src/bin/lttng-sessiond/consumer.c

   1 /*
   2  * Copyright (C) 2012 - David Goulet <dgoulet@efficios.com>
   3  *
   4  * This program is free software; you can redistribute it and/or modify it
   5  * under the terms of the GNU General Public License, version 2 only, as
   6  * published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful, but WITHOUT
   9  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  10  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  11  * more details.
  12  *
  13  * You should have received a copy of the GNU General Public License along with
  14  * this program; if not, write to the Free Software Foundation, Inc., 51
  15  * Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  16  */
  17
  18 #define _GNU_SOURCE
  19 #include <assert.h>
  20 #include <stdio.h>
  21 #include <stdlib.h>
  22 #include <string.h>
  23 #include <sys/stat.h>
  24 #include <sys/types.h>
  25 #include <unistd.h>
  26
  27 #include <common/common.h>
  28 #include <common/defaults.h>
  29 #include <common/uri.h>
  30
  31 #include "consumer.h"
  32
  33 /*
  34  * Receive a reply command status message from the consumer. Consumer socket
  35  * lock MUST be acquired before calling this function.
  36  *
  37  * Return 0 on success, -1 on recv error or a negative lttng error code which
  38  * was possibly returned by the consumer.
  39  */
  40 int consumer_recv_status_reply(struct consumer_socket *sock)
  41 {
  42         int ret;
  43         struct lttcomm_consumer_status_msg reply;
  44
  45         assert(sock);
  46
  47         ret = lttcomm_recv_unix_sock(sock->fd, &reply, sizeof(reply));
  48         if (ret <= 0) {
  49                 if (ret == 0) {
  50                         /* Orderly shutdown. Don't return 0 which means success. */
  51                         ret = -1;
  52                 }
  53                 /* The above call will print a PERROR on error. */
  54                 DBG("Fail to receive status reply on sock %d", sock->fd);
  55                 goto end;
  56         }
  57
  58         if (reply.ret_code == LTTNG_OK) {
  59                 /* All good. */
  60                 ret = 0;
  61         } else {
  62                 ret = -reply.ret_code;
  63                 DBG("Consumer ret code %d", reply.ret_code);
  64         }
  65
  66 end:
  67         return ret;
  68 }
  69
  70 /*
  71  * Send destroy relayd command to consumer.
  72  *
  73  * On success return positive value. On error, negative value.
  74  */
  75 int consumer_send_destroy_relayd(struct consumer_socket *sock,
  76                 struct consumer_output *consumer)
  77 {
  78         int ret;
  79         struct lttcomm_consumer_msg msg;
  80
  81         assert(consumer);
  82         assert(sock);
  83
  84         DBG2("Sending destroy relayd command to consumer...");
  85
  86         /* Bail out if consumer is disabled */
  87         if (!consumer->enabled) {
  88                 ret = LTTNG_OK;
  89                 DBG3("Consumer is disabled");
  90                 goto error;
  91         }
  92
  93         msg.cmd_type = LTTNG_CONSUMER_DESTROY_RELAYD;
  94         msg.u.destroy_relayd.net_seq_idx = consumer->net_seq_index;
  95
  96         pthread_mutex_lock(sock->lock);
  97         ret = lttcomm_send_unix_sock(sock->fd, &msg, sizeof(msg));
  98         if (ret < 0) {
  99                 /* Indicate that the consumer is probably closing at this point. */
 100                 DBG("send consumer destroy relayd command");
 101                 goto error_send;
 102         }
 103
 104         /* Don't check the return value. The caller will do it. */
 105         ret = consumer_recv_status_reply(sock);
 106
 107         DBG2("Consumer send destroy relayd command done");
 108
 109 error_send:
 110         pthread_mutex_unlock(sock->lock);
 111 error:
 112         return ret;
 113 }
 114
 115 /*
 116  * For each consumer socket in the consumer output object, send a destroy
 117  * relayd command.
