/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * Copyright (c) 1990, 2010, Oracle and/or its affiliates. All rights reserved.
 */

#include <sys/param.h>
#include <sys/modctl.h>
#include <sys/modhash.h>
#include <sys/open.h>
#include <sys/conf.h>
#include <sys/errno.h>
#include <sys/sysmacros.h>
#include <sys/kmem.h>
#include <sys/cmn_err.h>
#include <sys/stat.h>
#include <sys/mode.h>
#include <sys/pathname.h>
#include <sys/vnode.h>
#include <sys/ddi_impldefs.h>
#include <sys/ddi_implfuncs.h>
#include <sys/esunddi.h>
#include <sys/sunddi.h>
#include <sys/sunndi.h>
#include <sys/systeminfo.h>
#include <sys/hwconf.h>
#include <sys/file.h>
#include <sys/varargs.h>
#include <sys/thread.h>
#include <sys/cred.h>
#include <sys/autoconf.h>
#include <sys/kobj.h>
#include <sys/consdev.h>
#include <sys/systm.h>
#include <sys/debug.h>
#include <sys/atomic.h>

extern struct dev_ops nodev_ops;
extern struct dev_ops mod_nodev_ops;

struct mod_noload {
        struct mod_noload *mn_next;
        char *mn_name;
};

/*
 * Function prototypes
 */
static int init_stubs(struct modctl *, struct mod_modinfo *);
static int nm_hash(const char *);
static void make_syscallname(const char *, int);
static void hwc_hash_init();
static void hwc_hash(struct hwc_spec *, major_t);
static void hwc_unhash(struct hwc_spec *);

int
major_valid(major_t major)
{
        return (major != DDI_MAJOR_T_NONE && major < devcnt);
}

int
driver_installed(major_t major)
{
        return (major_valid(major) && devnamesp[major].dn_name != NULL);
}

int
driver_active(major_t major)
{
        return (driver_installed(major) && !(devnamesp[major].dn_flags &
            (DN_DRIVER_REMOVED|DN_DRIVER_INACTIVE)));
}

struct dev_ops *
mod_hold_dev_by_major(major_t major)
{
        struct dev_ops **devopspp, *ops;
        int loaded;
        char *drvname;

        if (!driver_active(major))
                return (NULL);

        LOCK_DEV_OPS(&(devnamesp[major].dn_lock));
        devopspp = &devopsp[major];
        loaded = 1;
        while (loaded && !CB_DRV_INSTALLED(*devopspp)) {
                UNLOCK_DEV_OPS(&(devnamesp[major].dn_lock));
                drvname = mod_major_to_name(major);
                if (drvname == NULL)
                        return (NULL);
                loaded = (modload("drv", drvname) != -1);
                LOCK_DEV_OPS(&(devnamesp[major].dn_lock));
        }
        if (loaded) {
                INCR_DEV_OPS_REF(*devopspp);
                ops = *devopspp;
        } else {
                ops = NULL;
        }
        UNLOCK_DEV_OPS(&(devnamesp[major].dn_lock));
        return (ops);
}

#ifdef  DEBUG_RELE
static int mod_rele_pause = DEBUG_RELE;
#endif  /* DEBUG_RELE */

void
mod_rele_dev_by_major(major_t major)
{
        struct dev_ops *ops;
        struct devnames *dnp;

        if (!driver_active(major))
                return;

        dnp = &devnamesp[major];
        LOCK_DEV_OPS(&dnp->dn_lock);
        ops = devopsp[major];
        ASSERT(CB_DRV_INSTALLED(ops));

#ifdef  DEBUG_RELE
        if (!DEV_OPS_HELD(ops))  {
                char *s;
                static char *msg = "mod_rele_dev_by_major: unheld driver!";

                printf("mod_rele_dev_by_major: Major dev <%u>, name <%s>\n",
                    (uint_t)major,
                    (s = mod_major_to_name(major)) ? s : "unknown");
                if (mod_rele_pause)
                        debug_enter(msg);
                else
                        printf("%s\n", msg);
                UNLOCK_DEV_OPS(&dnp->dn_lock);
                return;                 /* XXX: Note changed behavior */
        }

