1 /* SPDX-License-Identifier: (GPL-2.0-only OR LGPL-2.1-only)
3 * probes/lttng-uprobes.c
5 * LTTng uprobes integration module.
7 * Copyright (C) 2013 Yannick Brosseau <yannick.brosseau@gmail.com>
8 * Copyright (C) 2009-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
12 #include <wrapper/fdtable.h>
13 #include <linux/list.h>
14 #include <linux/module.h>
15 #include <linux/namei.h>
16 #include <linux/slab.h>
17 #include <linux/uaccess.h>
18 #include <lttng/events.h>
19 #include <lttng/tracer.h>
20 #include <wrapper/irqflags.h>
21 #include <ringbuffer/frontend_types.h>
22 #include <wrapper/uprobes.h>
23 #include <wrapper/vmalloc.h>
26 int lttng_uprobes_event_handler_pre(struct uprobe_consumer
*uc
, struct pt_regs
*regs
)
28 struct lttng_uprobe_handler
*uprobe_handler
=
29 container_of(uc
, struct lttng_uprobe_handler
, up_consumer
);
30 struct lttng_event
*event
= uprobe_handler
->u
.event
;
31 struct lttng_probe_ctx lttng_probe_ctx
= {
33 .interruptible
= !lttng_regs_irqs_disabled(regs
),
35 struct lttng_channel
*chan
= event
->chan
;
36 struct lib_ring_buffer_ctx ctx
;
43 if (unlikely(!LTTNG_READ_ONCE(chan
->session
->active
)))
45 if (unlikely(!LTTNG_READ_ONCE(chan
->enabled
)))
47 if (unlikely(!LTTNG_READ_ONCE(event
->enabled
)))
50 lib_ring_buffer_ctx_init(&ctx
, chan
->chan
, <tng_probe_ctx
,
51 sizeof(payload
), lttng_alignof(payload
), -1);
53 ret
= chan
->ops
->event_reserve(&ctx
, event
->id
);
58 payload
.ip
= (unsigned long)instruction_pointer(regs
);
60 lib_ring_buffer_align_ctx(&ctx
, lttng_alignof(payload
));
61 chan
->ops
->event_write(&ctx
, &payload
, sizeof(payload
));
62 chan
->ops
->event_commit(&ctx
);
67 int lttng_uprobes_event_notifier_handler_pre(struct uprobe_consumer
*uc
, struct pt_regs
*regs
)
69 struct lttng_uprobe_handler
*uprobe_handler
=
70 container_of(uc
, struct lttng_uprobe_handler
, up_consumer
);
71 struct lttng_event_notifier
*event_notifier
= uprobe_handler
->u
.event_notifier
;
72 struct lttng_kernel_notifier_ctx notif_ctx
;
74 if (unlikely(!READ_ONCE(event_notifier
->enabled
)))
77 notif_ctx
.eval_capture
= LTTNG_READ_ONCE(event_notifier
->eval_capture
);
78 event_notifier
->send_notification(event_notifier
, NULL
, NULL
, ¬if_ctx
);
82 static const struct lttng_kernel_type_common
*event_type
=
83 lttng_kernel_static_type_integer_from_type(unsigned long, __BYTE_ORDER
, 16);
86 * Create event description.
89 int lttng_create_uprobe_event(const char *name
, struct lttng_event
*event
)
91 const struct lttng_kernel_event_field
**fieldp_array
;
92 struct lttng_kernel_event_field
*field
;
93 struct lttng_kernel_event_desc
*desc
;
96 desc
= kzalloc(sizeof(*desc
), GFP_KERNEL
);
99 desc
->event_name
= kstrdup(name
, GFP_KERNEL
);
100 if (!desc
->event_name
) {
105 fieldp_array
= kzalloc(1 * sizeof(struct lttng_kernel_event_field
*), GFP_KERNEL
);
108 goto error_fieldp_array
;
110 desc
->fields
= fieldp_array
;
111 desc
->fields
[0] = field
=
112 kzalloc(sizeof(struct lttng_kernel_event_field
), GFP_KERNEL
);
118 field
->type
= event_type
;
119 desc
->owner
= THIS_MODULE
;
127 kfree(desc
->event_name
);
134 * Create event_notifier description.
