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); | |
a67ba386 | 31 | struct lttng_kernel_event_recorder *event_recorder = uprobe_handler->u.event; |
149b9a9d | 32 | struct lttng_probe_ctx lttng_probe_ctx = { |
a67ba386 | 33 | .event = event_recorder, |
149b9a9d YB |
34 | .interruptible = !lttng_regs_irqs_disabled(regs), |
35 | }; | |
a67ba386 | 36 | struct lttng_channel *chan = event_recorder->chan; |
149b9a9d YB |
37 | struct lib_ring_buffer_ctx ctx; |
38 | int ret; | |
39 | ||
40 | struct { | |
41 | unsigned long ip; | |
56377c91 | 42 | } payload; |
149b9a9d | 43 | |
585e5dcc | 44 | if (unlikely(!LTTNG_READ_ONCE(chan->session->active))) |
149b9a9d | 45 | return 0; |
585e5dcc | 46 | if (unlikely(!LTTNG_READ_ONCE(chan->enabled))) |
149b9a9d | 47 | return 0; |
a67ba386 | 48 | if (unlikely(!LTTNG_READ_ONCE(event_recorder->parent.enabled))) |
149b9a9d YB |
49 | return 0; |
50 | ||
51 | lib_ring_buffer_ctx_init(&ctx, chan->chan, <tng_probe_ctx, | |
52 | sizeof(payload), lttng_alignof(payload), -1); | |
53 | ||
a67ba386 | 54 | ret = chan->ops->event_reserve(&ctx, event_recorder->priv->id); |
149b9a9d YB |
55 | if (ret < 0) |
56 | return 0; | |
57 | ||
58 | /* Event payload. */ | |
7445d54f | 59 | payload.ip = (unsigned long)instruction_pointer(regs); |
56377c91 | 60 | |
149b9a9d YB |
61 | lib_ring_buffer_align_ctx(&ctx, lttng_alignof(payload)); |
62 | chan->ops->event_write(&ctx, &payload, sizeof(payload)); | |
63 | chan->ops->event_commit(&ctx); | |
64 | return 0; | |
65 | } | |
66 | ||
9de67196 FD |
67 | static |
68 | int lttng_uprobes_event_notifier_handler_pre(struct uprobe_consumer *uc, struct pt_regs *regs) | |
69 | { | |
70 | struct lttng_uprobe_handler *uprobe_handler = | |
71 | container_of(uc, struct lttng_uprobe_handler, up_consumer); | |
a67ba386 MD |
72 | struct lttng_kernel_event_notifier *event_notifier = uprobe_handler->u.event_notifier; |
73 | struct lttng_kernel_notification_ctx notif_ctx; | |
9de67196 | 74 | |
a67ba386 | 75 | if (unlikely(!READ_ONCE(event_notifier->parent.enabled))) |
9de67196 FD |
76 | return 0; |
77 | ||
c3eddb2e | 78 | notif_ctx.eval_capture = LTTNG_READ_ONCE(event_notifier->eval_capture); |
a67ba386 | 79 | event_notifier->notification_send(event_notifier, NULL, NULL, ¬if_ctx); |
9de67196 FD |
80 | return 0; |
81 | } | |
82 | ||
437d5aa5 MD |
83 | static const struct lttng_kernel_type_common *event_type = |
84 | lttng_kernel_static_type_integer_from_type(unsigned long, __BYTE_ORDER, 16); | |
85 | ||
149b9a9d YB |
86 | /* |
87 | * Create event description. | |
88 | */ | |
89 | static | |
a67ba386 | 90 | int lttng_create_uprobe_event(const char *name, struct lttng_kernel_event_recorder *event_recorder) |
149b9a9d | 91 | { |
437d5aa5 MD |
92 | const struct lttng_kernel_event_field **fieldp_array; |
93 | struct lttng_kernel_event_field *field; | |
94 | struct lttng_kernel_event_desc *desc; | |
149b9a9d YB |
95 | int ret; |
96 | ||
437d5aa5 | 97 | desc = kzalloc(sizeof(*desc), GFP_KERNEL); |
149b9a9d YB |
98 | if (!desc) |
99 | return -ENOMEM; | |
437d5aa5 MD |
100 | desc->event_name = kstrdup(name, GFP_KERNEL); |
101 | if (!desc->event_name) { | |
149b9a9d YB |
102 | ret = -ENOMEM; |
103 | goto error_str; | |
104 | } | |
149b9a9d | 105 | desc->nr_fields = 1; |
437d5aa5 MD |
106 | fieldp_array = kzalloc(1 * sizeof(struct lttng_kernel_event_field *), GFP_KERNEL); |
107 | if (!fieldp_array) { | |
149b9a9d | 108 | ret = -ENOMEM; |
437d5aa5 | 109 | goto error_fieldp_array; |
149b9a9d | 110 | } |
