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); | |
ac847066 | 45 | struct lttng_kernel_channel_buffer *chan = event_recorder->chan; |
e2d5dbc7 | 46 | |
ac847066 | 47 | if (unlikely(!LTTNG_READ_ONCE(chan->parent.session->active))) |
e2d5dbc7 | 48 | return 0; |
ac847066 | 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); | |
ac847066 | 67 | struct lttng_kernel_channel_buffer *chan = event_recorder->chan; |
e27e4381 | 68 | struct lttng_kernel_ring_buffer_ctx ctx; |
e2d5dbc7 MD |
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 | ||
77fcffef | 81 | chan->ops->event_write(&ctx, &payload, sizeof(payload), lttng_alignof(payload)); |
e2d5dbc7 MD |
82 | chan->ops->event_commit(&ctx); |
83 | break; | |
84 | } | |
85 | case LTTNG_KERNEL_EVENT_TYPE_NOTIFIER: | |
86 | { | |
87 | struct lttng_kernel_event_notifier *event_notifier = | |
88 | container_of(event, struct lttng_kernel_event_notifier, parent); | |
89 | struct lttng_kernel_notification_ctx notif_ctx; | |
90 | ||
91 | notif_ctx.eval_capture = LTTNG_READ_ONCE(event_notifier->eval_capture); | |
92 | event_notifier->notification_send(event_notifier, NULL, NULL, ¬if_ctx); | |
93 | break; | |
94 | } | |
95 | default: | |
96 | WARN_ON_ONCE(1); | |
97 | } | |
9de67196 FD |
98 | return 0; |
99 | } | |
100 | ||
e69abdfd MD |
101 | static const struct lttng_kernel_event_field *event_fields[] = { |
102 | lttng_kernel_static_event_field("ip", | |
103 | lttng_kernel_static_type_integer_from_type(unsigned long, __BYTE_ORDER, 16), | |
104 | false, false, false), | |
105 | }; | |
106 | ||
107 | static const struct lttng_kernel_tracepoint_class tp_class = { | |
108 | .nr_fields = ARRAY_SIZE(event_fields), | |
109 | .fields = event_fields, | |
110 | }; | |
437d5aa5 | 111 | |
149b9a9d YB |
112 | /* |
113 | * Create event description. | |
114 | */ | |
115 | static | |
a67ba386 | 116 | int lttng_create_uprobe_event(const char *name, struct lttng_kernel_event_recorder *event_recorder) |
149b9a9d | 117 | { |
437d5aa5 | 118 | struct lttng_kernel_event_desc *desc; |
149b9a9d YB |
119 | int ret; |
120 | ||
437d5aa5 | 121 | desc = kzalloc(sizeof(*desc), GFP_KERNEL); |
149b9a9d YB |
122 | if (!desc) |
123 | return -ENOMEM; | |
e69abdfd | 124 | desc->tp_class = &tp_class; |
437d5aa5 MD |
125 | desc->event_name = kstrdup(name, GFP_KERNEL); |
126 | if (!desc->event_name) { | |
149b9a9d YB |
127 | ret = -ENOMEM; |
128 | goto error_str; | |
129 | } | |
149b9a9d | 130 | desc->owner = THIS_MODULE; |
a67ba386 | 131 | event_recorder->priv->parent.desc = desc; |
149b9a9d YB |
132 | |
133 | return 0; | |
134 | ||
149b9a9d YB |
135 | error_str: |
136 | kfree(desc); | |
137 | return ret; | |
138 | } | |
139 | ||
9de67196 FD |
140 | /* |
141 | * Create event_notifier description. | |
142 | */ | |
143 | static | |
a67ba386 | 144 | int lttng_create_uprobe_event_notifier(const char *name, struct lttng_kernel_event_notifier *event_notifier) |
9de67196 | 145 | { |
437d5aa5 | 146 | struct lttng_kernel_event_desc *desc; |
9de67196 FD |
147 | int ret; |
148 | ||
437d5aa5 | 149 | desc = kzalloc(sizeof(*desc), GFP_KERNEL); |
9de67196 FD |
150 | if (!desc) |
151 | return -ENOMEM; | |
e69abdfd | 152 | desc->tp_class = &tp_class; |
437d5aa5 MD |
153 | desc->event_name = kstrdup(name, GFP_KERNEL); |
154 | if (!desc->event_name) { | |
9de67196 FD |
155 | ret = -ENOMEM; |
156 | goto error_str; | |
157 | } | |
9de67196 | 158 | desc->owner = THIS_MODULE; |
a67ba386 | 159 | event_notifier->priv->parent.desc = desc; |
9de67196 FD |
160 | |
161 | return 0; | |
162 | ||
