Commit | Line | Data |
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1d498196 MD |
1 | /* |
2 | * libringbuffer/shm.c | |
3 | * | |
e92f3e28 | 4 | * Copyright (C) 2005-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com> |
1d498196 | 5 | * |
e92f3e28 MD |
6 | * This library is free software; you can redistribute it and/or |
7 | * modify it under the terms of the GNU Lesser General Public | |
8 | * License as published by the Free Software Foundation; only | |
9 | * version 2.1 of the License. | |
10 | * | |
11 | * This library is distributed in the hope that it will be useful, | |
12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
14 | * Lesser General Public License for more details. | |
15 | * | |
16 | * You should have received a copy of the GNU Lesser General Public | |
17 | * License along with this library; if not, write to the Free Software | |
18 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA | |
1d498196 MD |
19 | */ |
20 | ||
21 | #include "shm.h" | |
22 | #include <unistd.h> | |
23 | #include <fcntl.h> | |
24 | #include <sys/mman.h> | |
25 | #include <sys/stat.h> /* For mode constants */ | |
26 | #include <fcntl.h> /* For O_* constants */ | |
27 | #include <assert.h> | |
8da6cd6d MD |
28 | #include <stdio.h> |
29 | #include <signal.h> | |
30 | #include <dirent.h> | |
4318ae1b | 31 | #include <lttng/align.h> |
35897f8b | 32 | #include <helper.h> |
96e80018 | 33 | #include <limits.h> |
3a81f31d MD |
34 | #include <helper.h> |
35 | ||
36 | /* | |
37 | * Ensure we have the required amount of space available by writing 0 | |
38 | * into the entire buffer. Not doing so can trigger SIGBUS when going | |
39 | * beyond the available shm space. | |
40 | */ | |
41 | static | |
42 | int zero_file(int fd, size_t len) | |
43 | { | |
44 | ssize_t retlen; | |
45 | size_t written = 0; | |
46 | char *zeropage; | |
47 | long pagelen; | |
48 | int ret; | |
49 | ||
50 | pagelen = sysconf(_SC_PAGESIZE); | |
51 | if (pagelen < 0) | |
52 | return (int) pagelen; | |
53 | zeropage = calloc(pagelen, 1); | |
54 | if (!zeropage) | |
55 | return -ENOMEM; | |
56 | ||
57 | while (len > written) { | |
58 | do { | |
59 | retlen = write(fd, zeropage, | |
60 | min_t(size_t, pagelen, len - written)); | |
61 | } while (retlen == -1UL && errno == EINTR); | |
62 | if (retlen < 0) { | |
63 | ret = (int) retlen; | |
64 | goto error; | |
65 | } | |
66 | written += retlen; | |
67 | } | |
68 | ret = 0; | |
69 | error: | |
70 | free(zeropage); | |
71 | return ret; | |
72 | } | |
1d498196 MD |
73 | |
74 | struct shm_object_table *shm_object_table_create(size_t max_nb_obj) | |
75 | { | |
76 | struct shm_object_table *table; | |
77 | ||
78 | table = zmalloc(sizeof(struct shm_object_table) + | |
79 | max_nb_obj * sizeof(table->objects[0])); | |
80 | table->size = max_nb_obj; | |
81 | return table; | |
82 | } | |
83 | ||
74d81a6c MD |
84 | static |
85 | struct shm_object *_shm_object_table_alloc_shm(struct shm_object_table *table, | |
1d498196 MD |
86 | size_t memory_map_size) |
87 | { | |
5a61337d | 88 | int shmfd, waitfd[2], ret, i, sigblocked = 0; |
1d498196 MD |
89 | struct shm_object *obj; |
90 | char *memory_map; | |
dda4784f | 91 | char tmp_name[NAME_MAX] = "/ust-shm-tmp-XXXXXX"; |
