drivers/usb/usbip/stub_main.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0+
 /*
  * Copyright (C) 2003-2008 Takahiro Hirofuchi
  */

 #include <linux/string.h>
 #include <linux/module.h>
 #include <linux/device.h>

 #include "usbip_common.h"
 #include "stub.h"

 #define DRIVER_AUTHOR "Takahiro Hirofuchi"
 #define DRIVER_DESC "USB/IP Host Driver"

 struct kmem_cache *stub_priv_cache;

 /*
  * busid_tables defines matching busids that usbip can grab. A user can change
  * dynamically what device is locally used and what device is exported to a
  * remote host.
  */
 #define MAX_BUSID 16
 static struct bus_id_priv busid_table[MAX_BUSID];
 static spinlock_t busid_table_lock;

 static void init_busid_table(void)
 {
 	int i;

 	/*
 	 * This also sets the bus_table[i].status to
 	 * STUB_BUSID_OTHER, which is 0.
 	 */
 	memset(busid_table, 0, sizeof(busid_table));

 	spin_lock_init(&busid_table_lock);

 	for (i = 0; i < MAX_BUSID; i++)
 		spin_lock_init(&busid_table[i].busid_lock);
 }

 /*
  * Find the index of the busid by name.
  * Must be called with busid_table_lock held.
  */
 static int get_busid_idx(const char *busid)
 {
 	int i;
 	int idx = -1;

 	for (i = 0; i < MAX_BUSID; i++) {
 		spin_lock(&busid_table[i].busid_lock);
 		if (busid_table[i].name[0])
 			if (!strncmp(busid_table[i].name, busid, BUSID_SIZE)) {
 				idx = i;
 				spin_unlock(&busid_table[i].busid_lock);
 				break;
 			}
 		spin_unlock(&busid_table[i].busid_lock);
 	}
 	return idx;
 }

 /* Returns holding busid_lock. Should call put_busid_priv() to unlock */
 struct bus_id_priv *get_busid_priv(const char *busid)
 {
 	int idx;
 	struct bus_id_priv *bid = NULL;

 	spin_lock(&busid_table_lock);
 	idx = get_busid_idx(busid);
 	if (idx >= 0) {
 		bid = &(busid_table[idx]);
 		/* get busid_lock before returning */
 		spin_lock(&bid->busid_lock);
 	}
 	spin_unlock(&busid_table_lock);

 	return bid;
 }

 void put_busid_priv(struct bus_id_priv *bid)
 {
 	if (bid)
 		spin_unlock(&bid->busid_lock);
 }

 static int add_match_busid(char *busid)
 {
 	int i;
 	int ret = -1;

 	spin_lock(&busid_table_lock);
 	/* already registered? */
 	if (get_busid_idx(busid) >= 0) {
 		ret = 0;
 		goto out;
 	}

 	for (i = 0; i < MAX_BUSID; i++) {
 		spin_lock(&busid_table[i].busid_lock);
 		if (!busid_table[i].name[0]) {
 			strlcpy(busid_table[i].name, busid, BUSID_SIZE);
 			if ((busid_table[i].status != STUB_BUSID_ALLOC) &&
 			    (busid_table[i].status != STUB_BUSID_REMOV))
 				busid_table[i].status = STUB_BUSID_ADDED;
 			ret = 0;
 			spin_unlock(&busid_table[i].busid_lock);
 			break;
 		}
 		spin_unlock(&busid_table[i].busid_lock);
 	}

 out:
 	spin_unlock(&busid_table_lock);

 	return ret;
 }

 int del_match_busid(char *busid)
 {
 	int idx;
 	int ret = -1;

 	spin_lock(&busid_table_lock);
 	idx = get_busid_idx(busid);
 	if (idx < 0)
 		goto out;

