wrapper/uprobes.h

   1 #ifndef _LTTNG_WRAPPER_UPROBES_H
   2 #define _LTTNG_WRAPPER_UPROBES_H
   3
   4 /*
   5  * wrapper/uprobes.h
   6  *
   7  * wrapper around uprobes. Using KALLSYMS to get its address when
   8  * available, else we need to have a kernel that exports this function to GPL
   9  * modules.
  10  *
  11  * Copyright (C) 2013 Yannick Brosseau <yannick.brosseau@gmail.com>
  12  * Copyright (C) 2017 Francis Deslauriers <francis.deslauriers@efficios.com>
  13  *
  14  * This library is free software; you can redistribute it and/or
  15  * modify it under the terms of the GNU Lesser General Public
  16  * License as published by the Free Software Foundation; only
  17  * version 2.1 of the License.
  18  *
  19  * This library is distributed in the hope that it will be useful,
  20  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  21  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  22  * Lesser General Public License for more details.
  23  *
  24  * You should have received a copy of the GNU Lesser General Public
  25  * License along with this library; if not, write to the Free Software
  26  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  27  */
  28
  29 #include <linux/version.h>
  30
  31 #if (LINUX_VERSION_CODE >= KERNEL_VERSION(3,5,0))
  32 #include <linux/uprobes.h>
  33
  34 /* Use kallsym lookup for version before 3.9. */
  35 #if (LINUX_VERSION_CODE >= KERNEL_VERSION(3,9,0))
  36
  37 static inline
  38 int wrapper_uprobe_register(struct inode *inode, loff_t offset, struct uprobe_consumer *uc)
  39 {
  40         return uprobe_register(inode, offset, uc);
  41 }
  42
  43 static inline
  44 void wrapper_uprobe_unregister(struct inode *inode, loff_t offset, struct uprobe_consumer *uc)
  45 {
  46         uprobe_unregister(inode, offset, uc);
  47 }
  48
  49 #else /* Version < 3.9, use kallsym lookup. */
  50 #include "kallsyms.h"
  51
  52 static inline
  53 int wrapper_uprobe_register(struct inode *inode, loff_t offset, struct uprobe_consumer *uc)
  54 {
  55         int (*uprobe_register_sym)(struct inode *inode, loff_t offset, struct uprobe_consumer *uc);
  56
  57         uprobe_register_sym = (void *) kallsyms_lookup_funcptr("uprobe_register");
  58
  59         if (uprobe_register_sym) {
  60                 return uprobe_register_sym(inode, offset, uc);
  61         } else {
  62                 printk(KERN_WARNING "LTTng: uprobe_register symbol lookup failed.\n");
  63                 return -EINVAL;
  64         }
  65 }
  66
  67 static inline
  68 void wrapper_uprobe_unregister(struct inode *inode, loff_t offset, struct uprobe_consumer *uc)
  69 {
  70         int (*uprobe_unregister_sym)(struct inode *inode, loff_t offset, struct uprobe_consumer *uc);
  71
  72         uprobe_unregister_sym = (void *) kallsyms_lookup_funcptr("uprobe_unregister");
  73
  74         if (uprobe_unregister_sym) {
  75                 uprobe_unregister_sym(inode, offset, uc);
  76         } else {
  77                 printk(KERN_WARNING "LTTng: uprobe_unregister symbol lookup failed.\n");
  78                 WARN_ON(1);
  79         }
  80 }
  81 #endif
  82 #else
  83 /* Version <  3.5, before uprobe was added. */
  84 struct uprobe_consumer {};
  85
  86 #endif
  87 #endif