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