Add generic buffer code

Represents a block of memory that can be added to, parsed and so on

6 files changed, 515 insertions, 56 deletions

diff --git a/common/Makefile.am b/common/Makefile.am
index 5d38c88..ce6dd2a 100644
--- a/common/Makefile.am
+++ b/common/Makefile.am
@@ -20,6 +20,7 @@ libp11_compat_la_SOURCES = \
 libp11_library_la_SOURCES = \
 	attrs.c attrs.h \
 	array.c array.h \
+	buffer.c buffer.h \
 	debug.c debug.h \
 	dict.c dict.h \
 	library.c library.h \
diff --git a/common/buffer.c b/common/buffer.c
new file mode 100644
index 0000000..a91623e
--- /dev/null
+++ b/common/buffer.c
@@ -0,0 +1,180 @@
+/* -*- Mode: C; indent-tabs-mode: t; c-basic-offset: 8; tab-width: 8 -*- */
+/* buffer.c - Generic data buffer, used by openssh, gnome-keyring
+
+   Copyright (C) 2007, 2012 Stefan Walter
+   Copyright (C) 2013 Red Hat Inc.
+
+   The Gnome Keyring Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Library General Public License as
+   published by the Free Software Foundation; either version 2 of the
+   License, or (at your option) any later version.
+
+   The Gnome Keyring 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
+   Library General Public License for more details.
+
+   You should have received a copy of the GNU Library General Public
+   License along with the Gnome Library; see the file COPYING.LIB.  If not,
+   write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+   Boston, MA 02111-1307, USA.
+
+   Author: Stef Walter <stef@thewalter.net>
+*/
+
+#include "config.h"
+
+#include "buffer.h"
+#include "debug.h"
+
+#include <assert.h>
+#include <stdlib.h>
+#include <string.h>
+#include <stdarg.h>
+
+static bool
+buffer_realloc (p11_buffer *buffer,
+                size_t size)
+{
+	void *data;
+
+	/* Memory owned elsewhere can't be reallocated */
+	return_val_if_fail (buffer->frealloc != NULL, false);
+
+	/* Reallocate built in buffer using allocator */
+	data = (buffer->frealloc) (buffer->data, size);
+	if (!data && size > 0) {
+		p11_buffer_fail (buffer);
+		return_val_if_reached (false);
+	}
+
+	buffer->data = data;
+	buffer->size = size;
+	return true;
+}
+
+bool
+p11_buffer_init (p11_buffer *buffer,
+                 size_t reserve)
+{
+	p11_buffer_init_full (buffer, NULL, 0, 0, realloc, free);
+	return buffer_realloc (buffer, reserve);
+}
+
+bool
+p11_buffer_init_null (p11_buffer *buffer,
+                      size_t reserve)
+{
+	p11_buffer_init_full (buffer, NULL, 0, P11_BUFFER_NULL, realloc, free);
+	return buffer_realloc (buffer, reserve);
+}
+
+void
+p11_buffer_init_full (p11_buffer *buffer,
+                      void *data,
+                      size_t len,
+                      int flags,
+                      void * (* frealloc) (void *, size_t),
+                      void (* ffree) (void *))
+{
+	memset (buffer, 0, sizeof (*buffer));
+
+	buffer->data = data;
+	buffer->len = len;
+	buffer->size = len;
+	buffer->flags = flags;
+	buffer->frealloc = frealloc;
+	buffer->ffree = ffree;
+
+	return_if_fail (!(flags & P11_BUFFER_FAILED));
+}
+
+void
+p11_buffer_uninit (p11_buffer *buffer)
+{
+	return_if_fail (buffer != NULL);
+
+	if (buffer->ffree && buffer->data)
+		(buffer->ffree) (buffer->data);
+	memset (buffer, 0, sizeof (*buffer));
+}
+
+void *
+p11_buffer_steal (p11_buffer *buffer,
+                  size_t *length)
+{
+	void *data;
+
+	return_val_if_fail (p11_buffer_ok (buffer), NULL);
+
+	if (length)
+		*length = buffer->len;
+	data = buffer->data;
+
+	buffer->data = NULL;
+	buffer->size = 0;
+	buffer->len = 0;
+	return data;
+}
+
+bool
+p11_buffer_reset (p11_buffer *buffer,
+                  size_t reserve)
+{
+	buffer->flags &= ~P11_BUFFER_FAILED;
+	buffer->len = 0;
+
+	if (reserve < buffer->size)
+		return true;
+	return buffer_realloc (buffer, reserve);
+}
+
+void *
+p11_buffer_append (p11_buffer *buffer,
+                   size_t length)
+{
+	unsigned char *data;
+	size_t terminator;
+	size_t newlen;
+	size_t reserve;
+
+	return_val_if_fail (p11_buffer_ok (buffer), NULL);
+
