xnu-2050.24.15.tar.gz

[apple/xnu.git] / bsd / kern / ubc_subr.c

/*
 * Copyright (c) 1999-2008 Apple Inc. All rights reserved.
 *
 * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
 * 
 * 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
 * compliance with the License. The rights granted to you under the License
 * may not be used to create, or enable the creation or redistribution of,
 * unlawful or unlicensed copies of an Apple operating system, or to
 * circumvent, violate, or enable the circumvention or violation of, any
 * terms of an Apple operating system software license agreement.
 * 
 * Please obtain a copy of the License at
 * http://www.opensource.apple.com/apsl/ and read it before using this file.
 * 
 * The Original Code and all software distributed under the License are
 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
 * Please see the License for the specific language governing rights and
 * limitations under the License.
 * 
 * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
 */
/* 
 *      File:   ubc_subr.c
 *      Author: Umesh Vaishampayan [umeshv@apple.com]
 *              05-Aug-1999     umeshv  Created.
 *
 *      Functions related to Unified Buffer cache.
 *
 * Caller of UBC functions MUST have a valid reference on the vnode.
 *
 */ 

#include <sys/types.h>
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/lock.h>
#include <sys/mman.h>
#include <sys/mount_internal.h>
#include <sys/vnode_internal.h>
#include <sys/ubc_internal.h>
#include <sys/ucred.h>
#include <sys/proc_internal.h>
#include <sys/kauth.h>
#include <sys/buf.h>
#include <sys/user.h>
#include <sys/codesign.h>

#include <mach/mach_types.h>
#include <mach/memory_object_types.h>
#include <mach/memory_object_control.h>
#include <mach/vm_map.h>
#include <mach/mach_vm.h>
#include <mach/upl.h>

#include <kern/kern_types.h>
#include <kern/kalloc.h>
#include <kern/zalloc.h>
#include <kern/thread.h>
#include <vm/vm_kern.h>
#include <vm/vm_protos.h> /* last */

#include <libkern/crypto/sha1.h>

#include <security/mac_framework.h>

/* XXX These should be in a BSD accessible Mach header, but aren't. */
extern kern_return_t memory_object_pages_resident(memory_object_control_t,
                                                        boolean_t *);
extern kern_return_t    memory_object_signed(memory_object_control_t control,
                                             boolean_t is_signed);
extern boolean_t        memory_object_is_slid(memory_object_control_t   control);

extern void Debugger(const char *message);


/* XXX no one uses this interface! */
kern_return_t ubc_page_op_with_control(
        memory_object_control_t  control,
        off_t                    f_offset,
        int                      ops,
        ppnum_t                  *phys_entryp,
        int                      *flagsp);


#if DIAGNOSTIC
#if defined(assert)
#undef assert
#endif
#define assert(cond)    \
    ((void) ((cond) ? 0 : panic("Assert failed: %s", # cond)))
#else
#include <kern/assert.h>
#endif /* DIAGNOSTIC */

static int ubc_info_init_internal(struct vnode *vp, int withfsize, off_t filesize);
static int ubc_umcallback(vnode_t, void *);
static int ubc_msync_internal(vnode_t, off_t, off_t, off_t *, int, int *);
static void ubc_cs_free(struct ubc_info *uip);

struct zone     *ubc_info_zone;


/*
 * CODESIGNING
 * Routines to navigate code signing data structures in the kernel...
 */

extern int cs_debug;

static boolean_t
cs_valid_range(
        const void *start,
        const void *end,
        const void *lower_bound,
        const void *upper_bound)
{
        if (upper_bound < lower_bound ||
            end < start) {
                return FALSE;
        }

        if (start < lower_bound ||
            end > upper_bound) {
                return FALSE;
        }

        return TRUE;
}

/*
 * Magic numbers used by Code Signing
 */
enum {
        CSMAGIC_REQUIREMENT = 0xfade0c00,               /* single Requirement blob */
        CSMAGIC_REQUIREMENTS = 0xfade0c01,              /* Requirements vector (internal requirements) */
        CSMAGIC_CODEDIRECTORY = 0xfade0c02,             /* CodeDirectory blob */
        CSMAGIC_EMBEDDED_SIGNATURE = 0xfade0cc0, /* embedded form of signature data */
        CSMAGIC_EMBEDDED_SIGNATURE_OLD = 0xfade0b02,    /* XXX */
        CSMAGIC_EMBEDDED_ENTITLEMENTS = 0xfade7171,     /* embedded entitlements */
        CSMAGIC_DETACHED_SIGNATURE = 0xfade0cc1, /* multi-arch collection of embedded signatures */
        
        CSSLOT_CODEDIRECTORY = 0,                               /* slot index for CodeDirectory */
        CSSLOT_ENTITLEMENTS = 5
};

static const uint32_t supportsScatter = 0x20100;        // first version to support scatter option

/*
 * Structure of an embedded-signature SuperBlob
 */
typedef struct __BlobIndex {
        uint32_t type;                                  /* type of entry */
        uint32_t offset;                                /* offset of entry */
} CS_BlobIndex;

typedef struct __SuperBlob {
        uint32_t magic;                                 /* magic number */
        uint32_t length;                                /* total length of SuperBlob */
        uint32_t count;                                 /* number of index entries following */
        CS_BlobIndex index[];                   /* (count) entries */
        /* followed by Blobs in no particular order as indicated by offsets in index */
} CS_SuperBlob;

typedef struct __GenericBlob {
        uint32_t magic;                         /* magic number */
        uint32_t length;                        /* total length of blob */
        char data[];
} CS_GenericBlob;

struct Scatter {
        uint32_t count;                 // number of pages; zero for sentinel (only)
        uint32_t base;                  // first page number
        uint64_t targetOffset;          // offset in target
        uint64_t spare;                 // reserved
};

/*
 * C form of a CodeDirectory.
 */
typedef struct __CodeDirectory {
        uint32_t magic;                                 /* magic number (CSMAGIC_CODEDIRECTORY) */
        uint32_t length;                                /* total length of CodeDirectory blob */
        uint32_t version;                               /* compatibility version */
        uint32_t flags;                                 /* setup and mode flags */
        uint32_t hashOffset;                    /* offset of hash slot element at index zero */
        uint32_t identOffset;                   /* offset of identifier string */
        uint32_t nSpecialSlots;                 /* number of special hash slots */
        uint32_t nCodeSlots;                    /* number of ordinary (code) hash slots */
        uint32_t codeLimit;                             /* limit to main image signature range */
        uint8_t hashSize;                               /* size of each hash in bytes */
        uint8_t hashType;                               /* type of hash (cdHashType* constants) */
        uint8_t spare1;                                 /* unused (must be zero) */
        uint8_t pageSize;                               /* log2(page size in bytes); 0 => infinite */
        uint32_t spare2;                                /* unused (must be zero) */
        /* Version 0x20100 */
        uint32_t scatterOffset;                         /* offset of optional scatter vector */
        /* followed by dynamic content as located by offset fields above */
} CS_CodeDirectory;


/*
 * Locate the CodeDirectory from an embedded signature blob
 */
static const 
CS_CodeDirectory *findCodeDirectory(
        const CS_SuperBlob *embedded,
        char *lower_bound,
        char *upper_bound)
{
        const CS_CodeDirectory *cd = NULL;

        if (embedded &&
            cs_valid_range(embedded, embedded + 1, lower_bound, upper_bound) &&
            ntohl(embedded->magic) == CSMAGIC_EMBEDDED_SIGNATURE) {
                const CS_BlobIndex *limit;
                const CS_BlobIndex *p;

                limit = &embedded->index[ntohl(embedded->count)];
                if (!cs_valid_range(&embedded->index[0], limit,
                                    lower_bound, upper_bound)) {
                        return NULL;
                }
                for (p = embedded->index; p < limit; ++p) {
                        if (ntohl(p->type) == CSSLOT_CODEDIRECTORY) {
                                const unsigned char *base;

                                base = (const unsigned char *)embedded;
                                cd = (const CS_CodeDirectory *)(base + ntohl(p->offset));
                                break;
                        }
                }
        } else {
                /*
                 * Detached signatures come as a bare CS_CodeDirectory,
                 * without a blob.
                 */
                cd = (const CS_CodeDirectory *) embedded;
        }

        if (cd &&
            cs_valid_range(cd, cd + 1, lower_bound, upper_bound) &&
            cs_valid_range(cd, (const char *) cd + ntohl(cd->length),
                           lower_bound, upper_bound) &&
            cs_valid_range(cd, (const char *) cd + ntohl(cd->hashOffset),
                           lower_bound, upper_bound) &&
            cs_valid_range(cd, (const char *) cd +
                           ntohl(cd->hashOffset) +
                           (ntohl(cd->nCodeSlots) * SHA1_RESULTLEN),
                           lower_bound, upper_bound) &&
            
            ntohl(cd->magic) == CSMAGIC_CODEDIRECTORY) {
                return cd;
        }

        // not found or not a valid code directory
        return NULL;
}


/*
 * Locating a page hash
 */
static const unsigned char *
hashes(
        const CS_CodeDirectory *cd,
        unsigned page,
        char *lower_bound,
        char *upper_bound)
{
        const unsigned char *base, *top, *hash;
        uint32_t nCodeSlots = ntohl(cd->nCodeSlots);

        assert(cs_valid_range(cd, cd + 1, lower_bound, upper_bound));

        if((ntohl(cd->version) >= supportsScatter) && (ntohl(cd->scatterOffset))) {
                /* Get first scatter struct */
                const struct Scatter *scatter = (const struct Scatter*)
                        ((const char*)cd + ntohl(cd->scatterOffset));
                uint32_t hashindex=0, scount, sbase=0;
                /* iterate all scatter structs */
                do {
                        if((const char*)scatter > (const char*)cd + ntohl(cd->length)) {
                                if(cs_debug) {
                                        printf("CODE SIGNING: Scatter extends past Code Directory\n");
                                }
                                return NULL;
                        }
                        
                        scount = ntohl(scatter->count);
                        uint32_t new_base = ntohl(scatter->base);

                        /* last scatter? */
                        if (scount == 0) {
                                return NULL;
                        }
                        
                        if((hashindex > 0) && (new_base <= sbase)) {
                                if(cs_debug) {
                                        printf("CODE SIGNING: unordered Scatter, prev base %d, cur base %d\n",
                                        sbase, new_base);
                                }
                                return NULL;    /* unordered scatter array */
                        }
                        sbase = new_base;

                        /* this scatter beyond page we're looking for? */
                        if (sbase > page) {
                                return NULL;
                        }
                        
                        if (sbase+scount >= page) {
                                /* Found the scatter struct that is 
                                 * referencing our page */

                                /* base = address of first hash covered by scatter */
                                base = (const unsigned char *)cd + ntohl(cd->hashOffset) + 
                                        hashindex * SHA1_RESULTLEN;
                                /* top = address of first hash after this scatter */
                                top = base + scount * SHA1_RESULTLEN;
                                if (!cs_valid_range(base, top, lower_bound, 
                                                    upper_bound) ||
                                    hashindex > nCodeSlots) {
                                        return NULL;
                                }
                                
                                break;
                        }
                        
                        /* this scatter struct is before the page we're looking 
                         * for. Iterate. */
                        hashindex+=scount;
                        scatter++;
                } while(1);
                
                hash = base + (page - sbase) * SHA1_RESULTLEN;
        } else {
                base = (const unsigned char *)cd + ntohl(cd->hashOffset);
                top = base + nCodeSlots * SHA1_RESULTLEN;
                if (!cs_valid_range(base, top, lower_bound, upper_bound) ||
                    page > nCodeSlots) {
                        return NULL;
                }
                assert(page < nCodeSlots);

                hash = base + page * SHA1_RESULTLEN;
        }
        
        if (!cs_valid_range(hash, hash + SHA1_RESULTLEN,
                            lower_bound, upper_bound)) {
                hash = NULL;
        }

        return hash;
}
/*
 * CODESIGNING
 * End of routines to navigate code signing data structures in the kernel.
 */

