/*
 * Copyright (C) 1999, 2000  Internet Software Consortium.
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM
 * DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL
 * INTERNET SOFTWARE CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT,
 * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING
 * FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT,
 * NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION
 * WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

/* $Id: master.c,v 1.74 2000/10/20 02:21:46 marka Exp $ */

#include <config.h>

#include <isc/event.h>
#include <isc/lex.h>
#include <isc/magic.h>
#include <isc/mem.h>
#include <isc/print.h>
#include <isc/stdtime.h>
#include <isc/string.h>
#include <isc/task.h>
#include <isc/util.h>

#include <dns/callbacks.h>
#include <dns/events.h>
#include <dns/fixedname.h>
#include <dns/master.h>
#include <dns/name.h>
#include <dns/rdata.h>
#include <dns/rdataclass.h>
#include <dns/rdatalist.h>
#include <dns/rdataset.h>
#include <dns/rdatatype.h>
#include <dns/result.h>
#include <dns/time.h>
#include <dns/ttl.h>

/*
 * Grow the number of dns_rdatalist_t (RDLSZ) and dns_rdata_t (RDSZ) structures
 * by these sizes when we need to.
 *
 * RDLSZ reflects the number of different types with the same name expected.
 * RDSZ reflects the number of rdata expected at a give name that can fit into
 * 64k.
 */

#define RDLSZ 32
#define RDSZ 512

#define NBUFS 4
#define MAXWIRESZ 255

/*
 * Target buffer size and minimum target size.
 * MINTSIZ must be big enough to hold the largest rdata record.
 *
 * TSIZ >= MINTSIZ
 */
#define TSIZ (128*1024)
/*
 * max message size - header - root - type - class - ttl - rdlen
 */
#define MINTSIZ (65535 - 12 - 1 - 2 - 2 - 4 - 2)
/*
 * Size for tokens in the presentation format,
 * The largest tokens are the base64 blocks in KEY and CERT records,
 * Largest key allowed is about 1372 bytes but
 * there is no fixed upper bound on CERT records.
 * 2K is too small for some X.509s, 8K is overkill.
 */
#define TOKENSIZ (8*1024)

#define DNS_MASTER_BUFSZ 2048

typedef ISC_LIST(dns_rdatalist_t) rdatalist_head_t;

/*
 * Master file loading state that persists across $INCLUDEs.
 */

struct dns_loadctx {
	isc_uint32_t		magic;
	isc_mem_t		*mctx;
	isc_lex_t		*lex;
	dns_loadctx_t		*parent;
	dns_rdatacallbacks_t	*callbacks;
	isc_task_t		*task;
	dns_loaddonefunc_t	done;
	void			*done_arg;
	isc_boolean_t		ttl_known;
	isc_boolean_t		default_ttl_known;
	isc_boolean_t		warn_1035;
	isc_boolean_t		age_ttl;
	isc_boolean_t		seen_include;
	isc_uint32_t		ttl;
	isc_uint32_t		default_ttl;
	dns_rdataclass_t	zclass;
	dns_fixedname_t		fixed_top;
	dns_fixedname_t		fixed[NBUFS];		/* working buffers */
	unsigned int		in_use[NBUFS];		/* covert to bitmap? */
	dns_name_t		*top;			/* top of zone */
	dns_name_t		*origin;
	dns_name_t		*current;
	dns_name_t		*glue;
	/* Which fixed buffers we are using? */
	int			glue_in_use;
	int			current_in_use;
	int			origin_in_use;
	unsigned int		loop_cnt;		/* records per quantum,
							 * 0 => all. */
	isc_boolean_t		canceled;
	/* Rate limit goo. */
	isc_boolean_t		rate_limited;
	ISC_LINK(dns_loadctx_t)	link;
	char			*master_file;
	dns_loadmgr_t		*loadmgr;
	isc_event_t		event;

	isc_mutex_t		lock;
	/* locked by lock */
	isc_uint32_t		references;
};

#define DNS_LCTX_MAGIC ISC_MAGIC('L','c','t','x')
#define DNS_LCTX_VALID(ctx) ISC_MAGIC_VALID(ctx, DNS_LCTX_MAGIC)

struct dns_loadmgr {
	isc_uint32_t		magic;
	isc_mem_t		*mctx;
	isc_uint32_t		erefs;
	isc_uint32_t		irefs;
	isc_mutex_t		lock;
	isc_uint32_t		active;
	isc_uint32_t		limit;
	ISC_LIST(dns_loadctx_t)	list;
};

#define DNS_LMGR_MAGIC ISC_MAGIC('L','m','g','r')
#define DNS_LMGR_VALID(ctx) ISC_MAGIC_VALID(ctx, DNS_LMGR_MAGIC)

static isc_result_t
pushfile(const char *master_file, dns_name_t *origin, dns_loadctx_t **ctxp);

static isc_result_t
commit(dns_rdatacallbacks_t *, isc_lex_t *, rdatalist_head_t *, dns_name_t *,
       dns_name_t *);

static isc_boolean_t
is_glue(rdatalist_head_t *, dns_name_t *);

static dns_rdatalist_t *
grow_rdatalist(int, dns_rdatalist_t *, int, rdatalist_head_t *,
		rdatalist_head_t *, isc_mem_t *mctx);

static dns_rdata_t *
grow_rdata(int, dns_rdata_t *, int, rdatalist_head_t *, rdatalist_head_t *,
	   isc_mem_t *);

static void
load_quantum(isc_task_t *task, isc_event_t *event);

static isc_result_t
task_send(dns_loadctx_t *ctx);

static void
loadctx_destroy(dns_loadctx_t *ctx);

static void
loadmgr_start(isc_task_t *task, isc_event_t *event);

static void
loadmgr_cancel(dns_loadmgr_t *mgr);

static void
loadmgr_iattach(dns_loadmgr_t *source, dns_loadmgr_t **target);

static void
loadmgr_idetach(dns_loadmgr_t **mgrp);

static void
loadmgr_destroy(dns_loadmgr_t *mgr);

#define GETTOKEN(lexer, options, token, eol) \
	do { \
		result = gettoken(lexer, options, token, eol, callbacks); \
		switch (result) { \
		case ISC_R_SUCCESS: \
			break; \
		case ISC_R_UNEXPECTED: \
			goto insist_and_cleanup; \
		default: \
			goto log_and_cleanup; \
		} \
		if ((token)->type == isc_tokentype_special) { \
			result = DNS_R_SYNTAX; \
			goto log_and_cleanup; \
		} \
	} while (0)

#define COMMITALL \
	do { \
		result = commit(callbacks, ctx->lex, &current_list, \
				ctx->current, ctx->top); \
		if (result != ISC_R_SUCCESS) \
			goto insist_and_cleanup; \
		result = commit(callbacks, ctx->lex, &glue_list, \
				ctx->glue, ctx->top); \
		if (result != ISC_R_SUCCESS) \
			goto insist_and_cleanup; \
		rdcount = 0; \
		rdlcount = 0; \
		isc_buffer_init(&target, target_mem, target_size); \
		rdcount_save = rdcount; \
		rdlcount_save = rdlcount; \
	} while (0)

#define WARNUNEXPECTEDEOF(lexer) \
	do { \
		if (isc_lex_isfile(lexer)) \
			(*callbacks->warn)(callbacks, \
				"%s:%lu: file does not end with newline", \
				isc_lex_getsourcename(lexer), \
				isc_lex_getsourceline(lexer)); \
	} while (0)

#define CTX_COPYVAR(ctx, new, var) (new)->var = (ctx)->var

static inline isc_result_t
gettoken(isc_lex_t *lex, unsigned int options, isc_token_t *token,
	 isc_boolean_t eol, dns_rdatacallbacks_t *callbacks)
{
	isc_result_t result;

	options |= ISC_LEXOPT_EOL | ISC_LEXOPT_EOF | ISC_LEXOPT_DNSMULTILINE |
		ISC_LEXOPT_ESCAPE;
	result = isc_lex_gettoken(lex, options, token);
	if (result != ISC_R_SUCCESS) {
		switch (result) {
		case ISC_R_NOMEMORY:
			return (ISC_R_NOMEMORY);
		default:
			UNEXPECTED_ERROR(__FILE__, __LINE__,
				"isc_lex_gettoken() failed: %s",
				isc_result_totext(result));
			return (ISC_R_UNEXPECTED);
		}
		/*NOTREACHED*/
	}
	if (eol != ISC_TRUE)
		if (token->type == isc_tokentype_eol ||
		    token->type == isc_tokentype_eof) {
			(*callbacks->error)(callbacks,
			    "dns_master_load: %s:%lu: unexpected end of %s",
					    isc_lex_getsourcename(lex),
					    isc_lex_getsourceline(lex),
					    (token->type ==
					     isc_tokentype_eol) ?
					    "line" : "file");
			return (ISC_R_UNEXPECTEDEND);
		}
	return (ISC_R_SUCCESS);
}


void
dns_loadctx_attach(dns_loadctx_t *source, dns_loadctx_t **target) {

	REQUIRE(target != NULL && *target == NULL);
	REQUIRE(DNS_LCTX_VALID(source));

	LOCK(&source->lock);
	INSIST(source->references > 0);
	source->references++;
	INSIST(source->references != 0);	/* Overflow? */
	UNLOCK(&source->lock);

	*target = source;
}

void
dns_loadctx_detach(dns_loadctx_t **ctxp) {
	dns_loadctx_t *ctx;
	isc_boolean_t need_destroy = ISC_FALSE;

