proc fs 例子

static ssize_t write_sysrq_trigger(struct file *file, const char __user *buf,   size_t count, loff_t *ppos){if (count) {char c;if (get_user(c, buf))return -EFAULT;__handle_sysrq(c, NULL, 0);}return count;}static const struct file_operations proc_sysrq_trigger_operations = {.write= write_sysrq_trigger,};static void sysrq_init_procfs(void){if (!proc_create("sysrq-trigger", S_IWUSR, NULL, &proc_sysrq_trigger_operations))pr_err("Failed to register proc interface\n");}

会生成 ：  /proc/sysrq-trigger 由于user与kernel通讯