Re: I don't understand what is going on with memory control in a client.

2008-03-30 Thread Manjula Peiris 

On Fri, 2008-03-28 at 15:20 -0400, Alex Bolgarov wrote:
 I tried with the echo sample - compiled both service and client from
 the source code. All worked OK, without crashes in both cases - when
 the request is successful and when the request fails because I did not
 start the service. And I run the client through the valgrind, there
 are no memory leaks (at least the small leaks that valgrind reports
 are not increasing after I put the call of send_receive() into loop
 and started increasing number of iterations). So it looks that the
 echo sample contains correct sequence of operations.
 
 Should not the (wrong) examples in the online user manual be updated too?

Thanks Alex for pointing this out. We will fix this for the next
release. It is great if you can raise a JIRA issue [1] on this.

[1] http://issues.apache.org/jira/browse/AXIS2C

Thanks,
-Manjula.

 
 
 On Wed, Mar 26, 2008 at 11:10 PM, Samisa Abeysinghe [EMAIL PROTECTED] wrote:
  Try with echo sample.
 
   Samisa...
 
 
 
   Alex Bolgarov wrote:
Well, I _am_ using the sample provided by the Axis project - the
client I'm using is the exact code sample from the Axis2/C Manual -
the manual that is available here:
http://ws.apache.org/axis2/c/docs/axis2c_manual.html. The sample
client code I'm using is, without any changes, from this page:
http://ws.apache.org/axis2/c/docs/hello/client/hello.c.html (I'm
attaching the file that I was compiling, just in case there are some
differences I could not see, but I've just copied the code from the
web browser window and pasted it into XEmacs editor and saved as a
'my_client.c' file)
   
And, as you can see in the sample client code, this sample _releases_
a payload memory that is passes to the send_receive operation:
   
if (payload)
{
axiom_node_free_tree(payload, env);
payload = NULL;
}
   
Is the sample wrong? I will take a look at the samples from the source
distribution, may be they don't release the payload?
   
Anyway, when the service _is_ running and the client receives the
response, why attempt to release the payload tree by the client (which
this sample client does) does not cause the crash? If the Axis took
ownership for the payload tree, it should have deleted it already, and
attempt to delete if in the client code would have caused a crash.
Something is not right here...
   
   
Thank you,
   
alex.
   
   
   
On Wed, Mar 26, 2008 at 10:30 AM, Samisa Abeysinghe [EMAIL PROTECTED] 
  wrote:
   
In short, the AXIOM that you create and pass to service client
 send_receive operation would be taken control of by service client. So,
 you do not have to free that, even though you will be creating it. Same
 with the returned response payload. You can use it, but you do not have
 ownership of that. All that you have to delete is the service client
 instance.
   
 If you can send in your client code, we can have a look.
   
 Also, the samples follow the convention that I explained above, so if
 you follow the samples, you can solve the problems.
   
 Samisa...
   
   
   
 Alex Bolgarov wrote:
  Hi,
 
  I don't understand what's going on inside the Axis2/C client. My test
  client crashes. I looked at the Axis source code and did some
  debugging (mostly, I've added a lots of AXIS2_LOG_DEBUG(...) to the
  Axis source code and recompiled - I have a fast enough computer, and
  this way you can receive repeating results, something that hard to 
  get
  with a debugger), and run a client code with valgrind.
 
  I think there might be some mix up in the the
  axis2_op_client_add_msg_ctx() function, which causes the memory that
  is not supposed to be freed by the Axis library (specifically, the
  payload data that is allocated by the client application before it
  calls the axis2_svc_client_send_receive()). Then, when the
  axis2_svc_client_send_receive() returns to my client code, the client
  tries to free the payload it allocated, at which moment the client
  crashes - either silently, or with the glibc reporting double free 
  or
  corruption.
 
  Now that I've got your attention, here are the details (sorry, this 
  is
  a long message):
 
  First, I'm using Ubuntu 7.10, and I downloaded and compiled sources 
  of
  Axis2/C 1.3.0.
 
  I compiled a SOAP service - virtually unchanged code of the example
  from the user guide, but the service looks to be OK, there is a
  problem with the client.
 
  I compiled a SOAP client - absolutely unchanged code of the client
  from the user guide
  (http://ws.apache.org/axis2/c/docs/hello/client/hello.c.html).
 
  When I'm starting the Axis server (for example, stand-alone
  axis2_http_server application), the client works OK, it sends

Re: I don't understand what is going on with memory control in a client.

