435 lines
9.1 KiB
C
435 lines
9.1 KiB
C
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/*
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* The USB Monitor, inspired by Dave Harding's USBMon.
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*
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* mon_main.c: Main file, module initiation and exit, registrations, etc.
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*
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* Copyright (C) 2005 Pete Zaitcev (zaitcev@redhat.com)
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*/
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/usb.h>
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#include <linux/usb/hcd.h>
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#include <linux/slab.h>
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#include <linux/notifier.h>
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#include <linux/mutex.h>
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#include "usb_mon.h"
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static void mon_stop(struct mon_bus *mbus);
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static void mon_dissolve(struct mon_bus *mbus, struct usb_bus *ubus);
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static void mon_bus_drop(struct kref *r);
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static void mon_bus_init(struct usb_bus *ubus);
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DEFINE_MUTEX(mon_lock);
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struct mon_bus mon_bus0; /* Pseudo bus meaning "all buses" */
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static LIST_HEAD(mon_buses); /* All buses we know: struct mon_bus */
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/*
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* Link a reader into the bus.
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*
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* This must be called with mon_lock taken because of mbus->ref.
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*/
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void mon_reader_add(struct mon_bus *mbus, struct mon_reader *r)
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{
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unsigned long flags;
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struct list_head *p;
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spin_lock_irqsave(&mbus->lock, flags);
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if (mbus->nreaders == 0) {
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if (mbus == &mon_bus0) {
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list_for_each (p, &mon_buses) {
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struct mon_bus *m1;
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m1 = list_entry(p, struct mon_bus, bus_link);
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m1->u_bus->monitored = 1;
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}
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} else {
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mbus->u_bus->monitored = 1;
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}
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}
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mbus->nreaders++;
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list_add_tail(&r->r_link, &mbus->r_list);
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spin_unlock_irqrestore(&mbus->lock, flags);
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kref_get(&mbus->ref);
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}
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/*
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* Unlink reader from the bus.
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*
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* This is called with mon_lock taken, so we can decrement mbus->ref.
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*/
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void mon_reader_del(struct mon_bus *mbus, struct mon_reader *r)
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{
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unsigned long flags;
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spin_lock_irqsave(&mbus->lock, flags);
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list_del(&r->r_link);
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--mbus->nreaders;
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if (mbus->nreaders == 0)
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mon_stop(mbus);
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spin_unlock_irqrestore(&mbus->lock, flags);
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kref_put(&mbus->ref, mon_bus_drop);
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}
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/*
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*/
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static void mon_bus_submit(struct mon_bus *mbus, struct urb *urb)
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{
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unsigned long flags;
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struct list_head *pos;
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struct mon_reader *r;
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spin_lock_irqsave(&mbus->lock, flags);
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mbus->cnt_events++;
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list_for_each (pos, &mbus->r_list) {
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r = list_entry(pos, struct mon_reader, r_link);
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r->rnf_submit(r->r_data, urb);
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}
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spin_unlock_irqrestore(&mbus->lock, flags);
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}
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static void mon_submit(struct usb_bus *ubus, struct urb *urb)
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{
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struct mon_bus *mbus;
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mbus = ubus->mon_bus;
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if (mbus != NULL)
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mon_bus_submit(mbus, urb);
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mon_bus_submit(&mon_bus0, urb);
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}
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/*
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*/
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static void mon_bus_submit_error(struct mon_bus *mbus, struct urb *urb, int error)
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{
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unsigned long flags;
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struct list_head *pos;
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struct mon_reader *r;
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spin_lock_irqsave(&mbus->lock, flags);
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mbus->cnt_events++;
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list_for_each (pos, &mbus->r_list) {
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r = list_entry(pos, struct mon_reader, r_link);
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r->rnf_error(r->r_data, urb, error);
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}
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spin_unlock_irqrestore(&mbus->lock, flags);
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}
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static void mon_submit_error(struct usb_bus *ubus, struct urb *urb, int error)
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{
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struct mon_bus *mbus;
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mbus = ubus->mon_bus;
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if (mbus != NULL)
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mon_bus_submit_error(mbus, urb, error);
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mon_bus_submit_error(&mon_bus0, urb, error);
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}
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/*
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*/
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static void mon_bus_complete(struct mon_bus *mbus, struct urb *urb, int status)
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{
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unsigned long flags;
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struct list_head *pos;
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struct mon_reader *r;
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spin_lock_irqsave(&mbus->lock, flags);
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mbus->cnt_events++;
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list_for_each (pos, &mbus->r_list) {
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r = list_entry(pos, struct mon_reader, r_link);
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r->rnf_complete(r->r_data, urb, status);
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}
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spin_unlock_irqrestore(&mbus->lock, flags);
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}
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static void mon_complete(struct usb_bus *ubus, struct urb *urb, int status)
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{
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struct mon_bus *mbus;
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mbus = ubus->mon_bus;
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if (mbus != NULL)
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mon_bus_complete(mbus, urb, status);
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mon_bus_complete(&mon_bus0, urb, status);
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}
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/* int (*unlink_urb) (struct urb *urb, int status); */
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/*
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* Stop monitoring.
