lttng-filter.c

   1 /*
   2  * lttng-filter.c
   3  *
   4  * LTTng modules filter code.
   5  *
   6  * Copyright (C) 2010-2016 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   7  *
   8  * Permission is hereby granted, free of charge, to any person obtaining a copy
   9  * of this software and associated documentation files (the "Software"), to deal
  10  * in the Software without restriction, including without limitation the rights
  11  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  12  * copies of the Software, and to permit persons to whom the Software is
  13  * furnished to do so, subject to the following conditions:
  14  *
  15  * The above copyright notice and this permission notice shall be included in
  16  * all copies or substantial portions of the Software.
  17  *
  18  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  19  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  20  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  21  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  22  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  23  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  24  * SOFTWARE.
  25  */
  26
  27 #include <linux/list.h>
  28 #include <linux/slab.h>
  29
  30 #include <lttng-filter.h>
  31
  32 static const char *opnames[] = {
  33         [ FILTER_OP_UNKNOWN ] = "UNKNOWN",
  34
  35         [ FILTER_OP_RETURN ] = "RETURN",
  36
  37         /* binary */
  38         [ FILTER_OP_MUL ] = "MUL",
  39         [ FILTER_OP_DIV ] = "DIV",
  40         [ FILTER_OP_MOD ] = "MOD",
  41         [ FILTER_OP_PLUS ] = "PLUS",
  42         [ FILTER_OP_MINUS ] = "MINUS",
  43         [ FILTER_OP_BIT_RSHIFT ] = "BIT_RSHIFT",
  44         [ FILTER_OP_BIT_LSHIFT ] = "BIT_LSHIFT",
  45         [ FILTER_OP_BIT_AND ] = "BIT_AND",
  46         [ FILTER_OP_BIT_OR ] = "BIT_OR",
  47         [ FILTER_OP_BIT_XOR ] = "BIT_XOR",
  48
  49         /* binary comparators */
  50         [ FILTER_OP_EQ ] = "EQ",
  51         [ FILTER_OP_NE ] = "NE",
  52         [ FILTER_OP_GT ] = "GT",
  53         [ FILTER_OP_LT ] = "LT",
  54         [ FILTER_OP_GE ] = "GE",
  55         [ FILTER_OP_LE ] = "LE",
  56
  57         /* string binary comparators */
  58         [ FILTER_OP_EQ_STRING ] = "EQ_STRING",
  59         [ FILTER_OP_NE_STRING ] = "NE_STRING",
  60         [ FILTER_OP_GT_STRING ] = "GT_STRING",
  61         [ FILTER_OP_LT_STRING ] = "LT_STRING",
  62         [ FILTER_OP_GE_STRING ] = "GE_STRING",
  63         [ FILTER_OP_LE_STRING ] = "LE_STRING",
  64
  65         /* s64 binary comparators */
  66         [ FILTER_OP_EQ_S64 ] = "EQ_S64",
  67         [ FILTER_OP_NE_S64 ] = "NE_S64",
  68         [ FILTER_OP_GT_S64 ] = "GT_S64",
  69         [ FILTER_OP_LT_S64 ] = "LT_S64",
  70         [ FILTER_OP_GE_S64 ] = "GE_S64",
  71         [ FILTER_OP_LE_S64 ] = "LE_S64",
  72
  73         /* double binary comparators */
  74         [ FILTER_OP_EQ_DOUBLE ] = "EQ_DOUBLE",
  75         [ FILTER_OP_NE_DOUBLE ] = "NE_DOUBLE",
  76         [ FILTER_OP_GT_DOUBLE ] = "GT_DOUBLE",
  77         [ FILTER_OP_LT_DOUBLE ] = "LT_DOUBLE",