 	/* found */
 	ret = 0;

 	spin_lock(&busid_table[idx].busid_lock);

 	if (busid_table[idx].status == STUB_BUSID_OTHER)
 		memset(busid_table[idx].name, 0, BUSID_SIZE);

 	if ((busid_table[idx].status != STUB_BUSID_OTHER) &&
 	    (busid_table[idx].status != STUB_BUSID_ADDED))
 		busid_table[idx].status = STUB_BUSID_REMOV;

 	spin_unlock(&busid_table[idx].busid_lock);
 out:
 	spin_unlock(&busid_table_lock);

 	return ret;
 }

 static ssize_t match_busid_show(struct device_driver *drv, char *buf)
 {
 	int i;
 	char *out = buf;

 	spin_lock(&busid_table_lock);
 	for (i = 0; i < MAX_BUSID; i++) {
 		spin_lock(&busid_table[i].busid_lock);
 		if (busid_table[i].name[0])
 			out += sprintf(out, "%s ", busid_table[i].name);
 		spin_unlock(&busid_table[i].busid_lock);
 	}
 	spin_unlock(&busid_table_lock);
 	out += sprintf(out, "\n");

 	return out - buf;
 }

 static ssize_t match_busid_store(struct device_driver *dev, const char *buf,
 				 size_t count)
 {
 	int len;
 	char busid[BUSID_SIZE];

 	if (count < 5)
 		return -EINVAL;

 	/* busid needs to include \0 termination */
 	len = strlcpy(busid, buf + 4, BUSID_SIZE);
 	if (sizeof(busid) <= len)
 		return -EINVAL;

 	if (!strncmp(buf, "add ", 4)) {
 		if (add_match_busid(busid) < 0)
 			return -ENOMEM;

 		pr_debug("add busid %s\n", busid);
 		return count;
 	}

 	if (!strncmp(buf, "del ", 4)) {
 		if (del_match_busid(busid) < 0)
 			return -ENODEV;

 		pr_debug("del busid %s\n", busid);
 		return count;
 	}

 	return -EINVAL;
 }
 static DRIVER_ATTR_RW(match_busid);

 static int do_rebind(char *busid, struct bus_id_priv *busid_priv)
 {
 	int ret;

 	/* device_attach() callers should hold parent lock for USB */
 	if (busid_priv->udev->dev.parent)
 		device_lock(busid_priv->udev->dev.parent);
 	ret = device_attach(&busid_priv->udev->dev);
 	if (busid_priv->udev->dev.parent)
 		device_unlock(busid_priv->udev->dev.parent);
 	if (ret < 0) {
 		dev_err(&busid_priv->udev->dev, "rebind failed\n");
 		return ret;
 	}
 	return 0;
 }

 static void stub_device_rebind(void)
 {
 #if IS_MODULE(CONFIG_USBIP_HOST)
 	struct bus_id_priv *busid_priv;
 	int i;

 	/* update status to STUB_BUSID_OTHER so probe ignores the device */
 	spin_lock(&busid_table_lock);
 	for (i = 0; i < MAX_BUSID; i++) {
 		if (busid_table[i].name[0] &&
 		    busid_table[i].shutdown_busid) {
 			busid_priv = &(busid_table[i]);
 			busid_priv->status = STUB_BUSID_OTHER;
 		}
 	}
 	spin_unlock(&busid_table_lock);

 	/* now run rebind - no need to hold locks. driver files are removed */
 	for (i = 0; i < MAX_BUSID; i++) {
 		if (busid_table[i].name[0] &&
 		    busid_table[i].shutdown_busid) {
 			busid_priv = &(busid_table[i]);
 			do_rebind(busid_table[i].name, busid_priv);
 		}
 	}
 #endif
 }

 static ssize_t rebind_store(struct device_driver *dev, const char *buf,
 				 size_t count)
 {
 	int ret;
 	int len;
 	struct bus_id_priv *bid;

 	/* buf length should be less that BUSID_SIZE */
 	len = strnlen(buf, BUSID_SIZE);

 	if (!(len < BUSID_SIZE))
 		return -EINVAL;

 	bid = get_busid_priv(buf);
 	if (!bid)
 		return -ENODEV;

