From 883d68803d17d6f64cdabf2c8ef846345e2d0094 Mon Sep 17 00:00:00 2001
From: Julien Lepiller <julien@lepiller.eu>
Date: Sun, 19 Feb 2023 10:20:19 +0100
Subject: [PATCH] Dynamically allocate the alternate signal stack.

This patch is a backport of https://github.com/ocaml/ocaml/pull/10266.
---
 ocaml-src/asmrun/signals_asm.c | 19 +++++++++++--------
 1 file changed, 11 insertions(+), 8 deletions(-)

diff --git a/ocaml-src/asmrun/signals_asm.c b/ocaml-src/asmrun/signals_asm.c
index 3895d75..d37b481 100644
--- a/ocaml-src/asmrun/signals_asm.c
+++ b/ocaml-src/asmrun/signals_asm.c
@@ -182,7 +182,6 @@ DECLARE_SIGNAL_HANDLER(trap_handler)
 #ifdef HAS_STACK_OVERFLOW_DETECTION
 
 static char * system_stack_top;
-static char sig_alt_stack[SIGSTKSZ];
 
 #if defined(SYS_linux)
 /* PR#4746: recent Linux kernels with support for stack randomization
@@ -274,15 +273,19 @@ void caml_init_signals(void)
 #ifdef HAS_STACK_OVERFLOW_DETECTION
   {
     stack_t stk;
-    struct sigaction act;
-    stk.ss_sp = sig_alt_stack;
+    stk.ss_sp = malloc(SIGSTKSZ);
     stk.ss_size = SIGSTKSZ;
     stk.ss_flags = 0;
-    SET_SIGACT(act, segv_handler);
-    act.sa_flags |= SA_ONSTACK | SA_NODEFER;
-    sigemptyset(&act.sa_mask);
-    system_stack_top = (char *) &act;
-    if (sigaltstack(&stk, NULL) == 0) { sigaction(SIGSEGV, &act, NULL); }
+    if (stk.ss_sp != NULL) {
+      if (sigaltstack(&stk, NULL) != -1) {
+        struct sigaction act;
+        SET_SIGACT(act, segv_handler);
+        act.sa_flags |= SA_ONSTACK | SA_NODEFER;
+        sigemptyset(&act.sa_mask);
+        system_stack_top = (char *) &act;
+        sigaction(SIGSEGV, &act, NULL);
+      }
+    }
   }
 #endif
 }
-- 
2.38.1

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<div class='path'>path: <a href='/guix/log/?id=90d192b2f7f060e4d2e5c827533e6fe0545a04ba'>root</a>/<a href='/guix/log/etc?id=90d192b2f7f060e4d2e5c827533e6fe0545a04ba'>etc</a>/<a href='/guix/log/etc/guix-publish.service.in?id=90d192b2f7f060e4d2e5c827533e6fe0545a04ba'>guix-publish.service.in</a></div><div class='content'><table class='list nowrap'><tr class='nohover'><th class='left'>Age</th><th class='left'>Commit message (<a href='/guix/log/etc/guix-publish.service.in?id=90d192b2f7f060e4d2e5c827533e6fe0545a04ba&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2019-06-05 17:27:22 +0200'>2019-06-05</span></td><td><a href='/guix/commit/etc/guix-publish.service.in?id=a5ca4a63426f5e24c13b93bde95511e9d89757f5'>etc: Fix GUIX_LOCPATH quoting in 'guix-publish.service' file.</a><span class='msg-avail'>...<span class='msg-tooltip'>This is a followup to 579d17b70dac067f8194ede46513400b91ac136a.

* etc/guix-publish.service.in (Environment): Move GUIX_LOCPATH inside
the quotes.
</span></span></td><td>Jack Hill</td></tr>
<tr><td><span title='2019-05-13 23:46:08 +0200'>2019-05-13</span></td><td><a href='/guix/commit/etc/guix-publish.service.in?id=489d6c0dc03f1d95a3fefa6301f36cac9b50b2c3'>Set 'LC_ALL=en_US.utf8' in systemd '.service' files.</a><span class='msg-avail'>...<span class='msg-tooltip'>Fixes &lt;https://bugs.gnu.org/35671&gt;.

* etc/guix-daemon.service.in (Environment): Quote the 'GUIX_LOCPATH'
value; add 'LC_ALL'.
* etc/guix-publish.service.in (Environment): Likewise.
</span></span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2018-11-23 15:42:01 +0100'>2018-11-23</span></td><td><a href='/guix/commit/etc/guix-publish.service.in?id=e9926f80c6553fde50ce1fcfd38d6370f841efd2'>build: Binary tarball now populates the "current-guix" profile.</a><span class='msg-avail'>...<span class='msg-tooltip'>* Makefile.am (guix-binary.%.tar.xz): Pass
'--profile-name=current-guix'.  Remove glibc and glibc-utf8-locales.
* doc/guix.texi (Binary Installation): Update accordingly.
* etc/guix-install.sh
* etc/guix-install.sh (sys_create_store, sys_enable_guix_daemon)
(sys_authorize_build_farms): Likewise.
* etc/guix-publish.conf.in, etc/guix-publish.service.in,
etc/guix-daemon.conf.in, etc/guix-daemon.service.in: Update file names
accordingly.
</span></span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2017-03-06 13:25:51 -0500'>2017-03-06</span></td><td><a href='/guix/commit/etc/guix-publish.service.in?id=613d0895b92c677e0639d5e77c55043e38e020c8'>build: Don't embed absolute paths in .service and .conf service files.</a><span class='msg-avail'>...<span class='msg-tooltip'>Otherwise, users will be stuck running an old copy of guix and the guix-daemon
if they copy the service files instead of symlinking them.

* etc/guix-daemon.conf.in, etc/guix-daemon.service.in, etc/guix-publish.conf.in,
etc/guix-publish.service.in: Expand @localstatedir@ instead of @bindir@.
* nix/local.mk (etc/guix-%.service, etc/guix-%.conf): Use @localstatedir@
instead of @bindir@.
</span></span></td><td>Leo Famulari</td></tr>