	REQUIRE(ctxp != NULL);
	ctx = *ctxp;
	REQUIRE(DNS_LCTX_VALID(ctx));

	LOCK(&ctx->lock);
	INSIST(ctx->references > 0);
	ctx->references--;
	if (ctx->references == 0)
		need_destroy = ISC_TRUE;
	UNLOCK(&ctx->lock);

	if (need_destroy)
		loadctx_destroy(ctx);
	*ctxp = NULL;
}

static void
loadctx_destroy(dns_loadctx_t *ctx) {
	isc_mem_t *mctx;

	REQUIRE(DNS_LCTX_VALID(ctx));

	ctx->magic = 0;
	if (ctx->parent != NULL)
		dns_loadctx_detach(&ctx->parent);

	if (ctx->lex != NULL) {
		isc_lex_close(ctx->lex);
		isc_lex_destroy(&ctx->lex);
	}
	if (ctx->task != NULL)
		isc_task_detach(&ctx->task);
	if (ctx->master_file != NULL) {
		isc_mem_free(ctx->mctx, ctx->master_file);
		ctx->master_file = NULL;
	}
	if (ctx->loadmgr != NULL)
		loadmgr_idetach(&ctx->loadmgr);
	DESTROYLOCK(&ctx->lock);
	mctx = NULL;
	isc_mem_attach(ctx->mctx, &mctx);
	isc_mem_detach(&ctx->mctx);
	isc_mem_put(mctx, ctx, sizeof(*ctx));
	isc_mem_detach(&mctx);
}

static isc_result_t
loadctx_create(isc_mem_t *mctx, isc_boolean_t age_ttl, dns_name_t *top,
	       dns_rdataclass_t zclass, dns_name_t *origin,
	       dns_rdatacallbacks_t *callbacks, isc_task_t *task,
	       dns_loaddonefunc_t done, void *done_arg,
	       dns_loadctx_t **ctxp)
{
	dns_loadctx_t *ctx;
	isc_result_t result;
	isc_region_t r;
	int i;
	isc_lexspecials_t specials;

	REQUIRE(ctxp != NULL && *ctxp == NULL);
	REQUIRE(callbacks != NULL);
	REQUIRE(callbacks->add != NULL);
	REQUIRE(callbacks->error != NULL);
	REQUIRE(callbacks->warn != NULL);
	REQUIRE(mctx != NULL);
	REQUIRE(dns_name_isabsolute(top));
	REQUIRE(dns_name_isabsolute(origin));
	REQUIRE((task == NULL && done == NULL) ||
		(task != NULL && done != NULL));

	ctx = isc_mem_get(mctx, sizeof(*ctx));
	if (ctx == NULL)
		return (ISC_R_NOMEMORY);
	result = isc_mutex_init(&ctx->lock);
	if (result != ISC_R_SUCCESS) {
		isc_mem_put(mctx, ctx, sizeof *ctx);
		UNEXPECTED_ERROR(__FILE__, __LINE__,
				 "isc_mutex_init() failed: %s",
				 isc_result_totext(result));
		return (ISC_R_UNEXPECTED);
	}

	ctx->lex = NULL;
	result = isc_lex_create(mctx, TOKENSIZ, &ctx->lex);
	if (result != ISC_R_SUCCESS)
		goto cleanup_ctx;
	memset(specials, 0, sizeof specials);
	specials['('] = 1;
	specials[')'] = 1;
	specials['"'] = 1;
	isc_lex_setspecials(ctx->lex, specials);
	isc_lex_setcomments(ctx->lex, ISC_LEXCOMMENT_DNSMASTERFILE);

	ctx->ttl_known = ISC_FALSE;
	ctx->ttl = 0;
	ctx->default_ttl_known = ISC_FALSE;
	ctx->default_ttl = 0;
	ctx->warn_1035 = ISC_TRUE;	/* XXX Argument? */
	ctx->age_ttl = age_ttl;
	ctx->seen_include = ISC_FALSE;
	ctx->zclass = zclass;

	dns_fixedname_init(&ctx->fixed_top);
	ctx->top = dns_fixedname_name(&ctx->fixed_top);
	dns_name_toregion(top, &r);
	dns_name_fromregion(ctx->top, &r);

	for (i = 0; i < NBUFS; i++) {
		dns_fixedname_init(&ctx->fixed[i]);
		ctx->in_use[i] = ISC_FALSE;
	}

	ctx->origin_in_use = 0;
	ctx->origin = dns_fixedname_name(&ctx->fixed[ctx->origin_in_use]);
	ctx->in_use[ctx->origin_in_use] = ISC_TRUE;
	dns_name_toregion(origin, &r);
	dns_name_fromregion(ctx->origin, &r);

	ctx->glue = NULL;
	ctx->current = NULL;
	ctx->glue_in_use = -1;
	ctx->current_in_use = -1;
	ctx->loop_cnt = (done != NULL) ? 100 : 0;
	ctx->callbacks = callbacks;
	ctx->parent = NULL;
	ctx->task = NULL;
	if (task != NULL)
		isc_task_attach(task, &ctx->task);
	ctx->done = done;
	ctx->done_arg = done_arg;

	ctx->rate_limited = ISC_FALSE;
	ctx->master_file = NULL;
	ctx->loadmgr = NULL;
	ISC_LINK_INIT(ctx, link);
	ISC_EVENT_INIT(&ctx->event, sizeof(ctx->event), 0, NULL,
		       DNS_EVENT_MASTERNEXTZONE, loadmgr_start,
		       ctx, ctx, NULL, NULL);

	ctx->canceled = ISC_FALSE;
	ctx->mctx = NULL;
	isc_mem_attach(mctx, &ctx->mctx);
	ctx->references = 1;			/* Implicit attach. */
	ctx->magic = DNS_LCTX_MAGIC;
	*ctxp = ctx;
	return (ISC_R_SUCCESS);

 cleanup_ctx:
	isc_mem_put(mctx, ctx, sizeof(*ctx));
	return (result);
}

static isc_result_t
genname(char *name, int it, char *buffer, size_t length) {
	char fmt[sizeof("%04000000000d")];
	char numbuf[128];
	char *cp;
	char mode;
	int delta = 0;
	isc_textregion_t r;
	unsigned int n;
	unsigned int width;

	r.base = buffer;
	r.length = length;

	while (*name != '\0') {
		if (*name == '$') {
			name++;
			strcpy(fmt, "%d");
			/* Get format specifier. */
			if (*name == '{' ) {
				n = sscanf(name, "{%d,%u,%1[doxX]}",
					   &delta, &width, &mode);
				switch (n) {
				case 1:
					break;
				case 2:
					n = snprintf(fmt, sizeof(fmt),
						     "%%0%ud", width);
					break;
				case 3:
					n = snprintf(fmt, sizeof(fmt),
						     "%%0%u%c", width, mode);
					break;
				default:
					return (DNS_R_SYNTAX);
				}
				if (n >= sizeof(fmt))
					return (ISC_R_NOSPACE);
				/* Skip past closing brace. */
				while (*name != '\0' && *name++ != '}')
					continue;
			}
			n = snprintf(numbuf, sizeof(numbuf), fmt, it + delta);
			if (n >= sizeof(numbuf))
				return (ISC_R_NOSPACE);
			cp = numbuf;
			while (*cp != '\0') {
				if (r.length == 0)
					return (ISC_R_NOSPACE);
				r.base[0] = *cp++;
				isc_textregion_consume(&r, 1);
			}
		} else if (*name == '\\') {
			if (r.length == 0)
				return (ISC_R_NOSPACE);
			r.base[0] = *name++;
			isc_textregion_consume(&r, 1);
			if (*name == '\0')
				continue;
			if (r.length == 0)
				return (ISC_R_NOSPACE);
			r.base[0] = *name++;
			isc_textregion_consume(&r, 1);
		} else {
			if (r.length == 0)
				return (ISC_R_NOSPACE);
			r.base[0] = *name++;
			isc_textregion_consume(&r, 1);
		}
	}
	if (r.length == 0)
		return (ISC_R_NOSPACE);
	r.base[0] = '\0';
	return (ISC_R_SUCCESS);
}

static isc_result_t
generate(dns_loadctx_t *ctx, char *range, char *lhs, char *gtype, char *rhs) {
	char *target_mem = NULL;
	char *lhsbuf = NULL;
	char *rhsbuf = NULL;
	dns_fixedname_t ownerfixed;
	dns_name_t *owner;
	dns_rdata_t rdata;
	dns_rdatacallbacks_t *callbacks;
	dns_rdatalist_t rdatalist;
	dns_rdatatype_t type;
	rdatalist_head_t head;
	int n;
	int target_size = MINTSIZ;	/* only one rdata at a time */
	isc_buffer_t buffer;
	isc_buffer_t target;
	isc_result_t result;
	isc_textregion_t r;
	unsigned int start, stop, step, i;

	callbacks = ctx->callbacks;
	dns_fixedname_init(&ownerfixed);
	owner = dns_fixedname_name(&ownerfixed);
	ISC_LIST_INIT(head);

	target_mem = isc_mem_get(ctx->mctx, target_size);
	rhsbuf = isc_mem_get(ctx->mctx, DNS_MASTER_BUFSZ);
	lhsbuf = isc_mem_get(ctx->mctx, DNS_MASTER_BUFSZ);
	if (target_mem == NULL || rhsbuf == NULL || lhsbuf == NULL) {
		result = ISC_R_NOMEMORY;
		goto error_cleanup;
	}
	isc_buffer_init(&target, target_mem, target_size);

	n = sscanf(range, "%u-%u/%u", &start, &stop, &step);
	if (n < 2 || stop < stop) {
	       (*callbacks->warn)(callbacks,
				  "%s: %s:%lu: invalid range '%s'",
				  "$GENERATE",
				  isc_lex_getsourcename(ctx->lex),
				  isc_lex_getsourceline(ctx->lex),
				  range);
		result = DNS_R_SYNTAX;
		goto insist_cleanup;
	}
	if (n == 2)
		step = 1;

