| 1 | /* |
| 2 | * lttng-filter.c |
| 3 | * |
| 4 | * LTTng modules filter code. |
| 5 | * |
| 6 | * Copyright (C) 2010-2014 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 | #include <linux/list.h> |
| 24 | #include <linux/slab.h> |
| 25 | |
| 26 | #include "lttng-filter.h" |
| 27 | |
| 28 | static const char *opnames[] = { |
| 29 | [ FILTER_OP_UNKNOWN ] = "UNKNOWN", |
| 30 | |
| 31 | [ FILTER_OP_RETURN ] = "RETURN", |
| 32 | |
| 33 | /* binary */ |
| 34 | [ FILTER_OP_MUL ] = "MUL", |
| 35 | [ FILTER_OP_DIV ] = "DIV", |
| 36 | [ FILTER_OP_MOD ] = "MOD", |
| 37 | [ FILTER_OP_PLUS ] = "PLUS", |
| 38 | [ FILTER_OP_MINUS ] = "MINUS", |
| 39 | [ FILTER_OP_RSHIFT ] = "RSHIFT", |
| 40 | [ FILTER_OP_LSHIFT ] = "LSHIFT", |
| 41 | [ FILTER_OP_BIN_AND ] = "BIN_AND", |
| 42 | [ FILTER_OP_BIN_OR ] = "BIN_OR", |
| 43 | [ FILTER_OP_BIN_XOR ] = "BIN_XOR", |
| 44 | |
| 45 | /* binary comparators */ |
| 46 | [ FILTER_OP_EQ ] = "EQ", |
| 47 | [ FILTER_OP_NE ] = "NE", |
| 48 | [ FILTER_OP_GT ] = "GT", |
| 49 | [ FILTER_OP_LT ] = "LT", |
| 50 | [ FILTER_OP_GE ] = "GE", |
| 51 | [ FILTER_OP_LE ] = "LE", |
| 52 | |
| 53 | /* string binary comparators */ |
| 54 | [ FILTER_OP_EQ_STRING ] = "EQ_STRING", |
| 55 | [ FILTER_OP_NE_STRING ] = "NE_STRING", |
| 56 | [ FILTER_OP_GT_STRING ] = "GT_STRING", |
| 57 | [ FILTER_OP_LT_STRING ] = "LT_STRING", |
| 58 | [ FILTER_OP_GE_STRING ] = "GE_STRING", |
| 59 | [ FILTER_OP_LE_STRING ] = "LE_STRING", |
| 60 | |
| 61 | /* s64 binary comparators */ |
| 62 | [ FILTER_OP_EQ_S64 ] = "EQ_S64", |
| 63 | [ FILTER_OP_NE_S64 ] = "NE_S64", |
| 64 | [ FILTER_OP_GT_S64 ] = "GT_S64", |
| 65 | [ FILTER_OP_LT_S64 ] = "LT_S64", |
| 66 | [ FILTER_OP_GE_S64 ] = "GE_S64", |
| 67 | [ FILTER_OP_LE_S64 ] = "LE_S64", |
| 68 | |
| 69 | /* double binary comparators */ |
| 70 | [ FILTER_OP_EQ_DOUBLE ] = "EQ_DOUBLE", |
| 71 | [ FILTER_OP_NE_DOUBLE ] = "NE_DOUBLE", |
| 72 | [ FILTER_OP_GT_DOUBLE ] = "GT_DOUBLE", |
| 73 | [ FILTER_OP_LT_DOUBLE ] = "LT_DOUBLE", |
| 74 | [ FILTER_OP_GE_DOUBLE ] = "GE_DOUBLE", |
| 75 | [ FILTER_OP_LE_DOUBLE ] = "LE_DOUBLE", |
| 76 | |
| 77 | /* Mixed S64-double binary comparators */ |
| 78 | [ FILTER_OP_EQ_DOUBLE_S64 ] = "EQ_DOUBLE_S64", |
| 79 | [ FILTER_OP_NE_DOUBLE_S64 ] = "NE_DOUBLE_S64", |
| 80 | [ FILTER_OP_GT_DOUBLE_S64 ] = "GT_DOUBLE_S64", |
| 81 | [ FILTER_OP_LT_DOUBLE_S64 ] = "LT_DOUBLE_S64", |
| 82 | [ FILTER_OP_GE_DOUBLE_S64 ] = "GE_DOUBLE_S64", |
| 83 | [ FILTER_OP_LE_DOUBLE_S64 ] = "LE_DOUBLE_S64", |
| 84 | |
| 85 | [ FILTER_OP_EQ_S64_DOUBLE ] = "EQ_S64_DOUBLE", |
| 86 | [ FILTER_OP_NE_S64_DOUBLE ] = "NE_S64_DOUBLE", |
| 87 | [ FILTER_OP_GT_S64_DOUBLE ] = "GT_S64_DOUBLE", |
