src/lttng-bytecode.c

   1 /* SPDX-License-Identifier: MIT
   2  *
   3  * lttng-bytecode.c
   4  *
   5  * LTTng modules bytecode code.
   6  *
   7  * Copyright (C) 2010-2016 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   8  */
   9
  10 #include <linux/list.h>
  11 #include <linux/slab.h>
  12
  13 #include <lttng/lttng-bytecode.h>
  14
  15 static const char *opnames[] = {
  16         [ BYTECODE_OP_UNKNOWN ] = "UNKNOWN",
  17
  18         [ BYTECODE_OP_RETURN ] = "RETURN",
  19
  20         /* binary */
  21         [ BYTECODE_OP_MUL ] = "MUL",
  22         [ BYTECODE_OP_DIV ] = "DIV",
  23         [ BYTECODE_OP_MOD ] = "MOD",
  24         [ BYTECODE_OP_PLUS ] = "PLUS",
  25         [ BYTECODE_OP_MINUS ] = "MINUS",
  26         [ BYTECODE_OP_BIT_RSHIFT ] = "BIT_RSHIFT",
  27         [ BYTECODE_OP_BIT_LSHIFT ] = "BIT_LSHIFT",
  28         [ BYTECODE_OP_BIT_AND ] = "BIT_AND",
  29         [ BYTECODE_OP_BIT_OR ] = "BIT_OR",
  30         [ BYTECODE_OP_BIT_XOR ] = "BIT_XOR",
  31
  32         /* binary comparators */
  33         [ BYTECODE_OP_EQ ] = "EQ",
  34         [ BYTECODE_OP_NE ] = "NE",
  35         [ BYTECODE_OP_GT ] = "GT",
  36         [ BYTECODE_OP_LT ] = "LT",
  37         [ BYTECODE_OP_GE ] = "GE",
  38         [ BYTECODE_OP_LE ] = "LE",
  39
  40         /* string binary comparators */
  41         [ BYTECODE_OP_EQ_STRING ] = "EQ_STRING",
  42         [ BYTECODE_OP_NE_STRING ] = "NE_STRING",
  43         [ BYTECODE_OP_GT_STRING ] = "GT_STRING",
  44         [ BYTECODE_OP_LT_STRING ] = "LT_STRING",
  45         [ BYTECODE_OP_GE_STRING ] = "GE_STRING",
  46         [ BYTECODE_OP_LE_STRING ] = "LE_STRING",
  47
  48         /* s64 binary comparators */
  49         [ BYTECODE_OP_EQ_S64 ] = "EQ_S64",
  50         [ BYTECODE_OP_NE_S64 ] = "NE_S64",
  51         [ BYTECODE_OP_GT_S64 ] = "GT_S64",
  52         [ BYTECODE_OP_LT_S64 ] = "LT_S64",
  53         [ BYTECODE_OP_GE_S64 ] = "GE_S64",
  54         [ BYTECODE_OP_LE_S64 ] = "LE_S64",
  55
  56         /* double binary comparators */
  57         [ BYTECODE_OP_EQ_DOUBLE ] = "EQ_DOUBLE",
  58         [ BYTECODE_OP_NE_DOUBLE ] = "NE_DOUBLE",
  59         [ BYTECODE_OP_GT_DOUBLE ] = "GT_DOUBLE",
  60         [ BYTECODE_OP_LT_DOUBLE ] = "LT_DOUBLE",
  61         [ BYTECODE_OP_GE_DOUBLE ] = "GE_DOUBLE",
  62         [ BYTECODE_OP_LE_DOUBLE ] = "LE_DOUBLE",
  63
  64         /* Mixed S64-double binary comparators */
  65         [ BYTECODE_OP_EQ_DOUBLE_S64 ] = "EQ_DOUBLE_S64",
  66         [ BYTECODE_OP_NE_DOUBLE_S64 ] = "NE_DOUBLE_S64",
  67         [ BYTECODE_OP_GT_DOUBLE_S64 ] = "GT_DOUBLE_S64",
  68         [ BYTECODE_OP_LT_DOUBLE_S64 ] = "LT_DOUBLE_S64",
  69         [ BYTECODE_OP_GE_DOUBLE_S64 ] = "GE_DOUBLE_S64",
