8322 nl: misleading-indentation

[unleashed/tickless.git] / usr / src / uts / common / os / dacf.c

/*
 * 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 2008 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

#pragma ident   "%Z%%M% %I%     %E% SMI"

/*
 * DACF: device autoconfiguration support
 *
 * DACF provides a fast, lightweight policy engine for the I/O subsystem.
 * This policy engine provides a mechanism for auto-configuring and
 * auto-unconfiguring devices.
 *
 * After a device is attach(9E)ed, additional configuration may be needed in
 * order to make the device available for use by the system.  For example,
 * STREAMS modules may need to be pushed atop the driver in order to create
 * a STREAMS stack.  If the device is to be removed from the system, these
 * configuration operations need to be undone, and the device prepared for
 * detach(9E).
 *
 * It is desirable to move the implementation of such policies outside of the
 * kernel proper, since such operations are typically infrequent.  To this end,
 * DACF manages kernel modules in (module_path)/dacf directories.  These adhere
 * to the api defined in sys/dacf.h, and register sets of configuration
 * operations.  The kernel loads these modules when the operations they
 * implement are needed, and can unload them at any time thereafter.
 * Implementing configuration operations in external modules can also increase
 * code reuse.
 *
 * DACF provides a policy database which associates
 *
 *   (device descr., kernel action) --> (configuration operation, parameters)
 *
 * - Device description is matching rule, for example:
 *      minor-nodetype="ddi_keyboard"
 * - Kernel action is a reference to a dacf kernel hook.
 *      currently supported are "post-attach" and "pre-detach"
 * - Configuration action is a reference to a module and a set of operations
 *      within the module, for example:  consconfig:kbd_config
 * - Parameters is a list of name="value" parameters to be passed to the
 *      configuration operation when invoked.
 *
 * The contents of the rules database are loaded from /etc/dacf.conf upon boot.
 *
 * DACF kernel hooks are comprised of a call into the rule-matching engine,
 * using parameters from the hook in order find a matching rule.  If one is
 * found, the framework can invoke the configuration operation immediately, or
 * defer doing so until later, by putting the rule on a 'reservation list.'
 */

#include <sys/param.h>
#include <sys/modctl.h>
#include <sys/sysmacros.h>
#include <sys/kmem.h>
#include <sys/cmn_err.h>
#include <sys/pathname.h>
#include <sys/ddi_impldefs.h>
#include <sys/sunddi.h>
#include <sys/autoconf.h>
#include <sys/modhash.h>
#include <sys/dacf.h>
#include <sys/dacf_impl.h>
#include <sys/systm.h>
#include <sys/varargs.h>
#include <sys/debug.h>
#include <sys/log.h>
#include <sys/fs/snode.h>

/*
 * Enumeration of the ops exported by the dacf framework.
 *
 * To add a new op to the framework, add it to this list, update dacf.h,
 * (don't miss DACF_NUM_OPIDS) and modify dacf_rule_matrix.
 *
 */
typedef struct dacf_opmap {
        const char *name;
        dacf_opid_t id;
} dacf_opmap_t;

static dacf_opmap_t dacf_ops[] = {
        { "post-attach",        DACF_OPID_POSTATTACH            },
        { "pre-detach",         DACF_OPID_PREDETACH             },
        { NULL,                 0                               },
};

/*
 * Enumeration of the options exported by the dacf framework (currently none).
 *
 * To add a new option, add it to this array.
 */
typedef struct dacf_opt {
        const char *optname;
        uint_t optmask;
} dacf_opt_t;

static dacf_opt_t dacf_options[] = {
#ifdef DEBUG
        { "testopt",            1               },
        { "testopt2",           2               },
#endif
        { NULL,                 0               },
};

static char kmod_name[] = "__kernel";

/*
 * Enumeration of the device specifiers exported by the dacf framework.
 *
 * To add a new devspec to the framework, add it to this list, update dacf.h,
 * (don't miss DACF_NUM_DEVSPECS), modify dacf_rule_matrix, and modify
 * dacf_match().
 */
typedef struct dacf_ds {
        const char *name;
        dacf_devspec_t id;
} dacf_ds_t;

static dacf_ds_t dacf_devspecs[] = {
        { "minor-nodetype",     DACF_DS_MIN_NT          },
        { "driver-minorname",   DACF_DS_DRV_MNAME       },
        { "device-path",        DACF_DS_DEV_PATH        },
        { NULL,                 NULL                    },
};

mod_hash_t *posta_mntype, *posta_mname, *posta_devname; /* post-attach */
mod_hash_t *pred_mntype, *pred_mname, *pred_devname;    /* pre-detach */

mod_hash_t *dacf_module_hash;
mod_hash_t *dacf_info_hash;