 118  */
 119 void consumer_output_send_destroy_relayd(struct consumer_output *consumer)
 120 {
 121         struct lttng_ht_iter iter;
 122         struct consumer_socket *socket;
 123
 124         assert(consumer);
 125
 126         /* Destroy any relayd connection */
 127         if (consumer && consumer->type == CONSUMER_DST_NET) {
 128                 rcu_read_lock();
 129                 cds_lfht_for_each_entry(consumer->socks->ht, &iter.iter, socket,
 130                                 node.node) {
 131                         int ret;
 132
 133                         /* Send destroy relayd command */
 134                         ret = consumer_send_destroy_relayd(socket, consumer);
 135                         if (ret < 0) {
 136                                 DBG("Unable to send destroy relayd command to consumer");
 137                                 /* Continue since we MUST delete everything at this point. */
 138                         }
 139                 }
 140                 rcu_read_unlock();
 141         }
 142 }
 143
 144 /*
 145  * From a consumer_data structure, allocate and add a consumer socket to the
 146  * consumer output.
 147  *
 148  * Return 0 on success, else negative value on error
 149  */
 150 int consumer_create_socket(struct consumer_data *data,
 151                 struct consumer_output *output)
 152 {
 153         int ret = 0;
 154         struct consumer_socket *socket;
 155
 156         assert(data);
 157
 158         if (output == NULL || data->cmd_sock < 0) {
 159                 /*
 160                  * Not an error. Possible there is simply not spawned consumer or it's
 161                  * disabled for the tracing session asking the socket.
 162                  */
 163                 goto error;
 164         }
 165
 166         rcu_read_lock();
 167         socket = consumer_find_socket(data->cmd_sock, output);
 168         rcu_read_unlock();
 169         if (socket == NULL) {
 170                 socket = consumer_allocate_socket(data->cmd_sock);
 171                 if (socket == NULL) {
 172                         ret = -1;
 173                         goto error;
 174                 }
 175
 176                 socket->registered = 0;
 177                 socket->lock = &data->lock;
 178                 rcu_read_lock();
 179                 consumer_add_socket(socket, output);
 180                 rcu_read_unlock();
 181         }
 182
 183         DBG3("Consumer socket created (fd: %d) and added to output",
 184                         data->cmd_sock);
 185
 186 error:
 187         return ret;
 188 }
 189
 190 /*
 191  * Find a consumer_socket in a consumer_output hashtable. Read side lock must
 192  * be acquired before calling this function and across use of the
 193  * returned consumer_socket.
 194  */
 195 struct consumer_socket *consumer_find_socket(int key,
 196                 struct consumer_output *consumer)
 197 {
 198         struct lttng_ht_iter iter;
 199         struct lttng_ht_node_ulong *node;
 200         struct consumer_socket *socket = NULL;
 201
 202         /* Negative keys are lookup failures */
 203         if (key < 0 || consumer == NULL) {
 204                 return NULL;
 205         }
 206
 207         lttng_ht_lookup(consumer->socks, (void *)((unsigned long) key),
 208                         &iter);
 209         node = lttng_ht_iter_get_node_ulong(&iter);
 210         if (node != NULL) {
 211                 socket = caa_container_of(node, struct consumer_socket, node);
 212         }
 213
 214         return socket;
 215 }
 216
 217 /*
 218  * Allocate a new consumer_socket and return the pointer.
 219  */
 220 struct consumer_socket *consumer_allocate_socket(int fd)
 221 {
 222         struct consumer_socket *socket = NULL;
 223
 224         socket = zmalloc(sizeof(struct consumer_socket));
 225         if (socket == NULL) {
 226                 PERROR("zmalloc consumer socket");
 227                 goto error;
 228         }
 229
 230         socket->fd = fd;
 231         lttng_ht_node_init_ulong(&socket->node, fd);
 232
 233 error:
 234         return socket;
 235 }
 236
 237 /*
 238  * Add consumer socket to consumer output object. Read side lock must be
 239  * acquired before calling this function.
 240  */
 241 void consumer_add_socket(struct consumer_socket *sock,
 242                 struct consumer_output *consumer)
 243 {
 244         assert(sock);
 245         assert(consumer);
 246
 247         lttng_ht_add_unique_ulong(consumer->socks, &sock->node);
 248 }
 249
 250 /*
 251  * Delte consumer socket to consumer output object. Read side lock must be
 252  * acquired before calling this function.
