src/bin/lttng-sessiond/channel.c

   1 /*
   2  * Copyright (C) 2011 - David Goulet <david.goulet@polymtl.ca>
   3  * Copyright (C) 2016 - Jérémie Galarneau <jeremie.galarneau@efficios.com>
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License, version 2 only,
   7  * as published by the Free Software Foundation.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License along
  15  * with this program; if not, write to the Free Software Foundation, Inc.,
  16  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  17  */
  18
  19 #define _LGPL_SOURCE
  20 #include <inttypes.h>
  21 #include <string.h>
  22 #include <unistd.h>
  23
  24 #include <common/common.h>
  25 #include <common/defaults.h>
  26 #include <common/sessiond-comm/sessiond-comm.h>
  27
  28 #include "channel.h"
  29 #include "lttng-sessiond.h"
  30 #include "kernel.h"
  31 #include "ust-ctl.h"
  32 #include "utils.h"
  33 #include "ust-app.h"
  34 #include "agent.h"
  35
  36 /*
  37  * Return allocated channel attributes.
  38  */
  39 struct lttng_channel *channel_new_default_attr(int dom,
  40                 enum lttng_buffer_type type)
  41 {
  42         struct lttng_channel *chan;
  43         const char *channel_name = DEFAULT_CHANNEL_NAME;
  44         struct lttng_channel_extended *extended_attr = NULL;
  45
  46         chan = zmalloc(sizeof(struct lttng_channel));
  47         if (chan == NULL) {
  48                 PERROR("zmalloc channel init");
  49                 goto error_alloc;
  50         }
  51
  52         extended_attr = zmalloc(sizeof(struct lttng_channel_extended));
  53         if (!extended_attr) {
  54                 PERROR("zmalloc channel extended init");
  55                 goto error;
  56         }
  57
  58         chan->attr.extended.ptr = extended_attr;
  59
  60         /* Same for all domains. */
  61         chan->attr.overwrite = DEFAULT_CHANNEL_OVERWRITE;
  62         chan->attr.tracefile_size = DEFAULT_CHANNEL_TRACEFILE_SIZE;
  63         chan->attr.tracefile_count = DEFAULT_CHANNEL_TRACEFILE_COUNT;
  64
  65         switch (dom) {
  66         case LTTNG_DOMAIN_KERNEL:
  67                 assert(type == LTTNG_BUFFER_GLOBAL);
  68                 chan->attr.subbuf_size =
  69                         default_get_kernel_channel_subbuf_size();
  70                 chan->attr.num_subbuf = DEFAULT_KERNEL_CHANNEL_SUBBUF_NUM;
  71                 chan->attr.output = DEFAULT_KERNEL_CHANNEL_OUTPUT;
  72                 chan->attr.switch_timer_interval = DEFAULT_KERNEL_CHANNEL_SWITCH_TIMER;
  73                 chan->attr.read_timer_interval = DEFAULT_KERNEL_CHANNEL_READ_TIMER;
  74                 chan->attr.live_timer_interval = DEFAULT_KERNEL_CHANNEL_LIVE_TIMER;
  75                 extended_attr->blocking_timeout = DEFAULT_KERNEL_CHANNEL_BLOCKING_TIMEOUT;
  76                 extended_attr->monitor_timer_interval =
  77                         DEFAULT_KERNEL_CHANNEL_MONITOR_TIMER;
  78                 break;
  79         case LTTNG_DOMAIN_JUL:
  80                 channel_name = DEFAULT_JUL_CHANNEL_NAME;
  81                 goto common_ust;
  82         case LTTNG_DOMAIN_LOG4J:
  83                 channel_name = DEFAULT_LOG4J_CHANNEL_NAME;
  84                 goto common_ust;
  85         case LTTNG_DOMAIN_PYTHON:
  86                 channel_name = DEFAULT_PYTHON_CHANNEL_NAME;
  87                 goto common_ust;
  88         case LTTNG_DOMAIN_UST:
  89 common_ust:
  90                 switch (type) {
  91                 case LTTNG_BUFFER_PER_UID:
  92                         chan->attr.subbuf_size = default_get_ust_uid_channel_subbuf_size();
  93                         chan->attr.num_subbuf = DEFAULT_UST_UID_CHANNEL_SUBBUF_NUM;
  94                         chan->attr.output = DEFAULT_UST_UID_CHANNEL_OUTPUT;
  95                         chan->attr.switch_timer_interval =
  96                                 DEFAULT_UST_UID_CHANNEL_SWITCH_TIMER;
  97                         chan->attr.read_timer_interval =
  98                                 DEFAULT_UST_UID_CHANNEL_READ_TIMER;
  99                         chan->attr.live_timer_interval =
 100                                 DEFAULT_UST_UID_CHANNEL_LIVE_TIMER;
