Commit | Line | Data |
---|---|---|
b7cdc182 | 1 | /* SPDX-License-Identifier: (GPL-2.0-only OR LGPL-2.1-only) |
9f36eaed | 2 | * |
f3bc08c5 MD |
3 | * ring_buffer_vfs.c |
4 | * | |
f3bc08c5 MD |
5 | * Ring Buffer VFS file operations. |
6 | * | |
886d51a3 | 7 | * Copyright (C) 2010-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com> |
f3bc08c5 MD |
8 | */ |
9 | ||
10 | #include <linux/module.h> | |
11 | #include <linux/fs.h> | |
12 | #include <linux/compat.h> | |
13 | ||
c075712b MD |
14 | #include <wrapper/ringbuffer/backend.h> |
15 | #include <wrapper/ringbuffer/frontend.h> | |
16 | #include <wrapper/ringbuffer/vfs.h> | |
c075712b | 17 | #include <lttng-tracer.h> |
f3bc08c5 MD |
18 | |
19 | static int put_ulong(unsigned long val, unsigned long arg) | |
20 | { | |
21 | return put_user(val, (unsigned long __user *)arg); | |
22 | } | |
23 | ||
24 | #ifdef CONFIG_COMPAT | |
25 | static int compat_put_ulong(compat_ulong_t val, unsigned long arg) | |
26 | { | |
27 | return put_user(val, (compat_ulong_t __user *)compat_ptr(arg)); | |
28 | } | |
29 | #endif | |
30 | ||
b3b8072b MD |
31 | /* |
32 | * This is not used by anonymous file descriptors. This code is left | |
33 | * there if we ever want to implement an inode with open() operation. | |
34 | */ | |
d83004aa JD |
35 | int lib_ring_buffer_open(struct inode *inode, struct file *file, |
36 | struct lib_ring_buffer *buf) | |
f3bc08c5 | 37 | { |
f3bc08c5 MD |
38 | int ret; |
39 | ||
733ce41d MD |
40 | if (!buf) |
41 | return -EINVAL; | |
42 | ||
f3bc08c5 MD |
43 | ret = lib_ring_buffer_open_read(buf); |
44 | if (ret) | |
45 | return ret; | |
46 | ||
f3bc08c5 MD |
47 | ret = nonseekable_open(inode, file); |
48 | if (ret) | |
49 | goto release_read; | |
50 | return 0; | |
51 | ||
52 | release_read: | |
53 | lib_ring_buffer_release_read(buf); | |
54 | return ret; | |
55 | } | |
d83004aa | 56 | EXPORT_SYMBOL_GPL(lib_ring_buffer_open); |
f3bc08c5 MD |
57 | |
58 | /** | |
d83004aa | 59 | * vfs_lib_ring_buffer_open - ring buffer open file operation |
f3bc08c5 MD |
60 | * @inode: opened inode |
61 | * @file: opened file | |
62 | * | |
d83004aa JD |
63 | * Open implementation. Makes sure only one open instance of a buffer is |
64 | * done at a given moment. | |
f3bc08c5 | 65 | */ |
d83004aa JD |
66 | static |
67 | int vfs_lib_ring_buffer_open(struct inode *inode, struct file *file) | |
f3bc08c5 | 68 | { |
d83004aa JD |
69 | struct lib_ring_buffer *buf = inode->i_private; |
70 | ||
71 | file->private_data = buf; | |
72 | return lib_ring_buffer_open(inode, file, buf); | |
73 | } | |
f3bc08c5 | 74 | |
d83004aa JD |
75 | int lib_ring_buffer_release(struct inode *inode, struct file *file, |
76 | struct lib_ring_buffer *buf) | |
77 | { | |
f3bc08c5 MD |
78 | lib_ring_buffer_release_read(buf); |
79 | ||
80 | return 0; | |
81 | } | |
d83004aa | 82 | EXPORT_SYMBOL_GPL(lib_ring_buffer_release); |
f3bc08c5 MD |
83 | |