  70         [ BYTECODE_OP_LE_DOUBLE_S64 ] = "LE_DOUBLE_S64",
  71
  72         [ BYTECODE_OP_EQ_S64_DOUBLE ] = "EQ_S64_DOUBLE",
  73         [ BYTECODE_OP_NE_S64_DOUBLE ] = "NE_S64_DOUBLE",
  74         [ BYTECODE_OP_GT_S64_DOUBLE ] = "GT_S64_DOUBLE",
  75         [ BYTECODE_OP_LT_S64_DOUBLE ] = "LT_S64_DOUBLE",
  76         [ BYTECODE_OP_GE_S64_DOUBLE ] = "GE_S64_DOUBLE",
  77         [ BYTECODE_OP_LE_S64_DOUBLE ] = "LE_S64_DOUBLE",
  78
  79         /* unary */
  80         [ BYTECODE_OP_UNARY_PLUS ] = "UNARY_PLUS",
  81         [ BYTECODE_OP_UNARY_MINUS ] = "UNARY_MINUS",
  82         [ BYTECODE_OP_UNARY_NOT ] = "UNARY_NOT",
  83         [ BYTECODE_OP_UNARY_PLUS_S64 ] = "UNARY_PLUS_S64",
  84         [ BYTECODE_OP_UNARY_MINUS_S64 ] = "UNARY_MINUS_S64",
  85         [ BYTECODE_OP_UNARY_NOT_S64 ] = "UNARY_NOT_S64",
  86         [ BYTECODE_OP_UNARY_PLUS_DOUBLE ] = "UNARY_PLUS_DOUBLE",
  87         [ BYTECODE_OP_UNARY_MINUS_DOUBLE ] = "UNARY_MINUS_DOUBLE",
  88         [ BYTECODE_OP_UNARY_NOT_DOUBLE ] = "UNARY_NOT_DOUBLE",
  89
  90         /* logical */
  91         [ BYTECODE_OP_AND ] = "AND",
  92         [ BYTECODE_OP_OR ] = "OR",
  93
  94         /* load field ref */
  95         [ BYTECODE_OP_LOAD_FIELD_REF ] = "LOAD_FIELD_REF",
  96         [ BYTECODE_OP_LOAD_FIELD_REF_STRING ] = "LOAD_FIELD_REF_STRING",
  97         [ BYTECODE_OP_LOAD_FIELD_REF_SEQUENCE ] = "LOAD_FIELD_REF_SEQUENCE",
  98         [ BYTECODE_OP_LOAD_FIELD_REF_S64 ] = "LOAD_FIELD_REF_S64",
  99         [ BYTECODE_OP_LOAD_FIELD_REF_DOUBLE ] = "LOAD_FIELD_REF_DOUBLE",
 100
 101         /* load from immediate operand */
 102         [ BYTECODE_OP_LOAD_STRING ] = "LOAD_STRING",
 103         [ BYTECODE_OP_LOAD_S64 ] = "LOAD_S64",
 104         [ BYTECODE_OP_LOAD_DOUBLE ] = "LOAD_DOUBLE",
 105
 106         /* cast */
 107         [ BYTECODE_OP_CAST_TO_S64 ] = "CAST_TO_S64",
 108         [ BYTECODE_OP_CAST_DOUBLE_TO_S64 ] = "CAST_DOUBLE_TO_S64",
 109         [ BYTECODE_OP_CAST_NOP ] = "CAST_NOP",
 110
 111         /* get context ref */
 112         [ BYTECODE_OP_GET_CONTEXT_REF ] = "GET_CONTEXT_REF",
 113         [ BYTECODE_OP_GET_CONTEXT_REF_STRING ] = "GET_CONTEXT_REF_STRING",
 114         [ BYTECODE_OP_GET_CONTEXT_REF_S64 ] = "GET_CONTEXT_REF_S64",
 115         [ BYTECODE_OP_GET_CONTEXT_REF_DOUBLE ] = "GET_CONTEXT_REF_DOUBLE",
 116
 117         /* load userspace field ref */
 118         [ BYTECODE_OP_LOAD_FIELD_REF_USER_STRING ] = "LOAD_FIELD_REF_USER_STRING",
 119         [ BYTECODE_OP_LOAD_FIELD_REF_USER_SEQUENCE ] = "LOAD_FIELD_REF_USER_SEQUENCE",
 120
 121         /*
 122          * load immediate star globbing pattern (literal string)
 123          * from immediate.
