in reply to (tye)Re2: XS question: typemap for a pointer to a pointer?
in thread XS question: typemap for a pointer to a pointer?

This what you're asking for? 
/*
 * This file was generated automatically by xsubpp version 1.9507 from
+ the 
 * contents of LibnetRaw.xs. Do not edit this file, edit LibnetRaw.xs 
+instead.
 *
 *      ANY CHANGES MADE HERE WILL BE LOST! 
 *
 */

#line 1 "LibnetRaw.xs"
#include "EXTERN.h"
#include "perl.h"
#include "XSUB.h"
#include "libnet.h"


#line 17 "LibnetRaw.c"
XS(XS_Net__LibnetRaw_libnet_open_raw_sock)
{
    dXSARGS;
    if (items != 1)
        Perl_croak(aTHX_ "Usage: Net::LibnetRaw::libnet_open_raw_sock(
+protocol)");
    {
        int     protocol = (int)SvIV(ST(0));
        int     RETVAL;
        dXSTARG;

        RETVAL = libnet_open_raw_sock(protocol);
        XSprePUSH; PUSHi((IV)RETVAL);
    }
    XSRETURN(1);
}

XS(XS_Net__LibnetRaw_libnet_close_raw_sock)
{
    dXSARGS;
    if (items != 1)
        Perl_croak(aTHX_ "Usage: Net::LibnetRaw::libnet_close_raw_sock
+(fd)");
    {
        int     fd = (int)SvIV(ST(0));
        int     RETVAL;
        dXSTARG;

        RETVAL = libnet_close_raw_sock(fd);
        XSprePUSH; PUSHi((IV)RETVAL);
    }
    XSRETURN(1);
}

XS(XS_Net__LibnetRaw_libnet_write_ip)
{
    dXSARGS;
    if (items != 3)
        Perl_croak(aTHX_ "Usage: Net::LibnetRaw::libnet_write_ip(sock,
+ packet, len)");
    {
        int     sock = (int)SvIV(ST(0));
        u_char *        packet = (u_char *)SvPV(ST(1),PL_na);
        int     len = (int)SvIV(ST(2));
        int     RETVAL;
        dXSTARG;

        RETVAL = libnet_write_ip(sock, packet, len);
        XSprePUSH; PUSHi((IV)RETVAL);
    }
    XSRETURN(1);
}

XS(XS_Net__LibnetRaw_libnet_do_checksum)
{
    dXSARGS;
    if (items != 3)
        Perl_croak(aTHX_ "Usage: Net::LibnetRaw::libnet_do_checksum(bu
+f, protocol, len)");
    {
        u_char  buf = (u_char)SvUV(ST(0));
        int     protocol = (int)SvIV(ST(1));
        int     len = (int)SvIV(ST(2));
        int     RETVAL;
        dXSTARG;

        RETVAL = libnet_do_checksum(&buf, protocol, len);
        sv_setuv(ST(0), (UV)buf);
        SvSETMAGIC(ST(0));
        XSprePUSH; PUSHi((IV)RETVAL);
    }
    XSRETURN(1);
}

XS(XS_Net__LibnetRaw_libnet_init_packet)
{
    dXSARGS;
    if (items != 2)
        Perl_croak(aTHX_ "Usage: Net::LibnetRaw::libnet_init_packet(p_
+size, buf)");
    {
        size_t  p_size = (size_t)SvIV(ST(0));
        u_char *        buf = (u_char *)SvPV(ST(1),PL_na);
        int     RETVAL;
        dXSTARG;

        RETVAL = libnet_init_packet(p_size, &buf);
        sv_setpv((SV*)ST(1), buf);
        SvSETMAGIC(ST(1));
        XSprePUSH; PUSHi((IV)RETVAL);
    }
    XSRETURN(1);
}