	/*
	 * Get type.
	 */
	r.base = gtype;
	r.length = strlen(gtype);
	result = dns_rdatatype_fromtext(&type, &r);
	if (result != ISC_R_SUCCESS) {
		(*callbacks->warn)(callbacks,
				   "%s: %s:%lu: unknown RR type '%s'",
				   "$GENERATE",
				   isc_lex_getsourcename(ctx->lex),
				   isc_lex_getsourceline(ctx->lex),
				   gtype);
		goto insist_cleanup;
	}

	switch (type) {
	case dns_rdatatype_ns:
	case dns_rdatatype_ptr:
	case dns_rdatatype_cname:
		break;

	case dns_rdatatype_a:
	case dns_rdatatype_aaaa:
		if (ctx->zclass == dns_rdataclass_in ||
		    ctx->zclass == dns_rdataclass_hs)
			break;
		/* FALLTHROUGH */
	default:
	       (*callbacks->warn)(callbacks,
				  "%s: %s:%lu: unsupported type '%s'",
				  "$GENERATE",
				  isc_lex_getsourcename(ctx->lex),
				  isc_lex_getsourceline(ctx->lex),
				  gtype);
		result = ISC_R_NOTIMPLEMENTED;
		goto error_cleanup;
	}

	for (i = start; i < stop; i += step) {
		result = genname(lhs, i, lhsbuf, DNS_MASTER_BUFSZ);
		if (result != ISC_R_SUCCESS)
			goto error_cleanup;
		result = genname(rhs, i, rhsbuf, DNS_MASTER_BUFSZ);
		if (result != ISC_R_SUCCESS)
			goto error_cleanup;

		isc_buffer_init(&buffer, lhsbuf, strlen(lhsbuf));
		isc_buffer_add(&buffer, strlen(lhsbuf));
		isc_buffer_setactive(&buffer, strlen(lhsbuf));
		result = dns_name_fromtext(owner, &buffer, ctx->origin,
					   ISC_FALSE, NULL);
		if (result != ISC_R_SUCCESS)
			goto error_cleanup;

		isc_buffer_init(&buffer, rhsbuf, strlen(rhsbuf));
		isc_buffer_add(&buffer, strlen(rhsbuf));
		isc_buffer_setactive(&buffer, strlen(rhsbuf));

		result = isc_lex_openbuffer(ctx->lex, &buffer);
		if (result != ISC_R_SUCCESS)
			goto error_cleanup;

		isc_buffer_init(&target, target_mem, target_size);
		result = dns_rdata_fromtext(&rdata, ctx->zclass, type,
					    ctx->lex, ctx->origin, ISC_FALSE,
					    &target, callbacks);
		isc_lex_close(ctx->lex);
		if (result != ISC_R_SUCCESS)
			goto error_cleanup;

		rdatalist.type = type;
		rdatalist.covers = 0;
		rdatalist.rdclass = ctx->zclass;
		rdatalist.ttl = ctx->ttl;
		ISC_LIST_INIT(rdatalist.rdata);
		ISC_LIST_PREPEND(head, &rdatalist, link);
		ISC_LIST_APPEND(rdatalist.rdata, &rdata, link);
		result = commit(callbacks, ctx->lex, &head, owner,
				ctx->top);
		if (result != ISC_R_SUCCESS)
			goto error_cleanup;
	}
	result = ISC_R_SUCCESS;
	goto cleanup;

 error_cleanup:
	if (result == ISC_R_NOMEMORY)
		(*callbacks->error)(callbacks, "$GENERATE: %s",
				    dns_result_totext(result));
	else
		(*callbacks->error)(callbacks, "$GENERATE: %s:%lu: %s",
				    isc_lex_getsourcename(ctx->lex),
				    isc_lex_getsourceline(ctx->lex),
				    dns_result_totext(result));

 insist_cleanup:
	INSIST(result != ISC_R_SUCCESS);

 cleanup:
	if (target_mem != NULL)
		isc_mem_put(ctx->mctx, target_mem, target_size);
	if (lhsbuf != NULL)
		isc_mem_put(ctx->mctx, lhsbuf, DNS_MASTER_BUFSZ);
	if (rhsbuf != NULL)
		isc_mem_put(ctx->mctx, rhsbuf, DNS_MASTER_BUFSZ);
	return (result);
}

static isc_result_t
load(dns_loadctx_t **ctxp) {
	dns_rdataclass_t rdclass;
	dns_rdatatype_t type, covers;
	isc_uint32_t ttl_offset = 0;
	dns_name_t *new_name;
	isc_boolean_t current_has_delegation = ISC_FALSE;
	isc_boolean_t done = ISC_FALSE;
	isc_boolean_t finish_origin = ISC_FALSE;
	isc_boolean_t finish_include = ISC_FALSE;
	isc_boolean_t read_till_eol = ISC_FALSE;
	isc_boolean_t initialws;
	char *include_file = NULL;
	isc_token_t token;
	isc_result_t result = ISC_R_UNEXPECTED;
	rdatalist_head_t glue_list;
	rdatalist_head_t current_list;
	dns_rdatalist_t *this;
	dns_rdatalist_t *rdatalist = NULL;
	dns_rdatalist_t *new_rdatalist;
	int rdlcount = 0;
	int rdlcount_save = 0;
	int rdatalist_size = 0;
	isc_buffer_t buffer;
	isc_buffer_t target;
	isc_buffer_t target_save;
	dns_rdata_t *rdata = NULL;
	dns_rdata_t *new_rdata;
	int rdcount = 0;
	int rdcount_save = 0;
	int rdata_size = 0;
	unsigned char *target_mem = NULL;
	int target_size = TSIZ;
	int new_in_use;
	unsigned int loop_cnt = 0;
	isc_mem_t *mctx;
	dns_rdatacallbacks_t *callbacks;
	dns_loadctx_t *ctx;
	char *range = NULL;
	char *lhs = NULL;
	char *gtype = NULL;
	char *rhs = NULL;


	ctx = *ctxp;
	REQUIRE(DNS_LCTX_VALID(ctx));
	callbacks = ctx->callbacks;
	mctx = ctx->mctx;

	ISC_LIST_INIT(glue_list);
	ISC_LIST_INIT(current_list);

	/*
	 * Allocate target_size of buffer space.  This is greater than twice
	 * the maximum individual RR data size.
	 */
	target_mem = isc_mem_get(mctx, target_size);
	if (target_mem == NULL) {
		result = ISC_R_NOMEMORY;
		goto log_and_cleanup;
	}
	isc_buffer_init(&target, target_mem, target_size);
	target_save = target;

	do {
		initialws = ISC_FALSE;
		GETTOKEN(ctx->lex, ISC_LEXOPT_INITIALWS, &token, ISC_TRUE);

		if (token.type == isc_tokentype_eof) {
			if (read_till_eol)
				WARNUNEXPECTEDEOF(ctx->lex);
			/* Pop the include stack? */
			if (ctx->parent != NULL) {
				COMMITALL;
				*ctxp = ctx->parent;
				ctx->parent = NULL;
				CTX_COPYVAR(ctx, *ctxp, ttl_known);
				CTX_COPYVAR(ctx, *ctxp, default_ttl_known);
				CTX_COPYVAR(ctx, *ctxp, ttl);
				CTX_COPYVAR(ctx, *ctxp, default_ttl);
				CTX_COPYVAR(ctx, *ctxp, warn_1035);
				CTX_COPYVAR(ctx, *ctxp, seen_include);
				dns_loadctx_detach(&ctx);
				ctx = *ctxp;
				continue;
			}
			done = ISC_TRUE;
			continue;
		}

		if (token.type == isc_tokentype_eol) {
			read_till_eol = ISC_FALSE;
			continue;		/* blank line */
		}

		if (read_till_eol)
			continue;

		if (token.type == isc_tokentype_initialws) {
			/*
			 * Still working on the same name.
			 */
			initialws = ISC_TRUE;
		} else if (token.type == isc_tokentype_string) {

