* Introduced pipes in the kernel debugger. The syntax is similar to

pipes in the shell, though the semantics is a little different: The
  second command is invoked whenever the first command has written a
  complete line. The line is passed as last argument to the second
  command. The new command flag B_KDEBUG_PIPE_FINAL_RERUN causes the
  second command to be invoked again (with NULL argument) after the
  first command is done.
* Added kprintf_unfiltered() and kputs_unfiltered() which bypass the
  pipe mechanism and directly print to the bluescreen/serial output.
* Moved most commands from debug.cpp to the new
  debug_builtin_commands.cpp.
* B_KDEBUG_DONT_PARSE_ARGUMENTS commands don't get an argument anymore,
  if it would consist of white space only.
* Added new debugger command return value B_KDEBUG_ERROR, which
  indicates that executing the command failed. This return code will
  abort a complete pipe.
* Since debugger commands can nest (i.e. one command can invoke another
  one) the setjmp()/longjmp() mechanism to restore the stack after a
  page fault in a command needs more than one jump buffer.
* Added abort_debugger_command(), which longjmp()s out of the currently
  executed command. This will also abort the current pipe.
* When pagination is enabled pressing "a" will abort the running command
  (as opposed to "q" which only disables the blue screen output, but
  lets the command continue).
* Added debugger commands:
  - "grep" which can be used to filter output by pattern. Removed the
    "filter" command and the underlying mechanism that did that before.
  - "head" which prints only the first lines of output of another
    command.
  - "wc" counts lines, words, and characters of another command's
    output.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@25744 a95241bf-73f2-0310-859d-f6bbb57e9c96

headers/private/kernel/debug.h

@@ -42,7 +42,12 @@
 #	define ASSERT_PRINT(x, format...)	do { } while(0)
 #endif
 
+// command return value
+#define B_KDEBUG_ERROR	4
+
+// command flags
 #define B_KDEBUG_DONT_PARSE_ARGUMENTS	(0x01)
+#define B_KDEBUG_PIPE_FINAL_RERUN		(0x02)
 
 struct debugger_module_info {
 	module_info info;
@@ -74,6 +79,9 @@ extern bool debug_screen_output_enabled(void);
 extern void debug_stop_screen_debug_output(void);
 
 extern void	kputs(const char *string);
+extern void	kputs_unfiltered(const char *string);
+extern void kprintf_unfiltered(const char *format, ...)
+				__attribute__ ((format (__printf__, 1, 2)));
 extern void dprintf_no_syslog(const char *format, ...)
 				__attribute__ ((format (__printf__, 1, 2)));