Initial revision

1 files changed, 1690 insertions, 0 deletions

diff --git a/gdb/infrun.c b/gdb/infrun.c
new file mode 100644
index 0000000..1cca592
--- /dev/null
+++ b/gdb/infrun.c
@@ -0,0 +1,1690 @@
+/* Start (run) and stop the inferior process, for GDB.
+   Copyright (C) 1986, 1987, 1988, 1989, 1991 Free Software Foundation, Inc.
+
+This file is part of GDB.
+
+GDB 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 1, or (at your option)
+any later version.
+
+GDB 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 GDB; see the file COPYING.  If not, write to
+the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.  */
+
+/* Notes on the algorithm used in wait_for_inferior to determine if we
+   just did a subroutine call when stepping.  We have the following
+   information at that point:
+
+                  Current and previous (just before this step) pc.
+		  Current and previous sp.
+		  Current and previous start of current function.
+
+   If the start's of the functions don't match, then
+
+   	a) We did a subroutine call.
+
+   In this case, the pc will be at the beginning of a function.
+
+	b) We did a subroutine return.
+
+   Otherwise.
+
+	c) We did a longjmp.
+
+   If we did a longjump, we were doing "nexti", since a next would
+   have attempted to skip over the assembly language routine in which
+   the longjmp is coded and would have simply been the equivalent of a
+   continue.  I consider this ok behaivior.  We'd like one of two
+   things to happen if we are doing a nexti through the longjmp()
+   routine: 1) It behaves as a stepi, or 2) It acts like a continue as
+   above.  Given that this is a special case, and that anybody who
+   thinks that the concept of sub calls is meaningful in the context
+   of a longjmp, I'll take either one.  Let's see what happens.  
+
+   Acts like a subroutine return.  I can handle that with no problem
+   at all.
+
+   -->So: If the current and previous beginnings of the current
+   function don't match, *and* the pc is at the start of a function,
+   we've done a subroutine call.  If the pc is not at the start of a
+   function, we *didn't* do a subroutine call.  
+
+   -->If the beginnings of the current and previous function do match,
+   either: 
+
+   	a) We just did a recursive call.
+
+	   In this case, we would be at the very beginning of a
+	   function and 1) it will have a prologue (don't jump to
+	   before prologue, or 2) (we assume here that it doesn't have
+	   a prologue) there will have been a change in the stack
+	   pointer over the last instruction.  (Ie. it's got to put
+	   the saved pc somewhere.  The stack is the usual place.  In
+	   a recursive call a register is only an option if there's a
+	   prologue to do something with it.  This is even true on
+	   register window machines; the prologue sets up the new
+	   window.  It might not be true on a register window machine
+	   where the call instruction moved the register window
+	   itself.  Hmmm.  One would hope that the stack pointer would
+	   also change.  If it doesn't, somebody send me a note, and
+	   I'll work out a more general theory.
+	   bug-gdb@prep.ai.mit.edu).  This is true (albeit slipperly
+	   so) on all machines I'm aware of:
+
+	      m68k:	Call changes stack pointer.  Regular jumps don't.
+
+	      sparc:	Recursive calls must have frames and therefor,
+	                prologues.
+
+	      vax:	All calls have frames and hence change the
+	                stack pointer.
+
+	b) We did a return from a recursive call.  I don't see that we
+	   have either the ability or the need to distinguish this
+	   from an ordinary jump.  The stack frame will be printed
+	   when and if the frame pointer changes; if we are in a
+	   function without a frame pointer, it's the users own
+	   lookout.
+
+	c) We did a jump within a function.  We assume that this is
+	   true if we didn't do a recursive call.
+
+	d) We are in no-man's land ("I see no symbols here").  We
+	   don't worry about this; it will make calls look like simple
+	   jumps (and the stack frames will be printed when the frame
+	   pointer moves), which is a reasonably non-violent response.
+
+#if 0
+    We skip this; it causes more problems than it's worth.
+#ifdef SUN4_COMPILER_FEATURE
+    We do a special ifdef for the sun 4, forcing it to single step
+  into calls which don't have prologues.  This means that we can't
+  nexti over leaf nodes, we can probably next over them (since they
+  won't have debugging symbols, usually), and we can next out of
+  functions returning structures (with a "call .stret4" at the end).
+#endif
+#endif
+*/
+   
+
+   
+   
+
+#include <stdio.h>
+#include <string.h>
+#include "defs.h"
+#include "param.h"
+#include "symtab.h"
+#include "frame.h"
+#include "inferior.h"
+#include "breakpoint.h"
+#include "wait.h"
+#include "gdbcore.h"
+#include "signame.h"
+#include "command.h"
+#include "terminal.h"		/* For #ifdef TIOCGPGRP and new_tty */
+#include "target.h"
+
+#include <signal.h>
+
+/* unistd.h is needed to #define X_OK */
+#ifdef USG
+#include <unistd.h>
+#else
+#include <sys/file.h>
+#endif
+
+#ifdef SET_STACK_LIMIT_HUGE
+extern int original_stack_limit;
+#endif /* SET_STACK_LIMIT_HUGE */
+
+/* Required by <sys/user.h>.  */
+#include <sys/types.h>
+/* Required by <sys/user.h>, at least on system V.  */
+#include <sys/dir.h>
+/* Needed by IN_SIGTRAMP on some machines (e.g. vax).  */
+#include <sys/param.h>
+/* Needed by IN_SIGTRAMP on some machines (e.g. vax).  */
+#include <sys/user.h>
+
+extern char *getenv ();
+
+extern struct target_ops child_ops;	/* In inftarg.c */
+
+/* Copy of inferior_io_terminal when inferior was last started.  */
+
+extern char *inferior_thisrun_terminal;
+
+
+/* Sigtramp is a routine that the kernel calls (which then calls the
+   signal handler).  On most machines it is a library routine that
+   is linked into the executable.
+
+   This macro, given a program counter value and the name of the
+   function in which that PC resides (which can be null if the
+   name is not known), returns nonzero if the PC and name show
+   that we are in sigtramp.
+
+   On most machines just see if the name is sigtramp (and if we have
+   no name, assume we are not in sigtramp).  */
+#if !defined (IN_SIGTRAMP)
+#define IN_SIGTRAMP(pc, name) \
+  name && !strcmp ("_sigtramp", name)
+#endif
+
+/* Tables of how to react to signals; the user sets them.  */
+
+static char signal_stop[NSIG];
+static char signal_print[NSIG];
+static char signal_program[NSIG];
+
+/* Nonzero if breakpoints are now inserted in the inferior.  */
+/* Nonstatic for initialization during xxx_create_inferior. FIXME. */
+
+/*static*/ int breakpoints_inserted;
+
+/* Function inferior was in as of last step command.  */
+
+static struct symbol *step_start_function;
+
+/* Nonzero => address for special breakpoint for resuming stepping.  */
+
+static CORE_ADDR step_resume_break_address;
+
+/* Pointer to orig contents of the byte where the special breakpoint is.  */
+
+static char step_resume_break_shadow[BREAKPOINT_MAX];
+
+/* Nonzero means the special breakpoint is a duplicate
+   so it has not itself been inserted.  */
+
+static int step_resume_break_duplicate;
+
+/* Nonzero if we are expecting a trace trap and should proceed from it.  */
+
+static int trap_expected;
+
+/* Nonzero if the next time we try to continue the inferior, it will
+   step one instruction and generate a spurious trace trap.
