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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> |
853f5b15 MJ |
18 | #include <linux/uprobes.h> |
19 | ||
2df37e95 | 20 | #include <lttng/events.h> |
a67ba386 | 21 | #include <lttng/events-internal.h> |
2df37e95 | 22 | #include <lttng/tracer.h> |
149b9a9d | 23 | #include <wrapper/irqflags.h> |
24591303 | 24 | #include <ringbuffer/frontend_types.h> |
149b9a9d YB |
25 | #include <wrapper/vmalloc.h> |
26 | ||
27 | static | |
83b802dc | 28 | int lttng_uprobes_event_handler_pre(struct uprobe_consumer *uc, struct pt_regs *regs) |
149b9a9d | 29 | { |
3aed4dca FD |
30 | struct lttng_uprobe_handler *uprobe_handler = |
31 | container_of(uc, struct lttng_uprobe_handler, up_consumer); | |
e2d5dbc7 | 32 | struct lttng_kernel_event_common *event = uprobe_handler->event; |
a92e844e | 33 | struct lttng_kernel_probe_ctx lttng_probe_ctx = { |
e2d5dbc7 | 34 | .event = event, |
149b9a9d YB |
35 | .interruptible = !lttng_regs_irqs_disabled(regs), |
36 | }; | |
149b9a9d YB |
37 | struct { |
38 | unsigned long ip; | |
56377c91 | 39 | } payload; |
149b9a9d | 40 | |
e2d5dbc7 MD |
41 | switch (event->type) { |
42 | case LTTNG_KERNEL_EVENT_TYPE_RECORDER: | |
43 | { | |
44 | struct lttng_kernel_event_recorder *event_recorder = | |
45 | container_of(event, struct lttng_kernel_event_recorder, parent); | |
f7d06400 | 46 | struct lttng_kernel_channel_buffer *chan = event_recorder->chan; |
e2d5dbc7 | 47 | |
f7d06400 | 48 | if (unlikely(!LTTNG_READ_ONCE(chan->parent.session->active))) |
e2d5dbc7 | 49 | return 0; |
f7d06400 | 50 | if (unlikely(!LTTNG_READ_ONCE(chan->parent.enabled))) |
e2d5dbc7 MD |
51 | return 0; |
52 | break; | |
53 | } | |
54 | case LTTNG_KERNEL_EVENT_TYPE_NOTIFIER: | |
55 | break; | |
56 | default: | |
57 | WARN_ON_ONCE(1); | |
58 | } | |
9de67196 | 59 | |
e2d5dbc7 | 60 | if (unlikely(!LTTNG_READ_ONCE(event->enabled))) |
9de67196 FD |
61 | return 0; |
62 | ||
e2d5dbc7 MD |
63 | switch (event->type) { |
64 | case LTTNG_KERNEL_EVENT_TYPE_RECORDER: | |
65 | { | |
66 | struct lttng_kernel_event_recorder *event_recorder = | |
67 | container_of(event, struct lttng_kernel_event_recorder, parent); | |
f7d06400 | 68 | struct lttng_kernel_channel_buffer *chan = event_recorder->chan; |
8a57ec02 | 69 | struct lttng_kernel_ring_buffer_ctx ctx; |
e2d5dbc7 MD |
70 | int ret; |
71 | ||
b1199bd3 MD |
72 | lib_ring_buffer_ctx_init(&ctx, event_recorder, |
73 | sizeof(payload), lttng_alignof(payload), <tng_probe_ctx); | |
e2d5dbc7 | 74 | |
c2fb9c1c | 75 | ret = chan->ops->event_reserve(&ctx); |
e2d5dbc7 MD |
76 | if (ret < 0) |
77 | return 0; | |
78 | ||
79 | /* Event payload. */ | |
80 | payload.ip = (unsigned long)instruction_pointer(regs); | |
81 | ||
f5ffbd77 | 82 | chan->ops->event_write(&ctx, &payload, sizeof(payload), lttng_alignof(payload)); |
e2d5dbc7 MD |
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), | |
4697aac7 | 105 | false, false), |
6c8c025b MD |
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 | |
17806c46 | 117 | int lttng_create_uprobe_event(const char *name, struct lttng_kernel_event_common *event) |
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; |
17806c46 | 132 | event->priv->desc = desc; |
9de67196 FD |
133 | |
134 | return 0; | |
135 | ||
136 | error_str: | |
137 | kfree(desc); | |
138 | return ret; | |
139 | } | |
140 | ||
56377c91 FD |
141 | /* |
