Commit | Line | Data |
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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 | ||
437d5aa5 MD |
82 | static const struct lttng_kernel_type_common *event_type = |
83 | lttng_kernel_static_type_integer_from_type(unsigned long, __BYTE_ORDER, 16); | |
84 | ||
149b9a9d YB |
85 | /* |
86 | * Create event description. | |
87 | */ | |
88 | static | |
89 | int lttng_create_uprobe_event(const char *name, struct lttng_event *event) | |
90 | { | |
437d5aa5 MD |
91 | const struct lttng_kernel_event_field **fieldp_array; |
92 | struct lttng_kernel_event_field *field; | |
93 | struct lttng_kernel_event_desc *desc; | |
149b9a9d YB |
94 | int ret; |
95 | ||
437d5aa5 | 96 | desc = kzalloc(sizeof(*desc), GFP_KERNEL); |
149b9a9d YB |
97 | if (!desc) |
98 | return -ENOMEM; | |
437d5aa5 MD |
99 | desc->event_name = kstrdup(name, GFP_KERNEL); |
100 | if (!desc->event_name) { | |
149b9a9d YB |
101 | ret = -ENOMEM; |
102 | goto error_str; | |
103 | } | |
149b9a9d | 104 | desc->nr_fields = 1; |
437d5aa5 MD |
105 | fieldp_array = kzalloc(1 * sizeof(struct lttng_kernel_event_field *), GFP_KERNEL); |
106 | if (!fieldp_array) { | |
149b9a9d | 107 | ret = -ENOMEM; |
437d5aa5 | 108 | goto error_fieldp_array; |
149b9a9d | 109 | } |
437d5aa5 MD |
110 | desc->fields = fieldp_array; |
111 | desc->fields[0] = field = | |
112 | kzalloc(sizeof(struct lttng_kernel_event_field), GFP_KERNEL); | |
113 | if (!field) { | |
114 | ret = -ENOMEM; | |
115 | goto error_field; | |
116 | } | |
117 | field->name = "ip"; | |
118 | field->type = event_type; | |
149b9a9d YB |
119 | desc->owner = THIS_MODULE; |
120 | event->desc = desc; | |
121 | ||
122 | return 0; | |
123 | ||
437d5aa5 MD |
124 | error_field: |
125 | kfree(fieldp_array); | |
126 | error_fieldp_array: | |
127 | kfree(desc->event_name); | |
149b9a9d YB |
128 | error_str: |
129 | kfree(desc); | |
130 | return ret; | |
131 | } | |
132 | ||
9de67196 FD |
133 | /* |
134 | * Create event_notifier description. | |
135 | */ | |
136 | static | |
137 | int lttng_create_uprobe_event_notifier(const char *name, struct lttng_event_notifier *event_notifier) | |
138 | { | |
437d5aa5 | 139 | struct lttng_kernel_event_desc *desc; |
9de67196 FD |
140 | int ret; |
141 | ||
437d5aa5 | 142 | desc = kzalloc(sizeof(*desc), GFP_KERNEL); |
9de67196 FD |
143 | if (!desc) |
144 | return -ENOMEM; | |
437d5aa5 MD |
145 | desc->event_name = kstrdup(name, GFP_KERNEL); |
146 | if (!desc->event_name) { | |
9de67196 FD |
147 | ret = -ENOMEM; |
148 | goto error_str; | |
149 | } | |
150 | ||
151 | desc->nr_fields = 0; | |
152 | ||
153 | desc->owner = THIS_MODULE; | |
154 | event_notifier->desc = desc; | |
155 | ||
156 | return 0; | |
157 | ||
158 | error_str: | |
159 | kfree(desc); | |
160 | return ret; | |
161 | } | |
162 | ||
56377c91 FD |
163 | /* |
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 | |
166 | * iput(). | |
167 | */ | |
168 | static struct inode *get_inode_from_fd(int fd) | |
169 | { | |
170 | struct file *file; | |
171 | struct inode *inode; | |
172 | ||
173 | rcu_read_lock(); | |
174 | /* | |
175 | * Returns the file backing the given fd. Needs to be done inside an RCU | |
176 | * critical section. | |
177 | */ | |
0aebcd68 | 178 | file = lttng_lookup_fd_rcu(fd); |
56377c91 | 179 | if (file == NULL) { |
5a15f70c | 180 | printk(KERN_WARNING "LTTng: Cannot access file backing the fd(%d)\n", fd); |
56377c91 FD |
181 | inode = NULL; |
182 | goto error; | |
183 | } | |
184 | ||
185 | /* Grab a reference on the inode. */ | |
