X-Git-Url: https://perl5.git.perl.org/perl5.git/blobdiff_plain/75b6c4caab1abb3506eab9e8e512c69bbeb1c49f..a7fce7e16a936eb048fedb9b30adc592bcb2c657:/mg.c

diff --git a/mg.c b/mg.c
index 3f462ee..b04e24f 100644
--- a/mg.c
+++ b/mg.c
@@ -1,6 +1,7 @@
 /*    mg.c
  *
- *    Copyright (c) 1991-2003, Larry Wall
+ *    Copyright (C) 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999,
+ *    2000, 2001, 2002, 2003, 2004, 2005 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.
@@ -14,6 +15,24 @@
 
 /*
 =head1 Magical Functions
+
+"Magic" is special data attached to SV structures in order to give them
+"magical" properties.  When any Perl code tries to read from, or assign to,
+an SV marked as magical, it calls the 'get' or 'set' function associated
+with that SV's magic. A get is called prior to reading an SV, in order to
+give it a chance to update its internal value (get on $. writes the line
+number of the last read filehandle into to the SV's IV slot), while
+set is called after an SV has been written to, in order to allow it to make
+use of its changed value (set on $/ copies the SV's new value to the
+PL_rs global variable).
+
+Magic is implemented as a linked list of MAGIC structures attached to the
+SV. Each MAGIC struct holds the type of the magic, a pointer to an array
+of functions that implement the get(), set(), length() etc functions,
+plus space for some flags and pointers. For example, a tied variable has
+a MAGIC structure that contains a pointer to the object associated with the
+tie.
+
 */
 
 #include "EXTERN.h"
@@ -33,17 +52,18 @@
 #  include <sys/pstat.h>
 #endif
 
-/* if you only have signal() and it resets on each signal, FAKE_PERSISTENT_SIGNAL_HANDLERS fixes */
-#if !defined(HAS_SIGACTION) && defined(VMS)
-#  define  FAKE_PERSISTENT_SIGNAL_HANDLERS
-#endif
-/* if we're doing kill() with sys$sigprc on VMS, FAKE_DEFAULT_SIGNAL_HANDLERS */
-#if defined(KILL_BY_SIGPRC)
-#  define  FAKE_DEFAULT_SIGNAL_HANDLERS
-#endif
+Signal_t Perl_csighandler(int sig);
 
-static void restore_magic(pTHX_ void *p);
-static void unwind_handler_stack(pTHX_ void *p);
+static void restore_magic(pTHX_ const void *p);
+static void unwind_handler_stack(pTHX_ const void *p);
+
+#ifdef __Lynx__
+/* Missing protos on LynxOS */
+void setruid(uid_t id);
+void seteuid(uid_t id);
+void setrgid(uid_t id);
+void setegid(uid_t id);
+#endif
 
 /*
  * Use the "DESTRUCTOR" scope cleanup to reinstate magic.
@@ -90,9 +110,9 @@ Turns on the magical status of an SV.  See C<sv_magic>.
 void
 Perl_mg_magical(pTHX_ SV *sv)
 {
-    MAGIC* mg;
+    const MAGIC* mg;
     for (mg = SvMAGIC(sv); mg; mg = mg->mg_moremagic) {
-	MGVTBL* vtbl = mg->mg_virtual;
+	const MGVTBL* const vtbl = mg->mg_virtual;
 	if (vtbl) {
 	    if (vtbl->svt_get && !(mg->mg_flags & MGf_GSKIP))
 		SvGMAGICAL_on(sv);
@@ -115,9 +135,21 @@ Do magic after a value is retrieved from the SV.  See C<sv_magic>.
 int
 Perl_mg_get(pTHX_ SV *sv)
 {
-    int new = 0;
+    const I32 mgs_ix = SSNEW(sizeof(MGS));
+    const bool was_temp = (bool)SvTEMP(sv);
+    int have_new = 0;
     MAGIC *newmg, *head, *cur, *mg;
-    I32 mgs_ix = SSNEW(sizeof(MGS));
+    /* guard against sv having being freed midway by holding a private
+       reference. */
+
+    /* sv_2mortal has this side effect of turning on the TEMP flag, which can
+       cause the SV's buffer to get stolen (and maybe other stuff).
+       So restore it.
+    */
+    sv_2mortal(SvREFCNT_inc(sv));
+    if (!was_temp) {
+	SvTEMP_off(sv);
+    }
 
     save_magic(mgs_ix, sv);
 
@@ -127,10 +159,16 @@ Perl_mg_get(pTHX_ SV *sv)
 
     newmg = cur = head = mg = SvMAGIC(sv);
     while (mg) {
-	MGVTBL *vtbl = mg->mg_virtual;
+	const MGVTBL * const vtbl = mg->mg_virtual;
 
 	if (!(mg->mg_flags & MGf_GSKIP) && vtbl && vtbl->svt_get) {
 	    CALL_FPTR(vtbl->svt_get)(aTHX_ sv, mg);
+
+	    /* guard against magic having been deleted - eg FETCH calling
+	     * untie */
+	    if (!SvMAGIC(sv))
+		break;
+
 	    /* Don't restore the flags for this entry if it was deleted. */
 	    if (mg->mg_flags & MGf_GSKIP)
 		(SSPTR(mgs_ix, MGS *))->mgs_flags = 0;
@@ -138,25 +176,31 @@ Perl_mg_get(pTHX_ SV *sv)
 
 	mg = mg->mg_moremagic;
 
-	if (new) {
+	if (have_new) {
 	    /* Have we finished with the new entries we saw? Start again
 	       where we left off (unless there are more new entries). */
 	    if (mg == head) {
-		new  = 0;
+		have_new = 0;
 		mg   = cur;
 		head = newmg;
 	    }
 	}
 
 	/* Were any new entries added? */
-	if (!new && (newmg = SvMAGIC(sv)) != head) {
-	    new = 1;
+	if (!have_new && (newmg = SvMAGIC(sv)) != head) {
+	    have_new = 1;
 	    cur = mg;
 	    mg  = newmg;
 	}
     }
 
     restore_magic(aTHX_ INT2PTR(void *, (IV)mgs_ix));
+
+    if (SvREFCNT(sv) == 1) {
+	/* We hold the last reference to this SV, which implies that the
+	   SV was deleted as a side effect of the routines we called.  */
+	SvOK_off(sv);
+    }
     return 0;
 }
 
@@ -171,15 +215,14 @@ Do magic after a value is assigned to the SV.  See C<sv_magic>.
 int
 Perl_mg_set(pTHX_ SV *sv)
 {
-    I32 mgs_ix;
+    const I32 mgs_ix = SSNEW(sizeof(MGS));
     MAGIC* mg;
     MAGIC* nextmg;
 
-    mgs_ix = SSNEW(sizeof(MGS));
     save_magic(mgs_ix, sv);
 
     for (mg = SvMAGIC(sv); mg; mg = nextmg) {
-	MGVTBL* vtbl = mg->mg_virtual;
+        const MGVTBL* vtbl = mg->mg_virtual;
 	nextmg = mg->mg_moremagic;	/* it may delete itself */
 	if (mg->mg_flags & MGf_GSKIP) {
 	    mg->mg_flags &= ~MGf_GSKIP;	/* setting requires another read */
@@ -208,11 +251,9 @@ Perl_mg_length(pTHX_ SV *sv)
     STRLEN len;
 
     for (mg = SvMAGIC(sv); mg; mg = mg->mg_moremagic) {
-	MGVTBL* vtbl = mg->mg_virtual;
+        const MGVTBL * const vtbl = mg->mg_virtual;
 	if (vtbl && vtbl->svt_len) {
-            I32 mgs_ix;
-
-	    mgs_ix = SSNEW(sizeof(MGS));
+            const I32 mgs_ix = SSNEW(sizeof(MGS));
 	    save_magic(mgs_ix, sv);
 	    /* omit MGf_GSKIP -- not changed here */
 	    len = CALL_FPTR(vtbl->svt_len)(aTHX_ sv, mg);
@@ -221,8 +262,7 @@ Perl_mg_length(pTHX_ SV *sv)
 	}
     }
 
