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