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 #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.h>
  28 #include <common/defaults.h>
  29
  30 #include "consumer.h"
  31 #include "health.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 (ret != -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;
 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
 112         assert(ua_sess);
 113         assert(ua_chan);
 114         assert(socket);
 115         assert(consumer);
 116         assert(registry);
 117
 118         DBG2("Asking UST consumer for channel");
 119
 120         /* Get and create full trace path of session. */
 121         if (ua_sess->output_traces) {
 122                 pathname = setup_trace_path(consumer, ua_sess);
 123                 if (!pathname) {
 124                         ret = -1;
 125                         goto error;
 126                 }
 127         }
 128
 129         /* Depending on the buffer type, a different channel key is used. */
 130         if (ua_sess->buffer_type == LTTNG_BUFFER_PER_UID) {
 131                 chan_reg_key = ua_chan->tracing_channel_id;
 132         } else {
 133                 chan_reg_key = ua_chan->key;
 134         }
 135
 136         if (ua_chan->attr.type == LTTNG_UST_CHAN_METADATA) {
 137                 chan_id = -1U;
 138         } else {
 139                 chan_reg = ust_registry_channel_find(registry, chan_reg_key);
 140                 assert(chan_reg);
 141                 chan_id = chan_reg->chan_id;
 142         }
 143
 144         consumer_init_ask_channel_comm_msg(&msg,
 145                         ua_chan->attr.subbuf_size,
 146                         ua_chan->attr.num_subbuf,
 147                         ua_chan->attr.overwrite,
 148                         ua_chan->attr.switch_timer_interval,
 149                         ua_chan->attr.read_timer_interval,
 150                         (int) ua_chan->attr.output,
 151                         (int) ua_chan->attr.type,
 152                         ua_sess->tracing_id,
 153                         pathname,
 154                         ua_chan->name,
 155                         ua_sess->euid,
 156                         ua_sess->egid,
 157                         consumer->net_seq_index,
 158                         ua_chan->key,
 159                         registry->uuid,
 160                         chan_id,
 161                         ua_chan->tracefile_size,
 162                         ua_chan->tracefile_count,
 163                         ua_sess->id,
 164                         ua_sess->output_traces);
 165
 166         health_code_update();
 167
 168         ret = lttcomm_send_unix_sock(socket->fd, &msg, sizeof(msg));
 169         if (ret < 0) {
 170                 goto error;
 171         }
 172
 173         ret = consumer_recv_status_channel(socket, &key,
 174                         &ua_chan->expected_stream_count);
 175         if (ret < 0) {
 176                 goto error;
 177         }
 178         /* Communication protocol error. */
 179         assert(key == ua_chan->key);
 180         /* We need at least one where 1 stream for 1 cpu. */
 181         if (ua_sess->output_traces) {
 182                 assert(ua_chan->expected_stream_count > 0);
 183         }
 184
 185         DBG2("UST ask channel %" PRIu64 " successfully done with %u stream(s)", key,
 186                         ua_chan->expected_stream_count);
 187
 188 error:
 189         free(pathname);
 190         health_code_update();
 191         return ret;
 192 }
 193
 194 /*
 195  * Ask consumer to create a channel for a given session.
 196  *
 197  * Returns 0 on success else a negative value.
 198  */
 199 int ust_consumer_ask_channel(struct ust_app_session *ua_sess,
 200                 struct ust_app_channel *ua_chan, struct consumer_output *consumer,
 201                 struct consumer_socket *socket, struct ust_registry_session *registry)
 202 {
 203         int ret;
 204
 205         assert(ua_sess);
 206         assert(ua_chan);
 207         assert(consumer);
 208         assert(socket);
 209         assert(socket->fd >= 0);
 210         assert(registry);
 211
 212         if (!consumer->enabled) {
 213                 ret = -LTTNG_ERR_NO_CONSUMER;
 214                 DBG3("Consumer is disabled");
 215                 goto error;
 216         }
 217
 218         pthread_mutex_lock(socket->lock);
 219
 220         ret = ask_channel_creation(ua_sess, ua_chan, consumer, socket, registry);
 221         if (ret < 0) {
 222                 goto error;
 223         }
 224
 225 error:
 226         pthread_mutex_unlock(socket->lock);
 227         return ret;
 228 }
 229
 230 /*
 231  * Send a get channel command to consumer using the given channel key.  The
 232  * channel object is populated and the stream list.
 233  *
 234  * Return 0 on success else a negative value.