-    if (DO_UTF8(sv))
-    {
+    if (DO_UTF8(sv)) {
         U8 *s = (U8*)SvPV(sv, len);
         len = Perl_utf8_length(aTHX_ s, s + len);
     }
@@ -235,14 +275,12 @@ I32
 Perl_mg_size(pTHX_ SV *sv)
 {
     MAGIC* mg;
-    I32 len;
 
     for (mg = SvMAGIC(sv); mg; mg = mg->mg_moremagic) {
-	MGVTBL* vtbl = mg->mg_virtual;
+        const MGVTBL* const vtbl = mg->mg_virtual;
 	if (vtbl && vtbl->svt_len) {
-            I32 mgs_ix;
-
-	    mgs_ix = SSNEW(sizeof(MGS));
+            const I32 mgs_ix = SSNEW(sizeof(MGS));
+            I32 len;
 	    save_magic(mgs_ix, sv);
 	    /* omit MGf_GSKIP -- not changed here */
 	    len = CALL_FPTR(vtbl->svt_len)(aTHX_ sv, mg);
@@ -253,8 +291,7 @@ Perl_mg_size(pTHX_ SV *sv)
 
     switch(SvTYPE(sv)) {
 	case SVt_PVAV:
-	    len = AvFILLp((AV *) sv); /* Fallback to non-tied array */
-	    return len;
+	    return AvFILLp((AV *) sv); /* Fallback to non-tied array */
 	case SVt_PVHV:
 	    /* FIXME */
 	default:
@@ -275,14 +312,13 @@ Clear something magical that the SV represents.  See C<sv_magic>.
 int
 Perl_mg_clear(pTHX_ SV *sv)
 {
-    I32 mgs_ix;
+    const I32 mgs_ix = SSNEW(sizeof(MGS));
     MAGIC* mg;
 
-    mgs_ix = SSNEW(sizeof(MGS));
     save_magic(mgs_ix, sv);
 
     for (mg = SvMAGIC(sv); mg; mg = mg->mg_moremagic) {
-	MGVTBL* vtbl = mg->mg_virtual;
+        const MGVTBL* const vtbl = mg->mg_virtual;
 	/* omit GSKIP -- never set here */
 
 	if (vtbl && vtbl->svt_clear)
@@ -302,14 +338,14 @@ Finds the magic pointer for type matching the SV.  See C<sv_magic>.
 */
 
 MAGIC*
-Perl_mg_find(pTHX_ SV *sv, int type)
+Perl_mg_find(pTHX_ const SV *sv, int type)
 {
-    MAGIC* mg;
-    if (!sv)
-        return 0;
-    for (mg = SvMAGIC(sv); mg; mg = mg->mg_moremagic) {
-	if (mg->mg_type == type)
-	    return mg;
+    if (sv) {
+        MAGIC *mg;
+        for (mg = SvMAGIC(sv); mg; mg = mg->mg_moremagic) {
+            if (mg->mg_type == type)
+                return mg;
+        }
     }
     return 0;
 }
@@ -328,7 +364,7 @@ Perl_mg_copy(pTHX_ SV *sv, SV *nsv, const char *key, I32 klen)
     int count = 0;
     MAGIC* mg;
     for (mg = SvMAGIC(sv); mg; mg = mg->mg_moremagic) {
-	MGVTBL* vtbl = mg->mg_virtual;
+        const MGVTBL* const vtbl = mg->mg_virtual;
 	if ((mg->mg_flags & MGf_COPY) && vtbl->svt_copy){
 	    count += CALL_FPTR(vtbl->svt_copy)(aTHX_ sv, mg, nsv, key, klen);
 	}
@@ -358,12 +394,12 @@ Perl_mg_free(pTHX_ SV *sv)
     MAGIC* mg;
     MAGIC* moremagic;
     for (mg = SvMAGIC(sv); mg; mg = moremagic) {
-	MGVTBL* vtbl = mg->mg_virtual;
+        const MGVTBL* const vtbl = mg->mg_virtual;
 	moremagic = mg->mg_moremagic;
 	if (vtbl && vtbl->svt_free)
 	    CALL_FPTR(vtbl->svt_free)(aTHX_ sv, mg);
 	if (mg->mg_ptr && mg->mg_type != PERL_MAGIC_regex_global) {
-	    if (mg->mg_len > 0)
+	    if (mg->mg_len > 0 || mg->mg_type == PERL_MAGIC_utf8)
 		Safefree(mg->mg_ptr);
 	    else if (mg->mg_len == HEf_SVKEY)
 		SvREFCNT_dec((SV*)mg->mg_ptr);
@@ -372,19 +408,17 @@ Perl_mg_free(pTHX_ SV *sv)
 	    SvREFCNT_dec(mg->mg_obj);
 	Safefree(mg);
     }
-    SvMAGIC(sv) = 0;
+    SvMAGIC_set(sv, NULL);
     return 0;
 }
 
-
-#if !defined(NSIG) || defined(M_UNIX) || defined(M_XENIX)
 #include <signal.h>
-#endif
 
 U32
 Perl_magic_regdata_cnt(pTHX_ SV *sv, MAGIC *mg)
 {
-    register REGEXP *rx;
+    register const REGEXP *rx;
+    (void)sv;
 
     if (PL_curpm && (rx = PM_GETRE(PL_curpm))) {
 	if (mg->mg_obj)		/* @+ */
@@ -399,20 +433,19 @@ Perl_magic_regdata_cnt(pTHX_ SV *sv, MAGIC *mg)
 int
 Perl_magic_regdatum_get(pTHX_ SV *sv, MAGIC *mg)
 {
-    register I32 paren;
-    register I32 s;
-    register I32 i;
     register REGEXP *rx;
-    I32 t;
 
     if (PL_curpm && (rx = PM_GETRE(PL_curpm))) {
-	paren = mg->mg_len;
+        register const I32 paren = mg->mg_len;
+        register I32 s;
+        register I32 t;
 	if (paren < 0)
 	    return 0;
 	if (paren <= (I32)rx->nparens &&
 	    (s = rx->startp[paren]) != -1 &&
 	    (t = rx->endp[paren]) != -1)
 	    {
+                register I32 i;
 		if (mg->mg_obj)		/* @+ */
 		    i = t;
 		else			/* @- */
@@ -433,9 +466,14 @@ Perl_magic_regdatum_get(pTHX_ SV *sv, MAGIC *mg)
 int
 Perl_magic_regdatum_set(pTHX_ SV *sv, MAGIC *mg)
 {
+    (void)sv; (void)mg;
     Perl_croak(aTHX_ PL_no_modify);
     /* NOT REACHED */
+#ifndef HASATTRIBUTE
+    /* No __attribute__, so the compiler doesn't know that croak never returns
+     */
     return 0;
+#endif
 }
 
 U32
@@ -443,7 +481,7 @@ Perl_magic_len(pTHX_ SV *sv, MAGIC *mg)
 {
     register I32 paren;
     register I32 i;
-    register REGEXP *rx;
+    register const REGEXP *rx;
     I32 s1, t1;
 
     switch (*mg->mg_ptr) {
@@ -473,12 +511,12 @@ Perl_magic_len(pTHX_ SV *sv, MAGIC *mg)
 	    }
 	    else {
 		if (ckWARN(WARN_UNINITIALIZED))
-		    report_uninit();
+		    report_uninit(sv);
 	    }
 	}
 	else {
 	    if (ckWARN(WARN_UNINITIALIZED))
-		report_uninit();
+		report_uninit(sv);
 	}
 	return 0;
     case '+':
@@ -533,8 +571,9 @@ Perl_magic_len(pTHX_ SV *sv, MAGIC *mg)
 int
 Perl_magic_get(pTHX_ SV *sv, MAGIC *mg)
 {
+    dVAR;
     register I32 paren;
-    register char *s;
+    register char *s = NULL;
     register I32 i;
     register REGEXP *rx;
 
