C 语言单链表查询问题？

请老师们帮忙看看，怎么修改下面的代码。能满足我的需求。查询iStaffID是1003时， 期望将 所有1003的记录都返回。

测试数据入如： 1001 张三 123456 1002 李四 123456 1003 曹操 123456 1003 曹植 123456期望查找到员工记录： 1003 曹操 1234561003 曹植 123456

程序跑出来只是有“1003 曹操 123456”

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

struct list {
    void *Data;  //存放数据的地址
    struct list *next;
};

struct staff {
    int iStaffID;
    char acName[20];
    char acPasswd[10];
};

// 打印回调函数
void staff_printf(void *data) {
    struct staff *people = (struct staff*)data;
    printf("%5d%10s%10s\n", people->iStaffID,people->acName, people->acPasswd);
}


void list_display_generic(struct list *head, void (*callback)(void *)) {
    struct list *p1 = head->next;
    while (p1 != NULL) {
        void *data = p1->Data;
        callback(data);
        p1 = p1->next;
    }
}

void list_add(struct list *head, void *data) {
    struct list *pNode, *p1 = head;
    pNode = (struct list *)malloc(sizeof(struct list));
    while (p1->next != NULL) {
        p1 = p1->next;
    }

    p1->next = pNode;
    pNode->Data = data;
    pNode->next = NULL;
}

struct list *list_init(void *data) {
    struct list *head;
    head = (struct list *)malloc(sizeof(struct list));
    head->Data = data;
    head->next = NULL;
    return head;
}

// 释放回调函数
void free_staff(void *data) {
    struct staff *people = (struct staff*)data;
    free(people);
}

void list_destroy(struct list *head, void (*callback)(void *)) {
    struct list *p1 = head->next, *p2;
    while (p1 != NULL) {
        p2 = p1;
        void *data = p1->Data;
        callback(data);     //释放存储的数据
        p1 = p1->next;
        free(p2);
    }
    free(head);             //释放头节点所占据的内存
}

// 通用查找函数
void *list_find_generic(struct list *head, void *key, int (*callback)(void *, void *)) {
    struct list *p = head->next;
    while (p != NULL) {
        void *data = p->Data;
        if (callback(data, key) == 1) {
            return data;
        }
        p = p->next;
    }
    return NULL;
}

// 查找回调函数
int staff_id_find(void *data, void *key) {
    struct staff *staff = (struct staff *)data;
    int staff_id = *(int *)key;
    if (staff->iStaffID == staff_id) {
        return 1;
    } else
    return 0;
}

int main() {
    struct list *head;
    struct staff *people1, *people2, *people3,  *people4;

    //初始化链表
    head = list_init(NULL);//头节点不存储数据，参数为NULL

    people1 = (struct staff *)malloc(sizeof(struct staff));
    people2 = (struct staff *)malloc(sizeof(struct staff));
    people3 = (struct staff *)malloc(sizeof(struct staff));
    people4 = (struct staff *)malloc(sizeof(struct staff));

    people1->iStaffID = 1001;
    strcpy(people1->acName, "张三");
    strcpy(people1->acPasswd, "123456");

    people2->iStaffID = 1002;
    strcpy(people2->acName, "李四");
    strcpy(people2->acPasswd, "123456");

    people3->iStaffID = 1003;
    strcpy(people3->acName, "曹操");
    strcpy(people3->acPasswd, "123456");

    people4->iStaffID = 1004;
    strcpy(people4->acName, "曹植");
    strcpy(people4->acPasswd, "123456");

    //添加链表节点
    list_add(head, people1);
    list_add(head, people2);
    list_add(head, people3);
    list_add(head, people4);

    //员工信息打印函数
    list_display_generic(head, staff_printf);

    // 查找员工
    int search_id = 1009;
    struct staff *searchResult = (struct staff *)list_find_generic(head, &search_id, staff_id_find);

    staff_printf(searchResult);
    //销毁链表
    list_destroy(head, free_staff);

    return 0;
}