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