700d350d |
1 | /* LTTng user-space "fast" library |
2 | * |
3 | * This daemon is spawned by each traced thread (to share the mmap). |
4 | * |
5 | * Its job is to dump periodically this buffer to disk (when it receives a |
6 | * SIGUSR1 from its parent). |
7 | * |
8 | * It uses the control information in the shared memory area (producer/consumer |
9 | * count). |
10 | * |
11 | * When the parent thread dies (yes, those thing may happen) ;) , this daemon |
12 | * will flush the last buffer and write it to disk. |
13 | * |
14 | * Supplement note for streaming : the daemon is responsible for flushing |
15 | * periodically the buffer if it is streaming data. |
16 | * |
b09f3215 |
17 | * |
700d350d |
18 | * Notes : |
19 | * shm memory is typically limited to 4096 units (system wide limit SHMMNI in |
20 | * /proc/sys/kernel/shmmni). As it requires computation time upon creation, we |
21 | * do not use it : we will use a shared mmap() instead which is passed through |
22 | * the fork(). |
23 | * MAP_SHARED mmap segment. Updated when msync or munmap are called. |
24 | * MAP_ANONYMOUS. |
25 | * Memory mapped by mmap() is preserved across fork(2), with the same |
26 | * attributes. |
27 | * |
28 | * Eventually, there will be two mode : |
29 | * * Slow thread spawn : a fork() is done for each new thread. If the process |
30 | * dies, the data is not lost. |
31 | * * Fast thread spawn : a pthread_create() is done by the application for each |
32 | * new thread. |
a85b8f41 |
33 | * |
34 | * We use a timer to check periodically if the parent died. I think it is less |
35 | * intrusive than a ptrace() on the parent, which would get every signal. The |
36 | * side effect of this is that we won't be notified if the parent does an |
37 | * exec(). In this case, we will just sit there until the parent exits. |
38 | * |
39 | * |
b09f3215 |
40 | * Copyright 2006 Mathieu Desnoyers |
41 | * |
42 | */ |
43 | |
8a9103df |
44 | #define inline inline __attribute__((always_inline)) |
45 | |
32f2b04a |
46 | #define _GNU_SOURCE |
8b30e7bc |
47 | #define LTT_TRACE |
976db1b3 |
48 | #define LTT_TRACE_FAST |
b09f3215 |
49 | #include <unistd.h> |
50 | #include <stdlib.h> |
51 | #include <stdio.h> |
52 | #include <signal.h> |
53 | #include <syscall.h> |
54 | #include <features.h> |
55 | #include <pthread.h> |
56 | #include <malloc.h> |
57 | #include <string.h> |
700d350d |
58 | #include <signal.h> |
77b31f39 |
59 | #include <fcntl.h> |
60 | #include <stdlib.h> |
4359c2bb |
61 | #include <errno.h> |
77b31f39 |
62 | #include <sys/param.h> |
47d7d576 |
63 | #include <sys/time.h> |
4359c2bb |
64 | #include <sys/types.h> |
65 | #include <sys/wait.h> |
66 | #include <sys/stat.h> |
67 | #include <sys/mman.h> |
5ecaa1ab |
68 | #include <unistd.h> |
69 | #include <sys/syscall.h> |
77b31f39 |
70 | |
976db1b3 |
71 | #include <ltt/ltt-usertrace.h> |
b09f3215 |
72 | |
5ecaa1ab |
73 | #define gettid() syscall(__NR_gettid) |
4359c2bb |
74 | |
8a9103df |
75 | #ifdef LTT_SHOW_DEBUG |
fcbe1ea8 |
76 | #define dbg_printf(...) printf(__VA_ARGS__) |
8a9103df |
77 | #else |
78 | #define dbg_printf(...) |
79 | #endif //LTT_SHOW_DEBUG |
80 | |
81 | |
32f2b04a |
82 | enum force_switch_mode { FORCE_ACTIVE, FORCE_FLUSH }; |
b09f3215 |
83 | |
e8efa18d |
