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 | 18 | #include <lttng/events.h> |
a67ba386 | 19 | #include <lttng/events-internal.h> |
2df37e95 | 20 | #include <lttng/tracer.h> |
149b9a9d | 21 | #include <wrapper/irqflags.h> |
24591303 | 22 | #include <ringbuffer/frontend_types.h> |
149b9a9d YB |
23 | #include <wrapper/uprobes.h> |
24 | #include <wrapper/vmalloc.h> | |
25 | ||
26 | static | |
83b802dc | 27 | int lttng_uprobes_event_handler_pre(struct uprobe_consumer *uc, struct pt_regs *regs) |
149b9a9d | 28 | { |
3aed4dca FD |
29 | struct lttng_uprobe_handler *uprobe_handler = |
30 | container_of(uc, struct lttng_uprobe_handler, up_consumer); | |
e2d5dbc7 | 31 | struct lttng_kernel_event_common *event = uprobe_handler->event; |
346cb5ee | 32 | struct lttng_kernel_probe_ctx lttng_probe_ctx = { |
e2d5dbc7 | 33 | .event = event, |
149b9a9d YB |
34 | .interruptible = !lttng_regs_irqs_disabled(regs), |
35 | }; | |
149b9a9d YB |
36 | struct { |
37 | unsigned long ip; | |
56377c91 | 38 | } payload; |
149b9a9d | 39 | |
e2d5dbc7 MD |
40 | switch (event->type) { |
41 | case LTTNG_KERNEL_EVENT_TYPE_RECORDER: | |
42 | { | |
43 | struct lttng_kernel_event_recorder *event_recorder = | |
44 | container_of(event, struct lttng_kernel_event_recorder, parent); | |
45 | struct lttng_channel *chan = event_recorder->chan; | |
46 | ||
47 | if (unlikely(!LTTNG_READ_ONCE(chan->session->active))) | |
48 | return 0; | |
49 | if (unlikely(!LTTNG_READ_ONCE(chan->enabled))) | |
50 | return 0; | |
51 | break; | |
52 | } | |
53 | case LTTNG_KERNEL_EVENT_TYPE_NOTIFIER: | |
54 | break; | |
55 | default: | |
56 | WARN_ON_ONCE(1); | |
57 | } | |
9de67196 | 58 | |
e2d5dbc7 | 59 | if (unlikely(!LTTNG_READ_ONCE(event->enabled))) |
9de67196 FD |
60 | return 0; |
61 | ||
e2d5dbc7 MD |
62 | switch (event->type) { |
63 | case LTTNG_KERNEL_EVENT_TYPE_RECORDER: | |
64 | { | |
65 | struct lttng_kernel_event_recorder *event_recorder = | |
66 | container_of(event, struct lttng_kernel_event_recorder, parent); | |
67 | struct lttng_channel *chan = event_recorder->chan; | |
68 | struct lib_ring_buffer_ctx ctx; | |
69 | int ret; | |
70 | ||
c7d9db61 MD |
71 | lib_ring_buffer_ctx_init(&ctx, event_recorder, |
72 | sizeof(payload), lttng_alignof(payload), <tng_probe_ctx); | |
e2d5dbc7 | 73 | |
cefd899f | 74 | ret = chan->ops->event_reserve(&ctx); |
e2d5dbc7 MD |
75 | if (ret < 0) |
76 | return 0; | |
77 | ||
78 | /* Event payload. */ | |
79 | payload.ip = (unsigned long)instruction_pointer(regs); | |
80 | ||
81 | lib_ring_buffer_align_ctx(&ctx, lttng_alignof(payload)); | |
82 | chan->ops->event_write(&ctx, &payload, sizeof(payload)); | |
83 | chan->ops->event_commit(&ctx); | |
84 | break; | |
85 | } | |
86 | case LTTNG_KERNEL_EVENT_TYPE_NOTIFIER: | |
87 | { | |
88 | struct lttng_kernel_event_notifier *event_notifier = | |
89 | container_of(event, struct lttng_kernel_event_notifier, parent); | |