/*
 * This is the lookup table for the hash tables that dacf manages.  Given an
 * op id and devspec type, one can obtain the hash for that type of data.
 */
mod_hash_t **dacf_rule_matrix[DACF_NUM_OPIDS][DACF_NUM_DEVSPECS] = {
        { &posta_mntype,        &posta_mname,   &posta_devname  },
        { &pred_mntype,         &pred_mname,    &pred_devname   },
};

kmutex_t dacf_lock;
kmutex_t dacf_module_lock;

int dacfdebug = 0;

static dacf_rule_t *dacf_rule_ctor(char *, char *, char *, dacf_opid_t,
    uint_t, dacf_arg_t *);
static mod_hash_t *dacf_get_op_hash(dacf_opid_t, dacf_devspec_t);
static void dacf_rule_val_dtor(mod_hash_val_t);
static void dacf_destroy_opsets(dacf_module_t *module);
static void dacf_opset_copy(dacf_opset_t *dst, dacf_opset_t *src);
static void dprintf(const char *, ...) __KPRINTFLIKE(1);

/*PRINTFLIKE1*/
static void
dprintf(const char *format, ...)
{
        va_list alist;
        char dp_buf[256], *dpbp;
        if (dacfdebug & DACF_DBG_MSGS) {
                va_start(alist, format);
                /*
                 * sprintf up the string that is 'dacf debug: <the message>'
                 */
                (void) sprintf(dp_buf, "dacf debug: ");
                dpbp = &(dp_buf[strlen(dp_buf)]);
                (void) vsnprintf(dpbp, sizeof (dp_buf) - strlen(dp_buf),
                    format, alist);
                printf(dp_buf);
                va_end(alist);
        }
}

/*
 * dacf_init()
 *      initialize the dacf framework by creating the various hash tables.
 */
void
dacf_init()
{
        int i, j;
        char hbuf[40];

        mutex_enter(&dacf_lock);

        dprintf("dacf_init: creating hashmatrix\n");

#ifdef DEBUG
        /*
         * Sanity check that DACF_NUM_DEVSPECS and the devspecs are in sync
         */
        for (i = 0; dacf_devspecs[i].name != NULL; i++)
                continue;
        ASSERT(i == DACF_NUM_DEVSPECS);

        /*
         * Sanity check that DACF_NUM_OPIDS and the dacf_ops are in sync
         */
        for (i = 0; dacf_ops[i].name != NULL; i++)
                continue;
        ASSERT(i == DACF_NUM_OPIDS);
#endif

        for (i = 0; i < DACF_NUM_OPIDS; i++) {
                for (j = 0; j < DACF_NUM_DEVSPECS; j++) {
                        if (dacf_rule_matrix[i][j] == NULL) {
                                continue;
                        }
                        /*
                         * Set up a hash table with no key destructor.  The
                         * keys are carried in the rule_t, so the val_dtor
                         * will take care of the key as well.
                         */
                        (void) snprintf(hbuf, sizeof (hbuf),
                            "dacf hashmatrix [%d][%d]", i, j);
                        *(dacf_rule_matrix[i][j]) = mod_hash_create_extended(
                            hbuf,                       /* hash name */
                            DACF_RULE_HASHSIZE,         /* # hash elems */
                            mod_hash_null_keydtor,      /* key dtor */
                            dacf_rule_val_dtor,         /* value dtor */
                            mod_hash_bystr, NULL,       /* hash alg & data */
                            mod_hash_strkey_cmp,        /* key comparator */
                            KM_SLEEP);
                }
        }

        dprintf("dacf_init: creating module_hash\n");
        /*
         * dacf_module_hash stores the currently registered dacf modules
         * by name.
         */
        dacf_module_hash = mod_hash_create_strhash("dacf module hash",
            DACF_MODULE_HASHSIZE, mod_hash_null_valdtor);

        dprintf("dacf_init: creating info_hash\n");
        /*
         * dacf_info_hash stores pointers to data that modules can associate
         * on a per minornode basis.  The type of data stored is opaque to the
         * framework-- thus there is no destructor supplied.
         */
        dacf_info_hash = mod_hash_create_ptrhash("dacf info hash",
            DACF_INFO_HASHSIZE, mod_hash_null_valdtor,
            sizeof (struct ddi_minor_data));

        mutex_exit(&dacf_lock);

        /*
         * Register the '__kernel' module.
         *
         * These are operations that are provided by the kernel, not by a
         * module.  We just feed the framework a dacfsw structure; it will get
         * marked as 'loaded' by dacf_module_register(), and will always be
         * available.
         */
        (void) dacf_module_register(kmod_name, &kmod_dacfsw);

        (void) read_dacf_binding_file(NULL);

        dprintf("dacf_init: dacf is ready\n");
}

/*
 * dacf_clear_rules()
 *      clear the dacf rule database.  This is typically done in advance of
 *      rereading the dacf binding file.
 */
void
dacf_clear_rules()
{
        int i, j;
        ASSERT(MUTEX_HELD(&dacf_lock));

        for (i = 0; i < DACF_NUM_OPIDS; i++) {
                for (j = 0; j < DACF_NUM_DEVSPECS; j++) {
                        if ((dacf_rule_matrix[i][j] != NULL) &&
                            (*(dacf_rule_matrix[i][j]) != NULL)) {
                                mod_hash_clear(*(dacf_rule_matrix[i][j]));
                        }
                }
        }
}

/*
 * dacf_rule_insert()
 *      Create an entry in the dacf rule database.
 *      If 'module' is null, the kernel is the 'module'. (see dacf_rule_ctor()).
 */
int
dacf_rule_insert(dacf_devspec_t devspec_type, char *devspec_data,
    char *module, char *opset, dacf_opid_t opid, uint_t opts,
    dacf_arg_t *op_args)
{
        dacf_rule_t *rule;
        mod_hash_t *hash;

