X-Git-Url: http://review.tizen.org/git/?a=blobdiff_plain;f=trap.c;h=2d5934f1a0c85272469ccee7cf3c7fd62cf91332;hb=f1be666c7d78939ad775078d290bec2758fa29a2;hp=139dc2a6fa6b6bc20c1c10c48529f52a85dde454;hpb=ccc6cda312fea9f0468ee65b8f368e9653e1380b;p=platform%2Fupstream%2Fbash.git

diff --git a/trap.c b/trap.c
index 139dc2a..2d5934f 100644
--- a/trap.c
+++ b/trap.c
@@ -1,13 +1,13 @@
 /* trap.c -- Not the trap command, but useful functions for manipulating
    those objects.  The trap command is in builtins/trap.def. */
 
-/* Copyright (C) 1987, 1991 Free Software Foundation, Inc.
+/* Copyright (C) 1987-2006 Free Software Foundation, Inc.
 
    This file is part of GNU Bash, the Bourne Again SHell.
 
    Bash 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
+   Software Foundation; either version 2, or (at your option) any later
    version.
 
    Bash is distributed in the hope that it will be useful, but WITHOUT ANY
@@ -17,28 +17,35 @@
 
    You should have received a copy of the GNU General Public License along
    with Bash; see the file COPYING.  If not, write to the Free Software
-   Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. */
+   Foundation, 59 Temple Place, Suite 330, Boston, MA 02111 USA. */
 
 #include "config.h"
 
-#include <stdio.h>
+#if defined (HAVE_UNISTD_H)
+#  include <unistd.h>
+#endif
 
 #include "bashtypes.h"
-#include "trap.h"
+#include "bashansi.h"
 
-#if defined (HAVE_STRING_H)
-#  include <string.h>
-#else /* !HAVE_STRING_H */
-#  include <strings.h>
-#endif /* !HAVE_STRING_H */
+#include <stdio.h>
+#include <errno.h>
 
-#if defined (HAVE_UNISTD_H)
-#  include <unistd.h>
-#endif
+#include "bashintl.h"
+
+#include "trap.h"
 
 #include "shell.h"
+#include "flags.h"
+#include "input.h"	/* for save_token_state, restore_token_state */
 #include "signames.h"
+#include "builtins.h"
 #include "builtins/common.h"
+#include "builtins/builtext.h"
+
+#ifndef errno
+extern int errno;
+#endif
 
 /* Flags which describe the current handling state of a signal. */
 #define SIG_INHERITED   0x0	/* Value inherited from parent. */
@@ -50,17 +57,33 @@
 #define SIG_CHANGED	0x20	/* Trap value changed in trap handler. */
 #define SIG_IGNORED	0x40	/* The signal is currently being ignored. */
 
+#define SPECIAL_TRAP(s)	((s) == EXIT_TRAP || (s) == DEBUG_TRAP || (s) == ERROR_TRAP || (s) == RETURN_TRAP)
+
 /* An array of such flags, one for each signal, describing what the
    shell will do with a signal.  DEBUG_TRAP == NSIG; some code below
    assumes this. */
-static int sigmodes[NSIG+1];
+static int sigmodes[BASH_NSIG];
 
-static void change_signal (), restore_signal ();
+static void free_trap_command __P((int));
+static void change_signal __P((int, char *));
+
+static void get_original_signal __P((int));
+
+static int _run_trap_internal __P((int, char *));
+
+static void reset_signal __P((int));
+static void restore_signal __P((int));
+static void reset_or_restore_signal_handlers __P((sh_resetsig_func_t *));
 
 /* Variables used here but defined in other files. */
-extern int interactive_shell, interactive;
-extern int interrupt_immediately;
 extern int last_command_exit_value;
+extern int line_number;
+
+extern char *this_command_name;
+extern sh_builtin_func_t *this_shell_builtin;
+extern procenv_t wait_intr_buf;
+extern int return_catch_flag, return_catch_value;
+extern int subshell_level;
 
