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71 lines
1.6 KiB
71 lines
1.6 KiB
// SPDX-License-Identifier: GPL-2.0 |
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/* |
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* The USB Monitor, inspired by Dave Harding's USBMon. |
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* |
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* This is the 's' or 'stat' reader which debugs usbmon itself. |
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* Note that this code blows through locks, so make sure that |
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* /dbg/usbmon/0s is well protected from non-root users. |
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* |
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*/ |
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#include <linux/kernel.h> |
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#include <linux/slab.h> |
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#include <linux/export.h> |
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#include <linux/usb.h> |
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#include <linux/fs.h> |
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#include <linux/uaccess.h> |
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#include "usb_mon.h" |
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#define STAT_BUF_SIZE 80 |
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struct snap { |
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int slen; |
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char str[STAT_BUF_SIZE]; |
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}; |
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static int mon_stat_open(struct inode *inode, struct file *file) |
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{ |
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struct mon_bus *mbus; |
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struct snap *sp; |
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sp = kmalloc(sizeof(struct snap), GFP_KERNEL); |
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if (sp == NULL) |
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return -ENOMEM; |
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mbus = inode->i_private; |
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sp->slen = snprintf(sp->str, STAT_BUF_SIZE, |
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"nreaders %d events %u text_lost %u\n", |
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mbus->nreaders, mbus->cnt_events, mbus->cnt_text_lost); |
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file->private_data = sp; |
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return 0; |
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} |
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static ssize_t mon_stat_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 snap *sp = file->private_data; |
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return simple_read_from_buffer(buf, nbytes, ppos, sp->str, sp->slen); |
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} |
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static int mon_stat_release(struct inode *inode, struct file *file) |
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{ |
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struct snap *sp = file->private_data; |
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file->private_data = NULL; |
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kfree(sp); |
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return 0; |
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} |
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const struct file_operations mon_fops_stat = { |
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.owner = THIS_MODULE, |
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.open = mon_stat_open, |
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.llseek = no_llseek, |
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.read = mon_stat_read, |
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/* .write = mon_stat_write, */ |
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/* .poll = mon_stat_poll, */ |
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/* .unlocked_ioctl = mon_stat_ioctl, */ |
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.release = mon_stat_release, |
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};
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