  78         [ FILTER_OP_GE_DOUBLE ] = "GE_DOUBLE",
  79         [ FILTER_OP_LE_DOUBLE ] = "LE_DOUBLE",
  80
  81         /* Mixed S64-double binary comparators */
  82         [ FILTER_OP_EQ_DOUBLE_S64 ] = "EQ_DOUBLE_S64",
  83         [ FILTER_OP_NE_DOUBLE_S64 ] = "NE_DOUBLE_S64",
  84         [ FILTER_OP_GT_DOUBLE_S64 ] = "GT_DOUBLE_S64",
  85         [ FILTER_OP_LT_DOUBLE_S64 ] = "LT_DOUBLE_S64",
  86         [ FILTER_OP_GE_DOUBLE_S64 ] = "GE_DOUBLE_S64",
  87         [ FILTER_OP_LE_DOUBLE_S64 ] = "LE_DOUBLE_S64",
  88
  89         [ FILTER_OP_EQ_S64_DOUBLE ] = "EQ_S64_DOUBLE",
  90         [ FILTER_OP_NE_S64_DOUBLE ] = "NE_S64_DOUBLE",
  91         [ FILTER_OP_GT_S64_DOUBLE ] = "GT_S64_DOUBLE",
  92         [ FILTER_OP_LT_S64_DOUBLE ] = "LT_S64_DOUBLE",
  93         [ FILTER_OP_GE_S64_DOUBLE ] = "GE_S64_DOUBLE",
  94         [ FILTER_OP_LE_S64_DOUBLE ] = "LE_S64_DOUBLE",
  95
  96         /* unary */
  97         [ FILTER_OP_UNARY_PLUS ] = "UNARY_PLUS",
  98         [ FILTER_OP_UNARY_MINUS ] = "UNARY_MINUS",
  99         [ FILTER_OP_UNARY_NOT ] = "UNARY_NOT",
 100         [ FILTER_OP_UNARY_PLUS_S64 ] = "UNARY_PLUS_S64",
 101         [ FILTER_OP_UNARY_MINUS_S64 ] = "UNARY_MINUS_S64",
 102         [ FILTER_OP_UNARY_NOT_S64 ] = "UNARY_NOT_S64",
 103         [ FILTER_OP_UNARY_PLUS_DOUBLE ] = "UNARY_PLUS_DOUBLE",
 104         [ FILTER_OP_UNARY_MINUS_DOUBLE ] = "UNARY_MINUS_DOUBLE",
 105         [ FILTER_OP_UNARY_NOT_DOUBLE ] = "UNARY_NOT_DOUBLE",
 106
 107         /* logical */
 108         [ FILTER_OP_AND ] = "AND",
 109         [ FILTER_OP_OR ] = "OR",
 110
 111         /* load field ref */
 112         [ FILTER_OP_LOAD_FIELD_REF ] = "LOAD_FIELD_REF",
 113         [ FILTER_OP_LOAD_FIELD_REF_STRING ] = "LOAD_FIELD_REF_STRING",
 114         [ FILTER_OP_LOAD_FIELD_REF_SEQUENCE ] = "LOAD_FIELD_REF_SEQUENCE",
 115         [ FILTER_OP_LOAD_FIELD_REF_S64 ] = "LOAD_FIELD_REF_S64",
 116         [ FILTER_OP_LOAD_FIELD_REF_DOUBLE ] = "LOAD_FIELD_REF_DOUBLE",
 117
 118         /* load from immediate operand */
 119         [ FILTER_OP_LOAD_STRING ] = "LOAD_STRING",
 120         [ FILTER_OP_LOAD_S64 ] = "LOAD_S64",
 121         [ FILTER_OP_LOAD_DOUBLE ] = "LOAD_DOUBLE",
 122
 123         /* cast */
 124         [ FILTER_OP_CAST_TO_S64 ] = "CAST_TO_S64",
 125         [ FILTER_OP_CAST_DOUBLE_TO_S64 ] = "CAST_DOUBLE_TO_S64",
 126         [ FILTER_OP_CAST_NOP ] = "CAST_NOP",
 127
 128         /* get context ref */
 129         [ FILTER_OP_GET_CONTEXT_REF ] = "GET_CONTEXT_REF",
 130         [ FILTER_OP_GET_CONTEXT_REF_STRING ] = "GET_CONTEXT_REF_STRING",
 131         [ FILTER_OP_GET_CONTEXT_REF_S64 ] = "GET_CONTEXT_REF_S64",
 132         [ FILTER_OP_GET_CONTEXT_REF_DOUBLE ] = "GET_CONTEXT_REF_DOUBLE",
 133
 134         /* load userspace field ref */
 135         [ FILTER_OP_LOAD_FIELD_REF_USER_STRING ] = "LOAD_FIELD_REF_USER_STRING",
 136         [ FILTER_OP_LOAD_FIELD_REF_USER_SEQUENCE ] = "LOAD_FIELD_REF_USER_SEQUENCE",
 137
 138         /*
 139          * load immediate star globbing pattern (literal string)
 140          * from immediate.