142 | * Returns the inode struct from the current task and an fd. The inode is | |
143 | * grabbed by this function and must be put once we are done with it using | |
144 | * iput(). | |
145 | */ | |
146 | static struct inode *get_inode_from_fd(int fd) | |
147 | { | |
148 | struct file *file; | |
149 | struct inode *inode; | |
150 | ||
151 | rcu_read_lock(); | |
152 | /* | |
153 | * Returns the file backing the given fd. Needs to be done inside an RCU | |
154 | * critical section. | |
155 | */ | |
0aebcd68 | 156 | file = lttng_lookup_fd_rcu(fd); |
56377c91 | 157 | if (file == NULL) { |
5a15f70c | 158 | printk(KERN_WARNING "LTTng: Cannot access file backing the fd(%d)\n", fd); |
56377c91 FD |
159 | inode = NULL; |
160 | goto error; | |
161 | } | |
162 | ||
163 | /* Grab a reference on the inode. */ | |
164 | inode = igrab(file->f_path.dentry->d_inode); | |
165 | if (inode == NULL) | |
5a15f70c | 166 | printk(KERN_WARNING "LTTng: Cannot grab a reference on the inode.\n"); |
56377c91 FD |
167 | error: |
168 | rcu_read_unlock(); | |
169 | return inode; | |
170 | } | |
171 | ||
83b802dc FD |
172 | |
173 | static | |
174 | int lttng_uprobes_add_callsite(struct lttng_uprobe *uprobe, | |
606828e4 | 175 | struct lttng_kernel_abi_event_callsite __user *callsite, |
83b802dc FD |
176 | int (*handler)(struct uprobe_consumer *self, struct pt_regs *regs), |
177 | void *priv_data) | |
149b9a9d | 178 | { |
3aed4dca FD |
179 | int ret = 0; |
180 | struct lttng_uprobe_handler *uprobe_handler; | |
181 | ||
83b802dc | 182 | if (!priv_data) { |
3aed4dca FD |
183 | ret = -EINVAL; |
184 | goto end; | |
185 | } | |
186 | ||
187 | uprobe_handler = kzalloc(sizeof(struct lttng_uprobe_handler), GFP_KERNEL); | |
188 | if (!uprobe_handler) { | |
5a15f70c | 189 | printk(KERN_WARNING "LTTng: Error allocating uprobe_handler"); |
3aed4dca FD |
190 | ret = -ENOMEM; |
191 | goto end; | |
192 | } | |
193 | ||
196bfc6a | 194 | /* Ensure the memory we just allocated don't notify page faults. */ |
263b6c88 | 195 | wrapper_vmalloc_sync_mappings(); |
3aed4dca | 196 | |
e2d5dbc7 | 197 | uprobe_handler->event = priv_data; |
83b802dc | 198 | uprobe_handler->up_consumer.handler = handler; |
3aed4dca FD |
199 | |
200 | ret = copy_from_user(&uprobe_handler->offset, &callsite->u.uprobe.offset, sizeof(uint64_t)); | |
201 | if (ret) { | |
202 | goto register_error; | |
203 | } | |
204 | ||
853f5b15 | 205 | ret = uprobe_register(uprobe->inode, |
3aed4dca FD |
206 | uprobe_handler->offset, &uprobe_handler->up_consumer); |
207 | if (ret) { | |
5a15f70c | 208 | printk(KERN_WARNING "LTTng: Error registering probe on inode %lu " |
83b802dc | 209 | "and offset 0x%llx\n", uprobe->inode->i_ino, |
3aed4dca FD |
210 | uprobe_handler->offset); |
211 | ret = -1; | |
212 | goto register_error; | |
213 | } | |
214 | ||
83b802dc | 215 | list_add(&uprobe_handler->node, &uprobe->head); |
3aed4dca FD |
216 | |
217 | return ret; | |
218 | ||
219 | register_error: | |
220 | kfree(uprobe_handler); | |
221 | end: | |
222 | return ret; | |
223 | } | |
3aed4dca | 224 | |
e2d5dbc7 | 225 | int lttng_uprobes_event_add_callsite(struct lttng_kernel_event_common *event, |
606828e4 | 226 | struct lttng_kernel_abi_event_callsite __user *callsite) |
83b802dc | 227 | { |
e2d5dbc7 MD |
228 | return lttng_uprobes_add_callsite(&event->priv->u.uprobe, callsite, |
229 | lttng_uprobes_event_handler_pre, event); | |
83b802dc FD |
