diff options
author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 18:49:45 +0000 |
---|---|---|
committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 18:49:45 +0000 |
commit | 2c3c1048746a4622d8c89a29670120dc8fab93c4 (patch) | |
tree | 848558de17fb3008cdf4d861b01ac7781903ce39 /drivers/usb/mon/mon_main.c | |
parent | Initial commit. (diff) | |
download | linux-2c3c1048746a4622d8c89a29670120dc8fab93c4.tar.xz linux-2c3c1048746a4622d8c89a29670120dc8fab93c4.zip |
Adding upstream version 6.1.76.upstream/6.1.76upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'drivers/usb/mon/mon_main.c')
-rw-r--r-- | drivers/usb/mon/mon_main.c | 435 |
1 files changed, 435 insertions, 0 deletions
diff --git a/drivers/usb/mon/mon_main.c b/drivers/usb/mon/mon_main.c new file mode 100644 index 000000000..9812d102a --- /dev/null +++ b/drivers/usb/mon/mon_main.c @@ -0,0 +1,435 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * The USB Monitor, inspired by Dave Harding's USBMon. + * + * mon_main.c: Main file, module initiation and exit, registrations, etc. + * + * Copyright (C) 2005 Pete Zaitcev (zaitcev@redhat.com) + */ + +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/usb.h> +#include <linux/usb/hcd.h> +#include <linux/slab.h> +#include <linux/notifier.h> +#include <linux/mutex.h> + +#include "usb_mon.h" + + +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 usb_bus *ubus); + +DEFINE_MUTEX(mon_lock); + +struct mon_bus mon_bus0; /* Pseudo bus meaning "all buses" */ +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 list_head *p; + + spin_lock_irqsave(&mbus->lock, flags); + if (mbus->nreaders == 0) { + if (mbus == &mon_bus0) { + list_for_each (p, &mon_buses) { + struct mon_bus *m1; + m1 = list_entry(p, struct mon_bus, bus_link); + m1->u_bus->monitored = 1; + } + } else { + mbus->u_bus->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_bus_submit(struct mon_bus *mbus, struct urb *urb) +{ + unsigned long flags; + struct list_head *pos; + struct mon_reader *r; + + spin_lock_irqsave(&mbus->lock, flags); + mbus->cnt_events++; + 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); +} + +static void mon_submit(struct usb_bus *ubus, struct urb *urb) +{ + struct mon_bus *mbus; + + mbus = ubus->mon_bus; + if (mbus != NULL) + mon_bus_submit(mbus, urb); + mon_bus_submit(&mon_bus0, urb); +} + +/* + */ +static void mon_bus_submit_error(struct mon_bus *mbus, struct urb *urb, int error) +{ + unsigned long flags; + struct list_head *pos; + struct mon_reader *r; + + spin_lock_irqsave(&mbus->lock, flags); + mbus->cnt_events++; + list_for_each (pos, &mbus->r_list) { + r = list_entry(pos, struct mon_reader, r_link); + r->rnf_error(r->r_data, urb, error); + } + spin_unlock_irqrestore(&mbus->lock, flags); +} + +static void mon_submit_error(struct usb_bus *ubus, struct urb *urb, int error) +{ + struct mon_bus *mbus; + + mbus = ubus->mon_bus; + if (mbus != NULL) + mon_bus_submit_error(mbus, urb, error); + mon_bus_submit_error(&mon_bus0, urb, error); +} + +/* + */ +static void mon_bus_complete(struct mon_bus *mbus, struct urb *urb, int status) +{ + unsigned long flags; + struct list_head *pos; + struct mon_reader *r; + + spin_lock_irqsave(&mbus->lock, flags); + mbus->cnt_events++; + list_for_each (pos, &mbus->r_list) { + r = list_entry(pos, struct mon_reader, r_link); + r->rnf_complete(r->r_data, urb, status); + } + spin_unlock_irqrestore(&mbus->lock, flags); +} + +static void mon_complete(struct usb_bus *ubus, struct urb *urb, int status) +{ + struct mon_bus *mbus; + + mbus = ubus->mon_bus; + if (mbus != NULL) + mon_bus_complete(mbus, urb, status); + mon_bus_complete(&mon_bus0, urb, status); +} + +/* int (*unlink_urb) (struct urb *urb, int status); */ + +/* + * Stop monitoring. + */ +static void mon_stop(struct mon_bus *mbus) +{ + struct usb_bus *ubus; + struct list_head *p; + + if (mbus == &mon_bus0) { + list_for_each (p, &mon_buses) { + mbus = list_entry(p, struct mon_bus, bus_link); + /* + * We do not change nreaders here, so rely on mon_lock. + */ + if (mbus->nreaders == 0 && (ubus = mbus->u_bus) != NULL) + ubus->monitored = 0; + } + } else { + /* + * A stop can be called for a dissolved mon_bus in case of + * a reader staying across an rmmod foo_hcd, so test ->u_bus. + */ + if (mon_bus0.nreaders == 0 && (ubus = mbus->u_bus) != 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(ubus); + mutex_lock(&mon_lock); + if (mon_bus0.nreaders != 0) + ubus->monitored = 1; + mutex_unlock(&mon_lock); +} + +/* + * 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; + + mutex_lock(&mon_lock); + list_del(&mbus->bus_link); + if (mbus->text_inited) + mon_text_del(mbus); + if (mbus->bin_inited) + mon_bin_del(mbus); + + mon_dissolve(mbus, ubus); + kref_put(&mbus->ref, mon_bus_drop); + mutex_unlock(&mon_lock); +} + +static int mon_notify(struct notifier_block *self, unsigned long action, + void *dev) +{ + switch (action) { + case USB_BUS_ADD: + mon_bus_add(dev); + break; + case USB_BUS_REMOVE: + mon_bus_remove(dev); + } + return NOTIFY_OK; +} + +static struct notifier_block mon_nb = { + .notifier_call = mon_notify, +}; + +/* + * Ops + */ +static const struct usb_mon_operations mon_ops_0 = { + .urb_submit = mon_submit, + .urb_submit_error = mon_submit_error, + .urb_complete = mon_complete, +}; + +/* + * Tear usb_bus and mon_bus apart. + */ +static void mon_dissolve(struct mon_bus *mbus, struct usb_bus *ubus) +{ + + if (ubus->monitored) { + ubus->monitored = 0; + mb(); + } + + ubus->mon_bus = NULL; + mbus->u_bus = NULL; + mb(); + + /* We want synchronize_irq() here, but that needs an argument. */ +} + +/* + */ +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 usb_bus *ubus) +{ + struct mon_bus *mbus; + + mbus = kzalloc(sizeof(struct mon_bus), GFP_KERNEL); + if (mbus == NULL) + goto err_alloc; + kref_init(&mbus->ref); + spin_lock_init(&mbus->lock); + INIT_LIST_HEAD(&mbus->r_list); + + /* + * We don't need to take a reference to ubus, because we receive + * a notification if the bus is about to be removed. + */ + mbus->u_bus = ubus; + ubus->mon_bus = mbus; + + mbus->text_inited = mon_text_add(mbus, ubus); + mbus->bin_inited = mon_bin_add(mbus, ubus); + + mutex_lock(&mon_lock); + list_add_tail(&mbus->bus_link, &mon_buses); + mutex_unlock(&mon_lock); + return; + +err_alloc: + return; +} + +static void mon_bus0_init(void) +{ + struct mon_bus *mbus = &mon_bus0; + + kref_init(&mbus->ref); + spin_lock_init(&mbus->lock); + INIT_LIST_HEAD(&mbus->r_list); + + mbus->text_inited = mon_text_add(mbus, NULL); + mbus->bin_inited = mon_bin_add(mbus, NULL); +} + +/* + * Search a USB bus by number. Notice that USB bus numbers start from one, + * which we may later use to identify "all" with zero. + * + * This function must be called with mon_lock held. + * + * This is obviously inefficient and may be revised in the future. + */ +struct mon_bus *mon_bus_lookup(unsigned int num) +{ + struct list_head *p; + struct mon_bus *mbus; + + if (num == 0) { + return &mon_bus0; + } + list_for_each (p, &mon_buses) { + mbus = list_entry(p, struct mon_bus, bus_link); + if (mbus->u_bus->busnum == num) { + return mbus; + } + } + return NULL; +} + +static int __init mon_init(void) +{ + struct usb_bus *ubus; + int rc, id; + + if ((rc = mon_text_init()) != 0) + goto err_text; + if ((rc = mon_bin_init()) != 0) + goto err_bin; + + mon_bus0_init(); + + if (usb_mon_register(&mon_ops_0) != 0) { + printk(KERN_NOTICE TAG ": unable to register with the core\n"); + rc = -ENODEV; + goto err_reg; + } + // MOD_INC_USE_COUNT(which_module?); + + mutex_lock(&usb_bus_idr_lock); + idr_for_each_entry(&usb_bus_idr, ubus, id) + mon_bus_init(ubus); + usb_register_notify(&mon_nb); + mutex_unlock(&usb_bus_idr_lock); + return 0; + +err_reg: + mon_bin_exit(); +err_bin: + mon_text_exit(); +err_text: + return rc; +} + +static void __exit mon_exit(void) +{ + struct mon_bus *mbus; + struct list_head *p; + + usb_unregister_notify(&mon_nb); + usb_mon_deregister(); + + 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); + kref_get(&mbus->ref); /* 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"); |