#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/version.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <asm/uaccess.h>
static unsigned int variable;
static struct proc_dir_entry *test_dir, *test_entry;
#if LINUX_VERSION_CODE < KERNEL_VERSION(3, 10, 0)
static int test_proc_read(char *buf, char **start, off_t off, int count,
int *eof, void *data)
{
unsigned int *ptr_var = data;
return sprintf(buf, "test_rw = %u\n", *ptr_var);
}
static int test_proc_write(struct file *file, const char *buffer,
unsigned long count, void *data)
{
unsigned int *ptr_var = data;
*ptr_var = simple_strtoul(buffer, NULL, 10);
return count;
}
#else
static int test_proc_show(struct seq_file *seq, void *v)
{
unsigned int *ptr_var = seq->private;
seq_printf(seq, "%u\n", *ptr_var);
return 0;
}
static ssize_t test_proc_write(struct file *file, const char __user *buffer,
size_t count, loff_t *ppos)
{
struct seq_file *seq = file->private_data;
unsigned int *ptr_var = seq->private;
int err;
char *kbuffer;
if (!buffer || count > PAGE_SIZE - 1)
return -EINVAL;
kbuffer = (char *)__get_free_page(GFP_KERNEL);
if (!kbuffer)
return -ENOMEM;
err = -EFAULT;
if (copy_from_user(kbuffer, buffer, count))
goto out;
kbuffer[count] = '\0';
*ptr_var = simple_strtoul(kbuffer, NULL, 10);
return count;
out:
free_page((unsigned long)buffer);
return err;
}
static int test_proc_open(struct inode *inode, struct file *file)
{
return single_open(file, test_proc_show, PDE_DATA(inode));
}
static const struct file_operations test_proc_fops =
{
.owner = THIS_MODULE,
.open = test_proc_open,
.read = seq_read,
.write = test_proc_write,
.llseek = seq_lseek,
.release = single_release,
};
#endif
static __init int test_proc_init(void)
{
test_dir = proc_mkdir("test_dir", NULL);
if (test_dir) {
#if LINUX_VERSION_CODE < KERNEL_VERSION(3, 10, 0)
test_entry = create_proc_entry("test_rw", 0666, test_dir);
if (test_entry) {
test_entry->nlink = 1;
test_entry->data = &variable;
test_entry->read_proc = test_proc_read;
test_entry->write_proc = test_proc_write;
return 0;
}
#else
test_entry = proc_create_data("test_rw",0666, test_dir, &test_proc_fops, &variable);
if (test_entry)
return 0;
#endif
}
return -ENOMEM;
}
module_init(test_proc_init);
static __exit void test_proc_cleanup(void)
{
remove_proc_entry("test_rw", test_dir);
remove_proc_entry("test_dir", NULL);
}
module_exit(test_proc_cleanup);
MODULE_AUTHOR("Barry Song <[email protected]>");
MODULE_DESCRIPTION("proc exmaple");
MODULE_LICENSE("GPL v2");
variable是全局变量,如何在proc操作间传递?
static unsigned int variable;
static __init int test_proc_init(void)
test_entry = proc_create_data("test_rw",0666, test_dir, &test_proc_fops, &variable);
pde = __proc_create(&parent, name, mode, 1);
pde->proc_fops = proc_fops;
pde->data = data;
proc_register(parent, pde)
return pde;
所以
test_entry->date == &variable
根据
static const struct file_operations test_proc_fops =
{
...
.open = test_proc_open,
...
};
static int test_proc_open(struct inode *inode, struct file *file)
single_open(file, test_proc_show, PDE_DATA(inode));
res = seq_open(file, op);
((struct seq_file *)file->private_data)->private = data;
首先整理PDE_DATA是什么
struct proc_inode {
struct pid *pid;
int fd;
union proc_op op;
struct proc_dir_entry *pde;
struct ctl_table_header *sysctl;
struct ctl_table *sysctl_entry;
struct proc_ns ns;
struct inode vfs_inode;
};
/*
* General functions
*/
static inline struct proc_inode *PROC_I(const struct inode *inode)
{
return container_of(inode, struct proc_inode, vfs_inode);
}
static inline struct proc_dir_entry *PDE(const struct inode *inode)
{
return PROC_I(inode)->pde;
}
data 即是 PDE_DATA(inode) 即是
container_of(inode, struct proc_inode, vfs_inode)->pde;
即
proc_inode->pde;
即
struct proc_dir_entry *pde;
PDE_DATA(inode)即是test_rw
struct proc_dir_entry *proc_create_data(const char *name, umode_t mode,
struct proc_dir_entry *parent,
const struct file_operations *proc_fops, void *data)
{
struct proc_dir_entry *p;
BUG_ON(proc_fops == NULL);
p = proc_create_reg(name, mode, &parent, data);
if (!p)
return NULL;
p->proc_fops = proc_fops;
return proc_register(parent, p);
}
EXPORT_SYMBOL(proc_create_data);