 124          */
 125         [ BYTECODE_OP_LOAD_STAR_GLOB_STRING ] = "LOAD_STAR_GLOB_STRING",
 126
 127         /* globbing pattern binary operator: apply to */
 128         [ BYTECODE_OP_EQ_STAR_GLOB_STRING ] = "EQ_STAR_GLOB_STRING",
 129         [ BYTECODE_OP_NE_STAR_GLOB_STRING ] = "NE_STAR_GLOB_STRING",
 130
 131         /*
 132          * Instructions for recursive traversal through composed types.
 133          */
 134         [ BYTECODE_OP_GET_CONTEXT_ROOT ] = "GET_CONTEXT_ROOT",
 135         [ BYTECODE_OP_GET_APP_CONTEXT_ROOT ] = "GET_APP_CONTEXT_ROOT",
 136         [ BYTECODE_OP_GET_PAYLOAD_ROOT ] = "GET_PAYLOAD_ROOT",
 137
 138         [ BYTECODE_OP_GET_SYMBOL ] = "GET_SYMBOL",
 139         [ BYTECODE_OP_GET_SYMBOL_FIELD ] = "GET_SYMBOL_FIELD",
 140         [ BYTECODE_OP_GET_INDEX_U16 ] = "GET_INDEX_U16",
 141         [ BYTECODE_OP_GET_INDEX_U64 ] = "GET_INDEX_U64",
 142
 143         [ BYTECODE_OP_LOAD_FIELD ] = "LOAD_FIELD",
 144         [ BYTECODE_OP_LOAD_FIELD_S8 ] = "LOAD_FIELD_S8",
 145         [ BYTECODE_OP_LOAD_FIELD_S16 ] = "LOAD_FIELD_S16",
 146         [ BYTECODE_OP_LOAD_FIELD_S32 ] = "LOAD_FIELD_S32",
 147         [ BYTECODE_OP_LOAD_FIELD_S64 ] = "LOAD_FIELD_S64",
 148         [ BYTECODE_OP_LOAD_FIELD_U8 ] = "LOAD_FIELD_U8",
 149         [ BYTECODE_OP_LOAD_FIELD_U16 ] = "LOAD_FIELD_U16",
 150         [ BYTECODE_OP_LOAD_FIELD_U32 ] = "LOAD_FIELD_U32",
 151         [ BYTECODE_OP_LOAD_FIELD_U64 ] = "LOAD_FIELD_U64",
 152         [ BYTECODE_OP_LOAD_FIELD_STRING ] = "LOAD_FIELD_STRING",
 153         [ BYTECODE_OP_LOAD_FIELD_SEQUENCE ] = "LOAD_FIELD_SEQUENCE",
 154         [ BYTECODE_OP_LOAD_FIELD_DOUBLE ] = "LOAD_FIELD_DOUBLE",
 155
 156         [ BYTECODE_OP_UNARY_BIT_NOT ] = "UNARY_BIT_NOT",
 157
 158         [ BYTECODE_OP_RETURN_S64 ] = "RETURN_S64",
 159 };
 160
 161 const char *lttng_bytecode_print_op(enum bytecode_op op)
 162 {
 163         if (op >= NR_BYTECODE_OPS)
 164                 return "UNKNOWN";
 165         else
 166                 return opnames[op];
 167 }
 168
 169 static
 170 int apply_field_reloc(const struct lttng_event_desc *event_desc,
 171                 struct bytecode_runtime *runtime,
 172                 uint32_t runtime_len,
 173                 uint32_t reloc_offset,
 174                 const char *field_name,
 175                 enum bytecode_op bytecode_op)
 176 {
 177         const struct lttng_event_field *fields, *field = NULL;
 178         unsigned int nr_fields, i;
 179         struct load_op *op;
 180         uint32_t field_offset = 0;
 181
 182         dbg_printk("Apply field reloc: %u %s\n", reloc_offset, field_name);
 183
 184         /* Lookup event by name */
 185         if (!event_desc)
 186                 return -EINVAL;
 187         fields = event_desc->fields;
 188         if (!fields)
 189                 return -EINVAL;
 190         nr_fields = event_desc->nr_fields;
 191         for (i = 0; i < nr_fields; i++) {
 192                 if (fields[i].nofilter)
 193                         continue;
 194                 if (!strcmp(fields[i].name, field_name)) {
 195                         field = &fields[i];
 196                         break;
 197                 }
 198                 /* compute field offset */
 199                 switch (fields[i].type.atype) {
 200                 case atype_integer:
 201                 case atype_enum_nestable:
 202                         field_offset += sizeof(int64_t);
 203                         break;
 204                 case atype_array_nestable:
 205                         if (!lttng_is_bytewise_integer(fields[i].type.u.array_nestable.elem_type))
 206                                 return -EINVAL;
 207                         field_offset += sizeof(unsigned long);
 208                         field_offset += sizeof(void *);
 209                         break;
 210                 case atype_sequence_nestable:
