406 строки
9.6 KiB
C
406 строки
9.6 KiB
C
/*
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* The USB Monitor, inspired by Dave Harding's USBMon.
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*
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* This is a text format reader.
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*/
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#include <linux/kernel.h>
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#include <linux/list.h>
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#include <linux/usb.h>
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#include <linux/time.h>
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#include <asm/uaccess.h>
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#include "usb_mon.h"
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/*
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* No, we do not want arbitrarily long data strings.
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* Use the binary interface if you want to capture bulk data!
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*/
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#define DATA_MAX 32
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/*
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* This limit exists to prevent OOMs when the user process stops reading.
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*/
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#define EVENT_MAX 25
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#define PRINTF_DFL 120
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struct mon_event_text {
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struct list_head e_link;
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int type; /* submit, complete, etc. */
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unsigned int pipe; /* Pipe */
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unsigned long id; /* From pointer, most of the time */
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unsigned int tstamp;
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int length; /* Depends on type: xfer length or act length */
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int status;
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char data_flag;
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unsigned char data[DATA_MAX];
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};
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#define SLAB_NAME_SZ 30
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struct mon_reader_text {
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kmem_cache_t *e_slab;
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int nevents;
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struct list_head e_list;
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struct mon_reader r; /* In C, parent class can be placed anywhere */
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wait_queue_head_t wait;
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int printf_size;
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char *printf_buf;
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struct semaphore printf_lock;
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char slab_name[SLAB_NAME_SZ];
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};
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static void mon_text_ctor(void *, kmem_cache_t *, unsigned long);
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static void mon_text_dtor(void *, kmem_cache_t *, unsigned long);
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/*
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* mon_text_submit
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* mon_text_complete
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*
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* May be called from an interrupt.
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*
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* This is called with the whole mon_bus locked, so no additional lock.
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*/
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static inline char mon_text_get_data(struct mon_event_text *ep, struct urb *urb,
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int len, char ev_type)
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{
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int pipe = urb->pipe;
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unsigned char *data;
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/*
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* The check to see if it's safe to poke at data has an enormous
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* number of corner cases, but it seems that the following is
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* more or less safe.
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*
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* We do not even try to look transfer_buffer, because it can
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* contain non-NULL garbage in case the upper level promised to
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* set DMA for the HCD.
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*/
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if (urb->transfer_flags & URB_NO_TRANSFER_DMA_MAP)
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return 'D';
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if (len <= 0)
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return 'L';
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if ((data = urb->transfer_buffer) == NULL)
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return 'Z'; /* '0' would be not as pretty. */
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/*
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* Bulk is easy to shortcut reliably.
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* XXX Control needs setup packet taken.
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* XXX Other pipe types need consideration. Currently, we overdo it
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* and collect garbage for them: better more than less.
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*/
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if (usb_pipebulk(pipe) || usb_pipecontrol(pipe)) {
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if (usb_pipein(pipe)) {
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if (ev_type == 'S')
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return '<';
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} else {
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if (ev_type == 'C')
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return '>';
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}
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}
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if (len >= DATA_MAX)
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len = DATA_MAX;
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memcpy(ep->data, urb->transfer_buffer, len);
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return 0;
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}
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static inline unsigned int mon_get_timestamp(void)
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{
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struct timeval tval;
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unsigned int stamp;
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do_gettimeofday(&tval);
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stamp = tval.tv_sec & 0xFFFF; /* 2^32 = 4294967296. Limit to 4096s. */
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stamp = stamp * 1000000 + tval.tv_usec;
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return stamp;
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}
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static void mon_text_event(struct mon_reader_text *rp, struct urb *urb,
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char ev_type)
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{
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struct mon_event_text *ep;
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unsigned int stamp;
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stamp = mon_get_timestamp();
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if (rp->nevents >= EVENT_MAX ||
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(ep = kmem_cache_alloc(rp->e_slab, SLAB_ATOMIC)) == NULL) {
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rp->r.m_bus->cnt_text_lost++;
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return;
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}
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ep->type = ev_type;
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ep->pipe = urb->pipe;
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ep->id = (unsigned long) urb;
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ep->tstamp = stamp;
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ep->length = (ev_type == 'S') ?