 253  */
 254 void consumer_del_socket(struct consumer_socket *sock,
 255                 struct consumer_output *consumer)
 256 {
 257         int ret;
 258         struct lttng_ht_iter iter;
 259
 260         assert(sock);
 261         assert(consumer);
 262
 263         iter.iter.node = &sock->node.node;
 264         ret = lttng_ht_del(consumer->socks, &iter);
 265         assert(!ret);
 266 }
 267
 268 /*
 269  * RCU destroy call function.
 270  */
 271 static void destroy_socket_rcu(struct rcu_head *head)
 272 {
 273         struct lttng_ht_node_ulong *node =
 274                 caa_container_of(head, struct lttng_ht_node_ulong, head);
 275         struct consumer_socket *socket =
 276                 caa_container_of(node, struct consumer_socket, node);
 277
 278         free(socket);
 279 }
 280
 281 /*
 282  * Destroy and free socket pointer in a call RCU. Read side lock must be
 283  * acquired before calling this function.
 284  */
 285 void consumer_destroy_socket(struct consumer_socket *sock)
 286 {
 287         assert(sock);
 288
 289         /*
 290          * We DO NOT close the file descriptor here since it is global to the
 291          * session daemon and is closed only if the consumer dies or a custom
 292          * consumer was registered,
 293          */
 294         if (sock->registered) {
 295                 DBG3("Consumer socket was registered. Closing fd %d", sock->fd);
 296                 lttcomm_close_unix_sock(sock->fd);
 297         }
 298
 299         call_rcu(&sock->node.head, destroy_socket_rcu);
 300 }
 301
 302 /*
 303  * Allocate and assign data to a consumer_output object.
 304  *
 305  * Return pointer to structure.
 306  */
 307 struct consumer_output *consumer_create_output(enum consumer_dst_type type)
 308 {
 309         struct consumer_output *output = NULL;
 310
 311         output = zmalloc(sizeof(struct consumer_output));
 312         if (output == NULL) {
 313                 PERROR("zmalloc consumer_output");
 314                 goto error;
 315         }
 316
 317         /* By default, consumer output is enabled */
 318         output->enabled = 1;
 319         output->type = type;
 320         output->net_seq_index = -1;
 321
 322         output->socks = lttng_ht_new(0, LTTNG_HT_TYPE_ULONG);
 323
 324 error:
 325         return output;
 326 }
 327
 328 /*
 329  * Delete the consumer_output object from the list and free the ptr.
 330  */
 331 void consumer_destroy_output(struct consumer_output *obj)
 332 {
 333         if (obj == NULL) {
 334                 return;
 335         }
 336
 337         if (obj->socks) {
 338                 struct lttng_ht_iter iter;
 339                 struct consumer_socket *socket;
 340
 341                 rcu_read_lock();
 342                 cds_lfht_for_each_entry(obj->socks->ht, &iter.iter, socket, node.node) {
 343                         consumer_del_socket(socket, obj);
 344                         consumer_destroy_socket(socket);
 345                 }
 346                 rcu_read_unlock();
 347
 348                 /* Finally destroy HT */
 349                 lttng_ht_destroy(obj->socks);
 350         }
 351
 352         free(obj);
 353 }
 354
 355 /*
 356  * Copy consumer output and returned the newly allocated copy.
 357  */
 358 struct consumer_output *consumer_copy_output(struct consumer_output *obj)
 359 {
 360         struct lttng_ht *tmp_ht_ptr;
 361         struct lttng_ht_iter iter;
 362         struct consumer_socket *socket, *copy_sock;
 363         struct consumer_output *output;
 364
 365         assert(obj);
 366
 367         output = consumer_create_output(obj->type);
 368         if (output == NULL) {
 369                 goto error;
 370         }
 371         /* Avoid losing the HT reference after the memcpy() */
 372         tmp_ht_ptr = output->socks;
 373
 374         memcpy(output, obj, sizeof(struct consumer_output));
 375
 376         /* Putting back the HT pointer and start copying socket(s). */
 377         output->socks = tmp_ht_ptr;
 378
 379         cds_lfht_for_each_entry(obj->socks->ht, &iter.iter, socket, node.node) {
 380                 /* Create new socket object. */
 381                 copy_sock = consumer_allocate_socket(socket->fd);
 382                 if (copy_sock == NULL) {
 383                         goto malloc_error;
 384                 }
 385
 386                 copy_sock->registered = socket->registered;
 387                 copy_sock->lock = socket->lock;
 388                 consumer_add_socket(copy_sock, output);
 389         }
 390
 391 error:
 392         return output;
 393
 394 malloc_error:
 395         consumer_destroy_output(output);
 396         return NULL;
 397 }
 398
 399 /*
 400  * Set network URI to the consumer output object.
