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 /*
 183  * Create kernel channel of the kernel session and notify kernel thread.
 184  */
 185 int channel_kernel_create(struct ltt_kernel_session *ksession,
 186                 struct lttng_channel *attr, int kernel_pipe)
 187 {
 188         int ret;
 189         struct lttng_channel *defattr = NULL;
 190
 191         assert(ksession);
 192
 193         /* Creating channel attributes if needed */
 194         if (attr == NULL) {
 195                 defattr = channel_new_default_attr(LTTNG_DOMAIN_KERNEL,
 196                                 LTTNG_BUFFER_GLOBAL);
 197                 if (defattr == NULL) {
 198                         ret = LTTNG_ERR_FATAL;
 199                         goto error;
 200                 }
 201                 attr = defattr;
 202         }
 203
 204         if (ksession->snapshot_mode) {
 205                 /* Force channel attribute for snapshot mode. */
 206                 attr->attr.overwrite = 1;
 207                 attr->attr.output = LTTNG_EVENT_MMAP;
 208         }
 209
 210         /* Channel not found, creating it */
 211         ret = kernel_create_channel(ksession, attr);
 212         if (ret < 0) {
 213                 ret = LTTNG_ERR_KERN_CHAN_FAIL;
 214                 goto error;
 215         }
 216
 217         /* Notify kernel thread that there is a new channel */
 218         ret = notify_thread_pipe(kernel_pipe);
 219         if (ret < 0) {
 220                 ret = LTTNG_ERR_FATAL;
 221                 goto error;
 222         }
 223
 224         ret = LTTNG_OK;
 225 error:
 226         free(defattr);
 227         return ret;
 228 }
 229
 230 /*
 231  * Enable UST channel for session and domain.
 232  */
 233 int channel_ust_enable(struct ltt_ust_session *usess,
 234                 struct ltt_ust_channel *uchan)
 235 {
 236         int ret = LTTNG_OK;
 237
 238         assert(usess);
 239         assert(uchan);
 240
 241         /* If already enabled, everything is OK */
 242         if (uchan->enabled) {
 243                 DBG3("Channel %s already enabled. Skipping", uchan->name);
 244                 ret = LTTNG_ERR_UST_CHAN_EXIST;
 245                 goto end;
 246         }
 247
 248         DBG2("Channel %s being enabled in UST domain", uchan->name);
 249
 250         /*
 251          * Enable channel for UST global domain on all applications. Ignore return
 252          * value here since whatever error we got, it means that the channel was
 253          * not created on one or many registered applications and we can not report
 254          * this to the user yet. However, at this stage, the channel was
 255          * successfully created on the session daemon side so the enable-channel
 256          * command is a success.
 257          */
 258         (void) ust_app_enable_channel_glb(usess, uchan);
 259
 260         uchan->enabled = 1;
 261         DBG2("Channel %s enabled successfully", uchan->name);
 262
 263 end:
 264         return ret;
 265 }
 266
 267 /*
 268  * Create UST channel for session and domain.
 269  */
 270 int channel_ust_create(struct ltt_ust_session *usess,
 271                 struct lttng_channel *attr, enum lttng_buffer_type type)
 272 {
 273         int ret = LTTNG_OK;
 274         struct ltt_ust_channel *uchan = NULL;
 275         struct lttng_channel *defattr = NULL;
 276         enum lttng_domain_type domain = LTTNG_DOMAIN_UST;
 277
 278         assert(usess);
 279
 280         /* Creating channel attributes if needed */
 281         if (attr == NULL) {
 282                 defattr = channel_new_default_attr(LTTNG_DOMAIN_UST, type);
 283                 if (defattr == NULL) {
 284                         ret = LTTNG_ERR_FATAL;
 285                         goto error;
 286                 }
 287                 attr = defattr;
 288         } else {
 289                 /*
 290                  * HACK: Set the channel's subdomain (JUL, Log4j, Python, etc.)
 291                  * based on the default name.
 292                  */
 293                 if (!strcmp(attr->name, DEFAULT_JUL_CHANNEL_NAME)) {
 294                         domain = LTTNG_DOMAIN_JUL;
 295                 } else if (!strcmp(attr->name, DEFAULT_LOG4J_CHANNEL_NAME)) {
 296                         domain = LTTNG_DOMAIN_LOG4J;
 297                 } else if (!strcmp(attr->name, DEFAULT_PYTHON_CHANNEL_NAME)) {
 298                         domain = LTTNG_DOMAIN_PYTHON;
 299                 }
 300         }
 301
 302         if (usess->snapshot_mode) {
 303                 /* Force channel attribute for snapshot mode. */
 304                 attr->attr.overwrite = 1;
 305                 attr->attr.output = LTTNG_EVENT_MMAP;
 306         }
 307
 308         /*
 309          * Validate UST buffer size and number of buffers: must both be power of 2
 310          * and nonzero. We validate right here for UST, because applications will
 311          * not report the error to the user (unlike kernel tracing).
 312          */
 313         if (!attr->attr.subbuf_size ||
 314                         (attr->attr.subbuf_size & (attr->attr.subbuf_size - 1))) {
 315                 ret = LTTNG_ERR_INVALID;
 316                 goto error;
 317         }
 318
 319         /*
 320          * Invalid subbuffer size if it's lower then the page size.
