lens_enum.c revision 1f075e5ba076d5f818723387464a8d013ff7b9fe 
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 <stdlib.h>
22#include <assert.h>
23#include <string.h>
24
25#include "lens_enum.h"
26#include "lens_default.h"
27#include "value.h"
28#include "sysdep.h"
29#include "type.h"
30
31struct enum_entry {
32	char *key;
33	int own_key;
34	struct value *value;
35	int own_value;
36};
37
38static void
39enum_entry_dtor(struct enum_entry *entry, void *data)
40{
41	if (entry->own_key)
42		free(entry->key);
43	if (entry->own_value) {
44		value_destroy(entry->value);
45		free(entry->value);
46	}
47}
48
49static void
50enum_lens_destroy_cb(struct lens *lens)
51{
52	struct enum_lens *self = (void *)lens;
53
54	VECT_DESTROY(&self->entries, struct enum_entry,
55		     enum_entry_dtor, NULL);
56}
57
58enum {
59#ifdef ARCH_ENDIAN_BIG
60	big_endian = 1,
61#elif defined (ARCH_ENDIAN_LITTLE)
62	big_endian = 0,
63#else
64# error Undefined endianness.
65#endif
66};
67
68/* Returns 0 if they are not equal, >0 if they are, and <0 if there
69 * was an error.  */
70static int
71enum_values_equal(struct value *inf_value, struct value *enum_value,
72		  struct value_dict *arguments)
73{
74	/* Width may not match between what's defined in config file
75	 * and what arrives from the back end.  Typically, if there is
76	 * a mismatch, the config file size will be larger, as we are
77	 * in a situation where 64-bit tracer traces 32-bit process.
78	 * But opposite situation can occur e.g. on PPC, where it's
79	 * apparently possible for 32-bit tracer to trace 64-bit
80	 * inferior, or hypothetically in a x32/x86_64 situation.  */
81
82	unsigned char *inf_data = value_get_data(inf_value, arguments);
83	size_t inf_sz = value_size(inf_value, arguments);
84	if (inf_data == NULL || inf_sz == (size_t)-1)
85		return -1;
86
87	assert(inf_value->type->type == enum_value->type->type);
88
89	unsigned char *enum_data = value_get_data(enum_value, arguments);
90	size_t enum_sz = value_size(enum_value, arguments);
91	if (enum_data == NULL || enum_sz == (size_t)-1)
92		return -1;
93
94	size_t sz = enum_sz > inf_sz ? inf_sz : enum_sz;
95
96	if (big_endian)
97		return memcmp(enum_data + enum_sz - sz,
98			      inf_data + inf_sz - sz, sz) == 0;
99	else
100		return memcmp(enum_data, inf_data, sz) == 0;
101}
102
103static const char *
104enum_get(struct enum_lens *lens, struct value *value,
105	 struct value_dict *arguments)
106{
107	size_t i;
108	for (i = 0; i < vect_size(&lens->entries); ++i) {
109		struct enum_entry *entry = VECT_ELEMENT(&lens->entries,
110							struct enum_entry, i);
111		int st = enum_values_equal(value, entry->value, arguments);
112		if (st < 0)
113			return NULL;
114		else if (st != 0)
115			return entry->key;
116	}
117	return NULL;
118}
119
120static int
121enum_lens_format_cb(struct lens *lens, FILE *stream,
122		    struct value *value, struct value_dict *arguments)
123{
124	struct enum_lens *self = (void *)lens;
125
126	const char *name = enum_get(self, value, arguments);
127	if (name != NULL)
128		return fprintf(stream, "%s", name);
129
130	return lens_format(&default_lens, stream, value, arguments);
131}
132
133
134void
135lens_init_enum(struct enum_lens *lens)
136{
137	*lens = (struct enum_lens){
138		{
139			.format_cb = enum_lens_format_cb,
140			.destroy_cb = enum_lens_destroy_cb,
141		},
142	};
143	VECT_INIT(&lens->entries, struct enum_entry);
144}
145
146int
147lens_enum_add(struct enum_lens *lens,
148	      const char *key, int own_key,
149	      struct value *value, int own_value)
150{
151	struct enum_entry entry = { (char *)key, own_key, value, own_value };
152	return VECT_PUSHBACK(&lens->entries, &entry);
153}
154
155size_t
156lens_enum_size(struct enum_lens *lens)
157{
158	return vect_size(&lens->entries);
159}
160