 211                         if (!lttng_is_bytewise_integer(fields[i].type.u.sequence_nestable.elem_type))
 212                                 return -EINVAL;
 213                         field_offset += sizeof(unsigned long);
 214                         field_offset += sizeof(void *);
 215                         break;
 216                 case atype_string:
 217                         field_offset += sizeof(void *);
 218                         break;
 219                 case atype_struct_nestable:     /* Unsupported. */
 220                 case atype_variant_nestable:    /* Unsupported. */
 221                 default:
 222                         return -EINVAL;
 223                 }
 224         }
 225         if (!field)
 226                 return -EINVAL;
 227
 228         /* Check if field offset is too large for 16-bit offset */
 229         if (field_offset > LTTNG_KERNEL_FILTER_BYTECODE_MAX_LEN - 1)
 230                 return -EINVAL;
 231
 232         /* set type */
 233         op = (struct load_op *) &runtime->code[reloc_offset];
 234
 235         switch (bytecode_op) {
 236         case BYTECODE_OP_LOAD_FIELD_REF:
 237         {
 238                 struct field_ref *field_ref;
 239
 240                 field_ref = (struct field_ref *) op->data;
 241                 switch (field->type.atype) {
 242                 case atype_integer:
 243                 case atype_enum_nestable:
 244                         op->op = BYTECODE_OP_LOAD_FIELD_REF_S64;
 245                         break;
 246                 case atype_array_nestable:
 247                 case atype_sequence_nestable:
 248                         if (field->user)
 249                                 op->op = BYTECODE_OP_LOAD_FIELD_REF_USER_SEQUENCE;
 250                         else
 251                                 op->op = BYTECODE_OP_LOAD_FIELD_REF_SEQUENCE;
 252                         break;
 253                 case atype_string:
 254                         if (field->user)
 255                                 op->op = BYTECODE_OP_LOAD_FIELD_REF_USER_STRING;
 256                         else
 257                                 op->op = BYTECODE_OP_LOAD_FIELD_REF_STRING;
 258                         break;
 259                 case atype_struct_nestable:     /* Unsupported. */
 260                 case atype_variant_nestable:    /* Unsupported. */
 261                 default:
 262                         return -EINVAL;
 263                 }
 264                 /* set offset */
 265                 field_ref->offset = (uint16_t) field_offset;
 266                 break;
 267         }
 268         default:
 269                 return -EINVAL;
 270         }
 271         return 0;
 272 }
 273
 274 static
 275 int apply_context_reloc(struct bytecode_runtime *runtime,
 276                 uint32_t runtime_len,
 277                 uint32_t reloc_offset,
 278                 const char *context_name,
 279                 enum bytecode_op bytecode_op)
 280 {
 281         struct load_op *op;
 282         struct lttng_ctx_field *ctx_field;
 283         int idx;
 284
 285         dbg_printk("Apply context reloc: %u %s\n", reloc_offset, context_name);
 286
 287         /* Get context index */
 288         idx = lttng_get_context_index(lttng_static_ctx, context_name);
 289         if (idx < 0)
 290                 return -ENOENT;
 291
 292         /* Check if idx is too large for 16-bit offset */
 293         if (idx > LTTNG_KERNEL_FILTER_BYTECODE_MAX_LEN - 1)
 294                 return -EINVAL;
 295
 296         /* Get context return type */
 297         ctx_field = &lttng_static_ctx->fields[idx];
 298         op = (struct load_op *) &runtime->code[reloc_offset];
 299
 300         switch (bytecode_op) {
 301         case BYTECODE_OP_GET_CONTEXT_REF:
 302         {
 303                 struct field_ref *field_ref;
 304
 305                 field_ref = (struct field_ref *) op->data;
