| 1 | /* |
| 2 | * ltt-probes.c |
| 3 | * |
| 4 | * Copyright 2010 (c) - Mathieu Desnoyers <mathieu.desnoyers@efficios.com> |
| 5 | * |
| 6 | * Holds LTTng probes registry. |
| 7 | * |
| 8 | * Dual LGPL v2.1/GPL v2 license. |
| 9 | */ |
| 10 | |
| 11 | #include <string.h> |
| 12 | #include <errno.h> |
| 13 | #include <urcu/list.h> |
| 14 | #include <urcu/hlist.h> |
| 15 | #include <lttng/ust-events.h> |
| 16 | #include <assert.h> |
| 17 | #include <helper.h> |
| 18 | |
| 19 | #include "ltt-tracer-core.h" |
| 20 | #include "jhash.h" |
| 21 | #include "error.h" |
| 22 | |
| 23 | /* |
| 24 | * probe list is protected by ust_lock()/ust_unlock(). |
| 25 | */ |
| 26 | static CDS_LIST_HEAD(probe_list); |
| 27 | |
| 28 | /* |
| 29 | * Loglevel hash table, containing the active loglevels. |
| 30 | * Protected by ust lock. |
| 31 | */ |
| 32 | #define LOGLEVEL_HASH_BITS 6 |
| 33 | #define LOGLEVEL_TABLE_SIZE (1 << LOGLEVEL_HASH_BITS) |
| 34 | static struct cds_hlist_head loglevel_table[LOGLEVEL_TABLE_SIZE]; |
| 35 | |
| 36 | static |
| 37 | const struct lttng_probe_desc *find_provider(const char *provider) |
| 38 | { |
| 39 | struct lttng_probe_desc *iter; |
| 40 | |
| 41 | cds_list_for_each_entry(iter, &probe_list, head) { |
| 42 | if (!strcmp(iter->provider, provider)) |
| 43 | return iter; |
| 44 | } |
| 45 | return NULL; |
| 46 | } |
| 47 | |
| 48 | static |
| 49 | const struct lttng_event_desc *find_event(const char *name) |
| 50 | { |
| 51 | struct lttng_probe_desc *probe_desc; |
| 52 | int i; |
| 53 | |
| 54 | cds_list_for_each_entry(probe_desc, &probe_list, head) { |
| 55 | for (i = 0; i < probe_desc->nr_events; i++) { |
| 56 | if (!strcmp(probe_desc->event_desc[i]->name, name)) |
| 57 | return probe_desc->event_desc[i]; |
| 58 | } |
| 59 | } |
| 60 | return NULL; |
| 61 | } |
| 62 | |
| 63 | int ltt_probe_register(struct lttng_probe_desc *desc) |
| 64 | { |
| 65 | struct lttng_probe_desc *iter; |
| 66 | int ret = 0; |
| 67 | int i; |
| 68 | |
| 69 | ust_lock(); |
| 70 | if (find_provider(desc->provider)) { |
| 71 | ret = -EEXIST; |
| 72 | goto end; |
| 73 | } |
| 74 | /* |
| 75 | * TODO: This is O(N^2). Turn into a hash table when probe registration |
| 76 | * overhead becomes an issue. |
| 77 | */ |
| 78 | for (i = 0; i < desc->nr_events; i++) { |
| 79 | if (find_event(desc->event_desc[i]->name)) { |
| 80 | ret = -EEXIST; |
| 81 | goto end; |
| 82 | } |
| 83 | } |
| 84 | |
| 85 | /* |
| 86 | * We sort the providers by struct lttng_probe_desc pointer |
| 87 | * address. |
| 88 | */ |
| 89 | cds_list_for_each_entry_reverse(iter, &probe_list, head) { |
| 90 | BUG_ON(iter == desc); /* Should never be in the list twice */ |
| 91 | if (iter < desc) { |
| 92 | /* We belong to the location right after iter. */ |
| 93 | cds_list_add(&desc->head, &iter->head); |
| 94 | goto desc_added; |
| 95 | } |
| 96 | } |
| 97 | /* We should be added at the head of the list */ |
| 98 | cds_list_add(&desc->head, &probe_list); |
| 99 | desc_added: |
| 100 | |
| 101 | /* |
| 102 | * fix the events awaiting probe load. |
| 103 | */ |