 /* The list of things to do originally, before we started trapping. */
 SigHandler *original_signals[NSIG];
@@ -70,7 +93,7 @@ SigHandler *original_signals[NSIG];
    DEFAULT_SIG, which means do whatever you were going to do before
    you were so rudely interrupted, or IGNORE_SIG, which says ignore
    this signal. */
-char *trap_list[NSIG+1];
+char *trap_list[BASH_NSIG];
 
 /* A bitmap of signals received for which we have trap handlers. */
 int pending_traps[NSIG];
@@ -81,16 +104,36 @@ int pending_traps[NSIG];
    trap command (e.g., when `return' is executed in the trap command). */
 int running_trap;
 
+/* Set to last_command_exit_value before running a trap. */
+int trap_saved_exit_value;
+
+/* The (trapped) signal received while executing in the `wait' builtin */
+int wait_signal_received;
+
 /* A value which can never be the target of a trap handler. */
 #define IMPOSSIBLE_TRAP_HANDLER (SigHandler *)initialize_traps
 
+#define GETORIGSIG(sig) \
+  do { \
+    original_signals[sig] = (SigHandler *)set_signal_handler (sig, SIG_DFL); \
+    set_signal_handler (sig, original_signals[sig]); \
+    if (original_signals[sig] == SIG_IGN) \
+      sigmodes[sig] |= SIG_HARD_IGNORE; \
+  } while (0)
+
+#define GET_ORIGINAL_SIGNAL(sig) \
+  if (sig && sig < NSIG && original_signals[sig] == IMPOSSIBLE_TRAP_HANDLER) \
+    GETORIGSIG(sig)
+
 void
 initialize_traps ()
 {
   register int i;
 
-  trap_list[EXIT_TRAP] = trap_list[DEBUG_TRAP] = (char *)NULL;
-  sigmodes[EXIT_TRAP] = sigmodes[DEBUG_TRAP] = SIG_INHERITED;
+  initialize_signames();
+
+  trap_list[EXIT_TRAP] = trap_list[DEBUG_TRAP] = trap_list[ERROR_TRAP] = trap_list[RETURN_TRAP] = (char *)NULL;
+  sigmodes[EXIT_TRAP] = sigmodes[DEBUG_TRAP] = sigmodes[ERROR_TRAP] = sigmodes[RETURN_TRAP] = SIG_INHERITED;
   original_signals[EXIT_TRAP] = IMPOSSIBLE_TRAP_HANDLER;
 
   for (i = 1; i < NSIG; i++)
@@ -103,37 +146,61 @@ initialize_traps ()
 
   /* Show which signals are treated specially by the shell. */
 #if defined (SIGCHLD)
-  original_signals[SIGCHLD] =
-    (SigHandler *) set_signal_handler (SIGCHLD, SIG_DFL);
-  set_signal_handler (SIGCHLD, original_signals[SIGCHLD]);
+  GETORIGSIG (SIGCHLD);
   sigmodes[SIGCHLD] |= (SIG_SPECIAL | SIG_NO_TRAP);
 #endif /* SIGCHLD */
 
-  original_signals[SIGINT] =
-    (SigHandler *) set_signal_handler (SIGINT, SIG_DFL);
-  set_signal_handler (SIGINT, original_signals[SIGINT]);
+  GETORIGSIG (SIGINT);
   sigmodes[SIGINT] |= SIG_SPECIAL;
 
-  original_signals[SIGQUIT] =
-    (SigHandler *) set_signal_handler (SIGQUIT, SIG_DFL);
-  set_signal_handler (SIGQUIT, original_signals[SIGQUIT]);
+#if defined (__BEOS__)
+  /* BeOS sets SIGINT to SIG_IGN! */
+  original_signals[SIGINT] = SIG_DFL;
+  sigmodes[SIGINT] &= ~SIG_HARD_IGNORE;
+#endif
+
+  GETORIGSIG (SIGQUIT);
   sigmodes[SIGQUIT] |= SIG_SPECIAL;
 
   if (interactive)
     {
-      original_signals[SIGTERM] =
-	(SigHandler *)set_signal_handler (SIGTERM, SIG_DFL);
-      set_signal_handler (SIGTERM, original_signals[SIGTERM]);
+      GETORIGSIG (SIGTERM);
       sigmodes[SIGTERM] |= SIG_SPECIAL;
     }
 }
 
