src: remove xfree() and use plain free()

xmalloc() (and similar x-functions) are used for allocation. They wrap
malloc()/realloc() but will abort the program on ENOMEM.

The meaning of xmalloc() is that it wraps malloc() but aborts on
failure. I don't think x-functions should have the notion, that this
were potentially a different memory allocator that must be paired
with a particular xfree().

Even if the original intent was that the allocator is abstracted (and
possibly not backed by standard malloc()/free()), then that doesn't seem
a good idea. Nowadays libc allocators are pretty good, and we would need
a very special use cases to switch to something else. In other words,
it will never happen that xmalloc() is not backed by malloc().

Also there were a few places, where a xmalloc() was already "wrongly"
paired with free() (for example, iface_cache_release(), exit_cookie(),
nft_run_cmd_from_buffer()).

Or note how pid2name() returns an allocated string from fscanf(), which
needs to be freed with free() (and not xfree()). This requirement
bubbles up the callers portid2name() and name_by_portid(). This case was
actually handled correctly and the buffer was freed with free(). But it
shows that mixing different allocators is cumbersome to get right.  Of
course, we don't actually have different allocators and whether to use
free() or xfree() makes no different. The point is that xfree() serves
no actual purpose except raising irrelevant questions about whether
x-functions are correctly paired with xfree().

Note that xfree() also used to accept const pointers. It is bad to
unconditionally for all deallocations. Instead prefer to use plain
free(). To free a const pointer use free_const() which obviously wraps
free, as indicated by the name.

Signed-off-by: Thomas Haller <thaller@redhat.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

20 files changed, 61 insertions, 67 deletions

diff --git a/include/utils.h b/include/utils.h
index 36a28f89..e18fabec 100644
--- a/include/utils.h
+++ b/include/utils.h
@@ -142,7 +142,6 @@ extern void __memory_allocation_error(const char *filename, uint32_t line) __nor
 #define memory_allocation_error()		\
 	__memory_allocation_error(__FILE__, __LINE__);
 
-extern void xfree(const void *ptr);
 extern void *xmalloc(size_t size);
 extern void *xmalloc_array(size_t nmemb, size_t size);
 extern void *xrealloc(void *ptr, size_t size);
diff --git a/src/cache.c b/src/cache.c
index 4e89fe13..b7f46c00 100644
--- a/src/cache.c
+++ b/src/cache.c
@@ -126,9 +126,9 @@ void nft_cache_filter_fini(struct nft_cache_filter *filter)
 		struct nft_filter_obj *obj, *next;
 
 		list_for_each_entry_safe(obj, next, &filter->obj[i].head, list)
-			xfree(obj);
+			free(obj);
 	}
-	xfree(filter);
+	free(filter);
 }
 
 static void cache_filter_add(struct nft_cache_filter *filter,
@@ -1279,7 +1279,7 @@ void cache_init(struct cache *cache)
 
 void cache_free(struct cache *cache)
 {
-	xfree(cache->ht);
+	free(cache->ht);
 }
 
 void cache_add(struct cache_item *item, struct cache *cache, uint32_t hash)
diff --git a/src/datatype.c b/src/datatype.c
index ca251138..86d55a52 100644
--- a/src/datatype.c
+++ b/src/datatype.c
@@ -1268,7 +1268,7 @@ void datatype_free(const struct datatype *ptr)
 
 	free_const(dtype->name);
 	free_const(dtype->desc);
-	xfree(dtype);
+	free(dtype);
 }
 
 const struct datatype *concat_type_alloc(uint32_t type)
@@ -1515,7 +1515,7 @@ static void cgroupv2_type_print(const struct expr *expr,
 	else
 		nft_print(octx, "%" PRIu64, id);
 
-	xfree(cgroup_path);
+	free(cgroup_path);
 }
 
 static struct error_record *cgroupv2_type_parse(struct parse_ctx *ctx,
diff --git a/src/erec.c b/src/erec.c
index cd9f62be..fe66abbe 100644
--- a/src/erec.c
+++ b/src/erec.c
@@ -43,8 +43,8 @@ void erec_add_location(struct error_record *erec, const struct location *loc)
 
 void erec_destroy(struct error_record *erec)
 {
-	xfree(erec->msg);
-	xfree(erec);
+	free(erec->msg);
+	free(erec);
 }
 