 101                         extended_attr->blocking_timeout = DEFAULT_UST_UID_CHANNEL_BLOCKING_TIMEOUT;
 102                         extended_attr->monitor_timer_interval =
 103                                 DEFAULT_UST_UID_CHANNEL_MONITOR_TIMER;
 104                         break;
 105                 case LTTNG_BUFFER_PER_PID:
 106                 default:
 107                         chan->attr.subbuf_size = default_get_ust_pid_channel_subbuf_size();
 108                         chan->attr.num_subbuf = DEFAULT_UST_PID_CHANNEL_SUBBUF_NUM;
 109                         chan->attr.output = DEFAULT_UST_PID_CHANNEL_OUTPUT;
 110                         chan->attr.switch_timer_interval =
 111                                 DEFAULT_UST_PID_CHANNEL_SWITCH_TIMER;
 112                         chan->attr.read_timer_interval =
 113                                 DEFAULT_UST_PID_CHANNEL_READ_TIMER;
 114                         chan->attr.live_timer_interval =
 115                                 DEFAULT_UST_PID_CHANNEL_LIVE_TIMER;
 116                         extended_attr->blocking_timeout = DEFAULT_UST_PID_CHANNEL_BLOCKING_TIMEOUT;
 117                         extended_attr->monitor_timer_interval =
 118                                 DEFAULT_UST_PID_CHANNEL_MONITOR_TIMER;
 119                         break;
 120                 }
 121                 break;
 122         default:
 123                 goto error;     /* Not implemented */
 124         }
 125
 126         if (snprintf(chan->name, sizeof(chan->name), "%s",
 127                         channel_name) < 0) {
 128                 PERROR("snprintf default channel name");
 129                 goto error;
 130         }
 131         return chan;
 132
 133 error:
 134         free(extended_attr);
 135         free(chan);
 136 error_alloc:
 137         return NULL;
 138 }
 139
 140 void channel_attr_destroy(struct lttng_channel *channel)
 141 {
 142         if (!channel) {
 143                 return;
 144         }
 145         free(channel->attr.extended.ptr);
 146         free(channel);
 147 }
 148
 149 /*
 150  * Disable kernel channel of the kernel session.
 151  */
 152 int channel_kernel_disable(struct ltt_kernel_session *ksession,
 153                 char *channel_name)
 154 {
 155         int ret;
 156         struct ltt_kernel_channel *kchan;
 157
 158         assert(ksession);
 159         assert(channel_name);
 160
 161         kchan = trace_kernel_get_channel_by_name(channel_name, ksession);
 162         if (kchan == NULL) {
 163                 ret = LTTNG_ERR_KERN_CHAN_NOT_FOUND;
 164                 goto error;
 165         }
 166
 167         /* Only if channel is enabled disable it. */
 168         if (kchan->enabled == 1) {
 169                 ret = kernel_disable_channel(kchan);
 170                 if (ret < 0 && ret != -EEXIST) {
 171                         ret = LTTNG_ERR_KERN_CHAN_DISABLE_FAIL;
 172                         goto error;
 173                 }
 174         }
 175
 176         ret = LTTNG_OK;
 177
 178 error:
 179         return ret;
 180 }
 181
 182 /*
 183  * Enable kernel channel of the kernel session.
 184  */
 185 int channel_kernel_enable(struct ltt_kernel_session *ksession,
 186                 struct ltt_kernel_channel *kchan)
 187 {
 188         int ret;
 189
 190         assert(ksession);
 191         assert(kchan);
 192
 193         if (kchan->enabled == 0) {
 194                 ret = kernel_enable_channel(kchan);
 195                 if (ret < 0) {
 196                         ret = LTTNG_ERR_KERN_CHAN_ENABLE_FAIL;
 197                         goto error;
 198                 }
 199         } else {
 200                 ret = LTTNG_ERR_KERN_CHAN_EXIST;
 201                 goto error;
 202         }
 203
 204         ret = LTTNG_OK;
 205
 206 error:
 207         return ret;
 208 }
 209
 210 static int channel_validate(struct lttng_channel *attr)
 211 {
 212         /*
 213          * The ringbuffer (both in user space and kernel) behaves badly
 214          * in overwrite mode and with less than 2 subbuffers so block it
 215          * right away and send back an invalid attribute error.