 306                 switch (ctx_field->event_field.type.atype) {
 307                 case atype_integer:
 308                 case atype_enum_nestable:
 309                         op->op = BYTECODE_OP_GET_CONTEXT_REF_S64;
 310                         break;
 311                         /* Sequence and array supported as string */
 312                 case atype_string:
 313                         BUG_ON(ctx_field->event_field.user);
 314                         op->op = BYTECODE_OP_GET_CONTEXT_REF_STRING;
 315                         break;
 316                 case atype_array_nestable:
 317                         if (!lttng_is_bytewise_integer(ctx_field->event_field.type.u.array_nestable.elem_type))
 318                                 return -EINVAL;
 319                         BUG_ON(ctx_field->event_field.user);
 320                         op->op = BYTECODE_OP_GET_CONTEXT_REF_STRING;
 321                         break;
 322                 case atype_sequence_nestable:
 323                         if (!lttng_is_bytewise_integer(ctx_field->event_field.type.u.sequence_nestable.elem_type))
 324                                 return -EINVAL;
 325                         BUG_ON(ctx_field->event_field.user);
 326                         op->op = BYTECODE_OP_GET_CONTEXT_REF_STRING;
 327                         break;
 328                 case atype_struct_nestable:     /* Unsupported. */
 329                 case atype_variant_nestable:    /* Unsupported. */
 330                 default:
 331                         return -EINVAL;
 332                 }
 333                 /* set offset to context index within channel contexts */
 334                 field_ref->offset = (uint16_t) idx;
 335                 break;
 336         }
 337         default:
 338                 return -EINVAL;
 339         }
 340         return 0;
 341 }
 342
 343 static
 344 int apply_reloc(const struct lttng_event_desc *event_desc,
 345                 struct bytecode_runtime *runtime,
 346                 uint32_t runtime_len,
 347                 uint32_t reloc_offset,
 348                 const char *name)
 349 {
 350         struct load_op *op;
 351
 352         dbg_printk("Apply reloc: %u %s\n", reloc_offset, name);
 353
 354         /* Ensure that the reloc is within the code */
 355         if (runtime_len - reloc_offset < sizeof(uint16_t))
 356                 return -EINVAL;
 357
 358         op = (struct load_op *) &runtime->code[reloc_offset];
 359         switch (op->op) {
 360         case BYTECODE_OP_LOAD_FIELD_REF:
 361                 return apply_field_reloc(event_desc, runtime, runtime_len,
 362                         reloc_offset, name, op->op);
 363         case BYTECODE_OP_GET_CONTEXT_REF:
 364                 return apply_context_reloc(runtime, runtime_len,
 365                         reloc_offset, name, op->op);
 366         case BYTECODE_OP_GET_SYMBOL:
 367         case BYTECODE_OP_GET_SYMBOL_FIELD:
 368                 /*
 369                  * Will be handled by load specialize phase or
 370                  * dynamically by interpreter.
 371                  */
 372                 return 0;
 373         default:
 374                 printk(KERN_WARNING "LTTng: filter: Unknown reloc op type %u\n", op->op);
 375                 return -EINVAL;
 376         }
 377         return 0;
 378 }
 379
 380 static
 381 int bytecode_is_linked(struct lttng_bytecode_node *bytecode,
 382                 struct list_head *bytecode_runtime_head)
 383 {
 384         struct lttng_bytecode_runtime *bc_runtime;
 385
 386         list_for_each_entry(bc_runtime, bytecode_runtime_head, node) {
 387                 if (bc_runtime->bc == bytecode)
 388                         return 1;
 389         }
 390         return 0;
 391 }
 392
 393 /*
 394  * Take a bytecode with reloc table and link it to an event to create a
 395  * bytecode runtime.
