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path: root/drivers/usb/mon/mon_main.c
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Diffstat (limited to 'drivers/usb/mon/mon_main.c')
-rw-r--r--drivers/usb/mon/mon_main.c377
1 files changed, 377 insertions, 0 deletions
diff --git a/drivers/usb/mon/mon_main.c b/drivers/usb/mon/mon_main.c
new file mode 100644
index 00000000000..aa9d00808e4
--- /dev/null
+++ b/drivers/usb/mon/mon_main.c
@@ -0,0 +1,377 @@
+/*
+ * The USB Monitor, inspired by Dave Harding's USBMon.
+ *
+ * mon_main.c: Main file, module initiation and exit, registrations, etc.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/usb.h>
+#include <linux/debugfs.h>
+#include <linux/smp_lock.h>
+
+#include "usb_mon.h"
+#include "../core/hcd.h"
+
+static void mon_submit(struct usb_bus *ubus, struct urb *urb);
+static void mon_complete(struct usb_bus *ubus, struct urb *urb);
+static void mon_stop(struct mon_bus *mbus);
+static void mon_dissolve(struct mon_bus *mbus, struct usb_bus *ubus);
+static void mon_bus_drop(struct kref *r);
+static void mon_bus_init(struct dentry *mondir, struct usb_bus *ubus);
+
+DECLARE_MUTEX(mon_lock);
+
+static struct dentry *mon_dir; /* /dbg/usbmon */
+static LIST_HEAD(mon_buses); /* All buses we know: struct mon_bus */
+
+/*
+ * Link a reader into the bus.
+ *
+ * This must be called with mon_lock taken because of mbus->ref.
+ */
+void mon_reader_add(struct mon_bus *mbus, struct mon_reader *r)
+{
+ unsigned long flags;
+ struct usb_bus *ubus;
+
+ spin_lock_irqsave(&mbus->lock, flags);
+ if (mbus->nreaders == 0) {
+ ubus = mbus->u_bus;
+ if (ubus->monitored) {
+ /*
+ * Something is really broken, refuse to go on and
+ * possibly corrupt ops pointers or worse.
+ */
+ printk(KERN_ERR TAG ": bus %d is already monitored\n",
+ ubus->busnum);
+ spin_unlock_irqrestore(&mbus->lock, flags);
+ return;
+ }
+ ubus->monitored = 1;
+ }
+ mbus->nreaders++;
+ list_add_tail(&r->r_link, &mbus->r_list);
+ spin_unlock_irqrestore(&mbus->lock, flags);
+
+ kref_get(&mbus->ref);
+}
+
+/*
+ * Unlink reader from the bus.
+ *
+ * This is called with mon_lock taken, so we can decrement mbus->ref.
+ */
+void mon_reader_del(struct mon_bus *mbus, struct mon_reader *r)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(&mbus->lock, flags);
+ list_del(&r->r_link);
+ --mbus->nreaders;
+ if (mbus->nreaders == 0)
+ mon_stop(mbus);
+ spin_unlock_irqrestore(&mbus->lock, flags);
+
+ kref_put(&mbus->ref, mon_bus_drop);
+}
+
+/*
+ */
+static void mon_submit(struct usb_bus *ubus, struct urb *urb)
+{
+ struct mon_bus *mbus;
+ unsigned long flags;
+ struct list_head *pos;
+ struct mon_reader *r;
+
+ mbus = ubus->mon_bus;
+ if (mbus == NULL)
+ goto out_unlocked;
+
+ spin_lock_irqsave(&mbus->lock, flags);
+ if (mbus->nreaders == 0)
+ goto out_locked;
+
+ list_for_each (pos, &mbus->r_list) {
+ r = list_entry(pos, struct mon_reader, r_link);
+ r->rnf_submit(r->r_data, urb);
+ }
+
+ spin_unlock_irqrestore(&mbus->lock, flags);
+ return;
+
+out_locked:
+ spin_unlock_irqrestore(&mbus->lock, flags);
+out_unlocked:
+ return;
+}
+
+/*
+ */
+static void mon_submit_error(struct usb_bus *ubus, struct urb *urb, int err)
+{
+ struct mon_bus *mbus;
+
+ mbus = ubus->mon_bus;
+ if (mbus == NULL)
+ goto out_unlocked;
+
+ /*
+ * XXX Capture the error code and the 'E' event.
