Commit | Line | Data |
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b2441318 | 1 | // SPDX-License-Identifier: GPL-2.0 |
1da177e4 LT |
2 | /* |
3 | * The USB Monitor, inspired by Dave Harding's USBMon. | |
4 | * | |
5 | * This is the 's' or 'stat' reader which debugs usbmon itself. | |
6 | * Note that this code blows through locks, so make sure that | |
7 | * /dbg/usbmon/0s is well protected from non-root users. | |
8 | * | |
9 | */ | |
10 | ||
11 | #include <linux/kernel.h> | |
5a0e3ad6 | 12 | #include <linux/slab.h> |
f940fcd8 | 13 | #include <linux/export.h> |
1da177e4 | 14 | #include <linux/usb.h> |
518386c7 | 15 | #include <linux/fs.h> |
7c0f6ba6 | 16 | #include <linux/uaccess.h> |
1da177e4 LT |
17 | |
18 | #include "usb_mon.h" | |
19 | ||
20 | #define STAT_BUF_SIZE 80 | |
21 | ||
22 | struct snap { | |
23 | int slen; | |
24 | char str[STAT_BUF_SIZE]; | |
25 | }; | |
26 | ||
27 | static int mon_stat_open(struct inode *inode, struct file *file) | |
28 | { | |
29 | struct mon_bus *mbus; | |
30 | struct snap *sp; | |
31 | ||
4c08ccf0 GKH |
32 | sp = kmalloc(sizeof(struct snap), GFP_KERNEL); |
33 | if (sp == NULL) | |
1da177e4 LT |
34 | return -ENOMEM; |
35 | ||
8e18e294 | 36 | mbus = inode->i_private; |
1da177e4 LT |
37 | |
38 | sp->slen = snprintf(sp->str, STAT_BUF_SIZE, | |
5b1c674d PZ |
39 | "nreaders %d events %u text_lost %u\n", |
40 | mbus->nreaders, mbus->cnt_events, mbus->cnt_text_lost); | |
1da177e4 LT |
41 | |
42 | file->private_data = sp; | |
43 | return 0; | |
44 | } | |
45 | ||
46 | static ssize_t mon_stat_read(struct file *file, char __user *buf, | |
47 | size_t nbytes, loff_t *ppos) | |
48 | { | |
49 | struct snap *sp = file->private_data; | |
1da177e4 | 50 | |
518386c7 | 51 | return simple_read_from_buffer(buf, nbytes, ppos, sp->str, sp->slen); |
1da177e4 LT |
52 | } |
53 | ||
54 | static int mon_stat_release(struct inode *inode, struct file *file) | |
55 | { | |
d4062fcb ML |
56 | struct snap *sp = file->private_data; |
57 | file->private_data = NULL; | |
58 | kfree(sp); | |
1da177e4 LT |
59 | return 0; |
60 | } | |
61 | ||
066202dd | 62 | const struct file_operations mon_fops_stat = { |
1da177e4 LT |
63 | .owner = THIS_MODULE, |
64 | .open = mon_stat_open, | |
65 | .llseek = no_llseek, | |
66 | .read = mon_stat_read, | |
67 | /* .write = mon_stat_write, */ | |
68 | /* .poll = mon_stat_poll, */ | |
55929332 | 69 | /* .unlocked_ioctl = mon_stat_ioctl, */ |
1da177e4 LT |
70 | .release = mon_stat_release, |
71 | }; |