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 /*
 172  * Create kernel channel of the kernel session and notify kernel thread.
 173  */
 174 int channel_kernel_create(struct ltt_kernel_session *ksession,
 175                 struct lttng_channel *attr, int kernel_pipe)
 176 {
 177         int ret;
 178         struct lttng_channel *defattr = NULL;
 179
 180         assert(ksession);
 181
 182         /* Creating channel attributes if needed */
 183         if (attr == NULL) {
 184                 defattr = channel_new_default_attr(LTTNG_DOMAIN_KERNEL,
 185                                 LTTNG_BUFFER_GLOBAL);
 186                 if (defattr == NULL) {
 187                         ret = LTTNG_ERR_FATAL;
 188                         goto error;
 189                 }
 190                 attr = defattr;
 191         }
 192
 193         if (ksession->snapshot_mode) {
 194                 /* Force channel attribute for snapshot mode. */
 195                 attr->attr.overwrite = 1;
 196                 attr->attr.output = LTTNG_EVENT_MMAP;
 197         }
 198
 199         /* Channel not found, creating it */
 200         ret = kernel_create_channel(ksession, attr);
 201         if (ret < 0) {
 202                 ret = LTTNG_ERR_KERN_CHAN_FAIL;
 203                 goto error;
 204         }
 205
 206         /* Notify kernel thread that there is a new channel */
 207         ret = notify_thread_pipe(kernel_pipe);
 208         if (ret < 0) {
 209                 ret = LTTNG_ERR_FATAL;
 210                 goto error;
 211         }
 212
 213         ret = LTTNG_OK;
 214 error:
 215         free(defattr);
 216         return ret;
 217 }
 218
 219 /*
 220  * Enable UST channel for session and domain.
 221  */
 222 int channel_ust_enable(struct ltt_ust_session *usess,
 223                 struct ltt_ust_channel *uchan)
 224 {
 225         int ret = LTTNG_OK;
 226
 227         assert(usess);
 228         assert(uchan);
 229
 230         /* If already enabled, everything is OK */
 231         if (uchan->enabled) {
 232                 DBG3("Channel %s already enabled. Skipping", uchan->name);
 233                 ret = LTTNG_ERR_UST_CHAN_EXIST;
 234                 goto end;
 235         }
 236
 237         DBG2("Channel %s being enabled in UST domain", uchan->name);
 238
 239         /*
 240          * Enable channel for UST global domain on all applications. Ignore return
 241          * value here since whatever error we got, it means that the channel was
 242          * not created on one or many registered applications and we can not report
 243          * this to the user yet. However, at this stage, the channel was
 244          * successfully created on the session daemon side so the enable-channel
 245          * command is a success.
 246          */
 247         (void) ust_app_enable_channel_glb(usess, uchan);
 248
 249         uchan->enabled = 1;
 250         DBG2("Channel %s enabled successfully", uchan->name);
 251
 252 end:
 253         return ret;
 254 }
 255
 256 /*
 257  * Create UST channel for session and domain.
 258  */
 259 int channel_ust_create(struct ltt_ust_session *usess,
 260                 struct lttng_channel *attr, enum lttng_buffer_type type)
 261 {
 262         int ret = LTTNG_OK;
 263         struct ltt_ust_channel *uchan = NULL;
 264         struct lttng_channel *defattr = NULL;
 265
 266         assert(usess);
 267
 268         /* Creating channel attributes if needed */
 269         if (attr == NULL) {
 270                 defattr = channel_new_default_attr(LTTNG_DOMAIN_UST, type);
 271                 if (defattr == NULL) {
 272                         ret = LTTNG_ERR_FATAL;
 273                         goto error;
 274                 }
 275                 attr = defattr;
 276         }
 277
 278         if (usess->snapshot_mode) {
 279                 /* Force channel attribute for snapshot mode. */
 280                 attr->attr.overwrite = 1;
 281                 attr->attr.output = LTTNG_EVENT_MMAP;
 282         }
 283
 284         /*
 285          * Validate UST buffer size and number of buffers: must both be power of 2
 286          * and nonzero. We validate right here for UST, because applications will
 287          * not report the error to the user (unlike kernel tracing).
 288          */
 289         if (!attr->attr.subbuf_size ||
 290                         (attr->attr.subbuf_size & (attr->attr.subbuf_size - 1))) {
 291                 ret = LTTNG_ERR_INVALID;
 292                 goto error;
 293         }
 294
 295         /*
 296          * Invalid subbuffer size if it's lower then the page size.