186 | inode = igrab(file->f_path.dentry->d_inode); | |
187 | if (inode == NULL) | |
5a15f70c | 188 | printk(KERN_WARNING "LTTng: Cannot grab a reference on the inode.\n"); |
56377c91 FD |
189 | error: |
190 | rcu_read_unlock(); | |
191 | return inode; | |
192 | } | |
193 | ||
83b802dc FD |
194 | |
195 | static | |
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), | |
199 | void *priv_data) | |
149b9a9d | 200 | { |
3aed4dca FD |
201 | int ret = 0; |
202 | struct lttng_uprobe_handler *uprobe_handler; | |
203 | ||
83b802dc | 204 | if (!priv_data) { |
3aed4dca FD |
205 | ret = -EINVAL; |
206 | goto end; | |
207 | } | |
208 | ||
209 | uprobe_handler = kzalloc(sizeof(struct lttng_uprobe_handler), GFP_KERNEL); | |
210 | if (!uprobe_handler) { | |
5a15f70c | 211 | printk(KERN_WARNING "LTTng: Error allocating uprobe_handler"); |
3aed4dca FD |
212 | ret = -ENOMEM; |
213 | goto end; | |
214 | } | |
215 | ||
196bfc6a | 216 | /* Ensure the memory we just allocated don't notify page faults. */ |
263b6c88 | 217 | wrapper_vmalloc_sync_mappings(); |
3aed4dca | 218 | |
83b802dc FD |
219 | uprobe_handler->u.event = priv_data; |
220 | uprobe_handler->up_consumer.handler = handler; | |
3aed4dca FD |
221 | |
222 | ret = copy_from_user(&uprobe_handler->offset, &callsite->u.uprobe.offset, sizeof(uint64_t)); | |
223 | if (ret) { | |
224 | goto register_error; | |
225 | } | |
226 | ||
83b802dc | 227 | ret = wrapper_uprobe_register(uprobe->inode, |
3aed4dca FD |
228 | uprobe_handler->offset, &uprobe_handler->up_consumer); |
229 | if (ret) { | |
5a15f70c | 230 | printk(KERN_WARNING "LTTng: Error registering probe on inode %lu " |
83b802dc | 231 | "and offset 0x%llx\n", uprobe->inode->i_ino, |
3aed4dca FD |
232 | uprobe_handler->offset); |
233 | ret = -1; | |
234 | goto register_error; | |
235 | } | |
236 | ||
83b802dc | 237 | list_add(&uprobe_handler->node, &uprobe->head); |
3aed4dca FD |
238 | |
239 | return ret; | |
240 | ||
241 | register_error: | |
242 | kfree(uprobe_handler); | |
243 | end: | |
244 | return ret; | |
245 | } | |
3aed4dca | 246 | |
83b802dc FD |
247 | int lttng_uprobes_event_add_callsite(struct lttng_event *event, |
248 | struct lttng_kernel_event_callsite __user *callsite) | |
249 | { | |
250 | return lttng_uprobes_add_callsite(&event->u.uprobe, callsite, | |
251 | lttng_uprobes_event_handler_pre, event); | |
252 | } | |
253 | EXPORT_SYMBOL_GPL(lttng_uprobes_event_add_callsite); | |
254 | ||
9de67196 FD |
255 | int lttng_uprobes_event_notifier_add_callsite(struct lttng_event_notifier *event_notifier, |
256 | struct lttng_kernel_event_callsite __user *callsite) | |
257 | { | |
258 | return lttng_uprobes_add_callsite(&event_notifier->u.uprobe, callsite, | |
259 | lttng_uprobes_event_notifier_handler_pre, event_notifier); | |
260 | } | |
261 | EXPORT_SYMBOL_GPL(lttng_uprobes_event_notifier_add_callsite); | |
262 | ||
83b802dc FD |
263 | static |
264 | int lttng_uprobes_register(struct lttng_uprobe *uprobe, int fd) | |
3aed4dca FD |
265 | { |
266 | int ret = 0; | |
56377c91 | 267 | struct inode *inode; |
149b9a9d | 268 | |
56377c91 FD |
269 | inode = get_inode_from_fd(fd); |
270 | if (!inode) { | |
5a15f70c | 271 | printk(KERN_WARNING "LTTng: Cannot get inode from fd\n"); |
56377c91 FD |
272 | ret = -EBADF; |
273 | goto inode_error; | |
274 | } | |
83b802dc FD |
275 | uprobe->inode = inode; |
276 | INIT_LIST_HEAD(&uprobe->head); | |
277 | ||
278 | inode_error: | |
279 | return ret; | |
280 | } | |
281 | ||
282 | int lttng_uprobes_register_event(const char *name, int fd, struct lttng_event *event) | |
