Subject: Re: emacs: paxctl usage on NetBSD

From: Thomas Klausner <[email-masked]>
Date: Wed, 27 Apr 2016 17:54:42 +0200

Hi Paul!

Thanks for the fast reply!

On Mon, Apr 25, 2016 at 05:09:56PM -0700, Paul Eggert wrote:
> >When I replace 'paxctl -zex' with 'paxctl +a' in src/Makefile.in, the
> >build succeeds.
> 
> Did you do something other than just that replacement?

No.

> configure.ac says
> that paxctl is used only when the operating system is GNU/Linux, unless one
> manually configures by setting PAXCTL in the environment or using a
> PAXCTL=/some/path argument to 'configure'.

That's true, but src/Makefile.in ignores that:
PAXCTL_if_present = $(or $(PAXCTL),: paxctl)

> Does the attached patch to the emacs-25 branch work for you?

I've modified it to apply to git head but it didn't work:

Finding pointers to doc strings...
Finding pointers to doc strings...done
Loading /scratch/wip/emacs-current/work/emacs/lisp/site-init.el (source)...
Dumping under the name emacs
18932704 of 33554432 static heap bytes used
91843 pure bytes used
/usr/sbin/paxctl +a emacs
mv -f emacs bootstrap-emacs
/usr/sbin/paxctl +a bootstrap-emacs
/usr/pkg/bin/gmake -C ../lisp compile-first EMACS="../src/bootstrap-emacs"
gmake[3]: Entering directory '/scratch/wip/emacs-current/work/emacs/lisp'
  ELC      emacs-lisp/macroexp.elc
Memory fault (core dumped)
Makefile:282: recipe for target 'emacs-lisp/macroexp.elc' failed

My version is attached (I added some more paxctl's for the symlinks
when the original version didn't work.) I hope I didn't break it.

 Thomas

$NetBSD$

Problem reported by Thomas Klausner (Bug#23371).
* configure.ac (PAXCTL_dumped, PAXCTL_notdumped): New vars.
Set them to setfattr and/or paxctl commands appropriate for
GNU/Linux and/or NetBSD; the latter prefers paxctl +a.  Search
for paxctl only if setfattr is not found.
* src/Makefile.in (PAXCTL_dumped, PAXCTL_notdumped):
New vars, replacing PAXCTL_if_present and SETFATTR_if_present.
All uses changed.

--- configure.ac.orig	2016-04-22 16:23:52.000000000 +0000
+++ configure.ac
@@ -1159,16 +1159,9 @@ AC_PATH_PROG(GZIP_PROG, gzip)
 test $with_compress_install != yes && test -n "$GZIP_PROG" && \
    GZIP_PROG=" # $GZIP_PROG # (disabled by configure --without-compress-install)"
 
+PAXCTL_dumped=
+PAXCTL_notdumped=
 if test $opsys = gnu-linux; then
-  AC_PATH_PROG(PAXCTL, paxctl,,
-    [$PATH$PATH_SEPARATOR/sbin$PATH_SEPARATOR/usr/sbin])
-  if test "X$PAXCTL" != X; then
-    AC_MSG_CHECKING([whether binaries have a PT_PAX_FLAGS header])
-    AC_LINK_IFELSE([AC_LANG_PROGRAM([], [])],
-      [if $PAXCTL -v conftest$EXEEXT >/dev/null 2>&1; then AC_MSG_RESULT(yes)
-      else AC_MSG_RESULT(no); PAXCTL=""; fi])
-  fi
-
   if test "${SETFATTR+set}" != set; then
     AC_CACHE_CHECK([for setfattr],
       [emacs_cv_prog_setfattr],
@@ -1179,6 +1172,7 @@ if test $opsys = gnu-linux; then
 	 emacs_cv_prog_setfattr=no
        fi])
     if test "$emacs_cv_prog_setfattr" = yes; then
+      PAXCTL_notdumped='$(SETFATTR) -n user.pax.flags -v er'
       SETFATTR=setfattr
     else
       SETFATTR=
@@ -1187,6 +1181,31 @@ if test $opsys = gnu-linux; then
     AC_SUBST([SETFATTR])
   fi
 fi
+case $opsys,$PAXCTL_notdumped in
+  gnu-linux, | netbsd,)
+    AC_PATH_PROG([PAXCTL], [paxctl], [],
+      [$PATH$PATH_SEPARATOR/sbin$PATH_SEPARATOR/usr/sbin])
+    if test -n "$PAXCTL"; then
+      if test "$opsys" = netbsd; then
+	PAXCTL_dumped='$(PAXCTL) +a'
+      else
+	AC_MSG_CHECKING([whether binaries have a PT_PAX_FLAGS header])
+	AC_LINK_IFELSE([AC_LANG_PROGRAM([], [])],
+	  [if $PAXCTL -v conftest$EXEEXT >/dev/null 2>&1; then
+	     AC_MSG_RESULT([yes])
+	   else
+	     AC_MSG_RESULT([no])
+	     PAXCTL=
+	   fi])
+	if test -n "$PAXCTL"; then
+	  PAXCTL_dumped='$(PAXCTL) -zex'
+	  PAXCTL_notdumped='$(PAXCTL) -r'
+	fi
+      fi
+    fi;;
+esac
+AC_SUBST([PAXCTL_dumped])
+AC_SUBST([PAXCTL_notdumped])
 
