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         /* Enforce mmap output for snapshot sessions. */
 263         if (ksession->snapshot_mode) {
 264                 attr->attr.output = LTTNG_EVENT_MMAP;
 265         }
 266
 267         /* Validate common channel properties. */
 268         if (channel_validate(attr) < 0) {
 269                 ret = LTTNG_ERR_INVALID;
 270                 goto error;
 271         }
 272
 273         if (channel_validate_kernel(attr) < 0) {
 274                 ret = LTTNG_ERR_INVALID;
 275                 goto error;
 276         }
 277
 278         /* Channel not found, creating it */
 279         ret = kernel_create_channel(ksession, attr);
 280         if (ret < 0) {
 281                 ret = LTTNG_ERR_KERN_CHAN_FAIL;
 282                 goto error;
 283         }
 284
 285         /* Notify kernel thread that there is a new channel */
 286         ret = notify_thread_pipe(kernel_pipe);
 287         if (ret < 0) {
 288                 ret = LTTNG_ERR_FATAL;
 289                 goto error;
 290         }
 291
 292         ret = LTTNG_OK;
 293 error:
 294         channel_attr_destroy(defattr);
 295         return ret;
 296 }
 297
 298 /*
 299  * Enable UST channel for session and domain.
 300  */
 301 int channel_ust_enable(struct ltt_ust_session *usess,
 302                 struct ltt_ust_channel *uchan)
 303 {
 304         int ret = LTTNG_OK;
 305
 306         assert(usess);
 307         assert(uchan);
 308
 309         /* If already enabled, everything is OK */
 310         if (uchan->enabled) {
 311                 DBG3("Channel %s already enabled. Skipping", uchan->name);
 312                 ret = LTTNG_ERR_UST_CHAN_EXIST;
 313                 goto end;
 314         }
 315
 316         DBG2("Channel %s being enabled in UST domain", uchan->name);
 317
 318         /*
 319          * Enable channel for UST global domain on all applications. Ignore return
 320          * value here since whatever error we got, it means that the channel was
 321          * not created on one or many registered applications and we can not report
 322          * this to the user yet. However, at this stage, the channel was
 323          * successfully created on the session daemon side so the enable-channel
 324          * command is a success.
 325          */
 326         (void) ust_app_enable_channel_glb(usess, uchan);
 327
 328         uchan->enabled = 1;
 329         DBG2("Channel %s enabled successfully", uchan->name);
 330
 331 end:
 332         return ret;
 333 }
 334
 335 /*
 336  * Create UST channel for session and domain.
 337  */
 338 int channel_ust_create(struct ltt_ust_session *usess,
 339                 struct lttng_channel *attr, enum lttng_buffer_type type)
 340 {
 341         int ret = LTTNG_OK;
 342         struct ltt_ust_channel *uchan = NULL;
 343         struct lttng_channel *defattr = NULL;
 344         enum lttng_domain_type domain = LTTNG_DOMAIN_UST;
 345
 346         assert(usess);
 347
 348         /* Creating channel attributes if needed */
 349         if (attr == NULL) {
 350                 defattr = channel_new_default_attr(LTTNG_DOMAIN_UST, type);
 351                 if (defattr == NULL) {
 352                         ret = LTTNG_ERR_FATAL;
 353                         goto error;
 354                 }
 355                 attr = defattr;
 356         } else {
 357                 /*
 358                  * HACK: Set the channel's subdomain (JUL, Log4j, Python, etc.)
 359                  * based on the default name.
 360                  */
 361                 if (!strcmp(attr->name, DEFAULT_JUL_CHANNEL_NAME)) {
 362                         domain = LTTNG_DOMAIN_JUL;
 363                 } else if (!strcmp(attr->name, DEFAULT_LOG4J_CHANNEL_NAME)) {
 364                         domain = LTTNG_DOMAIN_LOG4J;
 365                 } else if (!strcmp(attr->name, DEFAULT_PYTHON_CHANNEL_NAME)) {
 366                         domain = LTTNG_DOMAIN_PYTHON;
 367                 }
 368         }
 369
 370         /*
 371          * Set the overwrite mode for this channel based on the session
 372          * type unless the client explicitly overrides the channel mode.
 373          */
 374         if (attr->attr.overwrite == DEFAULT_CHANNEL_OVERWRITE) {
 375                 attr->attr.overwrite = !!usess->snapshot_mode;
 376         }
 377
 378         /* Enforce mmap output for snapshot sessions. */
 379         if (usess->snapshot_mode) {
 380                 attr->attr.output = LTTNG_EVENT_MMAP;
 381         }
 382
 383         /* Validate common channel properties. */
 384         if (channel_validate(attr) < 0) {
 385                 ret = LTTNG_ERR_INVALID;
 386                 goto error;
 387         }
 388
 389         /*
 390          * Validate UST buffer size and number of buffers: must both be power of 2
 391          * and nonzero. We validate right here for UST, because applications will
 392          * not report the error to the user (unlike kernel tracing).
 393          */
 394         if (!attr->attr.subbuf_size ||
 395                         (attr->attr.subbuf_size & (attr->attr.subbuf_size - 1))) {
 396                 ret = LTTNG_ERR_INVALID;
 397                 goto error;
 398         }
 399
 400         /*
 401          * Invalid subbuffer size if it's lower then the page size.