 	/* mark the device for deletion so probe ignores it during rescan */
 	bid->status = STUB_BUSID_OTHER;
 	/* release the busid lock */
 	put_busid_priv(bid);

 	ret = do_rebind((char *) buf, bid);
 	if (ret < 0)
 		return ret;

 	/* delete device from busid_table */
 	del_match_busid((char *) buf);

 	return count;
 }

 static DRIVER_ATTR_WO(rebind);

 static struct stub_priv *stub_priv_pop_from_listhead(struct list_head *listhead)
 {
 	struct stub_priv *priv, *tmp;

 	list_for_each_entry_safe(priv, tmp, listhead, list) {
 		list_del(&priv->list);
 		return priv;
 	}

 	return NULL;
 }

 static struct stub_priv *stub_priv_pop(struct stub_device *sdev)
 {
 	unsigned long flags;
 	struct stub_priv *priv;

 	spin_lock_irqsave(&sdev->priv_lock, flags);

 	priv = stub_priv_pop_from_listhead(&sdev->priv_init);
 	if (priv)
 		goto done;

 	priv = stub_priv_pop_from_listhead(&sdev->priv_tx);
 	if (priv)
 		goto done;

 	priv = stub_priv_pop_from_listhead(&sdev->priv_free);

 done:
 	spin_unlock_irqrestore(&sdev->priv_lock, flags);

 	return priv;
 }

 void stub_device_cleanup_urbs(struct stub_device *sdev)
 {
 	struct stub_priv *priv;
 	struct urb *urb;

 	dev_dbg(&sdev->udev->dev, "Stub device cleaning up urbs\n");

 	while ((priv = stub_priv_pop(sdev))) {
 		urb = priv->urb;
 		dev_dbg(&sdev->udev->dev, "free urb seqnum %lu\n",
 			priv->seqnum);
 		usb_kill_urb(urb);

 		kmem_cache_free(stub_priv_cache, priv);

 		kfree(urb->transfer_buffer);
 		urb->transfer_buffer = NULL;

 		kfree(urb->setup_packet);
 		urb->setup_packet = NULL;

 		usb_free_urb(urb);
 	}
 }

 static int __init usbip_host_init(void)
 {
 	int ret;

 	init_busid_table();

 	stub_priv_cache = KMEM_CACHE(stub_priv, SLAB_HWCACHE_ALIGN);
 	if (!stub_priv_cache) {
 		pr_err("kmem_cache_create failed\n");
 		return -ENOMEM;
 	}

 	ret = usb_register_device_driver(&stub_driver, THIS_MODULE);
 	if (ret) {
 		pr_err("usb_register failed %d\n", ret);
 		goto err_usb_register;
 	}

 	ret = driver_create_file(&stub_driver.drvwrap.driver,
 				 &driver_attr_match_busid);
 	if (ret) {
 		pr_err("driver_create_file failed\n");
 		goto err_create_file;
 	}

 	ret = driver_create_file(&stub_driver.drvwrap.driver,
 				 &driver_attr_rebind);
 	if (ret) {
 		pr_err("driver_create_file failed\n");
 		goto err_create_file;
 	}

 	return ret;

 err_create_file:
 	usb_deregister_device_driver(&stub_driver);
 err_usb_register:
 	kmem_cache_destroy(stub_priv_cache);
 	return ret;
 }

 static void __exit usbip_host_exit(void)
 {
 	driver_remove_file(&stub_driver.drvwrap.driver,
 			   &driver_attr_match_busid);

 	driver_remove_file(&stub_driver.drvwrap.driver,
 			   &driver_attr_rebind);

 	/*
 	 * deregister() calls stub_disconnect() for all devices. Device
 	 * specific data is cleared in stub_disconnect().
 	 */
 	usb_deregister_device_driver(&stub_driver);

