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
29 static int
zero_callback_max(struct value * ret_value,struct value * lhs,struct value_dict * arguments,size_t max,void * data)30 zero_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. */
56 static int
zero_callback(struct value * ret_value,struct value * lhs,struct value * rhs,struct value_dict * arguments,void * data)57 zero_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. */
73 static int
zero1_callback(struct value * ret_value,struct value * lhs,struct value_dict * arguments,void * data)74 zero1_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
80 struct expr_node *
build_zero_w_arg(struct expr_node * expr,int own)81 build_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
92 struct expr_node *
expr_node_zero(void)93 expr_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