 216          */
 217         if (attr->attr.overwrite && attr->attr.num_subbuf < 2) {
 218                 return -1;
 219         }
 220         return 0;
 221 }
 222
 223 static int channel_validate_kernel(struct lttng_channel *attr)
 224 {
 225         /* Kernel channels do not support blocking timeout. */
 226         if (((struct lttng_channel_extended *)attr->attr.extended.ptr)->blocking_timeout) {
 227                 return -1;
 228         }
 229         return 0;
 230 }
 231
 232 /*
 233  * Create kernel channel of the kernel session and notify kernel thread.
 234  */
 235 int channel_kernel_create(struct ltt_kernel_session *ksession,
 236                 struct lttng_channel *attr, int kernel_pipe)
 237 {
 238         int ret;
 239         struct lttng_channel *defattr = NULL;
 240
 241         assert(ksession);
 242
 243         /* Creating channel attributes if needed */
 244         if (attr == NULL) {
 245                 defattr = channel_new_default_attr(LTTNG_DOMAIN_KERNEL,
 246                                 LTTNG_BUFFER_GLOBAL);
 247                 if (defattr == NULL) {
 248                         ret = LTTNG_ERR_FATAL;
 249                         goto error;
 250                 }
 251                 attr = defattr;
 252         }
 253
 254         /*
 255          * Set the overwrite mode for this channel based on the session
 256          * type unless the client explicitly overrides the channel mode.
 257          */
 258         if (attr->attr.overwrite == DEFAULT_CHANNEL_OVERWRITE) {
 259                 attr->attr.overwrite = !!ksession->snapshot_mode;
 260         }
 261
 262         /* Validate common channel properties. */
 263         if (channel_validate(attr) < 0) {
 264                 ret = LTTNG_ERR_INVALID;
 265                 goto error;
 266         }
 267
 268         if (channel_validate_kernel(attr) < 0) {
 269                 ret = LTTNG_ERR_INVALID;
 270                 goto error;
 271         }
 272
 273         /* Channel not found, creating it */
 274         ret = kernel_create_channel(ksession, attr);
 275         if (ret < 0) {
 276                 ret = LTTNG_ERR_KERN_CHAN_FAIL;
 277                 goto error;
 278         }
 279
 280         /* Notify kernel thread that there is a new channel */
 281         ret = notify_thread_pipe(kernel_pipe);
 282         if (ret < 0) {
 283                 ret = LTTNG_ERR_FATAL;
 284                 goto error;
 285         }
 286
 287         ret = LTTNG_OK;
 288 error:
 289         channel_attr_destroy(defattr);
 290         return ret;
 291 }
 292
 293 /*
 294  * Enable UST channel for session and domain.
 295  */
 296 int channel_ust_enable(struct ltt_ust_session *usess,
 297                 struct ltt_ust_channel *uchan)
 298 {
 299         int ret = LTTNG_OK;
 300
 301         assert(usess);
 302         assert(uchan);
 303
 304         /* If already enabled, everything is OK */
 305         if (uchan->enabled) {
 306                 DBG3("Channel %s already enabled. Skipping", uchan->name);
 307                 ret = LTTNG_ERR_UST_CHAN_EXIST;
 308                 goto end;
 309         } else {
 310                 uchan->enabled = 1;
 311                 DBG2("Channel %s enabled successfully", uchan->name);
 312         }
 313
 314         if (!usess->active) {
 315                 /*
 316                  * The channel will be activated against the apps
 317                  * when the session is started as part of the
 318                  * application channel "synchronize" operation.
 319                  */
 320                 goto end;
 321         }
 322
 323         DBG2("Channel %s being enabled in UST domain", uchan->name);
 324
 325         /*
 326          * Enable channel for UST global domain on all applications. Ignore return
 327          * value here since whatever error we got, it means that the channel was
 328          * not created on one or many registered applications and we can not report
 329          * this to the user yet. However, at this stage, the channel was
 330          * successfully created on the session daemon side so the enable-channel
 331          * command is a success.