 141          */
 142         [ FILTER_OP_LOAD_STAR_GLOB_STRING ] = "LOAD_STAR_GLOB_STRING",
 143
 144         /* globbing pattern binary operator: apply to */
 145         [ FILTER_OP_EQ_STAR_GLOB_STRING ] = "EQ_STAR_GLOB_STRING",
 146         [ FILTER_OP_NE_STAR_GLOB_STRING ] = "NE_STAR_GLOB_STRING",
 147
 148         /*
 149          * Instructions for recursive traversal through composed types.
 150          */
 151         [ FILTER_OP_GET_CONTEXT_ROOT ] = "GET_CONTEXT_ROOT",
 152         [ FILTER_OP_GET_APP_CONTEXT_ROOT ] = "GET_APP_CONTEXT_ROOT",
 153         [ FILTER_OP_GET_PAYLOAD_ROOT ] = "GET_PAYLOAD_ROOT",
 154
 155         [ FILTER_OP_GET_SYMBOL ] = "GET_SYMBOL",
 156         [ FILTER_OP_GET_SYMBOL_FIELD ] = "GET_SYMBOL_FIELD",
 157         [ FILTER_OP_GET_INDEX_U16 ] = "GET_INDEX_U16",
 158         [ FILTER_OP_GET_INDEX_U64 ] = "GET_INDEX_U64",
 159
 160         [ FILTER_OP_LOAD_FIELD ] = "LOAD_FIELD",
 161         [ FILTER_OP_LOAD_FIELD_S8 ] = "LOAD_FIELD_S8",
 162         [ FILTER_OP_LOAD_FIELD_S16 ] = "LOAD_FIELD_S16",
 163         [ FILTER_OP_LOAD_FIELD_S32 ] = "LOAD_FIELD_S32",
 164         [ FILTER_OP_LOAD_FIELD_S64 ] = "LOAD_FIELD_S64",
 165         [ FILTER_OP_LOAD_FIELD_U8 ] = "LOAD_FIELD_U8",
 166         [ FILTER_OP_LOAD_FIELD_U16 ] = "LOAD_FIELD_U16",
 167         [ FILTER_OP_LOAD_FIELD_U32 ] = "LOAD_FIELD_U32",
 168         [ FILTER_OP_LOAD_FIELD_U64 ] = "LOAD_FIELD_U64",
 169         [ FILTER_OP_LOAD_FIELD_STRING ] = "LOAD_FIELD_STRING",
 170         [ FILTER_OP_LOAD_FIELD_SEQUENCE ] = "LOAD_FIELD_SEQUENCE",
 171         [ FILTER_OP_LOAD_FIELD_DOUBLE ] = "LOAD_FIELD_DOUBLE",
 172
 173         [ FILTER_OP_UNARY_BIT_NOT ] = "UNARY_BIT_NOT",
 174
 175         [ FILTER_OP_RETURN_S64 ] = "RETURN_S64",
 176 };
 177
 178 const char *lttng_filter_print_op(enum filter_op op)
 179 {
 180         if (op >= NR_FILTER_OPS)
 181                 return "UNKNOWN";
 182         else
 183                 return opnames[op];
 184 }
 185
 186 static
 187 int apply_field_reloc(struct lttng_event *event,
 188                 struct bytecode_runtime *runtime,
 189                 uint32_t runtime_len,
 190                 uint32_t reloc_offset,
 191                 const char *field_name,
 192                 enum filter_op filter_op)
 193 {
 194         const struct lttng_event_desc *desc;
 195         const struct lttng_event_field *fields, *field = NULL;
 196         unsigned int nr_fields, i;
 197         struct load_op *op;
 198         uint32_t field_offset = 0;
 199
 200         dbg_printk("Apply field reloc: %u %s\n", reloc_offset, field_name);
 201
 202         /* Lookup event by name */
 203         desc = event->desc;
 204         if (!desc)
 205                 return -EINVAL;
 206         fields = desc->fields;
 207         if (!fields)
 208                 return -EINVAL;
 209         nr_fields = desc->nr_fields;
 210         for (i = 0; i < nr_fields; i++) {
 211                 if (!strcmp(fields[i].name, field_name)) {
 212                         field = &fields[i];
 213                         break;
 214                 }
 215                 /* compute field offset */
 216                 switch (fields[i].type.atype) {
 217                 case atype_integer:
 218                 case atype_enum:
 219                         field_offset += sizeof(int64_t);
 220                         break;
 221                 case atype_array:
 222                 case atype_sequence:
 223                 case atype_array_bitfield:
 224                 case atype_sequence_bitfield:
 225                         field_offset += sizeof(unsigned long);
 226                         field_offset += sizeof(void *);
 227                         break;
 228                 case atype_string:
 229                         field_offset += sizeof(void *);
 230                         break;
 231                 case atype_struct:              /* Unsupported. */
 232                 case atype_array_compound:      /* Unsupported. */
 233                 case atype_sequence_compound:   /* Unsupported. */
 234                 case atype_variant:             /* Unsupported. */
 235                 default:
