1 /* 2 * Copyright (C) 2008 The Android Open Source Project 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * * Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * * Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in 12 * the documentation and/or other materials provided with the 13 * distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 16 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 17 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 18 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE 19 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 21 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS 22 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 23 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 24 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT 25 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26 * SUCH DAMAGE. 27 */ 28 29 #ifndef _INCLUDE_SYS__SYSTEM_PROPERTIES_H 30 #define _INCLUDE_SYS__SYSTEM_PROPERTIES_H 31 32 #include <sys/cdefs.h> 33 #include <stdint.h> 34 35 #ifndef _REALLY_INCLUDE_SYS__SYSTEM_PROPERTIES_H_ 36 #error you should #include <sys/system_properties.h> instead 37 #endif 38 39 #include <sys/system_properties.h> 40 41 __BEGIN_DECLS 42 43 #define PROP_SERVICE_NAME "property_service" 44 #define PROP_SERVICE_FOR_SYSTEM_NAME "property_service_for_system" 45 #define PROP_DIRNAME "/dev/__properties__" 46 47 #define PROP_MSG_SETPROP 1 48 #define PROP_MSG_SETPROP2 0x00020001 49 50 #define PROP_SUCCESS 0 51 #define PROP_ERROR_READ_CMD 0x0004 52 #define PROP_ERROR_READ_DATA 0x0008 53 #define PROP_ERROR_READ_ONLY_PROPERTY 0x000B 54 #define PROP_ERROR_INVALID_NAME 0x0010 55 #define PROP_ERROR_INVALID_VALUE 0x0014 56 #define PROP_ERROR_PERMISSION_DENIED 0x0018 57 #define PROP_ERROR_INVALID_CMD 0x001B 58 #define PROP_ERROR_HANDLE_CONTROL_MESSAGE 0x0020 59 #define PROP_ERROR_SET_FAILED 0x0024 60 61 /* 62 ** This was previously for testing, but now that SystemProperties is its own testable class, 63 ** there is never a reason to call this function and its implementation simply returns -1. 64 */ 65 int __system_property_set_filename(const char* __unused __filename); 66 67 /* 68 ** Initialize the area to be used to store properties. Can 69 ** only be done by a single process that has write access to 70 ** the property area. 71 */ 72 int __system_property_area_init(void); 73 74 /* Read the global serial number of the system properties 75 ** 76 ** Called to predict if a series of cached __system_property_find 77 ** objects will have seen __system_property_serial values change. 78 ** But also aids the converse, as changes in the global serial can 79 ** also be used to predict if a failed __system_property_find 80 ** could in-turn now find a new object; thus preventing the 81 ** cycles of effort to poll __system_property_find. 82 ** 83 ** Typically called at beginning of a cache cycle to signal if _any_ possible 84 ** changes have occurred since last. If there is, one may check each individual 85 ** __system_property_serial to confirm dirty, or __system_property_find 86 ** to check if the property now exists. If a call to __system_property_add 87 ** or __system_property_update has completed between two calls to 88 ** __system_property_area_serial then the second call will return a larger 89 ** value than the first call. Beware of race conditions as changes to the 90 ** properties are not atomic, the main value of this call is to determine 91 ** whether the expensive __system_property_find is worth retrying to see if 92 ** a property now exists. 93 ** 94 ** Returns the serial number on success, -1 on error. 95 */ 96 uint32_t __system_property_area_serial(void); 97 98 /* Add a new system property. Can only be done by a single 99 ** process that has write access to the property area, and 100 ** that process must handle sequencing to ensure the property 101 ** does not already exist and that only one property is added 102 ** or updated at a time. 103 ** 104 ** Returns 0 on success, -1 if the property area is full. 105 */ 106 int __system_property_add(const char* _Nonnull __name, unsigned int __name_length, const char* _Nonnull __value, unsigned int __value_length); 107 108 /* Update the value of a system property returned by 109 ** __system_property_find. Can only be done by a single process 110 ** that has write access to the property area, and that process 111 ** must handle sequencing to ensure that only one property is 112 ** updated at a time. 113 ** 114 ** Returns 0 on success, -1 if the parameters are incorrect. 115 */ 116 int __system_property_update(prop_info* _Nonnull __pi, const char* _Nonnull __value, unsigned int __value_length); 117 118 /* Read the serial number of a system property returned by 119 ** __system_property_find. 120 ** 121 ** Returns the serial number on success, -1 on error. 122 */ 123 uint32_t __system_property_serial(const prop_info* _Nonnull __pi); 124 125 /* Initialize the system properties area in read only mode. 126 * Should be done by all processes that need to read system 127 * properties. 128 * 129 * Returns 0 on success, -1 otherwise. 130 */ 131 int __system_properties_init(void); 132 133 /* 134 * Reloads the system properties from disk. 135 * Not intended for use by any apps except the Zygote. Should only be called from the main thread. 136 * 137 * NOTE: Any pointers received from methods such as __system_property_find should be assumed to be 138 * invalid after this method is called. 139 * 140 * Returns 0 on success, -1 if the system properties failed to re-initialize (same conditions as 141 * __system properties_init) 142 */ 143 int __system_properties_zygote_reload(void) __INTRODUCED_IN(__ANDROID_API_V__); 144 145 /* Deprecated: use __system_property_wait instead. */ 146 uint32_t __system_property_wait_any(uint32_t __old_serial); 147 148 __END_DECLS 149 150 #endif 151