437d5aa5 MD |
111 | desc->fields = fieldp_array; |
112 | desc->fields[0] = field = | |
113 | kzalloc(sizeof(struct lttng_kernel_event_field), GFP_KERNEL); | |
114 | if (!field) { | |
115 | ret = -ENOMEM; | |
116 | goto error_field; | |
117 | } | |
118 | field->name = "ip"; | |
119 | field->type = event_type; | |
149b9a9d | 120 | desc->owner = THIS_MODULE; |
a67ba386 | 121 | event_recorder->priv->parent.desc = desc; |
149b9a9d YB |
122 | |
123 | return 0; | |
124 | ||
437d5aa5 MD |
125 | error_field: |
126 | kfree(fieldp_array); | |
127 | error_fieldp_array: | |
128 | kfree(desc->event_name); | |
149b9a9d YB |
129 | error_str: |
130 | kfree(desc); | |
131 | return ret; | |
132 | } | |
133 | ||
9de67196 FD |
134 | /* |
135 | * Create event_notifier description. | |
136 | */ | |
137 | static | |
a67ba386 | 138 | int lttng_create_uprobe_event_notifier(const char *name, struct lttng_kernel_event_notifier *event_notifier) |
9de67196 | 139 | { |
437d5aa5 | 140 | struct lttng_kernel_event_desc *desc; |
9de67196 FD |
141 | int ret; |
142 | ||
437d5aa5 | 143 | desc = kzalloc(sizeof(*desc), GFP_KERNEL); |
9de67196 FD |
144 | if (!desc) |
145 | return -ENOMEM; | |
437d5aa5 MD |
146 | desc->event_name = kstrdup(name, GFP_KERNEL); |
147 | if (!desc->event_name) { | |
9de67196 FD |
148 | ret = -ENOMEM; |
149 | goto error_str; | |
150 | } | |
151 | ||
152 | desc->nr_fields = 0; | |
153 | ||
154 | desc->owner = THIS_MODULE; | |
a67ba386 | 155 | event_notifier->priv->parent.desc = desc; |
9de67196 FD |
156 | |
157 | return 0; | |
158 | ||
159 | error_str: | |
160 | kfree(desc); | |
161 | return ret; | |
162 | } | |
163 | ||
56377c91 FD |
164 | /* |
165 | * Returns the inode struct from the current task and an fd. The inode is | |
166 | * grabbed by this function and must be put once we are done with it using | |
167 | * iput(). | |
168 | */ | |
169 | static struct inode *get_inode_from_fd(int fd) | |
170 | { | |
171 | struct file *file; | |
172 | struct inode *inode; | |
173 | ||
174 | rcu_read_lock(); | |
175 | /* | |
176 | * Returns the file backing the given fd. Needs to be done inside an RCU | |
177 | * critical section. | |
178 | */ | |
0aebcd68 | 179 | file = lttng_lookup_fd_rcu(fd); |
56377c91 | 180 | if (file == NULL) { |
5a15f70c | 181 | printk(KERN_WARNING "LTTng: Cannot access file backing the fd(%d)\n", fd); |
56377c91 FD |
182 | inode = NULL; |
183 | goto error; | |
184 | } | |
185 | ||
186 | /* Grab a reference on the inode. */ | |
187 | inode = igrab(file->f_path.dentry->d_inode); | |
188 | if (inode == NULL) | |
5a15f70c | 189 | printk(KERN_WARNING "LTTng: Cannot grab a reference on the inode.\n"); |
56377c91 FD |
190 | error: |
191 | rcu_read_unlock(); | |
192 | return inode; | |
193 | } | |
194 | ||
83b802dc FD |
195 | |
196 | static | |
197 | int lttng_uprobes_add_callsite(struct lttng_uprobe *uprobe, | |
606828e4 | 198 | struct lttng_kernel_abi_event_callsite __user *callsite, |
83b802dc FD |
199 | int (*handler)(struct uprobe_consumer *self, struct pt_regs *regs), |
200 | void *priv_data) | |
149b9a9d | 201 | { |
3aed4dca FD |
202 | int ret = 0; |
203 | struct lttng_uprobe_handler *uprobe_handler; | |
204 | ||
83b802dc | 205 | if (!priv_data) { |
3aed4dca FD |
206 | ret = -EINVAL; |
207 | goto end; | |
208 | } | |
209 | ||
210 | uprobe_handler = kzalloc(sizeof(struct lttng_uprobe_handler), GFP_KERNEL); | |
211 | if (!uprobe_handler) { | |
5a15f70c | 212 | printk(KERN_WARNING "LTTng: Error allocating uprobe_handler"); |
3aed4dca FD |
