[perl5.git] / pp_sys.c

/*    pp_sys.c
 *
 *    Copyright (C) 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003,
 *    2004, 2005, 2006, 2007, 2008 by Larry Wall and others
 *
 *    You may distribute under the terms of either the GNU General Public
 *    License or the Artistic License, as specified in the README file.
 *
 */

/*
 * But only a short way ahead its floor and the walls on either side were
 * cloven by a great fissure, out of which the red glare came, now leaping
 * up, now dying down into darkness; and all the while far below there was
 * a rumour and a trouble as of great engines throbbing and labouring.
 *
 *     [p.945 of _The Lord of the Rings_, VI/iii: "Mount Doom"]
 */

/* This file contains system pp ("push/pop") functions that
 * execute the opcodes that make up a perl program. A typical pp function
 * expects to find its arguments on the stack, and usually pushes its
 * results onto the stack, hence the 'pp' terminology. Each OP structure
 * contains a pointer to the relevant pp_foo() function.
 *
 * By 'system', we mean ops which interact with the OS, such as pp_open().
 */

#include "EXTERN.h"
#define PERL_IN_PP_SYS_C
#include "perl.h"
#include "time64.h"
#include "time64.c"

#ifdef I_SHADOW
/* Shadow password support for solaris - pdo@cs.umd.edu
 * Not just Solaris: at least HP-UX, IRIX, Linux.
 * The API is from SysV.
 *
 * There are at least two more shadow interfaces,
 * see the comments in pp_gpwent().
 *
 * --jhi */
#   ifdef __hpux__
/* There is a MAXINT coming from <shadow.h> <- <hpsecurity.h> <- <values.h>
 * and another MAXINT from "perl.h" <- <sys/param.h>. */
#       undef MAXINT
#   endif
#   include <shadow.h>
#endif

#ifdef I_SYS_WAIT
# include <sys/wait.h>
#endif

#ifdef I_SYS_RESOURCE
# include <sys/resource.h>
#endif

#ifdef NETWARE
NETDB_DEFINE_CONTEXT
#endif

#ifdef HAS_SELECT
# ifdef I_SYS_SELECT
#  include <sys/select.h>
# endif
#endif

/* XXX Configure test needed.
   h_errno might not be a simple 'int', especially for multi-threaded
   applications, see "extern int errno in perl.h".  Creating such
   a test requires taking into account the differences between
   compiling multithreaded and singlethreaded ($ccflags et al).
   HOST_NOT_FOUND is typically defined in <netdb.h>.
*/
#if defined(HOST_NOT_FOUND) && !defined(h_errno) && !defined(__CYGWIN__)
extern int h_errno;
#endif

#ifdef HAS_PASSWD
# ifdef I_PWD
#  include <pwd.h>
# else
#  if !defined(VMS)
    struct passwd *getpwnam (char *);
    struct passwd *getpwuid (Uid_t);
#  endif
# endif
# ifdef HAS_GETPWENT
#ifndef getpwent
  struct passwd *getpwent (void);
#elif defined (VMS) && defined (my_getpwent)
  struct passwd *Perl_my_getpwent (pTHX);
#endif
# endif
#endif

#ifdef HAS_GROUP
# ifdef I_GRP
#  include <grp.h>
# else
    struct group *getgrnam (char *);
    struct group *getgrgid (Gid_t);
# endif
# ifdef HAS_GETGRENT
#ifndef getgrent
    struct group *getgrent (void);
#endif
# endif
#endif

#ifdef I_UTIME
#  if defined(_MSC_VER) || defined(__MINGW32__)
#    include <sys/utime.h>
#  else
#    include <utime.h>
#  endif
#endif

#ifdef HAS_CHSIZE
# ifdef my_chsize  /* Probably #defined to Perl_my_chsize in embed.h */
#   undef my_chsize
# endif
# define my_chsize PerlLIO_chsize
#else
# ifdef HAS_TRUNCATE
#   define my_chsize PerlLIO_chsize
# else
I32 my_chsize(int fd, Off_t length);
# endif
#endif

#ifdef HAS_FLOCK
#  define FLOCK flock
#else /* no flock() */

   /* fcntl.h might not have been included, even if it exists, because
      the current Configure only sets I_FCNTL if it's needed to pick up
      the *_OK constants.  Make sure it has been included before testing
      the fcntl() locking constants. */
#  if defined(HAS_FCNTL) && !defined(I_FCNTL)
#    include <fcntl.h>
#  endif

#  if defined(HAS_FCNTL) && defined(FCNTL_CAN_LOCK)
#    define FLOCK fcntl_emulate_flock
#    define FCNTL_EMULATE_FLOCK
#  else /* no flock() or fcntl(F_SETLK,...) */
#    ifdef HAS_LOCKF
#      define FLOCK lockf_emulate_flock
#      define LOCKF_EMULATE_FLOCK
#    endif /* lockf */
#  endif /* no flock() or fcntl(F_SETLK,...) */

#  ifdef FLOCK
     static int FLOCK (int, int);

    /*
     * These are the flock() constants.  Since this sytems doesn't have
     * flock(), the values of the constants are probably not available.
     */
#    ifndef LOCK_SH
#      define LOCK_SH 1
#    endif
#    ifndef LOCK_EX
#      define LOCK_EX 2
#    endif
#    ifndef LOCK_NB
#      define LOCK_NB 4
#    endif
#    ifndef LOCK_UN
#      define LOCK_UN 8
#    endif
#  endif /* emulating flock() */

#endif /* no flock() */

#define ZBTLEN 10
static const char zero_but_true[ZBTLEN + 1] = "0 but true";

#if defined(I_SYS_ACCESS) && !defined(R_OK)
#  include <sys/access.h>
#endif

#if defined(HAS_FCNTL) && defined(F_SETFD) && !defined(FD_CLOEXEC)
#  define FD_CLOEXEC 1		/* NeXT needs this */
#endif

#include "reentr.h"

#ifdef __Lynx__
/* Missing protos on LynxOS */
void sethostent(int);
void endhostent(void);
void setnetent(int);
void endnetent(void);
void setprotoent(int);
void endprotoent(void);
void setservent(int);
void endservent(void);
#endif

#undef PERL_EFF_ACCESS	/* EFFective uid/gid ACCESS */

/* F_OK unused: if stat() cannot find it... */

#if !defined(PERL_EFF_ACCESS) && defined(HAS_ACCESS) && defined(EFF_ONLY_OK) && !defined(NO_EFF_ONLY_OK)
    /* Digital UNIX (when the EFF_ONLY_OK gets fixed), UnixWare */
#   define PERL_EFF_ACCESS(p,f) (access((p), (f) | EFF_ONLY_OK))
#endif

#if !defined(PERL_EFF_ACCESS) && defined(HAS_EACCESS)
#   ifdef I_SYS_SECURITY
#       include <sys/security.h>
#   endif
#   ifdef ACC_SELF
        /* HP SecureWare */
#       define PERL_EFF_ACCESS(p,f) (eaccess((p), (f), ACC_SELF))
#   else
        /* SCO */
#       define PERL_EFF_ACCESS(p,f) (eaccess((p), (f)))
#   endif
#endif

#if !defined(PERL_EFF_ACCESS) && defined(HAS_ACCESSX) && defined(ACC_SELF)
    /* AIX */
#   define PERL_EFF_ACCESS(p,f) (accessx((p), (f), ACC_SELF))
#endif


#if !defined(PERL_EFF_ACCESS) && defined(HAS_ACCESS)	\
    && (defined(HAS_SETREUID) || defined(HAS_SETRESUID)		\
	|| defined(HAS_SETREGID) || defined(HAS_SETRESGID))
/* The Hard Way. */
STATIC int
S_emulate_eaccess(pTHX_ const char* path, Mode_t mode)
{
    const Uid_t ruid = getuid();
    const Uid_t euid = geteuid();
    const Gid_t rgid = getgid();
    const Gid_t egid = getegid();
    int res;

#if !defined(HAS_SETREUID) && !defined(HAS_SETRESUID)
    Perl_croak(aTHX_ "switching effective uid is not implemented");
#else
#ifdef HAS_SETREUID
    if (setreuid(euid, ruid))
#else
#ifdef HAS_SETRESUID
    if (setresuid(euid, ruid, (Uid_t)-1))
#endif
#endif
	Perl_croak(aTHX_ "entering effective uid failed");
#endif

#if !defined(HAS_SETREGID) && !defined(HAS_SETRESGID)
    Perl_croak(aTHX_ "switching effective gid is not implemented");
#else
#ifdef HAS_SETREGID
    if (setregid(egid, rgid))
#else
#ifdef HAS_SETRESGID
    if (setresgid(egid, rgid, (Gid_t)-1))
#endif
#endif
	Perl_croak(aTHX_ "entering effective gid failed");
#endif

    res = access(path, mode);

#ifdef HAS_SETREUID
    if (setreuid(ruid, euid))
#else
#ifdef HAS_SETRESUID
    if (setresuid(ruid, euid, (Uid_t)-1))
#endif
#endif
	Perl_croak(aTHX_ "leaving effective uid failed");

#ifdef HAS_SETREGID
    if (setregid(rgid, egid))
#else
#ifdef HAS_SETRESGID
    if (setresgid(rgid, egid, (Gid_t)-1))
#endif
#endif
	Perl_croak(aTHX_ "leaving effective gid failed");

    return res;
}
#   define PERL_EFF_ACCESS(p,f) (S_emulate_eaccess(aTHX_ (p), (f)))
#endif

PP(pp_backtick)
{
    dVAR; dSP; dTARGET;
    PerlIO *fp;
    const char * const tmps = POPpconstx;
    const I32 gimme = GIMME_V;
    const char *mode = "r";

    TAINT_PROPER("``");
    if (PL_op->op_private & OPpOPEN_IN_RAW)
	mode = "rb";
    else if (PL_op->op_private & OPpOPEN_IN_CRLF)
	mode = "rt";
    fp = PerlProc_popen(tmps, mode);
    if (fp) {
        const char * const type = Perl_PerlIO_context_layers(aTHX_ NULL);
	if (type && *type)
	    PerlIO_apply_layers(aTHX_ fp,mode,type);

	if (gimme == G_VOID) {
	    char tmpbuf[256];
	    while (PerlIO_read(fp, tmpbuf, sizeof tmpbuf) > 0)
		NOOP;
	}
	else if (gimme == G_SCALAR) {
	    ENTER_with_name("backtick");
	    SAVESPTR(PL_rs);
	    PL_rs = &PL_sv_undef;
	    sv_setpvs(TARG, "");	/* note that this preserves previous buffer */
	    while (sv_gets(TARG, fp, SvCUR(TARG)) != NULL)
		NOOP;
	    LEAVE_with_name("backtick");
	    XPUSHs(TARG);
	    SvTAINTED_on(TARG);
	}
	else {
	    for (;;) {
		SV * const sv = newSV(79);
		if (sv_gets(sv, fp, 0) == NULL) {
		    SvREFCNT_dec(sv);
		    break;
		}
		mXPUSHs(sv);
		if (SvLEN(sv) - SvCUR(sv) > 20) {
		    SvPV_shrink_to_cur(sv);
		}
		SvTAINTED_on(sv);
	    }
	}
	STATUS_NATIVE_CHILD_SET(PerlProc_pclose(fp));
	TAINT;		/* "I believe that this is not gratuitous!" */
    }
    else {
	STATUS_NATIVE_CHILD_SET(-1);
	if (gimme == G_SCALAR)
	    RETPUSHUNDEF;
    }

    RETURN;
}

PP(pp_glob)
{
    dVAR;
    OP *result;
    dSP;
    /* make a copy of the pattern, to ensure that magic is called once
     * and only once */
    TOPm1s = sv_2mortal(newSVsv(TOPm1s));

    tryAMAGICunTARGET(iter_amg, -1, (PL_op->op_flags & OPf_SPECIAL));

    if (PL_op->op_flags & OPf_SPECIAL) {
	/* call Perl-level glob function instead. Stack args are:
	 * MARK, wildcard, csh_glob context index
	 * and following OPs should be: gv(CORE::GLOBAL::glob), entersub
	 * */
	return NORMAL;
    }
    /* stack args are: wildcard, gv(_GEN_n) */


    /* Note that we only ever get here if File::Glob fails to load
     * without at the same time croaking, for some reason, or if
     * perl was built with PERL_EXTERNAL_GLOB */

    ENTER_with_name("glob");

#ifndef VMS
    if (PL_tainting) {
	/*
	 * The external globbing program may use things we can't control,
	 * so for security reasons we must assume the worst.
	 */
	TAINT;
	taint_proper(PL_no_security, "glob");
    }
#endif /* !VMS */

    SAVESPTR(PL_last_in_gv);	/* We don't want this to be permanent. */
    PL_last_in_gv = MUTABLE_GV(*PL_stack_sp--);

    SAVESPTR(PL_rs);		/* This is not permanent, either. */
    PL_rs = newSVpvs_flags("\000", SVs_TEMP);
#ifndef DOSISH
#ifndef CSH
    *SvPVX(PL_rs) = '\n';
#endif	/* !CSH */
#endif	/* !DOSISH */

    result = do_readline();
    LEAVE_with_name("glob");
    return result;
}

PP(pp_rcatline)
{
    dVAR;
    PL_last_in_gv = cGVOP_gv;
    return do_readline();
}

PP(pp_warn)
{
    dVAR; dSP; dMARK;
    SV *exsv;
    const char *pv;
    STRLEN len;
    if (SP - MARK > 1) {
	dTARGET;
	do_join(TARG, &PL_sv_no, MARK, SP);
	exsv = TARG;
	SP = MARK + 1;
    }
    else if (SP == MARK) {
	exsv = &PL_sv_no;
	EXTEND(SP, 1);
	SP = MARK + 1;
    }
    else {
	exsv = TOPs;
    }

    if (SvROK(exsv) || (pv = SvPV_const(exsv, len), len)) {
	/* well-formed exception supplied */
    }
    else if (SvROK(ERRSV)) {
	exsv = ERRSV;
    }
    else if (SvPOK(ERRSV) && SvCUR(ERRSV)) {
	exsv = sv_mortalcopy(ERRSV);
	sv_catpvs(exsv, "\t...caught");
    }
    else {
	exsv = newSVpvs_flags("Warning: something's wrong", SVs_TEMP);
    }
    warn_sv(exsv);
    RETSETYES;
}

