nhmk/examples/procfs1.c
Jim Huang faf3aa7c22 Make each source file more consistent
It is vital to denote the file name and summary for each source,
otherwise readers could not figure out the corresponding files.
2021-07-22 11:25:32 +08:00

64 lines
1.4 KiB
C

/*
* procfs1.c
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/proc_fs.h>
#include <linux/uaccess.h>
#include <linux/version.h>
#if LINUX_VERSION_CODE >= KERNEL_VERSION(5, 6, 0)
#define HAVE_PROC_OPS
#endif
#define procfs_name "helloworld"
struct proc_dir_entry *Our_Proc_File;
ssize_t procfile_read(struct file *filePointer,
char *buffer,
size_t buffer_length,
loff_t *offset)
{
int ret = 0;
if (strlen(buffer) == 0) {
pr_info("procfile read %s\n", filePointer->f_path.dentry->d_name.name);
ret = copy_to_user(buffer, "HelloWorld!\n", sizeof("HelloWorld!\n"));
ret = sizeof("HelloWorld!\n");
}
return ret;
}
#ifdef HAVE_PROC_OPS
static const struct proc_ops proc_file_fops = {
.proc_read = procfile_read,
};
#else
static const struct file_operations proc_file_fops = {
.read = procfile_read,
};
#endif
int init_module()
{
Our_Proc_File = proc_create(procfs_name, 0644, NULL, &proc_file_fops);
if (NULL == Our_Proc_File) {
proc_remove(Our_Proc_File);
pr_alert("Error:Could not initialize /proc/%s\n", procfs_name);
return -ENOMEM;
}
pr_info("/proc/%s created\n", procfs_name);
return 0;
}
void cleanup_module()
{
proc_remove(Our_Proc_File);
pr_info("/proc/%s removed\n", procfs_name);
}
MODULE_LICENSE("GPL");