 __attribute__((format(printf, 3, 0)))
@@ -203,7 +203,7 @@ void erec_print(struct output_ctx *octx, const struct error_record *erec,
 		}
 		pbuf[end] = '\0';
 		fprintf(f, "%s", pbuf);
-		xfree(pbuf);
+		free(pbuf);
 	}
 	fprintf(f, "\n");
 }
diff --git a/src/evaluate.c b/src/evaluate.c
index a2cb4dda..d1ec6ec4 100644
--- a/src/evaluate.c
+++ b/src/evaluate.c
@@ -3254,7 +3254,7 @@ static int stmt_reject_gen_dependency(struct eval_ctx *ctx, struct stmt *stmt,
 	 */
 	list_add(&nstmt->list, &ctx->rule->stmts);
 out:
-	xfree(payload);
+	free(payload);
 	return ret;
 }
 
@@ -5153,7 +5153,7 @@ static int ct_timeout_evaluate(struct eval_ctx *ctx, struct obj *obj)
 		ct->timeout[ts->timeout_index] = ts->timeout_value;
 		list_del(&ts->head);
 		free_const(ts->timeout_str);
-		xfree(ts);
+		free(ts);
 	}
 
 	return 0;
diff --git a/src/expression.c b/src/expression.c
index 0b4a537a..dde48b6a 100644
--- a/src/expression.c
+++ b/src/expression.c
@@ -94,7 +94,7 @@ void expr_free(struct expr *expr)
 	 */
 	if (expr->etype != EXPR_INVALID)
 		expr_destroy(expr);
-	xfree(expr);
+	free(expr);
 }
 
 void expr_print(const struct expr *expr, struct output_ctx *octx)
diff --git a/src/json.c b/src/json.c
index 068c423a..23bd2472 100644
--- a/src/json.c
+++ b/src/json.c
@@ -83,7 +83,7 @@ static json_t *set_dtype_json(const struct expr *key)
 			json_array_append_new(root, jtok);
 		tok = strtok_r(NULL, " .", &tok_safe);
 	}
-	xfree(namedup);
+	free(namedup);
 	return root;
 }
 
diff --git a/src/libnftables.c b/src/libnftables.c
index 866b5c6b..ec902009 100644
--- a/src/libnftables.c
+++ b/src/libnftables.c
@@ -158,7 +158,7 @@ void nft_ctx_clear_vars(struct nft_ctx *ctx)
 		free_const(ctx->vars[i].value);
 	}
 	ctx->num_vars = 0;
-	xfree(ctx->vars);
+	free(ctx->vars);
 }
 
 EXPORT_SYMBOL(nft_ctx_add_include_path);
@@ -182,9 +182,9 @@ EXPORT_SYMBOL(nft_ctx_clear_include_paths);
 void nft_ctx_clear_include_paths(struct nft_ctx *ctx)
 {
 	while (ctx->num_include_paths)
-		xfree(ctx->include_paths[--ctx->num_include_paths]);
+		free(ctx->include_paths[--ctx->num_include_paths]);
 
-	xfree(ctx->include_paths);
+	free(ctx->include_paths);
 	ctx->include_paths = NULL;
 }
 
@@ -343,9 +343,9 @@ void nft_ctx_free(struct nft_ctx *ctx)
 	nft_ctx_clear_vars(ctx);
 	nft_ctx_clear_include_paths(ctx);
 	scope_free(ctx->top_scope);
-	xfree(ctx->state);
+	free(ctx->state);
 	nft_exit(ctx);
-	xfree(ctx);
+	free(ctx);
 }
 
 EXPORT_SYMBOL(nft_ctx_set_output);
@@ -745,7 +745,7 @@ err:
 			if (indesc->name)
 				free_const(indesc->name);
 
-			xfree(indesc);
+			free(indesc);
 		}
 	}
 	free_const(nft->vars_ctx.buf);
diff --git a/src/meta.c b/src/meta.c
index 7846aefe..d7f810ce 100644
--- a/src/meta.c
+++ b/src/meta.c
@@ -99,13 +99,13 @@ static struct error_record *tchandle_type_parse(struct parse_ctx *ctx,
 		handle = strtoull(sym->identifier, NULL, 0);
 	}
 out:
-	xfree(str);
+	free(str);
 	*res = constant_expr_alloc(&sym->location, sym->dtype,
 				   BYTEORDER_HOST_ENDIAN,
 				   sizeof(handle) * BITS_PER_BYTE, &handle);
 	return NULL;
 err:
-	xfree(str);
+	free(str);
 	return error(&sym->location, "Could not parse %s", sym->dtype->desc);
 }
 
diff --git a/src/misspell.c b/src/misspell.c
index c1e58a0e..f5354fa8 100644
--- a/src/misspell.c
+++ b/src/misspell.c
@@ -72,7 +72,7 @@ static unsigned int string_distance(const char *a, const char *b)
 
 	ret = DISTANCE(len_a, len_b);
 