			/*
			 * "$" Support.
			 *
			 * "$ORIGIN" and "$INCLUDE" can both take domain names.
			 * The processing of "$ORIGIN" and "$INCLUDE" extends
			 * across the normal domain name processing.
			 */

			if (strcasecmp(token.value.as_pointer,
				       "$ORIGIN") == 0) {
				GETTOKEN(ctx->lex, 0, &token, ISC_FALSE);
				read_till_eol = ISC_TRUE;
				finish_origin = ISC_TRUE;
			} else if (strcasecmp(token.value.as_pointer,
					      "$TTL") == 0) {
				GETTOKEN(ctx->lex, 0, &token, ISC_FALSE);
				result =
				   dns_ttl_fromtext(&token.value.as_textregion,
						    &ctx->ttl);
				if (result != ISC_R_SUCCESS)
					goto insist_and_cleanup;
				if (ctx->ttl > 0x7fffffffUL) {
					(callbacks->warn)(callbacks,
							  "%s: %s:%lu: "
							  "$TTL %lu > MAXTTL, "
							  "setting $TTL to 0",
							  "dns_master_load",
						    isc_lex_getsourcename(ctx->lex),
						    isc_lex_getsourceline(ctx->lex),
						    ctx->ttl);
					ctx->ttl = 0;
				}
				ctx->default_ttl = ctx->ttl;
				ctx->default_ttl_known = ISC_TRUE;
				read_till_eol = ISC_TRUE;
				continue;
			} else if (strcasecmp(token.value.as_pointer,
					      "$INCLUDE") == 0) {
				COMMITALL;
				if (ttl_offset != 0) {
					(callbacks->error)(callbacks,
					   "%s: %s:%lu: $INCLUDE "
					   "may not be used with $DATE",
					   "dns_master_load",
					   isc_lex_getsourcename(ctx->lex),
					   isc_lex_getsourceline(ctx->lex));
					result = DNS_R_SYNTAX;
					goto insist_and_cleanup;
				}
				GETTOKEN(ctx->lex, ISC_LEXOPT_QSTRING, &token,
					 ISC_FALSE);
				if (include_file != NULL)
					isc_mem_free(mctx, include_file);
				include_file = isc_mem_strdup(mctx,
						token.value.as_pointer);
				if (include_file == NULL) {
					result = ISC_R_NOMEMORY;
					goto log_and_cleanup;
				}
				GETTOKEN(ctx->lex, 0, &token, ISC_TRUE);

				if (token.type == isc_tokentype_eol ||
				    token.type == isc_tokentype_eof) {
					if (token.type == isc_tokentype_eof)
						WARNUNEXPECTEDEOF(ctx->lex);
					isc_lex_ungettoken(ctx->lex, &token);
					/*
					 * No origin field.
					 */
					result = pushfile(include_file,
							  ctx->origin,
							  ctxp);
					if (result != ISC_R_SUCCESS)
						goto log_and_cleanup;
					ctx = *ctxp;
					continue;
				}
				/*
				 * There is an origin field.  Fall through
				 * to domain name processing code and do
				 * the actual inclusion later.
				 */
				read_till_eol = ISC_TRUE;
				finish_include = ISC_TRUE;
			} else if (strcasecmp(token.value.as_pointer,
					      "$DATE") == 0) {
				isc_int64_t dump_time64;
				isc_stdtime_t dump_time, current_time;
				GETTOKEN(ctx->lex, 0, &token, ISC_FALSE);
				isc_stdtime_get(&current_time);
				result = dns_time64_fromtext(token.value.
					     as_pointer, &dump_time64);
				if (result != ISC_R_SUCCESS)
					goto log_and_cleanup;
				dump_time = (isc_stdtime_t)dump_time64;
				if (dump_time != dump_time64) {
					UNEXPECTED_ERROR(__FILE__, __LINE__,
					 "%s: %s:%lu: "
					 "$DATE outside epoch",
					 "dns_master_load",
					 isc_lex_getsourcename(ctx->lex),
					 isc_lex_getsourceline(ctx->lex));
					result = ISC_R_UNEXPECTED;
					goto insist_and_cleanup;
				}
				if (dump_time > current_time) {
					UNEXPECTED_ERROR(__FILE__, __LINE__,
					"%s: %s:%lu: "
					"$DATE in future, using current date",
					"dns_master_load",
					isc_lex_getsourcename(ctx->lex),
					isc_lex_getsourceline(ctx->lex));
					dump_time = current_time;
				}
				ttl_offset = current_time - dump_time;
				read_till_eol = ISC_TRUE;
				continue;
			} else if (strcasecmp(token.value.as_pointer,
					      "$GENERATE") == 0) {
				/*
				 * Use default ttl if known otherwise
				 * inherit or error.
				 */
				if (!ctx->ttl_known &&
				    !ctx->default_ttl_known) {
					(*callbacks->error)(callbacks,
					    "%s: %s:%lu: no TTL specified",
					    "dns_master_load",
					    isc_lex_getsourcename(ctx->lex),
					    isc_lex_getsourceline(ctx->lex));
					result = DNS_R_NOTTL;
					goto insist_and_cleanup;
				} else if (ctx->default_ttl_known) {
					ctx->ttl = ctx->default_ttl;
				}
				/*
				 * Lazy cleanup.
				 */
				if (range != NULL)
					isc_mem_free(mctx, range);
				if (lhs != NULL)
					isc_mem_free(mctx, lhs);
				if (gtype != NULL)
					isc_mem_free(mctx, gtype);
				if (rhs != NULL)
					isc_mem_free(mctx, rhs);
				/* range */
				GETTOKEN(ctx->lex, 0, &token, ISC_FALSE);
				range = isc_mem_strdup(mctx,
						     token.value.as_pointer);
				if (range == NULL) {
					result = ISC_R_NOMEMORY;
					goto log_and_cleanup;
				}
				/* LHS */
				GETTOKEN(ctx->lex, 0, &token, ISC_FALSE);
				lhs = isc_mem_strdup(mctx,
						    token.value.as_pointer);
				if (lhs == NULL) {
					result = ISC_R_NOMEMORY;
					goto log_and_cleanup;
				}
				/* TYPE */
				GETTOKEN(ctx->lex, 0, &token, ISC_FALSE);
				gtype = isc_mem_strdup(mctx,
						       token.value.as_pointer);
				if (gtype == NULL) {
					result = ISC_R_NOMEMORY;
					goto log_and_cleanup;
				}
				/* RHS */
				GETTOKEN(ctx->lex, 0, &token, ISC_FALSE);
				rhs = isc_mem_strdup(mctx,
						     token.value.as_pointer);
				if (rhs == NULL) {
					result = ISC_R_NOMEMORY;
					goto log_and_cleanup;
				}
				result = generate(ctx, range, lhs, gtype, rhs);
				if (result != ISC_R_SUCCESS)
					goto insist_and_cleanup;
				read_till_eol = ISC_TRUE;
				continue;
			} else if (strncasecmp(token.value.as_pointer,
					       "$", 1) == 0) {
				(callbacks->error)(callbacks,
						   "%s: %s:%lu: "
						   "unknown $ directive '%s'",
						   "dns_master_load",
						   isc_lex_getsourcename(ctx->lex),
						   isc_lex_getsourceline(ctx->lex),
						   token.value.as_pointer);
				result = DNS_R_SYNTAX;
				goto insist_and_cleanup;
			}

			/*
			 * Normal processing resumes.
			 *
			 * Find a free name buffer.
			 */
			for (new_in_use = 0; new_in_use < NBUFS ; new_in_use++)
				if (!ctx->in_use[new_in_use])
					break;
			INSIST(new_in_use < NBUFS);
			dns_fixedname_init(&ctx->fixed[new_in_use]);
			new_name = dns_fixedname_name(&ctx->fixed[new_in_use]);
			isc_buffer_init(&buffer, token.value.as_region.base,
					token.value.as_region.length);
			isc_buffer_add(&buffer, token.value.as_region.length);
			isc_buffer_setactive(&buffer,
					     token.value.as_region.length);
			result = dns_name_fromtext(new_name, &buffer,
					  ctx->origin, ISC_FALSE, NULL);
			if (result != ISC_R_SUCCESS)
				goto log_and_cleanup;

			/*
			 * Finish $ORIGIN / $INCLUDE processing if required.
			 */
			if (finish_origin) {
				if (ctx->origin_in_use != -1)
					ctx->in_use[ctx->origin_in_use] = ISC_FALSE;
				ctx->origin_in_use = new_in_use;
				ctx->in_use[ctx->origin_in_use] = ISC_TRUE;
				ctx->origin = new_name;
				finish_origin = ISC_FALSE;
				continue;
			}
			if (finish_include) {
				finish_include = ISC_FALSE;
				result = pushfile(include_file, new_name, ctxp);
				if (result != ISC_R_SUCCESS)
					goto log_and_cleanup;
				ctx = *ctxp;
				continue;
			}

			/*
			 * "$" Processing Finished
			 */

			/*
			 * If we are processing glue and the new name does
			 * not match the current glue name, commit the glue
			 * and pop stacks leaving us in 'normal' processing
			 * state.  Linked lists are undone by commit().
			 */
			if (ctx->glue != NULL &&
			    dns_name_compare(ctx->glue, new_name) != 0) {
				result = commit(callbacks, ctx->lex, &glue_list,
						ctx->glue, ctx->top);
				if (result != ISC_R_SUCCESS)
					goto insist_and_cleanup;
				if (ctx->glue_in_use != -1)
					ctx->in_use[ctx->glue_in_use] = ISC_FALSE;
				ctx->glue_in_use = -1;
				ctx->glue = NULL;
				rdcount = rdcount_save;
				rdlcount = rdlcount_save;
				target = target_save;
			}

			/*
			 * If we are in 'normal' processing state and the new
			 * name does not match the current name, see if the
			 * new name is for glue and treat it as such,
			 * otherwise we have a new name so commit what we
			 * have.
			 */
			if ((ctx->glue == NULL) && (ctx->current == NULL ||
			    dns_name_compare(ctx->current, new_name) != 0)) {
				if (current_has_delegation &&
					is_glue(&current_list, new_name)) {
					rdcount_save = rdcount;
					rdlcount_save = rdlcount;
					target_save = target;
					ctx->glue = new_name;
					ctx->glue_in_use = new_in_use;
					ctx->in_use[ctx->glue_in_use] = ISC_TRUE;
				} else {
					result = commit(callbacks, ctx->lex,
							&current_list,
							ctx->current,
							ctx->top);
					if (result != ISC_R_SUCCESS)
						goto insist_and_cleanup;
					rdcount = 0;
					rdlcount = 0;
					if (ctx->current_in_use != -1)
						ctx->in_use[ctx->current_in_use]
							= ISC_FALSE;
					ctx->current_in_use = new_in_use;
					ctx->in_use[ctx->current_in_use] = ISC_TRUE;
					ctx->current = new_name;
					current_has_delegation = ISC_FALSE;
					isc_buffer_init(&target, target_mem,
							target_size);
				}
			}
		} else {
			UNEXPECTED_ERROR(__FILE__, __LINE__,
					 "%s:%lu: isc_lex_gettoken() returned "
					 "unexpeced token type (%d)",
					 isc_lex_getsourcename(ctx->lex),
					 isc_lex_getsourceline(ctx->lex),
					 token.type);
			result = ISC_R_UNEXPECTED;
			goto insist_and_cleanup;
		}

