2003-04-08 Elena Zannoni <ezannoni@redhat.com>

* infrun.c (stop_soon_quietly): Make it an enum, to better
	override the default behavior of handle_inferior_event.
	(clear_proceed_status): Update uses of stop_soon_quietly to
	reflect that it is now an enum.
	(start_remote): Ditto.
	(handle_inferior_event): Change logic a bit if stop_soon_quietly
	is set to handle the new GNU/Linux kernel behavior for
	attach/sigstop.  Update uses of stop_soon_quietly.
	* inferior.h (enum stop_kind): New enum.
	* infcmd.c (attach_command): Use STOP_QUIETLY_NO_SIGSTOP.
	Reset normal handle_inferior_event behavior, afterwards.
	* fork-child.c (startup_inferior): Update.
	* alpha-tdep.c (heuristic_proc_start): Update.
	* solib-svr4.c (svr4_solib_create_inferior_hook): Update.
	* solib-sunos.c (sunos_solib_create_inferior_hook): Update.
	* solib-osf.c (osf_solib_create_inferior_hook): Update.
	* solib-irix.c (irix_solib_create_inferior_hook): Update.
	* remote-vx.c (vx_create_inferior): Update.
	* mips-tdep.c (heuristic_proc_start): Update.

gdb/alpha-tdep.c

@@ -557,7 +557,7 @@ heuristic_proc_start (CORE_ADDR pc)
 	   stop_soon_quietly, but with this test, at least we
 	   don't print out warnings for every child forked (eg, on
 	   decstation).  22apr93 rich@cygnus.com.  */
-	if (!stop_soon_quietly)
+	if (stop_soon_quietly == NO_STOP_QUIETLY)
 	  {
 	    static int blurb_printed = 0;
 

gdb/fork-child.c

@@ -409,7 +409,8 @@ startup_inferior (int ntraps)
 #else
   while (1)
     {
-      stop_soon_quietly = 1;	/* Make wait_for_inferior be quiet */
+      /* Make wait_for_inferior be quiet */
+      stop_soon_quietly = STOP_QUIETLY;
       wait_for_inferior ();
       if (stop_signal != TARGET_SIGNAL_TRAP)
 	{
@@ -444,5 +445,5 @@ startup_inferior (int ntraps)
 	}
     }
 #endif /* STARTUP_INFERIOR */
-  stop_soon_quietly = 0;
+  stop_soon_quietly = NO_STOP_QUIETLY;
 }

gdb/infcmd.c

@@ -1910,8 +1910,13 @@ attach_command (char *args, int from_tty)
   /* No traps are generated when attaching to inferior under Mach 3
      or GNU hurd.  */
 #ifndef ATTACH_NO_WAIT
-  stop_soon_quietly = 1;
+  /* Careful here. See comments in inferior.h.  Basically some OSes
+     don't ignore SIGSTOPs on continue requests anymore.  We need a
+     way for handle_inferior_event to reset the stop_signal variable
+     after an attach, and this is what STOP_QUIETLY_NO_SIGSTOP is for.  */
+  stop_soon_quietly = STOP_QUIETLY_NO_SIGSTOP;
   wait_for_inferior ();
+  stop_soon_quietly = NO_STOP_QUIETLY;
 #endif
 
   /*

gdb/inferior.h

@@ -390,12 +390,37 @@ extern enum step_over_calls_kind step_over_calls;
 
 extern int step_multi;
 
-/* Nonzero means expecting a trap and caller will handle it themselves.
+/* Nonzero means expecting a trap and caller will handle it
-   It is used after attach, due to attaching to a process;
+   themselves.  It is used when running in the shell before the child
-   when running in the shell before the child program has been exec'd;
+   program has been exec'd; and when running some kinds of remote
-   and when running some kinds of remote stuff (FIXME?).  */
+   stuff (FIXME?).  */
 