 401  *
 402  * Return 0 on success. Return 1 if the URI were equal. Else, negative value on
 403  * error.
 404  */
 405 int consumer_set_network_uri(struct consumer_output *obj,
 406                 struct lttng_uri *uri)
 407 {
 408         int ret;
 409         char tmp_path[PATH_MAX];
 410         char hostname[HOST_NAME_MAX];
 411         struct lttng_uri *dst_uri = NULL;
 412
 413         /* Code flow error safety net. */
 414         assert(obj);
 415         assert(uri);
 416
 417         switch (uri->stype) {
 418         case LTTNG_STREAM_CONTROL:
 419                 dst_uri = &obj->dst.net.control;
 420                 obj->dst.net.control_isset = 1;
 421                 if (uri->port == 0) {
 422                         /* Assign default port. */
 423                         uri->port = DEFAULT_NETWORK_CONTROL_PORT;
 424                 }
 425                 DBG3("Consumer control URI set with port %d", uri->port);
 426                 break;
 427         case LTTNG_STREAM_DATA:
 428                 dst_uri = &obj->dst.net.data;
 429                 obj->dst.net.data_isset = 1;
 430                 if (uri->port == 0) {
 431                         /* Assign default port. */
 432                         uri->port = DEFAULT_NETWORK_DATA_PORT;
 433                 }
 434                 DBG3("Consumer data URI set with port %d", uri->port);
 435                 break;
 436         default:
 437                 ERR("Set network uri type unknown %d", uri->stype);
 438                 goto error;
 439         }
 440
 441         ret = uri_compare(dst_uri, uri);
 442         if (!ret) {
 443                 /* Same URI, don't touch it and return success. */
 444                 DBG3("URI network compare are the same");
 445                 goto equal;
 446         }
 447
 448         /* URIs were not equal, replacing it. */
 449         memset(dst_uri, 0, sizeof(struct lttng_uri));
 450         memcpy(dst_uri, uri, sizeof(struct lttng_uri));
 451         obj->type = CONSUMER_DST_NET;
 452
 453         /* Handle subdir and add hostname in front. */
 454         if (dst_uri->stype == LTTNG_STREAM_CONTROL) {
 455                 /* Get hostname to append it in the pathname */
 456                 ret = gethostname(hostname, sizeof(hostname));
 457                 if (ret < 0) {
 458                         PERROR("gethostname. Fallback on default localhost");
 459                         strncpy(hostname, "localhost", sizeof(hostname));
 460                 }
 461                 hostname[sizeof(hostname) - 1] = '\0';
 462
 463                 /* Setup consumer subdir if none present in the control URI */
 464                 if (strlen(dst_uri->subdir) == 0) {
 465                         ret = snprintf(tmp_path, sizeof(tmp_path), "%s/%s",
 466                                         hostname, obj->subdir);
 467                 } else {
 468                         ret = snprintf(tmp_path, sizeof(tmp_path), "%s/%s",
 469                                         hostname, dst_uri->subdir);
 470                 }
 471                 if (ret < 0) {
 472                         PERROR("snprintf set consumer uri subdir");
 473                         goto error;
 474                 }
 475
 476                 strncpy(obj->subdir, tmp_path, sizeof(obj->subdir));
 477                 DBG3("Consumer set network uri subdir path %s", tmp_path);
 478         }
 479
 480         return 0;
 481 equal:
 482         return 1;
 483 error:
 484         return -1;
 485 }
 486
 487 /*
 488  * Send file descriptor to consumer via sock.
 489  */
 490 int consumer_send_fds(struct consumer_socket *sock, int *fds, size_t nb_fd)
 491 {
 492         int ret;
 493
 494         assert(fds);
 495         assert(sock);
 496         assert(nb_fd > 0);
 497
 498         ret = lttcomm_send_fds_unix_sock(sock->fd, fds, nb_fd);
 499         if (ret < 0) {
 500                 /* The above call will print a PERROR on error. */
 501                 DBG("Error when sending consumer fds on sock %d", sock->fd);
 502                 goto error;
 503         }
 504
 505         ret = consumer_recv_status_reply(sock);
 506
 507 error:
 508         return ret;
 509 }
 510
 511 /*
 512  * Consumer send channel communication message structure to consumer.
