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 it
   5  * under the terms of the GNU General Public License as published by the Free
   6  * Software Foundation; only version 2 of the License.
   7  *
   8  * This program is distributed in the hope that it will be useful, but WITHOUT
   9  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  10  * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
  11  * more details.
  12  *
  13  * You should have received a copy of the GNU General Public License along with
  14  * this program; if not, write to the Free Software Foundation, Inc., 59 Temple
  15  * Place - Suite 330, Boston, MA  02111-1307, 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 = LTTCOMM_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 = LTTCOMM_KERN_CHAN_DISABLE_FAIL;
 100                         goto error;
 101                 }
 102         }
 103
 104         ret = LTTCOMM_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 = LTTCOMM_KERN_CHAN_ENABLE_FAIL;
 122                         goto error;
 123                 }
 124         }
 125
 126         ret = LTTCOMM_OK;
 127
 128 error:
 129         return ret;
 130 }
 131
 132 /*
 133  * Create kernel channel of the kernel session and notify kernel thread.
 134  */
 135 int channel_kernel_create(struct ltt_kernel_session *ksession,
 136                 struct lttng_channel *attr, int kernel_pipe)
 137 {
 138         int ret;
 139         struct lttng_channel *defattr = NULL;
 140
 141         /* Creating channel attributes if needed */
 142         if (attr == NULL) {
 143                 defattr = channel_new_default_attr(LTTNG_DOMAIN_KERNEL);
 144                 if (defattr == NULL) {
 145                         ret = LTTCOMM_FATAL;
 146                         goto error;
 147                 }
 148                 attr = defattr;
 149         }
 150
 151         /* Channel not found, creating it */
 152         ret = kernel_create_channel(ksession, attr, ksession->trace_path);
 153         if (ret < 0) {
 154                 ret = LTTCOMM_KERN_CHAN_FAIL;
 155                 goto error;
 156         }
 157
 158         /* Notify kernel thread that there is a new channel */
 159         ret = notify_thread_pipe(kernel_pipe);
 160         if (ret < 0) {
 161                 ret = LTTCOMM_FATAL;
 162                 goto error;
 163         }
 164
 165         ret = LTTCOMM_OK;
 166 error:
 167         free(defattr);
 168         return ret;
 169 }
 170
 171 /*
 172  * Enable UST channel for session and domain.
 173  */
 174 int channel_ust_enable(struct ltt_ust_session *usess, int domain,
 175                 struct ltt_ust_channel *uchan)
 176 {
 177         int ret = LTTCOMM_OK;
 178
 179         /* If already enabled, everything is OK */
 180         if (uchan->enabled) {
 181                 DBG3("Channel %s already enabled. Skipping", uchan->name);
 182                 goto end;
 183         }
 184
 185         switch (domain) {
 186         case LTTNG_DOMAIN_UST:
 187                 DBG2("Channel %s being enabled in UST global domain", uchan->name);
 188                 /* Enable channel for global domain */
 189                 ret = ust_app_enable_channel_glb(usess, uchan);
 190                 break;
 191 #if 0
 192         case LTTNG_DOMAIN_UST_PID:
 193         case LTTNG_DOMAIN_UST_PID_FOLLOW_CHILDREN:
 194         case LTTNG_DOMAIN_UST_EXEC_NAME:
 195 #endif
 196         default:
 197                 ret = LTTCOMM_UND;
 198                 goto error;
 199         }
 200
 201         if (ret < 0) {
 202                 if (ret != -EEXIST) {
 203                         ret = LTTCOMM_UST_CHAN_ENABLE_FAIL;
 204                         goto error;
 205                 } else {
 206                         ret = LTTCOMM_OK;
 207                 }
 208         }
 209
 210         uchan->enabled = 1;
 211         DBG2("Channel %s enabled successfully", uchan->name);
 212
 213 end:
 214 error:
 215         return ret;
 216 }
 217
 218 /*
 219  * Create UST channel for session and domain.
