src/bin/lttng-sessiond/channel.c

   1 /*
   2  * Copyright (C) 2011 - David Goulet <david.goulet@polymtl.ca>
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License, version 2 only,
   6  * as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11  * GNU General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public License along
  14  * with this program; if not, write to the Free Software Foundation, Inc.,
  15  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  16  */
  17
  18 #define _GNU_SOURCE
  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
  35 /*
  36  * Return allocated channel attributes.
  37  */
  38 struct lttng_channel *channel_new_default_attr(int dom,
  39                 enum lttng_buffer_type type)
  40 {
  41         struct lttng_channel *chan;
  42
  43         chan = zmalloc(sizeof(struct lttng_channel));
  44         if (chan == NULL) {
  45                 PERROR("zmalloc channel init");
  46                 goto error_alloc;
  47         }
  48
  49         if (snprintf(chan->name, sizeof(chan->name), "%s",
  50                                 DEFAULT_CHANNEL_NAME) < 0) {
  51                 PERROR("snprintf default channel name");
  52                 goto error;
  53         }
  54
  55         /* Same for all domains. */
  56         chan->attr.overwrite = DEFAULT_CHANNEL_OVERWRITE;
  57         chan->attr.tracefile_size = DEFAULT_CHANNEL_TRACEFILE_SIZE;
  58         chan->attr.tracefile_count = DEFAULT_CHANNEL_TRACEFILE_COUNT;
  59
  60         switch (dom) {
  61         case LTTNG_DOMAIN_KERNEL:
  62                 assert(type == LTTNG_BUFFER_GLOBAL);
  63                 chan->attr.subbuf_size =
  64                         default_get_kernel_channel_subbuf_size();
  65                 chan->attr.num_subbuf = DEFAULT_KERNEL_CHANNEL_SUBBUF_NUM;
  66                 chan->attr.output = DEFAULT_KERNEL_CHANNEL_OUTPUT;
  67                 chan->attr.switch_timer_interval = DEFAULT_KERNEL_CHANNEL_SWITCH_TIMER;
  68                 chan->attr.read_timer_interval = DEFAULT_KERNEL_CHANNEL_READ_TIMER;
  69                 chan->attr.live_timer_interval = DEFAULT_KERNEL_CHANNEL_LIVE_TIMER;
  70                 break;
  71         case LTTNG_DOMAIN_UST:
  72                 switch (type) {
  73                 case LTTNG_BUFFER_PER_UID:
  74                         chan->attr.subbuf_size = default_get_ust_uid_channel_subbuf_size();
  75                         chan->attr.num_subbuf = DEFAULT_UST_UID_CHANNEL_SUBBUF_NUM;
  76                         chan->attr.output = DEFAULT_UST_UID_CHANNEL_OUTPUT;
  77                         chan->attr.switch_timer_interval =
  78                                 DEFAULT_UST_UID_CHANNEL_SWITCH_TIMER;
  79                         chan->attr.read_timer_interval =
  80                                 DEFAULT_UST_UID_CHANNEL_READ_TIMER;
  81                         chan->attr.live_timer_interval =
  82                                 DEFAULT_UST_UID_CHANNEL_LIVE_TIMER;
  83                         break;
  84                 case LTTNG_BUFFER_PER_PID:
  85                 default:
  86                         chan->attr.subbuf_size = default_get_ust_pid_channel_subbuf_size();
  87                         chan->attr.num_subbuf = DEFAULT_UST_PID_CHANNEL_SUBBUF_NUM;
  88                         chan->attr.output = DEFAULT_UST_PID_CHANNEL_OUTPUT;
  89                         chan->attr.switch_timer_interval =
  90                                 DEFAULT_UST_PID_CHANNEL_SWITCH_TIMER;
  91                         chan->attr.read_timer_interval =
  92                                 DEFAULT_UST_PID_CHANNEL_READ_TIMER;
  93                         chan->attr.live_timer_interval =
  94                                 DEFAULT_UST_UID_CHANNEL_LIVE_TIMER;
  95                         break;
  96                 }
  97                 break;
  98         default:
  99                 goto error;     /* Not implemented */
 100         }
 101
 102         return chan;
 103
 104 error:
 105         free(chan);
 106 error_alloc:
 107         return NULL;
 108 }
 109
 110 /*
 111  * Disable kernel channel of the kernel session.
