X-Git-Url: http://git.liburcu.org/?a=blobdiff_plain;f=liblttng-ust%2Flttng-probes.c;h=390265add0d22feb4936ac09962aa05a9c342434;hb=c362addf1c50e1d3202a26ff96738b71b4f9a531;hp=6b671da06c673ad0f6c59622062038439b46f138;hpb=48205d6057735bebb9e9fb87781bb17614782200;p=lttng-ust.git diff --git a/liblttng-ust/lttng-probes.c b/liblttng-ust/lttng-probes.c index 6b671da0..390265ad 100644 --- a/liblttng-ust/lttng-probes.c +++ b/liblttng-ust/lttng-probes.c @@ -20,6 +20,7 @@ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */ +#define _LGPL_SOURCE #include #include #include @@ -38,25 +39,23 @@ /* * probe list is protected by ust_lock()/ust_unlock(). */ -CDS_LIST_HEAD(probe_list); +static CDS_LIST_HEAD(_probe_list); -struct cds_list_head *lttng_get_probe_list_head(void) -{ - return &probe_list; -} - -static -const struct lttng_probe_desc *find_provider(const char *provider) -{ - struct lttng_probe_desc *iter; +/* + * List of probes registered by not yet processed. + */ +static CDS_LIST_HEAD(lazy_probe_init); - cds_list_for_each_entry(iter, &probe_list, head) { - if (!strcmp(iter->provider, provider)) - return iter; - } - return NULL; -} +/* + * lazy_nesting counter ensures we don't trigger lazy probe registration + * fixup while we are performing the fixup. It is protected by the ust + * mutex. + */ +static int lazy_nesting; +/* + * Called under ust lock. + */ static int check_event_provider(struct lttng_probe_desc *desc) { @@ -74,21 +73,14 @@ int check_event_provider(struct lttng_probe_desc *desc) return 1; } -int lttng_probe_register(struct lttng_probe_desc *desc) +/* + * Called under ust lock. + */ +static +void lttng_lazy_probe_register(struct lttng_probe_desc *desc) { struct lttng_probe_desc *iter; - int ret = 0; - int i; - - ust_lock(); - - /* - * Check if the provider has already been registered. - */ - if (find_provider(desc->provider)) { - ret = -EEXIST; - goto end; - } + struct cds_list_head *probe_list; /* * Each provider enforce that every event name begins with the @@ -108,7 +100,8 @@ int lttng_probe_register(struct lttng_probe_desc *desc) * We sort the providers by struct lttng_probe_desc pointer * address. */ - cds_list_for_each_entry_reverse(iter, &probe_list, head) { + probe_list = &_probe_list; + cds_list_for_each_entry_reverse(iter, probe_list, head) { BUG_ON(iter == desc); /* Should never be in the list twice */ if (iter < desc) { /* We belong to the location right after iter. */ @@ -117,22 +110,120 @@ int lttng_probe_register(struct lttng_probe_desc *desc) } } /* We should be added at the head of the list */ - cds_list_add(&desc->head, &probe_list); + cds_list_add(&desc->head, probe_list); desc_added: DBG("just registered probe %s containing %u events", desc->provider, desc->nr_events); +} + +/* + * Called under ust lock. + */ +static +void fixup_lazy_probes(void) +{ + struct lttng_probe_desc *iter, *tmp; + int ret; + + lazy_nesting++; + cds_list_for_each_entry_safe(iter, tmp, + &lazy_probe_init, lazy_init_head) { + lttng_lazy_probe_register(iter); + iter->lazy = 0; + cds_list_del(&iter->lazy_init_head); + } + ret = lttng_fix_pending_events(); + assert(!ret); + lazy_nesting--; +} + +/* + * Called under ust lock. + */ +struct cds_list_head *lttng_get_probe_list_head(void) +{ + if (!lazy_nesting && !cds_list_empty(&lazy_probe_init)) + fixup_lazy_probes(); + return &_probe_list; +} + +static +const struct lttng_probe_desc *find_provider(const char *provider) +{ + struct lttng_probe_desc *iter; + struct cds_list_head *probe_list; + + probe_list = lttng_get_probe_list_head(); + cds_list_for_each_entry(iter, probe_list, head) { + if (!strcmp(iter->provider, provider)) + return iter; + } + return NULL; +} + +static +int check_provider_version(struct lttng_probe_desc *desc) +{ /* - * fix the events awaiting probe load. + * Check tracepoint provider version compatibility. */ - for (i = 0; i < desc->nr_events; i++) { - const struct lttng_event_desc *ed; + if (desc->major <= LTTNG_UST_PROVIDER_MAJOR) { + DBG("Provider \"%s\" accepted, version %u.