server/util_xml.c - httpd - Git at Google

 /*
 ** Copyright (C) 1998-2000 Greg Stein. All Rights Reserved.
 **
 ** By using this file, you agree to the terms and conditions set forth in
 ** the LICENSE.html file which can be found at the top level of the mod_dav
 ** distribution or at http://www.webdav.org/mod_dav/license-1.html.
 **
 ** Contact information:
 **   Greg Stein, PO Box 760, Palo Alto, CA, 94302
 **   gstein@lyra.org, http://www.webdav.org/mod_dav/
 */

 /*
 ** DAV extension module for Apache 1.3.*
 **  - XML parser for the body of a request
 **
 ** Written by Greg Stein, gstein@lyra.org, http://www.lyra.org/
 */

 /* James Clark's Expat parser */
 #include <xmlparse.h>

 #include "httpd.h"
 #include "http_protocol.h"
 #include "http_log.h"

 #include "mod_dav.h"


 /* errors related to namespace processing */
 #define DAV_NS_ERROR_UNKNOWN_PREFIX	(DAV_NS_ERROR_BASE)

 /* test for a namespace prefix that begins with [Xx][Mm][Ll] */
 #define DAV_NS_IS_RESERVED(name) \
 	( (name[0] == 'X' || name[0] == 'x') && \
 	  (name[1] == 'M' || name[1] == 'm') && \
 	  (name[2] == 'L' || name[2] == 'l') )

 /* content for parsing */
 typedef struct dav_xml_ctx {
     dav_xml_doc *doc;		/* the doc we're parsing */
     ap_pool *p;			/* the pool we allocate from */
     dav_xml_elem *cur_elem;	/* current element */

     int error;			/* an error has occurred */
     /* errors may be DAV_NS_ERROR_* or other errors defined here (none yet) */

 } dav_xml_ctx;

 /* struct for scoping namespace declarations */
 typedef struct dav_xml_ns_scope {
     const char *prefix;		/* prefix used for this ns */
     int ns;			/* index into namespace table */
     int emptyURI;		/* the namespace URI is the empty string */
     struct dav_xml_ns_scope *next;	/* next scoped namespace */
 } dav_xml_ns_scope;

 /* ### need a similar mechanism for xml:lang values */


 /* return namespace table index for a given prefix */
 static int dav_find_prefix(dav_xml_ctx *ctx, const char *prefix)
 {
     dav_xml_elem *elem = ctx->cur_elem;

     /*
     ** Walk up the tree, looking for a namespace scope that defines this
     ** prefix.
     */
     for (; elem; elem = elem->parent) {
 	dav_xml_ns_scope *ns_scope = elem->ns_scope;

 	for (ns_scope = elem->ns_scope; ns_scope; ns_scope = ns_scope->next) {
 	    if (strcmp(prefix, ns_scope->prefix) == 0) {
 		if (ns_scope->emptyURI) {
 		    /*
 		    ** It is possible to set the default namespace to an
 		    ** empty URI string; this resets the default namespace
 		    ** to mean "no namespace." We just found the prefix
 		    ** refers to an empty URI, so return "no namespace."
 		    */
 		    return DAV_NS_NONE;
 		}

 		return ns_scope->ns;
 	    }
 	}
     }

     /*
      * If the prefix is empty (""), this means that a prefix was not
      * specified in the element/attribute. The search that was performed
      * just above did not locate a default namespace URI (which is stored
      * into ns_scope with an empty prefix). This means the element/attribute
      * has "no namespace". We have a reserved value for this.
      */
     if (*prefix == '\0') {
 	return DAV_NS_NONE;
     }

     /* not found */
     return DAV_NS_ERROR_UNKNOWN_PREFIX;
 }

 static void dav_start_handler(void *userdata, const char *name, const char **attrs)
 {
     dav_xml_ctx *ctx = userdata;
     dav_xml_elem *elem;
     dav_xml_attr *attr;
     dav_xml_attr *prev;
     char *colon;
     const char *quoted;