213 | ret = -ENOMEM; |
214 | goto end; | |
215 | } | |
216 | ||
196bfc6a | 217 | /* Ensure the memory we just allocated don't notify page faults. */ |
263b6c88 | 218 | wrapper_vmalloc_sync_mappings(); |
3aed4dca | 219 | |
83b802dc FD |
220 | uprobe_handler->u.event = priv_data; |
221 | uprobe_handler->up_consumer.handler = handler; | |
3aed4dca FD |
222 | |
223 | ret = copy_from_user(&uprobe_handler->offset, &callsite->u.uprobe.offset, sizeof(uint64_t)); | |
224 | if (ret) { | |
225 | goto register_error; | |
226 | } | |
227 | ||
83b802dc | 228 | ret = wrapper_uprobe_register(uprobe->inode, |
3aed4dca FD |
229 | uprobe_handler->offset, &uprobe_handler->up_consumer); |
230 | if (ret) { | |
5a15f70c | 231 | printk(KERN_WARNING "LTTng: Error registering probe on inode %lu " |
83b802dc | 232 | "and offset 0x%llx\n", uprobe->inode->i_ino, |
3aed4dca FD |
233 | uprobe_handler->offset); |
234 | ret = -1; | |
235 | goto register_error; | |
236 | } | |
237 | ||
83b802dc | 238 | list_add(&uprobe_handler->node, &uprobe->head); |
3aed4dca FD |
239 | |
240 | return ret; | |
241 | ||
242 | register_error: | |
243 | kfree(uprobe_handler); | |
244 | end: | |
245 | return ret; | |
246 | } | |
3aed4dca | 247 | |
a67ba386 | 248 | int lttng_uprobes_event_add_callsite(struct lttng_kernel_event_recorder *event_recorder, |
606828e4 | 249 | struct lttng_kernel_abi_event_callsite __user *callsite) |
83b802dc | 250 | { |
a67ba386 MD |
251 | return lttng_uprobes_add_callsite(&event_recorder->priv->parent.u.uprobe, callsite, |
252 | lttng_uprobes_event_handler_pre, event_recorder); | |
83b802dc FD |
253 | } |
254 | EXPORT_SYMBOL_GPL(lttng_uprobes_event_add_callsite); | |
255 | ||
a67ba386 | 256 | int lttng_uprobes_event_notifier_add_callsite(struct lttng_kernel_event_notifier *event_notifier, |
606828e4 | 257 | struct lttng_kernel_abi_event_callsite __user *callsite) |
9de67196 | 258 | { |
a67ba386 | 259 | return lttng_uprobes_add_callsite(&event_notifier->priv->parent.u.uprobe, callsite, |
9de67196 FD |
260 | lttng_uprobes_event_notifier_handler_pre, event_notifier); |
261 | } | |
262 | EXPORT_SYMBOL_GPL(lttng_uprobes_event_notifier_add_callsite); | |
263 | ||
83b802dc FD |
264 | static |
265 | int lttng_uprobes_register(struct lttng_uprobe *uprobe, int fd) | |
3aed4dca FD |
266 | { |
267 | int ret = 0; | |
56377c91 | 268 | struct inode *inode; |
149b9a9d | 269 | |
56377c91 FD |
270 | inode = get_inode_from_fd(fd); |
271 | if (!inode) { | |
5a15f70c | 272 | printk(KERN_WARNING "LTTng: Cannot get inode from fd\n"); |
56377c91 FD |
273 | ret = -EBADF; |
274 | goto inode_error; | |
275 | } | |
83b802dc FD |
276 | uprobe->inode = inode; |
277 | INIT_LIST_HEAD(&uprobe->head); | |
278 | ||
279 | inode_error: | |
280 | return ret; | |
281 | } | |
282 | ||
a67ba386 | 283 | int lttng_uprobes_register_event(const char *name, int fd, struct lttng_kernel_event_recorder *event_recorder) |
83b802dc FD |
284 | { |
285 | int ret = 0; | |
286 | ||
a67ba386 | 287 | ret = lttng_create_uprobe_event(name, event_recorder); |
83b802dc FD |
288 | if (ret) |
289 | goto error; | |
290 | ||
a67ba386 | 291 | ret = lttng_uprobes_register(&event_recorder->priv->parent.u.uprobe, fd); |
83b802dc FD |
292 | if (ret) |
293 | goto register_error; | |
149b9a9d | 294 | |
149b9a9d YB |
295 | return 0; |
296 | ||
83b802dc | 297 | register_error: |
a67ba386 MD |
298 | kfree(event_recorder->priv->parent.desc->event_name); |
299 | kfree(event_recorder->priv->parent.desc); | |
149b9a9d YB |
