kmod.c   [plain text]

/*
 * Copyright (c) 2000-2004 Apple Computer, Inc. All rights reserved.
 *
 * @APPLE_LICENSE_HEADER_START@
 * 
 * The contents of this file constitute Original Code as defined in and
 * are subject to the Apple Public Source License Version 1.1 (the
 * "License").  You may not use this file except in compliance with the
 * License.  Please obtain a copy of the License at
 * http://www.apple.com/publicsource and read it before using this file.
 * 
 * This 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 OR NON-INFRINGEMENT.  Please see the
 * License for the specific language governing rights and limitations
 * under the License.
 * 
 * @APPLE_LICENSE_HEADER_END@
 */
/*
 * Copyright (c) 1999 Apple Computer, Inc.  All rights reserved. 
 *
 * HISTORY
 *
 * 1999 Mar 29 rsulack created.
 */

#include <mach/mach_types.h>
#include <mach/vm_types.h>
#include <mach/kern_return.h>
#include <mach/host_priv_server.h>
#include <mach/vm_map.h>

#include <kern/kalloc.h>
#include <kern/kern_types.h>
#include <kern/thread.h>

#include <vm/vm_kern.h>

#include <mach-o/mach_header.h>

#include <mach_host.h>

/*
 * XXX headers for which prototypes should be in a common include file;
 * XXX see libsa/kext.cpp for why.
 */
kern_return_t	kmod_create_internal(kmod_info_t *info, kmod_t *id);
kern_return_t	kmod_destroy_internal(kmod_t id);
kern_return_t	kmod_start_or_stop(kmod_t id, int start, kmod_args_t *data,
			mach_msg_type_number_t *dataCount);
kern_return_t	kmod_retain(kmod_t id);
kern_return_t	kmod_release(kmod_t id);
kern_return_t	kmod_queue_cmd(vm_address_t data, vm_size_t size);
kern_return_t	kmod_get_info(host_t host, kmod_info_array_t *kmods,
			mach_msg_type_number_t *kmodCount);
extern void	kdb_printf(const char *fmt, ...);



#define WRITE_PROTECT_MODULE_TEXT   (0)

kmod_info_t *kmod = 0;
static int kmod_index = 1;

decl_simple_lock_data(,kmod_lock)
decl_simple_lock_data(,kmod_queue_lock)

typedef struct cmd_queue_entry {
    queue_chain_t    links;
    vm_address_t     data;
    vm_size_t        size;
} cmd_queue_entry_t;

queue_head_t kmod_cmd_queue;

void
kmod_init(void)
{
    simple_lock_init(&kmod_lock, 0);
    simple_lock_init(&kmod_queue_lock, 0);
    queue_init(&kmod_cmd_queue);
}

kmod_info_t *
kmod_lookupbyid(kmod_t id)
{
    kmod_info_t *k = 0;

    k = kmod;
    while (k) {
        if (k->id == id) break;
        k = k->next;
    }

    return k;
}

kmod_info_t *
kmod_lookupbyname(const char * name)
{
    kmod_info_t *k = 0;

    k = kmod;
    while (k) {
        if (!strcmp(k->name, name)) break;
        k = k->next;
    }

    return k;
}

kmod_info_t *
kmod_lookupbyid_locked(kmod_t id)
{
    kmod_info_t *k = 0;
    kmod_info_t *kc = 0;

    kc = (kmod_info_t *)kalloc(sizeof(kmod_info_t));
    if (!kc) return kc;

    simple_lock(&kmod_queue_lock);
    k = kmod_lookupbyid(id);
    if (k) {
        bcopy((char*)k, (char *)kc, sizeof(kmod_info_t));
    }

    simple_unlock(&kmod_queue_lock);

    if (k == 0) {
        kfree(kc, sizeof(kmod_info_t));
	kc = 0;
    }
    return kc;
}

kmod_info_t *
kmod_lookupbyname_locked(const char * name)
{
    kmod_info_t *k = 0;
    kmod_info_t *kc = 0;

    kc = (kmod_info_t *)kalloc(sizeof(kmod_info_t));
    if (!kc) return kc;

    simple_lock(&kmod_queue_lock);
    k = kmod_lookupbyname(name);
    if (k) {
        bcopy((char *)k, (char *)kc, sizeof(kmod_info_t));
    }

    simple_unlock(&kmod_queue_lock);

    if (k == 0) {
        kfree(kc, sizeof(kmod_info_t));
	kc = 0;
    }
    return kc;
}