/*
 * ENTITLEMENTS
 * Routines to navigate entitlements in the kernel.
 */

/* Retrieve the entitlements blob for a process.
 * Returns:
 *   EINVAL     no text vnode associated with the process
 *   EBADEXEC   invalid code signing data
 *   ENOMEM     you should reboot
 *   0          no error occurred
 *
 * On success, out_start and out_length will point to the
 * entitlements blob if found; or will be set to NULL/zero
 * if there were no entitlements.
 */
int
cs_entitlements_blob_get(proc_t p, void **out_start, size_t *out_length)
{
        SHA1_CTX context;                       /* XXX hash agility */
        int error = 0;
        struct cs_blob *blob_list_entry;
        CS_SuperBlob *super_blob;
        CS_BlobIndex *blob_index;
        CS_GenericBlob *blob;
        CS_CodeDirectory *code_dir;
        unsigned char *computed_hash = NULL;
        unsigned char *embedded_hash = NULL;
        void *start = NULL;
        size_t length = 0;
        size_t hash_size = 0;
        unsigned int i, count;

        if (NULL == p->p_textvp) {
                error = EINVAL;
                goto out;
        }
        if (NULL == (blob_list_entry = ubc_cs_blob_get(p->p_textvp, -1,
            p->p_textoff)))
                goto out;
        super_blob = (void *)blob_list_entry->csb_mem_kaddr;
        if (CSMAGIC_EMBEDDED_SIGNATURE != ntohl(super_blob->magic)) {
                error = EBADEXEC;
                goto out;
        }
        count = ntohl(super_blob->count);
        for (i = 0; i < count; ++i) {
                blob_index = &super_blob->index[i];
                blob = (void *)((char *)super_blob + ntohl(blob_index->offset));
                switch (ntohl(blob_index->type)) {
                case CSSLOT_CODEDIRECTORY:
                        if (CSMAGIC_CODEDIRECTORY != ntohl(blob->magic))
                                break;
                        code_dir = (void *)blob;
                        hash_size = code_dir->hashSize;
                        if (CSSLOT_ENTITLEMENTS <=
                            ntohl(code_dir->nSpecialSlots)) {
                                embedded_hash = (void *)((char *)code_dir +
                                    ntohl(code_dir->hashOffset) -
                                    (hash_size * CSSLOT_ENTITLEMENTS));
                        }
                        break;
                case CSSLOT_ENTITLEMENTS:
                        if (CSMAGIC_EMBEDDED_ENTITLEMENTS != ntohl(blob->magic))
                                break;
                        start = (void *)blob;
                        length = ntohl(blob->length);
                        break;
                default:
                        break;
                }
        }
        if (NULL == start && NULL == embedded_hash) {
                error = 0;
                goto out;
        } else if (NULL == start || NULL == embedded_hash) {
                error = EBADEXEC;
                goto out;
        }
        if (NULL == (computed_hash = kalloc(hash_size))) {
                error = ENOMEM;
                goto out;
        }
        SHA1Init(&context);
        SHA1Update(&context, start, length);
        SHA1Final(computed_hash, &context);
        if (0 != memcmp(computed_hash, embedded_hash, hash_size)) {
                error = EBADEXEC;
                goto out;
        }
        error = 0;
out:
        if (NULL != computed_hash)
                kfree(computed_hash, hash_size);
        if (0 == error) {
                *out_start = start;
                *out_length = length;
        }
        return error;
}

/*
 * ENTITLEMENTS
 * End of routines to navigate entitlements in the kernel.
 */



/*
 * ubc_init
 * 
 * Initialization of the zone for Unified Buffer Cache.
 *
 * Parameters:  (void)
 *
 * Returns:     (void)
 *
 * Implicit returns:
 *              ubc_info_zone(global)   initialized for subsequent allocations
 */
__private_extern__ void
ubc_init(void)
{
        int     i;

        i = (vm_size_t) sizeof (struct ubc_info);

        ubc_info_zone = zinit (i, 10000*i, 8192, "ubc_info zone");

        zone_change(ubc_info_zone, Z_NOENCRYPT, TRUE);
}


/*
 * ubc_info_init
 *
 * Allocate and attach an empty ubc_info structure to a vnode
 *
 * Parameters:  vp                      Pointer to the vnode
 *
 * Returns:     0                       Success
 *      vnode_size:ENOMEM               Not enough space
 *      vnode_size:???                  Other error from vnode_getattr
 *
 */
int
ubc_info_init(struct vnode *vp)
{
        return(ubc_info_init_internal(vp, 0, 0));
}


/*
 * ubc_info_init_withsize
 *
 * Allocate and attach a sized ubc_info structure to a vnode
 *
 * Parameters:  vp                      Pointer to the vnode
 *              filesize                The size of the file
 *
 * Returns:     0                       Success
 *      vnode_size:ENOMEM               Not enough space
 *      vnode_size:???                  Other error from vnode_getattr
 */
int
ubc_info_init_withsize(struct vnode *vp, off_t filesize)
{
        return(ubc_info_init_internal(vp, 1, filesize));
}


/*
 * ubc_info_init_internal
 *
 * Allocate and attach a ubc_info structure to a vnode
 *
 * Parameters:  vp                      Pointer to the vnode
 *              withfsize{0,1}          Zero if the size should be obtained
 *                                      from the vnode; otherwise, use filesize
 *              filesize                The size of the file, if withfsize == 1
 *
 * Returns:     0                       Success
 *      vnode_size:ENOMEM               Not enough space
 *      vnode_size:???                  Other error from vnode_getattr
 *
 * Notes:       We call a blocking zalloc(), and the zone was created as an
 *              expandable and collectable zone, so if no memory is available,
 *              it is possible for zalloc() to block indefinitely.  zalloc()
 *              may also panic if the zone of zones is exhausted, since it's
 *              NOT expandable.
 *
 *              We unconditionally call vnode_pager_setup(), even if this is
 *              a reuse of a ubc_info; in that case, we should probably assert
 *              that it does not already have a pager association, but do not.
 *
 *              Since memory_object_create_named() can only fail from receiving
 *              an invalid pager argument, the explicit check and panic is
 *              merely precautionary.
 */
static int
ubc_info_init_internal(vnode_t vp, int withfsize, off_t filesize)
{
        register struct ubc_info        *uip;
        void *  pager;
        int error = 0;
        kern_return_t kret;
        memory_object_control_t control;

        uip = vp->v_ubcinfo;

        /*
         * If there is not already a ubc_info attached to the vnode, we
         * attach one; otherwise, we will reuse the one that's there.
         */
        if (uip == UBC_INFO_NULL) {

                uip = (struct ubc_info *) zalloc(ubc_info_zone);
                bzero((char *)uip, sizeof(struct ubc_info));

                uip->ui_vnode = vp;
                uip->ui_flags = UI_INITED;
                uip->ui_ucred = NOCRED;
        }
        assert(uip->ui_flags != UI_NONE);
        assert(uip->ui_vnode == vp);

        /* now set this ubc_info in the vnode */
        vp->v_ubcinfo = uip;

        /*
         * Allocate a pager object for this vnode
         *
         * XXX The value of the pager parameter is currently ignored.
         * XXX Presumably, this API changed to avoid the race between
         * XXX setting the pager and the UI_HASPAGER flag.
         */
        pager = (void *)vnode_pager_setup(vp, uip->ui_pager);
        assert(pager);

        /*
         * Explicitly set the pager into the ubc_info, after setting the
         * UI_HASPAGER flag.
         */
        SET(uip->ui_flags, UI_HASPAGER);
        uip->ui_pager = pager;

        /*
         * Note: We can not use VNOP_GETATTR() to get accurate
         * value of ui_size because this may be an NFS vnode, and
         * nfs_getattr() can call vinvalbuf(); if this happens,
         * ubc_info is not set up to deal with that event.
         * So use bogus size.
         */

        /*
         * create a vnode - vm_object association
         * memory_object_create_named() creates a "named" reference on the
         * memory object we hold this reference as long as the vnode is
         * "alive."  Since memory_object_create_named() took its own reference
         * on the vnode pager we passed it, we can drop the reference
         * vnode_pager_setup() returned here.
         */
        kret = memory_object_create_named(pager,
                (memory_object_size_t)uip->ui_size, &control);
        vnode_pager_deallocate(pager); 
        if (kret != KERN_SUCCESS)
                panic("ubc_info_init: memory_object_create_named returned %d", kret);

        assert(control);
        uip->ui_control = control;      /* cache the value of the mo control */
        SET(uip->ui_flags, UI_HASOBJREF);       /* with a named reference */

        if (withfsize == 0) {
                /* initialize the size */
                error = vnode_size(vp, &uip->ui_size, vfs_context_current());
                if (error)
                        uip->ui_size = 0;
        } else {
                uip->ui_size = filesize;
        }
        vp->v_lflag |= VNAMED_UBC;      /* vnode has a named ubc reference */

        return (error);
}


/*
 * ubc_info_free
 *
 * Free a ubc_info structure
 *
 * Parameters:  uip                     A pointer to the ubc_info to free
 *
 * Returns:     (void)
 *
 * Notes:       If there is a credential that has subsequently been associated
 *              with the ubc_info via a call to ubc_setcred(), the reference
 *              to the credential is dropped.
 *
 *              It's actually impossible for a ubc_info.ui_control to take the
 *              value MEMORY_OBJECT_CONTROL_NULL.
 */
static void
ubc_info_free(struct ubc_info *uip)
{
        if (IS_VALID_CRED(uip->ui_ucred)) {
                kauth_cred_unref(&uip->ui_ucred);
        }

        if (uip->ui_control != MEMORY_OBJECT_CONTROL_NULL)
                memory_object_control_deallocate(uip->ui_control);
        
        cluster_release(uip);
        ubc_cs_free(uip);

        zfree(ubc_info_zone, uip);
        return;
}


void
ubc_info_deallocate(struct ubc_info *uip)
{
        ubc_info_free(uip);
}


/*
 * ubc_setsize
 *
 * Tell the  VM that the the size of the file represented by the vnode has
 * changed
 *
 * Parameters:  vp                      The vp whose backing file size is
 *                                      being changed
 *              nsize                   The new size of the backing file
 *
 * Returns:     1                       Success
 *              0                       Failure
 *
 * Notes:       This function will indicate failure if the new size that's
 *              being attempted to be set is negative.
 *
 *              This function will fail if there is no ubc_info currently
 *              associated with the vnode.
 *
 *              This function will indicate success it the new size is the
 *              same or larger than the old size (in this case, the remainder
 *              of the file will require modification or use of an existing upl
 *              to access successfully).
 *
 *              This function will fail if the new file size is smaller, and
 *              the memory region being invalidated was unable to actually be
 *              invalidated and/or the last page could not be flushed, if the
 *              new size is not aligned to a page boundary.  This is usually
 *              indicative of an I/O error.
 */
int
ubc_setsize(struct vnode *vp, off_t nsize)
{
        off_t osize;    /* ui_size before change */
        off_t lastpg, olastpgend, lastoff;
        struct ubc_info *uip;
        memory_object_control_t control;
        kern_return_t kret = KERN_SUCCESS;

        if (nsize < (off_t)0)
                return (0);

        if (!UBCINFOEXISTS(vp))
                return (0);

        uip = vp->v_ubcinfo;
        osize = uip->ui_size;
        /*
         * Update the size before flushing the VM
         */
        uip->ui_size = nsize;

        if (nsize >= osize) {   /* Nothing more to do */
                if (nsize > osize) {
                        lock_vnode_and_post(vp, NOTE_EXTEND);
                }

                return (1);             /* return success */
        }

        /*
         * When the file shrinks, invalidate the pages beyond the
         * new size. Also get rid of garbage beyond nsize on the
         * last page. The ui_size already has the nsize, so any
         * subsequent page-in will zero-fill the tail properly
         */
        lastpg = trunc_page_64(nsize);
        olastpgend = round_page_64(osize);
        control = uip->ui_control;
        assert(control);
        lastoff = (nsize & PAGE_MASK_64);

        if (lastoff) {
                upl_t           upl;
                upl_page_info_t *pl;


                /*
                 * new EOF ends up in the middle of a page
                 * zero the tail of this page if its currently
                 * present in the cache
                 */
                kret = ubc_create_upl(vp, lastpg, PAGE_SIZE, &upl, &pl, UPL_SET_LITE);
                
                if (kret != KERN_SUCCESS)
                        panic("ubc_setsize: ubc_create_upl (error = %d)\n", kret);

                if (upl_valid_page(pl, 0))
                        cluster_zero(upl, (uint32_t)lastoff, PAGE_SIZE - (uint32_t)lastoff, NULL);

                ubc_upl_abort_range(upl, 0, PAGE_SIZE, UPL_ABORT_FREE_ON_EMPTY);

                lastpg += PAGE_SIZE_64;
        }
        if (olastpgend > lastpg) {
                int     flags;

                if (lastpg == 0)
                        flags = MEMORY_OBJECT_DATA_FLUSH_ALL;
                else
                        flags = MEMORY_OBJECT_DATA_FLUSH;
                /*
                 * invalidate the pages beyond the new EOF page
                 *
                 */
                kret = memory_object_lock_request(control,
                                                  (memory_object_offset_t)lastpg,
                                                  (memory_object_size_t)(olastpgend - lastpg), NULL, NULL,
                                                  MEMORY_OBJECT_RETURN_NONE, flags, VM_PROT_NO_CHANGE);
                if (kret != KERN_SUCCESS)
                        printf("ubc_setsize: invalidate failed (error = %d)\n", kret);
        }
        return ((kret == KERN_SUCCESS) ? 1 : 0);
}


