Attached patch following Philip Guenther's suggestion.

For now a simple implementation should be enough until a better
implementation can be agreed for all *BSD.

Best,
From c29830f974c73e9bd61956858b832e0cab54f1ca Mon Sep 17 00:00:00 2001
From: Ricardo Branco <rbranco@suse.de>
Date: Wed, 16 Apr 2025 10:16:13 +0200
Subject: [PATCH] Add POSIX psiginfo(3) call

---
 include/signal.h          |  1 +
 lib/libc/Symbols.list     |  1 +
 lib/libc/gen/Makefile.inc |  4 ++--
 lib/libc/gen/psiginfo.c   | 42 +++++++++++++++++++++++++++++++++++++++
 lib/libc/gen/psignal.3    | 21 +++++++++++++++++++-
 lib/libc/gen/psignal.c    |  1 +
 lib/libc/hidden/signal.h  |  3 ++-
 7 files changed, 69 insertions(+), 4 deletions(-)
 create mode 100644 lib/libc/gen/psiginfo.c

diff --git a/include/signal.h b/include/signal.h
index 07982bd75a1..7506ef0fbe7 100644
--- a/include/signal.h
+++ b/include/signal.h
@@ -132,6 +132,7 @@ int	thrkill(pid_t _tid, int _signum, void *_tcb);
 int	sigwait(const sigset_t *__restrict, int *__restrict);
 #endif
 #if __BSD_VISIBLE ||  __POSIX_VISIBLE >= 200809
+void	psiginfo(const siginfo_t *, const char *);
 void	psignal(unsigned int, const char *);
 #endif
 #endif /* __BSD_VISIBLE || __POSIX_VISIBLE || __XPG_VISIBLE */
diff --git a/lib/libc/Symbols.list b/lib/libc/Symbols.list
index 7b1dbdeca69..12e04f89fb4 100644
--- a/lib/libc/Symbols.list
+++ b/lib/libc/Symbols.list
@@ -745,6 +745,7 @@ posix_spawnattr_setschedpolicy
 posix_spawnattr_setsigdefault
 posix_spawnattr_setsigmask
 posix_spawnp
+psiginfo
 psignal
 pw_dup
 raise
diff --git a/lib/libc/gen/Makefile.inc b/lib/libc/gen/Makefile.inc
index f87cc7a89e5..4b82d1e645c 100644
--- a/lib/libc/gen/Makefile.inc
+++ b/lib/libc/gen/Makefile.inc
@@ -14,8 +14,8 @@ SRCS+=  alarm.c assert.c auth_subr.c authenticate.c \
         getloadavg.c getlogin.c getmntinfo.c getnetgrent.c getpagesize.c \
         getprogname.c getpwent.c getttyent.c getusershell.c glob.c \
         initgroups.c isatty.c isctype.c isfdtype.c isfinite.c isinf.c \
-        isnan.c isnormal.c signbit.c lockf.c login_cap.c nice.c \
-        nlist.c nftw.c opendir.c pause.c popen.c posix_spawn.c psignal.c \
+        isnan.c isnormal.c signbit.c lockf.c login_cap.c nice.c nlist.c \
+        nftw.c opendir.c pause.c popen.c posix_spawn.c psignal.c psiginfo.c \
         pw_dup.c pwcache.c raise.c readdir.c readdir_r.c readpassphrase.c \
         rewinddir.c scandir.c seekdir.c setdomainname.c sethostname.c \
         setprogname.c setmode.c setproctitle.c shm_open.c \
diff --git a/lib/libc/gen/psiginfo.c b/lib/libc/gen/psiginfo.c
new file mode 100644
index 00000000000..65ab516499c
--- /dev/null
+++ b/lib/libc/gen/psiginfo.c
@@ -0,0 +1,42 @@
+/*	$OpenBSD	*/
+/*
+ * Copyright (c) 1983, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+/*
+ * Print the signal information
+ * along with the supplied message.
+ */
+#include <sys/types.h>
+#include <signal.h>
+
+void
+psiginfo(const siginfo_t *si, const char *s)
+{
+	psignal(si->si_signo, s);
+}
diff --git a/lib/libc/gen/psignal.3 b/lib/libc/gen/psignal.3
index 3fd2ebbf7bf..015e968a107 100644
--- a/lib/libc/gen/psignal.3
+++ b/lib/libc/gen/psignal.3
@@ -27,11 +27,12 @@
 .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 .\" SUCH DAMAGE.
 .\"
-.Dd $Mdocdate: May 16 2019 $
+.Dd $Mdocdate: Apr 16 2025 $
 .Dt PSIGNAL 3
 .Os
 .Sh NAME
 .Nm psignal ,
+.Nm psiginfo ,
 .Nm sys_siglist ,
 .Nm sys_signame
 .Nd system signal messages
@@ -39,6 +40,7 @@
 .In signal.h
 .Ft void
 .Fn psignal "unsigned int sig" "const char *s"
+.Fn psiginfo "const siginfo_t *si" "const char *s"
 .Vt extern char *sys_siglist[];
 .Vt extern char *sys_signame[];
 .Sh DESCRIPTION
@@ -64,6 +66,16 @@ the string
 .Dq Unknown signal
 is produced.
 .Pp
+The
+.Fn psiginfo
+function is similar to
+.Fn psignal ,
+except that the signal number information is taken from the
+.Fa si
+argument which is a
+.Vt siginfo_t
+structure.
+.Pp
 The message strings can be accessed directly using the external array
 .Va sys_siglist ,
 indexed by recognized signal numbers.
@@ -87,6 +99,13 @@ The
 .Fn psignal
 function appeared in
 .Bx 4.2 .
+The
+.Fn psiginfo
+function appeared in
+.Fx 15.0 ,
+.Nx 6.0 ,
+and
+.Dx 4.1 .
 .Sh CAVEATS
 On systems other than
 .Ox ,
diff --git a/lib/libc/gen/psignal.c b/lib/libc/gen/psignal.c
index dca921d5a5a..6863d7cc05e 100644
--- a/lib/libc/gen/psignal.c
+++ b/lib/libc/gen/psignal.c
@@ -61,3 +61,4 @@ psignal(unsigned int sig, const char *s)
 	iov[niov+1].iov_len = 1;
 	(void)writev(STDERR_FILENO, iov, niov+2);
 }
+DEF_WEAK(psignal);
diff --git a/lib/libc/hidden/signal.h b/lib/libc/hidden/signal.h
index 7fdfcef7532..7fff33ee352 100644
--- a/lib/libc/hidden/signal.h
+++ b/lib/libc/hidden/signal.h
@@ -52,7 +52,8 @@ PROTO_NORMAL(__errno);
 PROTO_DEPRECATED(bsd_signal);
 PROTO_NORMAL(kill);             /* wrap to ban SIGTHR? */
 PROTO_DEPRECATED(killpg);
-PROTO_DEPRECATED(psignal);
+PROTO_DEPRECATED(psiginfo);
+PROTO_NORMAL(psignal);
 PROTO_DEPRECATED(pthread_sigmask);
 PROTO_NORMAL(raise);
 PROTO_WRAP(sigaction);
-- 
2.50.1

• 0001-Add-POSIX-psiginfo-3-call.patch (6K)