8da6cd6d | 92 | sigset_t all_sigs, orig_sigs; |
1d498196 MD |
93 | |
94 | if (table->allocated_len >= table->size) | |
95 | return NULL; | |
7a9c21bd | 96 | obj = &table->objects[table->allocated_len]; |
1d498196 MD |
97 | |
98 | /* wait_fd: create pipe */ | |
99 | ret = pipe(waitfd); | |
100 | if (ret < 0) { | |
101 | PERROR("pipe"); | |
102 | goto error_pipe; | |
103 | } | |
104 | for (i = 0; i < 2; i++) { | |
105 | ret = fcntl(waitfd[i], F_SETFD, FD_CLOEXEC); | |
106 | if (ret < 0) { | |
107 | PERROR("fcntl"); | |
108 | goto error_fcntl; | |
109 | } | |
110 | } | |
5d61a504 MD |
111 | /* The write end of the pipe needs to be non-blocking */ |
112 | ret = fcntl(waitfd[1], F_SETFL, O_NONBLOCK); | |
113 | if (ret < 0) { | |
114 | PERROR("fcntl"); | |
115 | goto error_fcntl; | |
116 | } | |
7a9c21bd | 117 | memcpy(obj->wait_fd, waitfd, sizeof(waitfd)); |
1d498196 MD |
118 | |
119 | /* shm_fd: create shm */ | |
120 | ||
8da6cd6d MD |
121 | /* |
122 | * Theoretically, we could leak a shm if the application crashes | |
123 | * between open and unlink. Disable signals on this thread for | |
124 | * increased safety against this scenario. | |
125 | */ | |
126 | sigfillset(&all_sigs); | |
127 | ret = pthread_sigmask(SIG_BLOCK, &all_sigs, &orig_sigs); | |
128 | if (ret == -1) { | |
129 | PERROR("pthread_sigmask"); | |
130 | goto error_pthread_sigmask; | |
131 | } | |
5a61337d | 132 | sigblocked = 1; |
8da6cd6d | 133 | |
1d498196 MD |
134 | /* |
135 | * Allocate shm, and immediately unlink its shm oject, keeping | |
136 | * only the file descriptor as a reference to the object. If it | |
137 | * already exists (caused by short race window during which the | |
138 | * global object exists in a concurrent shm_open), simply retry. | |
139 | * We specifically do _not_ use the / at the beginning of the | |
140 | * pathname so that some OS implementations can keep it local to | |
141 | * the process (POSIX leaves this implementation-defined). | |
142 | */ | |
143 | do { | |
8da6cd6d MD |
144 | /* |
145 | * Using mktemp filename with O_CREAT | O_EXCL open | |
146 | * flags. | |
147 | */ | |
af21f781 | 148 | (void) mktemp(tmp_name); |
8da6cd6d MD |
149 | if (tmp_name[0] == '\0') { |
150 | PERROR("mktemp"); | |
151 | goto error_shm_open; | |
a8803897 | 152 | } |
8da6cd6d | 153 | shmfd = shm_open(tmp_name, |
1d498196 | 154 | O_CREAT | O_EXCL | O_RDWR, 0700); |
8da6cd6d | 155 | } while (shmfd < 0 && (errno == EEXIST || errno == EACCES)); |
1d498196 MD |
156 | if (shmfd < 0) { |
157 | PERROR("shm_open"); | |
158 | goto error_shm_open; | |
159 | } | |
8da6cd6d | 160 | ret = shm_unlink(tmp_name); |
a8803897 MD |
161 | if (ret < 0 && errno != ENOENT) { |
162 | PERROR("shm_unlink"); | |
163 | goto error_shm_release; | |
164 | } | |
5a61337d | 165 | sigblocked = 0; |
8da6cd6d MD |
166 | ret = pthread_sigmask(SIG_SETMASK, &orig_sigs, NULL); |
167 | if (ret == -1) { | |
168 | PERROR("pthread_sigmask"); | |
5a61337d | 169 | goto error_sigmask_release; |
8da6cd6d | 170 | } |
3a81f31d MD |
171 | ret = zero_file(shmfd, memory_map_size); |
172 | if (ret) { | |
173 | PERROR("zero_file"); | |
174 | goto error_zero_file; | |
175 | } | |
1d498196 MD |