PP(pp_die)
{
    dVAR; dSP; dMARK;
    SV *exsv;
    const char *pv;
    STRLEN len;
#ifdef VMS
    VMSISH_HUSHED  = VMSISH_HUSHED || (PL_op->op_private & OPpHUSH_VMSISH);
#endif
    if (SP - MARK != 1) {
	dTARGET;
	do_join(TARG, &PL_sv_no, MARK, SP);
	exsv = TARG;
	SP = MARK + 1;
    }
    else {
	exsv = TOPs;
    }

    if (SvROK(exsv) || (pv = SvPV_const(exsv, len), len)) {
	/* well-formed exception supplied */
    }
    else if (SvROK(ERRSV)) {
	exsv = ERRSV;
	if (sv_isobject(exsv)) {
	    HV * const stash = SvSTASH(SvRV(exsv));
	    GV * const gv = gv_fetchmethod(stash, "PROPAGATE");
	    if (gv) {
		SV * const file = sv_2mortal(newSVpv(CopFILE(PL_curcop),0));
		SV * const line = sv_2mortal(newSVuv(CopLINE(PL_curcop)));
		EXTEND(SP, 3);
		PUSHMARK(SP);
		PUSHs(exsv);
		PUSHs(file);
		PUSHs(line);
		PUTBACK;
		call_sv(MUTABLE_SV(GvCV(gv)),
			G_SCALAR|G_EVAL|G_KEEPERR);
		exsv = sv_mortalcopy(*PL_stack_sp--);
	    }
	}
    }
    else if (SvPOK(ERRSV) && SvCUR(ERRSV)) {
	exsv = sv_mortalcopy(ERRSV);
	sv_catpvs(exsv, "\t...propagated");
    }
    else {
	exsv = newSVpvs_flags("Died", SVs_TEMP);
    }
    return die_sv(exsv);
}

/* I/O. */

/* These are private to this function, which is private to this file.
   Use 0x04 rather than the next available bit, to help the compiler if the
   architecture can generate more efficient instructions.  */
#define MORTALIZE_NOT_NEEDED	0x04
#define ARGUMENTS_ON_STACK	0x08

static OP *
S_tied_handle_method(pTHX_ const char *const methname, SV **sp,
		     IO *const io, MAGIC *const mg, const U32 flags, U32 argc,
		     ...)
{
    PERL_ARGS_ASSERT_TIED_HANDLE_METHOD;

    /* Ensure that our flag bits do not overlap.  */
    assert((MORTALIZE_NOT_NEEDED & G_WANT) == 0);
    assert((ARGUMENTS_ON_STACK & G_WANT) == 0);

    PUSHMARK(sp);
    PUSHs(SvTIED_obj(MUTABLE_SV(io), mg));
    if (flags & ARGUMENTS_ON_STACK)
	sp += argc;
    else if (argc) {
	const U32 mortalize_not_needed = flags & MORTALIZE_NOT_NEEDED;
	va_list args;
	va_start(args, argc);
	do {
	    SV *const arg = va_arg(args, SV *);
	    if(mortalize_not_needed)
		PUSHs(arg);
	    else
		mPUSHs(arg);
	} while (--argc);
	va_end(args);
    }

    PUTBACK;
    ENTER_with_name("call_tied_handle_method");
    call_method(methname, flags & G_WANT);
    LEAVE_with_name("call_tied_handle_method");
    return NORMAL;
}

#define tied_handle_method(a,b,c,d)		\
    S_tied_handle_method(aTHX_ a,b,c,d,G_SCALAR,0)
#define tied_handle_method1(a,b,c,d,e)		\
    S_tied_handle_method(aTHX_ a,b,c,d,G_SCALAR,1,e)
#define tied_handle_method2(a,b,c,d,e,f)	\
    S_tied_handle_method(aTHX_ a,b,c,d,G_SCALAR,2,e,f)

PP(pp_open)
{
    dVAR; dSP;
    dMARK; dORIGMARK;
    dTARGET;
    SV *sv;
    IO *io;
    const char *tmps;
    STRLEN len;
    bool  ok;

    GV * const gv = MUTABLE_GV(*++MARK);

    if (!isGV(gv) && !(SvTYPE(gv) == SVt_PVLV && isGV_with_GP(gv)))
	DIE(aTHX_ PL_no_usym, "filehandle");

    if ((io = GvIOp(gv))) {
	MAGIC *mg;
	IoFLAGS(GvIOp(gv)) &= ~IOf_UNTAINT;

	if (IoDIRP(io))
	    Perl_ck_warner_d(aTHX_ packWARN2(WARN_IO, WARN_DEPRECATED),
			     "Opening dirhandle %s also as a file",
			     GvENAME(gv));

	mg = SvTIED_mg((const SV *)io, PERL_MAGIC_tiedscalar);
	if (mg) {
	    /* Method's args are same as ours ... */
	    /* ... except handle is replaced by the object */
	    return S_tied_handle_method(aTHX_ "OPEN", mark - 1, io, mg,
					G_SCALAR | ARGUMENTS_ON_STACK,
					sp - mark);
	}
    }

    if (MARK < SP) {
	sv = *++MARK;
    }
    else {
	sv = GvSVn(gv);
    }

    tmps = SvPV_const(sv, len);
    ok = do_openn(gv, tmps, len, FALSE, O_RDONLY, 0, NULL, MARK+1, (SP-MARK));
    SP = ORIGMARK;
    if (ok)
	PUSHi( (I32)PL_forkprocess );
    else if (PL_forkprocess == 0)		/* we are a new child */
	PUSHi(0);
    else
	RETPUSHUNDEF;
    RETURN;
}

PP(pp_close)
{
    dVAR; dSP;
    GV * const gv = (MAXARG == 0) ? PL_defoutgv : MUTABLE_GV(POPs);

    if (MAXARG == 0)
	EXTEND(SP, 1);

    if (gv) {
	IO * const io = GvIO(gv);
	if (io) {
	    MAGIC * const mg = SvTIED_mg((const SV *)io, PERL_MAGIC_tiedscalar);
	    if (mg) {
		return tied_handle_method("CLOSE", SP, io, mg);
	    }
	}
    }
    PUSHs(boolSV(do_close(gv, TRUE)));
    RETURN;
}

PP(pp_pipe_op)
{
#ifdef HAS_PIPE
    dVAR;
    dSP;
    register IO *rstio;
    register IO *wstio;
    int fd[2];

    GV * const wgv = MUTABLE_GV(POPs);
    GV * const rgv = MUTABLE_GV(POPs);

    if (!rgv || !wgv)
	goto badexit;

    if (!isGV_with_GP(rgv) || !isGV_with_GP(wgv))
	DIE(aTHX_ PL_no_usym, "filehandle");
    rstio = GvIOn(rgv);
    wstio = GvIOn(wgv);

    if (IoIFP(rstio))
	do_close(rgv, FALSE);
    if (IoIFP(wstio))
	do_close(wgv, FALSE);

    if (PerlProc_pipe(fd) < 0)
	goto badexit;

    IoIFP(rstio) = PerlIO_fdopen(fd[0], "r"PIPE_OPEN_MODE);
    IoOFP(wstio) = PerlIO_fdopen(fd[1], "w"PIPE_OPEN_MODE);
    IoOFP(rstio) = IoIFP(rstio);
    IoIFP(wstio) = IoOFP(wstio);
    IoTYPE(rstio) = IoTYPE_RDONLY;
    IoTYPE(wstio) = IoTYPE_WRONLY;

    if (!IoIFP(rstio) || !IoOFP(wstio)) {
	if (IoIFP(rstio))
	    PerlIO_close(IoIFP(rstio));
	else
	    PerlLIO_close(fd[0]);
	if (IoOFP(wstio))
	    PerlIO_close(IoOFP(wstio));
	else
	    PerlLIO_close(fd[1]);
	goto badexit;
    }
#if defined(HAS_FCNTL) && defined(F_SETFD)
    fcntl(fd[0],F_SETFD,fd[0] > PL_maxsysfd);	/* ensure close-on-exec */
    fcntl(fd[1],F_SETFD,fd[1] > PL_maxsysfd);	/* ensure close-on-exec */
#endif
    RETPUSHYES;

badexit:
    RETPUSHUNDEF;
#else
    DIE(aTHX_ PL_no_func, "pipe");
#endif
}

PP(pp_fileno)
{
    dVAR; dSP; dTARGET;
    GV *gv;
    IO *io;
    PerlIO *fp;
    MAGIC  *mg;

    if (MAXARG < 1)
	RETPUSHUNDEF;
    gv = MUTABLE_GV(POPs);
    io = GvIO(gv);

    if (io
	&& (mg = SvTIED_mg((const SV *)io, PERL_MAGIC_tiedscalar)))
    {
	return tied_handle_method("FILENO", SP, io, mg);
    }

    if (!io || !(fp = IoIFP(io))) {
	/* Can't do this because people seem to do things like
	   defined(fileno($foo)) to check whether $foo is a valid fh.

	   report_evil_fh(gv);
	    */
	RETPUSHUNDEF;
    }

    PUSHi(PerlIO_fileno(fp));
    RETURN;
}

PP(pp_umask)
{
    dVAR;
    dSP;
#ifdef HAS_UMASK
    dTARGET;
    Mode_t anum;

    if (MAXARG < 1) {
	anum = PerlLIO_umask(022);
	/* setting it to 022 between the two calls to umask avoids
	 * to have a window where the umask is set to 0 -- meaning
	 * that another thread could create world-writeable files. */
	if (anum != 022)
	    (void)PerlLIO_umask(anum);
    }
    else
	anum = PerlLIO_umask(POPi);
    TAINT_PROPER("umask");
    XPUSHi(anum);
#else
    /* Only DIE if trying to restrict permissions on "user" (self).
     * Otherwise it's harmless and more useful to just return undef
     * since 'group' and 'other' concepts probably don't exist here. */
    if (MAXARG >= 1 && (POPi & 0700))
	DIE(aTHX_ "umask not implemented");
    XPUSHs(&PL_sv_undef);
#endif
    RETURN;
}

PP(pp_binmode)
{
    dVAR; dSP;
    GV *gv;
    IO *io;
    PerlIO *fp;
    SV *discp = NULL;

    if (MAXARG < 1)
	RETPUSHUNDEF;
    if (MAXARG > 1) {
	discp = POPs;
    }

    gv = MUTABLE_GV(POPs);
    io = GvIO(gv);

    if (io) {
	MAGIC * const mg = SvTIED_mg((const SV *)io, PERL_MAGIC_tiedscalar);
	if (mg) {
	    /* This takes advantage of the implementation of the varargs
	       function, which I don't think that the optimiser will be able to
	       figure out. Although, as it's a static function, in theory it
	       could.  */
	    return S_tied_handle_method(aTHX_ "BINMODE", SP, io, mg,
					G_SCALAR|MORTALIZE_NOT_NEEDED,
					discp ? 1 : 0, discp);
	}
    }

    if (!io || !(fp = IoIFP(io))) {
	report_evil_fh(gv);
	SETERRNO(EBADF,RMS_IFI);
        RETPUSHUNDEF;
    }

    PUTBACK;
    {
	STRLEN len = 0;
	const char *d = NULL;
	int mode;
	if (discp)
	    d = SvPV_const(discp, len);
	mode = mode_from_discipline(d, len);
	if (PerlIO_binmode(aTHX_ fp, IoTYPE(io), mode, d)) {
	    if (IoOFP(io) && IoOFP(io) != IoIFP(io)) {
		if (!PerlIO_binmode(aTHX_ IoOFP(io), IoTYPE(io), mode, d)) {
		    SPAGAIN;
		    RETPUSHUNDEF;
		}
	    }
	    SPAGAIN;
	    RETPUSHYES;
	}
	else {
	    SPAGAIN;
	    RETPUSHUNDEF;
	}
    }
}

PP(pp_tie)
{
    dVAR; dSP; dMARK;
    HV* stash;
    GV *gv = NULL;
    SV *sv;
    const I32 markoff = MARK - PL_stack_base;
    const char *methname;
    int how = PERL_MAGIC_tied;
    U32 items;
    SV *varsv = *++MARK;

    switch(SvTYPE(varsv)) {
	case SVt_PVHV:
	    methname = "TIEHASH";
	    HvEITER_set(MUTABLE_HV(varsv), 0);
	    break;
	case SVt_PVAV:
	    methname = "TIEARRAY";
	    break;
	case SVt_PVGV:
	case SVt_PVLV:
	    if (isGV_with_GP(varsv)) {
		if (SvFAKE(varsv) && !(GvFLAGS(varsv) & GVf_TIEWARNED)) {
		    deprecate("tie on a handle without *");
		    GvFLAGS(varsv) |= GVf_TIEWARNED;
		}
		methname = "TIEHANDLE";
		how = PERL_MAGIC_tiedscalar;
		/* For tied filehandles, we apply tiedscalar magic to the IO
		   slot of the GP rather than the GV itself. AMS 20010812 */
		if (!GvIOp(varsv))
		    GvIOp(varsv) = newIO();
		varsv = MUTABLE_SV(GvIOp(varsv));
		break;
	    }
	    /* FALL THROUGH */
	default:
	    methname = "TIESCALAR";
	    how = PERL_MAGIC_tiedscalar;
	    break;
    }
    items = SP - MARK++;
    if (sv_isobject(*MARK)) { /* Calls GET magic. */
	ENTER_with_name("call_TIE");
	PUSHSTACKi(PERLSI_MAGIC);
	PUSHMARK(SP);
	EXTEND(SP,(I32)items);
	while (items--)
	    PUSHs(*MARK++);
	PUTBACK;
	call_method(methname, G_SCALAR);
    }
    else {
	/* Can't use call_method here, else this: fileno FOO; tie @a, "FOO"
	 * will attempt to invoke IO::File::TIEARRAY, with (best case) the
	 * wrong error message, and worse case, supreme action at a distance.
	 * (Sorry obfuscation writers. You're not going to be given this one.)
	 */
	STRLEN len;
	const char *name = SvPV_nomg_const(*MARK, len);
	stash = gv_stashpvn(name, len, 0);
	if (!stash || !(gv = gv_fetchmethod(stash, methname))) {
	    DIE(aTHX_ "Can't locate object method \"%s\" via package \"%"SVf"\"",
		 methname, SVfARG(SvOK(*MARK) ? *MARK : &PL_sv_no));
	}
	ENTER_with_name("call_TIE");
	PUSHSTACKi(PERLSI_MAGIC);
	PUSHMARK(SP);
	EXTEND(SP,(I32)items);
	while (items--)
	    PUSHs(*MARK++);
	PUTBACK;
	call_sv(MUTABLE_SV(GvCV(gv)), G_SCALAR);
    }
    SPAGAIN;

    sv = TOPs;
    POPSTACK;
    if (sv_isobject(sv)) {
	sv_unmagic(varsv, how);
	/* Croak if a self-tie on an aggregate is attempted. */
	if (varsv == SvRV(sv) &&
	    (SvTYPE(varsv) == SVt_PVAV ||
	     SvTYPE(varsv) == SVt_PVHV))
	    Perl_croak(aTHX_
		       "Self-ties of arrays and hashes are not supported");
	sv_magic(varsv, (SvRV(sv) == varsv ? NULL : sv), how, NULL, 0);
    }
    LEAVE_with_name("call_TIE");
    SP = PL_stack_base + markoff;
    PUSHs(sv);
    RETURN;
}