| 104 | for (i = 0; i < desc->nr_events; i++) { |
| 105 | ret = pending_probe_fix_events(desc->event_desc[i]); |
| 106 | assert(!ret); |
| 107 | } |
| 108 | end: |
| 109 | ust_unlock(); |
| 110 | return ret; |
| 111 | } |
| 112 | |
| 113 | void ltt_probe_unregister(struct lttng_probe_desc *desc) |
| 114 | { |
| 115 | ust_lock(); |
| 116 | cds_list_del(&desc->head); |
| 117 | ust_unlock(); |
| 118 | } |
| 119 | |
| 120 | /* |
| 121 | * called with UST lock held. |
| 122 | */ |
| 123 | const struct lttng_event_desc *ltt_event_get(const char *name) |
| 124 | { |
| 125 | const struct lttng_event_desc *event; |
| 126 | |
| 127 | event = find_event(name); |
| 128 | if (!event) |
| 129 | return NULL; |
| 130 | return event; |
| 131 | } |
| 132 | |
| 133 | void ltt_event_put(const struct lttng_event_desc *event) |
| 134 | { |
| 135 | } |
| 136 | |
| 137 | void ltt_probes_prune_event_list(struct lttng_ust_tracepoint_list *list) |
| 138 | { |
| 139 | struct tp_list_entry *list_entry, *tmp; |
| 140 | |
| 141 | cds_list_for_each_entry_safe(list_entry, tmp, &list->head, head) { |
| 142 | cds_list_del(&list_entry->head); |
| 143 | free(list_entry); |
| 144 | } |
| 145 | } |
| 146 | |
| 147 | /* |
| 148 | * called with UST lock held. |
| 149 | */ |
| 150 | int ltt_probes_get_event_list(struct lttng_ust_tracepoint_list *list) |
| 151 | { |
| 152 | struct lttng_probe_desc *probe_desc; |
| 153 | int i; |
| 154 | |
| 155 | CDS_INIT_LIST_HEAD(&list->head); |
| 156 | cds_list_for_each_entry(probe_desc, &probe_list, head) { |
| 157 | for (i = 0; i < probe_desc->nr_events; i++) { |
| 158 | struct tp_list_entry *list_entry; |
| 159 | |
| 160 | list_entry = zmalloc(sizeof(*list_entry)); |
| 161 | if (!list_entry) |
| 162 | goto err_nomem; |
| 163 | cds_list_add(&list_entry->head, &list->head); |
| 164 | strncpy(list_entry->tp.name, |
| 165 | probe_desc->event_desc[i]->name, |
| 166 | LTTNG_UST_SYM_NAME_LEN); |
| 167 | list_entry->tp.name[LTTNG_UST_SYM_NAME_LEN - 1] = '\0'; |
| 168 | if (!probe_desc->event_desc[i]->loglevel) { |
| 169 | list_entry->tp.loglevel[0] = '\0'; |
| 170 | list_entry->tp.loglevel_value = 0; |
| 171 | } else { |
| 172 | strncpy(list_entry->tp.loglevel, |
| 173 | (*probe_desc->event_desc[i]->loglevel)->identifier, |
| 174 | LTTNG_UST_SYM_NAME_LEN); |
| 175 | list_entry->tp.loglevel[LTTNG_UST_SYM_NAME_LEN - 1] = '\0'; |
| 176 | list_entry->tp.loglevel_value = |
| 177 | (*probe_desc->event_desc[i]->loglevel)->value; |
| 178 | } |
| 179 | } |
| 180 | } |
| 181 | if (cds_list_empty(&list->head)) |
| 182 | list->iter = NULL; |
| 183 | else |
| 184 | list->iter = |
| 185 | cds_list_first_entry(&list->head, struct tp_list_entry, head); |
| 186 | return 0; |
| 187 | |
| 188 | err_nomem: |
| 189 | ltt_probes_prune_event_list(list); |
| 190 | return -ENOMEM; |
| 191 | } |
| 192 | |
| 193 | /* |
| 194 | * Return current iteration position, advance internal iterator to next. |
| 195 | * Return NULL if end of list. |
| 196 | */ |
| 197 | struct lttng_ust_tracepoint_iter * |
| 198 | lttng_ust_tracepoint_list_get_iter_next(struct lttng_ust_tracepoint_list *list) |
| 199 | { |
