Commit | Line | Data |
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baf20995 MD |
1 | /* |
2 | * ltt-debugfs-abi.c | |
3 | * | |
4 | * Copyright 2010 (c) - Mathieu Desnoyers <mathieu.desnoyers@efficios.com> | |
5 | * | |
6 | * LTTng debugfs ABI | |
7 | * | |
8 | * Mimic system calls for: | |
9 | * - session creation, returns a file descriptor or failure. | |
ad1c05e1 MD |
10 | * - channel creation, returns a file descriptor or failure. |
11 | * - Operates on a session file descriptor | |
12 | * - Takes all channel options as parameters. | |
13 | * - stream get, returns a file descriptor or failure. | |
14 | * - Operates on a channel file descriptor. | |
15 | * - stream notifier get, returns a file descriptor or failure. | |
16 | * - Operates on a channel file descriptor. | |
17 | * - event creation, returns a file descriptor or failure. | |
18 | * - Operates on a channel file descriptor | |
19 | * - Takes an event name as parameter | |
20 | * - Takes an instrumentation source as parameter | |
21 | * - e.g. tracepoints, dynamic_probes... | |
22 | * - Takes instrumentation source specific arguments. | |
baf20995 MD |
23 | */ |
24 | ||
25 | #include <linux/debugfs.h> | |
ad1c05e1 | 26 | #include "ltt-events.h" |
baf20995 MD |
27 | |
28 | /* | |
29 | * This is LTTng's own personal way to create a system call as an external | |
30 | * module. We use ioctl() on /sys/kernel/debug/lttng. | |
31 | */ | |
32 | ||
33 | static struct dentry *lttng_dentry; | |
ad1c05e1 MD |
34 | static const struct file_operations lttng_fops; |
35 | static const struct file_operations lttng_session_fops; | |
36 | static const struct file_operations lttng_channel_fops; | |
305d3e42 | 37 | static const struct file_operations lttng_event_fops; |
baf20995 MD |
38 | |
39 | /* | |
40 | * LTTng DebugFS ABI structures. | |
41 | */ | |
42 | ||
43 | struct lttng_channel { | |
baf20995 MD |
44 | int overwrite; /* 1: overwrite, 0: discard */ |
45 | u64 subbuf_size; | |
46 | u64 num_subbuf; | |
47 | unsigned int switch_timer_interval; | |
48 | unsigned int read_timer_interval; | |
49 | }; | |
50 | ||
51 | struct lttng_event { | |
baf20995 MD |
52 | enum instrum_type itype; |
53 | char name[]; | |
54 | }; | |
55 | ||
ad1c05e1 | 56 | static |
baf20995 MD |
57 | int lttng_abi_create_session(void) |
58 | { | |
59 | struct ltt_session *session; | |
c0e31d2e | 60 | struct file *session_file; |
baf20995 MD |
61 | int session_fd; |
62 | ||
653fe716 | 63 | session = ltt_session_create(); |
baf20995 MD |
64 | if (!session) |
65 | return -ENOMEM; | |
66 | session_fd = get_unused_fd_flags(O_RDWR); | |
67 | if (session_fd < 0) { | |
68 | ret = session_fd; | |
69 | goto fd_error; | |
70 | } | |
c0e31d2e | 71 | session_file = anon_inode_getfile("[lttng_session]", |
ad1c05e1 | 72 | <tng_session_fops, |
baf20995 | 73 | session, O_RDWR); |
c0e31d2e MD |
74 | if (IS_ERR(session_file)) { |
75 | ret = PTR_ERR(session_file); | |
baf20995 MD |
76 | goto file_error; |
77 | } | |
c0e31d2e MD |
78 | session->file = session_file; |
79 | fd_install(session_fd, session_file); | |
baf20995 MD |
80 | return session_fd; |