 235  */
 236 int ust_consumer_get_channel(struct consumer_socket *socket,
 237                 struct ust_app_channel *ua_chan)
 238 {
 239         int ret;
 240         struct lttcomm_consumer_msg msg;
 241
 242         assert(ua_chan);
 243         assert(socket);
 244         assert(socket->fd >= 0);
 245
 246         msg.cmd_type = LTTNG_CONSUMER_GET_CHANNEL;
 247         msg.u.get_channel.key = ua_chan->key;
 248
 249         pthread_mutex_lock(socket->lock);
 250         health_code_update();
 251
 252         /* Send command and wait for OK reply. */
 253         ret = consumer_send_msg(socket, &msg);
 254         if (ret < 0) {
 255                 goto error;
 256         }
 257
 258         /* First, get the channel from consumer. */
 259         ret = ustctl_recv_channel_from_consumer(socket->fd, &ua_chan->obj);
 260         if (ret < 0) {
 261                 if (ret != -EPIPE) {
 262                         ERR("Error recv channel from consumer %d with ret %d",
 263                                         socket->fd, ret);
 264                 } else {
 265                         DBG3("UST app recv channel from consumer. Consumer is dead.");
 266                 }
 267                 goto error;
 268         }
 269
 270         /* Next, get all streams. */
 271         while (1) {
 272                 struct ust_app_stream *stream;
 273
 274                 /* Create UST stream */
 275                 stream = ust_app_alloc_stream();
 276                 if (stream == NULL) {
 277                         ret = -ENOMEM;
 278                         goto error;
 279                 }
 280
 281                 /* Stream object is populated by this call if successful. */
 282                 ret = ustctl_recv_stream_from_consumer(socket->fd, &stream->obj);
 283                 if (ret < 0) {
 284                         free(stream);
 285                         if (ret == -LTTNG_UST_ERR_NOENT) {
 286                                 DBG3("UST app consumer has no more stream available");
 287                                 ret = 0;
 288                                 break;
 289                         }
 290                         if (ret != -EPIPE) {
 291                                 ERR("Recv stream from consumer %d with ret %d",
 292                                                 socket->fd, ret);
 293                         } else {
 294                                 DBG3("UST app recv stream from consumer. Consumer is dead.");
 295                         }
 296                         goto error;
 297                 }
 298
 299                 /* Order is important this is why a list is used. */
 300                 cds_list_add_tail(&stream->list, &ua_chan->streams.head);
 301                 ua_chan->streams.count++;
 302
 303                 DBG2("UST app stream %d received succesfully", ua_chan->streams.count);
 304         }
 305
 306         /* This MUST match or else we have a synchronization problem. */
 307         assert(ua_chan->expected_stream_count == ua_chan->streams.count);
 308
 309         /* Wait for confirmation that we can proceed with the streams. */
 310         ret = consumer_recv_status_reply(socket);
 311         if (ret < 0) {
 312                 goto error;
 313         }
 314
 315 error:
 316         health_code_update();
 317         pthread_mutex_unlock(socket->lock);
 318         return ret;
 319 }
 320
 321 /*
 322  * Send a destroy channel command to consumer using the given channel key.
 323  *
 324  * Note that this command MUST be used prior to a successful
 325  * LTTNG_CONSUMER_GET_CHANNEL because once this command is done successfully,
 326  * the streams are dispatched to the consumer threads and MUST be teardown
 327  * through the hang up process.
 328  *
 329  * Return 0 on success else a negative value.
 330  */
 331 int ust_consumer_destroy_channel(struct consumer_socket *socket,
 332                 struct ust_app_channel *ua_chan)
 333 {
 334         int ret;
 335         struct lttcomm_consumer_msg msg;
 336
 337         assert(ua_chan);
 338         assert(socket);
 339         assert(socket->fd >= 0);
 340
 341         msg.cmd_type = LTTNG_CONSUMER_DESTROY_CHANNEL;
 342         msg.u.destroy_channel.key = ua_chan->key;
 343
 344         pthread_mutex_lock(socket->lock);
 345         health_code_update();
 346
 347         ret = consumer_send_msg(socket, &msg);
 348         if (ret < 0) {
 349                 goto error;
 350         }
 351
 352 error:
 353         health_code_update();
 354         pthread_mutex_unlock(socket->lock);
 355         return ret;
 356 }
 357
 358 /*
 359  * Send a given stream to UST tracer.
 360  *
 361  * On success return 0 else a negative value.