 112  */
 113 int channel_kernel_disable(struct ltt_kernel_session *ksession,
 114                 char *channel_name)
 115 {
 116         int ret;
 117         struct ltt_kernel_channel *kchan;
 118
 119         assert(ksession);
 120         assert(channel_name);
 121
 122         kchan = trace_kernel_get_channel_by_name(channel_name, ksession);
 123         if (kchan == NULL) {
 124                 ret = LTTNG_ERR_KERN_CHAN_NOT_FOUND;
 125                 goto error;
 126         }
 127
 128         /* Only if channel is enabled disable it. */
 129         if (kchan->enabled == 1) {
 130                 ret = kernel_disable_channel(kchan);
 131                 if (ret < 0 && ret != -EEXIST) {
 132                         ret = LTTNG_ERR_KERN_CHAN_DISABLE_FAIL;
 133                         goto error;
 134                 }
 135         }
 136
 137         ret = LTTNG_OK;
 138
 139 error:
 140         return ret;
 141 }
 142
 143 /*
 144  * Enable kernel channel of the kernel session.
 145  */
 146 int channel_kernel_enable(struct ltt_kernel_session *ksession,
 147                 struct ltt_kernel_channel *kchan)
 148 {
 149         int ret;
 150
 151         assert(ksession);
 152         assert(kchan);
 153
 154         if (kchan->enabled == 0) {
 155                 ret = kernel_enable_channel(kchan);
 156                 if (ret < 0) {
 157                         ret = LTTNG_ERR_KERN_CHAN_ENABLE_FAIL;
 158                         goto error;
 159                 }
 160         } else {
 161                 ret = LTTNG_ERR_KERN_CHAN_EXIST;
 162                 goto error;
 163         }
 164
 165         ret = LTTNG_OK;
 166
 167 error:
 168         return ret;
 169 }
 170
 171 static int channel_validate(struct lttng_channel *attr)
 172 {
 173         /*
 174          * The ringbuffer (both in user space and kernel) behaves badly
 175          * in overwrite mode and with less than 2 subbuffers so block it
 176          * right away and send back an invalid attribute error.
 177          */
 178         if (attr->attr.overwrite && attr->attr.num_subbuf < 2) {
 179                 return -1;
 180         }
 181         return 0;
 182 }
 183
 184 /*
 185  * Create kernel channel of the kernel session and notify kernel thread.
 186  */
 187 int channel_kernel_create(struct ltt_kernel_session *ksession,
 188                 struct lttng_channel *attr, int kernel_pipe)
 189 {
 190         int ret;
 191         struct lttng_channel *defattr = NULL;
 192
 193         assert(ksession);
 194
 195         /* Creating channel attributes if needed */
 196         if (attr == NULL) {
 197                 defattr = channel_new_default_attr(LTTNG_DOMAIN_KERNEL,
 198                                 LTTNG_BUFFER_GLOBAL);
 199                 if (defattr == NULL) {
 200                         ret = LTTNG_ERR_FATAL;
 201                         goto error;
 202                 }
 203                 attr = defattr;
 204         }
 205
 206         if (ksession->snapshot_mode) {
 207                 /* Force channel attribute for snapshot mode. */
 208                 attr->attr.overwrite = 1;
 209                 attr->attr.output = LTTNG_EVENT_MMAP;
 210         }
 211
 212         /* Validate common channel properties. */
 213         if (channel_validate(attr) < 0) {
 214                 ret = LTTNG_ERR_INVALID;
 215                 goto error;
 216         }
 217
 218         /* Channel not found, creating it */
 219         ret = kernel_create_channel(ksession, attr);
 220         if (ret < 0) {
 221                 ret = LTTNG_ERR_KERN_CHAN_FAIL;
 222                 goto error;
 223         }
 224
 225         /* Notify kernel thread that there is a new channel */
 226         ret = notify_thread_pipe(kernel_pipe);
 227         if (ret < 0) {
 228                 ret = LTTNG_ERR_FATAL;
 229                 goto error;
 230         }
 231
 232         ret = LTTNG_OK;
 233 error:
 234         free(defattr);
 235         return ret;
 236 }
 237
 238 /*
 239  * Enable UST channel for session and domain.
