Setting ->owner as done currently (pde->owner = THIS_MODULE) is racy as correctly noted at bug #12454. Someone can lookup entry with NULL ->owner, thus not pinning enything, and release it later resulting in module refcount underflow. We can keep ->owner and supply it at registration time like ->proc_fops and ->data. But this leaves ->owner as easy-manipulative field (just one C assignment) and somebody will forget to unpin previous/pin current module when switching ->owner. ->proc_fops is declared as "const" which should give some thoughts. ->read_proc/->write_proc were just fixed to not require ->owner for protection. rmmod'ed directories will be empty and return "." and ".." -- no harm. And directories with tricky enough readdir and lookup shouldn't be modular. We definitely don't want such modular code. Removing ->owner will also make PDE smaller. So, let's nuke it. Kudos to Jeff Layton for reminding about this, let's say, oversight. http://bugzilla.kernel.org/show_bug.cgi?id=12454 Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
		
			
				
	
	
		
			117 lines
		
	
	
		
			2.8 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			117 lines
		
	
	
		
			2.8 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
| /*
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|  * RTC subsystem, proc interface
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|  *
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|  * Copyright (C) 2005-06 Tower Technologies
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|  * Author: Alessandro Zummo <a.zummo@towertech.it>
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|  *
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|  * based on arch/arm/common/rtctime.c
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|  *
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|  * This program is free software; you can redistribute it and/or modify
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|  * it under the terms of the GNU General Public License version 2 as
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|  * published by the Free Software Foundation.
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| */
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| 
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| #include <linux/module.h>
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| #include <linux/rtc.h>
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| #include <linux/proc_fs.h>
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| #include <linux/seq_file.h>
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| 
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| #include "rtc-core.h"
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| 
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| 
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| static int rtc_proc_show(struct seq_file *seq, void *offset)
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| {
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| 	int err;
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| 	struct rtc_device *rtc = seq->private;
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| 	const struct rtc_class_ops *ops = rtc->ops;
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| 	struct rtc_wkalrm alrm;
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| 	struct rtc_time tm;
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| 
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| 	err = rtc_read_time(rtc, &tm);
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| 	if (err == 0) {
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| 		seq_printf(seq,
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| 			"rtc_time\t: %02d:%02d:%02d\n"
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| 			"rtc_date\t: %04d-%02d-%02d\n",
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| 			tm.tm_hour, tm.tm_min, tm.tm_sec,
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| 			tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday);
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| 	}
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| 
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| 	err = rtc_read_alarm(rtc, &alrm);
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| 	if (err == 0) {
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| 		seq_printf(seq, "alrm_time\t: ");
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| 		if ((unsigned int)alrm.time.tm_hour <= 24)
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| 			seq_printf(seq, "%02d:", alrm.time.tm_hour);
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| 		else
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| 			seq_printf(seq, "**:");
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| 		if ((unsigned int)alrm.time.tm_min <= 59)
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| 			seq_printf(seq, "%02d:", alrm.time.tm_min);
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| 		else
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| 			seq_printf(seq, "**:");
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| 		if ((unsigned int)alrm.time.tm_sec <= 59)
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| 			seq_printf(seq, "%02d\n", alrm.time.tm_sec);
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| 		else
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| 			seq_printf(seq, "**\n");
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| 
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| 		seq_printf(seq, "alrm_date\t: ");
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| 		if ((unsigned int)alrm.time.tm_year <= 200)
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| 			seq_printf(seq, "%04d-", alrm.time.tm_year + 1900);
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| 		else
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| 			seq_printf(seq, "****-");
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| 		if ((unsigned int)alrm.time.tm_mon <= 11)
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| 			seq_printf(seq, "%02d-", alrm.time.tm_mon + 1);
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| 		else
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| 			seq_printf(seq, "**-");
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| 		if (alrm.time.tm_mday && (unsigned int)alrm.time.tm_mday <= 31)
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| 			seq_printf(seq, "%02d\n", alrm.time.tm_mday);
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| 		else
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| 			seq_printf(seq, "**\n");
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| 		seq_printf(seq, "alarm_IRQ\t: %s\n",
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| 				alrm.enabled ? "yes" : "no");
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| 		seq_printf(seq, "alrm_pending\t: %s\n",
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| 				alrm.pending ? "yes" : "no");
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| 	}
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| 
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| 	seq_printf(seq, "24hr\t\t: yes\n");
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| 
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| 	if (ops->proc)
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| 		ops->proc(rtc->dev.parent, seq);
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| 
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| 	return 0;
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| }
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| 
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| static int rtc_proc_open(struct inode *inode, struct file *file)
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| {
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| 	struct rtc_device *rtc = PDE(inode)->data;
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| 
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| 	if (!try_module_get(THIS_MODULE))
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| 		return -ENODEV;
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| 
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| 	return single_open(file, rtc_proc_show, rtc);
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| }
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| 
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| static int rtc_proc_release(struct inode *inode, struct file *file)
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| {
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| 	int res = single_release(inode, file);
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| 	module_put(THIS_MODULE);
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| 	return res;
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| }
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| 
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| static const struct file_operations rtc_proc_fops = {
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| 	.open		= rtc_proc_open,
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| 	.read		= seq_read,
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| 	.llseek		= seq_lseek,
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| 	.release	= rtc_proc_release,
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| };
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| 
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| void rtc_proc_add_device(struct rtc_device *rtc)
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| {
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| 	if (rtc->id == 0)
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| 		proc_create_data("driver/rtc", 0, NULL, &rtc_proc_fops, rtc);
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| }
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| 
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| void rtc_proc_del_device(struct rtc_device *rtc)
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| {
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| 	if (rtc->id == 0)
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| 		remove_proc_entry("driver/rtc", NULL);
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| }
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