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                 default:
 190                         return -EINVAL;
 191                 }
 192         }
 193         if (!field)
 194                 return -EINVAL;
 195
 196         /* Check if field offset is too large for 16-bit offset */
 197         if (field_offset > LTTNG_KERNEL_FILTER_BYTECODE_MAX_LEN - 1)
 198                 return -EINVAL;
 199
 200         /* set type */
 201         op = (struct load_op *) &runtime->data[reloc_offset];
 202         field_ref = (struct field_ref *) op->data;
 203         switch (field->type.atype) {
 204         case atype_integer:
 205         case atype_enum:
 206                 op->op = FILTER_OP_LOAD_FIELD_REF_S64;
 207                 break;
 208         case atype_array:
 209         case atype_sequence:
 210                 if (field->user)
 211                         op->op = FILTER_OP_LOAD_FIELD_REF_USER_SEQUENCE;
 212                 else
 213                         op->op = FILTER_OP_LOAD_FIELD_REF_SEQUENCE;
 214                 break;
 215         case atype_string:
 216                 if (field->user)
 217                         op->op = FILTER_OP_LOAD_FIELD_REF_USER_STRING;
 218                 else
 219                         op->op = FILTER_OP_LOAD_FIELD_REF_STRING;
 220                 break;
 221         case atype_struct:              /* Unsupported. */
 222         case atype_array_compound:      /* Unsupported. */
 223         case atype_sequence_compound:   /* Unsupported. */
 224         default:
 225                 return -EINVAL;
 226         }
 227         /* set offset */
 228         field_ref->offset = (uint16_t) field_offset;
 229         return 0;
 230 }
 231
 232 static
 233 int apply_context_reloc(struct lttng_event *event,
 234                 struct bytecode_runtime *runtime,
 235                 uint32_t runtime_len,
 236                 uint32_t reloc_offset,
 237                 const char *context_name)
 238 {
 239         struct field_ref *field_ref;
 240         struct load_op *op;
 241         struct lttng_ctx_field *ctx_field;
 242         int idx;
 243
 244         dbg_printk("Apply context reloc: %u %s\n", reloc_offset, context_name);
 245
 246         /* Get context index */
 247         idx = lttng_get_context_index(lttng_static_ctx, context_name);
 248         if (idx < 0)
 249                 return -ENOENT;
 250
 251         /* Check if idx is too large for 16-bit offset */
 252         if (idx > LTTNG_KERNEL_FILTER_BYTECODE_MAX_LEN - 1)
 253                 return -EINVAL;
 254
 255         /* Get context return type */
 256         ctx_field = &lttng_static_ctx->fields[idx];
 257         op = (struct load_op *) &runtime->data[reloc_offset];
 258         field_ref = (struct field_ref *) op->data;
 259         switch (ctx_field->event_field.type.atype) {
 260         case atype_integer:
 261         case atype_enum:
 262                 op->op = FILTER_OP_GET_CONTEXT_REF_S64;
 263                 break;
 264                 /* Sequence and array supported as string */
 265         case atype_string:
 266         case atype_array:
 267         case atype_sequence:
 268                 BUG_ON(ctx_field->event_field.user);
 269                 op->op = FILTER_OP_GET_CONTEXT_REF_STRING;
 270                 break;
 271         case atype_struct:      /* Unsupported. */
 272         case atype_array_compound:      /* Unsupported. */
 273         case atype_sequence_compound:   /* Unsupported. */
 274         default:
 275                 return -EINVAL;
 276         }
 277         /* set offset to context index within channel contexts */
 278         field_ref->offset = (uint16_t) idx;
 279         return 0;
 280 }
 281
 282 static
 283 int apply_reloc(struct lttng_event *event,
 284                 struct bytecode_runtime *runtime,
 285                 uint32_t runtime_len,
 286                 uint32_t reloc_offset,
 287                 const char *name)
 288 {
 289         struct load_op *op;
 290
 291         dbg_printk("Apply reloc: %u %s\n", reloc_offset, name);
 292
 293         /* Ensure that the reloc is within the code */
 294         if (runtime_len - reloc_offset < sizeof(uint16_t))
 295                 return -EINVAL;
 296
 297         op = (struct load_op *) &runtime->data[reloc_offset];
 298         switch (op->op) {
 299         case FILTER_OP_LOAD_FIELD_REF:
