From 39ec1bd6dc73d2510d149456492d68d32d6a1f07 Mon Sep 17 00:00:00 2001
From: "hp.com!davidm" <hp.com!davidm>
Date: Tue, 3 May 2005 09:13:17 +0000
Subject: [PATCH] (unw_is_signal_frame): Always return 0 for NULL IP.

2004/12/02 18:37:47-08:00 hp.com!davidm
(unw_is_signal_frame): Implement it.

2004/12/02 00:40:45-08:00 mostang.com!davidm

(Logical change 1.290)
---
 src/hppa/Gis_signal_frame.c | 74 +++++++++++++++++++++++++++++++++++++
 1 file changed, 74 insertions(+)
 create mode 100644 src/hppa/Gis_signal_frame.c

diff --git a/src/hppa/Gis_signal_frame.c b/src/hppa/Gis_signal_frame.c
new file mode 100644
index 00000000..202b5703
--- /dev/null
+++ b/src/hppa/Gis_signal_frame.c
@@ -0,0 +1,74 @@
+/* libunwind - a platform-independent unwind library
+   Copyright (C) 2004 Hewlett-Packard Co
+	Contributed by David Mosberger-Tang <davidm@hpl.hp.com>
+
+This file is part of libunwind.
+
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of this software and associated documentation files (the
+"Software"), to deal in the Software without restriction, including
+without limitation the rights to use, copy, modify, merge, publish,
+distribute, sublicense, and/or sell copies of the Software, and to
+permit persons to whom the Software is furnished to do so, subject to
+the following conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.  */
+
+#include "unwind_i.h"
+
+PROTECTED int
+unw_is_signal_frame (unw_cursor_t *cursor)
+{
+#ifdef __linux__ 
+  struct cursor *c = (struct cursor *) cursor;
+  unw_word_t w0, w1, w2, w3, ip;
+  unw_addr_space_t as;
+  unw_accessors_t *a;
+  void *arg;
+  int ret;
+
+  as = c->dwarf.as;
+  a = unw_get_accessors (as);
+  arg = c->dwarf.as_arg;
+
+  /* Check if IP points at sigreturn() sequence.  On Linux, this normally is:
+
+    rt_sigreturn:
+       0x34190000 ldi 0, %r25
+       0x3414015a ldi __NR_rt_sigreturn,%r20
+       0xe4008200 be,l 0x100(%sr2,%r0),%sr0,%r31
+       0x08000240 nop
+
+     When a signal interrupts a system call, the first word is instead:
+
+       0x34190002 ldi 1, %r25
+  */
+  ip = c->dwarf.ip;
+  if (!ip)
+    return 0;
+  if ((ret = (*a->access_mem) (as, ip, &w0, 0, arg)) < 0
+      || (ret = (*a->access_mem) (as, ip + 4, &w1, 0, arg)) < 0
+      || (ret = (*a->access_mem) (as, ip + 8, &w2, 0, arg)) < 0
+      || (ret = (*a->access_mem) (as, ip + 12, &w3, 0, arg)) < 0)
+    {
+      Debug (1, "failed to read sigreturn code (ret=%d)\n", ret);
+      return ret;
+    }
+  ret = ((w0 == 0x34190000 || w0 == 0x34190002)
+	 && w1 == 0x3414015a && w2 == 0xe4008200 && w3 == 0x08000240);
+  Debug (1, "(cursor=%p, ip=0x%08lx) -> %d\n", c, (unsigned) ip, ret);
+  return ret;
+#else
+  printf ("%s: implement me\n", __FUNCTION__);
+#endif
+  return -UNW_ENOINFO;
+}