#endif  /* DEBUG_RELE */

        if (!DEV_OPS_HELD(ops)) {
                cmn_err(CE_PANIC,
                    "mod_rele_dev_by_major: Unheld driver: major number <%u>",
                    (uint_t)major);
        }
        DECR_DEV_OPS_REF(ops);
        UNLOCK_DEV_OPS(&dnp->dn_lock);
}

struct dev_ops *
mod_hold_dev_by_devi(dev_info_t *devi)
{
        major_t major;
        char *name;

        name = ddi_get_name(devi);
        if ((major = mod_name_to_major(name)) == DDI_MAJOR_T_NONE)
                return (NULL);
        return (mod_hold_dev_by_major(major));
}

void
mod_rele_dev_by_devi(dev_info_t *devi)
{
        major_t major;
        char *name;

        name = ddi_get_name(devi);
        if ((major = mod_name_to_major(name)) == DDI_MAJOR_T_NONE)
                return;
        mod_rele_dev_by_major(major);
}

int
nomod_zero()
{
        return (0);
}

int
nomod_minus_one()
{
        return (-1);
}

int
nomod_einval()
{
        return (EINVAL);
}

void
nomod_void()
{
        /* nothing */
}

/*
 * Install all the stubs for a module.
 * Return zero if there were no errors or an errno value.
 */
int
install_stubs_by_name(struct modctl *modp, const char *name)
{
        char *p;
        const char *filenamep, *iter;
        char namebuf[MODMAXNAMELEN + 12];
        struct mod_modinfo *mp;

        iter = name;
        filenamep = name;

        while (*iter) {
                if (*iter++ == '/')
                        filenamep = iter;
        }

        /*
         * Concatenate "name" with "_modname" then look up this symbol
         * in the kernel.  If not found, we're done.
         * If found, then find the "mod" info structure and call init_stubs().
         */
        p = namebuf;

        while (*filenamep && *filenamep != '.')
                *p++ = *filenamep++;

        (void) strcpy(p, "_modinfo");

        if ((mp = (struct mod_modinfo *)modgetsymvalue(namebuf, 1)) != 0)
                return (init_stubs(modp, mp));
        else
                return (0);
}

static int
init_stubs(struct modctl *modp, struct mod_modinfo *mp)
{
        struct mod_stub_info *sp;
        int i;
        ulong_t offset;
        uintptr_t funcadr;
        char *funcname;

        modp->mod_modinfo = mp;

        /*
         * Fill in all stubs for this module.  We can't be lazy, since
         * some calls could come in from interrupt level, and we
         * can't modlookup then (symbols may be paged out).
         */
        sp = mp->modm_stubs;
        for (i = 0; sp->mods_func_adr; i++, sp++) {
                funcname = modgetsymname(sp->mods_stub_adr, &offset);
                if (funcname == NULL) {
                        printf("init_stubs: couldn't find symbol "
                            "in module %s\n", mp->modm_module_name);
                        return (EFAULT);
                }
                funcadr = kobj_lookup(modp->mod_mp, funcname);

                if (kobj_addrcheck(modp->mod_mp, (caddr_t)funcadr)) {
                        printf("%s:%s() not defined properly\n",
                            mp->modm_module_name, funcname);
                        return (EFAULT);
                }
                sp->mods_func_adr = funcadr;
        }
        mp->mp = modp;
        return (0);
}

/*
 * modp->mod_modinfo has to be checked in these functions before
 * mod_stub_info is accessed because it's not guranteed that all
 * modules define mod_stub_info structures.
 */
void
install_stubs(struct modctl *modp)
{
        struct mod_stub_info *stub;

        if (modp->mod_modinfo) {
                membar_producer();
                for (stub = modp->mod_modinfo->modm_stubs;
                    stub->mods_func_adr; stub++) {
                        stub->mods_flag |= MODS_INSTALLED;
                }
                membar_producer();
        }
}

void
uninstall_stubs(struct modctl *modp)
{
        struct mod_stub_info *stub;

        if (modp->mod_modinfo) {
                membar_producer();
                for (stub = modp->mod_modinfo->modm_stubs;
                    stub->mods_func_adr; stub++) {
                        stub->mods_flag &= ~MODS_INSTALLED;
                }
                membar_producer();
        }
}

void
reset_stubs(struct modctl *modp)
{
        struct mod_stub_info *stub;

        if (modp->mod_modinfo) {
                for (stub = modp->mod_modinfo->modm_stubs;
                    stub->mods_func_adr; stub++) {
                        if (stub->mods_flag & (MODS_WEAK | MODS_NOUNLOAD))
                                stub->mods_func_adr =
                                    (uintptr_t)stub->mods_errfcn;
                        else
                                stub->mods_func_adr =
                                    (uintptr_t)mod_hold_stub;
                }
                modp->mod_modinfo->mp = NULL;
        }
}

struct modctl *
mod_getctl(struct modlinkage *modlp)
{
        struct modctl   *modp;

        mutex_enter(&mod_lock);
        modp = &modules;
        do {
                if (modp->mod_linkage == modlp) {
                        mutex_exit(&mod_lock);
                        return (modp);
                }
        } while ((modp = modp->mod_next) != &modules);
        mutex_exit(&mod_lock);
        return (NULL);
}