PP(pp_untie)
{
    dVAR; dSP;
    MAGIC *mg;
    SV *sv = POPs;
    const char how = (SvTYPE(sv) == SVt_PVHV || SvTYPE(sv) == SVt_PVAV)
		? PERL_MAGIC_tied : PERL_MAGIC_tiedscalar;

    if (isGV_with_GP(sv)) {
      if (SvFAKE(sv) && !(GvFLAGS(sv) & GVf_TIEWARNED)) {
	deprecate("untie on a handle without *");
	GvFLAGS(sv) |= GVf_TIEWARNED;
      }
      if (!(sv = MUTABLE_SV(GvIOp(sv))))
	RETPUSHYES;
    }

    if ((mg = SvTIED_mg(sv, how))) {
	SV * const obj = SvRV(SvTIED_obj(sv, mg));
        if (obj) {
	    GV * const gv = gv_fetchmethod_autoload(SvSTASH(obj), "UNTIE", FALSE);
	    CV *cv;
	    if (gv && isGV(gv) && (cv = GvCV(gv))) {
	       PUSHMARK(SP);
	       PUSHs(SvTIED_obj(MUTABLE_SV(gv), mg));
	       mXPUSHi(SvREFCNT(obj) - 1);
	       PUTBACK;
	       ENTER_with_name("call_UNTIE");
	       call_sv(MUTABLE_SV(cv), G_VOID);
	       LEAVE_with_name("call_UNTIE");
	       SPAGAIN;
            }
	    else if (mg && SvREFCNT(obj) > 1) {
		Perl_ck_warner(aTHX_ packWARN(WARN_UNTIE),
			       "untie attempted while %"UVuf" inner references still exist",
			       (UV)SvREFCNT(obj) - 1 ) ;
	    }
        }
    }
    sv_unmagic(sv, how) ;
    RETPUSHYES;
}

PP(pp_tied)
{
    dVAR;
    dSP;
    const MAGIC *mg;
    SV *sv = POPs;
    const char how = (SvTYPE(sv) == SVt_PVHV || SvTYPE(sv) == SVt_PVAV)
		? PERL_MAGIC_tied : PERL_MAGIC_tiedscalar;

    if (isGV_with_GP(sv)) {
      if (SvFAKE(sv) && !(GvFLAGS(sv) & GVf_TIEWARNED)) {
	deprecate("tied on a handle without *");
	GvFLAGS(sv) |= GVf_TIEWARNED;
      }
      if (!(sv = MUTABLE_SV(GvIOp(sv))))
	RETPUSHUNDEF;
    }

    if ((mg = SvTIED_mg(sv, how))) {
	SV *osv = SvTIED_obj(sv, mg);
	if (osv == mg->mg_obj)
	    osv = sv_mortalcopy(osv);
	PUSHs(osv);
	RETURN;
    }
    RETPUSHUNDEF;
}

PP(pp_dbmopen)
{
    dVAR; dSP;
    dPOPPOPssrl;
    HV* stash;
    GV *gv = NULL;

    HV * const hv = MUTABLE_HV(POPs);
    SV * const sv = newSVpvs_flags("AnyDBM_File", SVs_TEMP);
    stash = gv_stashsv(sv, 0);
    if (!stash || !(gv = gv_fetchmethod(stash, "TIEHASH"))) {
	PUTBACK;
	require_pv("AnyDBM_File.pm");
	SPAGAIN;
	if (!stash || !(gv = gv_fetchmethod(stash, "TIEHASH")))
	    DIE(aTHX_ "No dbm on this machine");
    }

    ENTER;
    PUSHMARK(SP);

    EXTEND(SP, 5);
    PUSHs(sv);
    PUSHs(left);
    if (SvIV(right))
	mPUSHu(O_RDWR|O_CREAT);
    else
	mPUSHu(O_RDWR);
    PUSHs(right);
    PUTBACK;
    call_sv(MUTABLE_SV(GvCV(gv)), G_SCALAR);
    SPAGAIN;

    if (!sv_isobject(TOPs)) {
	SP--;
	PUSHMARK(SP);
	PUSHs(sv);
	PUSHs(left);
	mPUSHu(O_RDONLY);
	PUSHs(right);
	PUTBACK;
	call_sv(MUTABLE_SV(GvCV(gv)), G_SCALAR);
	SPAGAIN;
    }

    if (sv_isobject(TOPs)) {
	sv_unmagic(MUTABLE_SV(hv), PERL_MAGIC_tied);
	sv_magic(MUTABLE_SV(hv), TOPs, PERL_MAGIC_tied, NULL, 0);
    }
    LEAVE;
    RETURN;
}

PP(pp_sselect)
{
#ifdef HAS_SELECT
    dVAR; dSP; dTARGET;
    register I32 i;
    register I32 j;
    register char *s;
    register SV *sv;
    NV value;
    I32 maxlen = 0;
    I32 nfound;
    struct timeval timebuf;
    struct timeval *tbuf = &timebuf;
    I32 growsize;
    char *fd_sets[4];
#if BYTEORDER != 0x1234 && BYTEORDER != 0x12345678
	I32 masksize;
	I32 offset;
	I32 k;

#   if BYTEORDER & 0xf0000
#	define ORDERBYTE (0x88888888 - BYTEORDER)
#   else
#	define ORDERBYTE (0x4444 - BYTEORDER)
#   endif

#endif

    SP -= 4;
    for (i = 1; i <= 3; i++) {
	SV * const sv = SP[i];
	if (!SvOK(sv))
	    continue;
	if (SvREADONLY(sv)) {
	    if (SvIsCOW(sv))
		sv_force_normal_flags(sv, 0);
	    if (SvREADONLY(sv) && !(SvPOK(sv) && SvCUR(sv) == 0))
		Perl_croak_no_modify(aTHX);
	}
	if (!SvPOK(sv)) {
	    Perl_ck_warner(aTHX_ packWARN(WARN_MISC), "Non-string passed as bitmask");
	    SvPV_force_nolen(sv);	/* force string conversion */
	}
	j = SvCUR(sv);
	if (maxlen < j)
	    maxlen = j;
    }

/* little endians can use vecs directly */
#if BYTEORDER != 0x1234 && BYTEORDER != 0x12345678
#  ifdef NFDBITS

#    ifndef NBBY
#     define NBBY 8
#    endif

    masksize = NFDBITS / NBBY;
#  else
    masksize = sizeof(long);	/* documented int, everyone seems to use long */
#  endif
    Zero(&fd_sets[0], 4, char*);
#endif

#  if SELECT_MIN_BITS == 1
    growsize = sizeof(fd_set);
#  else
#   if defined(__GLIBC__) && defined(__FD_SETSIZE)
#      undef SELECT_MIN_BITS
#      define SELECT_MIN_BITS __FD_SETSIZE
#   endif
    /* If SELECT_MIN_BITS is greater than one we most probably will want
     * to align the sizes with SELECT_MIN_BITS/8 because for example
     * in many little-endian (Intel, Alpha) systems (Linux, OS/2, Digital
     * UNIX, Solaris, NeXT, Darwin) the smallest quantum select() operates
     * on (sets/tests/clears bits) is 32 bits.  */
    growsize = maxlen + (SELECT_MIN_BITS/8 - (maxlen % (SELECT_MIN_BITS/8)));
#  endif

    sv = SP[4];
    if (SvOK(sv)) {
	value = SvNV(sv);
	if (value < 0.0)
	    value = 0.0;
	timebuf.tv_sec = (long)value;
	value -= (NV)timebuf.tv_sec;
	timebuf.tv_usec = (long)(value * 1000000.0);
    }
    else
	tbuf = NULL;

    for (i = 1; i <= 3; i++) {
	sv = SP[i];
	if (!SvOK(sv) || SvCUR(sv) == 0) {
	    fd_sets[i] = 0;
	    continue;
	}
	assert(SvPOK(sv));
	j = SvLEN(sv);
	if (j < growsize) {
	    Sv_Grow(sv, growsize);
	}
	j = SvCUR(sv);
	s = SvPVX(sv) + j;
	while (++j <= growsize) {
	    *s++ = '\0';
	}

#if BYTEORDER != 0x1234 && BYTEORDER != 0x12345678
	s = SvPVX(sv);
	Newx(fd_sets[i], growsize, char);
	for (offset = 0; offset < growsize; offset += masksize) {
	    for (j = 0, k=ORDERBYTE; j < masksize; j++, (k >>= 4))
		fd_sets[i][j+offset] = s[(k % masksize) + offset];
	}
#else
	fd_sets[i] = SvPVX(sv);
#endif
    }

#ifdef PERL_IRIX5_SELECT_TIMEVAL_VOID_CAST
    /* Can't make just the (void*) conditional because that would be
     * cpp #if within cpp macro, and not all compilers like that. */
    nfound = PerlSock_select(
	maxlen * 8,
	(Select_fd_set_t) fd_sets[1],
	(Select_fd_set_t) fd_sets[2],
	(Select_fd_set_t) fd_sets[3],
	(void*) tbuf); /* Workaround for compiler bug. */
#else
    nfound = PerlSock_select(
	maxlen * 8,
	(Select_fd_set_t) fd_sets[1],
	(Select_fd_set_t) fd_sets[2],
	(Select_fd_set_t) fd_sets[3],
	tbuf);
#endif
    for (i = 1; i <= 3; i++) {
	if (fd_sets[i]) {
	    sv = SP[i];
#if BYTEORDER != 0x1234 && BYTEORDER != 0x12345678
	    s = SvPVX(sv);
	    for (offset = 0; offset < growsize; offset += masksize) {
		for (j = 0, k=ORDERBYTE; j < masksize; j++, (k >>= 4))
		    s[(k % masksize) + offset] = fd_sets[i][j+offset];
	    }
	    Safefree(fd_sets[i]);
#endif
	    SvSETMAGIC(sv);
	}
    }

    PUSHi(nfound);
    if (GIMME == G_ARRAY && tbuf) {
	value = (NV)(timebuf.tv_sec) +
		(NV)(timebuf.tv_usec) / 1000000.0;
	mPUSHn(value);
    }
    RETURN;
#else
    DIE(aTHX_ "select not implemented");
#endif
}

/*
=for apidoc setdefout

Sets PL_defoutgv, the default file handle for output, to the passed in
typeglob. As PL_defoutgv "owns" a reference on its typeglob, the reference
count of the passed in typeglob is increased by one, and the reference count
of the typeglob that PL_defoutgv points to is decreased by one.

=cut
*/

void
Perl_setdefout(pTHX_ GV *gv)
{
    dVAR;
    SvREFCNT_inc_simple_void(gv);
    SvREFCNT_dec(PL_defoutgv);
    PL_defoutgv = gv;
}

PP(pp_select)
{
    dVAR; dSP; dTARGET;
    HV *hv;
    GV * const newdefout = (PL_op->op_private > 0) ? (MUTABLE_GV(POPs)) : NULL;
    GV * egv = GvEGVx(PL_defoutgv);

    if (!egv)
	egv = PL_defoutgv;
    hv = isGV_with_GP(egv) ? GvSTASH(egv) : NULL;
    if (! hv)
	XPUSHs(&PL_sv_undef);
    else {
	GV * const * const gvp = (GV**)hv_fetch(hv, GvNAME(egv), GvNAMELEN(egv), FALSE);
	if (gvp && *gvp == egv) {
	    gv_efullname4(TARG, PL_defoutgv, NULL, TRUE);
	    XPUSHTARG;
	}
	else {
	    mXPUSHs(newRV(MUTABLE_SV(egv)));
	}
    }

    if (newdefout) {
	if (!GvIO(newdefout))
	    gv_IOadd(newdefout);
	setdefout(newdefout);
    }

    RETURN;
}

PP(pp_getc)
{
    dVAR; dSP; dTARGET;
    GV * const gv = (MAXARG==0) ? PL_stdingv : MUTABLE_GV(POPs);
    IO *const io = GvIO(gv);

    if (MAXARG == 0)
	EXTEND(SP, 1);

    if (io) {
	MAGIC * const mg = SvTIED_mg((const SV *)io, PERL_MAGIC_tiedscalar);
	if (mg) {
	    const U32 gimme = GIMME_V;
	    S_tied_handle_method(aTHX_ "GETC", SP, io, mg, gimme, 0);
	    if (gimme == G_SCALAR) {
		SPAGAIN;
		SvSetMagicSV_nosteal(TARG, TOPs);
	    }
	    return NORMAL;
	}
    }
    if (!gv || do_eof(gv)) { /* make sure we have fp with something */
	if (!io || (!IoIFP(io) && IoTYPE(io) != IoTYPE_WRONLY))
	    report_evil_fh(gv);
	SETERRNO(EBADF,RMS_IFI);
	RETPUSHUNDEF;
    }
    TAINT;
    sv_setpvs(TARG, " ");
    *SvPVX(TARG) = PerlIO_getc(IoIFP(GvIOp(gv))); /* should never be EOF */
    if (PerlIO_isutf8(IoIFP(GvIOp(gv)))) {
	/* Find out how many bytes the char needs */
	Size_t len = UTF8SKIP(SvPVX_const(TARG));
	if (len > 1) {
	    SvGROW(TARG,len+1);
	    len = PerlIO_read(IoIFP(GvIOp(gv)),SvPVX(TARG)+1,len-1);
	    SvCUR_set(TARG,1+len);
	}
	SvUTF8_on(TARG);
    }
    PUSHTARG;
    RETURN;
}