     /* punt once we find an error */
     if (ctx->error)
 	return;

     elem = ap_pcalloc(ctx->p, sizeof(*elem));

     /* prep the element */
     elem->name = ap_pstrdup(ctx->p, name);

     /* fill in the attributes (note: ends up in reverse order) */
     while (*attrs) {
 	attr = ap_palloc(ctx->p, sizeof(*attr));
 	attr->name = ap_pstrdup(ctx->p, *attrs++);
 	attr->value = ap_pstrdup(ctx->p, *attrs++);
 	attr->next = elem->attr;
 	elem->attr = attr;
     }

     /* hook the element into the tree */
     if (ctx->cur_elem == NULL) {
 	/* no current element; this also becomes the root */
 	ctx->cur_elem = ctx->doc->root = elem;
     }
     else {
 	/* this element appeared within the current elem */
 	elem->parent = ctx->cur_elem;

 	/* set up the child/sibling links */
 	if (elem->parent->last_child == NULL) {
 	    /* no first child either */
 	    elem->parent->first_child = elem->parent->last_child = elem;
 	}
 	else {
 	    /* hook onto the end of the parent's children */
 	    elem->parent->last_child->next = elem;
 	    elem->parent->last_child = elem;
 	}

 	/* this element is now the current element */
 	ctx->cur_elem = elem;
     }

     /* scan the attributes for namespace declarations */
     for (prev = NULL, attr = elem->attr;
 	 attr;
 	 attr = attr->next) {
 	if (strncmp(attr->name, "xmlns", 5) == 0) {
 	    const char *prefix = &attr->name[5];
 	    dav_xml_ns_scope *ns_scope;

 	    /* test for xmlns:foo= form and xmlns= form */
 	    if (*prefix == ':')
 		++prefix;
 	    else if (*prefix != '\0') {
 		/* advance "prev" since "attr" is still present */
 		prev = attr;
 		continue;
 	    }

 	    /* quote the URI before we ever start working with it */
 	    quoted = dav_quote_string(ctx->p, attr->value, 1);

 	    /* build and insert the new scope */
 	    ns_scope = ap_pcalloc(ctx->p, sizeof(*ns_scope));
 	    ns_scope->prefix = prefix;
 	    ns_scope->ns = dav_insert_uri(ctx->doc->namespaces, quoted);
 	    ns_scope->emptyURI = *quoted == '\0';
 	    ns_scope->next = elem->ns_scope;
 	    elem->ns_scope = ns_scope;

 	    /* remove this attribute from the element */
 	    if (prev == NULL)
 		elem->attr = attr->next;
 	    else
 		prev->next = attr->next;

 	    /* Note: prev will not be advanced since we just removed "attr" */
 	}
 	else if (strcmp(attr->name, "xml:lang") == 0) {
 	    /* save away the language (in quoted form) */
 	    elem->lang = dav_quote_string(ctx->p, attr->value, 1);

 	    /* remove this attribute from the element */
 	    if (prev == NULL)
 		elem->attr = attr->next;
 	    else
 		prev->next = attr->next;

 	    /* Note: prev will not be advanced since we just removed "attr" */
 	}
 	else {
 	    /* advance "prev" since "attr" is still present */
 	    prev = attr;
 	}
     }

     /*
     ** If an xml:lang attribute didn't exist (lang==NULL), then copy the
     ** language from the parent element (if present).
     **
     ** NOTE: dav_elem_size() *depends* upon this pointer equality.
     */
     if (elem->lang == NULL && elem->parent != NULL)
 	elem->lang = elem->parent->lang;