/*
 * Attach driver.conf info to devnames for a driver
 */
struct par_list *
impl_make_parlist(major_t major)
{
        int err;
        struct par_list *pl = NULL, *tmp;
        ddi_prop_t *props = NULL;
        char *confname, *drvname;
        struct devnames *dnp;

        dnp = &devnamesp[major];

        ASSERT(mutex_owned(&dnp->dn_lock));

        /*
         * If .conf file already parsed or driver removed, just return.
         * May return NULL.
         */
        if (dnp->dn_flags & (DN_CONF_PARSED | DN_DRIVER_REMOVED))
                return (dnp->dn_pl);

        drvname = mod_major_to_name(major);
        if (drvname == NULL)
                return (NULL);

        confname = kmem_alloc(MAXNAMELEN, KM_SLEEP);
        (void) snprintf(confname, MAXNAMELEN, "drv/%s.conf", drvname);
        err = hwc_parse(confname, &pl, &props);
        kmem_free(confname, MAXNAMELEN);
        if (err)        /* file doesn't exist */
                return (NULL);

        /*
         * If there are global properties, reference it from dnp.
         */
        if (props)
                dnp->dn_global_prop_ptr = i_ddi_prop_list_create(props);

        /*
         * Hash specs to be looked up by nexus drivers
         */
        tmp = pl;
        while (tmp) {
                (void) hwc_hash(tmp->par_specs, major);
                tmp = tmp->par_next;
        }

        if (!i_ddi_io_initialized()) {
                if (i_ddi_prop_search(DDI_DEV_T_ANY, DDI_FORCEATTACH,
                    DDI_PROP_TYPE_INT, &props))
                        dnp->dn_flags |= DN_FORCE_ATTACH;
                if (i_ddi_prop_search(DDI_DEV_T_ANY, DDI_OPEN_RETURNS_EINTR,
                    DDI_PROP_TYPE_INT, &props))
                        dnp->dn_flags |= DN_OPEN_RETURNS_EINTR;
                if (i_ddi_prop_search(DDI_DEV_T_ANY, "scsi-size-clean",
                    DDI_PROP_TYPE_INT, &props))
                        dnp->dn_flags |= DN_SCSI_SIZE_CLEAN;
        }

        if (i_ddi_prop_search(DDI_DEV_T_ANY, DDI_VHCI_CLASS,
            DDI_PROP_TYPE_STRING, &props))
                dnp->dn_flags |= DN_PHCI_DRIVER;

        if (i_ddi_prop_search(DDI_DEV_T_ANY, DDI_DEVID_REGISTRANT,
            DDI_PROP_TYPE_INT, &props)) {
                dnp->dn_flags |= DN_DEVID_REGISTRANT;
        }

        dnp->dn_flags |= DN_CONF_PARSED;
        dnp->dn_pl = pl;
        return (pl);
}

/*
 * Destroy driver.conf info in devnames array for a driver
 */
int
impl_free_parlist(major_t major)
{
        struct par_list *pl;
        struct devnames *dnp = &devnamesp[major];

        /*
         * Unref driver global property list. Don't destroy it
         * because some instances may still be referencing it.
         * The property list will be freed when the last ref
         * goes away.
         */
        if (dnp->dn_global_prop_ptr) {
                i_ddi_prop_list_rele(dnp->dn_global_prop_ptr, dnp);
                dnp->dn_global_prop_ptr = NULL;
        }

