src/bin/lttng-sessiond/channel.cpp

   1 /*
   2  * Copyright (C) 2011 David Goulet <david.goulet@polymtl.ca>
   3  * Copyright (C) 2016 Jérémie Galarneau <jeremie.galarneau@efficios.com>
   4  *
   5  * SPDX-License-Identifier: GPL-2.0-only
   6  *
   7  */
   8
   9 #define _LGPL_SOURCE
  10 #include <inttypes.h>
  11 #include <string.h>
  12 #include <unistd.h>
  13
  14 #include <common/common.h>
  15 #include <common/defaults.h>
  16 #include <common/sessiond-comm/sessiond-comm.h>
  17
  18 #include "channel.h"
  19 #include "lttng-sessiond.h"
  20 #include "kernel.h"
  21 #include "lttng-ust-ctl.h"
  22 #include "lttng-ust-error.h"
  23 #include "utils.h"
  24 #include "ust-app.h"
  25 #include "agent.h"
  26
  27 /*
  28  * Return allocated channel attributes.
  29  */
  30 struct lttng_channel *channel_new_default_attr(int dom,
  31                 enum lttng_buffer_type type)
  32 {
  33         struct lttng_channel *chan;
  34         const char *channel_name = DEFAULT_CHANNEL_NAME;
  35         struct lttng_channel_extended *extended_attr = NULL;
  36
  37         chan = (lttng_channel *) zmalloc(sizeof(struct lttng_channel));
  38         if (chan == NULL) {
  39                 PERROR("zmalloc channel init");
  40                 goto error_alloc;
  41         }
  42
  43         extended_attr = (lttng_channel_extended *) zmalloc(sizeof(struct lttng_channel_extended));
  44         if (!extended_attr) {
  45                 PERROR("zmalloc channel extended init");
  46                 goto error;
  47         }
  48
  49         chan->attr.extended.ptr = extended_attr;
  50
  51         /* Same for all domains. */
  52         chan->attr.overwrite = DEFAULT_CHANNEL_OVERWRITE;
  53         chan->attr.tracefile_size = DEFAULT_CHANNEL_TRACEFILE_SIZE;
  54         chan->attr.tracefile_count = DEFAULT_CHANNEL_TRACEFILE_COUNT;
  55
  56         switch (dom) {
  57         case LTTNG_DOMAIN_KERNEL:
  58                 LTTNG_ASSERT(type == LTTNG_BUFFER_GLOBAL);
  59                 chan->attr.subbuf_size =
  60                         default_get_kernel_channel_subbuf_size();
  61                 chan->attr.num_subbuf = DEFAULT_KERNEL_CHANNEL_SUBBUF_NUM;
  62                 chan->attr.output = DEFAULT_KERNEL_CHANNEL_OUTPUT;
  63                 chan->attr.switch_timer_interval = DEFAULT_KERNEL_CHANNEL_SWITCH_TIMER;
  64                 chan->attr.read_timer_interval = DEFAULT_KERNEL_CHANNEL_READ_TIMER;
  65                 chan->attr.live_timer_interval = DEFAULT_KERNEL_CHANNEL_LIVE_TIMER;
  66                 extended_attr->blocking_timeout = DEFAULT_KERNEL_CHANNEL_BLOCKING_TIMEOUT;
  67                 extended_attr->monitor_timer_interval =
  68                         DEFAULT_KERNEL_CHANNEL_MONITOR_TIMER;
  69                 break;
  70         case LTTNG_DOMAIN_JUL:
  71                 channel_name = DEFAULT_JUL_CHANNEL_NAME;
  72                 goto common_ust;
  73         case LTTNG_DOMAIN_LOG4J:
  74                 channel_name = DEFAULT_LOG4J_CHANNEL_NAME;
  75                 goto common_ust;
  76         case LTTNG_DOMAIN_PYTHON:
  77                 channel_name = DEFAULT_PYTHON_CHANNEL_NAME;
  78                 goto common_ust;
  79         case LTTNG_DOMAIN_UST:
  80 common_ust:
  81                 switch (type) {
  82                 case LTTNG_BUFFER_PER_UID:
  83                         chan->attr.subbuf_size = default_get_ust_uid_channel_subbuf_size();
  84                         chan->attr.num_subbuf = DEFAULT_UST_UID_CHANNEL_SUBBUF_NUM;
  85                         chan->attr.output = DEFAULT_UST_UID_CHANNEL_OUTPUT;
  86                         chan->attr.switch_timer_interval =
  87                                 DEFAULT_UST_UID_CHANNEL_SWITCH_TIMER;
  88                         chan->attr.read_timer_interval =
  89                                 DEFAULT_UST_UID_CHANNEL_READ_TIMER;
  90                         chan->attr.live_timer_interval =
  91                                 DEFAULT_UST_UID_CHANNEL_LIVE_TIMER;
  92                         extended_attr->blocking_timeout = DEFAULT_UST_UID_CHANNEL_BLOCKING_TIMEOUT;