 362  */
 363 int ust_consumer_send_stream_to_ust(struct ust_app *app,
 364                 struct ust_app_channel *channel, struct ust_app_stream *stream)
 365 {
 366         int ret;
 367
 368         assert(app);
 369         assert(stream);
 370         assert(channel);
 371
 372         DBG2("UST consumer send stream to app %d", app->sock);
 373
 374         /* Relay stream to application. */
 375         ret = ustctl_send_stream_to_ust(app->sock, channel->obj, stream->obj);
 376         if (ret < 0) {
 377                 if (ret != -EPIPE && ret != -LTTNG_UST_ERR_EXITING) {
 378                         ERR("Error ustctl send stream %s to app pid: %d with ret %d",
 379                                         stream->name, app->pid, ret);
 380                 } else {
 381                         DBG3("UST app send stream to ust failed. Application is dead.");
 382                 }
 383                 goto error;
 384         }
 385         channel->handle = channel->obj->handle;
 386
 387 error:
 388         return ret;
 389 }
 390
 391 /*
 392  * Send channel previously received from the consumer to the UST tracer.
 393  *
 394  * On success return 0 else a negative value.
 395  */
 396 int ust_consumer_send_channel_to_ust(struct ust_app *app,
 397                 struct ust_app_session *ua_sess, struct ust_app_channel *channel)
 398 {
 399         int ret;
 400
 401         assert(app);
 402         assert(ua_sess);
 403         assert(channel);
 404         assert(channel->obj);
 405
 406         DBG2("UST app send channel to sock %d pid %d (name: %s, key: %" PRIu64 ")",
 407                         app->sock, app->pid, channel->name, channel->tracing_channel_id);
 408
 409         /* Send stream to application. */
 410         ret = ustctl_send_channel_to_ust(app->sock, ua_sess->handle, channel->obj);
 411         if (ret < 0) {
 412                 if (ret != -EPIPE && ret != -LTTNG_UST_ERR_EXITING) {
 413                         ERR("Error ustctl send channel %s to app pid: %d with ret %d",
 414                                         channel->name, app->pid, ret);
 415                 } else {
 416                         DBG3("UST app send channel to ust failed. Application is dead.");
 417                 }
 418                 goto error;
 419         }
 420
 421 error:
 422         return ret;
 423 }
 424
 425 /*
 426  * Handle the metadata requests from the UST consumer
 427  *
 428  * Return 0 on success else a negative value.
 429  */
 430 int ust_consumer_metadata_request(struct consumer_socket *socket)
 431 {
 432         int ret;
 433         ssize_t ret_push;
 434         struct lttcomm_metadata_request_msg request;
 435         struct buffer_reg_uid *reg_uid;
 436         struct ust_registry_session *ust_reg;
 437         struct lttcomm_consumer_msg msg;
 438
 439         assert(socket);
 440
 441         rcu_read_lock();
 442         pthread_mutex_lock(socket->lock);
 443
 444         health_code_update();
 445
 446         /* Wait for a metadata request */
 447         ret = lttcomm_recv_unix_sock(socket->fd, &request, sizeof(request));
 448         if (ret <= 0) {
 449                 ERR("Consumer closed the metadata socket");
 450                 ret = -1;
 451                 goto end;
 452         }
 453
 454         DBG("Metadata request received for session %" PRIu64 ", key %" PRIu64,
 455                         request.session_id, request.key);
 456
 457         reg_uid = buffer_reg_uid_find(request.session_id,
 458                         request.bits_per_long, request.uid);
 459         if (reg_uid) {
 460                 ust_reg = reg_uid->registry->reg.ust;
 461         } else {
 462                 struct buffer_reg_pid *reg_pid =
 463                         buffer_reg_pid_find(request.session_id_per_pid);
 464                 if (!reg_pid) {
 465                         DBG("PID registry not found for session id %" PRIu64,
 466                                         request.session_id_per_pid);
 467
 468                         msg.cmd_type = LTTNG_ERR_UND;
 469                         (void) consumer_send_msg(socket, &msg);
 470                         /*
 471                          * This is possible since the session might have been destroyed
 472                          * during a consumer metadata request. So here, return gracefully
 473                          * because the destroy session will push the remaining metadata to
 474                          * the consumer.
 475                          */
 476                         ret = 0;
 477                         goto end;
 478                 }
 479                 ust_reg = reg_pid->registry->reg.ust;
 480         }
 481         assert(ust_reg);
 482
 483         ret_push = ust_app_push_metadata(ust_reg, socket, 1);
 484         if (ret_push < 0) {
 485                 ERR("Pushing metadata");
 486                 ret = -1;
 487                 goto end;
 488         }
 489         DBG("UST Consumer metadata pushed successfully");
 490         ret = 0;
 491
 492 end:
 493         pthread_mutex_unlock(socket->lock);
 494         rcu_read_unlock();
 495         return ret;
 496 }