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