/*
 * ubc_getsize
 *
 * Get the size of the file assocated with the specified vnode
 *
 * Parameters:  vp                      The vnode whose size is of interest
 *
 * Returns:     0                       There is no ubc_info associated with
 *                                      this vnode, or the size is zero
 *              !0                      The size of the file
 *
 * Notes:       Using this routine, it is not possible for a caller to
 *              successfully distinguish between a vnode associate with a zero
 *              length file, and a vnode with no associated ubc_info.  The
 *              caller therefore needs to not care, or needs to ensure that
 *              they have previously successfully called ubc_info_init() or
 *              ubc_info_init_withsize().
 */
off_t
ubc_getsize(struct vnode *vp)
{
        /* people depend on the side effect of this working this way
         * as they call this for directory 
         */
        if (!UBCINFOEXISTS(vp))
                return ((off_t)0);
        return (vp->v_ubcinfo->ui_size);
}


/*
 * ubc_umount
 *
 * Call ubc_sync_range(vp, 0, EOF, UBC_PUSHALL) on all the vnodes for this
 * mount point
 *
 * Parameters:  mp                      The mount point
 *
 * Returns:     0                       Success
 *
 * Notes:       There is no failure indication for this function.
 *
 *              This function is used in the unmount path; since it may block
 *              I/O indefinitely, it should not be used in the forced unmount
 *              path, since a device unavailability could also block that
 *              indefinitely.
 *
 *              Because there is no device ejection interlock on USB, FireWire,
 *              or similar devices, it's possible that an ejection that begins
 *              subsequent to the vnode_iterate() completing, either on one of
 *              those devices, or a network mount for which the server quits
 *              responding, etc., may cause the caller to block indefinitely.
 */
__private_extern__ int
ubc_umount(struct mount *mp)
{
        vnode_iterate(mp, 0, ubc_umcallback, 0);
        return(0);
}


/*
 * ubc_umcallback
 *
 * Used by ubc_umount() as an internal implementation detail; see ubc_umount()
 * and vnode_iterate() for details of implementation.
 */
static int
ubc_umcallback(vnode_t vp, __unused void * args)
{

        if (UBCINFOEXISTS(vp)) {

                (void) ubc_msync(vp, (off_t)0, ubc_getsize(vp), NULL, UBC_PUSHALL);
        }
        return (VNODE_RETURNED);
}


/*
 * ubc_getcred
 *
 * Get the credentials currently active for the ubc_info associated with the
 * vnode.
 *
 * Parameters:  vp                      The vnode whose ubc_info credentials
 *                                      are to be retrieved
 *
 * Returns:     !NOCRED                 The credentials
 *              NOCRED                  If there is no ubc_info for the vnode,
 *                                      or if there is one, but it has not had
 *                                      any credentials associated with it via
 *                                      a call to ubc_setcred()
 */
kauth_cred_t
ubc_getcred(struct vnode *vp)
{
        if (UBCINFOEXISTS(vp))
                return (vp->v_ubcinfo->ui_ucred);

        return (NOCRED);
}


/*
 * ubc_setthreadcred
 *
 * If they are not already set, set the credentials of the ubc_info structure
 * associated with the vnode to those of the supplied thread; otherwise leave
 * them alone.
 *
 * Parameters:  vp                      The vnode whose ubc_info creds are to
 *                                      be set
 *              p                       The process whose credentials are to
 *                                      be used, if not running on an assumed
 *                                      credential
 *              thread                  The thread whose credentials are to
 *                                      be used
 *
 * Returns:     1                       This vnode has no associated ubc_info
 *              0                       Success
 *
 * Notes:       This function takes a proc parameter to account for bootstrap
 *              issues where a task or thread may call this routine, either
 *              before credentials have been initialized by bsd_init(), or if
 *              there is no BSD info asscoiate with a mach thread yet.  This
 *              is known to happen in both the initial swap and memory mapping
 *              calls.
 *
 *              This function is generally used only in the following cases:
 *
 *              o       a memory mapped file via the mmap() system call
 *              o       a memory mapped file via the deprecated map_fd() call
 *              o       a swap store backing file
 *              o       subsequent to a successful write via vn_write()
 *
 *              The information is then used by the NFS client in order to
 *              cons up a wire message in either the page-in or page-out path.
 *
 *              There are two potential problems with the use of this API:
 *
 *              o       Because the write path only set it on a successful
 *                      write, there is a race window between setting the
 *                      credential and its use to evict the pages to the
 *                      remote file server
 *
 *              o       Because a page-in may occur prior to a write, the
 *                      credential may not be set at this time, if the page-in
 *                      is not the result of a mapping established via mmap()
 *                      or map_fd().
 *
 *              In both these cases, this will be triggered from the paging
 *              path, which will instead use the credential of the current
 *              process, which in this case is either the dynamic_pager or
 *              the kernel task, both of which utilize "root" credentials.
 *
 *              This may potentially permit operations to occur which should
 *              be denied, or it may cause to be denied operations which
 *              should be permitted, depending on the configuration of the NFS
 *              server.
 */
int
ubc_setthreadcred(struct vnode *vp, proc_t p, thread_t thread)
{
        struct ubc_info *uip;
        kauth_cred_t credp;
        struct uthread  *uthread = get_bsdthread_info(thread);

        if (!UBCINFOEXISTS(vp))
                return (1); 

        vnode_lock(vp);

        uip = vp->v_ubcinfo;
        credp = uip->ui_ucred;

        if (!IS_VALID_CRED(credp)) {
                /* use per-thread cred, if assumed identity, else proc cred */
                if (uthread == NULL || (uthread->uu_flag & UT_SETUID) == 0) {
                        uip->ui_ucred = kauth_cred_proc_ref(p);
                } else {
                        uip->ui_ucred = uthread->uu_ucred;
                        kauth_cred_ref(uip->ui_ucred);
                }
        } 
        vnode_unlock(vp);

        return (0);
}


/*
 * ubc_setcred
 *
 * If they are not already set, set the credentials of the ubc_info structure
 * associated with the vnode to those of the process; otherwise leave them
 * alone.
 *
 * Parameters:  vp                      The vnode whose ubc_info creds are to
 *                                      be set
 *              p                       The process whose credentials are to
 *                                      be used
 *
 * Returns:     0                       This vnode has no associated ubc_info
 *              1                       Success
 *
 * Notes:       The return values for this function are inverted from nearly
 *              all other uses in the kernel.
 *
 *              See also ubc_setthreadcred(), above.
 *
 *              This function is considered deprecated, and generally should
 *              not be used, as it is incompatible with per-thread credentials;
 *              it exists for legacy KPI reasons.
 *
 * DEPRECATION: ubc_setcred() is being deprecated. Please use 
 *              ubc_setthreadcred() instead.
 */
int
ubc_setcred(struct vnode *vp, proc_t p)
{
        struct ubc_info *uip;
        kauth_cred_t credp;

        /* If there is no ubc_info, deny the operation */
        if ( !UBCINFOEXISTS(vp))
                return (0); 

        /*
         * Check to see if there is already a credential reference in the
         * ubc_info; if there is not, take one on the supplied credential.
         */
        vnode_lock(vp);
        uip = vp->v_ubcinfo;
        credp = uip->ui_ucred;
        if (!IS_VALID_CRED(credp)) {
                uip->ui_ucred = kauth_cred_proc_ref(p);
        } 
        vnode_unlock(vp);

        return (1);
}

/*
 * ubc_getpager
 *
 * Get the pager associated with the ubc_info associated with the vnode.
 *
 * Parameters:  vp                      The vnode to obtain the pager from
 *
 * Returns:     !VNODE_PAGER_NULL       The memory_object_t for the pager
 *              VNODE_PAGER_NULL        There is no ubc_info for this vnode
 *
 * Notes:       For each vnode that has a ubc_info associated with it, that
 *              ubc_info SHALL have a pager associated with it, so in the
 *              normal case, it's impossible to return VNODE_PAGER_NULL for
 *              a vnode with an associated ubc_info.
 */
__private_extern__ memory_object_t
ubc_getpager(struct vnode *vp)
{
        if (UBCINFOEXISTS(vp))
                return (vp->v_ubcinfo->ui_pager);

        return (0);
}


/*
 * ubc_getobject
 *
 * Get the memory object control associated with the ubc_info associated with
 * the vnode
 *
 * Parameters:  vp                      The vnode to obtain the memory object
 *                                      from
 *              flags                   DEPRECATED
 *
 * Returns:     !MEMORY_OBJECT_CONTROL_NULL
 *              MEMORY_OBJECT_CONTROL_NULL
 *
 * Notes:       Historically, if the flags were not "do not reactivate", this
 *              function would look up the memory object using the pager if
 *              it did not exist (this could be the case if the vnode had
 *              been previously reactivated).  The flags would also permit a
 *              hold to be requested, which would have created an object
 *              reference, if one had not already existed.  This usage is
 *              deprecated, as it would permit a race between finding and
 *              taking the reference vs. a single reference being dropped in
 *              another thread.
 */
memory_object_control_t
ubc_getobject(struct vnode *vp, __unused int flags)
{
        if (UBCINFOEXISTS(vp))
                return((vp->v_ubcinfo->ui_control));

        return (MEMORY_OBJECT_CONTROL_NULL);
}

boolean_t
ubc_strict_uncached_IO(struct vnode *vp)
{
        boolean_t result = FALSE;

        if (UBCINFOEXISTS(vp)) {
                result = memory_object_is_slid(vp->v_ubcinfo->ui_control);
        }
        return result;
}

/*
 * ubc_blktooff
 *
 * Convert a given block number to a memory backing object (file) offset for a
 * given vnode
 *
 * Parameters:  vp                      The vnode in which the block is located
 *              blkno                   The block number to convert
 *
 * Returns:     !-1                     The offset into the backing object
 *              -1                      There is no ubc_info associated with
 *                                      the vnode
 *              -1                      An error occurred in the underlying VFS
 *                                      while translating the block to an
 *                                      offset; the most likely cause is that
 *                                      the caller specified a block past the
 *                                      end of the file, but this could also be
 *                                      any other error from VNOP_BLKTOOFF().
 *
 * Note:        Representing the error in band loses some information, but does
 *              not occlude a valid offset, since an off_t of -1 is normally
 *              used to represent EOF.  If we had a more reliable constant in
 *              our header files for it (i.e. explicitly cast to an off_t), we
 *              would use it here instead.
 */
off_t
ubc_blktooff(vnode_t vp, daddr64_t blkno)
{
        off_t file_offset = -1;
        int error;

        if (UBCINFOEXISTS(vp)) {
                error = VNOP_BLKTOOFF(vp, blkno, &file_offset);
                if (error)
                        file_offset = -1;
        }

        return (file_offset);
}


/*
 * ubc_offtoblk
 *
 * Convert a given offset in a memory backing object into a block number for a
 * given vnode
 *
 * Parameters:  vp                      The vnode in which the offset is
 *                                      located
 *              offset                  The offset into the backing object
 *
 * Returns:     !-1                     The returned block number
 *              -1                      There is no ubc_info associated with
 *                                      the vnode
 *              -1                      An error occurred in the underlying VFS
 *                                      while translating the block to an
 *                                      offset; the most likely cause is that
 *                                      the caller specified a block past the
 *                                      end of the file, but this could also be
 *                                      any other error from VNOP_OFFTOBLK().
 *
 * Note:        Representing the error in band loses some information, but does
 *              not occlude a valid block number, since block numbers exceed
 *              the valid range for offsets, due to their relative sizes.  If
 *              we had a more reliable constant than -1 in our header files
 *              for it (i.e. explicitly cast to an daddr64_t), we would use it
 *              here instead.
 */
daddr64_t
ubc_offtoblk(vnode_t vp, off_t offset)
{
        daddr64_t blkno = -1;
        int error = 0;

        if (UBCINFOEXISTS(vp)) {
                error = VNOP_OFFTOBLK(vp, offset, &blkno);
                if (error)
                        blkno = -1;
        }

        return (blkno);
}


/*
 * ubc_pages_resident
 *
 * Determine whether or not a given vnode has pages resident via the memory
 * object control associated with the ubc_info associated with the vnode
 *
 * Parameters:  vp                      The vnode we want to know about
 *
 * Returns:     1                       Yes
 *              0                       No
 */
int
ubc_pages_resident(vnode_t vp)
{
        kern_return_t           kret;
        boolean_t                       has_pages_resident;
        
        if (!UBCINFOEXISTS(vp))
                return (0);
                        
        /*
         * The following call may fail if an invalid ui_control is specified,
         * or if there is no VM object associated with the control object.  In
         * either case, reacting to it as if there were no pages resident will
         * result in correct behavior.
         */
        kret = memory_object_pages_resident(vp->v_ubcinfo->ui_control, &has_pages_resident);
        
        if (kret != KERN_SUCCESS)
                return (0);
                
        if (has_pages_resident == TRUE)
                return (1);
                
        return (0);
}


/*
 * ubc_sync_range
 *
 * Clean and/or invalidate a range in the memory object that backs this vnode
 *
 * Parameters:  vp                      The vnode whose associated ubc_info's
 *                                      associated memory object is to have a
 *                                      range invalidated within it
 *              beg_off                 The start of the range, as an offset
 *              end_off                 The end of the range, as an offset
 *              flags                   See ubc_msync_internal()
 *
 * Returns:     1                       Success
 *              0                       Failure
 *
 * Notes:       see ubc_msync_internal() for more detailed information.
 *
 * DEPRECATED:  This interface is obsolete due to a failure to return error
 *              information needed in order to correct failures.  The currently
 *              recommended interface is ubc_msync().
 */
int
ubc_sync_range(vnode_t vp, off_t beg_off, off_t end_off, int flags)
{
        return (ubc_msync_internal(vp, beg_off, end_off, NULL, flags, NULL));
}