| 200 | struct tp_list_entry *entry; |
| 201 | |
| 202 | if (!list->iter) |
| 203 | return NULL; |
| 204 | entry = list->iter; |
| 205 | if (entry->head.next == &list->head) |
| 206 | list->iter = NULL; |
| 207 | else |
| 208 | list->iter = cds_list_entry(entry->head.next, |
| 209 | struct tp_list_entry, head); |
| 210 | return &entry->tp; |
| 211 | } |
| 212 | |
| 213 | /* |
| 214 | * Get loglevel if the loglevel is present in the loglevel hash table. |
| 215 | * Must be called with ust lock held. |
| 216 | * Returns NULL if not present. |
| 217 | */ |
| 218 | struct loglevel_entry *get_loglevel(const char *name) |
| 219 | { |
| 220 | struct cds_hlist_head *head; |
| 221 | struct cds_hlist_node *node; |
| 222 | struct loglevel_entry *e; |
| 223 | uint32_t hash = jhash(name, strlen(name), 0); |
| 224 | |
| 225 | head = &loglevel_table[hash & (LOGLEVEL_TABLE_SIZE - 1)]; |
| 226 | cds_hlist_for_each_entry(e, node, head, hlist) { |
| 227 | if (!strcmp(name, e->name)) |
| 228 | return e; |
| 229 | } |
| 230 | return NULL; |
| 231 | } |
| 232 | |
| 233 | /* |
| 234 | * marshall all probes/all events and create those that fit the |
| 235 | * loglevel. Add them to the events list as created. |
| 236 | */ |
| 237 | static |
| 238 | void _probes_create_loglevel_events(struct loglevel_entry *entry, |
| 239 | struct session_loglevel *loglevel) |
| 240 | { |
| 241 | struct lttng_probe_desc *probe_desc; |
| 242 | int i; |
| 243 | |
| 244 | cds_list_for_each_entry(probe_desc, &probe_list, head) { |
| 245 | for (i = 0; i < probe_desc->nr_events; i++) { |
| 246 | const struct tracepoint_loglevel_entry *ev_ll; |
| 247 | |
| 248 | if (!(probe_desc->event_desc[i]->loglevel)) |
| 249 | continue; |
| 250 | ev_ll = *probe_desc->event_desc[i]->loglevel; |
| 251 | if (!strcmp(ev_ll->identifier, entry->name)) { |
| 252 | struct ltt_event *ev; |
| 253 | int ret; |
| 254 | |
| 255 | /* create event */ |
| 256 | ret = ltt_event_create(loglevel->chan, |
| 257 | &loglevel->event_param, NULL, |
| 258 | &ev); |
| 259 | /* |
| 260 | * TODO: report error. |
| 261 | */ |
| 262 | if (ret) |
| 263 | continue; |
| 264 | cds_list_add(&ev->loglevel_list, |
| 265 | &loglevel->events); |
| 266 | } |
| 267 | } |
| 268 | } |
| 269 | } |
| 270 | |
| 271 | /* |
| 272 | * Add the loglevel to the loglevel hash table. Must be called with |
| 273 | * ust lock held. |
| 274 | */ |
| 275 | struct session_loglevel *add_loglevel(const char *name, |
| 276 | struct ltt_channel *chan, |
| 277 | struct lttng_ust_event *event_param) |
| 278 | { |
| 279 | struct cds_hlist_head *head; |
| 280 | struct cds_hlist_node *node; |
| 281 | struct loglevel_entry *e; |
| 282 | struct session_loglevel *sl; |
| 283 | size_t name_len = strlen(name) + 1; |
| 284 | uint32_t hash = jhash(name, name_len-1, 0); |
| 285 | int found = 0; |
| 286 | |
| 287 | /* loglevel entry */ |
| 288 | head = &loglevel_table[hash & (LOGLEVEL_TABLE_SIZE - 1)]; |
| 289 | cds_hlist_for_each_entry(e, node, head, hlist) { |
| 290 | if (!strcmp(name, e->name)) { |
| 291 | found = 1; |
| 292 | break; |
| 293 | } |
| 294 | } |
