| 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 <lttng/ust-events.h> |
| 15 | #include <assert.h> |
| 16 | |
| 17 | #include "ltt-tracer-core.h" |
| 18 | |
| 19 | /* |
| 20 | * probe list is protected by ust_lock()/ust_unlock(). |
| 21 | */ |
| 22 | static CDS_LIST_HEAD(probe_list); |
| 23 | |
| 24 | static |
| 25 | const struct lttng_probe_desc *find_provider(const char *provider) |
| 26 | { |
| 27 | struct lttng_probe_desc *iter; |
| 28 | |
| 29 | cds_list_for_each_entry(iter, &probe_list, head) { |
| 30 | if (!strcmp(iter->provider, provider)) |
| 31 | return iter; |
| 32 | } |
| 33 | return NULL; |
| 34 | } |
| 35 | |
| 36 | static |
| 37 | const struct lttng_event_desc *find_event(const char *name) |
| 38 | { |
| 39 | struct lttng_probe_desc *probe_desc; |
| 40 | int i; |
| 41 | |
| 42 | cds_list_for_each_entry(probe_desc, &probe_list, head) { |
| 43 | for (i = 0; i < probe_desc->nr_events; i++) { |
| 44 | if (!strcmp(probe_desc->event_desc[i]->name, name)) |
| 45 | return probe_desc->event_desc[i]; |
| 46 | } |
| 47 | } |
| 48 | return NULL; |
| 49 | } |
| 50 | |
| 51 | int ltt_probe_register(struct lttng_probe_desc *desc) |
| 52 | { |
| 53 | struct lttng_probe_desc *iter; |
| 54 | int ret = 0; |
| 55 | int i; |
| 56 | |
| 57 | ust_lock(); |
| 58 | if (find_provider(desc->provider)) { |
| 59 | ret = -EEXIST; |
| 60 | goto end; |
| 61 | } |
| 62 | /* |
| 63 | * TODO: This is O(N^2). Turn into a hash table when probe registration |
| 64 | * overhead becomes an issue. |
| 65 | */ |
| 66 | for (i = 0; i < desc->nr_events; i++) { |
| 67 | if (find_event(desc->event_desc[i]->name)) { |
| 68 | ret = -EEXIST; |
| 69 | goto end; |
| 70 | } |
| 71 | } |
| 72 | |
| 73 | /* |
| 74 | * We sort the providers by struct lttng_probe_desc pointer |
| 75 | * address. |
| 76 | */ |
| 77 | cds_list_for_each_entry_reverse(iter, &probe_list, head) { |
| 78 | BUG_ON(iter == desc); /* Should never be in the list twice */ |
| 79 | if (iter < desc) { |
| 80 | /* We belong to the location right after iter. */ |
| 81 | cds_list_add(&desc->head, &iter->head); |
| 82 | goto desc_added; |
| 83 | } |
| 84 | } |
| 85 | /* We should be added at the head of the list */ |
| 86 | cds_list_add(&desc->head, &probe_list); |
| 87 | desc_added: |
| 88 | |
| 89 | /* |
| 90 | * fix the events awaiting probe load. |
| 91 | */ |
| 92 | for (i = 0; i < desc->nr_events; i++) { |
| 93 | ret = pending_probe_fix_events(desc->event_desc[i]); |
| 94 | assert(!ret); |
| 95 | } |
| 96 | end: |
| 97 | ust_unlock(); |
| 98 | return ret; |
| 99 | } |
| 100 | |
| 101 | void ltt_probe_unregister(struct lttng_probe_desc *desc) |
| 102 | { |
| 103 | ust_lock(); |
| 104 | cds_list_del(&desc->head); |
| 105 | ust_unlock(); |
| 106 | } |
| 107 | |
| 108 | /* |
| 109 | * called with UST lock held. |
| 110 | */ |
| 111 | const struct lttng_event_desc *ltt_event_get(const char *name) |
| 112 | { |
| 113 | const struct lttng_event_desc *event; |
| 114 | |
| 115 | event = find_event(name); |
| 116 | if (!event) |
| 117 | return NULL; |
| 118 | return event; |
| 119 | } |
| 120 | |
| 121 | void ltt_event_put(const struct lttng_event_desc *event) |
| 122 | { |
| 123 | } |