/*
 * The USB Monitor, inspired by Dave Harding's USBMon.
 *
 * This is the 's' or 'stat' reader which debugs usbmon itself.
 * Note that this code blows through locks, so make sure that
 * /dbg/usbmon/0s is well protected from non-root users.
 *
 */

#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/export.h>
#include <linux/usb.h>
#include <linux/fs.h>
#include <linux/uaccess.h>

#include "usb_mon.h"

#define STAT_BUF_SIZE  80

struct snap {
	int slen;
	char str[STAT_BUF_SIZE];
};

static int mon_stat_open(struct inode *inode, struct file *file)
{
	struct mon_bus *mbus;
	struct snap *sp;

	sp = kmalloc(sizeof(struct snap), GFP_KERNEL);
	if (sp == NULL)
		return -ENOMEM;

	mbus = inode->i_private;

	sp->slen = snprintf(sp->str, STAT_BUF_SIZE,
	    "nreaders %d events %u text_lost %u\n",
	    mbus->nreaders, mbus->cnt_events, mbus->cnt_text_lost);

	file->private_data = sp;
	return 0;
}

static ssize_t mon_stat_read(struct file *file, char __user *buf,
				size_t nbytes, loff_t *ppos)
{
	struct snap *sp = file->private_data;

	return simple_read_from_buffer(buf, nbytes, ppos, sp->str, sp->slen);
}

static int mon_stat_release(struct inode *inode, struct file *file)
{
	struct snap *sp = file->private_data;
	file->private_data = NULL;
	kfree(sp);
	return 0;
}

const struct file_operations mon_fops_stat = {
	.owner =	THIS_MODULE,
	.open =		mon_stat_open,
	.llseek =	no_llseek,
	.read =		mon_stat_read,
	/* .write =	mon_stat_write, */
	/* .poll =		mon_stat_poll, */
	/* .unlocked_ioctl =	mon_stat_ioctl, */
	.release =	mon_stat_release,
};
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<div class='path'>path: <a href='/cgit.cgi/linux/net-next.git/commit/?id=69973b830859bc6529a7a0468ba0d80ee5117826'>root</a>/<a href='/cgit.cgi/linux/net-next.git/commit/net?id=69973b830859bc6529a7a0468ba0d80ee5117826'>net</a>/<a href='/cgit.cgi/linux/net-next.git/commit/net/irda?id=69973b830859bc6529a7a0468ba0d80ee5117826'>irda</a>/<a href='/cgit.cgi/linux/net-next.git/commit/net/irda/irnet?id=69973b830859bc6529a7a0468ba0d80ee5117826'>irnet</a>/<a href='/cgit.cgi/linux/net-next.git/commit/net/irda/irnet/Makefile?id=69973b830859bc6529a7a0468ba0d80ee5117826'>Makefile</a></div><div class='content'><div class='cgit-panel'><b>diff options</b><form method='get'><input type='hidden' name='id' value='69973b830859bc6529a7a0468ba0d80ee5117826'/><table><tr><td colspan='2'/></tr><tr><td class='label'>context:</td><td class='ctrl'><select name='context' onchange='this.form.submit();'><option value='1'>1</option><option value='2'>2</option><option value='3' selected='selected'>3</option><option value='4'>4</option><option value='5'>5</option><option value='6'>6</option><option value='7'>7</option><option value='8'>8</option><option value='9'>9</option><option value='10'>10</option><option value='15'>15</option><option value='20'>20</option><option value='25'>25</option><option value='30'>30</option><option value='35'>35</option><option value='40'>40</option></select></td></tr><tr><td class='label'>space:</td><td class='ctrl'><select name='ignorews' onchange='this.form.submit();'><option value='0' selected='selected'>include</option><option value='1'>ignore</option></select></td></tr><tr><td class='label'>mode:</td><td class='ctrl'><select name='dt' onchange='this.form.submit();'><option value='0' selected='selected'>unified</option><option value='1'>ssdiff</option><option value='2'>stat only</option></select></td></tr><tr><td/><td class='ctrl'><noscript><input type='submit' value='reload'/></noscript></td></tr></table></form></div><table summary='commit info' class='commit-info'>
<tr><th>author</th><td>Linus Torvalds &lt;torvalds@linux-foundation.org&gt;</td><td class='right'>2016-12-11 11:17:54 -0800</td></tr>
<tr><th>committer</th><td>Linus Torvalds &lt;torvalds@linux-foundation.org&gt;</td><td class='right'>2016-12-11 11:17:54 -0800</td></tr>
<tr><th>commit</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/net/irda/irnet/Makefile?id=69973b830859bc6529a7a0468ba0d80ee5117826'>69973b830859bc6529a7a0468ba0d80ee5117826</a> (<a href='/cgit.cgi/linux/net-next.git/patch/net/irda/irnet/Makefile?id=69973b830859bc6529a7a0468ba0d80ee5117826'>patch</a>)</td></tr>
<tr><th>tree</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/tree/?id=69973b830859bc6529a7a0468ba0d80ee5117826'>5f11fe15ed9d9a3ab9c92242030e54b73ecdce45</a> /<a href='/cgit.cgi/linux/net-next.git/tree/net/irda/irnet/Makefile?id=69973b830859bc6529a7a0468ba0d80ee5117826'>net/irda/irnet/Makefile</a></td></tr>
<tr><th>parent</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/net/irda/irnet/Makefile?id=2e4333c14de06a333783d6812cf3c4998f78b0c8'>2e4333c14de06a333783d6812cf3c4998f78b0c8</a> (<a href='/cgit.cgi/linux/net-next.git/diff/net/irda/irnet/Makefile?id=69973b830859bc6529a7a0468ba0d80ee5117826&amp;id2=2e4333c14de06a333783d6812cf3c4998f78b0c8'>diff</a>)</td></tr></table>
<div class='commit-subject'>Linux 4.9</div><div class='commit-msg'></div><div class='diffstat-header'><a href='/cgit.cgi/linux/net-next.git/diff/?id=69973b830859bc6529a7a0468ba0d80ee5117826'>Diffstat</a> (limited to 'net/irda/irnet/Makefile')</div><table summary='diffstat' class='diffstat'>