-	xfree(distance);
+	free(distance);
 
 	return ret;
 }
diff --git a/src/mnl.c b/src/mnl.c
index 0158924c..9e4bfcd9 100644
--- a/src/mnl.c
+++ b/src/mnl.c
@@ -242,7 +242,7 @@ static void mnl_err_list_node_add(struct list_head *err_list, int error,
 void mnl_err_list_free(struct mnl_err *err)
 {
 	list_del(&err->head);
-	xfree(err);
+	free(err);
 }
 
 static void mnl_set_sndbuffer(struct netlink_ctx *ctx)
@@ -2179,7 +2179,7 @@ static void basehook_free(struct basehook *b)
 	free_const(b->hookfn);
 	free_const(b->chain);
 	free_const(b->table);
-	xfree(b);
+	free(b);
 }
 
 static void basehook_list_add_tail(struct basehook *b, struct list_head *head)
diff --git a/src/netlink_linearize.c b/src/netlink_linearize.c
index 0c623411..df395bac 100644
--- a/src/netlink_linearize.c
+++ b/src/netlink_linearize.c
@@ -1743,9 +1743,9 @@ void netlink_linearize_fini(struct netlink_linearize_ctx *lctx)
 
 	for (i = 0; i < NFT_EXPR_LOC_HSIZE; i++) {
 		list_for_each_entry_safe(eloc, next, &lctx->expr_loc_htable[i], hlist)
-			xfree(eloc);
+			free(eloc);
 	}
-	xfree(lctx->expr_loc_htable);
+	free(lctx->expr_loc_htable);
 }
 
 void netlink_linearize_rule(struct netlink_ctx *ctx,
diff --git a/src/optimize.c b/src/optimize.c
index 9ae9283d..b90dd995 100644
--- a/src/optimize.c
+++ b/src/optimize.c
@@ -1347,16 +1347,16 @@ static int chain_optimize(struct nft_ctx *nft, struct list_head *rules)
 	}
 	ret = 0;
 	for (i = 0; i < ctx->num_rules; i++)
-		xfree(ctx->stmt_matrix[i]);
+		free(ctx->stmt_matrix[i]);
 
-	xfree(ctx->stmt_matrix);
-	xfree(merge);
+	free(ctx->stmt_matrix);
+	free(merge);
 err:
 	for (i = 0; i < ctx->num_stmts; i++)
 		stmt_free(ctx->stmt[i]);
 
-	xfree(ctx->rule);
-	xfree(ctx);
+	free(ctx->rule);
+	free(ctx);
 
 	return ret;
 }
diff --git a/src/parser_bison.y b/src/parser_bison.y
index fdbf307a..1e8169c4 100644
--- a/src/parser_bison.y
+++ b/src/parser_bison.y
@@ -712,7 +712,7 @@ int nft_lex(void *, void *, void *);
 %destructor { free_const($$); }	extended_prio_name quota_unit	basehook_device_name
 
 %type <expr>			dev_spec
-%destructor { xfree($$); }	dev_spec
+%destructor { free($$); }	dev_spec
 
 %type <table>			table_block_alloc table_block
 %destructor { close_scope(state); table_free($$); }	table_block_alloc
@@ -739,7 +739,7 @@ int nft_lex(void *, void *, void *);
 %destructor { obj_free($$); }	obj_block_alloc
 
 %type <list>			stmt_list stateful_stmt_list set_elem_stmt_list
-%destructor { stmt_list_free($$); xfree($$); } stmt_list stateful_stmt_list set_elem_stmt_list
+%destructor { stmt_list_free($$); free($$); } stmt_list stateful_stmt_list set_elem_stmt_list
 %type <stmt>			stmt match_stmt verdict_stmt set_elem_stmt
 %destructor { stmt_free($$); }	stmt match_stmt verdict_stmt set_elem_stmt
 %type <stmt>			counter_stmt counter_stmt_alloc stateful_stmt last_stmt
@@ -965,7 +965,7 @@ int nft_lex(void *, void *, void *);
 %type <val>			ct_l4protoname ct_obj_type ct_cmd_type
 
 %type <list>			timeout_states timeout_state
-%destructor { xfree($$); }	timeout_states timeout_state
+%destructor { free($$); }	timeout_states timeout_state
 