        ASSERT(devspec_type != DACF_DS_ERROR);
        ASSERT(devspec_data);
        ASSERT(opset);
        ASSERT(MUTEX_HELD(&dacf_lock));

        dprintf("dacf_rule_insert called: %s=\"%s\", %s:%s, %s\n",
            dacf_devspec_to_str(devspec_type), devspec_data,
            module ? module : "[kernel]", opset, dacf_opid_to_str(opid));

        /*
         * Fetch the hash table associated with this op-name and devspec-type.
         * Some ops may not support all devspec-types, since they may be
         * meaningless, so hash may be null.
         */
        hash = dacf_get_op_hash(opid, devspec_type);
        if (hash == NULL) {
                cmn_err(CE_WARN, "!dacf dev-spec '%s' does not support op '%s'",
                    dacf_devspec_to_str(devspec_type), dacf_opid_to_str(opid));
                return (-1);
        }

        /*
         * Allocate a rule  and fill it in, take a hold on it.
         */
        rule = dacf_rule_ctor(devspec_data, module, opset, opid, opts,
            op_args);
        dacf_rule_hold(rule);

        if (mod_hash_insert(hash, (mod_hash_key_t)rule->r_devspec_data,
            (mod_hash_val_t)rule) != 0) {
                /*
                 * We failed, so release hold.  This will cause the rule and
                 * associated data to get nuked.
                 */
                dacf_rule_rele(rule);

                cmn_err(CE_WARN, "!dacf rule %s='%s' %s:%s %s duplicates "
                    "another rule, ignored", dacf_devspec_to_str(devspec_type),
                    devspec_data, module, opset, dacf_opid_to_str(opid));
                return (-1);
        }
        return (0);
}

/*
 * dacf_rule_ctor()
 *      Allocate and fill out entries in a dacf_rule_t.
 */
static dacf_rule_t *
dacf_rule_ctor(char *device_spec, char *module, char *opset, dacf_opid_t opid,
    uint_t opts, dacf_arg_t *op_args)
{
        dacf_rule_t *rule;
        dacf_arg_t *p;

        rule = kmem_alloc(sizeof (dacf_rule_t), KM_SLEEP);

        /*
         * Fill in the entries
         */
        rule->r_devspec_data = kmem_alloc(strlen(device_spec) + 1, KM_SLEEP);
        (void) strcpy(rule->r_devspec_data, device_spec);

        /*
         * If module is 'null' we set it to __kernel, meaning that this op
         * is implemented by the kernel.
         */
        if (module == NULL) {
                module = kmod_name;
        }

        rule->r_module = kmem_alloc(strlen(module) + 1, KM_SLEEP);
        (void) strcpy(rule->r_module, module);

        rule->r_opset = kmem_alloc(strlen(opset) + 1, KM_SLEEP);
        (void) strcpy(rule->r_opset, opset);

        rule->r_refs = 0;       /* no refs yet */
        rule->r_opts = opts;
        rule->r_opid = opid;

        rule->r_args = NULL;
        p = op_args;
        while (p != NULL) {
                ASSERT(p->arg_name);
                ASSERT(p->arg_val);
                /*
                 * dacf_arg_insert() should always succeed, since we're copying
                 * another (already duplicate-free) list.
                 */
                (void) dacf_arg_insert(&rule->r_args, p->arg_name, p->arg_val);
                p = p->arg_next;
        }

        return (rule);
}

/*
 * dacf_rule_val_dtor()
 *      This is the destructor for dacf_rule_t's in the rule database.  It
 *      simply does a dacf_rule_rele() on the rule.  This function will take
 *      care of destroying the rule if its ref count has dropped to 0.
 */
static void
dacf_rule_val_dtor(mod_hash_val_t val)
{
        ASSERT((void *)val != NULL);
        dacf_rule_rele((dacf_rule_t *)val);
}

/*
 * dacf_rule_destroy()
 *      destroy a dacf_rule_t
 */
void
dacf_rule_destroy(dacf_rule_t *rule)
{
        ASSERT(rule->r_refs == 0);
        /*
         * Free arguments.
         */
        dacf_arglist_delete(&(rule->r_args));
        kmem_free(rule->r_devspec_data, strlen(rule->r_devspec_data) + 1);
        /*
         * Module may be null for a kernel-managed op-set
         */
        kmem_free(rule->r_module, strlen(rule->r_module) + 1);
        kmem_free(rule->r_opset, strlen(rule->r_opset) + 1);
        kmem_free(rule, sizeof (dacf_rule_t));
}

/*
 * dacf_rule_hold()
 *      dacf rules are ref-counted.  This function increases the reference
 *      count on an rule.
 */
void
dacf_rule_hold(dacf_rule_t *rule)
{
        ASSERT(MUTEX_HELD(&dacf_lock));

        rule->r_refs++;
}

/*
 * dacf_rule_rele()
 *      drop the ref count on an rule, and destroy the rule if its
 *      ref count drops to 0.
 */
void
dacf_rule_rele(dacf_rule_t *rule)
{
        ASSERT(MUTEX_HELD(&dacf_lock));
        ASSERT(rule->r_refs > 0);

        rule->r_refs--;
        if (rule->r_refs == 0) {
                dacf_rule_destroy(rule);
        }
}

