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 "kernel.h"
  29 #include "ust-ctl.h"
  30 #include "utils.h"
  31 #include "ust-app.h"
  32
  33 /*
  34  * Return allocated channel attributes.
  35  */
  36 struct lttng_channel *channel_new_default_attr(int dom)
  37 {
  38         struct lttng_channel *chan;
  39
  40         chan = zmalloc(sizeof(struct lttng_channel));
  41         if (chan == NULL) {
  42                 PERROR("zmalloc channel init");
  43                 goto error_alloc;
  44         }
  45
  46         if (snprintf(chan->name, sizeof(chan->name), "%s",
  47                                 DEFAULT_CHANNEL_NAME) < 0) {
  48                 PERROR("snprintf default channel name");
  49                 goto error;
  50         }
  51
  52         chan->attr.overwrite = DEFAULT_CHANNEL_OVERWRITE;
  53
  54         switch (dom) {
  55         case LTTNG_DOMAIN_KERNEL:
  56                 chan->attr.subbuf_size =
  57                         default_get_kernel_channel_subbuf_size();
  58                 chan->attr.num_subbuf = DEFAULT_KERNEL_CHANNEL_SUBBUF_NUM;
  59                 chan->attr.output = DEFAULT_KERNEL_CHANNEL_OUTPUT;
  60                 chan->attr.switch_timer_interval = DEFAULT_KERNEL_CHANNEL_SWITCH_TIMER;
  61                 chan->attr.read_timer_interval = DEFAULT_KERNEL_CHANNEL_READ_TIMER;
  62                 break;
  63         case LTTNG_DOMAIN_UST:
  64 #if 0
  65         case LTTNG_DOMAIN_UST_PID:
  66         case LTTNG_DOMAIN_UST_PID_FOLLOW_CHILDREN:
  67         case LTTNG_DOMAIN_UST_EXEC_NAME:
  68 #endif
  69                 chan->attr.subbuf_size = default_get_ust_channel_subbuf_size();
  70                 chan->attr.num_subbuf = DEFAULT_UST_CHANNEL_SUBBUF_NUM;
  71                 chan->attr.output = DEFAULT_UST_CHANNEL_OUTPUT;
  72                 chan->attr.switch_timer_interval = DEFAULT_UST_CHANNEL_SWITCH_TIMER;
  73                 chan->attr.read_timer_interval = DEFAULT_UST_CHANNEL_READ_TIMER;
  74                 break;
  75         default:
  76                 goto error;     /* Not implemented */
  77         }
  78
  79         return chan;
  80
  81 error:
  82         free(chan);
  83 error_alloc:
  84         return NULL;
  85 }
  86
  87 /*
  88  * Disable kernel channel of the kernel session.
  89  */
  90 int channel_kernel_disable(struct ltt_kernel_session *ksession,
  91                 char *channel_name)
  92 {
  93         int ret;
  94         struct ltt_kernel_channel *kchan;
  95
  96         assert(ksession);
  97         assert(channel_name);
  98
  99         kchan = trace_kernel_get_channel_by_name(channel_name, ksession);
 100         if (kchan == NULL) {
 101                 ret = LTTNG_ERR_KERN_CHAN_NOT_FOUND;
 102                 goto error;
 103         }
 104
 105         /* Only if channel is enabled disable it. */
 106         if (kchan->enabled == 1) {
 107                 ret = kernel_disable_channel(kchan);
 108                 if (ret < 0 && ret != -EEXIST) {
 109                         ret = LTTNG_ERR_KERN_CHAN_DISABLE_FAIL;
 110                         goto error;
 111                 }
 112         }
 113
 114         ret = LTTNG_OK;
 115
 116 error:
 117         return ret;
 118 }
 119
 120 /*
 121  * Enable kernel channel of the kernel session.