| 88 | [ FILTER_OP_LT_S64_DOUBLE ] = "LT_S64_DOUBLE", |
| 89 | [ FILTER_OP_GE_S64_DOUBLE ] = "GE_S64_DOUBLE", |
| 90 | [ FILTER_OP_LE_S64_DOUBLE ] = "LE_S64_DOUBLE", |
| 91 | |
| 92 | /* unary */ |
| 93 | [ FILTER_OP_UNARY_PLUS ] = "UNARY_PLUS", |
| 94 | [ FILTER_OP_UNARY_MINUS ] = "UNARY_MINUS", |
| 95 | [ FILTER_OP_UNARY_NOT ] = "UNARY_NOT", |
| 96 | [ FILTER_OP_UNARY_PLUS_S64 ] = "UNARY_PLUS_S64", |
| 97 | [ FILTER_OP_UNARY_MINUS_S64 ] = "UNARY_MINUS_S64", |
| 98 | [ FILTER_OP_UNARY_NOT_S64 ] = "UNARY_NOT_S64", |
| 99 | [ FILTER_OP_UNARY_PLUS_DOUBLE ] = "UNARY_PLUS_DOUBLE", |
| 100 | [ FILTER_OP_UNARY_MINUS_DOUBLE ] = "UNARY_MINUS_DOUBLE", |
| 101 | [ FILTER_OP_UNARY_NOT_DOUBLE ] = "UNARY_NOT_DOUBLE", |
| 102 | |
| 103 | /* logical */ |
| 104 | [ FILTER_OP_AND ] = "AND", |
| 105 | [ FILTER_OP_OR ] = "OR", |
| 106 | |
| 107 | /* load field ref */ |
| 108 | [ FILTER_OP_LOAD_FIELD_REF ] = "LOAD_FIELD_REF", |
| 109 | [ FILTER_OP_LOAD_FIELD_REF_STRING ] = "LOAD_FIELD_REF_STRING", |
| 110 | [ FILTER_OP_LOAD_FIELD_REF_SEQUENCE ] = "LOAD_FIELD_REF_SEQUENCE", |
| 111 | [ FILTER_OP_LOAD_FIELD_REF_S64 ] = "LOAD_FIELD_REF_S64", |
| 112 | [ FILTER_OP_LOAD_FIELD_REF_DOUBLE ] = "LOAD_FIELD_REF_DOUBLE", |
| 113 | |
| 114 | /* load from immediate operand */ |
| 115 | [ FILTER_OP_LOAD_STRING ] = "LOAD_STRING", |
| 116 | [ FILTER_OP_LOAD_S64 ] = "LOAD_S64", |
| 117 | [ FILTER_OP_LOAD_DOUBLE ] = "LOAD_DOUBLE", |
| 118 | |
| 119 | /* cast */ |
| 120 | [ FILTER_OP_CAST_TO_S64 ] = "CAST_TO_S64", |
| 121 | [ FILTER_OP_CAST_DOUBLE_TO_S64 ] = "CAST_DOUBLE_TO_S64", |
| 122 | [ FILTER_OP_CAST_NOP ] = "CAST_NOP", |
| 123 | |
| 124 | /* get context ref */ |
| 125 | [ FILTER_OP_GET_CONTEXT_REF ] = "GET_CONTEXT_REF", |
| 126 | [ FILTER_OP_GET_CONTEXT_REF_STRING ] = "GET_CONTEXT_REF_STRING", |
| 127 | [ FILTER_OP_GET_CONTEXT_REF_S64 ] = "GET_CONTEXT_REF_S64", |
| 128 | [ FILTER_OP_GET_CONTEXT_REF_DOUBLE ] = "GET_CONTEXT_REF_DOUBLE", |
| 129 | }; |
| 130 | |
| 131 | const char *lttng_filter_print_op(enum filter_op op) |
| 132 | { |
| 133 | if (op >= NR_FILTER_OPS) |
| 134 | return "UNKNOWN"; |
| 135 | else |
| 136 | return opnames[op]; |
| 137 | } |
| 138 | |
| 139 | static |
| 140 | int apply_field_reloc(struct lttng_event *event, |
| 141 | struct bytecode_runtime *runtime, |
| 142 | uint32_t runtime_len, |
| 143 | uint32_t reloc_offset, |
| 144 | const char *field_name) |
| 145 | { |
| 146 | const struct lttng_event_desc *desc; |
| 147 | const struct lttng_event_field *fields, *field = NULL; |
| 148 | unsigned int nr_fields, i; |
| 149 | struct field_ref *field_ref; |
| 150 | struct load_op *op; |
| 151 | uint32_t field_offset = 0; |
| 152 | |
| 153 | dbg_printk("Apply field reloc: %u %s\n", reloc_offset, field_name); |
