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 #include <inttypes.h>
  20 #include <string.h>
  21 #include <unistd.h>
  22
  23 #include <common/common.h>
  24 #include <common/defaults.h>
  25 #include <common/sessiond-comm/sessiond-comm.h>
  26
  27 #include "channel.h"
  28 #include "lttng-sessiond.h"
  29 #include "kernel.h"
  30 #include "ust-ctl.h"
  31 #include "utils.h"
  32 #include "ust-app.h"
  33
  34 /*
  35  * Return allocated channel attributes.
  36  */
  37 struct lttng_channel *channel_new_default_attr(int dom,
  38                 enum lttng_buffer_type type)
  39 {
  40         struct lttng_channel *chan;
  41
  42         chan = zmalloc(sizeof(struct lttng_channel));
  43         if (chan == NULL) {
  44                 PERROR("zmalloc channel init");
  45                 goto error_alloc;
  46         }
  47
  48         if (snprintf(chan->name, sizeof(chan->name), "%s",
  49                                 DEFAULT_CHANNEL_NAME) < 0) {
  50                 PERROR("snprintf default channel name");
  51                 goto error;
  52         }
  53
  54         /* Same for all domains. */
  55         chan->attr.overwrite = DEFAULT_CHANNEL_OVERWRITE;
  56         chan->attr.tracefile_size = DEFAULT_CHANNEL_TRACEFILE_SIZE;
  57         chan->attr.tracefile_count = DEFAULT_CHANNEL_TRACEFILE_COUNT;
  58
  59         switch (dom) {
  60         case LTTNG_DOMAIN_KERNEL:
  61                 assert(type == LTTNG_BUFFER_GLOBAL);
  62                 chan->attr.subbuf_size =
  63                         default_get_kernel_channel_subbuf_size();
  64                 chan->attr.num_subbuf = DEFAULT_KERNEL_CHANNEL_SUBBUF_NUM;
  65                 chan->attr.output = DEFAULT_KERNEL_CHANNEL_OUTPUT;
  66                 chan->attr.switch_timer_interval = DEFAULT_KERNEL_CHANNEL_SWITCH_TIMER;
  67                 chan->attr.read_timer_interval = DEFAULT_KERNEL_CHANNEL_READ_TIMER;
  68                 chan->attr.live_timer_interval = DEFAULT_KERNEL_CHANNEL_LIVE_TIMER;
  69                 break;
  70         case LTTNG_DOMAIN_UST:
  71                 switch (type) {
  72                 case LTTNG_BUFFER_PER_UID:
  73                         chan->attr.subbuf_size = default_get_ust_uid_channel_subbuf_size();
  74                         chan->attr.num_subbuf = DEFAULT_UST_UID_CHANNEL_SUBBUF_NUM;
  75                         chan->attr.output = DEFAULT_UST_UID_CHANNEL_OUTPUT;
  76                         chan->attr.switch_timer_interval =
  77                                 DEFAULT_UST_UID_CHANNEL_SWITCH_TIMER;
  78                         chan->attr.read_timer_interval =
  79                                 DEFAULT_UST_UID_CHANNEL_READ_TIMER;
  80                         chan->attr.live_timer_interval =
  81                                 DEFAULT_UST_UID_CHANNEL_LIVE_TIMER;
  82                         break;
  83                 case LTTNG_BUFFER_PER_PID:
  84                 default:
  85                         chan->attr.subbuf_size = default_get_ust_pid_channel_subbuf_size();
  86                         chan->attr.num_subbuf = DEFAULT_UST_PID_CHANNEL_SUBBUF_NUM;
  87                         chan->attr.output = DEFAULT_UST_PID_CHANNEL_OUTPUT;
  88                         chan->attr.switch_timer_interval =
  89                                 DEFAULT_UST_PID_CHANNEL_SWITCH_TIMER;
  90                         chan->attr.read_timer_interval =
  91                                 DEFAULT_UST_PID_CHANNEL_READ_TIMER;
  92                         chan->attr.live_timer_interval =
  93                                 DEFAULT_UST_UID_CHANNEL_LIVE_TIMER;
  94                         break;
  95                 }
  96                 break;
  97         default:
  98                 goto error;     /* Not implemented */
  99         }
 100
 101         return chan;
 102
 103 error:
 104         free(chan);
 105 error_alloc:
 106         return NULL;
 107 }
 108
 109 /*
 110  * Disable kernel channel of the kernel session.
