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![Ian Rogers](/assets/img/avatar_default.png)
This patch resolves some undefined behavior where variables in expr_id_data were accessed (for debugging) without being defined. To better enforce the tagged union behavior, the struct is moved into expr.c and accessors provided. Tag values (kinds) are explicitly identified. Signed-off-by: Ian Rogers <irogers@google.com> Reviewed-By: Kajol Jain<kjain@linux.ibm.com> Acked-by: Jiri Olsa <jolsa@redhat.com> Link: https://lore.kernel.org/r/20200826153055.2067780-1-irogers@google.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
293 lines
6.4 KiB
C
293 lines
6.4 KiB
C
// SPDX-License-Identifier: GPL-2.0
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#include <stdbool.h>
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#include <assert.h>
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#include <errno.h>
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#include <stdlib.h>
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#include <string.h>
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#include "metricgroup.h"
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#include "debug.h"
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#include "expr.h"
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#include "expr-bison.h"
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#include "expr-flex.h"
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#include <linux/kernel.h>
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#include <linux/zalloc.h>
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#include <ctype.h>
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#ifdef PARSER_DEBUG
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extern int expr_debug;
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#endif
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struct expr_id_data {
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union {
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double val;
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struct {
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double val;
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const char *metric_name;
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const char *metric_expr;
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} ref;
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struct expr_id *parent;
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};
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enum {
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/* Holding a double value. */
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EXPR_ID_DATA__VALUE,
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/* Reference to another metric. */
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EXPR_ID_DATA__REF,
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/* A reference but the value has been computed. */
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EXPR_ID_DATA__REF_VALUE,
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/* A parent is remembered for the recursion check. */
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EXPR_ID_DATA__PARENT,
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} kind;
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};
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static size_t key_hash(const void *key, void *ctx __maybe_unused)
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{
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const char *str = (const char *)key;
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size_t hash = 0;
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while (*str != '\0') {
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hash *= 31;
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hash += *str;
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str++;
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}
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return hash;
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}
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static bool key_equal(const void *key1, const void *key2,
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void *ctx __maybe_unused)
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{
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return !strcmp((const char *)key1, (const char *)key2);
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}
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/* Caller must make sure id is allocated */
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int expr__add_id(struct expr_parse_ctx *ctx, const char *id)
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{
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struct expr_id_data *data_ptr = NULL, *old_data = NULL;
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char *old_key = NULL;
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int ret;
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data_ptr = malloc(sizeof(*data_ptr));
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if (!data_ptr)
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return -ENOMEM;
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data_ptr->parent = ctx->parent;
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data_ptr->kind = EXPR_ID_DATA__PARENT;
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ret = hashmap__set(&ctx->ids, id, data_ptr,
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(const void **)&old_key, (void **)&old_data);
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if (ret)
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free(data_ptr);
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free(old_key);
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free(old_data);
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return ret;
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}
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/* Caller must make sure id is allocated */
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int expr__add_id_val(struct expr_parse_ctx *ctx, const char *id, double val)
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{
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struct expr_id_data *data_ptr = NULL, *old_data = NULL;
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char *old_key = NULL;
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int ret;
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data_ptr = malloc(sizeof(*data_ptr));
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if (!data_ptr)
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return -ENOMEM;
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data_ptr->val = val;
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data_ptr->kind = EXPR_ID_DATA__VALUE;
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ret = hashmap__set(&ctx->ids, id, data_ptr,
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(const void **)&old_key, (void **)&old_data);
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if (ret)
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free(data_ptr);
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free(old_key);
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free(old_data);
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return ret;
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}
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int expr__add_ref(struct expr_parse_ctx *ctx, struct metric_ref *ref)
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{
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struct expr_id_data *data_ptr = NULL, *old_data = NULL;
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char *old_key = NULL;
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char *name, *p;
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int ret;
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data_ptr = zalloc(sizeof(*data_ptr));
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if (!data_ptr)
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return -ENOMEM;
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name = strdup(ref->metric_name);
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if (!name) {
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free(data_ptr);
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return -ENOMEM;
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}
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/*
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* The jevents tool converts all metric expressions
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* to lowercase, including metric references, hence
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* we need to add lowercase name for metric, so it's
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* properly found.
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*/
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for (p = name; *p; p++)
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*p = tolower(*p);
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/*
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* Intentionally passing just const char pointers,
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* originally from 'struct pmu_event' object.
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* We don't need to change them, so there's no
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* need to create our own copy.
