src/bin/lttng-sessiond/ust-consumer.c

   1 /*
   2  * Copyright (C) 2011 - David Goulet <david.goulet@polymtl.ca>
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License, version 2 only,
   6  * as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11  * GNU General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public License along
  14  * with this program; if not, write to the Free Software Foundation, Inc.,
  15  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  16  */
  17
  18 #define _LGPL_SOURCE
  19 #include <errno.h>
  20 #include <stdio.h>
  21 #include <stdlib.h>
  22 #include <string.h>
  23 #include <unistd.h>
  24 #include <inttypes.h>
  25
  26 #include <common/common.h>
  27 #include <common/consumer/consumer.h>
  28 #include <common/defaults.h>
  29
  30 #include "consumer.h"
  31 #include "health-sessiond.h"
  32 #include "ust-consumer.h"
  33 #include "buffer-registry.h"
  34 #include "session.h"
  35
  36 /*
  37  * Return allocated full pathname of the session using the consumer trace path
  38  * and subdir if available. On a successful allocation, the directory of the
  39  * trace is created with the session credentials.
  40  *
  41  * The caller can safely free(3) the returned value. On error, NULL is
  42  * returned.
  43  */
  44 static char *setup_trace_path(struct consumer_output *consumer,
  45                 struct ust_app_session *ua_sess)
  46 {
  47         int ret;
  48         char *pathname;
  49
  50         assert(consumer);
  51         assert(ua_sess);
  52
  53         health_code_update();
  54
  55         /* Allocate our self the string to make sure we never exceed PATH_MAX. */
  56         pathname = zmalloc(PATH_MAX);
  57         if (!pathname) {
  58                 goto error;
  59         }
  60
  61         /* Get correct path name destination */
  62         if (consumer->type == CONSUMER_DST_LOCAL) {
  63                 /* Set application path to the destination path */
  64                 ret = snprintf(pathname, PATH_MAX, "%s%s%s",
  65                                 consumer->dst.trace_path, consumer->subdir, ua_sess->path);
  66                 if (ret < 0) {
  67                         PERROR("snprintf channel path");
  68                         goto error;
  69                 }
  70
  71                 /* Create directory. Ignore if exist. */
  72                 ret = run_as_mkdir_recursive(pathname, S_IRWXU | S_IRWXG,
  73                                 ua_sess->euid, ua_sess->egid);
  74                 if (ret < 0) {
  75                         if (errno != EEXIST) {
  76                                 ERR("Trace directory creation error");
  77                                 goto error;
  78                         }
  79                 }
  80         } else {
  81                 ret = snprintf(pathname, PATH_MAX, "%s%s", consumer->subdir,
  82                                 ua_sess->path);
  83                 if (ret < 0) {
  84                         PERROR("snprintf channel path");
  85                         goto error;
  86                 }
  87         }
  88
  89         return pathname;
  90
  91 error:
  92         free(pathname);
  93         return NULL;
  94 }
  95
  96 /*
  97  * Send a single channel to the consumer using command ADD_CHANNEL.
  98  *
  99  * Consumer socket lock MUST be acquired before calling this.
 100  */
 101 static int ask_channel_creation(struct ust_app_session *ua_sess,
 102                 struct ust_app_channel *ua_chan, struct consumer_output *consumer,
 103                 struct consumer_socket *socket, struct ust_registry_session *registry)
 104 {
 105         int ret, output;
 106         uint32_t chan_id;
 107         uint64_t key, chan_reg_key;
 108         char *pathname = NULL;
 109         struct lttcomm_consumer_msg msg;
 110         struct ust_registry_channel *chan_reg;
 111         char shm_path[PATH_MAX] = "";
 112         char root_shm_path[PATH_MAX] = "";
 113
 114         assert(ua_sess);
 115         assert(ua_chan);
 116         assert(socket);
 117         assert(consumer);
 118         assert(registry);
 119
 120         DBG2("Asking UST consumer for channel");
 121
 122         /* Get and create full trace path of session. */
 123         if (ua_sess->output_traces) {
 124                 pathname = setup_trace_path(consumer, ua_sess);
 125                 if (!pathname) {
 126                         ret = -1;
 127                         goto error;
 128                 }
 129         }
 130
 131         /* Depending on the buffer type, a different channel key is used. */
 132         if (ua_sess->buffer_type == LTTNG_BUFFER_PER_UID) {
 133                 chan_reg_key = ua_chan->tracing_channel_id;
 134         } else {
 135                 chan_reg_key = ua_chan->key;
 136         }
 137
 138         if (ua_chan->attr.type == LTTNG_UST_CHAN_METADATA) {
 139                 chan_id = -1U;
 140                 /*
 141                  * Metadata channels shm_path (buffers) are handled within
 142                  * session daemon. Consumer daemon should not try to create
 143                  * those buffer files.