2008-03-28 Thread Alex Bolgarov 
I tried with the echo sample - compiled both service and client from
the source code. All worked OK, without crashes in both cases - when
the request is successful and when the request fails because I did not
start the service. And I run the client through the valgrind, there
are no memory leaks (at least the small leaks that valgrind reports
are not increasing after I put the call of send_receive() into loop
and started increasing number of iterations). So it looks that the
echo sample contains correct sequence of operations.

Should not the (wrong) examples in the online user manual be updated too?


On Wed, Mar 26, 2008 at 11:10 PM, Samisa Abeysinghe [EMAIL PROTECTED] wrote:
 Try with echo sample.

  Samisa...



  Alex Bolgarov wrote:
   Well, I _am_ using the sample provided by the Axis project - the
   client I'm using is the exact code sample from the Axis2/C Manual -
   the manual that is available here:
   http://ws.apache.org/axis2/c/docs/axis2c_manual.html. The sample
   client code I'm using is, without any changes, from this page:
   http://ws.apache.org/axis2/c/docs/hello/client/hello.c.html (I'm
   attaching the file that I was compiling, just in case there are some
   differences I could not see, but I've just copied the code from the
   web browser window and pasted it into XEmacs editor and saved as a
   'my_client.c' file)
  
   And, as you can see in the sample client code, this sample _releases_
   a payload memory that is passes to the send_receive operation:
  
   if (payload)
   {
   axiom_node_free_tree(payload, env);
   payload = NULL;
   }
  
   Is the sample wrong? I will take a look at the samples from the source
   distribution, may be they don't release the payload?
  
   Anyway, when the service _is_ running and the client receives the
   response, why attempt to release the payload tree by the client (which
   this sample client does) does not cause the crash? If the Axis took
   ownership for the payload tree, it should have deleted it already, and
   attempt to delete if in the client code would have caused a crash.
   Something is not right here...
  
  
   Thank you,
  
   alex.
  
  
  
   On Wed, Mar 26, 2008 at 10:30 AM, Samisa Abeysinghe [EMAIL PROTECTED] 
 wrote:
  
   In short, the AXIOM that you create and pass to service client
send_receive operation would be taken control of by service client. So,
you do not have to free that, even though you will be creating it. Same
with the returned response payload. You can use it, but you do not have
ownership of that. All that you have to delete is the service client
instance.
  
If you can send in your client code, we can have a look.
  
Also, the samples follow the convention that I explained above, so if
you follow the samples, you can solve the problems.
  
Samisa...
  
  
  
Alex Bolgarov wrote:
 Hi,

 I don't understand what's going on inside the Axis2/C client. My test
 client crashes. I looked at the Axis source code and did some
 debugging (mostly, I've added a lots of AXIS2_LOG_DEBUG(...) to the
 Axis source code and recompiled - I have a fast enough computer, and
 this way you can receive repeating results, something that hard to get
 with a debugger), and run a client code with valgrind.

 I think there might be some mix up in the the
 axis2_op_client_add_msg_ctx() function, which causes the memory that
 is not supposed to be freed by the Axis library (specifically, the
 payload data that is allocated by the client application before it
 calls the axis2_svc_client_send_receive()). Then, when the
 axis2_svc_client_send_receive() returns to my client code, the client
 tries to free the payload it allocated, at which moment the client
 crashes - either silently, or with the glibc reporting double free or
 corruption.

 Now that I've got your attention, here are the details (sorry, this is
 a long message):

 First, I'm using Ubuntu 7.10, and I downloaded and compiled sources of
 Axis2/C 1.3.0.

 I compiled a SOAP service - virtually unchanged code of the example
 from the user guide, but the service looks to be OK, there is a
 problem with the client.

 I compiled a SOAP client - absolutely unchanged code of the client
 from the user guide
 (http://ws.apache.org/axis2/c/docs/hello/client/hello.c.html).

 When I'm starting the Axis server (for example, stand-alone
 axis2_http_server application), the client works OK, it sends
 something to the service and receives some response. No crashes.

 But if I start the client application _without_ starting a server
 (that is, I expect some kind of timeout or some error about inability
 to conect to the server), the client application crashes.

 Here is what I found:

 The axis2_svc_client_send_receive() calls

I don't understand what is going on with memory control in a client.