+	terminator = (buffer->flags & P11_BUFFER_NULL) ? 1 : 0;
+	reserve = terminator + length + buffer->len;
+
+	if (reserve > buffer->size) {
+
+		/* Calculate a new length, minimize number of buffer allocations */
+		newlen = buffer->size * 2;
+		if (!newlen)
+			newlen = 16;
+		if (reserve > newlen)
+			newlen = reserve;
+
+		if (!buffer_realloc (buffer, newlen))
+			return_val_if_reached (NULL);
+	}
+
+	data = buffer->data;
+	data += buffer->len;
+	buffer->len += length;
+	if (terminator)
+		data[length] = '\0';
+	return data;
+}
+
+void
+p11_buffer_add (p11_buffer *buffer,
+                const void *data,
+                ssize_t length)
+{
+	void *at;
+
+	if (length < 0)
+		length = strlen (data);
+
+	at = p11_buffer_append (buffer, length);
+	return_if_fail (at != NULL);
+	memcpy (at, data, length);
+}
diff --git a/common/buffer.h b/common/buffer.h
new file mode 100644
index 0000000..d5335f8
--- /dev/null
+++ b/common/buffer.h
@@ -0,0 +1,82 @@
+/* -*- Mode: C; indent-tabs-mode: t; c-basic-offset: 8; tab-width: 8 -*- */
+/* buffer.h - Generic data buffer, used by openssh, gnome-keyring
+
+   Copyright (C) 2007, 2012 Stefan Walter
+   Copyright (C) 2012 Red Hat Inc.
+
+   The Gnome Keyring Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Library General Public License as
+   published by the Free Software Foundation; either version 2 of the
+   License, or (at your option) any later version.
+
+   The Gnome Keyring 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
+   Library General Public License for more details.
+
+   You should have received a copy of the GNU Library General Public
+   License along with the Gnome Library; see the file COPYING.LIB.  If not,
+   write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+   Boston, MA 02111-1307, USA.
+
+   Author: Stef Walter <stef@thewalter.net>
+*/
+
+#ifndef P11_BUFFER_H_
+#define P11_BUFFER_H_
+
+#include "compat.h"
+
+enum {
+	P11_BUFFER_FAILED = 1 << 0,
+	P11_BUFFER_NULL = 1 << 1,
+};
+
+typedef struct {
+	void *data;
+	size_t len;
+
+	int flags;
+	size_t size;
+	void * (* frealloc) (void *, size_t);
+	void (* ffree) (void *);
+} p11_buffer;
+
+bool             p11_buffer_init             (p11_buffer *buffer,
+                                              size_t size);
+
+bool             p11_buffer_init_null        (p11_buffer *buffer,
+                                              size_t size);
+
+void             p11_buffer_init_full        (p11_buffer *buffer,
+                                              void *data,
+                                              size_t len,
+                                              int flags,
+                                              void * (* frealloc) (void *, size_t),
+                                              void (* ffree) (void *));
+
+void             p11_buffer_uninit           (p11_buffer *buffer);
+
+void *           p11_buffer_steal            (p11_buffer *buffer,
+                                              size_t *length);
+
+bool             p11_buffer_reset            (p11_buffer *buffer,
+                                              size_t size);
+
+void *           p11_buffer_append           (p11_buffer *buffer,
+                                              size_t length);
+
+void             p11_buffer_add              (p11_buffer *buffer,
+                                              const void *data,
+                                              ssize_t length);
+
+#define          p11_buffer_fail(buf) \
+	((buf)->flags |= P11_BUFFER_FAILED)
+
+#define          p11_buffer_ok(buf) \
+	(((buf)->flags & P11_BUFFER_FAILED) ? false : true)
+
+#define          p11_buffer_failed(buf) \
+	(((buf)->flags & P11_BUFFER_FAILED) ? true : false)
+
+#endif /* BUFFER_H */
diff --git a/common/tests/Makefile.am b/common/tests/Makefile.am
index 4badbb5..3b6b986 100644
--- a/common/tests/Makefile.am
+++ b/common/tests/Makefile.am
@@ -21,6 +21,7 @@ CHECK_PROGS = \
 	test-dict \
 	test-array \
 	test-attrs \
+	test-buffer \
 	$(NULL)
 
