| 1 | /* |
| 2 | * Copyright (C) 2011 - Julien Desfossez <julien.desfossez@polymtl.ca> |
| 3 | * Mathieu Desnoyers <mathieu.desnoyers@efficios.com> |
| 4 | * |
| 5 | * This program is free software; you can redistribute it and/or modify |
| 6 | * it under the terms of the GNU General Public License, version 2 only, |
| 7 | * as published by the Free Software Foundation. |
| 8 | * |
| 9 | * This program is distributed in the hope that it will be useful, |
| 10 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 11 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 12 | * GNU General Public License for more details. |
| 13 | * |
| 14 | * You should have received a copy of the GNU General Public License along |
| 15 | * with this program; if not, write to the Free Software Foundation, Inc., |
| 16 | * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. |
| 17 | */ |
| 18 | |
| 19 | #define _GNU_SOURCE |
| 20 | #include <assert.h> |
| 21 | #include <poll.h> |
| 22 | #include <pthread.h> |
| 23 | #include <stdlib.h> |
| 24 | #include <string.h> |
| 25 | #include <sys/mman.h> |
| 26 | #include <sys/socket.h> |
| 27 | #include <sys/stat.h> |
| 28 | #include <sys/types.h> |
| 29 | #include <unistd.h> |
| 30 | #include <lttng/ust-ctl.h> |
| 31 | |
| 32 | #include <common/common.h> |
| 33 | #include <common/sessiond-comm/sessiond-comm.h> |
| 34 | #include <common/relayd/relayd.h> |
| 35 | #include <common/compat/fcntl.h> |
| 36 | |
| 37 | #include "ust-consumer.h" |
| 38 | |
| 39 | extern struct lttng_consumer_global_data consumer_data; |
| 40 | extern int consumer_poll_timeout; |
| 41 | extern volatile int consumer_quit; |
| 42 | |
| 43 | /* |
| 44 | * Mmap the ring buffer, read it and write the data to the tracefile. |
| 45 | * |
| 46 | * Returns the number of bytes written, else negative value on error. |
| 47 | */ |
| 48 | ssize_t lttng_ustconsumer_on_read_subbuffer_mmap( |
| 49 | struct lttng_consumer_local_data *ctx, |
| 50 | struct lttng_consumer_stream *stream, unsigned long len) |
| 51 | { |
| 52 | unsigned long mmap_offset; |
| 53 | long ret = 0, written = 0; |
| 54 | off_t orig_offset = stream->out_fd_offset; |
| 55 | int outfd = stream->out_fd; |
| 56 | uint64_t metadata_id; |
| 57 | struct consumer_relayd_sock_pair *relayd = NULL; |
| 58 | |
| 59 | /* RCU lock for the relayd pointer */ |
| 60 | rcu_read_lock(); |
| 61 | |
| 62 | /* Flag that the current stream if set for network streaming. */ |
| 63 | if (stream->net_seq_idx != -1) { |
| 64 | relayd = consumer_find_relayd(stream->net_seq_idx); |
| 65 | if (relayd == NULL) { |
| 66 | ERR("UST consumer mmap(), unable to find relay for index %d", |
| 67 | stream->net_seq_idx); |
| 68 | goto end; |
| 69 | } |
| 70 | } |
| 71 | |
| 72 | /* get the offset inside the fd to mmap */ |
| 73 | ret = ustctl_get_mmap_read_offset(stream->chan->handle, |
| 74 | stream->buf, &mmap_offset); |
| 75 | if (ret != 0) { |
| 76 | errno = -ret; |
| 77 | PERROR("ustctl_get_mmap_read_offset"); |
| 78 | written = ret; |
| 79 | goto end; |
| 80 | } |
| 81 | |
| 82 | /* Handle stream on the relayd if the output is on the network */ |