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urb->transfer_buffer_length : urb->actual_length;
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/* Collecting status makes debugging sense for submits, too */
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ep->status = urb->status;
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ep->data_flag = mon_text_get_data(ep, urb, ep->length, ev_type);
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rp->nevents++;
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list_add_tail(&ep->e_link, &rp->e_list);
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wake_up(&rp->wait);
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}
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static void mon_text_submit(void *data, struct urb *urb)
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{
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struct mon_reader_text *rp = data;
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mon_text_event(rp, urb, 'S');
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}
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static void mon_text_complete(void *data, struct urb *urb)
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{
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struct mon_reader_text *rp = data;
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mon_text_event(rp, urb, 'C');
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}
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/*
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* Fetch next event from the circular buffer.
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*/
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static struct mon_event_text *mon_text_fetch(struct mon_reader_text *rp,
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struct mon_bus *mbus)
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{
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struct list_head *p;
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unsigned long flags;
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spin_lock_irqsave(&mbus->lock, flags);
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if (list_empty(&rp->e_list)) {
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spin_unlock_irqrestore(&mbus->lock, flags);
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return NULL;
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}
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p = rp->e_list.next;
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list_del(p);
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--rp->nevents;
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spin_unlock_irqrestore(&mbus->lock, flags);
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return list_entry(p, struct mon_event_text, e_link);
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}
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/*
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*/
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static int mon_text_open(struct inode *inode, struct file *file)
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{
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struct mon_bus *mbus;
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struct usb_bus *ubus;
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struct mon_reader_text *rp;
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int rc;
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down(&mon_lock);
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mbus = inode->u.generic_ip;
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ubus = mbus->u_bus;
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rp = kmalloc(sizeof(struct mon_reader_text), GFP_KERNEL);
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if (rp == NULL) {
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rc = -ENOMEM;
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goto err_alloc;
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}
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memset(rp, 0, sizeof(struct mon_reader_text));
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INIT_LIST_HEAD(&rp->e_list);
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init_waitqueue_head(&rp->wait);
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init_MUTEX(&rp->printf_lock);
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rp->printf_size = PRINTF_DFL;
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rp->printf_buf = kmalloc(rp->printf_size, GFP_KERNEL);
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if (rp->printf_buf == NULL) {
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rc = -ENOMEM;
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goto err_alloc_pr;
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}
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rp->r.m_bus = mbus;
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rp->r.r_data = rp;
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rp->r.rnf_submit = mon_text_submit;
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rp->r.rnf_complete = mon_text_complete;
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snprintf(rp->slab_name, SLAB_NAME_SZ, "mon%dt_%lx", ubus->busnum,
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(long)rp);
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rp->e_slab = kmem_cache_create(rp->slab_name,
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sizeof(struct mon_event_text), sizeof(long), 0,
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mon_text_ctor, mon_text_dtor);
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if (rp->e_slab == NULL) {
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rc = -ENOMEM;
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goto err_slab;
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}
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mon_reader_add(mbus, &rp->r);
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file->private_data = rp;
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up(&mon_lock);
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return 0;
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// err_busy:
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// kmem_cache_destroy(rp->e_slab);
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err_slab:
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kfree(rp->printf_buf);
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err_alloc_pr:
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kfree(rp);
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err_alloc:
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up(&mon_lock);
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return rc;
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}
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/*
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* For simplicity, we read one record in one system call and throw out
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* what does not fit. This means that the following does not work:
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* dd if=/dbg/usbmon/0t bs=10
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* Also, we do not allow seeks and do not bother advancing the offset.
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*/
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static ssize_t mon_text_read(struct file *file, char __user *buf,
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size_t nbytes, loff_t *ppos)
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{
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struct mon_reader_text *rp = file->private_data;
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struct mon_bus *mbus = rp->r.m_bus;
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DECLARE_WAITQUEUE(waita, current);
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struct mon_event_text *ep;
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int cnt, limit;
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char *pbuf;
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char udir, utype;
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int data_len, i;
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add_wait_queue(&rp->wait, &waita);
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set_current_state(TASK_INTERRUPTIBLE);
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while ((ep = mon_text_fetch(rp, mbus)) == NULL) {
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if (file->f_flags & O_NONBLOCK) {
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set_current_state(TASK_RUNNING);
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remove_wait_queue(&rp->wait, &waita);
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return -EWOULDBLOCK; /* Same as EAGAIN in Linux */
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}
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/*
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* We do not count nwaiters, because ->release is supposed
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* to be called when all openers are gone only.