STATIC OP *
S_doform(pTHX_ CV *cv, GV *gv, OP *retop)
{
    dVAR;
    register PERL_CONTEXT *cx;
    const I32 gimme = GIMME_V;

    PERL_ARGS_ASSERT_DOFORM;

    if (cv && CvCLONE(cv))
	cv = MUTABLE_CV(sv_2mortal(MUTABLE_SV(cv_clone(cv))));

    ENTER;
    SAVETMPS;

    PUSHBLOCK(cx, CXt_FORMAT, PL_stack_sp);
    PUSHFORMAT(cx, retop);
    SAVECOMPPAD();
    PAD_SET_CUR_NOSAVE(CvPADLIST(cv), 1);

    setdefout(gv);	    /* locally select filehandle so $% et al work */
    return CvSTART(cv);
}

PP(pp_enterwrite)
{
    dVAR;
    dSP;
    register GV *gv;
    register IO *io;
    GV *fgv;
    CV *cv = NULL;
    SV *tmpsv = NULL;

    if (MAXARG == 0) {
	gv = PL_defoutgv;
	EXTEND(SP, 1);
    }
    else {
	gv = MUTABLE_GV(POPs);
	if (!gv)
	    gv = PL_defoutgv;
    }
    io = GvIO(gv);
    if (!io) {
	RETPUSHNO;
    }
    if (IoFMT_GV(io))
	fgv = IoFMT_GV(io);
    else
	fgv = gv;

    if (!fgv)
	goto not_a_format_reference;

    cv = GvFORM(fgv);
    if (!cv) {
	const char *name;
	tmpsv = sv_newmortal();
	gv_efullname4(tmpsv, fgv, NULL, FALSE);
	name = SvPV_nolen_const(tmpsv);
	if (name && *name)
	    DIE(aTHX_ "Undefined format \"%s\" called", name);

	not_a_format_reference:
	DIE(aTHX_ "Not a format reference");
    }
    IoFLAGS(io) &= ~IOf_DIDTOP;
    return doform(cv,gv,PL_op->op_next);
}

PP(pp_leavewrite)
{
    dVAR; dSP;
    GV * const gv = cxstack[cxstack_ix].blk_format.gv;
    register IO * const io = GvIOp(gv);
    PerlIO *ofp;
    PerlIO *fp;
    SV **newsp;
    I32 gimme;
    register PERL_CONTEXT *cx;
    OP *retop;

    if (!io || !(ofp = IoOFP(io)))
        goto forget_top;

    DEBUG_f(PerlIO_printf(Perl_debug_log, "left=%ld, todo=%ld\n",
	  (long)IoLINES_LEFT(io), (long)FmLINES(PL_formtarget)));

    if (IoLINES_LEFT(io) < FmLINES(PL_formtarget) &&
	PL_formtarget != PL_toptarget)
    {
	GV *fgv;
	CV *cv;
	if (!IoTOP_GV(io)) {
	    GV *topgv;

	    if (!IoTOP_NAME(io)) {
		SV *topname;
		if (!IoFMT_NAME(io))
		    IoFMT_NAME(io) = savepv(GvNAME(gv));
		topname = sv_2mortal(Perl_newSVpvf(aTHX_ "%s_TOP", GvNAME(gv)));
		topgv = gv_fetchsv(topname, 0, SVt_PVFM);
		if ((topgv && GvFORM(topgv)) ||
		  !gv_fetchpvs("top", GV_NOTQUAL, SVt_PVFM))
		    IoTOP_NAME(io) = savesvpv(topname);
		else
		    IoTOP_NAME(io) = savepvs("top");
	    }
	    topgv = gv_fetchpv(IoTOP_NAME(io), 0, SVt_PVFM);
	    if (!topgv || !GvFORM(topgv)) {
		IoLINES_LEFT(io) = IoPAGE_LEN(io);
		goto forget_top;
	    }
	    IoTOP_GV(io) = topgv;
	}
	if (IoFLAGS(io) & IOf_DIDTOP) {	/* Oh dear.  It still doesn't fit. */
	    I32 lines = IoLINES_LEFT(io);
	    const char *s = SvPVX_const(PL_formtarget);
	    if (lines <= 0)		/* Yow, header didn't even fit!!! */
		goto forget_top;
	    while (lines-- > 0) {
		s = strchr(s, '\n');
		if (!s)
		    break;
		s++;
	    }
	    if (s) {
		const STRLEN save = SvCUR(PL_formtarget);
		SvCUR_set(PL_formtarget, s - SvPVX_const(PL_formtarget));
		do_print(PL_formtarget, ofp);
		SvCUR_set(PL_formtarget, save);
		sv_chop(PL_formtarget, s);
		FmLINES(PL_formtarget) -= IoLINES_LEFT(io);
	    }
	}
	if (IoLINES_LEFT(io) >= 0 && IoPAGE(io) > 0)
	    do_print(PL_formfeed, ofp);
	IoLINES_LEFT(io) = IoPAGE_LEN(io);
	IoPAGE(io)++;
	PL_formtarget = PL_toptarget;
	IoFLAGS(io) |= IOf_DIDTOP;
	fgv = IoTOP_GV(io);
	if (!fgv)
	    DIE(aTHX_ "bad top format reference");
	cv = GvFORM(fgv);
	if (!cv) {
	    SV * const sv = sv_newmortal();
	    const char *name;
	    gv_efullname4(sv, fgv, NULL, FALSE);
	    name = SvPV_nolen_const(sv);
	    if (name && *name)
		DIE(aTHX_ "Undefined top format \"%s\" called", name);
	    else
		DIE(aTHX_ "Undefined top format called");
	}
	return doform(cv, gv, PL_op);
    }

  forget_top:
    POPBLOCK(cx,PL_curpm);
    POPFORMAT(cx);
    retop = cx->blk_sub.retop;
    LEAVE;

    fp = IoOFP(io);
    if (!fp) {
	if (IoIFP(io))
	    report_wrongway_fh(gv, '<');
	else
	    report_evil_fh(gv);
	PUSHs(&PL_sv_no);
    }
    else {
	if ((IoLINES_LEFT(io) -= FmLINES(PL_formtarget)) < 0) {
	    Perl_ck_warner(aTHX_ packWARN(WARN_IO), "page overflow");
	}
	if (!do_print(PL_formtarget, fp))
	    PUSHs(&PL_sv_no);
	else {
	    FmLINES(PL_formtarget) = 0;
	    SvCUR_set(PL_formtarget, 0);
	    *SvEND(PL_formtarget) = '\0';
	    if (IoFLAGS(io) & IOf_FLUSH)
		(void)PerlIO_flush(fp);
	    PUSHs(&PL_sv_yes);
	}
    }
    /* bad_ofp: */
    PL_formtarget = PL_bodytarget;
    PUTBACK;
    PERL_UNUSED_VAR(newsp);
    PERL_UNUSED_VAR(gimme);
    return retop;
}

PP(pp_prtf)
{
    dVAR; dSP; dMARK; dORIGMARK;
    PerlIO *fp;
    SV *sv;

    GV * const gv
	= (PL_op->op_flags & OPf_STACKED) ? MUTABLE_GV(*++MARK) : PL_defoutgv;
    IO *const io = GvIO(gv);

    if (io) {
	MAGIC * const mg = SvTIED_mg((const SV *)io, PERL_MAGIC_tiedscalar);
	if (mg) {
	    if (MARK == ORIGMARK) {
		MEXTEND(SP, 1);
		++MARK;
		Move(MARK, MARK + 1, (SP - MARK) + 1, SV*);
		++SP;
	    }
	    return S_tied_handle_method(aTHX_ "PRINTF", mark - 1, io, mg,
					G_SCALAR | ARGUMENTS_ON_STACK,
					sp - mark);
	}
    }

    sv = newSV(0);
    if (!io) {
	report_evil_fh(gv);
	SETERRNO(EBADF,RMS_IFI);
	goto just_say_no;
    }
    else if (!(fp = IoOFP(io))) {
	if (IoIFP(io))
	    report_wrongway_fh(gv, '<');
	else if (ckWARN(WARN_CLOSED))
	    report_evil_fh(gv);
	SETERRNO(EBADF,IoIFP(io)?RMS_FAC:RMS_IFI);
	goto just_say_no;
    }
    else {
	if (SvTAINTED(MARK[1]))
	    TAINT_PROPER("printf");
	do_sprintf(sv, SP - MARK, MARK + 1);
	if (!do_print(sv, fp))
	    goto just_say_no;

	if (IoFLAGS(io) & IOf_FLUSH)
	    if (PerlIO_flush(fp) == EOF)
		goto just_say_no;
    }
    SvREFCNT_dec(sv);
    SP = ORIGMARK;
    PUSHs(&PL_sv_yes);
    RETURN;

  just_say_no:
    SvREFCNT_dec(sv);
    SP = ORIGMARK;
    PUSHs(&PL_sv_undef);
    RETURN;
}

PP(pp_sysopen)
{
    dVAR;
    dSP;
    const int perm = (MAXARG > 3) ? POPi : 0666;
    const int mode = POPi;
    SV * const sv = POPs;
    GV * const gv = MUTABLE_GV(POPs);
    STRLEN len;

    /* Need TIEHANDLE method ? */
    const char * const tmps = SvPV_const(sv, len);
    /* FIXME? do_open should do const  */
    if (do_open(gv, tmps, len, TRUE, mode, perm, NULL)) {
	IoLINES(GvIOp(gv)) = 0;
	PUSHs(&PL_sv_yes);
    }
    else {
	PUSHs(&PL_sv_undef);
    }
    RETURN;
}

PP(pp_sysread)
{
    dVAR; dSP; dMARK; dORIGMARK; dTARGET;
    int offset;
    IO *io;
    char *buffer;
    SSize_t length;
    SSize_t count;
    Sock_size_t bufsize;
    SV *bufsv;
    STRLEN blen;
    int fp_utf8;
    int buffer_utf8;
    SV *read_target;
    Size_t got = 0;
    Size_t wanted;
    bool charstart = FALSE;
    STRLEN charskip = 0;
    STRLEN skip = 0;

    GV * const gv = MUTABLE_GV(*++MARK);
    if ((PL_op->op_type == OP_READ || PL_op->op_type == OP_SYSREAD)
	&& gv && (io = GvIO(gv)) )
    {
	MAGIC *const mg = SvTIED_mg((const SV *)io, PERL_MAGIC_tiedscalar);
	if (mg) {
	    return S_tied_handle_method(aTHX_ "READ", mark - 1, io, mg,
					G_SCALAR | ARGUMENTS_ON_STACK,
					sp - mark);
	}
    }

    if (!gv)
	goto say_undef;
    bufsv = *++MARK;
    if (! SvOK(bufsv))
	sv_setpvs(bufsv, "");
    length = SvIVx(*++MARK);
    SETERRNO(0,0);
    if (MARK < SP)
	offset = SvIVx(*++MARK);
    else
	offset = 0;
    io = GvIO(gv);
    if (!io || !IoIFP(io)) {
	report_evil_fh(gv);
	SETERRNO(EBADF,RMS_IFI);
	goto say_undef;
    }
    if ((fp_utf8 = PerlIO_isutf8(IoIFP(io))) && !IN_BYTES) {
	buffer = SvPVutf8_force(bufsv, blen);
	/* UTF-8 may not have been set if they are all low bytes */
	SvUTF8_on(bufsv);
	buffer_utf8 = 0;
    }
    else {
	buffer = SvPV_force(bufsv, blen);
	buffer_utf8 = !IN_BYTES && SvUTF8(bufsv);
    }
    if (length < 0)
	DIE(aTHX_ "Negative length");
    wanted = length;

    charstart = TRUE;
    charskip  = 0;
    skip = 0;

#ifdef HAS_SOCKET
    if (PL_op->op_type == OP_RECV) {
	char namebuf[MAXPATHLEN];
#if (defined(VMS_DO_SOCKETS) && defined(DECCRTL_SOCKETS)) || defined(MPE) || defined(__QNXNTO__)
	bufsize = sizeof (struct sockaddr_in);
#else
	bufsize = sizeof namebuf;
#endif
#ifdef OS2	/* At least Warp3+IAK: only the first byte of bufsize set */
	if (bufsize >= 256)
	    bufsize = 255;
#endif
	buffer = SvGROW(bufsv, (STRLEN)(length+1));
	/* 'offset' means 'flags' here */
	count = PerlSock_recvfrom(PerlIO_fileno(IoIFP(io)), buffer, length, offset,
				  (struct sockaddr *)namebuf, &bufsize);
	if (count < 0)
	    RETPUSHUNDEF;
	/* MSG_TRUNC can give oversized count; quietly lose it */
	if (count > length)
	    count = length;
#ifdef EPOC
        /* Bogus return without padding */
	bufsize = sizeof (struct sockaddr_in);
#endif
	SvCUR_set(bufsv, count);
	*SvEND(bufsv) = '\0';
	(void)SvPOK_only(bufsv);
	if (fp_utf8)
	    SvUTF8_on(bufsv);
	SvSETMAGIC(bufsv);
	/* This should not be marked tainted if the fp is marked clean */
	if (!(IoFLAGS(io) & IOf_UNTAINT))
	    SvTAINTED_on(bufsv);
	SP = ORIGMARK;
	sv_setpvn(TARG, namebuf, bufsize);
	PUSHs(TARG);
	RETURN;
    }
#else
    if (PL_op->op_type == OP_RECV)
	DIE(aTHX_ PL_no_sock_func, "recv");
#endif
    if (DO_UTF8(bufsv)) {
	/* offset adjust in characters not bytes */
	blen = sv_len_utf8(bufsv);
    }
    if (offset < 0) {
	if (-offset > (int)blen)
	    DIE(aTHX_ "Offset outside string");
	offset += blen;
    }
    if (DO_UTF8(bufsv)) {
	/* convert offset-as-chars to offset-as-bytes */
	if (offset >= (int)blen)
	    offset += SvCUR(bufsv) - blen;
	else
	    offset = utf8_hop((U8 *)buffer,offset) - (U8 *) buffer;
    }
 more_bytes:
    bufsize = SvCUR(bufsv);
    /* Allocating length + offset + 1 isn't perfect in the case of reading
       bytes from a byte file handle into a UTF8 buffer, but it won't harm us
       unduly.
       (should be 2 * length + offset + 1, or possibly something longer if
       PL_encoding is true) */
    buffer  = SvGROW(bufsv, (STRLEN)(length+offset+1));
    if (offset > 0 && (Sock_size_t)offset > bufsize) { /* Zero any newly allocated space */
    	Zero(buffer+bufsize, offset-bufsize, char);
    }
    buffer = buffer + offset;
    if (!buffer_utf8) {
	read_target = bufsv;
    } else {
	/* Best to read the bytes into a new SV, upgrade that to UTF8, then
	   concatenate it to the current buffer.  */