 	/* initiate scan to attach devices */
 	stub_device_rebind();

 	kmem_cache_destroy(stub_priv_cache);
 }

 module_init(usbip_host_init);
 module_exit(usbip_host_exit);

 MODULE_AUTHOR(DRIVER_AUTHOR);
 MODULE_DESCRIPTION(DRIVER_DESC);
 MODULE_LICENSE("GPL");
	// SPDX-License-Identifier: GPL-2.0+
	/*
	* Copyright (C) 2003-2008 Takahiro Hirofuchi
	*/

	#include <linux/string.h>
	#include <linux/module.h>
	#include <linux/device.h>

	#include "usbip_common.h"
	#include "stub.h"

	#define DRIVER_AUTHOR "Takahiro Hirofuchi"
	#define DRIVER_DESC "USB/IP Host Driver"

	struct kmem_cache *stub_priv_cache;

	/*
	* busid_tables defines matching busids that usbip can grab. A user can change
	* dynamically what device is locally used and what device is exported to a
	* remote host.
	*/
	#define MAX_BUSID 16
	static struct bus_id_priv busid_table[MAX_BUSID];
	static spinlock_t busid_table_lock;

	static void init_busid_table(void)
	{
	int i;

	/*
	* This also sets the bus_table[i].status to
	* STUB_BUSID_OTHER, which is 0.
	*/
	memset(busid_table, 0, sizeof(busid_table));

	spin_lock_init(&busid_table_lock);

	for (i = 0; i < MAX_BUSID; i++)
	spin_lock_init(&busid_table[i].busid_lock);
	}

	/*
	* Find the index of the busid by name.
	* Must be called with busid_table_lock held.
	*/
	static int get_busid_idx(const char *busid)
	{
	int i;
	int idx = -1;

	for (i = 0; i < MAX_BUSID; i++) {
	spin_lock(&busid_table[i].busid_lock);
	if (busid_table[i].name[0])
	if (!strncmp(busid_table[i].name, busid, BUSID_SIZE)) {
	idx = i;
	spin_unlock(&busid_table[i].busid_lock);
	break;
	}
	spin_unlock(&busid_table[i].busid_lock);
	}
	return idx;
	}

	/* Returns holding busid_lock. Should call put_busid_priv() to unlock */
	struct bus_id_priv get_busid_priv(const char busid)
	{
	int idx;
	struct bus_id_priv *bid = NULL;

	spin_lock(&busid_table_lock);
	idx = get_busid_idx(busid);
	if (idx >= 0) {
	bid = &(busid_table[idx]);
	/* get busid_lock before returning */
	spin_lock(&bid->busid_lock);
	}
	spin_unlock(&busid_table_lock);

	return bid;
	}

	void put_busid_priv(struct bus_id_priv *bid)
	{
	if (bid)
	spin_unlock(&bid->busid_lock);
	}

	static int add_match_busid(char *busid)
	{
	int i;
	int ret = -1;

	spin_lock(&busid_table_lock);
	/* already registered? */
	if (get_busid_idx(busid) >= 0) {
	ret = 0;
	goto out;
	}

	for (i = 0; i < MAX_BUSID; i++) {
	spin_lock(&busid_table[i].busid_lock);
	if (!busid_table[i].name[0]) {
	strlcpy(busid_table[i].name, busid, BUSID_SIZE);
	if ((busid_table[i].status != STUB_BUSID_ALLOC) &&
	(busid_table[i].status != STUB_BUSID_REMOV))
	busid_table[i].status = STUB_BUSID_ADDED;
	ret = 0;
	spin_unlock(&busid_table[i].busid_lock);
	break;
	}
	spin_unlock(&busid_table[i].busid_lock);
	}

	out:
	spin_unlock(&busid_table_lock);

	return ret;
	}

	int del_match_busid(char *busid)
	{
	int idx;
	int ret = -1;

	spin_lock(&busid_table_lock);
	idx = get_busid_idx(busid);
	if (idx < 0)
	goto out;