+#ifdef INCLUDE_UNUSED
+/* Return a printable representation of the trap handler for SIG. */
+static char *
+trap_handler_string (sig)
+     int sig;
+{
+  if (trap_list[sig] == (char *)DEFAULT_SIG)
+    return "DEFAULT_SIG";
+  else if (trap_list[sig] == (char *)IGNORE_SIG)
+    return "IGNORE_SIG";
+  else if (trap_list[sig] == (char *)IMPOSSIBLE_TRAP_HANDLER)
+    return "IMPOSSIBLE_TRAP_HANDLER";
+  else if (trap_list[sig])
+    return trap_list[sig];
+  else
+    return "NULL";
+}
+#endif
+
 /* Return the print name of this signal. */
 char *
 signal_name (sig)
      int sig;
 {
-  return ((sig > NSIG || sig < 0) ? "bad signal number" : signal_names[sig]);
+  char *ret;
+
+  /* on cygwin32, signal_names[sig] could be null */
+  ret = (sig >= BASH_NSIG || sig < 0 || signal_names[sig] == NULL)
+	? _("invalid signal number")
+	: signal_names[sig];
+
+  return ret;
 }
 
 /* Turn a string into a signal number, or a number into
@@ -141,18 +208,47 @@ signal_name (sig)
    then (int)2 is returned.  Return NO_SIG if STRING doesn't
    contain a valid signal descriptor. */
 int
-decode_signal (string)
+decode_signal (string, flags)
      char *string;
+     int flags;
 {
-  long sig;
+  intmax_t sig;
+  char *name;
 
   if (legal_number (string, &sig))
-    return ((sig >= 0 && sig <= NSIG) ? (int)sig : NO_SIG);
+    return ((sig >= 0 && sig < NSIG) ? (int)sig : NO_SIG);
+
+  /* A leading `SIG' may be omitted. */
+  for (sig = 0; sig < BASH_NSIG; sig++)
+    {
+      name = signal_names[sig];
+      if (name == 0 || name[0] == '\0')
+	continue;
 
-  for (sig = 0; sig <= NSIG; sig++)
-    if (strcasecmp (string, signal_names[sig]) == 0 ||
-	strcasecmp (string, &(signal_names[sig])[3]) == 0)
-      return ((int)sig);
+      /* Check name without the SIG prefix first case sensitivly or
+	 insensitively depending on whether flags includes DSIG_NOCASE */
+      if (STREQN (name, "SIG", 3))
+	{
+	  name += 3;
+
+	  if ((flags & DSIG_NOCASE) && strcasecmp (string, name) == 0)
+	    return ((int)sig);
+	  else if ((flags & DSIG_NOCASE) == 0 && strcmp (string, name) == 0)
+	    return ((int)sig);
+	  /* If we can't use the `SIG' prefix to match, punt on this
+	     name now. */
+	  else if ((flags & DSIG_SIGPREFIX) == 0)
+	    continue;
+	}
+
+      /* Check name with SIG prefix case sensitively or insensitively
+	 depending on whether flags includes DSIG_NOCASE */
+      name = signal_names[sig];
+      if ((flags & DSIG_NOCASE) && strcasecmp (string, name) == 0)
+	return ((int)sig);
+      else if ((flags & DSIG_NOCASE) == 0 && strcmp (string, name) == 0)
+	return ((int)sig);
+    }
 
   return (NO_SIG);
 }
@@ -164,7 +260,7 @@ void
 run_pending_traps ()
 {
   register int sig;
-  int old_exit_value;
+  int old_exit_value, *token_state;
 
