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