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
26 extern "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 */
46 int property_get(const char* key, char* value, const char* default_value);
47
48 /* property_get_bool: returns the value of key coerced into a
49 ** boolean. If the property is not set, then the default value is returned.
50 **
51 * The following is considered to be true (1):
52 ** "1", "true", "y", "yes", "on"
53 **
54 ** The following is considered to be false (0):
55 ** "0", "false", "n", "no", "off"
56 **
57 ** The conversion is whitespace-sensitive (e.g. " off" will not be false).
58 **
59 ** If no property with this key is set (or the key is NULL) or the boolean
60 ** conversion fails, the default value is returned.
61 **/
62 int8_t property_get_bool(const char *key, int8_t default_value);
63
64 /* property_get_int64: returns the value of key truncated and coerced into a
65 ** int64_t. If the property is not set, then the default value is used.
66 **
67 ** The numeric conversion is identical to strtoimax with the base inferred:
68 ** - All digits up to the first non-digit characters are read
69 ** - The longest consecutive prefix of digits is converted to a long
70 **
71 ** Valid strings of digits are:
72 ** - An optional sign character + or -
73 ** - An optional prefix indicating the base (otherwise base 10 is assumed)
74 ** -- 0 prefix is octal
75 ** -- 0x / 0X prefix is hex
76 **
77 ** Leading/trailing whitespace is ignored. Overflow/underflow will cause
78 ** numeric conversion to fail.
79 **
80 ** If no property with this key is set (or the key is NULL) or the numeric
81 ** conversion fails, the default value is returned.
82 **/
83 int64_t property_get_int64(const char *key, int64_t default_value);
84
85 /* property_get_int32: returns the value of key truncated and coerced into an
86 ** int32_t. If the property is not set, then the default value is used.
87 **
88 ** The numeric conversion is identical to strtoimax with the base inferred:
89 ** - All digits up to the first non-digit characters are read
90 ** - The longest consecutive prefix of digits is converted to a long
91 **
92 ** Valid strings of digits are:
93 ** - An optional sign character + or -
94 ** - An optional prefix indicating the base (otherwise base 10 is assumed)
95 ** -- 0 prefix is octal
96 ** -- 0x / 0X prefix is hex
97 **
98 ** Leading/trailing whitespace is ignored. Overflow/underflow will cause
99 ** numeric conversion to fail.
100 **
101 ** If no property with this key is set (or the key is NULL) or the numeric
102 ** conversion fails, the default value is returned.
103 **/
104 int32_t property_get_int32(const char *key, int32_t default_value);
105
106 /* property_set: returns 0 on success, < 0 on failure
107 */
108 int property_set(const char *key, const char *value);
109
110 int property_list(void (*propfn)(const char *key, const char *value, void *cookie), void *cookie);
111
112 #if defined(__BIONIC_FORTIFY)
113 #define __property_get_err_str "property_get() called with too small of a buffer"
114
115 #if defined(__clang__)
116
117 /* Some projects use -Weverything; diagnose_if is clang-specific. */
118 #pragma clang diagnostic push
119 #pragma clang diagnostic ignored "-Wgcc-compat"
120 int property_get(const char* key, char* value, const char* default_value)
121 __clang_error_if(__bos(value) != __BIONIC_FORTIFY_UNKNOWN_SIZE &&
122 __bos(value) < PROPERTY_VALUE_MAX,
123 __property_get_err_str);
124 #pragma clang diagnostic pop
125
126 #else /* defined(__clang__) */
127
128 extern int __property_get_real(const char *, char *, const char *)
129 __asm__(__USER_LABEL_PREFIX__ "property_get");
130 __errordecl(__property_get_too_small_error, __property_get_err_str);
131
132 __BIONIC_FORTIFY_INLINE
property_get(const char * key,char * value,const char * default_value)133 int property_get(const char *key, char *value, const char *default_value) {
134 size_t bos = __bos(value);
135 if (bos < PROPERTY_VALUE_MAX) {
136 __property_get_too_small_error();
137 }
138 return __property_get_real(key, value, default_value);
139 }
140
141 #endif /* defined(__clang__) */
142
143 #undef __property_get_err_str
144 #endif /* defined(__BIONIC_FORTIFY) */
145
146 #ifdef __cplusplus
147 }
148 #endif
149
150 #endif
151