@@ -548,9 +587,6 @@ Perl_magic_get(pTHX_ SV *sv, MAGIC *mg)
 
     case '\004':		/* ^D */
 	sv_setiv(sv, (IV)(PL_debug & DEBUG_MASK));
-#if defined(YYDEBUG) && defined(DEBUGGING)
-	PL_yydebug = DEBUG_p_TEST;
-#endif
 	break;
     case '\005':  /* ^E */
 	 if (*(mg->mg_ptr+1) == '\0') {
@@ -602,8 +638,12 @@ Perl_magic_get(pTHX_ SV *sv, MAGIC *mg)
 		  SetLastError(dwErr);
 	     }
 #else
-	     sv_setnv(sv, (NV)errno);
-	     sv_setpv(sv, errno ? Strerror(errno) : "");
+	     {
+		 int saveerrno = errno;
+		 sv_setnv(sv, (NV)errno);
+		 sv_setpv(sv, errno ? Strerror(errno) : "");
+		 errno = saveerrno;
+	     }
 #endif
 #endif
 #endif
@@ -626,8 +666,10 @@ Perl_magic_get(pTHX_ SV *sv, MAGIC *mg)
 	    sv_setsv(sv, &PL_sv_undef);
 	break;
     case '\017':		/* ^O & ^OPEN */
-	if (*(mg->mg_ptr+1) == '\0')
+	if (*(mg->mg_ptr+1) == '\0') {
 	    sv_setpv(sv, PL_osname);
+	    SvTAINTED_off(sv);
+	}
 	else if (strEQ(mg->mg_ptr, "\017PEN")) {
 	    if (!PL_compiling.cop_io)
 		sv_setsv(sv, &PL_sv_undef);
@@ -642,7 +684,7 @@ Perl_magic_get(pTHX_ SV *sv, MAGIC *mg)
     case '\023':		/* ^S */
         if (*(mg->mg_ptr+1) == '\0') {
 	    if (PL_lex_state != LEX_NOTPARSING)
-		(void)SvOK_off(sv);
+		SvOK_off(sv);
 	    else if (PL_in_eval)
  		sv_setiv(sv, PL_in_eval & ~(EVAL_INREQUIRE));
 	    else
@@ -662,9 +704,11 @@ Perl_magic_get(pTHX_ SV *sv, MAGIC *mg)
 		    ? (PL_taint_warn || PL_unsafe ? -1 : 1)
 		    : 0);
         break;
-    case '\025':		/* $^UNICODE */
+    case '\025':		/* $^UNICODE, $^UTF8LOCALE */
         if (strEQ(mg->mg_ptr, "\025NICODE"))
 	    sv_setuv(sv, (UV) PL_unicode);
+        else if (strEQ(mg->mg_ptr, "\025TF8LOCALE"))
+	    sv_setuv(sv, (UV) PL_utf8locale);
         break;
     case '\027':		/* ^W  & $^WARNING_BITS */
 	if (*(mg->mg_ptr+1) == '\0')
@@ -725,11 +769,11 @@ Perl_magic_get(pTHX_ SV *sv, MAGIC *mg)
 			    MAGIC* mg = SvMAGIC(sv);
 			    MAGIC* mgt;
 			    PL_tainted = 1;
-			    SvMAGIC(sv) = mg->mg_moremagic;
+			    SvMAGIC_set(sv, mg->mg_moremagic);
 			    SvTAINT(sv);
 			    if ((mgt = SvMAGIC(sv))) {
 				mg->mg_moremagic = mgt;
-				SvMAGIC(sv) = mg;
+				SvMAGIC_set(sv, mg);
 			    }
 			} else
 			    SvTAINTED_off(sv);
@@ -792,7 +836,8 @@ Perl_magic_get(pTHX_ SV *sv, MAGIC *mg)
 	}
 	break;
     case '^':
-	s = IoTOP_NAME(GvIOp(PL_defoutgv));
+	if (GvIOp(PL_defoutgv))
+	    s = IoTOP_NAME(GvIOp(PL_defoutgv));
 	if (s)
 	    sv_setpv(sv,s);
 	else {
@@ -801,20 +846,24 @@ Perl_magic_get(pTHX_ SV *sv, MAGIC *mg)
 	}
 	break;
     case '~':
-	s = IoFMT_NAME(GvIOp(PL_defoutgv));
+	if (GvIOp(PL_defoutgv))
+	    s = IoFMT_NAME(GvIOp(PL_defoutgv));
 	if (!s)
 	    s = GvENAME(PL_defoutgv);
 	sv_setpv(sv,s);
 	break;
 #ifndef lint
     case '=':
-	sv_setiv(sv, (IV)IoPAGE_LEN(GvIOp(PL_defoutgv)));
+	if (GvIOp(PL_defoutgv))
+	    sv_setiv(sv, (IV)IoPAGE_LEN(GvIOp(PL_defoutgv)));
 	break;
     case '-':
-	sv_setiv(sv, (IV)IoLINES_LEFT(GvIOp(PL_defoutgv)));
+	if (GvIOp(PL_defoutgv))
+	    sv_setiv(sv, (IV)IoLINES_LEFT(GvIOp(PL_defoutgv)));
 	break;
     case '%':
-	sv_setiv(sv, (IV)IoPAGE(GvIOp(PL_defoutgv)));
+	if (GvIOp(PL_defoutgv))
+	    sv_setiv(sv, (IV)IoPAGE(GvIOp(PL_defoutgv)));
 	break;
 #endif
     case ':':
@@ -825,7 +874,8 @@ Perl_magic_get(pTHX_ SV *sv, MAGIC *mg)
 	WITH_THR(sv_setiv(sv, (IV)PL_curcop->cop_arybase));
 	break;
     case '|':
-	sv_setiv(sv, (IV)(IoFLAGS(GvIOp(PL_defoutgv)) & IOf_FLUSH) != 0 );
+	if (GvIOp(PL_defoutgv))
+	    sv_setiv(sv, (IV)(IoFLAGS(GvIOp(PL_defoutgv)) & IOf_FLUSH) != 0 );
 	break;
     case ',':
 	break;
@@ -883,8 +933,6 @@ Perl_magic_get(pTHX_ SV *sv, MAGIC *mg)
 #endif
 	(void)SvIOK_on(sv);	/* what a wonderful hack! */
 	break;
-    case '*':
-	break;
 #ifndef MACOS_TRADITIONAL
     case '0':
 	break;
@@ -906,6 +954,7 @@ Perl_magic_getuvar(pTHX_ SV *sv, MAGIC *mg)
 int
 Perl_magic_setenv(pTHX_ SV *sv, MAGIC *mg)
 {
+    dVAR;
     register char *s;
     char *ptr;
     STRLEN len, klen;
@@ -983,6 +1032,7 @@ int
 Perl_magic_clearenv(pTHX_ SV *sv, MAGIC *mg)
 {
     STRLEN n_a;
+    (void)sv;
     my_setenv(MgPV(mg,n_a),Nullch);
     return 0;
 }
@@ -990,7 +1040,7 @@ Perl_magic_clearenv(pTHX_ SV *sv, MAGIC *mg)
 int
 Perl_magic_set_all_env(pTHX_ SV *sv, MAGIC *mg)
 {
-#if defined(VMS)
+#if defined(VMS) || defined(EPOC) || defined(SYMBIAN)
     Perl_die(aTHX_ "Can't make list assignment to %%ENV on this system");
 #else
     if (PL_localizing) {
@@ -1011,7 +1061,9 @@ Perl_magic_set_all_env(pTHX_ SV *sv, MAGIC *mg)
 int
 Perl_magic_clear_all_env(pTHX_ SV *sv, MAGIC *mg)
 {
-#if defined(VMS) || defined(EPOC)
+    dVAR;
+#ifndef PERL_MICRO
+#if defined(VMS) || defined(EPOC) || defined(SYMBIAN)
     Perl_die(aTHX_ "Can't make list assignment to %%ENV on this system");
 #else
 #  if defined(PERL_IMPLICIT_SYS) || defined(WIN32)
@@ -1024,6 +1076,7 @@ Perl_magic_clear_all_env(pTHX_ SV *sv, MAGIC *mg)
 #      endif
     {
 #      ifndef PERL_USE_SAFE_PUTENV
+    if (!PL_use_safe_putenv) {
     I32 i;
 
     if (environ == PL_origenviron)
@@ -1031,26 +1084,20 @@ Perl_magic_clear_all_env(pTHX_ SV *sv, MAGIC *mg)
     else
 	for (i = 0; environ[i]; i++)
 	    safesysfree(environ[i]);
+    }
 #      endif /* PERL_USE_SAFE_PUTENV */
 
     environ[0] = Nullch;
     }
 #    endif /* USE_ENVIRON_ARRAY */
 #   endif /* PERL_IMPLICIT_SYS || WIN32 */
-#endif /* VMS || EPC */
+#endif /* VMS || EPOC */
+#endif /* !PERL_MICRO */
+    (void)sv;
+    (void)mg;
     return 0;
 }
 