/*
 * ubc_msync
 *
 * Clean and/or invalidate a range in the memory object that backs this vnode
 *
 * Parameters:  vp                      The vnode whose associated ubc_info's
 *                                      associated memory object is to have a
 *                                      range invalidated within it
 *              beg_off                 The start of the range, as an offset
 *              end_off                 The end of the range, as an offset
 *              resid_off               The address of an off_t supplied by the
 *                                      caller; may be set to NULL to ignore
 *              flags                   See ubc_msync_internal()
 *
 * Returns:     0                       Success
 *              !0                      Failure; an errno is returned
 *
 * Implicit Returns:
 *              *resid_off, modified    If non-NULL, the  contents are ALWAYS
 *                                      modified; they are initialized to the
 *                                      beg_off, and in case of an I/O error,
 *                                      the difference between beg_off and the
 *                                      current value will reflect what was
 *                                      able to be written before the error
 *                                      occurred.  If no error is returned, the
 *                                      value of the resid_off is undefined; do
 *                                      NOT use it in place of end_off if you
 *                                      intend to increment from the end of the
 *                                      last call and call iteratively.
 *
 * Notes:       see ubc_msync_internal() for more detailed information.
 *
 */
errno_t
ubc_msync(vnode_t vp, off_t beg_off, off_t end_off, off_t *resid_off, int flags)
{
        int retval;
        int io_errno = 0;
        
        if (resid_off)
                *resid_off = beg_off;

        retval = ubc_msync_internal(vp, beg_off, end_off, resid_off, flags, &io_errno);

        if (retval == 0 && io_errno == 0)
                return (EINVAL);
        return (io_errno);
}


/*
 * Clean and/or invalidate a range in the memory object that backs this vnode
 *
 * Parameters:  vp                      The vnode whose associated ubc_info's
 *                                      associated memory object is to have a
 *                                      range invalidated within it
 *              beg_off                 The start of the range, as an offset
 *              end_off                 The end of the range, as an offset
 *              resid_off               The address of an off_t supplied by the
 *                                      caller; may be set to NULL to ignore
 *              flags                   MUST contain at least one of the flags
 *                                      UBC_INVALIDATE, UBC_PUSHDIRTY, or
 *                                      UBC_PUSHALL; if UBC_PUSHDIRTY is used,
 *                                      UBC_SYNC may also be specified to cause
 *                                      this function to block until the
 *                                      operation is complete.  The behavior
 *                                      of UBC_SYNC is otherwise undefined.
 *              io_errno                The address of an int to contain the
 *                                      errno from a failed I/O operation, if
 *                                      one occurs; may be set to NULL to
 *                                      ignore
 *
 * Returns:     1                       Success
 *              0                       Failure
 *
 * Implicit Returns:
 *              *resid_off, modified    The contents of this offset MAY be
 *                                      modified; in case of an I/O error, the
 *                                      difference between beg_off and the
 *                                      current value will reflect what was
 *                                      able to be written before the error
 *                                      occurred.
 *              *io_errno, modified     The contents of this offset are set to
 *                                      an errno, if an error occurs; if the
 *                                      caller supplies an io_errno parameter,
 *                                      they should be careful to initialize it
 *                                      to 0 before calling this function to
 *                                      enable them to distinguish an error
 *                                      with a valid *resid_off from an invalid
 *                                      one, and to avoid potentially falsely
 *                                      reporting an error, depending on use.
 *
 * Notes:       If there is no ubc_info associated with the vnode supplied,
 *              this function immediately returns success.
 *
 *              If the value of end_off is less than or equal to beg_off, this
 *              function immediately returns success; that is, end_off is NOT
 *              inclusive.
 *
 *              IMPORTANT: one of the flags UBC_INVALIDATE, UBC_PUSHDIRTY, or
 *              UBC_PUSHALL MUST be specified; that is, it is NOT possible to
 *              attempt to block on in-progress I/O by calling this function
 *              with UBC_PUSHDIRTY, and then later call it with just UBC_SYNC
 *              in order to block pending on the I/O already in progress.
 *
 *              The start offset is truncated to the page boundary and the
 *              size is adjusted to include the last page in the range; that
 *              is, end_off on exactly a page boundary will not change if it
 *              is rounded, and the range of bytes written will be from the
 *              truncate beg_off to the rounded (end_off - 1).
 */
static int
ubc_msync_internal(vnode_t vp, off_t beg_off, off_t end_off, off_t *resid_off, int flags, int *io_errno)
{
        memory_object_size_t    tsize;
        kern_return_t           kret;
        int request_flags = 0;
        int flush_flags   = MEMORY_OBJECT_RETURN_NONE;
        
        if ( !UBCINFOEXISTS(vp))
                return (0);
        if ((flags & (UBC_INVALIDATE | UBC_PUSHDIRTY | UBC_PUSHALL)) == 0)
                return (0);
        if (end_off <= beg_off)
                return (1);

        if (flags & UBC_INVALIDATE)
                /*
                 * discard the resident pages
                 */
                request_flags = (MEMORY_OBJECT_DATA_FLUSH | MEMORY_OBJECT_DATA_NO_CHANGE);

        if (flags & UBC_SYNC)
                /*
                 * wait for all the I/O to complete before returning
                 */
                request_flags |= MEMORY_OBJECT_IO_SYNC;

        if (flags & UBC_PUSHDIRTY)
                /*
                 * we only return the dirty pages in the range
                 */
                flush_flags = MEMORY_OBJECT_RETURN_DIRTY;

        if (flags & UBC_PUSHALL)
                /*
                 * then return all the interesting pages in the range (both
                 * dirty and precious) to the pager
                 */
                flush_flags = MEMORY_OBJECT_RETURN_ALL;

        beg_off = trunc_page_64(beg_off);
        end_off = round_page_64(end_off);
        tsize   = (memory_object_size_t)end_off - beg_off;

        /* flush and/or invalidate pages in the range requested */
        kret = memory_object_lock_request(vp->v_ubcinfo->ui_control,
                                          beg_off, tsize,
                                          (memory_object_offset_t *)resid_off,
                                          io_errno, flush_flags, request_flags,
                                          VM_PROT_NO_CHANGE);
        
        return ((kret == KERN_SUCCESS) ? 1 : 0);
}


/*
 * ubc_msync_internal
 *
 * Explicitly map a vnode that has an associate ubc_info, and add a reference
 * to it for the ubc system, if there isn't one already, so it will not be
 * recycled while it's in use, and set flags on the ubc_info to indicate that
 * we have done this
 *
 * Parameters:  vp                      The vnode to map
 *              flags                   The mapping flags for the vnode; this
 *                                      will be a combination of one or more of
 *                                      PROT_READ, PROT_WRITE, and PROT_EXEC
 *
 * Returns:     0                       Success
 *              EPERM                   Permission was denied
 *
 * Notes:       An I/O reference on the vnode must already be held on entry
 *
 *              If there is no ubc_info associated with the vnode, this function
 *              will return success.
 *
 *              If a permission error occurs, this function will return
 *              failure; all other failures will cause this function to return
 *              success.
 *
 *              IMPORTANT: This is an internal use function, and its symbols
 *              are not exported, hence its error checking is not very robust.
 *              It is primarily used by:
 *
 *              o       mmap(), when mapping a file
 *              o       The deprecated map_fd() interface, when mapping a file
 *              o       When mapping a shared file (a shared library in the
 *                      shared segment region)
 *              o       When loading a program image during the exec process
 *
 *              ...all of these uses ignore the return code, and any fault that
 *              results later because of a failure is handled in the fix-up path
 *              of the fault handler.  The interface exists primarily as a
 *              performance hint.
 *
 *              Given that third party implementation of the type of interfaces
 *              that would use this function, such as alternative executable
 *              formats, etc., are unsupported, this function is not exported
 *              for general use.
 *
 *              The extra reference is held until the VM system unmaps the
 *              vnode from its own context to maintain a vnode reference in
 *              cases like open()/mmap()/close(), which leave the backing
 *              object referenced by a mapped memory region in a process
 *              address space.
 */
__private_extern__ int
ubc_map(vnode_t vp, int flags)
{
        struct ubc_info *uip;
        int error = 0;
        int need_ref = 0;
        int need_wakeup = 0;

        if (UBCINFOEXISTS(vp)) {

                vnode_lock(vp);
                uip = vp->v_ubcinfo;

                while (ISSET(uip->ui_flags, UI_MAPBUSY)) {
                        SET(uip->ui_flags, UI_MAPWAITING);
                        (void) msleep(&uip->ui_flags, &vp->v_lock,
                                      PRIBIO, "ubc_map", NULL);
                }
                SET(uip->ui_flags, UI_MAPBUSY);
                vnode_unlock(vp);

                error = VNOP_MMAP(vp, flags, vfs_context_current());

                if (error != EPERM)
                        error = 0;

                vnode_lock_spin(vp);

                if (error == 0) {
                        if ( !ISSET(uip->ui_flags, UI_ISMAPPED))
                                need_ref = 1;
                        SET(uip->ui_flags, (UI_WASMAPPED | UI_ISMAPPED));
                }
                CLR(uip->ui_flags, UI_MAPBUSY);

                if (ISSET(uip->ui_flags, UI_MAPWAITING)) {
                        CLR(uip->ui_flags, UI_MAPWAITING);
                        need_wakeup = 1;
                }
                vnode_unlock(vp);

                if (need_wakeup)
                        wakeup(&uip->ui_flags);

                if (need_ref)
                        vnode_ref(vp);
        }
        return (error);
}


/*
 * ubc_destroy_named
 *
 * Destroy the named memory object associated with the ubc_info control object
 * associated with the designated vnode, if there is a ubc_info associated
 * with the vnode, and a control object is associated with it
 *
 * Parameters:  vp                      The designated vnode
 *
 * Returns:     (void)
 *
 * Notes:       This function is called on vnode termination for all vnodes,
 *              and must therefore not assume that there is a ubc_info that is
 *              associated with the vnode, nor that there is a control object
 *              associated with the ubc_info.
 *
 *              If all the conditions necessary are present, this function
 *              calls memory_object_destory(), which will in turn end up
 *              calling ubc_unmap() to release any vnode references that were
 *              established via ubc_map().
 *
 *              IMPORTANT: This is an internal use function that is used
 *              exclusively by the internal use function vclean().
 */
__private_extern__ void
ubc_destroy_named(vnode_t vp)
{
        memory_object_control_t control;
        struct ubc_info *uip;
        kern_return_t kret;

        if (UBCINFOEXISTS(vp)) {
                uip = vp->v_ubcinfo;

                /* Terminate the memory object  */
                control = ubc_getobject(vp, UBC_HOLDOBJECT);
                if (control != MEMORY_OBJECT_CONTROL_NULL) {
                        kret = memory_object_destroy(control, 0);
                        if (kret != KERN_SUCCESS)
                                panic("ubc_destroy_named: memory_object_destroy failed");
                }
        }
}


/*
 * ubc_isinuse
 *
 * Determine whether or not a vnode is currently in use by ubc at a level in
 * excess of the requested busycount
 *
 * Parameters:  vp                      The vnode to check
 *              busycount               The threshold busy count, used to bias
 *                                      the count usually already held by the
 *                                      caller to avoid races
 *
 * Returns:     1                       The vnode is in use over the threshold
 *              0                       The vnode is not in use over the
 *                                      threshold
 *
 * Notes:       Because the vnode is only held locked while actually asking
 *              the use count, this function only represents a snapshot of the
 *              current state of the vnode.  If more accurate information is
 *              required, an additional busycount should be held by the caller
 *              and a non-zero busycount used.
 *
 *              If there is no ubc_info associated with the vnode, this
 *              function will report that the vnode is not in use by ubc.
 */
int
ubc_isinuse(struct vnode *vp, int busycount)
{
        if ( !UBCINFOEXISTS(vp))
                return (0);
        return(ubc_isinuse_locked(vp, busycount, 0));
}