// XXX add a nocopy flag??

kern_return_t
kmod_queue_cmd(vm_address_t data, vm_size_t size)
{
    kern_return_t rc;
    cmd_queue_entry_t *e = (cmd_queue_entry_t *)kalloc(sizeof(struct cmd_queue_entry));
    if (!e) return KERN_RESOURCE_SHORTAGE;

    rc = kmem_alloc(kernel_map, &e->data, size);
    if (rc != KERN_SUCCESS) {
        kfree(e, sizeof(struct cmd_queue_entry));
        return rc;
    }
    e->size = size;
    bcopy((void *)data, (void *)e->data, size);

    simple_lock(&kmod_queue_lock);
    enqueue_tail(&kmod_cmd_queue, (queue_entry_t)e);
    simple_unlock(&kmod_queue_lock);

    thread_wakeup_one((event_t)&kmod_cmd_queue);
    
    return KERN_SUCCESS;
}

kern_return_t
kmod_load_extension(char *name)
{
    kmod_load_extension_cmd_t    *data;
    vm_size_t            size;

    size = sizeof(kmod_load_extension_cmd_t);
    data = (kmod_load_extension_cmd_t *)kalloc(size);
    if (!data) return KERN_RESOURCE_SHORTAGE;

    data->type = KMOD_LOAD_EXTENSION_PACKET;
    strncpy(data->name, name, KMOD_MAX_NAME);

    return kmod_queue_cmd((vm_address_t)data, size);
}

kern_return_t
kmod_load_extension_with_dependencies(char *name, char **dependencies)
{
    kmod_load_with_dependencies_cmd_t *data;
    vm_size_t    size;
    char        **c;
    int         i, count = 0;

    c = dependencies;
    if (c) {
        while (*c) {
            count++; c++;
        }
    }
    size = sizeof(int) + KMOD_MAX_NAME * (count + 1) + 1; 
    data = (kmod_load_with_dependencies_cmd_t *)kalloc(size);
    if (!data) return KERN_RESOURCE_SHORTAGE;

    data->type = KMOD_LOAD_WITH_DEPENDENCIES_PACKET;
    strncpy(data->name, name, KMOD_MAX_NAME);

    c = dependencies;
    for (i=0; i < count; i++) {
        strncpy(data->dependencies[i], *c, KMOD_MAX_NAME);
        c++;
    }
    data->dependencies[count][0] = 0;

    return kmod_queue_cmd((vm_address_t)data, size);
}
kern_return_t
kmod_send_generic(int type, void *generic_data, int size)
{
    kmod_generic_cmd_t    *data;

    data = (kmod_generic_cmd_t *)kalloc(size + sizeof(int));
    if (!data) return KERN_RESOURCE_SHORTAGE;

    data->type = type;
    bcopy(data->data, generic_data, size);

    return kmod_queue_cmd((vm_address_t)data, size + sizeof(int));
}

extern vm_offset_t sectPRELINKB;
extern int sectSizePRELINK;

/*
 * Operates only on 32 bit mach keaders on behalf of kernel module loader
 * if WRITE_PROTECT_MODULE_TEXT is defined.
 */
kern_return_t
kmod_create_internal(kmod_info_t *info, kmod_t *id)
{
    kern_return_t rc;
    boolean_t     isPrelink;

    if (!info) return KERN_INVALID_ADDRESS;

    // double check for page alignment
    if ((info->address | info->hdr_size) & (PAGE_SIZE - 1)) {
        return KERN_INVALID_ADDRESS;
    }

    isPrelink = ((info->address >= sectPRELINKB) && (info->address < (sectPRELINKB + sectSizePRELINK)));
    if (!isPrelink) {
	rc = vm_map_wire(kernel_map, info->address + info->hdr_size, 
		info->address + info->size, VM_PROT_DEFAULT, FALSE);
	if (rc != KERN_SUCCESS) {
	    return rc;
	}
    }
#if WRITE_PROTECT_MODULE_TEXT
     {
	struct section * sect = getsectbynamefromheader(
	    (struct mach_header*) info->address, "__TEXT", "__text");
	
	if(sect) {
	    (void) vm_map_protect(kernel_map, round_page(sect->addr), trunc_page(sect->addr + sect->size),
				    VM_PROT_READ|VM_PROT_EXECUTE, TRUE);
	}
    }
#endif /* WRITE_PROTECT_MODULE_TEXT */

    simple_lock(&kmod_lock);

