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