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
 113         assert(ua_sess);
 114         assert(ua_chan);
 115         assert(socket);
 116         assert(consumer);
 117         assert(registry);
 118
 119         DBG2("Asking UST consumer for channel");
 120
 121         /* Get and create full trace path of session. */
 122         if (ua_sess->output_traces) {
 123                 pathname = setup_trace_path(consumer, ua_sess);
 124                 if (!pathname) {
 125                         ret = -1;
 126                         goto error;
 127                 }
 128         }
 129
 130         /* Depending on the buffer type, a different channel key is used. */
 131         if (ua_sess->buffer_type == LTTNG_BUFFER_PER_UID) {
 132                 chan_reg_key = ua_chan->tracing_channel_id;
 133         } else {
 134                 chan_reg_key = ua_chan->key;
 135         }
 136
 137         if (ua_chan->attr.type == LTTNG_UST_CHAN_METADATA) {
 138                 chan_id = -1U;
 139         } else {
 140                 chan_reg = ust_registry_channel_find(registry, chan_reg_key);
 141                 assert(chan_reg);
 142                 chan_id = chan_reg->chan_id;
 143         }
 144
 145         switch (ua_chan->attr.output) {
 146         case LTTNG_UST_MMAP:
 147         default:
 148                 output = LTTNG_EVENT_MMAP;
 149                 break;
 150         }
 151
 152         consumer_init_ask_channel_comm_msg(&msg,
 153                         ua_chan->attr.subbuf_size,
 154                         ua_chan->attr.num_subbuf,
 155                         ua_chan->attr.overwrite,
 156                         ua_chan->attr.switch_timer_interval,
 157                         ua_chan->attr.read_timer_interval,
 158                         ua_sess->live_timer_interval,
 159                         output,
 160                         (int) ua_chan->attr.type,
 161                         ua_sess->tracing_id,
 162                         pathname,
 163                         ua_chan->name,
 164                         ua_sess->euid,
 165                         ua_sess->egid,
 166                         consumer->net_seq_index,
 167                         ua_chan->key,
 168                         registry->uuid,
 169                         chan_id,
 170                         ua_chan->tracefile_size,
 171                         ua_chan->tracefile_count,
 172                         ua_sess->id,
 173                         ua_sess->output_traces,
 174                         ua_sess->uid);
 175
 176         health_code_update();
 177
 178         ret = consumer_socket_send(socket, &msg, sizeof(msg));
 179         if (ret < 0) {
 180                 goto error;
 181         }
 182
 183         ret = consumer_recv_status_channel(socket, &key,
 184                         &ua_chan->expected_stream_count);
 185         if (ret < 0) {
 186                 goto error;
 187         }
 188         /* Communication protocol error. */
 189         assert(key == ua_chan->key);
 190         /* We need at least one where 1 stream for 1 cpu. */
 191         if (ua_sess->output_traces) {
 192                 assert(ua_chan->expected_stream_count > 0);
 193         }
 194
 195         DBG2("UST ask channel %" PRIu64 " successfully done with %u stream(s)", key,
 196                         ua_chan->expected_stream_count);
 197
 198 error:
 199         free(pathname);
 200         health_code_update();
 201         return ret;
 202 }
 203
 204 /*
 205  * Ask consumer to create a channel for a given session.
 206  *
 207  * Returns 0 on success else a negative value.
 208  */
 209 int ust_consumer_ask_channel(struct ust_app_session *ua_sess,
 210                 struct ust_app_channel *ua_chan, struct consumer_output *consumer,
 211                 struct consumer_socket *socket, struct ust_registry_session *registry)
 212 {
 213         int ret;
 214
 215         assert(ua_sess);
 216         assert(ua_chan);
 217         assert(consumer);
 218         assert(socket);
 219         assert(registry);
 220
 221         if (!consumer->enabled) {
 222                 ret = -LTTNG_ERR_NO_CONSUMER;
 223                 DBG3("Consumer is disabled");
 224                 goto error;
 225         }
 226
 227         pthread_mutex_lock(socket->lock);
 228
 229         ret = ask_channel_creation(ua_sess, ua_chan, consumer, socket, registry);
 230         if (ret < 0) {
 231                 goto error;
 232         }
 233
 234 error:
 235         pthread_mutex_unlock(socket->lock);
 236         return ret;
 237 }
 238
 239 /*
 240  * Send a get channel command to consumer using the given channel key.  The
 241  * channel object is populated and the stream list.
 242  *
 243  * Return 0 on success else a negative value.