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*/
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schedule();
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if (signal_pending(current)) {
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remove_wait_queue(&rp->wait, &waita);
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return -EINTR;
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}
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set_current_state(TASK_INTERRUPTIBLE);
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}
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set_current_state(TASK_RUNNING);
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remove_wait_queue(&rp->wait, &waita);
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down(&rp->printf_lock);
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cnt = 0;
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pbuf = rp->printf_buf;
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limit = rp->printf_size;
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udir = usb_pipein(ep->pipe) ? 'i' : 'o';
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switch (usb_pipetype(ep->pipe)) {
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case PIPE_ISOCHRONOUS: utype = 'Z'; break;
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case PIPE_INTERRUPT: utype = 'I'; break;
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case PIPE_CONTROL: utype = 'C'; break;
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default: /* PIPE_BULK */ utype = 'B';
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}
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cnt += snprintf(pbuf + cnt, limit - cnt,
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"%lx %u %c %c%c:%03u:%02u %d %d",
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ep->id, ep->tstamp, ep->type,
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utype, udir, usb_pipedevice(ep->pipe), usb_pipeendpoint(ep->pipe),
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ep->status, ep->length);
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if ((data_len = ep->length) > 0) {
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if (ep->data_flag == 0) {
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cnt += snprintf(pbuf + cnt, limit - cnt, " =");
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if (data_len >= DATA_MAX)
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data_len = DATA_MAX;
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for (i = 0; i < data_len; i++) {
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if (i % 4 == 0) {
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cnt += snprintf(pbuf + cnt, limit - cnt,
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" ");
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}
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cnt += snprintf(pbuf + cnt, limit - cnt,
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"%02x", ep->data[i]);
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}
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cnt += snprintf(pbuf + cnt, limit - cnt, "\n");
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} else {
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cnt += snprintf(pbuf + cnt, limit - cnt,
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" %c\n", ep->data_flag);
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}
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} else {
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cnt += snprintf(pbuf + cnt, limit - cnt, "\n");
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}
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if (copy_to_user(buf, rp->printf_buf, cnt))
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cnt = -EFAULT;
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up(&rp->printf_lock);
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kmem_cache_free(rp->e_slab, ep);
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return cnt;
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}
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static int mon_text_release(struct inode *inode, struct file *file)
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{
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struct mon_reader_text *rp = file->private_data;
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struct mon_bus *mbus;
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/* unsigned long flags; */
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struct list_head *p;
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struct mon_event_text *ep;
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down(&mon_lock);
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mbus = inode->u.generic_ip;
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if (mbus->nreaders <= 0) {
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printk(KERN_ERR TAG ": consistency error on close\n");
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up(&mon_lock);
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return 0;
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}
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mon_reader_del(mbus, &rp->r);
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/*
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* In theory, e_list is protected by mbus->lock. However,
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* after mon_reader_del has finished, the following is the case:
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* - we are not on reader list anymore, so new events won't be added;
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* - whole mbus may be dropped if it was orphaned.
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* So, we better not touch mbus.
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*/
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/* spin_lock_irqsave(&mbus->lock, flags); */
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while (!list_empty(&rp->e_list)) {
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p = rp->e_list.next;
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ep = list_entry(p, struct mon_event_text, e_link);
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list_del(p);
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--rp->nevents;
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kmem_cache_free(rp->e_slab, ep);
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}
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/* spin_unlock_irqrestore(&mbus->lock, flags); */
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kmem_cache_destroy(rp->e_slab);
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kfree(rp->printf_buf);
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kfree(rp);
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up(&mon_lock);
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return 0;
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}
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struct file_operations mon_fops_text = {
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.owner = THIS_MODULE,
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.open = mon_text_open,
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.llseek = no_llseek,
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.read = mon_text_read,
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/* .write = mon_text_write, */
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/* .poll = mon_text_poll, */
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/* .ioctl = mon_text_ioctl, */
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.release = mon_text_release,
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};
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/*
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* Slab interface: constructor.
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*/
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static void mon_text_ctor(void *mem, kmem_cache_t *slab, unsigned long sflags)
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{
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/*
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* Nothing to initialize. No, really!
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* So, we fill it with garbage to emulate a reused object.
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*/
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memset(mem, 0xe5, sizeof(struct mon_event_text));
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}
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static void mon_text_dtor(void *mem, kmem_cache_t *slab, unsigned long sflags)
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{
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;
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}
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