masterdump.c

非常好的dns解析软件

		UNEXPECTED_ERROR(__FILE__, __LINE__,
				 "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(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, &ctx);
	if (result != ISC_R_SUCCESS) {
		UNEXPECTED_ERROR(__FILE__, __LINE__,
				 "could not set master file style");
		return (ISC_R_UNEXPECTED);
	}

	return (rdataset_totext(rdataset, owner_name, &ctx,
				ISC_FALSE, target));
}

isc_result_t
dns_master_questiontotext(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, &ctx);
	if (result != ISC_R_SUCCESS) {
		UNEXPECTED_ERROR(__FILE__, __LINE__,
				 "could not set master file style");
		return (ISC_R_UNEXPECTED);
	}

	return (question_totext(rdataset, owner_name, &ctx,
				ISC_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, 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 == ISC_FALSE ||
		    ctx->current_ttl != rdataset->ttl)
		{
			if ((ctx->style.flags & DNS_STYLEFLAG_COMMENT) != 0)
			{
				isc_buffer_clear(buffer);
				result = dns_ttl_totext(rdataset->ttl,
							ISC_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 = ISC_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,
					 ISC_FALSE, buffer);
		if (result != ISC_R_NOSPACE)
			break;

		newlength = buffer->length * 2;
		newmem = isc_mem_get(mctx, newlength);
		if (newmem == NULL)
			return (ISC_R_NOMEMORY);
		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(__FILE__, __LINE__,
				 "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 const char *trustnames[] = {
	"none",
	"pending",
	"additional",
	"glue",
	"answer",
	"authauthority",
	"authanswer",
	"secure",
	"local" /* aka ultimate */
};

static isc_result_t
dump_rdatasets_text(isc_mem_t *mctx, 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, ISC_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 (ctx->style.flags & DNS_STYLEFLAG_TRUST) {
			unsigned int trust = rds->trust;
			INSIST(trust < (sizeof(trustnames) /
					sizeof(trustnames[0])));
			fprintf(f, "; %s\n", trustnames[trust]);
		}
		if (rds->type == 0 &&
		    (ctx->style.flags & DNS_STYLEFLAG_NCACHE) == 0) {
			/* Omit negative cache entries */
		} else {
			isc_result_t 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;
		}
		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, dns_name_t *name, dns_rdataset_t *rdataset,
		  isc_buffer_t *buffer, FILE *f)
{
	isc_result_t result;
	isc_uint32_t totallen;
	isc_uint16_t dlen;
	isc_region_t r, r_hdr;

	REQUIRE(buffer->length > 0);
	REQUIRE(DNS_RDATASET_VALID(rdataset));

 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 = (isc_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;
		isc_region_t r;

		dns_rdataset_current(rdataset, &rdata);
		dns_rdata_toregion(&rdata, &r);
		INSIST(r.length <= 0xffffU);
		dlen = (isc_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);
			if (newmem == NULL)
				return (ISC_R_NOMEMORY);
			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(__FILE__, __LINE__,
				 "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, dns_name_t *name,
		   dns_rdatasetiter_t *rdsiter, dns_totext_ctx_t *ctx,
		   isc_buffer_t *buffer, FILE *f)
{
	isc_result_t result;
	dns_rdataset_t rdataset;

	for (result = dns_rdatasetiter_first(rdsiter);
	     result == ISC_R_SUCCESS;
	     result = dns_rdatasetiter_next(rdsiter)) {

		dns_rdataset_init(&rdataset);
		dns_rdatasetiter_current(rdsiter, &rdataset);

		if (rdataset.type == 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_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
dumptostreaminc(dns_dumpctx_t *dctx);

static void
dumpctx_destroy(dns_dumpctx_t *dctx) {

	dctx->magic = 0;
	DESTROYLOCK(&dctx->lock);
	if (dctx->version != NULL)
		dns_db_closeversion(dctx->db, &dctx->version, ISC_FALSE);
	dns_dbiterator_destroy(&dctx->dbiter);
	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);

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

	*target = source;
}

void
dns_dumpctx_detach(dns_dumpctx_t **dctxp) {
	dns_dumpctx_t *dctx;
	isc_boolean_t need_destroy = ISC_FALSE;

	REQUIRE(dctxp != NULL);
	dctx = *dctxp;
	REQUIRE(DNS_DCTX_VALID(dctx));

	*dctxp = NULL;

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

	LOCK(&dctx->lock);
	dctx->canceled = ISC_TRUE;
	UNLOCK(&dctx->lock);
}

static isc_result_t
closeandrename(FILE *f, isc_result_t result, const char *temp, const char *file)
{
	isc_result_t tresult;
	isc_boolean_t logit = ISC_TF(result == ISC_R_SUCCESS);

	if (result == ISC_R_SUCCESS)
		result = isc_stdio_sync(f);
	if (result != ISC_R_SUCCESS && logit) {
		isc_log_write(dns_lctx, ISC_LOGCATEGORY_GENERAL,
			      DNS_LOGMODULE_MASTERDUMP, ISC_LOG_ERROR,
			      "dumping master file: %s: fsync: %s",
			      temp, isc_result_totext(result));
		logit = ISC_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 = ISC_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);
}

static void
dump_quantum(isc_task_t *task, isc_event_t *event) {
	isc_result_t result;
	isc_result_t tresult;
	dns_dumpctx_t *dctx;

	REQUIRE(event != NULL);
	dctx = event->ev_arg;
	REQUIRE(DNS_DCTX_VALID(dctx));
	if (dctx->canceled)
		result = ISC_R_CANCELED;
	else
		result = dumptostreaminc(dctx);
	if (result == DNS_R_CONTINUE) {
		event->ev_arg = dctx;
		isc_task_send(task, &event);
		return;
	}

	if (dctx->file != NULL) {
		tresult = closeandrename(dctx->f, result,
					 dctx->tmpfile, dctx->file);
		if (tresult != ISC_R_SUCCESS && result == ISC_R_SUCCESS)
			result = tresult;
	}
	(dctx->done)(dctx->done_arg, result);
	isc_event_free(&event);
	dns_dumpctx_detach(&dctx);
}