lttng-filter.c

   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         /* load userspace field ref */
 131         [ FILTER_OP_LOAD_FIELD_REF_USER_STRING ] = "LOAD_FIELD_REF_USER_STRING",
 132         [ FILTER_OP_LOAD_FIELD_REF_USER_SEQUENCE ] = "LOAD_FIELD_REF_USER_SEQUENCE",
 133 };
 134
 135 const char *lttng_filter_print_op(enum filter_op op)
 136 {
 137         if (op >= NR_FILTER_OPS)
 138                 return "UNKNOWN";
 139         else
 140                 return opnames[op];
 141 }
 142
 143 static
 144 int apply_field_reloc(struct lttng_event *event,
 145                 struct bytecode_runtime *runtime,
 146                 uint32_t runtime_len,
 147                 uint32_t reloc_offset,
 148                 const char *field_name)
 149 {
 150         const struct lttng_event_desc *desc;
 151         const struct lttng_event_field *fields, *field = NULL;
 152         unsigned int nr_fields, i;
 153         struct field_ref *field_ref;
 154         struct load_op *op;
 155         uint32_t field_offset = 0;
 156
 157         dbg_printk("Apply field reloc: %u %s\n", reloc_offset, field_name);
 158
 159         /* Lookup event by name */
 160         desc = event->desc;
 161         if (!desc)
 162                 return -EINVAL;
 163         fields = desc->fields;
 164         if (!fields)
 165                 return -EINVAL;
 166         nr_fields = desc->nr_fields;
 167         for (i = 0; i < nr_fields; i++) {
 168                 if (!strcmp(fields[i].name, field_name)) {
 169                         field = &fields[i];
 170                         break;
 171                 }
 172                 /* compute field offset */
 173                 switch (fields[i].type.atype) {
 174                 case atype_integer:
 175                 case atype_enum:
 176                         field_offset += sizeof(int64_t);
 177                         break;
 178                 case atype_array:
 179                 case atype_sequence:
 180                         field_offset += sizeof(unsigned long);
 181                         field_offset += sizeof(void *);
 182                         break;
 183                 case atype_string:
 184                         field_offset += sizeof(void *);
 185                         break;
 186                 case atype_struct:              /* Unsupported. */
 187                 case atype_array_compound:      /* Unsupported. */
 188                 case atype_sequence_compound:   /* Unsupported. */
 189                 case atype_variant:             /* Unsupported. */
 190                 default:
 191                         return -EINVAL;
 192                 }
 193         }
 194         if (!field)
 195                 return -EINVAL;
 196
 197         /* Check if field offset is too large for 16-bit offset */
 198         if (field_offset > LTTNG_KERNEL_FILTER_BYTECODE_MAX_LEN - 1)
 199                 return -EINVAL;
 200
 201         /* set type */
 202         op = (struct load_op *) &runtime->data[reloc_offset];
 203         field_ref = (struct field_ref *) op->data;
 204         switch (field->type.atype) {
 205         case atype_integer:
 206         case atype_enum:
 207                 op->op = FILTER_OP_LOAD_FIELD_REF_S64;
 208                 break;
 209         case atype_array:
 210         case atype_sequence:
 211                 if (field->user)
 212                         op->op = FILTER_OP_LOAD_FIELD_REF_USER_SEQUENCE;
 213                 else
 214                         op->op = FILTER_OP_LOAD_FIELD_REF_SEQUENCE;
 215                 break;
 216         case atype_string:
 217                 if (field->user)
 218                         op->op = FILTER_OP_LOAD_FIELD_REF_USER_STRING;
 219                 else
 220                         op->op = FILTER_OP_LOAD_FIELD_REF_STRING;
 221                 break;
 222         case atype_struct:              /* Unsupported. */
 223         case atype_array_compound:      /* Unsupported. */
 224         case atype_sequence_compound:   /* Unsupported. */
 225         case atype_variant:             /* Unsupported. */
 226         default:
 227                 return -EINVAL;
 228         }
 229         /* set offset */
 230         field_ref->offset = (uint16_t) field_offset;
 231         return 0;
 232 }
 233
 234 static
 235 int apply_context_reloc(struct lttng_event *event,
 236                 struct bytecode_runtime *runtime,
 237                 uint32_t runtime_len,
 238                 uint32_t reloc_offset,
 239                 const char *context_name)
 240 {