84 | /** | |
d83004aa JD |
85 | * vfs_lib_ring_buffer_release - ring buffer release file operation |
86 | * @inode: opened inode | |
87 | * @file: opened file | |
f3bc08c5 | 88 | * |
d83004aa | 89 | * Release implementation. |
f3bc08c5 | 90 | */ |
d83004aa JD |
91 | static |
92 | int vfs_lib_ring_buffer_release(struct inode *inode, struct file *file) | |
93 | { | |
94 | struct lib_ring_buffer *buf = file->private_data; | |
95 | ||
96 | return lib_ring_buffer_release(inode, file, buf); | |
97 | } | |
98 | ||
99 | unsigned int lib_ring_buffer_poll(struct file *filp, poll_table *wait, | |
100 | struct lib_ring_buffer *buf) | |
f3bc08c5 MD |
101 | { |
102 | unsigned int mask = 0; | |
f3bc08c5 | 103 | struct channel *chan = buf->backend.chan; |
5a8fd222 | 104 | const struct lib_ring_buffer_config *config = &chan->backend.config; |
254ec7bc | 105 | int finalized, disabled; |
f3bc08c5 MD |
106 | |
107 | if (filp->f_mode & FMODE_READ) { | |
f3bc08c5 MD |
108 | poll_wait(filp, &buf->read_wait, wait); |
109 | ||
110 | finalized = lib_ring_buffer_is_finalized(config, buf); | |
254ec7bc MD |
111 | disabled = lib_ring_buffer_channel_is_disabled(chan); |
112 | ||
f3bc08c5 MD |
113 | /* |
114 | * lib_ring_buffer_is_finalized() contains a smp_rmb() ordering | |
115 | * finalized load before offsets loads. | |
116 | */ | |
117 | WARN_ON(atomic_long_read(&buf->active_readers) != 1); | |
118 | retry: | |
254ec7bc MD |
119 | if (disabled) |
120 | return POLLERR; | |
121 | ||
f3bc08c5 MD |
122 | if (subbuf_trunc(lib_ring_buffer_get_offset(config, buf), chan) |
123 | - subbuf_trunc(lib_ring_buffer_get_consumed(config, buf), chan) | |
124 | == 0) { | |
125 | if (finalized) | |
126 | return POLLHUP; | |
127 | else { | |
128 | /* | |
129 | * The memory barriers | |
130 | * __wait_event()/wake_up_interruptible() take | |
131 | * care of "raw_spin_is_locked" memory ordering. | |
132 | */ | |
133 | if (raw_spin_is_locked(&buf->raw_tick_nohz_spinlock)) | |
134 | goto retry; | |
135 | else | |
136 | return 0; | |
137 | } | |
138 | } else { | |
139 | if (subbuf_trunc(lib_ring_buffer_get_offset(config, buf), | |
140 | chan) | |
141 | - subbuf_trunc(lib_ring_buffer_get_consumed(config, buf), | |
142 | chan) | |
143 | >= chan->backend.buf_size) | |
144 | return POLLPRI | POLLRDBAND; | |
145 | else | |
146 | return POLLIN | POLLRDNORM; | |
147 | } | |
148 | } | |
149 | return mask; | |
150 | } | |
d83004aa | 151 | EXPORT_SYMBOL_GPL(lib_ring_buffer_poll); |
f3bc08c5 MD |
152 | |
153 | /** | |
d83004aa | 154 | * vfs_lib_ring_buffer_poll - ring buffer poll file operation |
f3bc08c5 | 155 | * @filp: the file |
d83004aa | 156 | * @wait: poll table |
f3bc08c5 | 157 | * |
d83004aa | 158 | * Poll implementation. |
f3bc08c5 | 159 | */ |
d83004aa JD |
160 | static |
161 | unsigned int vfs_lib_ring_buffer_poll(struct file *filp, poll_table *wait) | |
f3bc08c5 MD |
162 | { |