/*
 * ubc_isinuse_locked
 *
 * Determine whether or not a vnode is currently in use by ubc at a level in
 * excess of the requested busycount
 *
 * Parameters:  vp                      The vnode to check
 *              busycount               The threshold busy count, used to bias
 *                                      the count usually already held by the
 *                                      caller to avoid races
 *              locked                  True if the vnode is already locked by
 *                                      the caller
 *
 * Returns:     1                       The vnode is in use over the threshold
 *              0                       The vnode is not in use over the
 *                                      threshold
 *
 * Notes:       If the vnode is not locked on entry, it is locked while
 *              actually asking the use count.  If this is the case, this
 *              function only represents a snapshot of the current state of
 *              the vnode.  If more accurate information is required, the
 *              vnode lock should be held by the caller, otherwise an
 *              additional busycount should be held by the caller and a
 *              non-zero busycount used.
 *
 *              If there is no ubc_info associated with the vnode, this
 *              function will report that the vnode is not in use by ubc.
 */
int
ubc_isinuse_locked(struct vnode *vp, int busycount, int locked)
{
        int retval = 0;


        if (!locked)
                vnode_lock_spin(vp);

        if ((vp->v_usecount - vp->v_kusecount) > busycount)
                retval = 1;

        if (!locked)
                vnode_unlock(vp);
        return (retval);
}


/*
 * ubc_unmap
 *
 * Reverse the effects of a ubc_map() call for a given vnode
 *
 * Parameters:  vp                      vnode to unmap from ubc
 *
 * Returns:     (void)
 *
 * Notes:       This is an internal use function used by vnode_pager_unmap().
 *              It will attempt to obtain a reference on the supplied vnode,
 *              and if it can do so, and there is an associated ubc_info, and
 *              the flags indicate that it was mapped via ubc_map(), then the
 *              flag is cleared, the mapping removed, and the reference taken
 *              by ubc_map() is released.
 *
 *              IMPORTANT: This MUST only be called by the VM
 *              to prevent race conditions.
 */
__private_extern__ void
ubc_unmap(struct vnode *vp)
{
        struct ubc_info *uip;
        int     need_rele = 0;
        int     need_wakeup = 0;

        if (vnode_getwithref(vp))
                return;

        if (UBCINFOEXISTS(vp)) {
                vnode_lock(vp);
                uip = vp->v_ubcinfo;

                while (ISSET(uip->ui_flags, UI_MAPBUSY)) {
                        SET(uip->ui_flags, UI_MAPWAITING);
                        (void) msleep(&uip->ui_flags, &vp->v_lock,
                                      PRIBIO, "ubc_unmap", NULL);
                }
                SET(uip->ui_flags, UI_MAPBUSY);

                if (ISSET(uip->ui_flags, UI_ISMAPPED)) {
                        CLR(uip->ui_flags, UI_ISMAPPED);
                        need_rele = 1;
                }
                vnode_unlock(vp);
                
                if (need_rele) {
                        (void)VNOP_MNOMAP(vp, vfs_context_current());
                        vnode_rele(vp);
                }

                vnode_lock_spin(vp);

                CLR(uip->ui_flags, UI_MAPBUSY);
                if (ISSET(uip->ui_flags, UI_MAPWAITING)) {
                        CLR(uip->ui_flags, UI_MAPWAITING);
                        need_wakeup = 1;
                }
                vnode_unlock(vp);

                if (need_wakeup)
                        wakeup(&uip->ui_flags);

        }
        /*
         * the drop of the vnode ref will cleanup
         */
        vnode_put(vp);
}


/*
 * ubc_page_op
 *
 * Manipulate individual page state for a vnode with an associated ubc_info
 * with an associated memory object control.
 *
 * Parameters:  vp                      The vnode backing the page
 *              f_offset                A file offset interior to the page
 *              ops                     The operations to perform, as a bitmap
 *                                      (see below for more information)
 *              phys_entryp             The address of a ppnum_t; may be NULL
 *                                      to ignore
 *              flagsp                  A pointer to an int to contain flags;
 *                                      may be NULL to ignore
 *
 * Returns:     KERN_SUCCESS            Success
 *              KERN_INVALID_ARGUMENT   If the memory object control has no VM
 *                                      object associated
 *              KERN_INVALID_OBJECT     If UPL_POP_PHYSICAL and the object is
 *                                      not physically contiguous
 *              KERN_INVALID_OBJECT     If !UPL_POP_PHYSICAL and the object is
 *                                      physically contiguous
 *              KERN_FAILURE            If the page cannot be looked up
 *
 * Implicit Returns:
 *              *phys_entryp (modified) If phys_entryp is non-NULL and
 *                                      UPL_POP_PHYSICAL
 *              *flagsp (modified)      If flagsp is non-NULL and there was
 *                                      !UPL_POP_PHYSICAL and a KERN_SUCCESS
 *
 * Notes:       For object boundaries, it is considerably more efficient to
 *              ensure that f_offset is in fact on a page boundary, as this
 *              will avoid internal use of the hash table to identify the
 *              page, and would therefore skip a number of early optimizations.
 *              Since this is a page operation anyway, the caller should try
 *              to pass only a page aligned offset because of this.
 *
 *              *flagsp may be modified even if this function fails.  If it is
 *              modified, it will contain the condition of the page before the
 *              requested operation was attempted; these will only include the
 *              bitmap flags, and not the PL_POP_PHYSICAL, UPL_POP_DUMP,
 *              UPL_POP_SET, or UPL_POP_CLR bits.
 *
 *              The flags field may contain a specific operation, such as
 *              UPL_POP_PHYSICAL or UPL_POP_DUMP:
 *
 *              o       UPL_POP_PHYSICAL        Fail if not contiguous; if
 *                                              *phys_entryp and successful, set
 *                                              *phys_entryp
 *              o       UPL_POP_DUMP            Dump the specified page
 *
 *              Otherwise, it is treated as a bitmap of one or more page
 *              operations to perform on the final memory object; allowable
 *              bit values are:
 *
 *              o       UPL_POP_DIRTY           The page is dirty
 *              o       UPL_POP_PAGEOUT         The page is paged out
 *              o       UPL_POP_PRECIOUS        The page is precious
 *              o       UPL_POP_ABSENT          The page is absent
 *              o       UPL_POP_BUSY            The page is busy
 *
 *              If the page status is only being queried and not modified, then
 *              not other bits should be specified.  However, if it is being
 *              modified, exactly ONE of the following bits should be set:
 *
 *              o       UPL_POP_SET             Set the current bitmap bits
 *              o       UPL_POP_CLR             Clear the current bitmap bits
 *
 *              Thus to effect a combination of setting an clearing, it may be
 *              necessary to call this function twice.  If this is done, the
 *              set should be used before the clear, since clearing may trigger
 *              a wakeup on the destination page, and if the page is backed by
 *              an encrypted swap file, setting will trigger the decryption
 *              needed before the wakeup occurs.
 */
kern_return_t
ubc_page_op(
        struct vnode    *vp,
        off_t           f_offset,
        int             ops,
        ppnum_t *phys_entryp,
        int             *flagsp)
{
        memory_object_control_t         control;

        control = ubc_getobject(vp, UBC_FLAGS_NONE);
        if (control == MEMORY_OBJECT_CONTROL_NULL)
                return KERN_INVALID_ARGUMENT;

        return (memory_object_page_op(control,
                                      (memory_object_offset_t)f_offset,
                                      ops,
                                      phys_entryp,
                                      flagsp));
}


/*
 * ubc_range_op
 *
 * Manipulate page state for a range of memory for a vnode with an associated
 * ubc_info with an associated memory object control, when page level state is
 * not required to be returned from the call (i.e. there are no phys_entryp or
 * flagsp parameters to this call, and it takes a range which may contain
 * multiple pages, rather than an offset interior to a single page).
 *
 * Parameters:  vp                      The vnode backing the page
 *              f_offset_beg            A file offset interior to the start page
 *              f_offset_end            A file offset interior to the end page
 *              ops                     The operations to perform, as a bitmap
 *                                      (see below for more information)
 *              range                   The address of an int; may be NULL to
 *                                      ignore
 *
 * Returns:     KERN_SUCCESS            Success
 *              KERN_INVALID_ARGUMENT   If the memory object control has no VM
 *                                      object associated
 *              KERN_INVALID_OBJECT     If the object is physically contiguous
 *
 * Implicit Returns:
 *              *range (modified)       If range is non-NULL, its contents will
 *                                      be modified to contain the number of
 *                                      bytes successfully operated upon.
 *
 * Notes:       IMPORTANT: This function cannot be used on a range that
 *              consists of physically contiguous pages.
 *
 *              For object boundaries, it is considerably more efficient to
 *              ensure that f_offset_beg and f_offset_end are in fact on page
 *              boundaries, as this will avoid internal use of the hash table
 *              to identify the page, and would therefore skip a number of
 *              early optimizations.  Since this is an operation on a set of
 *              pages anyway, the caller should try to pass only a page aligned
 *              offsets because of this.
 *
 *              *range will be modified only if this function succeeds.
 *
 *              The flags field MUST contain a specific operation; allowable
 *              values are:
 *
 *              o       UPL_ROP_ABSENT  Returns the extent of the range
 *                                      presented which is absent, starting
 *                                      with the start address presented
 *
 *              o       UPL_ROP_PRESENT Returns the extent of the range
 *                                      presented which is present (resident),
 *                                      starting with the start address
 *                                      presented
 *              o       UPL_ROP_DUMP    Dump the pages which are found in the
 *                                      target object for the target range.
 *
 *              IMPORTANT: For UPL_ROP_ABSENT and UPL_ROP_PRESENT; if there are
 *              multiple regions in the range, only the first matching region
 *              is returned.
 */
kern_return_t
ubc_range_op(
        struct vnode    *vp,
        off_t           f_offset_beg,
        off_t           f_offset_end,
        int             ops,
        int             *range)
{
        memory_object_control_t         control;

        control = ubc_getobject(vp, UBC_FLAGS_NONE);
        if (control == MEMORY_OBJECT_CONTROL_NULL)
                return KERN_INVALID_ARGUMENT;

        return (memory_object_range_op(control,
                                      (memory_object_offset_t)f_offset_beg,
                                      (memory_object_offset_t)f_offset_end,
                                      ops,
                                      range));
}


/*
 * ubc_create_upl
 *
 * Given a vnode, cause the population of a portion of the vm_object; based on
 * the nature of the request, the pages returned may contain valid data, or
 * they may be uninitialized.
 *
 * Parameters:  vp                      The vnode from which to create the upl
 *              f_offset                The start offset into the backing store
 *                                      represented by the vnode
 *              bufsize                 The size of the upl to create
 *              uplp                    Pointer to the upl_t to receive the
 *                                      created upl; MUST NOT be NULL
 *              plp                     Pointer to receive the internal page
 *                                      list for the created upl; MAY be NULL
 *                                      to ignore
 *
 * Returns:     KERN_SUCCESS            The requested upl has been created
 *              KERN_INVALID_ARGUMENT   The bufsize argument is not an even
 *                                      multiple of the page size
 *              KERN_INVALID_ARGUMENT   There is no ubc_info associated with
 *                                      the vnode, or there is no memory object
 *                                      control associated with the ubc_info 
 *      memory_object_upl_request:KERN_INVALID_VALUE
 *                                      The supplied upl_flags argument is
 *                                      invalid
 * Implicit Returns:
 *              *uplp (modified)        
 *              *plp (modified)         If non-NULL, the value of *plp will be
 *                                      modified to point to the internal page
 *                                      list; this modification may occur even
 *                                      if this function is unsuccessful, in
 *                                      which case the contents may be invalid
 *
 * Note:        If successful, the returned *uplp MUST subsequently be freed
 *              via a call to ubc_upl_commit(), ubc_upl_commit_range(),
 *              ubc_upl_abort(), or ubc_upl_abort_range().
 */
kern_return_t
ubc_create_upl(
        struct vnode    *vp,
        off_t           f_offset,
        int             bufsize,
        upl_t           *uplp,
        upl_page_info_t **plp,
        int             uplflags)
{
        memory_object_control_t         control;
        kern_return_t                   kr;

        if (plp != NULL)
                *plp = NULL;
        *uplp = NULL;
        
        if (bufsize & 0xfff)
                return KERN_INVALID_ARGUMENT;

        if (bufsize > MAX_UPL_SIZE * PAGE_SIZE)
                return KERN_INVALID_ARGUMENT;

        if (uplflags & (UPL_UBC_MSYNC | UPL_UBC_PAGEOUT | UPL_UBC_PAGEIN)) {

                if (uplflags & UPL_UBC_MSYNC) {
                        uplflags &= UPL_RET_ONLY_DIRTY;

                        uplflags |= UPL_COPYOUT_FROM | UPL_CLEAN_IN_PLACE |
                                    UPL_SET_INTERNAL | UPL_SET_LITE;

                } else if (uplflags & UPL_UBC_PAGEOUT) {
                        uplflags &= UPL_RET_ONLY_DIRTY;

                        if (uplflags & UPL_RET_ONLY_DIRTY)
                                uplflags |= UPL_NOBLOCK;

                        uplflags |= UPL_FOR_PAGEOUT | UPL_CLEAN_IN_PLACE |
                                    UPL_COPYOUT_FROM | UPL_SET_INTERNAL | UPL_SET_LITE;
                } else {
                        uplflags |= UPL_RET_ONLY_ABSENT |
                                    UPL_NO_SYNC | UPL_CLEAN_IN_PLACE |
                                    UPL_SET_INTERNAL | UPL_SET_LITE;