 noinst_PROGRAMS = \
diff --git a/common/tests/test-buffer.c b/common/tests/test-buffer.c
new file mode 100644
index 0000000..9db5f83
--- /dev/null
+++ b/common/tests/test-buffer.c
@@ -0,0 +1,214 @@
+/*
+ * Copyright (c) 2012 Red Hat Inc.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ *     * Redistributions of source code must retain the above
+ *       copyright notice, this list of conditions and the
+ *       following disclaimer.
+ *     * Redistributions in binary form must reproduce the
+ *       above copyright notice, this list of conditions and
+ *       the following disclaimer in the documentation and/or
+ *       other materials provided with the distribution.
+ *     * The names of contributors to this software may not be
+ *       used to endorse or promote products derived from this
+ *       software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
+ * THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
+ * DAMAGE.
+ *
+ * Author: Stef Walter <stef@thewalter.net>
+ */
+
+#include "config.h"
+#include "CuTest.h"
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+
+#include "debug.h"
+#include "buffer.h"
+
+static void
+test_init_uninit (CuTest *tc)
+{
+	p11_buffer buffer;
+
+	p11_buffer_init (&buffer, 10);
+	CuAssertPtrNotNull (tc, buffer.data);
+	CuAssertIntEquals (tc, 0, buffer.len);
+	CuAssertIntEquals (tc, 0, buffer.flags);
+	CuAssertTrue (tc, buffer.size >= 10);
+	CuAssertPtrNotNull (tc, buffer.ffree);
+	CuAssertPtrNotNull (tc, buffer.frealloc);
+
+	p11_buffer_uninit (&buffer);
+}
+
+static void
+test_append (CuTest *tc)
+{
+	p11_buffer buffer;
+
+	p11_buffer_init (&buffer, 10);
+	buffer.len = 5;
+	p11_buffer_append (&buffer, 35);
+	CuAssertIntEquals (tc, 5 + 35, buffer.len);
+	CuAssertTrue (tc, buffer.size >= 35 + 5);
+
+	p11_buffer_append (&buffer, 15);
+	CuAssertIntEquals (tc, 5 + 35 + 15, buffer.len);
+	CuAssertTrue (tc, buffer.size >= 5 + 35 + 15);
+
+	p11_buffer_uninit (&buffer);
+}
+
+static void
+test_null (CuTest *tc)
+{
+	p11_buffer buffer;
+
+	p11_buffer_init_null (&buffer, 10);
+	p11_buffer_add (&buffer, "Blah", -1);
+	p11_buffer_add (&buffer, " blah", -1);
+
+	CuAssertStrEquals (tc, "Blah blah", buffer.data);
+
+	p11_buffer_uninit (&buffer);
+}
+
+static int mock_realloced = 0;
+static int mock_freed = 0;
+
+static void *
+mock_realloc (void *data,
+              size_t size)
+{
+	mock_realloced++;
+	return realloc (data, size);
+}
+
+static void
+mock_free (void *data)
+{
+	mock_freed++;
+	free (data);
+}
+
+static void
+test_init_for_data (CuTest *tc)
+{
+	p11_buffer buffer;
+	unsigned char *ret;
+	size_t len;
+
+	mock_realloced = 0;
+	mock_freed = 0;
+
+	p11_buffer_init_full (&buffer, (unsigned char *)strdup ("blah"), 4, 0,
+	                       mock_realloc, mock_free);
+
+	CuAssertPtrNotNull (tc, buffer.data);
+	CuAssertStrEquals (tc, "blah", (char *)buffer.data);
+	CuAssertIntEquals (tc, 4, buffer.len);
+	CuAssertIntEquals (tc, 0, buffer.flags);
+	CuAssertIntEquals (tc, 4, buffer.size);
+	CuAssertPtrEquals (tc, mock_free, buffer.ffree);
+	CuAssertPtrEquals (tc, mock_realloc, buffer.frealloc);
+
+	CuAssertIntEquals (tc, 0, mock_realloced);
+	CuAssertIntEquals (tc, 0, mock_freed);
+
+	len = buffer.len;
+	ret = p11_buffer_append (&buffer, 1024);
+	CuAssertPtrEquals (tc, (char *)buffer.data + len, ret);
+	CuAssertIntEquals (tc, 1, mock_realloced);
+
+	p11_buffer_uninit (&buffer);
+	CuAssertIntEquals (tc, 1, mock_realloced);
+	CuAssertIntEquals (tc, 1, mock_freed);
+}
+
+static void
+test_steal (CuTest *tc)
+{
+	p11_buffer buffer;
+	char *string;
+	size_t length;
+
+	mock_freed = 0;
+
+	p11_buffer_init_full (&buffer, (unsigned char *)strdup ("blah"), 4,
+	                      P11_BUFFER_NULL, mock_realloc, mock_free);
+
+	CuAssertPtrNotNull (tc, buffer.data);
+	CuAssertStrEquals (tc, "blah", buffer.data);
+
+	p11_buffer_add (&buffer, " yada", -1);
+	CuAssertStrEquals (tc, "blah yada", buffer.data);
+
+	string = p11_buffer_steal (&buffer, &length);
+	p11_buffer_uninit (&buffer);
+
+	CuAssertStrEquals (tc, "blah yada", string);
+	CuAssertIntEquals (tc, 9, length);
+	CuAssertIntEquals (tc, 0, mock_freed);
+
+	free (string);
+}
+
+static void
+test_add (CuTest *tc)
+{
+	p11_buffer buffer;
+
+	p11_buffer_init (&buffer, 10);
+
+	p11_buffer_add (&buffer, (unsigned char *)"Planet Express", 15);
+	CuAssertIntEquals (tc, 15, buffer.len);
+	CuAssertStrEquals (tc, "Planet Express", (char *)buffer.data);
+	CuAssertTrue (tc, p11_buffer_ok (&buffer));
+
+	p11_buffer_uninit (&buffer);
+}
+
+int
+main (void)
+{
+	CuString *output = CuStringNew ();
+	CuSuite* suite = CuSuiteNew ();
+	int ret;
+
+	setenv ("P11_KIT_STRICT", "1", 1);
+	p11_debug_init ();
+
+	SUITE_ADD_TEST (suite, test_init_uninit);
+	SUITE_ADD_TEST (suite, test_init_for_data);
+	SUITE_ADD_TEST (suite, test_append);
+	SUITE_ADD_TEST (suite, test_null);
+	SUITE_ADD_TEST (suite, test_add);
+	SUITE_ADD_TEST (suite, test_steal);
+
+	CuSuiteRun (suite);
+	CuSuiteSummary (suite, output);
+	CuSuiteDetails (suite, output);
+	printf ("%s\n", output->buffer);
+	ret = suite->failCount;
+	CuSuiteDelete (suite);
+	CuStringDelete (output);
+
+	return ret;
+}
diff --git a/p11-kit/uri.c b/p11-kit/uri.c
index 9678358..8b16e46 100644
--- a/p11-kit/uri.c
+++ b/p11-kit/uri.c
@@ -35,6 +35,7 @@
 #include "config.h"
 