230 | } |
231 | EXPORT_SYMBOL_GPL(lttng_uprobes_event_add_callsite); | |
232 | ||
233 | static | |
234 | int lttng_uprobes_register(struct lttng_uprobe *uprobe, int fd) | |
3aed4dca FD |
235 | { |
236 | int ret = 0; | |
56377c91 | 237 | struct inode *inode; |
149b9a9d | 238 | |
56377c91 FD |
239 | inode = get_inode_from_fd(fd); |
240 | if (!inode) { | |
5a15f70c | 241 | printk(KERN_WARNING "LTTng: Cannot get inode from fd\n"); |
56377c91 FD |
242 | ret = -EBADF; |
243 | goto inode_error; | |
244 | } | |
83b802dc FD |
245 | uprobe->inode = inode; |
246 | INIT_LIST_HEAD(&uprobe->head); | |
247 | ||
248 | inode_error: | |
249 | return ret; | |
250 | } | |
251 | ||
17806c46 | 252 | int lttng_uprobes_register_event(const char *name, int fd, struct lttng_kernel_event_common *event) |
83b802dc FD |
253 | { |
254 | int ret = 0; | |
255 | ||
17806c46 | 256 | ret = lttng_create_uprobe_event(name, event); |
83b802dc FD |
257 | if (ret) |
258 | goto error; | |
259 | ||
17806c46 | 260 | ret = lttng_uprobes_register(&event->priv->u.uprobe, fd); |
83b802dc FD |
261 | if (ret) |
262 | goto register_error; | |
149b9a9d | 263 | |
149b9a9d YB |
264 | return 0; |
265 | ||
83b802dc | 266 | register_error: |
17806c46 MD |
267 | kfree(event->priv->desc->event_name); |
268 | kfree(event->priv->desc); | |
149b9a9d YB |
269 | error: |
270 | return ret; | |
271 | } | |
83b802dc | 272 | EXPORT_SYMBOL_GPL(lttng_uprobes_register_event); |
149b9a9d | 273 | |
9de67196 FD |
274 | static |
275 | void lttng_uprobes_unregister(struct inode *inode, struct list_head *head) | |
149b9a9d | 276 | { |
3aed4dca FD |
277 | struct lttng_uprobe_handler *iter, *tmp; |
278 | ||
279 | /* | |
280 | * Iterate over the list of handler, remove each handler from the list | |
281 | * and free the struct. | |
282 | */ | |
9de67196 | 283 | list_for_each_entry_safe(iter, tmp, head, node) { |
853f5b15 | 284 | uprobe_unregister(inode, iter->offset, &iter->up_consumer); |
3aed4dca FD |
285 | list_del(&iter->node); |
286 | kfree(iter); | |
287 | } | |
9de67196 FD |
288 | } |
289 | ||
17806c46 | 290 | void lttng_uprobes_unregister_event(struct lttng_kernel_event_common *event) |
9de67196 | 291 | { |
17806c46 | 292 | lttng_uprobes_unregister(event->priv->u.uprobe.inode, &event->priv->u.uprobe.head); |
149b9a9d | 293 | } |
83b802dc | 294 | EXPORT_SYMBOL_GPL(lttng_uprobes_unregister_event); |
149b9a9d | 295 | |
17806c46 | 296 | void lttng_uprobes_destroy_event_private(struct lttng_kernel_event_common *event) |
149b9a9d | 297 | { |
17806c46 MD |
298 | iput(event->priv->u.uprobe.inode); |
299 | kfree(event->priv->desc->event_name); | |
300 | kfree(event->priv->desc); | |
149b9a9d | 301 | } |
83b802dc | 302 | EXPORT_SYMBOL_GPL(lttng_uprobes_destroy_event_private); |
149b9a9d | 303 | |
a67ba386 | 304 | void lttng_uprobes_destroy_event_notifier_private(struct lttng_kernel_event_notifier *event_notifier) |
9de67196 | 305 | { |
a67ba386 MD |
306 | iput(event_notifier->priv->parent.u.uprobe.inode); |
307 | kfree(event_notifier->priv->parent.desc->event_name); | |
308 | kfree(event_notifier->priv->parent.desc); | |
9de67196 FD |
309 | } |
310 | EXPORT_SYMBOL_GPL(lttng_uprobes_destroy_event_notifier_private); | |
311 | ||
149b9a9d YB |
312 | MODULE_LICENSE("GPL and additional rights"); |
313 | MODULE_AUTHOR("Yannick Brosseau"); | |
314 | MODULE_DESCRIPTION("Linux Trace Toolkit Uprobes Support"); |