 300                 return apply_field_reloc(event, runtime, runtime_len,
 301                         reloc_offset, name);
 302         case FILTER_OP_GET_CONTEXT_REF:
 303                 return apply_context_reloc(event, runtime, runtime_len,
 304                         reloc_offset, name);
 305         default:
 306                 printk(KERN_WARNING "Unknown reloc op type %u\n", op->op);
 307                 return -EINVAL;
 308         }
 309         return 0;
 310 }
 311
 312 static
 313 int bytecode_is_linked(struct lttng_filter_bytecode_node *filter_bytecode,
 314                 struct lttng_event *event)
 315 {
 316         struct lttng_bytecode_runtime *bc_runtime;
 317
 318         list_for_each_entry(bc_runtime,
 319                         &event->bytecode_runtime_head, node) {
 320                 if (bc_runtime->bc == filter_bytecode)
 321                         return 1;
 322         }
 323         return 0;
 324 }
 325
 326 /*
 327  * Take a bytecode with reloc table and link it to an event to create a
 328  * bytecode runtime.
 329  */
 330 static
 331 int _lttng_filter_event_link_bytecode(struct lttng_event *event,
 332                 struct lttng_filter_bytecode_node *filter_bytecode,
 333                 struct list_head *insert_loc)
 334 {
 335         int ret, offset, next_offset;
 336         struct bytecode_runtime *runtime = NULL;
 337         size_t runtime_alloc_len;
 338
 339         if (!filter_bytecode)
 340                 return 0;
 341         /* Bytecode already linked */
 342         if (bytecode_is_linked(filter_bytecode, event))
 343                 return 0;
 344
 345         dbg_printk("Linking...\n");
 346
 347         /* We don't need the reloc table in the runtime */
 348         runtime_alloc_len = sizeof(*runtime) + filter_bytecode->bc.reloc_offset;
 349         runtime = kzalloc(runtime_alloc_len, GFP_KERNEL);
 350         if (!runtime) {
 351                 ret = -ENOMEM;
 352                 goto alloc_error;
 353         }
 354         runtime->p.bc = filter_bytecode;
 355         runtime->len = filter_bytecode->bc.reloc_offset;
 356         /* copy original bytecode */
 357         memcpy(runtime->data, filter_bytecode->bc.data, runtime->len);
 358         /*
 359          * apply relocs. Those are a uint16_t (offset in bytecode)
 360          * followed by a string (field name).
 361          */
 362         for (offset = filter_bytecode->bc.reloc_offset;
 363                         offset < filter_bytecode->bc.len;
 364                         offset = next_offset) {
 365                 uint16_t reloc_offset =
 366                         *(uint16_t *) &filter_bytecode->bc.data[offset];
 367                 const char *name =
 368                         (const char *) &filter_bytecode->bc.data[offset + sizeof(uint16_t)];
 369
 370                 ret = apply_reloc(event, runtime, runtime->len, reloc_offset, name);
 371                 if (ret) {
 372                         goto link_error;
 373                 }
 374                 next_offset = offset + sizeof(uint16_t) + strlen(name) + 1;
 375         }
 376         /* Validate bytecode */
 377         ret = lttng_filter_validate_bytecode(runtime);
 378         if (ret) {
 379                 goto link_error;
 380         }
 381         /* Specialize bytecode */
 382         ret = lttng_filter_specialize_bytecode(runtime);
 383         if (ret) {
 384                 goto link_error;
 385         }
 386         runtime->p.filter = lttng_filter_interpret_bytecode;
 387         runtime->p.link_failed = 0;
 388         list_add_rcu(&runtime->p.node, insert_loc);
 389         dbg_printk("Linking successful.\n");
 390         return 0;
 391
 392 link_error:
 393         runtime->p.filter = lttng_filter_false;
 394         runtime->p.link_failed = 1;
 395         list_add_rcu(&runtime->p.node, insert_loc);
 396 alloc_error:
 397         dbg_printk("Linking failed.\n");
 398         return ret;
 399 }
 400
 401 void lttng_filter_sync_state(struct lttng_bytecode_runtime *runtime)
 402 {
 403         struct lttng_filter_bytecode_node *bc = runtime->bc;
 404
 405         if (!bc->enabler->enabled || runtime->link_failed)
 406                 runtime->filter = lttng_filter_false;
 407         else
 408                 runtime->filter = lttng_filter_interpret_bytecode;
 409 }
 410
 411 /*
 412  * Link bytecode for all enablers referenced by an event.
