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
 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         }
 160
 161         switch (ua_chan->attr.output) {
 162         case LTTNG_UST_MMAP:
 163         default:
 164                 output = LTTNG_EVENT_MMAP;
 165                 break;
 166         }
 167
 168         consumer_init_ask_channel_comm_msg(&msg,
 169                         ua_chan->attr.subbuf_size,
 170                         ua_chan->attr.num_subbuf,
 171                         ua_chan->attr.overwrite,
 172                         ua_chan->attr.switch_timer_interval,
 173                         ua_chan->attr.read_timer_interval,
 174                         ua_sess->live_timer_interval,
 175                         output,
 176                         (int) ua_chan->attr.type,
 177                         ua_sess->tracing_id,
 178                         pathname,
 179                         ua_chan->name,
 180                         ua_sess->euid,
 181                         ua_sess->egid,
 182                         consumer->net_seq_index,
 183                         ua_chan->key,
 184                         registry->uuid,
 185                         chan_id,
 186                         ua_chan->tracefile_size,
 187                         ua_chan->tracefile_count,
 188                         ua_sess->id,
 189                         ua_sess->output_traces,
 190                         ua_sess->uid,
 191                         shm_path);
 192
 193         health_code_update();
 194
 195         ret = consumer_socket_send(socket, &msg, sizeof(msg));
 196         if (ret < 0) {
 197                 goto error;
 198         }
 199
 200         ret = consumer_recv_status_channel(socket, &key,
 201                         &ua_chan->expected_stream_count);
 202         if (ret < 0) {
 203                 goto error;
 204         }
 205         /* Communication protocol error. */
 206         assert(key == ua_chan->key);
 207         /* We need at least one where 1 stream for 1 cpu. */
 208         if (ua_sess->output_traces) {
 209                 assert(ua_chan->expected_stream_count > 0);
 210         }
 211
 212         DBG2("UST ask channel %" PRIu64 " successfully done with %u stream(s)", key,
 213                         ua_chan->expected_stream_count);
 214
 215 error:
 216         free(pathname);
 217         health_code_update();
 218         return ret;
 219 }
 220
 221 /*
 222  * Ask consumer to create a channel for a given session.
 223  *
 224  * Returns 0 on success else a negative value.
 225  */
 226 int ust_consumer_ask_channel(struct ust_app_session *ua_sess,
 227                 struct ust_app_channel *ua_chan, struct consumer_output *consumer,
 228                 struct consumer_socket *socket, struct ust_registry_session *registry)
 229 {
 230         int ret;
 231
 232         assert(ua_sess);
 233         assert(ua_chan);
 234         assert(consumer);
 235         assert(socket);
 236         assert(registry);
 237
 238         if (!consumer->enabled) {
 239                 ret = -LTTNG_ERR_NO_CONSUMER;
 240                 DBG3("Consumer is disabled");
 241                 goto error;
 242         }
 243
 244         pthread_mutex_lock(socket->lock);
 245
 246         ret = ask_channel_creation(ua_sess, ua_chan, consumer, socket, registry);
 247         if (ret < 0) {
 248                 goto error;
 249         }
 250
 251 error:
 252         pthread_mutex_unlock(socket->lock);
 253         return ret;
 254 }
 255
 256 /*
 257  * Send a get channel command to consumer using the given channel key.  The
 258  * channel object is populated and the stream list.
 259  *
 260  * Return 0 on success else a negative value.