 220  */
 221 int channel_ust_create(struct ltt_ust_session *usess, int domain,
 222                 struct lttng_channel *attr)
 223 {
 224         int ret = LTTCOMM_OK;
 225         struct ltt_ust_channel *uchan = NULL;
 226         struct lttng_channel *defattr = NULL;
 227
 228         /* Creating channel attributes if needed */
 229         if (attr == NULL) {
 230                 defattr = channel_new_default_attr(domain);
 231                 if (defattr == NULL) {
 232                         ret = LTTCOMM_FATAL;
 233                         goto error;
 234                 }
 235                 attr = defattr;
 236         }
 237
 238         /*
 239          * Validate UST buffer size and number of buffers: must both be
 240          * power of 2 and nonzero. We validate right here for UST,
 241          * because applications will not report the error to the user
 242          * (unlike kernel tracing).
 243          */
 244         if (!attr->attr.subbuf_size || (attr->attr.subbuf_size & (attr->attr.subbuf_size - 1))) {
 245                 ret = LTTCOMM_INVALID;
 246                 goto error;
 247         }
 248         if (!attr->attr.num_subbuf || (attr->attr.num_subbuf & (attr->attr.num_subbuf - 1))) {
 249                 ret = LTTCOMM_INVALID;
 250                 goto error;
 251         }
 252
 253         /* Create UST channel */
 254         uchan = trace_ust_create_channel(attr, usess->pathname);
 255         if (uchan == NULL) {
 256                 ret = LTTCOMM_FATAL;
 257                 goto error;
 258         }
 259         uchan->enabled = 1;
 260
 261         switch (domain) {
 262         case LTTNG_DOMAIN_UST:
 263                 DBG2("Channel %s being created in UST global domain", uchan->name);
 264
 265                 /* Enable channel for global domain */
 266                 ret = ust_app_create_channel_glb(usess, uchan);
 267                 break;
 268 #if 0
 269         case LTTNG_DOMAIN_UST_PID:
 270         case LTTNG_DOMAIN_UST_PID_FOLLOW_CHILDREN:
 271         case LTTNG_DOMAIN_UST_EXEC_NAME:
 272 #endif
 273         default:
 274                 ret = LTTCOMM_UND;
 275                 goto error_free_chan;
 276         }
 277
 278         if (ret < 0 && ret != -EEXIST) {
 279                 ret = LTTCOMM_UST_CHAN_ENABLE_FAIL;
 280                 goto error_free_chan;
 281         }
 282
 283         /* Adding the channel to the channel hash table. */
 284         rcu_read_lock();
 285         lttng_ht_add_unique_str(usess->domain_global.channels, &uchan->node);
 286         rcu_read_unlock();
 287
 288         DBG2("Channel %s created successfully", uchan->name);
 289
 290         free(defattr);
 291         return LTTCOMM_OK;
 292
 293 error_free_chan:
 294         /*
 295          * No need to remove the channel from the hash table because at this point
 296          * it was not added hence the direct call and no call_rcu().
 297          */
 298         trace_ust_destroy_channel(uchan);
 299 error:
 300         free(defattr);
 301         return ret;
 302 }
 303
 304 /*
 305  * Disable UST channel for session and domain.
 306  */
 307 int channel_ust_disable(struct ltt_ust_session *usess, int domain,
 308                 struct ltt_ust_channel *uchan)
 309 {
 310         int ret = LTTCOMM_OK;
 311
 312         /* Already disabled */
 313         if (uchan->enabled == 0) {
 314                 DBG2("Channel UST %s already disabled", uchan->name);
 315                 goto end;
 316         }
 317
 318         /* Get the right channel's hashtable */
 319         switch (domain) {
 320         case LTTNG_DOMAIN_UST:
 321                 DBG2("Channel %s being disabled in UST global domain", uchan->name);
 322                 /* Disable channel for global domain */
 323                 ret = ust_app_disable_channel_glb(usess, uchan);
 324                 break;
 325 #if 0
 326         case LTTNG_DOMAIN_UST_PID_FOLLOW_CHILDREN:
 327         case LTTNG_DOMAIN_UST_EXEC_NAME:
 328         case LTTNG_DOMAIN_UST_PID:
 329 #endif
 330         default:
 331                 ret = LTTCOMM_UND;
 332                 goto error;
 333         }
 334
 335         if (ret < 0 && ret != -EEXIST) {
 336                 ret = LTTCOMM_UST_DISABLE_FAIL;
 337                 goto error;
 338         }
 339
 340         uchan->enabled = 0;
 341
 342         DBG2("Channel %s disabled successfully", uchan->name);
 343
 344         return LTTCOMM_OK;
 345
 346 end:
 347 error:
 348         return ret;
 349 }