Calling inet_addr from a C++ udf

[Mike Hubbard]

Hello -

I want to write a very simple User Defined Function in C++ that takes
in a VARCHAR(15) and runs it through inet_addr to return the integer
representation of an IP. My trouble is that I can't seem to call
inet_addr without getting: SQL0430N User defined function
"SECUREWORKS.IP_TO_INT" (specific name
"SQL040617075607700") has abnormally terminated. SQLSTATE=38503

It truly seems to be in the call itself and not my parameters because,
for the sake of testing, I have hard coded an integer return and then
just called inet_addr "on the side" with a simple statement something
like

long lAddress = inet_addr("172.16.55.55");

Has anyone successfully done this before or does anyone have any
helpful suggestions?

Thanks very much
Michael J. Hubbard

[Paul Vernon]

"Mike Hubbard" <mh******@secureworks.com> wrote in message
news:f3**************************@posting.google.c om...

Hello -

I want to write a very simple User Defined Function in C++ that takes
in a VARCHAR(15) and runs it through inet_addr to return the integer
representation of an IP. My trouble is that I can't seem to call
inet_addr without getting: SQL0430N User defined function
"SECUREWORKS.IP_TO_INT" (specific name
"SQL040617075607700") has abnormally terminated. SQLSTATE=38503

Could just do it in SQL, although remember that SQL only has signed integers
and the below only works if you keep leading zeros in the character
representation.

CREATE FUNCTION F.DSPLY2IPV4 (IP VARCHAR(15))
RETURNS INTEGER
LANGUAGE SQL CONTAINS SQL NO EXTERNAL ACTION DETERMINISTIC
RETURN
(INT(SUBSTR(ip,1,3)) - 128) * 16777216
+ INT(SUBSTR(ip,5,3)) * 65536
+ INT(SUBSTR(ip,9,3)) * 256
+ (INT(SUBSTR(ip,13,3)))
;
COMMENT ON FUNCTION "F"."DSPLY2IPV4" IS
'Coverts an IP address from the standard character representaion of 4
decimal group [0-255] to a signed integer representation. Only works if
leading zeros are kept'
;
C:\SQL>db2 values F.DSPLY2IPV4 ('000.000.000.000'), F.DSPLY2IPV4
('255.255.255.255')

1
-----------
-2147483648
2147483647

2 record(s) selected.
Regards
Paul Vernon
Business Intelligence, IBM Global Services

[Knut Stolze]

Mike Hubbard wrote:

Hello -

I want to write a very simple User Defined Function in C++ that takes
in a VARCHAR(15) and runs it through inet_addr to return the integer
representation of an IP. My trouble is that I can't seem to call
inet_addr without getting: SQL0430N User defined function
"SECUREWORKS.IP_TO_INT" (specific name
"SQL040617075607700") has abnormally terminated. SQLSTATE=38503

A SQL0430 means that your UDF code is faulty and crashed. Could you please
show the C code that you used so that we can have a look at it and probably
find the issue that way?
--
Knut Stolze
Information Integration
IBM Germany / University of Jena

[Mike Hubbard]

Knut Stolze <st****@de.ibm.com> wrote in message news:<cb**********@fsuj29.rz.uni-jena.de>...

Mike Hubbard wrote:

Hello -

I want to write a very simple User Defined Function in C++ that takes
in a VARCHAR(15) and runs it through inet_addr to return the integer
representation of an IP. My trouble is that I can't seem to call
inet_addr without getting: SQL0430N User defined function
"SECUREWORKS.IP_TO_INT" (specific name
"SQL040617075607700") has abnormally terminated. SQLSTATE=38503

A SQL0430 means that your UDF code is faulty and crashed. Could you please
show the C code that you used so that we can have a look at it and probably
find the issue that way?

extern "C" {
#include <stdio.h>
#include <string.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <sqludf.h>
};

#include "sqlsystm.h"

int CharToInt(char cCharToConvert);
char IntToChar(short iCharToConvert);

#define ASCII_ZERO = 48

extern "C" void SQL_API_FN ip_to_int(SQLUDF_VARCHAR *IPAddress,
long *IPOut,
short *input_ind,
short *output_ind,
char sqlstate[6],
char fname[28],
char finst[19],
char msgtext[71])
{
// long lTestLong = inet_addr("172.111.111.55");
*IPOut = 5555;
return;
}

If I compile the program as you see it and run the function, I get
lots of 5's. If I comment back in the call to inet_addr (which, as
written, has no baring on any of the parameters), I crash.