| 83 | if (relayd) { |
| 84 | unsigned long netlen = len; |
| 85 | |
| 86 | if (stream->metadata_flag) { |
| 87 | /* Only lock if metadata since we use the control socket. */ |
| 88 | pthread_mutex_lock(&relayd->ctrl_sock_mutex); |
| 89 | netlen += sizeof(stream->relayd_stream_id); |
| 90 | } |
| 91 | |
| 92 | ret = consumer_handle_stream_before_relayd(stream, netlen); |
| 93 | if (ret >= 0) { |
| 94 | outfd = ret; |
| 95 | |
| 96 | /* Write metadata stream id before payload */ |
| 97 | if (stream->metadata_flag) { |
| 98 | metadata_id = htobe64(stream->relayd_stream_id); |
| 99 | do { |
| 100 | ret = write(outfd, (void *) &metadata_id, |
| 101 | sizeof(stream->relayd_stream_id)); |
| 102 | } while (ret < 0 && errno == EINTR); |
| 103 | if (ret < 0) { |
| 104 | PERROR("write metadata stream id"); |
| 105 | written = ret; |
| 106 | goto end; |
| 107 | } |
| 108 | DBG("Metadata stream id %zu written before data", |
| 109 | stream->relayd_stream_id); |
| 110 | } |
| 111 | } |
| 112 | /* Else, use the default set before which is the filesystem. */ |
| 113 | } |
| 114 | |
| 115 | while (len > 0) { |
| 116 | do { |
| 117 | ret = write(outfd, stream->mmap_base + mmap_offset, len); |
| 118 | } while (ret < 0 && errno == EINTR); |
| 119 | if (ret < 0) { |
| 120 | PERROR("Error in file write"); |
| 121 | if (written == 0) { |
| 122 | written = ret; |
| 123 | } |
| 124 | goto end; |
| 125 | } else if (ret > len) { |
| 126 | PERROR("ret %ld > len %lu", ret, len); |
| 127 | written += ret; |
| 128 | goto end; |
| 129 | } else { |
| 130 | len -= ret; |
| 131 | mmap_offset += ret; |
| 132 | } |
| 133 | DBG("UST mmap write() ret %ld (len %lu)", ret, len); |
| 134 | |
| 135 | /* This call is useless on a socket so better save a syscall. */ |
| 136 | if (!relayd) { |
| 137 | /* This won't block, but will start writeout asynchronously */ |
| 138 | lttng_sync_file_range(outfd, stream->out_fd_offset, ret, |
| 139 | SYNC_FILE_RANGE_WRITE); |
| 140 | stream->out_fd_offset += ret; |
| 141 | } |
| 142 | written += ret; |
| 143 | } |
| 144 | lttng_consumer_sync_trace_file(stream, orig_offset); |
| 145 | |
| 146 | end: |
| 147 | if (relayd && stream->metadata_flag) { |
| 148 | pthread_mutex_unlock(&relayd->ctrl_sock_mutex); |
| 149 | } |
| 150 | rcu_read_unlock(); |
| 151 | return written; |
| 152 | } |
| 153 | |
| 154 | /* |
| 155 | * Splice the data from the ring buffer to the tracefile. |
| 156 | * |
| 157 | * Returns the number of bytes spliced. |
| 158 | */ |
| 159 | ssize_t lttng_ustconsumer_on_read_subbuffer_splice( |
| 160 | struct lttng_consumer_local_data *ctx, |
| 161 | struct lttng_consumer_stream *stream, unsigned long len) |
| 162 | { |
| 163 | return -ENOSYS; |
| 164 | } |
| 165 | |
| 166 | /* |
| 167 | * Take a snapshot for a specific fd |
| 168 | * |
| 169 | * Returns 0 on success, < 0 on error |
| 170 | */ |
| 171 | int lttng_ustconsumer_take_snapshot(struct lttng_consumer_local_data *ctx, |
| 172 | struct lttng_consumer_stream *stream) |
| 173 | { |
| 174 | int ret = 0; |
| 175 | |
