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
 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 = &lttng_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 }