 236                         return -EINVAL;
 237                 }
 238         }
 239         if (!field)
 240                 return -EINVAL;
 241
 242         /* Check if field offset is too large for 16-bit offset */
 243         if (field_offset > LTTNG_KERNEL_FILTER_BYTECODE_MAX_LEN - 1)
 244                 return -EINVAL;
 245
 246         /* set type */
 247         op = (struct load_op *) &runtime->code[reloc_offset];
 248
 249         switch (filter_op) {
 250         case FILTER_OP_LOAD_FIELD_REF:
 251         {
 252                 struct field_ref *field_ref;
 253
 254                 field_ref = (struct field_ref *) op->data;
 255                 switch (field->type.atype) {
 256                 case atype_integer:
 257                 case atype_enum:
 258                         op->op = FILTER_OP_LOAD_FIELD_REF_S64;
 259                         break;
 260                 case atype_array:
 261                 case atype_sequence:
 262                         if (field->user)
 263                                 op->op = FILTER_OP_LOAD_FIELD_REF_USER_SEQUENCE;
 264                         else
 265                                 op->op = FILTER_OP_LOAD_FIELD_REF_SEQUENCE;
 266                         break;
 267                 case atype_string:
 268                         if (field->user)
 269                                 op->op = FILTER_OP_LOAD_FIELD_REF_USER_STRING;
 270                         else
 271                                 op->op = FILTER_OP_LOAD_FIELD_REF_STRING;
 272                         break;
 273                 case atype_struct:              /* Unsupported. */
 274                 case atype_array_compound:      /* Unsupported. */
 275                 case atype_sequence_compound:   /* Unsupported. */
 276                 case atype_variant:             /* Unsupported. */
 277                 case atype_array_bitfield:      /* Unsupported. */
 278                 case atype_sequence_bitfield:   /* Unsupported. */
 279                 default:
 280                         return -EINVAL;
 281                 }
 282                 /* set offset */
 283                 field_ref->offset = (uint16_t) field_offset;
 284                 break;
 285         }
 286         default:
 287                 return -EINVAL;
 288         }
 289         return 0;
 290 }
 291
 292 static
 293 int apply_context_reloc(struct lttng_event *event,
 294                 struct bytecode_runtime *runtime,
 295                 uint32_t runtime_len,
 296                 uint32_t reloc_offset,
 297                 const char *context_name,
 298                 enum filter_op filter_op)
 299 {
 300         struct load_op *op;
 301         struct lttng_ctx_field *ctx_field;
 302         int idx;
 303
 304         dbg_printk("Apply context reloc: %u %s\n", reloc_offset, context_name);
 305
 306         /* Get context index */
 307         idx = lttng_get_context_index(lttng_static_ctx, context_name);
 308         if (idx < 0)
 309                 return -ENOENT;
 310
 311         /* Check if idx is too large for 16-bit offset */
 312         if (idx > LTTNG_KERNEL_FILTER_BYTECODE_MAX_LEN - 1)
 313                 return -EINVAL;
 314
 315         /* Get context return type */
 316         ctx_field = &lttng_static_ctx->fields[idx];
 317         op = (struct load_op *) &runtime->code[reloc_offset];
 318
 319         switch (filter_op) {
 320         case FILTER_OP_GET_CONTEXT_REF:
 321         {
 322                 struct field_ref *field_ref;
 323
 324                 field_ref = (struct field_ref *) op->data;
 325                 switch (ctx_field->event_field.type.atype) {
 326                 case atype_integer:
 327                 case atype_enum:
 328                         op->op = FILTER_OP_GET_CONTEXT_REF_S64;
 329                         break;
 330                         /* Sequence and array supported as string */
 331                 case atype_string:
 332                 case atype_array:
 333                 case atype_sequence:
 334                         BUG_ON(ctx_field->event_field.user);
 335                         op->op = FILTER_OP_GET_CONTEXT_REF_STRING;
 336                         break;
