请教一个简单的问题！

liuxuejin

本人刚咖刚学习linux的netlink！所以不太懂！

1. #ifndef __nl_h__
   
2. #define __nl_h__
   
3. #define My_netlink 17
   
4. #define U_PID 1
   
5. #define K_MSG 2
   
6. #endif
   
7. struct
   
8. {
   
9. __u32 pid;
   
10. }user_proc;

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这是头 文件
下面是 内核的模块代码

1. #include <linux/module.h>
   
2. #include <linux/init.h>
   
3. #include <linux/netlink.h>
   
4. #include <net/sock.h>
   
5. #include "nl.h"
   
6. static struct sock *nlfd;
   
7. int send_to_user(struct sock *nlfd,char *info) //发送到用户态
   
8. {
   
9. int size;
   
10. struct sk_buff *skb;
    
11. unsigned char *old_tail;
    
12. struct nlmsghdr *nlh;
    
13. size = NLMSG_SPACE(strlen(info));
    
14. skb = alloc_skb(size, GFP_ATOMIC);
    
15. nlh = NLMSG_PUT(skb, 0, 0, K_MSG, size-sizeof(*nlh));
    
16. old_tail = skb->tail;
    
17. memcpy(NLMSG_DATA(nlh) ,info,strlen(info));
    
18. nlh->nlmsg_len = skb->tail - old_tail;
    
19. netlink_unicast(nlfd, skb, user_proc.pid, MSG_DONTWAIT);
    
20. return 0;
    
21. nlmsg_failure:
    
22. if(skb)
    
23. kfree_skb(skb);
    
24. return -1;
    
25. }
    
26. void kernel_receive(struct sk_buff* __skb) //内核接受函数
    
27. {
    
28. struct sk_buff *skb;
    
29. struct nlmsghdr *nlh = NULL;
    
30. printk("begin kernel_receive\n");
    
31. skb = skb_get(__skb);
    
32. if(skb->len == sizeof(struct nlmsghdr))
    
33. {
    
34. nlh = (struct nlmsghdr *)skb->data;
    
35. if((nlh->nlmsg_len >= sizeof(struct nlmsghdr))
    
36. && (skb->len >= nlh->nlmsg_len))
    
37. {
    
38. user_proc.pid = nlh->nlmsg_pid;
    
39. printk("user_pid:%d\n",user_proc.pid);
    
40. send_to_user(nlfd,"PID send success");
    
41. }
    
42. }
    
43. else
    
44. {
    
45. printk("user data:%s\n",skb->data);
    
46. //send_to_user();
    
47. }
    
48. kfree_skb(skb);
    
49. }
    
50. int __init nl_init(void)
    
51. {
    
52. printk("nl start!!\n");
    
53. nlfd = netlink_kernel_create(&init_net, My_netlink, 0, kernel_receive, NULL, THIS_MODULE);
    
54. if(!nlfd)
    
55. {
    
56. printk("can not create a netlink socket\n");
    
57. return -1;
    
58. }
    
59. return 0;
    
60. }
    
61. void __exit nl_exit(void)
    
62. {
    
63. sock_release(nlfd->sk_socket);
    
64. printk("nl exit!!\n");
    
65. }
    
66. MODULE_AUTHOR("JZH");
    
67. MODULE_DESCRIPTION("NETLINK_TEST");
    
68. MODULE_LICENSE("GPL");
    
69. module_init(nl_init);
    
70. module_exit(nl_exit);

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这是用户程序：

1. #include <stdio.h>
   
2. #include <sys/socket.h>
   
3. #include <stdlib.h>
   
4. #include <string.h>
   
5. #include <linux/netlink.h>
   
6. #include "nl.h"
   
7. struct msg_to_kernel
   
8. {
   
9. struct nlmsghdr hdr;
   
10. };
    
11. struct u_packet_info
    
12. {
    
13. struct nlmsghdr hdr;
    
14. char msg[100];
    
15. };
    
16. int main()
    
17. {
    
18. //初始化
    
19. struct sockaddr_nl local;
    
20. struct sockaddr_nl kpeer;
    
21. int skfd,ret,kpeerlen = sizeof(struct sockaddr_nl);;
    
22. struct msg_to_kernel message;
    
23. struct u_packet_info info;
    
24. skfd = socket(PF_NETLINK, SOCK_RAW, My_netlink);
    
25. if(skfd < 0)
    
26. {
    
27. printf("can not create a netlink socket\n");
    
28. return -1;
    
29. }
    
30. memset(&local, 0, sizeof(local));
    
31. local.nl_family = AF_NETLINK;
    
32. local.nl_pid = getpid();
    
33. local.nl_groups = 0;
    
34. if(bind(skfd, (struct sockaddr*)&local, sizeof(local)) != 0)
    
35. {
    
36. printf("bind() error\n");
    
37. return -1;
    
38. }
    
39. memset(&kpeer, 0, sizeof(kpeer));
    
40. kpeer.nl_family = AF_NETLINK;
    
41. kpeer.nl_pid = 0;
    
42. kpeer.nl_groups = 0;
    
43. memset(&message, 0, sizeof(message));
    
44. message.hdr.nlmsg_len = NLMSG_LENGTH(0);
    
45. message.hdr.nlmsg_flags = 0;
    
46. message.hdr.nlmsg_type = U_PID;
    
47. message.hdr.nlmsg_pid = local.nl_pid;
    
48. //初始化结束
    
49. //发送进程PID
    
50. ret = sendto(skfd, &message, message.hdr.nlmsg_len, 0,(struct sockaddr*)&kpeer, sizeof(kpeer));
    
51. if(!ret)
    
52. {
    
53. perror("send pid:");
    
54. exit(-1);
    
55. }
    
56. //接受内核态确认信息
    
57. ret = recvfrom(skfd, &info, sizeof(struct u_packet_info),0, (struct sockaddr*)&kpeer, &kpeerlen);
    
58. if(!ret)
    
59. {
    
60. perror("recv form kerner:");
    
61. exit(-1);
    
62. }
    
63. printf("msg:%s\n",info.msg);
    
64. //内核和用户进行通信
    
65. //
    
66. close(skfd);
    
67. return 0;
    
68. }
    

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以下是Makefile:

1. obj-m := nl_k.o
   
2. all:
   
3.         make -C /usr/src/linux-headers-2.6.31-20-generic modules M=$(PWD)

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以上程序都能编译通过，但是当我执行用户程序的时候，报说 无法执行二进制文件。这是什么问题。我已经google过了。但是还没有找到问题所在！谢谢大家

xiexiecn

你的用户程序是怎么编译出来的。

liuxuejin

这个问题我已经解决了！谢谢你回帖