176 | ret = ftruncate(shmfd, memory_map_size); |
177 | if (ret) { | |
178 | PERROR("ftruncate"); | |
179 | goto error_ftruncate; | |
180 | } | |
181 | obj->shm_fd = shmfd; | |
182 | ||
183 | /* memory_map: mmap */ | |
184 | memory_map = mmap(NULL, memory_map_size, PROT_READ | PROT_WRITE, | |
185 | MAP_SHARED, shmfd, 0); | |
186 | if (memory_map == MAP_FAILED) { | |
187 | PERROR("mmap"); | |
188 | goto error_mmap; | |
189 | } | |
74d81a6c | 190 | obj->type = SHM_OBJECT_SHM; |
1d498196 MD |
191 | obj->memory_map = memory_map; |
192 | obj->memory_map_size = memory_map_size; | |
193 | obj->allocated_len = 0; | |
dc613eb9 | 194 | obj->index = table->allocated_len++; |
7a9c21bd | 195 | |
1d498196 MD |
196 | return obj; |
197 | ||
198 | error_mmap: | |
199 | error_ftruncate: | |
a8803897 | 200 | error_shm_release: |
3a81f31d | 201 | error_zero_file: |
5a61337d | 202 | error_sigmask_release: |
1d498196 MD |
203 | ret = close(shmfd); |
204 | if (ret) { | |
205 | PERROR("close"); | |
206 | assert(0); | |
207 | } | |
208 | error_shm_open: | |
5a61337d MD |
209 | if (sigblocked) { |
210 | ret = pthread_sigmask(SIG_SETMASK, &orig_sigs, NULL); | |
211 | if (ret == -1) { | |
212 | PERROR("pthread_sigmask"); | |
213 | } | |
214 | } | |
8da6cd6d | 215 | error_pthread_sigmask: |
1d498196 MD |
216 | error_fcntl: |
217 | for (i = 0; i < 2; i++) { | |
218 | ret = close(waitfd[i]); | |
219 | if (ret) { | |
220 | PERROR("close"); | |
221 | assert(0); | |
222 | } | |
223 | } | |
224 | error_pipe: | |
1d498196 | 225 | return NULL; |
1d498196 MD |
226 | } |
227 | ||
74d81a6c MD |
228 | static |
229 | struct shm_object *_shm_object_table_alloc_mem(struct shm_object_table *table, | |
230 | size_t memory_map_size) | |
231 | { | |
232 | struct shm_object *obj; | |
233 | void *memory_map; | |
ff0f5728 | 234 | int waitfd[2], i, ret; |
74d81a6c MD |
235 | |
236 | if (table->allocated_len >= table->size) | |
237 | return NULL; | |
238 | obj = &table->objects[table->allocated_len]; | |
239 | ||
240 | memory_map = zmalloc(memory_map_size); | |
241 | if (!memory_map) | |
242 | goto alloc_error; | |
243 | ||
ff0f5728 MD |
244 | /* wait_fd: create pipe */ |
245 | ret = pipe(waitfd); | |
246 | if (ret < 0) { | |
247 | PERROR("pipe"); | |
248 | goto error_pipe; | |
249 | } | |
250 | for (i = 0; i < 2; i++) { | |
251 | ret = fcntl(waitfd[i], F_SETFD, FD_CLOEXEC); | |
252 | if (ret < 0) { | |
253 | PERROR("fcntl"); | |
254 | goto error_fcntl; | |
255 | } | |
256 | } | |
257 | /* The write end of the pipe needs to be non-blocking */ | |
258 | ret = fcntl(waitfd[1], F_SETFL, O_NONBLOCK); | |
259 | if (ret < 0) { | |
260 | PERROR("fcntl"); | |
261 | goto error_fcntl; | |
262 | } | |
263 | memcpy(obj->wait_fd, waitfd, sizeof(waitfd)); | |
264 | ||
265 | /* no shm_fd */ | |
74d81a6c MD |
266 | obj->shm_fd = -1; |
267 | ||
268 | obj->type = SHM_OBJECT_MEM; | |
269 | obj->memory_map = memory_map; | |
270 | obj->memory_map_size = memory_map_size; | |
271 | obj->allocated_len = 0; | |
272 | obj->index = table->allocated_len++; | |
273 | ||
274 | return obj; | |
275 | ||
ff0f5728 MD |
276 | error_fcntl: |
277 | for (i = 0; i < 2; i++) { | |
278 | ret = close(waitfd[i]); | |
279 | if (ret) { | |
280 | PERROR("close"); | |