+   This is used to compensate for a bug in HP-UX.  */
+
+static int trap_expected_after_continue;
+
+/* Nonzero means expecting a trace trap
+   and should stop the inferior and return silently when it happens.  */
+
+int stop_after_trap;
+
+/* Nonzero means expecting a trap and caller will handle it themselves.
+   It is used after attach, due to attaching to a process;
+   when running in the shell before the child program has been exec'd;
+   and when running some kinds of remote stuff (FIXME?).  */
+
+int stop_soon_quietly;
+
+/* Nonzero if pc has been changed by the debugger
+   since the inferior stopped.  */
+
+int pc_changed;
+
+/* Nonzero if proceed is being used for a "finish" command or a similar
+   situation when stop_registers should be saved.  */
+
+int proceed_to_finish;
+
+/* Save register contents here when about to pop a stack dummy frame,
+   if-and-only-if proceed_to_finish is set.
+   Thus this contains the return value from the called function (assuming
+   values are returned in a register).  */
+
+char stop_registers[REGISTER_BYTES];
+
+/* Nonzero if program stopped due to error trying to insert breakpoints.  */
+
+static int breakpoints_failed;
+
+/* Nonzero after stop if current stack frame should be printed.  */
+
+static int stop_print_frame;
+
+#ifdef NO_SINGLE_STEP
+extern int one_stepped;		/* From machine dependent code */
+extern void single_step ();	/* Same. */
+#endif /* NO_SINGLE_STEP */
+
+static void insert_step_breakpoint ();
+static void remove_step_breakpoint ();
+/*static*/ void wait_for_inferior ();
+void init_wait_for_inferior ();
+void normal_stop ();
+
+
+/* Clear out all variables saying what to do when inferior is continued.
+   First do this, then set the ones you want, then call `proceed'.  */
+
+void
+clear_proceed_status ()
+{
+  trap_expected = 0;
+  step_range_start = 0;
+  step_range_end = 0;
+  step_frame_address = 0;
+  step_over_calls = -1;
+  step_resume_break_address = 0;
+  stop_after_trap = 0;
+  stop_soon_quietly = 0;
+  proceed_to_finish = 0;
+  breakpoint_proceeded = 1;	/* We're about to proceed... */
+
+  /* Discard any remaining commands or status from previous stop.  */
+  bpstat_clear (&stop_bpstat);
+}
+
+/* Basic routine for continuing the program in various fashions.
+
+   ADDR is the address to resume at, or -1 for resume where stopped.
+   SIGGNAL is the signal to give it, or 0 for none,
+     or -1 for act according to how it stopped.
+   STEP is nonzero if should trap after one instruction.
+     -1 means return after that and print nothing.
+     You should probably set various step_... variables
+     before calling here, if you are stepping.
+
+   You should call clear_proceed_status before calling proceed.  */
+
+void
+proceed (addr, siggnal, step)
+     CORE_ADDR addr;
+     int siggnal;
+     int step;
+{
+  int oneproc = 0;
+
+  if (step > 0)
+    step_start_function = find_pc_function (read_pc ());
+  if (step < 0)
+    stop_after_trap = 1;
+
+  if (addr == -1)
+    {
+      /* If there is a breakpoint at the address we will resume at,
+	 step one instruction before inserting breakpoints
+	 so that we do not stop right away.  */
+
+      if (!pc_changed && breakpoint_here_p (read_pc ()))
+	oneproc = 1;
+    }
+  else
+    {
+      write_register (PC_REGNUM, addr);
+#ifdef NPC_REGNUM
+      write_register (NPC_REGNUM, addr + 4);
+#ifdef NNPC_REGNUM
+      write_register (NNPC_REGNUM, addr + 8);
+#endif
+#endif
+    }
+
+  if (trap_expected_after_continue)
+    {
+      /* If (step == 0), a trap will be automatically generated after
+	 the first instruction is executed.  Force step one
+	 instruction to clear this condition.  This should not occur
+	 if step is nonzero, but it is harmless in that case.  */
+      oneproc = 1;
+      trap_expected_after_continue = 0;
+    }
+
+  if (oneproc)
+    /* We will get a trace trap after one instruction.
+       Continue it automatically and insert breakpoints then.  */
+    trap_expected = 1;
+  else
+    {
+      int temp = insert_breakpoints ();
+      if (temp)
+	{
+	  print_sys_errmsg ("ptrace", temp);
+	  error ("Cannot insert breakpoints.\n\
+The same program may be running in another process.");
+	}
+      breakpoints_inserted = 1;
+    }
+
+  /* Install inferior's terminal modes.  */
+  target_terminal_inferior ();
+
+  if (siggnal >= 0)
+    stop_signal = siggnal;
+  /* If this signal should not be seen by program,
+     give it zero.  Used for debugging signals.  */
+  else if (stop_signal < NSIG && !signal_program[stop_signal])
+    stop_signal= 0;
+
+  /* Handle any optimized stores to the inferior NOW...  */
+#ifdef DO_DEFERRED_STORES
+  DO_DEFERRED_STORES;
+#endif
+
+  /* Resume inferior.  */
+  target_resume (oneproc || step || bpstat_should_step (), stop_signal);
+
+  /* Wait for it to stop (if not standalone)
+     and in any case decode why it stopped, and act accordingly.  */
+
+  wait_for_inferior ();
+  normal_stop ();
+}
+
+#if 0
+/* This might be useful (not sure), but isn't currently used.  See also
+   write_pc().  */
+/* Writing the inferior pc as a register calls this function
+   to inform infrun that the pc has been set in the debugger.  */
+
+void
+writing_pc (val)
+     CORE_ADDR val;
+{
+  stop_pc = val;
+  pc_changed = 1;
+}
+#endif
+
+/* Record the pc and sp of the program the last time it stopped.
+   These are just used internally by wait_for_inferior, but need
+   to be preserved over calls to it and cleared when the inferior
+   is started.  */
+static CORE_ADDR prev_pc;
+static CORE_ADDR prev_sp;
+static CORE_ADDR prev_func_start;
+static char *prev_func_name;
+
+/* Start an inferior Unix child process and sets inferior_pid to its pid.
+   EXEC_FILE is the file to run.
+   ALLARGS is a string containing the arguments to the program.
+   ENV is the environment vector to pass.  Errors reported with error().  */
+
+#ifndef SHELL_FILE
+#define SHELL_FILE "/bin/sh"
+#endif
+
+void
+child_create_inferior (exec_file, allargs, env)
+     char *exec_file;
+     char *allargs;
+     char **env;
+{
+  int pid;
+  char *shell_command;
+  extern int sys_nerr;
+  extern char *sys_errlist[];
+  char *shell_file;
+  static char default_shell_file[] = SHELL_FILE;
+  int len;
+  int pending_execs;
+  /* Set debug_fork then attach to the child while it sleeps, to debug. */
+  static int debug_fork = 0;
+  /* This is set to the result of setpgrp, which if vforked, will be visible
+     to you in the parent process.  It's only used by humans for debugging.  */
+  static int debug_setpgrp = 657473;
+
+  /* The user might want tilde-expansion, and in general probably wants
+     the program to behave the same way as if run from
+     his/her favorite shell.  So we let the shell run it for us.
