简单驱动出错

haohao_h

我加入一个file_operations结构后就出现unknown field 'read' specified in initializer错误，没搞明白！

1. #ifndef __KERNEL__
   
2. #define __KERNEL__
   
3. #endif
   
4. #ifndef MODULE
   
5. #define MODULE
   
6. #endif
   
7. 
   
8. #define __NO_VERSION__
   
9. 
   
10. #include <linux/config.h>
    
11. #include <linux/module.h>
    
12. 
    
13. MODULE_LICENSE("GPL");
    
14. #ifdef CONFIG_SMP
    
15. #define __SMP__
    
16. #endif
    
17. 
    
18. #include <linux/kernel.h> /* printk()*/
    
19. #include <linux/fs.h>/*file_operations*/
    
20. 
    
21. static ssize_t hello_read();
    
22. static ssize_t hello_write();
    
23. static int hello_open();
    
24. static int hello_release();
    
25. 
    
26. struct file_operations hello_fops={
    
27. read: hello_read,};
    
28. /*上面这行出现unknown field 'read' specified in initializer错误，是什么原因？*/
    
29. ///////////////////////////////////////////////////////////////////////////////////////
    
30. /////////////////////////////////////////////////////////////////////////////////////////
    
31. static ssize_t hello_read(struct file *filp,char *buf, size_t len, loff_t *ppos)
    
32. {
    
33.         return 0;
    
34. }
    
35. 
    
36. static ssize_t hello_write(struct file *filp,char *buf, size_t len,loff_t *ppos){
    
37.         return 0;
    
38. }
    
39. 
    
40. static int hello_open(struct inode *inode,struct file *filp ){
    
41.         //MOD_INC_USE_COUNT;
    
42.         return 0;
    
43. }
    
44. 
    
45. static int hello_release( struct inode *inode,struct file *filp){
    
46.         //MOD_DEC_USE_COUNT;
    
47.         return 0;
    
48. }
    
49. 
    
50. int init_module(void){
    
51.         printk("Hello,World!\n");
    
52.         return 0; /* 如果初始工作失败，就返回非0 */
    
53. }
    
54. 
    
55. static void exit_module(void){
    
56.         printk("Bye!\n");
    
57. }
    

复制代码

Tetris

注意include目录是/usr/src/linux/include，不是/usr/include

haohao_h

这个应该没错，内核版本是2.4.20-8，Makefile文件如下

1. OBJS = hello.o
   
2. CFLAG =
   
3. CC = gcc
   
4. KERNELDIR = /usr/src/linux2.4.20-8
   
5. #include $(KERNELDIR)/.config
   
6. 
   
7. all:$(OBJS)
   
8. hello.o:hello.c
   
9.         gcc -D__KERNEL__ -D_MOUDLE -I$(KERNELDIR)/include -c $^ -o $@
   
10. clean:
    
11.         rm -f $(OBJS)
    

复制代码

gotop2004

你把static 去了看看

haohao_h

一样的！

Tetris

到头文件里看看file_operations的定义有没有问题。这个太诡异了

nuclearweapon

改成这样看看

struct file_operations hello_fops={
.read＝ hello_read};

haohao_h

这个是c99语法，据说具有更好的兼容性，我试了，还是不行！很奇怪，我把struct file_operations hello_fops={
read: hello_read,};
改成struct file_operations *hello_fops=NULL;就不出错了，在/usr/include目录下的fs.h文件没有file_operations结构的定义，说明我的include目录应该是正确的吧！file_operations结构我看不出有什么问题

1. 
   
2. /*
   
3. * NOTE:
   
4. * read, write, poll, fsync, readv, writev can be called
   
5. *   without the big kernel lock held in all filesystems.
   