84 | /* Writer (the traced application) */ |
b09f3215 |
85 | |
e8efa18d |
86 | __thread struct ltt_trace_info *thread_trace_info = NULL; |
700d350d |
87 | |
e8efa18d |
88 | void ltt_usertrace_fast_buffer_switch(void) |
89 | { |
a85b8f41 |
90 | struct ltt_trace_info *tmp = thread_trace_info; |
91 | if(tmp) |
92 | kill(tmp->daemon_id, SIGUSR1); |
e8efa18d |
93 | } |
700d350d |
94 | |
77b31f39 |
95 | /* The cleanup should never be called from a signal handler */ |
e8efa18d |
96 | static void ltt_usertrace_fast_cleanup(void *arg) |
b09f3215 |
97 | { |
a85b8f41 |
98 | struct ltt_trace_info *tmp = thread_trace_info; |
99 | if(tmp) { |
100 | thread_trace_info = NULL; |
101 | kill(tmp->daemon_id, SIGUSR2); |
102 | munmap(tmp, sizeof(*tmp)); |
103 | } |
700d350d |
104 | } |
b09f3215 |
105 | |
e8efa18d |
106 | /* Reader (the disk dumper daemon) */ |
700d350d |
107 | |
a85b8f41 |
108 | static pid_t traced_pid = 0; |
4c992ad5 |
109 | static pid_t traced_tid = 0; |
e8efa18d |
110 | static int parent_exited = 0; |
c095a20d |
111 | static int fd_process = -1; |
112 | static char outfile_name[PATH_MAX]; |
113 | static char identifier_name[PATH_MAX]; |
700d350d |
114 | |
e8efa18d |
115 | /* signal handling */ |
116 | static void handler_sigusr1(int signo) |
700d350d |
117 | { |
8a9103df |
118 | dbg_printf("LTT Signal %d received : parent buffer switch.\n", signo); |
e8efa18d |
119 | } |
120 | |
121 | static void handler_sigusr2(int signo) |
122 | { |
8a9103df |
123 | dbg_printf("LTT Signal %d received : parent exited.\n", signo); |
e8efa18d |
124 | parent_exited = 1; |
125 | } |
126 | |
127 | static void handler_sigalarm(int signo) |
128 | { |
8a9103df |
129 | dbg_printf("LTT Signal %d received\n", signo); |
e8efa18d |
130 | |
a85b8f41 |
131 | if(getppid() != traced_pid) { |
e8efa18d |
132 | /* Parent died */ |
8a9103df |
133 | dbg_printf("LTT Parent %lu died, cleaning up\n", traced_pid); |
a85b8f41 |
134 | traced_pid = 0; |
e8efa18d |
135 | } |
136 | alarm(3); |
b09f3215 |
137 | } |
138 | |
47d7d576 |
139 | /* Do a buffer switch. Don't switch if buffer is completely empty */ |
32f2b04a |
140 | static void flush_buffer(struct ltt_buf *ltt_buf, enum force_switch_mode mode) |
47d7d576 |
141 | { |
32f2b04a |
142 | uint64_t tsc; |
143 | int offset_begin, offset_end, offset_old; |
144 | int reserve_commit_diff; |
145 | int consumed_old, consumed_new; |
146 | int commit_count, reserve_count; |
147 | int end_switch_old; |
47d7d576 |
148 | |
32f2b04a |
149 | do { |
150 | offset_old = atomic_read(<t_buf->offset); |
151 | offset_begin = offset_old; |
152 | end_switch_old = 0; |
153 | tsc = ltt_get_timestamp(); |
154 | if(tsc == 0) { |
155 | /* Error in getting the timestamp : should not happen : it would |
156 | * mean we are called from an NMI during a write seqlock on xtime. */ |
157 | return; |
158 | } |
159 | |
160 | if(SUBBUF_OFFSET(offset_begin, ltt_buf) != 0) { |
161 | offset_begin = SUBBUF_ALIGN(offset_begin, ltt_buf); |
162 | end_switch_old = 1; |
163 | } else { |
164 | /* we do not have to switch : buffer is empty */ |
165 | return; |
166 | } |
167 | if(mode == FORCE_ACTIVE) |
168 | offset_begin += ltt_subbuf_header_len(ltt_buf); |
169 | /* Always begin_switch in FORCE_ACTIVE mode */ |
170 | |
171 | /* Test new buffer integrity */ |
