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