Based on 4dffec1459f50ac9f8f67ccfcb79836b4ed5a50e Mon Sep 17 00:00:00 2001
From: Lennart Poettering <lennart@poettering.net>
Date: Fri, 24 Oct 2014 13:44:45 +0200
Subject: [PATCH] manager: Linux on hppa has fewer rtsigs, hence avoid using
 the higher ones there

https://bugs.freedesktop.org/show_bug.cgi?id=84931
---
 src/core/manager.c |   29 +++++++++++++++++++++++++++--
 1 file changed, 27 insertions(+), 2 deletions(-)

--- src/core/manager.c
+++ src/core/manager.c	2014-10-29 14:02:28.635837997 +0000
@@ -340,11 +340,14 @@ static int manager_setup_signals(Manager
 
         assert(m);
 
-        /* We are not interested in SIGSTOP and friends. */
         assert_se(sigaction(SIGCHLD, &sa, NULL) == 0);
 
-        assert_se(sigemptyset(&mask) == 0);
+        /* We make liberal use of realtime signals here. On
+         * Linux/glibc we have 30 of them (with the exception of Linux
+         * on hppa, see below), between SIGRTMIN+0 ... SIGRTMIN+30
+         * (aka SIGRTMAX). */
 
+        assert_se(sigemptyset(&mask) == 0);
         sigset_add_many(&mask,
                         SIGCHLD,     /* Child died */
                         SIGTERM,     /* Reexecute daemon */
@@ -354,6 +357,7 @@ static int manager_setup_signals(Manager
                         SIGINT,      /* Kernel sends us this on control-alt-del */
                         SIGWINCH,    /* Kernel sends us this on kbrequest (alt-arrowup) */
                         SIGPWR,      /* Some kernel drivers and upsd send us this on power failure */
+
                         SIGRTMIN+0,  /* systemd: start default.target */
                         SIGRTMIN+1,  /* systemd: isolate rescue.target */
                         SIGRTMIN+2,  /* systemd: isolate emergency.target */
@@ -361,19 +365,40 @@ static int manager_setup_signals(Manager
                         SIGRTMIN+4,  /* systemd: start poweroff.target */
                         SIGRTMIN+5,  /* systemd: start reboot.target */
                         SIGRTMIN+6,  /* systemd: start kexec.target */
+
+                        /* ... space for more special targets ... */
+
                         SIGRTMIN+13, /* systemd: Immediate halt */
                         SIGRTMIN+14, /* systemd: Immediate poweroff */
                         SIGRTMIN+15, /* systemd: Immediate reboot */
                         SIGRTMIN+16, /* systemd: Immediate kexec */
+
+                        /* ... space for more immediate system state changes ... */
+
                         SIGRTMIN+20, /* systemd: enable status messages */
                         SIGRTMIN+21, /* systemd: disable status messages */
                         SIGRTMIN+22, /* systemd: set log level to LOG_DEBUG */
                         SIGRTMIN+23, /* systemd: set log level to LOG_INFO */
                         SIGRTMIN+24, /* systemd: Immediate exit (--user only) */
+
+                        /* .. one free signal here ... */
+
+#if !defined(__hppa64__) && !defined(__hppa__)
+                        /* Apparently Linux on hppa has fewer RT
+                         * signals (SIGRTMAX is SIGRTMIN+25 there),
+                         * hence let's not try to make use of them
+                         * here. Since these commands are accessible
+                         * by different means and only really a safety
+                         * net, the missing functionality on hppa
+                         * shouldn't matter. */
+
                         SIGRTMIN+26, /* systemd: set log target to journal-or-kmsg */
                         SIGRTMIN+27, /* systemd: set log target to console */
                         SIGRTMIN+28, /* systemd: set log target to kmsg */
                         SIGRTMIN+29, /* systemd: set log target to syslog-or-kmsg */
+
+                        /* ... one free signal here SIGRTMIN+30 ... */
+#endif
                         -1);
         assert_se(sigprocmask(SIG_SETMASK, &mask, NULL) == 0);
 