 122  */
 123 int channel_kernel_enable(struct ltt_kernel_session *ksession,
 124                 struct ltt_kernel_channel *kchan)
 125 {
 126         int ret;
 127
 128         assert(ksession);
 129         assert(kchan);
 130
 131         if (kchan->enabled == 0) {
 132                 ret = kernel_enable_channel(kchan);
 133                 if (ret < 0) {
 134                         ret = LTTNG_ERR_KERN_CHAN_ENABLE_FAIL;
 135                         goto error;
 136                 }
 137         } else {
 138                 ret = LTTNG_ERR_KERN_CHAN_EXIST;
 139                 goto error;
 140         }
 141
 142         ret = LTTNG_OK;
 143
 144 error:
 145         return ret;
 146 }
 147
 148 /*
 149  * Create kernel channel of the kernel session and notify kernel thread.
 150  */
 151 int channel_kernel_create(struct ltt_kernel_session *ksession,
 152                 struct lttng_channel *attr, int kernel_pipe)
 153 {
 154         int ret;
 155         struct lttng_channel *defattr = NULL;
 156
 157         assert(ksession);
 158
 159         /* Creating channel attributes if needed */
 160         if (attr == NULL) {
 161                 defattr = channel_new_default_attr(LTTNG_DOMAIN_KERNEL);
 162                 if (defattr == NULL) {
 163                         ret = LTTNG_ERR_FATAL;
 164                         goto error;
 165                 }
 166                 attr = defattr;
 167         }
 168
 169         /* Channel not found, creating it */
 170         ret = kernel_create_channel(ksession, attr);
 171         if (ret < 0) {
 172                 ret = LTTNG_ERR_KERN_CHAN_FAIL;
 173                 goto error;
 174         }
 175
 176         /* Notify kernel thread that there is a new channel */
 177         ret = notify_thread_pipe(kernel_pipe);
 178         if (ret < 0) {
 179                 ret = LTTNG_ERR_FATAL;
 180                 goto error;
 181         }
 182
 183         ret = LTTNG_OK;
 184 error:
 185         free(defattr);
 186         return ret;
 187 }
 188
 189 /*
 190  * Enable UST channel for session and domain.
 191  */
 192 int channel_ust_enable(struct ltt_ust_session *usess,
 193                 struct ltt_ust_channel *uchan)
 194 {
 195         int ret = LTTNG_OK;
 196
 197         assert(usess);
 198         assert(uchan);
 199
 200         /* If already enabled, everything is OK */
 201         if (uchan->enabled) {
 202                 DBG3("Channel %s already enabled. Skipping", uchan->name);
 203                 ret = LTTNG_ERR_UST_CHAN_EXIST;
 204                 goto end;
 205         }
 206
 207         DBG2("Channel %s being enabled in UST domain", uchan->name);
 208
 209         /*
 210          * Enable channel for UST global domain on all applications. Ignore return
 211          * value here since whatever error we got, it means that the channel was
 212          * not created on one or many registered applications and we can not report
 213          * this to the user yet. However, at this stage, the channel was
 214          * successfully created on the session daemon side so the enable-channel
 215          * command is a success.
 216          */
 217         (void) ust_app_create_channel_glb(usess, uchan);
 218
 219         uchan->enabled = 1;
 220         DBG2("Channel %s enabled successfully", uchan->name);
 221
 222 end:
 223         return ret;
 224 }
 225
 226 /*
 227  * Create UST channel for session and domain.
 228  */
 229 int channel_ust_create(struct ltt_ust_session *usess,
 230                 struct lttng_channel *attr, enum lttng_buffer_type type)
 231 {
 232         int ret = LTTNG_OK;
 233         struct ltt_ust_channel *uchan = NULL;
 234         struct lttng_channel *defattr = NULL;
 235
 236         assert(usess);
 237
 238         /* Creating channel attributes if needed */
 239         if (attr == NULL) {
 240                 defattr = channel_new_default_attr(LTTNG_DOMAIN_UST);
 241                 if (defattr == NULL) {
 242                         ret = LTTNG_ERR_FATAL;
 243                         goto error;
 244                 }
 245                 attr = defattr;
 246         }
 247
 248         if (attr->attr.subbuf_size < DEFAULT_UST_CHANNEL_SUBBUF_SIZE) {
 249                 ret = LTTNG_ERR_INVALID;
 250                 goto error;
 251         }
 252
 253         /*
 254          * Validate UST buffer size and number of buffers: must both be power of 2
 255          * and nonzero. We validate right here for UST, because applications will
 256          * not report the error to the user (unlike kernel tracing).
