src/bin/lttng-sessiond/snapshot.c

   1 /*
   2  * Copyright (C) 2013 David Goulet <dgoulet@efficios.com>
   3  *
   4  * SPDX-License-Identifier: GPL-2.0-only
   5  *
   6  */
   7
   8 #define _LGPL_SOURCE
   9 #include <assert.h>
  10 #include <inttypes.h>
  11 #include <string.h>
  12 #include <urcu/uatomic.h>
  13
  14 #include <common/defaults.h>
  15
  16 #include "snapshot.h"
  17 #include "utils.h"
  18
  19 /*
  20  * Return the atomically incremented value of next_output_id.
  21  */
  22 static inline unsigned long get_next_output_id(struct snapshot *snapshot)
  23 {
  24         return uatomic_add_return(&snapshot->next_output_id, 1);
  25 }
  26
  27 /*
  28  * Initialized snapshot output with the given values.
  29  *
  30  * Return 0 on success or else a negative value.
  31  */
  32 static int output_init(const struct ltt_session *session,
  33                 uint64_t max_size, const char *name,
  34                 struct lttng_uri *uris, size_t nb_uri,
  35                 struct consumer_output *consumer, struct snapshot_output *output,
  36                 struct snapshot *snapshot)
  37 {
  38         int ret = 0, i;
  39
  40         memset(output, 0, sizeof(struct snapshot_output));
  41
  42         /*
  43          * max_size of -1ULL means unset. Set to default (unlimited).
  44          */
  45         if (max_size == (uint64_t) -1ULL) {
  46                 max_size = 0;
  47         }
  48         output->max_size = max_size;
  49
  50         if (snapshot) {
  51                 output->id = get_next_output_id(snapshot);
  52         }
  53         lttng_ht_node_init_ulong(&output->node, (unsigned long) output->id);
  54
  55         if (name && name[0] != '\0') {
  56                 if (lttng_strncpy(output->name, name, sizeof(output->name))) {
  57                         ret = -LTTNG_ERR_INVALID;
  58                         goto error;
  59                 }
  60         } else {
  61                 /* Set default name. */
  62                 ret = snprintf(output->name, sizeof(output->name), "%s-%" PRIu32,
  63                                 DEFAULT_SNAPSHOT_NAME, output->id);
  64                 if (ret < 0) {
  65                         ret = -ENOMEM;
  66                         goto error;
  67                 }
  68         }
  69
  70         if (!consumer) {
  71                 goto end;
  72         }
  73
  74         output->consumer = consumer_copy_output(consumer);
  75         if (!output->consumer) {
  76                 ret = -ENOMEM;
  77                 goto error;
  78         }
  79         output->consumer->snapshot = 1;
  80
  81         /* No URL given. */
  82         if (nb_uri == 0) {
  83                 ret = 0;
  84                 goto end;
  85         }
  86
  87         if (uris[0].dtype == LTTNG_DST_PATH) {
  88                 memset(output->consumer->dst.session_root_path, 0,
  89                                 sizeof(output->consumer->dst.session_root_path));
  90                 if (lttng_strncpy(output->consumer->dst.session_root_path,
  91                                 uris[0].dst.path,
  92                                 sizeof(output->consumer->dst.session_root_path))) {
  93                         ret = -LTTNG_ERR_INVALID;
  94                         goto error;
  95                 }
  96                 output->consumer->type = CONSUMER_DST_LOCAL;
  97                 ret = 0;
  98                 goto end;
  99         }
 100
 101         if (nb_uri != 2) {
 102                 /* Absolutely needs two URIs for network. */
 103                 ret = -LTTNG_ERR_INVALID;
 104                 goto error;
 105         }
 106
 107         for (i = 0; i < nb_uri; i ++) {
 108                 /* Network URIs */
 109                 ret = consumer_set_network_uri(session, output->consumer,
 110                                 &uris[i]);
 111                 if (ret < 0) {
 112                         goto error;
 113                 }
 114         }
 115
 116 error:
 117 end:
 118         return ret;
 119 }
 120
 121 /*
 122  * Initialize a snapshot output object using the given parameters and URI(s).
 123  * The name value and uris can be NULL.
 124  *
 125  * Return 0 on success or else a negative value.
 126  */
 127 int snapshot_output_init_with_uri(const struct ltt_session *session,
 128                 uint64_t max_size, const char *name,
 129                 struct lttng_uri *uris, size_t nb_uri,
 130                 struct consumer_output *consumer, struct snapshot_output *output,
 131                 struct snapshot *snapshot)
 132 {
 133         return output_init(session, max_size, name, uris, nb_uri, consumer,
 134                         output, snapshot);
 135 }
 136
 137 /*
 138  * Initialize a snapshot output object using the given parameters. The name
 139  * value and url can be NULL.
 140  *
 141  * Return 0 on success or else a negative value.
 142  */
 143 int snapshot_output_init(const struct ltt_session *session,
 144                 uint64_t max_size, const char *name,
 145                 const char *ctrl_url, const char *data_url,
 146                 struct consumer_output *consumer, struct snapshot_output *output,
 147                 struct snapshot *snapshot)
 148 {
 149         int ret = 0, nb_uri;
 150         struct lttng_uri *uris = NULL;
 151
 152         /* Create an array of URIs from URLs. */
 153         nb_uri = uri_parse_str_urls(ctrl_url, data_url, &uris);
 154         if (nb_uri < 0) {
 155                 ret = nb_uri;
 156                 goto error;
 157         }
 158
 159         ret = output_init(session, max_size, name, uris, nb_uri, consumer,
 160                         output, snapshot);
 161
 162 error:
 163         free(uris);
 164         return ret;
 165 }
 166
 167 struct snapshot_output *snapshot_output_alloc(void)
 168 {
 169         return zmalloc(sizeof(struct snapshot_output));
 170 }
 171
 172 /*
 173  * Delete output from the snapshot object.
