| 1 | /* |
| 2 | * lttng-context.c |
| 3 | * |
| 4 | * LTTng UST trace/channel/event context management. |
| 5 | * |
| 6 | * Copyright (C) 2011 Mathieu Desnoyers <mathieu.desnoyers@efficios.com> |
| 7 | * |
| 8 | * This library is free software; you can redistribute it and/or |
| 9 | * modify it under the terms of the GNU Lesser General Public |
| 10 | * License as published by the Free Software Foundation; only |
| 11 | * version 2.1 of the License. |
| 12 | * |
| 13 | * This library is distributed in the hope that it will be useful, |
| 14 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 15 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| 16 | * Lesser General Public License for more details. |
| 17 | * |
| 18 | * You should have received a copy of the GNU Lesser General Public |
| 19 | * License along with this library; if not, write to the Free Software |
| 20 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
| 21 | */ |
| 22 | |
| 23 | |
| 24 | #include <lttng/ust-events.h> |
| 25 | #include <lttng/ust-tracer.h> |
| 26 | #include <usterr-signal-safe.h> |
| 27 | #include <helper.h> |
| 28 | #include <string.h> |
| 29 | #include <assert.h> |
| 30 | |
| 31 | /* |
| 32 | * The filter implementation requires that two consecutive "get" for the |
| 33 | * same context performed by the same thread return the same result. |
| 34 | */ |
| 35 | |
| 36 | /* |
| 37 | * Static array of contexts, for $ctx filters. |
| 38 | */ |
| 39 | struct lttng_ctx *lttng_static_ctx; |
| 40 | |
| 41 | int lttng_find_context(struct lttng_ctx *ctx, const char *name) |
| 42 | { |
| 43 | unsigned int i; |
| 44 | |
| 45 | for (i = 0; i < ctx->nr_fields; i++) { |
| 46 | /* Skip allocated (but non-initialized) contexts */ |
| 47 | if (!ctx->fields[i].event_field.name) |
| 48 | continue; |
| 49 | if (!strcmp(ctx->fields[i].event_field.name, name)) |
| 50 | return 1; |
| 51 | } |
| 52 | return 0; |
| 53 | } |
| 54 | |
| 55 | int lttng_get_context_index(struct lttng_ctx *ctx, const char *name) |
| 56 | { |
| 57 | unsigned int i; |
| 58 | |
| 59 | if (!ctx) |
| 60 | return -1; |
| 61 | for (i = 0; i < ctx->nr_fields; i++) { |
| 62 | /* Skip allocated (but non-initialized) contexts */ |
| 63 | if (!ctx->fields[i].event_field.name) |
| 64 | continue; |
| 65 | if (!strcmp(ctx->fields[i].event_field.name, name)) |
| 66 | return i; |
| 67 | } |
| 68 | return -1; |
| 69 | } |
| 70 | |
| 71 | /* |
| 72 | * Note: as we append context information, the pointer location may change. |
| 73 | */ |
| 74 | struct lttng_ctx_field *lttng_append_context(struct lttng_ctx **ctx_p) |
| 75 | { |
| 76 | struct lttng_ctx_field *field; |
| 77 | struct lttng_ctx *ctx; |
| 78 | |
| 79 | if (!*ctx_p) { |
| 80 | *ctx_p = zmalloc(sizeof(struct lttng_ctx)); |
| 81 | if (!*ctx_p) |
| 82 | return NULL; |
| 83 | (*ctx_p)->largest_align = 1; |
| 84 | } |
| 85 | ctx = *ctx_p; |
| 86 | if (ctx->nr_fields + 1 > ctx->allocated_fields) { |
| 87 | struct lttng_ctx_field *new_fields; |
| 88 | |
| 89 | ctx->allocated_fields = max_t(size_t, 1, 2 * ctx->allocated_fields); |
| 90 | new_fields = zmalloc(ctx->allocated_fields * sizeof(struct lttng_ctx_field)); |
| 91 | if (!new_fields) |
| 92 | return NULL; |
| 93 | if (ctx->fields) |
| 94 | memcpy(new_fields, ctx->fields, sizeof(*ctx->fields) * ctx->nr_fields); |
| 95 | free(ctx->fields); |
| 96 | ctx->fields = new_fields; |
| 97 | } |
| 98 | field = &ctx->fields[ctx->nr_fields]; |
| 99 | ctx->nr_fields++; |
| 100 | return field; |
| 101 | } |
| 102 | |
| 103 | /* |
| 104 | * lttng_context_update() should be called at least once between context |
| 105 | * modification and trace start. |
| 106 | */ |
| 107 | void lttng_context_update(struct lttng_ctx *ctx) |
| 108 | { |
| 109 | int i; |
| 110 | size_t largest_align = 8; /* in bits */ |