163 | struct lib_ring_buffer *buf = filp->private_data; | |
d83004aa JD |
164 | |
165 | return lib_ring_buffer_poll(filp, wait, buf); | |
166 | } | |
167 | ||
168 | long lib_ring_buffer_ioctl(struct file *filp, unsigned int cmd, | |
169 | unsigned long arg, struct lib_ring_buffer *buf) | |
170 | { | |
f3bc08c5 | 171 | struct channel *chan = buf->backend.chan; |
5a8fd222 | 172 | const struct lib_ring_buffer_config *config = &chan->backend.config; |
f3bc08c5 | 173 | |
254ec7bc MD |
174 | if (lib_ring_buffer_channel_is_disabled(chan)) |
175 | return -EIO; | |
176 | ||
f3bc08c5 MD |
177 | switch (cmd) { |
178 | case RING_BUFFER_SNAPSHOT: | |
179 | return lib_ring_buffer_snapshot(buf, &buf->cons_snapshot, | |
180 | &buf->prod_snapshot); | |
4dce5a48 JG |
181 | case RING_BUFFER_SNAPSHOT_SAMPLE_POSITIONS: |
182 | return lib_ring_buffer_snapshot_sample_positions(buf, | |
183 | &buf->cons_snapshot, &buf->prod_snapshot); | |
f3bc08c5 MD |
184 | case RING_BUFFER_SNAPSHOT_GET_CONSUMED: |
185 | return put_ulong(buf->cons_snapshot, arg); | |
186 | case RING_BUFFER_SNAPSHOT_GET_PRODUCED: | |
187 | return put_ulong(buf->prod_snapshot, arg); | |
188 | case RING_BUFFER_GET_SUBBUF: | |
189 | { | |
190 | unsigned long uconsume; | |
191 | long ret; | |
192 | ||
193 | ret = get_user(uconsume, (unsigned long __user *) arg); | |
194 | if (ret) | |
195 | return ret; /* will return -EFAULT */ | |
196 | ret = lib_ring_buffer_get_subbuf(buf, uconsume); | |
197 | if (!ret) { | |
198 | /* Set file position to zero at each successful "get" */ | |
199 | filp->f_pos = 0; | |
200 | } | |
201 | return ret; | |
202 | } | |
203 | case RING_BUFFER_PUT_SUBBUF: | |
204 | lib_ring_buffer_put_subbuf(buf); | |
205 | return 0; | |
206 | ||
207 | case RING_BUFFER_GET_NEXT_SUBBUF: | |
208 | { | |
209 | long ret; | |
210 | ||
211 | ret = lib_ring_buffer_get_next_subbuf(buf); | |
212 | if (!ret) { | |
213 | /* Set file position to zero at each successful "get" */ | |
214 | filp->f_pos = 0; | |
215 | } | |
216 | return ret; | |
217 | } | |
218 | case RING_BUFFER_PUT_NEXT_SUBBUF: | |
219 | lib_ring_buffer_put_next_subbuf(buf); | |
220 | return 0; | |
221 | case RING_BUFFER_GET_SUBBUF_SIZE: | |
222 | return put_ulong(lib_ring_buffer_get_read_data_size(config, buf), | |
223 | arg); | |
224 | case RING_BUFFER_GET_PADDED_SUBBUF_SIZE: | |
225 | { | |
226 | unsigned long size; | |
227 | ||
228 | size = lib_ring_buffer_get_read_data_size(config, buf); | |
229 | size = PAGE_ALIGN(size); | |
230 | return put_ulong(size, arg); | |
231 | } | |
232 | case RING_BUFFER_GET_MAX_SUBBUF_SIZE: | |
233 | return put_ulong(chan->backend.subbuf_size, arg); | |
234 | case RING_BUFFER_GET_MMAP_LEN: | |
235 | { | |
236 | unsigned long mmap_buf_len; | |
237 | ||
238 | if (config->output != RING_BUFFER_MMAP) | |
239 | return -EINVAL; | |
240 | mmap_buf_len = chan->backend.buf_size; | |
241 | if (chan->backend.extra_reader_sb) | |