XS(XS_Net__LibnetRaw_libnet_destroy_packet)
{
    dXSARGS;
    if (items != 1)
        Perl_croak(aTHX_ "Usage: Net::LibnetRaw::libnet_destroy_packet
+(buf)");
    {
        u_char *        buf = (u_char *)SvPV(ST(0),PL_na);
        int     RETVAL;
        dXSTARG;

        RETVAL = libnet_destroy_packet(&buf);
        XSprePUSH; PUSHi((IV)RETVAL);
    }
    XSRETURN(1);
}

XS(XS_Net__LibnetRaw_libnet_name_resolve)
{
    dXSARGS;
    if (items != 2)
        Perl_croak(aTHX_ "Usage: Net::LibnetRaw::libnet_name_resolve(h
+ostname, use_name)");
    {
        u_char *        hostname = (u_char *)SvPV(ST(0),PL_na);
        u_short use_name = (u_short)SvUV(ST(1));
        u_long  RETVAL;
        dXSTARG;

        RETVAL = libnet_name_resolve(hostname, use_name);
        XSprePUSH; PUSHu((UV)RETVAL);
    }
    XSRETURN(1);
}

XS(XS_Net__LibnetRaw_libnet_build_ip)
{
    dXSARGS;
    if (items != 11)
        Perl_croak(aTHX_ "Usage: Net::LibnetRaw::libnet_build_ip(len, 
+tos, id, frag, ttl, prot, saddr, daddr, payload, payload_s, buf)");
    {
        u_short len = (u_short)SvUV(ST(0));
        u_char  tos = (u_char)SvUV(ST(1));
        u_short id = (u_short)SvUV(ST(2));
        u_short frag = (u_short)SvUV(ST(3));
        u_char  ttl = (u_char)SvUV(ST(4));
        u_char  prot = (u_char)SvUV(ST(5));
        u_long  saddr = (u_long)SvUV(ST(6));
        u_long  daddr = (u_long)SvUV(ST(7));
        const u_char *  payload = (const u_char *)SvPV(ST(8),PL_na);
        int     payload_s = (int)SvIV(ST(9));
        u_char  buf = (u_char)SvUV(ST(10));
        int     RETVAL;
        dXSTARG;

        RETVAL = libnet_build_ip(len, tos, id, frag, ttl, prot, saddr,
+ daddr, payload, payload_s, &buf);
        sv_setuv(ST(10), (UV)buf);
        SvSETMAGIC(ST(10));
        XSprePUSH; PUSHi((IV)RETVAL);
    }
    XSRETURN(1);
}

XS(XS_Net__LibnetRaw_libnet_build_tcp)
{
    dXSARGS;
    if (items != 10)
        Perl_croak(aTHX_ "Usage: Net::LibnetRaw::libnet_build_tcp(spor
+t, dport, seq, ack, control, win, urg, payload, payload_s, buf)");
    {
        u_short sport = (u_short)SvUV(ST(0));
        u_short dport = (u_short)SvUV(ST(1));
        u_long  seq = (u_long)SvUV(ST(2));
        u_long  ack = (u_long)SvUV(ST(3));
        u_char  control = (u_char)SvUV(ST(4));
        u_short win = (u_short)SvUV(ST(5));
        u_short urg = (u_short)SvUV(ST(6));
        const u_char *  payload = (const u_char *)SvPV(ST(7),PL_na);
        int     payload_s = (int)SvIV(ST(8));
        u_char  buf = (u_char)SvUV(ST(9));
        int     RETVAL;
        dXSTARG;

        RETVAL = libnet_build_tcp(sport, dport, seq, ack, control, win
+, urg, payload, payload_s, &buf);
        sv_setuv(ST(9), (UV)buf);
        SvSETMAGIC(ST(9));
        XSprePUSH; PUSHi((IV)RETVAL);
    }
    XSRETURN(1);
}

#ifdef __cplusplus
extern "C"
#endif
XS(boot_Net__LibnetRaw)
{
    dXSARGS;
    char* file = __FILE__;

