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 <linux/fs.h> 13 #include <asm/uaccess.h> 14 15 #include "usb_mon.h" 16 17 #define STAT_BUF_SIZE 80 18 19 struct snap { 20 int slen; 21 char str[STAT_BUF_SIZE]; 22 }; 23 24 static int mon_stat_open(struct inode *inode, struct file *file) 25 { 26 struct mon_bus *mbus; 27 struct snap *sp; 28 29 if ((sp = kmalloc(sizeof(struct snap), GFP_KERNEL)) == NULL) 30 return -ENOMEM; 31 32 mbus = inode->i_private; 33 34 sp->slen = snprintf(sp->str, STAT_BUF_SIZE, 35 "nreaders %d events %u text_lost %u\n", 36 mbus->nreaders, mbus->cnt_events, mbus->cnt_text_lost); 37 38 file->private_data = sp; 39 return 0; 40 } 41 42 static ssize_t mon_stat_read(struct file *file, char __user *buf, 43 size_t nbytes, loff_t *ppos) 44 { 45 struct snap *sp = file->private_data; 46 47 return simple_read_from_buffer(buf, nbytes, ppos, sp->str, sp->slen); 48 } 49 50 static int mon_stat_release(struct inode *inode, struct file *file) 51 { 52 struct snap *sp = file->private_data; 53 file->private_data = NULL; 54 kfree(sp); 55 return 0; 56 } 57 58 const struct file_operations mon_fops_stat = { 59 .owner = THIS_MODULE, 60 .open = mon_stat_open, 61 .llseek = no_llseek, 62 .read = mon_stat_read, 63 /* .write = mon_stat_write, */ 64 /* .poll = mon_stat_poll, */ 65 /* .ioctl = mon_stat_ioctl, */ 66 .release = mon_stat_release, 67 }; 68