172 | reserve_commit_diff = |
173 | atomic_read( |
174 | <t_buf->reserve_count[SUBBUF_INDEX(offset_begin, ltt_buf)]) |
175 | - atomic_read( |
176 | <t_buf->commit_count[SUBBUF_INDEX(offset_begin, ltt_buf)]); |
177 | if(reserve_commit_diff == 0) { |
178 | /* Next buffer not corrupted. */ |
179 | if(mode == FORCE_ACTIVE |
180 | && (offset_begin-atomic_read(<t_buf->consumed)) |
181 | >= ltt_buf->alloc_size) { |
182 | /* We do not overwrite non consumed buffers and we are full : ignore |
183 | switch while tracing is active. */ |
184 | return; |
185 | } |
186 | } else { |
187 | /* Next subbuffer corrupted. Force pushing reader even in normal mode */ |
188 | } |
189 | |
190 | offset_end = offset_begin; |
191 | } while(atomic_cmpxchg(<t_buf->offset, offset_old, offset_end) |
192 | != offset_old); |
193 | |
194 | |
195 | if(mode == FORCE_ACTIVE) { |
196 | /* Push the reader if necessary */ |
197 | do { |
198 | consumed_old = atomic_read(<t_buf->consumed); |
199 | /* If buffer is in overwrite mode, push the reader consumed count if |
200 | the write position has reached it and we are not at the first |
201 | iteration (don't push the reader farther than the writer). |
202 | This operation can be done concurrently by many writers in the |
203 | same buffer, the writer being at the fartest write position sub-buffer |
204 | index in the buffer being the one which will win this loop. */ |
205 | /* If the buffer is not in overwrite mode, pushing the reader only |
206 | happen if a sub-buffer is corrupted */ |
680b9daa |
207 | if((SUBBUF_TRUNC(offset_end-1, ltt_buf) |
32f2b04a |
208 | - SUBBUF_TRUNC(consumed_old, ltt_buf)) |
209 | >= ltt_buf->alloc_size) |
210 | consumed_new = SUBBUF_ALIGN(consumed_old, ltt_buf); |
211 | else { |
212 | consumed_new = consumed_old; |
213 | break; |
214 | } |
215 | } while(atomic_cmpxchg(<t_buf->consumed, consumed_old, consumed_new) |
216 | != consumed_old); |
217 | |
218 | if(consumed_old != consumed_new) { |
219 | /* Reader pushed : we are the winner of the push, we can therefore |
220 | reequilibrate reserve and commit. Atomic increment of the commit |
221 | count permits other writers to play around with this variable |
222 | before us. We keep track of corrupted_subbuffers even in overwrite |
223 | mode : |
224 | we never want to write over a non completely committed sub-buffer : |
225 | possible causes : the buffer size is too low compared to the unordered |
226 | data input, or there is a writer who died between the reserve and the |
227 | commit. */ |
228 | if(reserve_commit_diff) { |
229 | /* We have to alter the sub-buffer commit count : a sub-buffer is |
230 | corrupted */ |
231 | atomic_add(reserve_commit_diff, |
232 | <t_buf->commit_count[SUBBUF_INDEX(offset_begin, ltt_buf)]); |
233 | atomic_inc(<t_buf->corrupted_subbuffers); |
234 | } |
235 | } |
236 | } |
237 | |
238 | /* Always switch */ |
239 | |
240 | if(end_switch_old) { |
241 | /* old subbuffer */ |
242 | /* Concurrency safe because we are the last and only thread to alter this |
243 | sub-buffer. As long as it is not delivered and read, no other thread can |
244 | alter the offset, alter the reserve_count or call the |
245 | client_buffer_end_callback on this sub-buffer. |
