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 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