    XS_VERSION_BOOTCHECK ;

        newXS("Net::LibnetRaw::libnet_open_raw_sock", XS_Net__LibnetRa
+w_libnet_open_raw_sock, file);
        newXS("Net::LibnetRaw::libnet_close_raw_sock", XS_Net__LibnetR
+aw_libnet_close_raw_sock, file);
        newXS("Net::LibnetRaw::libnet_write_ip", XS_Net__LibnetRaw_lib
+net_write_ip, file);
        newXS("Net::LibnetRaw::libnet_do_checksum", XS_Net__LibnetRaw_
+libnet_do_checksum, file);
        newXS("Net::LibnetRaw::libnet_init_packet", XS_Net__LibnetRaw_
+libnet_init_packet, file);
        newXS("Net::LibnetRaw::libnet_destroy_packet", XS_Net__LibnetR
+aw_libnet_destroy_packet, file);
        newXS("Net::LibnetRaw::libnet_name_resolve", XS_Net__LibnetRaw
+_libnet_name_resolve, file);
        newXS("Net::LibnetRaw::libnet_build_ip", XS_Net__LibnetRaw_lib
+net_build_ip, file);
        newXS("Net::LibnetRaw::libnet_build_tcp", XS_Net__LibnetRaw_li
+bnet_build_tcp, file);
    XSRETURN_YES;
}

[download]
Just for concenience, the typemap: 
u_char *        T_PV
u_char          T_UV
u_short         T_UV
u_long          T_UV
const u_char *  T_PV

[download]
Perhaps I am thinking of a pointer to a pointer in the wrong fashion or I am confusing the ways in which perl reference work that I am not clear on. I truly appreciate your help!

Replies are listed 'Best First'.
(tye)Re3: XS question: typemap for a pointer to a pointer?
by tye (Sage) on Apr 11, 2001 at 18:24 UTC

    Yeah, that's it! Now for the relavent bits: 

    XS(XS_Net__LibnetRaw_libnet_do_checksum)
[...]
        u_char  buf = (u_char)SvUV(ST(0));
[...]
        RETVAL = libnet_do_checksum(&buf, protocol, len);
        sv_setuv(ST(0), (UV)buf);
        SvSETMAGIC(ST(0));

    [download]
    The above is exactly what you want. You need to make the other functions handle buf the same way this one does. You also got it correct for Net__LibnetRaw_libnet_build_ip and Net__LibnetRaw_libnet_build_tcp. 
    XS(XS_Net__LibnetRaw_libnet_destroy_packet)
[...]
        u_char *        buf = (u_char *)SvPV(ST(0),PL_na);
        RETVAL = libnet_destroy_packet(&buf);

    [download]
     You want to add some code here that destroys the buf object. Probably just: 
        OUTPUT:
        buf    sv_setsv(ST(0),&PL_sv_undef);

    [download]
    Now for the source of your problem (I think): 
    XS(XS_Net__LibnetRaw_libnet_init_packet)
[...]
        u_char *        buf = (u_char *)SvPV(ST(1),PL_na);
[...]
        RETVAL = libnet_init_packet(p_size, &buf);
        sv_setpv((SV*)ST(1), buf);

    [download]
     This function seems to have used a different typemap for buf which is trying to extract the '\0'-terminated string that it is supposed to point to. I think all you need to do is fix this typemap to be like the other functions.

    I'm going to check some other things I noticed and I'll reply separately if I detect any problems.

            - tye (but my friends call me "Tye")
[reply]
[d/l]
[select]
(tye)Re4: XS question: typemap for a pointer to a pointer?
by tye (Sage) on Apr 11, 2001 at 19:02 UTC 

    XS(XS_Net__LibnetRaw_libnet_write_ip)
{
    dXSARGS;
    if (items != 3)
        Perl_croak(aTHX_ "Usage: Net::LibnetRaw::libnet_write_ip(sock,
+ packet, len)");
    {
        int     sock = (int)SvIV(ST(0));
        u_char *        packet = (u_char *)SvPV(ST(1),PL_na);
        int     len = (int)SvIV(ST(2));
        int     RETVAL;
        dXSTARG;

        RETVAL = libnet_write_ip(sock, packet, len);
        XSprePUSH; PUSHi((IV)RETVAL);
    }
    XSRETURN(1);
}

    [download]
    I'd make len default to 0 (change "len" to "len=0" the first place it is mentioned) and add: 
        INIT:
        if(  0 == len  )
            len= SvCUR(ST(1));

    [download]
    so that write_ip($sock,$packet) works.