 241         struct field_ref *field_ref;
 242         struct load_op *op;
 243         struct lttng_ctx_field *ctx_field;
 244         int idx;
 245
 246         dbg_printk("Apply context reloc: %u %s\n", reloc_offset, context_name);
 247
 248         /* Get context index */
 249         idx = lttng_get_context_index(lttng_static_ctx, context_name);
 250         if (idx < 0)
 251                 return -ENOENT;
 252
 253         /* Check if idx is too large for 16-bit offset */
 254         if (idx > LTTNG_KERNEL_FILTER_BYTECODE_MAX_LEN - 1)
 255                 return -EINVAL;
 256
 257         /* Get context return type */
 258         ctx_field = &lttng_static_ctx->fields[idx];
 259         op = (struct load_op *) &runtime->data[reloc_offset];
 260         field_ref = (struct field_ref *) op->data;
 261         switch (ctx_field->event_field.type.atype) {
 262         case atype_integer:
 263         case atype_enum:
 264                 op->op = FILTER_OP_GET_CONTEXT_REF_S64;
 265                 break;
 266                 /* Sequence and array supported as string */
 267         case atype_string:
 268         case atype_array:
 269         case atype_sequence:
 270                 BUG_ON(ctx_field->event_field.user);
 271                 op->op = FILTER_OP_GET_CONTEXT_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         default:
 278                 return -EINVAL;
 279         }
 280         /* set offset to context index within channel contexts */
 281         field_ref->offset = (uint16_t) idx;
 282         return 0;
 283 }
 284
 285 static
 286 int apply_reloc(struct lttng_event *event,
 287                 struct bytecode_runtime *runtime,
 288                 uint32_t runtime_len,
 289                 uint32_t reloc_offset,
 290                 const char *name)
 291 {
 292         struct load_op *op;
 293
 294         dbg_printk("Apply reloc: %u %s\n", reloc_offset, name);
 295
 296         /* Ensure that the reloc is within the code */
 297         if (runtime_len - reloc_offset < sizeof(uint16_t))
 298                 return -EINVAL;
 299
 300         op = (struct load_op *) &runtime->data[reloc_offset];
 301         switch (op->op) {
 302         case FILTER_OP_LOAD_FIELD_REF:
 303                 return apply_field_reloc(event, runtime, runtime_len,
 304                         reloc_offset, name);
 305         case FILTER_OP_GET_CONTEXT_REF:
 306                 return apply_context_reloc(event, runtime, runtime_len,
 307                         reloc_offset, name);
 308         default:
 309                 printk(KERN_WARNING "Unknown reloc op type %u\n", op->op);
 310                 return -EINVAL;
 311         }
 312         return 0;
 313 }
 314
 315 static
 316 int bytecode_is_linked(struct lttng_filter_bytecode_node *filter_bytecode,
 317                 struct lttng_event *event)
 318 {
 319         struct lttng_bytecode_runtime *bc_runtime;
 320
 321         list_for_each_entry(bc_runtime,
 322                         &event->bytecode_runtime_head, node) {
 323                 if (bc_runtime->bc == filter_bytecode)
 324                         return 1;
 325         }
 326         return 0;
 327 }
 328
 329 /*
 330  * Take a bytecode with reloc table and link it to an event to create a
 331  * bytecode runtime.
 332  */
 333 static
 334 int _lttng_filter_event_link_bytecode(struct lttng_event *event,
 335                 struct lttng_filter_bytecode_node *filter_bytecode,
 336                 struct list_head *insert_loc)
 337 {
 338         int ret, offset, next_offset;
 339         struct bytecode_runtime *runtime = NULL;
 340         size_t runtime_alloc_len;
 341
 342         if (!filter_bytecode)
 343                 return 0;
 344         /* Bytecode already linked */
 345         if (bytecode_is_linked(filter_bytecode, event))
 346                 return 0;
 347
 348         dbg_printk("Linking...\n");
 349
 350         /* We don't need the reloc table in the runtime */
 351         runtime_alloc_len = sizeof(*runtime) + filter_bytecode->bc.reloc_offset;
 352         runtime = kzalloc(runtime_alloc_len, GFP_KERNEL);
 353         if (!runtime) {
 354                 ret = -ENOMEM;
 355                 goto alloc_error;
 356         }
 357         runtime->p.bc = filter_bytecode;
 358         runtime->len = filter_bytecode->bc.reloc_offset;
 359         /* copy original bytecode */
 360         memcpy(runtime->data, filter_bytecode->bc.data, runtime->len);
 361         /*
 362          * apply relocs. Those are a uint16_t (offset in bytecode)
 363          * followed by a string (field name).