281 | assert(0); | |
282 | } | |
283 | } | |
284 | error_pipe: | |
285 | free(memory_map); | |
74d81a6c MD |
286 | alloc_error: |
287 | return NULL; | |
288 | } | |
289 | ||
290 | struct shm_object *shm_object_table_alloc(struct shm_object_table *table, | |
291 | size_t memory_map_size, | |
292 | enum shm_object_type type) | |
293 | { | |
294 | switch (type) { | |
295 | case SHM_OBJECT_SHM: | |
296 | return _shm_object_table_alloc_shm(table, memory_map_size); | |
297 | case SHM_OBJECT_MEM: | |
298 | return _shm_object_table_alloc_mem(table, memory_map_size); | |
299 | default: | |
300 | assert(0); | |
301 | } | |
302 | return NULL; | |
303 | } | |
304 | ||
305 | struct shm_object *shm_object_table_append_shm(struct shm_object_table *table, | |
306 | int shm_fd, int wakeup_fd, uint32_t stream_nr, | |
307 | size_t memory_map_size) | |
193183fb MD |
308 | { |
309 | struct shm_object *obj; | |
310 | char *memory_map; | |
74d81a6c | 311 | int ret; |
193183fb MD |
312 | |
313 | if (table->allocated_len >= table->size) | |
314 | return NULL; | |
74d81a6c MD |
315 | /* streams _must_ be received in sequential order, else fail. */ |
316 | if (stream_nr + 1 != table->allocated_len) | |
317 | return NULL; | |
318 | ||
193183fb MD |
319 | obj = &table->objects[table->allocated_len]; |
320 | ||
74d81a6c MD |
321 | /* wait_fd: set write end of the pipe. */ |
322 | obj->wait_fd[0] = -1; /* read end is unset */ | |
323 | obj->wait_fd[1] = wakeup_fd; | |
193183fb MD |
324 | obj->shm_fd = shm_fd; |
325 | ||
74d81a6c MD |
326 | ret = fcntl(obj->wait_fd[1], F_SETFD, FD_CLOEXEC); |
327 | if (ret < 0) { | |
328 | PERROR("fcntl"); | |
329 | goto error_fcntl; | |
330 | } | |
331 | /* The write end of the pipe needs to be non-blocking */ | |
332 | ret = fcntl(obj->wait_fd[1], F_SETFL, O_NONBLOCK); | |
333 | if (ret < 0) { | |
334 | PERROR("fcntl"); | |
335 | goto error_fcntl; | |
336 | } | |
337 | ||
193183fb MD |
338 | /* memory_map: mmap */ |
339 | memory_map = mmap(NULL, memory_map_size, PROT_READ | PROT_WRITE, | |
340 | MAP_SHARED, shm_fd, 0); | |
341 | if (memory_map == MAP_FAILED) { | |
342 | PERROR("mmap"); | |
343 | goto error_mmap; | |
344 | } | |
74d81a6c | 345 | obj->type = SHM_OBJECT_SHM; |
193183fb MD |
346 | obj->memory_map = memory_map; |
347 | obj->memory_map_size = memory_map_size; | |
348 | obj->allocated_len = memory_map_size; | |
349 | obj->index = table->allocated_len++; | |
350 | ||
351 | return obj; | |
352 | ||
74d81a6c | 353 | error_fcntl: |
193183fb MD |
354 | error_mmap: |
355 | return NULL; | |
356 | } | |
357 | ||
74d81a6c MD |
358 | /* |
359 | * Passing ownership of mem to object. | |
360 | */ | |
361 | struct shm_object *shm_object_table_append_mem(struct shm_object_table *table, | |
ff0f5728 | 362 | void *mem, size_t memory_map_size, int wakeup_fd) |
74d81a6c MD |
363 | { |
364 | struct shm_object *obj; | |
ff0f5728 | 365 | int ret; |
74d81a6c MD |
366 | |
367 | if (table->allocated_len >= table->size) | |
368 | return NULL; | |
369 | obj = &table->objects[table->allocated_len]; | |
370 | ||
ff0f5728 MD |
371 | obj->wait_fd[0] = -1; /* read end is unset */ |
372 | obj->wait_fd[1] = wakeup_fd; | |
74d81a6c MD |
373 | obj->shm_fd = -1; |