  93                         extended_attr->monitor_timer_interval =
  94                                 DEFAULT_UST_UID_CHANNEL_MONITOR_TIMER;
  95                         break;
  96                 case LTTNG_BUFFER_PER_PID:
  97                 default:
  98                         chan->attr.subbuf_size = default_get_ust_pid_channel_subbuf_size();
  99                         chan->attr.num_subbuf = DEFAULT_UST_PID_CHANNEL_SUBBUF_NUM;
 100                         chan->attr.output = DEFAULT_UST_PID_CHANNEL_OUTPUT;
 101                         chan->attr.switch_timer_interval =
 102                                 DEFAULT_UST_PID_CHANNEL_SWITCH_TIMER;
 103                         chan->attr.read_timer_interval =
 104                                 DEFAULT_UST_PID_CHANNEL_READ_TIMER;
 105                         chan->attr.live_timer_interval =
 106                                 DEFAULT_UST_PID_CHANNEL_LIVE_TIMER;
 107                         extended_attr->blocking_timeout = DEFAULT_UST_PID_CHANNEL_BLOCKING_TIMEOUT;
 108                         extended_attr->monitor_timer_interval =
 109                                 DEFAULT_UST_PID_CHANNEL_MONITOR_TIMER;
 110                         break;
 111                 }
 112                 break;
 113         default:
 114                 goto error;     /* Not implemented */
 115         }
 116
 117         if (snprintf(chan->name, sizeof(chan->name), "%s",
 118                         channel_name) < 0) {
 119                 PERROR("snprintf default channel name");
 120                 goto error;
 121         }
 122         return chan;
 123
 124 error:
 125         free(extended_attr);
 126         free(chan);
 127 error_alloc:
 128         return NULL;
 129 }
 130
 131 void channel_attr_destroy(struct lttng_channel *channel)
 132 {
 133         if (!channel) {
 134                 return;
 135         }
 136         free(channel->attr.extended.ptr);
 137         free(channel);
 138 }
 139
 140 /*
 141  * Disable kernel channel of the kernel session.
 142  */
 143 int channel_kernel_disable(struct ltt_kernel_session *ksession,
 144                 char *channel_name)
 145 {
 146         int ret;
 147         struct ltt_kernel_channel *kchan;
 148
 149         LTTNG_ASSERT(ksession);
 150         LTTNG_ASSERT(channel_name);
 151
 152         kchan = trace_kernel_get_channel_by_name(channel_name, ksession);
 153         if (kchan == NULL) {
 154                 ret = LTTNG_ERR_KERN_CHAN_NOT_FOUND;
 155                 goto error;
 156         }
 157
 158         /* Only if channel is enabled disable it. */
 159         if (kchan->enabled == 1) {
 160                 ret = kernel_disable_channel(kchan);
 161                 if (ret < 0 && ret != -EEXIST) {
 162                         ret = LTTNG_ERR_KERN_CHAN_DISABLE_FAIL;
 163                         goto error;
 164                 }
 165         }
 166
 167         ret = LTTNG_OK;
 168
 169 error:
 170         return ret;
 171 }
 172
 173 /*
 174  * Enable kernel channel of the kernel session.
 175  */
 176 int channel_kernel_enable(struct ltt_kernel_session *ksession,
 177                 struct ltt_kernel_channel *kchan)
 178 {
 179         int ret;
 180
 181         LTTNG_ASSERT(ksession);
 182         LTTNG_ASSERT(kchan);
 183
 184         if (kchan->enabled == 0) {
 185                 ret = kernel_enable_channel(kchan);
 186                 if (ret < 0) {
 187                         ret = LTTNG_ERR_KERN_CHAN_ENABLE_FAIL;
 188                         goto error;
 189                 }
 190         } else {
 191                 ret = LTTNG_ERR_KERN_CHAN_EXIST;
 192                 goto error;
 193         }
 194
 195         ret = LTTNG_OK;
 196
 197 error:
 198         return ret;
 199 }
 200
 201 static int channel_validate(struct lttng_channel *attr)
 202 {
 203         /*
 204          * The ringbuffer (both in user space and kernel) behaves badly
 205          * in overwrite mode and with less than 2 subbuffers so block it
 206          * right away and send back an invalid attribute error.
