Linux 驱动开发 -proc 接口介绍

#include <stdio.h>#include <stdlib.h>#include <unistd.h>
typedef struct cpu_occupy_          //定义一个cpu occupy的结构体{    char name[20];                  //定义一个char类型的数组名name有20个元素    unsigned int user;              //定义一个无符号的int类型的user    unsigned int nice;              //定义一个无符号的int类型的nice    unsigned int system;            //定义一个无符号的int类型的system    unsigned int idle;              //定义一个无符号的int类型的idle    unsigned int iowait;    unsigned int irq;    unsigned int softirq;}cpu_occupy_t;
double cal_cpuoccupy (cpu_occupy_t *o, cpu_occupy_t *n){    double od, nd;    double id, sd;    double cpu_use ;
    od = (double) (o->user + o->nice + o->system +o->idle+o->softirq+o->iowait+o->irq);//第一次(用户+优先级+系统+空闲)的时间再赋给od    nd = (double) (n->user + n->nice + n->system +n->idle+n->softirq+n->iowait+n->irq);//第二次(用户+优先级+系统+空闲)的时间再赋给od
    id = (double) (n->idle);    //用户第一次和第二次的时间之差再赋给id    sd = (double) (o->idle) ;    //系统第一次和第二次的时间之差再赋给sd    if((nd-od) != 0)        cpu_use =100.0 - ((id-sd))/(nd-od)*100.00; //((用户+系统)乖100)除(第一次和第二次的时间差)再赋给g_cpu_used    else         cpu_use = 0;    return cpu_use;}
void get_cpuoccupy (cpu_occupy_t *cpust){    FILE *fd;    int n;    char buff[256];    cpu_occupy_t *cpu_occupy;    cpu_occupy=cpust;
    fd = fopen ("/proc/stat", "r");    if(fd == NULL)    {            perror("fopen:");            exit (0);    }    fgets (buff, sizeof(buff), fd);
    sscanf (buff, "%s %u %u %u %u %u %u %u", cpu_occupy->name, &cpu_occupy->user, &cpu_occupy->nice,&cpu_occupy->system, &cpu_occupy->idle ,&cpu_occupy->iowait,&cpu_occupy->irq,&cpu_occupy->softirq);
    fclose(fd);}
double get_sysCpuUsage(){    cpu_occupy_t cpu_stat1;    cpu_occupy_t cpu_stat2;    double cpu;    get_cpuoccupy((cpu_occupy_t *)&cpu_stat1);    sleep(1);    //第二次获取cpu使用情况    get_cpuoccupy((cpu_occupy_t *)&cpu_stat2);
    //计算cpu使用率    cpu = cal_cpuoccupy ((cpu_occupy_t *)&cpu_stat1, (cpu_occupy_t *)&cpu_stat2);
    return cpu;}
int main(int argc,char **argv){    while(1)    {        printf("CPU占用率:%f\n",get_sysCpuUsage());    }    return 0;}

#include <linux/proc_fs.h>#include <linux/fs.h>

1.  在proc目录下创建子目录函数static inline struct proc_dir_entry *proc_mkdir(const char *name,struct proc_dir_entry *parent)示例: //注意只能创建单层目录//在proc目录下创建aaa文件夹proc_mkdir("aaa",NULL);
2.  在proc目录下创建文件static inline struct proc_dir_entry *proc_create(const char *name,    //文件名称umode_t mode,      //模式，默认为0struct proc_dir_entry *parent,   //父目录结构const struct file_operations *proc_fops)  //文件集合示例://在proc目录下创建一个文件proc_create("aaa/tiny4412_proc_test", 0, NULL, &fops_proc);
3.  删除proc目录下之前创建的文件或者目录void remove_proc_entry(const char *name,   //文件的路径struct proc_dir_entry *parent  //父目录结构)示例:remove_proc_entry("aaa/tiny4412_proc_test", NULL);注意: 如果是删除目录，需要先把目录下的文件删除掉，每次删除必须保证目录是空的。

#include <linux/kernel.h>#include <linux/module.h>#include <linux/miscdevice.h>#include <linux/fs.h>#include <asm/uaccess.h>#include <asm/io.h>#include <linux/delay.h>#include <linux/gpio.h>#include <mach/gpio.h>#include <plat/gpio-cfg.h>#include <linux/proc_fs.h>
static int tiny4412_open(struct inode *inode, struct file *file){       printk("tiny4412_open ok\n");    return 0;}
static ssize_t tiny4412_read(struct file *file, char __user *buf, size_t cnt, loff_t *loff){    copy_to_user(buf,"123456",6);    printk("tiny4412_read调用成功.\n");    return 0;}
static int tiny4412_release(struct inode *inode, struct file *file){    return 0;}
static struct file_operations tiny4412_fops={    .open=tiny4412_open,    .read=tiny4412_read,    .release=tiny4412_release,};
static int __init tiny4412_init(void){    proc_mkdir("wbyq",0);    /*创建内核接口: proc  存放内核信息*/    proc_create("wbyq/tiny4412_proc",0, NULL, &tiny4412_fops);        printk("驱动安装成功.\n");    return 0;}
static void __exit tiny4412_exit(void){    remove_proc_entry("wbyq/tiny4412_proc", NULL);    remove_proc_entry("wbyq", NULL);    printk("驱动卸载成功.\n");}
/*驱动的入口:insmod xxx.ko*/module_init(tiny4412_init);/*驱动的出口: rmmod xxx.ko*/module_exit(tiny4412_exit);/*模块的许可证*/MODULE_LICENSE("GPL");/*模块的作者*/MODULE_AUTHOR("wbyq");

