wrapper/uprobes.h

   1 /* SPDX-License-Identifier: (GPL-2.0 or LGPL-2.1)
   2  *
   3  * wrapper/uprobes.h
   4  *
   5  * wrapper around uprobes. Using KALLSYMS to get its address when
   6  * available, else we need to have a kernel that exports this function to GPL
   7  * modules.
   8  *
   9  * Copyright (C) 2013 Yannick Brosseau <yannick.brosseau@gmail.com>
  10  * Copyright (C) 2017 Francis Deslauriers <francis.deslauriers@efficios.com>
  11  *
  12  */
  13
  14 #ifndef _LTTNG_WRAPPER_UPROBES_H
  15 #define _LTTNG_WRAPPER_UPROBES_H
  16
  17 #include <linux/version.h>
  18
  19 #if (LINUX_VERSION_CODE >= KERNEL_VERSION(3,5,0))
  20 #include <linux/uprobes.h>
  21
  22 /* Use kallsym lookup for version before 3.9. */
  23 #if (LINUX_VERSION_CODE >= KERNEL_VERSION(3,9,0))
  24
  25 static inline
  26 int wrapper_uprobe_register(struct inode *inode, loff_t offset, struct uprobe_consumer *uc)
  27 {
  28         return uprobe_register(inode, offset, uc);
  29 }
  30
  31 static inline
  32 void wrapper_uprobe_unregister(struct inode *inode, loff_t offset, struct uprobe_consumer *uc)
  33 {
  34         uprobe_unregister(inode, offset, uc);
  35 }
  36
  37 #else /* Version < 3.9, use kallsym lookup. */
  38 #include "kallsyms.h"
  39
  40 static inline
  41 int wrapper_uprobe_register(struct inode *inode, loff_t offset, struct uprobe_consumer *uc)
  42 {
  43         int (*uprobe_register_sym)(struct inode *inode, loff_t offset, struct uprobe_consumer *uc);
  44
  45         uprobe_register_sym = (void *) kallsyms_lookup_funcptr("uprobe_register");
  46
  47         if (uprobe_register_sym) {
  48                 return uprobe_register_sym(inode, offset, uc);
  49         } else {
  50                 printk(KERN_WARNING "LTTng: uprobe_register symbol lookup failed.\n");
  51                 return -EINVAL;
  52         }
  53 }
  54
  55 static inline
  56 void wrapper_uprobe_unregister(struct inode *inode, loff_t offset, struct uprobe_consumer *uc)
  57 {
  58         int (*uprobe_unregister_sym)(struct inode *inode, loff_t offset, struct uprobe_consumer *uc);
  59
  60         uprobe_unregister_sym = (void *) kallsyms_lookup_funcptr("uprobe_unregister");
  61
  62         if (uprobe_unregister_sym) {
  63                 uprobe_unregister_sym(inode, offset, uc);
  64         } else {
  65                 printk(KERN_WARNING "LTTng: uprobe_unregister symbol lookup failed.\n");
  66                 WARN_ON(1);
  67         }
  68 }
  69 #endif
  70 #else
  71 /* Version <  3.5, before uprobe was added. */
  72 struct uprobe_consumer {};
  73
  74 #endif
  75 #endif