设备管理与模块机制.ppt

1、Linux Device ; struct file_operations loff_t (*llseek)(struct file *,loff_t,int); ssize_t (*read)(struct file *,char *,size_t,loff_t *); ssize_t (*write)(struct file *,const char *,size_t,loff_t *); int(*ioctl) (struct inode *,struct file *,unsigned int,unsigned long); int(*mmap) (struct file *,stru

2、ct vm_area_struct *); int(*open) (struct inode *,struct file *); int(*release) (struct inode *,struct file *); int(*fsync) (struct file *,struct dentry *,int datasync); int(*fasync) (int,struct file *,int); ;,Linux Device struct file_operations * fops; ; static struct device_struct chrdevsMAX_CHRDEV

3、; 注册与注销函数： int register_chrdev(unsigned int major, const char * name, struct file_operations *fops) int unregister_chrdev(unsigned int major, const char * name); 注：major即设备的主设备号，注册后就是访问数组chrdevs的索引（下标）。,字符设备的注册与管理,Linux Device struct block_device_operations *bdops; blkdevsMAX_BLKDEV;,Linux Device in

4、t (*release) (struct inode *, struct file *); int (*ioctl) (struct inode *, struct file *, unsigned, unsigned long); int (*check_media_change) (kdev_t); int (*revalidate) (kdev_t); struct module *owner; ;,Linux Device 除了open、release等函数利用了设备注册时提供的block_device_operations结构中的成员变量之外，其他函数都是采用所有块设备通用的操作函数

5、(def_blk_fops),块设备的缺省操作def_blk_fops,Linux Device ,块设备的缺省操作def_blk_fops,Linux Device queue_proc *queue; void *data; ; struct blk_dev_struct blk_devMAX_BLKDEV;,Linux Device return 0; void cleanup_module(void) printk(Goodbye cruel worldn); 编译模块 # gcc c hello.c DMODULE D_KERNEL_ -DLINUX -Wall O2 -I/usr/

6、src/linux-2.4/include 安装、卸载模块 # insmod hello.o Hello world # rmmod hello Goodbye cruel world,Linux Device & Module,模块设计注意事项,模块设计与应用程序设计 模块是装入内核的，运行时CPU处于核心态 应用程序运行时CPU处于用户态 编译模块 设计应用程序使用的include文件：/usr/include 设计内核模块使用的include文件：/usr/src/linux-2.4/include 两者如果不一致，在编译内核模块时要用-I指明include路径 设计的模块可以调用Linux内核及其他模块已经输出（exported）的函数，不能利用标准C提供的库函数如printf #more /proc/ksyms或,Linux Device & Module,模块调试,printk 利用/proc文件系统或ioctl； ksy