 413  */
 414 void lttng_enabler_event_link_bytecode(struct lttng_event *event,
 415                 struct lttng_enabler *enabler)
 416 {
 417         struct lttng_filter_bytecode_node *bc;
 418         struct lttng_bytecode_runtime *runtime;
 419
 420         /* Can only be called for events with desc attached */
 421         WARN_ON_ONCE(!event->desc);
 422
 423         /* Link each bytecode. */
 424         list_for_each_entry(bc, &enabler->filter_bytecode_head, node) {
 425                 int found = 0, ret;
 426                 struct list_head *insert_loc;
 427
 428                 list_for_each_entry(runtime,
 429                                 &event->bytecode_runtime_head, node) {
 430                         if (runtime->bc == bc) {
 431                                 found = 1;
 432                                 break;
 433                         }
 434                 }
 435                 /* Skip bytecode already linked */
 436                 if (found)
 437                         continue;
 438
 439                 /*
 440                  * Insert at specified priority (seqnum) in increasing
 441                  * order.
 442                  */
 443                 list_for_each_entry_reverse(runtime,
 444                                 &event->bytecode_runtime_head, node) {
 445                         if (runtime->bc->bc.seqnum < bc->bc.seqnum) {
 446                                 /* insert here */
 447                                 insert_loc = &runtime->node;
 448                                 goto add_within;
 449                         }
 450                 }
 451                 /* Add to head to list */
 452                 insert_loc = &event->bytecode_runtime_head;
 453         add_within:
 454                 dbg_printk("linking bytecode\n");
 455                 ret = _lttng_filter_event_link_bytecode(event, bc,
 456                                 insert_loc);
 457                 if (ret) {
 458                         dbg_printk("[lttng filter] warning: cannot link event bytecode\n");
 459                 }
 460         }
 461 }
 462
 463 /*
 464  * We own the filter_bytecode if we return success.
 465  */
 466 int lttng_filter_enabler_attach_bytecode(struct lttng_enabler *enabler,
 467                 struct lttng_filter_bytecode_node *filter_bytecode)
 468 {
 469         list_add(&filter_bytecode->node, &enabler->filter_bytecode_head);
 470         return 0;
 471 }
 472
 473 void lttng_free_enabler_filter_bytecode(struct lttng_enabler *enabler)
 474 {
 475         struct lttng_filter_bytecode_node *filter_bytecode, *tmp;
 476
 477         list_for_each_entry_safe(filter_bytecode, tmp,
 478                         &enabler->filter_bytecode_head, node) {
 479                 kfree(filter_bytecode);
 480         }
 481 }
 482
 483 void lttng_free_event_filter_runtime(struct lttng_event *event)
 484 {
 485         struct bytecode_runtime *runtime, *tmp;
 486
 487         list_for_each_entry_safe(runtime, tmp,
 488                         &event->bytecode_runtime_head, p.node) {
 489                 kfree(runtime);
 490         }
 491 }