From bccbd141d242c1c57e73c3213371b80779377419 Mon Sep 17 00:00:00 2001
From: Joakim Tjernlund <joakim.tjernlund@transmode.se>
Date: Thu, 25 Jun 2009 16:40:06 +0100
Subject: [PATCH] [lib] Add support for backtrace on more platforms

* lib/sigevent.c: (program_counter) extend to support more platforms. Joint
  effort with Paul Jakma.

(cherry picked from commit b166ea2dda9f04a8b75e0bf5adb7064580695f22)
---
 configure.ac   | 12 ++++++++++++
 lib/sigevent.c | 32 ++++++++++++++++++++++++++++----
 2 files changed, 40 insertions(+), 4 deletions(-)

diff --git a/configure.ac b/configure.ac
index 852b63d6ae..5461e362be 100755
--- a/configure.ac
+++ b/configure.ac
@@ -580,6 +580,18 @@ AC_CHECK_HEADERS([ucontext.h], [], [],
 QUAGGA_INCLUDES
 ])
 
+m4_define([UCONTEXT_INCLUDES],
+[#include <ucontext.h>])dnl
+
+AC_CHECK_MEMBERS([ucontext_t.uc_mcontext.uc_regs],
+  [], [], [UCONTEXT_INCLUDES])
+AC_CHECK_MEMBERS([ucontext_t.uc_mcontext.regs],
+  [AC_CHECK_MEMBERS([ucontext_t.uc_mcontext.regs.nip],
+   [], [], [UCONTEXT_INCLUDES])],
+  [], [UCONTEXT_INCLUDES])
+AC_CHECK_MEMBERS([ucontext_t.uc_mcontext.gregs],
+  [], [], [UCONTEXT_INCLUDES])
+
 m4_define([QUAGGA_INCLUDES],
 QUAGGA_INCLUDES
 [#if HAVE_SYS_UN_H
diff --git a/lib/sigevent.c b/lib/sigevent.c
index 7d08fd97ce..c80a729012 100644
--- a/lib/sigevent.c
+++ b/lib/sigevent.c
@@ -175,11 +175,35 @@ program_counter(void *context)
 {
 #ifdef HAVE_UCONTEXT_H
 #ifdef GNU_LINUX
-#ifdef REG_EIP
-  if (context)
-    return (void *)(((ucontext_t *)context)->uc_mcontext.gregs[REG_EIP]);
-#endif /* REG_EIP */
+  /* these are from GNU libc, rather than Linux, strictly speaking */
+# if defined(REG_EIP)
+#  define REG_INDEX REG_EIP
+# elif defined(REG_RIP)
+#  define REG_INDEX REG_RIP
+# elif defined(__powerpc__)
+#  define REG_INDEX 32
+# endif
+#elif defined(SUNOS_5) /* !GNU_LINUX */
+# define REG_INDEX REG_PC
 #endif /* GNU_LINUX */
+
+#ifdef REG_INDEX
+# ifdef HAVE_UCONTEXT_T_UC_MCONTEXT_GREGS
+#  define REGS gregs[REG_INDEX]
+# elif defined(HAVE_UCONTEXT_T_UC_MCONTEXT_UC_REGS)
+#  define REGS uc_regs->gregs[REG_INDEX]
+# endif /* HAVE_UCONTEXT_T_UC_MCONTEXT_GREGS */
+#endif /* REG_INDEX */
+
+#ifdef REGS
+  if (context)
+    return (void *)(((ucontext_t *)context)->uc_mcontext.REGS);
+#elif defined(HAVE_UCONTEXT_T_UC_MCONTEXT_REGS__NIP) 
+  /* older Linux / struct pt_regs ? */
+  if (context)
+    return (void *)(((ucontext_t *)context)->uc_mcontext.regs->nip);
+#endif /* REGS */
+
 #endif /* HAVE_UCONTEXT_H */
   return NULL;
 }
-- 
2.39.5