                        /*
                         * if the requested size == PAGE_SIZE, we don't want to set
                         * the UPL_NOBLOCK since we may be trying to recover from a
                         * previous partial pagein I/O that occurred because we were low
                         * on memory and bailed early in order to honor the UPL_NOBLOCK...
                         * since we're only asking for a single page, we can block w/o fear
                         * of tying up pages while waiting for more to become available
                         */
                        if (bufsize > PAGE_SIZE)
                                uplflags |= UPL_NOBLOCK;
                }
        } else {
                uplflags &= ~UPL_FOR_PAGEOUT;

                if (uplflags & UPL_WILL_BE_DUMPED) {
                        uplflags &= ~UPL_WILL_BE_DUMPED;
                        uplflags |= (UPL_NO_SYNC|UPL_SET_INTERNAL);
                } else
                        uplflags |= (UPL_NO_SYNC|UPL_CLEAN_IN_PLACE|UPL_SET_INTERNAL);
        }
        control = ubc_getobject(vp, UBC_FLAGS_NONE);
        if (control == MEMORY_OBJECT_CONTROL_NULL)
                return KERN_INVALID_ARGUMENT;

        kr = memory_object_upl_request(control, f_offset, bufsize, uplp, NULL, NULL, uplflags);
        if (kr == KERN_SUCCESS && plp != NULL)
                *plp = UPL_GET_INTERNAL_PAGE_LIST(*uplp);
        return kr;
}
                
                                                              
/*
 * ubc_upl_maxbufsize
 *
 * Return the maximum bufsize ubc_create_upl( ) will take.
 *
 * Parameters:  none
 *
 * Returns:     maximum size buffer (in bytes) ubc_create_upl( ) will take.
 */
upl_size_t 
ubc_upl_maxbufsize(
        void)
{
        return(MAX_UPL_SIZE * PAGE_SIZE);
}

/*
 * ubc_upl_map
 *
 * Map the page list assocated with the supplied upl into the kernel virtual
 * address space at the virtual address indicated by the dst_addr argument;
 * the entire upl is mapped
 *
 * Parameters:  upl                     The upl to map
 *              dst_addr                The address at which to map the upl
 *
 * Returns:     KERN_SUCCESS            The upl has been mapped
 *              KERN_INVALID_ARGUMENT   The upl is UPL_NULL
 *              KERN_FAILURE            The upl is already mapped
 *      vm_map_enter:KERN_INVALID_ARGUMENT
 *                                      A failure code from vm_map_enter() due
 *                                      to an invalid argument
 */
kern_return_t
ubc_upl_map(
        upl_t           upl,
        vm_offset_t     *dst_addr)
{
        return (vm_upl_map(kernel_map, upl, dst_addr));
}


/*
 * ubc_upl_unmap
 *
 * Unmap the page list assocated with the supplied upl from the kernel virtual
 * address space; the entire upl is unmapped.
 *
 * Parameters:  upl                     The upl to unmap
 *
 * Returns:     KERN_SUCCESS            The upl has been unmapped
 *              KERN_FAILURE            The upl is not currently mapped
 *              KERN_INVALID_ARGUMENT   If the upl is UPL_NULL
 */
kern_return_t
ubc_upl_unmap(
        upl_t   upl)
{
        return(vm_upl_unmap(kernel_map, upl));
}


/*
 * ubc_upl_commit
 *
 * Commit the contents of the upl to the backing store
 *
 * Parameters:  upl                     The upl to commit
 *
 * Returns:     KERN_SUCCESS            The upl has been committed
 *              KERN_INVALID_ARGUMENT   The supplied upl was UPL_NULL
 *              KERN_FAILURE            The supplied upl does not represent
 *                                      device memory, and the offset plus the
 *                                      size would exceed the actual size of
 *                                      the upl
 *
 * Notes:       In practice, the only return value for this function should be
 *              KERN_SUCCESS, unless there has been data structure corruption;
 *              since the upl is deallocated regardless of success or failure,
 *              there's really nothing to do about this other than panic.
 *
 *              IMPORTANT: Use of this function should not be mixed with use of
 *              ubc_upl_commit_range(), due to the unconditional deallocation
 *              by this function.
 */
kern_return_t
ubc_upl_commit(
        upl_t                   upl)
{
        upl_page_info_t *pl;
        kern_return_t   kr;

        pl = UPL_GET_INTERNAL_PAGE_LIST(upl);
        kr = upl_commit(upl, pl, MAX_UPL_SIZE);
        upl_deallocate(upl);
        return kr;
}


/*
 * ubc_upl_commit
 *
 * Commit the contents of the specified range of the upl to the backing store
 *
 * Parameters:  upl                     The upl to commit
 *              offset                  The offset into the upl
 *              size                    The size of the region to be committed,
 *                                      starting at the specified offset
 *              flags                   commit type (see below)
 *
 * Returns:     KERN_SUCCESS            The range has been committed
 *              KERN_INVALID_ARGUMENT   The supplied upl was UPL_NULL
 *              KERN_FAILURE            The supplied upl does not represent
 *                                      device memory, and the offset plus the
 *                                      size would exceed the actual size of
 *                                      the upl
 *
 * Notes:       IMPORTANT: If the commit is successful, and the object is now
 *              empty, the upl will be deallocated.  Since the caller cannot
 *              check that this is the case, the UPL_COMMIT_FREE_ON_EMPTY flag
 *              should generally only be used when the offset is 0 and the size
 *              is equal to the upl size.
 *
 *              The flags argument is a bitmap of flags on the rage of pages in
 *              the upl to be committed; allowable flags are:
 *
 *              o       UPL_COMMIT_FREE_ON_EMPTY        Free the upl when it is
 *                                                      both empty and has been
 *                                                      successfully committed
 *              o       UPL_COMMIT_CLEAR_DIRTY          Clear each pages dirty
 *                                                      bit; will prevent a
 *                                                      later pageout
 *              o       UPL_COMMIT_SET_DIRTY            Set each pages dirty
 *                                                      bit; will cause a later
 *                                                      pageout
 *              o       UPL_COMMIT_INACTIVATE           Clear each pages
 *                                                      reference bit; the page
 *                                                      will not be accessed
 *              o       UPL_COMMIT_ALLOW_ACCESS         Unbusy each page; pages
 *                                                      become busy when an
 *                                                      IOMemoryDescriptor is
 *                                                      mapped or redirected,
 *                                                      and we have to wait for
 *                                                      an IOKit driver
 *
 *              The flag UPL_COMMIT_NOTIFY_EMPTY is used internally, and should
 *              not be specified by the caller.
 *
 *              The UPL_COMMIT_CLEAR_DIRTY and UPL_COMMIT_SET_DIRTY flags are
 *              mutually exclusive, and should not be combined.
 */
kern_return_t
ubc_upl_commit_range(
        upl_t                   upl,
        upl_offset_t            offset,
        upl_size_t              size,
        int                             flags)
{
        upl_page_info_t *pl;
        boolean_t               empty;
        kern_return_t   kr;

        if (flags & UPL_COMMIT_FREE_ON_EMPTY)
                flags |= UPL_COMMIT_NOTIFY_EMPTY;

        if (flags & UPL_COMMIT_KERNEL_ONLY_FLAGS) {
                return KERN_INVALID_ARGUMENT;
        }

        pl = UPL_GET_INTERNAL_PAGE_LIST(upl);

        kr = upl_commit_range(upl, offset, size, flags,
                                                  pl, MAX_UPL_SIZE, &empty);

        if((flags & UPL_COMMIT_FREE_ON_EMPTY) && empty)
                upl_deallocate(upl);

        return kr;
}


/*
 * ubc_upl_abort_range
 *
 * Abort the contents of the specified range of the specified upl
 *
 * Parameters:  upl                     The upl to abort
 *              offset                  The offset into the upl
 *              size                    The size of the region to be aborted,
 *                                      starting at the specified offset
 *              abort_flags             abort type (see below)
 *
 * Returns:     KERN_SUCCESS            The range has been aborted
 *              KERN_INVALID_ARGUMENT   The supplied upl was UPL_NULL
 *              KERN_FAILURE            The supplied upl does not represent
 *                                      device memory, and the offset plus the
 *                                      size would exceed the actual size of
 *                                      the upl
 *
 * Notes:       IMPORTANT: If the abort is successful, and the object is now
 *              empty, the upl will be deallocated.  Since the caller cannot
 *              check that this is the case, the UPL_ABORT_FREE_ON_EMPTY flag
 *              should generally only be used when the offset is 0 and the size
 *              is equal to the upl size.
 *
 *              The abort_flags argument is a bitmap of flags on the range of
 *              pages in the upl to be aborted; allowable flags are:
 *
 *              o       UPL_ABORT_FREE_ON_EMPTY Free the upl when it is both
 *                                              empty and has been successfully
 *                                              aborted
 *              o       UPL_ABORT_RESTART       The operation must be restarted
 *              o       UPL_ABORT_UNAVAILABLE   The pages are unavailable
 *              o       UPL_ABORT_ERROR         An I/O error occurred
 *              o       UPL_ABORT_DUMP_PAGES    Just free the pages
 *              o       UPL_ABORT_NOTIFY_EMPTY  RESERVED
 *              o       UPL_ABORT_ALLOW_ACCESS  RESERVED
 *
 *              The UPL_ABORT_NOTIFY_EMPTY is an internal use flag and should
 *              not be specified by the caller.  It is intended to fulfill the
 *              same role as UPL_COMMIT_NOTIFY_EMPTY does in the function
 *              ubc_upl_commit_range(), but is never referenced internally.
 *
 *              The UPL_ABORT_ALLOW_ACCESS is defined, but neither set nor
 *              referenced; do not use it.
 */
kern_return_t
ubc_upl_abort_range(
        upl_t                   upl,
        upl_offset_t            offset,
        upl_size_t              size,
        int                             abort_flags)
{
        kern_return_t   kr;
        boolean_t               empty = FALSE;

        if (abort_flags & UPL_ABORT_FREE_ON_EMPTY)
                abort_flags |= UPL_ABORT_NOTIFY_EMPTY;

        kr = upl_abort_range(upl, offset, size, abort_flags, &empty);

        if((abort_flags & UPL_ABORT_FREE_ON_EMPTY) && empty)
                upl_deallocate(upl);

        return kr;
}


/*
 * ubc_upl_abort
 *
 * Abort the contents of the specified upl
 *
 * Parameters:  upl                     The upl to abort
 *              abort_type              abort type (see below)
 *
 * Returns:     KERN_SUCCESS            The range has been aborted
 *              KERN_INVALID_ARGUMENT   The supplied upl was UPL_NULL
 *              KERN_FAILURE            The supplied upl does not represent
 *                                      device memory, and the offset plus the
 *                                      size would exceed the actual size of
 *                                      the upl
 *
 * Notes:       IMPORTANT: If the abort is successful, and the object is now
 *              empty, the upl will be deallocated.  Since the caller cannot
 *              check that this is the case, the UPL_ABORT_FREE_ON_EMPTY flag
 *              should generally only be used when the offset is 0 and the size
 *              is equal to the upl size.
 *
 *              The abort_type is a bitmap of flags on the range of
 *              pages in the upl to be aborted; allowable flags are:
 *
 *              o       UPL_ABORT_FREE_ON_EMPTY Free the upl when it is both
 *                                              empty and has been successfully
 *                                              aborted
 *              o       UPL_ABORT_RESTART       The operation must be restarted
 *              o       UPL_ABORT_UNAVAILABLE   The pages are unavailable
 *              o       UPL_ABORT_ERROR         An I/O error occurred
 *              o       UPL_ABORT_DUMP_PAGES    Just free the pages
 *              o       UPL_ABORT_NOTIFY_EMPTY  RESERVED
 *              o       UPL_ABORT_ALLOW_ACCESS  RESERVED
 *
 *              The UPL_ABORT_NOTIFY_EMPTY is an internal use flag and should
 *              not be specified by the caller.  It is intended to fulfill the
 *              same role as UPL_COMMIT_NOTIFY_EMPTY does in the function
 *              ubc_upl_commit_range(), but is never referenced internally.
 *
 *              The UPL_ABORT_ALLOW_ACCESS is defined, but neither set nor
 *              referenced; do not use it.
 */
kern_return_t
ubc_upl_abort(
        upl_t                   upl,
        int                             abort_type)
{
        kern_return_t   kr;

        kr = upl_abort(upl, abort_type);
        upl_deallocate(upl);
        return kr;
}


/*
 * ubc_upl_pageinfo
 *
 *  Retrieve the internal page list for the specified upl
 *
 * Parameters:  upl                     The upl to obtain the page list from
 *
 * Returns:     !NULL                   The (upl_page_info_t *) for the page
 *                                      list internal to the upl
 *              NULL                    Error/no page list associated
 *
 * Notes:       IMPORTANT: The function is only valid on internal objects
 *              where the list request was made with the UPL_INTERNAL flag.
 *
 *              This function is a utility helper function, since some callers
 *              may not have direct access to the header defining the macro,
 *              due to abstraction layering constraints.
 */
upl_page_info_t *
ubc_upl_pageinfo(
        upl_t                   upl)
{              
        return (UPL_GET_INTERNAL_PAGE_LIST(upl));
}


int 
UBCINFOEXISTS(struct vnode * vp)
{
        return((vp) && ((vp)->v_type == VREG) && ((vp)->v_ubcinfo != UBC_INFO_NULL));
}


void
ubc_upl_range_needed(
        upl_t           upl,
        int             index,
        int             count)
{
        upl_range_needed(upl, index, count);
}