     /* adjust the element's namespace */
     colon = strchr(elem->name, ':');
     if (colon == NULL) {
 	/*
 	 * The element is using the default namespace, which will always
 	 * be found. Either it will be "no namespace", or a default
 	 * namespace URI has been specified at some point.
 	 */
 	elem->ns = dav_find_prefix(ctx, "");
     }
     else if (DAV_NS_IS_RESERVED(elem->name)) {
 	elem->ns = DAV_NS_NONE;
     }
     else {
 	*colon = '\0';
 	elem->ns = dav_find_prefix(ctx, elem->name);
 	elem->name = colon + 1;

 	if (DAV_NS_IS_ERROR(elem->ns)) {
 	    ctx->error = elem->ns;
 	    return;
 	}
     }

     /* adjust all remaining attributes' namespaces */
     for (attr = elem->attr; attr; attr = attr->next) {
 	colon = strchr(attr->name, ':');
 	if (colon == NULL) {
 	    /*
 	     * Attributes do NOT use the default namespace. Therefore,
 	     * we place them into the "no namespace" category.
 	     */
 	    attr->ns = DAV_NS_NONE;
 	}
 	else if (DAV_NS_IS_RESERVED(attr->name)) {
 	    attr->ns = DAV_NS_NONE;
 	}
 	else {
 	    *colon = '\0';
 	    attr->ns = dav_find_prefix(ctx, attr->name);
 	    attr->name = colon + 1;

 	    if (DAV_NS_IS_ERROR(attr->ns)) {
 		ctx->error = attr->ns;
 		return;
 	    }
 	}
     }
 }

 static void dav_end_handler(void *userdata, const char *name)
 {
     dav_xml_ctx *ctx = userdata;

     /* punt once we find an error */
     if (ctx->error)
 	return;

     /* pop up one level */
     ctx->cur_elem = ctx->cur_elem->parent;
 }

 static void dav_cdata_handler(void *userdata, const char *data, int len)
 {
     dav_xml_ctx *ctx = userdata;
     dav_xml_elem *elem;
     dav_text_header *hdr;
     const char *s;

     /* punt once we find an error */
     if (ctx->error)
 	return;

     elem = ctx->cur_elem;
     s = ap_pstrndup(ctx->p, data, len);

     if (elem->last_child == NULL) {
 	/* no children yet. this cdata follows the start tag */
 	hdr = &elem->first_cdata;
     }
     else {
 	/* child elements exist. this cdata follows the last child. */
 	hdr = &elem->last_child->following_cdata;
     }

     dav_text_append(ctx->p, hdr, s);
 }

 int dav_parse_input(request_rec * r, dav_xml_doc **pdoc)
 {
     int result;
     dav_xml_ctx ctx =
     {0};
     XML_Parser parser;

     if ((result = ap_setup_client_block(r, REQUEST_CHUNKED_DECHUNK)) != OK)
 	return result;

     if (r->remaining == 0) {
 	*pdoc = NULL;
 	return OK;
     }

     ctx.p = r->pool;
     ctx.doc = ap_pcalloc(ctx.p, sizeof(*ctx.doc));

     ctx.doc->namespaces = ap_make_array(ctx.p, 5, sizeof(const char *));
     dav_insert_uri(ctx.doc->namespaces, "DAV:");

     /* ### we should get the encoding from Content-Encoding */
     parser = XML_ParserCreate(NULL);
     if (parser == NULL) {
 	/* ### anything better to do? */
 	fprintf(stderr, "Ouch!  XML_ParserCreate() failed!\n");
 	exit(1);
     }

     XML_SetUserData(parser, (void *) &ctx);
     XML_SetElementHandler(parser, dav_start_handler, dav_end_handler);
     XML_SetCharacterDataHandler(parser, dav_cdata_handler);

     if (ap_should_client_block(r)) {
 	long len;
 	char *buffer;
 	char end;
 	int rv;
 	size_t total_read = 0;
 	size_t limit_xml_body = dav_get_limit_xml_body(r);

 	/* allocate our working buffer */
 	buffer = ap_palloc(r->pool, DAV_READ_BLOCKSIZE);

