/usr/src/lttng-modules-2.5.1/probes/lttng-kprobes.c is in lttng-modules-dkms 2.5.1-1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 | /*
* probes/lttng-kprobes.c
*
* LTTng kprobes integration module.
*
* Copyright (C) 2009-2012 Mathieu Desnoyers <mathieu.desnoyers@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/module.h>
#include <linux/kprobes.h>
#include <linux/slab.h>
#include "../lttng-events.h"
#include "../wrapper/ringbuffer/frontend_types.h"
#include "../wrapper/vmalloc.h"
#include "../lttng-tracer.h"
static
int lttng_kprobes_handler_pre(struct kprobe *p, struct pt_regs *regs)
{
struct lttng_event *event =
container_of(p, struct lttng_event, u.kprobe.kp);
struct lttng_channel *chan = event->chan;
struct lib_ring_buffer_ctx ctx;
int ret;
unsigned long data = (unsigned long) p->addr;
if (unlikely(!ACCESS_ONCE(chan->session->active)))
return 0;
if (unlikely(!ACCESS_ONCE(chan->enabled)))
return 0;
if (unlikely(!ACCESS_ONCE(event->enabled)))
return 0;
lib_ring_buffer_ctx_init(&ctx, chan->chan, event, sizeof(data),
lttng_alignof(data), -1);
ret = chan->ops->event_reserve(&ctx, event->id);
if (ret < 0)
return 0;
lib_ring_buffer_align_ctx(&ctx, lttng_alignof(data));
chan->ops->event_write(&ctx, &data, sizeof(data));
chan->ops->event_commit(&ctx);
return 0;
}
/*
* Create event description
*/
static
int lttng_create_kprobe_event(const char *name, struct lttng_event *event)
{
struct lttng_event_field *field;
struct lttng_event_desc *desc;
int ret;
desc = kzalloc(sizeof(*event->desc), GFP_KERNEL);
if (!desc)
return -ENOMEM;
desc->name = kstrdup(name, GFP_KERNEL);
if (!desc->name) {
ret = -ENOMEM;
goto error_str;
}
desc->nr_fields = 1;
desc->fields = field =
kzalloc(1 * sizeof(struct lttng_event_field), GFP_KERNEL);
if (!field) {
ret = -ENOMEM;
goto error_field;
}
field->name = "ip";
field->type.atype = atype_integer;
field->type.u.basic.integer.size = sizeof(unsigned long) * CHAR_BIT;
field->type.u.basic.integer.alignment = lttng_alignof(unsigned long) * CHAR_BIT;
field->type.u.basic.integer.signedness = lttng_is_signed_type(unsigned long);
field->type.u.basic.integer.reverse_byte_order = 0;
field->type.u.basic.integer.base = 16;
field->type.u.basic.integer.encoding = lttng_encode_none;
desc->owner = THIS_MODULE;
event->desc = desc;
return 0;
error_field:
kfree(desc->name);
error_str:
kfree(desc);
return ret;
}
int lttng_kprobes_register(const char *name,
const char *symbol_name,
uint64_t offset,
uint64_t addr,
struct lttng_event *event)
{
int ret;
/* Kprobes expects a NULL symbol name if unused */
if (symbol_name[0] == '\0')
symbol_name = NULL;
ret = lttng_create_kprobe_event(name, event);
if (ret)
goto error;
memset(&event->u.kprobe.kp, 0, sizeof(event->u.kprobe.kp));
event->u.kprobe.kp.pre_handler = lttng_kprobes_handler_pre;
if (symbol_name) {
event->u.kprobe.symbol_name =
kzalloc(LTTNG_KERNEL_SYM_NAME_LEN * sizeof(char),
GFP_KERNEL);
if (!event->u.kprobe.symbol_name) {
ret = -ENOMEM;
goto name_error;
}
memcpy(event->u.kprobe.symbol_name, symbol_name,
LTTNG_KERNEL_SYM_NAME_LEN * sizeof(char));
event->u.kprobe.kp.symbol_name =
event->u.kprobe.symbol_name;
}
event->u.kprobe.kp.offset = offset;
event->u.kprobe.kp.addr = (void *) (unsigned long) addr;
/*
* Ensure the memory we just allocated don't trigger page faults.
* Well.. kprobes itself puts the page fault handler on the blacklist,
* but we can never be too careful.
*/
wrapper_vmalloc_sync_all();
ret = register_kprobe(&event->u.kprobe.kp);
if (ret)
goto register_error;
return 0;
register_error:
kfree(event->u.kprobe.symbol_name);
name_error:
kfree(event->desc->fields);
kfree(event->desc->name);
kfree(event->desc);
error:
return ret;
}
EXPORT_SYMBOL_GPL(lttng_kprobes_register);
void lttng_kprobes_unregister(struct lttng_event *event)
{
unregister_kprobe(&event->u.kprobe.kp);
}
EXPORT_SYMBOL_GPL(lttng_kprobes_unregister);
void lttng_kprobes_destroy_private(struct lttng_event *event)
{
kfree(event->u.kprobe.symbol_name);
kfree(event->desc->fields);
kfree(event->desc->name);
kfree(event->desc);
}
EXPORT_SYMBOL_GPL(lttng_kprobes_destroy_private);
MODULE_LICENSE("GPL and additional rights");
MODULE_AUTHOR("Mathieu Desnoyers");
MODULE_DESCRIPTION("Linux Trace Toolkit Kprobes Support");
MODULE_VERSION(__stringify(LTTNG_MODULES_MAJOR_VERSION) "."
__stringify(LTTNG_MODULES_MINOR_VERSION) "."
__stringify(LTTNG_MODULES_PATCHLEVEL_VERSION)
LTTNG_MODULES_EXTRAVERSION);
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