Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * The USB Monitor, inspired by Dave Harding's USBMon. | |
3 | * | |
4 | * This is the 's' or 'stat' reader which debugs usbmon itself. | |
5 | * Note that this code blows through locks, so make sure that | |
6 | * /dbg/usbmon/0s is well protected from non-root users. | |
7 | * | |
8 | */ | |
9 | ||
10 | #include <linux/kernel.h> | |
11 | #include <linux/usb.h> | |
12 | #include <asm/uaccess.h> | |
13 | ||
14 | #include "usb_mon.h" | |
15 | ||
16 | #define STAT_BUF_SIZE 80 | |
17 | ||
18 | struct snap { | |
19 | int slen; | |
20 | char str[STAT_BUF_SIZE]; | |
21 | }; | |
22 | ||
23 | static int mon_stat_open(struct inode *inode, struct file *file) | |
24 | { | |
25 | struct mon_bus *mbus; | |
26 | struct snap *sp; | |
27 | ||
28 | if ((sp = kmalloc(sizeof(struct snap), GFP_KERNEL)) == NULL) | |
29 | return -ENOMEM; | |
30 | ||
8e18e294 | 31 | mbus = inode->i_private; |
1da177e4 LT |
32 | |
33 | sp->slen = snprintf(sp->str, STAT_BUF_SIZE, | |
5b1c674d PZ |
34 | "nreaders %d events %u text_lost %u\n", |
35 | mbus->nreaders, mbus->cnt_events, mbus->cnt_text_lost); | |
1da177e4 LT |
36 | |
37 | file->private_data = sp; | |
38 | return 0; | |
39 | } | |
40 | ||
41 | static ssize_t mon_stat_read(struct file *file, char __user *buf, | |
42 | size_t nbytes, loff_t *ppos) | |
43 | { | |
44 | struct snap *sp = file->private_data; | |
45 | loff_t pos = *ppos; | |
46 | int cnt; | |
47 | ||
48 | if (pos < 0 || pos >= sp->slen) | |
49 | return 0; | |
50 | if (nbytes == 0) | |
51 | return 0; | |
52 | if ((cnt = sp->slen - pos) > nbytes) | |
53 | cnt = nbytes; | |
54 | if (copy_to_user(buf, sp->str + pos, cnt)) | |
55 | return -EFAULT; | |
56 | *ppos = pos + cnt; | |
57 | return cnt; | |
58 | } | |
59 | ||
60 | static int mon_stat_release(struct inode *inode, struct file *file) | |
61 | { | |
62 | return 0; | |
63 | } | |
64 | ||
066202dd | 65 | const struct file_operations mon_fops_stat = { |
1da177e4 LT |
66 | .owner = THIS_MODULE, |
67 | .open = mon_stat_open, | |
68 | .llseek = no_llseek, | |
69 | .read = mon_stat_read, | |
70 | /* .write = mon_stat_write, */ | |
71 | /* .poll = mon_stat_poll, */ | |
72 | /* .ioctl = mon_stat_ioctl, */ | |
73 | .release = mon_stat_release, | |
74 | }; |