300 | error: |
301 | return ret; | |
302 | } | |
83b802dc | 303 | EXPORT_SYMBOL_GPL(lttng_uprobes_register_event); |
149b9a9d | 304 | |
9de67196 | 305 | int lttng_uprobes_register_event_notifier(const char *name, int fd, |
a67ba386 | 306 | struct lttng_kernel_event_notifier *event_notifier) |
9de67196 FD |
307 | { |
308 | int ret = 0; | |
309 | ||
310 | ret = lttng_create_uprobe_event_notifier(name, event_notifier); | |
311 | if (ret) | |
312 | goto error; | |
313 | ||
a67ba386 | 314 | ret = lttng_uprobes_register(&event_notifier->priv->parent.u.uprobe, fd); |
9de67196 FD |
315 | if (ret) |
316 | goto register_error; | |
317 | ||
318 | return 0; | |
319 | ||
320 | register_error: | |
a67ba386 MD |
321 | kfree(event_notifier->priv->parent.desc->event_name); |
322 | kfree(event_notifier->priv->parent.desc); | |
9de67196 FD |
323 | error: |
324 | return ret; | |
325 | } | |
326 | EXPORT_SYMBOL_GPL(lttng_uprobes_register_event_notifier); | |
327 | ||
328 | static | |
329 | void lttng_uprobes_unregister(struct inode *inode, struct list_head *head) | |
149b9a9d | 330 | { |
3aed4dca FD |
331 | struct lttng_uprobe_handler *iter, *tmp; |
332 | ||
333 | /* | |
334 | * Iterate over the list of handler, remove each handler from the list | |
335 | * and free the struct. | |
336 | */ | |
9de67196 FD |
337 | list_for_each_entry_safe(iter, tmp, head, node) { |
338 | wrapper_uprobe_unregister(inode, iter->offset, &iter->up_consumer); | |
3aed4dca FD |
339 | list_del(&iter->node); |
340 | kfree(iter); | |
341 | } | |
9de67196 FD |
342 | |
343 | } | |
344 | ||
a67ba386 | 345 | void lttng_uprobes_unregister_event(struct lttng_kernel_event_recorder *event_recorder) |
9de67196 | 346 | { |
a67ba386 | 347 | lttng_uprobes_unregister(event_recorder->priv->parent.u.uprobe.inode, &event_recorder->priv->parent.u.uprobe.head); |
149b9a9d | 348 | } |
83b802dc | 349 | EXPORT_SYMBOL_GPL(lttng_uprobes_unregister_event); |
149b9a9d | 350 | |
a67ba386 | 351 | void lttng_uprobes_unregister_event_notifier(struct lttng_kernel_event_notifier *event_notifier) |
9de67196 | 352 | { |
a67ba386 | 353 | lttng_uprobes_unregister(event_notifier->priv->parent.u.uprobe.inode, &event_notifier->priv->parent.u.uprobe.head); |
9de67196 FD |
354 | } |
355 | EXPORT_SYMBOL_GPL(lttng_uprobes_unregister_event_notifier); | |
356 | ||
a67ba386 | 357 | void lttng_uprobes_destroy_event_private(struct lttng_kernel_event_recorder *event_recorder) |
149b9a9d | 358 | { |
a67ba386 MD |
359 | iput(event_recorder->priv->parent.u.uprobe.inode); |
360 | kfree(event_recorder->priv->parent.desc->fields[0]); | |
361 | kfree(event_recorder->priv->parent.desc->fields); | |
362 | kfree(event_recorder->priv->parent.desc->event_name); | |
363 | kfree(event_recorder->priv->parent.desc); | |
149b9a9d | 364 | } |
83b802dc | 365 | EXPORT_SYMBOL_GPL(lttng_uprobes_destroy_event_private); |
149b9a9d | 366 | |
a67ba386 | 367 | void lttng_uprobes_destroy_event_notifier_private(struct lttng_kernel_event_notifier *event_notifier) |
9de67196 | 368 | { |
a67ba386 MD |
369 | iput(event_notifier->priv->parent.u.uprobe.inode); |
370 | kfree(event_notifier->priv->parent.desc->event_name); | |
371 | kfree(event_notifier->priv->parent.desc); | |
9de67196 FD |
372 | } |
373 | EXPORT_SYMBOL_GPL(lttng_uprobes_destroy_event_notifier_private); | |
374 | ||
149b9a9d YB |
375 | MODULE_LICENSE("GPL and additional rights"); |
376 | MODULE_AUTHOR("Yannick Brosseau"); | |
377 | MODULE_DESCRIPTION("Linux Trace Toolkit Uprobes Support"); |