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