+ */
+
+ return;
+
+out_unlocked:
+ return;
+}
+
+/*
+ */
+static void mon_complete(struct usb_bus *ubus, struct urb *urb)
+{
+ struct mon_bus *mbus;
+ unsigned long flags;
+ struct list_head *pos;
+ struct mon_reader *r;
+
+ mbus = ubus->mon_bus;
+ if (mbus == NULL) {
+ /*
+ * This should not happen.
+ * At this point we do not even know the bus number...
+ */
+ printk(KERN_ERR TAG ": Null mon bus in URB, pipe 0x%x\n",
+ urb->pipe);
+ return;
+ }
+
+ spin_lock_irqsave(&mbus->lock, flags);
+ list_for_each (pos, &mbus->r_list) {
+ r = list_entry(pos, struct mon_reader, r_link);
+ r->rnf_complete(r->r_data, urb);
+ }
+ spin_unlock_irqrestore(&mbus->lock, flags);
+}
+
+/* int (*unlink_urb) (struct urb *urb, int status); */
+
+/*
+ * Stop monitoring.
+ * Obviously this must be well locked, so no need to play with mb's.
+ */
+static void mon_stop(struct mon_bus *mbus)
+{
+ struct usb_bus *ubus = mbus->u_bus;
+
+ /*
+ * A stop can be called for a dissolved mon_bus in case of
+ * a reader staying across an rmmod foo_hcd.
+ */
+ if (ubus != NULL) {
+ ubus->monitored = 0;
+ mb();
+ }
+}
+
+/*
+ * Add a USB bus (usually by a modprobe foo-hcd)
+ *
+ * This does not return an error code because the core cannot care less
+ * if monitoring is not established.
+ */
+static void mon_bus_add(struct usb_bus *ubus)
+{
+ mon_bus_init(mon_dir, ubus);
+}
+
+/*
+ * Remove a USB bus (either from rmmod foo-hcd or from a hot-remove event).
+ */
+static void mon_bus_remove(struct usb_bus *ubus)
+{
+ struct mon_bus *mbus = ubus->mon_bus;
+
+ down(&mon_lock);
+ list_del(&mbus->bus_link);
+ debugfs_remove(mbus->dent_t);
+ debugfs_remove(mbus->dent_s);
+
+ mon_dissolve(mbus, ubus);
+ kref_put(&mbus->ref, mon_bus_drop);
+ up(&mon_lock);
+}
+
+/*
+ * Ops
+ */
+static struct usb_mon_operations mon_ops_0 = {
+ .urb_submit = mon_submit,
+ .urb_submit_error = mon_submit_error,
+ .urb_complete = mon_complete,
+ .bus_add = mon_bus_add,
+ .bus_remove = mon_bus_remove,
+};
+
+/*
+ * Tear usb_bus and mon_bus apart.
+ */
+static void mon_dissolve(struct mon_bus *mbus, struct usb_bus *ubus)
+{
+
+ /*
+ * Never happens, but...