-extern int stop_soon_quietly;
+/* It is also used after attach, due to attaching to a process. This
+   is a bit trickier.  When doing an attach, the kernel stops the
+   debuggee with a SIGSTOP.  On newer GNU/Linux kernels (>= 2.5.61)
+   the handling of SIGSTOP for a ptraced process has changed. Earlier
+   versions of the kernel would ignore these SIGSTOPs, while now
+   SIGSTOP is treated like any other signal, i.e. it is not muffled.
+   
+   If the gdb user does a 'continue' after the 'attach', gdb passes
+   the global variable stop_signal (which stores the signal from the
+   attach, SIGSTOP) to the ptrace(PTRACE_CONT,...)  call.  This is
+   problematic, because the kernel doesn't ignore such SIGSTOP
+   now. I.e. it is reported back to gdb, which in turn presents it
+   back to the user.
+ 
+   To avoid the problem, we use STOP_QUIETLY_NO_SIGSTOP, which allows
+   gdb to clear the value of stop_signal after the attach, so that it
+   is not passed back down to the kernel.  */
+
+enum stop_kind
+  {
+    NO_STOP_QUIETLY = 0,
+    STOP_QUIETLY,
+    STOP_QUIETLY_NO_SIGSTOP
+  };
+
+extern enum stop_kind stop_soon_quietly;
 
 /* Nonzero if proceed is being used for a "finish" command or a similar
    situation when stop_registers should be saved.  */

gdb/infrun.c

@@ -286,7 +286,7 @@ int stop_after_trap;
    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;
+enum stop_kind stop_soon_quietly;
 
 /* Nonzero if proceed is being used for a "finish" command or a similar
    situation when stop_registers should be saved.  */
@@ -659,7 +659,7 @@ clear_proceed_status (void)
   step_frame_id = null_frame_id;
   step_over_calls = STEP_OVER_UNDEBUGGABLE;
   stop_after_trap = 0;
-  stop_soon_quietly = 0;
+  stop_soon_quietly = NO_STOP_QUIETLY;
   proceed_to_finish = 0;
   breakpoint_proceeded = 1;	/* We're about to proceed... */
 
@@ -802,7 +802,7 @@ start_remote (void)
 {
   init_thread_list ();
   init_wait_for_inferior ();
-  stop_soon_quietly = 1;
+  stop_soon_quietly = STOP_QUIETLY;
   trap_expected = 0;
 
   /* Always go on waiting for the target, regardless of the mode. */
@@ -1258,7 +1258,7 @@ handle_inferior_event (struct execution_control_state *ecs)
          might be the shell which has just loaded some objects,
          otherwise add the symbols for the newly loaded objects.  */
 #ifdef SOLIB_ADD
-      if (!stop_soon_quietly)
+      if (stop_soon_quietly == NO_STOP_QUIETLY)
 	{
 	  /* Remove breakpoints, SOLIB_ADD might adjust
 	     breakpoint addresses via breakpoint_re_set.  */
@@ -1757,7 +1757,9 @@ handle_inferior_event (struct execution_control_state *ecs)
   if (stop_signal == TARGET_SIGNAL_TRAP
       || (breakpoints_inserted &&
 	  (stop_signal == TARGET_SIGNAL_ILL
-	   || stop_signal == TARGET_SIGNAL_EMT)) || stop_soon_quietly)
+	   || stop_signal == TARGET_SIGNAL_EMT))
+      || stop_soon_quietly == STOP_QUIETLY
+      || stop_soon_quietly == STOP_QUIETLY_NO_SIGSTOP)
     {
       if (stop_signal == TARGET_SIGNAL_TRAP && stop_after_trap)
 	{
@@ -1765,12 +1767,27 @@ handle_inferior_event (struct execution_control_state *ecs)
 	  stop_stepping (ecs);
 	  return;
 	}
-      if (stop_soon_quietly)
+
+      /* This is originated from start_remote(), start_inferior() and
+         shared libraries hook functions.  */
+      if (stop_soon_quietly == STOP_QUIETLY)
 	{
 	  stop_stepping (ecs);
 	  return;
 	}
 
+      /* This originates from attach_command().  We need to overwrite
+         the stop_signal here, because some kernels don't ignore a
+         SIGSTOP in a subsequent ptrace(PTRACE_SONT,SOGSTOP) call.
+         See more comments in inferior.h.  */
+      if (stop_soon_quietly == STOP_QUIETLY_NO_SIGSTOP)
+	{
+	  stop_stepping (ecs);
+	  if (stop_signal == TARGET_SIGNAL_STOP)
+	    stop_signal = TARGET_SIGNAL_0;
+	  return;
+	}
+
       /* Don't even think about breakpoints
          if just proceeded over a breakpoint.
 

