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