1/*
2 * This file is part of ltrace.
3 * Copyright (C) 2011,2012 Petr Machata, Red Hat Inc.
4 *
5 * This program is free software; you can redistribute it and/or
6 * modify it under the terms of the GNU General Public License as
7 * published by the Free Software Foundation; either version 2 of the
8 * License, or (at your option) any later version.
9 *
10 * This program is distributed in the hope that it will be useful, but
11 * WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
13 * General Public License for more details.
14 *
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, write to the Free Software
17 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
18 * 02110-1301 USA
19 */
20
21#include <errno.h>
22
23#include "zero.h"
24#include "common.h"
25#include "type.h"
26#include "value.h"
27#include "expr.h"
28
29static int
30zero_callback_max(struct value *ret_value, struct value *lhs,
31		  struct value_dict *arguments,
32		  size_t max, void *data)
33{
34	size_t i;
35	for (i = 0; i < max; ++i) {
36		struct value element;
37		if (value_init_element(&element, lhs, i) < 0)
38			return -1;
39
40		int zero = value_is_zero(&element, arguments);
41
42		value_destroy(&element);
43
44		if (zero)
45			break;
46	}
47
48	struct arg_type_info *long_type = type_get_simple(ARGTYPE_LONG);
49	value_init_detached(ret_value, NULL, long_type, 0);
50	value_set_word(ret_value, i);
51	return 0;
52}
53
54/* LHS->zero(RHS).  Looks for a length of zero-terminated array, but
55 * looks no further than first RHS bytes.  */
56static int
57zero_callback(struct value *ret_value, struct value *lhs,
58	      struct value *rhs, struct value_dict *arguments, void *data)
59{
60	long l;
61	if (value_extract_word(rhs, &l, arguments) < 0)
62		return -1;
63	if (l < 0)
64		/* It might just be a positive value >2GB, but that's
65		 * not likely.  */
66		report_global_error("maximum array length seems negative");
67	size_t max = (size_t)l;
68	return zero_callback_max(ret_value, lhs, arguments, max, data);
69}
70
71/* LHS->zero.  Looks for a length of zero-terminated array, without
72 * limit.  */
73static int
74zero1_callback(struct value *ret_value, struct value *lhs,
75	       struct value_dict *arguments, void *data)
76{
77	return zero_callback_max(ret_value, lhs, arguments, (size_t)-1, data);
78}
79
80struct expr_node *
81build_zero_w_arg(struct expr_node *expr, int own)
82{
83	struct expr_node *e_z = malloc(sizeof(*e_z));
84	if (e_z == NULL)
85		return NULL;
86
87	expr_init_cb2(e_z, &zero_callback,
88		      expr_self(), 0, expr, own, NULL);
89	return e_z;
90}
91
92struct expr_node *
93expr_node_zero(void)
94{
95	static struct expr_node *nodep = NULL;
96	if (nodep == NULL) {
97		static struct expr_node node;
98		expr_init_cb1(&node, &zero1_callback,
99			      expr_self(), 0, (void *)-1);
100		nodep = &node;
101	}
102	return nodep;
103}
104