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Posted to c-dev@xerces.apache.org by Alberto Massari <am...@progress.com> on 2003/10/06 15:50:27 UTC
Re: Core dump in xerces-c-2_2_0
Hi Peter,
your code is changing the value for the "name" pointer, so when you are
trying to release the buffer, you are using a different pointer from the
one the system returned you.
Different OSs can behave in different ways: some can check that that
pointer doesn't point to a valid block and simply skip the deallocation,
other can just crash because they end up looking to invalid data.
Just use the second version, that's the correct one (well, to say the whole
truth, that routine is also not checking for the target array to be big
enough to hold the data, and doesn't test for getNodeValue not to return a
NULL pointer.....)
Alberto
At 14.29 06/10/2003 +0100, Peter Guyatt wrote:
>Hi There,
>
> I have just come accross a rather strange error in the Xerces
> library (cc
>build for solaris 2.7).
>
>The following code causes the library to core dump:
>
>/** Function to get the value of a node
> This functon takes care of allocating memory and freeing it and
> returning the name of the node copied into a static character
> array */
>static void getNodeValue (char *data, const DOMNode *node)
>{
> //get the name of the DOM node
> char *name = XMLString::transcode(node->getNodeValue());
> int index = 0;
> //only extract text with no ws characterc
> while(*name)//isspace(*name))
> {
> if (!isspace(*name))
> {
> data[index++] = *name;
> }
> //move to the next character
> name ++;
> }
> //set the end of the string
> data[index] = 0;
> //release the memory
> XMLString::release(&name);
>}
>
>the core dump occurrs in the XMLString::release method, but it works fine
>when running the Xerces library on windows.
>
>However it does not core dump immediately, only after processing about half
>of the document and the below code seems to fix it.
>
>static void getNodeValue (char *data, const DOMNode *node)
>{
> //get the name of the DOM node
> char *tmp = XMLString::transcode(node->getNodeValue());
> char *name = tmp;
> int index = 0;
> //only extract text with no ws characterc
> while(*name)//isspace(*name))
> {
> if (!isspace(*name))
> {
> data[index++] = *name;
> }
> //move to the next character
> name ++;
> }
> //set the end of the string
> data[index] = 0;
> //release the memory
> XMLString::release(&tmp);
>}
>
>Could anyone please tell me if there is a bug already raised on this or at
>least offer a reason for the core dump.
>
>Thanks
>
>Pete
>
>
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RE: Core dump in xerces-c-2_2_0
Posted by Peter Guyatt <pg...@telesoft-technologies.com>.
Hi There,
Thanks for that, I knwe it was not perfect it was a very quick and dirty
hack to be completely honest.
Thanks
Pete
-----Original Message-----
From: Alberto Massari [mailto:amassari@progress.com]
Sent: 06 October 2003 14:50
To: xerces-c-dev@xml.apache.org
Subject: Re: Core dump in xerces-c-2_2_0
Hi Peter,
your code is changing the value for the "name" pointer, so when you are
trying to release the buffer, you are using a different pointer from the
one the system returned you.
Different OSs can behave in different ways: some can check that that
pointer doesn't point to a valid block and simply skip the deallocation,
other can just crash because they end up looking to invalid data.
Just use the second version, that's the correct one (well, to say the whole
truth, that routine is also not checking for the target array to be big
enough to hold the data, and doesn't test for getNodeValue not to return a
NULL pointer.....)
Alberto
At 14.29 06/10/2003 +0100, Peter Guyatt wrote:
>Hi There,
>
> I have just come accross a rather strange error in the Xerces
> library (cc
>build for solaris 2.7).
>
>The following code causes the library to core dump:
>
>/** Function to get the value of a node
> This functon takes care of allocating memory and freeing it and
> returning the name of the node copied into a static character
> array */
>static void getNodeValue (char *data, const DOMNode *node)
>{
> //get the name of the DOM node
> char *name = XMLString::transcode(node->getNodeValue());
> int index = 0;
> //only extract text with no ws characterc
> while(*name)//isspace(*name))
> {
> if (!isspace(*name))
> {
> data[index++] = *name;
> }
> //move to the next character
> name ++;
> }
> //set the end of the string
> data[index] = 0;
> //release the memory
> XMLString::release(&name);
>}
>
>the core dump occurrs in the XMLString::release method, but it works fine
>when running the Xerces library on windows.
>
>However it does not core dump immediately, only after processing about half
>of the document and the below code seems to fix it.
>
>static void getNodeValue (char *data, const DOMNode *node)
>{
> //get the name of the DOM node
> char *tmp = XMLString::transcode(node->getNodeValue());
> char *name = tmp;
> int index = 0;
> //only extract text with no ws characterc
> while(*name)//isspace(*name))
> {
> if (!isspace(*name))
> {
> data[index++] = *name;
> }
> //move to the next character
> name ++;
> }
> //set the end of the string
> data[index] = 0;
> //release the memory
> XMLString::release(&tmp);
>}
>
>Could anyone please tell me if there is a bug already raised on this or at
>least offer a reason for the core dump.
>
>Thanks
>
>Pete
>
>
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>For additional commands, e-mail: xerces-c-dev-help@xml.apache.org
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