src/bin/lttng-sessiond/snapshot.c

   1 /*
   2  * Copyright (C) 2013 - David Goulet <dgoulet@efficios.com>
   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, version 2 only, as
   6  * published by the Free Software Foundation.
   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., 51
  15  * Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  16  */
  17
  18 #define _GNU_SOURCE
  19 #define _LGPL_SOURCE
  20 #include <assert.h>
  21 #include <inttypes.h>
  22 #include <string.h>
  23 #include <urcu/uatomic.h>
  24
  25 #include <common/defaults.h>
  26
  27 #include "snapshot.h"
  28 #include "utils.h"
  29
  30 /*
  31  * Return the atomically incremented value of next_output_id.
  32  */
  33 static inline unsigned long get_next_output_id(struct snapshot *snapshot)
  34 {
  35         return uatomic_add_return(&snapshot->next_output_id, 1);
  36 }
  37
  38 /*
  39  * Initialized snapshot output with the given values.
  40  *
  41  * Return 0 on success or else a negative value.
  42  */
  43 static int output_init(uint64_t max_size, const char *name,
  44                 struct lttng_uri *uris, size_t nb_uri,
  45                 struct consumer_output *consumer, struct snapshot_output *output,
  46                 struct snapshot *snapshot)
  47 {
  48         int ret = 0, i;
  49
  50         memset(output, 0, sizeof(struct snapshot_output));
  51
  52         /*
  53          * max_size of -1ULL means unset. Set to default (unlimited).
  54          */
  55         if (max_size == (uint64_t) -1ULL) {
  56                 max_size = 0;
  57         }
  58         output->max_size = max_size;
  59
  60         if (snapshot) {
  61                 output->id = get_next_output_id(snapshot);
  62         }
  63         lttng_ht_node_init_ulong(&output->node, (unsigned long) output->id);
  64
  65         if (name && name[0] != '\0') {
  66                 if (lttng_strncpy(output->name, name, sizeof(output->name))) {
  67                         ret = -LTTNG_ERR_INVALID;
  68                         goto error;
  69                 }
  70         } else {
  71                 /* Set default name. */
  72                 ret = snprintf(output->name, sizeof(output->name), "%s-%" PRIu32,
  73                                 DEFAULT_SNAPSHOT_NAME, output->id);
  74                 if (ret < 0) {
  75                         ret = -ENOMEM;
  76                         goto error;
  77                 }
  78         }
  79
  80         if (!consumer) {
  81                 goto end;
  82         }
  83
  84         output->consumer = consumer_copy_output(consumer);
  85         if (!output->consumer) {
  86                 ret = -ENOMEM;
  87                 goto error;
  88         }
  89         output->consumer->snapshot = 1;
  90
  91         /* No URL given. */
  92         if (nb_uri == 0) {
  93                 ret = 0;
  94                 goto end;
  95         }
  96
  97         if (uris[0].dtype == LTTNG_DST_PATH) {
  98                 memset(output->consumer->dst.trace_path, 0,
  99                                 sizeof(output->consumer->dst.trace_path));
 100                 if (lttng_strncpy(output->consumer->dst.trace_path,
 101                                 uris[0].dst.path,
 102                                 sizeof(output->consumer->dst.trace_path))) {
 103                         ret = -LTTNG_ERR_INVALID;
 104                         goto error;
 105                 }
 106                 output->consumer->type = CONSUMER_DST_LOCAL;
 107                 ret = 0;
 108                 goto end;
 109         }
 110
 111         if (nb_uri != 2) {
 112                 /* Absolutely needs two URIs for network. */
 113                 ret = -LTTNG_ERR_INVALID;
 114                 goto error;
 115         }
 116
 117         for (i = 0; i < nb_uri; i ++) {
 118                 /* Network URIs */
 119                 ret = consumer_set_network_uri(output->consumer, &uris[i]);
 120                 if (ret < 0) {
 121                         goto error;
 122                 }
 123         }
 124
 125 error:
 126 end:
 127         return ret;
 128 }
 129
 130 /*
 131  * Initialize a snapshot output object using the given parameters and URI(s).
 132  * The name value and uris can be NULL.
 133  *
 134  * Return 0 on success or else a negative value.
 135  */
 136 int snapshot_output_init_with_uri(uint64_t max_size, const char *name,
 137                 struct lttng_uri *uris, size_t nb_uri,
 138                 struct consumer_output *consumer, struct snapshot_output *output,
 139                 struct snapshot *snapshot)
 140 {
 141         return output_init(max_size, name, uris, nb_uri, consumer, output,
 142                         snapshot);
 143 }
 144
 145 /*
 146  * Initialize a snapshot output object using the given parameters. The name
 147  * value and url can be NULL.
 148  *
 149  * Return 0 on success or else a negative value.
 150  */
 151 int snapshot_output_init(uint64_t max_size, const char *name,
 152                 const char *ctrl_url, const char *data_url,
 153                 struct consumer_output *consumer, struct snapshot_output *output,
 154                 struct snapshot *snapshot)
 155 {
 156         int ret = 0, nb_uri;
 157         struct lttng_uri *uris = NULL;
 158
 159         /* Create an array of URIs from URLs. */
 160         nb_uri = uri_parse_str_urls(ctrl_url, data_url, &uris);
 161         if (nb_uri < 0) {
 162                 ret = nb_uri;
 163                 goto error;
 164         }
 165
 166         ret = output_init(max_size, name, uris, nb_uri, consumer, output,
 167                         snapshot);
 168
 169 error:
 170         free(uris);
 171         return ret;
 172 }
 173
 174 struct snapshot_output *snapshot_output_alloc(void)
 175 {
 176         return zmalloc(sizeof(struct snapshot_output));
 177 }
 178
 179 /*
 180  * Delete output from the snapshot object.