| 176 | ret = ustctl_snapshot(stream->chan->handle, stream->buf); |
| 177 | if (ret != 0) { |
| 178 | errno = -ret; |
| 179 | PERROR("Getting sub-buffer snapshot."); |
| 180 | } |
| 181 | |
| 182 | return ret; |
| 183 | } |
| 184 | |
| 185 | /* |
| 186 | * Get the produced position |
| 187 | * |
| 188 | * Returns 0 on success, < 0 on error |
| 189 | */ |
| 190 | int lttng_ustconsumer_get_produced_snapshot( |
| 191 | struct lttng_consumer_local_data *ctx, |
| 192 | struct lttng_consumer_stream *stream, |
| 193 | unsigned long *pos) |
| 194 | { |
| 195 | int ret; |
| 196 | |
| 197 | ret = ustctl_snapshot_get_produced(stream->chan->handle, |
| 198 | stream->buf, pos); |
| 199 | if (ret != 0) { |
| 200 | errno = -ret; |
| 201 | PERROR("kernctl_snapshot_get_produced"); |
| 202 | } |
| 203 | |
| 204 | return ret; |
| 205 | } |
| 206 | |
| 207 | int lttng_ustconsumer_recv_cmd(struct lttng_consumer_local_data *ctx, |
| 208 | int sock, struct pollfd *consumer_sockpoll) |
| 209 | { |
| 210 | ssize_t ret; |
| 211 | struct lttcomm_consumer_msg msg; |
| 212 | |
| 213 | ret = lttcomm_recv_unix_sock(sock, &msg, sizeof(msg)); |
| 214 | if (ret != sizeof(msg)) { |
| 215 | DBG("Consumer received unexpected message size %zd (expects %zu)", |
| 216 | ret, sizeof(msg)); |
| 217 | lttng_consumer_send_error(ctx, CONSUMERD_ERROR_RECV_FD); |
| 218 | return ret; |
| 219 | } |
| 220 | if (msg.cmd_type == LTTNG_CONSUMER_STOP) { |
| 221 | return -ENOENT; |
| 222 | } |
| 223 | |
| 224 | /* relayd need RCU read-side lock */ |
| 225 | rcu_read_lock(); |
| 226 | |
| 227 | switch (msg.cmd_type) { |
| 228 | case LTTNG_CONSUMER_ADD_RELAYD_SOCKET: |
| 229 | { |
| 230 | int fd; |
| 231 | struct consumer_relayd_sock_pair *relayd; |
| 232 | |
| 233 | DBG("UST Consumer adding relayd socket"); |
| 234 | |
| 235 | /* Get relayd reference if exists. */ |
| 236 | relayd = consumer_find_relayd(msg.u.relayd_sock.net_index); |
| 237 | if (relayd == NULL) { |
| 238 | /* Not found. Allocate one. */ |
| 239 | relayd = consumer_allocate_relayd_sock_pair( |
| 240 | msg.u.relayd_sock.net_index); |
| 241 | if (relayd == NULL) { |
| 242 | lttng_consumer_send_error(ctx, CONSUMERD_OUTFD_ERROR); |
| 243 | goto end_nosignal; |
| 244 | } |
| 245 | } |
| 246 | |
| 247 | /* Poll on consumer socket. */ |
| 248 | if (lttng_consumer_poll_socket(consumer_sockpoll) < 0) { |
| 249 | return -EINTR; |
| 250 | } |
| 251 | |
| 252 | /* Get relayd socket from session daemon */ |
| 253 | ret = lttcomm_recv_fds_unix_sock(sock, &fd, 1); |
| 254 | if (ret != sizeof(fd)) { |
| 255 | lttng_consumer_send_error(ctx, CONSUMERD_ERROR_RECV_FD); |
| 256 | goto end_nosignal; |
| 257 | } |
| 258 | |
| 259 | /* Copy socket information and received FD */ |
| 260 | switch (msg.u.relayd_sock.type) { |
| 261 | case LTTNG_STREAM_CONTROL: |
| 262 | /* Copy received lttcomm socket */ |
| 263 | lttcomm_copy_sock(&relayd->control_sock, &msg.u.relayd_sock.sock); |
| 264 | ret = lttcomm_create_sock(&relayd->control_sock); |
| 265 | if (ret < 0) { |
| 266 | goto end_nosignal; |
| 267 | } |
| 268 | |
| 269 | /* Close the created socket fd which is useless */ |