2008-03-26 Thread Alex Bolgarov 
Hi,

I don't understand what's going on inside the Axis2/C client. My test
client crashes. I looked at the Axis source code and did some
debugging (mostly, I've added a lots of AXIS2_LOG_DEBUG(...) to the
Axis source code and recompiled - I have a fast enough computer, and
this way you can receive repeating results, something that hard to get
with a debugger), and run a client code with valgrind.

I think there might be some mix up in the the
axis2_op_client_add_msg_ctx() function, which causes the memory that
is not supposed to be freed by the Axis library (specifically, the
payload data that is allocated by the client application before it
calls the axis2_svc_client_send_receive()). Then, when the
axis2_svc_client_send_receive() returns to my client code, the client
tries to free the payload it allocated, at which moment the client
crashes - either silently, or with the glibc reporting double free or
corruption.

Now that I've got your attention, here are the details (sorry, this is
a long message):

First, I'm using Ubuntu 7.10, and I downloaded and compiled sources of
Axis2/C 1.3.0.

I compiled a SOAP service - virtually unchanged code of the example
from the user guide, but the service looks to be OK, there is a
problem with the client.

I compiled a SOAP client - absolutely unchanged code of the client
from the user guide
(http://ws.apache.org/axis2/c/docs/hello/client/hello.c.html).

When I'm starting the Axis server (for example, stand-alone
axis2_http_server application), the client works OK, it sends
something to the service and receives some response. No crashes.

But if I start the client application _without_ starting a server
(that is, I expect some kind of timeout or some error about inability
to conect to the server), the client application crashes.

Here is what I found:

The axis2_svc_client_send_receive() calls
axis2_svc_client_send_receive_with_op_qname() function that implements
the sending and receiving of the SOAP messages. If there is an error
in the low-level sending/receiving of the messages (which really
happens in my case, because I did not start the SOAP server for this
test), the res_msg_ctx variable will be NULL, and in the conditional
statement in the lines 864-872 of the file axis2_svc_client.c is
executed the 'else' alternative, which calls the
axis2_op_client_add_msg_ctx() function, passing the res_msg_ctx value
(which is NULL) to it.

In the axis2_op_client_add_msg_ctx() function, right before the 'if'
statement in the lines 274-296 (file axis_op_client.c):

if (out_msg_ctx  !mc)

 value of the out_msg_ctx is not NULL, and value of the mc is not NULL
(I checked this using the debug logging), so the body of this
statement is executed. In this body, right before the 'if' statement
on the line 290:

if (axutil_strcmp(dump_value, AXIS2_VALUE_TRUE))

the value of the dump_value is NULL (again checked by the debug
logging), and the axutil_strcmp() returns -1 (which is interpreted as
a 'true' boolean value), and thus the body of the statement, including
the call (line 292)

axis2_msg_ctx_free(out_msg_ctx, env);

is executed.

The out_msg_ctx here points to the same message context object that
was created in the axis2_svc_client_send_receive_with_op_qname()
function, before sending the SOAP request - I saw using the debug
logging that the pointer value returned by the axis2_msg_ctx_create()
call in the axis2_svc_client_send_receive_with_op_qname() (line 834)
is the same as the value of the pointer out_msg_ctx here.

But this message context object contains a soap_envelop object that,
in turn, contains the payload object (tree of the object model nodes)
that my client application allocated before calling the
axis2_svc_client_send_receive() (specifically, this soap_envelop is
filled with the payload in the call
axis2_svc_client_fill_soap_envelope() (line 838, function
axis2_svc_client_send_receive_with_op_qname(), file
axis2_svc_client.c). So, returning back to the the
axis2_op_client_add_msg_ctx() function, this payload object (tree)
gets freed here. Then, later, when my client application tries to free
the payload object after the axis2_svc_client_send_receive() returns
to it, the application crashes, because this memory is already freed.


So, finally, my questions:

What strategy the client application that calls
axis2_svc_client_send_receive() should use regarding
allocating/freeing memory? From the current implementation of Axis2/C,
it looks like a) if the response was received successfully, the client
application should free the payload, but b) if there was a
communication error, the Axis library will free the payload itself. Is
this correct?

Is this a 'by design' feature of the Axis2/C or is this a bug and (in
theory) there should be more sane rules regarding memory control?
(And, is there somewhere published the memory management rules for the
Axis2/C?)


Second thing I've noticed when browsing the code of the
axis2_svc_client_send_receive_with_op_qname() is

Re: I don't understand what is going on with memory control in a client.