242 | mmap_buf_len += chan->backend.subbuf_size; | |
243 | if (mmap_buf_len > INT_MAX) | |
244 | return -EFBIG; | |
245 | return put_ulong(mmap_buf_len, arg); | |
246 | } | |
247 | case RING_BUFFER_GET_MMAP_READ_OFFSET: | |
248 | { | |
249 | unsigned long sb_bindex; | |
250 | ||
251 | if (config->output != RING_BUFFER_MMAP) | |
252 | return -EINVAL; | |
253 | sb_bindex = subbuffer_id_get_index(config, | |
254 | buf->backend.buf_rsb.id); | |
255 | return put_ulong(buf->backend.array[sb_bindex]->mmap_offset, | |
256 | arg); | |
257 | } | |
5c055266 | 258 | case RING_BUFFER_FLUSH: |
5e391252 | 259 | lib_ring_buffer_switch_remote(buf); |
5c055266 | 260 | return 0; |
c6f05468 MD |
261 | case RING_BUFFER_FLUSH_EMPTY: |
262 | lib_ring_buffer_switch_remote_empty(buf); | |
263 | return 0; | |
c245d0d3 MD |
264 | case RING_BUFFER_CLEAR: |
265 | lib_ring_buffer_clear(buf); | |
266 | return 0; | |
f3bc08c5 MD |
267 | default: |
268 | return -ENOIOCTLCMD; | |
269 | } | |
270 | } | |
d83004aa JD |
271 | EXPORT_SYMBOL_GPL(lib_ring_buffer_ioctl); |
272 | ||
273 | /** | |
274 | * vfs_lib_ring_buffer_ioctl - control ring buffer reader synchronization | |
275 | * | |
276 | * @filp: the file | |
277 | * @cmd: the command | |
278 | * @arg: command arg | |
279 | * | |
280 | * This ioctl implements commands necessary for producer/consumer | |
281 | * and flight recorder reader interaction : | |
282 | * RING_BUFFER_GET_NEXT_SUBBUF | |
283 | * Get the next sub-buffer that can be read. It never blocks. | |
284 | * RING_BUFFER_PUT_NEXT_SUBBUF | |
285 | * Release the currently read sub-buffer. | |
286 | * RING_BUFFER_GET_SUBBUF_SIZE | |
287 | * returns the size of the current sub-buffer. | |
288 | * RING_BUFFER_GET_MAX_SUBBUF_SIZE | |
289 | * returns the maximum size for sub-buffers. | |
290 | * RING_BUFFER_GET_NUM_SUBBUF | |
291 | * returns the number of reader-visible sub-buffers in the per cpu | |
292 | * channel (for mmap). | |
293 | * RING_BUFFER_GET_MMAP_READ_OFFSET | |
294 | * returns the offset of the subbuffer belonging to the reader. | |
295 | * Should only be used for mmap clients. | |
296 | */ | |
297 | static | |
298 | long vfs_lib_ring_buffer_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) | |
299 | { | |
300 | struct lib_ring_buffer *buf = filp->private_data; | |
301 | ||
302 | return lib_ring_buffer_ioctl(filp, cmd, arg, buf); | |
303 | } | |
f3bc08c5 MD |
304 | |
305 | #ifdef CONFIG_COMPAT | |
306 | long lib_ring_buffer_compat_ioctl(struct file *filp, unsigned int cmd, | |
d83004aa | 307 | unsigned long arg, struct lib_ring_buffer *buf) |
f3bc08c5 | 308 | { |
f3bc08c5 | 309 | struct channel *chan = buf->backend.chan; |
5a8fd222 | 310 | const struct lib_ring_buffer_config *config = &chan->backend.config; |
254ec7bc MD |
311 | |
312 | if (lib_ring_buffer_channel_is_disabled(chan)) | |
313 | return -EIO; | |
f3bc08c5 MD |
314 | |
315 | switch (cmd) { | |