-#if defined(FAKE_PERSISTENT_SIGNAL_HANDLERS)||defined(FAKE_DEFAULT_SIGNAL_HANDLERS)
-static int sig_handlers_initted = 0;
-#endif
-#ifdef FAKE_PERSISTENT_SIGNAL_HANDLERS
-static int sig_ignoring[SIG_SIZE];      /* which signals we are ignoring */
-#endif
-#ifdef FAKE_DEFAULT_SIGNAL_HANDLERS
-static int sig_defaulting[SIG_SIZE];
-#endif
-
 #ifndef PERL_MICRO
 #ifdef HAS_SIGPROCMASK
 static void
@@ -1067,17 +1114,17 @@ Perl_magic_getsig(pTHX_ SV *sv, MAGIC *mg)
     STRLEN n_a;
     /* Are we fetching a signal entry? */
     i = whichsig(MgPV(mg,n_a));
-    if (i) {
+    if (i > 0) {
     	if(PL_psig_ptr[i])
     	    sv_setsv(sv,PL_psig_ptr[i]);
     	else {
     	    Sighandler_t sigstate;
     	    sigstate = rsignal_state(i);
 #ifdef FAKE_PERSISTENT_SIGNAL_HANDLERS
-    	    if (sig_handlers_initted && sig_ignoring[i]) sigstate = SIG_IGN;
+    	    if (PL_sig_handlers_initted && PL_sig_ignoring[i]) sigstate = SIG_IGN;
 #endif
 #ifdef FAKE_DEFAULT_SIGNAL_HANDLERS
-    	    if (sig_handlers_initted && sig_defaulting[i]) sigstate = SIG_DFL;
+    	    if (PL_sig_handlers_initted && PL_sig_defaulting[i]) sigstate = SIG_DFL;
 #endif
     	    /* cache state so we don't fetch it again */
     	    if(sigstate == SIG_IGN)
@@ -1096,20 +1143,20 @@ Perl_magic_clearsig(pTHX_ SV *sv, MAGIC *mg)
     /* XXX Some of this code was copied from Perl_magic_setsig. A little
      * refactoring might be in order.
      */
-    register char *s;
+    dVAR;
     STRLEN n_a;
-    SV* to_dec;
-    s = MgPV(mg,n_a);
+    register const char *s = MgPV(mg,n_a);
+    (void)sv;
     if (*s == '_') {
-	SV** svp;
+	SV** svp = 0;
 	if (strEQ(s,"__DIE__"))
 	    svp = &PL_diehook;
 	else if (strEQ(s,"__WARN__"))
 	    svp = &PL_warnhook;
 	else
 	    Perl_croak(aTHX_ "No such hook: %s", s);
-	if (*svp) {
-	    to_dec = *svp;
+	if (svp && *svp) {
+            SV *to_dec = *svp;
 	    *svp = 0;
     	    SvREFCNT_dec(to_dec);
 	}
@@ -1118,7 +1165,7 @@ Perl_magic_clearsig(pTHX_ SV *sv, MAGIC *mg)
 	I32 i;
 	/* Are we clearing a signal entry? */
 	i = whichsig(s);
-	if (i) {
+	if (i > 0) {
 #ifdef HAS_SIGPROCMASK
 	    sigset_t set, save;
 	    SV* save_sv;
@@ -1133,11 +1180,11 @@ Perl_magic_clearsig(pTHX_ SV *sv, MAGIC *mg)
 #endif
 	    PERL_ASYNC_CHECK();
 #if defined(FAKE_PERSISTENT_SIGNAL_HANDLERS) || defined(FAKE_DEFAULT_SIGNAL_HANDLERS)
-	    if (!sig_handlers_initted) Perl_csighandler_init();
+	    if (!PL_sig_handlers_initted) Perl_csighandler_init();
 #endif
 #ifdef FAKE_DEFAULT_SIGNAL_HANDLERS
-	    sig_defaulting[i] = 1;
-	    (void)rsignal(i, &Perl_csighandler);
+	    PL_sig_defaulting[i] = 1;
+	    (void)rsignal(i, PL_csighandlerp);
 #else
 	    (void)rsignal(i, SIG_DFL);
 #endif
@@ -1146,7 +1193,7 @@ Perl_magic_clearsig(pTHX_ SV *sv, MAGIC *mg)
     		PL_psig_name[i]=0;
     	    }
     	    if(PL_psig_ptr[i]) {
-		to_dec=PL_psig_ptr[i];
+                SV *to_dec=PL_psig_ptr[i];
     		PL_psig_ptr[i]=0;
 		LEAVE;
     		SvREFCNT_dec(to_dec);
@@ -1158,8 +1205,8 @@ Perl_magic_clearsig(pTHX_ SV *sv, MAGIC *mg)
     return 0;
 }
 
-void
-Perl_raise_signal(pTHX_ int sig)
+static void
+S_raise_signal(pTHX_ int sig)
 {
     /* Set a flag to say this signal is pending */
     PL_psig_pend[sig]++;
@@ -1176,11 +1223,11 @@ Perl_csighandler(int sig)
     dTHX;
 #endif
 #ifdef FAKE_PERSISTENT_SIGNAL_HANDLERS
-    (void) rsignal(sig, &Perl_csighandler);
-    if (sig_ignoring[sig]) return;
+    (void) rsignal(sig, PL_csighandlerp);
+    if (PL_sig_ignoring[sig]) return;
 #endif
 #ifdef FAKE_DEFAULT_SIGNAL_HANDLERS
-    if (sig_defaulting[sig])
+    if (PL_sig_defaulting[sig])
 #ifdef KILL_BY_SIGPRC
             exit((Perl_sig_to_vmscondition(sig)&STS$M_COND_ID)|STS$K_SEVERE|STS$M_INHIB_MSG);
 #else
@@ -1192,7 +1239,7 @@ Perl_csighandler(int sig)
 	 * with risk we may be in malloc() etc. */
 	(*PL_sighandlerp)(sig);
    else
-	Perl_raise_signal(aTHX_ sig);
+	S_raise_signal(aTHX_ sig);
 }
 
 #if defined(FAKE_PERSISTENT_SIGNAL_HANDLERS) || defined(FAKE_DEFAULT_SIGNAL_HANDLERS)
@@ -1200,19 +1247,19 @@ void
 Perl_csighandler_init(void)
 {
     int sig;
-    if (sig_handlers_initted) return;
+    if (PL_sig_handlers_initted) return;
 
     for (sig = 1; sig < SIG_SIZE; sig++) {
 #ifdef FAKE_DEFAULT_SIGNAL_HANDLERS
         dTHX;
-        sig_defaulting[sig] = 1;
-        (void) rsignal(sig, &Perl_csighandler);
+        PL_sig_defaulting[sig] = 1;
+        (void) rsignal(sig, PL_csighandlerp);
 #endif
 #ifdef FAKE_PERSISTENT_SIGNAL_HANDLERS
-        sig_ignoring[sig] = 0;
+        PL_sig_ignoring[sig] = 0;
 #endif
     }
-    sig_handlers_initted = 1;
+    PL_sig_handlers_initted = 1;
 }
 #endif
 
@@ -1235,7 +1282,7 @@ Perl_despatch_signals(pTHX)
 int
 Perl_magic_setsig(pTHX_ SV *sv, MAGIC *mg)
 {
-    register char *s;
+    dVAR;
     I32 i;
     SV** svp = 0;
     /* Need to be careful with SvREFCNT_dec(), because that can have side
@@ -1249,7 +1296,7 @@ Perl_magic_setsig(pTHX_ SV *sv, MAGIC *mg)
     SV* save_sv;
 #endif
 
