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