+++ /dev/null
-/*
- * filter-visitor-generate-bytecode.c
- *
- * LTTng filter bytecode generation
- *
- * Copyright 2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
- *
- * SPDX-License-Identifier: LGPL-2.1-only
- *
- */
-
-#include <stdlib.h>
-#include <string.h>
-#include <common/align.h>
-#include <common/compat/errno.h>
-#include <common/compat/string.h>
-
-#include "common/align.h"
-#include "common/bytecode/bytecode.h"
-#include "common/compat/string.h"
-#include "common/macros.h"
-#include "filter-ast.h"
-#include "filter-ir.h"
-
-#ifndef max_t
-#define max_t(type, a, b) ((type) ((a) > (b) ? (a) : (b)))
-#endif
-
-static
-int recursive_visit_gen_bytecode(struct filter_parser_ctx *ctx,
- struct ir_op *node);
-
-static
-int bytecode_patch(struct lttng_bytecode_alloc **fb,
- const void *data,
- uint16_t offset,
- uint32_t len)
-{
- if (offset >= (*fb)->b.len) {
- return -EINVAL;
- }
- memcpy(&(*fb)->b.data[offset], data, len);
- return 0;
-}
-
-static
-int visit_node_root(struct filter_parser_ctx *ctx, struct ir_op *node)
-{
- int ret;
- struct return_op insn;
-
- /* Visit child */
- ret = recursive_visit_gen_bytecode(ctx, node->u.root.child);
- if (ret)
- return ret;
-
- /* Generate end of bytecode instruction */
- insn.op = BYTECODE_OP_RETURN;
- return bytecode_push(&ctx->bytecode, &insn, 1, sizeof(insn));
-}
-
-static
-int append_str(char **s, const char *append)
-{
- char *old = *s;
- char *new;
- size_t oldlen = (old == NULL) ? 0 : strlen(old);
- size_t appendlen = strlen(append);
-
- new = calloc(oldlen + appendlen + 1, 1);
- if (!new) {
- return -ENOMEM;
- }
- if (oldlen) {
- strcpy(new, old);
- }
- strcat(new, append);
- *s = new;
- free(old);
- return 0;
-}
-
-/*
- * 1: match
- * 0: no match
- * < 0: error
- */
-static
-int load_expression_legacy_match(const struct ir_load_expression *exp,
- enum bytecode_op *op_type,
- char **symbol)
-{
- const struct ir_load_expression_op *op;
- bool need_dot = false;
-
- op = exp->child;
- switch (op->type) {
- case IR_LOAD_EXPRESSION_GET_CONTEXT_ROOT:
- *op_type = BYTECODE_OP_GET_CONTEXT_REF;
- if (append_str(symbol, "$ctx.")) {
- return -ENOMEM;
- }
- need_dot = false;
- break;
- case IR_LOAD_EXPRESSION_GET_APP_CONTEXT_ROOT:
- *op_type = BYTECODE_OP_GET_CONTEXT_REF;
- if (append_str(symbol, "$app.")) {
- return -ENOMEM;
- }
- need_dot = false;
- break;
- case IR_LOAD_EXPRESSION_GET_PAYLOAD_ROOT:
- *op_type = BYTECODE_OP_LOAD_FIELD_REF;
- need_dot = false;
- break;
-
- case IR_LOAD_EXPRESSION_GET_SYMBOL:
- case IR_LOAD_EXPRESSION_GET_INDEX:
- case IR_LOAD_EXPRESSION_LOAD_FIELD:
- default:
- return 0; /* no match */
- }
-
- for (;;) {
- op = op->next;
- if (!op) {
- return 0; /* no match */
- }
- switch (op->type) {
- case IR_LOAD_EXPRESSION_LOAD_FIELD:
- goto end;
- case IR_LOAD_EXPRESSION_GET_SYMBOL:
- if (need_dot && append_str(symbol, ".")) {
- return -ENOMEM;
- }
- if (append_str(symbol, op->u.symbol)) {
- return -ENOMEM;
- }
- break;
- default:
- return 0; /* no match */
- }
- need_dot = true;
- }
-end:
- return 1; /* Legacy match */
-}
-
-/*
- * 1: legacy match
- * 0: no legacy match
- * < 0: error
- */
-static
-int visit_node_load_expression_legacy(struct filter_parser_ctx *ctx,
- const struct ir_load_expression *exp,
- const struct ir_load_expression_op *op)
-{
- struct load_op *insn = NULL;
- uint32_t insn_len = sizeof(struct load_op)
- + sizeof(struct field_ref);
- struct field_ref ref_offset;
- uint32_t reloc_offset_u32;
- uint16_t reloc_offset;
- enum bytecode_op op_type;
