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-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 (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, 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
 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         switch (ua_chan->attr.output) {
 145         case LTTNG_UST_MMAP:
 146         default:
 147                 output = LTTNG_EVENT_MMAP;
 148                 break;
 149         }
 150
 151         consumer_init_ask_channel_comm_msg(&msg,
 152                         ua_chan->attr.subbuf_size,
 153                         ua_chan->attr.num_subbuf,
 154                         ua_chan->attr.overwrite,
 155                         ua_chan->attr.switch_timer_interval,
 156                         ua_chan->attr.read_timer_interval,
 157                         ua_sess->live_timer_interval,
 158                         output,
 159                         (int) ua_chan->attr.type,
 160                         ua_sess->tracing_id,
 161                         pathname,
 162                         ua_chan->name,
 163                         ua_sess->euid,
 164                         ua_sess->egid,
 165                         consumer->net_seq_index,
 166                         ua_chan->key,
 167                         registry->uuid,
 168                         chan_id,
 169                         ua_chan->tracefile_size,
 170                         ua_chan->tracefile_count,
 171                         ua_sess->id,
 172                         ua_sess->output_traces,
 173                         ua_sess->uid);
 174
 175         health_code_update();
 176
 177         ret = consumer_socket_send(socket, &msg, sizeof(msg));
 178         if (ret < 0) {
 179                 goto error;
 180         }
 181
 182         ret = consumer_recv_status_channel(socket, &key,
 183                         &ua_chan->expected_stream_count);
 184         if (ret < 0) {
 185                 goto error;
 186         }
 187         /* Communication protocol error. */
 188         assert(key == ua_chan->key);
 189         /* We need at least one where 1 stream for 1 cpu. */
 190         if (ua_sess->output_traces) {
 191                 assert(ua_chan->expected_stream_count > 0);
 192         }
 193
 194         DBG2("UST ask channel %" PRIu64 " successfully done with %u stream(s)", key,
 195                         ua_chan->expected_stream_count);
 196
 197 error:
 198         free(pathname);
 199         health_code_update();
 200         return ret;
 201 }
 202
 203 /*
 204  * Ask consumer to create a channel for a given session.
 205  *
 206  * Returns 0 on success else a negative value.
 207  */
 208 int ust_consumer_ask_channel(struct ust_app_session *ua_sess,
 209                 struct ust_app_channel *ua_chan, struct consumer_output *consumer,
 210                 struct consumer_socket *socket, struct ust_registry_session *registry)
 211 {
 212         int ret;
 213
 214         assert(ua_sess);
 215         assert(ua_chan);
 216         assert(consumer);
 217         assert(socket);
 218         assert(registry);
 219
 220         if (!consumer->enabled) {
 221                 ret = -LTTNG_ERR_NO_CONSUMER;
 222                 DBG3("Consumer is disabled");
 223                 goto error;
 224         }
 225
 226         pthread_mutex_lock(socket->lock);
 227
 228         ret = ask_channel_creation(ua_sess, ua_chan, consumer, socket, registry);
 229         if (ret < 0) {
 230                 goto error;
 231         }
 232
 233 error:
 234         pthread_mutex_unlock(socket->lock);
 235         return ret;
 236 }
 237
 238 /*
 239  * Send a get channel command to consumer using the given channel key.  The
 240  * channel object is populated and the stream list.
 241  *
 242  * Return 0 on success else a negative value.