    // check to see if already loaded
    if (kmod_lookupbyname(info->name)) {
        simple_unlock(&kmod_lock);
	if (!isPrelink) {
	    rc = vm_map_unwire(kernel_map, info->address + info->hdr_size, 
		info->address + info->size, FALSE);
	    assert(rc == KERN_SUCCESS);
	}
        return KERN_INVALID_ARGUMENT;
    }

    info->id = kmod_index++;
    info->reference_count = 0;

    info->next = kmod;
    kmod = info;

    *id = info->id;

    simple_unlock(&kmod_lock);

#if DEBUG
    printf("kmod_create: %s (id %d), %d pages loaded at 0x%x, header size 0x%x\n", 
        info->name, info->id, info->size / PAGE_SIZE, info->address, info->hdr_size);
#endif /* DEBUG */

    return KERN_SUCCESS;
}


kern_return_t
kmod_create(host_priv_t host_priv,
        vm_address_t addr,
        kmod_t *id)
{
    kmod_info_t *info = (kmod_info_t *)addr;
 
    if (host_priv == HOST_PRIV_NULL) return KERN_INVALID_HOST;
    return kmod_create_internal(info, id);
}

kern_return_t
kmod_create_fake_with_address(const char *name, const char *version, 
                                vm_address_t address, vm_size_t size,
                                int * return_id)
{
    kmod_info_t *info;

    if (!name || ! version || 
        (1 + strlen(name) > KMOD_MAX_NAME) ||
        (1 + strlen(version) > KMOD_MAX_NAME)) {

        return KERN_INVALID_ARGUMENT;
    }
 
    info = (kmod_info_t *)kalloc(sizeof(kmod_info_t));
    if (!info) {
        return KERN_RESOURCE_SHORTAGE;
    }

    // make de fake
    info->info_version = KMOD_INFO_VERSION;
    bcopy(name, info->name, 1 + strlen(name));
    bcopy(version, info->version, 1 + strlen(version));  //NIK fixed this part
    info->reference_count = 1;    // keep it from unloading, starting, stopping
    info->reference_list = 0;
    info->address = address;
    info->size = size;
    info->hdr_size = 0;
    info->start = info->stop = 0;

    simple_lock(&kmod_lock);

    // check to see if already "loaded"
    if (kmod_lookupbyname(info->name)) {
        simple_unlock(&kmod_lock);
        return KERN_INVALID_ARGUMENT;
    }

    info->id = kmod_index++;
    if (return_id)
        *return_id = info->id;

    info->next = kmod;
    kmod = info;

    simple_unlock(&kmod_lock);

    return KERN_SUCCESS;
}

kern_return_t
kmod_create_fake(const char *name, const char *version)
{
    return kmod_create_fake_with_address(name, version, 0, 0, NULL);
}


static kern_return_t
_kmod_destroy_internal(kmod_t id, boolean_t fake)
{
    kern_return_t rc;
    kmod_info_t *k;
    kmod_info_t *p;

    simple_lock(&kmod_lock);

    k = p = kmod;
    while (k) {
        if (k->id == id) {
            kmod_reference_t *r, *t;

            if (!fake && (k->reference_count != 0)) {
                simple_unlock(&kmod_lock);
                return KERN_INVALID_ARGUMENT;
            }
                
            if (k == p) {    // first element
                kmod = k->next;
            } else {
                p->next = k->next;
            }
            simple_unlock(&kmod_lock);

            r = k->reference_list;
            while (r) {
                r->info->reference_count--;
                t = r;
                r = r->next;
                kfree(t, sizeof(struct kmod_reference));
            }

            if (!fake)
            {
#if DEBUG
                printf("kmod_destroy: %s (id %d), deallocating %d pages starting at 0x%x\n", 
                    k->name, k->id, k->size / PAGE_SIZE, k->address);
#endif /* DEBUG */

                if( (k->address >= sectPRELINKB) && (k->address < (sectPRELINKB + sectSizePRELINK)))
                {
                    vm_offset_t
                    virt = ml_static_ptovirt(k->address);
                    if( virt) {
                        ml_static_mfree( virt, k->size);
                    }
                }
                else
                {
                    rc = vm_map_unwire(kernel_map, k->address + k->hdr_size, 
                            k->address + k->size, FALSE);
                    assert(rc == KERN_SUCCESS);
        
                    rc = vm_deallocate(kernel_map, k->address, k->size);
                    assert(rc == KERN_SUCCESS);
                }
            }
            return KERN_SUCCESS;
        }
        p = k;
        k = k->next;
    }