 297          */
 298         if (attr->attr.subbuf_size < page_size) {
 299                 ret = LTTNG_ERR_INVALID;
 300                 goto error;
 301         }
 302
 303         if (!attr->attr.num_subbuf ||
 304                         (attr->attr.num_subbuf & (attr->attr.num_subbuf - 1))) {
 305                 ret = LTTNG_ERR_INVALID;
 306                 goto error;
 307         }
 308
 309         if (attr->attr.output != LTTNG_EVENT_MMAP) {
 310                 ret = LTTNG_ERR_NOT_SUPPORTED;
 311                 goto error;
 312         }
 313
 314         /*
 315          * The tracefile_size should not be < to the subbuf_size, otherwise
 316          * we won't be able to write the packets on disk
 317          */
 318         if ((attr->attr.tracefile_size > 0) &&
 319                         (attr->attr.tracefile_size < attr->attr.subbuf_size)) {
 320                 ret = LTTNG_ERR_INVALID;
 321                 goto error;
 322         }
 323
 324         /* Validate buffer type. */
 325         switch (type) {
 326         case LTTNG_BUFFER_PER_PID:
 327                 break;
 328         case LTTNG_BUFFER_PER_UID:
 329                 break;
 330         default:
 331                 ret = LTTNG_ERR_BUFFER_NOT_SUPPORTED;
 332                 goto error;
 333         }
 334
 335         /* Create UST channel */
 336         uchan = trace_ust_create_channel(attr);
 337         if (uchan == NULL) {
 338                 ret = LTTNG_ERR_FATAL;
 339                 goto error;
 340         }
 341         uchan->enabled = 1;
 342         if (trace_ust_is_max_id(usess->used_channel_id)) {
 343                 ret = LTTNG_ERR_UST_CHAN_FAIL;
 344                 goto error;
 345         }
 346         uchan->id = trace_ust_get_next_chan_id(usess);
 347
 348         DBG2("Channel %s is being created for UST with buffer %d and id %" PRIu64,
 349                         uchan->name, type, uchan->id);
 350
 351         /* Flag session buffer type. */
 352         if (!usess->buffer_type_changed) {
 353                 usess->buffer_type = type;
 354                 usess->buffer_type_changed = 1;
 355         } else if (usess->buffer_type != type) {
 356                 /* Buffer type was already set. Refuse to create channel. */
 357                 ret = LTTNG_ERR_BUFFER_TYPE_MISMATCH;
 358                 goto error_free_chan;
 359         }
 360
 361         /* Enable channel for global domain */
 362         ret = ust_app_create_channel_glb(usess, uchan);
 363         if (ret < 0 && ret != -LTTNG_UST_ERR_EXIST) {
 364                 ret = LTTNG_ERR_UST_CHAN_FAIL;
 365                 goto error_free_chan;
 366         }
 367
 368         /* Adding the channel to the channel hash table. */
 369         rcu_read_lock();
 370         if (strncmp(uchan->name, DEFAULT_METADATA_NAME,
 371                                 sizeof(uchan->name))) {
 372                 lttng_ht_add_unique_str(usess->domain_global.channels, &uchan->node);
 373         } else {
 374                 /*
 375                  * Copy channel attribute to session if this is metadata so if NO
 376                  * application exists we can access that data in the shadow copy during
 377                  * the global update of newly registered application.
 378                  */
 379                 memcpy(&usess->metadata_attr, &uchan->attr,
 380                                 sizeof(usess->metadata_attr));
 381         }
 382         rcu_read_unlock();
 383
 384         DBG2("Channel %s created successfully", uchan->name);
 385
 386         free(defattr);
 387         return LTTNG_OK;
 388
 389 error_free_chan:
 390         /*
 391          * No need to remove the channel from the hash table because at this point
 392          * it was not added hence the direct call and no call_rcu().
 393          */
 394         trace_ust_destroy_channel(uchan);
 395 error:
 396         free(defattr);
 397         return ret;
 398 }
 399
 400 /*
 401  * Disable UST channel for session and domain.
 402  */
 403 int channel_ust_disable(struct ltt_ust_session *usess,
 404                 struct ltt_ust_channel *uchan)
 405 {
 406         int ret = LTTNG_OK;
 407
 408         assert(usess);
 409         assert(uchan);
 410
 411         /* Already disabled */
 412         if (uchan->enabled == 0) {
 413                 DBG2("Channel UST %s already disabled", uchan->name);
 414                 goto end;
 415         }
 416
 417         DBG2("Channel %s being disabled in UST global domain", uchan->name);
 418         /* Disable channel for global domain */
 419         ret = ust_app_disable_channel_glb(usess, uchan);
 420         if (ret < 0 && ret != -LTTNG_UST_ERR_EXIST) {
 421                 ret = LTTNG_ERR_UST_CHAN_DISABLE_FAIL;
 422                 goto error;
 423         }
 424
 425         uchan->enabled = 0;
 426
 427         DBG2("Channel %s disabled successfully", uchan->name);
 428
 429         return LTTNG_OK;
 430
 431 end:
 432 error:
 433         return ret;
 434 }