On 08/20/2013 08:39 AM, Guido Günther wrote:
by adding it to AM_LDFLAGS instead of every linking rule and by avoiding a forked grep. --- Daniel kind of nacked the AM_LDFLAGS part already but I think it's a reasonable cleanup. We should rather use AM_LDFLAGS everywhere which (we currently don't and which would be another cleanup). Or are there any reasons to not have a read only GOT?
Personally, I like the idea of using AM_LDFLAGS everywhere, but as Daniel and I have opposing opinions, we'll need a third person to speak up.
+++ b/m4/virt-linker-relro.m4 @@ -22,10 +22,10 @@ AC_DEFUN([LIBVIRT_LINKER_RELRO],[ AC_MSG_CHECKING([for how to force completely read-only GOT table])
RELRO_LDFLAGS= - `$LD --help 2>&1 | grep -- "-z relro" >/dev/null` && \ - RELRO_LDFLAGS="-Wl,-z -Wl,relro" - `$LD --help 2>&1 | grep -- "-z now" >/dev/null` && \ - RELRO_LDFLAGS="$RELRO_LDFLAGS -Wl,-z -Wl,now" + case `$LD --help 2>&1` in + *"-z relro"*) RELRO_LDFLAGS="-Wl,-z -Wl,relro" ;&
';&' is a bashism; it is not portable to configure scripts
+ *"-z now"*) RELRO_LDFLAGS="$RELRO_LDFLAGS -Wl,-z -Wl,now" ;; + esac
Instead, this needs to be: ld_help=`$LD --help 2>&1` case $ld_help in *"-z relro"*) RELRO_LDFLAGS="-Wl,-z -Wl,relro" ;; esac case $ld_help in *"-z now"*) RELRO_LDFLAGS="$RELRO_LDFLAGS -Wl,-z -Wl,now" ;; esac
@@ -1812,7 +1814,6 @@ libvirt_la_LDFLAGS = \ -version-info $(LIBVIRT_VERSION_INFO) \ $(LIBVIRT_NODELETE) \ $(AM_LDFLAGS) \ - $(RELRO_LDFLAGS) \ $(CYGWIN_EXTRA_LDFLAGS) \ $(MINGW_EXTRA_LDFLAGS) \ $(NULL)
Hmm - maybe I see why Daniel expressed his opinion for not using $(AM_LDFLAGS) - notice that libraries to NOT use $(PIE_LDFLAGS)...
@@ -1964,7 +1963,6 @@ virtlockd_CFLAGS = \ virtlockd_LDFLAGS = \ $(AM_LDFLAGS) \ $(PIE_LDFLAGS) \ - $(RELRO_LDFLAGS) \ $(CYGWIN_EXTRA_LDFLAGS) \ $(MINGW_EXTRA_LDFLAGS) \ $(NULL)
...but executables do. But even then, maybe we want: LIBRARY_LDFLAGS = $(AM_LDFLAGS) EXEC_LDFLAGS = $(AM_LDFLAGS) $(PIE_LDFLAGS) then use the appropriate $({LIBRARY,EXEC}_LDFLAGS) in each place, rather than having lots of duplicate $(PIE_LDFLAGS)? -- Eric Blake eblake redhat com +1-919-301-3266 Libvirt virtualization library http://libvirt.org