/*
 * CODE SIGNING
 */
#define CS_BLOB_PAGEABLE 0
static volatile SInt32 cs_blob_size = 0;
static volatile SInt32 cs_blob_count = 0;
static SInt32 cs_blob_size_peak = 0;
static UInt32 cs_blob_size_max = 0;
static SInt32 cs_blob_count_peak = 0;

int cs_validation = 1;

#ifndef SECURE_KERNEL
SYSCTL_INT(_vm, OID_AUTO, cs_validation, CTLFLAG_RW | CTLFLAG_LOCKED, &cs_validation, 0, "Do validate code signatures");
#endif
SYSCTL_INT(_vm, OID_AUTO, cs_blob_count, CTLFLAG_RD | CTLFLAG_LOCKED, (int *)(uintptr_t)&cs_blob_count, 0, "Current number of code signature blobs");
SYSCTL_INT(_vm, OID_AUTO, cs_blob_size, CTLFLAG_RD | CTLFLAG_LOCKED, (int *)(uintptr_t)&cs_blob_size, 0, "Current size of all code signature blobs");
SYSCTL_INT(_vm, OID_AUTO, cs_blob_count_peak, CTLFLAG_RD | CTLFLAG_LOCKED, &cs_blob_count_peak, 0, "Peak number of code signature blobs");
SYSCTL_INT(_vm, OID_AUTO, cs_blob_size_peak, CTLFLAG_RD | CTLFLAG_LOCKED, &cs_blob_size_peak, 0, "Peak size of code signature blobs");
SYSCTL_INT(_vm, OID_AUTO, cs_blob_size_max, CTLFLAG_RD | CTLFLAG_LOCKED, &cs_blob_size_max, 0, "Size of biggest code signature blob");

kern_return_t
ubc_cs_blob_allocate(
        vm_offset_t     *blob_addr_p,
        vm_size_t       *blob_size_p)
{
        kern_return_t   kr;

#if CS_BLOB_PAGEABLE
        *blob_size_p = round_page(*blob_size_p);
        kr = kmem_alloc(kernel_map, blob_addr_p, *blob_size_p);
#else   /* CS_BLOB_PAGEABLE */
        *blob_addr_p = (vm_offset_t) kalloc(*blob_size_p);
        if (*blob_addr_p == 0) {
                kr = KERN_NO_SPACE;
        } else {
                kr = KERN_SUCCESS;
        }
#endif  /* CS_BLOB_PAGEABLE */
        return kr;
}

void
ubc_cs_blob_deallocate(
        vm_offset_t     blob_addr,
        vm_size_t       blob_size)
{
#if CS_BLOB_PAGEABLE
        kmem_free(kernel_map, blob_addr, blob_size);
#else   /* CS_BLOB_PAGEABLE */
        kfree((void *) blob_addr, blob_size);
#endif  /* CS_BLOB_PAGEABLE */
}
        
int
ubc_cs_blob_add(
        struct vnode    *vp,
        cpu_type_t      cputype,
        off_t           base_offset,
        vm_address_t    addr,
        vm_size_t       size)
{
        kern_return_t           kr;
        struct ubc_info         *uip;
        struct cs_blob          *blob, *oblob;
        int                     error;
        ipc_port_t              blob_handle;
        memory_object_size_t    blob_size;
        const CS_CodeDirectory *cd;
        off_t                   blob_start_offset, blob_end_offset;
        SHA1_CTX                sha1ctxt;

        blob_handle = IPC_PORT_NULL;

        blob = (struct cs_blob *) kalloc(sizeof (struct cs_blob));
        if (blob == NULL) {
                return ENOMEM;
        }

#if CS_BLOB_PAGEABLE
        /* get a memory entry on the blob */
        blob_size = (memory_object_size_t) size;
        kr = mach_make_memory_entry_64(kernel_map,
                                       &blob_size,
                                       addr,
                                       VM_PROT_READ,
                                       &blob_handle,
                                       IPC_PORT_NULL);
        if (kr != KERN_SUCCESS) {
                error = ENOMEM;
                goto out;
        }
        if (memory_object_round_page(blob_size) !=
            (memory_object_size_t) round_page(size)) {
                printf("ubc_cs_blob_add: size mismatch 0x%llx 0x%lx !?\n",
                       blob_size, (size_t)size);
                panic("XXX FBDP size mismatch 0x%llx 0x%lx\n", blob_size, (size_t)size);
                error = EINVAL;
                goto out;
        }
#else
        blob_size = (memory_object_size_t) size;
        blob_handle = IPC_PORT_NULL;
#endif

        /* fill in the new blob */
        blob->csb_cpu_type = cputype;
        blob->csb_base_offset = base_offset;
        blob->csb_mem_size = size;
        blob->csb_mem_offset = 0;
        blob->csb_mem_handle = blob_handle;
        blob->csb_mem_kaddr = addr;
        
        /*
         * Validate the blob's contents
         */
        cd = findCodeDirectory(
                (const CS_SuperBlob *) addr, 
                (char *) addr, 
                (char *) addr + blob->csb_mem_size);
        if (cd == NULL) {
                /* no code directory => useless blob ! */
                blob->csb_flags = 0;
                blob->csb_start_offset = 0;
                blob->csb_end_offset = 0;
        } else {
                const unsigned char *sha1_base;
                int sha1_size;

                blob->csb_flags = ntohl(cd->flags) | CS_VALID;
                blob->csb_end_offset = round_page(ntohl(cd->codeLimit));
                if((ntohl(cd->version) >= supportsScatter) && (ntohl(cd->scatterOffset))) {
                        const struct Scatter *scatter = (const struct Scatter*)
                                ((const char*)cd + ntohl(cd->scatterOffset));
                        blob->csb_start_offset = ntohl(scatter->base) * PAGE_SIZE;
                } else {
                        blob->csb_start_offset = (blob->csb_end_offset -
                                                  (ntohl(cd->nCodeSlots) * PAGE_SIZE));
                }
                /* compute the blob's SHA1 hash */
                sha1_base = (const unsigned char *) cd;
                sha1_size = ntohl(cd->length);
                SHA1Init(&sha1ctxt);
                SHA1Update(&sha1ctxt, sha1_base, sha1_size);
                SHA1Final(blob->csb_sha1, &sha1ctxt);
        }

        /* 
         * Let policy module check whether the blob's signature is accepted.
         */
#if CONFIG_MACF
        error = mac_vnode_check_signature(vp, blob->csb_sha1, (void*)addr, size);
        if (error) 
                goto out;
#endif  
        
        /*
         * Validate the blob's coverage
         */
        blob_start_offset = blob->csb_base_offset + blob->csb_start_offset;
        blob_end_offset = blob->csb_base_offset + blob->csb_end_offset;

        if (blob_start_offset >= blob_end_offset ||
            blob_start_offset < 0 ||
            blob_end_offset <= 0) {
                /* reject empty or backwards blob */
                error = EINVAL;
                goto out;
        }

        vnode_lock(vp);
        if (! UBCINFOEXISTS(vp)) {
                vnode_unlock(vp);
                error = ENOENT;
                goto out;
        }
        uip = vp->v_ubcinfo;

        /* check if this new blob overlaps with an existing blob */
        for (oblob = uip->cs_blobs;
             oblob != NULL;
             oblob = oblob->csb_next) {
                 off_t oblob_start_offset, oblob_end_offset;

                 oblob_start_offset = (oblob->csb_base_offset +
                                       oblob->csb_start_offset);
                 oblob_end_offset = (oblob->csb_base_offset +
                                     oblob->csb_end_offset);
                 if (blob_start_offset >= oblob_end_offset ||
                     blob_end_offset <= oblob_start_offset) {
                         /* no conflict with this existing blob */
                 } else {
                         /* conflict ! */
                         if (blob_start_offset == oblob_start_offset &&
                             blob_end_offset == oblob_end_offset &&
                             blob->csb_mem_size == oblob->csb_mem_size &&
                             blob->csb_flags == oblob->csb_flags &&
                             (blob->csb_cpu_type == CPU_TYPE_ANY ||
                              oblob->csb_cpu_type == CPU_TYPE_ANY ||
                              blob->csb_cpu_type == oblob->csb_cpu_type) &&
                             !bcmp(blob->csb_sha1,
                                   oblob->csb_sha1,
                                   SHA1_RESULTLEN)) {
                                 /*
                                  * We already have this blob:
                                  * we'll return success but
                                  * throw away the new blob.
                                  */
                                 if (oblob->csb_cpu_type == CPU_TYPE_ANY) {
                                         /*
                                          * The old blob matches this one
                                          * but doesn't have any CPU type.
                                          * Update it with whatever the caller
                                          * provided this time.
                                          */
                                         oblob->csb_cpu_type = cputype;
                                 }
                                 vnode_unlock(vp);
                                 error = EAGAIN;
                                 goto out;
                         } else {
                                 /* different blob: reject the new one */
                                 vnode_unlock(vp);
                                 error = EALREADY;
                                 goto out;
                         }
                 }

        }


        /* mark this vnode's VM object as having "signed pages" */
        kr = memory_object_signed(uip->ui_control, TRUE);
        if (kr != KERN_SUCCESS) {
                vnode_unlock(vp);
                error = ENOENT;
                goto out;
        }

        /*
         * Add this blob to the list of blobs for this vnode.
         * We always add at the front of the list and we never remove a
         * blob from the list, so ubc_cs_get_blobs() can return whatever
         * the top of the list was and that list will remain valid
         * while we validate a page, even after we release the vnode's lock.
         */
        blob->csb_next = uip->cs_blobs;
        uip->cs_blobs = blob;

        OSAddAtomic(+1, &cs_blob_count);
        if (cs_blob_count > cs_blob_count_peak) {
                cs_blob_count_peak = cs_blob_count; /* XXX atomic ? */
        }
        OSAddAtomic((SInt32) +blob->csb_mem_size, &cs_blob_size);
        if ((SInt32) cs_blob_size > cs_blob_size_peak) {
                cs_blob_size_peak = (SInt32) cs_blob_size; /* XXX atomic ? */
        }
        if ((UInt32) blob->csb_mem_size > cs_blob_size_max) {
                cs_blob_size_max = (UInt32) blob->csb_mem_size;
        }

        if (cs_debug > 1) {
                proc_t p;

                p = current_proc();
                printf("CODE SIGNING: proc %d(%s) "
                       "loaded %s signatures for file (%s) "
                       "range 0x%llx:0x%llx flags 0x%x\n",
                       p->p_pid, p->p_comm,
                       blob->csb_cpu_type == -1 ? "detached" : "embedded",
                       vnode_name(vp),
                       blob->csb_base_offset + blob->csb_start_offset,
                       blob->csb_base_offset + blob->csb_end_offset,
                       blob->csb_flags);
        }

        vnode_unlock(vp);

        error = 0;      /* success ! */

out:
        if (error) {
                /* we failed; release what we allocated */
                if (blob) {
                        kfree(blob, sizeof (*blob));
                        blob = NULL;
                }
                if (blob_handle != IPC_PORT_NULL) {
                        mach_memory_entry_port_release(blob_handle);
                        blob_handle = IPC_PORT_NULL;
                }
        }

        if (error == EAGAIN) {
                /*
                 * See above:  error is EAGAIN if we were asked 
                 * to add an existing blob again.  We cleaned the new
                 * blob and we want to return success.
                 */
                error = 0;
                /*
                 * Since we're not failing, consume the data we received.
                 */
                ubc_cs_blob_deallocate(addr, size);
        }

        return error;
}


struct cs_blob *
ubc_cs_blob_get(
        struct vnode    *vp,
        cpu_type_t      cputype,
        off_t           offset)
{
        struct ubc_info *uip;
        struct cs_blob  *blob;
        off_t offset_in_blob;

        vnode_lock_spin(vp);

        if (! UBCINFOEXISTS(vp)) {
                blob = NULL;
                goto out;
        }

        uip = vp->v_ubcinfo;
        for (blob = uip->cs_blobs;
             blob != NULL;
             blob = blob->csb_next) {
                if (cputype != -1 && blob->csb_cpu_type == cputype) {
                        break;
                }
                if (offset != -1) {
                        offset_in_blob = offset - blob->csb_base_offset;
                        if (offset_in_blob >= blob->csb_start_offset &&
                            offset_in_blob < blob->csb_end_offset) {
                                /* our offset is covered by this blob */
                                break;
                        }
                }
        }

out:
        vnode_unlock(vp);

        return blob;
}

static void
ubc_cs_free(
        struct ubc_info *uip)
{
        struct cs_blob  *blob, *next_blob;

        for (blob = uip->cs_blobs;
             blob != NULL;
             blob = next_blob) {
                next_blob = blob->csb_next;
                if (blob->csb_mem_kaddr != 0) {
                        ubc_cs_blob_deallocate(blob->csb_mem_kaddr,
                                               blob->csb_mem_size);
                        blob->csb_mem_kaddr = 0;
                }
                if (blob->csb_mem_handle != IPC_PORT_NULL) {
                        mach_memory_entry_port_release(blob->csb_mem_handle);
                }
                blob->csb_mem_handle = IPC_PORT_NULL;
                OSAddAtomic(-1, &cs_blob_count);
                OSAddAtomic((SInt32) -blob->csb_mem_size, &cs_blob_size);
                kfree(blob, sizeof (*blob));
        }
#if CHECK_CS_VALIDATION_BITMAP
        ubc_cs_validation_bitmap_deallocate( uip->ui_vnode );
#endif
        uip->cs_blobs = NULL;
}

struct cs_blob *
ubc_get_cs_blobs(
        struct vnode    *vp)
{
        struct ubc_info *uip;
        struct cs_blob  *blobs;

