Linux proc檔案系統

一、頭檔案

linux/proc_fs.h

1、資料結構

struct proc_dir_entry {

unsigned int low_ino;

unsigned int namelen;

const char *name;

mode_t mode;

nlink_t nlink;

uid_t uid;

gid_t gid;

loff_t size;

const struct inode_operations *proc_iops;

const struct file_operations *proc_fops;

struct proc_dir_entry *next, *parent, *subdir;

void *data;

read_proc_t *read_proc;

write_proc_t *write_proc;

atomic_t count;

int pde_users;

spinlock_t pde_unload_lock;

struct completion *pde_unload_completion;

struct list_head pde_openers;

};

2、建立目錄

struct proc_dir_entry *proc_mkdir(const char *,struct proc_dir_entry *);

3、建立檔案

struct proc_dir_entry *create_proc_entry(const char *name, mode_t mode,

struct proc_dir_entry *parent);

4、删除目錄/檔案

void remove_proc_entry(const char *name, struct proc_dir_entry *parent);

二、源代碼檔案

1、在proc目錄下建立test目錄，并在test目錄下建立test檔案，并實作對/proc/test/test檔案進行讀寫操作

#include <linux/module.h>

#include <linux/init.h>

#include <linux/proc_fs.h>

#include <asm/uaccess.h>

static struct proc_dir_entry *test = NULL; 

static struct proc_dir_entry *proc_file = NULL;

static char msg[255];

static int 

proc_read(char *page, char **start, off_t off, int count, int *eof, void *data)

{

    int len = strlen(msg);

    if (off >= len)

        return 0;

    if (count > len - off)

        count = len - off;

    memcpy(page + off, msg + off, count);

    return (off + count);

}

static int 

proc_write(struct file *file, const char __user *buffer, unsigned long count, void *data)

{

    unsigned long count2 = count;

    if (count2 >= sizeof(msg))

        count2 = sizeof(msg) - 1;

    if (copy_from_user(msg, buffer, count2))

        return -EFAULT;

    msg[count2] = '\0';

    return count;

}

static __init proc_init(void)

{

test = proc_mkdir("test", NULL);

if (!test) {

        printk(KERN_ERR "Can't create /proc/test\n");

        return -1;

    }

proc_file = create_proc_entry("test", 0666, test);

        if (!proc_file) {

                printk(KERN_ERR "Can't create /proc/test/test\n");

                remove_proc_entry("test", NULL);// 移除test目錄

                return -1;

        }

proc_file->read_proc = proc_read;

        proc_file->write_proc = proc_write;

printk(KERN_INFO "proc_init\n");

return 0;

}

static __exit proc_exit(void)

{

remove_proc_entry("test", test); // 移除test/test

        remove_proc_entry("test", NULL); // 移除test目錄

printk(KERN_INFO "proc_exit\n");

}

module_init(proc_init);

module_exit(proc_exit);

MODULE_LICENSE("GPL");

MODULE_VERSION("v1.0");

MODULE_AUTHOR("[email protected]");

MODULE_DESCRIPTION("Proc Module");

MODULE_ALIAS("proc module");

2、Makefile

ifeq ($(KERNELRELEASE),)

KERNELDIR ?= /lib/modules/$(shell uname -r)/build

PWD := $(shell pwd)

all:                               

        $(MAKE) -C $(KERNELDIR) M=$(PWD) modules

clean:                                             

        $(MAKE) -C $(KERNELDIR) M=$(PWD) clean

else

    obj-m := proc_test.o

endif