 144                  */
 145         } else {
 146                 chan_reg = ust_registry_channel_find(registry, chan_reg_key);
 147                 assert(chan_reg);
 148                 chan_id = chan_reg->chan_id;
 149                 if (ua_sess->shm_path[0]) {
 150                         strncpy(shm_path, ua_sess->shm_path, sizeof(shm_path));
 151                         shm_path[sizeof(shm_path) - 1] = '\0';
 152                         strncat(shm_path, "/",
 153                                 sizeof(shm_path) - strlen(shm_path) - 1);
 154                         strncat(shm_path, ua_chan->name,
 155                                         sizeof(shm_path) - strlen(shm_path) - 1);
 156                                 strncat(shm_path, "_",
 157                                         sizeof(shm_path) - strlen(shm_path) - 1);
 158                 }
 159                 strncpy(root_shm_path, ua_sess->root_shm_path, sizeof(root_shm_path));
 160                 root_shm_path[sizeof(root_shm_path) - 1] = '\0';
 161         }
 162
 163         switch (ua_chan->attr.output) {
 164         case LTTNG_UST_MMAP:
 165         default:
 166                 output = LTTNG_EVENT_MMAP;
 167                 break;
 168         }
 169
 170         consumer_init_ask_channel_comm_msg(&msg,
 171                         ua_chan->attr.subbuf_size,
 172                         ua_chan->attr.num_subbuf,
 173                         ua_chan->attr.overwrite,
 174                         ua_chan->attr.switch_timer_interval,
 175                         ua_chan->attr.read_timer_interval,
 176                         ua_sess->live_timer_interval,
 177                         ua_sess->live_timer_interval != 0,
 178                         output,
 179                         (int) ua_chan->attr.type,
 180                         ua_sess->tracing_id,
 181                         pathname,
 182                         ua_chan->name,
 183                         ua_sess->euid,
 184                         ua_sess->egid,
 185                         consumer->net_seq_index,
 186                         ua_chan->key,
 187                         registry->uuid,
 188                         chan_id,
 189                         ua_chan->tracefile_size,
 190                         ua_chan->tracefile_count,
 191                         ua_sess->id,
 192                         ua_sess->output_traces,
 193                         ua_sess->uid,
 194                         root_shm_path, shm_path);
 195
 196         health_code_update();
 197
 198         ret = consumer_socket_send(socket, &msg, sizeof(msg));
 199         if (ret < 0) {
 200                 goto error;
 201         }
 202
 203         ret = consumer_recv_status_channel(socket, &key,
 204                         &ua_chan->expected_stream_count);
 205         if (ret < 0) {
 206                 goto error;
 207         }
 208         /* Communication protocol error. */
 209         assert(key == ua_chan->key);
 210         /* We need at least one where 1 stream for 1 cpu. */
 211         if (ua_sess->output_traces) {
 212                 assert(ua_chan->expected_stream_count > 0);
 213         }
 214
 215         DBG2("UST ask channel %" PRIu64 " successfully done with %u stream(s)", key,
 216                         ua_chan->expected_stream_count);
 217
 218 error:
 219         free(pathname);
 220         health_code_update();
 221         return ret;
 222 }
 223
 224 /*
 225  * Ask consumer to create a channel for a given session.
 226  *
 227  * Returns 0 on success else a negative value.
 228  */
 229 int ust_consumer_ask_channel(struct ust_app_session *ua_sess,
 230                 struct ust_app_channel *ua_chan, struct consumer_output *consumer,
 231                 struct consumer_socket *socket, struct ust_registry_session *registry)
 232 {
 233         int ret;
 234
 235         assert(ua_sess);
 236         assert(ua_chan);
 237         assert(consumer);
 238         assert(socket);
 239         assert(registry);
 240
 241         if (!consumer->enabled) {
 242                 ret = -LTTNG_ERR_NO_CONSUMER;
 243                 DBG3("Consumer is disabled");
 244                 goto error;
 245         }
 246
 247         pthread_mutex_lock(socket->lock);
 248         ret = ask_channel_creation(ua_sess, ua_chan, consumer, socket, registry);
 249         pthread_mutex_unlock(socket->lock);
 250         if (ret < 0) {
 251                 goto error;
 252         }
 253
 254 error:
 255         return ret;
 256 }
 257
 258 /*
 259  * Send a get channel command to consumer using the given channel key.  The
 260  * channel object is populated and the stream list.
 261  *
 262  * Return 0 on success else a negative value.