 	/* read the body, stuffing it into the parser */
 	while ((len = ap_get_client_block(r, buffer, DAV_READ_BLOCKSIZE)) > 0) {
 	    total_read += len;
 	    if (limit_xml_body && total_read > limit_xml_body) {
 		ap_log_rerror(APLOG_MARK, APLOG_NOERRNO | APLOG_ERR, r,
 			      "XML request body is larger than the configured "
 			      "limit of %lu", (unsigned long)limit_xml_body);
 		goto read_error;
 	    }

 	    rv = XML_Parse(parser, buffer, len, 0);
 	    if (rv == 0)
 		goto parser_error;
 	}
 	if (len == -1) {
 	    /* ap_get_client_block() has logged an error */
 	    goto read_error;
 	}

 	/* tell the parser that we're done */
 	rv = XML_Parse(parser, &end, 0, 1);
 	if (rv == 0)
 	    goto parser_error;
     }

     XML_ParserFree(parser);

     if (ctx.error) {
 	switch (ctx.error) {
 	case DAV_NS_ERROR_UNKNOWN_PREFIX:
 	    ap_log_rerror(APLOG_MARK, APLOG_ERR | APLOG_NOERRNO, r,
 			  "An undefined namespace prefix was used.");
 	    break;

 	default:
 	    ap_log_rerror(APLOG_MARK, APLOG_ERR | APLOG_NOERRNO, r,
 			  "There was an error within the XML request body.");
 	    break;
 	}

 	/* Apache will supply a default error, plus the error log above. */
 	return HTTP_BAD_REQUEST;
     }

     /* ### assert: ctx.cur_elem == NULL */

     *pdoc = ctx.doc;

     return OK;

   parser_error:
     {
 	enum XML_Error err = XML_GetErrorCode(parser);

 	/* ### fix this error message (default vs special) */
 	ap_log_rerror(APLOG_MARK, APLOG_ERR | APLOG_NOERRNO, r,
 		      "XML parser error code: %s (%d).",
 		      XML_ErrorString(err), err);

 	XML_ParserFree(parser);

 	/* Apache will supply a default error, plus the error log above. */
 	return HTTP_BAD_REQUEST;
     }

   read_error:
     XML_ParserFree(parser);

     /* Apache will supply a default error, plus whatever was logged. */
     return HTTP_BAD_REQUEST;
 }
	/*
	** Copyright (C) 1998-2000 Greg Stein. All Rights Reserved.
	**
	** By using this file, you agree to the terms and conditions set forth in
	** the LICENSE.html file which can be found at the top level of the mod_dav
	** distribution or at http://www.webdav.org/mod_dav/license-1.html.
	**
	** Contact information:
	** Greg Stein, PO Box 760, Palo Alto, CA, 94302
	** gstein@lyra.org, http://www.webdav.org/mod_dav/
	*/

	/*
	** DAV extension module for Apache 1.3.*
	** - XML parser for the body of a request
	**
	** Written by Greg Stein, gstein@lyra.org, http://www.lyra.org/
	*/

	/* James Clark's Expat parser */
	#include <xmlparse.h>

	#include "httpd.h"
	#include "http_protocol.h"
	#include "http_log.h"

	#include "mod_dav.h"


	/* errors related to namespace processing */
	#define DAV_NS_ERROR_UNKNOWN_PREFIX (DAV_NS_ERROR_BASE)

	/* test for a namespace prefix that begins with [Xx][Mm][Ll] */
	#define DAV_NS_IS_RESERVED(name) \
	( (name[0] == 'X' \|\| name[0] == 'x') && \
	(name[1] == 'M' \|\| name[1] == 'm') && \
	(name[2] == 'L' \|\| name[2] == 'l') )

	/* content for parsing */
	typedef struct dav_xml_ctx {
	dav_xml_doc doc; / the doc we're parsing */
	ap_pool p; / the pool we allocate from */
	dav_xml_elem cur_elem; / current element */

	int error; /* an error has occurred */
	/* errors may be DAV_NS_ERROR_* or other errors defined here (none yet) */