- char *symbol = NULL;
- int ret;
-
- ret = load_expression_legacy_match(exp, &op_type, &symbol);
- if (ret <= 0) {
- goto end;
- }
- insn = calloc(insn_len, 1);
- if (!insn) {
- ret = -ENOMEM;
- goto end;
- }
- insn->op = op_type;
- ref_offset.offset = (uint16_t) -1U;
- memcpy(insn->data, &ref_offset, sizeof(ref_offset));
- /* reloc_offset points to struct load_op */
- reloc_offset_u32 = bytecode_get_len(&ctx->bytecode->b);
- if (reloc_offset_u32 > LTTNG_FILTER_MAX_LEN - 1) {
- ret = -EINVAL;
- goto end;
- }
- reloc_offset = (uint16_t) reloc_offset_u32;
- ret = bytecode_push(&ctx->bytecode, insn, 1, insn_len);
- if (ret) {
- goto end;
- }
- /* append reloc */
- ret = bytecode_push(&ctx->bytecode_reloc, &reloc_offset,
- 1, sizeof(reloc_offset));
- if (ret) {
- goto end;
- }
- ret = bytecode_push(&ctx->bytecode_reloc, symbol,
- 1, strlen(symbol) + 1);
- if (ret) {
- goto end;
- }
- ret = 1; /* legacy */
-end:
- free(insn);
- free(symbol);
- return ret;
-}
-
-static
-int visit_node_load_expression(struct filter_parser_ctx *ctx,
- const struct ir_op *node)
-{
- struct ir_load_expression *exp;
- struct ir_load_expression_op *op;
- int ret;
-
- exp = node->u.load.u.expression;
- if (!exp) {
- return -EINVAL;
- }
- op = exp->child;
- if (!op) {
- return -EINVAL;
- }
-
- /*
- * TODO: if we remove legacy load for application contexts, we
- * need to update session bytecode parser as well.
- */
- ret = visit_node_load_expression_legacy(ctx, exp, op);
- if (ret < 0) {
- return ret;
- }
- if (ret > 0) {
- return 0; /* legacy */
- }
-
- for (; op != NULL; op = op->next) {
- switch (op->type) {
- case IR_LOAD_EXPRESSION_GET_CONTEXT_ROOT:
- {
- ret = bytecode_push_get_context_root(&ctx->bytecode);
-
- if (ret) {
- return ret;
- }
-
- break;
- }
- case IR_LOAD_EXPRESSION_GET_APP_CONTEXT_ROOT:
- {
- ret = bytecode_push_get_app_context_root(
- &ctx->bytecode);
-
- if (ret) {
- return ret;
- }
-
- break;
- }
- case IR_LOAD_EXPRESSION_GET_PAYLOAD_ROOT:
- {
- ret = bytecode_push_get_payload_root(&ctx->bytecode);
-
- if (ret) {
- return ret;
- }
-
- break;
- }
- case IR_LOAD_EXPRESSION_GET_SYMBOL:
- {
- ret = bytecode_push_get_symbol(&ctx->bytecode,
- &ctx->bytecode_reloc, op->u.symbol);
-
- if (ret) {
- return ret;
- }
-
- break;
- }
- case IR_LOAD_EXPRESSION_GET_INDEX:
- {
- ret = bytecode_push_get_index_u64(
- &ctx->bytecode, op->u.index);
-
- if (ret) {
- return ret;
- }
-
- break;
- }
- case IR_LOAD_EXPRESSION_LOAD_FIELD:
- {
- struct load_op *insn;
- uint32_t insn_len = sizeof(struct load_op);
-
- insn = calloc(insn_len, 1);
- if (!insn)
- return -ENOMEM;
- insn->op = BYTECODE_OP_LOAD_FIELD;
- ret = bytecode_push(&ctx->bytecode, insn, 1, insn_len);
- free(insn);
- if (ret) {
- return ret;
- }
- break;
- }
- }
- }
- return 0;
-}
-
-static
-int visit_node_load(struct filter_parser_ctx *ctx, struct ir_op *node)
-{
- int ret;
-
- switch (node->data_type) {
- case IR_DATA_UNKNOWN:
- default:
- fprintf(stderr, "[error] Unknown data type in %s\n",
- __func__);
- return -EINVAL;
-
- case IR_DATA_STRING:
- {
- struct load_op *insn;
- uint32_t insn_len = sizeof(struct load_op)
- + strlen(node->u.load.u.string.value) + 1;
-
- insn = calloc(insn_len, 1);
- if (!insn)
- return -ENOMEM;
-
- switch (node->u.load.u.string.type) {
- case IR_LOAD_STRING_TYPE_GLOB_STAR:
- /*
- * We explicitly tell the interpreter here that
- * this load is a full star globbing pattern so
- * that the appropriate matching function can be
- * called. Also, see comment below.
