[apple/xnu.git] / osfmk / ipc / ipc_space.c

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/*
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/* 
 * Mach Operating System
 * Copyright (c) 1991,1990,1989 Carnegie Mellon University
 * All Rights Reserved.
 * 
 * Permission to use, copy, modify and distribute this software and its
 * documentation is hereby granted, provided that both the copyright
 * notice and this permission notice appear in all copies of the
 * software, derivative works or modified versions, and any portions
 * thereof, and that both notices appear in supporting documentation.
 * 
 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
 * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
 * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
 * 
 * Carnegie Mellon requests users of this software to return to
 * 
 *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
 *  School of Computer Science
 *  Carnegie Mellon University
 *  Pittsburgh PA 15213-3890
 * 
 * any improvements or extensions that they make and grant Carnegie Mellon
 * the rights to redistribute these changes.
 */
/*
 */
/*
 *      File:   ipc/ipc_space.c
 *      Author: Rich Draves
 *      Date:   1989
 *
 *      Functions to manipulate IPC capability spaces.
 */

#include <mach_kdb.h>

#include <mach/boolean.h>
#include <mach/kern_return.h>
#include <mach/port.h>
#include <kern/assert.h>
#include <kern/sched_prim.h>
#include <kern/zalloc.h>
#include <ipc/port.h>
#include <ipc/ipc_entry.h>
#include <ipc/ipc_splay.h>
#include <ipc/ipc_object.h>
#include <ipc/ipc_hash.h>
#include <ipc/ipc_table.h>
#include <ipc/ipc_port.h>
#include <ipc/ipc_space.h>
#include <ipc/ipc_right.h>
#include <string.h>

zone_t ipc_space_zone;
ipc_space_t ipc_space_kernel;
ipc_space_t ipc_space_reply;
#if     MACH_KDB
ipc_space_t default_pager_space;
#endif  /* MACH_KDB */

/*
 *      Routine:        ipc_space_reference
 *      Routine:        ipc_space_release
 *      Purpose:
 *              Function versions of the IPC space macros.
 *              The "is_" cover macros can be defined to use the
 *              macros or the functions, as desired.
 */

void
ipc_space_reference(
        ipc_space_t     space)
{
        ipc_space_reference_macro(space);
}

void
ipc_space_release(
        ipc_space_t     space)
{
        ipc_space_release_macro(space);
}

/*
 *      Routine:        ipc_space_create
 *      Purpose:
 *              Creates a new IPC space.
 *
 *              The new space has two references, one for the caller
 *              and one because it is active.
 *      Conditions:
 *              Nothing locked.  Allocates memory.
 *      Returns:
 *              KERN_SUCCESS            Created a space.
 *              KERN_RESOURCE_SHORTAGE  Couldn't allocate memory.
 */

kern_return_t
ipc_space_create(
        ipc_table_size_t        initial,
        ipc_space_t             *spacep)
{
        ipc_space_t space;
        ipc_entry_t table;
        ipc_entry_num_t new_size;
        mach_port_index_t index;

        space = is_alloc();
        if (space == IS_NULL)
                return KERN_RESOURCE_SHORTAGE;

        table = it_entries_alloc(initial);
        if (table == IE_NULL) {
                is_free(space);
                return KERN_RESOURCE_SHORTAGE;
        }

        new_size = initial->its_size;
        memset((void *) table, 0, new_size * sizeof(struct ipc_entry));

        /*
         *      Initialize the free list in the table.
         *      Add the entries in reverse order, and
         *      set the generation number to -1, so that
         *      initial allocations produce "natural" names.
         */
        for (index = 0; index < new_size; index++) {
                ipc_entry_t entry = &table[index];

                entry->ie_bits = IE_BITS_GEN_MASK;
                entry->ie_next = index+1;
        }
        table[new_size-1].ie_next = 0;

        is_ref_lock_init(space);
        space->is_references = 2;

        is_lock_init(space);
        space->is_active = TRUE;
        space->is_growing = FALSE;
        space->is_table = table;
        space->is_table_size = new_size;
        space->is_table_next = initial+1;

        ipc_splay_tree_init(&space->is_tree);
        space->is_tree_total = 0;
        space->is_tree_small = 0;
        space->is_tree_hash = 0;

        *spacep = space;
        return KERN_SUCCESS;
}

/*
 *      Routine:        ipc_space_create_special
 *      Purpose:
 *              Create a special space.  A special space
 *              doesn't hold rights in the normal way.
 *              Instead it is place-holder for holding
 *              disembodied (naked) receive rights.
 *              See ipc_port_alloc_special/ipc_port_dealloc_special.
 *      Conditions:
 *              Nothing locked.
 *      Returns:
 *              KERN_SUCCESS            Created a space.
 *              KERN_RESOURCE_SHORTAGE  Couldn't allocate memory.
 */

kern_return_t
ipc_space_create_special(
        ipc_space_t     *spacep)
{
        ipc_space_t space;

        space = is_alloc();
        if (space == IS_NULL)
                return KERN_RESOURCE_SHORTAGE;

        is_ref_lock_init(space);
        space->is_references = 1;

        is_lock_init(space);
        space->is_active = FALSE;