 #include "attrs.h"
+#include "buffer.h"
 #define P11_DEBUG_FLAG P11_DEBUG_URI
 #include "debug.h"
 #include "library.h"
@@ -704,41 +705,27 @@ p11_kit_uri_new (void)
 }
 
 static bool
-format_raw_string (char **string,
-                   size_t *length,
+format_raw_string (p11_buffer *buffer,
                    bool *is_first,
                    const char *name,
                    const char *value)
 {
-	size_t namelen;
-	size_t vallen;
-
 	/* Not set */
 	if (!value)
 		return true;
 
-	namelen = strlen (name);
-	vallen = strlen (value);
-
-	*string = realloc (*string, *length + namelen + vallen + 3);
-	return_val_if_fail (*string != NULL, false);
-
 	if (!*is_first)
-		(*string)[(*length)++] = ';';
-	memcpy ((*string) + *length, name, namelen);
-	*length += namelen;
-	(*string)[(*length)++] = '=';
-	memcpy ((*string) + *length, value, vallen);
-	*length += vallen;
-	(*string)[*length] = 0;
+		p11_buffer_add (buffer, ";", 1);
+	p11_buffer_add (buffer, name, -1);
+	p11_buffer_add (buffer, "=", 1);
+	p11_buffer_add (buffer, value, -1);
 	*is_first = false;
 
