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