1 files changed, 405 insertions, 0 deletions
diff --git a/drivers/usb/mon/mon_text.c b/drivers/usb/mon/mon_text.c
new file mode 100644
index 000000000000..755a4570477f
--- /dev/null
+++ b/drivers/usb/mon/mon_text.c
@@ -0,0 +1,405 @@
+/*
+ * 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
+
+/*
+ * This limit exists to prevent OOMs when the user process stops reading.
+ */
+#define EVENT_MAX  25
+
+#define PRINTF_DFL  120
+
+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 data_flag;
+	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_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 Control needs setup packet taken.
+	 * 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->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 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(struct file *file, char __user *buf,
+				size_t nbytes, loff_t *ppos)
+{
+	struct mon_reader_text *rp = file->private_data;
+	struct mon_bus *mbus = rp->r.m_bus;
+	DECLARE_WAITQUEUE(waita, current);
+	struct mon_event_text *ep;
+	int cnt, limit;
+	char *pbuf;
+	char udir, utype;
+	int data_len, i;
+
+	add_wait_queue(&rp->wait, &waita);
+	set_current_state(TASK_INTERRUPTIBLE);
+	while ((ep = mon_text_fetch(rp, mbus)) == NULL) {
+		if (file->f_flags & O_NONBLOCK) {
+			set_current_state(TASK_RUNNING);
+			remove_wait_queue(&rp->wait, &waita);
+			return -EWOULDBLOCK;	/* Same as EAGAIN in Linux */
+		}
+		/*
+		 * We do not count nwaiters, because ->release is supposed
+		 * to be called when all openers are gone only.
+		 */
+		schedule();
+		if (signal_pending(current)) {
+			remove_wait_queue(&rp->wait, &waita);
+			return -EINTR;
+		}
+		set_current_state(TASK_INTERRUPTIBLE);
+	}
+	set_current_state(TASK_RUNNING);
+	remove_wait_queue(&rp->wait, &waita);
+
+	down(&rp->printf_lock);
+	cnt = 0;
+	pbuf = rp->printf_buf;
+	limit = rp->printf_size;
+
+	udir = usb_pipein(ep->pipe) ? 'i' : 'o';
+	switch (usb_pipetype(ep->pipe)) {
+	case PIPE_ISOCHRONOUS:	utype = 'Z'; break;
+	case PIPE_INTERRUPT:	utype = 'I'; break;
+	case PIPE_CONTROL:	utype = 'C'; break;
+	default: /* PIPE_BULK */  utype = 'B';
+	}
+	cnt += snprintf(pbuf + cnt, limit - cnt,
+	    "%lx %u %c %c%c:%03u:%02u %d %d",
+	    ep->id, ep->tstamp, ep->type,
+	    utype, udir, usb_pipedevice(ep->pipe), usb_pipeendpoint(ep->pipe),
+	    ep->status, ep->length);
+
+	if ((data_len = ep->length) > 0) {
+		if (ep->data_flag == 0) {
+			cnt += snprintf(pbuf + cnt, limit - cnt, " =");
+			if (data_len >= DATA_MAX)
+				data_len = DATA_MAX;
+			for (i = 0; i < data_len; i++) {
+				if (i % 4 == 0) {
+					cnt += snprintf(pbuf + cnt, limit - cnt,
+					    " ");
+				}
+				cnt += snprintf(pbuf + cnt, limit - cnt,
+				    "%02x", ep->data[i]);
+			}
+			cnt += snprintf(pbuf + cnt, limit - cnt, "\n");
+		} else {
+			cnt += snprintf(pbuf + cnt, limit - cnt,
+			    " %c\n", ep->data_flag);
+		}
+	} else {
+		cnt += snprintf(pbuf + cnt, limit - cnt, "\n");
+	}
+
+	if (copy_to_user(buf, rp->printf_buf, cnt))
+		cnt = -EFAULT;
+	up(&rp->printf_lock);
+	kmem_cache_free(rp->e_slab, ep);
+	return cnt;
+}
+
+static int mon_text_release(struct inode *inode, struct file *file)
+{
+	struct mon_reader_text *rp = file->private_data;
+	struct mon_bus *mbus;
+	/* unsigned long flags; */
+	struct list_head *p;
+	struct mon_event_text *ep;
+
+	down(&mon_lock);
+	mbus = inode->u.generic_ip;
+
+	if (mbus->nreaders <= 0) {
+		printk(KERN_ERR TAG ": consistency error on close\n");
+		up(&mon_lock);
+		return 0;
+	}
+	mon_reader_del(mbus, &rp->r);
+
+	/*
+	 * In theory, e_list is protected by mbus->lock. However,
+	 * after mon_reader_del has finished, the following is the case:
+	 *  - we are not on reader list anymore, so new events won't be added;
+	 *  - whole mbus may be dropped if it was orphaned.
+	 * So, we better not touch mbus.
+	 */
+	/* spin_lock_irqsave(&mbus->lock, flags); */
+	while (!list_empty(&rp->e_list)) {
+		p = rp->e_list.next;
+		ep = list_entry(p, struct mon_event_text, e_link);
+		list_del(p);
+		--rp->nevents;
+		kmem_cache_free(rp->e_slab, ep);
+	}
+	/* spin_unlock_irqrestore(&mbus->lock, flags); */
+
+	kmem_cache_destroy(rp->e_slab);
+	kfree(rp->printf_buf);
+	kfree(rp);
+
+	up(&mon_lock);
+	return 0;
+}
+
+struct file_operations mon_fops_text = {
+	.owner =	THIS_MODULE,
+	.open =		mon_text_open,
+	.llseek =	no_llseek,
+	.read =		mon_text_read,
+	/* .write =	mon_text_write, */
+	/* .poll =		mon_text_poll, */
+	/* .ioctl =	mon_text_ioctl, */
+	.release =	mon_text_release,
+};
+
+/*
+ * Slab interface: constructor.
+ */
+static void mon_text_ctor(void *mem, kmem_cache_t *slab, unsigned long sflags)
+{
+	/*
+	 * Nothing to initialize. No, really!
+	 * So, we fill it with garbage to emulate a reused object.
+	 */
+	memset(mem, 0xe5, sizeof(struct mon_event_text));
+}
+
+static void mon_text_dtor(void *mem, kmem_cache_t *slab, unsigned long sflags)
+{
+	;
+}