/* mg.c
*
* Copyright (C) 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999,
- * 2000, 2001, 2002, 2003, by Larry Wall and others
+ * 2000, 2001, 2002, 2003, 2004, 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.
/*
=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"
int new = 0;
MAGIC *newmg, *head, *cur, *mg;
I32 mgs_ix = SSNEW(sizeof(MGS));
+ int was_temp = SvTEMP(sv);
+ /* 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);
if (!(mg->mg_flags & MGf_GSKIP) && vtbl && vtbl->svt_get) {
CALL_FPTR(vtbl->svt_get)(aTHX_ sv, mg);
- /* guard against sv having been freed */
- if (SvTYPE(sv) == SVTYPEMASK) {
- Perl_croak(aTHX_ "Tied variable freed while still in use");
- }
/* guard against magic having been deleted - eg FETCH calling
* untie */
if (!SvMAGIC(sv))
}
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. */
+ (void)SvOK_off(sv);
+ }
return 0;
}
return 0;
}
-
-#if !defined(NSIG) || defined(M_UNIX) || defined(__unix) || defined(M_XENIX)
#include <signal.h>
-#endif
U32
Perl_magic_regdata_cnt(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 '+':
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') {
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);
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;
}
SV **svp = AvARRAY(av);
I32 i = AvFILLp(av);
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]);
SvWEAKREF_off(svp[i]);
- svp[i] = &PL_sv_undef;
+ svp[i] = Nullsv;
}
i--;
}
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 = savepv(SvPV(sv,len));
+ }
}
else if (strEQ(mg->mg_ptr, "\017PEN")) {
if (!PL_compiling.cop_io)
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;
}
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: */
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)