#include <linux/kernel.h> #include <linux/module.h>#include <linux/miscdevice.h>#include <linux/fs.h>#include <linux/io.h>#include <asm/uaccess.h>#include <linux/gpio.h>#include <mach/gpio.h>#include <plat/gpio-cfg.h>#include <linux/device.h>#include <linux/mutex.h>#include <linux/list.h>#include <linux/proc_fs.h>static struct class *tiny4412_beep_class;static unsigned int major=0; //主设备号
static LIST_HEAD(tiny4412_beep_list);   //链表头static DEFINE_MUTEX(tiny4412_beep_mtx); //互斥锁
#define DYNAMIC_MINORS 64 /* like dynamic majors */static DECLARE_BITMAP(beep_minors, DYNAMIC_MINORS);
struct tiny4412_beep_device{    int minor;   /*次设备号*/    const char *name; /*设备节点的名称*/    const struct file_operations *fops; /*文件操作集合*/    struct list_head list; //链表};
int tiny4412_beep_register(struct tiny4412_beep_device *beep_dev){    struct tiny4412_beep_device *c;    dev_t dev;        INIT_LIST_HEAD(&beep_dev->list);        mutex_lock(&tiny4412_beep_mtx);
    //查找传入的次设备号是否冲突    list_for_each_entry(c, &tiny4412_beep_list, list)    {        if(c->minor == beep_dev->minor)        {            mutex_unlock(&tiny4412_beep_mtx);            return -EBUSY;        }    }        //自动分配    if(beep_dev->minor == MISC_DYNAMIC_MINOR)     {        int i = find_first_zero_bit(beep_minors,DYNAMIC_MINORS);        if (i >= DYNAMIC_MINORS)        {            mutex_unlock(&tiny4412_beep_mtx);            return -EBUSY;        }        beep_dev->minor = DYNAMIC_MINORS - i - 1;        set_bit(i,beep_minors);    }
    //合成设备号    dev = MKDEV(major, beep_dev->minor);
    //创建设备节点    device_create(tiny4412_beep_class,NULL,dev,NULL,"%s", beep_dev->name);        list_add(&beep_dev->list,&tiny4412_beep_list);        //解锁    mutex_unlock(&tiny4412_beep_mtx);    return 0;}
int tiny4412_beep_deregister(struct tiny4412_beep_device *beep_dev){    int i = DYNAMIC_MINORS - beep_dev->minor - 1;
    mutex_lock(&tiny4412_beep_mtx);    list_del(&beep_dev->list);
    //将dev目录下的文件删除掉    device_destroy(tiny4412_beep_class, MKDEV(major, beep_dev->minor));    if (i < DYNAMIC_MINORS && i >= 0)        clear_bit(i, beep_minors);    mutex_unlock(&tiny4412_beep_mtx);    return 0;}
EXPORT_SYMBOL_GPL(tiny4412_beep_register); EXPORT_SYMBOL_GPL(tiny4412_beep_deregister); 
//底层open函数static int tiny4412_beep_open(struct inode * inode, struct file * file){    //得到次设备号    int minor = iminor(inode);        struct tiny4412_beep_device *c;    struct file_operations *new_fops,*old_fops;    mutex_lock(&tiny4412_beep_mtx);    //遍历链表--找到链表里相同的次设备号    list_for_each_entry(c,&tiny4412_beep_list, list)     {        if (c->minor == minor)        {            new_fops = fops_get(c->fops);    //得到47次设备号对应的结构体地址             break;        }    }    file->f_op = new_fops; //改变指向--文件操作集合的指向    if(file->f_op->open)    {        file->f_op->open(inode,file);    }    fops_put(old_fops);    mutex_unlock(&tiny4412_beep_mtx);    return 0;}
static const struct file_operations tiny4412_beep_fops ={    .owner      = THIS_MODULE,    .open       = tiny4412_beep_open,};
static ssize_t tiny4412_read(struct file *file, char __user *buf, size_t cnt, loff_t *loff){    struct tiny4412_beep_device *c;    //遍历链表--找到链表里相同的次设备号    list_for_each_entry(c,&tiny4412_beep_list, list)     {        printk("%d %s\n",c->minor,c->name);    }    return 0;}
static struct file_operations tiny4412_fops={    .read=tiny4412_read,};
static int __init tiny4412_beep_class_init(void){    /*1. 创建设备类*/    tiny4412_beep_class=class_create(THIS_MODULE,"tiny4412_beep");    /*2. 注册字符设备*/    major=register_chrdev(0,"tiny4412_beep",&tiny4412_beep_fops);        proc_mkdir("wbyq",0);    /*创建内核接口: proc  存放内核信息*/    proc_create("wbyq/tiny4412_proc",0, NULL, &tiny4412_fops);        return 0;}
static void __exit tiny4412_beep_class_cleanup(void){    remove_proc_entry("wbyq/tiny4412_proc", NULL);    remove_proc_entry("wbyq", NULL);        //注销设备类    class_destroy(tiny4412_beep_class);    //注销字符设备    unregister_chrdev(major,"tiny4412_beep");}
module_init(tiny4412_beep_class_init);module_exit(tiny4412_beep_class_cleanup);
MODULE_LICENSE("GPL");MODULE_AUTHOR("wbyq");