90 | struct lttng_kernel_notification_ctx notif_ctx; | |
91 | ||
92 | notif_ctx.eval_capture = LTTNG_READ_ONCE(event_notifier->eval_capture); | |
93 | event_notifier->notification_send(event_notifier, NULL, NULL, ¬if_ctx); | |
94 | break; | |
95 | } | |
96 | default: | |
97 | WARN_ON_ONCE(1); | |
98 | } | |
9de67196 FD |
99 | return 0; |
100 | } | |
101 | ||
437d5aa5 MD |
102 | static const struct lttng_kernel_type_common *event_type = |
103 | lttng_kernel_static_type_integer_from_type(unsigned long, __BYTE_ORDER, 16); | |
104 | ||
149b9a9d YB |
105 | /* |
106 | * Create event description. | |
107 | */ | |
108 | static | |
a67ba386 | 109 | int lttng_create_uprobe_event(const char *name, struct lttng_kernel_event_recorder *event_recorder) |
149b9a9d | 110 | { |
437d5aa5 MD |
111 | const struct lttng_kernel_event_field **fieldp_array; |
112 | struct lttng_kernel_event_field *field; | |
113 | struct lttng_kernel_event_desc *desc; | |
149b9a9d YB |
114 | int ret; |
115 | ||
437d5aa5 | 116 | desc = kzalloc(sizeof(*desc), GFP_KERNEL); |
149b9a9d YB |
117 | if (!desc) |
118 | return -ENOMEM; | |
437d5aa5 MD |
119 | desc->event_name = kstrdup(name, GFP_KERNEL); |
120 | if (!desc->event_name) { | |
149b9a9d YB |
121 | ret = -ENOMEM; |
122 | goto error_str; | |
123 | } | |
149b9a9d | 124 | desc->nr_fields = 1; |
437d5aa5 MD |
125 | fieldp_array = kzalloc(1 * sizeof(struct lttng_kernel_event_field *), GFP_KERNEL); |
126 | if (!fieldp_array) { | |
149b9a9d | 127 | ret = -ENOMEM; |
437d5aa5 | 128 | goto error_fieldp_array; |
149b9a9d | 129 | } |
437d5aa5 MD |
130 | desc->fields = fieldp_array; |
131 | desc->fields[0] = field = | |
132 | kzalloc(sizeof(struct lttng_kernel_event_field), GFP_KERNEL); | |
133 | if (!field) { | |
134 | ret = -ENOMEM; | |
135 | goto error_field; | |
136 | } | |
137 | field->name = "ip"; | |
138 | field->type = event_type; | |
149b9a9d | 139 | desc->owner = THIS_MODULE; |
a67ba386 | 140 | event_recorder->priv->parent.desc = desc; |
149b9a9d YB |
141 | |
142 | return 0; | |
143 | ||
437d5aa5 MD |
144 | error_field: |
145 | kfree(fieldp_array); | |
146 | error_fieldp_array: | |
147 | kfree(desc->event_name); | |
149b9a9d YB |
148 | error_str: |
149 | kfree(desc); | |
150 | return ret; | |
151 | } | |
152 | ||
9de67196 FD |
153 | /* |
154 | * Create event_notifier description. | |
155 | */ | |
156 | static | |
a67ba386 | 157 | int lttng_create_uprobe_event_notifier(const char *name, struct lttng_kernel_event_notifier *event_notifier) |
9de67196 | 158 | { |
437d5aa5 | 159 | struct lttng_kernel_event_desc *desc; |
9de67196 FD |
160 | int ret; |
161 | ||
437d5aa5 | 162 | desc = kzalloc(sizeof(*desc), GFP_KERNEL); |
9de67196 FD |
163 | if (!desc) |
164 | return -ENOMEM; | |
437d5aa5 MD |
165 | desc->event_name = kstrdup(name, GFP_KERNEL); |
166 | if (!desc->event_name) { | |
9de67196 FD |