 ## Need makeinfo >= 4.7 (?) to build the manuals.
 if test "$MAKEINFO" != "no"; then
$NetBSD$

Problem reported by Thomas Klausner (Bug#23371).
* configure.ac (PAXCTL_dumped, PAXCTL_notdumped): New vars.
Set them to setfattr and/or paxctl commands appropriate for
GNU/Linux and/or NetBSD; the latter prefers paxctl +a.  Search
for paxctl only if setfattr is not found.
* src/Makefile.in (PAXCTL_dumped, PAXCTL_notdumped):
New vars, replacing PAXCTL_if_present and SETFATTR_if_present.
All uses changed.

--- src/Makefile.in.orig	2016-04-17 20:51:40.000000000 +0000
+++ src/Makefile.in
@@ -114,8 +114,9 @@ TEMACS_LDFLAGS = $(LD_SWITCH_SYSTEM) $(L
 ## around this, newer ones setfattr.  See Bug#11398 and Bug#16343.
 PAXCTL = @PAXCTL@
 SETFATTR = @SETFATTR@
-PAXCTL_if_present = $(or $(PAXCTL),: paxctl)
-SETFATTR_if_present = $(or $(SETFATTR),: setfattr)
+## Commands to set PaX flags on dumped and not-dumped instances of Emacs.
+PAXCTL_dumped = @PAXCTL_dumped@
+PAXCTL_notdumped = @PAXCTL_notdumped@
 
 ## Some systems define this to request special libraries.
 LIBS_SYSTEM=@LIBS_SYSTEM@
@@ -542,8 +543,13 @@ ifeq ($(CANNOT_DUMP),yes)
 	ln -f temacs$(EXEEXT) $@
 else
 	LC_ALL=C $(RUN_TEMACS) -batch $(BUILD_DETAILS) -l loadup dump
-	$(PAXCTL_if_present) -zex $@
+ifneq ($(PAXCTL_dumped),)
+	$(PAXCTL_dumped) $@
+endif
 	ln -f $@ bootstrap-emacs$(EXEEXT)
+ifneq ($(PAXCTL_dumped),)
+	$(PAXCTL_dumped) bootstrap-emacs$(EXEEXT)
+endif
 endif
 
 ## We run make-docfile twice because the command line may get too long
@@ -606,8 +612,9 @@ temacs$(EXEEXT): $(LIBXMENU) $(ALLOBJS) 
 	  -o temacs $(ALLOBJS) $(LIBEGNU_ARCHIVE) $(W32_RES_LINK) $(LIBES)
 	$(MKDIR_P) $(etc)
 ifneq ($(CANNOT_DUMP),yes)
-	$(PAXCTL_if_present) -r $@
-	$(SETFATTR_if_present) -n user.pax.flags -v er $@
+  ifneq ($(PAXCTL_notdumped),)
+	$(PAXCTL_notdumped) $@
+  endif
 endif
 
 ## The following oldxmenu-related rules are only (possibly) used if
@@ -748,8 +755,13 @@ ifeq ($(CANNOT_DUMP),yes)
 	ln -f temacs$(EXEEXT) $@
 else
 	$(RUN_TEMACS) --batch $(BUILD_DETAILS) --load loadup bootstrap
-	$(PAXCTL_if_present) -zex emacs$(EXEEXT)
+ifneq ($(PAXCTL_dumped),)
+	$(PAXCTL_dumped) emacs$(EXEEXT)
+endif
 	mv -f emacs$(EXEEXT) $@
+ifneq ($(PAXCTL_dumped),)
+	$(PAXCTL_dumped) $@
+endif
 endif
 	@: Compile some files earlier to speed up further compilation.
 	$(MAKE) -C ../lisp compile-first EMACS="$(bootstrap_exe)"