    simple_unlock(&kmod_lock);

    return KERN_INVALID_ARGUMENT;
}

kern_return_t
kmod_destroy_internal(kmod_t id)
{
    return _kmod_destroy_internal(id, FALSE);
}

kern_return_t
kmod_destroy(host_priv_t host_priv,
         kmod_t id)
{
    if (host_priv == HOST_PRIV_NULL) return KERN_INVALID_HOST;
    return _kmod_destroy_internal(id, FALSE);
}

kern_return_t
kmod_destroy_fake(kmod_t id)
{
    return _kmod_destroy_internal(id, TRUE);
}

kern_return_t
kmod_start_or_stop(
    kmod_t id,
    int start,
    kmod_args_t *data,
    mach_msg_type_number_t *dataCount)
{
    kern_return_t rc = KERN_SUCCESS;
    void * user_data = 0;
    kern_return_t (*func)(kmod_info_t *, void *);
    kmod_info_t *k;

    simple_lock(&kmod_lock);

    k = kmod_lookupbyid(id);
    if (!k || k->reference_count) {
        simple_unlock(&kmod_lock);
        rc = KERN_INVALID_ARGUMENT;
        goto finish;
    }

    if (start) {
        func = (void *)k->start;
    } else {
        func = (void *)k->stop;
    }

    simple_unlock(&kmod_lock);

    //
    // call kmod entry point
    //
    if (data && dataCount && *data && *dataCount) {
    	vm_map_offset_t map_addr;
        vm_map_copyout(kernel_map, &map_addr, (vm_map_copy_t)*data);
	user_data = CAST_DOWN(void *, map_addr);
    }

    rc = (*func)(k, user_data);

finish:

    if (user_data) {
        (void) vm_deallocate(kernel_map, (vm_offset_t)user_data, *dataCount);
    }
    if (data) *data = 0;
    if (dataCount) *dataCount = 0;

    return rc;
}


/*
 * The retain and release calls take no user data, but the caller
 * may have sent some in error (the MIG definition allows it).
 * If this is the case, they will just return that same data
 * right back to the caller (since they never touch the *data and
 * *dataCount fields).
 */
kern_return_t
kmod_retain(kmod_t id)
{
    kern_return_t rc = KERN_SUCCESS;

    kmod_info_t *t;    // reference to
    kmod_info_t *f;    // reference from
    kmod_reference_t *r = 0;

    r = (kmod_reference_t *)kalloc(sizeof(struct kmod_reference));
    if (!r) {
        rc = KERN_RESOURCE_SHORTAGE;
        goto finish;
    }

    simple_lock(&kmod_lock);

    t = kmod_lookupbyid(KMOD_UNPACK_TO_ID(id));
    f = kmod_lookupbyid(KMOD_UNPACK_FROM_ID(id));
    if (!t || !f) {
        simple_unlock(&kmod_lock);
        if (r) kfree(r, sizeof(struct kmod_reference));
        rc = KERN_INVALID_ARGUMENT;
        goto finish;
    }

    r->next = f->reference_list;
    r->info = t;
    f->reference_list = r;
    t->reference_count++;

    simple_unlock(&kmod_lock);

finish:

    return rc;
}


kern_return_t
kmod_release(kmod_t id)
{
    kern_return_t rc = KERN_INVALID_ARGUMENT;

    kmod_info_t *t;    // reference to
    kmod_info_t *f;    // reference from
    kmod_reference_t *r = 0;
    kmod_reference_t * p;

    simple_lock(&kmod_lock);

    t = kmod_lookupbyid(KMOD_UNPACK_TO_ID(id));
    f = kmod_lookupbyid(KMOD_UNPACK_FROM_ID(id));
    if (!t || !f) {
        rc = KERN_INVALID_ARGUMENT;
        goto finish;
    }

    p = r = f->reference_list;
    while (r) {
        if (r->info == t) {
            if (p == r) {    // first element
                f->reference_list = r->next;
            } else {
                p->next = r->next;
            }
            r->info->reference_count--;

        simple_unlock(&kmod_lock);
            kfree(r, sizeof(struct kmod_reference));
        rc = KERN_SUCCESS;
            goto finish;
        }
        p = r;
        r = r->next;
    }

    simple_unlock(&kmod_lock);

finish:

    return rc;
}


kern_return_t
kmod_control(host_priv_t host_priv,
         kmod_t id,
         kmod_control_flavor_t flavor,
         kmod_args_t *data,
         mach_msg_type_number_t *dataCount)
{
    kern_return_t rc = KERN_SUCCESS;

