ldb: move ldb_pack.c into common

this code should not be tied to the ldb_tdb backend, both because it
could be used for any record oriented backend, and because it should
be exposed for use by diagnosis/repair tools such as the recently
added ldbdump tool

Pair-Programmed-With: Andrew Bartlett <abartlet@samba.org>

1 files changed, 290 insertions, 0 deletions

diff --git a/lib/ldb/common/ldb_pack.c b/lib/ldb/common/ldb_pack.c
new file mode 100644
index 0000000000..03e0ec1ddf
--- /dev/null
+++ b/lib/ldb/common/ldb_pack.c
@@ -0,0 +1,290 @@
+/*
+   ldb database library
+
+   Copyright (C) Andrew Tridgell  2004
+
+     ** NOTE! The following LGPL license applies to the ldb
+     ** library. This does NOT imply that all of Samba is released
+     ** under the LGPL
+
+   This library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 3 of the License, or (at your option) any later version.
+
+   This library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with this library; if not, see <http://www.gnu.org/licenses/>.
+*/
+
+/*
+ *  Name: ldb
+ *
+ *  Component: ldb pack/unpack
+ *
+ *  Description: pack/unpack routines for ldb messages as key/value blobs
+ *
+ *  Author: Andrew Tridgell
+ */
+
+#include "ldb_tdb.h"
+
+/* change this if the data format ever changes */
+#define LTDB_PACKING_FORMAT 0x26011967
+
+/* old packing formats */
+#define LTDB_PACKING_FORMAT_NODN 0x26011966
+
+/* use a portable integer format */
+static void put_uint32(uint8_t *p, int ofs, unsigned int val)
+{
+	p += ofs;
+	p[0] = val&0xFF;
+	p[1] = (val>>8)  & 0xFF;
+	p[2] = (val>>16) & 0xFF;
+	p[3] = (val>>24) & 0xFF;
+}
+
+static unsigned int pull_uint32(uint8_t *p, int ofs)
+{
+	p += ofs;
+	return p[0] | (p[1]<<8) | (p[2]<<16) | (p[3]<<24);
+}
+
+static int attribute_storable_values(const struct ldb_message_element *el)
+{
+	if (el->num_values == 0) return 0;
+
+	if (ldb_attr_cmp(el->name, "distinguishedName") == 0) return 0;
+
+	return el->num_values;
+}
+
+/*
+  pack a ldb message into a linear buffer in a TDB_DATA
+
+  note that this routine avoids saving elements with zero values,
+  as these are equivalent to having no element
+
+  caller frees the data buffer after use
+*/
+int ltdb_pack_data(struct ldb_module *module,
+		   const struct ldb_message *message,
+		   TDB_DATA *data)
+{
+	struct ldb_context *ldb;
+	unsigned int i, j, real_elements=0;
+	size_t size;
+	const char *dn;
+	uint8_t *p;
+	size_t len;
+
+	ldb = ldb_module_get_ctx(module);
+
+	dn = ldb_dn_get_linearized(message->dn);
+	if (dn == NULL) {
+		errno = ENOMEM;
+		return -1;
+	}
+
+	/* work out how big it needs to be */
+	size = 8;
+
+	size += 1 + strlen(dn);
+
+	for (i=0;i<message->num_elements;i++) {
+		if (attribute_storable_values(&message->elements[i]) == 0) {
+			continue;
+		}
+
+		real_elements++;
+
+		size += 1 + strlen(message->elements[i].name) + 4;
+		for (j=0;j<message->elements[i].num_values;j++) {
+			size += 4 + message->elements[i].values[j].length + 1;
+		}
+	}
+
+	/* allocate it */
+	data->dptr = talloc_array(ldb, uint8_t, size);
+	if (!data->dptr) {
+		errno = ENOMEM;
+		return -1;
+	}
+	data->dsize = size;
+
+	p = data->dptr;
+	put_uint32(p, 0, LTDB_PACKING_FORMAT);
+	put_uint32(p, 4, real_elements);
+	p += 8;
+
+	/* the dn needs to be packed so we can be case preserving
+	   while hashing on a case folded dn */
+	len = strlen(dn);
+	memcpy(p, dn, len+1);
+	p += len + 1;
+
+	for (i=0;i<message->num_elements;i++) {
+		if (attribute_storable_values(&message->elements[i]) == 0) {
+			continue;
+		}
+		len = strlen(message->elements[i].name);