 337                 case atype_struct:      /* Unsupported. */
 338                 case atype_array_compound:      /* Unsupported. */
 339                 case atype_sequence_compound:   /* Unsupported. */
 340                 case atype_variant:             /* Unsupported. */
 341                 case atype_array_bitfield:      /* Unsupported. */
 342                 case atype_sequence_bitfield:   /* Unsupported. */
 343                 default:
 344                         return -EINVAL;
 345                 }
 346                 /* set offset to context index within channel contexts */
 347                 field_ref->offset = (uint16_t) idx;
 348                 break;
 349         }
 350         default:
 351                 return -EINVAL;
 352         }
 353         return 0;
 354 }
 355
 356 static
 357 int apply_reloc(struct lttng_event *event,
 358                 struct bytecode_runtime *runtime,
 359                 uint32_t runtime_len,
 360                 uint32_t reloc_offset,
 361                 const char *name)
 362 {
 363         struct load_op *op;
 364
 365         dbg_printk("Apply reloc: %u %s\n", reloc_offset, name);
 366
 367         /* Ensure that the reloc is within the code */
 368         if (runtime_len - reloc_offset < sizeof(uint16_t))
 369                 return -EINVAL;
 370
 371         op = (struct load_op *) &runtime->code[reloc_offset];
 372         switch (op->op) {
 373         case FILTER_OP_LOAD_FIELD_REF:
 374                 return apply_field_reloc(event, runtime, runtime_len,
 375                         reloc_offset, name, op->op);
 376         case FILTER_OP_GET_CONTEXT_REF:
 377                 return apply_context_reloc(event, runtime, runtime_len,
 378                         reloc_offset, name, op->op);
 379         case FILTER_OP_GET_SYMBOL:
 380         case FILTER_OP_GET_SYMBOL_FIELD:
 381                 /*
 382                  * Will be handled by load specialize phase or
 383                  * dynamically by interpreter.
 384                  */
 385                 return 0;
 386         default:
 387                 printk(KERN_WARNING "Unknown reloc op type %u\n", op->op);
 388                 return -EINVAL;
 389         }
 390         return 0;
 391 }
 392
 393 static
 394 int bytecode_is_linked(struct lttng_filter_bytecode_node *filter_bytecode,
 395                 struct lttng_event *event)
 396 {
 397         struct lttng_bytecode_runtime *bc_runtime;
 398
 399         list_for_each_entry(bc_runtime,
 400                         &event->bytecode_runtime_head, node) {
 401                 if (bc_runtime->bc == filter_bytecode)
 402                         return 1;
 403         }
 404         return 0;
 405 }
 406
 407 /*
 408  * Take a bytecode with reloc table and link it to an event to create a
 409  * bytecode runtime.
 410  */
 411 static
 412 int _lttng_filter_event_link_bytecode(struct lttng_event *event,
 413                 struct lttng_filter_bytecode_node *filter_bytecode,
 414                 struct list_head *insert_loc)
 415 {
 416         int ret, offset, next_offset;
 417         struct bytecode_runtime *runtime = NULL;
 418         size_t runtime_alloc_len;
 419
 420         if (!filter_bytecode)
 421                 return 0;
 422         /* Bytecode already linked */
 423         if (bytecode_is_linked(filter_bytecode, event))
 424                 return 0;
 425
 426         dbg_printk("Linking...\n");
 427
 428         /* We don't need the reloc table in the runtime */
 429         runtime_alloc_len = sizeof(*runtime) + filter_bytecode->bc.reloc_offset;
 430         runtime = kzalloc(runtime_alloc_len, GFP_KERNEL);
 431         if (!runtime) {
 432                 ret = -ENOMEM;
 433                 goto alloc_error;
 434         }
 435         runtime->p.bc = filter_bytecode;
 436         runtime->p.event = event;
 437         runtime->len = filter_bytecode->bc.reloc_offset;
 438         /* copy original bytecode */
 439         memcpy(runtime->code, filter_bytecode->bc.data, runtime->len);
 440         /*
 441          * apply relocs. Those are a uint16_t (offset in bytecode)
 442          * followed by a string (field name).