2008-03-26 Thread Alex Bolgarov 
Well, I _am_ using the sample provided by the Axis project - the
client I'm using is the exact code sample from the Axis2/C Manual -
the manual that is available here:
http://ws.apache.org/axis2/c/docs/axis2c_manual.html. The sample
client code I'm using is, without any changes, from this page:
http://ws.apache.org/axis2/c/docs/hello/client/hello.c.html (I'm
attaching the file that I was compiling, just in case there are some
differences I could not see, but I've just copied the code from the
web browser window and pasted it into XEmacs editor and saved as a
'my_client.c' file)

And, as you can see in the sample client code, this sample _releases_
a payload memory that is passes to the send_receive operation:

if (payload)
{
axiom_node_free_tree(payload, env);
payload = NULL;
}

Is the sample wrong? I will take a look at the samples from the source
distribution, may be they don't release the payload?

Anyway, when the service _is_ running and the client receives the
response, why attempt to release the payload tree by the client (which
this sample client does) does not cause the crash? If the Axis took
ownership for the payload tree, it should have deleted it already, and
attempt to delete if in the client code would have caused a crash.
Something is not right here...


Thank you,

alex.



On Wed, Mar 26, 2008 at 10:30 AM, Samisa Abeysinghe [EMAIL PROTECTED] wrote:
 In short, the AXIOM that you create and pass to service client
  send_receive operation would be taken control of by service client. So,
  you do not have to free that, even though you will be creating it. Same
  with the returned response payload. You can use it, but you do not have
  ownership of that. All that you have to delete is the service client
  instance.

  If you can send in your client code, we can have a look.

  Also, the samples follow the convention that I explained above, so if
  you follow the samples, you can solve the problems.

  Samisa...



  Alex Bolgarov wrote:
   Hi,
  
   I don't understand what's going on inside the Axis2/C client. My test
   client crashes. I looked at the Axis source code and did some
   debugging (mostly, I've added a lots of AXIS2_LOG_DEBUG(...) to the
   Axis source code and recompiled - I have a fast enough computer, and
   this way you can receive repeating results, something that hard to get
   with a debugger), and run a client code with valgrind.
  
   I think there might be some mix up in the the
   axis2_op_client_add_msg_ctx() function, which causes the memory that
   is not supposed to be freed by the Axis library (specifically, the
   payload data that is allocated by the client application before it
   calls the axis2_svc_client_send_receive()). Then, when the
   axis2_svc_client_send_receive() returns to my client code, the client
   tries to free the payload it allocated, at which moment the client
   crashes - either silently, or with the glibc reporting double free or
   corruption.
  
   Now that I've got your attention, here are the details (sorry, this is
   a long message):
  
   First, I'm using Ubuntu 7.10, and I downloaded and compiled sources of
   Axis2/C 1.3.0.
  
   I compiled a SOAP service - virtually unchanged code of the example
   from the user guide, but the service looks to be OK, there is a
   problem with the client.
  
   I compiled a SOAP client - absolutely unchanged code of the client
   from the user guide
   (http://ws.apache.org/axis2/c/docs/hello/client/hello.c.html).
  
   When I'm starting the Axis server (for example, stand-alone
   axis2_http_server application), the client works OK, it sends
   something to the service and receives some response. No crashes.
  
   But if I start the client application _without_ starting a server
   (that is, I expect some kind of timeout or some error about inability
   to conect to the server), the client application crashes.
  
   Here is what I found:
  
   The axis2_svc_client_send_receive() calls
   axis2_svc_client_send_receive_with_op_qname() function that implements
   the sending and receiving of the SOAP messages. If there is an error
   in the low-level sending/receiving of the messages (which really
   happens in my case, because I did not start the SOAP server for this
   test), the res_msg_ctx variable will be NULL, and in the conditional
   statement in the lines 864-872 of the file axis2_svc_client.c is
   executed the 'else' alternative, which calls the
   axis2_op_client_add_msg_ctx() function, passing the res_msg_ctx value
   (which is NULL) to it.
  
   In the axis2_op_client_add_msg_ctx() function, right before the 'if'
   statement in the lines 274-296 (file axis_op_client.c):
  
   if (out_msg_ctx  !mc)
  
value of the out_msg_ctx is not NULL, and value of the mc is not NULL
   (I checked this using the debug logging), so the body of this
   statement is executed. In this body, right before the 'if' statement
   on the line 290:
  
   if