libc/include/sys/_system_properties.h - platform/bionic - Git at Google


            
            /*

            
             * 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


            #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
	/*
	* 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

	#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