 %type <val>			xfrm_state_key	xfrm_state_proto_key xfrm_dir	xfrm_spnum
 %type <expr>			xfrm_expr
@@ -3021,7 +3021,7 @@ rule_alloc		:	stmt_list
 				list_for_each_entry(i, $1, list)
 					$$->num_stmts++;
 				list_splice_tail($1, &$$->stmts);
-				xfree($1);
+				free($1);
 			}
 			;
 
@@ -4528,7 +4528,7 @@ set_elem_expr		:	set_elem_expr_alloc
 			{
 				$$ = $1;
 				list_splice_tail($3, &$$->stmt_list);
-				xfree($3);
+				free($3);
 			}
 			;
 
@@ -4540,7 +4540,7 @@ set_elem_expr_alloc	:	set_elem_key_expr	set_elem_stmt_list
 			{
 				$$ = set_elem_expr_alloc(&@1, $1);
 				list_splice_tail($2, &$$->stmt_list);
-				xfree($2);
+				free($2);
 			}
 			|	set_elem_key_expr
 			{
@@ -4852,7 +4852,7 @@ ct_timeout_config	:	PROTOCOL	ct_l4protoname	stmt_separator
 
 				ct = &$<obj>0->ct_timeout;
 				list_splice_tail($4, &ct->timeout_list);
-				xfree($4);
+				free($4);
 			}
 			|	L3PROTOCOL	family_spec_explicit	stmt_separator
 			{
diff --git a/src/rule.c b/src/rule.c
index b40a54d7..172ba1f6 100644
--- a/src/rule.c
+++ b/src/rule.c
@@ -200,7 +200,7 @@ void set_free(struct set *set)
 		stmt_free(stmt);
 	expr_free(set->key);
 	expr_free(set->data);
-	xfree(set);
+	free(set);
 }
 
 struct set *set_lookup_fuzzy(const char *set_name,
@@ -480,7 +480,7 @@ void rule_free(struct rule *rule)
 	stmt_list_free(&rule->stmts);
 	handle_free(&rule->handle);
 	free_const(rule->comment);
-	xfree(rule);
+	free(rule);
 }
 
 void rule_print(const struct rule *rule, struct output_ctx *octx)
@@ -559,14 +559,14 @@ void scope_release(const struct scope *scope)
 		list_del(&sym->list);
 		free_const(sym->identifier);
 		expr_free(sym->expr);
-		xfree(sym);
+		free(sym);
 	}
 }
 
 void scope_free(struct scope *scope)
 {
 	scope_release(scope);
-	xfree(scope);
+	free(scope);
 }
 
 void symbol_bind(struct scope *scope, const char *identifier, struct expr *expr)
@@ -599,7 +599,7 @@ static void symbol_put(struct symbol *sym)
 	if (--sym->refcnt == 0) {
 		free_const(sym->identifier);
 		expr_free(sym->expr);
-		xfree(sym);
+		free(sym);
 	}
 }
 
@@ -734,11 +734,11 @@ void chain_free(struct chain *chain)
 	expr_free(chain->dev_expr);
 	for (i = 0; i < chain->dev_array_len; i++)
 		free_const(chain->dev_array[i]);
-	xfree(chain->dev_array);
+	free(chain->dev_array);
 	expr_free(chain->priority.expr);
 	expr_free(chain->policy);
 	free_const(chain->comment);
-	xfree(chain);
+	free(chain);
 }
 
 struct chain *chain_binding_lookup(const struct table *table,
@@ -1181,7 +1181,7 @@ void table_free(struct table *table)
 	cache_free(&table->set_cache);
 	cache_free(&table->obj_cache);
 	cache_free(&table->ft_cache);
-	xfree(table);
+	free(table);
 }
 
 struct table *table_get(struct table *table)
@@ -1330,7 +1330,7 @@ struct markup *markup_alloc(uint32_t format)
 
 void markup_free(struct markup *m)
 {
-	xfree(m);
+	free(m);
 }
 
 struct monitor *monitor_alloc(uint32_t format, uint32_t type, const char *event)
@@ -1349,7 +1349,7 @@ struct monitor *monitor_alloc(uint32_t format, uint32_t type, const char *event)
 void monitor_free(struct monitor *m)
 {
 	free_const(m->event);
-	xfree(m);
+	free(m);
 }
 
 void cmd_free(struct cmd *cmd)
@@ -1403,9 +1403,9 @@ void cmd_free(struct cmd *cmd)
 			BUG("invalid command object type %u\n", cmd->obj);
 		}
 	}
-	xfree(cmd->attr);
+	free(cmd->attr);
 	free_const(cmd->arg);
-	xfree(cmd);
+	free(cmd);
 }
 
