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/*
* 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/time.h>
#include <asm/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 32
/*
* Defined by USB 2.0 clause 9.3, table 9.2.
*/
#define SETUP_MAX 8
/*
* This limit exists to prevent OOMs when the user process stops reading.
*/
#define EVENT_MAX 25
#define PRINTF_DFL 130
struct mon_event_text {
struct list_head e_link;
int type; /* submit, complete, etc. */
unsigned int pipe; /* Pipe */
unsigned long id; /* From pointer, most of the time */
unsigned int tstamp;
int length; /* Depends on type: xfer length or act length */
int status;
char setup_flag;
char data_flag;
unsigned char setup[SETUP_MAX];
unsigned char data[DATA_MAX];
};
#define SLAB_NAME_SZ 30
struct mon_reader_text {
kmem_cache_t *e_slab;
int nevents;
struct list_head e_list;
struct mon_reader r; /* In C, parent class can be placed anywhere */
wait_queue_head_t wait;
int printf_size;
char *printf_buf;
struct semaphore printf_lock;
char slab_name[SLAB_NAME_SZ];
};
static void mon_text_ctor(void *, kmem_cache_t *, unsigned long);
static void mon_text_dtor(void *, kmem_cache_t *, unsigned long);
/*
* 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)
{
if (!usb_pipecontrol(urb->pipe) || ev_type != 'S')
return '-';
if (urb->transfer_flags & URB_NO_SETUP_DMA_MAP)
return 'D';
if (urb->setup_packet == NULL)
return 'Z'; /* '0' would be not as pretty. */
memcpy(ep->setup, urb->setup_packet, SETUP_MAX);
return 0;
}
static inline char mon_text_get_data(struct mon_event_text *ep, struct urb *urb,
int len, char ev_type)
{
int pipe = urb->pipe;
unsigned char *data;
/*
* The check to see if it's safe to poke at data has an enormous
* number of corner cases, but it seems that the following is
* more or less safe.
*
* We do not even try to look transfer_buffer, because it can
* contain non-NULL garbage in case the upper level promised to
* set DMA for the HCD.
*/
if (urb->transfer_flags & URB_NO_TRANSFER_DMA_MAP)
return 'D';
if (len <= 0)
return 'L';
if ((data = urb->transfer_buffer) == NULL)
return 'Z'; /* '0' would be not as pretty. */
/*
* Bulk is easy to shortcut reliably.
* XXX Other pipe types need consideration. Currently, we overdo it
* and collect garbage for them: better more than less.
*/
if (usb_pipebulk(pipe) || usb_pipecontrol(pipe)) {
if (usb_pipein(pipe)) {
if (ev_type == 'S')
return '<';
} else {
if (ev_type == 'C')
return '>';
}
}
if (len >= DATA_MAX)
len = DATA_MAX;
memcpy(ep->data, urb->transfer_buffer, len);
return 0;
}
static inline unsigned int mon_get_timestamp(void)
{
struct timeval tval;
unsigned int stamp;
do_gettimeofday(&tval);
stamp = tval.tv_sec & 0xFFFF; /* 2^32 = 4294967296. Limit to 4096s. */
stamp = stamp * 1000000 + tval.tv_usec;
return stamp;
}
static void mon_text_event(struct mon_reader_text *rp, struct urb *urb,
char ev_type)
{
struct mon_event_text *ep;
unsigned int stamp;
stamp = mon_get_timestamp();
if (rp->nevents >= EVENT_MAX ||
(ep = kmem_cache_alloc(rp->e_slab, SLAB_ATOMIC)) == NULL) {
rp->r.m_bus->cnt_text_lost++;
return;
}
ep->type = ev_type;
ep->pipe = urb->pipe;
ep->id = (unsigned long) urb;
ep->tstamp = stamp;
ep->length = (ev_type == 'S') ?
urb->transfer_buffer_length : urb->actual_length;
/* Collecting status makes debugging sense for submits, too */
ep->status = urb->status;
ep->setup_flag = mon_text_get_setup(ep, urb, ev_type);
ep->data_flag = mon_text_get_data(ep, urb, ep->length, ev_type);
rp->nevents++;
list_add_tail(&ep->e_link, &rp->e_list);
wake_up(&rp->wait);
}
static void mon_text_submit(void *data, struct urb *urb)
{
struct mon_reader_text *rp = data;
mon_text_event(rp, urb, 'S');
}
static void mon_text_complete(void *data, struct urb *urb)
{
struct mon_reader_text *rp = data;
mon_text_event(rp, urb, 'C');
}
/*
* Fetch next event from the circular buffer.
*/
static struct mon_event_text *mon_text_fetch(struct mon_reader_text *rp,
struct mon_bus *mbus)
{
struct list_head *p;
unsigned long flags;
spin_lock_irqsave(&mbus->lock, flags);
if (list_empty(&rp->e_list)) {
spin_unlock_irqrestore(&mbus->lock, flags);
return NULL;
}
p = rp->e_list.next;
list_del(p);
--rp->nevents;
spin_unlock_irqrestore(&mbus->lock, flags);
return list_entry(p, struct mon_event_text, e_link);
}
/*
*/
static int mon_text_open(struct inode *inode, struct file *file)
{
struct mon_bus *mbus;
struct usb_bus *ubus;
struct mon_reader_text *rp;
int rc;
down(&mon_lock);
mbus = inode->u.generic_ip;
ubus = mbus->u_bus;
rp = kmalloc(sizeof(struct mon_reader_text), GFP_KERNEL);
if (rp == NULL) {
rc = -ENOMEM;
goto err_alloc;
}
memset(rp, 0, sizeof(struct mon_reader_text));
INIT_LIST_HEAD(&rp->e_list);
init_waitqueue_head(&rp->wait);
init_MUTEX(&rp->printf_lock);
rp->printf_size = PRINTF_DFL;
rp->printf_buf = kmalloc(rp->printf_size, GFP_KERNEL);
if (rp->printf_buf == NULL) {
rc = -ENOMEM;
goto err_alloc_pr;
}
rp->r.m_bus = mbus;
rp->r.r_data = rp;
rp->r.rnf_submit = mon_text_submit;
rp->r.rnf_complete = mon_text_complete;
snprintf(rp->slab_name, SLAB_NAME_SZ, "mon%dt_%lx", ubus->busnum,
(long)rp);
rp->e_slab = kmem_cache_create(rp->slab_name,
sizeof(struct mon_event_text), sizeof(long), 0,
mon_text_ctor, mon_text_dtor);
if (rp->e_slab == NULL) {
rc = -ENOMEM;
goto err_slab;
}
mon_reader_add(mbus, &rp->r);
file->private_data = rp;
up(&mon_lock);
return 0;
// err_busy:
// kmem_cache_destroy(rp->e_slab);
err_slab:
kfree(rp->printf_buf);
err_alloc_pr:
kfree(rp);
err_alloc:
up(&mon_lock);
return
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