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linux/drivers/usb/serial/usb-serial.h
Luiz Fernando Capitulino 8a4613f01f [PATCH] USB: usbserial: race-condition fix. 
There is a race-condition in usb-serial driver that can be triggered if
a processes does 'port->tty->driver_data = NULL' in serial_close() while
other processes is in kernel-space about to call serial_ioctl() on the
same port.

This happens because a process can open the device while there is
another one closing it.

The patch below fixes that by adding a semaphore to ensure that no
process will open the device while another process is closing it.

Note that we can't use spinlocks here, since serial_open() and
serial_close() can sleep.

Signed-off-by: Luiz Capitulino <lcapitulino@mandriva.com.br>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2006-01-04 13:48:35 -08:00

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/*
* USB Serial Converter driver
*
* Copyright (C) 1999 - 2005
* Greg Kroah-Hartman (greg@kroah.com)
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License.
*
*/
#ifndef __LINUX_USB_SERIAL_H
#define __LINUX_USB_SERIAL_H
#include <linux/config.h>
#include <linux/kref.h>
#include <asm/semaphore.h>
#define SERIAL_TTY_MAJOR 188 /* Nice legal number now */
#define SERIAL_TTY_MINORS 255 /* loads of devices :) */
#define MAX_NUM_PORTS 8 /* The maximum number of ports one device can grab at once */
/* parity check flag */
#define RELEVANT_IFLAG(iflag) (iflag & (IGNBRK|BRKINT|IGNPAR|PARMRK|INPCK))
/**
* usb_serial_port: structure for the specific ports of a device.
* @serial: pointer back to the struct usb_serial owner of this port.
* @tty: pointer to the corresponding tty for this port.
* @lock: spinlock to grab when updating portions of this structure.
* @sem: semaphore used to synchronize serial_open() and serial_close()
* access for this port.
* @number: the number of the port (the minor number).
* @interrupt_in_buffer: pointer to the interrupt in buffer for this port.
* @interrupt_in_urb: pointer to the interrupt in struct urb for this port.
* @interrupt_in_endpointAddress: endpoint address for the interrupt in pipe
* for this port.
* @interrupt_out_buffer: pointer to the interrupt out buffer for this port.
* @interrupt_out_size: the size of the interrupt_out_buffer, in bytes.
* @interrupt_out_urb: pointer to the interrupt out struct urb for this port.
* @interrupt_out_endpointAddress: endpoint address for the interrupt out pipe
* for this port.
* @bulk_in_buffer: pointer to the bulk in buffer for this port.
* @read_urb: pointer to the bulk in struct urb for this port.
* @bulk_in_endpointAddress: endpoint address for the bulk in pipe for this
* port.
* @bulk_out_buffer: pointer to the bulk out buffer for this port.
* @bulk_out_size: the size of the bulk_out_buffer, in bytes.
* @write_urb: pointer to the bulk out struct urb for this port.
* @bulk_out_endpointAddress: endpoint address for the bulk out pipe for this
* port.
* @write_wait: a wait_queue_head_t used by the port.
* @work: work queue entry for the line discipline waking up.
* @open_count: number of times this port has been opened.
*
* This structure is used by the usb-serial core and drivers for the specific
* ports of a device.
*/
struct usb_serial_port {
struct usb_serial * serial;
struct tty_struct * tty;
spinlock_t lock;
struct semaphore sem;
unsigned char number;
unsigned char * interrupt_in_buffer;
struct urb * interrupt_in_urb;
__u8 interrupt_in_endpointAddress;
unsigned char * interrupt_out_buffer;
int interrupt_out_size;
struct urb * interrupt_out_urb;
__u8 interrupt_out_endpointAddress;
unsigned char * bulk_in_buffer;
int bulk_in_size;
struct urb * read_urb;
__u8 bulk_in_endpointAddress;
unsigned char * bulk_out_buffer;
int bulk_out_size;
struct urb * write_urb;
int write_urb_busy;
__u8 bulk_out_endpointAddress;
wait_queue_head_t write_wait;
struct work_struct work;
int open_count;
struct device dev;
};
#define to_usb_serial_port(d) container_of(d, struct usb_serial_port, dev)
/* get and set the port private data pointer helper functions */
static inline void *usb_get_serial_port_data (struct usb_serial_port *port)
{
return dev_get_drvdata(&port->dev);
}
