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/events-internal.h>
20 #include <lttng/tracer.h>
21 #include <wrapper/irqflags.h>
22 #include <ringbuffer/frontend_types.h>
23 #include <wrapper/uprobes.h>
24 #include <wrapper/vmalloc.h>
27 int lttng_uprobes_event_handler_pre(struct uprobe_consumer
*uc
, struct pt_regs
*regs
)
29 struct lttng_uprobe_handler
*uprobe_handler
=
30 container_of(uc
, struct lttng_uprobe_handler
, up_consumer
);
31 struct lttng_kernel_event_recorder
*event_recorder
= uprobe_handler
->u
.event
;
32 struct lttng_probe_ctx lttng_probe_ctx
= {
33 .event
= event_recorder
,
34 .interruptible
= !lttng_regs_irqs_disabled(regs
),
36 struct lttng_channel
*chan
= event_recorder
->chan
;
37 struct lib_ring_buffer_ctx ctx
;
44 if (unlikely(!LTTNG_READ_ONCE(chan
->session
->active
)))
46 if (unlikely(!LTTNG_READ_ONCE(chan
->enabled
)))
48 if (unlikely(!LTTNG_READ_ONCE(event_recorder
->parent
.enabled
)))
51 lib_ring_buffer_ctx_init(&ctx
, chan
->chan
, <tng_probe_ctx
,
52 sizeof(payload
), lttng_alignof(payload
), -1);
54 ret
= chan
->ops
->event_reserve(&ctx
, event_recorder
->priv
->id
);
59 payload
.ip
= (unsigned long)instruction_pointer(regs
);
61 lib_ring_buffer_align_ctx(&ctx
, lttng_alignof(payload
));
62 chan
->ops
->event_write(&ctx
, &payload
, sizeof(payload
));
63 chan
->ops
->event_commit(&ctx
);
68 int lttng_uprobes_event_notifier_handler_pre(struct uprobe_consumer
*uc
, struct pt_regs
*regs
)
70 struct lttng_uprobe_handler
*uprobe_handler
=
71 container_of(uc
, struct lttng_uprobe_handler
, up_consumer
);
72 struct lttng_kernel_event_notifier
*event_notifier
= uprobe_handler
->u
.event_notifier
;
73 struct lttng_kernel_notification_ctx notif_ctx
;
75 if (unlikely(!READ_ONCE(event_notifier
->parent
.enabled
)))
78 notif_ctx
.eval_capture
= LTTNG_READ_ONCE(event_notifier
->eval_capture
);
79 event_notifier
->notification_send(event_notifier
, NULL
, NULL
, ¬if_ctx
);
83 static const struct lttng_kernel_type_common
*event_type
=
84 lttng_kernel_static_type_integer_from_type(unsigned long, __BYTE_ORDER
, 16);
87 * Create event description.
90 int lttng_create_uprobe_event(const char *name
, struct lttng_kernel_event_recorder
*event_recorder
)
92 const struct lttng_kernel_event_field
**fieldp_array
;
93 struct lttng_kernel_event_field
*field
;
94 struct lttng_kernel_event_desc
*desc
;
97 desc
= kzalloc(sizeof(*desc
), GFP_KERNEL
);
100 desc
->event_name
= kstrdup(name
, GFP_KERNEL
);
101 if (!desc
->event_name
) {
106 fieldp_array
= kzalloc(1 * sizeof(struct lttng_kernel_event_field
*), GFP_KERNEL
);
109 goto error_fieldp_array
;
111 desc
->fields
= fieldp_array
;
112 desc
->fields
[0] = field
=
113 kzalloc(sizeof(struct lttng_kernel_event_field
), GFP_KERNEL
);
119 field
->type
= event_type
;
120 desc
->owner
= THIS_MODULE
;
121 event_recorder
->priv
->parent
.desc
= desc
;
128 kfree(desc
->event_name
);
135 * Create event_notifier description.
138 int lttng_create_uprobe_event_notifier(const char *name
, struct lttng_kernel_event_notifier
*event_notifier
)
140 struct lttng_kernel_event_desc
*desc
;
143 desc
= kzalloc(sizeof(*desc
), GFP_KERNEL
);
146 desc
->event_name
= kstrdup(name
, GFP_KERNEL
);
147 if (!desc
->event_name
) {
154 desc
->owner
= THIS_MODULE
;
155 event_notifier
->priv
->parent
.desc
= desc
;
165 * Returns the inode struct from the current task and an fd. The inode is
166 * grabbed by this function and must be put once we are done with it using
169 static struct inode
*get_inode_from_fd(int fd
)
176 * Returns the file backing the given fd. Needs to be done inside an RCU
179 file
= lttng_lookup_fd_rcu(fd
);
181 printk(KERN_WARNING
"LTTng: Cannot access file backing the fd(%d)\n", fd
);
186 /* Grab a reference on the inode. */
187 inode
= igrab(file
->f_path
.dentry
->d_inode
);
189 printk(KERN_WARNING
"LTTng: Cannot grab a reference on the inode.\n");
197 int lttng_uprobes_add_callsite(struct lttng_uprobe
*uprobe
,
198 struct lttng_kernel_abi_event_callsite __user
*callsite
,
199 int (*handler
)(struct uprobe_consumer
*self
, struct pt_regs
*regs
),
203 struct lttng_uprobe_handler
*uprobe_handler
;
210 uprobe_handler
= kzalloc(sizeof(struct lttng_uprobe_handler
), GFP_KERNEL
);
211 if (!uprobe_handler
) {
212 printk(KERN_WARNING
"LTTng: Error allocating uprobe_handler");
217 /* Ensure the memory we just allocated don't notify page faults. */