163 | error_str: | |
164 | kfree(desc); | |
165 | return ret; | |
166 | } | |
167 | ||
56377c91 FD |
168 | /* |
169 | * Returns the inode struct from the current task and an fd. The inode is | |
170 | * grabbed by this function and must be put once we are done with it using | |
171 | * iput(). | |
172 | */ | |
173 | static struct inode *get_inode_from_fd(int fd) | |
174 | { | |
175 | struct file *file; | |
176 | struct inode *inode; | |
177 | ||
178 | rcu_read_lock(); | |
179 | /* | |
180 | * Returns the file backing the given fd. Needs to be done inside an RCU | |
181 | * critical section. | |
182 | */ | |
0aebcd68 | 183 | file = lttng_lookup_fd_rcu(fd); |
56377c91 | 184 | if (file == NULL) { |
5a15f70c | 185 | printk(KERN_WARNING "LTTng: Cannot access file backing the fd(%d)\n", fd); |
56377c91 FD |
186 | inode = NULL; |
187 | goto error; | |
188 | } | |
189 | ||
190 | /* Grab a reference on the inode. */ | |
191 | inode = igrab(file->f_path.dentry->d_inode); | |
192 | if (inode == NULL) | |
5a15f70c | 193 | printk(KERN_WARNING "LTTng: Cannot grab a reference on the inode.\n"); |
56377c91 FD |
194 | error: |
195 | rcu_read_unlock(); | |
196 | return inode; | |
197 | } | |
198 | ||
83b802dc FD |
199 | |
200 | static | |
201 | int lttng_uprobes_add_callsite(struct lttng_uprobe *uprobe, | |
606828e4 | 202 | struct lttng_kernel_abi_event_callsite __user *callsite, |
83b802dc FD |
203 | int (*handler)(struct uprobe_consumer *self, struct pt_regs *regs), |
204 | void *priv_data) | |
149b9a9d | 205 | { |
3aed4dca FD |
206 | int ret = 0; |
207 | struct lttng_uprobe_handler *uprobe_handler; | |
208 | ||
83b802dc | 209 | if (!priv_data) { |
3aed4dca FD |
210 | ret = -EINVAL; |
211 | goto end; | |
212 | } | |
213 | ||
214 | uprobe_handler = kzalloc(sizeof(struct lttng_uprobe_handler), GFP_KERNEL); | |
215 | if (!uprobe_handler) { | |
5a15f70c | 216 | printk(KERN_WARNING "LTTng: Error allocating uprobe_handler"); |
3aed4dca FD |
217 | ret = -ENOMEM; |
218 | goto end; | |
219 | } | |
220 | ||
196bfc6a | 221 | /* Ensure the memory we just allocated don't notify page faults. */ |
263b6c88 | 222 | wrapper_vmalloc_sync_mappings(); |
3aed4dca | 223 | |
e2d5dbc7 | 224 | uprobe_handler->event = priv_data; |
83b802dc | 225 | uprobe_handler->up_consumer.handler = handler; |
3aed4dca FD |
226 | |
227 | ret = copy_from_user(&uprobe_handler->offset, &callsite->u.uprobe.offset, sizeof(uint64_t)); | |
228 | if (ret) { | |
229 | goto register_error; | |
230 | } | |
231 | ||
83b802dc | 232 | ret = wrapper_uprobe_register(uprobe->inode, |
3aed4dca FD |
233 | uprobe_handler->offset, &uprobe_handler->up_consumer); |
234 | if (ret) { | |
5a15f70c | 235 | printk(KERN_WARNING "LTTng: Error registering probe on inode %lu " |
83b802dc | 236 | "and offset 0x%llx\n", uprobe->inode->i_ino, |
3aed4dca FD |
237 | uprobe_handler->offset); |
238 | ret = -1; | |
239 | goto register_error; | |
240 | } | |
241 | ||
83b802dc | 242 | list_add(&uprobe_handler->node, &uprobe->head); |
3aed4dca FD |
243 | |
244 | return ret; | |
245 | ||
246 | register_error: | |
247 | kfree(uprobe_handler); | |
248 | end: | |
249 | return ret; | |
250 | } | |
3aed4dca | 251 | |
e2d5dbc7 | 252 | int lttng_uprobes_event_add_callsite(struct lttng_kernel_event_common *event, |
606828e4 | 253 | struct lttng_kernel_abi_event_callsite __user *callsite) |
83b802dc | 254 | { |
e2d5dbc7 MD |
255 | return lttng_uprobes_add_callsite(&event->priv->u.uprobe, callsite, |
256 | lttng_uprobes_event_handler_pre, event); | |
83b802dc FD |
257 | } |