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*/
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data_ptr->ref.metric_name = ref->metric_name;
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data_ptr->ref.metric_expr = ref->metric_expr;
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data_ptr->kind = EXPR_ID_DATA__REF;
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ret = hashmap__set(&ctx->ids, name, data_ptr,
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(const void **)&old_key, (void **)&old_data);
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if (ret)
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free(data_ptr);
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pr_debug2("adding ref metric %s: %s\n",
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ref->metric_name, ref->metric_expr);
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free(old_key);
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free(old_data);
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return ret;
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}
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int expr__get_id(struct expr_parse_ctx *ctx, const char *id,
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struct expr_id_data **data)
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{
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return hashmap__find(&ctx->ids, id, (void **)data) ? 0 : -1;
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}
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int expr__resolve_id(struct expr_parse_ctx *ctx, const char *id,
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struct expr_id_data **datap)
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{
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struct expr_id_data *data;
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if (expr__get_id(ctx, id, datap) || !*datap) {
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pr_debug("%s not found\n", id);
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return -1;
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}
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data = *datap;
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switch (data->kind) {
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case EXPR_ID_DATA__VALUE:
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pr_debug2("lookup(%s): val %f\n", id, data->val);
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break;
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case EXPR_ID_DATA__PARENT:
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pr_debug2("lookup(%s): parent %s\n", id, data->parent->id);
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break;
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case EXPR_ID_DATA__REF:
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pr_debug2("lookup(%s): ref metric name %s\n", id,
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data->ref.metric_name);
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pr_debug("processing metric: %s ENTRY\n", id);
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data->kind = EXPR_ID_DATA__REF_VALUE;
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if (expr__parse(&data->ref.val, ctx, data->ref.metric_expr, 1)) {
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pr_debug("%s failed to count\n", id);
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return -1;
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}
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pr_debug("processing metric: %s EXIT: %f\n", id, data->val);
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break;
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case EXPR_ID_DATA__REF_VALUE:
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pr_debug2("lookup(%s): ref val %f metric name %s\n", id,
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data->ref.val, data->ref.metric_name);
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break;
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default:
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assert(0); /* Unreachable. */
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}
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return 0;
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}
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void expr__del_id(struct expr_parse_ctx *ctx, const char *id)
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{
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struct expr_id_data *old_val = NULL;
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char *old_key = NULL;
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hashmap__delete(&ctx->ids, id,
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(const void **)&old_key, (void **)&old_val);
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free(old_key);
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free(old_val);
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}
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void expr__ctx_init(struct expr_parse_ctx *ctx)
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{
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hashmap__init(&ctx->ids, key_hash, key_equal, NULL);
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}
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void expr__ctx_clear(struct expr_parse_ctx *ctx)
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{
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struct hashmap_entry *cur;
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size_t bkt;
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hashmap__for_each_entry((&ctx->ids), cur, bkt) {
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free((char *)cur->key);
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free(cur->value);
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}
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hashmap__clear(&ctx->ids);
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}
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static int
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__expr__parse(double *val, struct expr_parse_ctx *ctx, const char *expr,
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int start, int runtime)
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{
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struct expr_scanner_ctx scanner_ctx = {
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.start_token = start,
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.runtime = runtime,
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};
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YY_BUFFER_STATE buffer;
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void *scanner;
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int ret;
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pr_debug2("parsing metric: %s\n", expr);
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ret = expr_lex_init_extra(&scanner_ctx, &scanner);
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if (ret)
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return ret;
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buffer = expr__scan_string(expr, scanner);
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#ifdef PARSER_DEBUG
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expr_debug = 1;
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expr_set_debug(1, scanner);
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#endif
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ret = expr_parse(val, ctx, scanner);
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expr__flush_buffer(buffer, scanner);
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expr__delete_buffer(buffer, scanner);
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expr_lex_destroy(scanner);
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return ret;
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}
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int expr__parse(double *final_val, struct expr_parse_ctx *ctx,
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const char *expr, int runtime)
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{
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return __expr__parse(final_val, ctx, expr, EXPR_PARSE, runtime) ? -1 : 0;
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}
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int expr__find_other(const char *expr, const char *one,
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struct expr_parse_ctx *ctx, int runtime)
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{
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int ret = __expr__parse(NULL, ctx, expr, EXPR_OTHER, runtime);
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if (one)
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expr__del_id(ctx, one);
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return ret;
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}
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double expr_id_data__value(const struct expr_id_data *data)
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{
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if (data->kind == EXPR_ID_DATA__VALUE)
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return data->val;
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assert(data->kind == EXPR_ID_DATA__REF_VALUE);
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return data->ref.val;
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}
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struct expr_id *expr_id_data__parent(struct expr_id_data *data)
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{
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assert(data->kind == EXPR_ID_DATA__PARENT);
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return data->parent;
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}
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