 332          */
 333         (void) ust_app_enable_channel_glb(usess, uchan);
 334
 335
 336 end:
 337         return ret;
 338 }
 339
 340 /*
 341  * Create UST channel for session and domain.
 342  */
 343 int channel_ust_create(struct ltt_ust_session *usess,
 344                 struct lttng_channel *attr, enum lttng_buffer_type type)
 345 {
 346         int ret = LTTNG_OK;
 347         struct ltt_ust_channel *uchan = NULL;
 348         struct lttng_channel *defattr = NULL;
 349         enum lttng_domain_type domain = LTTNG_DOMAIN_UST;
 350         bool chan_published = false;
 351
 352         assert(usess);
 353
 354         /* Creating channel attributes if needed */
 355         if (attr == NULL) {
 356                 defattr = channel_new_default_attr(LTTNG_DOMAIN_UST, type);
 357                 if (defattr == NULL) {
 358                         ret = LTTNG_ERR_FATAL;
 359                         goto error;
 360                 }
 361                 attr = defattr;
 362         } else {
 363                 /*
 364                  * HACK: Set the channel's subdomain (JUL, Log4j, Python, etc.)
 365                  * based on the default name.
 366                  */
 367                 if (!strcmp(attr->name, DEFAULT_JUL_CHANNEL_NAME)) {
 368                         domain = LTTNG_DOMAIN_JUL;
 369                 } else if (!strcmp(attr->name, DEFAULT_LOG4J_CHANNEL_NAME)) {
 370                         domain = LTTNG_DOMAIN_LOG4J;
 371                 } else if (!strcmp(attr->name, DEFAULT_PYTHON_CHANNEL_NAME)) {
 372                         domain = LTTNG_DOMAIN_PYTHON;
 373                 }
 374         }
 375
 376         /*
 377          * Set the overwrite mode for this channel based on the session
 378          * type unless the client explicitly overrides the channel mode.
 379          */
 380         if (attr->attr.overwrite == DEFAULT_CHANNEL_OVERWRITE) {
 381                 attr->attr.overwrite = !!usess->snapshot_mode;
 382         }
 383
 384         /* Enforce mmap output for snapshot sessions. */
 385         if (usess->snapshot_mode) {
 386                 attr->attr.output = LTTNG_EVENT_MMAP;
 387         }
 388
 389         /* Validate common channel properties. */
 390         if (channel_validate(attr) < 0) {
 391                 ret = LTTNG_ERR_INVALID;
 392                 goto error;
 393         }
 394
 395         /*
 396          * Validate UST buffer size and number of buffers: must both be power of 2
 397          * and nonzero. We validate right here for UST, because applications will
 398          * not report the error to the user (unlike kernel tracing).
 399          */
 400         if (!attr->attr.subbuf_size ||
 401                         (attr->attr.subbuf_size & (attr->attr.subbuf_size - 1))) {
 402                 ret = LTTNG_ERR_INVALID;
 403                 goto error;
 404         }
 405
 406         /*
 407          * Invalid subbuffer size if it's lower then the page size.
 408          */
 409         if (attr->attr.subbuf_size < page_size) {
 410                 ret = LTTNG_ERR_INVALID;
 411                 goto error;
 412         }
 413
 414         if (!attr->attr.num_subbuf ||
 415                         (attr->attr.num_subbuf & (attr->attr.num_subbuf - 1))) {
 416                 ret = LTTNG_ERR_INVALID;
 417                 goto error;
 418         }
 419
 420         if (attr->attr.output != LTTNG_EVENT_MMAP) {
 421                 ret = LTTNG_ERR_NOT_SUPPORTED;
 422                 goto error;
 423         }
 424
 425         /*
 426          * The tracefile_size should not be < to the subbuf_size, otherwise
 427          * we won't be able to write the packets on disk
 428          */
 429         if ((attr->attr.tracefile_size > 0) &&
 430                         (attr->attr.tracefile_size < attr->attr.subbuf_size)) {
 431                 ret = LTTNG_ERR_INVALID;
 432                 goto error;
 433         }
 434
 435         /* Validate buffer type. */
 436         switch (type) {
 437         case LTTNG_BUFFER_PER_PID:
 438                 break;
 439         case LTTNG_BUFFER_PER_UID:
 440                 break;
 441         default:
 442                 ret = LTTNG_ERR_BUFFER_NOT_SUPPORTED;
 443                 goto error;
 444         }
 445
 446         /* Create UST channel */
 447         uchan = trace_ust_create_channel(attr, domain);