| 154 | |
| 155 | /* Lookup event by name */ |
| 156 | desc = event->desc; |
| 157 | if (!desc) |
| 158 | return -EINVAL; |
| 159 | fields = desc->fields; |
| 160 | if (!fields) |
| 161 | return -EINVAL; |
| 162 | nr_fields = desc->nr_fields; |
| 163 | for (i = 0; i < nr_fields; i++) { |
| 164 | if (!strcmp(fields[i].name, field_name)) { |
| 165 | field = &fields[i]; |
| 166 | break; |
| 167 | } |
| 168 | /* compute field offset */ |
| 169 | switch (fields[i].type.atype) { |
| 170 | case atype_integer: |
| 171 | case atype_enum: |
| 172 | field_offset += sizeof(int64_t); |
| 173 | break; |
| 174 | case atype_array: |
| 175 | case atype_sequence: |
| 176 | field_offset += sizeof(unsigned long); |
| 177 | field_offset += sizeof(void *); |
| 178 | break; |
| 179 | case atype_string: |
| 180 | field_offset += sizeof(void *); |
| 181 | break; |
| 182 | default: |
| 183 | return -EINVAL; |
| 184 | } |
| 185 | } |
| 186 | if (!field) |
| 187 | return -EINVAL; |
| 188 | |
| 189 | /* Check if field offset is too large for 16-bit offset */ |
| 190 | if (field_offset > FILTER_BYTECODE_MAX_LEN - 1) |
| 191 | return -EINVAL; |
| 192 | |
| 193 | /* set type */ |
| 194 | op = (struct load_op *) &runtime->data[reloc_offset]; |
| 195 | field_ref = (struct field_ref *) op->data; |
| 196 | switch (field->type.atype) { |
| 197 | case atype_integer: |
| 198 | case atype_enum: |
| 199 | op->op = FILTER_OP_LOAD_FIELD_REF_S64; |
| 200 | break; |
| 201 | case atype_array: |
| 202 | case atype_sequence: |
| 203 | op->op = FILTER_OP_LOAD_FIELD_REF_SEQUENCE; |
| 204 | break; |
| 205 | case atype_string: |
| 206 | op->op = FILTER_OP_LOAD_FIELD_REF_STRING; |
| 207 | break; |
| 208 | default: |
| 209 | return -EINVAL; |
| 210 | } |
| 211 | /* set offset */ |
| 212 | field_ref->offset = (uint16_t) field_offset; |
| 213 | return 0; |
| 214 | } |
| 215 | |
| 216 | static |
| 217 | int apply_context_reloc(struct lttng_event *event, |
| 218 | struct bytecode_runtime *runtime, |
| 219 | uint32_t runtime_len, |
| 220 | uint32_t reloc_offset, |
| 221 | const char *context_name) |
| 222 | { |
| 223 | struct field_ref *field_ref; |
| 224 | struct load_op *op; |
| 225 | struct lttng_ctx_field *ctx_field; |
| 226 | int idx; |
| 227 | |
| 228 | dbg_printk("Apply context reloc: %u %s\n", reloc_offset, context_name); |
| 229 | |
| 230 | /* Get context index */ |
| 231 | idx = lttng_get_context_index(lttng_static_ctx, context_name); |
| 232 | if (idx < 0) |
| 233 | return -ENOENT; |
| 234 | |
| 235 | /* Check if idx is too large for 16-bit offset */ |
| 236 | if (idx > FILTER_BYTECODE_MAX_LEN - 1) |
| 237 | return -EINVAL; |
| 238 | |