        /*
         * remove specs from hash table
         */
        for (pl = dnp->dn_pl; pl; pl = pl->par_next)
                hwc_unhash(pl->par_specs);

        impl_delete_par_list(dnp->dn_pl);
        dnp->dn_pl = NULL;
        dnp->dn_flags &= ~DN_CONF_PARSED;
        return (0);
}

struct bind *mb_hashtab[MOD_BIND_HASHSIZE];
struct bind *sb_hashtab[MOD_BIND_HASHSIZE];

static int
nm_hash(const char *name)
{
        char c;
        int hash = 0;

        for (c = *name++; c; c = *name++)
                hash ^= c;

        return (hash & MOD_BIND_HASHMASK);
}

void
clear_binding_hash(struct bind **bhash)
{
        int i;
        struct bind *bp, *bp1;

        for (i = 0; i < MOD_BIND_HASHSIZE; i++) {
                bp = bhash[i];
                while (bp != NULL) {
                        kmem_free(bp->b_name, strlen(bp->b_name) + 1);
                        if (bp->b_bind_name) {
                                kmem_free(bp->b_bind_name,
                                    strlen(bp->b_bind_name) + 1);
                        }
                        bp1 = bp;
                        bp = bp->b_next;
                        kmem_free(bp1, sizeof (struct bind));
                }
                bhash[i] = NULL;
        }
}

/* Find an mbind by name match (caller can ask for deleted match) */
static struct bind *
find_mbind(const char *name, struct bind **hashtab, int deleted)
{
        struct bind     *mb;

        for (mb = hashtab[nm_hash(name)]; mb; mb = mb->b_next) {
                if (deleted && (mb->b_num >= 0))
                        continue;                       /* skip active */
                if (!deleted && (mb->b_num < 0))
                        continue;                       /* skip deleted */

                /* return if name matches */
                if (strcmp(name, mb->b_name) == 0) {
                        break;
                }
        }
        return (mb);
}

/*
 * Create an entry for the given (name, major, bind_name) tuple in the
 * hash table supplied.  Reject the attempt to do so if 'name' is already
 * in the hash table.
 *
 * Does not provide synchronization, so use only during boot or with
 * externally provided locking.
 */
int
make_mbind(char *name, int num, char *bind_name, struct bind **hashtab)
{
        struct bind     *mb;
        struct bind     **pmb;

        ASSERT(hashtab != NULL);
        ASSERT(num >= 0);

        /* Fail if the key being added is already established */
        if (find_mbind(name, hashtab, 0) != NULL)
                return (-1);

        /* Allocate new mbind */
        mb = kmem_zalloc(sizeof (struct bind), KM_SLEEP);
        mb->b_name = i_ddi_strdup(name, KM_SLEEP);
        mb->b_num = num;
        if (bind_name != NULL)
                mb->b_bind_name = i_ddi_strdup(bind_name, KM_SLEEP);

        /* Insert at head of hash */
        pmb = &hashtab[nm_hash(name)];
        mb->b_next = *pmb;
        *pmb = mb;
        return (0);
}

/*
 * Delete a binding from a binding-hash. Since there is no locking we
 * delete an mbind by making its b_num negative. We also support find_mbind
 * of deleted entries, so we still need deleted items on the list.
 */
void
delete_mbind(const char *name, struct bind **hashtab)
{
        struct bind     *mb;

        for (mb = hashtab[nm_hash(name)]; mb; mb = mb->b_next) {
                if ((mb->b_num >= 0) && (strcmp(name, mb->b_name) == 0)) {
                        /* delete by making b_num negative */
                        if (moddebug & MODDEBUG_BINDING) {
                                cmn_err(CE_CONT, "mbind: %s %d deleted\n",
                                    name, mb->b_num);
                        }
                        mb->b_num = -mb->b_num;
                        break;
                }
        }
}

/*
 * Delete all items in an mbind associated with specified num.
 * An example would be rem_drv deleting all aliases associated with a
 * driver major number.
 */
void
purge_mbind(int num, struct bind **hashtab)
{
        int             i;
        struct bind     *mb;

        /* search all hash lists for items that associated with 'num' */
        for (i = 0; i < MOD_BIND_HASHSIZE; i++) {
                for (mb = hashtab[i]; mb; mb = mb->b_next) {
                        if (mb->b_num == num) {
                                if (moddebug & MODDEBUG_BINDING)
                                        cmn_err(CE_CONT,
                                            "mbind: %s %d purged\n",
                                            mb->b_name, num);
                                /* purge by changing the sign */
                                mb->b_num = -num;
                        }
                }
        }
}

major_t
mod_name_to_major(const char *name)
{
        struct bind     *mbind;
        major_t         maj;