167 | ret = -ENOMEM; |
168 | goto error_str; | |
169 | } | |
170 | ||
171 | desc->nr_fields = 0; | |
172 | ||
173 | desc->owner = THIS_MODULE; | |
a67ba386 | 174 | event_notifier->priv->parent.desc = desc; |
9de67196 FD |
175 | |
176 | return 0; | |
177 | ||
178 | error_str: | |
179 | kfree(desc); | |
180 | return ret; | |
181 | } | |
182 | ||
56377c91 FD |
183 | /* |
184 | * Returns the inode struct from the current task and an fd. The inode is | |
185 | * grabbed by this function and must be put once we are done with it using | |
186 | * iput(). | |
187 | */ | |
188 | static struct inode *get_inode_from_fd(int fd) | |
189 | { | |
190 | struct file *file; | |
191 | struct inode *inode; | |
192 | ||
193 | rcu_read_lock(); | |
194 | /* | |
195 | * Returns the file backing the given fd. Needs to be done inside an RCU | |
196 | * critical section. | |
197 | */ | |
0aebcd68 | 198 | file = lttng_lookup_fd_rcu(fd); |
56377c91 | 199 | if (file == NULL) { |
5a15f70c | 200 | printk(KERN_WARNING "LTTng: Cannot access file backing the fd(%d)\n", fd); |
56377c91 FD |
201 | inode = NULL; |
202 | goto error; | |
203 | } | |
204 | ||
205 | /* Grab a reference on the inode. */ | |
206 | inode = igrab(file->f_path.dentry->d_inode); | |
207 | if (inode == NULL) | |
5a15f70c | 208 | printk(KERN_WARNING "LTTng: Cannot grab a reference on the inode.\n"); |
56377c91 FD |
209 | error: |
210 | rcu_read_unlock(); | |
211 | return inode; | |
212 | } | |
213 | ||
83b802dc FD |
214 | |
215 | static | |
216 | int lttng_uprobes_add_callsite(struct lttng_uprobe *uprobe, | |
606828e4 | 217 | struct lttng_kernel_abi_event_callsite __user *callsite, |
83b802dc FD |
218 | int (*handler)(struct uprobe_consumer *self, struct pt_regs *regs), |
219 | void *priv_data) | |
149b9a9d | 220 | { |
3aed4dca FD |
221 | int ret = 0; |
222 | struct lttng_uprobe_handler *uprobe_handler; | |
223 | ||
83b802dc | 224 | if (!priv_data) { |
3aed4dca FD |
225 | ret = -EINVAL; |
226 | goto end; | |
227 | } | |
228 | ||
229 | uprobe_handler = kzalloc(sizeof(struct lttng_uprobe_handler), GFP_KERNEL); | |
230 | if (!uprobe_handler) { | |
5a15f70c | 231 | printk(KERN_WARNING "LTTng: Error allocating uprobe_handler"); |
3aed4dca FD |
232 | ret = -ENOMEM; |
233 | goto end; | |
234 | } | |
235 | ||
196bfc6a | 236 | /* Ensure the memory we just allocated don't notify page faults. */ |
263b6c88 | 237 | wrapper_vmalloc_sync_mappings(); |
3aed4dca | 238 | |
e2d5dbc7 | 239 | uprobe_handler->event = priv_data; |
83b802dc | 240 | uprobe_handler->up_consumer.handler = handler; |
3aed4dca FD |
241 | |
242 | ret = copy_from_user(&uprobe_handler->offset, &callsite->u.uprobe.offset, sizeof(uint64_t)); | |
243 | if (ret) { | |
244 | goto register_error; | |
245 | } | |
246 | ||
83b802dc | 247 | ret = wrapper_uprobe_register(uprobe->inode, |
3aed4dca FD |
248 | uprobe_handler->offset, &uprobe_handler->up_consumer); |