-	return true;
+	return p11_buffer_ok (buffer);
 }
 
 static bool
-format_encode_string (char **string,
-                      size_t *length,
+format_encode_string (p11_buffer *buffer,
                       bool *is_first,
                       const char *name,
                       const unsigned char *value,
@@ -751,15 +738,14 @@ format_encode_string (char **string,
 	encoded = url_encode (value, value + n_value, NULL, force);
 	return_val_if_fail (encoded != NULL, false);
 
-	ret = format_raw_string (string, length, is_first, name, encoded);
+	ret = format_raw_string (buffer, is_first, name, encoded);
 	free (encoded);
 	return ret;
 }
 
 
 static bool
-format_struct_string (char **string,
-                      size_t *length,
+format_struct_string (p11_buffer *buffer,
                       bool *is_first,
                       const char *name,
                       const unsigned char *value,
@@ -772,12 +758,11 @@ format_struct_string (char **string,
 		return true;
 
 	len = p11_kit_space_strlen (value, value_max);
-	return format_encode_string (string, length, is_first, name, value, len, false);
+	return format_encode_string (buffer, is_first, name, value, len, false);
 }
 
 static bool
-format_attribute_string (char **string,
-                         size_t *length,
+format_attribute_string (p11_buffer *buffer,
                          bool *is_first,
                          const char *name,
                          CK_ATTRIBUTE_PTR attr,
@@ -787,14 +772,13 @@ format_attribute_string (char **string,
 	if (attr == NULL)
 		return true;
 
-	return format_encode_string (string, length, is_first, name,
+	return format_encode_string (buffer, is_first, name,
 	                             attr->pValue, attr->ulValueLen,
 	                             force);
 }
 
 static bool
-format_attribute_class (char **string,
-                        size_t *length,
+format_attribute_class (p11_buffer *buffer,
                         bool *is_first,
                         const char *name,
                         CK_ATTRIBUTE_PTR attr)
@@ -827,25 +811,24 @@ format_attribute_class (char **string,
 		return true;
 	}
 
-	return format_raw_string (string, length, is_first, name, value);
+	return format_raw_string (buffer, is_first, name, value);
 }
 
 static bool
-format_struct_version (char **string,
-                       size_t *length,
+format_struct_version (p11_buffer *buffer,
                        bool *is_first,
                        const char *name,
                        CK_VERSION_PTR version)
 {
-	char buffer[64];
+	char buf[64];
 
 	/* Not set */
 	if (version->major == (CK_BYTE)-1 && version->minor == (CK_BYTE)-1)
 		return true;
 
-	snprintf (buffer, sizeof (buffer), "%d.%d",
+	snprintf (buf, sizeof (buf), "%d.%d",
 	          (int)version->major, (int)version->minor);
-	return format_raw_string (string, length, is_first, name, buffer);
+	return format_raw_string (buffer, is_first, name, buf);
 }
 
 /**
@@ -879,26 +862,23 @@ format_struct_version (char **string,
 int
 p11_kit_uri_format (P11KitUri *uri, P11KitUriType uri_type, char **string)
 {
-	char *result = NULL;
-	size_t length = 0;
+	p11_buffer buffer;
 	bool is_first = true;
 
 	return_val_if_fail (uri != NULL, P11_KIT_URI_UNEXPECTED);
 	return_val_if_fail (string != NULL, P11_KIT_URI_UNEXPECTED);
 
-	result = malloc (128);
-	return_val_if_fail (result != NULL, P11_KIT_URI_UNEXPECTED);
+	if (!p11_buffer_init_null (&buffer, 64))
+		return_val_if_reached (P11_KIT_URI_UNEXPECTED);
 