static inline void usb_set_serial_port_data (struct usb_serial_port *port, void *data)
{
dev_set_drvdata(&port->dev, data);
}
/**
* usb_serial - structure used by the usb-serial core for a device
* @dev: pointer to the struct usb_device for this device
* @type: pointer to the struct usb_serial_driver for this device
* @interface: pointer to the struct usb_interface for this device
* @minor: the starting minor number for this device
* @num_ports: the number of ports this device has
* @num_interrupt_in: number of interrupt in endpoints we have
* @num_interrupt_out: number of interrupt out endpoints we have
* @num_bulk_in: number of bulk in endpoints we have
* @num_bulk_out: number of bulk out endpoints we have
* @port: array of struct usb_serial_port structures for the different ports.
* @private: place to put any driver specific information that is needed. The
* usb-serial driver is required to manage this data, the usb-serial core
* will not touch this. Use usb_get_serial_data() and
* usb_set_serial_data() to access this.
*/
struct usb_serial {
struct usb_device * dev;
struct usb_serial_driver * type;
struct usb_interface * interface;
unsigned char minor;
unsigned char num_ports;
unsigned char num_port_pointers;
char num_interrupt_in;
char num_interrupt_out;
char num_bulk_in;
char num_bulk_out;
struct usb_serial_port * port[MAX_NUM_PORTS];
struct kref kref;
void * private;
};
#define to_usb_serial(d) container_of(d, struct usb_serial, kref)
#define NUM_DONT_CARE (-1)
/* get and set the serial private data pointer helper functions */
static inline void *usb_get_serial_data (struct usb_serial *serial)
{
return serial->private;
}
static inline void usb_set_serial_data (struct usb_serial *serial, void *data)
{
serial->private = data;
}
/**
* usb_serial_driver - describes a usb serial driver
* @description: pointer to a string that describes this driver. This string used
* in the syslog messages when a device is inserted or removed.
* @id_table: pointer to a list of usb_device_id structures that define all
* of the devices this structure can support.
* @num_interrupt_in: the number of interrupt in endpoints this device will
* have.
* @num_interrupt_out: the number of interrupt out endpoints this device will
* have.
* @num_bulk_in: the number of bulk in endpoints this device will have.
* @num_bulk_out: the number of bulk out endpoints this device will have.
* @num_ports: the number of different ports this device will have.
* @calc_num_ports: pointer to a function to determine how many ports this
* device has dynamically. It will be called after the probe()
* callback is called, but before attach()
* @probe: pointer to the driver's probe function.
* This will be called when the device is inserted into the system,
* but before the device has been fully initialized by the usb_serial
* subsystem. Use this function to download any firmware to the device,
* or any other early initialization that might be needed.
* Return 0 to continue on with the initialization sequence. Anything
* else will abort it.
* @attach: pointer to the driver's attach function.
* This will be called when the struct usb_serial structure is fully set
* set up. Do any local initialization of the device, or any private
* memory structure allocation at this point in time.
* @shutdown: pointer to the driver's shutdown function. This will be
* called when the device is removed from the system.
*
* This structure is defines a USB Serial driver. It provides all of
* the information that the USB serial core code needs. If the function
* pointers are defined, then the USB serial core code will call them when
* the corresponding tty port functions are called. If they are not
* called, the generic serial function will be used instead.
*
* The driver.owner field should be set to the module owner of this driver.
* The driver.name field should be set to the name of this driver (remember
* it will show up in sysfs, so it needs to be short and to the point.
* Useing the module name is a good idea.)
*/
struct usb_serial_driver {
const char *description;
const struct usb_device_id *id_table;
char num_interrupt_in;
char num_interrupt_out;
char num_bulk_in;
char num_bulk_out;
char num_ports;
