* i386bsd-nat.c: Include <signal.h>, <stddef.h> and

<sys/sysctl.h>.
(store_inferior_registers): Wrap long line.
(i386bsd_dr_get_status): Fix typo in comment.
(_initialize_i386bsd_nat): New function.  * i386bsd-tdep.c: New
file.  * config/i386/tm-fbsd.h (IN_SIGTRAMP): New define.
(i386bsd_in_sigtramp): New prototype.
(SIGTRAMP_START, SIGTRAMP_END): Redefine in terms...
(i386bsd_sigtramp_start, i386bsd_sigtramp_end): ...these new
(external) variables.
(SIGCONTEXT_PC_OFFSET): Removed.
(FRAME_SAVED_PC): New define.
(i386bsd_frame_saved_pc): New function.  * config/i386/fbsd.mt
(TDEPFILES): Add i386bsd-tdep.o.

gdb/ChangeLog

@@ -1,3 +1,20 @@
+2001-07-13  Mark Kettenis  <kettenis@gnu.org>
+
+	* i386bsd-nat.c: Include <signal.h>, <stddef.h> and
+	<sys/sysctl.h>.
+	(store_inferior_registers): Wrap long line.
+	(i386bsd_dr_get_status): Fix typo in comment.
+	(_initialize_i386bsd_nat): New function.  * i386bsd-tdep.c: New
+	file.  * config/i386/tm-fbsd.h (IN_SIGTRAMP): New define.
+	(i386bsd_in_sigtramp): New prototype.
+	(SIGTRAMP_START, SIGTRAMP_END): Redefine in terms...
+	(i386bsd_sigtramp_start, i386bsd_sigtramp_end): ...these new
+	(external) variables.
+	(SIGCONTEXT_PC_OFFSET): Removed.
+	(FRAME_SAVED_PC): New define.
+	(i386bsd_frame_saved_pc): New function.  * config/i386/fbsd.mt
+	(TDEPFILES): Add i386bsd-tdep.o.
+
 2001-07-12  Daniel Jacobowitz  <drow@mvista.com>
 
 	* mips-linux-tdep.c (_initialize_mips_linux_tdep):  Use ISO C

gdb/config/i386/fbsd.mt

@@ -1,3 +1,3 @@
 # Target: Intel 386 running FreeBSD
-TDEPFILES= i386-tdep.o i387-tdep.o
+TDEPFILES= i386-tdep.o i387-tdep.o i386bsd-tdep.o
 TM_FILE= tm-fbsd.h

gdb/config/i386/tm-fbsd.h

@@ -1,5 +1,5 @@
 /* Target-dependent definitions for FreeBSD/i386.
-   Copyright 1997, 1999, 2000 Free Software Foundation, Inc.
+   Copyright 1997, 1999, 2000, 2001 Free Software Foundation, Inc.
 
    This file is part of GDB.
 
@@ -40,21 +40,31 @@
 /* Figure out where the longjmp will land.  Store the address that
    longjmp will jump to in *ADDR, and return non-zero if successful.  */
 
-extern int get_longjmp_target (CORE_ADDR *addr);
 #define GET_LONGJMP_TARGET(addr) get_longjmp_target (addr)
+extern int get_longjmp_target (CORE_ADDR *addr);
 
 
 /* Support for signal handlers.  */
 
-/* The sigtramp is above the user stack and immediately below
+#define IN_SIGTRAMP(pc, name) i386bsd_in_sigtramp (pc, name)
-   the user area.  Using constants here allows for cross debugging.
+extern int i386bsd_in_sigtramp (CORE_ADDR pc, char *name);
-   These are tested for FreeBSD 3.4.  */
 
-#define SIGTRAMP_START(pc)	0xbfbfdf20
+/* These defines allow the recognition of sigtramps as a function name
-#define SIGTRAMP_END(pc)	0xbfbfdff0
+   <sigtramp>.
 
-/* Offset to saved PC in sigcontext, from <sys/signal.h>.  */
+   FIXME: kettenis/2001-07-13: These should be added to the target
-#define SIGCONTEXT_PC_OFFSET 20
+   vector and turned into functions when we go "multi-arch".  */
+
+#define SIGTRAMP_START(pc) i386bsd_sigtramp_start
+#define SIGTRAMP_END(pc) i386bsd_sigtramp_end
+extern CORE_ADDR i386bsd_sigtramp_start;
+extern CORE_ADDR i386bsd_sigtramp_end;
+
+/* Override FRAME_SAVED_PC to enable the recognition of signal handlers.  */
+
+#undef FRAME_SAVED_PC
+#define FRAME_SAVED_PC(frame) i386bsd_frame_saved_pc (frame)
+extern CORE_ADDR i386bsd_frame_saved_pc (struct frame_info *frame);
 
 
 /* Shared library support.  */

gdb/i386bsd-nat.c

@@ -23,6 +23,8 @@
 #include "regcache.h"
 
 #include "gdb_assert.h"
+#include <signal.h>
+#include <stddef.h>
 #include <sys/types.h>
 #include <sys/ptrace.h>
 #include <machine/reg.h>
@@ -198,7 +200,8 @@ store_inferior_registers (int regno)
 
   fill_gregset (&gregs, regno);
 
