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/sessiond-comm/sessiond-comm.h>
  23 #include <common/lttngerr.h>
  24 #include <common/lttng-share.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         case LTTNG_DOMAIN_UST_PID:
  63                 chan->attr.subbuf_size = DEFAULT_UST_CHANNEL_SUBBUF_SIZE;
  64                 chan->attr.num_subbuf = DEFAULT_UST_CHANNEL_SUBBUF_NUM;
  65                 chan->attr.output = DEFAULT_UST_CHANNEL_OUTPUT;
  66                 break;
  67         default:
  68                 goto error;     /* Not implemented */
  69         }
  70
  71         return chan;
  72
  73 error:
  74         free(chan);
  75 error_alloc:
  76         return NULL;
  77 }
  78
  79 /*
  80  * Disable kernel channel of the kernel session.
  81  */
  82 int channel_kernel_disable(struct ltt_kernel_session *ksession,
  83                 char *channel_name)
  84 {
  85         int ret;
  86         struct ltt_kernel_channel *kchan;
  87
  88         kchan = trace_kernel_get_channel_by_name(channel_name, ksession);
  89         if (kchan == NULL) {
  90                 ret = LTTCOMM_KERN_CHAN_NOT_FOUND;
  91                 goto error;
  92         } else if (kchan->enabled == 1) {
  93                 ret = kernel_disable_channel(kchan);
  94                 if (ret < 0 && ret != -EEXIST) {
  95                         ret = LTTCOMM_KERN_CHAN_DISABLE_FAIL;
  96                         goto error;
  97                 }
  98         }
  99
 100         ret = LTTCOMM_OK;
 101
 102 error:
 103         return ret;
 104 }
 105
 106 /*
 107  * Enable kernel channel of the kernel session.
 108  */
 109 int channel_kernel_enable(struct ltt_kernel_session *ksession,
 110                 struct ltt_kernel_channel *kchan)
 111 {
 112         int ret;
 113
 114         if (kchan->enabled == 0) {
 115                 ret = kernel_enable_channel(kchan);
 116                 if (ret < 0) {
 117                         ret = LTTCOMM_KERN_CHAN_ENABLE_FAIL;
 118                         goto error;
 119                 }
 120         }
 121
 122         ret = LTTCOMM_OK;
 123
 124 error:
 125         return ret;
 126 }
 127
 128 /*
 129  * Create kernel channel of the kernel session and notify kernel thread.
 130  */
 131 int channel_kernel_create(struct ltt_kernel_session *ksession,
 132                 struct lttng_channel *attr, int kernel_pipe)
 133 {
 134         int ret;
 135         struct lttng_channel *defattr = NULL;
 136
 137         /* Creating channel attributes if needed */
 138         if (attr == NULL) {
 139                 defattr = channel_new_default_attr(LTTNG_DOMAIN_KERNEL);
 140                 if (defattr == NULL) {
 141                         ret = LTTCOMM_FATAL;
 142                         goto error;
 143                 }
 144                 attr = defattr;
 145         }
 146
 147         /* Channel not found, creating it */
 148         ret = kernel_create_channel(ksession, attr, ksession->trace_path);
 149         if (ret < 0) {
 150                 ret = LTTCOMM_KERN_CHAN_FAIL;
 151                 goto error;
 152         }
 153
 154         /* Notify kernel thread that there is a new channel */
 155         ret = notify_thread_pipe(kernel_pipe);
 156         if (ret < 0) {
 157                 ret = LTTCOMM_FATAL;
 158                 goto error;
 159         }
 160
 161         ret = LTTCOMM_OK;
 162 error:
 163         free(defattr);
 164         return ret;
 165 }
 166
 167 /*
 168  * Enable UST channel for session and domain.
 169  */
 170 int channel_ust_enable(struct ltt_ust_session *usess, int domain,
 171                 struct ltt_ust_channel *uchan)
 172 {
 173         int ret = LTTCOMM_OK;
 174
 175         /* If already enabled, everything is OK */
 176         if (uchan->enabled) {
 177                 DBG3("Channel %s already enabled. Skipping", uchan->name);
 178                 goto end;
 179         }
 180
 181         switch (domain) {
 182         case LTTNG_DOMAIN_UST:
 183                 DBG2("Channel %s being enabled in UST global domain", uchan->name);
 184                 /* Enable channel for global domain */
 185                 ret = ust_app_enable_channel_glb(usess, uchan);
 186                 break;
 187         case LTTNG_DOMAIN_UST_PID:
 188         case LTTNG_DOMAIN_UST_PID_FOLLOW_CHILDREN:
 189         case LTTNG_DOMAIN_UST_EXEC_NAME:
 190                 ret = LTTCOMM_NOT_IMPLEMENTED;
 191                 goto error;
 192         }
 193
 194         if (ret < 0) {
 195                 if (ret != -EEXIST) {
 196                         ret = LTTCOMM_UST_CHAN_ENABLE_FAIL;
 197                         goto error;
 198                 } else {
 199                         ret = LTTCOMM_OK;
 200                 }
 201         }
 202
 203         uchan->enabled = 1;
 204         DBG2("Channel %s enabled successfully", uchan->name);
 205
 206 end:
 207 error:
 208         return ret;
 209 }
 210
 211 /*
 212  * Create UST channel for session and domain.
