ipc_voucher.h   [plain text]

/*
 * Copyright (c) 2000-2004 Apple Computer, Inc. All rights reserved.
 *
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 * 
 * This file contains Original Code and/or Modifications of Original Code
 * as defined in and that are subject to the Apple Public Source License
 * Version 2.0 (the 'License'). You may not use this file except in
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 * may not be used to create, or enable the creation or redistribution of,
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 * 
 * Please obtain a copy of the License at
 * http://www.opensource.apple.com/apsl/ and read it before using this file.
 * 
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#ifndef	_IPC_IPC_VOUCHER_H_
#define	_IPC_IPC_VOUCHER_H_

#include <mach/mach_types.h>
#include <mach/mach_voucher_types.h>
#include <mach/boolean.h>
#include <ipc/ipc_types.h>

#ifdef MACH_KERNEL_PRIVATE

#include <kern/queue.h>
#include <kern/locks.h>
#include <kern/simple_lock.h>

/* locking */
extern lck_grp_t 	ipc_lck_grp;
extern lck_attr_t 	ipc_lck_attr;

extern void ipc_voucher_init(void);

/* some shorthand for longer types */
typedef mach_voucher_attr_value_handle_t        iv_value_handle_t;
typedef mach_voucher_attr_value_reference_t     iv_value_refs_t;

typedef natural_t		iv_refs_t;

typedef natural_t 		iv_index_t;
#define IV_UNUSED_VALINDEX	((iv_index_t) 0)
#define IV_UNUSED_KEYINDEX 	((iv_index_t) ~0)

typedef iv_index_t	 	*iv_entry_t;
#define IVE_NULL		((iv_entry_t) 0)

#define IV_ENTRIES_INLINE MACH_VOUCHER_ATTR_KEY_NUM_WELL_KNOWN

/*
 * IPC Voucher
 *
 * Vouchers are a reference counted immutable (once-created) set of
 * indexes to particular resource manager attribute values
 * (which themselves are reference counted).
 */
struct ipc_voucher {
	iv_index_t		iv_hash;	/* checksum hash */
	iv_index_t		iv_sum;		/* checksum of values */
	iv_refs_t		iv_refs;	/* reference count */
	iv_index_t		iv_table_size;	/* size of the voucher table */
	iv_index_t		iv_inline_table[IV_ENTRIES_INLINE];
	iv_entry_t		iv_table;	/* table of voucher attr entries */
	ipc_port_t		iv_port;	/* port representing the voucher */
	queue_chain_t		iv_hash_link;	/* link on hash chain */
};

#define IV_NULL 	IPC_VOUCHER_NULL


/*
 * Voucher Attribute Cache Control Object
 *
 * This is where the Voucher system stores its caches/references to
 * returned resource manager attribute values.  Each value only appears
 * once in the table.  If a value is returned more than once by the
 * resource manager, the voucher system will increase the reference
 * on the previous value.  
 *
 * The voucher itself contains one entry per key, that indexes into
 * this table.
 *
 * A voucher that does not have an explicit index for a given key
 * is assumed to have a reference on slot zero - which is where the
 * voucher system stores the default value for the given attribute
 * (specified at the time of resource manager registration).
 *
 * The ivace_releasing field limits the entry to a single concurrent
 * return. Without it, a previous release's reply might still be
 * working its way back to the voucher code, and a subsequent get-
 * value could return the same value as was previously returned.  If
 * the resource manager already knew that, it would return a failure
 * on the return, and all is well.  We just treat the additional made
 * references on the value as we normally would.  However, if the resource
 * manager accepted the return, and the get-value response raced the
 * release's reply, the newly made references will look like an extension
 * of the old value's cache lifetime, rather than a new one.  Dropping
 * that new lifetime's references to zero would result in a second 
 * release callback to the resource manager - this time with the wrong
 * "made" reference count.  We avoid the race with this flag.
 */

struct ivac_entry_s {
	iv_value_handle_t       ivace_value;
	iv_value_refs_t         ivace_layered:1,     /* layered effective entry */
	                        ivace_releasing:1,   /* release in progress */
				ivace_free:1,	     /* on freelist */
	                        ivace_refs:29;       /* reference count */
	union {
		iv_value_refs_t ivaceu_made;         /* made count (non-layered) */
		iv_index_t      ivaceu_layer;        /* next effective layer (layered) */
	} ivace_u;
	iv_index_t              ivace_next;          /* hash or freelist */
	iv_index_t              ivace_index;         /* hash head (independent) */
};
typedef struct ivac_entry_s       ivac_entry;
typedef ivac_entry              *ivac_entry_t;

#define ivace_made              ivace_u.ivaceu_made
#define ivace_layer             ivace_u.ivaceu_layer

#define IVACE_NULL              ((ivac_entry_t) 0);

#define IVACE_REFS_MAX          ((1 << 29) - 1)