-	length = P11_KIT_URI_SCHEME_LEN;
-	memcpy (result, P11_KIT_URI_SCHEME, length);
-	result[length] = ':';
-	result[++length] = 0;
+	p11_buffer_add (&buffer, P11_KIT_URI_SCHEME, P11_KIT_URI_SCHEME_LEN);
+	p11_buffer_add (&buffer, ":", 1);
 
 	if ((uri_type & P11_KIT_URI_FOR_MODULE) == P11_KIT_URI_FOR_MODULE) {
-		if (!format_struct_string (&result, &length, &is_first, "library-description",
+		if (!format_struct_string (&buffer, &is_first, "library-description",
 		                           uri->module.libraryDescription,
 		                           sizeof (uri->module.libraryDescription)) ||
-		    !format_struct_string (&result, &length, &is_first, "library-manufacturer",
+		    !format_struct_string (&buffer, &is_first, "library-manufacturer",
 		                           uri->module.manufacturerID,
 		                           sizeof (uri->module.manufacturerID))) {
 			return_val_if_reached (P11_KIT_URI_UNEXPECTED);
@@ -906,23 +886,23 @@ p11_kit_uri_format (P11KitUri *uri, P11KitUriType uri_type, char **string)
 	}
 
 	if ((uri_type & P11_KIT_URI_FOR_MODULE_WITH_VERSION) == P11_KIT_URI_FOR_MODULE_WITH_VERSION) {
-		if (!format_struct_version (&result, &length, &is_first, "library-version",
+		if (!format_struct_version (&buffer, &is_first, "library-version",
 		                            &uri->module.libraryVersion)) {
 			return_val_if_reached (P11_KIT_URI_UNEXPECTED);
 		}
 	}
 
 	if ((uri_type & P11_KIT_URI_FOR_TOKEN) == P11_KIT_URI_FOR_TOKEN) {
-		if (!format_struct_string (&result, &length, &is_first, "model",
+		if (!format_struct_string (&buffer, &is_first, "model",
 		                           uri->token.model,
 		                           sizeof (uri->token.model)) ||
-		    !format_struct_string (&result, &length, &is_first, "manufacturer",
+		    !format_struct_string (&buffer, &is_first, "manufacturer",
 		                           uri->token.manufacturerID,
 		                           sizeof (uri->token.manufacturerID)) ||
-		    !format_struct_string (&result, &length, &is_first, "serial",
+		    !format_struct_string (&buffer, &is_first, "serial",
 		                           uri->token.serialNumber,
 		                           sizeof (uri->token.serialNumber)) ||
-		    !format_struct_string (&result, &length, &is_first, "token",
+		    !format_struct_string (&buffer, &is_first, "token",
 		                           uri->token.label,
 		                           sizeof (uri->token.label))) {
 			return_val_if_reached (P11_KIT_URI_UNEXPECTED);
@@ -930,30 +910,31 @@ p11_kit_uri_format (P11KitUri *uri, P11KitUriType uri_type, char **string)
 	}
 
 	if ((uri_type & P11_KIT_URI_FOR_OBJECT) == P11_KIT_URI_FOR_OBJECT) {
-		if (!format_attribute_string (&result, &length, &is_first, "id",
+		if (!format_attribute_string (&buffer, &is_first, "id",
 		                              p11_kit_uri_get_attribute (uri, CKA_ID),
 		                              true) ||
-		    !format_attribute_string (&result, &length, &is_first, "object",
+		    !format_attribute_string (&buffer, &is_first, "object",
 		                              p11_kit_uri_get_attribute (uri, CKA_LABEL),
 		                              false)) {
 			return_val_if_reached (P11_KIT_URI_UNEXPECTED);
 		}
 
-		if (!format_attribute_class (&result, &length, &is_first, "object-type",
+		if (!format_attribute_class (&buffer, &is_first, "object-type",
 		                             p11_kit_uri_get_attribute (uri, CKA_CLASS))) {
 			return_val_if_reached (P11_KIT_URI_UNEXPECTED);
 		}
 	}
 
 	if (uri->pin_source) {
-		if (!format_encode_string (&result, &length, &is_first, "pin-source",
+		if (!format_encode_string (&buffer, &is_first, "pin-source",
 		                           (const unsigned char*)uri->pin_source,
 		                           strlen (uri->pin_source), 0)) {
 			return_val_if_reached (P11_KIT_URI_UNEXPECTED);
 		}
 	}
 
-	*string = result;
+	return_val_if_fail (p11_buffer_ok (&buffer), P11_KIT_URI_UNEXPECTED);
+	*string = p11_buffer_steal (&buffer, NULL);
 	return P11_KIT_URI_OK;
 }