 244  */
 245 int ust_consumer_get_channel(struct consumer_socket *socket,
 246                 struct ust_app_channel *ua_chan)
 247 {
 248         int ret;
 249         struct lttcomm_consumer_msg msg;
 250
 251         assert(ua_chan);
 252         assert(socket);
 253
 254         memset(&msg, 0, sizeof(msg));
 255         msg.cmd_type = LTTNG_CONSUMER_GET_CHANNEL;
 256         msg.u.get_channel.key = ua_chan->key;
 257
 258         pthread_mutex_lock(socket->lock);
 259         health_code_update();
 260
 261         /* Send command and wait for OK reply. */
 262         ret = consumer_send_msg(socket, &msg);
 263         if (ret < 0) {
 264                 goto error;
 265         }
 266
 267         /* First, get the channel from consumer. */
 268         ret = ustctl_recv_channel_from_consumer(*socket->fd_ptr, &ua_chan->obj);
 269         if (ret < 0) {
 270                 if (ret != -EPIPE) {
 271                         ERR("Error recv channel from consumer %d with ret %d",
 272                                         *socket->fd_ptr, ret);
 273                 } else {
 274                         DBG3("UST app recv channel from consumer. Consumer is dead.");
 275                 }
 276                 goto error;
 277         }
 278
 279         /* Next, get all streams. */
 280         while (1) {
 281                 struct ust_app_stream *stream;
 282
 283                 /* Create UST stream */
 284                 stream = ust_app_alloc_stream();
 285                 if (stream == NULL) {
 286                         ret = -ENOMEM;
 287                         goto error;
 288                 }
 289
 290                 /* Stream object is populated by this call if successful. */
 291                 ret = ustctl_recv_stream_from_consumer(*socket->fd_ptr, &stream->obj);
 292                 if (ret < 0) {
 293                         free(stream);
 294                         if (ret == -LTTNG_UST_ERR_NOENT) {
 295                                 DBG3("UST app consumer has no more stream available");
 296                                 ret = 0;
 297                                 break;
 298                         }
 299                         if (ret != -EPIPE) {
 300                                 ERR("Recv stream from consumer %d with ret %d",
 301                                                 *socket->fd_ptr, ret);
 302                         } else {
 303                                 DBG3("UST app recv stream from consumer. Consumer is dead.");
 304                         }
 305                         goto error;
 306                 }
 307
 308                 /* Order is important this is why a list is used. */
 309                 cds_list_add_tail(&stream->list, &ua_chan->streams.head);
 310                 ua_chan->streams.count++;
 311
 312                 DBG2("UST app stream %d received successfully", ua_chan->streams.count);
 313         }
 314
 315         /* This MUST match or else we have a synchronization problem. */
 316         assert(ua_chan->expected_stream_count == ua_chan->streams.count);
 317
 318         /* Wait for confirmation that we can proceed with the streams. */
 319         ret = consumer_recv_status_reply(socket);
 320         if (ret < 0) {
 321                 goto error;
 322         }
 323
 324 error:
 325         health_code_update();
 326         pthread_mutex_unlock(socket->lock);
 327         return ret;
 328 }
 329
 330 /*
 331  * Send a destroy channel command to consumer using the given channel key.
 332  *
 333  * Note that this command MUST be used prior to a successful
 334  * LTTNG_CONSUMER_GET_CHANNEL because once this command is done successfully,
 335  * the streams are dispatched to the consumer threads and MUST be teardown
 336  * through the hang up process.
 337  *
 338  * Return 0 on success else a negative value.
 339  */
 340 int ust_consumer_destroy_channel(struct consumer_socket *socket,
 341                 struct ust_app_channel *ua_chan)
 342 {
 343         int ret;
 344         struct lttcomm_consumer_msg msg;
 345
 346         assert(ua_chan);
 347         assert(socket);
 348
 349         memset(&msg, 0, sizeof(msg));
 350         msg.cmd_type = LTTNG_CONSUMER_DESTROY_CHANNEL;
 351         msg.u.destroy_channel.key = ua_chan->key;
 352
 353         pthread_mutex_lock(socket->lock);
 354         health_code_update();
 355
 356         ret = consumer_send_msg(socket, &msg);
 357         if (ret < 0) {
 358                 goto error;
 359         }
 360
 361 error:
 362         health_code_update();
 363         pthread_mutex_unlock(socket->lock);
 364         return ret;
 365 }
 366
 367 /*
 368  * Send a given stream to UST tracer.
 369  *
 370  * On success return 0 else a negative value.