        /* Search for non-deleted match. */
        if ((mbind = find_mbind(name, mb_hashtab, 0)) != NULL) {
                if (moddebug & MODDEBUG_BINDING) {
                        if (find_mbind(name, mb_hashtab, 1))
                                cmn_err(CE_CONT,
                                    "'%s' has deleted match too\n", name);
                }
                return ((major_t)mbind->b_num);
        }

        /*
         * Search for deleted match: We may find that we have dependencies
         * on drivers that have been deleted (but the old driver may still
         * be bound to a node). These callers should be converted to use
         * ddi_driver_major(i.e. devi_major).
         */
        if (moddebug & MODDEBUG_BINDING) {
                if ((mbind = find_mbind(name, mb_hashtab, 1)) != NULL) {
                        maj = (major_t)(-(mbind->b_num));
                        cmn_err(CE_CONT, "Reference to deleted alias '%s' %d\n",
                            name, maj);
                }
        }

        return (DDI_MAJOR_T_NONE);
}

char *
mod_major_to_name(major_t major)
{
        if (!driver_installed(major))
                return (NULL);
        return ((&devnamesp[major])->dn_name);
}

/*
 * Set up the devnames array.  Error check for duplicate entries.
 */
void
init_devnamesp(int size)
{
        int hshndx;
        struct bind *bp;
        static char dupwarn[] =
            "!Device entry \"%s %d\" conflicts with previous entry \"%s %d\" "
            "in /etc/name_to_major.";
        static char badmaj[] = "The major number %u is invalid.";

        ASSERT(size <= L_MAXMAJ32 && size > 0);

        /*
         * Allocate the devnames array.  All mutexes and cv's will be
         * automagically initialized.
         */
        devnamesp = kobj_zalloc(size * sizeof (struct devnames), KM_SLEEP);

        /*
         * Stick the contents of mb_hashtab into the devnames array.  Warn if
         * two hash entries correspond to the same major number, or if a
         * major number is out of range.
         */
        for (hshndx = 0; hshndx < MOD_BIND_HASHSIZE; hshndx++) {
                for (bp = mb_hashtab[hshndx]; bp; bp = bp->b_next) {
                        if (make_devname(bp->b_name,
                            (major_t)bp->b_num, 0) != 0) {
                                /*
                                 * If there is not an entry at b_num already,
                                 * then this must be a bad major number.
                                 */
                                char *nm = mod_major_to_name(bp->b_num);
                                if (nm == NULL) {
                                        cmn_err(CE_WARN, badmaj,
                                            (uint_t)bp->b_num);
                                } else {
                                        cmn_err(CE_WARN, dupwarn, bp->b_name,
                                            bp->b_num, nm, bp->b_num);
                                }
                        }
                }
        }

        /* Initialize hash table for hwc_spec's */
        hwc_hash_init();
}

int
make_devname(const char *name, major_t major, int dn_flags)
{
        struct devnames *dnp;
        char *copy;

        /*
         * Until on-disk support for major nums > 14 bits arrives, fail
         * any major numbers that are too big.
         */
        if (major > L_MAXMAJ32)
                return (EINVAL);

        dnp = &devnamesp[major];
        LOCK_DEV_OPS(&dnp->dn_lock);
        if (dnp->dn_name) {
                if (strcmp(dnp->dn_name, name) != 0) {
                        /* Another driver already here */
                        UNLOCK_DEV_OPS(&dnp->dn_lock);
                        return (EINVAL);
                }
                /* Adding back a removed driver */
                dnp->dn_flags &= ~DN_DRIVER_REMOVED;
                dnp->dn_flags |= dn_flags;
                UNLOCK_DEV_OPS(&dnp->dn_lock);
                return (0);
        }

        /*
         * Check if flag is taken by getudev()
         */
        if (dnp->dn_flags & DN_TAKEN_GETUDEV) {
                UNLOCK_DEV_OPS(&dnp->dn_lock);
                return (EINVAL);
        }

        copy = kmem_alloc(strlen(name) + 1, KM_SLEEP);
        (void) strcpy(copy, name);

        /* Make sure string is copied before setting dn_name */
        membar_producer();
        dnp->dn_name = copy;
        dnp->dn_flags = dn_flags;
        UNLOCK_DEV_OPS(&dnp->dn_lock);
        return (0);
}