	/* found */
	ret = 0;

	spin_lock(&busid_table[idx].busid_lock);

	if (busid_table[idx].status == STUB_BUSID_OTHER)
	memset(busid_table[idx].name, 0, BUSID_SIZE);

	if ((busid_table[idx].status != STUB_BUSID_OTHER) &&
	(busid_table[idx].status != STUB_BUSID_ADDED))
	busid_table[idx].status = STUB_BUSID_REMOV;

	spin_unlock(&busid_table[idx].busid_lock);
	out:
	spin_unlock(&busid_table_lock);

	return ret;
	}

	static ssize_t match_busid_show(struct device_driver drv, char buf)
	{
	int i;
	char *out = buf;

	spin_lock(&busid_table_lock);
	for (i = 0; i < MAX_BUSID; i++) {
	spin_lock(&busid_table[i].busid_lock);
	if (busid_table[i].name[0])
	out += sprintf(out, "%s ", busid_table[i].name);
	spin_unlock(&busid_table[i].busid_lock);
	}
	spin_unlock(&busid_table_lock);
	out += sprintf(out, "\n");

	return out - buf;
	}

	static ssize_t match_busid_store(struct device_driver dev, const char buf,
	size_t count)
	{
	int len;
	char busid[BUSID_SIZE];

	if (count < 5)
	return -EINVAL;

	/* busid needs to include \0 termination */
	len = strlcpy(busid, buf + 4, BUSID_SIZE);
	if (sizeof(busid) <= len)
	return -EINVAL;

	if (!strncmp(buf, "add ", 4)) {
	if (add_match_busid(busid) < 0)
	return -ENOMEM;

	pr_debug("add busid %s\n", busid);
	return count;
	}

	if (!strncmp(buf, "del ", 4)) {
	if (del_match_busid(busid) < 0)
	return -ENODEV;

	pr_debug("del busid %s\n", busid);
	return count;
	}

	return -EINVAL;
	}
	static DRIVER_ATTR_RW(match_busid);

	static int do_rebind(char busid, struct bus_id_priv busid_priv)
	{
	int ret;

	/* device_attach() callers should hold parent lock for USB */
	if (busid_priv->udev->dev.parent)
	device_lock(busid_priv->udev->dev.parent);
	ret = device_attach(&busid_priv->udev->dev);
	if (busid_priv->udev->dev.parent)
	device_unlock(busid_priv->udev->dev.parent);
	if (ret < 0) {
	dev_err(&busid_priv->udev->dev, "rebind failed\n");
	return ret;
	}
	return 0;
	}

	static void stub_device_rebind(void)
	{
	#if IS_MODULE(CONFIG_USBIP_HOST)
	struct bus_id_priv *busid_priv;
	int i;

	/* update status to STUB_BUSID_OTHER so probe ignores the device */
	spin_lock(&busid_table_lock);
	for (i = 0; i < MAX_BUSID; i++) {
	if (busid_table[i].name[0] &&
	busid_table[i].shutdown_busid) {
	busid_priv = &(busid_table[i]);
	busid_priv->status = STUB_BUSID_OTHER;
	}
	}
	spin_unlock(&busid_table_lock);

	/* now run rebind - no need to hold locks. driver files are removed */
	for (i = 0; i < MAX_BUSID; i++) {
	if (busid_table[i].name[0] &&
	busid_table[i].shutdown_busid) {
	busid_priv = &(busid_table[i]);
	do_rebind(busid_table[i].name, busid_priv);
	}
	}
	#endif
	}

	static ssize_t rebind_store(struct device_driver dev, const char buf,
	size_t count)
	{
	int ret;
	int len;
	struct bus_id_priv *bid;

	/* buf length should be less that BUSID_SIZE */
	len = strnlen(buf, BUSID_SIZE);

	if (!(len < BUSID_SIZE))
	return -EINVAL;

	bid = get_busid_priv(buf);
	if (!bid)
	return -ENODEV;