    if (host_priv == HOST_PRIV_NULL) return KERN_INVALID_HOST;

    switch (flavor) {

      case KMOD_CNTL_START:
      case KMOD_CNTL_STOP:
        {
            rc = kmod_start_or_stop(id, (flavor == KMOD_CNTL_START),
                data, dataCount);
            break;
        }

      case KMOD_CNTL_RETAIN:
        {
            rc = kmod_retain(id);
            break;
        }

      case KMOD_CNTL_RELEASE:
        {
            rc = kmod_release(id);
            break;
        }

      case KMOD_CNTL_GET_CMD:
        {

            cmd_queue_entry_t *e;

            /*
             * Throw away any data the user may have sent in error.
             * We must do this, because we are likely to return to
             * some data for these commands (thus causing a leak of
             * whatever data the user sent us in error).
             */
            if (*data && *dataCount) {
                vm_map_copy_discard(*data);
                *data = 0;
                *dataCount = 0;
            }
            
            simple_lock(&kmod_queue_lock);

            if (queue_empty(&kmod_cmd_queue)) {
                wait_result_t res;

                res = thread_sleep_simple_lock((event_t)&kmod_cmd_queue,
                                   &kmod_queue_lock,
                                   THREAD_ABORTSAFE);
                if (queue_empty(&kmod_cmd_queue)) {
                    // we must have been interrupted!
                    simple_unlock(&kmod_queue_lock);
                    assert(res == THREAD_INTERRUPTED);
                    return KERN_ABORTED;
                }
            }
            e = (cmd_queue_entry_t *)dequeue_head(&kmod_cmd_queue);

            simple_unlock(&kmod_queue_lock);

            rc = vm_map_copyin(kernel_map, (vm_map_address_t)e->data,
			       (vm_map_size_t)e->size, TRUE, (vm_map_copy_t *)data);
            if (rc) {
                simple_lock(&kmod_queue_lock);
                enqueue_head(&kmod_cmd_queue, (queue_entry_t)e);
                simple_unlock(&kmod_queue_lock);
                *data = 0;
                *dataCount = 0;
                return rc;
            }
            *dataCount = e->size;

            kfree(e, sizeof(struct cmd_queue_entry));
        
            break;
        }

      default:
        rc = KERN_INVALID_ARGUMENT;
    }

    return rc;
};


kern_return_t
kmod_get_info(__unused host_t host,
          kmod_info_array_t *kmods,
          mach_msg_type_number_t *kmodCount)
{
    vm_offset_t data;
    kmod_info_t *k, *p1;
    kmod_reference_t *r, *p2;
    int ref_count;
    unsigned size = 0;
    kern_return_t rc = KERN_SUCCESS;

    *kmods = (void *)0;
    *kmodCount = 0;

retry:
    simple_lock(&kmod_lock);
    size = 0;
    k = kmod;
    while (k) {
        size += sizeof(kmod_info_t);
        r = k->reference_list;
        while (r) {
            size +=sizeof(kmod_reference_t);
            r = r->next;
        }
        k = k->next;
    }
    simple_unlock(&kmod_lock);
    if (!size) return KERN_SUCCESS;

    rc = kmem_alloc(kernel_map, &data, size);
    if (rc) return rc;

    // copy kmod into data, retry if kmod's size has changed (grown)
    // the copied out data is tweeked to figure what's what at user level
    // change the copied out k->next pointers to point to themselves
    // change the k->reference into a count, tack the references on
    // the end of the data packet in the order they are found

    simple_lock(&kmod_lock);
    k = kmod; p1 = (kmod_info_t *)data;
    while (k) {
        if ((p1 + 1) > (kmod_info_t *)(data + size)) {
            simple_unlock(&kmod_lock);
            kmem_free(kernel_map, data, size);
            goto retry;
        }