 263  */
 264 int ust_consumer_get_channel(struct consumer_socket *socket,
 265                 struct ust_app_channel *ua_chan)
 266 {
 267         int ret;
 268         struct lttcomm_consumer_msg msg;
 269
 270         assert(ua_chan);
 271         assert(socket);
 272
 273         memset(&msg, 0, sizeof(msg));
 274         msg.cmd_type = LTTNG_CONSUMER_GET_CHANNEL;
 275         msg.u.get_channel.key = ua_chan->key;
 276
 277         pthread_mutex_lock(socket->lock);
 278         health_code_update();
 279
 280         /* Send command and wait for OK reply. */
 281         ret = consumer_send_msg(socket, &msg);
 282         if (ret < 0) {
 283                 goto error;
 284         }
 285
 286         /* First, get the channel from consumer. */
 287         ret = ustctl_recv_channel_from_consumer(*socket->fd_ptr, &ua_chan->obj);
 288         if (ret < 0) {
 289                 if (ret != -EPIPE) {
 290                         ERR("Error recv channel from consumer %d with ret %d",
 291                                         *socket->fd_ptr, ret);
 292                 } else {
 293                         DBG3("UST app recv channel from consumer. Consumer is dead.");
 294                 }
 295                 goto error;
 296         }
 297
 298         /* Next, get all streams. */
 299         while (1) {
 300                 struct ust_app_stream *stream;
 301
 302                 /* Create UST stream */
 303                 stream = ust_app_alloc_stream();
 304                 if (stream == NULL) {
 305                         ret = -ENOMEM;
 306                         goto error;
 307                 }
 308
 309                 /* Stream object is populated by this call if successful. */
 310                 ret = ustctl_recv_stream_from_consumer(*socket->fd_ptr, &stream->obj);
 311                 if (ret < 0) {
 312                         free(stream);
 313                         if (ret == -LTTNG_UST_ERR_NOENT) {
 314                                 DBG3("UST app consumer has no more stream available");
 315                                 ret = 0;
 316                                 break;
 317                         }
 318                         if (ret != -EPIPE) {
 319                                 ERR("Recv stream from consumer %d with ret %d",
 320                                                 *socket->fd_ptr, ret);
 321                         } else {
 322                                 DBG3("UST app recv stream from consumer. Consumer is dead.");
 323                         }
 324                         goto error;
 325                 }
 326
 327                 /* Order is important this is why a list is used. */
 328                 cds_list_add_tail(&stream->list, &ua_chan->streams.head);
 329                 ua_chan->streams.count++;
 330
 331                 DBG2("UST app stream %d received successfully", ua_chan->streams.count);
 332         }
 333
 334         /* This MUST match or else we have a synchronization problem. */
 335         assert(ua_chan->expected_stream_count == ua_chan->streams.count);
 336
 337         /* Wait for confirmation that we can proceed with the streams. */
 338         ret = consumer_recv_status_reply(socket);
 339         if (ret < 0) {
 340                 goto error;
 341         }
 342
 343 error:
 344         health_code_update();
 345         pthread_mutex_unlock(socket->lock);
 346         return ret;
 347 }
 348
 349 /*
 350  * Send a destroy channel command to consumer using the given channel key.
 351  *
 352  * Note that this command MUST be used prior to a successful
 353  * LTTNG_CONSUMER_GET_CHANNEL because once this command is done successfully,
 354  * the streams are dispatched to the consumer threads and MUST be teardown
 355  * through the hang up process.
 356  *
 357  * Return 0 on success else a negative value.
 358  */
 359 int ust_consumer_destroy_channel(struct consumer_socket *socket,
 360                 struct ust_app_channel *ua_chan)
 361 {
 362         int ret;
 363         struct lttcomm_consumer_msg msg;
 364
 365         assert(ua_chan);
 366         assert(socket);
 367
 368         memset(&msg, 0, sizeof(msg));
 369         msg.cmd_type = LTTNG_CONSUMER_DESTROY_CHANNEL;
 370         msg.u.destroy_channel.key = ua_chan->key;
 371
 372         pthread_mutex_lock(socket->lock);
 373         health_code_update();
 374
 375         ret = consumer_send_msg(socket, &msg);
 376         if (ret < 0) {
 377                 goto error;
 378         }
 379
 380 error:
 381         health_code_update();
 382         pthread_mutex_unlock(socket->lock);
 383         return ret;
 384 }
 385
 386 /*
 387  * Send a given stream to UST tracer.
 388  *
 389  * On success return 0 else a negative value.
 390  */
 391 int ust_consumer_send_stream_to_ust(struct ust_app *app,
 392                 struct ust_app_channel *channel, struct ust_app_stream *stream)
 393 {
 394         int ret;
 395
 396         assert(app);
 397         assert(stream);
 398         assert(channel);
 399
 400         DBG2("UST consumer send stream to app %d", app->sock);
 401
 402         /* Relay stream to application. */
 403         pthread_mutex_lock(&app->sock_lock);
 404         ret = ustctl_send_stream_to_ust(app->sock, channel->obj, stream->obj);
 405         pthread_mutex_unlock(&app->sock_lock);
 406         if (ret < 0) {
 407                 if (ret != -EPIPE && ret != -LTTNG_UST_ERR_EXITING) {
 408                         ERR("ustctl send stream handle %d to app pid: %d with ret %d",
 409                                         stream->obj->handle, app->pid, ret);
 410                 } else {
 411                         DBG3("UST app send stream to ust failed. Application is dead.");
 412                 }
 413                 goto error;
 414         }
 415         channel->handle = channel->obj->handle;
 416
 417 error:
 418         return ret;
 419 }
 420
 421 /*
 422  * Send channel previously received from the consumer to the UST tracer.