 513  */
 514 int consumer_send_channel(struct consumer_socket *sock,
 515                 struct lttcomm_consumer_msg *msg)
 516 {
 517         int ret;
 518
 519         assert(msg);
 520         assert(sock);
 521         assert(sock->fd >= 0);
 522
 523         ret = lttcomm_send_unix_sock(sock->fd, msg,
 524                         sizeof(struct lttcomm_consumer_msg));
 525         if (ret < 0) {
 526                 /* The above call will print a PERROR on error. */
 527                 DBG("Error when sending consumer channel on sock %d", sock->fd);
 528                 goto error;
 529         }
 530
 531         ret = consumer_recv_status_reply(sock);
 532
 533 error:
 534         return ret;
 535 }
 536
 537 /*
 538  * Init channel communication message structure.
 539  */
 540 void consumer_init_channel_comm_msg(struct lttcomm_consumer_msg *msg,
 541                 enum lttng_consumer_command cmd,
 542                 int channel_key,
 543                 uint64_t max_sb_size,
 544                 uint64_t mmap_len,
 545                 const char *name,
 546                 unsigned int nb_init_streams)
 547 {
 548         assert(msg);
 549
 550         /* TODO: Args validation */
 551
 552         /* Zeroed structure */
 553         memset(msg, 0, sizeof(struct lttcomm_consumer_msg));
 554
 555         /* Send channel */
 556         msg->cmd_type = cmd;
 557         msg->u.channel.channel_key = channel_key;
 558         msg->u.channel.max_sb_size = max_sb_size;
 559         msg->u.channel.mmap_len = mmap_len;
 560         msg->u.channel.nb_init_streams = nb_init_streams;
 561 }
 562
 563 /*
 564  * Init stream communication message structure.
 565  */
 566 void consumer_init_stream_comm_msg(struct lttcomm_consumer_msg *msg,
 567                 enum lttng_consumer_command cmd,
 568                 int channel_key,
 569                 int stream_key,
 570                 uint32_t state,
 571                 enum lttng_event_output output,
 572                 uint64_t mmap_len,
 573                 uid_t uid,
 574                 gid_t gid,
 575                 int net_index,
 576                 unsigned int metadata_flag,
 577                 const char *name,
 578                 const char *pathname,
 579                 unsigned int session_id)
 580 {
 581         assert(msg);
 582
 583         memset(msg, 0, sizeof(struct lttcomm_consumer_msg));
 584
 585         /* TODO: Args validation */
 586
 587         msg->cmd_type = cmd;
 588         msg->u.stream.channel_key = channel_key;
 589         msg->u.stream.stream_key = stream_key;
 590         msg->u.stream.state = state;
 591         msg->u.stream.output = output;
 592         msg->u.stream.mmap_len = mmap_len;
 593         msg->u.stream.uid = uid;
 594         msg->u.stream.gid = gid;
 595         msg->u.stream.net_index = net_index;
 596         msg->u.stream.metadata_flag = metadata_flag;
 597         msg->u.stream.session_id = (uint64_t) session_id;
 598         strncpy(msg->u.stream.name, name, sizeof(msg->u.stream.name));
 599         msg->u.stream.name[sizeof(msg->u.stream.name) - 1] = '\0';
 600         strncpy(msg->u.stream.path_name, pathname,
 601                         sizeof(msg->u.stream.path_name));
 602         msg->u.stream.path_name[sizeof(msg->u.stream.path_name) - 1] = '\0';
 603 }
 604
 605 /*
 606  * Send stream communication structure to the consumer.