-    s = MgPV(mg,len);
+    register const char *s = MgPV(mg,len);
     if (*s == '_') {
 	if (strEQ(s,"__DIE__"))
 	    svp = &PL_diehook;
@@ -1265,7 +1312,7 @@ Perl_magic_setsig(pTHX_ SV *sv, MAGIC *mg)
     }
     else {
 	i = whichsig(s);	/* ...no, a brick */
-	if (!i) {
+	if (i < 0) {
 	    if (ckWARN(WARN_SIGNAL))
 		Perl_warner(aTHX_ packWARN(WARN_SIGNAL), "No such signal: SIG%s", s);
 	    return 0;
@@ -1282,13 +1329,13 @@ Perl_magic_setsig(pTHX_ SV *sv, MAGIC *mg)
 #endif
 	PERL_ASYNC_CHECK();
 #if defined(FAKE_PERSISTENT_SIGNAL_HANDLERS) || defined(FAKE_DEFAULT_SIGNAL_HANDLERS)
-	if (!sig_handlers_initted) Perl_csighandler_init();
+	if (!PL_sig_handlers_initted) Perl_csighandler_init();
 #endif
 #ifdef FAKE_PERSISTENT_SIGNAL_HANDLERS
-	sig_ignoring[i] = 0;
+	PL_sig_ignoring[i] = 0;
 #endif
 #ifdef FAKE_DEFAULT_SIGNAL_HANDLERS
-	sig_defaulting[i] = 0;
+	PL_sig_defaulting[i] = 0;
 #endif
 	SvREFCNT_dec(PL_psig_name[i]);
 	to_dec = PL_psig_ptr[i];
@@ -1299,7 +1346,7 @@ Perl_magic_setsig(pTHX_ SV *sv, MAGIC *mg)
     }
     if (SvTYPE(sv) == SVt_PVGV || SvROK(sv)) {
 	if (i) {
-	    (void)rsignal(i, &Perl_csighandler);
+	    (void)rsignal(i, PL_csighandlerp);
 #ifdef HAS_SIGPROCMASK
 	    LEAVE;
 #endif
@@ -1314,8 +1361,8 @@ Perl_magic_setsig(pTHX_ SV *sv, MAGIC *mg)
     if (strEQ(s,"IGNORE")) {
 	if (i) {
 #ifdef FAKE_PERSISTENT_SIGNAL_HANDLERS
-	    sig_ignoring[i] = 1;
-	    (void)rsignal(i, &Perl_csighandler);
+	    PL_sig_ignoring[i] = 1;
+	    (void)rsignal(i, PL_csighandlerp);
 #else
 	    (void)rsignal(i, SIG_IGN);
 #endif
@@ -1325,8 +1372,8 @@ Perl_magic_setsig(pTHX_ SV *sv, MAGIC *mg)
 	if (i)
 #ifdef FAKE_DEFAULT_SIGNAL_HANDLERS
 	  {
-	    sig_defaulting[i] = 1;
-	    (void)rsignal(i, &Perl_csighandler);
+	    PL_sig_defaulting[i] = 1;
+	    (void)rsignal(i, PL_csighandlerp);
 	  }
 #else
 	    (void)rsignal(i, SIG_DFL);
@@ -1341,7 +1388,7 @@ Perl_magic_setsig(pTHX_ SV *sv, MAGIC *mg)
 	if (!strchr(s,':') && !strchr(s,'\''))
 	    sv_insert(sv, 0, 0, "main::", 6);
 	if (i)
-	    (void)rsignal(i, &Perl_csighandler);
+	    (void)rsignal(i, PL_csighandlerp);
 	else
 	    *svp = SvREFCNT_inc(sv);
     }
@@ -1358,6 +1405,8 @@ Perl_magic_setsig(pTHX_ SV *sv, MAGIC *mg)
 int
 Perl_magic_setisa(pTHX_ SV *sv, MAGIC *mg)
 {
+    (void)sv;
+    (void)mg;
     PL_sub_generation++;
     return 0;
 }
@@ -1365,6 +1414,8 @@ Perl_magic_setisa(pTHX_ SV *sv, MAGIC *mg)
 int
 Perl_magic_setamagic(pTHX_ SV *sv, MAGIC *mg)
 {
+    (void)sv;
+    (void)mg;
     /* HV_badAMAGIC_on(Sv_STASH(sv)); */
     PL_amagic_generation++;
 
@@ -1374,8 +1425,9 @@ Perl_magic_setamagic(pTHX_ SV *sv, MAGIC *mg)
 int
 Perl_magic_getnkeys(pTHX_ SV *sv, MAGIC *mg)
 {
-    HV *hv = (HV*)LvTARG(sv);
+    HV * const hv = (HV*)LvTARG(sv);
     I32 i = 0;
+    (void)mg;
 
     if (hv) {
          (void) hv_iterinit(hv);
@@ -1394,6 +1446,7 @@ Perl_magic_getnkeys(pTHX_ SV *sv, MAGIC *mg)
 int
 Perl_magic_setnkeys(pTHX_ SV *sv, MAGIC *mg)
 {
+    (void)mg;
     if (LvTARG(sv)) {
 	hv_ksplit((HV*)LvTARG(sv), SvIV(sv));
     }
@@ -1402,7 +1455,7 @@ Perl_magic_setnkeys(pTHX_ SV *sv, MAGIC *mg)
 
 /* caller is responsible for stack switching/cleanup */
 STATIC int
-S_magic_methcall(pTHX_ SV *sv, MAGIC *mg, char *meth, I32 flags, int n, SV *val)
+S_magic_methcall(pTHX_ SV *sv, const MAGIC *mg, const char *meth, I32 flags, int n, SV *val)
 {
     dSP;
 
@@ -1429,9 +1482,9 @@ S_magic_methcall(pTHX_ SV *sv, MAGIC *mg, char *meth, I32 flags, int n, SV *val)
 }
 
 STATIC int
-S_magic_methpack(pTHX_ SV *sv, MAGIC *mg, char *meth)
+S_magic_methpack(pTHX_ SV *sv, const MAGIC *mg, const char *meth)
 {
-    dSP;
+    dVAR; dSP;
 
     ENTER;
     SAVETMPS;
@@ -1450,16 +1503,16 @@ S_magic_methpack(pTHX_ SV *sv, MAGIC *mg, char *meth)
 int
 Perl_magic_getpack(pTHX_ SV *sv, MAGIC *mg)
 {
-    magic_methpack(sv,mg,"FETCH");
     if (mg->mg_ptr)
 	mg->mg_flags |= MGf_GSKIP;
+    magic_methpack(sv,mg,"FETCH");
     return 0;
 }
 
 int
 Perl_magic_setpack(pTHX_ SV *sv, MAGIC *mg)
 {
-    dSP;
+    dVAR; dSP;
     ENTER;
     PUSHSTACKi(PERLSI_MAGIC);
     magic_methcall(sv, mg, "STORE", G_SCALAR|G_DISCARD, 3, sv);
@@ -1478,7 +1531,7 @@ Perl_magic_clearpack(pTHX_ SV *sv, MAGIC *mg)
 U32
 Perl_magic_sizepack(pTHX_ SV *sv, MAGIC *mg)
 {
-    dSP;
+    dVAR; dSP;
     U32 retval = 0;
 
     ENTER;
@@ -1497,7 +1550,7 @@ Perl_magic_sizepack(pTHX_ SV *sv, MAGIC *mg)
 int
 Perl_magic_wipepack(pTHX_ SV *sv, MAGIC *mg)
 {
-    dSP;
+    dVAR; dSP;
 
     ENTER;
     PUSHSTACKi(PERLSI_MAGIC);
@@ -1507,14 +1560,15 @@ Perl_magic_wipepack(pTHX_ SV *sv, MAGIC *mg)
     call_method("CLEAR", G_SCALAR|G_DISCARD);
     POPSTACK;
     LEAVE;
+
     return 0;
 }
 
 int
 Perl_magic_nextpack(pTHX_ SV *sv, MAGIC *mg, SV *key)
 {
-    dSP;
-    const char *meth = SvOK(key) ? "NEXTKEY" : "FIRSTKEY";
+    dVAR; dSP;
+    const char * const meth = SvOK(key) ? "NEXTKEY" : "FIRSTKEY";
 
