uprobes.h

#ifndef _LTTNG_WRAPPER_UPROBES_H
#define _LTTNG_WRAPPER_UPROBES_H

/*
 * wrapper/uprobes.h
 *
 * wrapper around uprobes. Using KALLSYMS to get its address when
 * available, else we need to have a kernel that exports this function to GPL
 * modules.
 *
 * Copyright (C) 2013 Yannick Brosseau <yannick.brosseau@gmail.com>
 * Copyright (C) 2017 Francis Deslauriers <francis.deslauriers@efficios.com>
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; only
 * version 2.1 of the License.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

#include <linux/version.h>

#if (LINUX_VERSION_CODE >= KERNEL_VERSION(3,5,0))
#include <linux/uprobes.h>

/* Use kallsym lookup for version before 3.9. */
#if (LINUX_VERSION_CODE >= KERNEL_VERSION(3,9,0))

static inline
int wrapper_uprobe_register(struct inode *inode, loff_t offset, struct uprobe_consumer *uc)
{
	return uprobe_register(inode, offset, uc);
}

static inline
void wrapper_uprobe_unregister(struct inode *inode, loff_t offset, struct uprobe_consumer *uc)
{
	uprobe_unregister(inode, offset, uc);
}

#else /* Version < 3.9, use kallsym lookup. */
#include "kallsyms.h"

static inline
int wrapper_uprobe_register(struct inode *inode, loff_t offset, struct uprobe_consumer *uc)
{
	int (*uprobe_register_sym)(struct inode *inode, loff_t offset, struct uprobe_consumer *uc);

	uprobe_register_sym = (void *) kallsyms_lookup_funcptr("uprobe_register");

	if (uprobe_register_sym) {
		return uprobe_register_sym(inode, offset, uc);
	} else {
                printk(KERN_WARNING "LTTng: uprobe_register symbol lookup failed.\n");
                return -EINVAL;
	}
}

static inline
void wrapper_uprobe_unregister(struct inode *inode, loff_t offset, struct uprobe_consumer *uc)
{
        int (*uprobe_unregister_sym)(struct inode *inode, loff_t offset, struct uprobe_consumer *uc);

        uprobe_unregister_sym = (void *) kallsyms_lookup_funcptr("uprobe_unregister");

        if (uprobe_unregister_sym) {
                uprobe_unregister_sym(inode, offset, uc);
        } else {
                printk(KERN_WARNING "LTTng: uprobe_unregister symbol lookup failed.\n");
                WARN_ON(1);
        }
}
#endif
#else
/* Version <  3.5, before uprobe was added. */
struct uprobe_consumer {};

#endif
#endif