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; |
a92e844e | 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); | |
f7d06400 | 45 | struct lttng_kernel_channel_buffer *chan = event_recorder->chan; |
e2d5dbc7 | 46 | |
f7d06400 | 47 | if (unlikely(!LTTNG_READ_ONCE(chan->parent.session->active))) |
e2d5dbc7 | 48 | return 0; |
f7d06400 | 49 | if (unlikely(!LTTNG_READ_ONCE(chan->parent.enabled))) |
e2d5dbc7 MD |
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); | |
f7d06400 | 67 | struct lttng_kernel_channel_buffer *chan = event_recorder->chan; |
8a57ec02 | 68 | struct lttng_kernel_ring_buffer_ctx ctx; |
e2d5dbc7 MD |
69 | int ret; |
70 | ||
b1199bd3 MD |
71 | lib_ring_buffer_ctx_init(&ctx, event_recorder, |
72 | sizeof(payload), lttng_alignof(payload), <tng_probe_ctx); | |
e2d5dbc7 | 73 | |
c2fb9c1c | 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 | ||
6c8c025b MD |
102 | static const struct lttng_kernel_event_field *event_fields[] = { |
103 | lttng_kernel_static_event_field("ip", | |
104 | lttng_kernel_static_type_integer_from_type(unsigned long, __BYTE_ORDER, 16), | |
105 | false, false, false), | |
106 | }; | |
107 | ||
108 | static const struct lttng_kernel_tracepoint_class tp_class = { | |
109 | .nr_fields = ARRAY_SIZE(event_fields), | |
110 | .fields = event_fields, | |
111 | }; | |
437d5aa5 | 112 | |
149b9a9d YB |
113 | /* |
114 | * Create event description. | |
115 | */ | |
116 | static | |
a67ba386 | 117 | int lttng_create_uprobe_event(const char *name, struct lttng_kernel_event_recorder *event_recorder) |
149b9a9d | 118 | { |
437d5aa5 | 119 | struct lttng_kernel_event_desc *desc; |
149b9a9d YB |
120 | int ret; |
121 | ||
437d5aa5 | 122 | desc = kzalloc(sizeof(*desc), GFP_KERNEL); |
149b9a9d YB |
123 | if (!desc) |
124 | return -ENOMEM; | |
6c8c025b | 125 | desc->tp_class = &tp_class; |
437d5aa5 MD |
126 | desc->event_name = kstrdup(name, GFP_KERNEL); |
127 | if (!desc->event_name) { | |
149b9a9d YB |
128 | ret = -ENOMEM; |
129 | goto error_str; | |
130 | } | |
149b9a9d | 131 | desc->owner = THIS_MODULE; |
a67ba386 | 132 | event_recorder->priv->parent.desc = desc; |
149b9a9d YB |
133 | |
134 | return 0; | |
135 | ||
149b9a9d YB |
136 | error_str: |
137 | kfree(desc); | |
138 | return ret; | |
139 | } | |
140 | ||
9de67196 FD |
141 | /* |
142 | * Create event_notifier description. | |
143 | */ | |
144 | static | |
a67ba386 | 145 | int lttng_create_uprobe_event_notifier(const char *name, struct lttng_kernel_event_notifier *event_notifier) |
9de67196 | 146 | { |
437d5aa5 | 147 | struct lttng_kernel_event_desc *desc; |
9de67196 FD |
148 | int ret; |
149 | ||
437d5aa5 | 150 | desc = kzalloc(sizeof(*desc), GFP_KERNEL); |
9de67196 FD |
151 | if (!desc) |
152 | return -ENOMEM; | |
6c8c025b | 153 | desc->tp_class = &tp_class; |
437d5aa5 MD |
154 | desc->event_name = kstrdup(name, GFP_KERNEL); |
155 | if (!desc->event_name) { | |
9de67196 FD |
156 | ret = -ENOMEM; |
157 | goto error_str; | |
158 | } | |
9de67196 | 159 | desc->owner = THIS_MODULE; |
a67ba386 | 160 | event_notifier->priv->parent.desc = desc; |
9de67196 FD |
161 | |
162 | return 0; | |
163 | ||
164 | error_str: | |
165 | kfree(desc); | |
166 | return ret; | |
167 | } | |
168 | ||
56377c91 FD |
169 | /* |
170 | * Returns the inode struct from the current task and an fd. The inode is | |
171 | * grabbed by this function and must be put once we are done with it using | |
172 | * iput(). | |
173 | */ | |
174 | static struct inode *get_inode_from_fd(int fd) | |
175 | { | |
176 | struct file *file; | |
177 | struct inode *inode; | |
178 | ||
179 | rcu_read_lock(); | |
180 | /* | |
181 | * Returns the file backing the given fd. Needs to be done inside an RCU | |
182 | * critical section. | |