81 | ||
82 | file_error: | |
83 | put_unused_fd(session_fd); | |
84 | fd_error: | |
85 | ltt_session_destroy(session); | |
86 | return ret; | |
87 | } | |
88 | ||
ad1c05e1 MD |
89 | /** |
90 | * lttng_ioctl - lttng syscall through ioctl | |
91 | * | |
c0e31d2e | 92 | * @file: the file |
ad1c05e1 MD |
93 | * @cmd: the command |
94 | * @arg: command arg | |
95 | * | |
96 | * This ioctl implements lttng commands: | |
97 | * LTTNG_SESSION | |
98 | * Returns a LTTng trace session file descriptor | |
99 | * | |
100 | * The returned session will be deleted when its file descriptor is closed. | |
101 | */ | |
102 | static | |
c0e31d2e | 103 | long lttng_ioctl(struct file *file, unsigned int cmd, unsigned long arg) |
ad1c05e1 MD |
104 | { |
105 | switch (cmd) { | |
106 | case LTTNG_SESSION: | |
107 | return lttng_abi_create_session(); | |
108 | default: | |
109 | return -ENOIOCTLCMD; | |
110 | } | |
111 | } | |
112 | ||
ad1c05e1 MD |
113 | static const struct file_operations lttng_fops = { |
114 | .unlocked_ioctl = lttng_ioctl, | |
115 | #ifdef CONFIG_COMPAT | |
03037b98 | 116 | .compat_ioctl = lttng_ioctl, |
ad1c05e1 MD |
117 | #endif |
118 | } | |
119 | ||
c0e31d2e | 120 | int lttng_abi_create_channel(struct file *session_file, |
ad1c05e1 | 121 | struct lttng_channel __user *uchan_param) |
baf20995 | 122 | { |
c0e31d2e | 123 | struct ltt_session *session = session_file->private_data; |
baf20995 | 124 | struct ltt_channel *chan; |
c0e31d2e | 125 | struct file *chan_file; |
baf20995 MD |
126 | struct lttng_channel chan_param; |
127 | int chan_fd; | |
ad1c05e1 | 128 | int ret = 0; |
baf20995 | 129 | |
653fe716 | 130 | if (copy_from_user(&chan_param, uchan_param, sizeof(chan_param))) |
baf20995 | 131 | return -EFAULT; |
baf20995 MD |
132 | chan_fd = get_unused_fd_flags(O_RDWR); |
133 | if (chan_fd < 0) { | |
134 | ret = chan_fd; | |
135 | goto fd_error; | |
136 | } | |
c0e31d2e | 137 | chan_file = anon_inode_getfile("[lttng_channel]", |
ad1c05e1 | 138 | <tng_channel_fops, |
03037b98 | 139 | NULL, O_RDWR); |
c0e31d2e MD |
140 | if (IS_ERR(chan_file)) { |
141 | ret = PTR_ERR(chan_file); | |
baf20995 MD |
142 | goto file_error; |
143 | } | |
03037b98 MD |
144 | /* |
145 | * We tolerate no failure path after channel creation. It will stay | |
146 | * invariant for the rest of the session. | |
147 | */ | |
148 | chan = ltt_channel_create(session, chan_param->overwrite, NULL, | |
149 | chan_param->subbuf_size, | |
150 | chan_param->num_subbuf, | |
151 | chan_param->switch_timer_interval, | |
152 | chan_param->read_timer_interval); | |
153 | if (!chan) { | |
154 | ret = -ENOMEM; | |
155 | goto chan_error; | |
156 | } | |
c0e31d2e MD |
157 | channel->file = chan_file; |
158 | chan_file->private_data = chan; | |
159 | fd_install(chan_fd, chan_file); | |
ad1c05e1 | 160 | /* The channel created holds a reference on the session */ |
c0e31d2e | 161 | atomic_inc(&session_file->f_count); |
ad1c05e1 | 162 | |
baf20995 MD |
163 | return chan_fd; |
164 | ||
03037b98 | 165 | chan_error: |
c0e31d2e | 166 | fput(chan_file); |
baf20995 MD |
167 | file_error: |
168 | put_unused_fd(chan_fd); | |