246 | The only remaining threads could be the ones with pending commits. They |
247 | will have to do the deliver themself. |
248 | Not concurrency safe in overwrite mode. We detect corrupted subbuffers with |
249 | commit and reserve counts. We keep a corrupted sub-buffers count and push |
250 | the readers across these sub-buffers. |
251 | Not concurrency safe if a writer is stalled in a subbuffer and |
252 | another writer switches in, finding out it's corrupted. The result will be |
253 | than the old (uncommited) subbuffer will be declared corrupted, and that |
254 | the new subbuffer will be declared corrupted too because of the commit |
255 | count adjustment. |
256 | Offset old should never be 0. */ |
257 | ltt_buffer_end_callback(ltt_buf, tsc, offset_old, |
258 | SUBBUF_INDEX((offset_old), ltt_buf)); |
259 | /* Setting this reserve_count will allow the sub-buffer to be delivered by |
260 | the last committer. */ |
261 | reserve_count = atomic_add_return((SUBBUF_OFFSET((offset_old-1), |
262 | ltt_buf) + 1), |
263 | <t_buf->reserve_count[SUBBUF_INDEX((offset_old), |
264 | ltt_buf)]); |
265 | if(reserve_count == atomic_read( |
266 | <t_buf->commit_count[SUBBUF_INDEX((offset_old), ltt_buf)])) { |
267 | ltt_deliver_callback(ltt_buf, SUBBUF_INDEX((offset_old), ltt_buf), NULL); |
268 | } |
269 | } |
270 | |
271 | if(mode == FORCE_ACTIVE) { |
272 | /* New sub-buffer */ |
273 | /* This code can be executed unordered : writers may already have written |
274 | to the sub-buffer before this code gets executed, caution. */ |
275 | /* The commit makes sure that this code is executed before the deliver |
276 | of this sub-buffer */ |
277 | ltt_buffer_begin_callback(ltt_buf, tsc, SUBBUF_INDEX(offset_begin, ltt_buf)); |
278 | commit_count = atomic_add_return(ltt_subbuf_header_len(ltt_buf), |
279 | <t_buf->commit_count[SUBBUF_INDEX(offset_begin, ltt_buf)]); |
280 | /* Check if the written buffer has to be delivered */ |
281 | if(commit_count == atomic_read( |
282 | <t_buf->reserve_count[SUBBUF_INDEX(offset_begin, ltt_buf)])) { |
283 | ltt_deliver_callback(ltt_buf, SUBBUF_INDEX(offset_begin, ltt_buf), NULL); |
284 | } |
285 | } |
47d7d576 |
286 | |
287 | } |
288 | |
c095a20d |
289 | |
290 | static int open_output_files(void) |
291 | { |
292 | int ret; |
293 | int fd; |
294 | /* Open output files */ |
295 | umask(00000); |
296 | ret = mkdir(LTT_USERTRACE_ROOT, 0777); |
297 | if(ret < 0 && errno != EEXIST) { |
298 | perror("LTT Error in creating output (mkdir)"); |
299 | exit(-1); |
300 | } |
301 | ret = chdir(LTT_USERTRACE_ROOT); |
302 | if(ret < 0) { |
303 | perror("LTT Error in creating output (chdir)"); |
304 | exit(-1); |
305 | } |
306 | snprintf(identifier_name, PATH_MAX-1, "%lu.%lu.%llu", |
307 | traced_tid, traced_pid, get_cycles()); |
308 | snprintf(outfile_name, PATH_MAX-1, "process-%s", identifier_name); |
309 | |
310 | #ifndef LTT_NULL_OUTPUT_TEST |
311 | fd = creat(outfile_name, 0644); |
312 | #else |
313 | /* NULL test */ |
314 | ret = symlink("/dev/null", outfile_name); |
315 | if(ret < 0) { |
316 | perror("error in symlink"); |
317 | exit(-1); |
318 | } |
319 | fd = open(outfile_name, O_WRONLY); |
320 | if(fd_process < 0) { |
321 | perror("Error in open"); |
322 | exit(-1); |
323 | } |
324 | #endif //LTT_NULL_OUTPUT_TEST |
325 | return fd; |