        /*
         * No need to take the vnode lock here.  The caller must be holding
         * a reference on the vnode (via a VM mapping or open file descriptor),
         * so the vnode will not go away.  The ubc_info stays until the vnode
         * goes away.  And we only modify "blobs" by adding to the head of the
         * list.
         * The ubc_info could go away entirely if the vnode gets reclaimed as
         * part of a forced unmount.  In the case of a code-signature validation
         * during a page fault, the "paging_in_progress" reference on the VM
         * object guarantess that the vnode pager (and the ubc_info) won't go
         * away during the fault.
         * Other callers need to protect against vnode reclaim by holding the
         * vnode lock, for example.
         */

        if (! UBCINFOEXISTS(vp)) {
                blobs = NULL;
                goto out;
        }

        uip = vp->v_ubcinfo;
        blobs = uip->cs_blobs;

out:
        return blobs;
}

unsigned long cs_validate_page_no_hash = 0;
unsigned long cs_validate_page_bad_hash = 0;
boolean_t
cs_validate_page(
        void                    *_blobs,
        memory_object_t         pager,
        memory_object_offset_t  page_offset,
        const void              *data,
        boolean_t               *tainted)
{
        SHA1_CTX                sha1ctxt;
        unsigned char           actual_hash[SHA1_RESULTLEN];
        unsigned char           expected_hash[SHA1_RESULTLEN];
        boolean_t               found_hash;
        struct cs_blob          *blobs, *blob;
        const CS_CodeDirectory  *cd;
        const CS_SuperBlob      *embedded;
        const unsigned char     *hash;
        boolean_t               validated;
        off_t                   offset; /* page offset in the file */
        size_t                  size;
        off_t                   codeLimit = 0;
        char                    *lower_bound, *upper_bound;
        vm_offset_t             kaddr, blob_addr;
        vm_size_t               ksize;
        kern_return_t           kr;

        offset = page_offset;

        /* retrieve the expected hash */
        found_hash = FALSE;
        blobs = (struct cs_blob *) _blobs;

        for (blob = blobs;
             blob != NULL;
             blob = blob->csb_next) {
                offset = page_offset - blob->csb_base_offset;
                if (offset < blob->csb_start_offset ||
                    offset >= blob->csb_end_offset) {
                        /* our page is not covered by this blob */
                        continue;
                }

                /* map the blob in the kernel address space */
                kaddr = blob->csb_mem_kaddr;
                if (kaddr == 0) {
                        ksize = (vm_size_t) (blob->csb_mem_size +
                                             blob->csb_mem_offset);
                        kr = vm_map(kernel_map,
                                    &kaddr,
                                    ksize,
                                    0,
                                    VM_FLAGS_ANYWHERE,
                                    blob->csb_mem_handle,
                                    0,
                                    TRUE,
                                    VM_PROT_READ,
                                    VM_PROT_READ,
                                    VM_INHERIT_NONE);
                        if (kr != KERN_SUCCESS) {
                                /* XXX FBDP what to do !? */
                                printf("cs_validate_page: failed to map blob, "
                                       "size=0x%lx kr=0x%x\n",
                                       (size_t)blob->csb_mem_size, kr);
                                break;
                        }
                }
                blob_addr = kaddr + blob->csb_mem_offset;
                
                lower_bound = CAST_DOWN(char *, blob_addr);
                upper_bound = lower_bound + blob->csb_mem_size;

                embedded = (const CS_SuperBlob *) blob_addr;
                cd = findCodeDirectory(embedded, lower_bound, upper_bound);
                if (cd != NULL) {
                        if (cd->pageSize != PAGE_SHIFT ||
                            cd->hashType != 0x1 ||
                            cd->hashSize != SHA1_RESULTLEN) {
                                /* bogus blob ? */
                                continue;
                        }

                        offset = page_offset - blob->csb_base_offset;
                        if (offset < blob->csb_start_offset ||
                            offset >= blob->csb_end_offset) {
                                /* our page is not covered by this blob */
                                continue;
                        }

                        codeLimit = ntohl(cd->codeLimit);
                        hash = hashes(cd, atop(offset),
                                      lower_bound, upper_bound);
                        if (hash != NULL) {
                                bcopy(hash, expected_hash,
                                      sizeof (expected_hash));
                                found_hash = TRUE;
                        }

                        break;
                }
        }

        if (found_hash == FALSE) {
                /*
                 * We can't verify this page because there is no signature
                 * for it (yet).  It's possible that this part of the object
                 * is not signed, or that signatures for that part have not
                 * been loaded yet.
                 * Report that the page has not been validated and let the
                 * caller decide if it wants to accept it or not.
                 */
                cs_validate_page_no_hash++;
                if (cs_debug > 1) {
                        printf("CODE SIGNING: cs_validate_page: "
                               "mobj %p off 0x%llx: no hash to validate !?\n",
                               pager, page_offset);
                }
                validated = FALSE;
                *tainted = FALSE;
        } else {

                size = PAGE_SIZE;
                const uint32_t *asha1, *esha1;
                if ((off_t)(offset + size) > codeLimit) {
                        /* partial page at end of segment */
                        assert(offset < codeLimit);
                        size = (size_t) (codeLimit & PAGE_MASK);
                }
                /* compute the actual page's SHA1 hash */
                SHA1Init(&sha1ctxt);
                SHA1UpdateUsePhysicalAddress(&sha1ctxt, data, size);
                SHA1Final(actual_hash, &sha1ctxt);

                asha1 = (const uint32_t *) actual_hash;
                esha1 = (const uint32_t *) expected_hash;

                if (bcmp(expected_hash, actual_hash, SHA1_RESULTLEN) != 0) {
                        if (cs_debug) {
                                printf("CODE SIGNING: cs_validate_page: "
                                       "mobj %p off 0x%llx size 0x%lx: "
                                       "actual [0x%x 0x%x 0x%x 0x%x 0x%x] != "
                                       "expected [0x%x 0x%x 0x%x 0x%x 0x%x]\n",
                                       pager, page_offset, size,
                                       asha1[0], asha1[1], asha1[2],
                                       asha1[3], asha1[4],
                                       esha1[0], esha1[1], esha1[2],
                                       esha1[3], esha1[4]);
                        }
                        cs_validate_page_bad_hash++;
                        *tainted = TRUE;
                } else {
                        if (cs_debug > 1) {
                                printf("CODE SIGNING: cs_validate_page: "
                                       "mobj %p off 0x%llx size 0x%lx: "
                                       "SHA1 OK\n",
                                       pager, page_offset, size);
                        }
                        *tainted = FALSE;
                }
                validated = TRUE;
        }
        
        return validated;
}

int
ubc_cs_getcdhash(
        vnode_t         vp,
        off_t           offset,
        unsigned char   *cdhash)
{
        struct cs_blob  *blobs, *blob;
        off_t           rel_offset;
        int             ret;

        vnode_lock(vp);

        blobs = ubc_get_cs_blobs(vp);
        for (blob = blobs;
             blob != NULL;
             blob = blob->csb_next) {
                /* compute offset relative to this blob */
                rel_offset = offset - blob->csb_base_offset;
                if (rel_offset >= blob->csb_start_offset &&
                    rel_offset < blob->csb_end_offset) {
                        /* this blob does cover our "offset" ! */
                        break;
                }
        }

        if (blob == NULL) {
                /* we didn't find a blob covering "offset" */
                ret = EBADEXEC; /* XXX any better error ? */
        } else {
                /* get the SHA1 hash of that blob */
                bcopy(blob->csb_sha1, cdhash, sizeof (blob->csb_sha1));
                ret = 0;
        }

        vnode_unlock(vp);

        return ret;
}

#if CHECK_CS_VALIDATION_BITMAP
#define stob(s) ((atop_64((s)) + 07) >> 3)
extern  boolean_t       root_fs_upgrade_try;

/*
 * Should we use the code-sign bitmap to avoid repeated code-sign validation?
 * Depends:
 * a) Is the target vnode on the root filesystem?
 * b) Has someone tried to mount the root filesystem read-write?
 * If answers are (a) yes AND (b) no, then we can use the bitmap.
 */
#define USE_CODE_SIGN_BITMAP(vp)        ( (vp != NULL) && (vp->v_mount != NULL) && (vp->v_mount->mnt_flag & MNT_ROOTFS) && !root_fs_upgrade_try) 
kern_return_t
ubc_cs_validation_bitmap_allocate(
        vnode_t         vp)
{
        kern_return_t   kr = KERN_SUCCESS;
        struct ubc_info *uip;
        char            *target_bitmap;
        vm_object_size_t        bitmap_size;

        if ( ! USE_CODE_SIGN_BITMAP(vp) || (! UBCINFOEXISTS(vp))) {
                kr = KERN_INVALID_ARGUMENT;
        } else {
                uip = vp->v_ubcinfo;

                if ( uip->cs_valid_bitmap == NULL ) {
                        bitmap_size = stob(uip->ui_size);
                        target_bitmap = (char*) kalloc( (vm_size_t)bitmap_size );
                        if (target_bitmap == 0) {
                                kr = KERN_NO_SPACE;
                        } else {
                                kr = KERN_SUCCESS;
                        }
                        if( kr == KERN_SUCCESS ) {
                                memset( target_bitmap, 0, (size_t)bitmap_size);
                                uip->cs_valid_bitmap = (void*)target_bitmap;
                                uip->cs_valid_bitmap_size = bitmap_size;
                        }
                }
        }
        return kr;
}

kern_return_t
ubc_cs_check_validation_bitmap (
        vnode_t                 vp,
        memory_object_offset_t          offset,
        int                     optype)
{
        kern_return_t   kr = KERN_SUCCESS;

        if ( ! USE_CODE_SIGN_BITMAP(vp) || ! UBCINFOEXISTS(vp)) {
                kr = KERN_INVALID_ARGUMENT;
        } else {
                struct ubc_info *uip = vp->v_ubcinfo;
                char            *target_bitmap = uip->cs_valid_bitmap;

                if ( target_bitmap == NULL ) {
                       kr = KERN_INVALID_ARGUMENT;
                } else {
                        uint64_t        bit, byte;
                        bit = atop_64( offset );
                        byte = bit >> 3;

                        if ( byte > uip->cs_valid_bitmap_size ) {
                               kr = KERN_INVALID_ARGUMENT;
                        } else {

                                if (optype == CS_BITMAP_SET) {
                                        target_bitmap[byte] |= (1 << (bit & 07));
                                        kr = KERN_SUCCESS;
                                } else if (optype == CS_BITMAP_CLEAR) {
                                        target_bitmap[byte] &= ~(1 << (bit & 07));
                                        kr = KERN_SUCCESS;
                                } else if (optype == CS_BITMAP_CHECK) {
                                        if ( target_bitmap[byte] & (1 << (bit & 07))) {
                                                kr = KERN_SUCCESS;
                                        } else {
                                                kr = KERN_FAILURE;
                                        }
                                }
                        }
                }
        }
        return kr;
}

void
ubc_cs_validation_bitmap_deallocate(
        vnode_t         vp)
{
        struct ubc_info *uip;
        void            *target_bitmap;
        vm_object_size_t        bitmap_size;

        if ( UBCINFOEXISTS(vp)) {
                uip = vp->v_ubcinfo;

                if ( (target_bitmap = uip->cs_valid_bitmap) != NULL ) {
                        bitmap_size = uip->cs_valid_bitmap_size;
                        kfree( target_bitmap, (vm_size_t) bitmap_size );
                        uip->cs_valid_bitmap = NULL;
                }
        }
}
#else
kern_return_t   ubc_cs_validation_bitmap_allocate(__unused vnode_t vp){
        return KERN_INVALID_ARGUMENT;
}

kern_return_t ubc_cs_check_validation_bitmap(
        __unused struct vnode *vp, 
        __unused memory_object_offset_t offset,
        __unused int optype){

        return KERN_INVALID_ARGUMENT;
}

void    ubc_cs_validation_bitmap_deallocate(__unused vnode_t vp){
        return;
}
#endif /* CHECK_CS_VALIDATION_BITMAP */