     ENTER;
     SAVETMPS;
@@ -1541,6 +1595,41 @@ Perl_magic_existspack(pTHX_ SV *sv, MAGIC *mg)
     return magic_methpack(sv,mg,"EXISTS");
 }
 
+SV *
+Perl_magic_scalarpack(pTHX_ HV *hv, MAGIC *mg)
+{
+    dVAR; dSP;
+    SV *retval = &PL_sv_undef;
+    SV *tied = SvTIED_obj((SV*)hv, mg);
+    HV *pkg = SvSTASH((SV*)SvRV(tied));
+   
+    if (!gv_fetchmethod_autoload(pkg, "SCALAR", FALSE)) {
+        SV *key;
+        if (HvEITER(hv))
+            /* we are in an iteration so the hash cannot be empty */
+            return &PL_sv_yes;
+        /* no xhv_eiter so now use FIRSTKEY */
+        key = sv_newmortal();
+        magic_nextpack((SV*)hv, mg, key);
+        HvEITER(hv) = NULL;     /* need to reset iterator */
+        return SvOK(key) ? &PL_sv_yes : &PL_sv_no;
+    }
+   
+    /* there is a SCALAR method that we can call */
+    ENTER;
+    PUSHSTACKi(PERLSI_MAGIC);
+    PUSHMARK(SP);
+    EXTEND(SP, 1);
+    PUSHs(tied);
+    PUTBACK;
+
+    if (call_method("SCALAR", G_SCALAR))
+        retval = *PL_stack_sp--; 
+    POPSTACK;
+    LEAVE;
+    return retval;
+}
+
 int
 Perl_magic_setdbline(pTHX_ SV *sv, MAGIC *mg)
 {
@@ -1593,7 +1682,7 @@ Perl_magic_getpos(pTHX_ SV *sv, MAGIC *mg)
 	    return 0;
 	}
     }
-    (void)SvOK_off(sv);
+    SvOK_off(sv);
     return 0;
 }
 
@@ -1652,6 +1741,7 @@ Perl_magic_setpos(pTHX_ SV *sv, MAGIC *mg)
 int
 Perl_magic_getglob(pTHX_ SV *sv, MAGIC *mg)
 {
+    (void)mg;
     if (SvFAKE(sv)) {			/* FAKE globs can get coerced */
 	SvFAKE_off(sv);
 	gv_efullname3(sv,((GV*)sv), "*");
@@ -1665,16 +1755,12 @@ Perl_magic_getglob(pTHX_ SV *sv, MAGIC *mg)
 int
 Perl_magic_setglob(pTHX_ SV *sv, MAGIC *mg)
 {
-    register char *s;
     GV* gv;
-    STRLEN n_a;
-
+    (void)mg;
+ 
     if (!SvOK(sv))
 	return 0;
-    s = SvPV(sv, n_a);
-    if (*s == '*' && s[1])
-	s++;
-    gv = gv_fetchpv(s,TRUE, SVt_PVGV);
+    gv = gv_fetchsv(sv,TRUE, SVt_PVGV);
     if (sv == (SV*)gv)
 	return 0;
     if (GvGP(sv))
@@ -1687,10 +1773,11 @@ int
 Perl_magic_getsubstr(pTHX_ SV *sv, MAGIC *mg)
 {
     STRLEN len;
-    SV *lsv = LvTARG(sv);
-    char *tmps = SvPV(lsv,len);
+    SV * const lsv = LvTARG(sv);
+    const char * const tmps = SvPV(lsv,len);
     I32 offs = LvTARGOFF(sv);
     I32 rem = LvTARGLEN(sv);
+    (void)mg;
 
     if (SvUTF8(lsv))
 	sv_pos_u2b(lsv, &offs, &rem);
@@ -1709,24 +1796,30 @@ Perl_magic_setsubstr(pTHX_ SV *sv, MAGIC *mg)
 {
     STRLEN len;
     char *tmps = SvPV(sv, len);
-    SV *lsv = LvTARG(sv);
+    SV * const lsv = LvTARG(sv);
     I32 lvoff = LvTARGOFF(sv);
     I32 lvlen = LvTARGLEN(sv);
+    (void)mg;
 
     if (DO_UTF8(sv)) {
 	sv_utf8_upgrade(lsv);
  	sv_pos_u2b(lsv, &lvoff, &lvlen);
 	sv_insert(lsv, lvoff, lvlen, tmps, len);
+	LvTARGLEN(sv) = sv_len_utf8(sv);
 	SvUTF8_on(lsv);
     }
     else if (lsv && SvUTF8(lsv)) {
 	sv_pos_u2b(lsv, &lvoff, &lvlen);
+	LvTARGLEN(sv) = len;
 	tmps = (char*)bytes_to_utf8((U8*)tmps, &len);
 	sv_insert(lsv, lvoff, lvlen, tmps, len);
 	Safefree(tmps);
     }
-    else
-        sv_insert(lsv, lvoff, lvlen, tmps, len);
+    else {
+	sv_insert(lsv, lvoff, lvlen, tmps, len);
+	LvTARGLEN(sv) = len;
+    }
+
 
     return 0;
 }
@@ -1742,6 +1835,7 @@ Perl_magic_gettaint(pTHX_ SV *sv, MAGIC *mg)
 int
 Perl_magic_settaint(pTHX_ SV *sv, MAGIC *mg)
 {
+    (void)sv;
     if (PL_localizing) {
 	if (PL_localizing == 1)
 	    mg->mg_len <<= 1;
@@ -1758,10 +1852,11 @@ Perl_magic_settaint(pTHX_ SV *sv, MAGIC *mg)
 int
 Perl_magic_getvec(pTHX_ SV *sv, MAGIC *mg)
 {
-    SV *lsv = LvTARG(sv);
+    SV * const lsv = LvTARG(sv);
+    (void)mg;
 
     if (!lsv) {
-	(void)SvOK_off(sv);
+	SvOK_off(sv);
 	return 0;
     }
 
@@ -1772,6 +1867,7 @@ Perl_magic_getvec(pTHX_ SV *sv, MAGIC *mg)
 int
 Perl_magic_setvec(pTHX_ SV *sv, MAGIC *mg)
 {
+    (void)mg;
     do_vecset(sv);	/* XXX slurp this routine */
     return 0;
 }
@@ -1811,6 +1907,7 @@ Perl_magic_getdefelem(pTHX_ SV *sv, MAGIC *mg)
 int
 Perl_magic_setdefelem(pTHX_ SV *sv, MAGIC *mg)
 {
+    (void)mg;
     if (LvTARGLEN(sv))
 	vivify_defelem(sv);
     if (LvTARG(sv)) {
@@ -1862,18 +1959,21 @@ Perl_magic_killbackrefs(pTHX_ SV *sv, MAGIC *mg)
     AV *av = (AV*)mg->mg_obj;
     SV **svp = AvARRAY(av);
     I32 i = AvFILLp(av);
+    (void)sv;
+
     while (i >= 0) {
-	if (svp[i] && svp[i] != &PL_sv_undef) {
+	if (svp[i]) {
 	    if (!SvWEAKREF(svp[i]))
 		Perl_croak(aTHX_ "panic: magic_killbackrefs");
 	    /* XXX Should we check that it hasn't changed? */
-	    SvRV(svp[i]) = 0;
-	    (void)SvOK_off(svp[i]);
+	    SvRV_set(svp[i], 0);
+	    SvOK_off(svp[i]);
 	    SvWEAKREF_off(svp[i]);
-	    svp[i] = &PL_sv_undef;
+	    svp[i] = Nullsv;
 	}
 	i--;
     }
+    SvREFCNT_dec(av); /* remove extra count added by sv_add_backref() */
     return 0;
 }
 