183 | */ | |
0aebcd68 | 184 | file = lttng_lookup_fd_rcu(fd); |
56377c91 | 185 | if (file == NULL) { |
5a15f70c | 186 | printk(KERN_WARNING "LTTng: Cannot access file backing the fd(%d)\n", fd); |
56377c91 FD |
187 | inode = NULL; |
188 | goto error; | |
189 | } | |
190 | ||
191 | /* Grab a reference on the inode. */ | |
192 | inode = igrab(file->f_path.dentry->d_inode); | |
193 | if (inode == NULL) | |
5a15f70c | 194 | printk(KERN_WARNING "LTTng: Cannot grab a reference on the inode.\n"); |
56377c91 FD |
195 | error: |
196 | rcu_read_unlock(); | |
197 | return inode; | |
198 | } | |
199 | ||
83b802dc FD |
200 | |
201 | static | |
202 | int lttng_uprobes_add_callsite(struct lttng_uprobe *uprobe, | |
606828e4 | 203 | struct lttng_kernel_abi_event_callsite __user *callsite, |
83b802dc FD |
204 | int (*handler)(struct uprobe_consumer *self, struct pt_regs *regs), |
205 | void *priv_data) | |
149b9a9d | 206 | { |
3aed4dca FD |
207 | int ret = 0; |
208 | struct lttng_uprobe_handler *uprobe_handler; | |
209 | ||
83b802dc | 210 | if (!priv_data) { |
3aed4dca FD |
211 | ret = -EINVAL; |
212 | goto end; | |
213 | } | |
214 | ||
215 | uprobe_handler = kzalloc(sizeof(struct lttng_uprobe_handler), GFP_KERNEL); | |
216 | if (!uprobe_handler) { | |
5a15f70c | 217 | printk(KERN_WARNING "LTTng: Error allocating uprobe_handler"); |
3aed4dca FD |
218 | ret = -ENOMEM; |
219 | goto end; | |
220 | } | |
221 | ||
196bfc6a | 222 | /* Ensure the memory we just allocated don't notify page faults. */ |
263b6c88 | 223 | wrapper_vmalloc_sync_mappings(); |
3aed4dca | 224 | |
e2d5dbc7 | 225 | uprobe_handler->event = priv_data; |
83b802dc | 226 | uprobe_handler->up_consumer.handler = handler; |
3aed4dca FD |
227 | |
228 | ret = copy_from_user(&uprobe_handler->offset, &callsite->u.uprobe.offset, sizeof(uint64_t)); | |
229 | if (ret) { | |
230 | goto register_error; | |
231 | } | |
232 | ||
83b802dc | 233 | ret = wrapper_uprobe_register(uprobe->inode, |
3aed4dca FD |
234 | uprobe_handler->offset, &uprobe_handler->up_consumer); |
235 | if (ret) { | |
5a15f70c | 236 | printk(KERN_WARNING "LTTng: Error registering probe on inode %lu " |
83b802dc | 237 | "and offset 0x%llx\n", uprobe->inode->i_ino, |
3aed4dca FD |
238 | uprobe_handler->offset); |
239 | ret = -1; | |
240 | goto register_error; | |
241 | } | |
242 | ||
83b802dc | 243 | list_add(&uprobe_handler->node, &uprobe->head); |
3aed4dca FD |
244 | |
245 | return ret; | |
246 | ||
247 | register_error: | |
248 | kfree(uprobe_handler); | |
249 | end: | |
250 | return ret; | |
251 | } | |
3aed4dca | 252 | |
e2d5dbc7 | 253 | int lttng_uprobes_event_add_callsite(struct lttng_kernel_event_common *event, |
606828e4 | 254 | struct lttng_kernel_abi_event_callsite __user *callsite) |
83b802dc | 255 | { |
e2d5dbc7 MD |
256 | return lttng_uprobes_add_callsite(&event->priv->u.uprobe, callsite, |
257 | lttng_uprobes_event_handler_pre, event); | |
83b802dc FD |
258 | } |
259 | EXPORT_SYMBOL_GPL(lttng_uprobes_event_add_callsite); | |
260 | ||
261 | static | |
262 | int lttng_uprobes_register(struct lttng_uprobe *uprobe, int fd) | |
3aed4dca FD |
263 | { |
264 | int ret = 0; | |
56377c91 | 265 | struct inode *inode; |
149b9a9d | 266 | |
56377c91 FD |
267 | inode = get_inode_from_fd(fd); |
268 | if (!inode) { | |
5a15f70c | 269 | printk(KERN_WARNING "LTTng: Cannot get inode from fd\n"); |
56377c91 FD |
270 | ret = -EBADF; |
271 | goto inode_error; | |
272 | } | |
83b802dc FD |
273 | uprobe->inode = inode; |
274 | INIT_LIST_HEAD(&uprobe->head); | |
275 | ||
276 | inode_error: | |
277 | return ret; | |
278 | } | |
279 | ||
a67ba386 | 280 | int lttng_uprobes_register_event(const char *name, int fd, struct lttng_kernel_event_recorder *event_recorder) |
83b802dc FD |