 240  */
 241 int channel_ust_enable(struct ltt_ust_session *usess,
 242                 struct ltt_ust_channel *uchan)
 243 {
 244         int ret = LTTNG_OK;
 245
 246         assert(usess);
 247         assert(uchan);
 248
 249         /* If already enabled, everything is OK */
 250         if (uchan->enabled) {
 251                 DBG3("Channel %s already enabled. Skipping", uchan->name);
 252                 ret = LTTNG_ERR_UST_CHAN_EXIST;
 253                 goto end;
 254         }
 255
 256         DBG2("Channel %s being enabled in UST domain", uchan->name);
 257
 258         /*
 259          * Enable channel for UST global domain on all applications. Ignore return
 260          * value here since whatever error we got, it means that the channel was
 261          * not created on one or many registered applications and we can not report
 262          * this to the user yet. However, at this stage, the channel was
 263          * successfully created on the session daemon side so the enable-channel
 264          * command is a success.
 265          */
 266         (void) ust_app_enable_channel_glb(usess, uchan);
 267
 268         uchan->enabled = 1;
 269         DBG2("Channel %s enabled successfully", uchan->name);
 270
 271 end:
 272         return ret;
 273 }
 274
 275 /*
 276  * Create UST channel for session and domain.
 277  */
 278 int channel_ust_create(struct ltt_ust_session *usess,
 279                 struct lttng_channel *attr, enum lttng_buffer_type type)
 280 {
 281         int ret = LTTNG_OK;
 282         struct ltt_ust_channel *uchan = NULL;
 283         struct lttng_channel *defattr = NULL;
 284
 285         assert(usess);
 286
 287         /* Creating channel attributes if needed */
 288         if (attr == NULL) {
 289                 defattr = channel_new_default_attr(LTTNG_DOMAIN_UST, type);
 290                 if (defattr == NULL) {
 291                         ret = LTTNG_ERR_FATAL;
 292                         goto error;
 293                 }
 294                 attr = defattr;
 295         }
 296
 297         if (usess->snapshot_mode) {
 298                 /* Force channel attribute for snapshot mode. */
 299                 attr->attr.overwrite = 1;
 300                 attr->attr.output = LTTNG_EVENT_MMAP;
 301         }
 302
 303         /* Validate common channel properties. */
 304         if (channel_validate(attr) < 0) {
 305                 ret = LTTNG_ERR_INVALID;
 306                 goto error;
 307         }
 308
 309         /*
 310          * Validate UST buffer size and number of buffers: must both be power of 2
 311          * and nonzero. We validate right here for UST, because applications will
 312          * not report the error to the user (unlike kernel tracing).
 313          */
 314         if (!attr->attr.subbuf_size ||
 315                         (attr->attr.subbuf_size & (attr->attr.subbuf_size - 1))) {
 316                 ret = LTTNG_ERR_INVALID;
 317                 goto error;
 318         }
 319
 320         /*
 321          * Invalid subbuffer size if it's lower then the page size.
 322          */
 323         if (attr->attr.subbuf_size < page_size) {
 324                 ret = LTTNG_ERR_INVALID;
 325                 goto error;
 326         }
 327
 328         if (!attr->attr.num_subbuf ||
 329                         (attr->attr.num_subbuf & (attr->attr.num_subbuf - 1))) {
 330                 ret = LTTNG_ERR_INVALID;
 331                 goto error;
 332         }
 333
 334         if (attr->attr.output != LTTNG_EVENT_MMAP) {
 335                 ret = LTTNG_ERR_NOT_SUPPORTED;
 336                 goto error;
 337         }
 338
 339         /*
 340          * The tracefile_size should not be < to the subbuf_size, otherwise
 341          * we won't be able to write the packets on disk
 342          */
 343         if ((attr->attr.tracefile_size > 0) &&
 344                         (attr->attr.tracefile_size < attr->attr.subbuf_size)) {
 345                 ret = LTTNG_ERR_INVALID;
 346                 goto error;
 347         }
 348
 349         /* Validate buffer type. */
 350         switch (type) {
 351         case LTTNG_BUFFER_PER_PID:
 352                 break;
 353         case LTTNG_BUFFER_PER_UID:
 354                 break;
 355         default:
 356                 ret = LTTNG_ERR_BUFFER_NOT_SUPPORTED;
 357                 goto error;
 358         }
 359
 360         /* Create UST channel */
 361         uchan = trace_ust_create_channel(attr, LTTNG_DOMAIN_UST);
 362         if (uchan == NULL) {
 363                 ret = LTTNG_ERR_FATAL;
 364                 goto error;
 365         }
 366
 367         /*
 368          * HACK: Set the channel's subdomain (JUL, Log4j, Python, etc.)