| 239 | /* Get context return type */ |
| 240 | ctx_field = <tng_static_ctx->fields[idx]; |
| 241 | op = (struct load_op *) &runtime->data[reloc_offset]; |
| 242 | field_ref = (struct field_ref *) op->data; |
| 243 | switch (ctx_field->event_field.type.atype) { |
| 244 | case atype_integer: |
| 245 | case atype_enum: |
| 246 | op->op = FILTER_OP_GET_CONTEXT_REF_S64; |
| 247 | break; |
| 248 | /* Sequence and array supported as string */ |
| 249 | case atype_string: |
| 250 | case atype_array: |
| 251 | case atype_sequence: |
| 252 | op->op = FILTER_OP_GET_CONTEXT_REF_STRING; |
| 253 | break; |
| 254 | default: |
| 255 | return -EINVAL; |
| 256 | } |
| 257 | /* set offset to context index within channel contexts */ |
| 258 | field_ref->offset = (uint16_t) idx; |
| 259 | return 0; |
| 260 | } |
| 261 | |
| 262 | static |
| 263 | int apply_reloc(struct lttng_event *event, |
| 264 | struct bytecode_runtime *runtime, |
| 265 | uint32_t runtime_len, |
| 266 | uint32_t reloc_offset, |
| 267 | const char *name) |
| 268 | { |
| 269 | struct load_op *op; |
| 270 | |
| 271 | dbg_printk("Apply reloc: %u %s\n", reloc_offset, name); |
| 272 | |
| 273 | /* Ensure that the reloc is within the code */ |
| 274 | if (runtime_len - reloc_offset < sizeof(uint16_t)) |
| 275 | return -EINVAL; |
| 276 | |
| 277 | op = (struct load_op *) &runtime->data[reloc_offset]; |
| 278 | switch (op->op) { |
| 279 | case FILTER_OP_LOAD_FIELD_REF: |
| 280 | return apply_field_reloc(event, runtime, runtime_len, |
| 281 | reloc_offset, name); |
| 282 | case FILTER_OP_GET_CONTEXT_REF: |
| 283 | return apply_context_reloc(event, runtime, runtime_len, |
| 284 | reloc_offset, name); |
| 285 | default: |
| 286 | printk(KERN_WARNING "Unknown reloc op type %u\n", op->op); |
| 287 | return -EINVAL; |
| 288 | } |
| 289 | return 0; |
| 290 | } |
| 291 | |
| 292 | static |
| 293 | int bytecode_is_linked(struct lttng_filter_bytecode_node *filter_bytecode, |
| 294 | struct lttng_event *event) |
| 295 | { |
| 296 | struct lttng_bytecode_runtime *bc_runtime; |
| 297 | |
| 298 | list_for_each_entry(bc_runtime, |
| 299 | &event->bytecode_runtime_head, node) { |
| 300 | if (bc_runtime->bc == filter_bytecode) |
| 301 | return 1; |
| 302 | } |
| 303 | return 0; |
| 304 | } |
| 305 | |
| 306 | /* |
| 307 | * Take a bytecode with reloc table and link it to an event to create a |
| 308 | * bytecode runtime. |
| 309 | */ |
| 310 | static |
| 311 | int _lttng_filter_event_link_bytecode(struct lttng_event *event, |
| 312 | struct lttng_filter_bytecode_node *filter_bytecode, |
| 313 | struct list_head *insert_loc) |
| 314 | { |
| 315 | int ret, offset, next_offset; |
| 316 | struct bytecode_runtime *runtime = NULL; |
