include/wrapper/uprobes.h

   1 /* SPDX-License-Identifier: (GPL-2.0-only or LGPL-2.1-only)
   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 <lttng/kernel-version.h>
  18
  19 #if (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(3,5,0))
  20 #include <linux/uprobes.h>
  21
  22 /* Use kallsym lookup for version before 3.9. */
  23 #if (LTTNG_LINUX_VERSION_CODE >= LTTNG_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 /*
  56  * Canary function to check for 'uprobe_register()' at compile time.
  57  *
  58  * From 'include/linux/uprobes.h':
  59  *
  60  *   extern int uprobe_register(struct inode *inode, loff_t offset, struct uprobe_consumer *uc);
  61  */
  62 static inline
  63 int __canary__uprobe_register(struct inode *inode, loff_t offset, struct uprobe_consumer *uc)
  64 {
  65         return uprobe_register(inode, offset, uc);
  66 }
  67
  68 static inline
  69 void wrapper_uprobe_unregister(struct inode *inode, loff_t offset, struct uprobe_consumer *uc)
  70 {
  71         int (*uprobe_unregister_sym)(struct inode *inode, loff_t offset, struct uprobe_consumer *uc);
  72
  73         uprobe_unregister_sym = (void *) kallsyms_lookup_funcptr("uprobe_unregister");
  74
  75         if (uprobe_unregister_sym) {
  76                 uprobe_unregister_sym(inode, offset, uc);
  77         } else {
  78                 printk(KERN_WARNING "LTTng: uprobe_unregister symbol lookup failed.\n");
  79                 WARN_ON(1);
  80         }
  81 }
  82
  83 /*
  84  * Canary function to check for 'uprobe_unregister()' at compile time.
  85  *
  86  * From 'include/linux/uprobes.h':
  87  *
  88  *   extern void uprobe_unregister(struct inode *inode, loff_t offset, struct uprobe_consumer *uc);
  89  */
  90 static inline
  91 void __canary__uprobe_unregister(struct inode *inode, loff_t offset, struct uprobe_consumer *uc)
  92 {
  93         uprobe_unregister(inode, offset, uc);
  94 }
  95
  96 #endif
  97 #else
  98 /* Version <  3.5, before uprobe was added. */
  99 struct uprobe_consumer {};
 100
 101 #endif
 102 #endif