 181  */
 182 void snapshot_delete_output(struct snapshot *snapshot,
 183                 struct snapshot_output *output)
 184 {
 185         int ret;
 186         struct lttng_ht_iter iter;
 187
 188         assert(snapshot);
 189         assert(snapshot->output_ht);
 190         assert(output);
 191
 192         iter.iter.node = &output->node.node;
 193         rcu_read_lock();
 194         ret = lttng_ht_del(snapshot->output_ht, &iter);
 195         rcu_read_unlock();
 196         assert(!ret);
 197         /*
 198          * This is safe because the ownership of a snapshot object is in a session
 199          * for which the session lock need to be acquired to read and modify it.
 200          */
 201         snapshot->nb_output--;
 202 }
 203
 204 /*
 205  * Add output object to the snapshot.
 206  */
 207 void snapshot_add_output(struct snapshot *snapshot,
 208                 struct snapshot_output *output)
 209 {
 210         assert(snapshot);
 211         assert(snapshot->output_ht);
 212         assert(output);
 213
 214         rcu_read_lock();
 215         lttng_ht_add_unique_ulong(snapshot->output_ht, &output->node);
 216         rcu_read_unlock();
 217         /*
 218          * This is safe because the ownership of a snapshot object is in a session
 219          * for which the session lock need to be acquired to read and modify it.
 220          */
 221         snapshot->nb_output++;
 222 }
 223
 224 /*
 225  * Destroy and free a snapshot output object.
 226  */
 227 void snapshot_output_destroy(struct snapshot_output *obj)
 228 {
 229         assert(obj);
 230
 231         if (obj->consumer) {
 232                 consumer_output_send_destroy_relayd(obj->consumer);
 233                 consumer_output_put(obj->consumer);
 234         }
 235         free(obj);
 236 }
 237
 238 /*
 239  * RCU read side lock MUST be acquired before calling this since the returned
 240  * pointer is in a RCU hash table.
 241  *
 242  * Return the reference on success or else NULL.
 243  */
 244 struct snapshot_output *snapshot_find_output_by_name(const char *name,
 245                 struct snapshot *snapshot)
 246 {
 247         struct lttng_ht_iter iter;
 248         struct snapshot_output *output = NULL;
 249
 250         assert(snapshot);
 251         assert(name);
 252
 253         cds_lfht_for_each_entry(snapshot->output_ht->ht, &iter.iter, output,
 254                 node.node) {
 255                 if (!strncmp(output->name, name, strlen(name))) {
 256                         return output;
 257                 }
 258         }
 259
 260         /* Not found */
 261         return NULL;
 262 }
 263
 264 /*
 265  * RCU read side lock MUST be acquired before calling this since the returned
 266  * pointer is in a RCU hash table.
 267  *
 268  * Return the reference on success or else NULL.
 269  */
 270 struct snapshot_output *snapshot_find_output_by_id(uint32_t id,
 271                 struct snapshot *snapshot)
 272 {
 273         struct lttng_ht_node_ulong *node;
 274         struct lttng_ht_iter iter;
 275         struct snapshot_output *output = NULL;
 276
 277         assert(snapshot);
 278
 279         lttng_ht_lookup(snapshot->output_ht, (void *)((unsigned long) id), &iter);
 280         node = lttng_ht_iter_get_node_ulong(&iter);
 281         if (!node) {
 282                 DBG3("Snapshot output not found with id %" PRId32, id);
 283                 goto error;
 284         }
 285         output = caa_container_of(node, struct snapshot_output, node);
 286
 287 error:
 288         return output;
 289 }
 290
 291 /*
 292  * Initialized a snapshot object that was already allocated.
 293  *
 294  * Return 0 on success or else a negative errno value.
 295  */
 296 int snapshot_init(struct snapshot *obj)
 297 {
 298         int ret;
 299
 300         assert(obj);
 301
 302         memset(obj, 0, sizeof(struct snapshot));
 303
 304         obj->output_ht = lttng_ht_new(0, LTTNG_HT_TYPE_ULONG);
 305         if (!obj->output_ht) {
 306                 ret = -ENOMEM;
 307                 goto error;
 308         }
 309
 310         ret = 0;
 311
 312 error:
 313         return ret;
 314 }
 315
 316 /*
 317  * Destroy snapshot object but the pointer is not freed so it's safe to pass a
 318  * static reference.
 319  */
 320 void snapshot_destroy(struct snapshot *obj)
 321 {
 322         struct lttng_ht_iter iter;
 323         struct snapshot_output *output;
 324
 325         assert(obj);
 326
 327         rcu_read_lock();
 328         cds_lfht_for_each_entry(obj->output_ht->ht, &iter.iter, output,
 329                         node.node) {
 330                 snapshot_delete_output(obj, output);
 331                 snapshot_output_destroy(output);
 332         }
 333         rcu_read_unlock();
 334         ht_cleanup_push(obj->output_ht);
 335 }