 243  */
 244 int ust_consumer_get_channel(struct consumer_socket *socket,
 245                 struct ust_app_channel *ua_chan)
 246 {
 247         int ret;
 248         struct lttcomm_consumer_msg msg;
 249
 250         assert(ua_chan);
 251         assert(socket);
 252
 253         memset(&msg, 0, sizeof(msg));
 254         msg.cmd_type = LTTNG_CONSUMER_GET_CHANNEL;
 255         msg.u.get_channel.key = ua_chan->key;
 256
 257         pthread_mutex_lock(socket->lock);
 258         health_code_update();
 259
 260         /* Send command and wait for OK reply. */
 261         ret = consumer_send_msg(socket, &msg);
 262         if (ret < 0) {
 263                 goto error;
 264         }
 265
 266         /* First, get the channel from consumer. */
 267         ret = ustctl_recv_channel_from_consumer(*socket->fd_ptr, &ua_chan->obj);
 268         if (ret < 0) {
 269                 if (ret != -EPIPE) {
 270                         ERR("Error recv channel from consumer %d with ret %d",
 271                                         *socket->fd_ptr, ret);
 272                 } else {
 273                         DBG3("UST app recv channel from consumer. Consumer is dead.");
 274                 }
 275                 goto error;
 276         }
 277
 278         /* Next, get all streams. */
 279         while (1) {
 280                 struct ust_app_stream *stream;
 281
 282                 /* Create UST stream */
 283                 stream = ust_app_alloc_stream();
 284                 if (stream == NULL) {
 285                         ret = -ENOMEM;
 286                         goto error;
 287                 }
 288
 289                 /* Stream object is populated by this call if successful. */
 290                 ret = ustctl_recv_stream_from_consumer(*socket->fd_ptr, &stream->obj);
 291                 if (ret < 0) {
 292                         free(stream);
 293                         if (ret == -LTTNG_UST_ERR_NOENT) {
 294                                 DBG3("UST app consumer has no more stream available");
 295                                 ret = 0;
 296                                 break;
 297                         }
 298                         if (ret != -EPIPE) {
 299                                 ERR("Recv stream from consumer %d with ret %d",
 300                                                 *socket->fd_ptr, ret);
 301                         } else {
 302                                 DBG3("UST app recv stream from consumer. Consumer is dead.");
 303                         }
 304                         goto error;
 305                 }
 306
 307                 /* Order is important this is why a list is used. */
 308                 cds_list_add_tail(&stream->list, &ua_chan->streams.head);
 309                 ua_chan->streams.count++;
 310
 311                 DBG2("UST app stream %d received successfully", ua_chan->streams.count);
 312         }
 313
 314         /* This MUST match or else we have a synchronization problem. */
 315         assert(ua_chan->expected_stream_count == ua_chan->streams.count);
 316
 317         /* Wait for confirmation that we can proceed with the streams. */
 318         ret = consumer_recv_status_reply(socket);
 319         if (ret < 0) {
 320                 goto error;
 321         }
 322
 323 error:
 324         health_code_update();
 325         pthread_mutex_unlock(socket->lock);
 326         return ret;
 327 }
 328
 329 /*
 330  * Send a destroy channel command to consumer using the given channel key.
 331  *
 332  * Note that this command MUST be used prior to a successful
 333  * LTTNG_CONSUMER_GET_CHANNEL because once this command is done successfully,
 334  * the streams are dispatched to the consumer threads and MUST be teardown
 335  * through the hang up process.
 336  *
 337  * Return 0 on success else a negative value.
 338  */
 339 int ust_consumer_destroy_channel(struct consumer_socket *socket,
 340                 struct ust_app_channel *ua_chan)
 341 {
 342         int ret;
 343         struct lttcomm_consumer_msg msg;
 344
 345         assert(ua_chan);
 346         assert(socket);
 347
 348         memset(&msg, 0, sizeof(msg));
 349         msg.cmd_type = LTTNG_CONSUMER_DESTROY_CHANNEL;
 350         msg.u.destroy_channel.key = ua_chan->key;
 351
 352         pthread_mutex_lock(socket->lock);
 353         health_code_update();
 354
 355         ret = consumer_send_msg(socket, &msg);
 356         if (ret < 0) {
 357                 goto error;
 358         }
 359
 360 error:
 361         health_code_update();
 362         pthread_mutex_unlock(socket->lock);
 363         return ret;
 364 }
 365
 366 /*
 367  * Send a given stream to UST tracer.
 368  *
 369  * On success return 0 else a negative value.
 370  */
 371 int ust_consumer_send_stream_to_ust(struct ust_app *app,
 372                 struct ust_app_channel *channel, struct ust_app_stream *stream)
 373 {
 374         int ret;
 375
 376         assert(app);
 377         assert(stream);
 378         assert(channel);
 379
 380         DBG2("UST consumer send stream to app %d", app->sock);
 381
 382         /* Relay stream to application. */
 383         ret = ustctl_send_stream_to_ust(app->sock, channel->obj, stream->obj);
 384         if (ret < 0) {
 385                 if (ret != -EPIPE && ret != -LTTNG_UST_ERR_EXITING) {
 386                         ERR("ustctl send stream handle %d to app pid: %d with ret %d",
 387                                         stream->obj->handle, app->pid, ret);
 388                 } else {
 389                         DBG3("UST app send stream to ust failed. Application is dead.");
 390                 }
 391                 goto error;
 392         }
 393         channel->handle = channel->obj->handle;
 394
 395 error:
 396         return ret;
 397 }
 398
 399 /*
 400  * Send channel previously received from the consumer to the UST tracer.
