Adding upstream version 1:9.18.19.upstream/1%9.18.19

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 2094 insertions, 0 deletions

diff --git a/lib/dns/masterdump.c b/lib/dns/masterdump.c
new file mode 100644
index 0000000..4946d0d
--- /dev/null
+++ b/lib/dns/masterdump.c
@@ -0,0 +1,2094 @@
+/*
+ * Copyright (C) Internet Systems Consortium, Inc. ("ISC")
+ *
+ * SPDX-License-Identifier: MPL-2.0
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, you can obtain one at https://mozilla.org/MPL/2.0/.
+ *
+ * See the COPYRIGHT file distributed with this work for additional
+ * information regarding copyright ownership.
+ */
+
+/*! \file */
+
+#include <inttypes.h>
+#include <stdbool.h>
+#include <stdlib.h>
+
+#include <isc/atomic.h>
+#include <isc/buffer.h>
+#include <isc/event.h>
+#include <isc/file.h>
+#include <isc/magic.h>
+#include <isc/mem.h>
+#include <isc/print.h>
+#include <isc/refcount.h>
+#include <isc/result.h>
+#include <isc/stdio.h>
+#include <isc/string.h>
+#include <isc/task.h>
+#include <isc/time.h>
+#include <isc/types.h>
+#include <isc/util.h>
+
+#include <dns/db.h>
+#include <dns/dbiterator.h>
+#include <dns/events.h>
+#include <dns/fixedname.h>
+#include <dns/log.h>
+#include <dns/master.h>
+#include <dns/masterdump.h>
+#include <dns/ncache.h>
+#include <dns/rdata.h>
+#include <dns/rdataclass.h>
+#include <dns/rdataset.h>
+#include <dns/rdatasetiter.h>
+#include <dns/rdatatype.h>
+#include <dns/time.h>
+#include <dns/ttl.h>
+
+#define DNS_DCTX_MAGIC	  ISC_MAGIC('D', 'c', 't', 'x')
+#define DNS_DCTX_VALID(d) ISC_MAGIC_VALID(d, DNS_DCTX_MAGIC)
+
+#define RETERR(x)                        \
+	do {                             \
+		isc_result_t _r = (x);   \
+		if (_r != ISC_R_SUCCESS) \
+			return ((_r));   \
+	} while (0)
+
+#define CHECK(x)                          \
+	do {                              \
+		if ((x) != ISC_R_SUCCESS) \
+			goto cleanup;     \
+	} while (0)
+
+struct dns_master_style {
+	dns_masterstyle_flags_t flags; /* DNS_STYLEFLAG_* */
+	unsigned int ttl_column;
+	unsigned int class_column;
+	unsigned int type_column;
+	unsigned int rdata_column;
+	unsigned int line_length;
+	unsigned int tab_width;
+	unsigned int split_width;
+};
+
+/*%
+ * The maximum length of the newline+indentation that is output
+ * when inserting a line break in an RR.  This effectively puts an
+ * upper limits on the value of "rdata_column", because if it is
+ * very large, the tabs and spaces needed to reach it will not fit.
+ */
+#define DNS_TOTEXT_LINEBREAK_MAXLEN 100
+
+/*% Does the rdataset 'r' contain a stale answer? */
+#define STALE(r) (((r)->attributes & DNS_RDATASETATTR_STALE) != 0)
+/*% Does the rdataset 'r' contain an expired answer? */
+#define ANCIENT(r) (((r)->attributes & DNS_RDATASETATTR_ANCIENT) != 0)
+
+/*%
+ * Context structure for a masterfile dump in progress.
+ */
+typedef struct dns_totext_ctx {
+	dns_master_style_t style;
+	bool class_printed;
+	char *linebreak;
+	char linebreak_buf[DNS_TOTEXT_LINEBREAK_MAXLEN];
+	dns_name_t *origin;
+	dns_name_t *neworigin;
+	dns_fixedname_t origin_fixname;
+	uint32_t current_ttl;
+	bool current_ttl_valid;
+	dns_ttl_t serve_stale_ttl;
+	dns_indent_t indent;
+} dns_totext_ctx_t;
+
+const dns_master_style_t dns_master_style_keyzone = {
+	DNS_STYLEFLAG_OMIT_OWNER | DNS_STYLEFLAG_OMIT_CLASS |
+		DNS_STYLEFLAG_REL_OWNER | DNS_STYLEFLAG_REL_DATA |
+		DNS_STYLEFLAG_OMIT_TTL | DNS_STYLEFLAG_TTL |
+		DNS_STYLEFLAG_COMMENT | DNS_STYLEFLAG_RRCOMMENT |
+		DNS_STYLEFLAG_MULTILINE | DNS_STYLEFLAG_KEYDATA,
+	24,
+	24,
+	24,
+	32,
+	80,
+	8,
+	UINT_MAX
+};
+
+const dns_master_style_t dns_master_style_default = {
+	DNS_STYLEFLAG_OMIT_OWNER | DNS_STYLEFLAG_OMIT_CLASS |
+		DNS_STYLEFLAG_REL_OWNER | DNS_STYLEFLAG_REL_DATA |
+		DNS_STYLEFLAG_OMIT_TTL | DNS_STYLEFLAG_TTL |
+		DNS_STYLEFLAG_COMMENT | DNS_STYLEFLAG_RRCOMMENT |
+		DNS_STYLEFLAG_MULTILINE,
+	24,
+	24,
+	24,
+	32,
+	80,
+	8,
+	UINT_MAX
+};
+
+const dns_master_style_t dns_master_style_full = {
+	DNS_STYLEFLAG_COMMENT | DNS_STYLEFLAG_RESIGN,
+	46,
+	46,
+	46,
+	64,
+	120,
+	8,
+	UINT_MAX
+};
+
+const dns_master_style_t dns_master_style_explicitttl = {
+	DNS_STYLEFLAG_OMIT_OWNER | DNS_STYLEFLAG_OMIT_CLASS |
+		DNS_STYLEFLAG_REL_OWNER | DNS_STYLEFLAG_REL_DATA |
+		DNS_STYLEFLAG_COMMENT | DNS_STYLEFLAG_RRCOMMENT |
+		DNS_STYLEFLAG_MULTILINE,
+	24,
+	32,
+	32,
+	40,
+	80,
+	8,
+	UINT_MAX
+};
+
+const dns_master_style_t dns_master_style_cache = {
+	DNS_STYLEFLAG_OMIT_OWNER | DNS_STYLEFLAG_OMIT_CLASS |
+		DNS_STYLEFLAG_MULTILINE | DNS_STYLEFLAG_RRCOMMENT |
+		DNS_STYLEFLAG_TRUST | DNS_STYLEFLAG_NCACHE,
+	24,
+	32,
+	32,
+	40,
+	80,
+	8,
+	UINT_MAX
+};
+
+const dns_master_style_t dns_master_style_cache_with_expired = {
+	DNS_STYLEFLAG_OMIT_OWNER | DNS_STYLEFLAG_OMIT_CLASS |
+		DNS_STYLEFLAG_MULTILINE | DNS_STYLEFLAG_RRCOMMENT |
+		DNS_STYLEFLAG_TRUST | DNS_STYLEFLAG_NCACHE |
+		DNS_STYLEFLAG_EXPIRED,
+	24,
+	32,
+	32,
+	40,
+	80,
+	8,
+	UINT_MAX
+};
+
+const dns_master_style_t dns_master_style_simple = { 0,	 24, 32, 32,
+						     40, 80, 8,	 UINT_MAX };
+
+/*%
+ * A style suitable for dns_rdataset_totext().
+ */
+const dns_master_style_t dns_master_style_debug = {
+	DNS_STYLEFLAG_REL_OWNER, 24, 32, 40, 48, 80, 8, UINT_MAX
+};
+
+/*%
+ * Similar, but indented (i.e., prepended with indentctx.string).
+ */
+const dns_master_style_t dns_master_style_indent = {
+	DNS_STYLEFLAG_REL_OWNER | DNS_STYLEFLAG_INDENT,
+	24,
+	32,
+	40,
+	48,
+	80,
+	8,
+	UINT_MAX
+};
+
+/*%
+ * Similar, but with each line commented out.
+ */
+const dns_master_style_t dns_master_style_comment = {
+	DNS_STYLEFLAG_REL_OWNER | DNS_STYLEFLAG_MULTILINE |
+		DNS_STYLEFLAG_RRCOMMENT | DNS_STYLEFLAG_COMMENTDATA,
+	24,
+	32,
+	40,
+	48,
+	80,
+	8,
+	UINT_MAX
+};
+
+/*%
+ * YAML style
+ */
+const dns_master_style_t dns_master_style_yaml = {
+	DNS_STYLEFLAG_YAML | DNS_STYLEFLAG_REL_OWNER | DNS_STYLEFLAG_INDENT,
+	24,
+	32,
+	40,
+	48,
+	80,
+	8,
+	UINT_MAX
+};
+
+#define N_SPACES 10
+static char spaces[N_SPACES + 1] = "          ";
+
+#define N_TABS 10
+static char tabs[N_TABS + 1] = "\t\t\t\t\t\t\t\t\t\t";
+
+struct dns_dumpctx {
+	unsigned int magic;
+	isc_mem_t *mctx;
+	isc_mutex_t lock;
+	isc_refcount_t references;
+	atomic_bool canceled;
+	bool do_date;
+	isc_stdtime_t now;
+	FILE *f;
+	dns_db_t *db;
+	dns_dbversion_t *version;
+	dns_dbiterator_t *dbiter;
+	dns_totext_ctx_t tctx;
+	isc_task_t *task;
+	dns_dumpdonefunc_t done;
+	void *done_arg;
+	/* dns_master_dumpasync() */
+	isc_result_t result;
+	char *file;
+	char *tmpfile;
+	dns_masterformat_t format;
+	dns_masterrawheader_t header;
+	isc_result_t (*dumpsets)(isc_mem_t *mctx, const dns_name_t *name,
+				 dns_rdatasetiter_t *rdsiter,
+				 dns_totext_ctx_t *ctx, isc_buffer_t *buffer,
+				 FILE *f);
+};
+
+#define NXDOMAIN(x) (((x)->attributes & DNS_RDATASETATTR_NXDOMAIN) != 0)
+
+static const dns_indent_t default_indent = { "\t", 1 };
+static const dns_indent_t default_yamlindent = { "  ", 1 };
+
+/*%
+ * Output tabs and spaces to go from column '*current' to
+ * column 'to', and update '*current' to reflect the new
+ * current column.