 111  */
 112 int channel_kernel_disable(struct ltt_kernel_session *ksession,
 113                 char *channel_name)
 114 {
 115         int ret;
 116         struct ltt_kernel_channel *kchan;
 117
 118         assert(ksession);
 119         assert(channel_name);
 120
 121         kchan = trace_kernel_get_channel_by_name(channel_name, ksession);
 122         if (kchan == NULL) {
 123                 ret = LTTNG_ERR_KERN_CHAN_NOT_FOUND;
 124                 goto error;
 125         }
 126
 127         /* Only if channel is enabled disable it. */
 128         if (kchan->enabled == 1) {
 129                 ret = kernel_disable_channel(kchan);
 130                 if (ret < 0 && ret != -EEXIST) {
 131                         ret = LTTNG_ERR_KERN_CHAN_DISABLE_FAIL;
 132                         goto error;
 133                 }
 134         }
 135
 136         ret = LTTNG_OK;
 137
 138 error:
 139         return ret;
 140 }
 141
 142 /*
 143  * Enable kernel channel of the kernel session.
 144  */
 145 int channel_kernel_enable(struct ltt_kernel_session *ksession,
 146                 struct ltt_kernel_channel *kchan)
 147 {
 148         int ret;
 149
 150         assert(ksession);
 151         assert(kchan);
 152
 153         if (kchan->enabled == 0) {
 154                 ret = kernel_enable_channel(kchan);
 155                 if (ret < 0) {
 156                         ret = LTTNG_ERR_KERN_CHAN_ENABLE_FAIL;
 157                         goto error;
 158                 }
 159         } else {
 160                 ret = LTTNG_ERR_KERN_CHAN_EXIST;
 161                 goto error;
 162         }
 163
 164         ret = LTTNG_OK;
 165
 166 error:
 167         return ret;
 168 }
 169
 170 /*
 171  * Create kernel channel of the kernel session and notify kernel thread.
 172  */
 173 int channel_kernel_create(struct ltt_kernel_session *ksession,
 174                 struct lttng_channel *attr, int kernel_pipe)
 175 {
 176         int ret;
 177         struct lttng_channel *defattr = NULL;
 178
 179         assert(ksession);
 180
 181         /* Creating channel attributes if needed */
 182         if (attr == NULL) {
 183                 defattr = channel_new_default_attr(LTTNG_DOMAIN_KERNEL,
 184                                 LTTNG_BUFFER_GLOBAL);
 185                 if (defattr == NULL) {
 186                         ret = LTTNG_ERR_FATAL;
 187                         goto error;
 188                 }
 189                 attr = defattr;
 190         }
 191
 192         if (ksession->snapshot_mode) {
 193                 /* Force channel attribute for snapshot mode. */
 194                 attr->attr.overwrite = 1;
 195                 attr->attr.output = LTTNG_EVENT_MMAP;
 196         }
 197
 198         /* Channel not found, creating it */
 199         ret = kernel_create_channel(ksession, attr);
 200         if (ret < 0) {
 201                 ret = LTTNG_ERR_KERN_CHAN_FAIL;
 202                 goto error;
 203         }
 204
 205         /* Notify kernel thread that there is a new channel */
 206         ret = notify_thread_pipe(kernel_pipe);
 207         if (ret < 0) {
 208                 ret = LTTNG_ERR_FATAL;
 209                 goto error;
 210         }
 211
 212         ret = LTTNG_OK;
 213 error:
 214         free(defattr);
 215         return ret;
 216 }
 217
 218 /*
 219  * Enable UST channel for session and domain.
