1 files changed, 74 insertions, 0 deletions

diff --git a/drivers/usb/mon/mon_stat.c b/drivers/usb/mon/mon_stat.c
new file mode 100644
index 000000000000..6e4b165d070a
--- /dev/null
+++ b/drivers/usb/mon/mon_stat.c
@@ -0,0 +1,74 @@
+/*
+ * 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/usb.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->u.generic_ip;
+
+        sp->slen = snprintf(sp->str, STAT_BUF_SIZE,
+            "nreaders %d text_lost %u\n",
+            mbus->nreaders, 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;
+        loff_t pos = *ppos;
+        int cnt;
+
+        if (pos < 0 || pos >= sp->slen)
+                return 0;
+        if (nbytes == 0)
+                return 0;
+        if ((cnt = sp->slen - pos) > nbytes)
+                cnt = nbytes;
+        if (copy_to_user(buf, sp->str + pos, cnt))
+                return -EFAULT;
+        *ppos = pos + cnt;
+        return cnt;
+}
+
+static int mon_stat_release(struct inode *inode, struct file *file)
+{
+        return 0;
+}
+
+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,
+};