| 270 | close(relayd->control_sock.fd); |
| 271 | |
| 272 | /* Assign new file descriptor */ |
| 273 | relayd->control_sock.fd = fd; |
| 274 | break; |
| 275 | case LTTNG_STREAM_DATA: |
| 276 | /* Copy received lttcomm socket */ |
| 277 | lttcomm_copy_sock(&relayd->data_sock, &msg.u.relayd_sock.sock); |
| 278 | ret = lttcomm_create_sock(&relayd->data_sock); |
| 279 | if (ret < 0) { |
| 280 | goto end_nosignal; |
| 281 | } |
| 282 | |
| 283 | /* Close the created socket fd which is useless */ |
| 284 | close(relayd->data_sock.fd); |
| 285 | |
| 286 | /* Assign new file descriptor */ |
| 287 | relayd->data_sock.fd = fd; |
| 288 | break; |
| 289 | default: |
| 290 | ERR("Unknown relayd socket type"); |
| 291 | goto end_nosignal; |
| 292 | } |
| 293 | |
| 294 | DBG("Consumer %s socket created successfully with net idx %d (fd: %d)", |
| 295 | msg.u.relayd_sock.type == LTTNG_STREAM_CONTROL ? "control" : "data", |
| 296 | relayd->net_seq_idx, fd); |
| 297 | |
| 298 | /* |
| 299 | * Add relayd socket pair to consumer data hashtable. If object already |
| 300 | * exists or on error, the function gracefully returns. |
| 301 | */ |
| 302 | consumer_add_relayd(relayd); |
| 303 | |
| 304 | goto end_nosignal; |
| 305 | } |
| 306 | case LTTNG_CONSUMER_ADD_CHANNEL: |
| 307 | { |
| 308 | struct lttng_consumer_channel *new_channel; |
| 309 | int fds[1]; |
| 310 | size_t nb_fd = 1; |
| 311 | |
| 312 | DBG("UST Consumer adding channel"); |
| 313 | |
| 314 | /* block */ |
| 315 | if (lttng_consumer_poll_socket(consumer_sockpoll) < 0) { |
| 316 | return -EINTR; |
| 317 | } |
| 318 | ret = lttcomm_recv_fds_unix_sock(sock, fds, nb_fd); |
| 319 | if (ret != sizeof(fds)) { |
| 320 | lttng_consumer_send_error(ctx, CONSUMERD_ERROR_RECV_FD); |
| 321 | return ret; |
| 322 | } |
| 323 | |
| 324 | DBG("consumer_add_channel %d", msg.u.channel.channel_key); |
| 325 | |
| 326 | new_channel = consumer_allocate_channel(msg.u.channel.channel_key, |
| 327 | fds[0], -1, |
| 328 | msg.u.channel.mmap_len, |
| 329 | msg.u.channel.max_sb_size); |
| 330 | if (new_channel == NULL) { |
| 331 | lttng_consumer_send_error(ctx, CONSUMERD_OUTFD_ERROR); |
| 332 | goto end_nosignal; |
| 333 | } |
| 334 | if (ctx->on_recv_channel != NULL) { |
| 335 | ret = ctx->on_recv_channel(new_channel); |
| 336 | if (ret == 0) { |
| 337 | consumer_add_channel(new_channel); |
| 338 | } else if (ret < 0) { |
| 339 | goto end_nosignal; |
| 340 | } |
| 341 | } else { |
| 342 | consumer_add_channel(new_channel); |
| 343 | } |
| 344 | goto end_nosignal; |
| 345 | } |
| 346 | case LTTNG_CONSUMER_ADD_STREAM: |
| 347 | { |
| 348 | struct lttng_consumer_stream *new_stream; |
| 349 | int fds[2]; |
| 350 | size_t nb_fd = 2; |
| 351 | struct consumer_relayd_sock_pair *relayd = NULL; |
| 352 | |
| 353 | DBG("UST Consumer adding stream"); |
| 354 | |
| 355 | /* block */ |
| 356 | if (lttng_consumer_poll_socket(consumer_sockpoll) < 0) { |
| 357 | return -EINTR; |
| 358 | } |
| 359 | ret = lttcomm_recv_fds_unix_sock(sock, fds, nb_fd); |
| 360 | if (ret != sizeof(fds)) { |
| 361 | lttng_consumer_send_error(ctx, CONSUMERD_ERROR_RECV_FD); |