	/* Truncate the existing buffer to the start of where we will be
	   reading to:  */
	SvCUR_set(bufsv, offset);

	read_target = sv_newmortal();
	SvUPGRADE(read_target, SVt_PV);
	buffer = SvGROW(read_target, (STRLEN)(length + 1));
    }

    if (PL_op->op_type == OP_SYSREAD) {
#ifdef PERL_SOCK_SYSREAD_IS_RECV
	if (IoTYPE(io) == IoTYPE_SOCKET) {
	    count = PerlSock_recv(PerlIO_fileno(IoIFP(io)),
				   buffer, length, 0);
	}
	else
#endif
	{
	    count = PerlLIO_read(PerlIO_fileno(IoIFP(io)),
				  buffer, length);
	}
    }
    else
#ifdef HAS_SOCKET__bad_code_maybe
    if (IoTYPE(io) == IoTYPE_SOCKET) {
	char namebuf[MAXPATHLEN];
#if defined(VMS_DO_SOCKETS) && defined(DECCRTL_SOCKETS)
	bufsize = sizeof (struct sockaddr_in);
#else
	bufsize = sizeof namebuf;
#endif
	count = PerlSock_recvfrom(PerlIO_fileno(IoIFP(io)), buffer, length, 0,
			  (struct sockaddr *)namebuf, &bufsize);
    }
    else
#endif
    {
	count = PerlIO_read(IoIFP(io), buffer, length);
	/* PerlIO_read() - like fread() returns 0 on both error and EOF */
	if (count == 0 && PerlIO_error(IoIFP(io)))
	    count = -1;
    }
    if (count < 0) {
	if (IoTYPE(io) == IoTYPE_WRONLY)
	    report_wrongway_fh(gv, '>');
	goto say_undef;
    }
    SvCUR_set(read_target, count+(buffer - SvPVX_const(read_target)));
    *SvEND(read_target) = '\0';
    (void)SvPOK_only(read_target);
    if (fp_utf8 && !IN_BYTES) {
	/* Look at utf8 we got back and count the characters */
	const char *bend = buffer + count;
	while (buffer < bend) {
	    if (charstart) {
	        skip = UTF8SKIP(buffer);
		charskip = 0;
	    }
	    if (buffer - charskip + skip > bend) {
		/* partial character - try for rest of it */
		length = skip - (bend-buffer);
		offset = bend - SvPVX_const(bufsv);
		charstart = FALSE;
		charskip += count;
		goto more_bytes;
	    }
	    else {
		got++;
		buffer += skip;
		charstart = TRUE;
		charskip  = 0;
	    }
        }
	/* If we have not 'got' the number of _characters_ we 'wanted' get some more
	   provided amount read (count) was what was requested (length)
	 */
	if (got < wanted && count == length) {
	    length = wanted - got;
	    offset = bend - SvPVX_const(bufsv);
	    goto more_bytes;
	}
	/* return value is character count */
	count = got;
	SvUTF8_on(bufsv);
    }
    else if (buffer_utf8) {
	/* Let svcatsv upgrade the bytes we read in to utf8.
	   The buffer is a mortal so will be freed soon.  */
	sv_catsv_nomg(bufsv, read_target);
    }
    SvSETMAGIC(bufsv);
    /* This should not be marked tainted if the fp is marked clean */
    if (!(IoFLAGS(io) & IOf_UNTAINT))
	SvTAINTED_on(bufsv);
    SP = ORIGMARK;
    PUSHi(count);
    RETURN;

  say_undef:
    SP = ORIGMARK;
    RETPUSHUNDEF;
}

PP(pp_send)
{
    dVAR; dSP; dMARK; dORIGMARK; dTARGET;
    IO *io;
    SV *bufsv;
    const char *buffer;
    SSize_t retval;
    STRLEN blen;
    STRLEN orig_blen_bytes;
    const int op_type = PL_op->op_type;
    bool doing_utf8;
    U8 *tmpbuf = NULL;
    
    GV *const gv = MUTABLE_GV(*++MARK);
    if (PL_op->op_type == OP_SYSWRITE
	&& gv && (io = GvIO(gv))) {
	MAGIC * const mg = SvTIED_mg((const SV *)io, PERL_MAGIC_tiedscalar);
	if (mg) {
	    if (MARK == SP - 1) {
		SV *sv = *SP;
		mXPUSHi(sv_len(sv));
		PUTBACK;
	    }

	    return S_tied_handle_method(aTHX_ "WRITE", mark - 1, io, mg,
					G_SCALAR | ARGUMENTS_ON_STACK,
					sp - mark);
	}
    }
    if (!gv)
	goto say_undef;

    bufsv = *++MARK;

    SETERRNO(0,0);
    io = GvIO(gv);
    if (!io || !IoIFP(io) || IoTYPE(io) == IoTYPE_RDONLY) {
	retval = -1;
	if (io && IoIFP(io))
	    report_wrongway_fh(gv, '<');
	else
	    report_evil_fh(gv);
	SETERRNO(EBADF,RMS_IFI);
	goto say_undef;
    }

    /* Do this first to trigger any overloading.  */
    buffer = SvPV_const(bufsv, blen);
    orig_blen_bytes = blen;
    doing_utf8 = DO_UTF8(bufsv);

    if (PerlIO_isutf8(IoIFP(io))) {
	if (!SvUTF8(bufsv)) {
	    /* We don't modify the original scalar.  */
	    tmpbuf = bytes_to_utf8((const U8*) buffer, &blen);
	    buffer = (char *) tmpbuf;
	    doing_utf8 = TRUE;
	}
    }
    else if (doing_utf8) {
	STRLEN tmplen = blen;
	U8 * const result = bytes_from_utf8((const U8*) buffer, &tmplen, &doing_utf8);
	if (!doing_utf8) {
	    tmpbuf = result;
	    buffer = (char *) tmpbuf;
	    blen = tmplen;
	}
	else {
	    assert((char *)result == buffer);
	    Perl_croak(aTHX_ "Wide character in %s", OP_DESC(PL_op));
	}
    }

    if (op_type == OP_SYSWRITE) {
	Size_t length = 0; /* This length is in characters.  */
	STRLEN blen_chars;
	IV offset;

	if (doing_utf8) {
	    if (tmpbuf) {
		/* The SV is bytes, and we've had to upgrade it.  */
		blen_chars = orig_blen_bytes;
	    } else {
		/* The SV really is UTF-8.  */
		if (SvGMAGICAL(bufsv) || SvAMAGIC(bufsv)) {
		    /* Don't call sv_len_utf8 again because it will call magic
		       or overloading a second time, and we might get back a
		       different result.  */
		    blen_chars = utf8_length((U8*)buffer, (U8*)buffer + blen);
		} else {
		    /* It's safe, and it may well be cached.  */
		    blen_chars = sv_len_utf8(bufsv);
		}
	    }
	} else {
	    blen_chars = blen;
	}

	if (MARK >= SP) {
	    length = blen_chars;
	} else {
#if Size_t_size > IVSIZE
	    length = (Size_t)SvNVx(*++MARK);
#else
	    length = (Size_t)SvIVx(*++MARK);
#endif
	    if ((SSize_t)length < 0) {
		Safefree(tmpbuf);
		DIE(aTHX_ "Negative length");
	    }
	}

	if (MARK < SP) {
	    offset = SvIVx(*++MARK);
	    if (offset < 0) {
		if (-offset > (IV)blen_chars) {
		    Safefree(tmpbuf);
		    DIE(aTHX_ "Offset outside string");
		}
		offset += blen_chars;
	    } else if (offset > (IV)blen_chars) {
		Safefree(tmpbuf);
		DIE(aTHX_ "Offset outside string");
	    }
	} else
	    offset = 0;
	if (length > blen_chars - offset)
	    length = blen_chars - offset;
	if (doing_utf8) {
	    /* Here we convert length from characters to bytes.  */
	    if (tmpbuf || SvGMAGICAL(bufsv) || SvAMAGIC(bufsv)) {
		/* Either we had to convert the SV, or the SV is magical, or
		   the SV has overloading, in which case we can't or mustn't
		   or mustn't call it again.  */

		buffer = (const char*)utf8_hop((const U8 *)buffer, offset);
		length = utf8_hop((U8 *)buffer, length) - (U8 *)buffer;
	    } else {
		/* It's a real UTF-8 SV, and it's not going to change under
		   us.  Take advantage of any cache.  */
		I32 start = offset;
		I32 len_I32 = length;

		/* Convert the start and end character positions to bytes.
		   Remember that the second argument to sv_pos_u2b is relative
		   to the first.  */
		sv_pos_u2b(bufsv, &start, &len_I32);

		buffer += start;
		length = len_I32;
	    }
	}
	else {
	    buffer = buffer+offset;
	}
#ifdef PERL_SOCK_SYSWRITE_IS_SEND
	if (IoTYPE(io) == IoTYPE_SOCKET) {
	    retval = PerlSock_send(PerlIO_fileno(IoIFP(io)),
				   buffer, length, 0);
	}
	else
#endif
	{
	    /* See the note at doio.c:do_print about filesize limits. --jhi */
	    retval = PerlLIO_write(PerlIO_fileno(IoIFP(io)),
				   buffer, length);
	}
    }
#ifdef HAS_SOCKET
    else {
	const int flags = SvIVx(*++MARK);
	if (SP > MARK) {
	    STRLEN mlen;
	    char * const sockbuf = SvPVx(*++MARK, mlen);
	    retval = PerlSock_sendto(PerlIO_fileno(IoIFP(io)), buffer, blen,
				     flags, (struct sockaddr *)sockbuf, mlen);
	}
	else {
	    retval
		= PerlSock_send(PerlIO_fileno(IoIFP(io)), buffer, blen, flags);
	}
    }
#else
    else
	DIE(aTHX_ PL_no_sock_func, "send");
#endif

    if (retval < 0)
	goto say_undef;
    SP = ORIGMARK;
    if (doing_utf8)
        retval = utf8_length((U8*)buffer, (U8*)buffer + retval);

    Safefree(tmpbuf);
#if Size_t_size > IVSIZE
    PUSHn(retval);
#else
    PUSHi(retval);
#endif
    RETURN;

  say_undef:
    Safefree(tmpbuf);
    SP = ORIGMARK;
    RETPUSHUNDEF;
}

PP(pp_eof)
{
    dVAR; dSP;
    GV *gv;
    IO *io;
    MAGIC *mg;
    /*
     * in Perl 5.12 and later, the additional parameter is a bitmask:
     * 0 = eof
     * 1 = eof(FH)
     * 2 = eof()  <- ARGV magic
     *
     * I'll rely on the compiler's trace flow analysis to decide whether to
     * actually assign this out here, or punt it into the only block where it is
     * used. Doing it out here is DRY on the condition logic.
     */
    unsigned int which;

    if (MAXARG) {
	gv = PL_last_in_gv = MUTABLE_GV(POPs);	/* eof(FH) */
	which = 1;
    }
    else {
	EXTEND(SP, 1);

	if (PL_op->op_flags & OPf_SPECIAL) {
	    gv = PL_last_in_gv = GvEGVx(PL_argvgv);	/* eof() - ARGV magic */
	    which = 2;
	}
	else {
	    gv = PL_last_in_gv;			/* eof */
	    which = 0;
	}
    }

    if (!gv)
	RETPUSHNO;

    if ((io = GvIO(gv)) && (mg = SvTIED_mg((const SV *)io, PERL_MAGIC_tiedscalar))) {
	return tied_handle_method1("EOF", SP, io, mg, newSVuv(which));
    }

    if (!MAXARG && (PL_op->op_flags & OPf_SPECIAL)) {	/* eof() */
	if (io && !IoIFP(io)) {
	    if ((IoFLAGS(io) & IOf_START) && av_len(GvAVn(gv)) < 0) {
		IoLINES(io) = 0;
		IoFLAGS(io) &= ~IOf_START;
		do_open(gv, "-", 1, FALSE, O_RDONLY, 0, NULL);
		if (GvSV(gv))
		    sv_setpvs(GvSV(gv), "-");
		else
		    GvSV(gv) = newSVpvs("-");
		SvSETMAGIC(GvSV(gv));
	    }
	    else if (!nextargv(gv))
		RETPUSHYES;
	}
    }

    PUSHs(boolSV(do_eof(gv)));
    RETURN;
}

PP(pp_tell)
{
    dVAR; dSP; dTARGET;
    GV *gv;
    IO *io;

    if (MAXARG != 0)
	PL_last_in_gv = MUTABLE_GV(POPs);
    else
	EXTEND(SP, 1);
    gv = PL_last_in_gv;

    io = GvIO(gv);
    if (io) {
	MAGIC * const mg = SvTIED_mg((const SV *)io, PERL_MAGIC_tiedscalar);
	if (mg) {
	    return tied_handle_method("TELL", SP, io, mg);
	}
    }
    else if (!gv) {
	if (!errno)
	    SETERRNO(EBADF,RMS_IFI);
	PUSHi(-1);
	RETURN;
    }

#if LSEEKSIZE > IVSIZE
    PUSHn( do_tell(gv) );
#else
    PUSHi( do_tell(gv) );
#endif
    RETURN;
}

PP(pp_sysseek)
{
    dVAR; dSP;
    const int whence = POPi;
#if LSEEKSIZE > IVSIZE
    const Off_t offset = (Off_t)SvNVx(POPs);
#else
    const Off_t offset = (Off_t)SvIVx(POPs);
#endif

