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/*
* 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>
#ifndef _REALLY_INCLUDE_SYS__SYSTEM_PROPERTIES_H_
#error you should #include <sys/system_properties.h> instead
#else
#include <sys/system_properties.h>
typedef struct prop_msg prop_msg;
#define PROP_AREA_MAGIC 0x504f5250
#define PROP_AREA_VERSION 0xfc6ed0ab
#define PROP_AREA_VERSION_COMPAT 0x45434f76
#define PROP_SERVICE_NAME "property_service"
#define PROP_FILENAME_MAX 1024
#define PROP_FILENAME "/dev/__properties__"
#define PA_SIZE (128 * 1024)
#define SERIAL_VALUE_LEN(serial) ((serial) >> 24)
#define SERIAL_DIRTY(serial) ((serial) & 1)
__BEGIN_DECLS
struct prop_msg
{
unsigned cmd;
char name[PROP_NAME_MAX];
char value[PROP_VALUE_MAX];
};
#define PROP_MSG_SETPROP 1
/*
** Rules:
**
** - there is only one writer, but many readers
** - prop_area.count will never decrease in value
** - once allocated, a prop_info's name will not change
** - once allocated, a prop_info's offset will not change
** - reading a value requires the following steps
** 1. serial = pi->serial
** 2. if SERIAL_DIRTY(serial), wait*, then goto 1
** 3. memcpy(local, pi->value, SERIAL_VALUE_LEN(serial) + 1)
** 4. if pi->serial != serial, goto 2
**
** - writing a value requires the following steps
** 1. pi->serial = pi->serial | 1
** 2. memcpy(pi->value, local_value, value_len)
** 3. pi->serial = (value_len << 24) | ((pi->serial + 1) & 0xffffff)
*/
#define PROP_PATH_RAMDISK_DEFAULT "/default.prop"
#define PROP_PATH_SYSTEM_BUILD "/system/build.prop"
#define PROP_PATH_VENDOR_BUILD "/vendor/build.prop"
#define PROP_PATH_LOCAL_OVERRIDE "/data/local.prop"
#define PROP_PATH_FACTORY "/factory/factory.prop"
/*
** Map the property area from the specified filename. This
** method is for testing only.
*/
int __system_property_set_filename(const char *filename);
/*
** Initialize the area to be used to store properties. Can
** only be done by a single process that has write access to
** the property area.
*/
int __system_property_area_init();
/* Read the global serial number of the system properties
**
** Called to predict if a series of cached __system_property_find
** objects will have seen __system_property_serial values change.
** But also aids the converse, as changes in the global serial can
** also be used to predict if a failed __system_property_find
** could in-turn now find a new object; thus preventing the
** cycles of effort to poll __system_property_find.
**
** Typically called at beginning of a cache cycle to signal if _any_ possible
** changes have occurred since last. If there is, one may check each individual
** __system_property_serial to confirm dirty, or __system_property_find
** to check if the property now exists. If a call to __system_property_add
** or __system_property_update has completed between two calls to
** __system_property_area_serial then the second call will return a larger
** value than the first call. Beware of race conditions as changes to the
** properties are not atomic, the main value of this call is to determine
** whether the expensive __system_property_find is worth retrying to see if
** a property now exists.
**
** Returns the serial number on success, -1 on error.
*/
unsigned int __system_property_area_serial();
/* Add a new system property. Can only be done by a single
** process that has write access to the property area, and
** that process must handle sequencing to ensure the property
** does not already exist and that only one property is added
** or updated at a time.
**
** Returns 0 on success, -1 if the property area is full.
*/
int __system_property_add(const char *name, unsigned int namelen,
const char *value, unsigned int valuelen);
/* Update the value of a system property returned by
** __system_property_find. Can only be done by a single process
** that has write access to the property area, and that process
** must handle sequencing to ensure that only one property is
** updated at a time.
**
** Returns 0 on success, -1 if the parameters are incorrect.
*/
int __system_property_update(prop_info *pi, const char *value, unsigned int len);
/* Read the serial number of a system property returned by
** __system_property_find.
**
** Returns the serial number on success, -1 on error.
*/
unsigned int __system_property_serial(const prop_info *pi);
/* Wait for any system property to be updated. Caller must pass
** in 0 the first time, and the previous return value on each
** successive call. */
unsigned int __system_property_wait_any(unsigned int serial);
/* Compatibility functions to support using an old init with a new libc,
** mostly for the OTA updater binary. These can be deleted once OTAs from
** a pre-K release no longer needed to be supported. */
const prop_info *__system_property_find_compat(const char *name);
int __system_property_read_compat(const prop_info *pi, char *name, char *value);
int __system_property_foreach_compat(
void (*propfn)(const prop_info *pi, void *cookie),
void *cookie);
/* Initialize the system properties area in read only mode.
* Should be done by all processes that need to read system
* properties.
*
* Returns 0 on success, -1 otherwise.
*/
int __system_properties_init();
__END_DECLS
#endif
#endif
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