 396  */
 397 static
 398 int link_bytecode(const struct lttng_event_desc *event_desc,
 399                 struct lttng_ctx *ctx,
 400                 struct lttng_bytecode_node *bytecode,
 401                 struct list_head *insert_loc)
 402 {
 403         int ret, offset, next_offset;
 404         struct bytecode_runtime *runtime = NULL;
 405         size_t runtime_alloc_len;
 406
 407         if (!bytecode)
 408                 return 0;
 409         /* Bytecode already linked */
 410         if (bytecode_is_linked(bytecode, insert_loc))
 411                 return 0;
 412
 413         dbg_printk("Linking...\n");
 414
 415         /* We don't need the reloc table in the runtime */
 416         runtime_alloc_len = sizeof(*runtime) + bytecode->bc.reloc_offset;
 417         runtime = kzalloc(runtime_alloc_len, GFP_KERNEL);
 418         if (!runtime) {
 419                 ret = -ENOMEM;
 420                 goto alloc_error;
 421         }
 422         runtime->p.bc = bytecode;
 423         runtime->p.ctx = ctx;
 424         runtime->len = bytecode->bc.reloc_offset;
 425         /* copy original bytecode */
 426         memcpy(runtime->code, bytecode->bc.data, runtime->len);
 427         /*
 428          * apply relocs. Those are a uint16_t (offset in bytecode)
 429          * followed by a string (field name).
 430          */
 431         for (offset = bytecode->bc.reloc_offset;
 432                         offset < bytecode->bc.len;
 433                         offset = next_offset) {
 434                 uint16_t reloc_offset =
 435                         *(uint16_t *) &bytecode->bc.data[offset];
 436                 const char *name =
 437                         (const char *) &bytecode->bc.data[offset + sizeof(uint16_t)];
 438
 439                 ret = apply_reloc(event_desc, runtime, runtime->len, reloc_offset, name);
 440                 if (ret) {
 441                         goto link_error;
 442                 }
 443                 next_offset = offset + sizeof(uint16_t) + strlen(name) + 1;
 444         }
 445         /* Validate bytecode */
 446         ret = lttng_bytecode_validate(runtime);
 447         if (ret) {
 448                 goto link_error;
 449         }
 450         /* Specialize bytecode */
 451         ret = lttng_bytecode_specialize(event_desc, runtime);
 452         if (ret) {
 453                 goto link_error;
 454         }
 455
 456         switch (bytecode->type) {
 457         case LTTNG_BYTECODE_NODE_TYPE_FILTER:
 458                 runtime->p.interpreter_funcs.filter = lttng_bytecode_filter_interpret;
 459                 break;
 460         case LTTNG_BYTECODE_NODE_TYPE_CAPTURE:
 461                 runtime->p.interpreter_funcs.capture = lttng_bytecode_capture_interpret_false;
 462                 break;
 463         default:
 464                 WARN_ON(1);
 465         }
 466
 467         runtime->p.link_failed = 0;
 468         list_add_rcu(&runtime->p.node, insert_loc);
 469         dbg_printk("Linking successful.\n");
 470         return 0;
 471
 472 link_error:
 473
 474         switch (bytecode->type) {
 475         case LTTNG_BYTECODE_NODE_TYPE_FILTER:
 476                 runtime->p.interpreter_funcs.filter = lttng_bytecode_filter_interpret_false;
 477                 break;
 478         case LTTNG_BYTECODE_NODE_TYPE_CAPTURE:
 479                 runtime->p.interpreter_funcs.capture = lttng_bytecode_capture_interpret_false;
 480                 break;
 481         default:
 482                 WARN_ON(1);
 483         }
 484         runtime->p.link_failed = 1;
 485         list_add_rcu(&runtime->p.node, insert_loc);
 486 alloc_error:
 487         dbg_printk("Linking failed.\n");
 488         return ret;
 489 }
 490
 491 void lttng_bytecode_filter_sync_state(struct lttng_bytecode_runtime *runtime)
 492 {
 493         struct lttng_bytecode_node *bc = runtime->bc;
 494
 495         if (!bc->enabler->enabled || runtime->link_failed)
 496                 runtime->interpreter_funcs.filter = lttng_bytecode_filter_interpret_false;
 497         else
 498                 runtime->interpreter_funcs.filter = lttng_bytecode_filter_interpret;
 499 }
 500
 501 void lttng_bytecode_capture_sync_state(struct lttng_bytecode_runtime *runtime)
 502 {
 503         struct lttng_bytecode_node *bc = runtime->bc;
 504
 505         if (!bc->enabler->enabled || runtime->link_failed)
 506                 runtime->interpreter_funcs.capture = lttng_bytecode_capture_interpret_false;
 507         else
 508                 runtime->interpreter_funcs.capture = lttng_bytecode_capture_interpret;
 509 }
 510
 511 /*
 512  * Given the lists of bytecode programs of an instance (event or event
 513  * notifier) and of a matching enabler, try to link all the enabler's bytecode
 514  * programs with the instance.