218 wrapper_vmalloc_sync_mappings();
220 uprobe_handler
->u
.event
= priv_data
;
221 uprobe_handler
->up_consumer
.handler
= handler
;
223 ret
= copy_from_user(&uprobe_handler
->offset
, &callsite
->u
.uprobe
.offset
, sizeof(uint64_t));
228 ret
= wrapper_uprobe_register(uprobe
->inode
,
229 uprobe_handler
->offset
, &uprobe_handler
->up_consumer
);
231 printk(KERN_WARNING
"LTTng: Error registering probe on inode %lu "
232 "and offset 0x%llx\n", uprobe
->inode
->i_ino
,
233 uprobe_handler
->offset
);
238 list_add(&uprobe_handler
->node
, &uprobe
->head
);
243 kfree(uprobe_handler
);
248 int lttng_uprobes_event_add_callsite(struct lttng_kernel_event_recorder
*event_recorder
,
249 struct lttng_kernel_abi_event_callsite __user
*callsite
)
251 return lttng_uprobes_add_callsite(&event_recorder
->priv
->parent
.u
.uprobe
, callsite
,
252 lttng_uprobes_event_handler_pre
, event_recorder
);
254 EXPORT_SYMBOL_GPL(lttng_uprobes_event_add_callsite
);
256 int lttng_uprobes_event_notifier_add_callsite(struct lttng_kernel_event_notifier
*event_notifier
,
257 struct lttng_kernel_abi_event_callsite __user
*callsite
)
259 return lttng_uprobes_add_callsite(&event_notifier
->priv
->parent
.u
.uprobe
, callsite
,
260 lttng_uprobes_event_notifier_handler_pre
, event_notifier
);
262 EXPORT_SYMBOL_GPL(lttng_uprobes_event_notifier_add_callsite
);
265 int lttng_uprobes_register(struct lttng_uprobe
*uprobe
, int fd
)
270 inode
= get_inode_from_fd(fd
);
272 printk(KERN_WARNING
"LTTng: Cannot get inode from fd\n");
276 uprobe
->inode
= inode
;
277 INIT_LIST_HEAD(&uprobe
->head
);
283 int lttng_uprobes_register_event(const char *name
, int fd
, struct lttng_kernel_event_recorder
*event_recorder
)
287 ret
= lttng_create_uprobe_event(name
, event_recorder
);
291 ret
= lttng_uprobes_register(&event_recorder
->priv
->parent
.u
.uprobe
, fd
);
298 kfree(event_recorder
->priv
->parent
.desc
->event_name
);
299 kfree(event_recorder
->priv
->parent
.desc
);
303 EXPORT_SYMBOL_GPL(lttng_uprobes_register_event
);
305 int lttng_uprobes_register_event_notifier(const char *name
, int fd
,
306 struct lttng_kernel_event_notifier
*event_notifier
)
310 ret
= lttng_create_uprobe_event_notifier(name
, event_notifier
);
314 ret
= lttng_uprobes_register(&event_notifier
->priv
->parent
.u
.uprobe
, fd
);
321 kfree(event_notifier
->priv
->parent
.desc
->event_name
);
322 kfree(event_notifier
->priv
->parent
.desc
);
326 EXPORT_SYMBOL_GPL(lttng_uprobes_register_event_notifier
);
329 void lttng_uprobes_unregister(struct inode
*inode
, struct list_head
*head
)
331 struct lttng_uprobe_handler
*iter
, *tmp
;
334 * Iterate over the list of handler, remove each handler from the list
335 * and free the struct.
337 list_for_each_entry_safe(iter
, tmp
, head
, node
) {
338 wrapper_uprobe_unregister(inode
, iter
->offset
, &iter
->up_consumer
);
339 list_del(&iter
->node
);
345 void lttng_uprobes_unregister_event(struct lttng_kernel_event_recorder
*event_recorder
)
347 lttng_uprobes_unregister(event_recorder
->priv
->parent
.u
.uprobe
.inode
, &event_recorder
->priv
->parent
.u
.uprobe
.head
);
349 EXPORT_SYMBOL_GPL(lttng_uprobes_unregister_event
);
351 void lttng_uprobes_unregister_event_notifier(struct lttng_kernel_event_notifier
*event_notifier
)
353 lttng_uprobes_unregister(event_notifier
->priv
->parent
.u
.uprobe
.inode
, &event_notifier
->priv
->parent
.u
.uprobe
.head
);
355 EXPORT_SYMBOL_GPL(lttng_uprobes_unregister_event_notifier
);
357 void lttng_uprobes_destroy_event_private(struct lttng_kernel_event_recorder
*event_recorder
)
359 iput(event_recorder
->priv
->parent
.u
.uprobe
.inode
);
360 kfree(event_recorder
->priv
->parent
.desc
->fields
[0]);
361 kfree(event_recorder
->priv
->parent
.desc
->fields
);
362 kfree(event_recorder
->priv
->parent
.desc
->event_name
);
363 kfree(event_recorder
->priv
->parent
.desc
);
365 EXPORT_SYMBOL_GPL(lttng_uprobes_destroy_event_private
);
367 void lttng_uprobes_destroy_event_notifier_private(struct lttng_kernel_event_notifier
*event_notifier
)
369 iput(event_notifier
->priv
->parent
.u
.uprobe
.inode
);
370 kfree(event_notifier
->priv
->parent
.desc
->event_name
);
371 kfree(event_notifier
->priv
->parent
.desc
);
373 EXPORT_SYMBOL_GPL(lttng_uprobes_destroy_event_notifier_private
);
375 MODULE_LICENSE("GPL and additional rights");
376 MODULE_AUTHOR("Yannick Brosseau");
377 MODULE_DESCRIPTION("Linux Trace Toolkit Uprobes Support");