 220  */
 221 int channel_ust_enable(struct ltt_ust_session *usess,
 222                 struct ltt_ust_channel *uchan)
 223 {
 224         int ret = LTTNG_OK;
 225
 226         assert(usess);
 227         assert(uchan);
 228
 229         /* If already enabled, everything is OK */
 230         if (uchan->enabled) {
 231                 DBG3("Channel %s already enabled. Skipping", uchan->name);
 232                 ret = LTTNG_ERR_UST_CHAN_EXIST;
 233                 goto end;
 234         }
 235
 236         DBG2("Channel %s being enabled in UST domain", uchan->name);
 237
 238         /*
 239          * Enable channel for UST global domain on all applications. Ignore return
 240          * value here since whatever error we got, it means that the channel was
 241          * not created on one or many registered applications and we can not report
 242          * this to the user yet. However, at this stage, the channel was
 243          * successfully created on the session daemon side so the enable-channel
 244          * command is a success.
 245          */
 246         (void) ust_app_enable_channel_glb(usess, uchan);
 247
 248         uchan->enabled = 1;
 249         DBG2("Channel %s enabled successfully", uchan->name);
 250
 251 end:
 252         return ret;
 253 }
 254
 255 /*
 256  * Create UST channel for session and domain.
 257  */
 258 int channel_ust_create(struct ltt_ust_session *usess,
 259                 struct lttng_channel *attr, enum lttng_buffer_type type)
 260 {
 261         int ret = LTTNG_OK;
 262         struct ltt_ust_channel *uchan = NULL;
 263         struct lttng_channel *defattr = NULL;
 264
 265         assert(usess);
 266
 267         /* Creating channel attributes if needed */
 268         if (attr == NULL) {
 269                 defattr = channel_new_default_attr(LTTNG_DOMAIN_UST, type);
 270                 if (defattr == NULL) {
 271                         ret = LTTNG_ERR_FATAL;
 272                         goto error;
 273                 }
 274                 attr = defattr;
 275         }
 276
 277         if (usess->snapshot_mode) {
 278                 /* Force channel attribute for snapshot mode. */
 279                 attr->attr.overwrite = 1;
 280                 attr->attr.output = LTTNG_EVENT_MMAP;
 281         }
 282
 283         /*
 284          * Validate UST buffer size and number of buffers: must both be power of 2
 285          * and nonzero. We validate right here for UST, because applications will
 286          * not report the error to the user (unlike kernel tracing).
 287          */
 288         if (!attr->attr.subbuf_size ||
 289                         (attr->attr.subbuf_size & (attr->attr.subbuf_size - 1))) {
 290                 ret = LTTNG_ERR_INVALID;
 291                 goto error;
 292         }
 293
 294         /*
 295          * Invalid subbuffer size if it's lower then the page size.