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*/
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static void mon_stop(struct mon_bus *mbus)
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{
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struct usb_bus *ubus;
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struct list_head *p;
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if (mbus == &mon_bus0) {
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list_for_each (p, &mon_buses) {
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mbus = list_entry(p, struct mon_bus, bus_link);
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/*
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* We do not change nreaders here, so rely on mon_lock.
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*/
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if (mbus->nreaders == 0 && (ubus = mbus->u_bus) != NULL)
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ubus->monitored = 0;
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}
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} else {
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/*
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* A stop can be called for a dissolved mon_bus in case of
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* a reader staying across an rmmod foo_hcd, so test ->u_bus.
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*/
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if (mon_bus0.nreaders == 0 && (ubus = mbus->u_bus) != NULL) {
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ubus->monitored = 0;
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mb();
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}
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}
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}
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/*
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* Add a USB bus (usually by a modprobe foo-hcd)
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*
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* This does not return an error code because the core cannot care less
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* if monitoring is not established.
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*/
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static void mon_bus_add(struct usb_bus *ubus)
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{
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mon_bus_init(ubus);
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mutex_lock(&mon_lock);
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if (mon_bus0.nreaders != 0)
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ubus->monitored = 1;
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mutex_unlock(&mon_lock);
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}
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/*
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* Remove a USB bus (either from rmmod foo-hcd or from a hot-remove event).
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*/
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static void mon_bus_remove(struct usb_bus *ubus)
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{
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struct mon_bus *mbus = ubus->mon_bus;
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mutex_lock(&mon_lock);
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list_del(&mbus->bus_link);
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if (mbus->text_inited)
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mon_text_del(mbus);
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if (mbus->bin_inited)
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mon_bin_del(mbus);
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mon_dissolve(mbus, ubus);
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kref_put(&mbus->ref, mon_bus_drop);
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mutex_unlock(&mon_lock);
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}
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static int mon_notify(struct notifier_block *self, unsigned long action,
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void *dev)
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{
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switch (action) {
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case USB_BUS_ADD:
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mon_bus_add(dev);
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break;
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case USB_BUS_REMOVE:
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mon_bus_remove(dev);
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}
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return NOTIFY_OK;
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}
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static struct notifier_block mon_nb = {
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.notifier_call = mon_notify,
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};
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/*
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* Ops
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*/
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static const struct usb_mon_operations mon_ops_0 = {
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.urb_submit = mon_submit,
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.urb_submit_error = mon_submit_error,
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.urb_complete = mon_complete,
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};
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/*
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* Tear usb_bus and mon_bus apart.
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*/
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static void mon_dissolve(struct mon_bus *mbus, struct usb_bus *ubus)
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{
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if (ubus->monitored) {
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ubus->monitored = 0;
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mb();
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}
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ubus->mon_bus = NULL;
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mbus->u_bus = NULL;
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mb();
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/* We want synchronize_irq() here, but that needs an argument. */
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}
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/*
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*/
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static void mon_bus_drop(struct kref *r)
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{
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struct mon_bus *mbus = container_of(r, struct mon_bus, ref);
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kfree(mbus);
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}
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/*
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* Initialize a bus for us:
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* - allocate mon_bus
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* - refcount USB bus struct
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* - link
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*/
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static void mon_bus_init(struct usb_bus *ubus)
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{
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struct mon_bus *mbus;
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mbus = kzalloc(sizeof(struct mon_bus), GFP_KERNEL);
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if (mbus == NULL)
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goto err_alloc;
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kref_init(&mbus->ref);
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spin_lock_init(&mbus->lock);
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INIT_LIST_HEAD(&mbus->r_list);
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/*
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* We don't need to take a reference to ubus, because we receive
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* a notification if the bus is about to be removed.