| 362 | return ret; |
| 363 | } |
| 364 | |
| 365 | DBG("consumer_add_stream chan %d stream %d", |
| 366 | msg.u.stream.channel_key, |
| 367 | msg.u.stream.stream_key); |
| 368 | |
| 369 | assert(msg.u.stream.output == LTTNG_EVENT_MMAP); |
| 370 | new_stream = consumer_allocate_stream(msg.u.stream.channel_key, |
| 371 | msg.u.stream.stream_key, |
| 372 | fds[0], fds[1], |
| 373 | msg.u.stream.state, |
| 374 | msg.u.stream.mmap_len, |
| 375 | msg.u.stream.output, |
| 376 | msg.u.stream.path_name, |
| 377 | msg.u.stream.uid, |
| 378 | msg.u.stream.gid, |
| 379 | msg.u.stream.net_index, |
| 380 | msg.u.stream.metadata_flag); |
| 381 | if (new_stream == NULL) { |
| 382 | lttng_consumer_send_error(ctx, CONSUMERD_OUTFD_ERROR); |
| 383 | goto end; |
| 384 | } |
| 385 | |
| 386 | /* The stream is not metadata. Get relayd reference if exists. */ |
| 387 | relayd = consumer_find_relayd(msg.u.stream.net_index); |
| 388 | if (relayd != NULL) { |
| 389 | pthread_mutex_lock(&relayd->ctrl_sock_mutex); |
| 390 | /* Add stream on the relayd */ |
| 391 | ret = relayd_add_stream(&relayd->control_sock, |
| 392 | msg.u.stream.name, msg.u.stream.path_name, |
| 393 | &new_stream->relayd_stream_id); |
| 394 | pthread_mutex_unlock(&relayd->ctrl_sock_mutex); |
| 395 | if (ret < 0) { |
| 396 | goto end; |
| 397 | } |
| 398 | } else if (msg.u.stream.net_index != -1) { |
| 399 | ERR("Network sequence index %d unknown. Not adding stream.", |
| 400 | msg.u.stream.net_index); |
| 401 | free(new_stream); |
| 402 | goto end; |
| 403 | } |
| 404 | |
| 405 | if (ctx->on_recv_stream != NULL) { |
| 406 | ret = ctx->on_recv_stream(new_stream); |
| 407 | if (ret == 0) { |
| 408 | consumer_add_stream(new_stream); |
| 409 | } else if (ret < 0) { |
| 410 | goto end; |
| 411 | } |
| 412 | } else { |
| 413 | consumer_add_stream(new_stream); |
| 414 | } |
| 415 | |
| 416 | DBG("UST consumer_add_stream %s (%d,%d) with relayd id %lu", |
| 417 | msg.u.stream.path_name, fds[0], fds[1], |
| 418 | new_stream->relayd_stream_id); |
| 419 | break; |
| 420 | } |
| 421 | case LTTNG_CONSUMER_DESTROY_RELAYD: |
| 422 | { |
| 423 | struct consumer_relayd_sock_pair *relayd; |
| 424 | |
| 425 | DBG("UST consumer destroying relayd %zu", |
| 426 | msg.u.destroy_relayd.net_seq_idx); |
| 427 | |
| 428 | /* Get relayd reference if exists. */ |
| 429 | relayd = consumer_find_relayd(msg.u.destroy_relayd.net_seq_idx); |
| 430 | if (relayd == NULL) { |
| 431 | ERR("Unable to find relayd %zu", |
| 432 | msg.u.destroy_relayd.net_seq_idx); |
| 433 | } |
| 434 | |
| 435 | /* Set destroy flag for this object */ |
| 436 | uatomic_set(&relayd->destroy_flag, 1); |
| 437 | |
| 438 | /* Destroy the relayd if refcount is 0 else set the destroy flag. */ |
| 439 | if (uatomic_read(&relayd->refcount) == 0) { |
| 440 | consumer_destroy_relayd(relayd); |
| 441 | } |
| 442 | break; |
| 443 | } |
| 444 | case LTTNG_CONSUMER_UPDATE_STREAM: |
| 445 | { |
| 446 | return -ENOSYS; |
| 447 | #if 0 |
| 448 | if (ctx->on_update_stream != NULL) { |
| 449 | ret = ctx->on_update_stream(msg.u.stream.stream_key, msg.u.stream.state); |