    GV * const gv = PL_last_in_gv = MUTABLE_GV(POPs);
    IO *const io = GvIO(gv);

    if (io) {
	MAGIC * const mg = SvTIED_mg((const SV *)io, PERL_MAGIC_tiedscalar);
	if (mg) {
#if LSEEKSIZE > IVSIZE
	    SV *const offset_sv = newSVnv((NV) offset);
#else
	    SV *const offset_sv = newSViv(offset);
#endif

	    return tied_handle_method2("SEEK", SP, io, mg, offset_sv,
				       newSViv(whence));
	}
    }

    if (PL_op->op_type == OP_SEEK)
	PUSHs(boolSV(do_seek(gv, offset, whence)));
    else {
	const Off_t sought = do_sysseek(gv, offset, whence);
        if (sought < 0)
            PUSHs(&PL_sv_undef);
        else {
            SV* const sv = sought ?
#if LSEEKSIZE > IVSIZE
                newSVnv((NV)sought)
#else
                newSViv(sought)
#endif
                : newSVpvn(zero_but_true, ZBTLEN);
            mPUSHs(sv);
        }
    }
    RETURN;
}

PP(pp_truncate)
{
    dVAR;
    dSP;
    /* There seems to be no consensus on the length type of truncate()
     * and ftruncate(), both off_t and size_t have supporters. In
     * general one would think that when using large files, off_t is
     * at least as wide as size_t, so using an off_t should be okay. */
    /* XXX Configure probe for the length type of *truncate() needed XXX */
    Off_t len;

#if Off_t_size > IVSIZE
    len = (Off_t)POPn;
#else
    len = (Off_t)POPi;
#endif
    /* Checking for length < 0 is problematic as the type might or
     * might not be signed: if it is not, clever compilers will moan. */
    /* XXX Configure probe for the signedness of the length type of *truncate() needed? XXX */
    SETERRNO(0,0);
    {
	int result = 1;
	GV *tmpgv;
	IO *io;

	if (PL_op->op_flags & OPf_SPECIAL) {
	    tmpgv = gv_fetchsv(POPs, 0, SVt_PVIO);

	do_ftruncate_gv:
	    io = GvIO(tmpgv);
	    if (!io)
		result = 0;
	    else {
		PerlIO *fp;
	    do_ftruncate_io:
		TAINT_PROPER("truncate");
		if (!(fp = IoIFP(io))) {
		    result = 0;
		}
		else {
		    PerlIO_flush(fp);
#ifdef HAS_TRUNCATE
		    if (ftruncate(PerlIO_fileno(fp), len) < 0)
#else
		    if (my_chsize(PerlIO_fileno(fp), len) < 0)
#endif
			result = 0;
		}
	    }
	}
	else {
	    SV * const sv = POPs;
	    const char *name;

	    if (isGV_with_GP(sv)) {
	        tmpgv = MUTABLE_GV(sv);		/* *main::FRED for example */
		goto do_ftruncate_gv;
	    }
	    else if (SvROK(sv) && isGV_with_GP(SvRV(sv))) {
	        tmpgv = MUTABLE_GV(SvRV(sv));	/* \*main::FRED for example */
		goto do_ftruncate_gv;
	    }
	    else if (SvROK(sv) && SvTYPE(SvRV(sv)) == SVt_PVIO) {
		io = MUTABLE_IO(SvRV(sv)); /* *main::FRED{IO} for example */
		goto do_ftruncate_io;
	    }

	    name = SvPV_nolen_const(sv);
	    TAINT_PROPER("truncate");
#ifdef HAS_TRUNCATE
	    if (truncate(name, len) < 0)
	        result = 0;
#else
	    {
		const int tmpfd = PerlLIO_open(name, O_RDWR);

		if (tmpfd < 0)
		    result = 0;
		else {
		    if (my_chsize(tmpfd, len) < 0)
		        result = 0;
		    PerlLIO_close(tmpfd);
		}
	    }
#endif
	}

	if (result)
	    RETPUSHYES;
	if (!errno)
	    SETERRNO(EBADF,RMS_IFI);
	RETPUSHUNDEF;
    }
}

PP(pp_ioctl)
{
    dVAR; dSP; dTARGET;
    SV * const argsv = POPs;
    const unsigned int func = POPu;
    const int optype = PL_op->op_type;
    GV * const gv = MUTABLE_GV(POPs);
    IO * const io = gv ? GvIOn(gv) : NULL;
    char *s;
    IV retval;

    if (!io || !argsv || !IoIFP(io)) {
	report_evil_fh(gv);
	SETERRNO(EBADF,RMS_IFI);	/* well, sort of... */
	RETPUSHUNDEF;
    }

    if (SvPOK(argsv) || !SvNIOK(argsv)) {
	STRLEN len;
	STRLEN need;
	s = SvPV_force(argsv, len);
	need = IOCPARM_LEN(func);
	if (len < need) {
	    s = Sv_Grow(argsv, need + 1);
	    SvCUR_set(argsv, need);
	}

	s[SvCUR(argsv)] = 17;	/* a little sanity check here */
    }
    else {
	retval = SvIV(argsv);
	s = INT2PTR(char*,retval);		/* ouch */
    }

    TAINT_PROPER(PL_op_desc[optype]);

    if (optype == OP_IOCTL)
#ifdef HAS_IOCTL
	retval = PerlLIO_ioctl(PerlIO_fileno(IoIFP(io)), func, s);
#else
	DIE(aTHX_ "ioctl is not implemented");
#endif
    else
#ifndef HAS_FCNTL
      DIE(aTHX_ "fcntl is not implemented");
#else
#if defined(OS2) && defined(__EMX__)
	retval = fcntl(PerlIO_fileno(IoIFP(io)), func, (int)s);
#else
	retval = fcntl(PerlIO_fileno(IoIFP(io)), func, s);
#endif
#endif

#if defined(HAS_IOCTL) || defined(HAS_FCNTL)
    if (SvPOK(argsv)) {
	if (s[SvCUR(argsv)] != 17)
	    DIE(aTHX_ "Possible memory corruption: %s overflowed 3rd argument",
		OP_NAME(PL_op));
	s[SvCUR(argsv)] = 0;		/* put our null back */
	SvSETMAGIC(argsv);		/* Assume it has changed */
    }

    if (retval == -1)
	RETPUSHUNDEF;
    if (retval != 0) {
	PUSHi(retval);
    }
    else {
	PUSHp(zero_but_true, ZBTLEN);
    }
#endif
    RETURN;
}

PP(pp_flock)
{
#ifdef FLOCK
    dVAR; dSP; dTARGET;
    I32 value;
    const int argtype = POPi;
    GV * const gv = (MAXARG == 0) ? PL_last_in_gv : MUTABLE_GV(POPs);
    IO *const io = GvIO(gv);
    PerlIO *const fp = io ? IoIFP(io) : NULL;

    /* XXX Looks to me like io is always NULL at this point */
    if (fp) {
	(void)PerlIO_flush(fp);
	value = (I32)(PerlLIO_flock(PerlIO_fileno(fp), argtype) >= 0);
    }
    else {
	report_evil_fh(gv);
	value = 0;
	SETERRNO(EBADF,RMS_IFI);
    }
    PUSHi(value);
    RETURN;
#else
    DIE(aTHX_ PL_no_func, "flock()");
#endif
}

/* Sockets. */

PP(pp_socket)
{
#ifdef HAS_SOCKET
    dVAR; dSP;
    const int protocol = POPi;
    const int type = POPi;
    const int domain = POPi;
    GV * const gv = MUTABLE_GV(POPs);
    register IO * const io = gv ? GvIOn(gv) : NULL;
    int fd;

    if (!io) {
	report_evil_fh(gv);
	if (io && IoIFP(io))
	    do_close(gv, FALSE);
	SETERRNO(EBADF,LIB_INVARG);
	RETPUSHUNDEF;
    }

    if (IoIFP(io))
	do_close(gv, FALSE);

    TAINT_PROPER("socket");
    fd = PerlSock_socket(domain, type, protocol);
    if (fd < 0)
	RETPUSHUNDEF;
    IoIFP(io) = PerlIO_fdopen(fd, "r"SOCKET_OPEN_MODE);	/* stdio gets confused about sockets */
    IoOFP(io) = PerlIO_fdopen(fd, "w"SOCKET_OPEN_MODE);
    IoTYPE(io) = IoTYPE_SOCKET;
    if (!IoIFP(io) || !IoOFP(io)) {
	if (IoIFP(io)) PerlIO_close(IoIFP(io));
	if (IoOFP(io)) PerlIO_close(IoOFP(io));
	if (!IoIFP(io) && !IoOFP(io)) PerlLIO_close(fd);
	RETPUSHUNDEF;
    }
#if defined(HAS_FCNTL) && defined(F_SETFD)
    fcntl(fd, F_SETFD, fd > PL_maxsysfd);	/* ensure close-on-exec */
#endif

#ifdef EPOC
    setbuf( IoIFP(io), NULL); /* EPOC gets confused about sockets */
#endif

    RETPUSHYES;
#else
    DIE(aTHX_ PL_no_sock_func, "socket");
#endif
}

PP(pp_sockpair)
{
#if defined (HAS_SOCKETPAIR) || (defined (HAS_SOCKET) && defined(SOCK_DGRAM) && defined(AF_INET) && defined(PF_INET))
    dVAR; dSP;
    const int protocol = POPi;
    const int type = POPi;
    const int domain = POPi;
    GV * const gv2 = MUTABLE_GV(POPs);
    GV * const gv1 = MUTABLE_GV(POPs);
    register IO * const io1 = gv1 ? GvIOn(gv1) : NULL;
    register IO * const io2 = gv2 ? GvIOn(gv2) : NULL;
    int fd[2];

    if (!io1)
	report_evil_fh(gv1);
    if (!io2)
	report_evil_fh(gv2);

    if (io1 && IoIFP(io1))
	do_close(gv1, FALSE);
    if (io2 && IoIFP(io2))
	do_close(gv2, FALSE);

    if (!io1 || !io2)
	RETPUSHUNDEF;

    TAINT_PROPER("socketpair");
    if (PerlSock_socketpair(domain, type, protocol, fd) < 0)
	RETPUSHUNDEF;
    IoIFP(io1) = PerlIO_fdopen(fd[0], "r"SOCKET_OPEN_MODE);
    IoOFP(io1) = PerlIO_fdopen(fd[0], "w"SOCKET_OPEN_MODE);
    IoTYPE(io1) = IoTYPE_SOCKET;
    IoIFP(io2) = PerlIO_fdopen(fd[1], "r"SOCKET_OPEN_MODE);
    IoOFP(io2) = PerlIO_fdopen(fd[1], "w"SOCKET_OPEN_MODE);
    IoTYPE(io2) = IoTYPE_SOCKET;
    if (!IoIFP(io1) || !IoOFP(io1) || !IoIFP(io2) || !IoOFP(io2)) {
	if (IoIFP(io1)) PerlIO_close(IoIFP(io1));
	if (IoOFP(io1)) PerlIO_close(IoOFP(io1));
	if (!IoIFP(io1) && !IoOFP(io1)) PerlLIO_close(fd[0]);
	if (IoIFP(io2)) PerlIO_close(IoIFP(io2));
	if (IoOFP(io2)) PerlIO_close(IoOFP(io2));
	if (!IoIFP(io2) && !IoOFP(io2)) PerlLIO_close(fd[1]);
	RETPUSHUNDEF;
    }
#if defined(HAS_FCNTL) && defined(F_SETFD)
    fcntl(fd[0],F_SETFD,fd[0] > PL_maxsysfd);	/* ensure close-on-exec */
    fcntl(fd[1],F_SETFD,fd[1] > PL_maxsysfd);	/* ensure close-on-exec */
#endif

    RETPUSHYES;
#else
    DIE(aTHX_ PL_no_sock_func, "socketpair");
#endif
}

PP(pp_bind)
{
#ifdef HAS_SOCKET
    dVAR; dSP;
    SV * const addrsv = POPs;
    /* OK, so on what platform does bind modify addr?  */
    const char *addr;
    GV * const gv = MUTABLE_GV(POPs);
    register IO * const io = GvIOn(gv);
    STRLEN len;
    const int op_type = PL_op->op_type;

    if (!io || !IoIFP(io))
	goto nuts;

    addr = SvPV_const(addrsv, len);
    TAINT_PROPER(PL_op_desc[op_type]);
    if ((op_type == OP_BIND
	 ? PerlSock_bind(PerlIO_fileno(IoIFP(io)), (struct sockaddr *)addr, len)
	 : PerlSock_connect(PerlIO_fileno(IoIFP(io)), (struct sockaddr *)addr, len))
	>= 0)
	RETPUSHYES;
    else
	RETPUSHUNDEF;

nuts:
    report_evil_fh(gv);
    SETERRNO(EBADF,SS_IVCHAN);
    RETPUSHUNDEF;
#else
    DIE(aTHX_ PL_no_sock_func, PL_op_desc[PL_op->op_type]);
#endif
}

PP(pp_listen)
{
#ifdef HAS_SOCKET
    dVAR; dSP;
    const int backlog = POPi;
    GV * const gv = MUTABLE_GV(POPs);
    register IO * const io = gv ? GvIOn(gv) : NULL;

    if (!io || !IoIFP(io))
	goto nuts;

    if (PerlSock_listen(PerlIO_fileno(IoIFP(io)), backlog) >= 0)
	RETPUSHYES;
    else
	RETPUSHUNDEF;

nuts:
    report_evil_fh(gv);
    SETERRNO(EBADF,SS_IVCHAN);
    RETPUSHUNDEF;
#else
    DIE(aTHX_ PL_no_sock_func, "listen");
#endif
}

PP(pp_accept)
{
#ifdef HAS_SOCKET
    dVAR; dSP; dTARGET;
    register IO *nstio;
    register IO *gstio;
    char namebuf[MAXPATHLEN];
#if (defined(VMS_DO_SOCKETS) && defined(DECCRTL_SOCKETS)) || defined(MPE) || defined(__QNXNTO__)
    Sock_size_t len = sizeof (struct sockaddr_in);
#else
    Sock_size_t len = sizeof namebuf;
#endif
    GV * const ggv = MUTABLE_GV(POPs);
    GV * const ngv = MUTABLE_GV(POPs);
    int fd;

    if (!ngv)
	goto badexit;
    if (!ggv)
	goto nuts;

    gstio = GvIO(ggv);
    if (!gstio || !IoIFP(gstio))
	goto nuts;

    nstio = GvIOn(ngv);
    fd = PerlSock_accept(PerlIO_fileno(IoIFP(gstio)), (struct sockaddr *) namebuf, &len);
#if defined(OEMVS)
    if (len == 0) {
	/* Some platforms indicate zero length when an AF_UNIX client is
	 * not bound. Simulate a non-zero-length sockaddr structure in
	 * this case. */
	namebuf[0] = 0;        /* sun_len */
	namebuf[1] = AF_UNIX;  /* sun_family */
	len = 2;
    }
#endif

    if (fd < 0)
	goto badexit;
    if (IoIFP(nstio))
	do_close(ngv, FALSE);
    IoIFP(nstio) = PerlIO_fdopen(fd, "r"SOCKET_OPEN_MODE);
    IoOFP(nstio) = PerlIO_fdopen(fd, "w"SOCKET_OPEN_MODE);
    IoTYPE(nstio) = IoTYPE_SOCKET;
    if (!IoIFP(nstio) || !IoOFP(nstio)) {
	if (IoIFP(nstio)) PerlIO_close(IoIFP(nstio));
	if (IoOFP(nstio)) PerlIO_close(IoOFP(nstio));
	if (!IoIFP(nstio) && !IoOFP(nstio)) PerlLIO_close(fd);
	goto badexit;
    }
#if defined(HAS_FCNTL) && defined(F_SETFD)
    fcntl(fd, F_SETFD, fd > PL_maxsysfd);	/* ensure close-on-exec */
#endif