+     FIXME, this should probably search the local environment (as
+     modified by the setenv command), not the env gdb inherited.  */
+  shell_file = getenv ("SHELL");
+  if (shell_file == NULL)
+    shell_file = default_shell_file;
+  
+  len = 5 + strlen (exec_file) + 1 + strlen (allargs) + 1 + /*slop*/ 10;
+  /* If desired, concat something onto the front of ALLARGS.
+     SHELL_COMMAND is the result.  */
+#ifdef SHELL_COMMAND_CONCAT
+  shell_command = (char *) alloca (strlen (SHELL_COMMAND_CONCAT) + len);
+  strcpy (shell_command, SHELL_COMMAND_CONCAT);
+#else
+  shell_command = (char *) alloca (len);
+  shell_command[0] = '\0';
+#endif
+  strcat (shell_command, "exec ");
+  strcat (shell_command, exec_file);
+  strcat (shell_command, " ");
+  strcat (shell_command, allargs);
+
+  /* exec is said to fail if the executable is open.  */
+  close_exec_file ();
+
+#if defined(USG) && !defined(HAVE_VFORK)
+  pid = fork ();
+#else
+  if (debug_fork)
+    pid = fork ();
+  else
+    pid = vfork ();
+#endif
+
+  if (pid < 0)
+    perror_with_name ("vfork");
+
+  if (pid == 0)
+    {
+      if (debug_fork) 
+	sleep (debug_fork);
+
+#ifdef TIOCGPGRP
+      /* Run inferior in a separate process group.  */
+      debug_setpgrp = setpgrp (getpid (), getpid ());
+      if (0 != debug_setpgrp)
+	 perror("setpgrp failed in child");
+#endif /* TIOCGPGRP */
+
+#ifdef SET_STACK_LIMIT_HUGE
+      /* Reset the stack limit back to what it was.  */
+      {
+	struct rlimit rlim;
+
+	getrlimit (RLIMIT_STACK, &rlim);
+	rlim.rlim_cur = original_stack_limit;
+	setrlimit (RLIMIT_STACK, &rlim);
+      }
+#endif /* SET_STACK_LIMIT_HUGE */
+
+      /* Tell the terminal handling subsystem what tty we plan to run on;
+	 it will now switch to that one if non-null.  */
+
+      new_tty (inferior_io_terminal);
+
+      /* Changing the signal handlers for the inferior after
+	 a vfork can also change them for the superior, so we don't mess
+	 with signals here.  See comments in
+	 initialize_signals for how we get the right signal handlers
+	 for the inferior.  */
+
+      call_ptrace (0, 0, 0, 0);		/* "Trace me, Dr. Memory!" */
+      execle (shell_file, shell_file, "-c", shell_command, (char *)0, env);
+
+      fprintf (stderr, "Cannot exec %s: %s.\n", shell_file,
+	       errno < sys_nerr ? sys_errlist[errno] : "unknown error");
+      fflush (stderr);
+      _exit (0177);
+    }
+
+  /* Now that we have a child process, make it our target.  */
+  push_target (&child_ops);
+
+#ifdef CREATE_INFERIOR_HOOK
+  CREATE_INFERIOR_HOOK (pid);
+#endif  
+
+/* The process was started by the fork that created it,
+   but it will have stopped one instruction after execing the shell.
+   Here we must get it up to actual execution of the real program.  */
+
+  inferior_pid = pid;		/* Needed for wait_for_inferior stuff below */
+
+  clear_proceed_status ();
+
+#if defined (START_INFERIOR_HOOK)
+  START_INFERIOR_HOOK ();
+#endif
+
+  /* We will get a trace trap after one instruction.
+     Continue it automatically.  Eventually (after shell does an exec)
+     it will get another trace trap.  Then insert breakpoints and continue.  */
+
+#ifdef START_INFERIOR_TRAPS_EXPECTED
+  pending_execs = START_INFERIOR_TRAPS_EXPECTED;
+#else
+  pending_execs = 2;
+#endif
+
+  init_wait_for_inferior ();
+
+  /* Set up the "saved terminal modes" of the inferior
+     based on what modes we are starting it with.  */
+  target_terminal_init ();
+
+  /* Install inferior's terminal modes.  */
+  target_terminal_inferior ();
+
+  while (1)
+    {
+      stop_soon_quietly = 1;	/* Make wait_for_inferior be quiet */
+      wait_for_inferior ();
+      if (stop_signal != SIGTRAP)
+	{
+	  /* Let shell child handle its own signals in its own way */
+	  /* FIXME, what if child has exit()ed?  Must exit loop somehow */
+	  target_resume (0, stop_signal);
+	}
+      else
+	{
+	  /* We handle SIGTRAP, however; it means child did an exec.  */
+	  if (0 == --pending_execs)
+	    break;
+	  target_resume (0, 0);		/* Just make it go on */
+	}
+    }
+  stop_soon_quietly = 0;
+
+  /* Should this perhaps just be a "proceed" call?  FIXME */
+  insert_step_breakpoint ();
+  breakpoints_failed = insert_breakpoints ();
+  if (!breakpoints_failed)
+    {
+      breakpoints_inserted = 1;
+      target_terminal_inferior();
+      /* Start the child program going on its first instruction, single-
+	 stepping if we need to.  */
+      target_resume (bpstat_should_step (), 0);
+      wait_for_inferior ();
+      normal_stop ();
+    }
+}
+
+/* Start remote-debugging of a machine over a serial link.  */
+
+void
+start_remote ()
+{
+  init_wait_for_inferior ();
+  clear_proceed_status ();
+  stop_soon_quietly = 1;
+  trap_expected = 0;
+}
+
+/* Initialize static vars when a new inferior begins.  */
+
+void
+init_wait_for_inferior ()
+{
+  /* These are meaningless until the first time through wait_for_inferior.  */
+  prev_pc = 0;
+  prev_sp = 0;
+  prev_func_start = 0;
+  prev_func_name = NULL;
+
+  trap_expected_after_continue = 0;
+  breakpoints_inserted = 0;
+  mark_breakpoints_out ();
+  stop_signal = 0;		/* Don't confuse first call to proceed(). */
+}
+
+
+/* Attach to process PID, then initialize for debugging it
+   and wait for the trace-trap that results from attaching.  */
+
+void
+child_attach (args, from_tty)
+     char *args;
+     int from_tty;
+{
+  char *exec_file;
+  int pid;
+
+  dont_repeat();
+
+  if (!args)
+    error_no_arg ("process-id to attach");
+
+#ifndef ATTACH_DETACH
+  error ("Can't attach to a process on this machine.");
+#else
+  pid = atoi (args);
+
+  if (target_has_execution)
+    {
+      if (query ("A program is being debugged already.  Kill it? "))
+	target_kill ((char *)0, from_tty);
+      else
+	error ("Inferior not killed.");
+    }
+
+  exec_file = (char *) get_exec_file (1);
+
+  if (from_tty)
+    {
+      printf ("Attaching program: %s pid %d\n",
+	      exec_file, pid);
+      fflush (stdout);
+    }
+
+  attach (pid);
+  inferior_pid = pid;
+  push_target (&child_ops);
+
+  mark_breakpoints_out ();
+  target_terminal_init ();
+  clear_proceed_status ();
+  stop_soon_quietly = 1;
+  /*proceed (-1, 0, -2);*/
+  target_terminal_inferior ();
+  wait_for_inferior ();
+  normal_stop ();
+#endif  /* ATTACH_DETACH */
+}
+
+/* Wait for control to return from inferior to debugger.