+		memcpy(p, message->elements[i].name, len+1);
+		p += len + 1;
+		put_uint32(p, 0, message->elements[i].num_values);
+		p += 4;
+		for (j=0;j<message->elements[i].num_values;j++) {
+			put_uint32(p, 0, message->elements[i].values[j].length);
+			memcpy(p+4, message->elements[i].values[j].data,
+			       message->elements[i].values[j].length);
+			p[4+message->elements[i].values[j].length] = 0;
+			p += 4 + message->elements[i].values[j].length + 1;
+		}
+	}
+
+	return 0;
+}
+
+/*
+  unpack a ldb message from a linear buffer in TDB_DATA
+
+  Free with ltdb_unpack_data_free()
+*/
+int ltdb_unpack_data(struct ldb_context *ldb,
+		     const TDB_DATA *data,
+		     struct ldb_message *message)
+{
+	uint8_t *p;
+	unsigned int remaining;
+	unsigned int i, j;
+	unsigned format;
+	size_t len;
+
+	message->elements = NULL;
+
+	p = data->dptr;
+	if (data->dsize < 8) {
+		errno = EIO;
+		goto failed;
+	}
+
+	format = pull_uint32(p, 0);
+	message->num_elements = pull_uint32(p, 4);
+	p += 8;
+
+	remaining = data->dsize - 8;
+
+	switch (format) {
+	case LTDB_PACKING_FORMAT_NODN:
+		message->dn = NULL;
+		break;
+
+	case LTDB_PACKING_FORMAT:
+		len = strnlen((char *)p, remaining);
+		if (len == remaining) {
+			errno = EIO;
+			goto failed;
+		}
+		message->dn = ldb_dn_new(message, ldb, (char *)p);
+		if (message->dn == NULL) {
+			errno = ENOMEM;
+			goto failed;
+		}
+		remaining -= len + 1;
+		p += len + 1;
+		break;
+
+	default:
+		errno = EIO;
+		goto failed;
+	}
+
+	if (message->num_elements == 0) {
+		return 0;
+	}
+
+	if (message->num_elements > remaining / 6) {
+		errno = EIO;
+		goto failed;
+	}
+
+	message->elements = talloc_array(message, struct ldb_message_element, message->num_elements);
+	if (!message->elements) {
+		errno = ENOMEM;
+		goto failed;
+	}
+
+	memset(message->elements, 0,
+	       message->num_elements * sizeof(struct ldb_message_element));
+
+	for (i=0;i<message->num_elements;i++) {
+		if (remaining < 10) {
+			errno = EIO;
+			goto failed;
+		}
+		len = strnlen((char *)p, remaining-6);
+		if (len == remaining-6) {
+			errno = EIO;
+			goto failed;
+		}
+		if (len == 0) {
+			errno = EIO;
+			goto failed;
+		}
+		message->elements[i].flags = 0;
+		message->elements[i].name = talloc_strndup(message->elements, (char *)p, len);
+		if (message->elements[i].name == NULL) {
+			errno = ENOMEM;
+			goto failed;
+		}
+		remaining -= len + 1;
+		p += len + 1;
+		message->elements[i].num_values = pull_uint32(p, 0);
+		message->elements[i].values = NULL;
+		if (message->elements[i].num_values != 0) {
+			message->elements[i].values = talloc_array(message->elements,
+								     struct ldb_val,
+								     message->elements[i].num_values);
+			if (!message->elements[i].values) {
+				errno = ENOMEM;
+				goto failed;
+			}
+		}
+		p += 4;
+		remaining -= 4;
+		for (j=0;j<message->elements[i].num_values;j++) {
+			len = pull_uint32(p, 0);
+			if (len > remaining-5) {
+				errno = EIO;
+				goto failed;
+			}
+
+			message->elements[i].values[j].length = len;
+			message->elements[i].values[j].data = talloc_size(message->elements[i].values, len+1);
+			if (message->elements[i].values[j].data == NULL) {
+				errno = ENOMEM;
+				goto failed;
+			}
+			memcpy(message->elements[i].values[j].data, p+4, len);
+			message->elements[i].values[j].data[len] = 0;
+
+			remaining -= len+4+1;
+			p += len+4+1;
+		}
+	}
+
+	if (remaining != 0) {
+		ldb_debug(ldb, LDB_DEBUG_ERROR,
+			  "Error: %d bytes unread in ltdb_unpack_data", remaining);
+	}
+
+	return 0;
+
+failed:
+	talloc_free(message->elements);
+	return -1;
+}