 515  *
 516  * This function is called after we confirmed that name enabler and the
 517  * instance are matching names (or glob pattern matching).
 518  */
 519 void lttng_enabler_link_bytecode(const struct lttng_event_desc *event_desc,
 520                 struct lttng_ctx *ctx,
 521                 struct list_head *instance_bytecode_head,
 522                 struct list_head *enabler_bytecode_head)
 523 {
 524         struct lttng_bytecode_node *enabler_bc;
 525         struct lttng_bytecode_runtime *runtime;
 526
 527         WARN_ON_ONCE(!event_desc);
 528
 529         /* Go over all the bytecode programs of the enabler.  */
 530         list_for_each_entry(enabler_bc, enabler_bytecode_head, node) {
 531                 int found = 0, ret;
 532                 struct list_head *insert_loc;
 533
 534                 /*
 535                  * Check if the current enabler bytecode program is already
 536                  * linked with the instance.
 537                  */
 538                 list_for_each_entry(runtime, instance_bytecode_head, node) {
 539                         if (runtime->bc == enabler_bc) {
 540                                 found = 1;
 541                                 break;
 542                         }
 543                 }
 544
 545                 /*
 546                  * Skip bytecode already linked, go to the next enabler
 547                  * bytecode program.
 548                  */
 549                 if (found)
 550                         continue;
 551
 552                 /*
 553                  * Insert at specified priority (seqnum) in increasing
 554                  * order. If there already is a bytecode of the same priority,
 555                  * insert the new bytecode right after it.
 556                  */
 557                 list_for_each_entry_reverse(runtime,
 558                                 instance_bytecode_head, node) {
 559                         if (runtime->bc->bc.seqnum <= enabler_bc->bc.seqnum) {
 560                                 /* insert here */
 561                                 insert_loc = &runtime->node;
 562                                 goto add_within;
 563                         }
 564                 }
 565                 /* Add to head to list */
 566                 insert_loc = instance_bytecode_head;
 567         add_within:
 568                 dbg_printk("linking bytecode\n");
 569                 ret = link_bytecode(event_desc, ctx, enabler_bc, insert_loc);
 570                 if (ret) {
 571                         dbg_printk("[lttng filter] warning: cannot link event bytecode\n");
 572                 }
 573         }
 574 }
 575
 576 /*
 577  * We own the filter_bytecode if we return success.
 578  */
 579 int lttng_filter_enabler_attach_bytecode(struct lttng_enabler *enabler,
 580                 struct lttng_bytecode_node *filter_bytecode)
 581 {
 582         list_add(&filter_bytecode->node, &enabler->filter_bytecode_head);
 583         return 0;
 584 }
 585
 586 void lttng_free_enabler_filter_bytecode(struct lttng_enabler *enabler)
 587 {
 588         struct lttng_bytecode_node *filter_bytecode, *tmp;
 589
 590         list_for_each_entry_safe(filter_bytecode, tmp,
 591                         &enabler->filter_bytecode_head, node) {
 592                 kfree(filter_bytecode);
 593         }
 594 }
 595
 596 void lttng_free_event_filter_runtime(struct lttng_event *event)
 597 {
 598         struct bytecode_runtime *runtime, *tmp;
 599
 600         list_for_each_entry_safe(runtime, tmp,
 601                         &event->filter_bytecode_runtime_head, p.node) {
 602                 kfree(runtime->data);
 603                 kfree(runtime);
 604         }
 605 }