 443          */
 444         for (offset = filter_bytecode->bc.reloc_offset;
 445                         offset < filter_bytecode->bc.len;
 446                         offset = next_offset) {
 447                 uint16_t reloc_offset =
 448                         *(uint16_t *) &filter_bytecode->bc.data[offset];
 449                 const char *name =
 450                         (const char *) &filter_bytecode->bc.data[offset + sizeof(uint16_t)];
 451
 452                 ret = apply_reloc(event, runtime, runtime->len, reloc_offset, name);
 453                 if (ret) {
 454                         goto link_error;
 455                 }
 456                 next_offset = offset + sizeof(uint16_t) + strlen(name) + 1;
 457         }
 458         /* Validate bytecode */
 459         ret = lttng_filter_validate_bytecode(runtime);
 460         if (ret) {
 461                 goto link_error;
 462         }
 463         /* Specialize bytecode */
 464         ret = lttng_filter_specialize_bytecode(event, runtime);
 465         if (ret) {
 466                 goto link_error;
 467         }
 468         runtime->p.filter = lttng_filter_interpret_bytecode;
 469         runtime->p.link_failed = 0;
 470         list_add_rcu(&runtime->p.node, insert_loc);
 471         dbg_printk("Linking successful.\n");
 472         return 0;
 473
 474 link_error:
 475         runtime->p.filter = lttng_filter_false;
 476         runtime->p.link_failed = 1;
 477         list_add_rcu(&runtime->p.node, insert_loc);
 478 alloc_error:
 479         dbg_printk("Linking failed.\n");
 480         return ret;
 481 }
 482
 483 void lttng_filter_sync_state(struct lttng_bytecode_runtime *runtime)
 484 {
 485         struct lttng_filter_bytecode_node *bc = runtime->bc;
 486
 487         if (!bc->enabler->enabled || runtime->link_failed)
 488                 runtime->filter = lttng_filter_false;
 489         else
 490                 runtime->filter = lttng_filter_interpret_bytecode;
 491 }
 492
 493 /*
 494  * Link bytecode for all enablers referenced by an event.
 495  */
 496 void lttng_enabler_event_link_bytecode(struct lttng_event *event,
 497                 struct lttng_enabler *enabler)
 498 {
 499         struct lttng_filter_bytecode_node *bc;
 500         struct lttng_bytecode_runtime *runtime;
 501
 502         /* Can only be called for events with desc attached */
 503         WARN_ON_ONCE(!event->desc);
 504
 505         /* Link each bytecode. */
 506         list_for_each_entry(bc, &enabler->filter_bytecode_head, node) {
 507                 int found = 0, ret;
 508                 struct list_head *insert_loc;
 509
 510                 list_for_each_entry(runtime,
 511                                 &event->bytecode_runtime_head, node) {
 512                         if (runtime->bc == bc) {
 513                                 found = 1;
 514                                 break;
 515                         }
 516                 }
 517                 /* Skip bytecode already linked */
 518                 if (found)
 519                         continue;
 520
 521                 /*
 522                  * Insert at specified priority (seqnum) in increasing
 523                  * order.
 524                  */
 525                 list_for_each_entry_reverse(runtime,
 526                                 &event->bytecode_runtime_head, node) {
 527                         if (runtime->bc->bc.seqnum < bc->bc.seqnum) {
 528                                 /* insert here */
 529                                 insert_loc = &runtime->node;
 530                                 goto add_within;
 531                         }
 532                 }
 533                 /* Add to head to list */
 534                 insert_loc = &event->bytecode_runtime_head;
 535         add_within:
 536                 dbg_printk("linking bytecode\n");
 537                 ret = _lttng_filter_event_link_bytecode(event, bc,
 538                                 insert_loc);
 539                 if (ret) {
 540                         dbg_printk("[lttng filter] warning: cannot link event bytecode\n");
 541                 }
 542         }
 543 }
 544
 545 /*
 546  * We own the filter_bytecode if we return success.
 547  */
 548 int lttng_filter_enabler_attach_bytecode(struct lttng_enabler *enabler,
 549                 struct lttng_filter_bytecode_node *filter_bytecode)
 550 {
 551         list_add(&filter_bytecode->node, &enabler->filter_bytecode_head);
 552         return 0;
 553 }
 554
 555 void lttng_free_enabler_filter_bytecode(struct lttng_enabler *enabler)
 556 {
 557         struct lttng_filter_bytecode_node *filter_bytecode, *tmp;
 558
 559         list_for_each_entry_safe(filter_bytecode, tmp,
 560                         &enabler->filter_bytecode_head, node) {
 561                 kfree(filter_bytecode);
 562         }
 563 }
 564
 565 void lttng_free_event_filter_runtime(struct lttng_event *event)
 566 {
 567         struct bytecode_runtime *runtime, *tmp;
 568
 569         list_for_each_entry_safe(runtime, tmp,
 570                         &event->bytecode_runtime_head, p.node) {
 571                 kfree(runtime->data);
 572                 kfree(runtime);
 573         }
 574 }