Commit | Line | Data |
---|---|---|
b7cdc182 | 1 | /* SPDX-License-Identifier: (GPL-2.0-only OR LGPL-2.1-only) |
8134eb60 | 2 | * |
149b9a9d YB |
3 | * probes/lttng-uprobes.c |
4 | * | |
5 | * LTTng uprobes integration module. | |
6 | * | |
7 | * Copyright (C) 2013 Yannick Brosseau <yannick.brosseau@gmail.com> | |
8 | * Copyright (C) 2009-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com> | |
9 | * | |
149b9a9d YB |
10 | */ |
11 | ||
0aebcd68 | 12 | #include <wrapper/fdtable.h> |
3aed4dca | 13 | #include <linux/list.h> |
149b9a9d YB |
14 | #include <linux/module.h> |
15 | #include <linux/namei.h> | |
16 | #include <linux/slab.h> | |
3aed4dca | 17 | #include <linux/uaccess.h> |
2df37e95 MD |
18 | #include <lttng/events.h> |
19 | #include <lttng/tracer.h> | |
149b9a9d | 20 | #include <wrapper/irqflags.h> |
24591303 | 21 | #include <ringbuffer/frontend_types.h> |
149b9a9d YB |
22 | #include <wrapper/uprobes.h> |
23 | #include <wrapper/vmalloc.h> | |
24 | ||
25 | static | |
83b802dc | 26 | int lttng_uprobes_event_handler_pre(struct uprobe_consumer *uc, struct pt_regs *regs) |
149b9a9d | 27 | { |
3aed4dca FD |
28 | struct lttng_uprobe_handler *uprobe_handler = |
29 | container_of(uc, struct lttng_uprobe_handler, up_consumer); | |
83b802dc | 30 | struct lttng_event *event = uprobe_handler->u.event; |
149b9a9d YB |
31 | struct lttng_probe_ctx lttng_probe_ctx = { |
32 | .event = event, | |
33 | .interruptible = !lttng_regs_irqs_disabled(regs), | |
34 | }; | |
35 | struct lttng_channel *chan = event->chan; | |
36 | struct lib_ring_buffer_ctx ctx; | |
37 | int ret; | |
38 | ||
39 | struct { | |
40 | unsigned long ip; | |
56377c91 | 41 | } payload; |
149b9a9d | 42 | |
585e5dcc | 43 | if (unlikely(!LTTNG_READ_ONCE(chan->session->active))) |
149b9a9d | 44 | return 0; |
585e5dcc | 45 | if (unlikely(!LTTNG_READ_ONCE(chan->enabled))) |
149b9a9d | 46 | return 0; |
585e5dcc | 47 | if (unlikely(!LTTNG_READ_ONCE(event->enabled))) |
149b9a9d YB |
48 | return 0; |
49 | ||
50 | lib_ring_buffer_ctx_init(&ctx, chan->chan, <tng_probe_ctx, | |
51 | sizeof(payload), lttng_alignof(payload), -1); | |
52 | ||
53 | ret = chan->ops->event_reserve(&ctx, event->id); | |
54 | if (ret < 0) | |
55 | return 0; | |
56 | ||
57 | /* Event payload. */ | |
7445d54f | 58 | payload.ip = (unsigned long)instruction_pointer(regs); |
56377c91 | 59 | |
149b9a9d YB |
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); | |
63 | return 0; | |
64 | } | |
65 | ||
9de67196 FD |
66 | static |
67 | int lttng_uprobes_event_notifier_handler_pre(struct uprobe_consumer *uc, struct pt_regs *regs) | |
68 | { | |
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; | |
c3eddb2e | 72 | struct lttng_kernel_notifier_ctx notif_ctx; |
9de67196 FD |
73 | |
74 | if (unlikely(!READ_ONCE(event_notifier->enabled))) | |
75 | return 0; | |
76 | ||
c3eddb2e MD |
77 | notif_ctx.eval_capture = LTTNG_READ_ONCE(event_notifier->eval_capture); |
78 | event_notifier->send_notification(event_notifier, NULL, NULL, ¬if_ctx); | |
9de67196 FD |
79 | return 0; |
80 | } | |
81 | ||
149b9a9d YB |
82 | /* |
83 | * Create event description. | |
84 | */ | |
85 | static | |
86 | int lttng_create_uprobe_event(const char *name, struct lttng_event *event) | |
87 | { | |
88 | struct lttng_event_desc *desc; | |
89 | struct lttng_event_field *fields; | |
