From 92d72e3b846a8ba258831a30510742d3b7b53609 Mon Sep 17 00:00:00 2001
From: Eric Blake <eblake@redhat.com>
Date: Fri, 31 Dec 2010 12:36:15 -0700
Subject: [PATCH] signal: work around Haiku issue with SIGBUS

* lib/siglist.h: Add comment.
* lib/sig2str.c (numname_table): Swap SIGBUS order, to match
strsignal's favoring of SIGSEGV.
* tests/test-signal.c (main): Avoid test failure.
* doc/posix-headers/signal.texi (signal.h): Document the issue.
Reported by Scott McCreary.

Signed-off-by: Eric Blake <eblake@redhat.com>
---
 ChangeLog                     |  8 ++++++++
 doc/posix-headers/signal.texi |  4 ++++
 lib/sig2str.c                 | 10 ++++++----
 lib/siglist.h                 |  3 +++
 tests/test-signal.c           |  3 ++-
 5 files changed, 23 insertions(+), 5 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index 5e319f92c..d638bdf9c 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -350,6 +350,14 @@
 
 2010-12-31  Eric Blake  <eblake@redhat.com>
 
+	signal: work around Haiku issue with SIGBUS
+	* lib/siglist.h: Add comment.
+	* lib/sig2str.c (numname_table): Swap SIGBUS order, to match
+	strsignal's favoring of SIGSEGV.
+	* tests/test-signal.c (main): Avoid test failure.
+	* doc/posix-headers/signal.texi (signal.h): Document the issue.
+	Reported by Scott McCreary.
+
 	nl_langinfo: fix YESEXPR on Irix 6.5
 	* m4/nl_langinfo.m4 (gl_FUNC_NL_LANGINFO): Test for Irix bug.
 	* lib/nl_langinfo.c (rpl_nl_langinfo): Work around it.
diff --git a/doc/posix-headers/signal.texi b/doc/posix-headers/signal.texi
index 9056d1e3e..77a54323c 100644
--- a/doc/posix-headers/signal.texi
+++ b/doc/posix-headers/signal.texi
@@ -39,4 +39,8 @@ mingw.
 The macros @code{SIGRTMIN} and @code{SIGRTMAX} expand to an expression of type
 @code{long} instead of @code{int} on some platforms:
 OSF/1 5.1.
+@item
+The macro @code{SIGBUS} is set to the same value as @code{SIGSEGV},
+rather than being a distinct signal, on some platforms:
+Haiku.
 @end itemize
diff --git a/lib/sig2str.c b/lib/sig2str.c
index 770f88c00..70faa66c3 100644
--- a/lib/sig2str.c
+++ b/lib/sig2str.c
@@ -41,7 +41,7 @@
 static struct numname { int num; char const name[8]; } numname_table[] =
   {
     /* Signals required by POSIX 1003.1-2001 base, listed in
-       traditional numeric order.  */
+       traditional numeric order where possible.  */
 #ifdef SIGHUP
     NUMNAME (HUP),
 #endif
@@ -66,12 +66,14 @@ static struct numname { int num; char const name[8]; } numname_table[] =
 #ifdef SIGKILL
     NUMNAME (KILL),
 #endif
-#ifdef SIGBUS
-    NUMNAME (BUS),
-#endif
 #ifdef SIGSEGV
     NUMNAME (SEGV),
 #endif
+    /* On Haiku, SIGSEGV == SIGBUS, but we prefer SIGSEGV to match
+       strsignal.c output, so SIGBUS must be listed second.  */
+#ifdef SIGBUS
+    NUMNAME (BUS),
+#endif
 #ifdef SIGPIPE
     NUMNAME (PIPE),
 #endif
diff --git a/lib/siglist.h b/lib/siglist.h
index 8c86d9b22..104bc6831 100644
--- a/lib/siglist.h
+++ b/lib/siglist.h
@@ -23,6 +23,9 @@
 
 /* This file is included multiple times.  */
 
+/* Duplicate values (such as SIGBUS==SIGSEGV on Haiku) favor the last
+   list entry.  */
+
 /* Standard signals  */
 #ifdef SIGHUP
   init_sig (SIGHUP, "HUP", N_("Hangup"))
diff --git a/tests/test-signal.c b/tests/test-signal.c
index 116fe0527..7103e1ff1 100644
--- a/tests/test-signal.c
+++ b/tests/test-signal.c
@@ -59,7 +59,8 @@ main (void)
 #ifdef SIGALRM
     case SIGALRM:
 #endif
-#ifdef SIGBUS
+      /* On Haiku, SIGBUS is mistakenly equal to SIGSEGV.  */
+#if defined SIGBUS && SIGBUS != SIGSEGV
     case SIGBUS:
 #endif
 #ifdef SIGCHLD
-- 
2.11.0