	/* mark the device for deletion so probe ignores it during rescan */
	bid->status = STUB_BUSID_OTHER;
	/* release the busid lock */
	put_busid_priv(bid);

	ret = do_rebind((char *) buf, bid);
	if (ret < 0)
	return ret;

	/* delete device from busid_table */
	del_match_busid((char *) buf);

	return count;
	}

	static DRIVER_ATTR_WO(rebind);

	static struct stub_priv stub_priv_pop_from_listhead(struct list_head listhead)
	{
	struct stub_priv priv, tmp;

	list_for_each_entry_safe(priv, tmp, listhead, list) {
	list_del(&priv->list);
	return priv;
	}

	return NULL;
	}

	static struct stub_priv stub_priv_pop(struct stub_device sdev)
	{
	unsigned long flags;
	struct stub_priv *priv;

	spin_lock_irqsave(&sdev->priv_lock, flags);

	priv = stub_priv_pop_from_listhead(&sdev->priv_init);
	if (priv)
	goto done;

	priv = stub_priv_pop_from_listhead(&sdev->priv_tx);
	if (priv)
	goto done;

	priv = stub_priv_pop_from_listhead(&sdev->priv_free);

	done:
	spin_unlock_irqrestore(&sdev->priv_lock, flags);

	return priv;
	}

	void stub_device_cleanup_urbs(struct stub_device *sdev)
	{
	struct stub_priv *priv;
	struct urb *urb;

	dev_dbg(&sdev->udev->dev, "Stub device cleaning up urbs\n");

	while ((priv = stub_priv_pop(sdev))) {
	urb = priv->urb;
	dev_dbg(&sdev->udev->dev, "free urb seqnum %lu\n",
	priv->seqnum);
	usb_kill_urb(urb);

	kmem_cache_free(stub_priv_cache, priv);

	kfree(urb->transfer_buffer);
	urb->transfer_buffer = NULL;

	kfree(urb->setup_packet);
	urb->setup_packet = NULL;

	usb_free_urb(urb);
	}
	}

	static int __init usbip_host_init(void)
	{
	int ret;

	init_busid_table();

	stub_priv_cache = KMEM_CACHE(stub_priv, SLAB_HWCACHE_ALIGN);
	if (!stub_priv_cache) {
	pr_err("kmem_cache_create failed\n");
	return -ENOMEM;
	}

	ret = usb_register_device_driver(&stub_driver, THIS_MODULE);
	if (ret) {
	pr_err("usb_register failed %d\n", ret);
	goto err_usb_register;
	}

	ret = driver_create_file(&stub_driver.drvwrap.driver,
	&driver_attr_match_busid);
	if (ret) {
	pr_err("driver_create_file failed\n");
	goto err_create_file;
	}

	ret = driver_create_file(&stub_driver.drvwrap.driver,
	&driver_attr_rebind);
	if (ret) {
	pr_err("driver_create_file failed\n");
	goto err_create_file;
	}

	return ret;

	err_create_file:
	usb_deregister_device_driver(&stub_driver);
	err_usb_register:
	kmem_cache_destroy(stub_priv_cache);
	return ret;
	}

	static void __exit usbip_host_exit(void)
	{
	driver_remove_file(&stub_driver.drvwrap.driver,
	&driver_attr_match_busid);

	driver_remove_file(&stub_driver.drvwrap.driver,
	&driver_attr_rebind);

	/*
	* deregister() calls stub_disconnect() for all devices. Device
	* specific data is cleared in stub_disconnect().
	*/
	usb_deregister_device_driver(&stub_driver);

	/* initiate scan to attach devices */
	stub_device_rebind();

	kmem_cache_destroy(stub_priv_cache);
	}

	module_init(usbip_host_init);
	module_exit(usbip_host_exit);

	MODULE_AUTHOR(DRIVER_AUTHOR);
	MODULE_DESCRIPTION(DRIVER_DESC);
	MODULE_LICENSE("GPL");