 402          */
 403         if (attr->attr.subbuf_size < page_size) {
 404                 ret = LTTNG_ERR_INVALID;
 405                 goto error;
 406         }
 407
 408         if (!attr->attr.num_subbuf ||
 409                         (attr->attr.num_subbuf & (attr->attr.num_subbuf - 1))) {
 410                 ret = LTTNG_ERR_INVALID;
 411                 goto error;
 412         }
 413
 414         if (attr->attr.output != LTTNG_EVENT_MMAP) {
 415                 ret = LTTNG_ERR_NOT_SUPPORTED;
 416                 goto error;
 417         }
 418
 419         /*
 420          * The tracefile_size should not be < to the subbuf_size, otherwise
 421          * we won't be able to write the packets on disk
 422          */
 423         if ((attr->attr.tracefile_size > 0) &&
 424                         (attr->attr.tracefile_size < attr->attr.subbuf_size)) {
 425                 ret = LTTNG_ERR_INVALID;
 426                 goto error;
 427         }
 428
 429         /* Validate buffer type. */
 430         switch (type) {
 431         case LTTNG_BUFFER_PER_PID:
 432                 break;
 433         case LTTNG_BUFFER_PER_UID:
 434                 break;
 435         default:
 436                 ret = LTTNG_ERR_BUFFER_NOT_SUPPORTED;
 437                 goto error;
 438         }
 439
 440         /* Create UST channel */
 441         uchan = trace_ust_create_channel(attr, domain);
 442         if (uchan == NULL) {
 443                 ret = LTTNG_ERR_FATAL;
 444                 goto error;
 445         }
 446
 447         uchan->enabled = 1;
 448         if (trace_ust_is_max_id(usess->used_channel_id)) {
 449                 ret = LTTNG_ERR_UST_CHAN_FAIL;
 450                 goto error;
 451         }
 452         uchan->id = trace_ust_get_next_chan_id(usess);
 453
 454         DBG2("Channel %s is being created for UST with buffer %d and id %" PRIu64,
 455                         uchan->name, type, uchan->id);
 456
 457         /* Flag session buffer type. */
 458         if (!usess->buffer_type_changed) {
 459                 usess->buffer_type = type;
 460                 usess->buffer_type_changed = 1;
 461         } else if (usess->buffer_type != type) {
 462                 /* Buffer type was already set. Refuse to create channel. */
 463                 ret = LTTNG_ERR_BUFFER_TYPE_MISMATCH;
 464                 goto error_free_chan;
 465         }
 466
 467         /* Enable channel for global domain */
 468         ret = ust_app_create_channel_glb(usess, uchan);
 469         if (ret < 0 && ret != -LTTNG_UST_ERR_EXIST) {
 470                 ret = LTTNG_ERR_UST_CHAN_FAIL;
 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         } else {
 480                 /*
 481                  * Copy channel attribute to session if this is metadata so if NO
 482                  * application exists we can access that data in the shadow copy during
 483                  * the global update of newly registered application.
 484                  */
 485                 memcpy(&usess->metadata_attr, &uchan->attr,
 486                                 sizeof(usess->metadata_attr));
 487         }
 488         rcu_read_unlock();
 489
 490         DBG2("Channel %s created successfully", uchan->name);
 491         if (domain != LTTNG_DOMAIN_UST) {
 492                 struct agent *agt = trace_ust_find_agent(usess, domain);
 493
 494                 if (!agt) {
 495                         agt = agent_create(domain);
 496                         if (!agt) {
 497                                 ret = LTTNG_ERR_NOMEM;
 498                                 goto error_free_chan;
 499                         }
 500                         agent_add(agt, usess->agents);
 501                 }
 502         }
 503
 504         channel_attr_destroy(defattr);
 505         return LTTNG_OK;
 506
 507 error_free_chan:
 508         /*
 509          * No need to remove the channel from the hash table because at this point
 510          * it was not added hence the direct call and no call_rcu().
 511          */
 512         trace_ust_destroy_channel(uchan);
 513 error:
 514         channel_attr_destroy(defattr);
 515         return ret;
 516 }
 517
 518 /*
 519  * Disable UST channel for session and domain.
 520  */
 521 int channel_ust_disable(struct ltt_ust_session *usess,
 522                 struct ltt_ust_channel *uchan)
 523 {
 524         int ret = LTTNG_OK;
 525
 526         assert(usess);
 527         assert(uchan);
 528
 529         /* Already disabled */
 530         if (uchan->enabled == 0) {
 531                 DBG2("Channel UST %s already disabled", uchan->name);
 532                 goto end;
 533         }
 534
 535         DBG2("Channel %s being disabled in UST global domain", uchan->name);
 536         /* Disable channel for global domain */
 537         ret = ust_app_disable_channel_glb(usess, uchan);
 538         if (ret < 0 && ret != -LTTNG_UST_ERR_EXIST) {
 539                 ret = LTTNG_ERR_UST_CHAN_DISABLE_FAIL;
 540                 goto error;
 541         }
 542
 543         uchan->enabled = 0;
 544
 545         DBG2("Channel %s disabled successfully", uchan->name);
 546
 547         return LTTNG_OK;
 548
 549 end:
 550 error:
 551         return ret;
 552 }