+ */
+static isc_result_t
+indent(unsigned int *current, unsigned int to, int tabwidth,
+       isc_buffer_t *target) {
+	isc_region_t r;
+	unsigned char *p;
+	unsigned int from;
+	int ntabs, nspaces, t;
+
+	from = *current;
+
+	if (to < from + 1) {
+		to = from + 1;
+	}
+
+	ntabs = to / tabwidth - from / tabwidth;
+	if (ntabs < 0) {
+		ntabs = 0;
+	}
+
+	if (ntabs > 0) {
+		isc_buffer_availableregion(target, &r);
+		if (r.length < (unsigned)ntabs) {
+			return (ISC_R_NOSPACE);
+		}
+		p = r.base;
+
+		t = ntabs;
+		while (t) {
+			int n = t;
+			if (n > N_TABS) {
+				n = N_TABS;
+			}
+			memmove(p, tabs, n);
+			p += n;
+			t -= n;
+		}
+		isc_buffer_add(target, ntabs);
+		from = (to / tabwidth) * tabwidth;
+	}
+
+	nspaces = to - from;
+	INSIST(nspaces >= 0);
+
+	isc_buffer_availableregion(target, &r);
+	if (r.length < (unsigned)nspaces) {
+		return (ISC_R_NOSPACE);
+	}
+	p = r.base;
+
+	t = nspaces;
+	while (t) {
+		int n = t;
+		if (n > N_SPACES) {
+			n = N_SPACES;
+		}
+		memmove(p, spaces, n);
+		p += n;
+		t -= n;
+	}
+	isc_buffer_add(target, nspaces);
+
+	*current = to;
+	return (ISC_R_SUCCESS);
+}
+
+static isc_result_t
+totext_ctx_init(const dns_master_style_t *style, const dns_indent_t *indentctx,
+		dns_totext_ctx_t *ctx) {
+	isc_result_t result;
+
+	REQUIRE(style->tab_width != 0);
+
+	if (indentctx == NULL) {
+		if ((style->flags & DNS_STYLEFLAG_YAML) != 0) {
+			indentctx = &default_yamlindent;
+		} else {
+			indentctx = &default_indent;
+		}
+	}
+
+	ctx->style = *style;
+	ctx->class_printed = false;
+
+	dns_fixedname_init(&ctx->origin_fixname);
+
+	/*
+	 * Set up the line break string if needed.
+	 */
+	if ((ctx->style.flags & DNS_STYLEFLAG_MULTILINE) != 0) {
+		isc_buffer_t buf;
+		isc_region_t r;
+		unsigned int col = 0;
+
+		isc_buffer_init(&buf, ctx->linebreak_buf,
+				sizeof(ctx->linebreak_buf));
+
+		isc_buffer_availableregion(&buf, &r);
+		if (r.length < 1) {
+			return (DNS_R_TEXTTOOLONG);
+		}
+		r.base[0] = '\n';
+		isc_buffer_add(&buf, 1);
+
+		if ((ctx->style.flags & DNS_STYLEFLAG_INDENT) != 0 ||
+		    (ctx->style.flags & DNS_STYLEFLAG_YAML) != 0)
+		{
+			unsigned int i, len = strlen(indentctx->string);
+			for (i = 0; i < indentctx->count; i++) {
+				if (isc_buffer_availablelength(&buf) < len) {
+					return (DNS_R_TEXTTOOLONG);
+				}
+				isc_buffer_putstr(&buf, indentctx->string);
+			}
+		}
+
+		if ((ctx->style.flags & DNS_STYLEFLAG_COMMENTDATA) != 0) {
+			isc_buffer_availableregion(&buf, &r);
+			if (r.length < 1) {
+				return (DNS_R_TEXTTOOLONG);
+			}
+			r.base[0] = ';';
+			isc_buffer_add(&buf, 1);
+		}
+
+		result = indent(&col, ctx->style.rdata_column,
+				ctx->style.tab_width, &buf);
+		/*
+		 * Do not return ISC_R_NOSPACE if the line break string
+		 * buffer is too small, because that would just make
+		 * dump_rdataset() retry indefinitely with ever
+		 * bigger target buffers.  That's a different buffer,
+		 * so it won't help.  Use DNS_R_TEXTTOOLONG as a substitute.
+		 */
+		if (result == ISC_R_NOSPACE) {
+			return (DNS_R_TEXTTOOLONG);
+		}
+		if (result != ISC_R_SUCCESS) {
+			return (result);
+		}
+
+		isc_buffer_availableregion(&buf, &r);
+		if (r.length < 1) {
+			return (DNS_R_TEXTTOOLONG);
+		}
+		r.base[0] = '\0';
+		isc_buffer_add(&buf, 1);
+		ctx->linebreak = ctx->linebreak_buf;
+	} else {
+		ctx->linebreak = NULL;
+	}
+
+	ctx->origin = NULL;
+	ctx->neworigin = NULL;
+	ctx->current_ttl = 0;
+	ctx->current_ttl_valid = false;
+	ctx->serve_stale_ttl = 0;
+	ctx->indent = *indentctx;
+
+	return (ISC_R_SUCCESS);
+}
+
+#define INDENT_TO(col)                                                        \
+	do {                                                                  \
+		if ((ctx->style.flags & DNS_STYLEFLAG_YAML) != 0) {           \
+			if ((result = str_totext(" ", target)) !=             \
+			    ISC_R_SUCCESS)                                    \
+				return ((result));                            \
+		} else if ((result = indent(&column, ctx->style.col,          \
+					    ctx->style.tab_width, target)) != \
+			   ISC_R_SUCCESS)                                     \
+			return ((result));                                    \
+	} while (0)
+
+static isc_result_t
+str_totext(const char *source, isc_buffer_t *target) {
+	unsigned int l;
+	isc_region_t region;
+
+	isc_buffer_availableregion(target, &region);
+	l = strlen(source);
+
+	if (l > region.length) {
+		return (ISC_R_NOSPACE);
+	}
+
+	memmove(region.base, source, l);
+	isc_buffer_add(target, l);
+	return (ISC_R_SUCCESS);
+}
+
+static isc_result_t
+ncache_summary(dns_rdataset_t *rdataset, bool omit_final_dot,
+	       dns_totext_ctx_t *ctx, isc_buffer_t *target) {
+	isc_result_t result = ISC_R_SUCCESS;
+	dns_rdataset_t rds;
+	dns_name_t name;
+
+	dns_rdataset_init(&rds);
+	dns_name_init(&name, NULL);
+
+	do {
+		dns_ncache_current(rdataset, &name, &rds);
+		for (result = dns_rdataset_first(&rds); result == ISC_R_SUCCESS;
+		     result = dns_rdataset_next(&rds))
+		{
+			if ((ctx->style.flags & DNS_STYLEFLAG_INDENT) != 0 ||
+			    (ctx->style.flags & DNS_STYLEFLAG_YAML) != 0)
+			{
+				unsigned int i;
+				for (i = 0; i < ctx->indent.count; i++) {
+					CHECK(str_totext(ctx->indent.string,
+							 target));
+				}
+			}
+
+			if ((ctx->style.flags & DNS_STYLEFLAG_YAML) != 0) {
+				CHECK(str_totext("- ", target));
+			} else {
+				CHECK(str_totext("; ", target));
+			}
+
+			CHECK(dns_name_totext(&name, omit_final_dot, target));
+			CHECK(str_totext(" ", target));
+			CHECK(dns_rdatatype_totext(rds.type, target));
+			if (rds.type == dns_rdatatype_rrsig) {
+				CHECK(str_totext(" ", target));
+				CHECK(dns_rdatatype_totext(rds.covers, target));
+				CHECK(str_totext(" ...\n", target));
+			} else {
+				dns_rdata_t rdata = DNS_RDATA_INIT;
+				dns_rdataset_current(&rds, &rdata);
+				CHECK(str_totext(" ", target));
+				CHECK(dns_rdata_tofmttext(&rdata, dns_rootname,
+							  0, 0, 0, " ",
+							  target));
+				CHECK(str_totext("\n", target));
+			}
+		}
+		dns_rdataset_disassociate(&rds);
+		result = dns_rdataset_next(rdataset);
+	} while (result == ISC_R_SUCCESS);
+
+	if (result == ISC_R_NOMORE) {
+		result = ISC_R_SUCCESS;
+	}
+cleanup:
+	if (dns_rdataset_isassociated(&rds)) {
+		dns_rdataset_disassociate(&rds);
+	}
+
+	return (result);
+}
+
+/*
+ * Convert 'rdataset' to master file text format according to 'ctx',
+ * storing the result in 'target'.  If 'owner_name' is NULL, it
+ * is omitted; otherwise 'owner_name' must be valid and have at least
+ * one label.