169 | fd_error: | |
baf20995 MD |
170 | return ret; |
171 | } | |
172 | ||
173 | /** | |
ad1c05e1 | 174 | * lttng_session_ioctl - lttng session fd ioctl |
baf20995 | 175 | * |
c0e31d2e | 176 | * @file: the file |
baf20995 MD |
177 | * @cmd: the command |
178 | * @arg: command arg | |
179 | * | |
180 | * This ioctl implements lttng commands: | |
baf20995 MD |
181 | * LTTNG_CHANNEL |
182 | * Returns a LTTng channel file descriptor | |
ad1c05e1 MD |
183 | * |
184 | * The returned channel will be deleted when its file descriptor is closed. | |
185 | */ | |
186 | static | |
c0e31d2e | 187 | long lttng_session_ioctl(struct file *file, unsigned int cmd, unsigned long arg) |
ad1c05e1 | 188 | { |
c0e31d2e MD |
189 | struct ltt_session *session = file->private_data; |
190 | ||
ad1c05e1 MD |
191 | switch (cmd) { |
192 | case LTTNG_CHANNEL: | |
c0e31d2e MD |
193 | return lttng_abi_create_channel(file, (struct lttng_channel __user *)arg); |
194 | case LTTNG_SESSION_START: | |
195 | return ltt_session_start(session); | |
196 | case LTTNG_SESSION_STOP: | |
197 | return ltt_session_stop(session); | |
198 | case LTTNG_SESSION_FINALIZE: | |
199 | return ltt_session_finalize(session); | |
ad1c05e1 MD |
200 | default: |
201 | return -ENOIOCTLCMD; | |
202 | } | |
203 | } | |
204 | ||
03037b98 MD |
205 | /* |
206 | * Called when the last file reference is dropped. | |
207 | * | |
208 | * Big fat note: channels and events are invariant for the whole session after | |
209 | * their creation. So this session destruction also destroys all channel and | |
210 | * event structures specific to this session (they are not destroyed when their | |
211 | * individual file is released). | |
212 | */ | |
ad1c05e1 | 213 | static |
03037b98 | 214 | int lttng_session_release(struct inode *inode, struct file *file) |
ad1c05e1 | 215 | { |
03037b98 MD |
216 | struct ltt_session *session = file->private_data; |
217 | return ltt_session_destroy(session); | |
ad1c05e1 | 218 | } |
ad1c05e1 MD |
219 | |
220 | static const struct file_operations lttng_session_fops = { | |
03037b98 | 221 | .release = lttng_session_release, |
ad1c05e1 MD |
222 | .unlocked_ioctl = lttng_session_ioctl, |
223 | #ifdef CONFIG_COMPAT | |
03037b98 | 224 | .compat_ioctl = lttng_session_ioctl, |
ad1c05e1 MD |
225 | #endif |
226 | } | |
227 | ||
228 | static | |
c0e31d2e | 229 | int lttng_abi_open_stream(struct file *channel_file) |
ad1c05e1 | 230 | { |
c0e31d2e | 231 | struct ltt_channel *channel = channel_file->private_data; |
ad1c05e1 MD |
232 | struct lib_ring_buffer *buf; |
233 | int stream_fd, ret; | |
234 | ||
235 | buf = ltt_buffer_read_open(channel->chan); | |
236 | if (!buf) | |
237 | return -ENOENT; | |
238 | ||
239 | stream_fd = get_unused_fd_flags(O_RDWR); | |
240 | if (stream_fd < 0) { | |
241 | ret = stream_fd; | |
242 | goto fd_error; | |
243 | } | |
c0e31d2e | 244 | stream_file = anon_inode_getfile("[lttng_stream]", |
7f57c73c | 245 | &lib_ring_buffer_file_operations, |
ad1c05e1 | 246 | buf, O_RDWR); |
c0e31d2e MD |
247 | if (IS_ERR(stream_file)) { |
248 | ret = PTR_ERR(stream_file); | |
ad1c05e1 MD |