 207          */
 208         if (attr->attr.overwrite && attr->attr.num_subbuf < 2) {
 209                 return -1;
 210         }
 211         return 0;
 212 }
 213
 214 static int channel_validate_kernel(struct lttng_channel *attr)
 215 {
 216         /* Kernel channels do not support blocking timeout. */
 217         if (((struct lttng_channel_extended *)attr->attr.extended.ptr)->blocking_timeout) {
 218                 return -1;
 219         }
 220         return 0;
 221 }
 222
 223 /*
 224  * Create kernel channel of the kernel session and notify kernel thread.
 225  */
 226 int channel_kernel_create(struct ltt_kernel_session *ksession,
 227                 struct lttng_channel *attr, int kernel_pipe)
 228 {
 229         int ret;
 230         struct lttng_channel *defattr = NULL;
 231
 232         LTTNG_ASSERT(ksession);
 233
 234         /* Creating channel attributes if needed */
 235         if (attr == NULL) {
 236                 defattr = channel_new_default_attr(LTTNG_DOMAIN_KERNEL,
 237                                 LTTNG_BUFFER_GLOBAL);
 238                 if (defattr == NULL) {
 239                         ret = LTTNG_ERR_FATAL;
 240                         goto error;
 241                 }
 242                 attr = defattr;
 243         }
 244
 245         /*
 246          * Set the overwrite mode for this channel based on the session
 247          * type unless the client explicitly overrides the channel mode.
 248          */
 249         if (attr->attr.overwrite == DEFAULT_CHANNEL_OVERWRITE) {
 250                 attr->attr.overwrite = !!ksession->snapshot_mode;
 251         }
 252
 253         /* Validate common channel properties. */
 254         if (channel_validate(attr) < 0) {
 255                 ret = LTTNG_ERR_INVALID;
 256                 goto error;
 257         }
 258
 259         if (channel_validate_kernel(attr) < 0) {
 260                 ret = LTTNG_ERR_INVALID;
 261                 goto error;
 262         }
 263
 264         /* Channel not found, creating it */
 265         ret = kernel_create_channel(ksession, attr);
 266         if (ret < 0) {
 267                 ret = LTTNG_ERR_KERN_CHAN_FAIL;
 268                 goto error;
 269         }
 270
 271         /* Notify kernel thread that there is a new channel */
 272         ret = notify_thread_pipe(kernel_pipe);
 273         if (ret < 0) {
 274                 ret = LTTNG_ERR_FATAL;
 275                 goto error;
 276         }
 277
 278         ret = LTTNG_OK;
 279 error:
 280         channel_attr_destroy(defattr);
 281         return ret;
 282 }
 283
 284 /*
 285  * Enable UST channel for session and domain.
 286  */
 287 int channel_ust_enable(struct ltt_ust_session *usess,
 288                 struct ltt_ust_channel *uchan)
 289 {
 290         int ret = LTTNG_OK;
 291
 292         LTTNG_ASSERT(usess);
 293         LTTNG_ASSERT(uchan);
 294
 295         /* If already enabled, everything is OK */
 296         if (uchan->enabled) {
 297                 DBG3("Channel %s already enabled. Skipping", uchan->name);
 298                 ret = LTTNG_ERR_UST_CHAN_EXIST;
 299                 goto end;
 300         } else {
 301                 uchan->enabled = 1;
 302                 DBG2("Channel %s enabled successfully", uchan->name);
 303         }
 304
 305         if (!usess->active) {
 306                 /*
 307                  * The channel will be activated against the apps
 308                  * when the session is started as part of the
 309                  * application channel "synchronize" operation.
 310                  */
 311                 goto end;
 312         }
 313
 314         DBG2("Channel %s being enabled in UST domain", uchan->name);
 315
 316         /*
 317          * Enable channel for UST global domain on all applications. Ignore return
 318          * value here since whatever error we got, it means that the channel was
 319          * not created on one or many registered applications and we can not report
 320          * this to the user yet. However, at this stage, the channel was
 321          * successfully created on the session daemon side so the enable-channel
 322          * command is a success.