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*/
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mbus->u_bus = ubus;
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ubus->mon_bus = mbus;
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mbus->text_inited = mon_text_add(mbus, ubus);
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mbus->bin_inited = mon_bin_add(mbus, ubus);
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mutex_lock(&mon_lock);
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list_add_tail(&mbus->bus_link, &mon_buses);
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mutex_unlock(&mon_lock);
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return;
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err_alloc:
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return;
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}
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static void mon_bus0_init(void)
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{
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struct mon_bus *mbus = &mon_bus0;
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kref_init(&mbus->ref);
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spin_lock_init(&mbus->lock);
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INIT_LIST_HEAD(&mbus->r_list);
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mbus->text_inited = mon_text_add(mbus, NULL);
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mbus->bin_inited = mon_bin_add(mbus, NULL);
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}
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/*
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* Search a USB bus by number. Notice that USB bus numbers start from one,
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* which we may later use to identify "all" with zero.
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*
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* This function must be called with mon_lock held.
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*
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* This is obviously inefficient and may be revised in the future.
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*/
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struct mon_bus *mon_bus_lookup(unsigned int num)
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{
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struct list_head *p;
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struct mon_bus *mbus;
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if (num == 0) {
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return &mon_bus0;
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}
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list_for_each (p, &mon_buses) {
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mbus = list_entry(p, struct mon_bus, bus_link);
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if (mbus->u_bus->busnum == num) {
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return mbus;
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}
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}
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return NULL;
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}
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static int __init mon_init(void)
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{
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struct usb_bus *ubus;
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int rc, id;
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if ((rc = mon_text_init()) != 0)
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goto err_text;
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if ((rc = mon_bin_init()) != 0)
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goto err_bin;
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mon_bus0_init();
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if (usb_mon_register(&mon_ops_0) != 0) {
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printk(KERN_NOTICE TAG ": unable to register with the core\n");
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rc = -ENODEV;
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goto err_reg;
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}
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// MOD_INC_USE_COUNT(which_module?);
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mutex_lock(&usb_bus_idr_lock);
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idr_for_each_entry(&usb_bus_idr, ubus, id)
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mon_bus_init(ubus);
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usb_register_notify(&mon_nb);
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mutex_unlock(&usb_bus_idr_lock);
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return 0;
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err_reg:
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mon_bin_exit();
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err_bin:
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mon_text_exit();
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err_text:
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return rc;
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}
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static void __exit mon_exit(void)
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{
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struct mon_bus *mbus;
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struct list_head *p;
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usb_unregister_notify(&mon_nb);
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usb_mon_deregister();
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mutex_lock(&mon_lock);
|
||
|
|
|
||
|
|
while (!list_empty(&mon_buses)) {
|
||
|
|
p = mon_buses.next;
|
||
|
|
mbus = list_entry(p, struct mon_bus, bus_link);
|
||
|
|
list_del(p);
|
||
|
|
|
||
|
|
if (mbus->text_inited)
|
||
|
|
mon_text_del(mbus);
|
||
|
|
if (mbus->bin_inited)
|
||
|
|
mon_bin_del(mbus);
|
||
|
|
|
||
|
|
/*
|
||
|
|
* This never happens, because the open/close paths in
|
||
|
|
* file level maintain module use counters and so rmmod fails
|
||
|
|
* before reaching here. However, better be safe...
|
||
|
|
*/
|
||
|
|
if (mbus->nreaders) {
|
||
|
|
printk(KERN_ERR TAG
|
||
|
|
": Outstanding opens (%d) on usb%d, leaking...\n",
|
||
|
|
mbus->nreaders, mbus->u_bus->busnum);
|
||
|
|
atomic_set(&mbus->ref.refcount, 2); /* Force leak */
|
||
|
|
}
|
||
|
|
|
||
|
|
mon_dissolve(mbus, mbus->u_bus);
|
||
|
|
kref_put(&mbus->ref, mon_bus_drop);
|
||
|
|
}
|
||
|
|
|
||
|
|
mbus = &mon_bus0;
|
||
|
|
if (mbus->text_inited)
|
||
|
|
mon_text_del(mbus);
|
||
|
|
if (mbus->bin_inited)
|
||
|
|
mon_bin_del(mbus);
|
||
|
|
|
||
|
|
mutex_unlock(&mon_lock);
|
||
|
|
|
||
|
|
mon_text_exit();
|
||
|
|
mon_bin_exit();
|
||
|
|
}
|
||
|
|
|
||
|
|
module_init(mon_init);
|
||
|
|
module_exit(mon_exit);
|
||
|
|
|
||
|
|
MODULE_LICENSE("GPL");
|