216f7feb | 316 | case RING_BUFFER_COMPAT_SNAPSHOT: |
f3bc08c5 MD |
317 | return lib_ring_buffer_snapshot(buf, &buf->cons_snapshot, |
318 | &buf->prod_snapshot); | |
4dce5a48 JG |
319 | case RING_BUFFER_COMPAT_SNAPSHOT_SAMPLE_POSITIONS: |
320 | return lib_ring_buffer_snapshot_sample_positions(buf, | |
321 | &buf->cons_snapshot, &buf->prod_snapshot); | |
216f7feb | 322 | case RING_BUFFER_COMPAT_SNAPSHOT_GET_CONSUMED: |
f3bc08c5 | 323 | return compat_put_ulong(buf->cons_snapshot, arg); |
216f7feb | 324 | case RING_BUFFER_COMPAT_SNAPSHOT_GET_PRODUCED: |
f3bc08c5 | 325 | return compat_put_ulong(buf->prod_snapshot, arg); |
216f7feb | 326 | case RING_BUFFER_COMPAT_GET_SUBBUF: |
f3bc08c5 MD |
327 | { |
328 | __u32 uconsume; | |
329 | unsigned long consume; | |
330 | long ret; | |
331 | ||
332 | ret = get_user(uconsume, (__u32 __user *) arg); | |
333 | if (ret) | |
334 | return ret; /* will return -EFAULT */ | |
335 | consume = buf->cons_snapshot; | |
336 | consume &= ~0xFFFFFFFFL; | |
337 | consume |= uconsume; | |
338 | ret = lib_ring_buffer_get_subbuf(buf, consume); | |
339 | if (!ret) { | |
340 | /* Set file position to zero at each successful "get" */ | |
341 | filp->f_pos = 0; | |
342 | } | |
343 | return ret; | |
344 | } | |
216f7feb | 345 | case RING_BUFFER_COMPAT_PUT_SUBBUF: |
f3bc08c5 MD |
346 | lib_ring_buffer_put_subbuf(buf); |
347 | return 0; | |
348 | ||
216f7feb | 349 | case RING_BUFFER_COMPAT_GET_NEXT_SUBBUF: |
f3bc08c5 MD |
350 | { |
351 | long ret; | |
352 | ||
353 | ret = lib_ring_buffer_get_next_subbuf(buf); | |
354 | if (!ret) { | |
355 | /* Set file position to zero at each successful "get" */ | |
356 | filp->f_pos = 0; | |
357 | } | |
358 | return ret; | |
359 | } | |
216f7feb | 360 | case RING_BUFFER_COMPAT_PUT_NEXT_SUBBUF: |
f3bc08c5 MD |
361 | lib_ring_buffer_put_next_subbuf(buf); |
362 | return 0; | |
216f7feb | 363 | case RING_BUFFER_COMPAT_GET_SUBBUF_SIZE: |
f3bc08c5 MD |
364 | { |
365 | unsigned long data_size; | |
366 | ||
367 | data_size = lib_ring_buffer_get_read_data_size(config, buf); | |
368 | if (data_size > UINT_MAX) | |
369 | return -EFBIG; | |
4343ec8e | 370 | return compat_put_ulong(data_size, arg); |
f3bc08c5 | 371 | } |
216f7feb | 372 | case RING_BUFFER_COMPAT_GET_PADDED_SUBBUF_SIZE: |
f3bc08c5 MD |
373 | { |
374 | unsigned long size; | |
375 | ||
376 | size = lib_ring_buffer_get_read_data_size(config, buf); | |
377 | size = PAGE_ALIGN(size); | |
378 | if (size > UINT_MAX) | |
379 | return -EFBIG; | |
4343ec8e | 380 | return compat_put_ulong(size, arg); |
f3bc08c5 | 381 | } |
216f7feb | 382 | case RING_BUFFER_COMPAT_GET_MAX_SUBBUF_SIZE: |
f3bc08c5 MD |
383 | if (chan->backend.subbuf_size > UINT_MAX) |
384 | return -EFBIG; | |
4343ec8e | 385 | return compat_put_ulong(chan->backend.subbuf_size, arg); |
216f7feb | 386 | case RING_BUFFER_COMPAT_GET_MMAP_LEN: |
f3bc08c5 MD |
387 | { |
388 | unsigned long mmap_buf_len; | |
389 | ||