        *p1 = *k;
        if (k->next) p1->next = k;
        p1++; k = k->next;
    }

    p2 = (kmod_reference_t *)p1;
    k = kmod; p1 = (kmod_info_t *)data;
    while (k) {
        r = k->reference_list; ref_count = 0;
        while (r) {
            if ((p2 + 1) > (kmod_reference_t *)(data + size)) {
                simple_unlock(&kmod_lock);
                kmem_free(kernel_map, data, size);
                goto retry;
            }
            // note the last 'k' in the chain has its next == 0
            // since there can only be one like that, 
            // this case is handled by the caller
            *p2 = *r;
            p2++; r = r->next; ref_count++;
        }
        p1->reference_list = (kmod_reference_t *)ref_count;
        p1++; k = k->next;
    }
    simple_unlock(&kmod_lock);
    
    rc = vm_map_copyin(kernel_map, data, size, TRUE, (vm_map_copy_t *)kmods);
    if (rc) {
        kmem_free(kernel_map, data, size);
        *kmods = 0;
        *kmodCount = 0;
        return rc;
    }
    *kmodCount = size;

    return KERN_SUCCESS;
}

/*
 * Operates only on 32 bit mach keaders on behalf of kernel module loader
 */
static kern_return_t
kmod_call_funcs_in_section(struct mach_header *header, const char *sectName)
{
    typedef void (*Routine)(void);
    Routine *     routines;
    int           size, i;

    if (header->magic != MH_MAGIC) {
        return KERN_INVALID_ARGUMENT;
    }

    routines = (Routine *) getsectdatafromheader(header, SEG_TEXT, /*(char *)*/ sectName, &size);
    if (!routines) return KERN_SUCCESS;

    size /= sizeof(Routine);
    for (i = 0; i < size; i++) {
        (*routines[i])();
    }

    return KERN_SUCCESS;
}

/*
 * Operates only on 32 bit mach keaders on behalf of kernel module loader
 */
kern_return_t
kmod_initialize_cpp(kmod_info_t *info)
{
    return kmod_call_funcs_in_section((struct mach_header *)info->address, "__constructor");
}

/*
 * Operates only on 32 bit mach keaders on behalf of kernel module loader
 */
kern_return_t
kmod_finalize_cpp(kmod_info_t *info)
{
    return kmod_call_funcs_in_section((struct mach_header *)info->address, "__destructor");
}

kern_return_t
kmod_default_start(__unused struct kmod_info *ki, __unused void *data)
{
    return KMOD_RETURN_SUCCESS;
}

kern_return_t
kmod_default_stop(__unused struct kmod_info *ki, __unused void *data)
{
    return KMOD_RETURN_SUCCESS;
}

static void
kmod_dump_to(vm_offset_t *addr, unsigned int cnt,
	void (*printf_func)(const char *fmt, ...))
{
    vm_offset_t * kscan_addr = 0;
    kmod_info_t * k;
    kmod_reference_t * r;
    unsigned int i;
    int found_kmod = 0;
    kmod_info_t * stop_kmod = 0;

    for (k = kmod; k; k = k->next) {
        if (pmap_find_phys(kernel_pmap, (addr64_t)((uintptr_t)k)) == 0) {
            (*printf_func)("         kmod scan stopped due to missing "
                "kmod page: %08x\n", stop_kmod);
            break;
        }
        if (!k->address) {
            continue; // skip fake entries for built-in kernel components
        }
        for (i = 0, kscan_addr = addr; i < cnt; i++, kscan_addr++) {
            if ((*kscan_addr >= k->address) &&
                (*kscan_addr < (k->address + k->size))) {

                if (!found_kmod) {
                    (*printf_func)("      Kernel loadable modules in backtrace "
                        "(with dependencies):\n");
                }
                found_kmod = 1;
                (*printf_func)("         %s(%s)@0x%x\n",
                    k->name, k->version, k->address);

                for (r = k->reference_list; r; r = r->next) {
                    kmod_info_t * rinfo;

                    if (pmap_find_phys(kernel_pmap, (addr64_t)((uintptr_t)r)) == 0) {
                        (*printf_func)("            kmod dependency scan stopped "
                            "due to missing dependency page: %08x\n", r);
                        break;
                    }

                    rinfo = r->info;

                    if (pmap_find_phys(kernel_pmap, (addr64_t)((uintptr_t)rinfo)) == 0) {
                        (*printf_func)("            kmod dependency scan stopped "
                            "due to missing kmod page: %08x\n", rinfo);
                        break;
                    }

                    if (!rinfo->address) {
                        continue; // skip fake entries for built-ins
                    }

                    (*printf_func)("            dependency: %s(%s)@0x%x\n",
                        rinfo->name, rinfo->version, rinfo->address);
                }

                break;  // only report this kmod for one backtrace address
            }
        }
    }

    return;
}

void
kmod_dump(vm_offset_t *addr, unsigned int cnt)
{
    kmod_dump_to(addr, cnt, &kdb_printf);
}

void
kmod_dump_log(vm_offset_t *addr, unsigned int cnt)
{
    kmod_dump_to(addr, cnt, &printf);
}