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Re: glibc 2.24 -- Release blockers
On 07/20/2016 09:03 AM, Sinny Kumari wrote:
Applied this patch and emacs builds fine for Fedora rawhide [1] and
Fedora 24 [2] for
ppc64(le) arches.
Thanks for checking. I have one more thing to ask. As can be seen in
<http:// bugs.gnu.org/24033>, an Emacs maintainer had some qualms about
the size of the emacs-25 patch I sent you earlier, so I came up with the
attached, more-conservative patch instead. Can you please try the
revised patch on your ppc64 platform with draft glibc 2.24? If it works
for you, I have the OK to install this patch into the emacs-25 branch,
and I hope this resolves the pressing compatibility issues between draft
glibc 2.24 and Emacs.
>From 37bc57cf803f2ab0b7a7844730ebc17eb43e942d Mon Sep 17 00:00:00 2001
From: Paul Eggert <eggert@cs.ucla.edu>
Date: Tue, 19 Jul 2016 15:23:14 +0200
Subject: [PATCH] Port to glibc 2.24 (pre-release) + ppc64
Backport from master (Bug#24033).
Inspired by a suggestion by Florian Weimer in:
https://sourceware.org/ml/libc-alpha/2016-07/msg00425.html
* src/emacs.c (main) [__PPC64__]:
Special case for __PPC64__, which needs ASLR disabled in
dumped Emacs too.
---
src/emacs.c | 24 ++++++++++++++++++++++--
1 file changed, 22 insertions(+), 2 deletions(-)
diff --git a/src/emacs.c b/src/emacs.c
index 5c187e7..2480dfc 100644
--- a/src/emacs.c
+++ b/src/emacs.c
@@ -674,6 +674,26 @@ main (int argc, char **argv)
stack_base = &dummy;
+#if defined HAVE_PERSONALITY_LINUX32 && defined __PPC64__
+ /* This code partly duplicates the HAVE_PERSONALITY_LINUX32 code
+ below. This duplication is planned to be fixed in a later
+ Emacs release. */
+# define ADD_NO_RANDOMIZE 0x0040000
+ int pers = personality (0xffffffff);
+ if (! (pers & ADD_NO_RANDOMIZE)
+ && 0 <= personality (pers | ADD_NO_RANDOMIZE))
+ {
+ /* Address randomization was enabled, but is now disabled.
+ Re-execute Emacs to get a clean slate. */
+ execvp (argv[0], argv);
+
+ /* If the exec fails, warn the user and then try without a
+ clean slate. */
+ perror (argv[0]);
+ }
+# undef ADD_NO_RANDOMIZE
+#endif
+
#ifndef CANNOT_DUMP
might_dump = !initialized;
#endif
@@ -784,7 +804,7 @@ main (int argc, char **argv)
dumping = !initialized && (strcmp (argv[argc - 1], "dump") == 0
|| strcmp (argv[argc - 1], "bootstrap") == 0);
-#ifdef HAVE_PERSONALITY_LINUX32
+#if defined HAVE_PERSONALITY_LINUX32 && !defined __PPC64__
if (dumping && ! getenv ("EMACS_HEAP_EXEC"))
{
/* Set this so we only do this once. */
@@ -801,7 +821,7 @@ main (int argc, char **argv)
/* If the exec fails, try to dump anyway. */
emacs_perror (argv[0]);
}
-#endif /* HAVE_PERSONALITY_LINUX32 */
+#endif
#if defined (HAVE_SETRLIMIT) && defined (RLIMIT_STACK) && !defined (CYGWIN)
/* Extend the stack space available. Don't do that if dumping,
--
2.5.5