390 | if (config->output != RING_BUFFER_MMAP) | |
391 | return -EINVAL; | |
392 | mmap_buf_len = chan->backend.buf_size; | |
393 | if (chan->backend.extra_reader_sb) | |
394 | mmap_buf_len += chan->backend.subbuf_size; | |
395 | if (mmap_buf_len > UINT_MAX) | |
396 | return -EFBIG; | |
4343ec8e | 397 | return compat_put_ulong(mmap_buf_len, arg); |
f3bc08c5 | 398 | } |
216f7feb | 399 | case RING_BUFFER_COMPAT_GET_MMAP_READ_OFFSET: |
f3bc08c5 MD |
400 | { |
401 | unsigned long sb_bindex, read_offset; | |
402 | ||
403 | if (config->output != RING_BUFFER_MMAP) | |
404 | return -EINVAL; | |
405 | sb_bindex = subbuffer_id_get_index(config, | |
406 | buf->backend.buf_rsb.id); | |
407 | read_offset = buf->backend.array[sb_bindex]->mmap_offset; | |
408 | if (read_offset > UINT_MAX) | |
409 | return -EINVAL; | |
4343ec8e | 410 | return compat_put_ulong(read_offset, arg); |
f3bc08c5 | 411 | } |
216f7feb | 412 | case RING_BUFFER_COMPAT_FLUSH: |
5e391252 | 413 | lib_ring_buffer_switch_remote(buf); |
5c055266 | 414 | return 0; |
c6f05468 MD |
415 | case RING_BUFFER_COMPAT_FLUSH_EMPTY: |
416 | lib_ring_buffer_switch_remote_empty(buf); | |
417 | return 0; | |
c245d0d3 MD |
418 | case RING_BUFFER_COMPAT_CLEAR: |
419 | lib_ring_buffer_clear(buf); | |
420 | return 0; | |
f3bc08c5 MD |
421 | default: |
422 | return -ENOIOCTLCMD; | |
423 | } | |
424 | } | |
d83004aa JD |
425 | EXPORT_SYMBOL_GPL(lib_ring_buffer_compat_ioctl); |
426 | ||
427 | static | |
428 | long vfs_lib_ring_buffer_compat_ioctl(struct file *filp, unsigned int cmd, | |
429 | unsigned long arg) | |
430 | { | |
431 | struct lib_ring_buffer *buf = filp->private_data; | |
432 | ||
433 | return lib_ring_buffer_compat_ioctl(filp, cmd, arg, buf); | |
434 | } | |
f3bc08c5 MD |
435 | #endif |
436 | ||
437 | const struct file_operations lib_ring_buffer_file_operations = { | |
a33c9927 | 438 | .owner = THIS_MODULE, |
d83004aa JD |
439 | .open = vfs_lib_ring_buffer_open, |
440 | .release = vfs_lib_ring_buffer_release, | |
441 | .poll = vfs_lib_ring_buffer_poll, | |
442 | .splice_read = vfs_lib_ring_buffer_splice_read, | |
443 | .mmap = vfs_lib_ring_buffer_mmap, | |
444 | .unlocked_ioctl = vfs_lib_ring_buffer_ioctl, | |
445 | .llseek = vfs_lib_ring_buffer_no_llseek, | |
f3bc08c5 | 446 | #ifdef CONFIG_COMPAT |
d83004aa | 447 | .compat_ioctl = vfs_lib_ring_buffer_compat_ioctl, |
f3bc08c5 MD |
448 | #endif |
449 | }; | |
450 | EXPORT_SYMBOL_GPL(lib_ring_buffer_file_operations); | |
451 | ||
452 | MODULE_LICENSE("GPL and additional rights"); | |
1c124020 MJ |
453 | MODULE_AUTHOR("Mathieu Desnoyers <mathieu.desnoyers@efficios.com>"); |
454 | MODULE_DESCRIPTION("LTTng ring buffer library"); | |
13ab8b0a MD |
455 | MODULE_VERSION(__stringify(LTTNG_MODULES_MAJOR_VERSION) "." |
456 | __stringify(LTTNG_MODULES_MINOR_VERSION) "." | |
457 | __stringify(LTTNG_MODULES_PATCHLEVEL_VERSION) | |
458 | LTTNG_MODULES_EXTRAVERSION); |