        *spacep = space;
        return KERN_SUCCESS;
}

/*
 * ipc_space_clean - remove all port references from an ipc space.
 *
 * In order to follow the traditional semantic, ipc_space_destroy
 * will not destroy the entire port table of a shared space.  Instead
 * it will simply clear its own sub-space.
 */
void
ipc_space_clean(
        ipc_space_t space)
{
        ipc_tree_entry_t tentry;
        ipc_entry_t table;
        ipc_entry_num_t size;
        mach_port_index_t index;

        /*
         *      If somebody is trying to grow the table,
         *      we must wait until they finish and figure
         *      out the space died.
         */
        is_write_lock(space);
        while (space->is_growing)
                is_write_sleep(space);

        /*
         *      Now we can futz with it since we have the write lock.
         */
#if     MACH_KDB
        if (space == default_pager_space)
                default_pager_space = IS_NULL;
#endif  /* MACH_KDB */

        table = space->is_table;
        size = space->is_table_size;

        for (index = 0; index < size; index++) {
                ipc_entry_t entry = &table[index];
                mach_port_type_t type;

                type = IE_BITS_TYPE(entry->ie_bits);
                if (type != MACH_PORT_TYPE_NONE) {
                        mach_port_name_t name = MACH_PORT_MAKE(index,
                                                IE_BITS_GEN(entry->ie_bits));
                        ipc_right_destroy(space, name, entry);
                }
        }

        /*
         * JMM - Now the table is cleaned out.  We don't bother shrinking the
         * size of the table at this point, but we probably should if it is
         * really large.  Lets just clean up the splay tree.
         */
 start_splay:
        for (tentry = ipc_splay_traverse_start(&space->is_tree);
             tentry != ITE_NULL;
             tentry = ipc_splay_traverse_next(&space->is_tree, TRUE)) {
                mach_port_type_t type;
                mach_port_name_t name = tentry->ite_name;

                type = IE_BITS_TYPE(tentry->ite_bits);
                /*
                 * If it is a real right, then destroy it.  This will have the
                 * side effect of removing it from the splay, so start over.
                 */
                if(type != MACH_PORT_TYPE_NONE) {
                        ipc_splay_traverse_finish(&space->is_tree);
                        ipc_right_destroy(space, name, &tentry->ite_entry);
                        goto start_splay;
                }
        }
        ipc_splay_traverse_finish(&space->is_tree);
        is_write_unlock(space);
}


/*
 *      Routine:        ipc_space_destroy
 *      Purpose:
 *              Marks the space as dead and cleans up the entries.
 *              Does nothing if the space is already dead.
 *      Conditions:
 *              Nothing locked.
 */

void
ipc_space_destroy(
        ipc_space_t     space)
{
        boolean_t active;
        ipc_tree_entry_t tentry;
        ipc_entry_t table;
        ipc_entry_num_t size;
        mach_port_index_t index;

        assert(space != IS_NULL);

        is_write_lock(space);
        active = space->is_active;
        space->is_active = FALSE;
        is_write_unlock(space);

        if (!active)
                return;


        /*
         *      If somebody is trying to grow the table,
         *      we must wait until they finish and figure
         *      out the space died.
         */
        is_read_lock(space);
        while (space->is_growing)
                is_read_sleep(space);

        is_read_unlock(space);
        /*
         *      Now we can futz with it unlocked.
         */
#if     MACH_KDB
        if (space == default_pager_space)
                default_pager_space = IS_NULL;
#endif  /* MACH_KDB */

        table = space->is_table;
        size = space->is_table_size;

        for (index = 0; index < size; index++) {
                ipc_entry_t entry = &table[index];
                mach_port_type_t type;

                type = IE_BITS_TYPE(entry->ie_bits);
                if (type != MACH_PORT_TYPE_NONE) {
                        mach_port_name_t name;

                        name = MACH_PORT_MAKE(index,
                                              IE_BITS_GEN(entry->ie_bits));
                        ipc_right_clean(space, name, entry);
                }
        }

        it_entries_free(space->is_table_next-1, table);
        space->is_table_size = 0;

        for (tentry = ipc_splay_traverse_start(&space->is_tree);
             tentry != ITE_NULL;
             tentry = ipc_splay_traverse_next(&space->is_tree, TRUE)) {
                mach_port_type_t type;
                mach_port_name_t name = tentry->ite_name;

                type = IE_BITS_TYPE(tentry->ite_bits);
                assert(type != MACH_PORT_TYPE_NONE);

                ipc_right_clean(space, name, &tentry->ite_entry);

                if(type == MACH_PORT_TYPE_SEND)
                        ipc_hash_global_delete(space, tentry->ite_object,
                                               name, tentry);
        }
        ipc_splay_traverse_finish(&space->is_tree);

        /*
         *      Because the space is now dead,
         *      we must release the "active" reference for it.
         *      Our caller still has his reference.
         */
        is_release(space);
}