+   If inferior gets a signal, we may decide to start it up again
+   instead of returning.  That is why there is a loop in this function.
+   When this function actually returns it means the inferior
+   should be left stopped and GDB should read more commands.  */
+
+void
+wait_for_inferior ()
+{
+  WAITTYPE w;
+  int another_trap;
+  int random_signal;
+  CORE_ADDR stop_sp;
+  CORE_ADDR stop_func_start;
+  char *stop_func_name;
+  CORE_ADDR prologue_pc;
+  int stop_step_resume_break;
+  struct symtab_and_line sal;
+  int remove_breakpoints_on_following_step = 0;
+
+#if 0
+  /* This no longer works now that read_register is lazy;
+     it might try to ptrace when the process is not stopped.  */
+  prev_pc = read_pc ();
+  (void) find_pc_partial_function (prev_pc, &prev_func_name,
+				   &prev_func_start);
+  prev_func_start += FUNCTION_START_OFFSET;
+  prev_sp = read_register (SP_REGNUM);
+#endif /* 0 */
+
+  while (1)
+    {
+      /* Clean up saved state that will become invalid.  */
+      pc_changed = 0;
+      flush_cached_frames ();
+      registers_changed ();
+
+      target_wait (&w);
+
+      /* See if the process still exists; clean up if it doesn't.  */
+      if (WIFEXITED (w))
+	{
+	  target_terminal_ours ();	/* Must do this before mourn anyway */
+	  if (WEXITSTATUS (w))
+	    printf ("\nProgram exited with code 0%o.\n", 
+		     (unsigned int)WEXITSTATUS (w));
+	  else
+	    if (!batch_mode())
+	      printf ("\nProgram exited normally.\n");
+	  fflush (stdout);
+	  target_mourn_inferior ();
+#ifdef NO_SINGLE_STEP
+	  one_stepped = 0;
+#endif
+	  stop_print_frame = 0;
+	  break;
+	}
+      else if (!WIFSTOPPED (w))
+	{
+	  stop_print_frame = 0;
+	  stop_signal = WTERMSIG (w);
+	  target_terminal_ours ();	/* Must do this before mourn anyway */
+	  target_kill ((char *)0, 0);	/* kill mourns as well */
+#ifdef PRINT_RANDOM_SIGNAL
+	  printf ("\nProgram terminated: ");
+	  PRINT_RANDOM_SIGNAL (stop_signal);
+#else
+	  printf ("\nProgram terminated with signal %d, %s\n",
+		  stop_signal,
+		  stop_signal < NSIG
+		  ? sys_siglist[stop_signal]
+		  : "(undocumented)");
+#endif
+	  printf ("The inferior process no longer exists.\n");
+	  fflush (stdout);
+#ifdef NO_SINGLE_STEP
+	  one_stepped = 0;
+#endif
+	  break;
+	}
+      
+#ifdef NO_SINGLE_STEP
+      if (one_stepped)
+	single_step (0);	/* This actually cleans up the ss */
+#endif /* NO_SINGLE_STEP */
+      
+      stop_pc = read_pc ();
+      set_current_frame ( create_new_frame (read_register (FP_REGNUM),
+					    read_pc ()));
+      
+      stop_frame_address = FRAME_FP (get_current_frame ());
+      stop_sp = read_register (SP_REGNUM);
+      stop_func_start = 0;
+      stop_func_name = 0;
+      /* Don't care about return value; stop_func_start and stop_func_name
+	 will both be 0 if it doesn't work.  */
+      (void) find_pc_partial_function (stop_pc, &stop_func_name,
+				       &stop_func_start);
+      stop_func_start += FUNCTION_START_OFFSET;
+      another_trap = 0;
+      bpstat_clear (&stop_bpstat);
+      stop_step = 0;
+      stop_stack_dummy = 0;
+      stop_print_frame = 1;
+      stop_step_resume_break = 0;
+      random_signal = 0;
+      stopped_by_random_signal = 0;
+      breakpoints_failed = 0;
+      
+      /* Look at the cause of the stop, and decide what to do.
+	 The alternatives are:
+	 1) break; to really stop and return to the debugger,
+	 2) drop through to start up again
+	 (set another_trap to 1 to single step once)
+	 3) set random_signal to 1, and the decision between 1 and 2
+	 will be made according to the signal handling tables.  */
+      
+      stop_signal = WSTOPSIG (w);
+      
+      /* First, distinguish signals caused by the debugger from signals
+	 that have to do with the program's own actions.
+	 Note that breakpoint insns may cause SIGTRAP or SIGILL
+	 or SIGEMT, depending on the operating system version.
+	 Here we detect when a SIGILL or SIGEMT is really a breakpoint
+	 and change it to SIGTRAP.  */
+      
+      if (stop_signal == SIGTRAP
+	  || (breakpoints_inserted &&
+	      (stop_signal == SIGILL
+	       || stop_signal == SIGEMT))
+	  || stop_soon_quietly)
+	{
+	  if (stop_signal == SIGTRAP && stop_after_trap)
+	    {
+	      stop_print_frame = 0;
+	      break;
+	    }
+	  if (stop_soon_quietly)
+	    break;
+
+	  /* Don't even think about breakpoints
+	     if just proceeded over a breakpoint.
+
+	     However, if we are trying to proceed over a breakpoint
+	     and end up in sigtramp, then step_resume_break_address
+	     will be set and we should check whether we've hit the
+	     step breakpoint.  */
+	  if (stop_signal == SIGTRAP && trap_expected
+	      && step_resume_break_address == NULL)
+	    bpstat_clear (&stop_bpstat);
+	  else
+	    {
+	      /* See if there is a breakpoint at the current PC.  */
+#if DECR_PC_AFTER_BREAK
+	      /* Notice the case of stepping through a jump
+		 that leads just after a breakpoint.
+		 Don't confuse that with hitting the breakpoint.