 369          * based on the default name.
 370          */
 371         if (!strcmp(uchan->name, DEFAULT_JUL_CHANNEL_NAME)) {
 372                 uchan->domain = LTTNG_DOMAIN_JUL;
 373         } else if (!strcmp(uchan->name, DEFAULT_LOG4J_CHANNEL_NAME)) {
 374                 uchan->domain = LTTNG_DOMAIN_LOG4J;
 375         } else if (!strcmp(uchan->name, DEFAULT_PYTHON_CHANNEL_NAME)) {
 376                 uchan->domain = LTTNG_DOMAIN_PYTHON;
 377         }
 378
 379         uchan->enabled = 1;
 380         if (trace_ust_is_max_id(usess->used_channel_id)) {
 381                 ret = LTTNG_ERR_UST_CHAN_FAIL;
 382                 goto error;
 383         }
 384         uchan->id = trace_ust_get_next_chan_id(usess);
 385
 386         DBG2("Channel %s is being created for UST with buffer %d and id %" PRIu64,
 387                         uchan->name, type, uchan->id);
 388
 389         /* Flag session buffer type. */
 390         if (!usess->buffer_type_changed) {
 391                 usess->buffer_type = type;
 392                 usess->buffer_type_changed = 1;
 393         } else if (usess->buffer_type != type) {
 394                 /* Buffer type was already set. Refuse to create channel. */
 395                 ret = LTTNG_ERR_BUFFER_TYPE_MISMATCH;
 396                 goto error_free_chan;
 397         }
 398
 399         /* Enable channel for global domain */
 400         ret = ust_app_create_channel_glb(usess, uchan);
 401         if (ret < 0 && ret != -LTTNG_UST_ERR_EXIST) {
 402                 ret = LTTNG_ERR_UST_CHAN_FAIL;
 403                 goto error_free_chan;
 404         }
 405
 406         /* Adding the channel to the channel hash table. */
 407         rcu_read_lock();
 408         if (strncmp(uchan->name, DEFAULT_METADATA_NAME,
 409                                 sizeof(uchan->name))) {
 410                 lttng_ht_add_unique_str(usess->domain_global.channels, &uchan->node);
 411         } else {
 412                 /*
 413                  * Copy channel attribute to session if this is metadata so if NO
 414                  * application exists we can access that data in the shadow copy during
 415                  * the global update of newly registered application.
 416                  */
 417                 memcpy(&usess->metadata_attr, &uchan->attr,
 418                                 sizeof(usess->metadata_attr));
 419         }
 420         rcu_read_unlock();
 421
 422         DBG2("Channel %s created successfully", uchan->name);
 423
 424         free(defattr);
 425         return LTTNG_OK;
 426
 427 error_free_chan:
 428         /*
 429          * No need to remove the channel from the hash table because at this point
 430          * it was not added hence the direct call and no call_rcu().
 431          */
 432         trace_ust_destroy_channel(uchan);
 433 error:
 434         free(defattr);
 435         return ret;
 436 }
 437
 438 /*
 439  * Disable UST channel for session and domain.
 440  */
 441 int channel_ust_disable(struct ltt_ust_session *usess,
 442                 struct ltt_ust_channel *uchan)
 443 {
 444         int ret = LTTNG_OK;
 445
 446         assert(usess);
 447         assert(uchan);
 448
 449         /* Already disabled */
 450         if (uchan->enabled == 0) {
 451                 DBG2("Channel UST %s already disabled", uchan->name);
 452                 goto end;
 453         }
 454
 455         DBG2("Channel %s being disabled in UST global domain", uchan->name);
 456         /* Disable channel for global domain */
 457         ret = ust_app_disable_channel_glb(usess, uchan);
 458         if (ret < 0 && ret != -LTTNG_UST_ERR_EXIST) {
 459                 ret = LTTNG_ERR_UST_CHAN_DISABLE_FAIL;
 460                 goto error;
 461         }
 462
 463         uchan->enabled = 0;
 464
 465         DBG2("Channel %s disabled successfully", uchan->name);
 466
 467         return LTTNG_OK;
 468
 469 end:
 470 error:
 471         return ret;
 472 }