op/readline_nb: non-threaded win32 croaks instead of failing on ioctl…

[tonycoz]

…(nonsocket)

And since it never succeeds on Win32, just skip.

Fixes #23335

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• This set of changes does not require a perldelta entry.

[bulk88]

sub blocking {
    my $sock = shift;
    return $sock->SUPER::blocking(@_)
        if $^O ne 'MSWin32' && $^O ne 'VMS';
# CUT comments
    my $orig= !${*$sock}{io_sock_nonblocking};
    return $orig unless @_;
    my $block = shift;
    if ( !$block != !$orig ) {
        ${*$sock}{io_sock_nonblocking} = $block ? 0 : 1;
        ioctl($sock, 0x8004667e, pack("L!",${*$sock}{io_sock_nonblocking})) #### <<<<< HERE
            or return undef;
    }
    return $orig;
}

Is there a COW/PADTMP problem with returned SVPV* of pp_pack() here? or a CPerlHost() vs win32_*() problem? win32.c has both a confusing win32_ioctl() and win32_ioctlsocket(), both goto winsock.dll in the end, but they have different func bodies.

[bulk88]

And Perl_pp_ioctl() needs a major CPP #if cleanup, it calls all the GV* IO* SVIV* SVUV* SVPV* and SvGROW() getters, allocers, and vivifiers, before calling Perl_die("fcntl is not implemented"); Perl_die("ioctl is not implemented");

[bulk88]

Git blame doesn't really explain the winsock char*/DWORD * "alignment" issue, but unresearched hypothesis, some frontend ware, middle ware, backend ware, or kernel ware (afd.sys) is stealing the lowest 2 or 3 bits for tagging, or afd.sys is SEGVing in Ring 0 attempting to read or write to that pointer. A SEH try/catch block in afd.sys silences/resumes/recovers from the bad CPU mem read or a bad NIC DMA memory read (bulk88 thinks # 2 isn't real, a PCIe NIC can't see or pull IP flow control/buffering logic on its own, its pushed to the NIC if it even participates in that).

/* XXX Why are APIs like sleep(), times() etc. inside a block
 * XXX guarded by "#ifndef WIN32IO_IS_STDIO"? */
#define ioctl			win32_ioctl
/////////CUT
#ifndef WIN32SCK_IS_STDSCK
/* direct to our version */
#define ioctlsocket	win32_ioctlsocket
/////////CUT
#  define PerlLIO_ioctl(fd, u, buf)     ioctl((fd), (u), (buf))
/////////CUT
#  define PerlLIO_ioctl(fd, u, buf)                                     \
        ((*(PL_LIO))->pIOCtl)(PL_LIO, (fd), (u), (buf))
/////////CUT
PP_wrapped(pp_ioctl, 3, 0) {
.............................
    if (optype == OP_IOCTL)
#ifdef HAS_IOCTL
        retval = PerlLIO_ioctl(PerlIO_fileno(IoIFP(io)), func, s);
#else
        DIE(aTHX_ "ioctl is not implemented");
#endif
/////////CUT
int win32_ioctlsocket(SOCKET s, long cmd, u_long *argp) {
    int r;
    SOCKET_TEST_ERROR(r = ioctlsocket(TO_SOCKET(s), cmd, argp));
    return r;
}
int win32_ioctl(int i, unsigned int u, char *data) {
    u_long u_long_arg; 
    int retval;
    /* mauke says using memcpy avoids alignment issues */
    memcpy(&u_long_arg, data, sizeof u_long_arg); 
    retval = ioctlsocket(TO_SOCKET(i), (long)u, &u_long_arg);
    memcpy(data, &u_long_arg, sizeof u_long_arg);
    if (retval == SOCKET_ERROR) {
        int wsaerr = WSAGetLastError();
        int err = convert_wsa_error_to_errno(wsaerr);
        if (err == ENOTSOCK) {
            Perl_croak_nocontext("ioctl implemented only on sockets");
            /* NOTREACHED */
        }
        errno = err;
        SetLastError(wsaerr);
    }
    return retval;
}
int
PerlSockIoctlsocket(const struct IPerlSock** piPerl, SOCKET s, long cmd, u_long *argp)
{
    PERL_UNUSED_ARG(piPerl);
    return win32_ioctlsocket(s, cmd, argp);
}
int PerlLIOIOCtl(const struct IPerlLIO** piPerl, int i, unsigned int u, char *data) {
    u_long u_long_arg;
    int retval;
    PERL_UNUSED_ARG(piPerl);
    /* mauke says using memcpy avoids alignment issues */
    memcpy(&u_long_arg, data, sizeof u_long_arg); 
    retval = win32_ioctlsocket((SOCKET)i, (long)u, &u_long_arg);
    memcpy(data, &u_long_arg, sizeof u_long_arg);
    return retval;
}