Lefrancois, Carl wrote:
Hi list,
Please help with some unexpected behaviour. This morning I started
using the functions axutil_stream_read and axutil_stream_write to modify
the contents of an AXIOM_DATA_SOURCE node in my payload, and I am
getting program crashes.
Can you send in the traces of the crashes?
Samisa...
I am using WSDL2C generated code stubs, and modifying the
axis2_stub_xx.c file to make changes to the payload. I inserted a
function at the top of the file and call this function just after the
payload is generated on the line:
payload = adb_<type>_serialize(_<type>, env, NULL, NULL,
AXIS2_TRUE, NULL, NULL);
modify_stream_contents(payload, env);
My function navigates the payload node to find the AXIOM_DATA_SOURCE
node. It then reads the contents into a buffer and does some
modification, then writes the modified data back into the stream. I'm
including a minimal version of the function below that only reads the
stream and writes it back again without modification.
The behaviour is strange: if the axutil_stream_write function specifies
a small count, the program doesn't crash. In my case, I can specify up
to 1665 bytes without a crash. (the full message size is 16860)
Am I doing something bad here? Are these stream functions meant to be
used in another way? The crash appears to be because of a buffer
overflow that mangles the state of other variables in the system.
(Axis2/C is version 1.3.0)
Any help is appreciated.
Carl
void modify_stream_contents(axiom_node_t *_node, const axutil_env_t
*env)
{
axiom_data_source_t *dataSource = NULL;
axutil_stream_t * stream = NULL;
axiom_node_t *currentNode = NULL;
axis2_char_t *buffer = NULL;
size_t streamSize = 0;
size_t readSize = 0;
// navigate to node that contains stream
currentNode = _node;
while (currentNode && (axiom_node_get_node_type(currentNode, env) !=
AXIOM_ELEMENT))
{
currentNode = axiom_node_get_next_sibling(currentNode, env);
}
currentNode = axiom_node_get_first_child(currentNode, env);
if (!currentNode || (axiom_node_get_node_type(currentNode, env) !=
AXIOM_DATA_SOURCE)) return;
// get stream
dataSource = (axiom_data_source_t *)
axiom_node_get_data_element(currentNode, env);
stream = axiom_data_source_get_stream(dataSource, env);
if (!stream) return;
streamSize = axutil_stream_get_len(stream, env);
buffer = (char *) AXIS2_MALLOC (env->allocator, sizeof (char) *
(streamSize));
readSize = axutil_stream_read (stream, env, buffer, streamSize);
readSize = axutil_stream_write (stream, env, buffer, 1665 );
// readSize = axutil_stream_write (stream, env, buffer, streamSize );
AXIS2_FREE (env->allocator, buffer);
}
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Samisa Abeysinghe
Director, Engineering; WSO2 Inc.
http://www.wso2.com/ - "The Open Source SOA Company"
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