+ */
+ if (ubus->monitored) {
+ printk(KERN_ERR TAG ": bus %d is dissolved while monitored\n",
+ ubus->busnum);
+ ubus->monitored = 0;
+ mb();
+ }
+
+ ubus->mon_bus = NULL;
+ mbus->u_bus = NULL;
+ mb();
+ // usb_bus_put(ubus);
+}
+
+/*
+ */
+static void mon_bus_drop(struct kref *r)
+{
+ struct mon_bus *mbus = container_of(r, struct mon_bus, ref);
+ kfree(mbus);
+}
+
+/*
+ * Initialize a bus for us:
+ * - allocate mon_bus
+ * - refcount USB bus struct
+ * - link
+ */
+static void mon_bus_init(struct dentry *mondir, struct usb_bus *ubus)
+{
+ struct dentry *d;
+ struct mon_bus *mbus;
+ enum { NAMESZ = 10 };
+ char name[NAMESZ];
+ int rc;
+
+ if ((mbus = kmalloc(sizeof(struct mon_bus), GFP_KERNEL)) == NULL)
+ goto err_alloc;
+ memset(mbus, 0, sizeof(struct mon_bus));
+ kref_init(&mbus->ref);
+ spin_lock_init(&mbus->lock);
+ INIT_LIST_HEAD(&mbus->r_list);
+
+ /*
+ * This usb_bus_get here is superfluous, because we receive
+ * a notification if usb_bus is about to be removed.
+ */
+ // usb_bus_get(ubus);
+ mbus->u_bus = ubus;
+ ubus->mon_bus = mbus;
+
+ rc = snprintf(name, NAMESZ, "%dt", ubus->busnum);
+ if (rc <= 0 || rc >= NAMESZ)
+ goto err_print_t;
+ d = debugfs_create_file(name, 0600, mondir, mbus, &mon_fops_text);
+ if (d == NULL)
+ goto err_create_t;
+ mbus->dent_t = d;
+
+ rc = snprintf(name, NAMESZ, "%ds", ubus->busnum);
+ if (rc <= 0 || rc >= NAMESZ)
+ goto err_print_s;
+ d = debugfs_create_file(name, 0600, mondir, mbus, &mon_fops_stat);
+ if (d == NULL)
+ goto err_create_s;
+ mbus->dent_s = d;
+
+ down(&mon_lock);
+ list_add_tail(&mbus->bus_link, &mon_buses);
+ up(&mon_lock);
+ return;
+
+err_create_s:
+err_print_s:
+ debugfs_remove(mbus->dent_t);
+err_create_t:
+err_print_t:
+ kfree(mbus);
+err_alloc:
+ return;
+}
+
+static int __init mon_init(void)
+{
+ struct usb_bus *ubus;
+ struct dentry *mondir;
+
+ mondir = debugfs_create_dir("usbmon", NULL);
+ if (IS_ERR(mondir)) {
+ printk(KERN_NOTICE TAG ": debugs is not available\n");
+ return -ENODEV;
+ }
+ if (mondir == NULL) {
+ printk(KERN_NOTICE TAG ": unable to create usbmon directory\n");
+ return -ENODEV;
+ }
+ mon_dir = mondir;
+
+ if (usb_mon_register(&mon_ops_0) != 0) {
+ printk(KERN_NOTICE TAG ": unable to register with the core\n");
+ debugfs_remove(mondir);
+ return -ENODEV;
+ }
+ // MOD_INC_USE_COUNT(which_module?);
+
+ down(&usb_bus_list_lock);
+ list_for_each_entry (ubus, &usb_bus_list, bus_list) {
+ mon_bus_init(mondir, ubus);
+ }
+ up(&usb_bus_list_lock);
+ return 0;
+}
+
+static void __exit mon_exit(void)
+{
+ struct mon_bus *mbus;
+ struct list_head *p;
+
+ usb_mon_deregister();
+
+ down(&mon_lock);
+ while (!list_empty(&mon_buses)) {
+ p = mon_buses.next;
+ mbus = list_entry(p, struct mon_bus, bus_link);
+ list_del(p);
+
+ debugfs_remove(mbus->dent_t);
+ debugfs_remove(mbus->dent_s);
+
+ /*
+ * 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);
+ }
+ up(&mon_lock);
+
+ debugfs_remove(mon_dir);
+}
+
+module_init(mon_init);
+module_exit(mon_exit);
+
+MODULE_LICENSE("GPL");