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#ifndef _REALLY_INCLUDE_SYS__SYSTEM_PROPERTIES_H_ 33#error you should #include <sys/system_properties.h> instead 34#else 35#include <sys/system_properties.h> 36 37typedef struct prop_msg prop_msg; 38 39#define PROP_AREA_MAGIC 0x504f5250 40#define PROP_AREA_VERSION 0xfc6ed0ab 41#define PROP_AREA_VERSION_COMPAT 0x45434f76 42 43#define PROP_SERVICE_NAME "property_service" 44#define PROP_FILENAME "/dev/__properties__" 45 46#define PA_SIZE (128 * 1024) 47 48#define SERIAL_VALUE_LEN(serial) ((serial) >> 24) 49#define SERIAL_DIRTY(serial) ((serial) & 1) 50 51__BEGIN_DECLS 52 53struct prop_msg 54{ 55 unsigned cmd; 56 char name[PROP_NAME_MAX]; 57 char value[PROP_VALUE_MAX]; 58}; 59 60#define PROP_MSG_SETPROP 1 61 62/* 63** Rules: 64** 65** - there is only one writer, but many readers 66** - prop_area.count will never decrease in value 67** - once allocated, a prop_info's name will not change 68** - once allocated, a prop_info's offset will not change 69** - reading a value requires the following steps 70** 1. serial = pi->serial 71** 2. if SERIAL_DIRTY(serial), wait*, then goto 1 72** 3. memcpy(local, pi->value, SERIAL_VALUE_LEN(serial) + 1) 73** 4. if pi->serial != serial, goto 2 74** 75** - writing a value requires the following steps 76** 1. pi->serial = pi->serial | 1 77** 2. memcpy(pi->value, local_value, value_len) 78** 3. pi->serial = (value_len << 24) | ((pi->serial + 1) & 0xffffff) 79*/ 80 81#define PROP_PATH_RAMDISK_DEFAULT "/default.prop" 82#define PROP_PATH_SYSTEM_BUILD "/system/build.prop" 83#define PROP_PATH_SYSTEM_DEFAULT "/system/default.prop" 84#define PROP_PATH_LOCAL_OVERRIDE "/data/local.prop" 85#define PROP_PATH_FACTORY "/factory/factory.prop" 86 87/* 88** Map the property area from the specified filename. This 89** method is for testing only. 90*/ 91int __system_property_set_filename(const char *filename); 92 93/* 94** Initialize the area to be used to store properties. Can 95** only be done by a single process that has write access to 96** the property area. 97*/ 98int __system_property_area_init(); 99 100/* Add a new system property. Can only be done by a single 101** process that has write access to the property area, and 102** that process must handle sequencing to ensure the property 103** does not already exist and that only one property is added 104** or updated at a time. 105** 106** Returns 0 on success, -1 if the property area is full. 107*/ 108int __system_property_add(const char *name, unsigned int namelen, 109 const char *value, unsigned int valuelen); 110 111/* Update the value of a system property returned by 112** __system_property_find. Can only be done by a single process 113** that has write access to the property area, and that process 114** must handle sequencing to ensure that only one property is 115** updated at a time. 116** 117** Returns 0 on success, -1 if the parameters are incorrect. 118*/ 119int __system_property_update(prop_info *pi, const char *value, unsigned int len); 120 121/* Read the serial number of a system property returned by 122** __system_property_find. 123** 124** Returns the serial number on success, -1 on error. 125*/ 126unsigned int __system_property_serial(const prop_info *pi); 127 128/* Wait for any system property to be updated. Caller must pass 129** in 0 the first time, and the previous return value on each 130** successive call. */ 131unsigned int __system_property_wait_any(unsigned int serial); 132 133/* Compatibility functions to support using an old init with a new libc, 134 ** mostly for the OTA updater binary. These can be deleted once OTAs from 135 ** a pre-K release no longer needed to be supported. */ 136const prop_info *__system_property_find_compat(const char *name); 137int __system_property_read_compat(const prop_info *pi, char *name, char *value); 138int __system_property_foreach_compat( 139 void (*propfn)(const prop_info *pi, void *cookie), 140 void *cookie); 141 142__END_DECLS 143 144#endif 145#endif 146