 323          */
 324         (void) ust_app_enable_channel_glb(usess, uchan);
 325
 326
 327 end:
 328         return ret;
 329 }
 330
 331 /*
 332  * Create UST channel for session and domain.
 333  */
 334 int channel_ust_create(struct ltt_ust_session *usess,
 335                 struct lttng_channel *attr, enum lttng_buffer_type type)
 336 {
 337         int ret = LTTNG_OK;
 338         struct ltt_ust_channel *uchan = NULL;
 339         struct lttng_channel *defattr = NULL;
 340         enum lttng_domain_type domain = LTTNG_DOMAIN_UST;
 341         bool chan_published = false;
 342
 343         LTTNG_ASSERT(usess);
 344
 345         /* Creating channel attributes if needed */
 346         if (attr == NULL) {
 347                 defattr = channel_new_default_attr(LTTNG_DOMAIN_UST, type);
 348                 if (defattr == NULL) {
 349                         ret = LTTNG_ERR_FATAL;
 350                         goto error;
 351                 }
 352                 attr = defattr;
 353         } else {
 354                 /*
 355                  * HACK: Set the channel's subdomain (JUL, Log4j, Python, etc.)
 356                  * based on the default name.
 357                  */
 358                 if (!strcmp(attr->name, DEFAULT_JUL_CHANNEL_NAME)) {
 359                         domain = LTTNG_DOMAIN_JUL;
 360                 } else if (!strcmp(attr->name, DEFAULT_LOG4J_CHANNEL_NAME)) {
 361                         domain = LTTNG_DOMAIN_LOG4J;
 362                 } else if (!strcmp(attr->name, DEFAULT_PYTHON_CHANNEL_NAME)) {
 363                         domain = LTTNG_DOMAIN_PYTHON;
 364                 }
 365         }
 366
 367         /*
 368          * Set the overwrite mode for this channel based on the session
 369          * type unless the client explicitly overrides the channel mode.
 370          */
 371         if (attr->attr.overwrite == DEFAULT_CHANNEL_OVERWRITE) {
 372                 attr->attr.overwrite = !!usess->snapshot_mode;
 373         }
 374
 375         /* Enforce mmap output for snapshot sessions. */
 376         if (usess->snapshot_mode) {
 377                 attr->attr.output = LTTNG_EVENT_MMAP;
 378         }
 379
 380         /* Validate common channel properties. */
 381         if (channel_validate(attr) < 0) {
 382                 ret = LTTNG_ERR_INVALID;
 383                 goto error;
 384         }
 385
 386         /*
 387          * Validate UST buffer size and number of buffers: must both be power of 2
 388          * and nonzero. We validate right here for UST, because applications will
 389          * not report the error to the user (unlike kernel tracing).
 390          */
 391         if (!attr->attr.subbuf_size ||
 392                         (attr->attr.subbuf_size & (attr->attr.subbuf_size - 1))) {
 393                 ret = LTTNG_ERR_INVALID;
 394                 goto error;
 395         }
 396
 397         /*
 398          * Invalid subbuffer size if it's lower then the page size.