283 | { | |
284 | int ret = 0; | |
285 | ||
286 | ret = lttng_create_uprobe_event(name, event); | |
287 | if (ret) | |
288 | goto error; | |
289 | ||
290 | ret = lttng_uprobes_register(&event->u.uprobe, fd); | |
291 | if (ret) | |
292 | goto register_error; | |
149b9a9d | 293 | |
149b9a9d YB |
294 | return 0; |
295 | ||
83b802dc | 296 | register_error: |
437d5aa5 | 297 | kfree(event->desc->event_name); |
149b9a9d YB |
298 | kfree(event->desc); |
299 | error: | |
300 | return ret; | |
301 | } | |
83b802dc | 302 | EXPORT_SYMBOL_GPL(lttng_uprobes_register_event); |
149b9a9d | 303 | |
9de67196 FD |
304 | int lttng_uprobes_register_event_notifier(const char *name, int fd, |
305 | struct lttng_event_notifier *event_notifier) | |
306 | { | |
307 | int ret = 0; | |
308 | ||
309 | ret = lttng_create_uprobe_event_notifier(name, event_notifier); | |
310 | if (ret) | |
311 | goto error; | |
312 | ||
313 | ret = lttng_uprobes_register(&event_notifier->u.uprobe, fd); | |
314 | if (ret) | |
315 | goto register_error; | |
316 | ||
317 | return 0; | |
318 | ||
319 | register_error: | |
437d5aa5 | 320 | kfree(event_notifier->desc->event_name); |
9de67196 FD |
321 | kfree(event_notifier->desc); |
322 | error: | |
323 | return ret; | |
324 | } | |
325 | EXPORT_SYMBOL_GPL(lttng_uprobes_register_event_notifier); | |
326 | ||
327 | static | |
328 | void lttng_uprobes_unregister(struct inode *inode, struct list_head *head) | |
149b9a9d | 329 | { |
3aed4dca FD |
330 | struct lttng_uprobe_handler *iter, *tmp; |
331 | ||
332 | /* | |
333 | * Iterate over the list of handler, remove each handler from the list | |
334 | * and free the struct. | |
335 | */ | |
9de67196 FD |
336 | list_for_each_entry_safe(iter, tmp, head, node) { |
337 | wrapper_uprobe_unregister(inode, iter->offset, &iter->up_consumer); | |
3aed4dca FD |
338 | list_del(&iter->node); |
339 | kfree(iter); | |
340 | } | |
9de67196 FD |
341 | |
342 | } | |
343 | ||
344 | void lttng_uprobes_unregister_event(struct lttng_event *event) | |
345 | { | |
346 | lttng_uprobes_unregister(event->u.uprobe.inode, &event->u.uprobe.head); | |
149b9a9d | 347 | } |
83b802dc | 348 | EXPORT_SYMBOL_GPL(lttng_uprobes_unregister_event); |
149b9a9d | 349 | |
9de67196 FD |
350 | void lttng_uprobes_unregister_event_notifier(struct lttng_event_notifier *event_notifier) |
351 | { | |
352 | lttng_uprobes_unregister(event_notifier->u.uprobe.inode, &event_notifier->u.uprobe.head); | |
353 | } | |
354 | EXPORT_SYMBOL_GPL(lttng_uprobes_unregister_event_notifier); | |
355 | ||
83b802dc | 356 | void lttng_uprobes_destroy_event_private(struct lttng_event *event) |
149b9a9d YB |
357 | { |
358 | iput(event->u.uprobe.inode); | |
437d5aa5 MD |
359 | kfree(event->desc->fields[0]); |
360 | kfree(event->desc->fields); | |
361 | kfree(event->desc->event_name); | |
149b9a9d YB |
362 | kfree(event->desc); |
363 | } | |
83b802dc | 364 | EXPORT_SYMBOL_GPL(lttng_uprobes_destroy_event_private); |
149b9a9d | 365 | |
9de67196 FD |
366 | void lttng_uprobes_destroy_event_notifier_private(struct lttng_event_notifier *event_notifier) |
367 | { | |
368 | iput(event_notifier->u.uprobe.inode); | |
437d5aa5 | 369 | kfree(event_notifier->desc->event_name); |
9de67196 FD |
370 | kfree(event_notifier->desc); |
371 | } | |
372 | EXPORT_SYMBOL_GPL(lttng_uprobes_destroy_event_notifier_private); | |
373 | ||
149b9a9d YB |
374 | MODULE_LICENSE("GPL and additional rights"); |
375 | MODULE_AUTHOR("Yannick Brosseau"); | |
376 | MODULE_DESCRIPTION("Linux Trace Toolkit Uprobes Support"); |