 448         if (uchan == NULL) {
 449                 ret = LTTNG_ERR_FATAL;
 450                 goto error;
 451         }
 452
 453         uchan->enabled = 1;
 454         if (trace_ust_is_max_id(usess->used_channel_id)) {
 455                 ret = LTTNG_ERR_UST_CHAN_FAIL;
 456                 goto error;
 457         }
 458         uchan->id = trace_ust_get_next_chan_id(usess);
 459
 460         DBG2("Channel %s is being created for UST with buffer %d and id %" PRIu64,
 461                         uchan->name, type, uchan->id);
 462
 463         /* Flag session buffer type. */
 464         if (!usess->buffer_type_changed) {
 465                 usess->buffer_type = type;
 466                 usess->buffer_type_changed = 1;
 467         } else if (usess->buffer_type != type) {
 468                 /* Buffer type was already set. Refuse to create channel. */
 469                 ret = LTTNG_ERR_BUFFER_TYPE_MISMATCH;
 470                 goto error_free_chan;
 471         }
 472
 473         if (usess->active) {
 474                 /* Enable channel for global domain */
 475                 ret = ust_app_create_channel_glb(usess, uchan);
 476                 if (ret < 0 && ret != -LTTNG_UST_ERR_EXIST) {
 477                         ret = LTTNG_ERR_UST_CHAN_FAIL;
 478                         goto error_free_chan;
 479                 }
 480         }
 481
 482         /* Adding the channel to the channel hash table. */
 483         rcu_read_lock();
 484         if (strncmp(uchan->name, DEFAULT_METADATA_NAME,
 485                                 sizeof(uchan->name))) {
 486                 lttng_ht_add_unique_str(usess->domain_global.channels, &uchan->node);
 487                 chan_published = true;
 488         } else {
 489                 /*
 490                  * Copy channel attribute to session if this is metadata so if NO
 491                  * application exists we can access that data in the shadow copy during
 492                  * the global update of newly registered application.
 493                  */
 494                 memcpy(&usess->metadata_attr, &uchan->attr,
 495                                 sizeof(usess->metadata_attr));
 496         }
 497         rcu_read_unlock();
 498
 499         DBG2("Channel %s created successfully", uchan->name);
 500         if (domain != LTTNG_DOMAIN_UST) {
 501                 struct agent *agt = trace_ust_find_agent(usess, domain);
 502
 503                 if (!agt) {
 504                         agt = agent_create(domain);
 505                         if (!agt) {
 506                                 ret = LTTNG_ERR_NOMEM;
 507                                 goto error_remove_chan;
 508                         }
 509                         agent_add(agt, usess->agents);
 510                 }
 511         }
 512
 513         channel_attr_destroy(defattr);
 514         return LTTNG_OK;
 515
 516 error_remove_chan:
 517         if (chan_published) {
 518                 trace_ust_delete_channel(usess->domain_global.channels, uchan);
 519         }
 520 error_free_chan:
 521         trace_ust_destroy_channel(uchan);
 522 error:
 523         channel_attr_destroy(defattr);
 524         return ret;
 525 }
 526
 527 /*
 528  * Disable UST channel for session and domain.
 529  */
 530 int channel_ust_disable(struct ltt_ust_session *usess,
 531                 struct ltt_ust_channel *uchan)
 532 {
 533         int ret = LTTNG_OK;
 534
 535         assert(usess);
 536         assert(uchan);
 537
 538         /* Already disabled */
 539         if (uchan->enabled == 0) {
 540                 DBG2("Channel UST %s already disabled", uchan->name);
 541                 goto end;
 542         }
 543         if (!usess->active) {
 544                 goto end;
 545         }
 546
 547         DBG2("Channel %s being disabled in UST global domain", uchan->name);
 548         /* Disable channel for global domain */
 549         ret = ust_app_disable_channel_glb(usess, uchan);
 550         if (ret < 0 && ret != -LTTNG_UST_ERR_EXIST) {
 551                 ret = LTTNG_ERR_UST_CHAN_DISABLE_FAIL;
 552                 goto error;
 553         }
 554
 555         uchan->enabled = 0;
 556
 557         DBG2("Channel %s disabled successfully", uchan->name);
 558
 559         return LTTNG_OK;
 560
 561 end:
 562 error:
 563         return ret;
 564 }