| 317 | size_t runtime_alloc_len; |
| 318 | |
| 319 | if (!filter_bytecode) |
| 320 | return 0; |
| 321 | /* Bytecode already linked */ |
| 322 | if (bytecode_is_linked(filter_bytecode, event)) |
| 323 | return 0; |
| 324 | |
| 325 | dbg_printk("Linking...\n"); |
| 326 | |
| 327 | /* We don't need the reloc table in the runtime */ |
| 328 | runtime_alloc_len = sizeof(*runtime) + filter_bytecode->bc.reloc_offset; |
| 329 | runtime = kzalloc(runtime_alloc_len, GFP_KERNEL); |
| 330 | if (!runtime) { |
| 331 | ret = -ENOMEM; |
| 332 | goto alloc_error; |
| 333 | } |
| 334 | runtime->p.bc = filter_bytecode; |
| 335 | runtime->len = filter_bytecode->bc.reloc_offset; |
| 336 | /* copy original bytecode */ |
| 337 | memcpy(runtime->data, filter_bytecode->bc.data, runtime->len); |
| 338 | /* |
| 339 | * apply relocs. Those are a uint16_t (offset in bytecode) |
| 340 | * followed by a string (field name). |
| 341 | */ |
| 342 | for (offset = filter_bytecode->bc.reloc_offset; |
| 343 | offset < filter_bytecode->bc.len; |
| 344 | offset = next_offset) { |
| 345 | uint16_t reloc_offset = |
| 346 | *(uint16_t *) &filter_bytecode->bc.data[offset]; |
| 347 | const char *name = |
| 348 | (const char *) &filter_bytecode->bc.data[offset + sizeof(uint16_t)]; |
| 349 | |
| 350 | ret = apply_reloc(event, runtime, runtime->len, reloc_offset, name); |
| 351 | if (ret) { |
| 352 | goto link_error; |
| 353 | } |
| 354 | next_offset = offset + sizeof(uint16_t) + strlen(name) + 1; |
| 355 | } |
| 356 | /* Validate bytecode */ |
| 357 | ret = lttng_filter_validate_bytecode(runtime); |
| 358 | if (ret) { |
| 359 | goto link_error; |
| 360 | } |
| 361 | /* Specialize bytecode */ |
| 362 | ret = lttng_filter_specialize_bytecode(runtime); |
| 363 | if (ret) { |
| 364 | goto link_error; |
| 365 | } |
| 366 | runtime->p.filter = lttng_filter_interpret_bytecode; |
| 367 | runtime->p.link_failed = 0; |
| 368 | list_add_rcu(&runtime->p.node, insert_loc); |
| 369 | dbg_printk("Linking successful.\n"); |
| 370 | return 0; |
| 371 | |
| 372 | link_error: |
| 373 | runtime->p.filter = lttng_filter_false; |
| 374 | runtime->p.link_failed = 1; |
| 375 | list_add_rcu(&runtime->p.node, insert_loc); |
| 376 | alloc_error: |
| 377 | dbg_printk("Linking failed.\n"); |
| 378 | return ret; |
| 379 | } |
| 380 | |
| 381 | void lttng_filter_sync_state(struct lttng_bytecode_runtime *runtime) |
| 382 | { |
| 383 | struct lttng_filter_bytecode_node *bc = runtime->bc; |
| 384 | |
| 385 | if (!bc->enabler->enabled || runtime->link_failed) |
| 386 | runtime->filter = lttng_filter_false; |
| 387 | else |
| 388 | runtime->filter = lttng_filter_interpret_bytecode; |
| 389 | } |
| 390 | |