+		 What we check for is that 1) stepping is going on
+		 and 2) the pc before the last insn does not match
+		 the address of the breakpoint before the current pc.  */
+	      if (!(prev_pc != stop_pc - DECR_PC_AFTER_BREAK
+		    && step_range_end && !step_resume_break_address))
+#endif /* DECR_PC_AFTER_BREAK not zero */
+		{
+		  /* See if we stopped at the special breakpoint for
+		     stepping over a subroutine call.  If both are zero,
+		     this wasn't the reason for the stop.  */
+		  if (stop_pc - DECR_PC_AFTER_BREAK
+		      		  == step_resume_break_address
+		      && step_resume_break_address)
+		    {
+		      stop_step_resume_break = 1;
+		      if (DECR_PC_AFTER_BREAK)
+			{
+			  stop_pc -= DECR_PC_AFTER_BREAK;
+			  write_register (PC_REGNUM, stop_pc);
+			  pc_changed = 0;
+			}
+		    }
+		  else
+		    {
+		      stop_bpstat =
+			bpstat_stop_status (&stop_pc, stop_frame_address);
+		      /* Following in case break condition called a
+			 function.  */
+		      stop_print_frame = 1;
+		    }
+		}
+	    }
+	  
+	  if (stop_signal == SIGTRAP)
+	    random_signal
+	      = !(bpstat_explains_signal (stop_bpstat)
+		  || trap_expected
+		  || stop_step_resume_break
+		  || PC_IN_CALL_DUMMY (stop_pc, stop_sp, stop_frame_address)
+		  || (step_range_end && !step_resume_break_address));
+	  else
+	    {
+	      random_signal
+		= !(bpstat_explains_signal (stop_bpstat)
+		    || stop_step_resume_break
+		    /* End of a stack dummy.  Some systems (e.g. Sony
+		       news) give another signal besides SIGTRAP,
+		       so check here as well as above.  */
+		    || (stop_sp INNER_THAN stop_pc
+			&& stop_pc INNER_THAN stop_frame_address)
+		    );
+	      if (!random_signal)
+		stop_signal = SIGTRAP;
+	    }
+	}
+      else
+	random_signal = 1;
+      
+      /* For the program's own signals, act according to
+	 the signal handling tables.  */
+      
+      if (random_signal)
+	{
+	  /* Signal not for debugging purposes.  */
+	  int printed = 0;
+	  
+	  stopped_by_random_signal = 1;
+	  
+	  if (stop_signal >= NSIG
+	      || signal_print[stop_signal])
+	    {
+	      printed = 1;
+	      target_terminal_ours_for_output ();
+#ifdef PRINT_RANDOM_SIGNAL
+	      PRINT_RANDOM_SIGNAL (stop_signal);
+#else
+	      printf ("\nProgram received signal %d, %s\n",
+		      stop_signal,
+		      stop_signal < NSIG
+		      ? sys_siglist[stop_signal]
+		      : "(undocumented)");
+#endif /* PRINT_RANDOM_SIGNAL */
+	      fflush (stdout);
+	    }
+	  if (stop_signal >= NSIG
+	      || signal_stop[stop_signal])
+	    break;
+	  /* If not going to stop, give terminal back
+	     if we took it away.  */
+	  else if (printed)
+	    target_terminal_inferior ();
+	}
+      
+      /* Handle cases caused by hitting a breakpoint.  */
+      
+      if (!random_signal
+	  && (bpstat_explains_signal (stop_bpstat) || stop_step_resume_break))
+	{
+	  /* Does a breakpoint want us to stop?  */
+	  if (bpstat_stop (stop_bpstat))
+	    {
+	      stop_print_frame = bpstat_should_print (stop_bpstat);
+	      break;
+	    }
+	  /* But if we have hit the step-resumption breakpoint,
+	     remove it.  It has done its job getting us here.
+	     The sp test is to make sure that we don't get hung
+	     up in recursive calls in functions without frame
+	     pointers.  If the stack pointer isn't outside of
+	     where the breakpoint was set (within a routine to be
+	     stepped over), we're in the middle of a recursive
+	     call. Not true for reg window machines (sparc)
+	     because the must change frames to call things and
+	     the stack pointer doesn't have to change if it
+	     the bp was set in a routine without a frame (pc can
+	     be stored in some other window).
+	     
+	     The removal of the sp test is to allow calls to
+	     alloca.  Nasty things were happening.  Oh, well,
+	     gdb can only handle one level deep of lack of
+	     frame pointer. */
+	  if (stop_step_resume_break
+	      && (step_frame_address == 0
+		  || (stop_frame_address == step_frame_address)))
+	    {
+	      remove_step_breakpoint ();
+	      step_resume_break_address = 0;
+
+	      /* If were waiting for a trap, hitting the step_resume_break
+		 doesn't count as getting it.  */
+	      if (trap_expected)
+		another_trap = 1;
+	    }
+	  /* Otherwise, must remove breakpoints and single-step
+	     to get us past the one we hit.  */
+	  else
+	    {
+	      remove_breakpoints ();
+	      remove_step_breakpoint ();
+	      breakpoints_inserted = 0;
+	      another_trap = 1;
+	    }
+	  
+	  /* We come here if we hit a breakpoint but should not
+	     stop for it.  Possibly we also were stepping
+	     and should stop for that.  So fall through and
+	     test for stepping.  But, if not stepping,
+	     do not stop.  */
+	}
+      
+      /* If this is the breakpoint at the end of a stack dummy,
+	 just stop silently.  */
+      if (PC_IN_CALL_DUMMY (stop_pc, stop_sp, stop_frame_address))
+	  {
+	    stop_print_frame = 0;
+	    stop_stack_dummy = 1;
+#ifdef HP_OS_BUG
+	    trap_expected_after_continue = 1;
+#endif
+	    break;
+	  }
+      
+      if (step_resume_break_address)
+	/* Having a step-resume breakpoint overrides anything
+	   else having to do with stepping commands until
+	   that breakpoint is reached.  */
+	;
+      /* If stepping through a line, keep going if still within it.  */
+      else if (!random_signal
+	       && step_range_end
+	       && stop_pc >= step_range_start
+	       && stop_pc < step_range_end
+	       /* The step range might include the start of the
+		  function, so if we are at the start of the
+		  step range and either the stack or frame pointers
+		  just changed, we've stepped outside */
+	       && !(stop_pc == step_range_start
+		    && stop_frame_address
+		    && (stop_sp INNER_THAN prev_sp
+			|| stop_frame_address != step_frame_address)))
+	{
+#if 0
+	  /* When "next"ing through a function,
+	     This causes an extra stop at the end.
+	     Is there any reason for this?
+	     It's confusing to the user.  */
+	  /* Don't step through the return from a function
+	     unless that is the first instruction stepped through.  */
+	  if (ABOUT_TO_RETURN (stop_pc))
+	    {
+	      stop_step = 1;
+	      break;
+	    }
+#endif
+	}
+      
+      /* We stepped out of the stepping range.  See if that was due
+	 to a subroutine call that we should proceed to the end of.  */
+      else if (!random_signal && step_range_end)
+	{
+	  if (stop_func_start)
+	    {
+	      prologue_pc = stop_func_start;
+	      SKIP_PROLOGUE (prologue_pc);
+	    }
+
+	  /* Did we just take a signal?  */
+	  if (IN_SIGTRAMP (stop_pc, stop_func_name)
+	      && !IN_SIGTRAMP (prev_pc, prev_func_name))
+	    {
+	      /* This code is needed at least in the following case:
+		 The user types "next" and then a signal arrives (before
+		 the "next" is done).  */
+	      /* We've just taken a signal; go until we are back to
+		 the point where we took it and one more.  */
+	      step_resume_break_address = prev_pc;
+	      step_resume_break_duplicate =
+		breakpoint_here_p (step_resume_break_address);
+	      if (breakpoints_inserted)
+		insert_step_breakpoint ();
+	      /* Make sure that the stepping range gets us past
+		 that instruction.  */
+	      if (step_range_end == 1)
+		step_range_end = (step_range_start = prev_pc) + 1;
+	      remove_breakpoints_on_following_step = 1;
+	    }
+
+	  /* ==> See comments at top of file on this algorithm.  <==*/
+	  
+	  else if (stop_pc == stop_func_start
+	      && (stop_func_start != prev_func_start
+		  || prologue_pc != stop_func_start
+		  || stop_sp != prev_sp))
+	    {
+	      /* It's a subroutine call */
+	      if (step_over_calls > 0 
+		  || (step_over_calls &&  find_pc_function (stop_pc) == 0))
+		{
+		  /* A subroutine call has happened.  */
+		  /* Set a special breakpoint after the return */
+		  step_resume_break_address =
+		    ADDR_BITS_REMOVE
+		      (SAVED_PC_AFTER_CALL (get_current_frame ()));
+		  step_resume_break_duplicate
+		    = breakpoint_here_p (step_resume_break_address);
+		  if (breakpoints_inserted)
+		    insert_step_breakpoint ();
+		}
+	      /* Subroutine call with source code we should not step over.