- */
- insn->op = BYTECODE_OP_LOAD_STAR_GLOB_STRING;
- break;
- default:
- /*
- * This is the "legacy" string, which includes
- * star globbing patterns with a star only at
- * the end. Both "plain" and "star at the end"
- * literal strings are handled at the same place
- * by the tracer's filter bytecode interpreter,
- * whereas full star globbing patterns (stars
- * can be anywhere in the string) is a special
- * case.
- */
- insn->op = BYTECODE_OP_LOAD_STRING;
- break;
- }
-
- strcpy(insn->data, node->u.load.u.string.value);
- ret = bytecode_push(&ctx->bytecode, insn, 1, insn_len);
- free(insn);
- return ret;
- }
- case IR_DATA_NUMERIC:
- {
- struct load_op *insn;
- uint32_t insn_len = sizeof(struct load_op)
- + sizeof(struct literal_numeric);
-
- insn = calloc(insn_len, 1);
- if (!insn)
- return -ENOMEM;
- insn->op = BYTECODE_OP_LOAD_S64;
- memcpy(insn->data, &node->u.load.u.num, sizeof(int64_t));
- ret = bytecode_push(&ctx->bytecode, insn, 1, insn_len);
- free(insn);
- return ret;
- }
- case IR_DATA_FLOAT:
- {
- struct load_op *insn;
- uint32_t insn_len = sizeof(struct load_op)
- + sizeof(struct literal_double);
-
- insn = calloc(insn_len, 1);
- if (!insn)
- return -ENOMEM;
- insn->op = BYTECODE_OP_LOAD_DOUBLE;
- memcpy(insn->data, &node->u.load.u.flt, sizeof(double));
- ret = bytecode_push(&ctx->bytecode, insn, 1, insn_len);
- free(insn);
- return ret;
- }
- case IR_DATA_EXPRESSION:
- return visit_node_load_expression(ctx, node);
- }
-}
-
-static
-int visit_node_unary(struct filter_parser_ctx *ctx, struct ir_op *node)
-{
- int ret;
- struct unary_op insn;
-
- /* Visit child */
- ret = recursive_visit_gen_bytecode(ctx, node->u.unary.child);
- if (ret)
- return ret;
-
- /* Generate end of bytecode instruction */
- switch (node->u.unary.type) {
- case AST_UNARY_UNKNOWN:
- default:
- fprintf(stderr, "[error] Unknown unary node type in %s\n",
- __func__);
- return -EINVAL;
- case AST_UNARY_PLUS:
- /* Nothing to do. */
- return 0;
- case AST_UNARY_MINUS:
- insn.op = BYTECODE_OP_UNARY_MINUS;
- return bytecode_push(&ctx->bytecode, &insn, 1, sizeof(insn));
- case AST_UNARY_NOT:
- insn.op = BYTECODE_OP_UNARY_NOT;
- return bytecode_push(&ctx->bytecode, &insn, 1, sizeof(insn));
- case AST_UNARY_BIT_NOT:
- insn.op = BYTECODE_OP_UNARY_BIT_NOT;
- return bytecode_push(&ctx->bytecode, &insn, 1, sizeof(insn));
- }
-}
-
-/*
- * Binary comparator nesting is disallowed. This allows fitting into
- * only 2 registers.