#define IVAC_ENTRIES_MIN        512
#define IVAC_ENTRIES_MAX        524288

struct ipc_voucher_attr_control {
	iv_refs_t               ivac_refs;
	boolean_t               ivac_is_growing;	/* is the table being grown */
	ivac_entry_t            ivac_table;		/* table of voucher attr value entries */
	iv_index_t              ivac_table_size;	/* size of the attr value table */
	iv_index_t              ivac_init_table_size;	/* size of the attr value table */
	iv_index_t              ivac_freelist;  	/* index of the first free element */
	ipc_port_t              ivac_port;		/* port for accessing the cache control  */
	lck_spin_t              ivac_lock_data;
	iv_index_t              ivac_key_index;		/* key index for this value */
};
typedef ipc_voucher_attr_control_t iv_attr_control_t;

#define IVAC_NULL                  IPC_VOUCHER_ATTR_CONTROL_NULL

extern ipc_voucher_attr_control_t  ivac_alloc(iv_index_t);

#define ivac_lock_init(ivac) \
	lck_spin_init(&(ivac)->ivac_lock_data, &ipc_lck_grp, &ipc_lck_attr)
#define ivac_lock_destroy(ivac) \
	lck_spin_destroy(&(ivac)->ivac_lock_data, &ipc_lck_grp)
#define	ivac_lock(ivac) \
	lck_spin_lock(&(ivac)->ivac_lock_data)
#define	ivac_lock_try(ivac) \
	lck_spin_try_lock(&(ivac)->ivac_lock_data)
#define	ivac_unlock(ivac) \
	lck_spin_unlock(&(ivac)->ivac_lock_data)
#define ivac_sleep(ivac) lck_spin_sleep(&(ivac)->ivac_lock_data,	\
					LCK_SLEEP_DEFAULT,		\
					(event_t)(ivac),		\
					THREAD_UNINT)
#define ivac_wakeup(ivac) thread_wakeup((event_t)(ivac))

extern void ivac_dealloc(ipc_voucher_attr_control_t ivac);

static inline void
ivac_reference(ipc_voucher_attr_control_t ivac)
{
	(void)hw_atomic_add(&ivac->ivac_refs, 1);
}

static inline void
ivac_release(ipc_voucher_attr_control_t ivac)
{
	iv_refs_t refs;

	if (IVAC_NULL == ivac)
		return;

	refs = hw_atomic_sub(&ivac->ivac_refs, 1);
	if (refs == 0)
		ivac_dealloc(ivac);
}

#define IVAM_NULL IPC_VOUCHER_ATTR_MANAGER_NULL

/*
 * IPC voucher Resource Manager table element
 *
 * Information Associated with a specific registration of
 * a voucher resource manager.
 *
 * NOTE: For now, this table is indexed directly by the key.  In the future,
 * it will have to be growable and sparse by key.  When that is implemented
 * the index will be independent from the key (but there will be a hash to
 * find the index by key).
 */
typedef struct ipc_voucher_global_table_element {
	ipc_voucher_attr_manager_t	ivgte_manager;
	ipc_voucher_attr_control_t	ivgte_control;
	mach_voucher_attr_key_t		ivgte_key;
} ipc_voucher_global_table_element;

typedef ipc_voucher_global_table_element *ipc_voucher_global_table_element_t;

#endif /* MACH_KERNEL_PRIVATE */

/*
 * IPC voucher attribute recipe
 *
 * In-kernel recipe format with an ipc_voucher_t pointer for the previous
 * voucher reference.
 */
#pragma pack(1)
typedef struct ipc_voucher_attr_recipe_data {
	mach_voucher_attr_key_t	                key;
	mach_voucher_attr_recipe_command_t      command;
	ipc_voucher_t		                previous_voucher;
	mach_voucher_attr_content_size_t	content_size;
	uint8_t				        content[];
} ipc_voucher_attr_recipe_data_t;
typedef ipc_voucher_attr_recipe_data_t *ipc_voucher_attr_recipe_t;
typedef mach_msg_type_number_t ipc_voucher_attr_recipe_size_t;

typedef uint8_t *ipc_voucher_attr_raw_recipe_t;
typedef ipc_voucher_attr_raw_recipe_t ipc_voucher_attr_raw_recipe_array_t;
typedef mach_msg_type_number_t ipc_voucher_attr_raw_recipe_size_t;
typedef mach_msg_type_number_t ipc_voucher_attr_raw_recipe_array_size_t;

#pragma pack()