 399          */
 400         if (attr->attr.subbuf_size < the_page_size) {
 401                 ret = LTTNG_ERR_INVALID;
 402                 goto error;
 403         }
 404
 405         if (!attr->attr.num_subbuf ||
 406                         (attr->attr.num_subbuf & (attr->attr.num_subbuf - 1))) {
 407                 ret = LTTNG_ERR_INVALID;
 408                 goto error;
 409         }
 410
 411         if (attr->attr.output != LTTNG_EVENT_MMAP) {
 412                 ret = LTTNG_ERR_NOT_SUPPORTED;
 413                 goto error;
 414         }
 415
 416         /*
 417          * The tracefile_size should not be < to the subbuf_size, otherwise
 418          * we won't be able to write the packets on disk
 419          */
 420         if ((attr->attr.tracefile_size > 0) &&
 421                         (attr->attr.tracefile_size < attr->attr.subbuf_size)) {
 422                 ret = LTTNG_ERR_INVALID;
 423                 goto error;
 424         }
 425
 426         /* Validate buffer type. */
 427         switch (type) {
 428         case LTTNG_BUFFER_PER_PID:
 429                 break;
 430         case LTTNG_BUFFER_PER_UID:
 431                 break;
 432         default:
 433                 ret = LTTNG_ERR_BUFFER_NOT_SUPPORTED;
 434                 goto error;
 435         }
 436
 437         /* Create UST channel */
 438         uchan = trace_ust_create_channel(attr, domain);
 439         if (uchan == NULL) {
 440                 ret = LTTNG_ERR_FATAL;
 441                 goto error;
 442         }
 443
 444         uchan->enabled = 1;
 445         if (trace_ust_is_max_id(usess->used_channel_id)) {
 446                 ret = LTTNG_ERR_UST_CHAN_FAIL;
 447                 goto error;
 448         }
 449         uchan->id = trace_ust_get_next_chan_id(usess);
 450
 451         DBG2("Channel %s is being created for UST with buffer %d and id %" PRIu64,
 452                         uchan->name, type, uchan->id);
 453
 454         /* Flag session buffer type. */
 455         if (!usess->buffer_type_changed) {
 456                 usess->buffer_type = type;
 457                 usess->buffer_type_changed = 1;
 458         } else if (usess->buffer_type != type) {
 459                 /* Buffer type was already set. Refuse to create channel. */
 460                 ret = LTTNG_ERR_BUFFER_TYPE_MISMATCH;
 461                 goto error_free_chan;
 462         }
 463
 464         /* Adding the channel to the channel hash table. */
 465         rcu_read_lock();
 466         if (strncmp(uchan->name, DEFAULT_METADATA_NAME,
 467                                 sizeof(uchan->name))) {
 468                 lttng_ht_add_unique_str(usess->domain_global.channels, &uchan->node);
 469                 chan_published = true;
 470         } else {
 471                 /*
 472                  * Copy channel attribute to session if this is metadata so if NO
 473                  * application exists we can access that data in the shadow copy during
 474                  * the global update of newly registered application.
 475                  */
 476                 memcpy(&usess->metadata_attr, &uchan->attr,
 477                                 sizeof(usess->metadata_attr));
 478         }
 479         rcu_read_unlock();
 480
 481         DBG2("Channel %s created successfully", uchan->name);
 482         if (domain != LTTNG_DOMAIN_UST) {
 483                 struct agent *agt = trace_ust_find_agent(usess, domain);
 484
 485                 if (!agt) {
 486                         agt = agent_create(domain);
 487                         if (!agt) {
 488                                 ret = LTTNG_ERR_NOMEM;
 489                                 goto error_remove_chan;
 490                         }
 491                         agent_add(agt, usess->agents);
 492                 }
 493         }
 494
 495         channel_attr_destroy(defattr);
 496         return LTTNG_OK;
 497
 498 error_remove_chan:
 499         if (chan_published) {
 500                 trace_ust_delete_channel(usess->domain_global.channels, uchan);
 501         }
 502 error_free_chan:
 503         trace_ust_destroy_channel(uchan);
 504 error:
 505         channel_attr_destroy(defattr);
 506         return ret;
 507 }
 508
 509 /*
 510  * Disable UST channel for session and domain.
 511  */
 512 int channel_ust_disable(struct ltt_ust_session *usess,
 513                 struct ltt_ust_channel *uchan)
 514 {
 515         int ret = LTTNG_OK;
 516
 517         LTTNG_ASSERT(usess);
 518         LTTNG_ASSERT(uchan);
 519
 520         /* Already disabled */
 521         if (uchan->enabled == 0) {
 522                 DBG2("Channel UST %s already disabled", uchan->name);
 523                 goto end;
 524         }
 525
 526         uchan->enabled = 0;
 527
 528         /*
 529          * If session is inactive we don't notify the tracer right away. We
 530          * wait for the next synchronization.
 531          */
 532         if (!usess->active) {
 533                 goto end;
 534         }
 535
 536         DBG2("Channel %s being disabled in UST global domain", uchan->name);
 537         /* Disable channel for global domain */
 538         ret = ust_app_disable_channel_glb(usess, uchan);
 539         if (ret < 0 && ret != -LTTNG_UST_ERR_EXIST) {
 540                 ret = LTTNG_ERR_UST_CHAN_DISABLE_FAIL;
 541                 goto error;
 542         }
 543
 544         DBG2("Channel %s disabled successfully", uchan->name);
 545
 546         return LTTNG_OK;
 547
 548 end:
 549 error:
 550         return ret;
 551 }