326 | } |
327 | |
47d7d576 |
328 | static inline int ltt_buffer_get(struct ltt_buf *ltt_buf, |
329 | unsigned int *offset) |
330 | { |
331 | unsigned int consumed_old, consumed_idx; |
332 | consumed_old = atomic_read(<t_buf->consumed); |
333 | consumed_idx = SUBBUF_INDEX(consumed_old, ltt_buf); |
334 | |
335 | if(atomic_read(<t_buf->commit_count[consumed_idx]) |
336 | != atomic_read(<t_buf->reserve_count[consumed_idx])) { |
337 | return -EAGAIN; |
338 | } |
339 | if((SUBBUF_TRUNC(atomic_read(<t_buf->offset), ltt_buf) |
340 | -SUBBUF_TRUNC(consumed_old, ltt_buf)) == 0) { |
341 | return -EAGAIN; |
342 | } |
343 | |
344 | *offset = consumed_old; |
345 | |
346 | return 0; |
347 | } |
348 | |
349 | static inline int ltt_buffer_put(struct ltt_buf *ltt_buf, |
350 | unsigned int offset) |
351 | { |
352 | unsigned int consumed_old, consumed_new; |
353 | int ret; |
354 | |
355 | consumed_old = offset; |
356 | consumed_new = SUBBUF_ALIGN(consumed_old, ltt_buf); |
357 | if(atomic_cmpxchg(<t_buf->consumed, consumed_old, consumed_new) |
358 | != consumed_old) { |
359 | /* We have been pushed by the writer : the last buffer read _is_ |
360 | * corrupted! |
361 | * It can also happen if this is a buffer we never got. */ |
362 | return -EIO; |
363 | } else { |
e0cd021d |
364 | if(traced_pid == 0 || parent_exited) return 0; |
365 | |
85b94320 |
366 | ret = sem_post(<t_buf->writer_sem); |
367 | if(ret < 0) { |
368 | printf("error in sem_post"); |
47d7d576 |
369 | } |
370 | } |
68440b1d |
371 | return ret; |
47d7d576 |
372 | } |
373 | |
47d7d576 |
374 | static int read_subbuffer(struct ltt_buf *ltt_buf, int fd) |
375 | { |
32f2b04a |
376 | unsigned int consumed_old; |
47d7d576 |
377 | int err; |
8a9103df |
378 | dbg_printf("LTT read buffer\n"); |
47d7d576 |
379 | |
380 | |
32f2b04a |
381 | err = ltt_buffer_get(ltt_buf, &consumed_old); |
5ffa9d14 |
382 | if(err != 0) { |
8a9103df |
383 | if(err != -EAGAIN) dbg_printf("LTT Reserving sub buffer failed\n"); |
47d7d576 |
384 | goto get_error; |
385 | } |
c095a20d |
386 | if(fd_process == -1) { |
387 | fd_process = fd = open_output_files(); |
388 | } |
47d7d576 |
389 | |
390 | err = TEMP_FAILURE_RETRY(write(fd, |
391 | ltt_buf->start |
392 | + (consumed_old & ((ltt_buf->alloc_size)-1)), |
393 | ltt_buf->subbuf_size)); |
394 | |
395 | if(err < 0) { |
396 | perror("Error in writing to file"); |
397 | goto write_error; |
398 | } |
399 | #if 0 |
400 | err = fsync(pair->trace); |
401 | if(err < 0) { |
402 | ret = errno; |
403 | perror("Error in writing to file"); |
404 | goto write_error; |
405 | } |
406 | #endif //0 |
407 | write_error: |
32f2b04a |
408 | err = ltt_buffer_put(ltt_buf, consumed_old); |
47d7d576 |
409 | |
410 | if(err != 0) { |
411 | if(err == -EIO) { |
8a9103df |
412 | dbg_printf("Reader has been pushed by the writer, last subbuffer corrupted.\n"); |
47d7d576 |
413 | /* FIXME : we may delete the last written buffer if we wish. */ |
414 | } |
415 | goto get_error; |
416 | } |
417 | |
418 | get_error: |
419 | return err; |
420 | } |
e8efa18d |
421 | |
a85b8f41 |
422 | /* This function is called by ltt_rw_init which has signals blocked */ |
700d350d |
423 | static void ltt_usertrace_fast_daemon(struct ltt_trace_info *shared_trace_info, |
4c992ad5 |