		/*
		 * Find TTL, class and type.  Both TTL and class are optional
		 * and may occur in any order if they exist. TTL and class
		 * come before type which must exist.
		 *
		 * [<TTL>] [<class>] <type> <RDATA>
		 * [<class>] [<TTL>] <type> <RDATA>
		 */

		type = 0;
		rdclass = 0;

		GETTOKEN(ctx->lex, 0, &token, initialws);

		if (initialws) {
			if (token.type == isc_tokentype_eol) {
				read_till_eol = ISC_FALSE;
				continue;		/* blank line */
			}

			if (token.type == isc_tokentype_eof) {
				WARNUNEXPECTEDEOF(ctx->lex);
				read_till_eol = ISC_FALSE;
				isc_lex_ungettoken(ctx->lex, &token);
				continue;
			}

			if (ctx->current == NULL) {
				(*callbacks->error)(callbacks,
					"%s: %s:%lu: No current owner name",
						"dns_master_load",
						isc_lex_getsourcename(ctx->lex),
						isc_lex_getsourceline(ctx->lex));
				result = DNS_R_NOOWNER;
				goto insist_and_cleanup;
			}
		}

		if (dns_rdataclass_fromtext(&rdclass,
					    &token.value.as_textregion)
				== ISC_R_SUCCESS)
			GETTOKEN(ctx->lex, 0, &token, ISC_FALSE);

		if (dns_ttl_fromtext(&token.value.as_textregion, &ctx->ttl)
				== ISC_R_SUCCESS) {
			if (ctx->ttl > 0x7fffffffUL) {
				(callbacks->warn)(callbacks,
						  "%s: %s:%lu: "
						  "TTL %lu > MAXTTL, "
						  "setting TTL to 0",
						  "dns_master_load",
						  isc_lex_getsourcename(ctx->lex),
						  isc_lex_getsourceline(ctx->lex),
						  ctx->ttl);
				ctx->ttl = 0;
			}
			ctx->ttl_known = ISC_TRUE;
			GETTOKEN(ctx->lex, 0, &token, ISC_FALSE);
		} else if (!ctx->ttl_known && !ctx->default_ttl_known) {
			/*
			 * BIND 4 / 8 'USE_SOA_MINIMUM' could be set here.
			 */
			(*callbacks->error)(callbacks,
					    "%s: %s:%lu: no TTL specified",
					    "dns_master_load",
					    isc_lex_getsourcename(ctx->lex),
					    isc_lex_getsourceline(ctx->lex));
			result = DNS_R_NOTTL;
			goto insist_and_cleanup;
		} else if (ctx->default_ttl_known) {
			ctx->ttl = ctx->default_ttl;
		} else if (ctx->warn_1035) {
			(*callbacks->warn)(callbacks,
					   "%s: %s:%lu: "
					   "using RFC 1035 TTL semantics",
					   "dns_master_load",
					   isc_lex_getsourcename(ctx->lex),
					   isc_lex_getsourceline(ctx->lex));
			ctx->warn_1035 = ISC_FALSE;
		}

		if (token.type != isc_tokentype_string) {
			UNEXPECTED_ERROR(__FILE__, __LINE__,
			"isc_lex_gettoken() returned unexpected token type");
			result = ISC_R_UNEXPECTED;
			goto insist_and_cleanup;
		}

		if (rdclass == 0 &&
		    dns_rdataclass_fromtext(&rdclass,
					    &token.value.as_textregion)
				== ISC_R_SUCCESS)
			GETTOKEN(ctx->lex, 0, &token, ISC_FALSE);

		if (token.type !=  isc_tokentype_string) {
			UNEXPECTED_ERROR(__FILE__, __LINE__,
			"isc_lex_gettoken() returned unexpected token type");
			result = ISC_R_UNEXPECTED;
			goto insist_and_cleanup;
		}

		result = dns_rdatatype_fromtext(&type,
						&token.value.as_textregion);
		if (result != ISC_R_SUCCESS) {
			(*callbacks->warn)(callbacks,
					   "%s: %s:%lu: unknown RR type '%.*s'",
					   "dns_master_load",
					   isc_lex_getsourcename(ctx->lex),
					   isc_lex_getsourceline(ctx->lex),
					   token.value.as_textregion.length,
					   token.value.as_textregion.base);
			goto insist_and_cleanup;
		}

		/*
		 * If the class specified does not match the zone's class
		 * print out a error message and exit.
		 */
		if (rdclass != 0 && rdclass != ctx->zclass) {
			char buf1[32];
			char buf2[32];
			unsigned int len1, len2;
			isc_buffer_t buffer;
			isc_region_t region;

			isc_buffer_init(&buffer, buf1, sizeof(buf1));
			result = dns_rdataclass_totext(rdclass, &buffer);
			if (result != ISC_R_SUCCESS) {
				UNEXPECTED_ERROR(__FILE__, __LINE__,
					"dns_rdataclass_totext() failed: %s",
						 dns_result_totext(result));
				result = ISC_R_UNEXPECTED;
				goto insist_and_cleanup;
			}
			isc_buffer_usedregion(&buffer, &region);
			len1 = region.length;
			isc_buffer_init(&buffer, buf2, sizeof(buf2));
			result = dns_rdataclass_totext(ctx->zclass, &buffer);
			if (result != ISC_R_SUCCESS) {
				UNEXPECTED_ERROR(__FILE__, __LINE__,
					"dns_rdataclass_totext() failed: %s",
						 dns_result_totext(result));
				result = ISC_R_UNEXPECTED;
				goto insist_and_cleanup;
			}
			isc_buffer_usedregion(&buffer, &region);
			len2 = region.length;
			(*callbacks->error)(callbacks,
					    "%s: %s:%lu: class (%.*s) != "
					    "zone class (%.*s)",
					    "dns_master_load",
					    isc_lex_getsourcename(ctx->lex),
					    isc_lex_getsourceline(ctx->lex),
					    len1, buf1, len2, buf2);
			result = DNS_R_BADCLASS;
			goto insist_and_cleanup;
		}

		if (type == dns_rdatatype_ns && ctx->glue == NULL)
			current_has_delegation = ISC_TRUE;

		if (ctx->age_ttl) {
			/*
			 * Adjust the TTL for $DATE.  If the RR has already
			 * expired, ignore it without even parsing the rdata
			 * part (good for performance, bad for catching
			 * syntax errors).
			 */
			if (ctx->ttl < ttl_offset) {
				read_till_eol = ISC_TRUE;
				continue;
			}
			ctx->ttl -= ttl_offset;
		}

		/*
		 * Find a rdata structure.
		 */
		if (rdcount == rdata_size) {
			new_rdata = grow_rdata(rdata_size + RDSZ, rdata,
					       rdata_size, &current_list,
					       &glue_list, mctx);
			if (new_rdata == NULL) {
				result = ISC_R_NOMEMORY;
				goto log_and_cleanup;
			}
			rdata_size += RDSZ;
			rdata = new_rdata;
		}

		/*
		 * Read rdata contents.
		 */
		dns_rdata_init(&rdata[rdcount]);
		result = dns_rdata_fromtext(&rdata[rdcount], ctx->zclass, type,
				   ctx->lex, ctx->origin, ISC_FALSE, &target,
				   callbacks);
		if (result != ISC_R_SUCCESS)
			goto insist_and_cleanup;
		if (type == dns_rdatatype_sig)
			covers = dns_rdata_covers(&rdata[rdcount]);
		else
			covers = 0;


		/*
		 * Find type in rdatalist.
		 * If it does not exist create new one and prepend to list
		 * as this will mimimise list traversal.
		 */
		if (ctx->glue != NULL)
			this = ISC_LIST_HEAD(glue_list);
		else
			this = ISC_LIST_HEAD(current_list);

		while (this != NULL) {
			if (this->type == type && this->covers == covers)
				break;
			this = ISC_LIST_NEXT(this, link);
		}

		if (this == NULL) {
			if (rdlcount == rdatalist_size) {
				new_rdatalist =
					grow_rdatalist(rdatalist_size + RDLSZ,
						       rdatalist,
						       rdatalist_size,
						       &current_list,
						       &glue_list,
						       mctx);
				if (new_rdatalist == NULL) {
					result = ISC_R_NOMEMORY;
					goto log_and_cleanup;
				}
				rdatalist = new_rdatalist;
				rdatalist_size += RDLSZ;
			}
			this = &rdatalist[rdlcount++];
			this->type = type;
			this->covers = covers;
			this->rdclass = ctx->zclass;
			this->ttl = ctx->ttl;
			ISC_LIST_INIT(this->rdata);
			if (ctx->glue != NULL)
				ISC_LIST_PREPENDUNSAFE(glue_list, this, link);
			else
				ISC_LIST_PREPENDUNSAFE(current_list, this,
						       link);
		} else if (this->ttl != ctx->ttl) {
			(*callbacks->warn)(callbacks,
					   "%s: %s:%lu: "
					   "TTL set to prior TTL (%lu)",
					   "dns_master_load",
					   isc_lex_getsourcename(ctx->lex),
					   isc_lex_getsourceline(ctx->lex),
					   this->ttl);
			ctx->ttl = this->ttl;
		}