| 111 | |
| 112 | for (i = 0; i < ctx->nr_fields; i++) { |
| 113 | struct lttng_type *type; |
| 114 | size_t field_align = 8; |
| 115 | |
| 116 | type = &ctx->fields[i].event_field.type; |
| 117 | switch (type->atype) { |
| 118 | case atype_integer: |
| 119 | field_align = type->u.basic.integer.alignment; |
| 120 | break; |
| 121 | case atype_array: |
| 122 | { |
| 123 | struct lttng_basic_type *btype; |
| 124 | |
| 125 | btype = &type->u.array.elem_type; |
| 126 | switch (btype->atype) { |
| 127 | case atype_integer: |
| 128 | field_align = btype->u.basic.integer.alignment; |
| 129 | break; |
| 130 | case atype_string: |
| 131 | break; |
| 132 | |
| 133 | case atype_array: |
| 134 | case atype_sequence: |
| 135 | default: |
| 136 | WARN_ON_ONCE(1); |
| 137 | break; |
| 138 | } |
| 139 | break; |
| 140 | } |
| 141 | case atype_sequence: |
| 142 | { |
| 143 | struct lttng_basic_type *btype; |
| 144 | |
| 145 | btype = &type->u.sequence.length_type; |
| 146 | switch (btype->atype) { |
| 147 | case atype_integer: |
| 148 | field_align = btype->u.basic.integer.alignment; |
| 149 | break; |
| 150 | |
| 151 | case atype_string: |
| 152 | case atype_array: |
| 153 | case atype_sequence: |
| 154 | default: |
| 155 | WARN_ON_ONCE(1); |
| 156 | break; |
| 157 | } |
| 158 | |
| 159 | btype = &type->u.sequence.elem_type; |
| 160 | switch (btype->atype) { |
| 161 | case atype_integer: |
| 162 | field_align = max_t(size_t, |
| 163 | field_align, |
| 164 | btype->u.basic.integer.alignment); |
| 165 | break; |
| 166 | |
| 167 | case atype_string: |
| 168 | break; |
| 169 | |
| 170 | case atype_array: |
| 171 | case atype_sequence: |
| 172 | default: |
| 173 | WARN_ON_ONCE(1); |
| 174 | break; |
| 175 | } |
| 176 | break; |
| 177 | } |
| 178 | case atype_string: |
| 179 | break; |
| 180 | |
| 181 | case atype_enum: |
| 182 | default: |
| 183 | WARN_ON_ONCE(1); |
| 184 | break; |
| 185 | } |
| 186 | largest_align = max_t(size_t, largest_align, field_align); |
| 187 | } |
| 188 | ctx->largest_align = largest_align >> 3; /* bits to bytes */ |
| 189 | } |
| 190 | |
| 191 | /* |
| 192 | * Remove last context field. |
| 193 | */ |
| 194 | void lttng_remove_context_field(struct lttng_ctx **ctx_p, |
| 195 | struct lttng_ctx_field *field) |
| 196 | { |
| 197 | struct lttng_ctx *ctx; |
| 198 | |
| 199 | ctx = *ctx_p; |
| 200 | ctx->nr_fields--; |
| 201 | assert(&ctx->fields[ctx->nr_fields] == field); |
| 202 | memset(&ctx->fields[ctx->nr_fields], 0, sizeof(struct lttng_ctx_field)); |
| 203 | } |
| 204 | |
| 205 | void lttng_destroy_context(struct lttng_ctx *ctx) |
| 206 | { |
| 207 | int i; |
| 208 | |
| 209 | if (!ctx) |
| 210 | return; |
| 211 | for (i = 0; i < ctx->nr_fields; i++) { |
| 212 | if (ctx->fields[i].destroy) |
| 213 | ctx->fields[i].destroy(&ctx->fields[i]); |
| 214 | } |
| 215 | free(ctx->fields); |
| 216 | free(ctx); |
| 217 | } |
| 218 | |
| 219 | void lttng_context_init(void) |
| 220 | { |
| 221 | int ret; |
| 222 | |
| 223 | ret = lttng_add_pthread_id_to_ctx(<tng_static_ctx); |
| 224 | if (ret) { |
| 225 | WARN("Cannot add context lttng_add_pthread_id_to_ctx"); |
| 226 | } |
| 227 | ret = lttng_add_vtid_to_ctx(<tng_static_ctx); |
| 228 | if (ret) { |
| 229 | WARN("Cannot add context lttng_add_vtid_to_ctx"); |
| 230 | } |
| 231 | ret = lttng_add_vpid_to_ctx(<tng_static_ctx); |
| 232 | if (ret) { |
| 233 | WARN("Cannot add context lttng_add_vpid_to_ctx"); |
| 234 | } |
| 235 | ret = lttng_add_procname_to_ctx(<tng_static_ctx); |
| 236 | if (ret) { |
| 237 | WARN("Cannot add context lttng_add_procname_to_ctx"); |
| 238 | } |
| 239 | } |
| 240 | |
| 241 | void lttng_context_exit(void) |
| 242 | { |
| 243 | lttng_destroy_context(lttng_static_ctx); |
| 244 | lttng_static_ctx = NULL; |
| 245 | } |