   if (catch_flag == 0)		/* simple optimization */
     return;
@@ -177,7 +273,7 @@ run_pending_traps ()
   for (sig = 1; sig < NSIG; sig++)
     {
       /* XXX this could be made into a counter by using
-         while (pending_traps[sig]--) instead of the if statement. */
+	 while (pending_traps[sig]--) instead of the if statement. */
       if (pending_traps[sig])
 	{
 #if defined (HAVE_POSIX_SIGNALS)
@@ -199,8 +295,38 @@ run_pending_traps ()
 	      run_interrupt_trap ();
 	      CLRINTERRUPT;
 	    }
+	  else if (trap_list[sig] == (char *)DEFAULT_SIG ||
+		   trap_list[sig] == (char *)IGNORE_SIG ||
+		   trap_list[sig] == (char *)IMPOSSIBLE_TRAP_HANDLER)
+	    {
+	      /* This is possible due to a race condition.  Say a bash
+		 process has SIGTERM trapped.  A subshell is spawned
+		 using { list; } & and the parent does something and kills
+		 the subshell with SIGTERM.  It's possible for the subshell
+		 to set pending_traps[SIGTERM] to 1 before the code in
+		 execute_cmd.c eventually calls restore_original_signals
+		 to reset the SIGTERM signal handler in the subshell.  The
+		 next time run_pending_traps is called, pending_traps[SIGTERM]
+		 will be 1, but the trap handler in trap_list[SIGTERM] will
+		 be invalid (probably DEFAULT_SIG, but it could be IGNORE_SIG).
+		 Unless we catch this, the subshell will dump core when
+		 trap_list[SIGTERM] == DEFAULT_SIG, because DEFAULT_SIG is
+		 usually 0x0. */
+	      internal_warning (_("run_pending_traps: bad value in trap_list[%d]: %p"),
+				sig, trap_list[sig]);
+	      if (trap_list[sig] == (char *)DEFAULT_SIG)
+		{
+		  internal_warning (_("run_pending_traps: signal handler is SIG_DFL, resending %d (%s) to myself"), sig, signal_name (sig));
+		  kill (getpid (), sig);
+		}
+	    }
 	  else
-	    parse_and_execute (savestring (trap_list[sig]), "trap", 0);
+	    {
+	      token_state = save_token_state ();
+	      parse_and_execute (savestring (trap_list[sig]), "trap", SEVAL_NONINT|SEVAL_NOHIST);
+	      restore_token_state (token_state);
+	      free (token_state);
+	    }
 
 	  pending_traps[sig] = 0;
 
@@ -221,12 +347,15 @@ sighandler
 trap_handler (sig)
      int sig;
 {
+  int oerrno;
+
   if ((sig >= NSIG) ||
       (trap_list[sig] == (char *)DEFAULT_SIG) ||
       (trap_list[sig] == (char *)IGNORE_SIG))
-    programming_error ("trap_handler: bad signal %d", sig);
+    programming_error (_("trap_handler: bad signal %d"), sig);
   else
     {
+      oerrno = errno;
 #if defined (MUST_REINSTALL_SIGHANDLERS)
       set_signal_handler (sig, trap_handler);
 #endif /* MUST_REINSTALL_SIGHANDLERS */
@@ -234,14 +363,24 @@ trap_handler (sig)
       catch_flag = 1;
       pending_traps[sig]++;
 
+      if (interrupt_immediately && this_shell_builtin && (this_shell_builtin == wait_builtin))
+	{
+	  wait_signal_received = sig;
+	  longjmp (wait_intr_buf, 1);
+	}
+
       if (interrupt_immediately)
 	run_pending_traps ();
+
+      errno = oerrno;
     }
 
   SIGRETURN (0);
 }
 
 #if defined (JOB_CONTROL) && defined (SIGCHLD)
+
+#ifdef INCLUDE_UNUSED
 /* Make COMMAND_STRING be executed when SIGCHLD is caught. */
 void
 set_sigchld_trap (command_string)
@@ -249,9 +388,10 @@ set_sigchld_trap (command_string)
 {
   set_signal (SIGCHLD, command_string);
 }
+#endif
 