+ */
+
+static isc_result_t
+rdataset_totext(dns_rdataset_t *rdataset, const dns_name_t *owner_name,
+		dns_totext_ctx_t *ctx, bool omit_final_dot,
+		isc_buffer_t *target) {
+	isc_result_t result;
+	unsigned int column;
+	bool first = true;
+	uint32_t current_ttl;
+	bool current_ttl_valid;
+	dns_rdatatype_t type;
+	unsigned int type_start;
+	dns_fixedname_t fixed;
+	dns_name_t *name = NULL;
+	unsigned int i;
+
+	REQUIRE(DNS_RDATASET_VALID(rdataset));
+
+	rdataset->attributes |= DNS_RDATASETATTR_LOADORDER;
+	result = dns_rdataset_first(rdataset);
+
+	current_ttl = ctx->current_ttl;
+	current_ttl_valid = ctx->current_ttl_valid;
+
+	if (owner_name != NULL) {
+		name = dns_fixedname_initname(&fixed);
+		dns_name_copy(owner_name, name);
+		dns_rdataset_getownercase(rdataset, name);
+	}
+
+	while (result == ISC_R_SUCCESS) {
+		column = 0;
+
+		/*
+		 * Indent?
+		 */
+		if ((ctx->style.flags & DNS_STYLEFLAG_INDENT) != 0 ||
+		    (ctx->style.flags & DNS_STYLEFLAG_YAML) != 0)
+		{
+			for (i = 0; i < ctx->indent.count; i++) {
+				RETERR(str_totext(ctx->indent.string, target));
+			}
+		}
+
+		/*
+		 * YAML or comment prefix?
+		 */
+		if ((ctx->style.flags & DNS_STYLEFLAG_YAML) != 0) {
+			RETERR(str_totext("- ", target));
+		} else if ((ctx->style.flags & DNS_STYLEFLAG_COMMENTDATA) != 0)
+		{
+			RETERR(str_totext(";", target));
+		}
+
+		/*
+		 * Owner name.
+		 */
+		if (name != NULL &&
+		    !((ctx->style.flags & DNS_STYLEFLAG_OMIT_OWNER) != 0 &&
+		      !first))
+		{
+			unsigned int name_start = target->used;
+			RETERR(dns_name_totext(name, omit_final_dot, target));
+			column += target->used - name_start;
+		}
+
+		/*
+		 * TTL.
+		 */
+		if ((ctx->style.flags & DNS_STYLEFLAG_NO_TTL) == 0 &&
+		    !((ctx->style.flags & DNS_STYLEFLAG_OMIT_TTL) != 0 &&
+		      current_ttl_valid && rdataset->ttl == current_ttl))
+		{
+			char ttlbuf[64];
+			isc_region_t r;
+			unsigned int length;
+
+			INDENT_TO(ttl_column);
+			if ((ctx->style.flags & DNS_STYLEFLAG_TTL_UNITS) != 0) {
+				length = target->used;
+				result = dns_ttl_totext(rdataset->ttl, false,
+							false, target);
+				if (result != ISC_R_SUCCESS) {
+					return (result);
+				}
+				column += target->used - length;
+			} else {
+				length = snprintf(ttlbuf, sizeof(ttlbuf), "%u",
+						  rdataset->ttl);
+				INSIST(length <= sizeof(ttlbuf));
+				isc_buffer_availableregion(target, &r);
+				if (r.length < length) {
+					return (ISC_R_NOSPACE);
+				}
+				memmove(r.base, ttlbuf, length);
+				isc_buffer_add(target, length);
+				column += length;
+			}
+
+			/*
+			 * If the $TTL directive is not in use, the TTL we
+			 * just printed becomes the default for subsequent RRs.
+			 */
+			if ((ctx->style.flags & DNS_STYLEFLAG_TTL) == 0) {
+				current_ttl = rdataset->ttl;
+				current_ttl_valid = true;
+			}
+		}
+
+		/*
+		 * Class.
+		 */
+		if ((ctx->style.flags & DNS_STYLEFLAG_NO_CLASS) == 0 &&
+		    ((ctx->style.flags & DNS_STYLEFLAG_OMIT_CLASS) == 0 ||
+		     !ctx->class_printed))
+		{
+			unsigned int class_start;
+			INDENT_TO(class_column);
+			class_start = target->used;
+			if ((ctx->style.flags & DNS_STYLEFLAG_UNKNOWNFORMAT) !=
+			    0)
+			{
+				result = dns_rdataclass_tounknowntext(
+					rdataset->rdclass, target);
+			} else {
+				result = dns_rdataclass_totext(
+					rdataset->rdclass, target);
+			}
+			if (result != ISC_R_SUCCESS) {
+				return (result);
+			}
+			column += (target->used - class_start);
+		}
+
+		/*
+		 * Type.
+		 */
+
+		if ((rdataset->attributes & DNS_RDATASETATTR_NEGATIVE) != 0) {
+			type = rdataset->covers;
+		} else {
+			type = rdataset->type;
+		}
+
+		INDENT_TO(type_column);
+		type_start = target->used;
+		if ((rdataset->attributes & DNS_RDATASETATTR_NEGATIVE) != 0) {
+			RETERR(str_totext("\\-", target));
+		}
+		switch (type) {
+		case dns_rdatatype_keydata:
+#define KEYDATA "KEYDATA"
+			if ((ctx->style.flags & DNS_STYLEFLAG_KEYDATA) != 0) {
+				if (isc_buffer_availablelength(target) <
+				    (sizeof(KEYDATA) - 1))
+				{
+					return (ISC_R_NOSPACE);
+				}
+				isc_buffer_putstr(target, KEYDATA);
+				break;
+			}
+			FALLTHROUGH;
+		default:
+			if ((ctx->style.flags & DNS_STYLEFLAG_UNKNOWNFORMAT) !=
+			    0)
+			{
+				result = dns_rdatatype_tounknowntext(type,
+								     target);
+			} else {
+				result = dns_rdatatype_totext(type, target);
+			}
+			if (result != ISC_R_SUCCESS) {
+				return (result);
+			}
+		}
+		column += (target->used - type_start);
+
+		/*
+		 * Rdata.
+		 */
+		INDENT_TO(rdata_column);
+		if ((rdataset->attributes & DNS_RDATASETATTR_NEGATIVE) != 0) {
+			if (NXDOMAIN(rdataset)) {
+				RETERR(str_totext(";-$NXDOMAIN\n", target));
+			} else {
+				RETERR(str_totext(";-$NXRRSET\n", target));
+			}
+			/*
+			 * Print a summary of the cached records which make
+			 * up the negative response.
+			 */
+			RETERR(ncache_summary(rdataset, omit_final_dot, ctx,
+					      target));
+			break;
+		} else {
+			dns_rdata_t rdata = DNS_RDATA_INIT;
+			isc_region_t r;
+
+			dns_rdataset_current(rdataset, &rdata);
+
+			RETERR(dns_rdata_tofmttext(
+				&rdata, ctx->origin, ctx->style.flags,
+				ctx->style.line_length -
+					ctx->style.rdata_column,
+				ctx->style.split_width, ctx->linebreak,
+				target));
+
+			isc_buffer_availableregion(target, &r);
+			if (r.length < 1) {
+				return (ISC_R_NOSPACE);
+			}
+			r.base[0] = '\n';
+			isc_buffer_add(target, 1);
+		}
+
+		first = false;
+		result = dns_rdataset_next(rdataset);
+	}
+
+	if (result != ISC_R_NOMORE) {
+		return (result);
+	}
+
+	/*
+	 * Update the ctx state to reflect what we just printed.
+	 * This is done last, only when we are sure we will return
+	 * success, because this function may be called multiple
+	 * times with increasing buffer sizes until it succeeds,
+	 * and failed attempts must not update the state prematurely.
+	 */
+	ctx->class_printed = true;
+	ctx->current_ttl = current_ttl;
+	ctx->current_ttl_valid = current_ttl_valid;
+
+	return (ISC_R_SUCCESS);
+}
+
+/*
+ * Print the name, type, and class of an empty rdataset,
+ * such as those used to represent the question section
+ * of a DNS message.