 423  *
 424  * On success return 0 else a negative value.
 425  */
 426 int ust_consumer_send_channel_to_ust(struct ust_app *app,
 427                 struct ust_app_session *ua_sess, struct ust_app_channel *channel)
 428 {
 429         int ret;
 430
 431         assert(app);
 432         assert(ua_sess);
 433         assert(channel);
 434         assert(channel->obj);
 435
 436         DBG2("UST app send channel to sock %d pid %d (name: %s, key: %" PRIu64 ")",
 437                         app->sock, app->pid, channel->name, channel->tracing_channel_id);
 438
 439         /* Send stream to application. */
 440         pthread_mutex_lock(&app->sock_lock);
 441         ret = ustctl_send_channel_to_ust(app->sock, ua_sess->handle, channel->obj);
 442         pthread_mutex_unlock(&app->sock_lock);
 443         if (ret < 0) {
 444                 if (ret != -EPIPE && ret != -LTTNG_UST_ERR_EXITING) {
 445                         ERR("Error ustctl send channel %s to app pid: %d with ret %d",
 446                                         channel->name, app->pid, ret);
 447                 } else {
 448                         DBG3("UST app send channel to ust failed. Application is dead.");
 449                 }
 450                 goto error;
 451         }
 452
 453 error:
 454         return ret;
 455 }
 456
 457 /*
 458  * Handle the metadata requests from the UST consumer
 459  *
 460  * Return 0 on success else a negative value.
 461  */
 462 int ust_consumer_metadata_request(struct consumer_socket *socket)
 463 {
 464         int ret;
 465         ssize_t ret_push;
 466         struct lttcomm_metadata_request_msg request;
 467         struct buffer_reg_uid *reg_uid;
 468         struct ust_registry_session *ust_reg;
 469         struct lttcomm_consumer_msg msg;
 470
 471         assert(socket);
 472
 473         rcu_read_lock();
 474         health_code_update();
 475
 476         /* Wait for a metadata request */
 477         pthread_mutex_lock(socket->lock);
 478         ret = consumer_socket_recv(socket, &request, sizeof(request));
 479         pthread_mutex_unlock(socket->lock);
 480         if (ret < 0) {
 481                 goto end;
 482         }
 483
 484         DBG("Metadata request received for session %" PRIu64 ", key %" PRIu64,
 485                         request.session_id, request.key);
 486
 487         reg_uid = buffer_reg_uid_find(request.session_id,
 488                         request.bits_per_long, request.uid);
 489         if (reg_uid) {
 490                 ust_reg = reg_uid->registry->reg.ust;
 491         } else {
 492                 struct buffer_reg_pid *reg_pid =
 493                         buffer_reg_pid_find(request.session_id_per_pid);
 494                 if (!reg_pid) {
 495                         DBG("PID registry not found for session id %" PRIu64,
 496                                         request.session_id_per_pid);
 497
 498                         memset(&msg, 0, sizeof(msg));
 499                         msg.cmd_type = LTTNG_ERR_UND;
 500                         pthread_mutex_lock(socket->lock);
 501                         (void) consumer_send_msg(socket, &msg);
 502                         pthread_mutex_unlock(socket->lock);
 503                         /*
 504                          * This is possible since the session might have been destroyed
 505                          * during a consumer metadata request. So here, return gracefully
 506                          * because the destroy session will push the remaining metadata to
 507                          * the consumer.
 508                          */
 509                         ret = 0;
 510                         goto end;
 511                 }
 512                 ust_reg = reg_pid->registry->reg.ust;
 513         }
 514         assert(ust_reg);
 515
 516         pthread_mutex_lock(&ust_reg->lock);
 517         ret_push = ust_app_push_metadata(ust_reg, socket, 1);
 518         pthread_mutex_unlock(&ust_reg->lock);
 519         if (ret_push == -EPIPE) {
 520                 DBG("Application or relay closed while pushing metadata");
 521         } else if (ret_push < 0) {
 522                 ERR("Pushing metadata");
 523                 ret = -1;
 524                 goto end;
 525         } else {
 526                 DBG("UST Consumer metadata pushed successfully");
 527         }
 528         ret = 0;
 529
 530 end:
 531         rcu_read_unlock();
 532         return ret;
 533 }