- */
-static
-int visit_node_binary(struct filter_parser_ctx *ctx, struct ir_op *node)
-{
- int ret;
- struct binary_op insn;
-
- /* Visit child */
- ret = recursive_visit_gen_bytecode(ctx, node->u.binary.left);
- if (ret)
- return ret;
- ret = recursive_visit_gen_bytecode(ctx, node->u.binary.right);
- if (ret)
- return ret;
-
- switch (node->u.binary.type) {
- case AST_OP_UNKNOWN:
- default:
- fprintf(stderr, "[error] Unknown unary node type in %s\n",
- __func__);
- return -EINVAL;
-
- case AST_OP_AND:
- case AST_OP_OR:
- fprintf(stderr, "[error] Unexpected logical node type in %s\n",
- __func__);
- return -EINVAL;
-
- case AST_OP_MUL:
- insn.op = BYTECODE_OP_MUL;
- break;
- case AST_OP_DIV:
- insn.op = BYTECODE_OP_DIV;
- break;
- case AST_OP_MOD:
- insn.op = BYTECODE_OP_MOD;
- break;
- case AST_OP_PLUS:
- insn.op = BYTECODE_OP_PLUS;
- break;
- case AST_OP_MINUS:
- insn.op = BYTECODE_OP_MINUS;
- break;
- case AST_OP_BIT_RSHIFT:
- insn.op = BYTECODE_OP_BIT_RSHIFT;
- break;
- case AST_OP_BIT_LSHIFT:
- insn.op = BYTECODE_OP_BIT_LSHIFT;
- break;
- case AST_OP_BIT_AND:
- insn.op = BYTECODE_OP_BIT_AND;
- break;
- case AST_OP_BIT_OR:
- insn.op = BYTECODE_OP_BIT_OR;
- break;
- case AST_OP_BIT_XOR:
- insn.op = BYTECODE_OP_BIT_XOR;
- break;
-
- case AST_OP_EQ:
- insn.op = BYTECODE_OP_EQ;
- break;
- case AST_OP_NE:
- insn.op = BYTECODE_OP_NE;
- break;
- case AST_OP_GT:
- insn.op = BYTECODE_OP_GT;
- break;
- case AST_OP_LT:
- insn.op = BYTECODE_OP_LT;
- break;
- case AST_OP_GE:
- insn.op = BYTECODE_OP_GE;
- break;
- case AST_OP_LE:
- insn.op = BYTECODE_OP_LE;
- break;
- }
- return bytecode_push(&ctx->bytecode, &insn, 1, sizeof(insn));
-}
-
-/*
- * A logical op always return a s64 (1 or 0).
- */
-static
-int visit_node_logical(struct filter_parser_ctx *ctx, struct ir_op *node)
-{
- int ret;
- struct logical_op insn;
- uint16_t skip_offset_loc;
- uint16_t target_loc;
-
- /* Visit left child */
- ret = recursive_visit_gen_bytecode(ctx, node->u.binary.left);
- if (ret)
- return ret;
- /* Cast to s64 if float or field ref */
- if ((node->u.binary.left->data_type == IR_DATA_FIELD_REF
- || node->u.binary.left->data_type == IR_DATA_GET_CONTEXT_REF
- || node->u.binary.left->data_type == IR_DATA_EXPRESSION)
- || node->u.binary.left->data_type == IR_DATA_FLOAT) {
- struct cast_op cast_insn;
-
- if (node->u.binary.left->data_type == IR_DATA_FIELD_REF
- || node->u.binary.left->data_type == IR_DATA_GET_CONTEXT_REF
- || node->u.binary.left->data_type == IR_DATA_EXPRESSION) {
- cast_insn.op = BYTECODE_OP_CAST_TO_S64;
- } else {
- cast_insn.op = BYTECODE_OP_CAST_DOUBLE_TO_S64;
- }
- ret = bytecode_push(&ctx->bytecode, &cast_insn,
- 1, sizeof(cast_insn));
- if (ret)
- return ret;
- }
- switch (node->u.logical.type) {
- default:
- fprintf(stderr, "[error] Unknown node type in %s\n",
- __func__);
- return -EINVAL;
-
- case AST_OP_AND:
- insn.op = BYTECODE_OP_AND;