+ */
+static isc_result_t
+question_totext(dns_rdataset_t *rdataset, const dns_name_t *owner_name,
+		dns_totext_ctx_t *ctx, bool omit_final_dot,
+		isc_buffer_t *target) {
+	unsigned int column;
+	isc_result_t result;
+	isc_region_t r;
+
+	REQUIRE(DNS_RDATASET_VALID(rdataset));
+	result = dns_rdataset_first(rdataset);
+	REQUIRE(result == ISC_R_NOMORE);
+
+	column = 0;
+
+	/* Owner name */
+	{
+		unsigned int name_start = target->used;
+		RETERR(dns_name_totext(owner_name, omit_final_dot, target));
+		column += target->used - name_start;
+	}
+
+	/* Class */
+	{
+		unsigned int class_start;
+		INDENT_TO(class_column);
+		class_start = target->used;
+		if ((ctx->style.flags & DNS_STYLEFLAG_UNKNOWNFORMAT) != 0) {
+			result = dns_rdataclass_tounknowntext(rdataset->rdclass,
+							      target);
+		} else {
+			result = dns_rdataclass_totext(rdataset->rdclass,
+						       target);
+		}
+		if (result != ISC_R_SUCCESS) {
+			return (result);
+		}
+		column += (target->used - class_start);
+	}
+
+	/* Type */
+	{
+		unsigned int type_start;
+		INDENT_TO(type_column);
+		type_start = target->used;
+		if ((ctx->style.flags & DNS_STYLEFLAG_UNKNOWNFORMAT) != 0) {
+			result = dns_rdatatype_tounknowntext(rdataset->type,
+							     target);
+		} else {
+			result = dns_rdatatype_totext(rdataset->type, target);
+		}
+		if (result != ISC_R_SUCCESS) {
+			return (result);
+		}
+		column += (target->used - type_start);
+	}
+
+	isc_buffer_availableregion(target, &r);
+	if (r.length < 1) {
+		return (ISC_R_NOSPACE);
+	}
+	r.base[0] = '\n';
+	isc_buffer_add(target, 1);
+
+	return (ISC_R_SUCCESS);
+}
+
+isc_result_t
+dns_rdataset_totext(dns_rdataset_t *rdataset, const dns_name_t *owner_name,
+		    bool omit_final_dot, bool question, isc_buffer_t *target) {
+	dns_totext_ctx_t ctx;
+	isc_result_t result;
+	result = totext_ctx_init(&dns_master_style_debug, NULL, &ctx);
+	if (result != ISC_R_SUCCESS) {
+		UNEXPECTED_ERROR("could not set master file style");
+		return (ISC_R_UNEXPECTED);
+	}
+
+	/*
+	 * The caller might want to give us an empty owner
+	 * name (e.g. if they are outputting into a master
+	 * file and this rdataset has the same name as the
+	 * previous one.)
+	 */
+	if (dns_name_countlabels(owner_name) == 0) {
+		owner_name = NULL;
+	}
+
+	if (question) {
+		return (question_totext(rdataset, owner_name, &ctx,
+					omit_final_dot, target));
+	} else {
+		return (rdataset_totext(rdataset, owner_name, &ctx,
+					omit_final_dot, target));
+	}
+}
+
+isc_result_t
+dns_master_rdatasettotext(const dns_name_t *owner_name,
+			  dns_rdataset_t *rdataset,
+			  const dns_master_style_t *style, dns_indent_t *indent,
+			  isc_buffer_t *target) {
+	dns_totext_ctx_t ctx;
+	isc_result_t result;
+	result = totext_ctx_init(style, indent, &ctx);
+	if (result != ISC_R_SUCCESS) {
+		UNEXPECTED_ERROR("could not set master file style");
+		return (ISC_R_UNEXPECTED);
+	}
+
+	return (rdataset_totext(rdataset, owner_name, &ctx, false, target));
+}
+
+isc_result_t
+dns_master_questiontotext(const dns_name_t *owner_name,
+			  dns_rdataset_t *rdataset,
+			  const dns_master_style_t *style,
+			  isc_buffer_t *target) {
+	dns_totext_ctx_t ctx;
+	isc_result_t result;
+	result = totext_ctx_init(style, NULL, &ctx);
+	if (result != ISC_R_SUCCESS) {
+		UNEXPECTED_ERROR("could not set master file style");
+		return (ISC_R_UNEXPECTED);
+	}
+
+	return (question_totext(rdataset, owner_name, &ctx, false, target));
+}
+
+/*
+ * Print an rdataset.  'buffer' is a scratch buffer, which must have been
+ * dynamically allocated by the caller.  It must be large enough to
+ * hold the result from dns_ttl_totext().  If more than that is needed,
+ * the buffer will be grown automatically.
+ */
+
+static isc_result_t
+dump_rdataset(isc_mem_t *mctx, const dns_name_t *name, dns_rdataset_t *rdataset,
+	      dns_totext_ctx_t *ctx, isc_buffer_t *buffer, FILE *f) {
+	isc_region_t r;
+	isc_result_t result;
+
+	REQUIRE(buffer->length > 0);
+
+	/*
+	 * Output a $TTL directive if needed.
+	 */
+
+	if ((ctx->style.flags & DNS_STYLEFLAG_TTL) != 0) {
+		if (!ctx->current_ttl_valid ||
+		    ctx->current_ttl != rdataset->ttl)
+		{
+			if ((ctx->style.flags & DNS_STYLEFLAG_COMMENT) != 0) {
+				isc_buffer_clear(buffer);
+				result = dns_ttl_totext(rdataset->ttl, true,
+							true, buffer);
+				INSIST(result == ISC_R_SUCCESS);
+				isc_buffer_usedregion(buffer, &r);
+				fprintf(f, "$TTL %u\t; %.*s\n", rdataset->ttl,
+					(int)r.length, (char *)r.base);
+			} else {
+				fprintf(f, "$TTL %u\n", rdataset->ttl);
+			}
+			ctx->current_ttl = rdataset->ttl;
+			ctx->current_ttl_valid = true;
+		}
+	}
+
+	isc_buffer_clear(buffer);
+
+	/*
+	 * Generate the text representation of the rdataset into
+	 * the buffer.  If the buffer is too small, grow it.
+	 */
+	for (;;) {
+		int newlength;
+		void *newmem;
+		result = rdataset_totext(rdataset, name, ctx, false, buffer);
+		if (result != ISC_R_NOSPACE) {
+			break;
+		}
+
+		newlength = buffer->length * 2;
+		newmem = isc_mem_get(mctx, newlength);
+		isc_mem_put(mctx, buffer->base, buffer->length);
+		isc_buffer_init(buffer, newmem, newlength);
+	}
+	if (result != ISC_R_SUCCESS) {
+		return (result);
+	}
+
+	/*
+	 * Write the buffer contents to the master file.
+	 */
+	isc_buffer_usedregion(buffer, &r);
+	result = isc_stdio_write(r.base, 1, (size_t)r.length, f, NULL);
+
+	if (result != ISC_R_SUCCESS) {
+		UNEXPECTED_ERROR("master file write failed: %s",
+				 isc_result_totext(result));
+		return (result);
+	}
+
+	return (ISC_R_SUCCESS);
+}
+
+/*
+ * Define the order in which rdatasets should be printed in zone
+ * files.  We will print SOA and NS records before others, SIGs
+ * immediately following the things they sign, and order everything
+ * else by RR number.  This is all just for aesthetics and
+ * compatibility with buggy software that expects the SOA to be first;
+ * the DNS specifications allow any order.
+ */
+
+static int
+dump_order(const dns_rdataset_t *rds) {
+	int t;
+	int sig;
+	if (rds->type == dns_rdatatype_rrsig) {
+		t = rds->covers;
+		sig = 1;
+	} else {
+		t = rds->type;
+		sig = 0;
+	}
+	switch (t) {
+	case dns_rdatatype_soa:
+		t = 0;
+		break;
+	case dns_rdatatype_ns:
+		t = 1;
+		break;
+	default:
+		t += 2;
+		break;
+	}
+	return ((t << 1) + sig);
+}
+
+static int
+dump_order_compare(const void *a, const void *b) {
+	return (dump_order(*((const dns_rdataset_t *const *)a)) -
+		dump_order(*((const dns_rdataset_t *const *)b)));
+}
+
+/*
+ * Dump all the rdatasets of a domain name to a master file.  We make
+ * a "best effort" attempt to sort the RRsets in a nice order, but if
+ * there are more than MAXSORT RRsets, we punt and only sort them in
+ * groups of MAXSORT.  This is not expected to ever happen in practice
+ * since much less than 64 RR types have been registered with the
+ * IANA, so far, and the output will be correct (though not
+ * aesthetically pleasing) even if it does happen.