| 450 | if (ret == 0) { |
| 451 | consumer_change_stream_state(msg.u.stream.stream_key, msg.u.stream.state); |
| 452 | } else if (ret < 0) { |
| 453 | goto end; |
| 454 | } |
| 455 | } else { |
| 456 | consumer_change_stream_state(msg.u.stream.stream_key, |
| 457 | msg.u.stream.state); |
| 458 | } |
| 459 | #endif |
| 460 | break; |
| 461 | } |
| 462 | default: |
| 463 | break; |
| 464 | } |
| 465 | end: |
| 466 | /* |
| 467 | * Wake-up the other end by writing a null byte in the pipe |
| 468 | * (non-blocking). Important note: Because writing into the |
| 469 | * pipe is non-blocking (and therefore we allow dropping wakeup |
| 470 | * data, as long as there is wakeup data present in the pipe |
| 471 | * buffer to wake up the other end), the other end should |
| 472 | * perform the following sequence for waiting: |
| 473 | * 1) empty the pipe (reads). |
| 474 | * 2) perform update operation. |
| 475 | * 3) wait on the pipe (poll). |
| 476 | */ |
| 477 | do { |
| 478 | ret = write(ctx->consumer_poll_pipe[1], "", 1); |
| 479 | } while (ret < 0 && errno == EINTR); |
| 480 | end_nosignal: |
| 481 | rcu_read_unlock(); |
| 482 | return 0; |
| 483 | } |
| 484 | |
| 485 | int lttng_ustconsumer_allocate_channel(struct lttng_consumer_channel *chan) |
| 486 | { |
| 487 | struct lttng_ust_object_data obj; |
| 488 | |
| 489 | obj.handle = -1; |
| 490 | obj.shm_fd = chan->shm_fd; |
| 491 | obj.wait_fd = chan->wait_fd; |
| 492 | obj.memory_map_size = chan->mmap_len; |
| 493 | chan->handle = ustctl_map_channel(&obj); |
| 494 | if (!chan->handle) { |
| 495 | return -ENOMEM; |
| 496 | } |
| 497 | chan->wait_fd_is_copy = 1; |
| 498 | chan->shm_fd = -1; |
| 499 | |
| 500 | return 0; |
| 501 | } |
| 502 | |
| 503 | void lttng_ustconsumer_on_stream_hangup(struct lttng_consumer_stream *stream) |
| 504 | { |
| 505 | ustctl_flush_buffer(stream->chan->handle, stream->buf, 0); |
| 506 | stream->hangup_flush_done = 1; |
| 507 | } |
| 508 | |
| 509 | void lttng_ustconsumer_del_channel(struct lttng_consumer_channel *chan) |
| 510 | { |
| 511 | ustctl_unmap_channel(chan->handle); |
| 512 | } |
| 513 | |
| 514 | int lttng_ustconsumer_allocate_stream(struct lttng_consumer_stream *stream) |
| 515 | { |
| 516 | struct lttng_ust_object_data obj; |
| 517 | int ret; |
| 518 | |
| 519 | obj.handle = -1; |
| 520 | obj.shm_fd = stream->shm_fd; |
| 521 | obj.wait_fd = stream->wait_fd; |
| 522 | obj.memory_map_size = stream->mmap_len; |
| 523 | ret = ustctl_add_stream(stream->chan->handle, &obj); |
| 524 | if (ret) |
| 525 | return ret; |
| 526 | stream->buf = ustctl_open_stream_read(stream->chan->handle, stream->cpu); |
| 527 | if (!stream->buf) |
| 528 | return -EBUSY; |
| 529 | /* ustctl_open_stream_read has closed the shm fd. */ |
| 530 | stream->wait_fd_is_copy = 1; |
| 531 | stream->shm_fd = -1; |
| 532 | |
| 533 | stream->mmap_base = ustctl_get_mmap_base(stream->chan->handle, stream->buf); |
| 534 | if (!stream->mmap_base) { |
| 535 | return -EINVAL; |
| 536 | } |
| 537 | |
| 538 | return 0; |
| 539 | } |
| 540 | |
| 541 | void lttng_ustconsumer_del_stream(struct lttng_consumer_stream *stream) |