		ISC_LIST_APPEND(this->rdata, &rdata[rdcount], link);
		rdcount++;

		/*
		 * We must have at least 64k as rdlen is 16 bits.
		 * If we don't commit everything we have so far.
		 */
		if ((target.length - target.used) < MINTSIZ)
			COMMITALL;
	} while (!done && (ctx->loop_cnt == 0 || ctx->loop_cnt < loop_cnt++));

	/*
	 * Commit what has not yet been committed.
	 */
	result = commit(callbacks, ctx->lex, &current_list, ctx->current, ctx->top);
	if (result != ISC_R_SUCCESS)
		goto insist_and_cleanup;
	result = commit(callbacks, ctx->lex, &glue_list, ctx->glue, ctx->top);
	if (result != ISC_R_SUCCESS)
		goto insist_and_cleanup;
	else
		result = ISC_R_SUCCESS;

	if (!done) {
		INSIST(ctx->done != NULL && ctx->task != NULL);
		result = DNS_R_CONTINUE;
	} else if (result == ISC_R_SUCCESS && ctx->seen_include)
		result = DNS_R_SEENINCLUDE;
	goto cleanup;

 log_and_cleanup:
	if (result == ISC_R_NOMEMORY)
		(*callbacks->error)(callbacks, "dns_master_load: %s",
				    dns_result_totext(result));
	else
		(*callbacks->error)(callbacks, "%s: %s:%lu: %s",
				    "dns_master_load",
				    isc_lex_getsourcename(ctx->lex),
				    isc_lex_getsourceline(ctx->lex),
				    dns_result_totext(result));

 insist_and_cleanup:
	INSIST(result != ISC_R_SUCCESS);

 cleanup:
	while ((this = ISC_LIST_HEAD(current_list)) != NULL)
		ISC_LIST_UNLINK(current_list, this, link);
	while ((this = ISC_LIST_HEAD(glue_list)) != NULL)
		ISC_LIST_UNLINK(glue_list, this, link);
	if (rdatalist != NULL)
		isc_mem_put(mctx, rdatalist,
			    rdatalist_size * sizeof *rdatalist);
	if (rdata != NULL)
		isc_mem_put(mctx, rdata, rdata_size * sizeof *rdata);
	if (target_mem != NULL)
		isc_mem_put(mctx, target_mem, target_size);
	if (include_file != NULL)
		isc_mem_free(mctx, include_file);
	if (range != NULL)
		isc_mem_free(mctx, range);
	if (lhs != NULL)
		isc_mem_free(mctx, lhs);
	if (gtype != NULL)
		isc_mem_free(mctx, gtype);
	if (rhs != NULL)
		isc_mem_free(mctx, rhs);
	return (result);
}

static isc_result_t
pushfile(const char *master_file, dns_name_t *origin, dns_loadctx_t **ctxp) {
	isc_result_t result;
	dns_loadctx_t *ctx;
	dns_loadctx_t *new = NULL;
	isc_region_t r;
	int new_in_use;

	REQUIRE(master_file != NULL);
	REQUIRE(ctxp != NULL);
	ctx = *ctxp;
	REQUIRE(DNS_LCTX_VALID(ctx));

	ctx->seen_include = ISC_TRUE;

	result = loadctx_create(ctx->mctx, ctx->age_ttl, ctx->top,
				ctx->zclass, origin, ctx->callbacks,
				ctx->task, ctx->done, ctx->done_arg,
				&new);
	if (result != ISC_R_SUCCESS)
		return (result);

	/* Set current domain. */
	if (ctx->glue != NULL || ctx->current != NULL) {
		for (new_in_use = 0; new_in_use < NBUFS ; new_in_use++)
			if (!ctx->in_use[new_in_use])
				break;
		INSIST(new_in_use < NBUFS);
		new->current_in_use = new_in_use;
		new->current =
			dns_fixedname_name(&new->fixed[new->current_in_use]);
		new->in_use[ctx->current_in_use] = ISC_TRUE;
		dns_name_toregion((ctx->glue != NULL) ?
				   ctx->glue : ctx->current, &r);
		dns_name_fromregion(new->current, &r);
	}

	CTX_COPYVAR(ctx, new, ttl_known);
	CTX_COPYVAR(ctx, new, default_ttl_known);
	CTX_COPYVAR(ctx, new, ttl);
	CTX_COPYVAR(ctx, new, default_ttl);
	CTX_COPYVAR(ctx, new, warn_1035);
	CTX_COPYVAR(ctx, new, seen_include);

	result = isc_lex_openfile(new->lex, master_file);
	if (result != ISC_R_SUCCESS)
		goto cleanup;
	new->parent = ctx;
	*ctxp = new;
	return (ISC_R_SUCCESS);

 cleanup:
	if (new != NULL)
		dns_loadctx_detach(&new);
	return (result);
}

isc_result_t
dns_master_loadfile(const char *master_file, dns_name_t *top,
		    dns_name_t *origin,
		    dns_rdataclass_t zclass, isc_boolean_t age_ttl,
		    dns_rdatacallbacks_t *callbacks, isc_mem_t *mctx)
{
	dns_loadctx_t *ctx = NULL;
	isc_result_t result;

	result = loadctx_create(mctx, age_ttl, top, zclass, origin,
				callbacks, NULL, NULL, NULL, &ctx);
	if (result != ISC_R_SUCCESS)
		return (result);

	result = isc_lex_openfile(ctx->lex, master_file);
	if (result != ISC_R_SUCCESS)
		goto cleanup;

	result = load(&ctx);
	INSIST(result != DNS_R_CONTINUE);

 cleanup:
	if (ctx != NULL)
		dns_loadctx_detach(&ctx);
	return (result);
}

isc_result_t
dns_master_loadfilequota(const char *master_file, dns_name_t *top,
			 dns_name_t *origin, dns_rdataclass_t zclass,
			 isc_boolean_t age_ttl, dns_rdatacallbacks_t *callbacks,			 isc_task_t *task, dns_loaddonefunc_t done,
			 void *done_arg, dns_loadmgr_t *lmgr,
			 dns_loadctx_t **ctxp, isc_mem_t *mctx)
{
	isc_boolean_t queue;
	dns_loadctx_t *ctx = NULL;
	isc_result_t result;
	isc_event_t *event;

	REQUIRE(DNS_LMGR_VALID(lmgr));
	REQUIRE(ctxp != NULL && *ctxp == NULL);

	result = loadctx_create(mctx, age_ttl, top, zclass, origin,
				callbacks, task, done, done_arg, &ctx);
	if (result != ISC_R_SUCCESS)
		goto cleanup;

	ctx->rate_limited = ISC_TRUE;
	ctx->master_file = isc_mem_strdup(mctx, master_file);
	if (ctx->master_file == NULL) {
		result = ISC_R_NOMEMORY;
		goto cleanup;
	}
	loadmgr_iattach(lmgr, &ctx->loadmgr);

	LOCK(&lmgr->lock);
	lmgr->active++;
	queue = ISC_TF((lmgr->limit != 0 && lmgr->active > lmgr->limit));
	if (queue)
		ISC_LIST_APPEND(lmgr->list, ctx, link);
	INSIST(queue || ISC_LIST_EMPTY(lmgr->list));
	UNLOCK(&lmgr->lock);

	dns_loadctx_attach(ctx, ctxp);
	result = DNS_R_CONTINUE;
	if (!queue) {
		event = &ctx->event;
		isc_task_send(ctx->task, &event);
	}
	return (result);

 cleanup:
	if (ctx != NULL)
		dns_loadctx_detach(&ctx);
	return (result);
}

static void
loadmgr_done(dns_loadctx_t *ctx, isc_result_t result) {
	dns_loadctx_t *next;
	isc_event_t *event;

	if (ctx->done != NULL)
		(ctx->done)(ctx->done_arg, result);

	LOCK(&ctx->loadmgr->lock);
	INSIST(ctx->loadmgr->active > 0);
	ctx->loadmgr->active--;
	/* dequeue */
	next = ISC_LIST_HEAD(ctx->loadmgr->list);
	if (next != NULL)
		ISC_LIST_UNLINK(ctx->loadmgr->list, next, link);
	UNLOCK(&ctx->loadmgr->lock);
	if (next != NULL) {
		event = &next->event;
		isc_task_send(next->task, &event);
	}
}


static void
loadmgr_start(isc_task_t *task, isc_event_t *event) {
	dns_loadctx_t *ctx = event->ev_arg;
	isc_result_t result;