 261  */
 262 int ust_consumer_get_channel(struct consumer_socket *socket,
 263                 struct ust_app_channel *ua_chan)
 264 {
 265         int ret;
 266         struct lttcomm_consumer_msg msg;
 267
 268         assert(ua_chan);
 269         assert(socket);
 270
 271         memset(&msg, 0, sizeof(msg));
 272         msg.cmd_type = LTTNG_CONSUMER_GET_CHANNEL;
 273         msg.u.get_channel.key = ua_chan->key;
 274
 275         pthread_mutex_lock(socket->lock);
 276         health_code_update();
 277
 278         /* Send command and wait for OK reply. */
 279         ret = consumer_send_msg(socket, &msg);
 280         if (ret < 0) {
 281                 goto error;
 282         }
 283
 284         /* First, get the channel from consumer. */
 285         ret = ustctl_recv_channel_from_consumer(*socket->fd_ptr, &ua_chan->obj);
 286         if (ret < 0) {
 287                 if (ret != -EPIPE) {
 288                         ERR("Error recv channel from consumer %d with ret %d",
 289                                         *socket->fd_ptr, ret);
 290                 } else {
 291                         DBG3("UST app recv channel from consumer. Consumer is dead.");
 292                 }
 293                 goto error;
 294         }
 295
 296         /* Next, get all streams. */
 297         while (1) {
 298                 struct ust_app_stream *stream;
 299
 300                 /* Create UST stream */
 301                 stream = ust_app_alloc_stream();
 302                 if (stream == NULL) {
 303                         ret = -ENOMEM;
 304                         goto error;
 305                 }
 306
 307                 /* Stream object is populated by this call if successful. */
 308                 ret = ustctl_recv_stream_from_consumer(*socket->fd_ptr, &stream->obj);
 309                 if (ret < 0) {
 310                         free(stream);
 311                         if (ret == -LTTNG_UST_ERR_NOENT) {
 312                                 DBG3("UST app consumer has no more stream available");
 313                                 ret = 0;
 314                                 break;
 315                         }
 316                         if (ret != -EPIPE) {
 317                                 ERR("Recv stream from consumer %d with ret %d",
 318                                                 *socket->fd_ptr, ret);
 319                         } else {
 320                                 DBG3("UST app recv stream from consumer. Consumer is dead.");
 321                         }
 322                         goto error;
 323                 }
 324
 325                 /* Order is important this is why a list is used. */
 326                 cds_list_add_tail(&stream->list, &ua_chan->streams.head);
 327                 ua_chan->streams.count++;
 328
 329                 DBG2("UST app stream %d received successfully", ua_chan->streams.count);
 330         }
 331
 332         /* This MUST match or else we have a synchronization problem. */
 333         assert(ua_chan->expected_stream_count == ua_chan->streams.count);
 334
 335         /* Wait for confirmation that we can proceed with the streams. */
 336         ret = consumer_recv_status_reply(socket);
 337         if (ret < 0) {
 338                 goto error;
 339         }
 340
 341 error:
 342         health_code_update();
 343         pthread_mutex_unlock(socket->lock);
 344         return ret;
 345 }
 346
 347 /*
 348  * Send a destroy channel command to consumer using the given channel key.
 349  *
 350  * Note that this command MUST be used prior to a successful
 351  * LTTNG_CONSUMER_GET_CHANNEL because once this command is done successfully,
 352  * the streams are dispatched to the consumer threads and MUST be teardown
 353  * through the hang up process.
 354  *
 355  * Return 0 on success else a negative value.
 356  */
 357 int ust_consumer_destroy_channel(struct consumer_socket *socket,
 358                 struct ust_app_channel *ua_chan)
 359 {
 360         int ret;
 361         struct lttcomm_consumer_msg msg;
 362
 363         assert(ua_chan);
 364         assert(socket);
 365
 366         memset(&msg, 0, sizeof(msg));
 367         msg.cmd_type = LTTNG_CONSUMER_DESTROY_CHANNEL;
 368         msg.u.destroy_channel.key = ua_chan->key;
 369
 370         pthread_mutex_lock(socket->lock);
 371         health_code_update();
 372
 373         ret = consumer_send_msg(socket, &msg);
 374         if (ret < 0) {
 375                 goto error;
 376         }
 377
 378 error:
 379         health_code_update();
 380         pthread_mutex_unlock(socket->lock);
 381         return ret;
 382 }
 383
 384 /*
 385  * Send a given stream to UST tracer.
 386  *
 387  * On success return 0 else a negative value.
 388  */
 389 int ust_consumer_send_stream_to_ust(struct ust_app *app,
 390                 struct ust_app_channel *channel, struct ust_app_stream *stream)
 391 {
 392         int ret;
 393
 394         assert(app);
 395         assert(stream);
 396         assert(channel);
 397
 398         DBG2("UST consumer send stream to app %d", app->sock);
 399
 400         /* Relay stream to application. */
 401         ret = ustctl_send_stream_to_ust(app->sock, channel->obj, stream->obj);
 402         if (ret < 0) {
 403                 if (ret != -EPIPE && ret != -LTTNG_UST_ERR_EXITING) {
 404                         ERR("ustctl send stream handle %d to app pid: %d with ret %d",
 405                                         stream->obj->handle, app->pid, ret);
 406                 } else {
 407                         DBG3("UST app send stream to ust failed. Application is dead.");
 408                 }
 409                 goto error;
 410         }
 411         channel->handle = channel->obj->handle;
 412
 413 error:
 414         return ret;
 415 }
 416
 417 /*
 418  * Send channel previously received from the consumer to the UST tracer.