-/* Make COMMAND_STRING be executed when SIGCHLD is caught iff the current
-   SIGCHLD trap handler is DEFAULT_SIG. */
+/* Make COMMAND_STRING be executed when SIGCHLD is caught iff SIGCHLD
+   is not already trapped. */
 void
 maybe_set_sigchld_trap (command_string)
      char *command_string;
@@ -269,11 +409,27 @@ set_debug_trap (command)
 }
 
 void
+set_error_trap (command)
+     char *command;
+{
+  set_signal (ERROR_TRAP, command);
+}
+
+void
+set_return_trap (command)
+     char *command;
+{
+  set_signal (RETURN_TRAP, command);
+}
+
+#ifdef INCLUDE_UNUSED
+void
 set_sigint_trap (command)
      char *command;
 {
   set_signal (SIGINT, command);
 }
+#endif
 
 /* Reset the SIGINT handler so that subshells that are doing `shellsy'
    things, like waiting for command substitution or executing commands
@@ -295,7 +451,21 @@ set_sigint_handler ()
   else if (interactive)	/* XXX - was interactive_shell */
     return (set_signal_handler (SIGINT, sigint_sighandler));
   else
-    return (set_signal_handler (SIGINT, termination_unwind_protect));
+    return (set_signal_handler (SIGINT, termsig_sighandler));
+}
+
+/* Return the correct handler for signal SIG according to the values in
+   sigmodes[SIG]. */
+SigHandler *
+trap_to_sighandler (sig)
+     int sig;
+{
+  if (sigmodes[sig] & (SIG_IGNORED|SIG_HARD_IGNORE))
+    return (SIG_IGN);
+  else if (sigmodes[sig] & SIG_TRAPPED)
+    return (trap_handler);
+  else
+    return (SIG_DFL);
 }
 
 /* Set SIG to call STRING as a command. */
@@ -304,9 +474,11 @@ set_signal (sig, string)
      int sig;
      char *string;
 {
-  if (sig == DEBUG_TRAP || sig == EXIT_TRAP)
+  if (SPECIAL_TRAP (sig))
     {
       change_signal (sig, savestring (string));
+      if (sig == EXIT_TRAP && interactive == 0)
+	initialize_terminating_signals ();
       return;
     }
 
@@ -321,17 +493,9 @@ set_signal (sig, string)
     {
       /* If we aren't sure of the original value, check it. */
       if (original_signals[sig] == IMPOSSIBLE_TRAP_HANDLER)
-	{
-	  original_signals[sig] = (SigHandler *)set_signal_handler (sig, SIG_DFL);
-	  set_signal_handler (sig, original_signals[sig]);
-	}
-
-      /* Signals ignored on entry to the shell cannot be trapped or reset. */
+        GETORIGSIG (sig);
       if (original_signals[sig] == SIG_IGN)
-	{
-	  sigmodes[sig] |= SIG_HARD_IGNORE;
-	  return;
-	}
+	return;
     }
 
   /* Only change the system signal handler if SIG_NO_TRAP is not set.
@@ -366,7 +530,8 @@ change_signal (sig, value)
      int sig;
      char *value;
 {
-  free_trap_command (sig);
+  if ((sigmodes[sig] & SIG_INPROGRESS) == 0)
+    free_trap_command (sig);
   trap_list[sig] = value;
 
   sigmodes[sig] |= SIG_TRAPPED;
@@ -378,25 +543,13 @@ change_signal (sig, value)
     sigmodes[sig] |= SIG_CHANGED;
 }
 
-#define GET_ORIGINAL_SIGNAL(sig) \
-  if (sig && sig < NSIG && original_signals[sig] == IMPOSSIBLE_TRAP_HANDLER) \
-    get_original_signal (sig)
-
 static void
 get_original_signal (sig)
      int sig;
 {
   /* If we aren't sure the of the original value, then get it. */
   if (original_signals[sig] == (SigHandler *)IMPOSSIBLE_TRAP_HANDLER)
-    {
-      original_signals[sig] =
-	(SigHandler *) set_signal_handler (sig, SIG_DFL);
-      set_signal_handler (sig, original_signals[sig]);
-
-      /* Signals ignored on entry to the shell cannot be trapped. */
-      if (original_signals[sig] == SIG_IGN)
-	sigmodes[sig] |= SIG_HARD_IGNORE;
-    }
+    GETORIGSIG (sig);
 }
 