90 | int ret; | |
91 | ||
92 | desc = kzalloc(sizeof(*event->desc), GFP_KERNEL); | |
93 | if (!desc) | |
94 | return -ENOMEM; | |
95 | desc->name = kstrdup(name, GFP_KERNEL); | |
96 | if (!desc->name) { | |
97 | ret = -ENOMEM; | |
98 | goto error_str; | |
99 | } | |
100 | ||
101 | desc->nr_fields = 1; | |
102 | desc->fields = fields = | |
103 | kzalloc(1 * sizeof(struct lttng_event_field), GFP_KERNEL); | |
104 | ||
105 | if (!desc->fields) { | |
106 | ret = -ENOMEM; | |
107 | goto error_fields; | |
108 | } | |
109 | fields[0].name = "ip"; | |
110 | fields[0].type.atype = atype_integer; | |
ceabb767 MD |
111 | fields[0].type.u.integer.size = sizeof(unsigned long) * CHAR_BIT; |
112 | fields[0].type.u.integer.alignment = lttng_alignof(unsigned long) * CHAR_BIT; | |
113 | fields[0].type.u.integer.signedness = lttng_is_signed_type(unsigned long); | |
114 | fields[0].type.u.integer.reverse_byte_order = 0; | |
115 | fields[0].type.u.integer.base = 16; | |
116 | fields[0].type.u.integer.encoding = lttng_encode_none; | |
149b9a9d YB |
117 | |
118 | desc->owner = THIS_MODULE; | |
119 | event->desc = desc; | |
120 | ||
121 | return 0; | |
122 | ||
123 | error_fields: | |
124 | kfree(desc->name); | |
125 | error_str: | |
126 | kfree(desc); | |
127 | return ret; | |
128 | } | |
129 | ||
9de67196 FD |
130 | /* |
131 | * Create event_notifier description. | |
132 | */ | |
133 | static | |
134 | int lttng_create_uprobe_event_notifier(const char *name, struct lttng_event_notifier *event_notifier) | |
135 | { | |
136 | struct lttng_event_desc *desc; | |
137 | int ret; | |
138 | ||
139 | desc = kzalloc(sizeof(*event_notifier->desc), GFP_KERNEL); | |
140 | if (!desc) | |
141 | return -ENOMEM; | |
142 | desc->name = kstrdup(name, GFP_KERNEL); | |
143 | if (!desc->name) { | |
144 | ret = -ENOMEM; | |
145 | goto error_str; | |
146 | } | |
147 | ||
148 | desc->nr_fields = 0; | |
149 | ||
150 | desc->owner = THIS_MODULE; | |
151 | event_notifier->desc = desc; | |
152 | ||
153 | return 0; | |
154 | ||
155 | error_str: | |
156 | kfree(desc); | |
157 | return ret; | |
158 | } | |
159 | ||
56377c91 FD |
160 | /* |
161 | * Returns the inode struct from the current task and an fd. The inode is | |
162 | * grabbed by this function and must be put once we are done with it using | |
163 | * iput(). | |
164 | */ | |
165 | static struct inode *get_inode_from_fd(int fd) | |
166 | { | |
167 | struct file *file; | |
168 | struct inode *inode; | |
169 | ||
170 | rcu_read_lock(); | |
171 | /* | |
172 | * Returns the file backing the given fd. Needs to be done inside an RCU | |
173 | * critical section. | |
174 | */ | |
0aebcd68 | 175 | file = lttng_lookup_fd_rcu(fd); |
56377c91 | 176 | if (file == NULL) { |
5a15f70c | 177 | printk(KERN_WARNING "LTTng: Cannot access file backing the fd(%d)\n", fd); |
56377c91 FD |
178 | inode = NULL; |
179 | goto error; | |
180 | } | |
181 | ||
182 | /* Grab a reference on the inode. */ | |
183 | inode = igrab(file->f_path.dentry->d_inode); | |
184 | if (inode == NULL) | |
5a15f70c | 185 | printk(KERN_WARNING "LTTng: Cannot grab a reference on the inode.\n"); |
56377c91 FD |
186 | error: |
187 | rcu_read_unlock(); | |
188 | return inode; | |
189 | } | |
190 | ||
83b802dc FD |
191 | |
192 | static | |
193 | int lttng_uprobes_add_callsite(struct lttng_uprobe *uprobe, | |