 257          */
 258         if (!attr->attr.subbuf_size ||
 259                         (attr->attr.subbuf_size & (attr->attr.subbuf_size - 1))) {
 260                 ret = LTTNG_ERR_INVALID;
 261                 goto error;
 262         }
 263
 264         if (!attr->attr.num_subbuf ||
 265                         (attr->attr.num_subbuf & (attr->attr.num_subbuf - 1))) {
 266                 ret = LTTNG_ERR_INVALID;
 267                 goto error;
 268         }
 269
 270         if (attr->attr.output != LTTNG_EVENT_MMAP) {
 271                 ret = LTTNG_ERR_NOT_SUPPORTED;
 272                 goto error;
 273         }
 274
 275         /* Create UST channel */
 276         uchan = trace_ust_create_channel(attr, usess->pathname);
 277         if (uchan == NULL) {
 278                 ret = LTTNG_ERR_FATAL;
 279                 goto error;
 280         }
 281         uchan->enabled = 1;
 282         if (trace_ust_is_max_id(usess->used_channel_id)) {
 283                 ret = LTTNG_ERR_UST_CHAN_FAIL;
 284                 goto error;
 285         }
 286         uchan->id = trace_ust_get_next_chan_id(usess);
 287
 288         DBG2("Channel %s is being created for UST with buffer %d and id %" PRIu64,
 289                         uchan->name, type, uchan->id);
 290
 291         /* Flag session buffer type. */
 292         if (!usess->buffer_type_changed) {
 293                 usess->buffer_type = type;
 294                 usess->buffer_type_changed = 1;
 295         } else if (usess->buffer_type != type) {
 296                 /* Buffer type was already set. Refuse to create channel. */
 297                 ret = LTTNG_ERR_BUFFER_TYPE_MISMATCH;
 298                 goto error_free_chan;
 299         }
 300
 301         /* Enable channel for global domain */
 302         ret = ust_app_create_channel_glb(usess, uchan);
 303         if (ret < 0 && ret != -LTTNG_UST_ERR_EXIST) {
 304                 ret = LTTNG_ERR_UST_CHAN_FAIL;
 305                 goto error_free_chan;
 306         }
 307
 308         /* Adding the channel to the channel hash table. */
 309         rcu_read_lock();
 310         lttng_ht_add_unique_str(usess->domain_global.channels, &uchan->node);
 311         rcu_read_unlock();
 312
 313         DBG2("Channel %s created successfully", uchan->name);
 314
 315         free(defattr);
 316         return LTTNG_OK;
 317
 318 error_free_chan:
 319         /*
 320          * No need to remove the channel from the hash table because at this point
 321          * it was not added hence the direct call and no call_rcu().
 322          */
 323         trace_ust_destroy_channel(uchan);
 324 error:
 325         free(defattr);
 326         return ret;
 327 }
 328
 329 /*
 330  * Disable UST channel for session and domain.
 331  */
 332 int channel_ust_disable(struct ltt_ust_session *usess,
 333                 struct ltt_ust_channel *uchan)
 334 {
 335         int ret = LTTNG_OK;
 336
 337         assert(usess);
 338         assert(uchan);
 339
 340         /* Already disabled */
 341         if (uchan->enabled == 0) {
 342                 DBG2("Channel UST %s already disabled", uchan->name);
 343                 goto end;
 344         }
 345
 346         DBG2("Channel %s being disabled in UST global domain", uchan->name);
 347         /* Disable channel for global domain */
 348         ret = ust_app_disable_channel_glb(usess, uchan);
 349         if (ret < 0 && ret != -LTTNG_UST_ERR_EXIST) {
 350                 ret = LTTNG_ERR_UST_CHAN_DISABLE_FAIL;
 351                 goto error;
 352         }
 353
 354         uchan->enabled = 0;
 355
 356         DBG2("Channel %s disabled successfully", uchan->name);
 357
 358         return LTTNG_OK;
 359
 360 end:
 361 error:
 362         return ret;
 363 }