+		 Do step to the first line of code in it.  */
+	      else if (step_over_calls)
+		{
+		  SKIP_PROLOGUE (stop_func_start);
+		  sal = find_pc_line (stop_func_start, 0);
+		  /* Use the step_resume_break to step until
+		     the end of the prologue, even if that involves jumps
+		     (as it seems to on the vax under 4.2).  */
+		  /* If the prologue ends in the middle of a source line,
+		     continue to the end of that source line.
+		     Otherwise, just go to end of prologue.  */
+#ifdef PROLOGUE_FIRSTLINE_OVERLAP
+		  /* no, don't either.  It skips any code that's
+		     legitimately on the first line.  */
+#else
+		  if (sal.end && sal.pc != stop_func_start)
+		    stop_func_start = sal.end;
+#endif
+		  
+		  if (stop_func_start == stop_pc)
+		    {
+		      /* We are already there: stop now.  */
+		      stop_step = 1;
+		      break;
+		    }
+		  else
+		    /* Put the step-breakpoint there and go until there. */
+		    {
+		      step_resume_break_address = stop_func_start;
+		      
+		      step_resume_break_duplicate
+			= breakpoint_here_p (step_resume_break_address);
+		      if (breakpoints_inserted)
+			insert_step_breakpoint ();
+		      /* Do not specify what the fp should be when we stop
+			 since on some machines the prologue
+			 is where the new fp value is established.  */
+		      step_frame_address = 0;
+		      /* And make sure stepping stops right away then.  */
+		      step_range_end = step_range_start;
+		    }
+		}
+	      else
+		{
+		  /* We get here only if step_over_calls is 0 and we
+		     just stepped into a subroutine.  I presume
+		     that step_over_calls is only 0 when we're
+		     supposed to be stepping at the assembly
+		     language level.*/
+		  stop_step = 1;
+		  break;
+		}
+	    }
+	  /* No subroutince call; stop now.  */
+	  else
+	    {
+	      stop_step = 1;
+	      break;
+	    }
+	}
+
+      else if (trap_expected
+	       && IN_SIGTRAMP (stop_pc, stop_func_name)
+	       && !IN_SIGTRAMP (prev_pc, prev_func_name))
+	{
+	  /* What has happened here is that we have just stepped the inferior
+	     with a signal (because it is a signal which shouldn't make
+	     us stop), thus stepping into sigtramp.
+
+	     So we need to set a step_resume_break_address breakpoint
+	     and continue until we hit it, and then step.  */
+	  step_resume_break_address = prev_pc;
+	  /* Always 1, I think, but it's probably easier to have
+	     the step_resume_break as usual rather than trying to
+	     re-use the breakpoint which is already there.  */
+	  step_resume_break_duplicate =
+	    breakpoint_here_p (step_resume_break_address);
+	  if (breakpoints_inserted)
+	    insert_step_breakpoint ();
+	  remove_breakpoints_on_following_step = 1;
+	  another_trap = 1;
+	}
+
+      /* Save the pc before execution, to compare with pc after stop.  */
+      prev_pc = read_pc ();	/* Might have been DECR_AFTER_BREAK */
+      prev_func_start = stop_func_start; /* Ok, since if DECR_PC_AFTER
+					  BREAK is defined, the
+					  original pc would not have
+					  been at the start of a
+					  function. */
+      prev_func_name = stop_func_name;
+      prev_sp = stop_sp;
+
+      /* If we did not do break;, it means we should keep
+	 running the inferior and not return to debugger.  */
+
+      if (trap_expected && stop_signal != SIGTRAP)
+	{
+	  /* We took a signal (which we are supposed to pass through to
+	     the inferior, else we'd have done a break above) and we
+	     haven't yet gotten our trap.  Simply continue.  */
+	  target_resume ((step_range_end && !step_resume_break_address)
+		  || (trap_expected && !step_resume_break_address)
+		  || bpstat_should_step (),
+		  stop_signal);
+	}
+      else
+	{
+	  /* Either the trap was not expected, but we are continuing
+	     anyway (the user asked that this signal be passed to the
+	     child)
+	       -- or --
+	     The signal was SIGTRAP, e.g. it was our signal, but we
+	     decided we should resume from it.
+
+	     We're going to run this baby now!
+
+	     Insert breakpoints now, unless we are trying
+	     to one-proceed past a breakpoint.  */
+	  /* If we've just finished a special step resume and we don't
+	     want to hit a breakpoint, pull em out.  */
+	  if (!step_resume_break_address &&
+	      remove_breakpoints_on_following_step)
+	    {
+	      remove_breakpoints_on_following_step = 0;
+	      remove_breakpoints ();
+	      breakpoints_inserted = 0;
+	    }
+	  else if (!breakpoints_inserted &&
+		   (step_resume_break_address != NULL || !another_trap))
+	    {
+	      insert_step_breakpoint ();
+	      breakpoints_failed = insert_breakpoints ();
+	      if (breakpoints_failed)
+		break;
+	      breakpoints_inserted = 1;
+	    }
+
+	  trap_expected = another_trap;
+
+	  if (stop_signal == SIGTRAP)
+	    stop_signal = 0;
+
+#ifdef SHIFT_INST_REGS
+	  /* I'm not sure when this following segment applies.  I do know, now,
+	     that we shouldn't rewrite the regs when we were stopped by a
+	     random signal from the inferior process.  */
+
+          if (!stop_breakpoint && (stop_signal != SIGCLD) 
+              && !stopped_by_random_signal)
+            {
+            CORE_ADDR pc_contents = read_register (PC_REGNUM);
+            CORE_ADDR npc_contents = read_register (NPC_REGNUM);
+            if (pc_contents != npc_contents)
+              {
+              write_register (NNPC_REGNUM, npc_contents);
+              write_register (NPC_REGNUM, pc_contents);
+	      }
+            }
+#endif /* SHIFT_INST_REGS */
+
+	  target_resume ((step_range_end && !step_resume_break_address)
+		  || (trap_expected && !step_resume_break_address)
+		  || bpstat_should_step (),
+		  stop_signal);
+	}
+    }
+  if (target_has_execution)
+    {
+      /* Assuming the inferior still exists, set these up for next
+	 time, just like we did above if we didn't break out of the
+	 loop.  */
+      prev_pc = read_pc ();
+      prev_func_start = stop_func_start;
+      prev_func_name = stop_func_name;
+      prev_sp = stop_sp;
+    }
+}
+
+/* Here to return control to GDB when the inferior stops for real.
+   Print appropriate messages, remove breakpoints, give terminal our modes.
+
+   STOP_PRINT_FRAME nonzero means print the executing frame
+   (pc, function, args, file, line number and line text).