 419  *
 420  * On success return 0 else a negative value.
 421  */
 422 int ust_consumer_send_channel_to_ust(struct ust_app *app,
 423                 struct ust_app_session *ua_sess, struct ust_app_channel *channel)
 424 {
 425         int ret;
 426
 427         assert(app);
 428         assert(ua_sess);
 429         assert(channel);
 430         assert(channel->obj);
 431
 432         DBG2("UST app send channel to sock %d pid %d (name: %s, key: %" PRIu64 ")",
 433                         app->sock, app->pid, channel->name, channel->tracing_channel_id);
 434
 435         /* Send stream to application. */
 436         ret = ustctl_send_channel_to_ust(app->sock, ua_sess->handle, channel->obj);
 437         if (ret < 0) {
 438                 if (ret != -EPIPE && ret != -LTTNG_UST_ERR_EXITING) {
 439                         ERR("Error ustctl send channel %s to app pid: %d with ret %d",
 440                                         channel->name, app->pid, ret);
 441                 } else {
 442                         DBG3("UST app send channel to ust failed. Application is dead.");
 443                 }
 444                 goto error;
 445         }
 446
 447 error:
 448         return ret;
 449 }
 450
 451 /*
 452  * Handle the metadata requests from the UST consumer
 453  *
 454  * Return 0 on success else a negative value.
 455  */
 456 int ust_consumer_metadata_request(struct consumer_socket *socket)
 457 {
 458         int ret;
 459         ssize_t ret_push;
 460         struct lttcomm_metadata_request_msg request;
 461         struct buffer_reg_uid *reg_uid;
 462         struct ust_registry_session *ust_reg;
 463         struct lttcomm_consumer_msg msg;
 464
 465         assert(socket);
 466
 467         rcu_read_lock();
 468         health_code_update();
 469
 470         /* Wait for a metadata request */
 471         pthread_mutex_lock(socket->lock);
 472         ret = consumer_socket_recv(socket, &request, sizeof(request));
 473         pthread_mutex_unlock(socket->lock);
 474         if (ret < 0) {
 475                 goto end;
 476         }
 477
 478         DBG("Metadata request received for session %" PRIu64 ", key %" PRIu64,
 479                         request.session_id, request.key);
 480
 481         reg_uid = buffer_reg_uid_find(request.session_id,
 482                         request.bits_per_long, request.uid);
 483         if (reg_uid) {
 484                 ust_reg = reg_uid->registry->reg.ust;
 485         } else {
 486                 struct buffer_reg_pid *reg_pid =
 487                         buffer_reg_pid_find(request.session_id_per_pid);
 488                 if (!reg_pid) {
 489                         DBG("PID registry not found for session id %" PRIu64,
 490                                         request.session_id_per_pid);
 491
 492                         memset(&msg, 0, sizeof(msg));
 493                         msg.cmd_type = LTTNG_ERR_UND;
 494                         (void) consumer_send_msg(socket, &msg);
 495                         /*
 496                          * This is possible since the session might have been destroyed
 497                          * during a consumer metadata request. So here, return gracefully
 498                          * because the destroy session will push the remaining metadata to
 499                          * the consumer.
 500                          */
 501                         ret = 0;
 502                         goto end;
 503                 }
 504                 ust_reg = reg_pid->registry->reg.ust;
 505         }
 506         assert(ust_reg);
 507
 508         pthread_mutex_lock(&ust_reg->lock);
 509         ret_push = ust_app_push_metadata(ust_reg, socket, 1);
 510         pthread_mutex_unlock(&ust_reg->lock);
 511         if (ret_push < 0) {
 512                 ERR("Pushing metadata");
 513                 ret = -1;
 514                 goto end;
 515         }
 516         DBG("UST Consumer metadata pushed successfully");
 517         ret = 0;
 518
 519 end:
 520         rcu_read_unlock();
 521         return ret;
 522 }