/*
 * dacf_rsrv_make()
 *      add an rule to a reservation list to be processed later.
 */
void
dacf_rsrv_make(dacf_rsrvlist_t *rsrv, dacf_rule_t *rule, void *info,
    dacf_rsrvlist_t **list)
{
        dacf_infohdl_t ihdl = info;
        ASSERT(MUTEX_HELD(&dacf_lock));
        ASSERT(info && rule && list);

        /*
         * Bump the ref count on rule, so it won't get freed as long as it's on
         * this reservation list.
         */
        dacf_rule_hold(rule);

        rsrv->rsrv_rule = rule;
        rsrv->rsrv_ihdl = ihdl;
        rsrv->rsrv_result = DDI_SUCCESS;
        rsrv->rsrv_next = *list;
        *list = rsrv;

        dprintf("dacf: reservation made\n");
}

/*
 * dacf_clr_rsrvs()
 *      clear reservation list of operations of type 'op'
 */
void
dacf_clr_rsrvs(dev_info_t *devi, dacf_opid_t op)
{
        dacf_process_rsrvs(&(DEVI(devi)->devi_dacf_tasks), op, DACF_PROC_RELE);
}

/*
 * dacf_process_rsrvs()
 *      iterate across a locked reservation list, processing each element
 *      which matches 'op' according to 'flags'.
 *
 *      if DACF_PROC_INVOKE is specified, the elements that match 'op'
 *      will have their operations invoked.  The return value from that
 *      operation is placed in the rsrv_result field of the dacf_rsrvlist_t
 */
void
dacf_process_rsrvs(dacf_rsrvlist_t **list, dacf_opid_t op, int flags)
{
        dacf_rsrvlist_t *p, *dp;
        dacf_rsrvlist_t **prevptr;

        ASSERT(MUTEX_HELD(&dacf_lock));
        ASSERT(list);
        ASSERT(flags != 0);

        if (*list == NULL)
                return;

        dprintf("dacf_process_rsrvs: opid = %d, flags = 0x%x\n", op, flags);

        /*
         * Walk the list, finding rules whose opid's match op, and performing
         * the work described by 'flags'.
         */
        prevptr = list;
        for (p = *list; p != NULL; ) {

                if (p->rsrv_rule->r_opid != op) {
                        prevptr = &(p->rsrv_next);
                        p = p->rsrv_next;
                        continue;
                }

                if (flags & DACF_PROC_INVOKE) {
                        p->rsrv_result = dacf_op_invoke(p->rsrv_rule,
                            p->rsrv_ihdl, 0);
                }

                if (flags & DACF_PROC_RELE) {
                        *prevptr = p->rsrv_next;
                        dp = p;
                        p = p->rsrv_next;
                        dacf_rule_rele(dp->rsrv_rule);
                        kmem_free(dp, sizeof (dacf_rsrvlist_t));
                } else {
                        prevptr = &(p->rsrv_next);
                        p = p->rsrv_next;
                }
        }
}

/*
 * dacf_get_op_hash()
 *      Given an op name, (i.e. "post-attach" or "pre-detach") and a
 *      devspec-type, return the hash that represents that op indexed
 *      by that devspec.
 */
static mod_hash_t *
dacf_get_op_hash(dacf_opid_t op, dacf_devspec_t ds_type)
{
        ASSERT(op <= DACF_NUM_OPIDS && op > 0);
        ASSERT(ds_type <= DACF_NUM_DEVSPECS && ds_type > 0);

        /*
         * dacf_rule_matrix is an array of pointers to pointers to hashes.
         */
        if (dacf_rule_matrix[op - 1][ds_type - 1] == NULL) {
                return (NULL);
        }
        return (*(dacf_rule_matrix[op - 1][ds_type - 1]));
}

/*
 * dacf_arg_insert()
 *      Create and insert an entry in an argument list.
 *      Returns -1 if the argument name is a duplicate of another already
 *      present in the hash.
 */
int
dacf_arg_insert(dacf_arg_t **list, char *name, char *val)
{
        dacf_arg_t *arg;

        /*
         * Don't allow duplicates.
         */
        for (arg = *list; arg != NULL; arg = arg->arg_next) {
                if (strcmp(arg->arg_name, name) == 0) {
                        return (-1);
                }
        }

        arg = kmem_alloc(sizeof (dacf_arg_t), KM_SLEEP);
        arg->arg_name = kmem_alloc(strlen(name) + 1, KM_SLEEP);
        (void) strcpy(arg->arg_name, name);
        arg->arg_val = kmem_alloc(strlen(val) + 1, KM_SLEEP);
        (void) strcpy(arg->arg_val, val);

        arg->arg_next = *list;
        *list = arg;

        return (0);
}

/*
 * dacf_arglist_delete()
 *      free all the elements of a list of dacf_arg_t's.
 */
void
dacf_arglist_delete(dacf_arg_t **list)
{
        dacf_arg_t *arg, *narg;
        arg = *list;
        while (arg != NULL) {
                narg = arg->arg_next;
                kmem_free(arg->arg_name, strlen(arg->arg_name) + 1);
                kmem_free(arg->arg_val, strlen(arg->arg_val) + 1);
                kmem_free(arg, sizeof (dacf_arg_t));
                arg = narg;
        }
        *list = NULL;
}

