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

 value='author'>author</option>
<option value='committer'>committer</option>
<option value='range'>range</option>
</select>
<input class='txt' type='search' size='10' name='q' value=''/>
<input type='submit' value='search'/>
</form>
</td></tr></table>
<div class='path'>path: <a href='/guix/log/?id=628bdd6223135e4447a6f71e580f8124bffac1ef'>root</a>/<a href='/guix/log/tests?id=628bdd6223135e4447a6f71e580f8124bffac1ef'>tests</a>/<a href='/guix/log/tests/syscalls.scm?id=628bdd6223135e4447a6f71e580f8124bffac1ef'>syscalls.scm</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/tests/syscalls.scm?id=628bdd6223135e4447a6f71e580f8124bffac1ef&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2024-08-21 00:52:38 +0200'>2024-08-21</span></td><td><a href='/guix/commit/tests/syscalls.scm?id=96cd163c14e68c66c6a4cf0b18261fc454f8c1ba'>syscalls: Add ‘mode’ parameter to ‘lock-file’.</a><span class='msg-avail'>...<span class='msg-tooltip'>* guix/build/syscalls.scm (lock-file): Add ‘mode’ parameter and honor it.
* tests/syscalls.scm ("lock-file + unlock-file"): New test.

Change-Id: I113fb4a8b35dd8782b9c0991574e39a4b4393333
</span></span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2024-05-13 16:31:35 +0200'>2024-05-13</span></td><td><a href='/guix/commit/tests/syscalls.scm?id=7ca9809cdbfe326294a5d8c64b4b8c59d0e76bea'>tests: Skip ‘terminal-string-width’ test on encodings other than UTF-8.</a><span class='msg-avail'>...<span class='msg-tooltip'>* tests/syscalls.scm ("terminal-string-width Japanese"): Skip when the
encoding of (current-output-port) is not UTF-8.

Reported-by: Ashvith Shetty &lt;ashvithshetty10@gmail.com&gt;
Change-Id: Ic284dd088d6b148d6fcb457290a28fdb0838b83d
</span></span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2023-11-25 16:29:25 +0100'>2023-11-25</span></td><td><a href='/guix/commit/tests/syscalls.scm?id=e04f8fe4ea50f81847cad98a5dc6b32c27b81ea2'>tests: Use ‘test-equal’ for ‘terminal-string-width’ tests.</a><span class='msg-avail'>...<span class='msg-tooltip'>* tests/syscalls.scm ("terminal-string-width English")
("terminal-string-width Japanese"): Use ‘test-equal’.

Change-Id: I3791b2e4c9e35735db6c6da995da8ef0f9a71804
</span></span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2023-11-11 11:07:27 +0100'>2023-11-11</span></td><td><a href='/guix/commit/tests/syscalls.scm?id=fd11d7fbf8e0fcc61ff764dcc0ab737971afc55a'>guix: syscalls: Add terminal-string-width.</a><span class='msg-avail'>...<span class='msg-tooltip'>* guix/build/syscalls.scm (terminal-width): New procedure.
* tests/syscalls.scm: Add tests.

Change-Id: I6c2caa9fbaffb1e8f4b8933103399be970d5a8f3
</span></span></td><td>Julien Lepiller</td></tr>
<tr><td><span title='2021-10-26 12:46:27 +0200'>2021-10-26</span></td><td><a href='/guix/commit/tests/syscalls.scm?id=f87371bf3e952a211782311dad2971c8820a5150'>syscalls: Add 'openpty' and 'login-tty'.</a><span class='msg-avail'>...<span class='msg-tooltip'>* guix/build/syscalls.scm (openpty, login-pty): New procedures.
* tests/syscalls.scm ("openpty", "openpty + login-tty"): New tests.
</span></span></td><td>Ludovic Courtès</td></tr>