/*
 * Set up the syscallnames array.
 */
void
init_syscallnames(int size)
{
        int hshndx;
        struct bind *bp;

        syscallnames = kobj_zalloc(size * sizeof (char *), KM_SLEEP);

        for (hshndx = 0; hshndx < MOD_BIND_HASHSIZE; hshndx++) {
                for (bp = sb_hashtab[hshndx]; bp; bp = bp->b_next) {
                        if (bp->b_num < 0 || bp->b_num >= size) {
                                cmn_err(CE_WARN,
                                    "!Couldn't add system call \"%s %d\". "
                                    "Value out of range (0..%d) in "
                                    "/etc/name_to_sysnum.",
                                    bp->b_name, bp->b_num, size - 1);
                                continue;
                        }
                        make_syscallname(bp->b_name, bp->b_num);
                }
        }
}

static void
make_syscallname(const char *name, int sysno)
{
        char **cp = &syscallnames[sysno];

        if (*cp != NULL) {
                cmn_err(CE_WARN, "!Couldn't add system call \"%s %d\". "
                    "It conflicts with \"%s %d\" in /etc/name_to_sysnum.",
                    name, sysno, *cp, sysno);
                return;
        }
        *cp = kmem_alloc(strlen(name) + 1, KM_SLEEP);
        (void) strcpy(*cp, name);
}

/*
 * Given a system call name, get its number.
 */
int
mod_getsysnum(const char *name)
{
        struct bind *mbind;

        if ((mbind = find_mbind(name, sb_hashtab, 0)) != NULL)
                return (mbind->b_num);

        return (-1);
}

/*
 * Given a system call number, get the system call name.
 */
char *
mod_getsysname(int sysnum)
{
        return (syscallnames[sysnum]);
}

/*
 * Find the name of the module containing the specified pc.
 * Returns the name on success, "<unknown>" on failure.
 * No mod_lock locking is required because things are never deleted from
 * the &modules list.
 */
char *
mod_containing_pc(caddr_t pc)
{
        struct modctl   *mcp = &modules;

        do {
                if (mcp->mod_mp != NULL &&
                    (size_t)pc - (size_t)mcp->mod_text < mcp->mod_text_size)
                        return (mcp->mod_modname);
        } while ((mcp = mcp->mod_next) != &modules);
        return ("<unknown>");
}

/*
 * Hash tables for hwc_spec
 *
 * The purpose of these hash tables are to allow the framework to discover
 * all possible .conf children for a given nexus. There are two hash tables.
 * One is hashed based on parent name, the on the class name. Each
 * driver.conf file translates to a list of hwc_spec's. Adding and
 * removing the entire list is an atomic operation, protected by
 * the hwc_hash_lock.
 *
 * What we get from all the hashing is the function hwc_get_child_spec().
 */
#define HWC_SPEC_HASHSIZE       (1 << 6)        /* 64 */

static mod_hash_t *hwc_par_hash;        /* hash by parent name */
static mod_hash_t *hwc_class_hash;      /* hash by class name */
static kmutex_t hwc_hash_lock;          /* lock protecting hwc hashes */

/*
 * Initialize hash tables for parent and class specs
 */
static void
hwc_hash_init()
{
        hwc_par_hash = mod_hash_create_strhash("hwc parent spec hash",
            HWC_SPEC_HASHSIZE, mod_hash_null_valdtor);
        hwc_class_hash = mod_hash_create_strhash("hwc class spec hash",
            HWC_SPEC_HASHSIZE, mod_hash_null_valdtor);
}

/*
 * Insert a spec into hash table. hwc_hash_lock must be held
 */
static void
hwc_hash_insert(struct hwc_spec *spec, const char *name, mod_hash_t *hash)
{
        mod_hash_key_t key;
        struct hwc_spec *entry = NULL;

        ASSERT(name != NULL);

        if (mod_hash_find(hash, (mod_hash_key_t)name,
            (mod_hash_val_t)&entry) != 0) {
                /* Name doesn't exist, insert a new key */
                key = kmem_alloc(strlen(name) + 1, KM_SLEEP);
                (void) strcpy((char *)key, name);
                if (mod_hash_insert(hash, key, (mod_hash_val_t)spec) != 0) {
                        kmem_free(key, strlen(name) + 1);
                        cmn_err(CE_WARN, "hwc hash state inconsistent");
                }
                return;
        }

        /*
         * Name is already present, append spec to the list.
         * This is the case when driver.conf specifies multiple
         * nodes under a single parent or class.
         */
        while (entry->hwc_hash_next)
                entry = entry->hwc_hash_next;
        entry->hwc_hash_next = spec;
}