/*
 * dacf_match()
 *      Match a device-spec to a rule.
 */
dacf_rule_t *
dacf_match(dacf_opid_t op, dacf_devspec_t ds, void *match_info)
{
        dacf_rule_t *rule;

        ASSERT(MUTEX_HELD(&dacf_lock));

        if (mod_hash_find(dacf_get_op_hash(op, ds), (mod_hash_key_t)match_info,
            (mod_hash_val_t *)&rule) == 0) {
                return (rule);
        }

        return (NULL);  /* Not Found */
}

/*
 * dacf_module_register()
 *      register a module with the framework.  Use when a module gets loaded,
 *      or for the kernel to register a "virtual" module (i.e. a "module"
 *      which the kernel provides).  Makes a copy of the interface description
 *      provided by the module.
 */
int
dacf_module_register(char *mod_name, struct dacfsw *sw)
{
        char *str;
        size_t i, nelems;
        dacf_module_t *module;
        dacf_opset_t *opsarray;

        if (sw == NULL) {
                return (EINVAL);
        }

        if (sw->dacf_rev != DACF_MODREV_1) {
                cmn_err(CE_WARN, "dacf: module '%s' exports unsupported "
                    "version %d interface, not registered\n", mod_name,
                    sw->dacf_rev);
                return (EINVAL);
        }

        /*
         * count how many opsets are provided.
         */
        for (nelems = 0; sw->dacf_opsets[nelems].opset_name != NULL; nelems++)
                ;

        dprintf("dacf_module_register: found %lu opsets\n", nelems);

        /*
         * Temporary: It's ok for the kernel dacf_sw to have no opsets, since
         * we don't have any opsets to export yet (in NON-DEBUG).
         */
        if ((nelems == 0) && (sw != &kmod_dacfsw)) {
                cmn_err(CE_WARN, "dacf module %s exports no opsets, "
                    "not registered.\n", mod_name);
                return (EINVAL);
        }

        /*
         * Look to see if the module has been previously registered with the
         * framework.  If so, we can fail with EBUSY.
         */
        if (mod_hash_find(dacf_module_hash, (mod_hash_key_t)mod_name,
            (mod_hash_val_t)&module) == 0) {
                /*
                 * See if it is loaded currently
                 */
                rw_enter(&module->dm_lock, RW_WRITER);
                if (module->dm_loaded) {
                        rw_exit(&module->dm_lock);
                        cmn_err(CE_WARN, "dacf module '%s' is "
                            "already registered.", mod_name);
                        return (EBUSY);
                }
        } else {
                /*
                 * This is the first time we've ever seen the module; stick
                 * it into the module hash.  If that fails, we've had a
                 * race between two threads, both trying to insert the same
                 * new module.  It's safe to stick the module into the
                 * hash only partly filled in, since dm_lock protects the
                 * structure, and we've got that write-locked.
                 */
                module = kmem_zalloc(sizeof (dacf_module_t), KM_SLEEP);
                str = kmem_alloc(strlen(mod_name) + 1, KM_SLEEP);
                (void) strcpy(str, mod_name);
                rw_enter(&module->dm_lock, RW_WRITER);

                if (mod_hash_insert(dacf_module_hash, (mod_hash_key_t)str,
                    (mod_hash_val_t)module) != 0) {
                        rw_exit(&module->dm_lock);
                        kmem_free(str, strlen(str) + 1);
                        kmem_free(module, sizeof (dacf_module_t));
                        cmn_err(CE_WARN, "dacf module '%s' is "
                            "already registered.", mod_name);
                        return (EBUSY);
                }
        }
        /*
         * In either case (first time we've seen it or not), the module is
         * not loaded, and we hold it write-locked.
         */
        ASSERT(RW_WRITE_HELD(&module->dm_lock));

        /*
         * Alloc array of opsets for this module.  Add one for the final
         * NULL entry
         */
        opsarray = kmem_zalloc(sizeof (dacf_opset_t) * (nelems + 1), KM_SLEEP);

        for (i = 0; i < nelems; i++) {
                dacf_opset_copy(&(opsarray[i]), &(sw->dacf_opsets[i]));
                ASSERT(opsarray[i].opset_name != NULL);
                ASSERT(opsarray[i].opset_ops != NULL);
        }
        opsarray[nelems].opset_name = NULL;
        opsarray[nelems].opset_ops = NULL;

        ASSERT(module->dm_opsets == NULL);      /* see dacf_destroy_opsets() */
        module->dm_opsets = opsarray;

        if (dacfdebug & DACF_DBG_MSGS) {
                dprintf("%s registered.\n", mod_name);
                for (i = 0; i < nelems; i++) {
                        dprintf("registered %s\n", opsarray[i].opset_name);
                }
        }

        module->dm_loaded = 1;
        rw_exit(&module->dm_lock);

        return (0);
}

/*
 * dacf_module_unregister()
 *      remove a module from the framework, and free framework-allocated
 *      resources.
 */
int
dacf_module_unregister(char *mod_name)
{
        dacf_module_t *module;