 #include <netlink.h>
@@ -1650,10 +1650,10 @@ void obj_free(struct obj *obj)
 		list_for_each_entry_safe(ts, next, &obj->ct_timeout.timeout_list, head) {
 			list_del(&ts->head);
 			free_const(ts->timeout_str);
-			xfree(ts);
+			free(ts);
 		}
 	}
-	xfree(obj);
+	free(obj);
 }
 
 struct obj *obj_lookup_fuzzy(const char *obj_name,
@@ -2063,9 +2063,9 @@ void flowtable_free(struct flowtable *flowtable)
 	if (flowtable->dev_array != NULL) {
 		for (i = 0; i < flowtable->dev_array_len; i++)
 			free_const(flowtable->dev_array[i]);
-		xfree(flowtable->dev_array);
+		free(flowtable->dev_array);
 	}
-	xfree(flowtable);
+	free(flowtable);
 }
 
 static void flowtable_print_declaration(const struct flowtable *flowtable,
diff --git a/src/scanner.l b/src/scanner.l
index 93a31f27..00a09485 100644
--- a/src/scanner.l
+++ b/src/scanner.l
@@ -1284,7 +1284,7 @@ void scanner_destroy(struct nft_ctx *nft)
 	struct parser_state *state = yyget_extra(nft->scanner);
 
 	input_descriptor_list_destroy(state);
-	xfree(state->startcond_active);
+	free(state->startcond_active);
 
 	yylex_destroy(nft->scanner);
 }
diff --git a/src/segtree.c b/src/segtree.c
index 28172b30..5e6f857f 100644
--- a/src/segtree.c
+++ b/src/segtree.c
@@ -632,6 +632,6 @@ out:
 	if (catchall)
 		compound_expr_add(set, catchall);
 
-	xfree(ranges);
-	xfree(elements);
+	free(ranges);
+	free(elements);
 }
diff --git a/src/statement.c b/src/statement.c
index 994b522c..ab144d63 100644
--- a/src/statement.c
+++ b/src/statement.c
@@ -51,7 +51,7 @@ void stmt_free(struct stmt *stmt)
 		return;
 	if (stmt->ops->destroy)
 		stmt->ops->destroy(stmt);
-	xfree(stmt);
+	free(stmt);
 }
 
 void stmt_list_free(struct list_head *list)
diff --git a/src/utils.c b/src/utils.c
index e6ad8b8b..2aa1eb4e 100644
--- a/src/utils.c
+++ b/src/utils.c
@@ -24,11 +24,6 @@ void __noreturn __memory_allocation_error(const char *filename, uint32_t line)
 	exit(NFT_EXIT_NOMEM);
 }
 
-void xfree(const void *ptr)
-{
-	free((void *)ptr);
-}
-
 void *xmalloc(size_t size)
 {
 	void *ptr;
diff --git a/src/xt.c b/src/xt.c
index 48b2873b..f7bee216 100644
--- a/src/xt.c
+++ b/src/xt.c
@@ -78,7 +78,7 @@ void xt_stmt_xlate(const struct stmt *stmt, struct output_ctx *octx)
 
 			rc = mt->xlate(xl, &params);
 		}
-		xfree(m);
+		free(m);
 		break;
 	case NFT_XT_WATCHER:
 	case NFT_XT_TARGET:
@@ -108,14 +108,14 @@ void xt_stmt_xlate(const struct stmt *stmt, struct output_ctx *octx)
 
 			rc = tg->xlate(xl, &params);
 		}
-		xfree(t);
+		free(t);
 		break;
 	}
 
 	if (rc == 1)
 		nft_print(octx, "%s", xt_xlate_get(xl));
 	xt_xlate_free(xl);
-	xfree(entry);
+	free(entry);
 #endif
 	if (!rc)
 		nft_print(octx, "xt %s \"%s\"",
@@ -125,7 +125,7 @@ void xt_stmt_xlate(const struct stmt *stmt, struct output_ctx *octx)
 void xt_stmt_destroy(struct stmt *stmt)
 {
 	free_const(stmt->xt.name);
-	xfree(stmt->xt.info);
+	free(stmt->xt.info);
 }
 
 #ifdef HAVE_LIBXTABLES