 /* Restore the default action for SIG; i.e., the action the shell
@@ -407,11 +560,15 @@ void
 restore_default_signal (sig)
      int sig;
 {
-  if (sig == DEBUG_TRAP || sig == EXIT_TRAP)
+  if (SPECIAL_TRAP (sig))
     {
-      free_trap_command (sig);
+      if ((sig != DEBUG_TRAP && sig != ERROR_TRAP && sig != RETURN_TRAP) ||
+	  (sigmodes[sig] & SIG_INPROGRESS) == 0)
+	free_trap_command (sig);
       trap_list[sig] = (char *)NULL;
       sigmodes[sig] &= ~SIG_TRAPPED;
+      if (sigmodes[sig] & SIG_INPROGRESS)
+	sigmodes[sig] |= SIG_CHANGED;
       return;
     }
 
@@ -442,7 +599,7 @@ void
 ignore_signal (sig)
      int sig;
 {
-  if ((sig == EXIT_TRAP || sig == DEBUG_TRAP) && ((sigmodes[sig] & SIG_IGNORED) == 0))
+  if (SPECIAL_TRAP (sig) && ((sigmodes[sig] & SIG_IGNORED) == 0))
     {
       change_signal (sig, (char *)IGNORE_SIG);
       return;
@@ -474,9 +631,10 @@ int
 run_exit_trap ()
 {
   char *trap_command;
-  int code, old_exit_value;
+  int code, function_code, retval;
 
-  old_exit_value = last_command_exit_value;
+  trap_saved_exit_value = last_command_exit_value;
+  function_code = 0;
 
   /* Run the trap only if signal 0 is trapped and not ignored, and we are not
      currently running in the trap handler (call to exit in the list of
@@ -488,17 +646,34 @@ run_exit_trap ()
       sigmodes[EXIT_TRAP] &= ~SIG_TRAPPED;
       sigmodes[EXIT_TRAP] |= SIG_INPROGRESS;
 
+      retval = trap_saved_exit_value;
+      running_trap = 1;
+
       code = setjmp (top_level);
 
-      if (code == 0)
-	parse_and_execute (trap_command, "exit trap", 0);
+      /* If we're in a function, make sure return longjmps come here, too. */
+      if (return_catch_flag)
+	function_code = setjmp (return_catch);
+
+      if (code == 0 && function_code == 0)
+	{
+	  reset_parser ();
+	  parse_and_execute (trap_command, "exit trap", SEVAL_NONINT|SEVAL_NOHIST);
+	}
+      else if (code == ERREXIT)
+	retval = last_command_exit_value;
       else if (code == EXITPROG)
-        return (last_command_exit_value);
+	retval = last_command_exit_value;
+      else if (function_code != 0)
+        retval = return_catch_value;
       else
-	return (old_exit_value);
+	retval = trap_saved_exit_value;
+
+      running_trap = 0;
+      return retval;
     }
 
-  return (old_exit_value);
+  return (trap_saved_exit_value);
 }
 
 void
@@ -509,15 +684,18 @@ run_trap_cleanup (sig)
 }
 
 /* Run a trap command for SIG.  SIG is one of the signals the shell treats
-   specially. */
-static void
+   specially.  Returns the exit status of the executed trap command list. */
+static int
 _run_trap_internal (sig, tag)
      int sig;
      char *tag;
 {
   char *trap_command, *old_trap;
-  int old_exit_value;
+  int trap_exit_value, *token_state;
+  int save_return_catch_flag, function_code;
+  procenv_t save_return_catch;
 