+ */
+
+#define MAXSORT 64
+
+static isc_result_t
+dump_rdatasets_text(isc_mem_t *mctx, const dns_name_t *name,
+		    dns_rdatasetiter_t *rdsiter, dns_totext_ctx_t *ctx,
+		    isc_buffer_t *buffer, FILE *f) {
+	isc_result_t itresult, dumpresult;
+	isc_region_t r;
+	dns_rdataset_t rdatasets[MAXSORT];
+	dns_rdataset_t *sorted[MAXSORT];
+	int i, n;
+
+	itresult = dns_rdatasetiter_first(rdsiter);
+	dumpresult = ISC_R_SUCCESS;
+
+	if (itresult == ISC_R_SUCCESS && ctx->neworigin != NULL) {
+		isc_buffer_clear(buffer);
+		itresult = dns_name_totext(ctx->neworigin, false, buffer);
+		RUNTIME_CHECK(itresult == ISC_R_SUCCESS);
+		isc_buffer_usedregion(buffer, &r);
+		fprintf(f, "$ORIGIN %.*s\n", (int)r.length, (char *)r.base);
+		ctx->neworigin = NULL;
+	}
+
+again:
+	for (i = 0; itresult == ISC_R_SUCCESS && i < MAXSORT;
+	     itresult = dns_rdatasetiter_next(rdsiter), i++)
+	{
+		dns_rdataset_init(&rdatasets[i]);
+		dns_rdatasetiter_current(rdsiter, &rdatasets[i]);
+		sorted[i] = &rdatasets[i];
+	}
+	n = i;
+	INSIST(n <= MAXSORT);
+
+	qsort(sorted, n, sizeof(sorted[0]), dump_order_compare);
+
+	for (i = 0; i < n; i++) {
+		dns_rdataset_t *rds = sorted[i];
+
+		if (ANCIENT(rds) &&
+		    (ctx->style.flags & DNS_STYLEFLAG_EXPIRED) == 0)
+		{
+			/* Omit expired entries */
+			dns_rdataset_disassociate(rds);
+			continue;
+		}
+
+		if ((ctx->style.flags & DNS_STYLEFLAG_TRUST) != 0) {
+			if ((ctx->style.flags & DNS_STYLEFLAG_INDENT) != 0 ||
+			    (ctx->style.flags & DNS_STYLEFLAG_YAML) != 0)
+			{
+				unsigned int j;
+				for (j = 0; j < ctx->indent.count; j++) {
+					fprintf(f, "%s", ctx->indent.string);
+				}
+			}
+			fprintf(f, "; %s\n", dns_trust_totext(rds->trust));
+		}
+		if (((rds->attributes & DNS_RDATASETATTR_NEGATIVE) != 0) &&
+		    (ctx->style.flags & DNS_STYLEFLAG_NCACHE) == 0)
+		{
+			/* Omit negative cache entries */
+		} else {
+			isc_result_t result;
+			if (STALE(rds)) {
+				fprintf(f, "; stale\n");
+			} else if (ANCIENT(rds)) {
+				isc_buffer_t b;
+				char buf[sizeof("YYYYMMDDHHMMSS")];
+				memset(buf, 0, sizeof(buf));
+				isc_buffer_init(&b, buf, sizeof(buf) - 1);
+				dns_time64_totext((uint64_t)rds->ttl, &b);
+				fprintf(f,
+					"; expired since %s "
+					"(awaiting cleanup)\n",
+					buf);
+			}
+			result = dump_rdataset(mctx, name, rds, ctx, buffer, f);
+			if (result != ISC_R_SUCCESS) {
+				dumpresult = result;
+			}
+			if ((ctx->style.flags & DNS_STYLEFLAG_OMIT_OWNER) != 0)
+			{
+				name = NULL;
+			}
+		}
+		if (((ctx->style.flags & DNS_STYLEFLAG_RESIGN) != 0) &&
+		    ((rds->attributes & DNS_RDATASETATTR_RESIGN) != 0))
+		{
+			isc_buffer_t b;
+			char buf[sizeof("YYYYMMDDHHMMSS")];
+			memset(buf, 0, sizeof(buf));
+			isc_buffer_init(&b, buf, sizeof(buf) - 1);
+			dns_time64_totext((uint64_t)rds->resign, &b);
+			if ((ctx->style.flags & DNS_STYLEFLAG_INDENT) != 0 ||
+			    (ctx->style.flags & DNS_STYLEFLAG_YAML) != 0)
+			{
+				unsigned int j;
+				for (j = 0; j < ctx->indent.count; j++) {
+					fprintf(f, "%s", ctx->indent.string);
+				}
+			}
+			fprintf(f, "; resign=%s\n", buf);
+		}
+		dns_rdataset_disassociate(rds);
+	}
+
+	if (dumpresult != ISC_R_SUCCESS) {
+		return (dumpresult);
+	}
+
+	/*
+	 * If we got more data than could be sorted at once,
+	 * go handle the rest.
+	 */
+	if (itresult == ISC_R_SUCCESS) {
+		goto again;
+	}
+
+	if (itresult == ISC_R_NOMORE) {
+		itresult = ISC_R_SUCCESS;
+	}
+
+	return (itresult);
+}
+
+/*
+ * Dump given RRsets in the "raw" format.
+ */
+static isc_result_t
+dump_rdataset_raw(isc_mem_t *mctx, const dns_name_t *name,
+		  dns_rdataset_t *rdataset, isc_buffer_t *buffer, FILE *f) {
+	isc_result_t result;
+	uint32_t totallen;
+	uint16_t dlen;
+	isc_region_t r, r_hdr;
+
+	REQUIRE(buffer->length > 0);
+	REQUIRE(DNS_RDATASET_VALID(rdataset));
+
+	rdataset->attributes |= DNS_RDATASETATTR_LOADORDER;
+restart:
+	totallen = 0;
+	result = dns_rdataset_first(rdataset);
+	REQUIRE(result == ISC_R_SUCCESS);
+
+	isc_buffer_clear(buffer);
+
+	/*
+	 * Common header and owner name (length followed by name)
+	 * These fields should be in a moderate length, so we assume we
+	 * can store all of them in the initial buffer.
+	 */
+	isc_buffer_availableregion(buffer, &r_hdr);
+	INSIST(r_hdr.length >= sizeof(dns_masterrawrdataset_t));
+	isc_buffer_putuint32(buffer, totallen);		 /* XXX: leave space */
+	isc_buffer_putuint16(buffer, rdataset->rdclass); /* 16-bit class */
+	isc_buffer_putuint16(buffer, rdataset->type);	 /* 16-bit type */
+	isc_buffer_putuint16(buffer, rdataset->covers);	 /* same as type */
+	isc_buffer_putuint32(buffer, rdataset->ttl);	 /* 32-bit TTL */
+	isc_buffer_putuint32(buffer, dns_rdataset_count(rdataset));
+	totallen = isc_buffer_usedlength(buffer);
+	INSIST(totallen <= sizeof(dns_masterrawrdataset_t));
+
+	dns_name_toregion(name, &r);
+	INSIST(isc_buffer_availablelength(buffer) >= (sizeof(dlen) + r.length));
+	dlen = (uint16_t)r.length;
+	isc_buffer_putuint16(buffer, dlen);
+	isc_buffer_copyregion(buffer, &r);
+	totallen += sizeof(dlen) + r.length;
+
+	do {
+		dns_rdata_t rdata = DNS_RDATA_INIT;
+
+		dns_rdataset_current(rdataset, &rdata);
+		dns_rdata_toregion(&rdata, &r);
+		INSIST(r.length <= 0xffffU);
+		dlen = (uint16_t)r.length;
+
+		/*
+		 * Copy the rdata into the buffer.  If the buffer is too small,
+		 * grow it.  This should be rare, so we'll simply restart the
+		 * entire procedure (or should we copy the old data and
+		 * continue?).
+		 */
+		if (isc_buffer_availablelength(buffer) <
+		    sizeof(dlen) + r.length)
+		{
+			int newlength;
+			void *newmem;
+
+			newlength = buffer->length * 2;
+			newmem = isc_mem_get(mctx, newlength);
+			isc_mem_put(mctx, buffer->base, buffer->length);
+			isc_buffer_init(buffer, newmem, newlength);
+			goto restart;
+		}
+		isc_buffer_putuint16(buffer, dlen);
+		isc_buffer_copyregion(buffer, &r);
+		totallen += sizeof(dlen) + r.length;
+
+		result = dns_rdataset_next(rdataset);
+	} while (result == ISC_R_SUCCESS);
+
+	if (result != ISC_R_NOMORE) {
+		return (result);
+	}
+
+	/*
+	 * Fill in the total length field.
+	 * XXX: this is a bit tricky.  Since we have already "used" the space
+	 * for the total length in the buffer, we first remember the entire
+	 * buffer length in the region, "rewind", and then write the value.
+	 */
+	isc_buffer_usedregion(buffer, &r);
+	isc_buffer_clear(buffer);
+	isc_buffer_putuint32(buffer, totallen);
+	INSIST(isc_buffer_usedlength(buffer) < totallen);
+
+	/*
+	 * Write the buffer contents to the raw master file.
+	 */
+	result = isc_stdio_write(r.base, 1, (size_t)r.length, f, NULL);
+
+	if (result != ISC_R_SUCCESS) {
+		UNEXPECTED_ERROR("raw master file write failed: %s",
+				 isc_result_totext(result));
+		return (result);
+	}
+
+	return (result);
+}
+
+static isc_result_t
+dump_rdatasets_raw(isc_mem_t *mctx, const dns_name_t *owner_name,
+		   dns_rdatasetiter_t *rdsiter, dns_totext_ctx_t *ctx,
+		   isc_buffer_t *buffer, FILE *f) {
+	isc_result_t result;
+	dns_rdataset_t rdataset;
+	dns_fixedname_t fixed;
+	dns_name_t *name;
+
+	name = dns_fixedname_initname(&fixed);
+	dns_name_copy(owner_name, name);
+	for (result = dns_rdatasetiter_first(rdsiter); result == ISC_R_SUCCESS;
+	     result = dns_rdatasetiter_next(rdsiter))
+	{
+		dns_rdataset_init(&rdataset);
+		dns_rdatasetiter_current(rdsiter, &rdataset);
+
+		dns_rdataset_getownercase(&rdataset, name);
+
+		if (((rdataset.attributes & DNS_RDATASETATTR_NEGATIVE) != 0) &&
+		    (ctx->style.flags & DNS_STYLEFLAG_NCACHE) == 0)
+		{
+			/* Omit negative cache entries */
+		} else {
+			result = dump_rdataset_raw(mctx, name, &rdataset,
+						   buffer, f);
+		}
+		dns_rdataset_disassociate(&rdataset);
+		if (result != ISC_R_SUCCESS) {
+			return (result);
+		}
+	}
+
+	if (result == ISC_R_NOMORE) {
+		result = ISC_R_SUCCESS;
+	}
+
+	return (result);
+}
+
+/*
+ * Initial size of text conversion buffer.  The buffer is used
+ * for several purposes: converting origin names, rdatasets,
+ * $DATE timestamps, and comment strings for $TTL directives.