	} dav_xml_ctx;

	/* struct for scoping namespace declarations */
	typedef struct dav_xml_ns_scope {
	const char prefix; / prefix used for this ns */
	int ns; /* index into namespace table */
	int emptyURI; /* the namespace URI is the empty string */
	struct dav_xml_ns_scope next; / next scoped namespace */
	} dav_xml_ns_scope;

	/* ### need a similar mechanism for xml:lang values */


	/* return namespace table index for a given prefix */
	static int dav_find_prefix(dav_xml_ctx ctx, const char prefix)
	{
	dav_xml_elem *elem = ctx->cur_elem;

	/*
	** Walk up the tree, looking for a namespace scope that defines this
	** prefix.
	*/
	for (; elem; elem = elem->parent) {
	dav_xml_ns_scope *ns_scope = elem->ns_scope;

	for (ns_scope = elem->ns_scope; ns_scope; ns_scope = ns_scope->next) {
	if (strcmp(prefix, ns_scope->prefix) == 0) {
	if (ns_scope->emptyURI) {
	/*
	** It is possible to set the default namespace to an
	** empty URI string; this resets the default namespace
	** to mean "no namespace." We just found the prefix
	** refers to an empty URI, so return "no namespace."
	*/
	return DAV_NS_NONE;
	}

	return ns_scope->ns;
	}
	}
	}

	/*
	* If the prefix is empty (""), this means that a prefix was not
	* specified in the element/attribute. The search that was performed
	* just above did not locate a default namespace URI (which is stored
	* into ns_scope with an empty prefix). This means the element/attribute
	* has "no namespace". We have a reserved value for this.
	*/
	if (*prefix == '\0') {
	return DAV_NS_NONE;
	}

	/* not found */
	return DAV_NS_ERROR_UNKNOWN_PREFIX;
	}

	static void dav_start_handler(void userdata, const char name, const char **attrs)
	{
	dav_xml_ctx *ctx = userdata;
	dav_xml_elem *elem;
	dav_xml_attr *attr;
	dav_xml_attr *prev;
	char *colon;
	const char *quoted;

	/* punt once we find an error */
	if (ctx->error)
	return;

	elem = ap_pcalloc(ctx->p, sizeof(*elem));

	/* prep the element */
	elem->name = ap_pstrdup(ctx->p, name);

	/* fill in the attributes (note: ends up in reverse order) */
	while (*attrs) {
	attr = ap_palloc(ctx->p, sizeof(*attr));
	attr->name = ap_pstrdup(ctx->p, *attrs++);
	attr->value = ap_pstrdup(ctx->p, *attrs++);
	attr->next = elem->attr;
	elem->attr = attr;
	}

	/* hook the element into the tree */
	if (ctx->cur_elem == NULL) {
	/* no current element; this also becomes the root */
	ctx->cur_elem = ctx->doc->root = elem;
	}
	else {
	/* this element appeared within the current elem */
	elem->parent = ctx->cur_elem;

	/* set up the child/sibling links */
	if (elem->parent->last_child == NULL) {
	/* no first child either */
	elem->parent->first_child = elem->parent->last_child = elem;
	}
	else {
	/* hook onto the end of the parent's children */
	elem->parent->last_child->next = elem;
	elem->parent->last_child = elem;
	}

	/* this element is now the current element */
	ctx->cur_elem = elem;
	}

	/* scan the attributes for namespace declarations */
	for (prev = NULL, attr = elem->attr;
	attr;
	attr = attr->next) {
	if (strncmp(attr->name, "xmlns", 5) == 0) {
	const char *prefix = &attr->name[5];
	dav_xml_ns_scope *ns_scope;