 321          */
 322         if (attr->attr.subbuf_size < page_size) {
 323                 ret = LTTNG_ERR_INVALID;
 324                 goto error;
 325         }
 326
 327         if (!attr->attr.num_subbuf ||
 328                         (attr->attr.num_subbuf & (attr->attr.num_subbuf - 1))) {
 329                 ret = LTTNG_ERR_INVALID;
 330                 goto error;
 331         }
 332
 333         if (attr->attr.output != LTTNG_EVENT_MMAP) {
 334                 ret = LTTNG_ERR_NOT_SUPPORTED;
 335                 goto error;
 336         }
 337
 338         /*
 339          * The tracefile_size should not be < to the subbuf_size, otherwise
 340          * we won't be able to write the packets on disk
 341          */
 342         if ((attr->attr.tracefile_size > 0) &&
 343                         (attr->attr.tracefile_size < attr->attr.subbuf_size)) {
 344                 ret = LTTNG_ERR_INVALID;
 345                 goto error;
 346         }
 347
 348         /* Validate buffer type. */
 349         switch (type) {
 350         case LTTNG_BUFFER_PER_PID:
 351                 break;
 352         case LTTNG_BUFFER_PER_UID:
 353                 break;
 354         default:
 355                 ret = LTTNG_ERR_BUFFER_NOT_SUPPORTED;
 356                 goto error;
 357         }
 358
 359         /* Create UST channel */
 360         uchan = trace_ust_create_channel(attr, domain);
 361         if (uchan == NULL) {
 362                 ret = LTTNG_ERR_FATAL;
 363                 goto error;
 364         }
 365
 366         uchan->enabled = 1;
 367         if (trace_ust_is_max_id(usess->used_channel_id)) {
 368                 ret = LTTNG_ERR_UST_CHAN_FAIL;
 369                 goto error;
 370         }
 371         uchan->id = trace_ust_get_next_chan_id(usess);
 372
 373         DBG2("Channel %s is being created for UST with buffer %d and id %" PRIu64,
 374                         uchan->name, type, uchan->id);
 375
 376         /* Flag session buffer type. */
 377         if (!usess->buffer_type_changed) {
 378                 usess->buffer_type = type;
 379                 usess->buffer_type_changed = 1;
 380         } else if (usess->buffer_type != type) {
 381                 /* Buffer type was already set. Refuse to create channel. */
 382                 ret = LTTNG_ERR_BUFFER_TYPE_MISMATCH;
 383                 goto error_free_chan;
 384         }
 385
 386         /* Enable channel for global domain */
 387         ret = ust_app_create_channel_glb(usess, uchan);
 388         if (ret < 0 && ret != -LTTNG_UST_ERR_EXIST) {
 389                 ret = LTTNG_ERR_UST_CHAN_FAIL;
 390                 goto error_free_chan;
 391         }
 392
 393         /* Adding the channel to the channel hash table. */
 394         rcu_read_lock();
 395         if (strncmp(uchan->name, DEFAULT_METADATA_NAME,
 396                                 sizeof(uchan->name))) {
 397                 lttng_ht_add_unique_str(usess->domain_global.channels, &uchan->node);
 398         } else {
 399                 /*
 400                  * Copy channel attribute to session if this is metadata so if NO
 401                  * application exists we can access that data in the shadow copy during
 402                  * the global update of newly registered application.
 403                  */
 404                 memcpy(&usess->metadata_attr, &uchan->attr,
 405                                 sizeof(usess->metadata_attr));
 406         }
 407         rcu_read_unlock();
 408
 409         DBG2("Channel %s created successfully", uchan->name);
 410         if (domain != LTTNG_DOMAIN_UST) {
 411                 struct agent *agt = trace_ust_find_agent(usess, domain);
 412
 413                 if (!agt) {
 414                         agt = agent_create(domain);
 415                         if (!agt) {
 416                                 ret = LTTNG_ERR_NOMEM;
 417                                 goto error_free_chan;
 418                         }
 419                         agent_add(agt, usess->agents);
 420                 }
 421         }
 422
 423         free(defattr);
 424         return LTTNG_OK;
 425
 426 error_free_chan:
 427         /*
 428          * No need to remove the channel from the hash table because at this point
 429          * it was not added hence the direct call and no call_rcu().
 430          */
 431         trace_ust_destroy_channel(uchan);
 432 error:
 433         free(defattr);
 434         return ret;
 435 }
 436
 437 /*
 438  * Disable UST channel for session and domain.
 439  */
 440 int channel_ust_disable(struct ltt_ust_session *usess,
 441                 struct ltt_ust_channel *uchan)
 442 {
 443         int ret = LTTNG_OK;
 444
 445         assert(usess);
 446         assert(uchan);
 447
 448         /* Already disabled */
 449         if (uchan->enabled == 0) {
 450                 DBG2("Channel UST %s already disabled", uchan->name);
 451                 goto end;
 452         }
 453
 454         DBG2("Channel %s being disabled in UST global domain", uchan->name);
 455         /* Disable channel for global domain */
 456         ret = ust_app_disable_channel_glb(usess, uchan);
 457         if (ret < 0 && ret != -LTTNG_UST_ERR_EXIST) {
 458                 ret = LTTNG_ERR_UST_CHAN_DISABLE_FAIL;
 459                 goto error;
 460         }
 461
 462         uchan->enabled = 0;
 463
 464         DBG2("Channel %s disabled successfully", uchan->name);
 465
 466         return LTTNG_OK;
 467
 468 end:
 469 error:
 470         return ret;
 471 }