194 | struct lttng_kernel_event_callsite __user *callsite, | |
195 | int (*handler)(struct uprobe_consumer *self, struct pt_regs *regs), | |
196 | void *priv_data) | |
149b9a9d | 197 | { |
3aed4dca FD |
198 | int ret = 0; |
199 | struct lttng_uprobe_handler *uprobe_handler; | |
200 | ||
83b802dc | 201 | if (!priv_data) { |
3aed4dca FD |
202 | ret = -EINVAL; |
203 | goto end; | |
204 | } | |
205 | ||
206 | uprobe_handler = kzalloc(sizeof(struct lttng_uprobe_handler), GFP_KERNEL); | |
207 | if (!uprobe_handler) { | |
5a15f70c | 208 | printk(KERN_WARNING "LTTng: Error allocating uprobe_handler"); |
3aed4dca FD |
209 | ret = -ENOMEM; |
210 | goto end; | |
211 | } | |
212 | ||
196bfc6a | 213 | /* Ensure the memory we just allocated don't notify page faults. */ |
263b6c88 | 214 | wrapper_vmalloc_sync_mappings(); |
3aed4dca | 215 | |
83b802dc FD |
216 | uprobe_handler->u.event = priv_data; |
217 | uprobe_handler->up_consumer.handler = handler; | |
3aed4dca FD |
218 | |
219 | ret = copy_from_user(&uprobe_handler->offset, &callsite->u.uprobe.offset, sizeof(uint64_t)); | |
220 | if (ret) { | |
221 | goto register_error; | |
222 | } | |
223 | ||
83b802dc | 224 | ret = wrapper_uprobe_register(uprobe->inode, |
3aed4dca FD |
225 | uprobe_handler->offset, &uprobe_handler->up_consumer); |
226 | if (ret) { | |
5a15f70c | 227 | printk(KERN_WARNING "LTTng: Error registering probe on inode %lu " |
83b802dc | 228 | "and offset 0x%llx\n", uprobe->inode->i_ino, |
3aed4dca FD |
229 | uprobe_handler->offset); |
230 | ret = -1; | |
231 | goto register_error; | |
232 | } | |
233 | ||
83b802dc | 234 | list_add(&uprobe_handler->node, &uprobe->head); |
3aed4dca FD |
235 | |
236 | return ret; | |
237 | ||
238 | register_error: | |
239 | kfree(uprobe_handler); | |
240 | end: | |
241 | return ret; | |
242 | } | |
3aed4dca | 243 | |
83b802dc FD |
244 | int lttng_uprobes_event_add_callsite(struct lttng_event *event, |
245 | struct lttng_kernel_event_callsite __user *callsite) | |
246 | { | |
247 | return lttng_uprobes_add_callsite(&event->u.uprobe, callsite, | |
248 | lttng_uprobes_event_handler_pre, event); | |
249 | } | |
250 | EXPORT_SYMBOL_GPL(lttng_uprobes_event_add_callsite); | |
251 | ||
9de67196 FD |
252 | int lttng_uprobes_event_notifier_add_callsite(struct lttng_event_notifier *event_notifier, |
253 | struct lttng_kernel_event_callsite __user *callsite) | |
254 | { | |
255 | return lttng_uprobes_add_callsite(&event_notifier->u.uprobe, callsite, | |
256 | lttng_uprobes_event_notifier_handler_pre, event_notifier); | |
257 | } | |
258 | EXPORT_SYMBOL_GPL(lttng_uprobes_event_notifier_add_callsite); | |
259 | ||
83b802dc FD |
260 | static |
261 | int lttng_uprobes_register(struct lttng_uprobe *uprobe, int fd) | |
3aed4dca FD |
262 | { |
263 | int ret = 0; | |
56377c91 | 264 | struct inode *inode; |
149b9a9d | 265 | |
56377c91 FD |
266 | inode = get_inode_from_fd(fd); |
267 | if (!inode) { | |
5a15f70c | 268 | printk(KERN_WARNING "LTTng: Cannot get inode from fd\n"); |
56377c91 FD |
269 | ret = -EBADF; |
270 | goto inode_error; | |
271 | } | |
83b802dc FD |
272 | uprobe->inode = inode; |
273 | INIT_LIST_HEAD(&uprobe->head); | |
274 | ||
275 | inode_error: | |
276 | return ret; | |
277 | } | |
278 | ||
279 | int lttng_uprobes_register_event(const char *name, int fd, struct lttng_event *event) | |
280 | { | |
