[SOLVED] DHCPCTL : how to use it

zelycorn · 08-01-2011, 08:05 AM

Hello,

i would like to implement dhcpctl in a program to manipulate dhcp leases.

It doesn't work and there are errors at compilation :

/tmp/ccYPRIt5.o: In function `LeaseCleaning(std::basic_string<char, std::char_traits<char>, std::allocator<char> >)':
pxe.cpp

.text+0x133a): undefined reference to `dhcpctl_initialize()'
pxe.cpp

.text+0x1352): undefined reference to `dhcpctl_connect(__omapi_object**, char const*, int, __omapi_object*)'
collect2: ld returned 1 exit status

Code:

#include <stdarg.h> 
#include <sys/socket.h> 
#include <netinet/in.h> 
#include <isc-dhcp/result.h> 
#include <dhcpctl.h>
#include <omapip/omapip.h>

dhcpctl_data_string ipaddrstring = NULL; 
	dhcpctl_data_string value = NULL; 
	dhcpctl_handle connection = NULL; 
	dhcpctl_handle lease = NULL; 
	isc_result_t waitstatus; 
	struct in_addr convaddr; 
	time_t thetime; 
	dhcpctl_initialize (); 
	dhcpctl_connect (&connection, "127.0.0.1", 9991, 0); 
	//hcpctl_new_object (&lease, connection, "lease");

g++ -o /home/ff/pxe /home/ff/pxe.cpp -I/usr/include/libxml2 -ldhcpctl -lomapi -ldst

gregvp · 08-01-2011, 10:34 PM

The compiler is not finding dhcpctl.h. As the code is written it expects to find it in /usr/include/.

zelycorn · 08-02-2011, 01:48 AM

It is not so easy :
locate dhcpctl.h
/usr/include/dhcpctl.h

I'have already checked this.

paulsm4 · 08-02-2011, 01:58 AM

Hi -

Quote:

The compiler is not finding dhcpctl.h.

No, actually the error says that the LINKER isn't finding dhcpctl_initialize() or dhcpctl_connect().

The OP seems to be linking the correct library, "-ldhcpctl".

It's entirely possible the library is somehow invalid, or missing these symbols. It wouldn't hurt to run "nm libdhcpctl*|less" to see if these symbols are defined in the library.

It also might not hurt to try re-installing the package (library and headers).

One final test would be to write a standalone "C" program (instead of C++), invoke dhcpctl_initialize() and dhcpctl_connect(), build it with "gcc" (instead of g++) and see if it fails the same way.

zelycorn · 08-02-2011, 02:12 AM

I will try to compile a c program with only dhcpctl includes and functions.

zelycorn · 08-02-2011, 02:57 AM

A test in c :

gcc -o test -L/usr/lib64/ -ldst -lomapi -ldhcpctl -I/usr/include/ test.c
/tmp/ccW17ihL.o: In function `main':
test.c

.text+0x29): undefined reference to `dhcpctl_initialize'
test.c

.text+0x41): undefined reference to `dhcpctl_connect'
collect2: ld returned 1 exit status

Code:

#include <stdio.h>
#include <stdlib.h>

#include <stdarg.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <isc-dhcp/result.h>
#include <dhcpctl.h>
#include <omapip/omapip.h>


main () {

dhcpctl_data_string ipaddrstring = NULL;
  dhcpctl_data_string value = NULL;
  dhcpctl_handle connection = NULL;
  dhcpctl_handle lease = NULL;
  isc_result_t waitstatus;
  struct in_addr convaddr;
  time_t thetime;
  dhcpctl_initialize ();
  dhcpctl_connect (&connection, "10.47.35.5", 9991, 0);
  //hcpctl_new_object (&lease, connection, "lease");
fflush(stdout);
}

zelycorn · 08-02-2011, 03:27 AM

I also copied libdhcpctl.a and libdest.a from /usr/lib64 to /usr/lib.

zelycorn · 08-02-2011, 09:10 AM

So i know how to deal with dhcpctl by now :

only use c and not c++ thanks to paulsm4 !

gcc /root/test.c -o test -ldhcpctl -lomapi -ldst

cp /root/test.c /root/test.cpp
g++ /root/test.cpp -o test -ldhcpctl -lomapi -ldst
/tmp/ccuTsGfJ.o: In function `main':
test.cpp

.text+0x9): undefined reference to `dhcpctl_initialize()'
test.cpp

.text+0x21): undefined reference to `dhcpctl_connect(__omapi_object**, char const*, int, __omapi_object*)'
collect2: ld returned 1 exit status