 213  */
 214 int channel_ust_create(struct ltt_ust_session *usess, int domain,
 215                 struct lttng_channel *attr)
 216 {
 217         int ret = LTTCOMM_OK;
 218         struct ltt_ust_channel *uchan = NULL;
 219         struct lttng_channel *defattr = NULL;
 220
 221         /* Creating channel attributes if needed */
 222         if (attr == NULL) {
 223                 defattr = channel_new_default_attr(domain);
 224                 if (defattr == NULL) {
 225                         ret = LTTCOMM_FATAL;
 226                         goto error;
 227                 }
 228                 attr = defattr;
 229         }
 230
 231         /* Create UST channel */
 232         uchan = trace_ust_create_channel(attr, usess->pathname);
 233         if (uchan == NULL) {
 234                 ret = LTTCOMM_FATAL;
 235                 goto error;
 236         }
 237         uchan->enabled = 1;
 238
 239         switch (domain) {
 240         case LTTNG_DOMAIN_UST:
 241                 DBG2("Channel %s being created in UST global domain", uchan->name);
 242
 243                 /* Enable channel for global domain */
 244                 ret = ust_app_create_channel_glb(usess, uchan);
 245                 break;
 246         case LTTNG_DOMAIN_UST_PID:
 247         case LTTNG_DOMAIN_UST_PID_FOLLOW_CHILDREN:
 248         case LTTNG_DOMAIN_UST_EXEC_NAME:
 249         default:
 250                 ret = LTTCOMM_NOT_IMPLEMENTED;
 251                 goto error_free_chan;
 252         }
 253
 254         if (ret < 0 && ret != -EEXIST) {
 255                 ret = LTTCOMM_UST_CHAN_ENABLE_FAIL;
 256                 goto error_free_chan;
 257         }
 258
 259         /* Adding the channel to the channel hash table. */
 260         rcu_read_lock();
 261         lttng_ht_add_unique_str(usess->domain_global.channels, &uchan->node);
 262         rcu_read_unlock();
 263
 264         DBG2("Channel %s created successfully", uchan->name);
 265
 266         free(defattr);
 267         return LTTCOMM_OK;
 268
 269 error_free_chan:
 270         /*
 271          * No need to remove the channel from the hash table because at this point
 272          * it was not added hence the direct call and no call_rcu().
 273          */
 274         trace_ust_destroy_channel(uchan);
 275 error:
 276         free(defattr);
 277         return ret;
 278 }
 279
 280 /*
 281  * Disable UST channel for session and domain.
 282  */
 283 int channel_ust_disable(struct ltt_ust_session *usess, int domain,
 284                 struct ltt_ust_channel *uchan)
 285 {
 286         int ret = LTTCOMM_OK;
 287
 288         /* Already disabled */
 289         if (uchan->enabled == 0) {
 290                 DBG2("Channel UST %s already disabled", uchan->name);
 291                 goto end;
 292         }
 293
 294         /* Get the right channel's hashtable */
 295         switch (domain) {
 296         case LTTNG_DOMAIN_UST:
 297                 DBG2("Channel %s being disabled in UST global domain", uchan->name);
 298                 /* Disable channel for global domain */
 299                 ret = ust_app_disable_channel_glb(usess, uchan);
 300                 break;
 301         case LTTNG_DOMAIN_UST_PID_FOLLOW_CHILDREN:
 302         case LTTNG_DOMAIN_UST_EXEC_NAME:
 303         case LTTNG_DOMAIN_UST_PID:
 304                 ret = LTTCOMM_NOT_IMPLEMENTED;
 305                 goto error;
 306         }
 307
 308         if (ret < 0 && ret != -EEXIST) {
 309                 ret = LTTCOMM_UST_DISABLE_FAIL;
 310                 goto error;
 311         }
 312
 313         uchan->enabled = 0;
 314
 315         DBG2("Channel %s disabled successfully", uchan->name);
 316
 317         return LTTCOMM_OK;
 318
 319 end:
 320 error:
 321         return ret;
 322 }