	/* test for xmlns:foo= form and xmlns= form */
	if (*prefix == ':')
	++prefix;
	else if (*prefix != '\0') {
	/* advance "prev" since "attr" is still present */
	prev = attr;
	continue;
	}

	/* quote the URI before we ever start working with it */
	quoted = dav_quote_string(ctx->p, attr->value, 1);

	/* build and insert the new scope */
	ns_scope = ap_pcalloc(ctx->p, sizeof(*ns_scope));
	ns_scope->prefix = prefix;
	ns_scope->ns = dav_insert_uri(ctx->doc->namespaces, quoted);
	ns_scope->emptyURI = *quoted == '\0';
	ns_scope->next = elem->ns_scope;
	elem->ns_scope = ns_scope;

	/* remove this attribute from the element */
	if (prev == NULL)
	elem->attr = attr->next;
	else
	prev->next = attr->next;

	/* Note: prev will not be advanced since we just removed "attr" */
	}
	else if (strcmp(attr->name, "xml:lang") == 0) {
	/* save away the language (in quoted form) */
	elem->lang = dav_quote_string(ctx->p, attr->value, 1);

	/* remove this attribute from the element */
	if (prev == NULL)
	elem->attr = attr->next;
	else
	prev->next = attr->next;

	/* Note: prev will not be advanced since we just removed "attr" */
	}
	else {
	/* advance "prev" since "attr" is still present */
	prev = attr;
	}
	}

	/*
	** If an xml:lang attribute didn't exist (lang==NULL), then copy the
	** language from the parent element (if present).
	**
	** NOTE: dav_elem_size() depends upon this pointer equality.
	*/
	if (elem->lang == NULL && elem->parent != NULL)
	elem->lang = elem->parent->lang;

	/* adjust the element's namespace */
	colon = strchr(elem->name, ':');
	if (colon == NULL) {
	/*
	* The element is using the default namespace, which will always
	* be found. Either it will be "no namespace", or a default
	* namespace URI has been specified at some point.
	*/
	elem->ns = dav_find_prefix(ctx, "");
	}
	else if (DAV_NS_IS_RESERVED(elem->name)) {
	elem->ns = DAV_NS_NONE;
	}
	else {
	*colon = '\0';
	elem->ns = dav_find_prefix(ctx, elem->name);
	elem->name = colon + 1;

	if (DAV_NS_IS_ERROR(elem->ns)) {
	ctx->error = elem->ns;
	return;
	}
	}

	/* adjust all remaining attributes' namespaces */
	for (attr = elem->attr; attr; attr = attr->next) {
	colon = strchr(attr->name, ':');
	if (colon == NULL) {
	/*
	* Attributes do NOT use the default namespace. Therefore,
	* we place them into the "no namespace" category.
	*/
	attr->ns = DAV_NS_NONE;
	}
	else if (DAV_NS_IS_RESERVED(attr->name)) {
	attr->ns = DAV_NS_NONE;
	}
	else {
	*colon = '\0';
	attr->ns = dav_find_prefix(ctx, attr->name);
	attr->name = colon + 1;

	if (DAV_NS_IS_ERROR(attr->ns)) {
	ctx->error = attr->ns;
	return;
	}
	}
	}
	}

	static void dav_end_handler(void userdata, const char name)
	{
	dav_xml_ctx *ctx = userdata;

	/* punt once we find an error */
	if (ctx->error)
	return;

	/* pop up one level */
	ctx->cur_elem = ctx->cur_elem->parent;
	}

	static void dav_cdata_handler(void userdata, const char data, int len)
	{
	dav_xml_ctx *ctx = userdata;
	dav_xml_elem *elem;
	dav_text_header *hdr;
	const char *s;