 296          */
 297         if (attr->attr.subbuf_size < page_size) {
 298                 ret = LTTNG_ERR_INVALID;
 299                 goto error;
 300         }
 301
 302         if (!attr->attr.num_subbuf ||
 303                         (attr->attr.num_subbuf & (attr->attr.num_subbuf - 1))) {
 304                 ret = LTTNG_ERR_INVALID;
 305                 goto error;
 306         }
 307
 308         if (attr->attr.output != LTTNG_EVENT_MMAP) {
 309                 ret = LTTNG_ERR_NOT_SUPPORTED;
 310                 goto error;
 311         }
 312
 313         /*
 314          * The tracefile_size should not be < to the subbuf_size, otherwise
 315          * we won't be able to write the packets on disk
 316          */
 317         if ((attr->attr.tracefile_size > 0) &&
 318                         (attr->attr.tracefile_size < attr->attr.subbuf_size)) {
 319                 ret = LTTNG_ERR_INVALID;
 320                 goto error;
 321         }
 322
 323         /* Validate buffer type. */
 324         switch (type) {
 325         case LTTNG_BUFFER_PER_PID:
 326                 break;
 327         case LTTNG_BUFFER_PER_UID:
 328                 break;
 329         default:
 330                 ret = LTTNG_ERR_BUFFER_NOT_SUPPORTED;
 331                 goto error;
 332         }
 333
 334         /* Create UST channel */
 335         uchan = trace_ust_create_channel(attr);
 336         if (uchan == NULL) {
 337                 ret = LTTNG_ERR_FATAL;
 338                 goto error;
 339         }
 340         uchan->enabled = 1;
 341         if (trace_ust_is_max_id(usess->used_channel_id)) {
 342                 ret = LTTNG_ERR_UST_CHAN_FAIL;
 343                 goto error;
 344         }
 345         uchan->id = trace_ust_get_next_chan_id(usess);
 346
 347         DBG2("Channel %s is being created for UST with buffer %d and id %" PRIu64,
 348                         uchan->name, type, uchan->id);
 349
 350         /* Flag session buffer type. */
 351         if (!usess->buffer_type_changed) {
 352                 usess->buffer_type = type;
 353                 usess->buffer_type_changed = 1;
 354         } else if (usess->buffer_type != type) {
 355                 /* Buffer type was already set. Refuse to create channel. */
 356                 ret = LTTNG_ERR_BUFFER_TYPE_MISMATCH;
 357                 goto error_free_chan;
 358         }
 359
 360         /* Enable channel for global domain */
 361         ret = ust_app_create_channel_glb(usess, uchan);
 362         if (ret < 0 && ret != -LTTNG_UST_ERR_EXIST) {
 363                 ret = LTTNG_ERR_UST_CHAN_FAIL;
 364                 goto error_free_chan;
 365         }
 366
 367         /* Adding the channel to the channel hash table. */
 368         rcu_read_lock();
 369         if (strncmp(uchan->name, DEFAULT_METADATA_NAME,
 370                                 sizeof(uchan->name))) {
 371                 lttng_ht_add_unique_str(usess->domain_global.channels, &uchan->node);
 372         } else {
 373                 /*
 374                  * Copy channel attribute to session if this is metadata so if NO
 375                  * application exists we can access that data in the shadow copy during
 376                  * the global update of newly registered application.
 377                  */
 378                 memcpy(&usess->metadata_attr, &uchan->attr,
 379                                 sizeof(usess->metadata_attr));
 380         }
 381         rcu_read_unlock();
 382
 383         DBG2("Channel %s created successfully", uchan->name);
 384
 385         free(defattr);
 386         return LTTNG_OK;
 387
 388 error_free_chan:
 389         /*
 390          * No need to remove the channel from the hash table because at this point
 391          * it was not added hence the direct call and no call_rcu().
 392          */
 393         trace_ust_destroy_channel(uchan);
 394 error:
 395         free(defattr);
 396         return ret;
 397 }
 398
 399 /*
 400  * Disable UST channel for session and domain.
 401  */
 402 int channel_ust_disable(struct ltt_ust_session *usess,
 403                 struct ltt_ust_channel *uchan)
 404 {
 405         int ret = LTTNG_OK;
 406
 407         assert(usess);
 408         assert(uchan);
 409
 410         /* Already disabled */
 411         if (uchan->enabled == 0) {
 412                 DBG2("Channel UST %s already disabled", uchan->name);
 413                 goto end;
 414         }
 415
 416         DBG2("Channel %s being disabled in UST global domain", uchan->name);
 417         /* Disable channel for global domain */
 418         ret = ust_app_disable_channel_glb(usess, uchan);
 419         if (ret < 0 && ret != -LTTNG_UST_ERR_EXIST) {
 420                 ret = LTTNG_ERR_UST_CHAN_DISABLE_FAIL;
 421                 goto error;
 422         }
 423
 424         uchan->enabled = 0;
 425
 426         DBG2("Channel %s disabled successfully", uchan->name);
 427
 428         return LTTNG_OK;
 429
 430 end:
 431 error:
 432         return ret;
 433 }