1/*
2 * Copyright (C) 2006 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17#ifndef __CUTILS_PROPERTIES_H
18#define __CUTILS_PROPERTIES_H
19
20#include <sys/cdefs.h>
21#include <stddef.h>
22#include <sys/system_properties.h>
23#include <stdint.h>
24
25#ifdef __cplusplus
26extern "C" {
27#endif
28
29/* System properties are *small* name value pairs managed by the
30** property service.  If your data doesn't fit in the provided
31** space it is not appropriate for a system property.
32**
33** WARNING: system/bionic/include/sys/system_properties.h also defines
34**          these, but with different names.  (TODO: fix that)
35*/
36#define PROPERTY_KEY_MAX   PROP_NAME_MAX
37#define PROPERTY_VALUE_MAX  PROP_VALUE_MAX
38
39/* property_get: returns the length of the value which will never be
40** greater than PROPERTY_VALUE_MAX - 1 and will always be zero terminated.
41** (the length does not include the terminating zero).
42**
43** If the property read fails or returns an empty value, the default
44** value is used (if nonnull).
45*/
46int property_get(const char *key, char *value, const char *default_value)
47/* Sometimes we use not-Bionic with this, so we need this check. */
48#if defined(__BIONIC_FORTIFY)
49        __overloadable __RENAME_CLANG(property_get)
50#endif
51        ;
52
53/* property_get_bool: returns the value of key coerced into a
54** boolean. If the property is not set, then the default value is returned.
55**
56* The following is considered to be true (1):
57**   "1", "true", "y", "yes", "on"
58**
59** The following is considered to be false (0):
60**   "0", "false", "n", "no", "off"
61**
62** The conversion is whitespace-sensitive (e.g. " off" will not be false).
63**
64** If no property with this key is set (or the key is NULL) or the boolean
65** conversion fails, the default value is returned.
66**/
67int8_t property_get_bool(const char *key, int8_t default_value);
68
69/* property_get_int64: returns the value of key truncated and coerced into a
70** int64_t. If the property is not set, then the default value is used.
71**
72** The numeric conversion is identical to strtoimax with the base inferred:
73** - All digits up to the first non-digit characters are read
74** - The longest consecutive prefix of digits is converted to a long
75**
76** Valid strings of digits are:
77** - An optional sign character + or -
78** - An optional prefix indicating the base (otherwise base 10 is assumed)
79**   -- 0 prefix is octal
80**   -- 0x / 0X prefix is hex
81**
82** Leading/trailing whitespace is ignored. Overflow/underflow will cause
83** numeric conversion to fail.
84**
85** If no property with this key is set (or the key is NULL) or the numeric
86** conversion fails, the default value is returned.
87**/
88int64_t property_get_int64(const char *key, int64_t default_value);
89
90/* property_get_int32: returns the value of key truncated and coerced into an
91** int32_t. If the property is not set, then the default value is used.
92**
93** The numeric conversion is identical to strtoimax with the base inferred:
94** - All digits up to the first non-digit characters are read
95** - The longest consecutive prefix of digits is converted to a long
96**
97** Valid strings of digits are:
98** - An optional sign character + or -
99** - An optional prefix indicating the base (otherwise base 10 is assumed)
100**   -- 0 prefix is octal
101**   -- 0x / 0X prefix is hex
102**
103** Leading/trailing whitespace is ignored. Overflow/underflow will cause
104** numeric conversion to fail.
105**
106** If no property with this key is set (or the key is NULL) or the numeric
107** conversion fails, the default value is returned.
108**/
109int32_t property_get_int32(const char *key, int32_t default_value);
110
111/* property_set: returns 0 on success, < 0 on failure
112*/
113int property_set(const char *key, const char *value);
114
115int property_list(void (*propfn)(const char *key, const char *value, void *cookie), void *cookie);
116
117#if defined(__BIONIC_FORTIFY)
118#define __property_get_err_str "property_get() called with too small of a buffer"
119
120#if defined(__clang__)
121
122/* Some projects use -Weverything; enable_if is clang-specific.
123** FIXME: This is marked used because we'll otherwise get complaints about an
124** unused static function. This is more robust than marking it unused, since
125** -Wused-but-marked-unused is a thing that will complain if this function is
126** actually used, thus making FORTIFY noisier when an error happens. It's going
127** to go away anyway during our FORTIFY cleanup.
128**/
129#pragma clang diagnostic push
130#pragma clang diagnostic ignored "-Wgcc-compat"
131__BIONIC_ERROR_FUNCTION_VISIBILITY
132int property_get(const char *key, char *value, const char *default_value)
133        __overloadable
134        __enable_if(__bos(value) != __BIONIC_FORTIFY_UNKNOWN_SIZE &&
135                    __bos(value) < PROPERTY_VALUE_MAX, __property_get_err_str)
136        __errorattr(__property_get_err_str)
137        __attribute__((used));
138#pragma clang diagnostic pop
139
140/* No object size? No FORTIFY.
141*/
142
143#else /* defined(__clang__) */
144
145extern int __property_get_real(const char *, char *, const char *)
146    __asm__(__USER_LABEL_PREFIX__ "property_get");
147__errordecl(__property_get_too_small_error, __property_get_err_str);
148
149__BIONIC_FORTIFY_INLINE
150int property_get(const char *key, char *value, const char *default_value) {
151    size_t bos = __bos(value);
152    if (bos < PROPERTY_VALUE_MAX) {
153        __property_get_too_small_error();
154    }
155    return __property_get_real(key, value, default_value);
156}
157
158#endif /* defined(__clang__) */
159
160#undef __property_get_err_str
161#endif /* defined(__BIONIC_FORTIFY) */
162
163#ifdef __cplusplus
164}
165#endif
166
167#endif
168