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