[Knut Stolze]

Mike Hubbard wrote:

Knut Stolze <st****@de.ibm.com> wrote in message
news:<cb**********@fsuj29.rz.uni-jena.de>...

Mike Hubbard wrote:

> Hello -
>
> I want to write a very simple User Defined Function in C++ that takes
> in a VARCHAR(15) and runs it through inet_addr to return the integer
> representation of an IP. My trouble is that I can't seem to call
> inet_addr without getting: SQL0430N User defined function
> "SECUREWORKS.IP_TO_INT" (specific name
> "SQL040617075607700") has abnormally terminated. SQLSTATE=38503
A SQL0430 means that your UDF code is faulty and crashed. Could you
please show the C code that you used so that we can have a look at it and
probably find the issue that way?

extern "C" {
#include <stdio.h>
#include <string.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <sqludf.h>
};

#include "sqlsystm.h"

You don't need that. As long as you include <sqludf.h>, you have sqlsystm.h
already. (I hope you didn't modify the header file manually? That would
be a rather stupid idea...)
int CharToInt(char cCharToConvert);
char IntToChar(short iCharToConvert);

#define ASCII_ZERO = 48

extern "C" void SQL_API_FN ip_to_int(SQLUDF_VARCHAR *IPAddress,
long *IPOut,
short *input_ind,
short *output_ind,
char sqlstate[6],
char fname[28],
char finst[19],
char msgtext[71])
I would use the following function declaration instead:

extern "C"
void SQL_API_FN ip_to_int(
SQLUDF_VARCHAR *IPAddress,
SQLUDF_INTEGER *IPOut,
SQLUDF_NULLIND *input_ind,
SQLUDF_NULLIND *output_ind,
SQLUDF_TRAIL_ARGS)

The advantage is simply that you will not have any further problems with the
data types and you will also have the correct parameters. Note that if
there is a parameter missing or if you have too many parameters, then DB2
will not put the right number of values on the stack, causing a stack
corruption. All sorts of weird problems can come into play then.
{
// long lTestLong = inet_addr("172.111.111.55");
You are aware that "inet_addr" is an obsolete function and you might want to
consider "inet_aton" instead?
*IPOut = 5555;
return;
}

If I compile the program as you see it and run the function, I get
lots of 5's.
"Lots of 5's" means four 5's? If not, then you already have a problem
there.
If I comment back in the call to inet_addr (which, as
written, has no baring on any of the parameters), I crash.

I assume that your CREATE FUNCTION statement looks like this?

CREATE FUNCTION ip_to_int(ip VARCHAR(15))
RETURNS INTEGER
EXTERNAL NAME 'test_lib!ip_to_int'
LANGUAGE C
PARAMETER STYLE SQL
DETERMINISTIC -- seems to be a very good idea here
FENCED THREADSAFE
RETURNS NULL ON NULL INPUT
NO SQL
NO EXTERNAL ACTION
NO SCRATCHPAD -- !!!
NO FINAL CALL -- !!!
ALLOW PARALLEL
NO DBINFO -- !!!

If your function definition includes any of the scratchpad/final call/dbinfo
clauses, then you run stright into the problem with the corrupted stack I
mentioned above because your function prototype doesn't match with what DB2
expects.

With this CREATE FUNCTION statement, I could run your code and it worked
very well. So I suspect a problem with your parameters.

Also, you did restart DB2 to make sure that the new version of your library
was picked up after you modified the source code and recompiled it?
Otherwise, DB2 will simply reuse the library it already loaded before.

--
Knut Stolze
Information Integration
IBM Germany / University of Jena