        /*
         * Can't unregister __kernel, since there is no real way to get it
         * back-- Once it gets marked with dm_loaded == 0, the kernel will
         * try to modload() if it is ever needed, which will fail utterly,
         * and send op_invoke into a loop in it's modload logic
         *
         * If this is behavior is ever needed in the future, we can just
         * add a flag indicating that this module is really a fake.
         */
        ASSERT(strcmp(mod_name, kmod_name) != 0);

        dprintf("dacf_module_unregister: called for '%s'!\n", mod_name);

        /*
         * If NOAUL_DACF is set, or we try to get a write-lock on dm_lock and
         * that fails, return EBUSY, and fail to unregister.
         */
        if (mod_hash_find(dacf_module_hash, (mod_hash_key_t)mod_name,
            (mod_hash_val_t)&module) == 0) {
                if ((moddebug & MODDEBUG_NOAUL_DACF) ||
                    !rw_tryenter(&module->dm_lock, RW_WRITER)) {
                        return (EBUSY);
                }
        } else {
                return (EINVAL);
        }

        ASSERT(RW_WRITE_HELD(&module->dm_lock));
        dacf_destroy_opsets(module);
        module->dm_loaded = 0;
        rw_exit(&module->dm_lock);
        return (0);
}

/*
 * dacf_destroy_opsets()
 *      given a module, destroy all of it's associated op-sets.
 */
static void
dacf_destroy_opsets(dacf_module_t *module)
{
        dacf_opset_t *array = module->dm_opsets;
        dacf_opset_t *p;
        int i;
        size_t nelems;

        ASSERT(RW_WRITE_HELD(&module->dm_lock));
        ASSERT(module->dm_loaded == 1);

        for (i = 0; array[i].opset_name != NULL; i++) {
                p = &(array[i]);
                kmem_free(p->opset_name, strlen(p->opset_name) + 1);
                /*
                 * count nelems in opset_ops
                 */
                for (nelems = 0; ; nelems++) {
                        if (p->opset_ops[nelems].op_id == DACF_OPID_END) {
                                break;
                        }
                }
                /*
                 * Free the array of op ptrs.
                 */
                kmem_free(p->opset_ops, sizeof (dacf_op_t) * (nelems + 1));
        }

        /*
         * i has counted how big array is; +1 to account for the last element.
         */
        kmem_free(array, (sizeof (dacf_opset_t)) * (i + 1));
        module->dm_opsets = NULL;
}

/*
 * dacf_opset_copy()
 *      makes a copy of a dacf_opset_t.
 */
static void
dacf_opset_copy(dacf_opset_t *dst, dacf_opset_t *src)
{
        size_t nelems, i;
        ASSERT(src && dst);

        dprintf("dacf_opset_copy: called\n");

        dst->opset_name = kmem_alloc(strlen(src->opset_name) + 1, KM_SLEEP);
        (void) strcpy(dst->opset_name, src->opset_name);

        dprintf("dacf_opset_copy: counting ops\n");

        for (nelems = 0; ; nelems++) {
                if ((src->opset_ops[nelems].op_id == DACF_OPID_END) ||
                    (src->opset_ops[nelems].op_func == NULL)) {
                        break;
                }
        }

        dprintf("dacf_opset_copy: found %lu ops\n", nelems);

        dst->opset_ops = kmem_alloc(sizeof (dacf_op_t) * (nelems + 1),
            KM_SLEEP);

        dprintf("dacf_opset_copy: copying ops\n");
        for (i = 0; i < nelems; i++) {
                dst->opset_ops[i].op_id = src->opset_ops[i].op_id;
                dst->opset_ops[i].op_func = src->opset_ops[i].op_func;
        }
        dst->opset_ops[nelems].op_id = DACF_OPID_END;
        dst->opset_ops[nelems].op_func = NULL;

        dprintf("dacf_opset_copy: done copying ops\n");
}

int dacf_modload_laps = 0;      /* just a diagnostic aid */

/*
 * dacf_op_invoke()
 *      Invoke a op in a opset in a module given the rule to invoke.
 *
 *      If the return value of dacf_op_invoke is 0, then rval contains the
 *      return value of the _op_ being invoked. Otherwise, dacf_op_invoke's
 *      return value indicates why the op invocation failed.
 */
int
dacf_op_invoke(dacf_rule_t *rule, dacf_infohdl_t info_hdl, int flags)
{
        dacf_module_t *module;
        dacf_opset_t *opsarray;
        dacf_opset_t *opset;
        dacf_op_t *op = NULL;
        dacf_opid_t op_id;
        dacf_arghdl_t arg_hdl;
        dev_info_t *dip;
        int i, rval = -1;

        ASSERT(rule);
        ASSERT(MUTEX_HELD(&dacf_lock));

        op_id = rule->r_opid;
        dprintf("dacf_op_invoke: opid=%d\n", op_id);

        /*
         * Take laps, trying to load the dacf module.  For the case of kernel-
         * provided operations, __kernel will be found in the hash table, and
         * no modload will be needed.
         */
        for (;;) {
                if (mod_hash_find(dacf_module_hash,
                    (mod_hash_key_t)rule->r_module,
                    (mod_hash_val_t *)&module) == 0) {
                        rw_enter(&module->dm_lock, RW_READER);
                        /*
                         * Found the module, and it is loaded.
                         */
                        if (module->dm_loaded != 0) {
                                break;
                        }
                        rw_exit(&module->dm_lock);
                }