-  if (ptrace (PT_SETREGS, PIDGET (inferior_ptid), (PTRACE_ARG3_TYPE) &gregs, 0) == -1)
+  if (ptrace (PT_SETREGS, PIDGET (inferior_ptid),
+	      (PTRACE_ARG3_TYPE) &gregs, 0) == -1)
     perror_with_name ("Couldn't write registers");
 
   if (regno == -1 || regno >= FP0_REGNUM)
@@ -279,7 +282,7 @@ i386bsd_dr_get_status (void)
   /* FIXME: kettenis/2001-03-31: Calling perror_with_name if the
      ptrace call fails breaks debugging remote targets.  The correct
      way to fix this is to add the hardware breakpoint and watchpoint
-     stuff to the target vectore.  For now, just return zero if the
+     stuff to the target vector.  For now, just return zero if the
      ptrace call fails.  */
   if (ptrace (PT_GETDBREGS, PIDGET (inferior_ptid),
 	      (PTRACE_ARG3_TYPE) & dbregs, 0) == -1)
@@ -316,3 +319,45 @@ kernel_u_size (void)
 {
   return (sizeof (struct user));
 }
+
+/* See i386bsd-tdep.c.  */
+extern int i386bsd_sigcontext_pc_offset;
+
+#include <sys/sysctl.h>
+
+void
+_initialize_i386bsd_nat (void)
+{
+  /* To support the recognition of signal handlers, i386bsd-tdep.c
+     hardcodes some constants.  Inclusion of this file means that we
+     are compiling a native debugger, which means that we can use the
+     system header files and sysctl(3) to get at the relevant
+     information.  */
+
+  /* Override the default value for the offset of the program counter
+     in the sigcontext structure.  */
+  i386bsd_sigcontext_pc_offset = offsetof (struct sigcontext, sc_pc);
+
+  /* FreeBSD provides a kern.ps_strings sysctl that we can use to
+     locate the sigtramp.  That way we can still recognize a sigtramp
+     if it's location is changed in a new kernel.  Of course this is
+     still based on the assumption that the sigtramp is placed
+     directly under the location where the program arguments and
+     environment can be found.  */
+#ifdef KERN_PS_STRINGS
+  {
+    int mib[2];
+    int ps_strings;
+    size_t len;
+
+    mib[0] = CTL_KERN;
+    mib[1] = KERN_PS_STRINGS;
+    len = sizeof (ps_strings);
+    if (sysctl (mib, 2, &ps_strings, &len, NULL, 0) == 0)
+      {
+	i386bsd_sigtramp_start = ps_strings - 128;
+	i386bsd_sigtramp_end = ps_strings;
+      }
+  }
+#endif
+}

gdb/i386bsd-tdep.c

@@ -0,0 +1,84 @@
+/* Target-dependent code for i386 BSD's.
+   Copyright 2001 Free Software Foundation, Inc.
+
+   This file is part of GDB.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 2 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software
+   Foundation, Inc., 59 Temple Place - Suite 330,
+   Boston, MA 02111-1307, USA.  */
+
+#include "defs.h"
+#include "frame.h"
+#include "gdbcore.h"
+#include "regcache.h"
+
+/* Support for signal handlers.  */
+
+/* Range in which to find the signaltramp routine, traditionally found
+   on the use stack, just below the user area.  Initialized to values
+   that work for NetBSD and FreeBSD.  */
+
+CORE_ADDR i386bsd_sigtramp_start = 0xbfbfdf20;
+CORE_ADDR i386bsd_sigtramp_end = 0xbfbfdff0;
+
+/* Return whether PC is in a BSD sigtramp routine.  */
+
+int
+i386bsd_in_sigtramp (CORE_ADDR pc, char *name)
+{
+  return (pc >= i386bsd_sigtramp_start && pc < i386bsd_sigtramp_end);
+}
+
+/* Offset in the sigcontext structure of the program counter.
+   Initialized to the value from 4.4 BSD Lite.  */
+int i386bsd_sigcontext_pc_offset = 20;
+
+/* Assuming FRAME is for a BSD sigtramp routine, return the address of
+   the associated sigcontext structure.  */
+
+static CORE_ADDR
+i386bsd_sigcontext_addr (struct frame_info *frame)
+{
+  if (frame->next)
+    /* If this isn't the top frame, the next frame must be for the
+       signal handler itself.  A pointer to the sigcontext structure
+       is passed as the third argument to the signal handler.  */
+    return read_memory_unsigned_integer (frame->next->frame + 16, 4);
+
+  /* This is the top frame.  We'll have to find the address of the
+     sigcontext structure by looking at the stack pointer.  */
+  return read_memory_unsigned_integer (read_register (SP_REGNUM) + 8, 4);
+}
+
+/* Assuming FRAME is for a BSD sigtramp routine, return the saved
+   program counter.  */
+
+static CORE_ADDR
+i386bsd_sigtramp_saved_pc (struct frame_info *frame)
+{
+  CORE_ADDR addr;
+  addr = i386bsd_sigcontext_addr (frame);
+  return read_memory_unsigned_integer (addr + i386bsd_sigcontext_pc_offset, 4);
+}
+
+/* Return the saved program counter for FRAME.  */
+
+CORE_ADDR
+i386bsd_frame_saved_pc (struct frame_info *frame)
+{
+  if (frame->signal_handler_caller)
+    return i386bsd_sigtramp_saved_pc (frame);
+
+  return read_memory_unsigned_integer (frame->frame + 4, 4);
+}