mon_text.c

来自「omap3 linux 2.6 用nocc去除了冗余代码」· C语言 代码 · 共 744 行 · 第 1/2 页

/*
 * 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 <linux/mutex.h>
#include <linux/debugfs.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.
 * 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  (4*PAGE_SIZE / sizeof(struct mon_event_text))

/*
 * 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   5

#define PRINTF_DFL  250   /* with 5 ISOs segs */

struct mon_iso_desc {
	int status;
	unsigned int offset;
	unsigned int length;	/* Unsigned here, signed in URB. Historic. */
};

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 busnum;
	int length;		/* Depends on type: xfer length or act length */
	int status;
	int interval;
	int start_frame;
	int error_count;
	char setup_flag;
	char data_flag;
	int numdesc;		/* Full number */
	struct mon_iso_desc isodesc[ISODESC_MAX];
	unsigned char setup[SETUP_MAX];
	unsigned char data[DATA_MAX];
};

#define SLAB_NAME_SZ  30
struct mon_reader_text {
	struct kmem_cache *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 mutex printf_lock;

	char slab_name[SLAB_NAME_SZ];
};

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

static void mon_text_ctor(void *, struct kmem_cache *, unsigned long);

struct mon_text_ptr {
	int cnt, limit;
	char *pbuf;
};

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)
{

	if (!usb_pipecontrol(urb->pipe) || ev_type != 'S')
		return '-';

	if (urb->dev->bus->uses_dma &&
	    (urb->transfer_flags & URB_NO_SETUP_DMA_MAP)) {
		return mon_dmapeek(ep->setup, urb->setup_dma, SETUP_MAX);
	}
	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, struct mon_bus *mbus)
{
	int pipe = urb->pipe;

	if (len <= 0)
		return 'L';
	if (len >= DATA_MAX)
		len = DATA_MAX;

	if (usb_pipein(pipe)) {
		if (ev_type != 'C')
			return '<';
	} else {
		if (ev_type != 'S')
			return '>';
	}

	/*
	 * 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 at transfer_buffer, because it can
	 * contain non-NULL garbage in case the upper level promised to
	 * set DMA for the HCD.
	 */
	if (urb->dev->bus->uses_dma &&
	    (urb->transfer_flags & URB_NO_TRANSFER_DMA_MAP)) {
		return mon_dmapeek(ep->data, urb->transfer_dma, len);
	}

	if (urb->transfer_buffer == NULL)
		return 'Z';	/* '0' would be not as pretty. */

	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;
	struct usb_iso_packet_descriptor *fp;
	struct mon_iso_desc *dp;
	int i, ndesc;

	stamp = mon_get_timestamp();

	if (rp->nevents >= EVENT_MAX ||
	    (ep = kmem_cache_alloc(rp->e_slab, GFP_ATOMIC)) == NULL) {
		rp->r.m_bus->cnt_text_lost++;
		return;
	}

	ep->type = ev_type;
	ep->pipe = urb->pipe;
	ep->id = (unsigned long) urb;
	ep->busnum = urb->dev->bus->busnum;
	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;

	if (usb_pipeint(urb->pipe)) {
		ep->interval = urb->interval;
	} else if (usb_pipeisoc(urb->pipe)) {
		ep->interval = urb->interval;
		ep->start_frame = urb->start_frame;
		ep->error_count = urb->error_count;
	}
	ep->numdesc = urb->number_of_packets;
	if (usb_pipeisoc(urb->pipe) && urb->number_of_packets > 0) {
		if ((ndesc = urb->number_of_packets) > ISODESC_MAX)
			ndesc = ISODESC_MAX;
		fp = urb->iso_frame_desc;
		dp = ep->isodesc;
		for (i = 0; i < ndesc; i++) {
			dp->status = fp->status;
			dp->offset = fp->offset;
			dp->length = (ev_type == 'S') ?
			    fp->length : fp->actual_length;
			fp++;
			dp++;
		}
	}

	ep->setup_flag = mon_text_get_setup(ep, urb, ev_type, rp->r.m_bus);
	ep->data_flag = mon_text_get_data(ep, urb, ep->length, ev_type,
			rp->r.m_bus);

	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');
}

static void mon_text_error(void *data, struct urb *urb, int error)
{
	struct mon_reader_text *rp = data;
	struct mon_event_text *ep;

	if (rp->nevents >= EVENT_MAX ||
	    (ep = kmem_cache_alloc(rp->e_slab, GFP_ATOMIC)) == NULL) {
		rp->r.m_bus->cnt_text_lost++;
		return;
	}

	ep->type = 'E';
	ep->pipe = urb->pipe;
	ep->id = (unsigned long) urb;
	ep->busnum = 0;
	ep->tstamp = 0;
	ep->length = 0;
	ep->status = error;

	ep->setup_flag = '-';
	ep->data_flag = 'E';

	rp->nevents++;
	list_add_tail(&ep->e_link, &rp->e_list);
	wake_up(&rp->wait);
}

/*
 * 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 mon_reader_text *rp;
	int rc;

	mutex_lock(&mon_lock);
	mbus = inode->i_private;

	rp = kzalloc(sizeof(struct mon_reader_text), GFP_KERNEL);
	if (rp == NULL) {
		rc = -ENOMEM;
		goto err_alloc;
	}
	INIT_LIST_HEAD(&rp->e_list);
	init_waitqueue_head(&rp->wait);
	mutex_init(&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_error = mon_text_error;
	rp->r.rnf_complete = mon_text_complete;

	snprintf(rp->slab_name, SLAB_NAME_SZ, "mon_text_%p", rp);
	rp->e_slab = kmem_cache_create(rp->slab_name,
	    sizeof(struct mon_event_text), sizeof(long), 0,
	    mon_text_ctor, NULL);
	if (rp->e_slab == NULL) {
		rc = -ENOMEM;
		goto err_slab;
	}

	mon_reader_add(mbus, &rp->r);

	file->private_data = rp;
	mutex_unlock(&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:
	mutex_unlock(&mon_lock);
	return rc;
}

/*
 * For simplicity, we read one record in one system call and throw out
 * what does not fit. This means that the following does not work:
 *   dd if=/dbg/usbmon/0t bs=10
 * Also, we do not allow seeks and do not bother advancing the offset.
 */
static ssize_t mon_text_read_t(struct file *file, char __user *buf,