| 542 | { |
| 543 | ustctl_close_stream_read(stream->chan->handle, stream->buf); |
| 544 | } |
| 545 | |
| 546 | |
| 547 | int lttng_ustconsumer_read_subbuffer(struct lttng_consumer_stream *stream, |
| 548 | struct lttng_consumer_local_data *ctx) |
| 549 | { |
| 550 | unsigned long len; |
| 551 | int err; |
| 552 | long ret = 0; |
| 553 | struct lttng_ust_shm_handle *handle; |
| 554 | struct lttng_ust_lib_ring_buffer *buf; |
| 555 | char dummy; |
| 556 | ssize_t readlen; |
| 557 | |
| 558 | DBG("In read_subbuffer (wait_fd: %d, stream key: %d)", |
| 559 | stream->wait_fd, stream->key); |
| 560 | |
| 561 | /* We can consume the 1 byte written into the wait_fd by UST */ |
| 562 | if (!stream->hangup_flush_done) { |
| 563 | do { |
| 564 | readlen = read(stream->wait_fd, &dummy, 1); |
| 565 | } while (readlen == -1 && errno == EINTR); |
| 566 | if (readlen == -1) { |
| 567 | ret = readlen; |
| 568 | goto end; |
| 569 | } |
| 570 | } |
| 571 | |
| 572 | buf = stream->buf; |
| 573 | handle = stream->chan->handle; |
| 574 | /* Get the next subbuffer */ |
| 575 | err = ustctl_get_next_subbuf(handle, buf); |
| 576 | if (err != 0) { |
| 577 | ret = -ret; /* ustctl_get_next_subbuf returns negative, caller expect positive. */ |
| 578 | /* |
| 579 | * This is a debug message even for single-threaded consumer, |
| 580 | * because poll() have more relaxed criterions than get subbuf, |
| 581 | * so get_subbuf may fail for short race windows where poll() |
| 582 | * would issue wakeups. |
| 583 | */ |
| 584 | DBG("Reserving sub buffer failed (everything is normal, " |
| 585 | "it is due to concurrency)"); |
| 586 | goto end; |
| 587 | } |
| 588 | assert(stream->output == LTTNG_EVENT_MMAP); |
| 589 | /* read the used subbuffer size */ |
| 590 | err = ustctl_get_padded_subbuf_size(handle, buf, &len); |
| 591 | assert(err == 0); |
| 592 | /* write the subbuffer to the tracefile */ |
| 593 | ret = lttng_consumer_on_read_subbuffer_mmap(ctx, stream, len); |
| 594 | if (ret != len) { |
| 595 | /* |
| 596 | * display the error but continue processing to try |
| 597 | * to release the subbuffer |
| 598 | */ |
| 599 | ERR("Error writing to tracefile"); |
| 600 | } |
| 601 | err = ustctl_put_next_subbuf(handle, buf); |
| 602 | assert(err == 0); |
| 603 | end: |
| 604 | return ret; |
| 605 | } |
| 606 | |
| 607 | int lttng_ustconsumer_on_recv_stream(struct lttng_consumer_stream *stream) |
| 608 | { |
| 609 | int ret; |
| 610 | |
| 611 | /* Opening the tracefile in write mode */ |
| 612 | if (stream->path_name != NULL && stream->net_seq_idx == -1) { |
| 613 | ret = run_as_open(stream->path_name, |
| 614 | O_WRONLY|O_CREAT|O_TRUNC, |
| 615 | S_IRWXU|S_IRWXG|S_IRWXO, |
| 616 | stream->uid, stream->gid); |
| 617 | if (ret < 0) { |
| 618 | ERR("Opening %s", stream->path_name); |
| 619 | PERROR("open"); |
| 620 | goto error; |
| 621 | } |
| 622 | stream->out_fd = ret; |
| 623 | } |
| 624 | |
| 625 | /* we return 0 to let the library handle the FD internally */ |
| 626 | return 0; |
| 627 | |
| 628 | error: |
| 629 | return ret; |
| 630 | } |