	/* punt once we find an error */
	if (ctx->error)
	return;

	elem = ctx->cur_elem;
	s = ap_pstrndup(ctx->p, data, len);

	if (elem->last_child == NULL) {
	/* no children yet. this cdata follows the start tag */
	hdr = &elem->first_cdata;
	}
	else {
	/* child elements exist. this cdata follows the last child. */
	hdr = &elem->last_child->following_cdata;
	}

	dav_text_append(ctx->p, hdr, s);
	}

	int dav_parse_input(request_rec * r, dav_xml_doc **pdoc)
	{
	int result;
	dav_xml_ctx ctx =
	{0};
	XML_Parser parser;

	if ((result = ap_setup_client_block(r, REQUEST_CHUNKED_DECHUNK)) != OK)
	return result;

	if (r->remaining == 0) {
	*pdoc = NULL;
	return OK;
	}

	ctx.p = r->pool;
	ctx.doc = ap_pcalloc(ctx.p, sizeof(*ctx.doc));

	ctx.doc->namespaces = ap_make_array(ctx.p, 5, sizeof(const char *));
	dav_insert_uri(ctx.doc->namespaces, "DAV:");

	/* ### we should get the encoding from Content-Encoding */
	parser = XML_ParserCreate(NULL);
	if (parser == NULL) {
	/* ### anything better to do? */
	fprintf(stderr, "Ouch! XML_ParserCreate() failed!\n");
	exit(1);
	}

	XML_SetUserData(parser, (void *) &ctx);
	XML_SetElementHandler(parser, dav_start_handler, dav_end_handler);
	XML_SetCharacterDataHandler(parser, dav_cdata_handler);

	if (ap_should_client_block(r)) {
	long len;
	char *buffer;
	char end;
	int rv;
	size_t total_read = 0;
	size_t limit_xml_body = dav_get_limit_xml_body(r);

	/* allocate our working buffer */
	buffer = ap_palloc(r->pool, DAV_READ_BLOCKSIZE);

	/* read the body, stuffing it into the parser */
	while ((len = ap_get_client_block(r, buffer, DAV_READ_BLOCKSIZE)) > 0) {
	total_read += len;
	if (limit_xml_body && total_read > limit_xml_body) {
	ap_log_rerror(APLOG_MARK, APLOG_NOERRNO \| APLOG_ERR, r,
	"XML request body is larger than the configured "
	"limit of %lu", (unsigned long)limit_xml_body);
	goto read_error;
	}

	rv = XML_Parse(parser, buffer, len, 0);
	if (rv == 0)
	goto parser_error;
	}
	if (len == -1) {
	/* ap_get_client_block() has logged an error */
	goto read_error;
	}

	/* tell the parser that we're done */
	rv = XML_Parse(parser, &end, 0, 1);
	if (rv == 0)
	goto parser_error;
	}

	XML_ParserFree(parser);

	if (ctx.error) {
	switch (ctx.error) {
	case DAV_NS_ERROR_UNKNOWN_PREFIX:
	ap_log_rerror(APLOG_MARK, APLOG_ERR \| APLOG_NOERRNO, r,
	"An undefined namespace prefix was used.");
	break;

	default:
	ap_log_rerror(APLOG_MARK, APLOG_ERR \| APLOG_NOERRNO, r,
	"There was an error within the XML request body.");
	break;
	}

	/* Apache will supply a default error, plus the error log above. */
	return HTTP_BAD_REQUEST;
	}

	/* ### assert: ctx.cur_elem == NULL */

	*pdoc = ctx.doc;

	return OK;

	parser_error:
	{
	enum XML_Error err = XML_GetErrorCode(parser);

	/* ### fix this error message (default vs special) */
	ap_log_rerror(APLOG_MARK, APLOG_ERR \| APLOG_NOERRNO, r,
	"XML parser error code: %s (%d).",
	XML_ErrorString(err), err);

	XML_ParserFree(parser);

	/* Apache will supply a default error, plus the error log above. */
	return HTTP_BAD_REQUEST;
	}

	read_error:
	XML_ParserFree(parser);

	/* Apache will supply a default error, plus whatever was logged. */
	return HTTP_BAD_REQUEST;
	}