gdb/mips-tdep.c

@@ -1821,7 +1821,7 @@ heuristic_proc_start (CORE_ADDR pc)
 	   stop_soon_quietly, but with this test, at least we
 	   don't print out warnings for every child forked (eg, on
 	   decstation).  22apr93 rich@cygnus.com.  */
-	if (!stop_soon_quietly)
+	if (stop_soon_quietly == NO_STOP_QUIETLY)
 	  {
 	    static int blurb_printed = 0;
 

gdb/remote-vx.c

@@ -67,7 +67,7 @@
 extern void vx_read_register ();
 extern void vx_write_register ();
 extern void symbol_file_command ();
-extern int stop_soon_quietly;	/* for wait_for_inferior */
+extern enum stop_kind stop_soon_quietly;	/* for wait_for_inferior */
 
 static int net_step ();
 static int net_ptrace_clnt_call ();	/* Forward decl */
@@ -243,9 +243,9 @@ vx_create_inferior (char *exec_file, char *args, char **env)
   /* Install inferior's terminal modes.  */
   target_terminal_inferior ();
 
-  stop_soon_quietly = 1;
+  stop_soon_quietly = STOP_QUIETLY;
   wait_for_inferior ();		/* Get the task spawn event */
-  stop_soon_quietly = 0;
+  stop_soon_quietly = NO_STOP_QUIETLY;
 
   /* insert_step_breakpoint ();  FIXME, do we need this?  */
   proceed (-1, TARGET_SIGNAL_DEFAULT, 0);

gdb/solib-irix.c

@@ -436,7 +436,7 @@ irix_solib_create_inferior_hook (void)
      out what we need to know about them. */
 
   clear_proceed_status ();
-  stop_soon_quietly = 1;
+  stop_soon_quietly = STOP_QUIETLY;
   stop_signal = TARGET_SIGNAL_0;
   do
     {
@@ -462,7 +462,7 @@ irix_solib_create_inferior_hook (void)
      Delaying the resetting of stop_soon_quietly until after symbol loading
      suppresses the warning.  */
   solib_add ((char *) 0, 0, (struct target_ops *) 0, auto_solib_add);
-  stop_soon_quietly = 0;
+  stop_soon_quietly = NO_STOP_QUIETLY;
   re_enable_breakpoints_in_shlibs ();
 }
 

gdb/solib-osf.c

@@ -321,7 +321,7 @@ osf_solib_create_inferior_hook (void)
      out what we need to know about them. */
 
   clear_proceed_status ();
-  stop_soon_quietly = 1;
+  stop_soon_quietly = STOP_QUIETLY;
   stop_signal = TARGET_SIGNAL_0;
   do
     {
@@ -337,7 +337,7 @@ osf_solib_create_inferior_hook (void)
      Delaying the resetting of stop_soon_quietly until after symbol loading
      suppresses the warning.  */
   solib_add ((char *) 0, 0, (struct target_ops *) 0, auto_solib_add);
-  stop_soon_quietly = 0;
+  stop_soon_quietly = NO_STOP_QUIETLY;
 
   /* Enable breakpoints disabled (unnecessarily) by clear_solib().  */
   re_enable_breakpoints_in_shlibs ();

gdb/solib-sunos.c

@@ -829,7 +829,7 @@ sunos_solib_create_inferior_hook (void)
      out what we need to know about them. */
 
   clear_proceed_status ();
-  stop_soon_quietly = 1;
+  stop_soon_quietly = STOP_QUIETLY;
   stop_signal = TARGET_SIGNAL_0;
   do
     {
@@ -837,7 +837,7 @@ sunos_solib_create_inferior_hook (void)
       wait_for_inferior ();
     }
   while (stop_signal != TARGET_SIGNAL_TRAP);
-  stop_soon_quietly = 0;
+  stop_soon_quietly = NO_STOP_QUIETLY;
 
   /* We are now either at the "mapping complete" breakpoint (or somewhere
      else, a condition we aren't prepared to deal with anyway), so adjust

gdb/solib-svr4.c

@@ -1290,7 +1290,7 @@ svr4_solib_create_inferior_hook (void)
      out what we need to know about them. */
 
   clear_proceed_status ();
-  stop_soon_quietly = 1;
+  stop_soon_quietly = STOP_QUIETLY;
   stop_signal = TARGET_SIGNAL_0;
   do
     {
@@ -1298,7 +1298,7 @@ svr4_solib_create_inferior_hook (void)
       wait_for_inferior ();
     }
   while (stop_signal != TARGET_SIGNAL_TRAP);
-  stop_soon_quietly = 0;
+  stop_soon_quietly = NO_STOP_QUIETLY;
 #endif /* defined(_SCO_DS) */
 }