 607  */
 608 int consumer_send_stream(struct consumer_socket *sock,
 609                 struct consumer_output *dst, struct lttcomm_consumer_msg *msg,
 610                 int *fds, size_t nb_fd)
 611 {
 612         int ret;
 613
 614         assert(msg);
 615         assert(dst);
 616         assert(sock);
 617
 618         switch (dst->type) {
 619         case CONSUMER_DST_NET:
 620                 /* Consumer should send the stream on the network. */
 621                 msg->u.stream.net_index = dst->net_seq_index;
 622                 break;
 623         case CONSUMER_DST_LOCAL:
 624                 /* Add stream file name to stream path */
 625                 strncat(msg->u.stream.path_name, "/",
 626                                 sizeof(msg->u.stream.path_name) -
 627                                 strlen(msg->u.stream.path_name) - 1);
 628                 strncat(msg->u.stream.path_name, msg->u.stream.name,
 629                                 sizeof(msg->u.stream.path_name) -
 630                                 strlen(msg->u.stream.path_name) - 1);
 631                 msg->u.stream.path_name[sizeof(msg->u.stream.path_name) - 1] = '\0';
 632                 /* Indicate that the stream is NOT network */
 633                 msg->u.stream.net_index = -1;
 634                 break;
 635         default:
 636                 ERR("Consumer unknown output type (%d)", dst->type);
 637                 ret = -1;
 638                 goto error;
 639         }
 640
 641         /* Send on socket */
 642         ret = lttcomm_send_unix_sock(sock->fd, msg,
 643                         sizeof(struct lttcomm_consumer_msg));
 644         if (ret < 0) {
 645                 /* The above call will print a PERROR on error. */
 646                 DBG("Error when sending consumer stream on sock %d", sock->fd);
 647                 goto error;
 648         }
 649
 650         ret = consumer_recv_status_reply(sock);
 651         if (ret < 0) {
 652                 goto error;
 653         }
 654
 655         ret = consumer_send_fds(sock, fds, nb_fd);
 656         if (ret < 0) {
 657                 goto error;
 658         }
 659
 660 error:
 661         return ret;
 662 }
 663
 664 /*
 665  * Send relayd socket to consumer associated with a session name.
 666  *
 667  * On success return positive value. On error, negative value.
 668  */
 669 int consumer_send_relayd_socket(struct consumer_socket *consumer_sock,
 670                 struct lttcomm_sock *sock, struct consumer_output *consumer,
 671                 enum lttng_stream_type type, unsigned int session_id)
 672 {
 673         int ret;
 674         struct lttcomm_consumer_msg msg;
 675
 676         /* Code flow error. Safety net. */
 677         assert(sock);
 678         assert(consumer);
 679         assert(consumer_sock);
 680
 681         /* Bail out if consumer is disabled */
 682         if (!consumer->enabled) {
 683                 ret = LTTNG_OK;
 684                 goto error;
 685         }
 686
 687         msg.cmd_type = LTTNG_CONSUMER_ADD_RELAYD_SOCKET;
 688         /*
 689          * Assign network consumer output index using the temporary consumer since
 690          * this call should only be made from within a set_consumer_uri() function
 691          * call in the session daemon.
 692          */
 693         msg.u.relayd_sock.net_index = consumer->net_seq_index;
 694         msg.u.relayd_sock.type = type;
 695         msg.u.relayd_sock.session_id = session_id;
 696         memcpy(&msg.u.relayd_sock.sock, sock, sizeof(msg.u.relayd_sock.sock));
 697
 698         DBG3("Sending relayd sock info to consumer on %d", consumer_sock->fd);
 699         ret = lttcomm_send_unix_sock(consumer_sock->fd, &msg, sizeof(msg));
 700         if (ret < 0) {
 701                 /* The above call will print a PERROR on error. */
 702                 DBG("Error when sending relayd sockets on sock %d", sock->fd);
 703                 goto error;
 704         }
 705
 706         ret = consumer_recv_status_reply(consumer_sock);
 707         if (ret < 0) {
 708                 goto error;
 709         }
 710
 711         DBG3("Sending relayd socket file descriptor to consumer");
 712         ret = consumer_send_fds(consumer_sock, &sock->fd, 1);
 713         if (ret < 0) {
 714                 goto error;
 715         }
 716
 717         DBG2("Consumer relayd socket sent");
 718
 719 error:
 720         return ret;
 721 }
 722
 723 /*
 724  * Set consumer subdirectory using the session name and a generated datetime if
 725  * needed. This is appended to the current subdirectory.