struct list_head driver_list;
struct device_driver driver;
int (*probe) (struct usb_serial *serial, const struct usb_device_id *id);
int (*attach) (struct usb_serial *serial);
int (*calc_num_ports) (struct usb_serial *serial);
void (*shutdown) (struct usb_serial *serial);
int (*port_probe) (struct usb_serial_port *port);
int (*port_remove) (struct usb_serial_port *port);
/* serial function calls */
int (*open) (struct usb_serial_port *port, struct file * filp);
void (*close) (struct usb_serial_port *port, struct file * filp);
int (*write) (struct usb_serial_port *port, const unsigned char *buf, int count);
int (*write_room) (struct usb_serial_port *port);
int (*ioctl) (struct usb_serial_port *port, struct file * file, unsigned int cmd, unsigned long arg);
void (*set_termios) (struct usb_serial_port *port, struct termios * old);
void (*break_ctl) (struct usb_serial_port *port, int break_state);
int (*chars_in_buffer) (struct usb_serial_port *port);
void (*throttle) (struct usb_serial_port *port);
void (*unthrottle) (struct usb_serial_port *port);
int (*tiocmget) (struct usb_serial_port *port, struct file *file);
int (*tiocmset) (struct usb_serial_port *port, struct file *file, unsigned int set, unsigned int clear);
void (*read_int_callback)(struct urb *urb, struct pt_regs *regs);
void (*write_int_callback)(struct urb *urb, struct pt_regs *regs);
void (*read_bulk_callback)(struct urb *urb, struct pt_regs *regs);
void (*write_bulk_callback)(struct urb *urb, struct pt_regs *regs);
};
#define to_usb_serial_driver(d) container_of(d, struct usb_serial_driver, driver)
extern int usb_serial_register(struct usb_serial_driver *driver);
extern void usb_serial_deregister(struct usb_serial_driver *driver);
extern void usb_serial_port_softint(void *private);
extern int usb_serial_probe(struct usb_interface *iface, const struct usb_device_id *id);
extern void usb_serial_disconnect(struct usb_interface *iface);
extern int ezusb_writememory (struct usb_serial *serial, int address, unsigned char *data, int length, __u8 bRequest);
extern int ezusb_set_reset (struct usb_serial *serial, unsigned char reset_bit);
/* USB Serial console functions */
#ifdef CONFIG_USB_SERIAL_CONSOLE
extern void usb_serial_console_init (int debug, int minor);
extern void usb_serial_console_exit (void);
#else
static inline void usb_serial_console_init (int debug, int minor) { }
static inline void usb_serial_console_exit (void) { }
#endif
/* Functions needed by other parts of the usbserial core */
extern struct usb_serial *usb_serial_get_by_index (unsigned int minor);
extern int usb_serial_generic_open (struct usb_serial_port *port, struct file *filp);
extern int usb_serial_generic_write (struct usb_serial_port *port, const unsigned char *buf, int count);
extern void usb_serial_generic_close (struct usb_serial_port *port, struct file *filp);
extern int usb_serial_generic_write_room (struct usb_serial_port *port);
extern int usb_serial_generic_chars_in_buffer (struct usb_serial_port *port);
extern void usb_serial_generic_read_bulk_callback (struct urb *urb, struct pt_regs *regs);
extern void usb_serial_generic_write_bulk_callback (struct urb *urb, struct pt_regs *regs);
extern void usb_serial_generic_shutdown (struct usb_serial *serial);
extern int usb_serial_generic_register (int debug);
extern void usb_serial_generic_deregister (void);
extern int usb_serial_bus_register (struct usb_serial_driver *device);
extern void usb_serial_bus_deregister (struct usb_serial_driver *device);
extern struct usb_serial_driver usb_serial_generic_device;
extern struct bus_type usb_serial_bus_type;
extern struct tty_driver *usb_serial_tty_driver;
static inline void usb_serial_debug_data(int debug,
struct device *dev,
const char *function, int size,
const unsigned char *data)
{
int i;
if (debug) {
dev_printk(KERN_DEBUG, dev, "%s - length = %d, data = ", function, size);
for (i = 0; i < size; ++i)
printk ("%.2x ", data[i]);
printk ("\n");
}
}
/* Use our own dbg macro */
#undef dbg
#define dbg(format, arg...) do { if (debug) printk(KERN_DEBUG "%s: " format "\n" , __FILE__ , ## arg); } while (0)
#endif /* ifdef __LINUX_USB_SERIAL_H */
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