281 | int ret = 0; | |
282 | ||
283 | ret = lttng_create_uprobe_event(name, event); | |
284 | if (ret) | |
285 | goto error; | |
286 | ||
287 | ret = lttng_uprobes_register(&event->u.uprobe, fd); | |
288 | if (ret) | |
289 | goto register_error; | |
149b9a9d | 290 | |
149b9a9d YB |
291 | return 0; |
292 | ||
83b802dc | 293 | register_error: |
149b9a9d YB |
294 | kfree(event->desc->name); |
295 | kfree(event->desc); | |
296 | error: | |
297 | return ret; | |
298 | } | |
83b802dc | 299 | EXPORT_SYMBOL_GPL(lttng_uprobes_register_event); |
149b9a9d | 300 | |
9de67196 FD |
301 | int lttng_uprobes_register_event_notifier(const char *name, int fd, |
302 | struct lttng_event_notifier *event_notifier) | |
303 | { | |
304 | int ret = 0; | |
305 | ||
306 | ret = lttng_create_uprobe_event_notifier(name, event_notifier); | |
307 | if (ret) | |
308 | goto error; | |
309 | ||
310 | ret = lttng_uprobes_register(&event_notifier->u.uprobe, fd); | |
311 | if (ret) | |
312 | goto register_error; | |
313 | ||
314 | return 0; | |
315 | ||
316 | register_error: | |
317 | kfree(event_notifier->desc->name); | |
318 | kfree(event_notifier->desc); | |
319 | error: | |
320 | return ret; | |
321 | } | |
322 | EXPORT_SYMBOL_GPL(lttng_uprobes_register_event_notifier); | |
323 | ||
324 | static | |
325 | void lttng_uprobes_unregister(struct inode *inode, struct list_head *head) | |
149b9a9d | 326 | { |
3aed4dca FD |
327 | struct lttng_uprobe_handler *iter, *tmp; |
328 | ||
329 | /* | |
330 | * Iterate over the list of handler, remove each handler from the list | |
331 | * and free the struct. | |
332 | */ | |
9de67196 FD |
333 | list_for_each_entry_safe(iter, tmp, head, node) { |
334 | wrapper_uprobe_unregister(inode, iter->offset, &iter->up_consumer); | |
3aed4dca FD |
335 | list_del(&iter->node); |
336 | kfree(iter); | |
337 | } | |
9de67196 FD |
338 | |
339 | } | |
340 | ||
341 | void lttng_uprobes_unregister_event(struct lttng_event *event) | |
342 | { | |
343 | lttng_uprobes_unregister(event->u.uprobe.inode, &event->u.uprobe.head); | |
149b9a9d | 344 | } |
83b802dc | 345 | EXPORT_SYMBOL_GPL(lttng_uprobes_unregister_event); |
149b9a9d | 346 | |
9de67196 FD |
347 | void lttng_uprobes_unregister_event_notifier(struct lttng_event_notifier *event_notifier) |
348 | { | |
349 | lttng_uprobes_unregister(event_notifier->u.uprobe.inode, &event_notifier->u.uprobe.head); | |
350 | } | |
351 | EXPORT_SYMBOL_GPL(lttng_uprobes_unregister_event_notifier); | |
352 | ||
83b802dc | 353 | void lttng_uprobes_destroy_event_private(struct lttng_event *event) |
149b9a9d YB |
354 | { |
355 | iput(event->u.uprobe.inode); | |
356 | kfree(event->desc->name); | |
357 | kfree(event->desc); | |
358 | } | |
83b802dc | 359 | EXPORT_SYMBOL_GPL(lttng_uprobes_destroy_event_private); |
149b9a9d | 360 | |
9de67196 FD |
361 | void lttng_uprobes_destroy_event_notifier_private(struct lttng_event_notifier *event_notifier) |
362 | { | |
363 | iput(event_notifier->u.uprobe.inode); | |
364 | kfree(event_notifier->desc->name); | |
365 | kfree(event_notifier->desc); | |
366 | } | |
367 | EXPORT_SYMBOL_GPL(lttng_uprobes_destroy_event_notifier_private); | |
368 | ||
149b9a9d YB |
369 | MODULE_LICENSE("GPL and additional rights"); |
370 | MODULE_AUTHOR("Yannick Brosseau"); | |
371 | MODULE_DESCRIPTION("Linux Trace Toolkit Uprobes Support"); |