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 /* 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 **/
67 int8_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 **/
88 int64_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 **/
109 int32_t property_get_int32(const char *key, int32_t default_value);
110
111 /* property_set: returns 0 on success, < 0 on failure
112 */
113 int property_set(const char *key, const char *value);
114
115 int 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
132 int 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
145 extern 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
property_get(const char * key,char * value,const char * default_value)150 int 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