            - tye (but my friends call me "Tye")
[reply]
[d/l]
[select]
      Ok. Here's what I tried, but libnet_build_ip() is still crapping. I understand what you said about making all the functions accept the same type at the end of your Re4. Some where accepting the buf itself and others a pointer to it even when my calls were using passing simply $buf each time. This is how I changed the XS file to fix this (I think) for the two functions in question:

      int
libnet_init_packet(p_size, buf)
                size_t p_size
                u_char & buf
        CODE:
                u_char * buf_temp;
                buf_temp = &buf;
                RETVAL = libnet_init_packet(p_size, &buf_temp);
        OUTPUT:
                RETVAL
                buf

int
libnet_destroy_packet(buf)
                u_char & buf
        CODE:
                u_char * buf_temp;
                buf_temp = &buf;
                RETVAL = libnet_destroy_packet(&buf_temp);
        OUTPUT:
                RETVAL
                buf     sv_setsv(ST(0),&PL_sv_undef);

      [download]
      The resultant C code appears to hold the proper type for the passed in $buf now... 
      XS(XS_Net__LibnetRaw_libnet_init_packet)
{
    dXSARGS;
    if (items != 2)
        Perl_croak(aTHX_ "Usage: Net::LibnetRaw::libnet_init_packet(p_
+size, buf)");
    {
        size_t  p_size = (size_t)SvIV(ST(0));
        u_char  buf = (u_char)SvUV(ST(1));
        int     RETVAL;
        dXSTARG;
#line 39 "LibnetRaw.xs"
                u_char * buf_temp;
                buf_temp = &buf;
                RETVAL = libnet_init_packet(p_size, &buf_temp);
#line 106 "LibnetRaw.c"
        sv_setuv(ST(1), (UV)buf);
        SvSETMAGIC(ST(1));
        XSprePUSH; PUSHi((IV)RETVAL);
    }
    XSRETURN(1);
}

XS(XS_Net__LibnetRaw_libnet_destroy_packet)
{
    dXSARGS;
    if (items != 1)
        Perl_croak(aTHX_ "Usage: Net::LibnetRaw::libnet_destroy_packet
+(buf)");
    {
        u_char  buf = (u_char)SvUV(ST(0));
        int     RETVAL;
        dXSTARG;
#line 50 "LibnetRaw.xs"
                u_char * buf_temp;
                buf_temp = &buf;
                RETVAL = libnet_destroy_packet(&buf_temp);
#line 127 "LibnetRaw.c"
        sv_setsv(ST(0),&PL_sv_undef);
        SvSETMAGIC(ST(0));
        XSprePUSH; PUSHi((IV)RETVAL);
    }
    XSRETURN(1);
}

      [download]
      So now, the type for buf passed in is u_char just like the other calls. I just noticed some other value vs. pointer to value mistakes I've made (It seems * and & are not quite as similar as I thought). That aside, I still think the error I am getting does not make sense.
[reply]
[d/l]
[select]

        No, you've made things worse. buf needs to always be u_char * or u_char * &. u_char & is completely different.

        Try again and/or reread what I wrote. You want $buf to hold an opaque UV that gets converted to/from a u_char *. Some of your calls should pass a reference to this u_char * rather than passing the u_char * directly (that is what the "&" is for). Those routines are the ones that might change the pointer (by allocating or reallocating the memory) and are also the ones that need buf mentioned in the OUTPUT: section.

                - tye (but my friends call me "Tye")
[reply]
[d/l]
[select]

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