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