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