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[perl #116407] SvPVutf8 != SvPVX, and sv_2pvutf8
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From:
bulk88
Date:
January 15, 2013 21:24
Subject:
[perl #116407] SvPVutf8 != SvPVX, and sv_2pvutf8
Message ID:
rt-3.6.HEAD-4370-1358285068-771.116407-75-0@perl.org
# New Ticket Created by bulk88
# Please include the string: [perl #116407]
# in the subject line of all future correspondence about this issue.
# <URL: https://rt.perl.org:443/rt3/Ticket/Display.html?id=116407 >
This is a bug report for perl from bulk88@hotmail.com,
generated with the help of perlbug 1.39 running under perl 5.17.7.
-----------------------------------------------------------------
[Please describe your issue here]
I recently found a bug in a core module, where a loop was done over a
string from SvPVutf8(sv, len) to SvEND(sv). The sv is a RO literal SV.
So it looped over uninitialized memory and sometimes segvs.
http://perl5.git.perl.org/perl.git/blob/a8c6ff7b8e8c6037333c21f9b3f6b38b9278df4f:/sv.c#l3060
A mortal copy was made of the RO SV was made and returned as the result
of SvPVutf8.
All that SvPVutf8's docs say is "Like C<SvPV>, but converts sv to utf8
first if necessary."
SvPV says "The SV may cache the stringified version becoming C<SvPOK>."
So that is the disclaimer that SvPVX after SvPV is not the same pointer
as returned from SvPV. I think the docs can be improved for SvPVutf8 and
maybe SvPV to make it more obvious that these 2 do not create POK SVs. I
don't have any proposed wording so no patch is included.
This ticket might be related to
http://perl5.git.perl.org/perl.git/commit/fe46cbda823c09f80e4bc48dd93fafb26cc805f6
and https://rt.perl.org/rt3/Ticket/Display.html?id=108994 .
[Please do not change anything below this line]
-----------------------------------------------------------------
---
Flags:
category=core
severity=medium
---
Site configuration information for perl 5.17.7:
Configured by Owner at Sun Dec 16 13:25:34 2012.
Summary of my perl5 (revision 5 version 17 subversion 7 patch blead
2012-12-06.16:42:20 93a641ae382638ffd1980378be4810244d04f4b0
v5.17.6-186-g93a641a) configuration:
Snapshot of: 93a641ae382638ffd1980378be4810244d04f4b0
Platform:
osname=MSWin32, osvers=5.1, archname=MSWin32-x86-multi-thread
uname=''
config_args='undef'
hint=recommended, useposix=true, d_sigaction=undef
useithreads=define, usemultiplicity=define
useperlio=define, d_sfio=undef, uselargefiles=define, usesocks=undef
use64bitint=undef, use64bitall=undef, uselongdouble=undef
usemymalloc=n, bincompat5005=undef
Compiler:
cc='cl', ccflags ='-nologo -GF -W3 -MD -Zi -DNDEBUG -O1 -GL -G7
-DWIN32 -D_CONSOLE -DNO_STRICT -DPERL_TEXTMODE_SCRIPTS
-DPERL_IMPLICIT_CONTEXT -DPERL_IMPLICIT_SYS -DUSE_PERLIO
-D_USE_32BIT_TIME_T',
optimize='-MD -Zi -DNDEBUG -O1 -GL -G7',
cppflags='-DWIN32'
ccversion='13.10.6030', gccversion='', gccosandvers=''
intsize=4, longsize=4, ptrsize=4, doublesize=8, byteorder=1234
d_longlong=undef, longlongsize=8, d_longdbl=define, longdblsize=8
ivtype='long', ivsize=4, nvtype='double', nvsize=8, Off_t='__int64',
lseeksize=8
alignbytes=8, prototype=define
Linker and Libraries:
ld='link', ldflags ='-nologo -nodefaultlib -debug -opt:ref,icf
-ltcg -libpath:"c:\perl517\lib\CORE" -machine:x86'
libpth="C:\Program Files\Microsoft Visual Studio .NET 2003\VC7\lib"
libs=oldnames.lib kernel32.lib user32.lib gdi32.lib winspool.lib
comdlg32.lib advapi32.lib shell32.lib ole32.lib oleaut32.lib
netapi32.lib uuid.lib ws2_32.lib mpr.lib winmm.lib version.lib
odbc32.lib odbccp32.lib comctl32.lib msvcrt.lib
perllibs=oldnames.lib kernel32.lib user32.lib gdi32.lib
winspool.lib comdlg32.lib advapi32.lib shell32.lib ole32.lib
oleaut32.lib netapi32.lib uuid.lib ws2_32.lib mpr.lib winmm.lib
version.lib odbc32.lib odbccp32.lib comctl32.lib msvcrt.lib
libc=msvcrt.lib, so=dll, useshrplib=true, libperl=perl517.lib
gnulibc_version=''
Dynamic Linking:
dlsrc=dl_win32.xs, dlext=dll, d_dlsymun=undef, ccdlflags=' '
cccdlflags=' ', lddlflags='-dll -nologo -nodefaultlib -debug
-opt:ref,icf -ltcg -libpath:"c:\perl517\lib\CORE" -machine:x86'
Locally applied patches:
---
@INC for perl 5.17.7:
C:/perl517/site/lib
C:/perl517/lib
.
---
Environment for perl 5.17.7:
HOME (unset)
LANG (unset)
LANGUAGE (unset)
LD_LIBRARY_PATH (unset)
LOGDIR (unset)
PATH=C:\perl517\bin;C:\Program Files\Microsoft Visual Studio .NET
2003\Common7\IDE;C:\Program Files\Microsoft Visual Studio .NET
2003\VC7\BIN;C:\Program Files\Microsoft Visual Studio .NET
2003\Common7\Tools;C:\Program Files\Microsoft Visual Studio .NET
2003\Common7\Tools\bin\prerelease;C:\WINDOWS\system32;C:\WINDOWS;C:\WINDOWS\system32\wbem;
PERL_BADLANG (unset)
SHELL (unset)
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[perl #116407] SvPVutf8 != SvPVX, and sv_2pvutf8
by bulk88