@@ -1888,6 +1988,7 @@ Perl_magic_setmglob(pTHX_ SV *sv, MAGIC *mg)
 int
 Perl_magic_setbm(pTHX_ SV *sv, MAGIC *mg)
 {
+    (void)mg;
     sv_unmagic(sv, PERL_MAGIC_bm);
     SvVALID_off(sv);
     return 0;
@@ -1896,6 +1997,7 @@ Perl_magic_setbm(pTHX_ SV *sv, MAGIC *mg)
 int
 Perl_magic_setfm(pTHX_ SV *sv, MAGIC *mg)
 {
+    (void)mg;
     sv_unmagic(sv, PERL_MAGIC_fm);
     SvCOMPILED_off(sv);
     return 0;
@@ -1904,7 +2006,7 @@ Perl_magic_setfm(pTHX_ SV *sv, MAGIC *mg)
 int
 Perl_magic_setuvar(pTHX_ SV *sv, MAGIC *mg)
 {
-    struct ufuncs *uf = (struct ufuncs *)mg->mg_ptr;
+    const struct ufuncs * const uf = (struct ufuncs *)mg->mg_ptr;
 
     if (uf && uf->uf_set)
 	(*uf->uf_set)(aTHX_ uf->uf_index, sv);
@@ -1914,6 +2016,7 @@ Perl_magic_setuvar(pTHX_ SV *sv, MAGIC *mg)
 int
 Perl_magic_setregexp(pTHX_ SV *sv, MAGIC *mg)
 {
+    (void)mg;
     sv_unmagic(sv, PERL_MAGIC_qr);
     return 0;
 }
@@ -1923,6 +2026,7 @@ Perl_magic_freeregexp(pTHX_ SV *sv, MAGIC *mg)
 {
     regexp *re = (regexp *)mg->mg_obj;
     ReREFCNT_dec(re);
+    (void)sv;
     return 0;
 }
 
@@ -1934,6 +2038,7 @@ Perl_magic_setcollxfrm(pTHX_ SV *sv, MAGIC *mg)
      * RenE<eacute> Descartes said "I think not."
      * and vanished with a faint plop.
      */
+    (void)sv;
     if (mg->mg_ptr) {
 	Safefree(mg->mg_ptr);
 	mg->mg_ptr = NULL;
@@ -1947,6 +2052,7 @@ Perl_magic_setcollxfrm(pTHX_ SV *sv, MAGIC *mg)
 int
 Perl_magic_setutf8(pTHX_ SV *sv, MAGIC *mg)
 {
+    (void)sv;
     Safefree(mg->mg_ptr);	/* The mg_ptr holds the pos cache. */
     mg->mg_ptr = 0;
     mg->mg_len = -1;		/* The mg_len holds the len cache. */
@@ -1956,7 +2062,7 @@ Perl_magic_setutf8(pTHX_ SV *sv, MAGIC *mg)
 int
 Perl_magic_set(pTHX_ SV *sv, MAGIC *mg)
 {
-    register char *s;
+    register const char *s;
     I32 i;
     STRLEN len;
     switch (*mg->mg_ptr) {
@@ -1968,8 +2074,13 @@ Perl_magic_set(pTHX_ SV *sv, MAGIC *mg)
 	break;
 
     case '\004':	/* ^D */
-	PL_debug = (SvIOK(sv) ? SvIVX(sv) : sv_2iv(sv)) | DEBUG_TOP_FLAG;
+#ifdef DEBUGGING
+	s = SvPV_nolen(sv);
+	PL_debug = get_debug_opts(&s, 0) | DEBUG_TOP_FLAG;
 	DEBUG_x(dump_all());
+#else
+	PL_debug = (SvIOK(sv) ? SvIVX(sv) : sv_2iv(sv)) | DEBUG_TOP_FLAG;
+#endif
 	break;
     case '\005':  /* ^E */
 	if (*(mg->mg_ptr+1) == '\0') {
@@ -2013,18 +2124,20 @@ Perl_magic_set(pTHX_ SV *sv, MAGIC *mg)
 	if (PL_inplace)
 	    Safefree(PL_inplace);
 	if (SvOK(sv))
-	    PL_inplace = savepv(SvPV(sv,len));
+	    PL_inplace = savesvpv(sv);
 	else
 	    PL_inplace = Nullch;
 	break;
     case '\017':	/* ^O */
 	if (*(mg->mg_ptr+1) == '\0') {
-	    if (PL_osname)
+	    if (PL_osname) {
 		Safefree(PL_osname);
-	    if (SvOK(sv))
-		PL_osname = savepv(SvPV(sv,len));
-	    else
 		PL_osname = Nullch;
+	    }
+	    if (SvOK(sv)) {
+		TAINT_PROPER("assigning to $^O");
+		PL_osname = savesvpv(sv);
+	    }
 	}
 	else if (strEQ(mg->mg_ptr, "\017PEN")) {
 	    if (!PL_compiling.cop_io)
@@ -2064,7 +2177,7 @@ Perl_magic_set(pTHX_ SV *sv, MAGIC *mg)
 		    STRLEN len, i;
 		    int accumulate = 0 ;
 		    int any_fatals = 0 ;
-		    char * ptr = (char*)SvPV(sv, len) ;
+		    const char * const ptr = (char*)SvPV(sv, len) ;
 		    for (i = 0 ; i < len ; ++i) {
 		        accumulate |= ptr[i] ;
 		        any_fatals |= (ptr[i] & 0xAA) ;
@@ -2098,13 +2211,13 @@ Perl_magic_set(pTHX_ SV *sv, MAGIC *mg)
 	break;
     case '^':
 	Safefree(IoTOP_NAME(GvIOp(PL_defoutgv)));
-	IoTOP_NAME(GvIOp(PL_defoutgv)) = s = savepv(SvPV(sv,len));
-	IoTOP_GV(GvIOp(PL_defoutgv)) = gv_fetchpv(s,TRUE, SVt_PVIO);
+	s = IoTOP_NAME(GvIOp(PL_defoutgv)) = savesvpv(sv);
+	IoTOP_GV(GvIOp(PL_defoutgv)) = gv_fetchsv(sv,TRUE, SVt_PVIO);
 	break;
     case '~':
 	Safefree(IoFMT_NAME(GvIOp(PL_defoutgv)));
-	IoFMT_NAME(GvIOp(PL_defoutgv)) = s = savepv(SvPV(sv,len));
-	IoFMT_GV(GvIOp(PL_defoutgv)) = gv_fetchpv(s,TRUE, SVt_PVIO);
+	s = IoFMT_NAME(GvIOp(PL_defoutgv)) = savesvpv(sv);
+	IoFMT_GV(GvIOp(PL_defoutgv)) = gv_fetchsv(sv,TRUE, SVt_PVIO);
 	break;
     case '=':
 	IoPAGE_LEN(GvIOp(PL_defoutgv)) = (SvIOK(sv) ? SvIVX(sv) : sv_2iv(sv));
@@ -2134,10 +2247,6 @@ Perl_magic_set(pTHX_ SV *sv, MAGIC *mg)
 	    }
 	}
 	break;
-    case '*':
-	i = SvIOK(sv) ? SvIVX(sv) : sv_2iv(sv);
-	PL_multiline = (i != 0);
-	break;
     case '/':
 	SvREFCNT_dec(PL_rs);
 	PL_rs = newSVsv(sv);
@@ -2165,7 +2274,7 @@ Perl_magic_set(pTHX_ SV *sv, MAGIC *mg)
     case '#':
 	if (PL_ofmt)
 	    Safefree(PL_ofmt);
-	PL_ofmt = savepv(SvPV(sv,len));
+	PL_ofmt = savesvpv(sv);
 	break;
     case '[':
 	PL_compiling.cop_arybase = SvIOK(sv) ? SvIVX(sv) : sv_2iv(sv);
@@ -2211,9 +2320,14 @@ Perl_magic_set(pTHX_ SV *sv, MAGIC *mg)
 #ifdef HAS_SETRESUID
       (void)setresuid((Uid_t)PL_uid, (Uid_t)-1, (Uid_t)-1);
 #else
-	if (PL_uid == PL_euid)		/* special case $< = $> */
+	if (PL_uid == PL_euid) {		/* special case $< = $> */
+#ifdef PERL_DARWIN
+	    /* workaround for Darwin's setuid peculiarity, cf [perl #24122] */
+	    if (PL_uid != 0 && PerlProc_getuid() == 0)
+		(void)PerlProc_setuid(0);
+#endif
 	    (void)PerlProc_setuid(PL_uid);
-	else {
+	} else {
 	    PL_uid = PerlProc_getuid();
 	    Perl_croak(aTHX_ "setruid() not implemented");
 	}
@@ -2280,7 +2394,7 @@ Perl_magic_set(pTHX_ SV *sv, MAGIC *mg)
     case ')':
 #ifdef HAS_SETGROUPS
 	{
-	    char *p = SvPV(sv, len);
+	    const char *p = SvPV(sv, len);
 	    Groups_t gary[NGROUPS];
 
