Add to the end of a doubly linked list

main.c

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

typedef struct Node {
    int x;
    struct Node* next;
    struct Node* prev;
} Node;

void deallocate(Node** tail, Node** head) {
    if (*tail == NULL) {
        return;
    }
    
    Node* curr = *tail;
    while (curr->next != NULL) {
        curr = curr->next;
        free(curr->prev);
    }
    free(curr);
    
    *tail = NULL;
    *head = NULL;
}

void insert_beginning(Node** tail, Node** head, int value) {
    Node* new_node = malloc(sizeof(Node));
    if (new_node == NULL) {
        exit(1);
        return;
    }
    
    new_node->x = value;
    new_node->prev = NULL;
    new_node->next = *tail;
    (*tail)->prev = new_node;
    *tail = new_node;
}

void insert_end(Node** tail, Node** head, int value) {
    Node* new_node = malloc(sizeof(Node));
    if (new_node == NULL) {
        exit(3);
        return;
    }
    
    new_node->x = value;
    new_node->next = NULL;
    new_node->prev = *head
    (*head)->next = new_node;
    *head = new_node;
}

void init(Node** tail, Node** head, int value) {
    Node* new_node = malloc(sizeof(int));
    if (new_node == NULL) {
        exit(2);
        return;
    }
    
    new_node->x = value;
    new_node->prev = NULL;
    new_node->next = NULL;
    
    *tail = new_node;
    *head = new_node;
}

int main(int argc, char* argv[]) {
    Node* tail = NULL;
    Node* head = NULL;
    
    init(&tail, &head, 7);
    insert_beginning(&tail, 3);
    insert_beginning(&tail, 1);
    insert_end(&head, 1);

    for (Node* curr = tail; curr != NULL; curr = curr->next) {
        printf("%d ", curr->x);
    }
    
    deallocate(&tail, &head);
    
    return 0;
}