258 | EXPORT_SYMBOL_GPL(lttng_uprobes_event_add_callsite); | |
259 | ||
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 | ||
a67ba386 | 279 | int lttng_uprobes_register_event(const char *name, int fd, struct lttng_kernel_event_recorder *event_recorder) |
83b802dc FD |
280 | { |
281 | int ret = 0; | |
282 | ||
a67ba386 | 283 | ret = lttng_create_uprobe_event(name, event_recorder); |
83b802dc FD |
284 | if (ret) |
285 | goto error; | |
286 | ||
a67ba386 | 287 | ret = lttng_uprobes_register(&event_recorder->priv->parent.u.uprobe, fd); |
83b802dc FD |
288 | if (ret) |
289 | goto register_error; | |
149b9a9d | 290 | |
149b9a9d YB |
291 | return 0; |
292 | ||
83b802dc | 293 | register_error: |
a67ba386 MD |
294 | kfree(event_recorder->priv->parent.desc->event_name); |
295 | kfree(event_recorder->priv->parent.desc); | |
149b9a9d YB |
296 | error: |
297 | return ret; | |
298 | } | |
83b802dc | 299 | EXPORT_SYMBOL_GPL(lttng_uprobes_register_event); |
149b9a9d | 300 | |
9de67196 | 301 | int lttng_uprobes_register_event_notifier(const char *name, int fd, |
a67ba386 | 302 | struct lttng_kernel_event_notifier *event_notifier) |
9de67196 FD |
303 | { |
304 | int ret = 0; | |
305 | ||
306 | ret = lttng_create_uprobe_event_notifier(name, event_notifier); | |
307 | if (ret) | |
308 | goto error; | |
309 | ||
a67ba386 | 310 | ret = lttng_uprobes_register(&event_notifier->priv->parent.u.uprobe, fd); |
9de67196 FD |
311 | if (ret) |
312 | goto register_error; | |
313 | ||
314 | return 0; | |
315 | ||
316 | register_error: | |
a67ba386 MD |
317 | kfree(event_notifier->priv->parent.desc->event_name); |
318 | kfree(event_notifier->priv->parent.desc); | |
9de67196 FD |
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 | ||
a67ba386 | 340 | void lttng_uprobes_unregister_event(struct lttng_kernel_event_recorder *event_recorder) |
9de67196 | 341 | { |
a67ba386 | 342 | lttng_uprobes_unregister(event_recorder->priv->parent.u.uprobe.inode, &event_recorder->priv->parent.u.uprobe.head); |
149b9a9d | 343 | } |
83b802dc | 344 | EXPORT_SYMBOL_GPL(lttng_uprobes_unregister_event); |
149b9a9d | 345 | |
a67ba386 | 346 | void lttng_uprobes_unregister_event_notifier(struct lttng_kernel_event_notifier *event_notifier) |
9de67196 | 347 | { |
a67ba386 | 348 | lttng_uprobes_unregister(event_notifier->priv->parent.u.uprobe.inode, &event_notifier->priv->parent.u.uprobe.head); |
9de67196 FD |
349 | } |
350 | EXPORT_SYMBOL_GPL(lttng_uprobes_unregister_event_notifier); | |
351 | ||
a67ba386 | 352 | void lttng_uprobes_destroy_event_private(struct lttng_kernel_event_recorder *event_recorder) |
149b9a9d | 353 | { |
a67ba386 | 354 | iput(event_recorder->priv->parent.u.uprobe.inode); |
a67ba386 MD |
355 | kfree(event_recorder->priv->parent.desc->event_name); |
356 | kfree(event_recorder->priv->parent.desc); | |
149b9a9d | 357 | } |
83b802dc | 358 | EXPORT_SYMBOL_GPL(lttng_uprobes_destroy_event_private); |
149b9a9d | 359 | |
a67ba386 | 360 | void lttng_uprobes_destroy_event_notifier_private(struct lttng_kernel_event_notifier *event_notifier) |
9de67196 | 361 | { |
a67ba386 MD |
362 | iput(event_notifier->priv->parent.u.uprobe.inode); |
363 | kfree(event_notifier->priv->parent.desc->event_name); | |
364 | kfree(event_notifier->priv->parent.desc); | |
9de67196 FD |
365 | } |
366 | EXPORT_SYMBOL_GPL(lttng_uprobes_destroy_event_notifier_private); | |
367 | ||
149b9a9d YB |
368 | MODULE_LICENSE("GPL and additional rights"); |
369 | MODULE_AUTHOR("Yannick Brosseau"); | |
370 | MODULE_DESCRIPTION("Linux Trace Toolkit Uprobes Support"); |