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53569322 | 1 | /* |
c0c0989a | 2 | * SPDX-License-Identifier: LGPL-2.1-only |
53569322 MD |
3 | * |
4 | * Copyright (C) 2016 Mathieu Desnoyers <mathieu.desnoyers@efficios.com> | |
5 | * | |
c0c0989a | 6 | * LTTng UST application context provider. |
53569322 MD |
7 | */ |
8 | ||
3fbec7dc | 9 | #define _LGPL_SOURCE |
b4051ad8 | 10 | #include <stddef.h> |
fb31eb73 | 11 | #include <stdint.h> |
53569322 MD |
12 | #include <sys/types.h> |
13 | #include <unistd.h> | |
fb31eb73 | 14 | |
9d315d6d | 15 | #include <common/ust-context-provider.h> |
d8d2416d | 16 | |
fc80554e | 17 | #include "context-internal.h" |
53569322 | 18 | #include "lttng-tracer-core.h" |
e58e5ad5 | 19 | #include "common/jhash.h" |
d8d2416d | 20 | #include "context-provider-internal.h" |
9d315d6d | 21 | #include "common/macros.h" |
8cd08025 | 22 | #include "common/tracer.h" |
53569322 | 23 | |
4e48b5d2 MD |
24 | struct lttng_ust_registered_context_provider { |
25 | const struct lttng_ust_context_provider *provider; | |
26 | ||
27 | struct cds_hlist_node node; | |
28 | }; | |
29 | ||
53569322 MD |
30 | #define CONTEXT_PROVIDER_HT_BITS 12 |
31 | #define CONTEXT_PROVIDER_HT_SIZE (1U << CONTEXT_PROVIDER_HT_BITS) | |
32 | struct context_provider_ht { | |
33 | struct cds_hlist_head table[CONTEXT_PROVIDER_HT_SIZE]; | |
34 | }; | |
35 | ||
36 | static struct context_provider_ht context_provider_ht; | |
37 | ||
4e48b5d2 | 38 | static const struct lttng_ust_context_provider * |
53569322 MD |
39 | lookup_provider_by_name(const char *name) |
40 | { | |
41 | struct cds_hlist_head *head; | |
42 | struct cds_hlist_node *node; | |
4e48b5d2 | 43 | struct lttng_ust_registered_context_provider *reg_provider; |
53569322 MD |
44 | uint32_t hash; |
45 | const char *end; | |
46 | size_t len; | |
47 | ||
48 | /* Lookup using everything before first ':' as key. */ | |
49 | end = strchr(name, ':'); | |
50 | if (end) | |
51 | len = end - name; | |
52 | else | |
53 | len = strlen(name); | |
54 | hash = jhash(name, len, 0); | |
55 | head = &context_provider_ht.table[hash & (CONTEXT_PROVIDER_HT_SIZE - 1)]; | |
4e48b5d2 MD |
56 | cds_hlist_for_each_entry(reg_provider, node, head, node) { |
57 | if (!strncmp(reg_provider->provider->name, name, len)) | |
58 | return reg_provider->provider; | |
53569322 MD |
59 | } |
60 | return NULL; | |
61 | } | |
62 | ||
4e48b5d2 | 63 | struct lttng_ust_registered_context_provider *lttng_ust_context_provider_register(struct lttng_ust_context_provider *provider) |
53569322 | 64 | { |
4e48b5d2 | 65 | struct lttng_ust_registered_context_provider *reg_provider = NULL; |
53569322 MD |
66 | struct cds_hlist_head *head; |
67 | size_t name_len = strlen(provider->name); | |
68 | uint32_t hash; | |
53569322 | 69 | |
a9fd951a | 70 | lttng_ust_alloc_tls(); |
c362addf | 71 | |
53569322 | 72 | /* Provider name starts with "$app.". */ |
fe94775b | 73 | if (strncmp("$app.", provider->name, strlen("$app.")) != 0) |
4e48b5d2 | 74 | return NULL; |
8b05d0d4 | 75 | /* Provider name cannot contain a colon character. */ |
53569322 | 76 | if (strchr(provider->name, ':')) |
4e48b5d2 MD |
77 | return NULL; |
78 | if (ust_lock()) | |
53569322 | 79 | goto end; |
4e48b5d2 | 80 | if (lookup_provider_by_name(provider->name)) |
53569322 | 81 | goto end; |
4e48b5d2 MD |
82 | reg_provider = zmalloc(sizeof(struct lttng_ust_registered_context_provider)); |
83 | if (!reg_provider) | |
84 | goto end; | |
85 | reg_provider->provider = provider; | |
53569322 MD |
86 | hash = jhash(provider->name, name_len, 0); |
87 | head = &context_provider_ht.table[hash & (CONTEXT_PROVIDER_HT_SIZE - 1)]; | |
4e48b5d2 | 88 | cds_hlist_add_head(®_provider->node, head); |
d8d2416d | 89 | |
53569322 MD |
90 | lttng_ust_context_set_session_provider(provider->name, |
91 | provider->get_size, provider->record, | |
4e48b5d2 | 92 | provider->get_value, provider->priv); |
d8d2416d FD |
93 | |
94 | lttng_ust_context_set_event_notifier_group_provider(provider->name, | |
95 | provider->get_size, provider->record, | |
4e48b5d2 | 96 | provider->get_value, provider->priv); |