- break;
- case AST_OP_OR:
- insn.op = BYTECODE_OP_OR;
- break;
- }
- insn.skip_offset = (uint16_t) -1UL; /* Temporary */
- ret = bytecode_push_logical(&ctx->bytecode, &insn, 1, sizeof(insn),
- &skip_offset_loc);
- if (ret)
- return ret;
- /* Visit right child */
- ret = recursive_visit_gen_bytecode(ctx, node->u.binary.right);
- if (ret)
- return ret;
- /* Cast to s64 if float or field ref */
- if ((node->u.binary.right->data_type == IR_DATA_FIELD_REF
- || node->u.binary.right->data_type == IR_DATA_GET_CONTEXT_REF
- || node->u.binary.right->data_type == IR_DATA_EXPRESSION)
- || node->u.binary.right->data_type == IR_DATA_FLOAT) {
- struct cast_op cast_insn;
-
- if (node->u.binary.right->data_type == IR_DATA_FIELD_REF
- || node->u.binary.right->data_type == IR_DATA_GET_CONTEXT_REF
- || node->u.binary.right->data_type == IR_DATA_EXPRESSION) {
- cast_insn.op = BYTECODE_OP_CAST_TO_S64;
- } else {
- cast_insn.op = BYTECODE_OP_CAST_DOUBLE_TO_S64;
- }
- ret = bytecode_push(&ctx->bytecode, &cast_insn,
- 1, sizeof(cast_insn));
- if (ret)
- return ret;
- }
- /* We now know where the logical op can skip. */
- target_loc = (uint16_t) bytecode_get_len(&ctx->bytecode->b);
- ret = bytecode_patch(&ctx->bytecode,
- &target_loc, /* Offset to jump to */
- skip_offset_loc, /* Where to patch */
- sizeof(uint16_t));
- return ret;
-}
-
-/*
- * Postorder traversal of the tree. We need the children result before
- * we can evaluate the parent.
- */
-static
-int recursive_visit_gen_bytecode(struct filter_parser_ctx *ctx,
- struct ir_op *node)
-{
- switch (node->op) {
- case IR_OP_UNKNOWN:
- default:
- fprintf(stderr, "[error] Unknown node type in %s\n",
- __func__);
- return -EINVAL;
-
- case IR_OP_ROOT:
- return visit_node_root(ctx, node);
- case IR_OP_LOAD:
- return visit_node_load(ctx, node);
- case IR_OP_UNARY:
- return visit_node_unary(ctx, node);
- case IR_OP_BINARY:
- return visit_node_binary(ctx, node);
- case IR_OP_LOGICAL:
- return visit_node_logical(ctx, node);
- }
-}
-
-void filter_bytecode_free(struct filter_parser_ctx *ctx)
-{
- if (!ctx) {
- return;
- }
-
- if (ctx->bytecode) {
- free(ctx->bytecode);
- ctx->bytecode = NULL;
- }
-
- if (ctx->bytecode_reloc) {
- free(ctx->bytecode_reloc);
- ctx->bytecode_reloc = NULL;
- }
-}
-
-int filter_visitor_bytecode_generate(struct filter_parser_ctx *ctx)
-{
- int ret;
-
- ret = bytecode_init(&ctx->bytecode);
- if (ret)
- return ret;
- ret = bytecode_init(&ctx->bytecode_reloc);
- if (ret)
- goto error;
- ret = recursive_visit_gen_bytecode(ctx, ctx->ir_root);
- if (ret)
- goto error;
-
- /* Finally, append symbol table to bytecode */
- ctx->bytecode->b.reloc_table_offset = bytecode_get_len(&ctx->bytecode->b);
- return bytecode_push(&ctx->bytecode, ctx->bytecode_reloc->b.data,
- 1, bytecode_get_len(&ctx->bytecode_reloc->b));
-
-error:
- filter_bytecode_free(ctx);
- return ret;
-}
projects / lttng-tools.git / blobdiff