%u is compatible " + "with LTTng UST provider version %u.%u.", + desc->provider, desc->major, desc->minor, + LTTNG_UST_PROVIDER_MAJOR, + LTTNG_UST_PROVIDER_MINOR); + if (desc->major < LTTNG_UST_PROVIDER_MAJOR) { + DBG("However, some LTTng UST features might not be " + "available for this provider unless it is " + "recompiled against a more recent LTTng UST."); + } + return 1; /* accept */ + } else { + ERR("Provider \"%s\" rejected, version %u.%u is incompatible " + "with LTTng UST provider version %u.%u. Please upgrade " + "LTTng UST.", + desc->provider, desc->major, desc->minor, + LTTNG_UST_PROVIDER_MAJOR, + LTTNG_UST_PROVIDER_MINOR); + return 0; /* reject */ + } +} - ed = desc->event_desc[i]; - DBG("Registered event probe \"%s\" with signature \"%s\"", - ed->name, ed->signature); - ret = lttng_fix_pending_event_desc(ed); - assert(!ret); + +int lttng_probe_register(struct lttng_probe_desc *desc) +{ + int ret = 0; + + lttng_ust_fixup_tls(); + + /* + * If version mismatch, don't register, but don't trigger assert + * on caller. The version check just prints an error. + */ + if (!check_provider_version(desc)) + return 0; + + ust_lock_nocheck(); + + /* + * Check if the provider has already been registered. + */ + if (find_provider(desc->provider)) { + ret = -EEXIST; + goto end; } + cds_list_add(&desc->lazy_init_head, &lazy_probe_init); + desc->lazy = 1; + DBG("adding probe %s containing %u events to lazy registration list", + desc->provider, desc->nr_events); + /* + * If there is at least one active session, we need to register + * the probe immediately, since we cannot delay event + * registration because they are needed ASAP. + */ + if (lttng_session_active()) + fixup_lazy_probes(); end: ust_unlock(); return ret; @@ -146,8 +237,16 @@ int ltt_probe_register(struct lttng_probe_desc *desc) void lttng_probe_unregister(struct lttng_probe_desc *desc) { - ust_lock(); - cds_list_del(&desc->head); + lttng_ust_fixup_tls(); + + if (!check_provider_version(desc)) + return; + + ust_lock_nocheck(); + if (!desc->lazy) + cds_list_del(&desc->head); + else + cds_list_del(&desc->lazy_init_head); DBG("just unregistered probe %s", desc->provider); ust_unlock(); } @@ -175,9 +274,11 @@ int lttng_probes_get_event_list(struct lttng_ust_tracepoint_list *list) { struct lttng_probe_desc *probe_desc; int i; + struct cds_list_head *probe_list; + probe_list = lttng_get_probe_list_head(); CDS_INIT_LIST_HEAD(&list->head); - cds_list_for_each_entry(probe_desc, &probe_list, head) { + cds_list_for_each_entry(probe_desc, probe_list, head) { for (i = 0; i < probe_desc->nr_events; i++) { struct tp_list_entry *list_entry; @@ -245,9 +346,11 @@ int lttng_probes_get_field_list(struct lttng_ust_field_list *list) { struct lttng_probe_desc *probe_desc; int i; + struct cds_list_head *probe_list; + probe_list = lttng_get_probe_list_head(); CDS_INIT_LIST_HEAD(&list->head); - cds_list_for_each_entry(probe_desc, &probe_list, head) { + cds_list_for_each_entry(probe_desc, probe_list, head) { for (i = 0; i < probe_desc->nr_events; i++) { const struct lttng_event_desc *event_desc = probe_desc->event_desc[i];