+ *
+ * When converting rdatasets, it is dynamically resized, but
+ * when converting origins, timestamps, etc it is not.  Therefore,
+ * the initial size must large enough to hold the longest possible
+ * text representation of any domain name (for $ORIGIN).
+ */
+static const int initial_buffer_length = 1200;
+
+static isc_result_t
+dumptostream(dns_dumpctx_t *dctx);
+
+static void
+dumpctx_destroy(dns_dumpctx_t *dctx) {
+	dctx->magic = 0;
+	isc_mutex_destroy(&dctx->lock);
+	dns_dbiterator_destroy(&dctx->dbiter);
+	if (dctx->version != NULL) {
+		dns_db_closeversion(dctx->db, &dctx->version, false);
+	}
+	dns_db_detach(&dctx->db);
+	if (dctx->task != NULL) {
+		isc_task_detach(&dctx->task);
+	}
+	if (dctx->file != NULL) {
+		isc_mem_free(dctx->mctx, dctx->file);
+	}
+	if (dctx->tmpfile != NULL) {
+		isc_mem_free(dctx->mctx, dctx->tmpfile);
+	}
+	isc_mem_putanddetach(&dctx->mctx, dctx, sizeof(*dctx));
+}
+
+void
+dns_dumpctx_attach(dns_dumpctx_t *source, dns_dumpctx_t **target) {
+	REQUIRE(DNS_DCTX_VALID(source));
+	REQUIRE(target != NULL && *target == NULL);
+
+	isc_refcount_increment(&source->references);
+
+	*target = source;
+}
+
+void
+dns_dumpctx_detach(dns_dumpctx_t **dctxp) {
+	dns_dumpctx_t *dctx;
+
+	REQUIRE(dctxp != NULL);
+	dctx = *dctxp;
+	*dctxp = NULL;
+	REQUIRE(DNS_DCTX_VALID(dctx));
+
+	if (isc_refcount_decrement(&dctx->references) == 1) {
+		dumpctx_destroy(dctx);
+	}
+}
+
+dns_dbversion_t *
+dns_dumpctx_version(dns_dumpctx_t *dctx) {
+	REQUIRE(DNS_DCTX_VALID(dctx));
+	return (dctx->version);
+}
+
+dns_db_t *
+dns_dumpctx_db(dns_dumpctx_t *dctx) {
+	REQUIRE(DNS_DCTX_VALID(dctx));
+	return (dctx->db);
+}
+
+void
+dns_dumpctx_cancel(dns_dumpctx_t *dctx) {
+	REQUIRE(DNS_DCTX_VALID(dctx));
+
+	atomic_store_release(&dctx->canceled, true);
+}
+
+static isc_result_t
+flushandsync(FILE *f, isc_result_t result, const char *temp) {
+	bool logit = (result == ISC_R_SUCCESS);
+
+	if (result == ISC_R_SUCCESS) {
+		result = isc_stdio_flush(f);
+	}
+	if (result != ISC_R_SUCCESS && logit) {
+		if (temp != NULL) {
+			isc_log_write(dns_lctx, ISC_LOGCATEGORY_GENERAL,
+				      DNS_LOGMODULE_MASTERDUMP, ISC_LOG_ERROR,
+				      "dumping to master file: %s: flush: %s",
+				      temp, isc_result_totext(result));
+		} else {
+			isc_log_write(dns_lctx, ISC_LOGCATEGORY_GENERAL,
+				      DNS_LOGMODULE_MASTERDUMP, ISC_LOG_ERROR,
+				      "dumping to stream: flush: %s",
+				      isc_result_totext(result));
+		}
+		logit = false;
+	}
+
+	if (result == ISC_R_SUCCESS) {
+		result = isc_stdio_sync(f);
+	}
+	if (result != ISC_R_SUCCESS && logit) {
+		if (temp != NULL) {
+			isc_log_write(dns_lctx, ISC_LOGCATEGORY_GENERAL,
+				      DNS_LOGMODULE_MASTERDUMP, ISC_LOG_ERROR,
+				      "dumping to master file: %s: fsync: %s",
+				      temp, isc_result_totext(result));
+		} else {
+			isc_log_write(dns_lctx, ISC_LOGCATEGORY_GENERAL,
+				      DNS_LOGMODULE_MASTERDUMP, ISC_LOG_ERROR,
+				      "dumping to stream: fsync: %s",
+				      isc_result_totext(result));
+		}
+	}
+	return (result);
+}
+
+static isc_result_t
+closeandrename(FILE *f, isc_result_t result, const char *temp,
+	       const char *file) {
+	isc_result_t tresult;
+	bool logit = (result == ISC_R_SUCCESS);
+
+	result = flushandsync(f, result, temp);
+	if (result != ISC_R_SUCCESS) {
+		logit = false;
+	}
+
+	tresult = isc_stdio_close(f);
+	if (result == ISC_R_SUCCESS) {
+		result = tresult;
+	}
+	if (result != ISC_R_SUCCESS && logit) {
+		isc_log_write(dns_lctx, ISC_LOGCATEGORY_GENERAL,
+			      DNS_LOGMODULE_MASTERDUMP, ISC_LOG_ERROR,
+			      "dumping master file: %s: fclose: %s", temp,
+			      isc_result_totext(result));
+		logit = false;
+	}
+	if (result == ISC_R_SUCCESS) {
+		result = isc_file_rename(temp, file);
+	} else {
+		(void)isc_file_remove(temp);
+	}
+	if (result != ISC_R_SUCCESS && logit) {
+		isc_log_write(dns_lctx, ISC_LOGCATEGORY_GENERAL,
+			      DNS_LOGMODULE_MASTERDUMP, ISC_LOG_ERROR,
+			      "dumping master file: rename: %s: %s", file,
+			      isc_result_totext(result));
+	}
+	return (result);
+}
+
+/*
+ * This will run in a libuv threadpool thread.
+ */
+static void
+master_dump_cb(void *data) {
+	isc_result_t result = ISC_R_UNSET;
+	dns_dumpctx_t *dctx = data;
+	REQUIRE(DNS_DCTX_VALID(dctx));
+
+	if (atomic_load_acquire(&dctx->canceled)) {
+		result = ISC_R_CANCELED;
+	} else {
+		result = dumptostream(dctx);
+	}
+
+	if (dctx->file != NULL) {
+		isc_result_t tresult = ISC_R_UNSET;
+		tresult = closeandrename(dctx->f, result, dctx->tmpfile,
+					 dctx->file);
+		if (tresult != ISC_R_SUCCESS && result == ISC_R_SUCCESS) {
+			result = tresult;
+		}
+	} else {
+		result = flushandsync(dctx->f, result, NULL);
+	}
+
+	dctx->result = result;
+}
+
+/*
+ * This will run in a network/task manager thread when the dump is complete.
+ */
+static void
+master_dump_done_cb(void *data, isc_result_t result) {
+	dns_dumpctx_t *dctx = data;
+
+	if (result == ISC_R_SUCCESS && dctx->result != ISC_R_SUCCESS) {
+		result = dctx->result;
+	}
+
+	(dctx->done)(dctx->done_arg, result);
+	dns_dumpctx_detach(&dctx);
+}
+
+/*
+ * This must be run from a network/task manager thread.