6. */
   
7. struct file_operations {
   
8.         struct module *owner;
   
9.         loff_t (*llseek) (struct file *, loff_t, int);
   
10.         ssize_t (*read) (struct file *, char *, size_t, loff_t *);
    
11.         ssize_t (*write) (struct file *, const char *, size_t, loff_t *);
    
12.         int (*readdir) (struct file *, void *, filldir_t);
    
13.         unsigned int (*poll) (struct file *, struct poll_table_struct *);
    
14.         int (*ioctl) (struct inode *, struct file *, unsigned int, unsigned long);
    
15.         int (*mmap) (struct file *, struct vm_area_struct *);
    
16.         int (*open) (struct inode *, struct file *);
    
17.         int (*flush) (struct file *);
    
18.         int (*release) (struct inode *, struct file *);
    
19.         int (*fsync) (struct file *, struct dentry *, int datasync);
    
20.         int (*fasync) (int, struct file *, int);
    
21.         int (*lock) (struct file *, int, struct file_lock *);
    
22.         ssize_t (*readv) (struct file *, const struct iovec *, unsigned long, loff_t *);
    
23.         ssize_t (*writev) (struct file *, const struct iovec *, unsigned long, loff_t *);
    
24.         ssize_t (*sendpage) (struct file *, struct page *, int, size_t, loff_t *, int);
    
25.         unsigned long (*get_unmapped_area)(struct file *, unsigned long, unsigned long, unsigned long, unsigned long);
    
26. };
    

复制代码

haohao_h

我把struct file_operations hello_fops={
read: hello_read,};改成struct file_operations *hello_fops={NULL,NULL,hello_read,NULL};之后编译通过，不知道是不是我GCC版本的原因，我的GCC是3.2.2？真是什么也不懂啊！
又出现了新问题，编译通过用insmod hello.o加载模块，显示“hello，world!”应该加载成功喽？可是我的/proc/device文件下并没有出现相应的设备名hello和设备号37，这又是什么原因呢？

1. #ifndef __KERNEL__
   
2. #define __KERNEL__
   
3. #endif
   
4. #ifndef MODULE
   
5. #define MODULE
   
6. #endif
   
7. 
   
8. #define __NO_VERSION__
   
9. 
   
10. #include <linux/config.h>
    
11. #include <linux/module.h>
    
12. 
    
13. MODULE_LICENSE("GPL");
    
14. #ifdef CONFIG_SMP
    
15. #define __SMP__
    
16. #endif
    
17. 
    
18. #include <linux/kernel.h> /* printk()*/
    
19. #include <linux/fs.h>/*file_operations*/
    
20. #include <linux/init.h>/*moudle_init moudle_exit*/
    
21. //#include <asm/uaccess.h>/**/
    
22. 
    
23. 
    
24. #define MAJOR_ID 37
    
25. 
    
26. 
    
27. static ssize_t hello_read();
    
28. static ssize_t hello_write();
    
29. static int hello_open();
    
30. static int hello_release();
    
31. 
    
32. struct file_operations *hello_fops={NULL,NULL,hello_read,hello_write,NULL};
    
33. 
    
34. static ssize_t hello_read(struct file *filp,char *buf, size_t len, loff_t *ppos)
    
35. {
    
36.         printk("Hello,read!\n");
    
37.         return 0;
    
38. }
    
39. 
    
40. static ssize_t hello_write(struct file *filp,char *buf, size_t len,loff_t *ppos){
    
41.         printk("Hello,write!\n");
    
42.         return 0;
    
43. }
    
44. 
    
45. static int hello_open(struct inode *inode,struct file *filp ){
    
46.         //MOD_INC_USE_COUNT;
    
47.         return 0;
    
48. }
    
49. 
    
50. static int hello_release( struct inode *inode,struct file *filp){
    
51.         //MOD_DEC_USE_COUNT;
    
52.         return 0;
    
53. }
    
54. 
    
55. int __init hello_init(void){
    
56. 
    
57.         int result;                
    
58.         result=register_chrdev(MAJOR_ID,"hello",hello_fops);
    
59.         if(result<0){
    
60.                 printk("CAN NOT GET MAJOR!");
    
61.         }       
    
62.         printk("Hello,World!\n");       
    
63.         return 0;
    
64. }
    
65. 
    
66. static void __exit hello_exit(void){
    
67.         unregister_chrdev(MAJOR_ID,"hello");
    
68.         printk("Bye!\n");
    
69. }
    
70. 
    
71. module_init(hello_init);
    
72. module_exit(hello_exit);

复制代码

Tetris

看/proc/modules
你的gcc有点老。