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