	INSIST(task == ctx->task);

	if ((event->ev_attributes & ISC_EVENTATTR_CANCELED) != 0) {
		result = ISC_R_CANCELED;
		goto done;
	}
	result = isc_lex_openfile(ctx->lex, ctx->master_file);
	if (result == ISC_R_SUCCESS)
		result = load(&ctx);
	if (result == DNS_R_CONTINUE) {
		result = task_send(ctx);
		if (result == ISC_R_SUCCESS)
			isc_event_free(&event);
			return;
	}
 done:
	loadmgr_done(ctx, result);
	isc_event_free(&event);
	dns_loadctx_detach(&ctx);
	return;
}

isc_result_t
dns_master_loadfileinc(const char *master_file, dns_name_t *top,
		       dns_name_t *origin, dns_rdataclass_t zclass,
		       isc_boolean_t age_ttl, dns_rdatacallbacks_t *callbacks,
		       isc_task_t *task, dns_loaddonefunc_t done,
		       void *done_arg, isc_mem_t *mctx)
{
	dns_loadctx_t *ctx = NULL;
	isc_result_t tresult;
	isc_result_t result;

	result = loadctx_create(mctx, age_ttl, top, zclass, origin,
				callbacks, task, done, done_arg, &ctx);
	if (result != ISC_R_SUCCESS)
		return (result);

	result = isc_lex_openfile(ctx->lex, master_file);
	if (result != ISC_R_SUCCESS)
		goto cleanup;

	result = load(&ctx);
	if (result == DNS_R_CONTINUE) {
		tresult = task_send(ctx);
		if (tresult == ISC_R_SUCCESS)
			return (result);
		result = tresult;
	}
	if (ctx->done != NULL)
		(ctx->done)(ctx->done_arg, result);

 cleanup:
	if (ctx != NULL)
		dns_loadctx_detach(&ctx);
	return (result);
}

isc_result_t
dns_master_loadstream(FILE *stream, dns_name_t *top, dns_name_t *origin,
		      dns_rdataclass_t zclass, isc_boolean_t age_ttl,
		      dns_rdatacallbacks_t *callbacks, isc_mem_t *mctx)
{
	isc_result_t result;
	dns_loadctx_t *ctx = NULL;

	REQUIRE(stream != NULL);

	result = loadctx_create(mctx, age_ttl, top, zclass, origin,
				callbacks, NULL, NULL, NULL, &ctx);
	if (result != ISC_R_SUCCESS)
		goto cleanup;

	result = isc_lex_openstream(ctx->lex, stream);
	if (result != ISC_R_SUCCESS)
		goto cleanup;

	result = load(&ctx);
	INSIST(result != DNS_R_CONTINUE);

 cleanup:
	if (ctx != NULL)
		dns_loadctx_detach(&ctx);
	return (result);
}

isc_result_t
dns_master_loadstreaminc(FILE *stream, dns_name_t *top, dns_name_t *origin,
			 dns_rdataclass_t zclass, isc_boolean_t age_ttl,
			 dns_rdatacallbacks_t *callbacks, isc_task_t *task,
			 dns_loaddonefunc_t done, void *done_arg,
			 isc_mem_t *mctx)
{
	isc_result_t result;
	isc_result_t tresult;
	dns_loadctx_t *ctx = NULL;

	REQUIRE(stream != NULL);

	result = loadctx_create(mctx, age_ttl, top, zclass, origin,
				callbacks, task, done, done_arg, &ctx);
	if (result != ISC_R_SUCCESS)
		goto cleanup;

	result = isc_lex_openstream(ctx->lex, stream);
	if (result != ISC_R_SUCCESS)
		goto cleanup;

	result = load(&ctx);
	if (result == DNS_R_CONTINUE) {
		tresult = task_send(ctx);
		if (tresult == ISC_R_SUCCESS)
			return (result);
		result = tresult;
	}
	if (ctx->done != NULL)
		(ctx->done)(ctx->done_arg, result);

 cleanup:
	if (ctx != NULL)
		dns_loadctx_detach(&ctx);
	return (result);
}

isc_result_t
dns_master_loadbuffer(isc_buffer_t *buffer, dns_name_t *top,
		      dns_name_t *origin, dns_rdataclass_t zclass,
		      isc_boolean_t age_ttl,
		      dns_rdatacallbacks_t *callbacks, isc_mem_t *mctx)
{
	isc_result_t result;
	dns_loadctx_t *ctx = NULL;

	REQUIRE(buffer != NULL);

	result = loadctx_create(mctx, age_ttl, top, zclass, origin,
				callbacks, NULL, NULL, NULL, &ctx);
	if (result != ISC_R_SUCCESS)
		return (result);

	result = isc_lex_openbuffer(ctx->lex, buffer);
	if (result != ISC_R_SUCCESS)
		goto cleanup;

	result = load(&ctx);
	INSIST(result != DNS_R_CONTINUE);

 cleanup:
	if (ctx != NULL)
		dns_loadctx_detach(&ctx);
	return (result);
}

isc_result_t
dns_master_loadbufferinc(isc_buffer_t *buffer, dns_name_t *top,
			 dns_name_t *origin, dns_rdataclass_t zclass,
			 isc_boolean_t age_ttl,
			 dns_rdatacallbacks_t *callbacks, isc_task_t *task,
			 dns_loaddonefunc_t done, void *done_arg,
			 isc_mem_t *mctx)
{
	isc_result_t result;
	isc_result_t tresult;
	dns_loadctx_t *ctx = NULL;

	REQUIRE(buffer != NULL);

	result = loadctx_create(mctx, age_ttl, top, zclass, origin,
				callbacks, task, done, done_arg, &ctx);
	if (result != ISC_R_SUCCESS)
		return (result);

	result = isc_lex_openbuffer(ctx->lex, buffer);
	if (result != ISC_R_SUCCESS)
		goto cleanup;

	result = load(&ctx);
	if (result == DNS_R_CONTINUE) {
		tresult = task_send(ctx);
		if (tresult == ISC_R_SUCCESS)
			return (result);
		result = tresult;
	}
	if (ctx->done != NULL)
		(ctx->done)(ctx->done_arg, result);

 cleanup:
	if (ctx != NULL)
		dns_loadctx_detach(&ctx);
	return (result);
}

/*
 * Grow the slab of dns_rdatalist_t structures.
 * Re-link glue and current list.
 */
static dns_rdatalist_t *
grow_rdatalist(int new_len, dns_rdatalist_t *old, int old_len,
	       rdatalist_head_t *current, rdatalist_head_t *glue,
	       isc_mem_t *mctx)
{
	dns_rdatalist_t *new;
	int rdlcount = 0;
	ISC_LIST(dns_rdatalist_t) save;
	dns_rdatalist_t *this;

	new = isc_mem_get(mctx, new_len * sizeof *new);
	if (new == NULL)
		return (NULL);

	ISC_LIST_INIT(save);
	this = ISC_LIST_HEAD(*current);
	while ((this = ISC_LIST_HEAD(*current)) != NULL) {
		ISC_LIST_UNLINK(*current, this, link);
		ISC_LIST_APPEND(save, this, link);
	}
	while ((this = ISC_LIST_HEAD(save)) != NULL) {
		ISC_LIST_UNLINK(save, this, link);
		new[rdlcount] = *this;
		ISC_LIST_APPEND(*current, &new[rdlcount], link);
		rdlcount++;
	}

	ISC_LIST_INIT(save);
	this = ISC_LIST_HEAD(*glue);
	while ((this = ISC_LIST_HEAD(*glue)) != NULL) {
		ISC_LIST_UNLINK(*glue, this, link);
		ISC_LIST_APPEND(save, this, link);
	}
	while ((this = ISC_LIST_HEAD(save)) != NULL) {
		ISC_LIST_UNLINK(save, this, link);
		new[rdlcount] = *this;
		ISC_LIST_APPEND(*glue, &new[rdlcount], link);
		rdlcount++;
	}

	INSIST(rdlcount == old_len);
	if (old != NULL)
		isc_mem_put(mctx, old, old_len * sizeof *old);
	return (new);
}

/*
 * Grow the slab of rdata structs.
 * Re-link the current and glue chains.
 */
static dns_rdata_t *
grow_rdata(int new_len, dns_rdata_t *old, int old_len,
	   rdatalist_head_t *current, rdatalist_head_t *glue,
	   isc_mem_t *mctx)
{
	dns_rdata_t *new;
	int rdcount = 0;
	ISC_LIST(dns_rdata_t) save;
	dns_rdatalist_t *this;
	dns_rdata_t *rdata;

	new = isc_mem_get(mctx, new_len * sizeof *new);
	if (new == NULL)
		return (NULL);
	memset(new, 0, new_len * sizeof *new);

	/*
	 * Copy current relinking.
	 */
	this = ISC_LIST_HEAD(*current);
	while (this != NULL) {
		ISC_LIST_INIT(save);
		while ((rdata = ISC_LIST_HEAD(this->rdata)) != NULL) {
			ISC_LIST_UNLINK(this->rdata, rdata, link);
			ISC_LIST_APPEND(save, rdata, link);
		}
		while ((rdata = ISC_LIST_HEAD(save)) != NULL) {
			ISC_LIST_UNLINK(save, rdata, link);
			new[rdcount] = *rdata;
			ISC_LIST_APPEND(this->rdata, &new[rdcount], link);
			rdcount++;
		}
		this = ISC_LIST_NEXT(this, link);
	}

	/*
	 * Copy glue relinking.
	 */
	this = ISC_LIST_HEAD(*glue);
	while (this != NULL) {
		ISC_LIST_INIT(save);
		while ((rdata = ISC_LIST_HEAD(this->rdata)) != NULL) {
			ISC_LIST_UNLINK(this->rdata, rdata, link);
			ISC_LIST_APPEND(save, rdata, link);
		}
		while ((rdata = ISC_LIST_HEAD(save)) != NULL) {
			ISC_LIST_UNLINK(save, rdata, link);
			new[rdcount] = *rdata;
			ISC_LIST_APPEND(this->rdata, &new[rdcount], link);
			rdcount++;
		}
		this = ISC_LIST_NEXT(this, link);
	}
	INSIST(rdcount == old_len);
	if (old != NULL)
		isc_mem_put(mctx, old, old_len * sizeof *old);
	return (new);
}