 174  */
 175 void snapshot_delete_output(struct snapshot *snapshot,
 176                 struct snapshot_output *output)
 177 {
 178         int ret;
 179         struct lttng_ht_iter iter;
 180
 181         assert(snapshot);
 182         assert(snapshot->output_ht);
 183         assert(output);
 184
 185         iter.iter.node = &output->node.node;
 186         rcu_read_lock();
 187         ret = lttng_ht_del(snapshot->output_ht, &iter);
 188         rcu_read_unlock();
 189         assert(!ret);
 190         /*
 191          * This is safe because the ownership of a snapshot object is in a session
 192          * for which the session lock need to be acquired to read and modify it.
 193          */
 194         snapshot->nb_output--;
 195 }
 196
 197 /*
 198  * Add output object to the snapshot.
 199  */
 200 void snapshot_add_output(struct snapshot *snapshot,
 201                 struct snapshot_output *output)
 202 {
 203         assert(snapshot);
 204         assert(snapshot->output_ht);
 205         assert(output);
 206
 207         rcu_read_lock();
 208         lttng_ht_add_unique_ulong(snapshot->output_ht, &output->node);
 209         rcu_read_unlock();
 210         /*
 211          * This is safe because the ownership of a snapshot object is in a session
 212          * for which the session lock need to be acquired to read and modify it.
 213          */
 214         snapshot->nb_output++;
 215 }
 216
 217 /*
 218  * Destroy and free a snapshot output object.
 219  */
 220 void snapshot_output_destroy(struct snapshot_output *obj)
 221 {
 222         assert(obj);
 223
 224         if (obj->consumer) {
 225                 consumer_output_send_destroy_relayd(obj->consumer);
 226                 consumer_output_put(obj->consumer);
 227         }
 228         free(obj);
 229 }
 230
 231 /*
 232  * RCU read side lock MUST be acquired before calling this since the returned
 233  * pointer is in a RCU hash table.
 234  *
 235  * Return the reference on success or else NULL.
 236  */
 237 struct snapshot_output *snapshot_find_output_by_name(const char *name,
 238                 struct snapshot *snapshot)
 239 {
 240         struct lttng_ht_iter iter;
 241         struct snapshot_output *output = NULL;
 242
 243         assert(snapshot);
 244         assert(name);
 245
 246         cds_lfht_for_each_entry(snapshot->output_ht->ht, &iter.iter, output,
 247                 node.node) {
 248                 if (!strncmp(output->name, name, strlen(name))) {
 249                         return output;
 250                 }
 251         }
 252
 253         /* Not found */
 254         return NULL;
 255 }
 256
 257 /*
 258  * RCU read side lock MUST be acquired before calling this since the returned
 259  * pointer is in a RCU hash table.
 260  *
 261  * Return the reference on success or else NULL.
 262  */
 263 struct snapshot_output *snapshot_find_output_by_id(uint32_t id,
 264                 struct snapshot *snapshot)
 265 {
 266         struct lttng_ht_node_ulong *node;
 267         struct lttng_ht_iter iter;
 268         struct snapshot_output *output = NULL;
 269
 270         assert(snapshot);
 271
 272         lttng_ht_lookup(snapshot->output_ht, (void *)((unsigned long) id), &iter);
 273         node = lttng_ht_iter_get_node_ulong(&iter);
 274         if (!node) {
 275                 DBG3("Snapshot output not found with id %" PRId32, id);
 276                 goto error;
 277         }
 278         output = caa_container_of(node, struct snapshot_output, node);
 279
 280 error:
 281         return output;
 282 }
 283
 284 /*
 285  * Initialized a snapshot object that was already allocated.
 286  *
 287  * Return 0 on success or else a negative errno value.
 288  */
 289 int snapshot_init(struct snapshot *obj)
 290 {
 291         int ret;
 292
 293         assert(obj);
 294
 295         memset(obj, 0, sizeof(struct snapshot));
 296
 297         obj->output_ht = lttng_ht_new(0, LTTNG_HT_TYPE_ULONG);
 298         if (!obj->output_ht) {
 299                 ret = -ENOMEM;
 300                 goto error;
 301         }
 302
 303         ret = 0;
 304
 305 error:
 306         return ret;
 307 }
 308
 309 /*
 310  * Destroy snapshot object but the pointer is not freed so it's safe to pass a
 311  * static reference.
 312  */
 313 void snapshot_destroy(struct snapshot *obj)
 314 {
 315         struct lttng_ht_iter iter;
 316         struct snapshot_output *output;
 317
 318         if (!obj->output_ht) {
 319                 return;
 320         }
 321
 322         rcu_read_lock();
 323         cds_lfht_for_each_entry(obj->output_ht->ht, &iter.iter, output,
 324                         node.node) {
 325                 snapshot_delete_output(obj, output);
 326                 snapshot_output_destroy(output);
 327         }
 328         rcu_read_unlock();
 329         ht_cleanup_push(obj->output_ht);
 330 }