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