+   BREAKPOINTS_FAILED nonzero means stop was due to error
+   attempting to insert breakpoints.  */
+
+void
+normal_stop ()
+{
+  /* Make sure that the current_frame's pc is correct.  This
+     is a correction for setting up the frame info before doing
+     DECR_PC_AFTER_BREAK */
+  if (target_has_execution)
+    (get_current_frame ())->pc = read_pc ();
+  
+  if (breakpoints_failed)
+    {
+      target_terminal_ours_for_output ();
+      print_sys_errmsg ("ptrace", breakpoints_failed);
+      printf ("Stopped; cannot insert breakpoints.\n\
+The same program may be running in another process.\n");
+    }
+
+  if (target_has_execution)
+    remove_step_breakpoint ();
+
+  if (target_has_execution && breakpoints_inserted)
+    if (remove_breakpoints ())
+      {
+	target_terminal_ours_for_output ();
+	printf ("Cannot remove breakpoints because program is no longer writable.\n\
+It might be running in another process.\n\
+Further execution is probably impossible.\n");
+      }
+
+  breakpoints_inserted = 0;
+
+  /* Delete the breakpoint we stopped at, if it wants to be deleted.
+     Delete any breakpoint that is to be deleted at the next stop.  */
+
+  breakpoint_auto_delete (stop_bpstat);
+
+  /* If an auto-display called a function and that got a signal,
+     delete that auto-display to avoid an infinite recursion.  */
+
+  if (stopped_by_random_signal)
+    disable_current_display ();
+
+  if (step_multi && stop_step)
+    return;
+
+  target_terminal_ours ();
+
+  if (!target_has_stack)
+    return;
+
+  /* Select innermost stack frame except on return from a stack dummy routine,
+     or if the program has exited.  */
+  if (!stop_stack_dummy)
+    {
+      select_frame (get_current_frame (), 0);
+
+      if (stop_print_frame)
+	{
+	  int source_only = bpstat_print (stop_bpstat);
+	  print_sel_frame
+	    (source_only
+	     || (stop_step
+		 && step_frame_address == stop_frame_address
+		 && step_start_function == find_pc_function (stop_pc)));
+
+	  /* Display the auto-display expressions.  */
+	  do_displays ();
+	}
+    }
+
+  /* Save the function value return registers, if we care.
+     We might be about to restore their previous contents.  */
+  if (proceed_to_finish)
+    read_register_bytes (0, stop_registers, REGISTER_BYTES);
+
+  if (stop_stack_dummy)
+    {
+      /* Pop the empty frame that contains the stack dummy.
+         POP_FRAME ends with a setting of the current frame, so we
+	 can use that next. */
+      POP_FRAME;
+      select_frame (get_current_frame (), 0);
+    }
+}
+
+static void
+insert_step_breakpoint ()
+{
+  if (step_resume_break_address && !step_resume_break_duplicate)
+    target_insert_breakpoint (step_resume_break_address,
+			      step_resume_break_shadow);
+}
+
+static void
+remove_step_breakpoint ()
+{
+  if (step_resume_break_address && !step_resume_break_duplicate)
+    target_remove_breakpoint (step_resume_break_address,
+			      step_resume_break_shadow);
+}
+
+static void
+sig_print_header ()
+{
+  printf_filtered ("Signal\t\tStop\tPrint\tPass to program\tDescription\n");
+}
+
+static void
+sig_print_info (number)
+     int number;
+{
+  char *abbrev = sig_abbrev(number);
+  if (abbrev == NULL)
+    printf_filtered ("%d\t\t", number);
+  else
+    printf_filtered ("SIG%s (%d)\t", abbrev, number);
+  printf_filtered ("%s\t", signal_stop[number] ? "Yes" : "No");
+  printf_filtered ("%s\t", signal_print[number] ? "Yes" : "No");
+  printf_filtered ("%s\t\t", signal_program[number] ? "Yes" : "No");
+  printf_filtered ("%s\n", sys_siglist[number]);
+}
+
+/* Specify how various signals in the inferior should be handled.  */
+
+static void
+handle_command (args, from_tty)
+     char *args;
+     int from_tty;
+{
+  register char *p = args;
+  int signum = 0;
+  register int digits, wordlen;
+  char *nextarg;
+
+  if (!args)
+    error_no_arg ("signal to handle");
+
+  while (*p)
+    {
+      /* Find the end of the next word in the args.  */
+      for (wordlen = 0;
+	   p[wordlen] && p[wordlen] != ' ' && p[wordlen] != '\t';
+	   wordlen++);
+      /* Set nextarg to the start of the word after the one we just
+	 found, and null-terminate this one.  */
+      if (p[wordlen] == '\0')
+	nextarg = p + wordlen;
+      else
+	{
+	  p[wordlen] = '\0';
+	  nextarg = p + wordlen + 1;
+	}
+      
+
+      for (digits = 0; p[digits] >= '0' && p[digits] <= '9'; digits++);
+
+      if (signum == 0)
+	{
+	  /* It is the first argument--must be the signal to operate on.  */
+	  if (digits == wordlen)
+	    {
+	      /* Numeric.  */
+	      signum = atoi (p);
+	      if (signum <= 0 || signum >= NSIG)
+		{
+		  p[wordlen] = '\0';
+		  error ("Invalid signal %s given as argument to \"handle\".", p);
+		}
+	    }
+	  else
+	    {
+	      /* Symbolic.  */
+	      signum = sig_number (p);
+	      if (signum == -1)
+		error ("No such signal \"%s\"", p);
+	    }
+
+	  if (signum == SIGTRAP || signum == SIGINT)
+	    {
+	      if (!query ("SIG%s is used by the debugger.\nAre you sure you want to change it? ", sig_abbrev (signum)))
+		error ("Not confirmed.");
+	    }
+	}
+      /* Else, if already got a signal number, look for flag words
+	 saying what to do for it.  */
+      else if (!strncmp (p, "stop", wordlen))
+	{
+	  signal_stop[signum] = 1;
+	  signal_print[signum] = 1;
+	}
+      else if (wordlen >= 2 && !strncmp (p, "print", wordlen))
+	signal_print[signum] = 1;
+      else if (wordlen >= 2 && !strncmp (p, "pass", wordlen))
+	signal_program[signum] = 1;
+      else if (!strncmp (p, "ignore", wordlen))
+	signal_program[signum] = 0;
+      else if (wordlen >= 3 && !strncmp (p, "nostop", wordlen))
+	signal_stop[signum] = 0;
+      else if (wordlen >= 4 && !strncmp (p, "noprint", wordlen))
+	{
+	  signal_print[signum] = 0;
+	  signal_stop[signum] = 0;
+	}
+      else if (wordlen >= 4 && !strncmp (p, "nopass", wordlen))
+	signal_program[signum] = 0;
+      else if (wordlen >= 3 && !strncmp (p, "noignore", wordlen))
+	signal_program[signum] = 1;
+      /* Not a number and not a recognized flag word => complain.  */
+      else
+	{
+	  error ("Unrecognized flag word: \"%s\".", p);
+	}
+
+      /* Find start of next word.  */
+      p = nextarg;
+      while (*p == ' ' || *p == '\t') p++;
+    }
+
+  if (from_tty)
+    {
+      /* Show the results.  */
+      sig_print_header ();
+      sig_print_info (signum);
+    }
+}
+
+/* Print current contents of the tables set by the handle command.  */
+
+static void
+signals_info (signum_exp)
+     char *signum_exp;
+{
+  register int i;
+  sig_print_header ();
+
+  if (signum_exp)
+    {
+      /* First see if this is a symbol name.  */
+      i = sig_number (signum_exp);
+      if (i == -1)
+	{
+	  /* Nope, maybe it's an address which evaluates to a signal
+	     number.  */
+	  i = parse_and_eval_address (signum_exp);
+	  if (i >= NSIG || i < 0)
+	    error ("Signal number out of bounds.");
+	}
+      sig_print_info (i);
+      return;
+    }
+
+  printf_filtered ("\n");
+  for (i = 0; i < NSIG; i++)
+    {
+      QUIT;
+
+      sig_print_info (i);
+    }
+
+  printf_filtered ("\nUse the \"handle\" command to change these tables.\n");
+}
+
+/* Save all of the information associated with the inferior<==>gdb
+   connection.  INF_STATUS is a pointer to a "struct inferior_status"
+   (defined in inferior.h).  */
+
+void
+save_inferior_status (inf_status, restore_stack_info)
+     struct inferior_status *inf_status;
+     int restore_stack_info;
+{
+  inf_status->pc_changed = pc_changed;
+  inf_status->stop_signal = stop_signal;
+  inf_status->stop_pc = stop_pc;
+  inf_status->stop_frame_address = stop_frame_address;
+  inf_status->stop_step = stop_step;
+  inf_status->stop_stack_dummy = stop_stack_dummy;
+  inf_status->stopped_by_random_signal = stopped_by_random_signal;
+  inf_status->trap_expected = trap_expected;
+  inf_status->step_range_start = step_range_start;
+  inf_status->step_range_end = step_range_end;
+  inf_status->step_frame_address = step_frame_address;
+  inf_status->step_over_calls = step_over_calls;
+  inf_status->step_resume_break_address = step_resume_break_address;
+  inf_status->stop_after_trap = stop_after_trap;
+  inf_status->stop_soon_quietly = stop_soon_quietly;
+  /* Save original bpstat chain here; replace it with copy of chain. 