/*
 * In-kernel Resource Manager Definition
 *
 * In-kernel resource managers are defined by a v-table like structure for
 * the three callouts supported by a resource manager (and release function).
 *
 * There is a single in-kernel resource manager that represents all the
 * outside kernel managers (and reflects the calls through MIG to user-space).
 */

typedef kern_return_t (*ipc_voucher_attr_manager_release_value_t)(ipc_voucher_attr_manager_t,
								  mach_voucher_attr_key_t,
								  mach_voucher_attr_value_handle_t,
								  mach_voucher_attr_value_reference_t);

typedef kern_return_t (*ipc_voucher_attr_manager_get_value_t)(ipc_voucher_attr_manager_t,
							      mach_voucher_attr_key_t,
							      mach_voucher_attr_recipe_command_t,
							      mach_voucher_attr_value_handle_array_t,
							      mach_voucher_attr_value_handle_array_size_t,
							      mach_voucher_attr_content_t,
							      mach_voucher_attr_content_size_t,
							      mach_voucher_attr_value_handle_t *,
							      ipc_voucher_t *);

typedef kern_return_t (*ipc_voucher_attr_manager_extract_content_t)(ipc_voucher_attr_manager_t,
								    mach_voucher_attr_key_t,
								    mach_voucher_attr_value_handle_array_t,
								    mach_voucher_attr_value_handle_array_size_t,
								    mach_voucher_attr_recipe_command_t *,
								    mach_voucher_attr_content_t,
								    mach_voucher_attr_content_size_t *);

typedef kern_return_t (*ipc_voucher_attr_manager_command_t)(ipc_voucher_attr_manager_t,
							    mach_voucher_attr_key_t,
							    mach_voucher_attr_value_handle_array_t,
							    mach_voucher_attr_value_handle_array_size_t,
							    mach_voucher_attr_command_t,
							    mach_voucher_attr_content_t,
							    mach_voucher_attr_content_size_t,
							    mach_voucher_attr_content_t,
							    mach_voucher_attr_content_size_t *);

typedef void (*ipc_voucher_attr_manager_release_t)(ipc_voucher_attr_manager_t);

struct ipc_voucher_attr_manager {
	ipc_voucher_attr_manager_release_value_t	ivam_release_value;
	ipc_voucher_attr_manager_get_value_t		ivam_get_value;
	ipc_voucher_attr_manager_extract_content_t	ivam_extract_content;
	ipc_voucher_attr_manager_command_t		ivam_command;
	ipc_voucher_attr_manager_release_t		ivam_release;
};

__BEGIN_DECLS

/* DEBUG/TRACE Convert from a port to a voucher */
extern uintptr_t unsafe_convert_port_to_voucher(
	ipc_port_t		port);

/* Convert from a port to a voucher */
extern ipc_voucher_t convert_port_to_voucher(
	ipc_port_t		port);

/* Convert from a port name to an ipc_voucher */
extern ipc_voucher_t convert_port_name_to_voucher(
	mach_port_name_t	name);

/* add a reference to the specified voucher */
extern void ipc_voucher_reference(
	ipc_voucher_t		voucher);

/* drop the voucher reference picked up above */
extern void ipc_voucher_release(
	ipc_voucher_t		voucher);

/* deliver voucher notifications */
extern void ipc_voucher_notify(
	mach_msg_header_t 	*msg);

/* Convert from a voucher to a port */
extern ipc_port_t convert_voucher_to_port(
	ipc_voucher_t		voucher);

/* convert from a voucher attribute control to a port */
extern ipc_port_t convert_voucher_attr_control_to_port(
	ipc_voucher_attr_control_t	control);

/* add a reference to the specified voucher */
extern void ipc_voucher_attr_control_reference(
	ipc_voucher_attr_control_t	control);

/* drop the reference picked up above */
extern void ipc_voucher_attr_control_release(
	ipc_voucher_attr_control_t	control);

/* deliver voucher control notifications */
extern void ipc_voucher_attr_control_notify(
	mach_msg_header_t 	*msg);

/* convert from a port to a voucher attribute control */
extern ipc_voucher_attr_control_t convert_port_to_voucher_attr_control(
	ipc_port_t 		port);

/*
 * In-kernel equivalents to the user syscalls
 */
extern kern_return_t
ipc_create_mach_voucher(
	ipc_voucher_attr_raw_recipe_array_t	 	recipes,
	ipc_voucher_attr_raw_recipe_array_size_t	recipe_size,
	ipc_voucher_t 					*new_voucher);

extern kern_return_t
ipc_voucher_attr_control_create_mach_voucher(
	ipc_voucher_attr_control_t			control,
	ipc_voucher_attr_raw_recipe_array_t 		recipes,
	ipc_voucher_attr_raw_recipe_array_size_t	recipe_size,
	ipc_voucher_t 					*new_voucher);

extern kern_return_t 
ipc_register_well_known_mach_voucher_attr_manager(
	ipc_voucher_attr_manager_t 		manager,
	mach_voucher_attr_value_handle_t 	default_value,
        mach_voucher_attr_key_t 		key,
	ipc_voucher_attr_control_t 		*control);


extern kern_return_t
ipc_register_mach_voucher_attr_manager(
	ipc_voucher_attr_manager_t 		manager,
	mach_voucher_attr_value_handle_t 	default_value,
        mach_voucher_attr_key_t 		*key,
	ipc_voucher_attr_control_t 		*control);

__END_DECLS
					     
#endif	/* _IPC_IPC_VOUCHER_H_ */