 401  *
 402  * On success return 0 else a negative value.
 403  */
 404 int ust_consumer_send_channel_to_ust(struct ust_app *app,
 405                 struct ust_app_session *ua_sess, struct ust_app_channel *channel)
 406 {
 407         int ret;
 408
 409         assert(app);
 410         assert(ua_sess);
 411         assert(channel);
 412         assert(channel->obj);
 413
 414         DBG2("UST app send channel to sock %d pid %d (name: %s, key: %" PRIu64 ")",
 415                         app->sock, app->pid, channel->name, channel->tracing_channel_id);
 416
 417         /* Send stream to application. */
 418         ret = ustctl_send_channel_to_ust(app->sock, ua_sess->handle, channel->obj);
 419         if (ret < 0) {
 420                 if (ret != -EPIPE && ret != -LTTNG_UST_ERR_EXITING) {
 421                         ERR("Error ustctl send channel %s to app pid: %d with ret %d",
 422                                         channel->name, app->pid, ret);
 423                 } else {
 424                         DBG3("UST app send channel to ust failed. Application is dead.");
 425                 }
 426                 goto error;
 427         }
 428
 429 error:
 430         return ret;
 431 }
 432
 433 /*
 434  * Handle the metadata requests from the UST consumer
 435  *
 436  * Return 0 on success else a negative value.
 437  */
 438 int ust_consumer_metadata_request(struct consumer_socket *socket)
 439 {
 440         int ret;
 441         ssize_t ret_push;
 442         struct lttcomm_metadata_request_msg request;
 443         struct buffer_reg_uid *reg_uid;
 444         struct ust_registry_session *ust_reg;
 445         struct lttcomm_consumer_msg msg;
 446
 447         assert(socket);
 448
 449         rcu_read_lock();
 450         pthread_mutex_lock(socket->lock);
 451
 452         health_code_update();
 453
 454         /* Wait for a metadata request */
 455         ret = consumer_socket_recv(socket, &request, sizeof(request));
 456         if (ret < 0) {
 457                 goto end;
 458         }
 459
 460         DBG("Metadata request received for session %" PRIu64 ", key %" PRIu64,
 461                         request.session_id, request.key);
 462
 463         reg_uid = buffer_reg_uid_find(request.session_id,
 464                         request.bits_per_long, request.uid);
 465         if (reg_uid) {
 466                 ust_reg = reg_uid->registry->reg.ust;
 467         } else {
 468                 struct buffer_reg_pid *reg_pid =
 469                         buffer_reg_pid_find(request.session_id_per_pid);
 470                 if (!reg_pid) {
 471                         DBG("PID registry not found for session id %" PRIu64,
 472                                         request.session_id_per_pid);
 473
 474                         memset(&msg, 0, sizeof(msg));
 475                         msg.cmd_type = LTTNG_ERR_UND;
 476                         (void) consumer_send_msg(socket, &msg);
 477                         /*
 478                          * This is possible since the session might have been destroyed
 479                          * during a consumer metadata request. So here, return gracefully
 480                          * because the destroy session will push the remaining metadata to
 481                          * the consumer.
 482                          */
 483                         ret = 0;
 484                         goto end;
 485                 }
 486                 ust_reg = reg_pid->registry->reg.ust;
 487         }
 488         assert(ust_reg);
 489
 490         ret_push = ust_app_push_metadata(ust_reg, socket, 1);
 491         if (ret_push < 0) {
 492                 ERR("Pushing metadata");
 493                 ret = -1;
 494                 goto end;
 495         }
 496         DBG("UST Consumer metadata pushed successfully");
 497         ret = 0;
 498
 499 end:
 500         pthread_mutex_unlock(socket->lock);
 501         rcu_read_unlock();
 502         return ret;
 503 }