/*
 * Remove a spec entry from spec hash table, the spec itself is
 * destroyed external to this function.
 */
static void
hwc_hash_remove(struct hwc_spec *spec, const char *name, mod_hash_t *hash)
{
        char *key;
        struct hwc_spec *entry;

        ASSERT(name != NULL);

        if (mod_hash_find(hash, (mod_hash_key_t)name,
            (mod_hash_val_t)&entry) != 0) {
                return; /* name not found in hash */
        }

        /*
         * If the head is the spec to be removed, either destroy the
         * entry or replace it with the remaining list.
         */
        if (entry == spec) {
                if (spec->hwc_hash_next == NULL) {
                        (void) mod_hash_destroy(hash, (mod_hash_key_t)name);
                        return;
                }
                key = kmem_alloc(strlen(name) + 1, KM_SLEEP);
                (void) strcpy(key, name);
                (void) mod_hash_replace(hash, (mod_hash_key_t)key,
                    (mod_hash_val_t)spec->hwc_hash_next);
                spec->hwc_hash_next = NULL;
                return;
        }

        /*
         * If the head is not the one, look for the spec in the
         * hwc_hash_next linkage.
         */
        while (entry->hwc_hash_next && (entry->hwc_hash_next != spec))
                entry = entry->hwc_hash_next;

        if (entry->hwc_hash_next) {
                entry->hwc_hash_next = spec->hwc_hash_next;
                spec->hwc_hash_next = NULL;
        }
}

/*
 * Hash a list of specs based on either parent name or class name
 */
static void
hwc_hash(struct hwc_spec *spec_list, major_t major)
{
        struct hwc_spec *spec = spec_list;

        mutex_enter(&hwc_hash_lock);
        while (spec) {
                /* Put driver major here so parent can find it */
                spec->hwc_major = major;

                if (spec->hwc_parent_name != NULL) {
                        hwc_hash_insert(spec, spec->hwc_parent_name,
                            hwc_par_hash);
                } else if (spec->hwc_class_name != NULL) {
                        hwc_hash_insert(spec, spec->hwc_class_name,
                            hwc_class_hash);
                } else {
                        cmn_err(CE_WARN,
                            "hwc_hash: No class or parent specified");
                }
                spec = spec->hwc_next;
        }
        mutex_exit(&hwc_hash_lock);
}

/*
 * Remove a list of specs from hash tables. Don't destroy the specs yet.
 */
static void
hwc_unhash(struct hwc_spec *spec_list)
{
        struct hwc_spec *spec = spec_list;

        mutex_enter(&hwc_hash_lock);
        while (spec) {
                if (spec->hwc_parent_name != NULL) {
                        hwc_hash_remove(spec, spec->hwc_parent_name,
                            hwc_par_hash);
                } else if (spec->hwc_class_name != NULL) {
                        hwc_hash_remove(spec, spec->hwc_class_name,
                            hwc_class_hash);
                } else {
                        cmn_err(CE_WARN,
                            "hwc_unhash: No class or parent specified");
                }
                spec = spec->hwc_next;
        }
        mutex_exit(&hwc_hash_lock);
}

/*
 * Make a copy of specs in a hash entry and add to the end of listp.
 * Called by nexus to locate a list of child specs.
 *
 * entry is a list of hwc_spec chained together with hwc_hash_next.
 * listp points to list chained together with hwc_next.
 */
static void
hwc_spec_add(struct hwc_spec **listp, struct hwc_spec *entry,
    major_t match_major)
{
        /* Find the tail of the list */
        while (*listp)
                listp = &(*listp)->hwc_next;

        while (entry) {
                struct hwc_spec *spec;

                if ((match_major != DDI_MAJOR_T_NONE) &&
                    (match_major != entry->hwc_major)) {
                        entry = entry->hwc_hash_next;
                        continue;
                }

                /*
                 * Allocate spec and copy the content of entry.
                 * No need to copy class/parent name since caller
                 * already knows the parent dip.
                 */
                spec = kmem_zalloc(sizeof (*spec), KM_SLEEP);
                spec->hwc_devi_name = i_ddi_strdup(
                    entry->hwc_devi_name, KM_SLEEP);
                spec->hwc_major = entry->hwc_major;
                spec->hwc_devi_sys_prop_ptr = i_ddi_prop_list_dup(
                    entry->hwc_devi_sys_prop_ptr, KM_SLEEP);

