Improve retrieving a scalar value of a variable modified in a signal handler

perl-5.31.0-perl-134035-ensure-sv_gets-handles-a-signal-handler-.patch

@@ -0,0 +1,42 @@
+From 368ac47cccd4ffca6e83a26289c152a32c2ea385 Mon Sep 17 00:00:00 2001
+From: Tony Cook <tony@develop-help.com>
+Date: Wed, 17 Apr 2019 15:45:15 +1000
+Subject: [PATCH] (perl #134035) ensure sv_gets() handles a signal handler
+ modifying sv
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+At a very basic level at least.
+
+In the ticket cases, a signal handler is modifying (and reallocating
+PVX) the sv, while sv_gets() retained a pointer to the inside of the
+SV.
+
+This still has some problems, like if the signal handler ends up
+shortening SV, there may be old data left between the old position
+and the new position, but I think that's a case of user error.
+
+Signed-off-by: Petr Písař <ppisar@redhat.com>
+---
+ sv.c | 3 +++
+ 1 file changed, 3 insertions(+)
+
+diff --git a/sv.c b/sv.c
+index 8bc0af0c16..83de536ad7 100644
+--- a/sv.c
++++ b/sv.c
+@@ -8755,7 +8755,10 @@ Perl_sv_gets(pTHX_ SV *const sv, PerlIO *const fp, I32 append)
+ 
+             Note we have to deal with the char in 'i' if we are not at EOF
+         */
++        bpx = bp - (STDCHAR*)SvPVX_const(sv);
++        /* signals might be called here, possibly modifying sv */
+ 	i   = PerlIO_getc(fp);		/* get more characters */
++        bp = (STDCHAR*)SvPVX_const(sv) + bpx;
+ 
+ 	DEBUG_Pv(PerlIO_printf(Perl_debug_log,
+ 	   "Screamer: post: FILE * thinks ptr=%" UVuf ", cnt=%" IVdf ", base=%" UVuf "\n",
+-- 
+2.20.1
+

perl.spec

@@ -187,6 +187,10 @@ Patch27:        perl-5.31.0-perl-133913-limit-numeric-format-results-to-INT_MAX.
 # fixed after 5.31.0
 Patch28:        perl-5.31.0-perl-134072-allow-foo-bar-to-work-in-main.patch
 
+# Improve retrieving a scalar value of a variable modified in a signal
+# handler, RT#134035, fixed after 5.31.0
+Patch29:        perl-5.31.0-perl-134035-ensure-sv_gets-handles-a-signal-handler-.patch
+
 # Link XS modules to libperl.so with EU::CBuilder on Linux, bug #960048
 Patch200:       perl-5.16.3-Link-XS-modules-to-libperl.so-with-EU-CBuilder-on-Li.patch
 
@@ -2733,6 +2737,7 @@ Perl extension for Version Objects
 %patch26 -p1
 %patch27 -p1
 %patch28 -p1
+%patch29 -p1
 %patch200 -p1
 %patch201 -p1
 
@@ -2768,6 +2773,7 @@ perl -x patchlevel.h \
     'Fedora Patch26: Fix an erroneous assertion on OP_SCALAR (RT#134048)' \
     'Fedora Patch27: Prevent from wrapping a width in a numeric format string (RT#133913)' \
     'Fedora Patch28: Fix subroutine protypes to track reference aliases (RT#134072)' \
+    'Fedora Patch29: Improve retrieving a scalar value of a variable modified in a signal handler (RT#134035)' \
     'Fedora Patch200: Link XS modules to libperl.so with EU::CBuilder on Linux' \
     'Fedora Patch201: Link XS modules to libperl.so with EU::MM on Linux' \
     %{nil}
@@ -5025,6 +5031,8 @@ popd
 - Fix an erroneous assertion on OP_SCALAR (RT#134048)
 - Prevent from wrapping a width in a numeric format string (RT#133913)
 - Fix subroutine protypes to track reference aliases (RT#134072)
+- Improve retrieving a scalar value of a variable modified in a signal handler
+  (RT#134035)
 
 * Tue Jun 11 2019 Jitka Plesnikova <jplesnik@redhat.com> - 4:5.30.0-439
 - Define %%perl_vendor*, %%perl_archlib, %%perl_privlib, because in rpm