424 | sigset_t oldset, pid_t l_traced_pid, pthread_t l_traced_tid) |
700d350d |
425 | { |
426 | struct sigaction act; |
427 | int ret; |
77b31f39 |
428 | |
a85b8f41 |
429 | traced_pid = l_traced_pid; |
4c992ad5 |
430 | traced_tid = l_traced_tid; |
e8efa18d |
431 | |
8a9103df |
432 | dbg_printf("LTT ltt_usertrace_fast_daemon : init is %d, pid is %lu, traced_pid is %lu, traced_tid is %lu\n", |
4c992ad5 |
433 | shared_trace_info->init, getpid(), traced_pid, traced_tid); |
700d350d |
434 | |
e8efa18d |
435 | act.sa_handler = handler_sigusr1; |
700d350d |
436 | act.sa_flags = 0; |
437 | sigemptyset(&(act.sa_mask)); |
438 | sigaddset(&(act.sa_mask), SIGUSR1); |
439 | sigaction(SIGUSR1, &act, NULL); |
e8efa18d |
440 | |
441 | act.sa_handler = handler_sigusr2; |
442 | act.sa_flags = 0; |
443 | sigemptyset(&(act.sa_mask)); |
444 | sigaddset(&(act.sa_mask), SIGUSR2); |
445 | sigaction(SIGUSR2, &act, NULL); |
446 | |
447 | act.sa_handler = handler_sigalarm; |
448 | act.sa_flags = 0; |
449 | sigemptyset(&(act.sa_mask)); |
450 | sigaddset(&(act.sa_mask), SIGALRM); |
451 | sigaction(SIGALRM, &act, NULL); |
452 | |
e8efa18d |
453 | alarm(3); |
454 | |
700d350d |
455 | while(1) { |
c095a20d |
456 | ret = sigsuspend(&oldset); |
457 | if(ret != -1) { |
458 | perror("LTT Error in sigsuspend\n"); |
459 | } |
a85b8f41 |
460 | if(traced_pid == 0) break; /* parent died */ |
e8efa18d |
461 | if(parent_exited) break; |
8a9103df |
462 | dbg_printf("LTT Doing a buffer switch read. pid is : %lu\n", getpid()); |
7076f16d |
463 | |
47d7d576 |
464 | do { |
b402c055 |
465 | ret = read_subbuffer(&shared_trace_info->channel.process, fd_process); |
47d7d576 |
466 | } while(ret == 0); |
700d350d |
467 | } |
32f2b04a |
468 | /* The parent thread is dead and we have finished with the buffer */ |
469 | |
470 | /* Buffer force switch (flush). Using FLUSH instead of ACTIVE because we know |
471 | * there is no writer. */ |
b402c055 |
472 | flush_buffer(&shared_trace_info->channel.process, FORCE_FLUSH); |
47d7d576 |
473 | do { |
b402c055 |
474 | ret = read_subbuffer(&shared_trace_info->channel.process, fd_process); |
47d7d576 |
475 | } while(ret == 0); |
476 | |
e0cd021d |
477 | if(fd_process != -1) |
478 | close(fd_process); |
77b31f39 |
479 | |
85b94320 |
480 | ret = sem_destroy(&shared_trace_info->channel.process.writer_sem); |
481 | if(ret < 0) { |
482 | perror("error in sem_destroy"); |
483 | } |
e8efa18d |
484 | munmap(shared_trace_info, sizeof(*shared_trace_info)); |
485 | |
486 | exit(0); |
700d350d |
487 | } |
b09f3215 |
488 | |
e8efa18d |
489 | |
490 | /* Reader-writer initialization */ |
491 | |
492 | static enum ltt_process_role { LTT_ROLE_WRITER, LTT_ROLE_READER } |
493 | role = LTT_ROLE_WRITER; |
494 | |
495 | |
496 | void ltt_rw_init(void) |
b09f3215 |
497 | { |
700d350d |
498 | pid_t pid; |
499 | struct ltt_trace_info *shared_trace_info; |
500 | int ret; |
501 | sigset_t set, oldset; |
a85b8f41 |
502 | pid_t l_traced_pid = getpid(); |
4c992ad5 |
503 | pid_t l_traced_tid = gettid(); |
700d350d |
504 | |
505 | /* parent : create the shared memory map */ |
a85b8f41 |
506 | shared_trace_info = mmap(0, sizeof(*thread_trace_info), |
700d350d |
507 | PROT_READ|PROT_WRITE, MAP_SHARED|MAP_ANONYMOUS, 0, 0); |
8a9103df |
508 | shared_trace_info->init=0; |