249 | if (ret) { | |
5a15f70c | 250 | printk(KERN_WARNING "LTTng: Error registering probe on inode %lu " |
83b802dc | 251 | "and offset 0x%llx\n", uprobe->inode->i_ino, |
3aed4dca FD |
252 | uprobe_handler->offset); |
253 | ret = -1; | |
254 | goto register_error; | |
255 | } | |
256 | ||
83b802dc | 257 | list_add(&uprobe_handler->node, &uprobe->head); |
3aed4dca FD |
258 | |
259 | return ret; | |
260 | ||
261 | register_error: | |
262 | kfree(uprobe_handler); | |
263 | end: | |
264 | return ret; | |
265 | } | |
3aed4dca | 266 | |
e2d5dbc7 | 267 | int lttng_uprobes_event_add_callsite(struct lttng_kernel_event_common *event, |
606828e4 | 268 | struct lttng_kernel_abi_event_callsite __user *callsite) |
83b802dc | 269 | { |
e2d5dbc7 MD |
270 | return lttng_uprobes_add_callsite(&event->priv->u.uprobe, callsite, |
271 | lttng_uprobes_event_handler_pre, event); | |
83b802dc FD |
272 | } |
273 | EXPORT_SYMBOL_GPL(lttng_uprobes_event_add_callsite); | |
274 | ||
275 | static | |
276 | int lttng_uprobes_register(struct lttng_uprobe *uprobe, int fd) | |
3aed4dca FD |
277 | { |
278 | int ret = 0; | |
56377c91 | 279 | struct inode *inode; |
149b9a9d | 280 | |
56377c91 FD |
281 | inode = get_inode_from_fd(fd); |
282 | if (!inode) { | |
5a15f70c | 283 | printk(KERN_WARNING "LTTng: Cannot get inode from fd\n"); |
56377c91 FD |
284 | ret = -EBADF; |
285 | goto inode_error; | |
286 | } | |
83b802dc FD |
287 | uprobe->inode = inode; |
288 | INIT_LIST_HEAD(&uprobe->head); | |
289 | ||
290 | inode_error: | |
291 | return ret; | |
292 | } | |
293 | ||
a67ba386 | 294 | int lttng_uprobes_register_event(const char *name, int fd, struct lttng_kernel_event_recorder *event_recorder) |
83b802dc FD |
295 | { |
296 | int ret = 0; | |
297 | ||
a67ba386 | 298 | ret = lttng_create_uprobe_event(name, event_recorder); |
83b802dc FD |
299 | if (ret) |
300 | goto error; | |
301 | ||
a67ba386 | 302 | ret = lttng_uprobes_register(&event_recorder->priv->parent.u.uprobe, fd); |
83b802dc FD |
303 | if (ret) |
304 | goto register_error; | |
149b9a9d | 305 | |
149b9a9d YB |
306 | return 0; |
307 | ||
83b802dc | 308 | register_error: |
a67ba386 MD |
309 | kfree(event_recorder->priv->parent.desc->event_name); |
310 | kfree(event_recorder->priv->parent.desc); | |
149b9a9d YB |
311 | error: |
312 | return ret; | |
313 | } | |
83b802dc | 314 | EXPORT_SYMBOL_GPL(lttng_uprobes_register_event); |
149b9a9d | 315 | |
9de67196 | 316 | int lttng_uprobes_register_event_notifier(const char *name, int fd, |
a67ba386 | 317 | struct lttng_kernel_event_notifier *event_notifier) |
9de67196 FD |
318 | { |
319 | int ret = 0; | |
320 | ||
321 | ret = lttng_create_uprobe_event_notifier(name, event_notifier); | |
322 | if (ret) | |
323 | goto error; | |
324 | ||
a67ba386 | 325 | ret = lttng_uprobes_register(&event_notifier->priv->parent.u.uprobe, fd); |
9de67196 FD |
326 | if (ret) |
