fix get_ioctl_names.sh

[moctel.git] / moctel_mod.c

diff --git a/moctel_mod.c b/moctel_mod.c
index 47d63f8..1273ff3 100644 (file)
--- a/moctel_mod.c
+++ b/moctel_mod.c
@@ -1,3 +1,7 @@
+// Copyright (C) 2013 Jann Horn <jann@thejh.net>
+// This file is licensed under the GNU GPL v2 (see
+// the LICENSE file).
+
 #undef __KERNEL__
 #define __KERNEL__
 #undef MODULE
@@ -11,6 +15,8 @@
 #include <linux/ioctl.h>
 #include <linux/uaccess.h>
 #include <linux/miscdevice.h>
+#include <linux/kallsyms.h>
+#include <linux/blkdev.h>
 
 struct fetch_fops_args {
   int fd;
@@ -23,21 +29,29 @@ static int ioctl_open(struct inode *nodp, struct file *filp) {
   return 0;
 }
 
-static const struct file_operations dummy_fops = {};
-
 static long ioctl_ioctl(struct file *filp_, unsigned int cmd, unsigned long arg) {
   struct fetch_fops_args args;
   struct file *filp;
-  const struct file_operations *fops;
+  void *ioctl_method = NULL;
+  char ioctl_method_name[KSYM_NAME_LEN];
+  int (*lookup_symbol_name_)(unsigned long addr, char *symname);
+
+  lookup_symbol_name_ = (void*)kallsyms_lookup_name("lookup_symbol_name");
 
   if (cmd != MOCTEL_FETCH_FOPS) return -EINVAL;
+  memset(ioctl_method_name, 0, sizeof(ioctl_method_name));
   if (copy_from_user(&args, (struct fetch_fops_args __user *)arg, sizeof(args))) return -EINVAL;
   filp = fget(args.fd);
   if (!filp) return -EBADF;
-  fops = filp->f_op;
-  if (!fops) fops = &dummy_fops;
+  if (filp->f_op) ioctl_method = filp->f_op->unlocked_ioctl;
+  lookup_symbol_name_((unsigned long)ioctl_method, ioctl_method_name);
+  if (strcmp(ioctl_method_name, "block_ioctl") == 0) {
+    struct block_device *bdev = I_BDEV(filp->f_mapping->host);
+    ioctl_method = bdev->bd_disk->fops->ioctl;
+    lookup_symbol_name_((unsigned long)ioctl_method, ioctl_method_name);
+  }
   fput(filp);
-  if (copy_to_user((struct file_operations __user *)args.retp, fops, sizeof(*fops))) return -EINVAL;
+  if (copy_to_user((struct file_operations __user *)args.retp, ioctl_method_name, KSYM_NAME_LEN)) return -EINVAL;
   return 0;
 }
 
@@ -73,3 +87,5 @@ static void __exit cleanup_ioctl(void) {
 
 module_init(init_ioctl);
 module_exit(cleanup_ioctl);
+
+MODULE_LICENSE("GPL v2");