+  trap_exit_value = function_code = 0;
   /* Run the trap only if SIG is trapped and not ignored, and we are not
      currently executing in the trap handler. */
   if ((sigmodes[sig] & SIG_TRAPPED) && ((sigmodes[sig] & SIG_IGNORED) == 0) &&
@@ -530,26 +708,102 @@ _run_trap_internal (sig, tag)
       trap_command =  savestring (old_trap);
 
       running_trap = sig + 1;
-      old_exit_value = last_command_exit_value;
-      parse_and_execute (trap_command, tag, 0);
-      last_command_exit_value = old_exit_value;
+      trap_saved_exit_value = last_command_exit_value;
+
+      token_state = save_token_state ();
+
+      /* If we're in a function, make sure return longjmps come here, too. */
+      save_return_catch_flag = return_catch_flag;
+      if (return_catch_flag)
+	{
+	  COPY_PROCENV (return_catch, save_return_catch);
+	  function_code = setjmp (return_catch);
+	}
+
+      if (function_code == 0)
+	parse_and_execute (trap_command, tag, SEVAL_NONINT|SEVAL_NOHIST);
+
+      restore_token_state (token_state);
+      free (token_state);
+
+      trap_exit_value = last_command_exit_value;
+      last_command_exit_value = trap_saved_exit_value;
       running_trap = 0;
 
       sigmodes[sig] &= ~SIG_INPROGRESS;
 
       if (sigmodes[sig] & SIG_CHANGED)
 	{
-	  free (old_trap);
+#if 0
+	  /* Special traps like EXIT, DEBUG, RETURN are handled explicitly in
+	     the places where they can be changed using unwind-protects.  For
+	     example, look at execute_cmd.c:execute_function(). */
+	  if (SPECIAL_TRAP (sig) == 0)
+#endif
+	    free (old_trap);
 	  sigmodes[sig] &= ~SIG_CHANGED;
 	}
+
+      if (save_return_catch_flag)
+	{
+	  return_catch_flag = save_return_catch_flag;
+	  return_catch_value = trap_exit_value;
+	  COPY_PROCENV (save_return_catch, return_catch);
+	  if (function_code)
+	    longjmp (return_catch, 1);
+	}
     }
+
+  return trap_exit_value;
 }
 
-void
+int
 run_debug_trap ()
 {
-  if ((sigmodes[DEBUG_TRAP] & SIG_TRAPPED) && (sigmodes[DEBUG_TRAP] & SIG_INPROGRESS) == 0)
-    _run_trap_internal (DEBUG_TRAP, "debug trap");
+  int trap_exit_value;
+
+  /* XXX - question:  should the DEBUG trap inherit the RETURN trap? */
+  trap_exit_value = 0;
+  if ((sigmodes[DEBUG_TRAP] & SIG_TRAPPED) && ((sigmodes[DEBUG_TRAP] & SIG_IGNORED) == 0) && ((sigmodes[DEBUG_TRAP] & SIG_INPROGRESS) == 0))
+    {
+      trap_exit_value = _run_trap_internal (DEBUG_TRAP, "debug trap");
+      
+#if defined (DEBUGGER)
+      /* If we're in the debugger and the DEBUG trap returns 2 while we're in
+	 a function or sourced script, we force a `return'. */
+      if (debugging_mode && trap_exit_value == 2 && return_catch_flag)
+	{
+	  return_catch_value = trap_exit_value;
+	  longjmp (return_catch, 1);
+	}
+#endif
+    }
+  return trap_exit_value;
+}
+
+void
+run_error_trap ()
+{
+  if ((sigmodes[ERROR_TRAP] & SIG_TRAPPED) && ((sigmodes[ERROR_TRAP] & SIG_IGNORED) == 0) && (sigmodes[ERROR_TRAP] & SIG_INPROGRESS) == 0)
+    _run_trap_internal (ERROR_TRAP, "error trap");
+}
+
+void
+run_return_trap ()
+{
+  int old_exit_value;
+
+#if 0
+  if ((sigmodes[DEBUG_TRAP] & SIG_TRAPPED) && (sigmodes[DEBUG_TRAP] & SIG_INPROGRESS))
+    return;
+#endif
+
+  if ((sigmodes[RETURN_TRAP] & SIG_TRAPPED) && ((sigmodes[RETURN_TRAP] & SIG_IGNORED) == 0) && (sigmodes[RETURN_TRAP] & SIG_INPROGRESS) == 0)
+    {
+      old_exit_value = last_command_exit_value;
+      _run_trap_internal (RETURN_TRAP, "return trap");
+      last_command_exit_value = old_exit_value;
+    }
 }
 
