, sizeof(addr)) == -1) {
            perror("bind");
            close(listen_fd);
            exit(EXIT_FAILURE);
        }

        if (listen(listen_fd, 5) == -1) {
            perror("listen");
            close(listen_fd);
            exit(EXIT_FAILURE);
        }

        printf("Child process: pid=%d, pgid=%d\n", getpid(), getpgid(0));

        create_and_connect(listen_fd);
        pause();

        close(listen_fd);
        unlink(SOCKET_PATH);
        exit(EXIT_SUCCESS);
    } else {
        exit(0);
    }

    return 0;
}