| 391 | /* |
| 392 | * Link bytecode for all enablers referenced by an event. |
| 393 | */ |
| 394 | void lttng_enabler_event_link_bytecode(struct lttng_event *event, |
| 395 | struct lttng_enabler *enabler) |
| 396 | { |
| 397 | struct lttng_filter_bytecode_node *bc; |
| 398 | struct lttng_bytecode_runtime *runtime; |
| 399 | |
| 400 | /* Can only be called for events with desc attached */ |
| 401 | WARN_ON_ONCE(!event->desc); |
| 402 | |
| 403 | /* Link each bytecode. */ |
| 404 | list_for_each_entry(bc, &enabler->filter_bytecode_head, node) { |
| 405 | int found = 0, ret; |
| 406 | struct list_head *insert_loc; |
| 407 | |
| 408 | list_for_each_entry(runtime, |
| 409 | &event->bytecode_runtime_head, node) { |
| 410 | if (runtime->bc == bc) { |
| 411 | found = 1; |
| 412 | break; |
| 413 | } |
| 414 | } |
| 415 | /* Skip bytecode already linked */ |
| 416 | if (found) |
| 417 | continue; |
| 418 | |
| 419 | /* |
| 420 | * Insert at specified priority (seqnum) in increasing |
| 421 | * order. |
| 422 | */ |
| 423 | list_for_each_entry_reverse(runtime, |
| 424 | &event->bytecode_runtime_head, node) { |
| 425 | if (runtime->bc->bc.seqnum < bc->bc.seqnum) { |
| 426 | /* insert here */ |
| 427 | insert_loc = &runtime->node; |
| 428 | goto add_within; |
| 429 | } |
| 430 | } |
| 431 | /* Add to head to list */ |
| 432 | insert_loc = &event->bytecode_runtime_head; |
| 433 | add_within: |
| 434 | dbg_printk("linking bytecode\n"); |
| 435 | ret = _lttng_filter_event_link_bytecode(event, bc, |
| 436 | insert_loc); |
| 437 | if (ret) { |
| 438 | dbg_printk("[lttng filter] warning: cannot link event bytecode\n"); |
| 439 | } |
| 440 | } |
| 441 | } |
| 442 | |
| 443 | /* |
| 444 | * We own the filter_bytecode if we return success. |
| 445 | */ |
| 446 | int lttng_filter_enabler_attach_bytecode(struct lttng_enabler *enabler, |
| 447 | struct lttng_filter_bytecode_node *filter_bytecode) |
| 448 | { |
| 449 | list_add(&filter_bytecode->node, &enabler->filter_bytecode_head); |
| 450 | return 0; |
| 451 | } |
| 452 | |
| 453 | void lttng_free_enabler_filter_bytecode(struct lttng_enabler *enabler) |
| 454 | { |
| 455 | struct lttng_filter_bytecode_node *filter_bytecode, *tmp; |
| 456 | |
| 457 | list_for_each_entry_safe(filter_bytecode, tmp, |
| 458 | &enabler->filter_bytecode_head, node) { |
| 459 | kfree(filter_bytecode); |
| 460 | } |
| 461 | } |
| 462 | |
| 463 | void lttng_free_event_filter_runtime(struct lttng_event *event) |
| 464 | { |
| 465 | struct bytecode_runtime *runtime, *tmp; |
| 466 | |
| 467 | list_for_each_entry_safe(runtime, tmp, |
| 468 | &event->bytecode_runtime_head, p.node) { |
| 469 | kfree(runtime); |
| 470 | } |
| 471 | } |