249 | goto file_error; |
250 | } | |
c0e31d2e | 251 | fd_install(stream_fd, stream_file); |
ad1c05e1 | 252 | /* The stream holds a reference on the channel */ |
c0e31d2e | 253 | atomic_inc(&channel_file->f_count); |
ad1c05e1 MD |
254 | return stream_fd; |
255 | ||
256 | file_error: | |
257 | put_unused_fd(stream_fd); | |
258 | fd_error: | |
259 | ltt_buffer_read_close(buf); | |
260 | return ret; | |
261 | } | |
262 | ||
653fe716 | 263 | static |
c0e31d2e | 264 | int lttng_abi_create_event(struct file *channel_file, |
653fe716 MD |
265 | struct lttng_event __user *uevent_param) |
266 | { | |
c0e31d2e | 267 | struct ltt_channel *channel = channel_file->private_data; |
653fe716 MD |
268 | struct ltt_event *event; |
269 | char *event_name; | |
270 | struct lttng_event event_param; | |
271 | int event_fd, ret; | |
272 | ||
273 | if (copy_from_user(&event_param, uevent_param, sizeof(event_param))) | |
274 | return -EFAULT; | |
275 | event_name = kmalloc(PATH_MAX, GFP_KERNEL); | |
276 | if (!event_name) | |
277 | return -ENOMEM; | |
278 | if (strncpy_from_user(event_name, &uevent_param->name, PATH_MAX)) { | |
279 | ret = -EFAULT; | |
280 | goto name_error; | |
281 | } | |
282 | event_name[PATH_MAX - 1] = '\0'; | |
653fe716 MD |
283 | event_fd = get_unused_fd_flags(O_RDWR); |
284 | if (event_fd < 0) { | |
285 | ret = event_fd; | |
286 | goto fd_error; | |
287 | } | |
c0e31d2e | 288 | event_file = anon_inode_getfile("[lttng_event]", |
305d3e42 | 289 | <tng_event_fops, /* TODO: filter */ |
03037b98 | 290 | NULL, O_RDWR); |
c0e31d2e MD |
291 | if (IS_ERR(event_file)) { |
292 | ret = PTR_ERR(event_file); | |
653fe716 MD |
293 | goto file_error; |
294 | } | |
03037b98 MD |
295 | /* |
296 | * We tolerate no failure path after event creation. It will stay | |
297 | * invariant for the rest of the session. | |
298 | */ | |
299 | event = ltt_event_create(channel, event_param->itype, event_name, NULL); | |
300 | if (!event) { | |
301 | goto event_error; | |
302 | ret = -EEXIST; | |
303 | } | |
c0e31d2e MD |
304 | event_file->private_data = event; |
305 | fd_install(event_fd, event_file); | |
653fe716 | 306 | /* The event holds a reference on the channel */ |
c0e31d2e | 307 | atomic_inc(&channel_file->f_count); |
03037b98 | 308 | kfree(event_name); |
653fe716 MD |
309 | return event_fd; |
310 | ||
03037b98 | 311 | event_error: |
c0e31d2e | 312 | fput(event_file); |
653fe716 MD |
313 | file_error: |
314 | put_unused_fd(event_fd); | |
315 | fd_error: | |
653fe716 MD |
316 | name_error: |
317 | kfree(event_name); | |
318 | return ret; | |
319 | } | |
ad1c05e1 MD |
320 | |
321 | /** | |
322 | * lttng_channel_ioctl - lttng syscall through ioctl | |
323 | * | |
c0e31d2e | 324 | * @file: the file |
ad1c05e1 MD |
325 | * @cmd: the command |
326 | * @arg: command arg | |
327 | * | |
328 | * This ioctl implements lttng commands: | |
329 | * LTTNG_STREAM | |
330 | * Returns an event stream file descriptor or failure. | |
331 | * (typically, one event stream records events from one CPU) | |
baf20995 | 332 | * LTTNG_EVENT |
ad1c05e1 | 333 | * Returns an event file descriptor or failure. |