374 | ||
ff0f5728 MD |
375 | ret = fcntl(obj->wait_fd[1], F_SETFD, FD_CLOEXEC); |
376 | if (ret < 0) { | |
377 | PERROR("fcntl"); | |
378 | goto error_fcntl; | |
379 | } | |
380 | /* The write end of the pipe needs to be non-blocking */ | |
381 | ret = fcntl(obj->wait_fd[1], F_SETFL, O_NONBLOCK); | |
382 | if (ret < 0) { | |
383 | PERROR("fcntl"); | |
384 | goto error_fcntl; | |
385 | } | |
386 | ||
74d81a6c MD |
387 | obj->type = SHM_OBJECT_MEM; |
388 | obj->memory_map = mem; | |
389 | obj->memory_map_size = memory_map_size; | |
390 | obj->allocated_len = memory_map_size; | |
391 | obj->index = table->allocated_len++; | |
392 | ||
393 | return obj; | |
ff0f5728 MD |
394 | |
395 | error_fcntl: | |
396 | return NULL; | |
74d81a6c MD |
397 | } |
398 | ||
1d498196 MD |
399 | static |
400 | void shmp_object_destroy(struct shm_object *obj) | |
401 | { | |
74d81a6c MD |
402 | switch (obj->type) { |
403 | case SHM_OBJECT_SHM: | |
404 | { | |
405 | int ret, i; | |
1d498196 | 406 | |
7a784989 MD |
407 | ret = munmap(obj->memory_map, obj->memory_map_size); |
408 | if (ret) { | |
409 | PERROR("umnmap"); | |
410 | assert(0); | |
411 | } | |
ef9ff354 MD |
412 | ret = close(obj->shm_fd); |
413 | if (ret) { | |
414 | PERROR("close"); | |
415 | assert(0); | |
416 | } | |
74d81a6c MD |
417 | for (i = 0; i < 2; i++) { |
418 | if (obj->wait_fd[i] < 0) | |
419 | continue; | |
420 | ret = close(obj->wait_fd[i]); | |
421 | if (ret) { | |
422 | PERROR("close"); | |
423 | assert(0); | |
424 | } | |
1d498196 | 425 | } |
74d81a6c MD |
426 | break; |
427 | } | |
428 | case SHM_OBJECT_MEM: | |
ff0f5728 MD |
429 | { |
430 | int ret, i; | |
431 | ||
432 | for (i = 0; i < 2; i++) { | |
433 | if (obj->wait_fd[i] < 0) | |
434 | continue; | |
435 | ret = close(obj->wait_fd[i]); | |
436 | if (ret) { | |
437 | PERROR("close"); | |
438 | assert(0); | |
439 | } | |
440 | } | |
74d81a6c MD |
441 | free(obj->memory_map); |
442 | break; | |
ff0f5728 | 443 | } |
74d81a6c MD |
444 | default: |
445 | assert(0); | |
1d498196 MD |
446 | } |
447 | } | |
448 | ||
449 | void shm_object_table_destroy(struct shm_object_table *table) | |
450 | { | |
451 | int i; | |
452 | ||
453 | for (i = 0; i < table->allocated_len; i++) | |
454 | shmp_object_destroy(&table->objects[i]); | |
455 | free(table); | |
456 | } | |
457 | ||
458 | /* | |
459 | * zalloc_shm - allocate memory within a shm object. | |
460 | * | |
461 | * Shared memory is already zeroed by shmget. | |
462 | * *NOT* multithread-safe (should be protected by mutex). | |
463 | * Returns a -1, -1 tuple on error. | |
464 | */ | |
465 | struct shm_ref zalloc_shm(struct shm_object *obj, size_t len) | |
466 | { | |
467 | struct shm_ref ref; | |
468 | struct shm_ref shm_ref_error = { -1, -1 }; | |
469 | ||
470 | if (obj->memory_map_size - obj->allocated_len < len) | |
471 | return shm_ref_error; | |
472 | ref.index = obj->index; | |
473 | ref.offset = obj->allocated_len; | |
474 | obj->allocated_len += len; | |
475 | return ref; | |
476 | } | |
477 | ||
478 | void align_shm(struct shm_object *obj, size_t align) | |
479 | { | |
480 | size_t offset_len = offset_align(obj->allocated_len, align); | |
481 | obj->allocated_len += offset_len; | |
482 | } |