 371  */
 372 int ust_consumer_send_stream_to_ust(struct ust_app *app,
 373                 struct ust_app_channel *channel, struct ust_app_stream *stream)
 374 {
 375         int ret;
 376
 377         assert(app);
 378         assert(stream);
 379         assert(channel);
 380
 381         DBG2("UST consumer send stream to app %d", app->sock);
 382
 383         /* Relay stream to application. */
 384         ret = ustctl_send_stream_to_ust(app->sock, channel->obj, stream->obj);
 385         if (ret < 0) {
 386                 if (ret != -EPIPE && ret != -LTTNG_UST_ERR_EXITING) {
 387                         ERR("ustctl send stream handle %d to app pid: %d with ret %d",
 388                                         stream->obj->handle, app->pid, ret);
 389                 } else {
 390                         DBG3("UST app send stream to ust failed. Application is dead.");
 391                 }
 392                 goto error;
 393         }
 394         channel->handle = channel->obj->handle;
 395
 396 error:
 397         return ret;
 398 }
 399
 400 /*
 401  * Send channel previously received from the consumer to the UST tracer.
 402  *
 403  * On success return 0 else a negative value.
 404  */
 405 int ust_consumer_send_channel_to_ust(struct ust_app *app,
 406                 struct ust_app_session *ua_sess, struct ust_app_channel *channel)
 407 {
 408         int ret;
 409
 410         assert(app);
 411         assert(ua_sess);
 412         assert(channel);
 413         assert(channel->obj);
 414
 415         DBG2("UST app send channel to sock %d pid %d (name: %s, key: %" PRIu64 ")",
 416                         app->sock, app->pid, channel->name, channel->tracing_channel_id);
 417
 418         /* Send stream to application. */
 419         ret = ustctl_send_channel_to_ust(app->sock, ua_sess->handle, channel->obj);
 420         if (ret < 0) {
 421                 if (ret != -EPIPE && ret != -LTTNG_UST_ERR_EXITING) {
 422                         ERR("Error ustctl send channel %s to app pid: %d with ret %d",
 423                                         channel->name, app->pid, ret);
 424                 } else {
 425                         DBG3("UST app send channel to ust failed. Application is dead.");
 426                 }
 427                 goto error;
 428         }
 429
 430 error:
 431         return ret;
 432 }
 433
 434 /*
 435  * Handle the metadata requests from the UST consumer
 436  *
 437  * Return 0 on success else a negative value.
 438  */
 439 int ust_consumer_metadata_request(struct consumer_socket *socket)
 440 {
 441         int ret;
 442         ssize_t ret_push;
 443         struct lttcomm_metadata_request_msg request;
 444         struct buffer_reg_uid *reg_uid;
 445         struct ust_registry_session *ust_reg;
 446         struct lttcomm_consumer_msg msg;
 447
 448         assert(socket);
 449
 450         rcu_read_lock();
 451         health_code_update();
 452
 453         /* Wait for a metadata request */
 454         pthread_mutex_lock(socket->lock);
 455         ret = consumer_socket_recv(socket, &request, sizeof(request));
 456         pthread_mutex_unlock(socket->lock);
 457         if (ret < 0) {
 458                 goto end;
 459         }
 460
 461         DBG("Metadata request received for session %" PRIu64 ", key %" PRIu64,
 462                         request.session_id, request.key);
 463
 464         reg_uid = buffer_reg_uid_find(request.session_id,
 465                         request.bits_per_long, request.uid);
 466         if (reg_uid) {
 467                 ust_reg = reg_uid->registry->reg.ust;
 468         } else {
 469                 struct buffer_reg_pid *reg_pid =
 470                         buffer_reg_pid_find(request.session_id_per_pid);
 471                 if (!reg_pid) {
 472                         DBG("PID registry not found for session id %" PRIu64,
 473                                         request.session_id_per_pid);
 474
 475                         memset(&msg, 0, sizeof(msg));
 476                         msg.cmd_type = LTTNG_ERR_UND;
 477                         (void) consumer_send_msg(socket, &msg);
 478                         /*
 479                          * This is possible since the session might have been destroyed
 480                          * during a consumer metadata request. So here, return gracefully
 481                          * because the destroy session will push the remaining metadata to
 482                          * the consumer.
 483                          */
 484                         ret = 0;
 485                         goto end;
 486                 }
 487                 ust_reg = reg_pid->registry->reg.ust;
 488         }
 489         assert(ust_reg);
 490
 491         pthread_mutex_lock(&ust_reg->lock);
 492         ret_push = ust_app_push_metadata(ust_reg, socket, 1);
 493         pthread_mutex_unlock(&ust_reg->lock);
 494         if (ret_push < 0) {
 495                 ERR("Pushing metadata");
 496                 ret = -1;
 497                 goto end;
 498         }
 499         DBG("UST Consumer metadata pushed successfully");
 500         ret = 0;
 501
 502 end:
 503         rcu_read_unlock();
 504         return ret;
 505 }