baf20995 MD |
334 | * |
335 | * The returned session will be deleted when its file descriptor is closed. | |
336 | * Channel and event file descriptors also hold a reference on the session. | |
337 | */ | |
ad1c05e1 | 338 | static |
c0e31d2e | 339 | long lttng_channel_ioctl(struct file *file, unsigned int cmd, unsigned long arg) |
baf20995 | 340 | { |
baf20995 | 341 | switch (cmd) { |
ad1c05e1 | 342 | case LTTNG_STREAM: |
c0e31d2e | 343 | return lttng_abi_open_stream(file); |
baf20995 | 344 | case LTTNG_EVENT: |
c0e31d2e | 345 | return lttng_abi_create_event(file, (struct lttng_event __user *)arg); |
baf20995 MD |
346 | default: |
347 | return -ENOIOCTLCMD; | |
348 | } | |
349 | } | |
350 | ||
653fe716 MD |
351 | /** |
352 | * lttng_channel_poll - lttng stream addition/removal monitoring | |
353 | * | |
c0e31d2e | 354 | * @file: the file |
653fe716 MD |
355 | * @wait: poll table |
356 | */ | |
c0e31d2e | 357 | unsigned int lttng_channel_poll(struct file *file, poll_table *wait) |
653fe716 | 358 | { |
c0e31d2e | 359 | struct ltt_channel *channel = file->private_data; |
653fe716 MD |
360 | unsigned int mask = 0; |
361 | ||
c0e31d2e | 362 | if (file->f_mode & FMODE_READ) { |
653fe716 | 363 | poll_wait_set_exclusive(wait); |
c0e31d2e | 364 | poll_wait(file, &channel->notify_wait, wait); |
653fe716 MD |
365 | |
366 | /* TODO: identify when the channel is being finalized. */ | |
367 | if (finalized) | |
368 | return POLLHUP; | |
369 | else | |
370 | return POLLIN | POLLRDNORM; | |
371 | } | |
372 | return mask; | |
373 | ||
374 | } | |
375 | ||
0a84a57f MD |
376 | static |
377 | int lttng_channel_release(struct inode *inode, struct file *file) | |
378 | { | |
379 | struct ltt_channel *channel = file->private_data; | |
380 | fput(channel->session->file); | |
381 | return 0; | |
382 | } | |
383 | ||
ad1c05e1 | 384 | static const struct file_operations lttng_channel_fops = { |
03037b98 | 385 | .release = lttng_channel_release, |
653fe716 | 386 | .poll = lttng_channel_poll, |
ad1c05e1 | 387 | .unlocked_ioctl = lttng_channel_ioctl, |
baf20995 | 388 | #ifdef CONFIG_COMPAT |
03037b98 | 389 | .compat_ioctl = lttng_channel_ioctl, |
baf20995 MD |
390 | #endif |
391 | } | |
392 | ||
0a84a57f MD |
393 | static |
394 | int lttng_event_release(struct inode *inode, struct file *file) | |
395 | { | |
396 | struct ltt_event *event = file->private_data; | |
397 | fput(event->chan->file); | |
398 | return 0; | |
399 | } | |
400 | ||
401 | static const struct file_operations lttng_event_fops = { | |
402 | .release = lttng_event_release, | |
403 | } | |
404 | ||
baf20995 MD |
405 | static int __init ltt_debugfs_abi_init(void) |
406 | { | |
407 | int ret = 0; | |
408 | ||
409 | lttng_dentry = debugfs_create_file("lttng", NULL); | |
410 | if (IS_ERR(lttng_dentry) || !lttng_dentry) | |
411 | printk(KERN_ERR "Error creating LTTng control file\n"); | |
412 | ret = -ENOMEM; | |
413 | goto error; | |
414 | } | |
415 | error: | |
416 | return ret; | |
417 | } | |
418 | ||
419 | static void __exit ltt_debugfs_abi_exit(void) | |
420 | { | |
421 | debugfs_remote(lttng_dentry); | |
422 | } |