 /* Run a trap set on SIGINT.  This is called from throw_to_top_level (), and
@@ -560,6 +814,7 @@ run_interrupt_trap ()
   _run_trap_internal (SIGINT, "interrupt trap");
 }
 
+#ifdef INCLUDE_UNUSED
 /* Free all the allocated strings in the list of traps and reset the trap
    values to the default. */
 void
@@ -567,14 +822,15 @@ free_trap_strings ()
 {
   register int i;
 
-  for (i = 0; i < NSIG+1; i++)
+  for (i = 0; i < BASH_NSIG; i++)
     {
       free_trap_command (i);
       trap_list[i] = (char *)DEFAULT_SIG;
       sigmodes[i] &= ~SIG_TRAPPED;
     }
-  trap_list[DEBUG_TRAP] = trap_list[EXIT_TRAP] = (char *)NULL;
+  trap_list[DEBUG_TRAP] = trap_list[EXIT_TRAP] = trap_list[ERROR_TRAP] = trap_list[RETURN_TRAP] = (char *)NULL;
 }
+#endif
 
 /* Reset the handler for SIG to the original value. */
 static void
@@ -582,6 +838,7 @@ reset_signal (sig)
      int sig;
 {
   set_signal_handler (sig, original_signals[sig]);
+  sigmodes[sig] &= ~SIG_TRAPPED;
 }
 
 /* Set the handler signal SIG to the original and free any trap
@@ -597,17 +854,21 @@ restore_signal (sig)
 
 static void
 reset_or_restore_signal_handlers (reset)
-     VFunction *reset;
+     sh_resetsig_func_t *reset;
 {
   register int i;
 
   /* Take care of the exit trap first */
   if (sigmodes[EXIT_TRAP] & SIG_TRAPPED)
     {
-      free_trap_command (EXIT_TRAP);
-      trap_list[EXIT_TRAP] = (char *)NULL;
       sigmodes[EXIT_TRAP] &= ~SIG_TRAPPED;
+      if (reset != reset_signal)
+	{
+	  free_trap_command (EXIT_TRAP);
+	  trap_list[EXIT_TRAP] = (char *)NULL;
+	}
     }
+
   for (i = 1; i < NSIG; i++)
     {
       if (sigmodes[i] & SIG_TRAPPED)
@@ -620,8 +881,23 @@ reset_or_restore_signal_handlers (reset)
       else if (sigmodes[i] & SIG_SPECIAL)
 	(*reset) (i);
     }
+
+  /* Command substitution and other child processes don't inherit the
+     debug, error, or return traps.  If we're in the debugger, and the
+     `functrace' or `errtrace' options have been set, then let command
+     substitutions inherit them.  Let command substitution inherit the
+     RETURN trap if we're in the debugger and tracing functions. */
+  if (function_trace_mode == 0)
+    {
+      sigmodes[DEBUG_TRAP] &= ~SIG_TRAPPED;
+      sigmodes[RETURN_TRAP] &= ~SIG_TRAPPED;
+    }
+  if (error_trace_mode == 0)
+    sigmodes[ERROR_TRAP] &= ~SIG_TRAPPED;
 }
 
+/* Reset trapped signals to their original values, but don't free the
+   trap strings.  Called by the command substitution code. */
 void
 reset_signal_handlers ()
 {
@@ -657,6 +933,9 @@ maybe_call_trap_handler (sig)
 	case DEBUG_TRAP:
 	  run_debug_trap ();
 	  break;
+	case ERROR_TRAP:
+	  run_error_trap ();
+	  break;
 	default:
 	  trap_handler (sig);
 	  break;
@@ -695,3 +974,10 @@ set_signal_ignored (sig)
   sigmodes[sig] |= SIG_HARD_IGNORE;
   original_signals[sig] = SIG_IGN;
 }
+
+int
+signal_in_progress (sig)
+     int sig;
+{
+  return (sigmodes[sig] & SIG_INPROGRESS);
+}