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 34__BEGIN_DECLS 35 36typedef struct prop_info prop_info; 37 38#define PROP_NAME_MAX 32 39#define PROP_VALUE_MAX 92 40 41/* Look up a system property by name, copying its value and a 42** \0 terminator to the provided pointer. The total bytes 43** copied will be no greater than PROP_VALUE_MAX. Returns 44** the string length of the value. A property that is not 45** defined is identical to a property with a length 0 value. 46*/ 47int __system_property_get(const char *name, char *value); 48 49/* Set a system property by name. 50**/ 51int __system_property_set(const char *key, const char *value); 52 53/* Return a pointer to the system property named name, if it 54** exists, or NULL if there is no such property. Use 55** __system_property_read() to obtain the string value from 56** the returned prop_info pointer. 57** 58** It is safe to cache the prop_info pointer to avoid future 59** lookups. These returned pointers will remain valid for 60** the lifetime of the system. 61*/ 62const prop_info *__system_property_find(const char *name); 63 64/* Read the value of a system property. Returns the length 65** of the value. Copies the value and \0 terminator into 66** the provided value pointer. Total length (including 67** terminator) will be no greater that PROP_VALUE_MAX. 68** 69** If name is nonzero, up to PROP_NAME_MAX bytes will be 70** copied into the provided name pointer. The name will 71** be \0 terminated. 72*/ 73int __system_property_read(const prop_info *pi, char *name, char *value); 74 75/* Return a prop_info for the nth system property, or NULL if 76** there is no nth property. Use __system_property_read() to 77** read the value of this property. 78** 79** This method is for inspecting and debugging the property 80** system. Please use __system_property_find() instead. 81** 82** Order of results may change from call to call. This is 83** not a bug. 84*/ 85const prop_info *__system_property_find_nth(unsigned n); 86 87__END_DECLS 88 89#endif 90