53569322 MD |
97 | end: |
98 | ust_unlock(); | |
4e48b5d2 | 99 | return reg_provider; |
53569322 MD |
100 | } |
101 | ||
4e48b5d2 | 102 | void lttng_ust_context_provider_unregister(struct lttng_ust_registered_context_provider *reg_provider) |
53569322 | 103 | { |
a9fd951a | 104 | lttng_ust_alloc_tls(); |
c362addf | 105 | |
53569322 MD |
106 | if (ust_lock()) |
107 | goto end; | |
4e48b5d2 | 108 | lttng_ust_context_set_session_provider(reg_provider->provider->name, |
ce7352a2 | 109 | lttng_ust_dummy_get_size, lttng_ust_dummy_record, |
4e48b5d2 | 110 | lttng_ust_dummy_get_value, NULL); |
d8d2416d | 111 | |
4e48b5d2 | 112 | lttng_ust_context_set_event_notifier_group_provider(reg_provider->provider->name, |
d8d2416d | 113 | lttng_ust_dummy_get_size, lttng_ust_dummy_record, |
4e48b5d2 | 114 | lttng_ust_dummy_get_value, NULL); |
d8d2416d | 115 | |
4e48b5d2 | 116 | cds_hlist_del(®_provider->node); |
53569322 MD |
117 | end: |
118 | ust_unlock(); | |
4e48b5d2 | 119 | free(reg_provider); |
53569322 MD |
120 | } |
121 | ||
122 | /* | |
123 | * Called with ust mutex held. | |
124 | * Add application context to array of context, even if the application | |
125 | * context is not currently loaded by application. It will then use the | |
126 | * dummy callbacks in that case. | |
127 | * Always performed before tracing is started, since it modifies | |
128 | * metadata describing the context. | |
129 | */ | |
130 | int lttng_ust_add_app_context_to_ctx_rcu(const char *name, | |
daacdbfc | 131 | struct lttng_ust_ctx **ctx) |
53569322 | 132 | { |
4e48b5d2 | 133 | const struct lttng_ust_context_provider *provider; |
f26f2f9b | 134 | struct lttng_ust_ctx_field new_field = { 0 }; |
4e48b5d2 MD |
135 | struct lttng_ust_event_field *event_field = NULL; |
136 | struct lttng_ust_type_common *type = NULL; | |
f26f2f9b | 137 | char *ctx_name; |
53569322 MD |
138 | int ret; |
139 | ||
140 | if (*ctx && lttng_find_context(*ctx, name)) | |
141 | return -EEXIST; | |
4e48b5d2 MD |
142 | event_field = zmalloc(sizeof(struct lttng_ust_event_field)); |
143 | if (!event_field) { | |
daacdbfc MD |
144 | ret = -ENOMEM; |
145 | goto error_event_field_alloc; | |
146 | } | |
f26f2f9b MD |
147 | ctx_name = strdup(name); |
148 | if (!ctx_name) { | |
daacdbfc MD |
149 | ret = -ENOMEM; |
150 | goto error_field_name_alloc; | |
151 | } | |
4e48b5d2 MD |
152 | type = zmalloc(sizeof(struct lttng_ust_type_common)); |
153 | if (!type) { | |
a084756d MD |
154 | ret = -ENOMEM; |
155 | goto error_field_type_alloc; | |
156 | } | |
f26f2f9b | 157 | event_field->name = ctx_name; |
4e48b5d2 MD |
158 | type->type = lttng_ust_type_dynamic; |
159 | event_field->type = type; | |
f26f2f9b | 160 | new_field.event_field = event_field; |
53569322 MD |
161 | /* |
162 | * If provider is not found, we add the context anyway, but | |
163 | * it will provide a dummy context. | |
164 | */ | |
165 | provider = lookup_provider_by_name(name); | |
166 | if (provider) { | |
f26f2f9b MD |
167 | new_field.get_size = provider->get_size; |
168 | new_field.record = provider->record; | |
169 | new_field.get_value = provider->get_value; | |
d6f956db | 170 | new_field.priv = provider->priv; |
53569322 | 171 | } else { |
f26f2f9b MD |
172 | new_field.get_size = lttng_ust_dummy_get_size; |
173 | new_field.record = lttng_ust_dummy_record; | |
174 | new_field.get_value = lttng_ust_dummy_get_value; | |
d6f956db | 175 | new_field.priv = NULL; |
53569322 | 176 | } |
daacdbfc MD |
177 | /* |
178 | * For application context, add it by expanding | |
f26f2f9b | 179 | * ctx array. |
daacdbfc | 180 | */ |
f26f2f9b | 181 | ret = lttng_ust_context_append_rcu(ctx, &new_field); |
53569322 | 182 | if (ret) { |
d6f956db | 183 | goto error_append; |
53569322 MD |
184 | } |
185 | return 0; | |
daacdbfc | 186 | |
d6f956db | 187 | error_append: |
f26f2f9b | 188 | free(type); |
a084756d | 189 | error_field_type_alloc: |
f26f2f9b | 190 | free(ctx_name); |
daacdbfc | 191 | error_field_name_alloc: |
4e48b5d2 | 192 | free(event_field); |
daacdbfc | 193 | error_event_field_alloc: |
daacdbfc | 194 | return ret; |
53569322 | 195 | } |