/*
 * Convert each element from a rdatalist_t to rdataset then call commit.
 * Unlink each element as we go.
 */

static isc_result_t
commit(dns_rdatacallbacks_t *callbacks, isc_lex_t *lex,
       rdatalist_head_t *head, dns_name_t *owner, dns_name_t *top)
{
	dns_rdatalist_t *this;
	dns_rdataset_t dataset;
	isc_result_t result;
	isc_boolean_t ignore = ISC_FALSE;

	this = ISC_LIST_HEAD(*head);
	if (this == NULL)
		return (ISC_R_SUCCESS);
	if (!dns_name_issubdomain(owner, top)) {
		/*
		 * Ignore out-of-zone data.
		 */
		(callbacks->warn)(callbacks,
				  "%s: %s:%lu: "
				  "ignoring out-of-zone data",
				  "dns_master_load",
				  isc_lex_getsourcename(lex),
				  isc_lex_getsourceline(lex));
		ignore = ISC_TRUE;
	}
	do {
		if (!ignore) {
			dns_rdataset_init(&dataset);
			dns_rdatalist_tordataset(this, &dataset);
			dataset.trust = dns_trust_ultimate;
			result = ((*callbacks->add)(callbacks->add_private,
						    owner,
						    &dataset));
			if (result != ISC_R_SUCCESS)
				return (result);
		}
		ISC_LIST_UNLINK(*head, this, link);
		this = ISC_LIST_HEAD(*head);
	} while (this != NULL);
	return (ISC_R_SUCCESS);
}

/*
 * Returns ISC_TRUE if one of the NS rdata's contains 'owner'.
 */

static isc_boolean_t
is_glue(rdatalist_head_t *head, dns_name_t *owner) {
	dns_rdatalist_t *this;
	dns_rdata_t *rdata;
	isc_region_t region;
	dns_name_t name;

	/*
	 * Find NS rrset.
	 */
	this = ISC_LIST_HEAD(*head);
	while (this != NULL) {
		if (this->type == dns_rdatatype_ns)
			break;
		this = ISC_LIST_NEXT(this, link);
	}
	if (this == NULL)
		return (ISC_FALSE);

	rdata = ISC_LIST_HEAD(this->rdata);
	while (rdata != NULL) {
		dns_name_init(&name, NULL);
		dns_rdata_toregion(rdata, &region);
		dns_name_fromregion(&name, &region);
		if (dns_name_compare(&name, owner) == 0)
			return (ISC_TRUE);
		rdata = ISC_LIST_NEXT(rdata, link);
	}
	return (ISC_FALSE);
}

static void
load_quantum(isc_task_t *task, isc_event_t *event) {
	isc_result_t result;
	dns_loadctx_t *ctx;

	REQUIRE(event != NULL);
	ctx = event->ev_arg;
	REQUIRE(DNS_LCTX_VALID(ctx));

	if (ctx->canceled)
		result = ISC_R_CANCELED;
	else
		result = load(&ctx);
	if (result == DNS_R_CONTINUE) {
		isc_task_send(task, &event);
	} else if (result == ISC_R_SUCCESS && ctx->parent) {
		/* Pop ctx and continue. */
		event->ev_arg = ctx->parent;
		ctx->parent = NULL;
		dns_loadctx_detach(&ctx);
		isc_task_send(task, &event);
	} else {
		if (ctx->rate_limited)
			loadmgr_done(ctx, result);
		else
			(ctx->done)(ctx->done_arg, result);
		isc_event_free(&event);
		dns_loadctx_detach(&ctx);
	}
}

static isc_result_t
task_send(dns_loadctx_t *ctx) {
	isc_event_t *event;

	event = isc_event_allocate(ctx->mctx, NULL,
				   DNS_EVENT_MASTERQUANTUM,
				   load_quantum, ctx, sizeof(*event));
	if (event == NULL)
		return (ISC_R_NOMEMORY);
	isc_task_send(ctx->task, &event);
	return (ISC_R_SUCCESS);
}

/*
 * DNS load manager.
 */

isc_result_t
dns_loadmgr_create(isc_mem_t *mctx, dns_loadmgr_t **mgrp) {
	dns_loadmgr_t *mgr;
	isc_result_t result;

	REQUIRE(mgrp != NULL && *mgrp == NULL);

	mgr = isc_mem_get(mctx, sizeof(*mgr));
	if (mgr == NULL)
		return (ISC_R_NOMEMORY);
	result = isc_mutex_init(&mgr->lock);
	if (result != ISC_R_SUCCESS) {
		isc_mem_put(mctx, mgr, sizeof(*mgr));
		return (result);
	}
	mgr->erefs = 1;
	mgr->irefs = 0;
	mgr->limit = 0;
	mgr->active = 0;
	mgr->mctx = NULL;
	isc_mem_attach(mctx, &mgr->mctx);
	ISC_LIST_INIT(mgr->list);
	mgr->magic = DNS_LMGR_MAGIC;
	*mgrp = mgr;
	return (ISC_R_SUCCESS);
}

void
dns_loadmgr_setlimit(dns_loadmgr_t *mgr, isc_uint32_t limit) {

	REQUIRE(DNS_LMGR_VALID(mgr));

	mgr->limit = limit;
}

isc_uint32_t
dns_loadmgr_getlimit(dns_loadmgr_t *mgr) {

	REQUIRE(DNS_LMGR_VALID(mgr));

	return(mgr->limit);
}

void
dns_loadmgr_cancel(dns_loadmgr_t *mgr) {

	REQUIRE(DNS_LMGR_VALID(mgr));

	LOCK(&mgr->lock);
	loadmgr_cancel(mgr);
	UNLOCK(&mgr->lock);
}

static void
loadmgr_cancel(dns_loadmgr_t *mgr) {
	dns_loadctx_t *ctx;
	isc_event_t *event;

	for (ctx = ISC_LIST_HEAD(mgr->list); ctx != NULL; ) {
		ISC_LIST_UNLINK(mgr->list, ctx, link);
		event = &ctx->event;
		event->ev_attributes |= ISC_EVENTATTR_CANCELED;
		isc_task_send(ctx->task, &event);
	}
}

void
dns_loadctx_cancel(dns_loadctx_t *ctx) {
	isc_event_t *event;

	REQUIRE(DNS_LCTX_VALID(ctx));

	LOCK(&ctx->lock);
	ctx->canceled = ISC_TRUE;
	/*
	 * If we are queued to be run dequeue.
	 */
	if (ctx->loadmgr != NULL && ISC_LINK_LINKED(ctx, link)) {
		LOCK(&ctx->loadmgr->lock);
		ISC_LIST_UNLINK(ctx->loadmgr->list, ctx, link);
		UNLOCK(&ctx->loadmgr->lock);
		event = &ctx->event;
		event->ev_attributes |= ISC_EVENTATTR_CANCELED;
		isc_task_send(ctx->task, &event);
	}
	UNLOCK(&ctx->lock);
}


void
dns_loadmgr_attach(dns_loadmgr_t *source, dns_loadmgr_t **target) {

	REQUIRE(DNS_LMGR_VALID(source));
	REQUIRE(target != NULL && *target == NULL);

	LOCK(&source->lock);
	INSIST(source->erefs != 0);
	source->erefs++;
	INSIST(source->erefs != 0);	/* Overflow? */
	UNLOCK(&source->lock);

	*target = source;
}

void
dns_loadmgr_detach(dns_loadmgr_t **mgrp) {
	dns_loadmgr_t *mgr;
	isc_boolean_t destroy = ISC_FALSE;

	REQUIRE(mgrp != NULL);
	mgr = *mgrp;
	REQUIRE(DNS_LMGR_VALID(mgr));

	mgrp = NULL;

	LOCK(&mgr->lock);
	INSIST(mgr->erefs != 0);
	mgr->erefs--;
	if (mgr->erefs == 0) {
		if (mgr->irefs == 0)
			destroy = ISC_TRUE;
		else
			loadmgr_cancel(mgr);
	}
	UNLOCK(&mgr->lock);
	if (destroy)
		loadmgr_destroy(mgr);
}

static void
loadmgr_iattach(dns_loadmgr_t *source, dns_loadmgr_t **target) {

	REQUIRE(DNS_LMGR_VALID(source));
	REQUIRE(target != NULL && *target == NULL);

	LOCK(&source->lock);
	source->irefs++;
	INSIST(source->irefs != 0);	/* Overflow? */
	UNLOCK(&source->lock);

	*target = source;
}

static void
loadmgr_idetach(dns_loadmgr_t **mgrp) {
	dns_loadmgr_t *mgr;
	isc_boolean_t destroy = ISC_FALSE;

	REQUIRE(mgrp != NULL);
	mgr = *mgrp;
	REQUIRE(DNS_LMGR_VALID(mgr));

	mgrp = NULL;

	LOCK(&mgr->lock);
	INSIST(mgr->irefs != 0);
	mgr->irefs--;
	if (mgr->erefs == 0 && mgr->irefs == 0)
		destroy = ISC_TRUE;
	UNLOCK(&mgr->lock);
	if (destroy)
		loadmgr_destroy(mgr);
}

static void
loadmgr_destroy(dns_loadmgr_t *mgr) {

	INSIST(ISC_LIST_EMPTY(mgr->list));

	mgr->magic = 0;
	DESTROYLOCK(&mgr->lock);
	isc_mem_putanddetach(&mgr->mctx, mgr, sizeof(*mgr));
}