| 295 | |
| 296 | if (!found) { |
| 297 | /* |
| 298 | * Using zmalloc here to allocate a variable length element. Could |
| 299 | * cause some memory fragmentation if overused. |
| 300 | */ |
| 301 | e = zmalloc(sizeof(struct loglevel_entry) + name_len); |
| 302 | if (!e) |
| 303 | return ERR_PTR(-ENOMEM); |
| 304 | memcpy(&e->name[0], name, name_len); |
| 305 | cds_hlist_add_head(&e->hlist, head); |
| 306 | } |
| 307 | |
| 308 | /* session loglevel */ |
| 309 | cds_list_for_each_entry(sl, &e->session_list, session_list) { |
| 310 | if (chan == sl->chan) { |
| 311 | DBG("loglevel %s busy for this channel", name); |
| 312 | return ERR_PTR(-EEXIST); /* Already there */ |
| 313 | } |
| 314 | } |
| 315 | sl = zmalloc(sizeof(struct session_loglevel)); |
| 316 | if (!sl) |
| 317 | return ERR_PTR(-ENOMEM); |
| 318 | sl->chan = chan; |
| 319 | sl->enabled = 1; |
| 320 | memcpy(&sl->event_param, event_param, sizeof(sl->event_param)); |
| 321 | CDS_INIT_LIST_HEAD(&sl->events); |
| 322 | cds_list_add(&sl->list, &chan->session->loglevels); |
| 323 | cds_list_add(&sl->session_list, &e->session_list); |
| 324 | _probes_create_loglevel_events(e, sl); |
| 325 | return sl; |
| 326 | } |
| 327 | |
| 328 | /* |
| 329 | * Remove the loglevel from the loglevel hash table. Must be called with |
| 330 | * ust_lock held. Only called at session teardown. |
| 331 | */ |
| 332 | void _remove_loglevel(struct session_loglevel *loglevel) |
| 333 | { |
| 334 | struct ltt_event *ev, *tmp; |
| 335 | |
| 336 | /* |
| 337 | * Just remove the events owned (for enable/disable) by this |
| 338 | * loglevel from the list. The session teardown will take care |
| 339 | * of freeing the event memory. |
| 340 | */ |
| 341 | cds_list_for_each_entry_safe(ev, tmp, &loglevel->events, list) { |
| 342 | cds_list_del(&ev->list); |
| 343 | } |
| 344 | cds_list_del(&loglevel->session_list); |
| 345 | cds_list_del(&loglevel->list); |
| 346 | if (cds_list_empty(&loglevel->entry->session_list)) { |
| 347 | cds_hlist_del(&loglevel->entry->hlist); |
| 348 | free(loglevel->entry); |
| 349 | } |
| 350 | free(loglevel); |
| 351 | } |
| 352 | |
| 353 | int ltt_loglevel_enable(struct session_loglevel *loglevel) |
| 354 | { |
| 355 | struct ltt_event *ev; |
| 356 | int ret; |
| 357 | |
| 358 | if (loglevel->enabled) |
| 359 | return -EEXIST; |
| 360 | cds_list_for_each_entry(ev, &loglevel->events, list) { |
| 361 | ret = ltt_event_enable(ev); |
| 362 | if (ret) { |
| 363 | DBG("Error: enable error.\n"); |
| 364 | return ret; |
| 365 | } |
| 366 | } |
| 367 | loglevel->enabled = 1; |
| 368 | return 0; |
| 369 | } |
| 370 | |
| 371 | int ltt_loglevel_disable(struct session_loglevel *loglevel) |
| 372 | { |
| 373 | struct ltt_event *ev; |
| 374 | int ret; |
| 375 | |
| 376 | if (!loglevel->enabled) |
| 377 | return -EEXIST; |
| 378 | cds_list_for_each_entry(ev, &loglevel->events, list) { |
| 379 | ret = ltt_event_disable(ev); |
| 380 | if (ret) { |
| 381 | DBG("Error: disable error.\n"); |
| 382 | return ret; |
| 383 | } |
| 384 | } |
| 385 | loglevel->enabled = 0; |
| 386 | return 0; |
| 387 | } |