+     If caller's caller is walking the chain, they'll be happier if we
+     hand them back the original chain when restore_i_s is called.  */
+  inf_status->stop_bpstat = stop_bpstat;
+  stop_bpstat = bpstat_copy (stop_bpstat);
+  inf_status->breakpoint_proceeded = breakpoint_proceeded;
+  inf_status->restore_stack_info = restore_stack_info;
+  inf_status->proceed_to_finish = proceed_to_finish;
+  
+  bcopy (stop_registers, inf_status->stop_registers, REGISTER_BYTES);
+  
+  record_selected_frame (&(inf_status->selected_frame_address),
+			 &(inf_status->selected_level));
+  return;
+}
+
+void
+restore_inferior_status (inf_status)
+     struct inferior_status *inf_status;
+{
+  FRAME fid;
+  int level = inf_status->selected_level;
+
+  pc_changed = inf_status->pc_changed;
+  stop_signal = inf_status->stop_signal;
+  stop_pc = inf_status->stop_pc;
+  stop_frame_address = inf_status->stop_frame_address;
+  stop_step = inf_status->stop_step;
+  stop_stack_dummy = inf_status->stop_stack_dummy;
+  stopped_by_random_signal = inf_status->stopped_by_random_signal;
+  trap_expected = inf_status->trap_expected;
+  step_range_start = inf_status->step_range_start;
+  step_range_end = inf_status->step_range_end;
+  step_frame_address = inf_status->step_frame_address;
+  step_over_calls = inf_status->step_over_calls;
+  step_resume_break_address = inf_status->step_resume_break_address;
+  stop_after_trap = inf_status->stop_after_trap;
+  stop_soon_quietly = inf_status->stop_soon_quietly;
+  bpstat_clear (&stop_bpstat);
+  stop_bpstat = inf_status->stop_bpstat;
+  breakpoint_proceeded = inf_status->breakpoint_proceeded;
+  proceed_to_finish = inf_status->proceed_to_finish;
+
+  bcopy (inf_status->stop_registers, stop_registers, REGISTER_BYTES);
+
+  /* The inferior can be gone if the user types "print exit(0)"
+     (and perhaps other times).  */
+  if (target_has_stack && inf_status->restore_stack_info)
+    {
+      fid = find_relative_frame (get_current_frame (),
+				 &level);
+
+      if (fid == 0 ||
+	  FRAME_FP (fid) != inf_status->selected_frame_address ||
+	  level != 0)
+	{
+#if 0
+	  /* I'm not sure this error message is a good idea.  I have
+	     only seen it occur after "Can't continue previously
+	     requested operation" (we get called from do_cleanups), in
+	     which case it just adds insult to injury (one confusing
+	     error message after another.  Besides which, does the
+	     user really care if we can't restore the previously
+	     selected frame?  */
+	  fprintf (stderr, "Unable to restore previously selected frame.\n");
+#endif
+	  select_frame (get_current_frame (), 0);
+	  return;
+	}
+      
+      select_frame (fid, inf_status->selected_level);
+    }
+}
+
+
+void
+_initialize_infrun ()
+{
+  register int i;
+
+  add_info ("signals", signals_info,
+	    "What debugger does when program gets various signals.\n\
+Specify a signal number as argument to print info on that signal only.");
+
+  add_com ("handle", class_run, handle_command,
+	   "Specify how to handle a signal.\n\
+Args are signal number followed by flags.\n\
+Flags allowed are \"stop\", \"print\", \"pass\",\n\
+ \"nostop\", \"noprint\" or \"nopass\".\n\
+Print means print a message if this signal happens.\n\
+Stop means reenter debugger if this signal happens (implies print).\n\
+Pass means let program see this signal; otherwise program doesn't know.\n\
+Pass and Stop may be combined.");
+
+  for (i = 0; i < NSIG; i++)
+    {
+      signal_stop[i] = 1;
+      signal_print[i] = 1;
+      signal_program[i] = 1;
+    }
+
+  /* Signals caused by debugger's own actions
+     should not be given to the program afterwards.  */
+  signal_program[SIGTRAP] = 0;
+  signal_program[SIGINT] = 0;
+
+  /* Signals that are not errors should not normally enter the debugger.  */
+#ifdef SIGALRM
+  signal_stop[SIGALRM] = 0;
+  signal_print[SIGALRM] = 0;
+#endif /* SIGALRM */
+#ifdef SIGVTALRM
+  signal_stop[SIGVTALRM] = 0;
+  signal_print[SIGVTALRM] = 0;
+#endif /* SIGVTALRM */
+#ifdef SIGPROF
+  signal_stop[SIGPROF] = 0;
+  signal_print[SIGPROF] = 0;
+#endif /* SIGPROF */
+#ifdef SIGCHLD
+  signal_stop[SIGCHLD] = 0;
+  signal_print[SIGCHLD] = 0;
+#endif /* SIGCHLD */
+#ifdef SIGCLD
+  signal_stop[SIGCLD] = 0;
+  signal_print[SIGCLD] = 0;
+#endif /* SIGCLD */
+#ifdef SIGIO
+  signal_stop[SIGIO] = 0;
+  signal_print[SIGIO] = 0;
+#endif /* SIGIO */
+#ifdef SIGURG
+  signal_stop[SIGURG] = 0;
+  signal_print[SIGURG] = 0;
+#endif /* SIGURG */
+}
+