#ifdef EPOC
    len = sizeof (struct sockaddr_in); /* EPOC somehow truncates info */
    setbuf( IoIFP(nstio), NULL); /* EPOC gets confused about sockets */
#endif
#ifdef __SCO_VERSION__
    len = sizeof (struct sockaddr_in); /* OpenUNIX 8 somehow truncates info */
#endif

    PUSHp(namebuf, len);
    RETURN;

nuts:
    report_evil_fh(ggv);
    SETERRNO(EBADF,SS_IVCHAN);

badexit:
    RETPUSHUNDEF;

#else
    DIE(aTHX_ PL_no_sock_func, "accept");
#endif
}

PP(pp_shutdown)
{
#ifdef HAS_SOCKET
    dVAR; dSP; dTARGET;
    const int how = POPi;
    GV * const gv = MUTABLE_GV(POPs);
    register IO * const io = GvIOn(gv);

    if (!io || !IoIFP(io))
	goto nuts;

    PUSHi( PerlSock_shutdown(PerlIO_fileno(IoIFP(io)), how) >= 0 );
    RETURN;

nuts:
    report_evil_fh(gv);
    SETERRNO(EBADF,SS_IVCHAN);
    RETPUSHUNDEF;
#else
    DIE(aTHX_ PL_no_sock_func, "shutdown");
#endif
}

PP(pp_ssockopt)
{
#ifdef HAS_SOCKET
    dVAR; dSP;
    const int optype = PL_op->op_type;
    SV * const sv = (optype == OP_GSOCKOPT) ? sv_2mortal(newSV(257)) : POPs;
    const unsigned int optname = (unsigned int) POPi;
    const unsigned int lvl = (unsigned int) POPi;
    GV * const gv = MUTABLE_GV(POPs);
    register IO * const io = GvIOn(gv);
    int fd;
    Sock_size_t len;

    if (!io || !IoIFP(io))
	goto nuts;

    fd = PerlIO_fileno(IoIFP(io));
    switch (optype) {
    case OP_GSOCKOPT:
	SvGROW(sv, 257);
	(void)SvPOK_only(sv);
	SvCUR_set(sv,256);
	*SvEND(sv) ='\0';
	len = SvCUR(sv);
	if (PerlSock_getsockopt(fd, lvl, optname, SvPVX(sv), &len) < 0)
	    goto nuts2;
	SvCUR_set(sv, len);
	*SvEND(sv) ='\0';
	PUSHs(sv);
	break;
    case OP_SSOCKOPT: {
#if defined(__SYMBIAN32__)
# define SETSOCKOPT_OPTION_VALUE_T void *
#else
# define SETSOCKOPT_OPTION_VALUE_T const char *
#endif
	/* XXX TODO: We need to have a proper type (a Configure probe,
	 * etc.) for what the C headers think of the third argument of
	 * setsockopt(), the option_value read-only buffer: is it
	 * a "char *", or a "void *", const or not.  Some compilers
	 * don't take kindly to e.g. assuming that "char *" implicitly
	 * promotes to a "void *", or to explicitly promoting/demoting
	 * consts to non/vice versa.  The "const void *" is the SUS
	 * definition, but that does not fly everywhere for the above
	 * reasons. */
	    SETSOCKOPT_OPTION_VALUE_T buf;
	    int aint;
	    if (SvPOKp(sv)) {
		STRLEN l;
		buf = (SETSOCKOPT_OPTION_VALUE_T) SvPV_const(sv, l);
		len = l;
	    }
	    else {
		aint = (int)SvIV(sv);
		buf = (SETSOCKOPT_OPTION_VALUE_T) &aint;
		len = sizeof(int);
	    }
	    if (PerlSock_setsockopt(fd, lvl, optname, buf, len) < 0)
		goto nuts2;
	    PUSHs(&PL_sv_yes);
	}
	break;
    }
    RETURN;

nuts:
    report_evil_fh(gv);
    SETERRNO(EBADF,SS_IVCHAN);
nuts2:
    RETPUSHUNDEF;

#else
    DIE(aTHX_ PL_no_sock_func, PL_op_desc[PL_op->op_type]);
#endif
}

PP(pp_getpeername)
{
#ifdef HAS_SOCKET
    dVAR; dSP;
    const int optype = PL_op->op_type;
    GV * const gv = MUTABLE_GV(POPs);
    register IO * const io = GvIOn(gv);
    Sock_size_t len;
    SV *sv;
    int fd;

    if (!io || !IoIFP(io))
	goto nuts;

    sv = sv_2mortal(newSV(257));
    (void)SvPOK_only(sv);
    len = 256;
    SvCUR_set(sv, len);
    *SvEND(sv) ='\0';
    fd = PerlIO_fileno(IoIFP(io));
    switch (optype) {
    case OP_GETSOCKNAME:
	if (PerlSock_getsockname(fd, (struct sockaddr *)SvPVX(sv), &len) < 0)
	    goto nuts2;
	break;
    case OP_GETPEERNAME:
	if (PerlSock_getpeername(fd, (struct sockaddr *)SvPVX(sv), &len) < 0)
	    goto nuts2;
#if defined(VMS_DO_SOCKETS) && defined (DECCRTL_SOCKETS)
	{
	    static const char nowhere[] = "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0";
	    /* If the call succeeded, make sure we don't have a zeroed port/addr */
	    if (((struct sockaddr *)SvPVX_const(sv))->sa_family == AF_INET &&
		!memcmp(SvPVX_const(sv) + sizeof(u_short), nowhere,
			sizeof(u_short) + sizeof(struct in_addr))) {
		goto nuts2;	
	    }
	}
#endif
	break;
    }
#ifdef BOGUS_GETNAME_RETURN
    /* Interactive Unix, getpeername() and getsockname()
      does not return valid namelen */
    if (len == BOGUS_GETNAME_RETURN)
	len = sizeof(struct sockaddr);
#endif
    SvCUR_set(sv, len);
    *SvEND(sv) ='\0';
    PUSHs(sv);
    RETURN;

nuts:
    report_evil_fh(gv);
    SETERRNO(EBADF,SS_IVCHAN);
nuts2:
    RETPUSHUNDEF;

#else
    DIE(aTHX_ PL_no_sock_func, PL_op_desc[PL_op->op_type]);
#endif
}

/* Stat calls. */

PP(pp_stat)
{
    dVAR;
    dSP;
    GV *gv = NULL;
    IO *io;
    I32 gimme;
    I32 max = 13;

    if (PL_op->op_flags & OPf_REF) {
	gv = cGVOP_gv;
	if (PL_op->op_type == OP_LSTAT) {
	    if (gv != PL_defgv) {
	    do_fstat_warning_check:
		Perl_ck_warner(aTHX_ packWARN(WARN_IO),
			       "lstat() on filehandle %s", gv ? GvENAME(gv) : "");
	    } else if (PL_laststype != OP_LSTAT)
		Perl_croak(aTHX_ "The stat preceding lstat() wasn't an lstat");
	}

      do_fstat:
	if (gv != PL_defgv) {
	    PL_laststype = OP_STAT;
	    PL_statgv = gv;
	    sv_setpvs(PL_statname, "");
            if(gv) {
                io = GvIO(gv);
                do_fstat_have_io:
                if (io) {
                    if (IoIFP(io)) {
                        PL_laststatval = 
                            PerlLIO_fstat(PerlIO_fileno(IoIFP(io)), &PL_statcache);   
                    } else if (IoDIRP(io)) {
                        PL_laststatval =
                            PerlLIO_fstat(my_dirfd(IoDIRP(io)), &PL_statcache);
                    } else {
                        PL_laststatval = -1;
                    }
	        }
            }
        }

	if (PL_laststatval < 0) {
	    report_evil_fh(gv);
	    max = 0;
	}
    }
    else {
	SV* const sv = POPs;
	if (isGV_with_GP(sv)) {
	    gv = MUTABLE_GV(sv);
	    goto do_fstat;
	} else if(SvROK(sv) && isGV_with_GP(SvRV(sv))) {
            gv = MUTABLE_GV(SvRV(sv));
            if (PL_op->op_type == OP_LSTAT)
                goto do_fstat_warning_check;
            goto do_fstat;
        } else if (SvROK(sv) && SvTYPE(SvRV(sv)) == SVt_PVIO) { 
            io = MUTABLE_IO(SvRV(sv));
            if (PL_op->op_type == OP_LSTAT)
                goto do_fstat_warning_check;
            goto do_fstat_have_io; 
        }
        
	sv_setpv(PL_statname, SvPV_nolen_const(sv));
	PL_statgv = NULL;
	PL_laststype = PL_op->op_type;
	if (PL_op->op_type == OP_LSTAT)
	    PL_laststatval = PerlLIO_lstat(SvPV_nolen_const(PL_statname), &PL_statcache);
	else
	    PL_laststatval = PerlLIO_stat(SvPV_nolen_const(PL_statname), &PL_statcache);
	if (PL_laststatval < 0) {
	    if (ckWARN(WARN_NEWLINE) && strchr(SvPV_nolen_const(PL_statname), '\n'))
		Perl_warner(aTHX_ packWARN(WARN_NEWLINE), PL_warn_nl, "stat");
	    max = 0;
	}
    }

    gimme = GIMME_V;
    if (gimme != G_ARRAY) {
	if (gimme != G_VOID)
	    XPUSHs(boolSV(max));
	RETURN;
    }
    if (max) {
	EXTEND(SP, max);
	EXTEND_MORTAL(max);
	mPUSHi(PL_statcache.st_dev);
	mPUSHi(PL_statcache.st_ino);
	mPUSHu(PL_statcache.st_mode);
	mPUSHu(PL_statcache.st_nlink);
#if Uid_t_size > IVSIZE
	mPUSHn(PL_statcache.st_uid);
#else
#   if Uid_t_sign <= 0
	mPUSHi(PL_statcache.st_uid);
#   else
	mPUSHu(PL_statcache.st_uid);
#   endif
#endif
#if Gid_t_size > IVSIZE
	mPUSHn(PL_statcache.st_gid);
#else
#   if Gid_t_sign <= 0
	mPUSHi(PL_statcache.st_gid);
#   else
	mPUSHu(PL_statcache.st_gid);
#   endif
#endif
#ifdef USE_STAT_RDEV
	mPUSHi(PL_statcache.st_rdev);
#else
	PUSHs(newSVpvs_flags("", SVs_TEMP));
#endif
#if Off_t_size > IVSIZE
	mPUSHn(PL_statcache.st_size);
#else
	mPUSHi(PL_statcache.st_size);
#endif
#ifdef BIG_TIME
	mPUSHn(PL_statcache.st_atime);
	mPUSHn(PL_statcache.st_mtime);
	mPUSHn(PL_statcache.st_ctime);
#else
	mPUSHi(PL_statcache.st_atime);
	mPUSHi(PL_statcache.st_mtime);
	mPUSHi(PL_statcache.st_ctime);
#endif
#ifdef USE_STAT_BLOCKS
	mPUSHu(PL_statcache.st_blksize);
	mPUSHu(PL_statcache.st_blocks);
#else
	PUSHs(newSVpvs_flags("", SVs_TEMP));
	PUSHs(newSVpvs_flags("", SVs_TEMP));
#endif
    }
    RETURN;
}

#define tryAMAGICftest_MG(chr) STMT_START { \
	if ( (SvFLAGS(TOPs) & (SVf_ROK|SVs_GMG)) \
		&& S_try_amagic_ftest(aTHX_ chr)) \
	    return NORMAL; \
    } STMT_END

STATIC bool
S_try_amagic_ftest(pTHX_ char chr) {
    dVAR;
    dSP;
    SV* const arg = TOPs;

    assert(chr != '?');
    SvGETMAGIC(arg);

    if ((PL_op->op_flags & OPf_KIDS)
	    && SvAMAGIC(TOPs))
    {
	const char tmpchr = chr;
	const OP *next;
	SV * const tmpsv = amagic_call(arg,
				newSVpvn_flags(&tmpchr, 1, SVs_TEMP),
				ftest_amg, AMGf_unary);

	if (!tmpsv)
	    return FALSE;

	SPAGAIN;

	next = PL_op->op_next;
	if (next->op_type >= OP_FTRREAD &&
	    next->op_type <= OP_FTBINARY &&
	    next->op_private & OPpFT_STACKED
	) {
	    if (SvTRUE(tmpsv))
		/* leave the object alone */
		return TRUE;
	}

	SETs(tmpsv);
	PUTBACK;
	return TRUE;
    }
    return FALSE;
}


/* This macro is used by the stacked filetest operators :
 * if the previous filetest failed, short-circuit and pass its value.
 * Else, discard it from the stack and continue. --rgs
 */
#define STACKED_FTEST_CHECK if (PL_op->op_private & OPpFT_STACKED) { \
	if (!SvTRUE(TOPs)) { RETURN; } \
	else { (void)POPs; PUTBACK; } \
    }

