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