327 | goto register_error; | |
328 | ||
329 | return 0; | |
330 | ||
331 | register_error: | |
a67ba386 MD |
332 | kfree(event_notifier->priv->parent.desc->event_name); |
333 | kfree(event_notifier->priv->parent.desc); | |
9de67196 FD |
334 | error: |
335 | return ret; | |
336 | } | |
337 | EXPORT_SYMBOL_GPL(lttng_uprobes_register_event_notifier); | |
338 | ||
339 | static | |
340 | void lttng_uprobes_unregister(struct inode *inode, struct list_head *head) | |
149b9a9d | 341 | { |
3aed4dca FD |
342 | struct lttng_uprobe_handler *iter, *tmp; |
343 | ||
344 | /* | |
345 | * Iterate over the list of handler, remove each handler from the list | |
346 | * and free the struct. | |
347 | */ | |
9de67196 FD |
348 | list_for_each_entry_safe(iter, tmp, head, node) { |
349 | wrapper_uprobe_unregister(inode, iter->offset, &iter->up_consumer); | |
3aed4dca FD |
350 | list_del(&iter->node); |
351 | kfree(iter); | |
352 | } | |
9de67196 FD |
353 | } |
354 | ||
a67ba386 | 355 | void lttng_uprobes_unregister_event(struct lttng_kernel_event_recorder *event_recorder) |
9de67196 | 356 | { |
a67ba386 | 357 | lttng_uprobes_unregister(event_recorder->priv->parent.u.uprobe.inode, &event_recorder->priv->parent.u.uprobe.head); |
149b9a9d | 358 | } |
83b802dc | 359 | EXPORT_SYMBOL_GPL(lttng_uprobes_unregister_event); |
149b9a9d | 360 | |
a67ba386 | 361 | void lttng_uprobes_unregister_event_notifier(struct lttng_kernel_event_notifier *event_notifier) |
9de67196 | 362 | { |
a67ba386 | 363 | lttng_uprobes_unregister(event_notifier->priv->parent.u.uprobe.inode, &event_notifier->priv->parent.u.uprobe.head); |
9de67196 FD |
364 | } |
365 | EXPORT_SYMBOL_GPL(lttng_uprobes_unregister_event_notifier); | |
366 | ||
a67ba386 | 367 | void lttng_uprobes_destroy_event_private(struct lttng_kernel_event_recorder *event_recorder) |
149b9a9d | 368 | { |
a67ba386 MD |
369 | iput(event_recorder->priv->parent.u.uprobe.inode); |
370 | kfree(event_recorder->priv->parent.desc->fields[0]); | |
371 | kfree(event_recorder->priv->parent.desc->fields); | |
372 | kfree(event_recorder->priv->parent.desc->event_name); | |
373 | kfree(event_recorder->priv->parent.desc); | |
149b9a9d | 374 | } |
83b802dc | 375 | EXPORT_SYMBOL_GPL(lttng_uprobes_destroy_event_private); |
149b9a9d | 376 | |
a67ba386 | 377 | void lttng_uprobes_destroy_event_notifier_private(struct lttng_kernel_event_notifier *event_notifier) |
9de67196 | 378 | { |
a67ba386 MD |
379 | iput(event_notifier->priv->parent.u.uprobe.inode); |
380 | kfree(event_notifier->priv->parent.desc->event_name); | |
381 | kfree(event_notifier->priv->parent.desc); | |
9de67196 FD |
382 | } |
383 | EXPORT_SYMBOL_GPL(lttng_uprobes_destroy_event_notifier_private); | |
384 | ||
149b9a9d YB |
385 | MODULE_LICENSE("GPL and additional rights"); |
386 | MODULE_AUTHOR("Yannick Brosseau"); | |
387 | MODULE_DESCRIPTION("Linux Trace Toolkit Uprobes Support"); |