PP(pp_ftrread)
{
    dVAR;
    I32 result;
    /* Not const, because things tweak this below. Not bool, because there's
       no guarantee that OPp_FT_ACCESS is <= CHAR_MAX  */
#if defined(HAS_ACCESS) || defined (PERL_EFF_ACCESS)
    I32 use_access = PL_op->op_private & OPpFT_ACCESS;
    /* Giving some sort of initial value silences compilers.  */
#  ifdef R_OK
    int access_mode = R_OK;
#  else
    int access_mode = 0;
#  endif
#else
    /* access_mode is never used, but leaving use_access in makes the
       conditional compiling below much clearer.  */
    I32 use_access = 0;
#endif
    Mode_t stat_mode = S_IRUSR;

    bool effective = FALSE;
    char opchar = '?';
    dSP;

    switch (PL_op->op_type) {
    case OP_FTRREAD:	opchar = 'R'; break;
    case OP_FTRWRITE:	opchar = 'W'; break;
    case OP_FTREXEC:	opchar = 'X'; break;
    case OP_FTEREAD:	opchar = 'r'; break;
    case OP_FTEWRITE:	opchar = 'w'; break;
    case OP_FTEEXEC:	opchar = 'x'; break;
    }
    tryAMAGICftest_MG(opchar);

    STACKED_FTEST_CHECK;

    switch (PL_op->op_type) {
    case OP_FTRREAD:
#if !(defined(HAS_ACCESS) && defined(R_OK))
	use_access = 0;
#endif
	break;

    case OP_FTRWRITE:
#if defined(HAS_ACCESS) && defined(W_OK)
	access_mode = W_OK;
#else
	use_access = 0;
#endif
	stat_mode = S_IWUSR;
	break;

    case OP_FTREXEC:
#if defined(HAS_ACCESS) && defined(X_OK)
	access_mode = X_OK;
#else
	use_access = 0;
#endif
	stat_mode = S_IXUSR;
	break;

    case OP_FTEWRITE:
#ifdef PERL_EFF_ACCESS
	access_mode = W_OK;
#endif
	stat_mode = S_IWUSR;
	/* fall through */

    case OP_FTEREAD:
#ifndef PERL_EFF_ACCESS
	use_access = 0;
#endif
	effective = TRUE;
	break;

    case OP_FTEEXEC:
#ifdef PERL_EFF_ACCESS
	access_mode = X_OK;
#else
	use_access = 0;
#endif
	stat_mode = S_IXUSR;
	effective = TRUE;
	break;
    }

    if (use_access) {
#if defined(HAS_ACCESS) || defined (PERL_EFF_ACCESS)
	const char *name = POPpx;
	if (effective) {
#  ifdef PERL_EFF_ACCESS
	    result = PERL_EFF_ACCESS(name, access_mode);
#  else
	    DIE(aTHX_ "panic: attempt to call PERL_EFF_ACCESS in %s",
		OP_NAME(PL_op));
#  endif
	}
	else {
#  ifdef HAS_ACCESS
	    result = access(name, access_mode);
#  else
	    DIE(aTHX_ "panic: attempt to call access() in %s", OP_NAME(PL_op));
#  endif
	}
	if (result == 0)
	    RETPUSHYES;
	if (result < 0)
	    RETPUSHUNDEF;
	RETPUSHNO;
#endif
    }

    result = my_stat_flags(0);
    SPAGAIN;
    if (result < 0)
	RETPUSHUNDEF;
    if (cando(stat_mode, effective, &PL_statcache))
	RETPUSHYES;
    RETPUSHNO;
}

PP(pp_ftis)
{
    dVAR;
    I32 result;
    const int op_type = PL_op->op_type;
    char opchar = '?';
    dSP;

    switch (op_type) {
    case OP_FTIS:	opchar = 'e'; break;
    case OP_FTSIZE:	opchar = 's'; break;
    case OP_FTMTIME:	opchar = 'M'; break;
    case OP_FTCTIME:	opchar = 'C'; break;
    case OP_FTATIME:	opchar = 'A'; break;
    }
    tryAMAGICftest_MG(opchar);

    STACKED_FTEST_CHECK;

    result = my_stat_flags(0);
    SPAGAIN;
    if (result < 0)
	RETPUSHUNDEF;
    if (op_type == OP_FTIS)
	RETPUSHYES;
    {
	/* You can't dTARGET inside OP_FTIS, because you'll get
	   "panic: pad_sv po" - the op is not flagged to have a target.  */
	dTARGET;
	switch (op_type) {
	case OP_FTSIZE:
#if Off_t_size > IVSIZE
	    PUSHn(PL_statcache.st_size);
#else
	    PUSHi(PL_statcache.st_size);
#endif
	    break;
	case OP_FTMTIME:
	    PUSHn( (((NV)PL_basetime - PL_statcache.st_mtime)) / 86400.0 );
	    break;
	case OP_FTATIME:
	    PUSHn( (((NV)PL_basetime - PL_statcache.st_atime)) / 86400.0 );
	    break;
	case OP_FTCTIME:
	    PUSHn( (((NV)PL_basetime - PL_statcache.st_ctime)) / 86400.0 );
	    break;
	}
    }
    RETURN;
}

PP(pp_ftrowned)
{
    dVAR;
    I32 result;
    char opchar = '?';
    dSP;

    switch (PL_op->op_type) {
    case OP_FTROWNED:	opchar = 'O'; break;
    case OP_FTEOWNED:	opchar = 'o'; break;
    case OP_FTZERO:	opchar = 'z'; break;
    case OP_FTSOCK:	opchar = 'S'; break;
    case OP_FTCHR:	opchar = 'c'; break;
    case OP_FTBLK:	opchar = 'b'; break;
    case OP_FTFILE:	opchar = 'f'; break;
    case OP_FTDIR:	opchar = 'd'; break;
    case OP_FTPIPE:	opchar = 'p'; break;
    case OP_FTSUID:	opchar = 'u'; break;
    case OP_FTSGID:	opchar = 'g'; break;
    case OP_FTSVTX:	opchar = 'k'; break;
    }
    tryAMAGICftest_MG(opchar);

    STACKED_FTEST_CHECK;

    /* I believe that all these three are likely to be defined on most every
       system these days.  */
#ifndef S_ISUID
    if(PL_op->op_type == OP_FTSUID) {
	if ((PL_op->op_flags & OPf_REF) == 0 && (PL_op->op_private & OPpFT_STACKED) == 0)
	    (void) POPs;
	RETPUSHNO;
    }
#endif
#ifndef S_ISGID
    if(PL_op->op_type == OP_FTSGID) {
	if ((PL_op->op_flags & OPf_REF) == 0 && (PL_op->op_private & OPpFT_STACKED) == 0)
	    (void) POPs;
	RETPUSHNO;
    }
#endif
#ifndef S_ISVTX
    if(PL_op->op_type == OP_FTSVTX) {
	if ((PL_op->op_flags & OPf_REF) == 0 && (PL_op->op_private & OPpFT_STACKED) == 0)
	    (void) POPs;
	RETPUSHNO;
    }
#endif

    result = my_stat_flags(0);
    SPAGAIN;
    if (result < 0)
	RETPUSHUNDEF;
    switch (PL_op->op_type) {
    case OP_FTROWNED:
	if (PL_statcache.st_uid == PL_uid)
	    RETPUSHYES;
	break;
    case OP_FTEOWNED:
	if (PL_statcache.st_uid == PL_euid)
	    RETPUSHYES;
	break;
    case OP_FTZERO:
	if (PL_statcache.st_size == 0)
	    RETPUSHYES;
	break;
    case OP_FTSOCK:
	if (S_ISSOCK(PL_statcache.st_mode))
	    RETPUSHYES;
	break;
    case OP_FTCHR:
	if (S_ISCHR(PL_statcache.st_mode))
	    RETPUSHYES;
	break;
    case OP_FTBLK:
	if (S_ISBLK(PL_statcache.st_mode))
	    RETPUSHYES;
	break;
    case OP_FTFILE:
	if (S_ISREG(PL_statcache.st_mode))
	    RETPUSHYES;
	break;
    case OP_FTDIR:
	if (S_ISDIR(PL_statcache.st_mode))
	    RETPUSHYES;
	break;
    case OP_FTPIPE:
	if (S_ISFIFO(PL_statcache.st_mode))
	    RETPUSHYES;
	break;
#ifdef S_ISUID
    case OP_FTSUID:
	if (PL_statcache.st_mode & S_ISUID)
	    RETPUSHYES;
	break;
#endif
#ifdef S_ISGID
    case OP_FTSGID:
	if (PL_statcache.st_mode & S_ISGID)
	    RETPUSHYES;
	break;
#endif
#ifdef S_ISVTX
    case OP_FTSVTX:
	if (PL_statcache.st_mode & S_ISVTX)
	    RETPUSHYES;
	break;
#endif
    }
    RETPUSHNO;
}

PP(pp_ftlink)
{
    dVAR;
    dSP;
    I32 result;

    tryAMAGICftest_MG('l');
    result = my_lstat_flags(0);
    SPAGAIN;

    if (result < 0)
	RETPUSHUNDEF;
    if (S_ISLNK(PL_statcache.st_mode))
	RETPUSHYES;
    RETPUSHNO;
}

PP(pp_fttty)
{
    dVAR;
    dSP;
    int fd;
    GV *gv;
    SV *tmpsv = NULL;
    char *name = NULL;
    STRLEN namelen;

    tryAMAGICftest_MG('t');

    STACKED_FTEST_CHECK;

    if (PL_op->op_flags & OPf_REF)
	gv = cGVOP_gv;
    else if (isGV_with_GP(TOPs))
	gv = MUTABLE_GV(POPs);
    else if (SvROK(TOPs) && isGV(SvRV(TOPs)))
	gv = MUTABLE_GV(SvRV(POPs));
    else {
	tmpsv = POPs;
	name = SvPV_nomg(tmpsv, namelen);
	gv = gv_fetchpvn_flags(name, namelen, SvUTF8(tmpsv), SVt_PVIO);
    }

    if (GvIO(gv) && IoIFP(GvIOp(gv)))
	fd = PerlIO_fileno(IoIFP(GvIOp(gv)));
    else if (tmpsv && SvOK(tmpsv)) {
	if (isDIGIT(*name))
	    fd = atoi(name);
	else 
	    RETPUSHUNDEF;
    }
    else
	RETPUSHUNDEF;
    if (PerlLIO_isatty(fd))
	RETPUSHYES;
    RETPUSHNO;
}

#if defined(atarist) /* this will work with atariST. Configure will
			make guesses for other systems. */
# define FILE_base(f) ((f)->_base)
# define FILE_ptr(f) ((f)->_ptr)
# define FILE_cnt(f) ((f)->_cnt)
# define FILE_bufsiz(f) ((f)->_cnt + ((f)->_ptr - (f)->_base))
#endif

PP(pp_fttext)
{
    dVAR;
    dSP;
    I32 i;
    I32 len;
    I32 odd = 0;
    STDCHAR tbuf[512];
    register STDCHAR *s;
    register IO *io;
    register SV *sv;
    GV *gv;
    PerlIO *fp;

    tryAMAGICftest_MG(PL_op->op_type == OP_FTTEXT ? 'T' : 'B');

    STACKED_FTEST_CHECK;

    if (PL_op->op_flags & OPf_REF)
	gv = cGVOP_gv;
    else if (isGV_with_GP(TOPs))
	gv = MUTABLE_GV(POPs);
    else if (SvROK(TOPs) && isGV(SvRV(TOPs)))
	gv = MUTABLE_GV(SvRV(POPs));
    else
	gv = NULL;

    if (gv) {
	EXTEND(SP, 1);
	if (gv == PL_defgv) {
	    if (PL_statgv)
		io = GvIO(PL_statgv);
	    else {
		sv = PL_statname;
		goto really_filename;
	    }
	}
	else {
	    PL_statgv = gv;
	    PL_laststatval = -1;
	    sv_setpvs(PL_statname, "");
	    io = GvIO(PL_statgv);
	}
	if (io && IoIFP(io)) {
	    if (! PerlIO_has_base(IoIFP(io)))
		DIE(aTHX_ "-T and -B not implemented on filehandles");
	    PL_laststatval = PerlLIO_fstat(PerlIO_fileno(IoIFP(io)), &PL_statcache);
	    if (PL_laststatval < 0)
		RETPUSHUNDEF;
	    if (S_ISDIR(PL_statcache.st_mode)) { /* handle NFS glitch */
		if (PL_op->op_type == OP_FTTEXT)
		    RETPUSHNO;
		else
		    RETPUSHYES;
            }
	    if (PerlIO_get_cnt(IoIFP(io)) <= 0) {
		i = PerlIO_getc(IoIFP(io));
		if (i != EOF)
		    (void)PerlIO_ungetc(IoIFP(io),i);
	    }
	    if (PerlIO_get_cnt(IoIFP(io)) <= 0)	/* null file is anything */
		RETPUSHYES;
	    len = PerlIO_get_bufsiz(IoIFP(io));
	    s = (STDCHAR *) PerlIO_get_base(IoIFP(io));
	    /* sfio can have large buffers - limit to 512 */
	    if (len > 512)
		len = 512;
	}
	else {
	    report_evil_fh(cGVOP_gv);
	    SETERRNO(EBADF,RMS_IFI);
	    RETPUSHUNDEF;
	}
    }
    else {
	sv = POPs;
      really_filename:
	PL_statgv = NULL;
	PL_laststype = OP_STAT;
	sv_setpv(PL_statname, SvPV_nomg_const_nolen(sv));
	if (!(fp = PerlIO_open(SvPVX_const(PL_statname), "r"))) {
	    if (ckWARN(WARN_NEWLINE) && strchr(SvPV_nolen_const(PL_statname),
					       '\n'))
		Perl_warner(aTHX_ packWARN(WARN_NEWLINE), PL_warn_nl, "open");
	    RETPUSHUNDEF;
	}
	PL_laststatval = PerlLIO_fstat(PerlIO_fileno(fp), &PL_statcache);
	if (PL_laststatval < 0)	{
	    (void)PerlIO_close(fp);
	    RETPUSHUNDEF;
	}
	PerlIO_binmode(aTHX_ fp, '<', O_BINARY, NULL);
	len = PerlIO_read(fp, tbuf, sizeof(tbuf));
	(void)PerlIO_close(fp);
	if (len <= 0) {
	    if (S_ISDIR(PL_statcache.st_mode) && PL_op->op_type == OP_FTTEXT)
		RETPUSHNO;		/* special case NFS directories */
	    RETPUSHYES;		/* null file is anything */
	}
	s = tbuf;
    }

    /* now scan s to look for textiness */
    /*   XXX ASCII dependent code */

#if defined(DOSISH) || defined(USEMYBINMODE)
    /* ignore trailing ^Z on short files */
    if (len && len < (I32)sizeof(tbuf) && tbuf[len-1] == 26)
	--len;
#endif