bionic/libc/include/sys/system_properties.h

86 lines
3.2 KiB
C

/*
* Copyright (C) 2008 The Android Open Source Project
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#ifndef _INCLUDE_SYS_SYSTEM_PROPERTIES_H
#define _INCLUDE_SYS_SYSTEM_PROPERTIES_H
#include <sys/cdefs.h>
__BEGIN_DECLS
typedef struct prop_info prop_info;
#define PROP_NAME_MAX 32
#define PROP_VALUE_MAX 92
/* Look up a system property by name, copying its value and a
** \0 terminator to the provided pointer. The total bytes
** copied will be no greater than PROP_VALUE_MAX. Returns
** the string length of the value. A property that is not
** defined is identical to a property with a length 0 value.
*/
int __system_property_get(const char *name, char *value);
/* Return a pointer to the system property named name, if it
** exists, or NULL if there is no such property. Use
** __system_property_read() to obtain the string value from
** the returned prop_info pointer.
**
** It is safe to cache the prop_info pointer to avoid future
** lookups. These returned pointers will remain valid for
** the lifetime of the system.
*/
const prop_info *__system_property_find(const char *name);
/* Read the value of a system property. Returns the length
** of the value. Copies the value and \0 terminator into
** the provided value pointer. Total length (including
** terminator) will be no greater that PROP_VALUE_MAX.
**
** If name is nonzero, up to PROP_NAME_MAX bytes will be
** copied into the provided name pointer. The name will
** be \0 terminated.
*/
int __system_property_read(const prop_info *pi, char *name, char *value);
/* Return a prop_info for the nth system property, or NULL if
** there is no nth property. Use __system_property_read() to
** read the value of this property.
**
** This method is for inspecting and debugging the property
** system. Please use __system_property_find() instead.
**
** Order of results may change from call to call. This is
** not a bug.
*/
const prop_info *__system_property_find_nth(unsigned n);
__END_DECLS
#endif