                /*
                 * If we're here, either: 1) it's not in the hash, or 2) it is,
                 * but dm_loaded is 0, meaning the module needs to be loaded.
                 */
                dprintf("dacf_op_invoke: calling modload\n");
                if (modload("dacf", rule->r_module) < 0) {
                        return (DACF_ERR_MOD_NOTFOUND);
                }
                dacf_modload_laps++;
        }

        ASSERT(RW_READ_HELD(&module->dm_lock));

        opsarray = module->dm_opsets;

        /*
         * Loop through the opsets exported by this module, and find the one
         * we care about.
         */
        opset = NULL;
        for (i = 0; opsarray[i].opset_name != NULL; i++) {
                if (strcmp(opsarray[i].opset_name, rule->r_opset) == 0) {
                        opset = &opsarray[i];
                        break;
                }
        }

        if (opset == NULL) {
                cmn_err(CE_WARN, "!dacf: couldn't invoke op, opset '%s' not "
                    "found in module '%s'", rule->r_opset, rule->r_module);
                rw_exit(&module->dm_lock);
                return (DACF_ERR_OPSET_NOTFOUND);
        }

        arg_hdl = (dacf_arghdl_t)rule->r_args;

        /*
         * Call the appropriate routine in the target by looping across the
         * ops until we find the one whose id matches opid.
         */
        op = NULL;
        for (i = 0; opset->opset_ops[i].op_id != DACF_OPID_END; i++) {
                if (opset->opset_ops[i].op_id == op_id) {
                        op = &(opset->opset_ops[i]);
                        break;
                }
        }

        if (op == NULL) {
                cmn_err(CE_WARN, "!dacf: couldn't invoke op, op '%s' not found "
                    "in opset '%s' in module '%s'", dacf_opid_to_str(op_id),
                    rule->r_opset, rule->r_module);
                rw_exit(&module->dm_lock);
                return (DACF_ERR_OP_NOTFOUND);
        }

        dprintf("dacf_op_invoke: found op, invoking...\n");

        /*
         * Drop dacf_lock here, so that op_func's that cause drivers to
         * get loaded don't wedge the system when they try to acquire dacf_lock
         * to do matching.
         *
         * Mark that an invoke is happening to prevent recursive invokes
         */
        dip = ((struct ddi_minor_data *)info_hdl)->dip;

        mutex_enter(&(DEVI(dip)->devi_lock));
        DEVI_SET_INVOKING_DACF(dip);
        mutex_exit(&(DEVI(dip)->devi_lock));

        mutex_exit(&dacf_lock);

        rval = op->op_func(info_hdl, arg_hdl, flags);

        mutex_enter(&dacf_lock);

        /*
         * Completed the invocation against module, so let go of it.
         */
        mutex_enter(&(DEVI(dip)->devi_lock));
        DEVI_CLR_INVOKING_DACF(dip);
        mutex_exit(&(DEVI(dip)->devi_lock));

        /*
         * Drop our r-lock on the module, now that we no longer need the module
         * to stay loaded.
         */
        rw_exit(&module->dm_lock);

        if (rval == DACF_SUCCESS) {
                return (DACF_SUCCESS);
        } else {
                return (DACF_ERR_OP_FAILED);
        }
}

/*
 * dacf_get_devspec()
 *      given a devspec-type as a string, return a corresponding dacf_devspec_t
 */
dacf_devspec_t
dacf_get_devspec(char *name)
{
        dacf_ds_t *p = &dacf_devspecs[0];

        while (p->name != NULL) {
                if (strcmp(p->name, name) == 0) {
                        return (p->id);
                }
                p++;
        }
        return (DACF_DS_ERROR);
}

/*
 * dacf_devspec_to_str()
 *      given a dacf_devspec_t, return a pointer to the human readable string
 *      representation of that device specifier.
 */
const char *
dacf_devspec_to_str(dacf_devspec_t ds)
{
        dacf_ds_t *p = &dacf_devspecs[0];

        while (p->name != NULL) {
                if (p->id == ds) {
                        return (p->name);
                }
                p++;
        }
        return (NULL);
}

/*
 * dacf_get_op()
 *      given a op name, returns the corresponding dacf_opid_t.
 */
dacf_opid_t
dacf_get_op(char *name)
{
        dacf_opmap_t *p = &dacf_ops[0];

        while (p->name != NULL) {
                if (strcmp(p->name, name) == 0) {
                        return (p->id);
                }
                p++;
        }
        return (DACF_OPID_ERROR);
}

/*
 * dacf_opid_to_str()
 *      given a dacf_opid_t, return the human-readable op-name.
 */
const char *
dacf_opid_to_str(dacf_opid_t tid)
{
        dacf_opmap_t *p = &dacf_ops[0];

        while (p->name != NULL) {
                if (p->id == tid) {
                        return (p->name);
                }
                p++;
        }
        return (NULL);
}

/*
 * dacf_getopt()
 *      given an option specified as a string, add it to the bit-field of
 *      options given.  Returns -1 if the option is unrecognized.
 */
int
dacf_getopt(char *opt_str, uint_t *opts)
{
        dacf_opt_t *p = &dacf_options[0];

