[RFC][PATCH] Inotify kernel API

[Amy Griffis]

I'm attaching a small demonstration module that uses the Inotify
kernel API from my patch, in case anyone is interested.

It takes a watch path (file or directory) as a parameter on init:

    # insmod imod.ko watch_path=/tmp/foo

This is just a simple client, so the file/directory must exist. :-)

Regards,
Amy
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#include <linux/module.h>
#include <linux/init.h>
#include <linux/moduleparam.h>
#include <linux/inotify.h>
#include <linux/namei.h>

static char *watch_path = "";
module_param(watch_path, charp, 0);

static struct inotify_device *dev;
static s32 wd;
static char *mylist[] = { "bike", "hack", "eat", "sleep", "rinse", "repeat" };

static void handle_inotify_event(struct inotify_event *event, const char *path,
				 void *arg)
{
	char *myactivity = arg;

	printk(KERN_DEBUG 
	       "imod: wd=%08x, mask=%08x, cookie=%x, path=\"%s\", arg=\"%s\"\n",
	       event->wd, event->mask, event->cookie, path ?: "(null)",
	       myactivity);
}

static int __init imod_init(void)
{
	struct nameidata nd;
	int retval;

	if (*watch_path == '\0') {
		printk(KERN_DEBUG "imod: watch_path must be specified\n");
		return -EINVAL;
	}

	retval = path_lookup(watch_path, 0, &nd);
	if (retval) {
		printk(KERN_DEBUG "imod: path_lookup returned %d\n", retval);
		return retval;
	}

	dev = inotify_init(handle_inotify_event);
	if (!dev) {
		printk(KERN_DEBUG "imod: inotify_init failed\n");
		return -ENOMEM;
	}

	wd = inotify_add_watch(dev, nd.dentry->d_inode, IN_ALL_EVENTS, 
			       mylist[1]);
	if (wd < 0) {
		printk(KERN_DEBUG "imod: inotify_add_watch returned %d\n", wd);
		return wd;
	}

	return 0;
}

static void __exit imod_cleanup(void)
{
	inotify_free(dev);
}

module_init(imod_init);
module_exit(imod_cleanup);
MODULE_LICENSE("GPL");

/* vim:set noet sw=8: */