                *listp = spec;
                listp = &spec->hwc_next;
                entry = entry->hwc_hash_next;
        }
}

/*
 * Given a dip, find the list of child .conf specs from most specific
 * (parent pathname) to least specific (class name).
 *
 * This function allows top-down loading to be implemented without
 * changing the format of driver.conf file.
 */
struct hwc_spec *
hwc_get_child_spec(dev_info_t *dip, major_t match_major)
{
        extern char *i_ddi_parname(dev_info_t *, char *);
        extern int i_ddi_get_exported_classes(dev_info_t *, char ***);
        extern void i_ddi_free_exported_classes(char **, int);

        int i, nclass;
        char **classes;
        struct hwc_spec *list = NULL;
        mod_hash_val_t val;
        char *parname, *parname_buf;
        char *deviname, *deviname_buf;
        char *pathname, *pathname_buf;
        char *bindname;
        char *drvname;

        pathname_buf = kmem_alloc(3 * MAXPATHLEN, KM_SLEEP);
        deviname_buf = pathname_buf + MAXPATHLEN;
        parname_buf = pathname_buf + (2 * MAXPATHLEN);

        mutex_enter(&hwc_hash_lock);

        /*
         * Lookup based on full path.
         * In the case of root node, ddi_pathname would return
         * null string so just skip calling it.
         * As the pathname always begins with /, no simpler
         * name can duplicate it.
         */
        pathname = (dip == ddi_root_node()) ? "/" :
            ddi_pathname(dip, pathname_buf);
        ASSERT(pathname != NULL);
        ASSERT(*pathname == '/');

        if (mod_hash_find(hwc_par_hash, (mod_hash_key_t)pathname, &val) == 0) {
                hwc_spec_add(&list, (struct hwc_spec *)val, match_major);
        }

        /*
         * Lookup nodename@address.
         * Note deviname cannot match pathname.
         */
        deviname = ddi_deviname(dip, deviname_buf);
        if (*deviname != '\0') {
                /*
                 * Skip leading / returned by ddi_deviname.
                 */
                ASSERT(*deviname == '/');
                deviname++;
                if ((*deviname != '\0') && (mod_hash_find(hwc_par_hash,
                    (mod_hash_key_t)deviname, &val) == 0))
                        hwc_spec_add(&list,
                            (struct hwc_spec *)val, match_major);
        }

        /*
         * Lookup bindingname@address.
         * Take care not to perform duplicate lookups.
         */
        parname = i_ddi_parname(dip, parname_buf);
        if (*parname != '\0') {
                ASSERT(*parname != '/');
                if ((strcmp(parname, deviname) != 0) &&
                    (mod_hash_find(hwc_par_hash,
                    (mod_hash_key_t)parname, &val) == 0)) {
                        hwc_spec_add(&list,
                            (struct hwc_spec *)val, match_major);
                }
        }

        /*
         * Lookup driver binding name
         */
        bindname = ddi_binding_name(dip);
        ASSERT(*bindname != '/');
        if ((strcmp(bindname, parname) != 0) &&
            (strcmp(bindname, deviname) != 0) &&
            (mod_hash_find(hwc_par_hash, (mod_hash_key_t)bindname, &val) == 0))
                hwc_spec_add(&list, (struct hwc_spec *)val, match_major);

        /*
         * Lookup driver name
         */
        drvname = (char *)ddi_driver_name(dip);
        ASSERT(*drvname != '/');
        if ((strcmp(drvname, bindname) != 0) &&
            (strcmp(drvname, parname) != 0) &&
            (strcmp(drvname, deviname) != 0) &&
            (mod_hash_find(hwc_par_hash, (mod_hash_key_t)drvname, &val) == 0))
                hwc_spec_add(&list, (struct hwc_spec *)val, match_major);

        kmem_free(pathname_buf, 3 * MAXPATHLEN);

        /*
         * Lookup classes exported by this node and lookup the
         * class hash table for all .conf specs
         */
        nclass = i_ddi_get_exported_classes(dip, &classes);
        for (i = 0; i < nclass; i++) {
                if (mod_hash_find(hwc_class_hash, (mod_hash_key_t)classes[i],
                    &val) == 0)
                        hwc_spec_add(&list, (struct hwc_spec *)val,
                            match_major);
        }
        i_ddi_free_exported_classes(classes, nclass);

        mutex_exit(&hwc_hash_lock);
        return (list);
}