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