+ */
+static void
+setup_dump(isc_task_t *task, isc_event_t *event) {
+	dns_dumpctx_t *dctx = NULL;
+
+	REQUIRE(isc_nm_tid() >= 0);
+	REQUIRE(event != NULL);
+
+	dctx = event->ev_arg;
+
+	REQUIRE(DNS_DCTX_VALID(dctx));
+
+	isc_nm_work_offload(isc_task_getnetmgr(task), master_dump_cb,
+			    master_dump_done_cb, dctx);
+
+	isc_event_free(&event);
+}
+
+static isc_result_t
+task_send(dns_dumpctx_t *dctx) {
+	isc_event_t *event;
+
+	event = isc_event_allocate(dctx->mctx, NULL, DNS_EVENT_DUMPQUANTUM,
+				   setup_dump, dctx, sizeof(*event));
+	isc_task_send(dctx->task, &event);
+	return (ISC_R_SUCCESS);
+}
+
+static isc_result_t
+dumpctx_create(isc_mem_t *mctx, dns_db_t *db, dns_dbversion_t *version,
+	       const dns_master_style_t *style, FILE *f, dns_dumpctx_t **dctxp,
+	       dns_masterformat_t format, dns_masterrawheader_t *header) {
+	dns_dumpctx_t *dctx;
+	isc_result_t result;
+	unsigned int options;
+
+	dctx = isc_mem_get(mctx, sizeof(*dctx));
+
+	dctx->mctx = NULL;
+	dctx->f = f;
+	dctx->dbiter = NULL;
+	dctx->db = NULL;
+	dctx->version = NULL;
+	dctx->done = NULL;
+	dctx->done_arg = NULL;
+	dctx->task = NULL;
+	atomic_init(&dctx->canceled, false);
+	dctx->file = NULL;
+	dctx->tmpfile = NULL;
+	dctx->format = format;
+	if (header == NULL) {
+		dns_master_initrawheader(&dctx->header);
+	} else {
+		dctx->header = *header;
+	}
+
+	switch (format) {
+	case dns_masterformat_text:
+		dctx->dumpsets = dump_rdatasets_text;
+		break;
+	case dns_masterformat_raw:
+		dctx->dumpsets = dump_rdatasets_raw;
+		break;
+	default:
+		UNREACHABLE();
+	}
+
+	result = totext_ctx_init(style, NULL, &dctx->tctx);
+	if (result != ISC_R_SUCCESS) {
+		UNEXPECTED_ERROR("could not set master file style");
+		goto cleanup;
+	}
+
+	isc_stdtime_get(&dctx->now);
+	dns_db_attach(db, &dctx->db);
+
+	dctx->do_date = dns_db_iscache(dctx->db);
+	if (dctx->do_date) {
+		(void)dns_db_getservestalettl(dctx->db,
+					      &dctx->tctx.serve_stale_ttl);
+	}
+
+	if (dctx->format == dns_masterformat_text &&
+	    (dctx->tctx.style.flags & DNS_STYLEFLAG_REL_OWNER) != 0)
+	{
+		options = DNS_DB_RELATIVENAMES;
+	} else {
+		options = 0;
+	}
+	result = dns_db_createiterator(dctx->db, options, &dctx->dbiter);
+	if (result != ISC_R_SUCCESS) {
+		goto cleanup;
+	}
+
+	isc_mutex_init(&dctx->lock);
+
+	if (version != NULL) {
+		dns_db_attachversion(dctx->db, version, &dctx->version);
+	} else if (!dns_db_iscache(db)) {
+		dns_db_currentversion(dctx->db, &dctx->version);
+	}
+	isc_mem_attach(mctx, &dctx->mctx);
+
+	isc_refcount_init(&dctx->references, 1);
+	dctx->magic = DNS_DCTX_MAGIC;
+	*dctxp = dctx;
+	return (ISC_R_SUCCESS);
+
+cleanup:
+	if (dctx->dbiter != NULL) {
+		dns_dbiterator_destroy(&dctx->dbiter);
+	}
+	if (dctx->db != NULL) {
+		dns_db_detach(&dctx->db);
+	}
+	isc_mem_put(mctx, dctx, sizeof(*dctx));
+	return (result);
+}
+
+static isc_result_t
+writeheader(dns_dumpctx_t *dctx) {
+	isc_result_t result = ISC_R_SUCCESS;
+	isc_buffer_t buffer;
+	char *bufmem;
+	isc_region_t r;
+	dns_masterrawheader_t rawheader;
+	uint32_t rawversion, now32;
+
+	bufmem = isc_mem_get(dctx->mctx, initial_buffer_length);
+
+	isc_buffer_init(&buffer, bufmem, initial_buffer_length);
+
+	switch (dctx->format) {
+	case dns_masterformat_text:
+		/*
+		 * If the database has cache semantics, output an
+		 * RFC2540 $DATE directive so that the TTLs can be
+		 * adjusted when it is reloaded.  For zones it is not
+		 * really needed, and it would make the file
+		 * incompatible with pre-RFC2540 software, so we omit
+		 * it in the zone case.
+		 */
+		if (dctx->do_date) {
+			fprintf(dctx->f, "; using a %u second stale ttl\n",
+				dctx->tctx.serve_stale_ttl);
+			result = dns_time32_totext(dctx->now, &buffer);
+			RUNTIME_CHECK(result == ISC_R_SUCCESS);
+			isc_buffer_usedregion(&buffer, &r);
+			fprintf(dctx->f, "$DATE %.*s\n", (int)r.length,
+				(char *)r.base);
+		}
+		break;
+	case dns_masterformat_raw:
+		r.base = (unsigned char *)&rawheader;
+		r.length = sizeof(rawheader);
+		isc_buffer_region(&buffer, &r);
+		now32 = dctx->now;
+		rawversion = 1;
+		if ((dctx->header.flags & DNS_MASTERRAW_COMPAT) != 0) {
+			rawversion = 0;
+		}
+
+		isc_buffer_putuint32(&buffer, dctx->format);
+		isc_buffer_putuint32(&buffer, rawversion);
+		isc_buffer_putuint32(&buffer, now32);
+
+		if (rawversion == 1) {
+			isc_buffer_putuint32(&buffer, dctx->header.flags);
+			isc_buffer_putuint32(&buffer,
+					     dctx->header.sourceserial);
+			isc_buffer_putuint32(&buffer, dctx->header.lastxfrin);
+		}
+
+		INSIST(isc_buffer_usedlength(&buffer) <= sizeof(rawheader));
+		result = isc_stdio_write(buffer.base, 1,
+					 isc_buffer_usedlength(&buffer),
+					 dctx->f, NULL);
+		if (result != ISC_R_SUCCESS) {
+			break;
+		}
+
+		break;
+	default:
+		UNREACHABLE();
+	}
+
+	isc_mem_put(dctx->mctx, buffer.base, buffer.length);
+	return (result);
+}
+
+static isc_result_t
+dumptostream(dns_dumpctx_t *dctx) {
+	isc_result_t result = ISC_R_SUCCESS;
+	isc_buffer_t buffer;
+	char *bufmem;
+	dns_name_t *name;
+	dns_fixedname_t fixname;
+	unsigned int options = DNS_DB_STALEOK;
+
+	if ((dctx->tctx.style.flags & DNS_STYLEFLAG_EXPIRED) != 0) {
+		options |= DNS_DB_EXPIREDOK;
+	}
+
+	bufmem = isc_mem_get(dctx->mctx, initial_buffer_length);
+
+	isc_buffer_init(&buffer, bufmem, initial_buffer_length);
+
+	name = dns_fixedname_initname(&fixname);
+
+	CHECK(writeheader(dctx));
+
+	result = dns_dbiterator_first(dctx->dbiter);
+	if (result != ISC_R_SUCCESS && result != ISC_R_NOMORE) {
+		goto cleanup;
+	}
+
+	while (result == ISC_R_SUCCESS) {
+		dns_rdatasetiter_t *rdsiter = NULL;
+		dns_dbnode_t *node = NULL;
+
+		result = dns_dbiterator_current(dctx->dbiter, &node, name);
+		if (result != ISC_R_SUCCESS && result != DNS_R_NEWORIGIN) {
+			break;
+		}
+		if (result == DNS_R_NEWORIGIN) {
+			dns_name_t *origin =
+				dns_fixedname_name(&dctx->tctx.origin_fixname);
+			result = dns_dbiterator_origin(dctx->dbiter, origin);
+			RUNTIME_CHECK(result == ISC_R_SUCCESS);
+			if ((dctx->tctx.style.flags & DNS_STYLEFLAG_REL_DATA) !=
+			    0)
+			{
+				dctx->tctx.origin = origin;
+			}
+			dctx->tctx.neworigin = origin;
+		}
+
+		result = dns_dbiterator_pause(dctx->dbiter);
+		RUNTIME_CHECK(result == ISC_R_SUCCESS);
+
+		result = dns_db_allrdatasets(dctx->db, node, dctx->version,
+					     options, dctx->now, &rdsiter);
+		if (result != ISC_R_SUCCESS) {
+			dns_db_detachnode(dctx->db, &node);
+			goto cleanup;
+		}
+		result = (dctx->dumpsets)(dctx->mctx, name, rdsiter,
+					  &dctx->tctx, &buffer, dctx->f);
+		dns_rdatasetiter_destroy(&rdsiter);
+		if (result != ISC_R_SUCCESS) {
+			dns_db_detachnode(dctx->db, &node);
+			goto cleanup;
+		}
+		dns_db_detachnode(dctx->db, &node);
+		result = dns_dbiterator_next(dctx->dbiter);
+	}
+
+	if (result == ISC_R_NOMORE) {
+		result = ISC_R_SUCCESS;
+	}
+cleanup:
+	RUNTIME_CHECK(dns_dbiterator_pause(dctx->dbiter) == ISC_R_SUCCESS);
+	isc_mem_put(dctx->mctx, buffer.base, buffer.length);
+	return (result);
+}
+
+isc_result_t
+dns_master_dumptostreamasync(isc_mem_t *mctx, dns_db_t *db,
+			     dns_dbversion_t *version,
+			     const dns_master_style_t *style, FILE *f,
+			     isc_task_t *task, dns_dumpdonefunc_t done,
+			     void *done_arg, dns_dumpctx_t **dctxp) {
+	dns_dumpctx_t *dctx = NULL;
+	isc_result_t result;
+
+	REQUIRE(task != NULL);
+	REQUIRE(f != NULL);
+	REQUIRE(done != NULL);
+
+	result = dumpctx_create(mctx, db, version, style, f, &dctx,
+				dns_masterformat_text, NULL);
+	if (result != ISC_R_SUCCESS) {
+		return (result);
+	}
+	isc_task_attach(task, &dctx->task);
+	dctx->done = done;
+	dctx->done_arg = done_arg;
+
+	result = task_send(dctx);
