mon_text.c | Explore in Territory

// SPDX-License-Identifier: GPL-2.0
/*
 * The USB Monitor, inspired by Dave Harding's USBMon.
 *
 * This is a text format reader.
 */

#include <linux/kernel.h>
#include <linux/list.h>
#include <linux/usb.h>
#include <linux/slab.h>
#include <linux/sched/signal.h>
#include <linux/time.h>
#include <linux/ktime.h>
#include <linux/export.h>
#include <linux/mutex.h>
#include <linux/debugfs.h>
#include <linux/scatterlist.h>
#include <linux/uaccess.h>

#include "usb_mon.h"

/*
 * No, we do not want arbitrarily long data strings.
 * Use the binary interface if you want to capture bulk data!
 */
#define DATA_MAX …

/*
 * Defined by USB 2.0 clause 9.3, table 9.2.
 */
#define SETUP_MAX …

/*
 * This limit exists to prevent OOMs when the user process stops reading.
 * If usbmon were available to unprivileged processes, it might be open
 * to a local DoS. But we have to keep to root in order to prevent
 * password sniffing from HID devices.
 */
#define EVENT_MAX …

/*
 * Potentially unlimited number; we limit it for similar allocations.
 * The usbfs limits this to 128, but we're not quite as generous.
 */
#define ISODESC_MAX …

#define PRINTF_DFL …

struct mon_iso_desc { … };

struct mon_event_text { … };

#define SLAB_NAME_SZ …
struct mon_reader_text { … };

static struct dentry *mon_dir;		/* Usually /sys/kernel/debug/usbmon */

static void mon_text_ctor(void *);

struct mon_text_ptr { … };

static struct mon_event_text *
    mon_text_read_wait(struct mon_reader_text *rp, struct file *file);
static void mon_text_read_head_t(struct mon_reader_text *rp,
	struct mon_text_ptr *p, const struct mon_event_text *ep);
static void mon_text_read_head_u(struct mon_reader_text *rp,
	struct mon_text_ptr *p, const struct mon_event_text *ep);
static void mon_text_read_statset(struct mon_reader_text *rp,
	struct mon_text_ptr *p, const struct mon_event_text *ep);
static void mon_text_read_intstat(struct mon_reader_text *rp,
	struct mon_text_ptr *p, const struct mon_event_text *ep);
static void mon_text_read_isostat(struct mon_reader_text *rp,
	struct mon_text_ptr *p, const struct mon_event_text *ep);
static void mon_text_read_isodesc(struct mon_reader_text *rp,
	struct mon_text_ptr *p, const struct mon_event_text *ep);
static void mon_text_read_data(struct mon_reader_text *rp,
    struct mon_text_ptr *p, const struct mon_event_text *ep);

/*
 * mon_text_submit
 * mon_text_complete
 *
 * May be called from an interrupt.
 *
 * This is called with the whole mon_bus locked, so no additional lock.
 */

static inline char mon_text_get_setup(struct mon_event_text *ep,
    struct urb *urb, char ev_type, struct mon_bus *mbus)
{ … }

static inline char mon_text_get_data(struct mon_event_text *ep, struct urb *urb,
    int len, char ev_type, struct mon_bus *mbus)
{ … }

static inline unsigned int mon_get_timestamp(void)
{ … }

static void mon_text_event(struct mon_reader_text *rp, struct urb *urb,
    char ev_type, int status)
{ … }

static void mon_text_submit(void *data, struct urb *urb)
{ … }

static void mon_text_complete(void *data, struct urb *urb, int status)
{ … }

static void mon_text_error(void *data, struct urb *urb, int error)
{ … }

/*
 * Fetch next event from the circular buffer.
 */
static struct mon_event_text *mon_text_fetch(struct mon_reader_text *rp,
    struct mon_bus *mbus)
{ … }

/*
 */
static int mon_text_open(struct inode *inode, struct file *file)
{ … }

static ssize_t mon_text_copy_to_user(struct mon_reader_text *rp,
    char __user * const buf, const size_t nbytes)
{ … }

/* ppos is not advanced since the llseek operation is not permitted. */
static ssize_t mon_text_read_t(struct file *file, char __user *buf,
    size_t nbytes, loff_t *ppos)
{ … }

/* ppos is not advanced since the llseek operation is not permitted. */
static ssize_t mon_text_read_u(struct file *file, char __user *buf,
    size_t nbytes, loff_t *ppos)
{ … }

static struct mon_event_text *mon_text_read_wait(struct mon_reader_text *rp,
    struct file *file)
{ … }

static void mon_text_read_head_t(struct mon_reader_text *rp,
	struct mon_text_ptr *p, const struct mon_event_text *ep)
{ … }

static void mon_text_read_head_u(struct mon_reader_text *rp,
	struct mon_text_ptr *p, const struct mon_event_text *ep)
{ … }

static void mon_text_read_statset(struct mon_reader_text *rp,
	struct mon_text_ptr *p, const struct mon_event_text *ep)
{ … }

static void mon_text_read_intstat(struct mon_reader_text *rp,
	struct mon_text_ptr *p, const struct mon_event_text *ep)
{ … }

static void mon_text_read_isostat(struct mon_reader_text *rp,
	struct mon_text_ptr *p, const struct mon_event_text *ep)
{ … }

static void mon_text_read_isodesc(struct mon_reader_text *rp,
	struct mon_text_ptr *p, const struct mon_event_text *ep)
{ … }

static void mon_text_read_data(struct mon_reader_text *rp,
    struct mon_text_ptr *p, const struct mon_event_text *ep)
{ … }

static int mon_text_release(struct inode *inode, struct file *file)
{ … }

static const struct file_operations mon_fops_text_t = …;

static const struct file_operations mon_fops_text_u = …;

int mon_text_add(struct mon_bus *mbus, const struct usb_bus *ubus)
{ … }

void mon_text_del(struct mon_bus *mbus)
{ … }

/*
 * Slab interface: constructor.
 */
static void mon_text_ctor(void *mem)
{ … }

int __init mon_text_init(void)
{ … }

void mon_text_exit(void)
{ … }
linux/drivers/usb/mon/mon_text.c