281 | { |
282 | int ret = 0; | |
283 | ||
a67ba386 | 284 | ret = lttng_create_uprobe_event(name, event_recorder); |
83b802dc FD |
285 | if (ret) |
286 | goto error; | |
287 | ||
a67ba386 | 288 | ret = lttng_uprobes_register(&event_recorder->priv->parent.u.uprobe, fd); |
83b802dc FD |
289 | if (ret) |
290 | goto register_error; | |
149b9a9d | 291 | |
149b9a9d YB |
292 | return 0; |
293 | ||
83b802dc | 294 | register_error: |
a67ba386 MD |
295 | kfree(event_recorder->priv->parent.desc->event_name); |
296 | kfree(event_recorder->priv->parent.desc); | |
149b9a9d YB |
297 | error: |
298 | return ret; | |
299 | } | |
83b802dc | 300 | EXPORT_SYMBOL_GPL(lttng_uprobes_register_event); |
149b9a9d | 301 | |
9de67196 | 302 | int lttng_uprobes_register_event_notifier(const char *name, int fd, |
a67ba386 | 303 | struct lttng_kernel_event_notifier *event_notifier) |
9de67196 FD |
304 | { |
305 | int ret = 0; | |
306 | ||
307 | ret = lttng_create_uprobe_event_notifier(name, event_notifier); | |
308 | if (ret) | |
309 | goto error; | |
310 | ||
a67ba386 | 311 | ret = lttng_uprobes_register(&event_notifier->priv->parent.u.uprobe, fd); |
9de67196 FD |
312 | if (ret) |
313 | goto register_error; | |
314 | ||
315 | return 0; | |
316 | ||
317 | register_error: | |
a67ba386 MD |
318 | kfree(event_notifier->priv->parent.desc->event_name); |
319 | kfree(event_notifier->priv->parent.desc); | |
9de67196 FD |
320 | error: |
321 | return ret; | |
322 | } | |
323 | EXPORT_SYMBOL_GPL(lttng_uprobes_register_event_notifier); | |
324 | ||
325 | static | |
326 | void lttng_uprobes_unregister(struct inode *inode, struct list_head *head) | |
149b9a9d | 327 | { |
3aed4dca FD |
328 | struct lttng_uprobe_handler *iter, *tmp; |
329 | ||
330 | /* | |
331 | * Iterate over the list of handler, remove each handler from the list | |
332 | * and free the struct. | |
333 | */ | |
9de67196 FD |
334 | list_for_each_entry_safe(iter, tmp, head, node) { |
335 | wrapper_uprobe_unregister(inode, iter->offset, &iter->up_consumer); | |
3aed4dca FD |
336 | list_del(&iter->node); |
337 | kfree(iter); | |
338 | } | |
9de67196 FD |
339 | } |
340 | ||
a67ba386 | 341 | void lttng_uprobes_unregister_event(struct lttng_kernel_event_recorder *event_recorder) |
9de67196 | 342 | { |
a67ba386 | 343 | lttng_uprobes_unregister(event_recorder->priv->parent.u.uprobe.inode, &event_recorder->priv->parent.u.uprobe.head); |
149b9a9d | 344 | } |
83b802dc | 345 | EXPORT_SYMBOL_GPL(lttng_uprobes_unregister_event); |
149b9a9d | 346 | |
a67ba386 | 347 | void lttng_uprobes_unregister_event_notifier(struct lttng_kernel_event_notifier *event_notifier) |
9de67196 | 348 | { |
a67ba386 | 349 | lttng_uprobes_unregister(event_notifier->priv->parent.u.uprobe.inode, &event_notifier->priv->parent.u.uprobe.head); |
9de67196 FD |
350 | } |
351 | EXPORT_SYMBOL_GPL(lttng_uprobes_unregister_event_notifier); | |
352 | ||
a67ba386 | 353 | void lttng_uprobes_destroy_event_private(struct lttng_kernel_event_recorder *event_recorder) |
149b9a9d | 354 | { |
a67ba386 | 355 | iput(event_recorder->priv->parent.u.uprobe.inode); |
a67ba386 MD |
356 | kfree(event_recorder->priv->parent.desc->event_name); |
357 | kfree(event_recorder->priv->parent.desc); | |
149b9a9d | 358 | } |
83b802dc | 359 | EXPORT_SYMBOL_GPL(lttng_uprobes_destroy_event_private); |
149b9a9d | 360 | |
a67ba386 | 361 | void lttng_uprobes_destroy_event_notifier_private(struct lttng_kernel_event_notifier *event_notifier) |
9de67196 | 362 | { |
a67ba386 MD |
363 | iput(event_notifier->priv->parent.u.uprobe.inode); |
364 | kfree(event_notifier->priv->parent.desc->event_name); | |
365 | kfree(event_notifier->priv->parent.desc); | |
9de67196 FD |
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"); |