509 | shared_trace_info->filter=0; |
510 | shared_trace_info->daemon_id=0; |
511 | shared_trace_info->nesting=0; |
b402c055 |
512 | memset(&shared_trace_info->channel.process, 0, |
513 | sizeof(shared_trace_info->channel.process)); |
85b94320 |
514 | //Need NPTL! |
515 | ret = sem_init(&shared_trace_info->channel.process.writer_sem, 1, |
516 | LTT_N_SUBBUFS); |
517 | if(ret < 0) { |
518 | perror("error in sem_init"); |
519 | } |
b402c055 |
520 | shared_trace_info->channel.process.alloc_size = LTT_BUF_SIZE_PROCESS; |
521 | shared_trace_info->channel.process.subbuf_size = LTT_SUBBUF_SIZE_PROCESS; |
522 | shared_trace_info->channel.process.start = |
523 | shared_trace_info->channel.process_buf; |
524 | ltt_buffer_begin_callback(&shared_trace_info->channel.process, |
5ffa9d14 |
525 | ltt_get_timestamp(), 0); |
526 | |
a85b8f41 |
527 | shared_trace_info->init = 1; |
700d350d |
528 | |
529 | /* Disable signals */ |
530 | ret = sigfillset(&set); |
531 | if(ret) { |
8a9103df |
532 | dbg_printf("LTT Error in sigfillset\n"); |
700d350d |
533 | } |
534 | |
700d350d |
535 | ret = pthread_sigmask(SIG_BLOCK, &set, &oldset); |
536 | if(ret) { |
8a9103df |
537 | dbg_printf("LTT Error in pthread_sigmask\n"); |
700d350d |
538 | } |
a85b8f41 |
539 | |
700d350d |
540 | pid = fork(); |
541 | if(pid > 0) { |
542 | /* Parent */ |
a85b8f41 |
543 | shared_trace_info->daemon_id = pid; |
544 | thread_trace_info = shared_trace_info; |
700d350d |
545 | |
546 | /* Enable signals */ |
547 | ret = pthread_sigmask(SIG_SETMASK, &oldset, NULL); |
548 | if(ret) { |
8a9103df |
549 | dbg_printf("LTT Error in pthread_sigmask\n"); |
700d350d |
550 | } |
551 | } else if(pid == 0) { |
b5d612cb |
552 | pid_t sid; |
700d350d |
553 | /* Child */ |
e8efa18d |
554 | role = LTT_ROLE_READER; |
b5d612cb |
555 | sid = setsid(); |
b402c055 |
556 | //Not a good idea to renice, unless futex wait eventually implement |
557 | //priority inheritence. |
558 | //ret = nice(1); |
559 | //if(ret < 0) { |
560 | // perror("Error in nice"); |
561 | //} |
b5d612cb |
562 | if(sid < 0) { |
563 | perror("Error setting sid"); |
564 | } |
77b31f39 |
565 | ltt_usertrace_fast_daemon(shared_trace_info, oldset, l_traced_pid, |
4c992ad5 |
566 | l_traced_tid); |
700d350d |
567 | /* Should never return */ |
568 | exit(-1); |
569 | } else if(pid < 0) { |
570 | /* fork error */ |
a35eaa9c |
571 | perror("LTT Error in forking ltt-usertrace-fast"); |
700d350d |
572 | } |
b09f3215 |
573 | } |
574 | |
e8efa18d |
575 | static __thread struct _pthread_cleanup_buffer cleanup_buffer; |
576 | |
577 | void ltt_thread_init(void) |
578 | { |
579 | _pthread_cleanup_push(&cleanup_buffer, ltt_usertrace_fast_cleanup, NULL); |
580 | ltt_rw_init(); |
581 | } |
582 | |
04180f7f |
583 | void __attribute__((constructor)) __ltt_usertrace_fast_init(void) |
b09f3215 |
584 | { |
8a9103df |
585 | dbg_printf("LTT usertrace-fast init\n"); |
b09f3215 |
586 | |
e8efa18d |
587 | ltt_rw_init(); |
700d350d |
588 | } |
589 | |
590 | void __attribute__((destructor)) __ltt_usertrace_fast_fini(void) |
591 | { |
e8efa18d |
592 | if(role == LTT_ROLE_WRITER) { |
8a9103df |
593 | dbg_printf("LTT usertrace-fast fini\n"); |
e8efa18d |
594 | ltt_usertrace_fast_cleanup(NULL); |
595 | } |
b09f3215 |
596 | } |
597 | |