+	if (result == ISC_R_SUCCESS) {
+		dns_dumpctx_attach(dctx, dctxp);
+		return (DNS_R_CONTINUE);
+	}
+
+	dns_dumpctx_detach(&dctx);
+	return (result);
+}
+
+isc_result_t
+dns_master_dumptostream(isc_mem_t *mctx, dns_db_t *db, dns_dbversion_t *version,
+			const dns_master_style_t *style,
+			dns_masterformat_t format,
+			dns_masterrawheader_t *header, FILE *f) {
+	dns_dumpctx_t *dctx = NULL;
+	isc_result_t result;
+
+	result = dumpctx_create(mctx, db, version, style, f, &dctx, format,
+				header);
+	if (result != ISC_R_SUCCESS) {
+		return (result);
+	}
+
+	result = dumptostream(dctx);
+	INSIST(result != DNS_R_CONTINUE);
+	dns_dumpctx_detach(&dctx);
+
+	result = flushandsync(f, result, NULL);
+	return (result);
+}
+
+static isc_result_t
+opentmp(isc_mem_t *mctx, dns_masterformat_t format, const char *file,
+	char **tempp, FILE **fp) {
+	FILE *f = NULL;
+	isc_result_t result;
+	char *tempname = NULL;
+	int tempnamelen;
+
+	tempnamelen = strlen(file) + 20;
+	tempname = isc_mem_allocate(mctx, tempnamelen);
+
+	result = isc_file_mktemplate(file, tempname, tempnamelen);
+	if (result != ISC_R_SUCCESS) {
+		goto cleanup;
+	}
+
+	if (format == dns_masterformat_text) {
+		result = isc_file_openunique(tempname, &f);
+	} else {
+		result = isc_file_bopenunique(tempname, &f);
+	}
+	if (result != ISC_R_SUCCESS) {
+		isc_log_write(dns_lctx, ISC_LOGCATEGORY_GENERAL,
+			      DNS_LOGMODULE_MASTERDUMP, ISC_LOG_ERROR,
+			      "dumping master file: %s: open: %s", tempname,
+			      isc_result_totext(result));
+		goto cleanup;
+	}
+
+#if defined(POSIX_FADV_DONTNEED)
+	posix_fadvise(fileno(f), 0, 0, POSIX_FADV_DONTNEED);
+#endif
+
+	*tempp = tempname;
+	*fp = f;
+	return (ISC_R_SUCCESS);
+
+cleanup:
+	isc_mem_free(mctx, tempname);
+	return (result);
+}
+
+isc_result_t
+dns_master_dumpasync(isc_mem_t *mctx, dns_db_t *db, dns_dbversion_t *version,
+		     const dns_master_style_t *style, const char *filename,
+		     isc_task_t *task, dns_dumpdonefunc_t done, void *done_arg,
+		     dns_dumpctx_t **dctxp, dns_masterformat_t format,
+		     dns_masterrawheader_t *header) {
+	FILE *f = NULL;
+	isc_result_t result;
+	char *tempname = NULL;
+	char *file = NULL;
+	dns_dumpctx_t *dctx = NULL;
+
+	file = isc_mem_strdup(mctx, filename);
+
+	result = opentmp(mctx, format, filename, &tempname, &f);
+	if (result != ISC_R_SUCCESS) {
+		goto cleanup;
+	}
+
+	result = dumpctx_create(mctx, db, version, style, f, &dctx, format,
+				header);
+	if (result != ISC_R_SUCCESS) {
+		(void)isc_stdio_close(f);
+		(void)isc_file_remove(tempname);
+		goto cleanup;
+	}
+
+	isc_task_attach(task, &dctx->task);
+	dctx->done = done;
+	dctx->done_arg = done_arg;
+	dctx->file = file;
+	file = NULL;
+	dctx->tmpfile = tempname;
+	tempname = NULL;
+
+	result = task_send(dctx);
+	if (result == ISC_R_SUCCESS) {
+		dns_dumpctx_attach(dctx, dctxp);
+		return (DNS_R_CONTINUE);
+	}
+
+cleanup:
+	if (dctx != NULL) {
+		dns_dumpctx_detach(&dctx);
+	}
+	if (file != NULL) {
+		isc_mem_free(mctx, file);
+	}
+	if (tempname != NULL) {
+		isc_mem_free(mctx, tempname);
+	}
+	return (result);
+}
+
+isc_result_t
+dns_master_dump(isc_mem_t *mctx, dns_db_t *db, dns_dbversion_t *version,
+		const dns_master_style_t *style, const char *filename,
+		dns_masterformat_t format, dns_masterrawheader_t *header) {
+	FILE *f = NULL;
+	isc_result_t result;
+	char *tempname;
+	dns_dumpctx_t *dctx = NULL;
+
+	result = opentmp(mctx, format, filename, &tempname, &f);
+	if (result != ISC_R_SUCCESS) {
+		return (result);
+	}
+
+	result = dumpctx_create(mctx, db, version, style, f, &dctx, format,
+				header);
+	if (result != ISC_R_SUCCESS) {
+		goto cleanup;
+	}
+
+	result = dumptostream(dctx);
+	INSIST(result != DNS_R_CONTINUE);
+	dns_dumpctx_detach(&dctx);
+
+	result = closeandrename(f, result, tempname, filename);
+
+cleanup:
+	isc_mem_free(mctx, tempname);
+	return (result);
+}
+
+/*
+ * Dump a database node into a master file.
+ * XXX: this function assumes the text format.
+ */
+isc_result_t
+dns_master_dumpnodetostream(isc_mem_t *mctx, dns_db_t *db,
+			    dns_dbversion_t *version, dns_dbnode_t *node,
+			    const dns_name_t *name,
+			    const dns_master_style_t *style, FILE *f) {
+	isc_result_t result;
+	isc_buffer_t buffer;
+	char *bufmem;
+	isc_stdtime_t now;
+	dns_totext_ctx_t ctx;
+	dns_rdatasetiter_t *rdsiter = NULL;
+	unsigned int options = DNS_DB_STALEOK;
+
+	if ((style->flags & DNS_STYLEFLAG_EXPIRED) != 0) {
+		options |= DNS_DB_EXPIREDOK;
+	}
+
+	result = totext_ctx_init(style, NULL, &ctx);
+	if (result != ISC_R_SUCCESS) {
+		UNEXPECTED_ERROR("could not set master file style");
+		return (ISC_R_UNEXPECTED);
+	}
+
+	isc_stdtime_get(&now);
+
+	bufmem = isc_mem_get(mctx, initial_buffer_length);
+
+	isc_buffer_init(&buffer, bufmem, initial_buffer_length);
+
+	result = dns_db_allrdatasets(db, node, version, options, now, &rdsiter);
+	if (result != ISC_R_SUCCESS) {
+		goto failure;
+	}
+	result = dump_rdatasets_text(mctx, name, rdsiter, &ctx, &buffer, f);
+	if (result != ISC_R_SUCCESS) {
+		goto failure;
+	}
+	dns_rdatasetiter_destroy(&rdsiter);
+
+	result = ISC_R_SUCCESS;
+
+failure:
+	isc_mem_put(mctx, buffer.base, buffer.length);
+	return (result);
+}
+
+isc_result_t
+dns_master_dumpnode(isc_mem_t *mctx, dns_db_t *db, dns_dbversion_t *version,
+		    dns_dbnode_t *node, const dns_name_t *name,
+		    const dns_master_style_t *style, const char *filename) {
+	FILE *f = NULL;
+	isc_result_t result;
+
+	result = isc_stdio_open(filename, "w", &f);
+	if (result != ISC_R_SUCCESS) {
+		isc_log_write(dns_lctx, ISC_LOGCATEGORY_GENERAL,
+			      DNS_LOGMODULE_MASTERDUMP, ISC_LOG_ERROR,
+			      "dumping node to file: %s: open: %s", filename,
+			      isc_result_totext(result));
+		return (ISC_R_UNEXPECTED);
+	}
+
+	result = dns_master_dumpnodetostream(mctx, db, version, node, name,
+					     style, f);
+	if (result != ISC_R_SUCCESS) {
+		isc_log_write(dns_lctx, ISC_LOGCATEGORY_GENERAL,
+			      DNS_LOGMODULE_MASTERDUMP, ISC_LOG_ERROR,
+			      "dumping master file: %s: dump: %s", filename,
+			      isc_result_totext(result));
+		(void)isc_stdio_close(f);
+		return (ISC_R_UNEXPECTED);
+	}
+
+	result = isc_stdio_close(f);
+	if (result != ISC_R_SUCCESS) {
+		isc_log_write(dns_lctx, ISC_LOGCATEGORY_GENERAL,
+			      DNS_LOGMODULE_MASTERDUMP, ISC_LOG_ERROR,
+			      "dumping master file: %s: close: %s", filename,
+			      isc_result_totext(result));
+		return (ISC_R_UNEXPECTED);
+	}
+
+	return (result);
+}
+
+dns_masterstyle_flags_t
+dns_master_styleflags(const dns_master_style_t *style) {
+	REQUIRE(style != NULL);
+	return (style->flags);
+}
+
+isc_result_t
+dns_master_stylecreate(dns_master_style_t **stylep,
+		       dns_masterstyle_flags_t flags, unsigned int ttl_column,
+		       unsigned int class_column, unsigned int type_column,
+		       unsigned int rdata_column, unsigned int line_length,
+		       unsigned int tab_width, unsigned int split_width,
+		       isc_mem_t *mctx) {
+	dns_master_style_t *style;
+
+	REQUIRE(stylep != NULL && *stylep == NULL);
+	style = isc_mem_get(mctx, sizeof(*style));
+
+	style->flags = flags;
+	style->ttl_column = ttl_column;
+	style->class_column = class_column;
+	style->type_column = type_column;
+	style->rdata_column = rdata_column;
+	style->line_length = line_length;
+	style->tab_width = tab_width;
+	style->split_width = split_width;
+	*stylep = style;
+	return (ISC_R_SUCCESS);
+}
+
+void
+dns_master_styledestroy(dns_master_style_t **stylep, isc_mem_t *mctx) {
+	dns_master_style_t *style;
+
+	REQUIRE(stylep != NULL && *stylep != NULL);
+	style = *stylep;
+	*stylep = NULL;
+	isc_mem_put(mctx, style, sizeof(*style));
+}