 	    while (isSPACE(*p))
@@ -2360,65 +2474,32 @@ Perl_magic_set(pTHX_ SV *sv, MAGIC *mg)
 	{
 	     union pstun un;
 	     s = SvPV(sv, len);
-	     un.pst_command = s;
+	     un.pst_command = (char *)s;
 	     pstat(PSTAT_SETCMD, un, len, 0, 0);
 	}
 #endif
-	if (!PL_origalen) {
-	    s = PL_origargv[0];
-	    s += strlen(s);
-	    /* See if all the arguments are contiguous in memory */
-	    for (i = 1; i < PL_origargc; i++) {
-		if (PL_origargv[i] == s + 1
-#ifdef OS2
-		    || PL_origargv[i] == s + 2
-#endif
-		   )
-		{
-		    ++s;
-		    s += strlen(s);	/* this one is ok too */
-		}
-		else
-		    break;
-	    }
-	    /* can grab env area too? */
-	    if (PL_origenviron
-#ifdef USE_ITHREADS
-		&& PL_curinterp == aTHX
-#endif
-		&& (PL_origenviron[0] == s + 1))
-	    {
-		my_setenv("NoNe  SuCh", Nullch);
-					    /* force copy of environment */
-		for (i = 0; PL_origenviron[i]; i++)
-		    if (PL_origenviron[i] == s + 1) {
-			++s;
-			s += strlen(s);
-		    }
-		    else
-			break;
-	    }
-	    PL_origalen = s - PL_origargv[0];
-	}
+	/* PL_origalen is set in perl_parse(). */
 	s = SvPV_force(sv,len);
-	i = len;
-	if (i >= (I32)PL_origalen) {
-	    i = PL_origalen;
-	    /* don't allow system to limit $0 seen by script */
-	    /* SvCUR_set(sv, i); *SvEND(sv) = '\0'; */
-	    Copy(s, PL_origargv[0], i, char);
-	    s = PL_origargv[0]+i;
-	    *s = '\0';
+	if (len >= (STRLEN)PL_origalen-1) {
+	    /* Longer than original, will be truncated. We assume that
+             * PL_origalen bytes are available. */
+	    Copy(s, PL_origargv[0], PL_origalen-1, char);
 	}
 	else {
-	    Copy(s, PL_origargv[0], i, char);
-	    s = PL_origargv[0]+i;
-	    *s++ = '\0';
-	    while (++i < (I32)PL_origalen)
-		*s++ = '\0';
-	    for (i = 1; i < PL_origargc; i++)
-		PL_origargv[i] = Nullch;
-	}
+	    /* Shorter than original, will be padded. */
+	    Copy(s, PL_origargv[0], len, char);
+	    PL_origargv[0][len] = 0;
+	    memset(PL_origargv[0] + len + 1,
+		   /* Is the space counterintuitive?  Yes.
+		    * (You were expecting \0?)  
+		    * Does it work?  Seems to.  (In Linux 2.4.20 at least.)
+		    * --jhi */
+		   (int)' ',
+		   PL_origalen - len - 1);
+	}
+	PL_origargv[0][PL_origalen-1] = 0;
+	for (i = 1; i < PL_origargc; i++)
+	    PL_origargv[i] = 0;
 	UNLOCK_DOLLARZERO_MUTEX;
 	break;
 #endif
@@ -2427,13 +2508,13 @@ Perl_magic_set(pTHX_ SV *sv, MAGIC *mg)
 }
 
 I32
-Perl_whichsig(pTHX_ char *sig)
+Perl_whichsig(pTHX_ const char *sig)
 {
-    register char **sigv;
+    register char* const* sigv;
 
-    for (sigv = PL_sig_name+1; *sigv; sigv++)
+    for (sigv = (char* const*)PL_sig_name; *sigv; sigv++)
 	if (strEQ(sig,*sigv))
-	    return PL_sig_num[sigv - PL_sig_name];
+	    return PL_sig_num[sigv - (char* const*)PL_sig_name];
 #ifdef SIGCLD
     if (strEQ(sig,"CHLD"))
 	return SIGCLD;
@@ -2442,13 +2523,9 @@ Perl_whichsig(pTHX_ char *sig)
     if (strEQ(sig,"CLD"))
 	return SIGCHLD;
 #endif
-    return 0;
+    return -1;
 }
 
-#if !defined(PERL_IMPLICIT_CONTEXT)
-static SV* sig_sv;
-#endif
-
 Signal_t
 Perl_sighandler(int sig)
 {
@@ -2470,8 +2547,6 @@ Perl_sighandler(int sig)
 	flags |= 1;
     if (PL_markstack_ptr < PL_markstack_max - 2)
 	flags |= 4;
-    if (PL_retstack_ix < PL_retstack_max - 2)
-	flags |= 8;
     if (PL_scopestack_ix < PL_scopestack_max - 3)
 	flags |= 16;
 
@@ -2489,10 +2564,6 @@ Perl_sighandler(int sig)
     }
     if (flags & 4)
 	PL_markstack_ptr++;		/* Protect mark. */
-    if (flags & 8) {
-	PL_retstack_ix++;
-	PL_retstack[PL_retstack_ix] = NULL;
-    }
     if (flags & 16)
 	PL_scopestack_ix += 1;
     /* sv_2cv is too complicated, try a simpler variant first: */
@@ -2514,7 +2585,7 @@ Perl_sighandler(int sig)
     	sv = SvREFCNT_inc(PL_psig_name[sig]);
 	flags |= 64;
 #if !defined(PERL_IMPLICIT_CONTEXT)
-	sig_sv = sv;
+	PL_sig_sv = sv;
 #endif
     } else {
 	sv = sv_newmortal();
@@ -2543,18 +2614,16 @@ Perl_sighandler(int sig)
 #else
 	/* Not clear if this will work */
 	(void)rsignal(sig, SIG_IGN);
-	(void)rsignal(sig, &Perl_csighandler);
+	(void)rsignal(sig, PL_csighandlerp);
 #endif
 #endif /* !PERL_MICRO */
-	Perl_die(aTHX_ Nullformat);
+	DieNull;
     }
 cleanup:
     if (flags & 1)
 	PL_savestack_ix -= 8; /* Unprotect save in progress. */
     if (flags & 4)
 	PL_markstack_ptr--;
-    if (flags & 8)
-	PL_retstack_ix--;
     if (flags & 16)
 	PL_scopestack_ix -= 1;
     if (flags & 64)
@@ -2568,7 +2637,7 @@ cleanup:
 
 
 static void
-restore_magic(pTHX_ void *p)
+restore_magic(pTHX_ const void *p)
 {
     MGS* mgs = SSPTR(PTR2IV(p), MGS*);
     SV* sv = mgs->mgs_sv;
@@ -2578,6 +2647,13 @@ restore_magic(pTHX_ void *p)
 
     if (SvTYPE(sv) >= SVt_PVMG && SvMAGIC(sv))
     {
+#ifdef PERL_COPY_ON_WRITE
+	/* While magic was saved (and off) sv_setsv may well have seen
+	   this SV as a prime candidate for COW.  */
+	if (SvIsCOW(sv))
+	    sv_force_normal(sv);
+#endif
+
 	if (mgs->mgs_flags)
 	    SvFLAGS(sv) |= mgs->mgs_flags;
 	else
@@ -2609,16 +2685,17 @@ restore_magic(pTHX_ void *p)
 }
 
 static void
-unwind_handler_stack(pTHX_ void *p)
+unwind_handler_stack(pTHX_ const void *p)
 {
-    U32 flags = *(U32*)p;
+    dVAR;
+    const U32 flags = *(const U32*)p;
 
     if (flags & 1)
 	PL_savestack_ix -= 5; /* Unprotect save in progress. */
     /* cxstack_ix-- Not needed, die already unwound it. */
 #if !defined(PERL_IMPLICIT_CONTEXT)
     if (flags & 64)
-	SvREFCNT_dec(sig_sv);
+	SvREFCNT_dec(PL_sig_sv);
 #endif
 }