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