 726  */
 727 int consumer_set_subdir(struct consumer_output *consumer,
 728                 const char *session_name)
 729 {
 730         int ret = 0;
 731         unsigned int have_default_name = 0;
 732         char datetime[16], tmp_path[PATH_MAX];
 733         time_t rawtime;
 734         struct tm *timeinfo;
 735
 736         assert(consumer);
 737         assert(session_name);
 738
 739         memset(tmp_path, 0, sizeof(tmp_path));
 740
 741         /* Flag if we have a default session. */
 742         if (strncmp(session_name, DEFAULT_SESSION_NAME "-",
 743                                 strlen(DEFAULT_SESSION_NAME) + 1) == 0) {
 744                 have_default_name = 1;
 745         } else {
 746                 /* Get date and time for session path */
 747                 time(&rawtime);
 748                 timeinfo = localtime(&rawtime);
 749                 strftime(datetime, sizeof(datetime), "%Y%m%d-%H%M%S", timeinfo);
 750         }
 751
 752         if (have_default_name) {
 753                 ret = snprintf(tmp_path, sizeof(tmp_path),
 754                                 "%s/%s", consumer->subdir, session_name);
 755         } else {
 756                 ret = snprintf(tmp_path, sizeof(tmp_path),
 757                                 "%s/%s-%s/", consumer->subdir, session_name, datetime);
 758         }
 759         if (ret < 0) {
 760                 PERROR("snprintf session name date");
 761                 goto error;
 762         }
 763
 764         strncpy(consumer->subdir, tmp_path, sizeof(consumer->subdir));
 765         DBG2("Consumer subdir set to %s", consumer->subdir);
 766
 767 error:
 768         return ret;
 769 }
 770
 771 /*
 772  * Ask the consumer if the data is ready to read (NOT pending) for the specific
 773  * session id.
 774  *
 775  * This function has a different behavior with the consumer i.e. that it waits
 776  * for a reply from the consumer if yes or no the data is pending.
 777  */
 778 int consumer_is_data_pending(unsigned int id,
 779                 struct consumer_output *consumer)
 780 {
 781         int ret;
 782         int32_t ret_code = 0;  /* Default is that the data is NOT pending */
 783         struct consumer_socket *socket;
 784         struct lttng_ht_iter iter;
 785         struct lttcomm_consumer_msg msg;
 786
 787         assert(consumer);
 788
 789         msg.cmd_type = LTTNG_CONSUMER_DATA_PENDING;
 790
 791         msg.u.data_pending.session_id = (uint64_t) id;
 792
 793         DBG3("Consumer data pending for id %u", id);
 794
 795         /* Send command for each consumer */
 796         cds_lfht_for_each_entry(consumer->socks->ht, &iter.iter, socket,
 797                         node.node) {
 798                 /* Code flow error */
 799                 assert(socket->fd >= 0);
 800
 801                 pthread_mutex_lock(socket->lock);
 802
 803                 ret = lttcomm_send_unix_sock(socket->fd, &msg, sizeof(msg));
 804                 if (ret < 0) {
 805                         /* The above call will print a PERROR on error. */
 806                         DBG("Error on consumer is data pending on sock %d", socket->fd);
 807                         pthread_mutex_unlock(socket->lock);
 808                         goto error;
 809                 }
 810
 811                 /*
 812                  * No need for a recv reply status because the answer to the command is
 813                  * the reply status message.
 814                  */
 815
 816                 ret = lttcomm_recv_unix_sock(socket->fd, &ret_code, sizeof(ret_code));
 817                 if (ret <= 0) {
 818                         if (ret == 0) {
 819                                 /* Orderly shutdown. Don't return 0 which means success. */
 820                                 ret = -1;
 821                         }
 822                         /* The above call will print a PERROR on error. */
 823                         DBG("Error on recv consumer is data pending on sock %d", socket->fd);
 824                         pthread_mutex_unlock(socket->lock);
 825                         goto error;
 826                 }
 827
 828                 pthread_mutex_unlock(socket->lock);
 829
 830                 if (ret_code == 1) {
 831                         break;
 832                 }
 833         }
 834
 835         DBG("Consumer data is %s pending for session id %u",
 836                         ret_code == 1 ? "" : "NOT", id);
 837         return ret_code;
 838
 839 error:
 840         return -1;
 841 }