 364          */
 365         for (offset = filter_bytecode->bc.reloc_offset;
 366                         offset < filter_bytecode->bc.len;
 367                         offset = next_offset) {
 368                 uint16_t reloc_offset =
 369                         *(uint16_t *) &filter_bytecode->bc.data[offset];
 370                 const char *name =
 371                         (const char *) &filter_bytecode->bc.data[offset + sizeof(uint16_t)];
 372
 373                 ret = apply_reloc(event, runtime, runtime->len, reloc_offset, name);
 374                 if (ret) {
 375                         goto link_error;
 376                 }
 377                 next_offset = offset + sizeof(uint16_t) + strlen(name) + 1;
 378         }
 379         /* Validate bytecode */
 380         ret = lttng_filter_validate_bytecode(runtime);
 381         if (ret) {
 382                 goto link_error;
 383         }
 384         /* Specialize bytecode */
 385         ret = lttng_filter_specialize_bytecode(runtime);
 386         if (ret) {
 387                 goto link_error;
 388         }
 389         runtime->p.filter = lttng_filter_interpret_bytecode;
 390         runtime->p.link_failed = 0;
 391         list_add_rcu(&runtime->p.node, insert_loc);
 392         dbg_printk("Linking successful.\n");
 393         return 0;
 394
 395 link_error:
 396         runtime->p.filter = lttng_filter_false;
 397         runtime->p.link_failed = 1;
 398         list_add_rcu(&runtime->p.node, insert_loc);
 399 alloc_error:
 400         dbg_printk("Linking failed.\n");
 401         return ret;
 402 }
 403
 404 void lttng_filter_sync_state(struct lttng_bytecode_runtime *runtime)
 405 {
 406         struct lttng_filter_bytecode_node *bc = runtime->bc;
 407
 408         if (!bc->enabler->enabled || runtime->link_failed)
 409                 runtime->filter = lttng_filter_false;
 410         else
 411                 runtime->filter = lttng_filter_interpret_bytecode;
 412 }
 413
 414 /*
 415  * Link bytecode for all enablers referenced by an event.
 416  */
 417 void lttng_enabler_event_link_bytecode(struct lttng_event *event,
 418                 struct lttng_enabler *enabler)
 419 {
 420         struct lttng_filter_bytecode_node *bc;
 421         struct lttng_bytecode_runtime *runtime;
 422
 423         /* Can only be called for events with desc attached */
 424         WARN_ON_ONCE(!event->desc);
 425
 426         /* Link each bytecode. */
 427         list_for_each_entry(bc, &enabler->filter_bytecode_head, node) {
 428                 int found = 0, ret;
 429                 struct list_head *insert_loc;
 430
 431                 list_for_each_entry(runtime,
 432                                 &event->bytecode_runtime_head, node) {
 433                         if (runtime->bc == bc) {
 434                                 found = 1;
 435                                 break;
 436                         }
 437                 }
 438                 /* Skip bytecode already linked */
 439                 if (found)
 440                         continue;
 441
 442                 /*
 443                  * Insert at specified priority (seqnum) in increasing
 444                  * order.
 445                  */
 446                 list_for_each_entry_reverse(runtime,
 447                                 &event->bytecode_runtime_head, node) {
 448                         if (runtime->bc->bc.seqnum < bc->bc.seqnum) {
 449                                 /* insert here */
 450                                 insert_loc = &runtime->node;
 451                                 goto add_within;
 452                         }
 453                 }
 454                 /* Add to head to list */
 455                 insert_loc = &event->bytecode_runtime_head;
 456         add_within:
 457                 dbg_printk("linking bytecode\n");
 458                 ret = _lttng_filter_event_link_bytecode(event, bc,
 459                                 insert_loc);
 460                 if (ret) {
 461                         dbg_printk("[lttng filter] warning: cannot link event bytecode\n");
 462                 }
 463         }
 464 }
 465
 466 /*
 467  * We own the filter_bytecode if we return success.
 468  */
 469 int lttng_filter_enabler_attach_bytecode(struct lttng_enabler *enabler,
 470                 struct lttng_filter_bytecode_node *filter_bytecode)
 471 {
 472         list_add(&filter_bytecode->node, &enabler->filter_bytecode_head);
 473         return 0;
 474 }
 475
 476 void lttng_free_enabler_filter_bytecode(struct lttng_enabler *enabler)
 477 {
 478         struct lttng_filter_bytecode_node *filter_bytecode, *tmp;
 479
 480         list_for_each_entry_safe(filter_bytecode, tmp,
 481                         &enabler->filter_bytecode_head, node) {
 482                 kfree(filter_bytecode);
 483         }
 484 }
 485
 486 void lttng_free_event_filter_runtime(struct lttng_event *event)
 487 {
 488         struct bytecode_runtime *runtime, *tmp;
 489
 490         list_for_each_entry_safe(runtime, tmp,
 491                         &event->bytecode_runtime_head, p.node) {
 492                 kfree(runtime);
 493         }
 494 }