137 int lttng_create_uprobe_event_notifier(const char *name
, struct lttng_event_notifier
*event_notifier
)
139 struct lttng_kernel_event_desc
*desc
;
142 desc
= kzalloc(sizeof(*desc
), GFP_KERNEL
);
145 desc
->event_name
= kstrdup(name
, GFP_KERNEL
);
146 if (!desc
->event_name
) {
153 desc
->owner
= THIS_MODULE
;
154 event_notifier
->desc
= desc
;
164 * Returns the inode struct from the current task and an fd. The inode is
165 * grabbed by this function and must be put once we are done with it using
168 static struct inode
*get_inode_from_fd(int fd
)
175 * Returns the file backing the given fd. Needs to be done inside an RCU
178 file
= lttng_lookup_fd_rcu(fd
);
180 printk(KERN_WARNING
"LTTng: Cannot access file backing the fd(%d)\n", fd
);
185 /* Grab a reference on the inode. */
186 inode
= igrab(file
->f_path
.dentry
->d_inode
);
188 printk(KERN_WARNING
"LTTng: Cannot grab a reference on the inode.\n");
196 int lttng_uprobes_add_callsite(struct lttng_uprobe
*uprobe
,
197 struct lttng_kernel_event_callsite __user
*callsite
,
198 int (*handler
)(struct uprobe_consumer
*self
, struct pt_regs
*regs
),
202 struct lttng_uprobe_handler
*uprobe_handler
;
209 uprobe_handler
= kzalloc(sizeof(struct lttng_uprobe_handler
), GFP_KERNEL
);
210 if (!uprobe_handler
) {
211 printk(KERN_WARNING
"LTTng: Error allocating uprobe_handler");
216 /* Ensure the memory we just allocated don't notify page faults. */
217 wrapper_vmalloc_sync_mappings();
219 uprobe_handler
->u
.event
= priv_data
;
220 uprobe_handler
->up_consumer
.handler
= handler
;
222 ret
= copy_from_user(&uprobe_handler
->offset
, &callsite
->u
.uprobe
.offset
, sizeof(uint64_t));
227 ret
= wrapper_uprobe_register(uprobe
->inode
,
228 uprobe_handler
->offset
, &uprobe_handler
->up_consumer
);
230 printk(KERN_WARNING
"LTTng: Error registering probe on inode %lu "
231 "and offset 0x%llx\n", uprobe
->inode
->i_ino
,
232 uprobe_handler
->offset
);
237 list_add(&uprobe_handler
->node
, &uprobe
->head
);
242 kfree(uprobe_handler
);
247 int lttng_uprobes_event_add_callsite(struct lttng_event
*event
,
248 struct lttng_kernel_event_callsite __user
*callsite
)
250 return lttng_uprobes_add_callsite(&event
->u
.uprobe
, callsite
,
251 lttng_uprobes_event_handler_pre
, event
);
253 EXPORT_SYMBOL_GPL(lttng_uprobes_event_add_callsite
);
255 int lttng_uprobes_event_notifier_add_callsite(struct lttng_event_notifier
*event_notifier
,
256 struct lttng_kernel_event_callsite __user
*callsite
)
258 return lttng_uprobes_add_callsite(&event_notifier
->u
.uprobe
, callsite
,
259 lttng_uprobes_event_notifier_handler_pre
, event_notifier
);
261 EXPORT_SYMBOL_GPL(lttng_uprobes_event_notifier_add_callsite
);
264 int lttng_uprobes_register(struct lttng_uprobe
*uprobe
, int fd
)
269 inode
= get_inode_from_fd(fd
);
271 printk(KERN_WARNING
"LTTng: Cannot get inode from fd\n");
275 uprobe
->inode
= inode
;
276 INIT_LIST_HEAD(&uprobe
->head
);
282 int lttng_uprobes_register_event(const char *name
, int fd
, struct lttng_event
*event
)
286 ret
= lttng_create_uprobe_event(name
, event
);
290 ret
= lttng_uprobes_register(&event
->u
.uprobe
, fd
);
297 kfree(event
->desc
->event_name
);
302 EXPORT_SYMBOL_GPL(lttng_uprobes_register_event
);
304 int lttng_uprobes_register_event_notifier(const char *name
, int fd
,
305 struct lttng_event_notifier
*event_notifier
)
309 ret
= lttng_create_uprobe_event_notifier(name
, event_notifier
);
313 ret
= lttng_uprobes_register(&event_notifier
->u
.uprobe
, fd
);
320 kfree(event_notifier
->desc
->event_name
);
321 kfree(event_notifier
->desc
);
325 EXPORT_SYMBOL_GPL(lttng_uprobes_register_event_notifier
);
328 void lttng_uprobes_unregister(struct inode
*inode
, struct list_head
*head
)
330 struct lttng_uprobe_handler
*iter
, *tmp
;
333 * Iterate over the list of handler, remove each handler from the list
334 * and free the struct.
336 list_for_each_entry_safe(iter
, tmp
, head
, node
) {
337 wrapper_uprobe_unregister(inode
, iter
->offset
, &iter
->up_consumer
);
338 list_del(&iter
->node
);
344 void lttng_uprobes_unregister_event(struct lttng_event
*event
)
346 lttng_uprobes_unregister(event
->u
.uprobe
.inode
, &event
->u
.uprobe
.head
);
348 EXPORT_SYMBOL_GPL(lttng_uprobes_unregister_event
);
350 void lttng_uprobes_unregister_event_notifier(struct lttng_event_notifier
*event_notifier
)
352 lttng_uprobes_unregister(event_notifier
->u
.uprobe
.inode
, &event_notifier
->u
.uprobe
.head
);
354 EXPORT_SYMBOL_GPL(lttng_uprobes_unregister_event_notifier
);
356 void lttng_uprobes_destroy_event_private(struct lttng_event
*event
)
358 iput(event
->u
.uprobe
.inode
);
359 kfree(event
->desc
->fields
[0]);
360 kfree(event
->desc
->fields
);
361 kfree(event
->desc
->event_name
);
364 EXPORT_SYMBOL_GPL(lttng_uprobes_destroy_event_private
);
366 void lttng_uprobes_destroy_event_notifier_private(struct lttng_event_notifier
*event_notifier
)
368 iput(event_notifier
->u
.uprobe
.inode
);
369 kfree(event_notifier
->desc
->event_name
);
370 kfree(event_notifier
->desc
);
372 EXPORT_SYMBOL_GPL(lttng_uprobes_destroy_event_notifier_private
);
374 MODULE_LICENSE("GPL and additional rights");
375 MODULE_AUTHOR("Yannick Brosseau");
376 MODULE_DESCRIPTION("Linux Trace Toolkit Uprobes Support");