        /*
         * Look through the list for the option given
         */
        while (p->optname != NULL) {
                if (strcmp(opt_str, p->optname) == 0) {
                        *opts |= p->optmask;
                        return (0);
                }
                p++;
        }
        return (-1);
}



/*
 * This family of functions forms the dacf interface which is exported to
 * kernel/dacf modules.  Modules _should_not_ use any dacf_* functions
 * presented above this point.
 *
 * Note: These routines use a dacf_infohdl_t to struct ddi_minor_data * and
 * assume that the resulting pointer is not to an alias node.  That is true
 * because dacf_op_invoke guarantees it by first resolving the alias.
 */

/*
 * dacf_minor_name()
 *      given a dacf_infohdl_t, obtain the minor name of the device instance
 *      being configured.
 */
const char *
dacf_minor_name(dacf_infohdl_t info_hdl)
{
        struct ddi_minor_data *dmdp = (struct ddi_minor_data *)info_hdl;

        return (dmdp->ddm_name);
}

/*
 * dacf_minor_number()
 *      given a dacf_infohdl_t, obtain the device minor number of the instance
 *      being configured.
 */
minor_t
dacf_minor_number(dacf_infohdl_t info_hdl)
{
        struct ddi_minor_data *dmdp = (struct ddi_minor_data *)info_hdl;

        return (getminor(dmdp->ddm_dev));
}

/*
 * dacf_get_dev()
 *      given a dacf_infohdl_t, obtain the dev_t of the instance being
 *      configured.
 */
dev_t
dacf_get_dev(dacf_infohdl_t info_hdl)
{
        struct ddi_minor_data *dmdp = (struct ddi_minor_data *)info_hdl;

        return (dmdp->ddm_dev);
}

/*
 * dacf_driver_name()
 *      given a dacf_infohdl_t, obtain the device driver name of the device
 *      instance being configured.
 */
const char *
dacf_driver_name(dacf_infohdl_t info_hdl)
{
        struct ddi_minor_data *dmdp = (struct ddi_minor_data *)info_hdl;

        return (ddi_driver_name(dmdp->dip));
}

/*
 * dacf_devinfo_node()
 *      given a dacf_infohdl_t, obtain the dev_info_t of the device instance
 *      being configured.
 */
dev_info_t *
dacf_devinfo_node(dacf_infohdl_t info_hdl)
{
        struct ddi_minor_data *dmdp = (struct ddi_minor_data *)info_hdl;

        return (dmdp->dip);
}

/*
 * dacf_get_arg()
 *      given the dacf_arghdl_t passed to a op and the name of an argument,
 *      return the value of that argument.
 *
 *      returns NULL if the argument is not found.
 */
const char *
dacf_get_arg(dacf_arghdl_t arghdl, char *arg_name)
{
        dacf_arg_t *arg_list = (dacf_arg_t *)arghdl;
        ASSERT(arg_name);

        while (arg_list != NULL) {
                if (strcmp(arg_list->arg_name, arg_name) == 0) {
                        return (arg_list->arg_val);
                }
                arg_list = arg_list->arg_next;
        }

        return (NULL);
}

/*
 * dacf_store_info()
 *      associate instance-specific data with a device instance.  Future
 *      configuration ops invoked for this instance can retrieve this data using
 *      dacf_retrieve_info() below.  Modules are responsible for cleaning up
 *      this data as appropriate, and should store NULL as the value of 'data'
 *      when the data is no longer valid.
 */
void
dacf_store_info(dacf_infohdl_t info_hdl, void *data)
{
        struct ddi_minor_data *dmdp = (struct ddi_minor_data *)info_hdl;

        /*
         * If the client is 'storing NULL' we can represent that by blowing
         * the info entry out of the hash.
         */
        if (data == NULL) {
                (void) mod_hash_destroy(dacf_info_hash, (mod_hash_key_t)dmdp);
        } else {
                /*
                 * mod_hash_replace can only fail on out of memory, but we sleep
                 * for memory in this hash, so it is safe to ignore the retval.
                 */
                (void) mod_hash_replace(dacf_info_hash, (mod_hash_key_t)dmdp,
                    (mod_hash_val_t)data);
        }
}

/*
 * dacf_retrieve_info()
 *      retrieve instance-specific data associated with a device instance.
 */
void *
dacf_retrieve_info(dacf_infohdl_t info_hdl)
{
        struct ddi_minor_data *dmdp = (struct ddi_minor_data *)info_hdl;
        void *data;

        if (mod_hash_find(dacf_info_hash, (mod_hash_key_t)dmdp,
            (mod_hash_val_t *)&data) != 0) {
                return (NULL);
        }

        return (data);
}

/*
 * dacf_makevp()
 *      make a vnode for the specified dacf_infohdl_t.
 */
struct vnode *
dacf_makevp(dacf_infohdl_t info_hdl)
{
        struct ddi_minor_data *dmdp = (struct ddi_minor_data *)info_hdl;
        struct vnode    *vp;

        vp = makespecvp(dmdp->ddm_dev, VCHR);
        spec_assoc_vp_with_devi(vp, dmdp->dip);
        return (vp);
}