/* Exception (throw catch) mechanism, for GDB, the GNU debugger. Copyright 1986, 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005 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. */ #ifndef EXCEPTIONS_H #define EXCEPTIONS_H #include "ui-out.h" #include <setjmp.h> /* Reasons for calling throw_exceptions(). NOTE: all reason values must be less than zero. enum value 0 is reserved for internal use as the return value from an initial setjmp(). The function catch_exceptions() reserves values >= 0 as legal results from its wrapped function. */ enum return_reason { /* User interrupt. */ RETURN_QUIT = -2, /* Any other error. */ RETURN_ERROR }; #define RETURN_MASK(reason) (1 << (int)(-reason)) #define RETURN_MASK_QUIT RETURN_MASK (RETURN_QUIT) #define RETURN_MASK_ERROR RETURN_MASK (RETURN_ERROR) #define RETURN_MASK_ALL (RETURN_MASK_QUIT | RETURN_MASK_ERROR) typedef int return_mask; /* Describe all exceptions. */ enum errors { NO_ERROR, /* Any generic error, the corresponding text is in exception.message. */ GENERIC_ERROR, NOT_FOUND_ERROR, /* Thread library lacks support necessary for finding thread local storage. */ TLS_NO_LIBRARY_SUPPORT_ERROR, /* Load module not found while attempting to find thread local storage. */ TLS_LOAD_MODULE_NOT_FOUND_ERROR, /* Thread local storage has not been allocated yet. */ TLS_NOT_ALLOCATED_YET_ERROR, /* Something else went wrong while attempting to find thread local storage. The ``struct gdb_exception'' message field provides more detail. */ TLS_GENERIC_ERROR, /* Add more errors here. */ NR_ERRORS }; struct gdb_exception { enum return_reason reason; enum errors error; const char *message; }; /* A pre-defined non-exception. */ extern const struct gdb_exception exception_none; /* Wrap set/long jmp so that it's more portable (internal to exceptions). */ #if defined(HAVE_SIGSETJMP) #define EXCEPTIONS_SIGJMP_BUF sigjmp_buf #define EXCEPTIONS_SIGSETJMP(buf) sigsetjmp((buf), 1) #define EXCEPTIONS_SIGLONGJMP(buf,val) siglongjmp((buf), (val)) #else #define EXCEPTIONS_SIGJMP_BUF jmp_buf #define EXCEPTIONS_SIGSETJMP(buf) setjmp(buf) #define EXCEPTIONS_SIGLONGJMP(buf,val) longjmp((buf), (val)) #endif /* Functions to drive the exceptions state m/c (internal to exceptions). */ EXCEPTIONS_SIGJMP_BUF *exceptions_state_mc_init (struct ui_out *func_uiout, volatile struct gdb_exception * exception, return_mask mask); int exceptions_state_mc_action_iter (void); int exceptions_state_mc_action_iter_1 (void); /* Macro to wrap up standard try/catch behavior. The double loop lets us correctly handle code "break"ing out of the try catch block. (It works as the "break" only exits the inner "while" loop, the outer for loop detects this handling it correctly.) Of course "return" and "goto" are not so lucky. For instance: *INDENT-OFF* volatile struct gdb_exception e; TRY_CATCH (e, RETURN_MASK_ERROR) { } switch (e.reason) { case RETURN_ERROR: ... } */ #define TRY_CATCH(EXCEPTION,MASK) \ { \ EXCEPTIONS_SIGJMP_BUF *buf = \ exceptions_state_mc_init (uiout, &(EXCEPTION), (MASK)); \ EXCEPTIONS_SIGSETJMP (*buf); \ } \ while (exceptions_state_mc_action_iter ()) \ while (exceptions_state_mc_action_iter_1 ()) /* *INDENT-ON* */ /* If E is an exception, print it's error message on the specified stream. for _fprintf, prefix the message with PREFIX... */ extern void exception_print (struct ui_file *file, struct gdb_exception e); extern void exception_fprintf (struct ui_file *file, struct gdb_exception e, const char *prefix, ...) ATTR_FORMAT (printf, 3, 4); /* Throw an exception (as described by "struct gdb_exception"). Will execute a LONG JUMP to the inner most containing exception handler established using catch_exceptions() (or similar). Code normally throws an exception using error() et.al. For various reaons, GDB also contains code that throws an exception directly. For instance, the remote*.c targets contain CNTRL-C signal handlers that propogate the QUIT event up the exception chain. ``This could be a good thing or a dangerous thing.'' -- the Existential Wombat. */ extern NORETURN void throw_exception (struct gdb_exception exception) ATTR_NORETURN; extern NORETURN void throw_verror (enum errors, const char *fmt, va_list ap) ATTR_NORETURN ATTR_FORMAT (printf, 2, 0); extern NORETURN void throw_vfatal (const char *fmt, va_list ap) ATTR_NORETURN ATTR_FORMAT (printf, 1, 0); extern NORETURN void throw_error (enum errors error, const char *fmt, ...) ATTR_NORETURN ATTR_FORMAT (printf, 2, 3); /* Instead of deprecated_throw_reason, code should use catch_exception and throw_exception. */ extern NORETURN void deprecated_throw_reason (enum return_reason reason) ATTR_NORETURN; /* Call FUNC(UIOUT, FUNC_ARGS) but wrapped within an exception handler. If an exception (enum return_reason) is thrown using throw_exception() than all cleanups installed since catch_exceptions() was entered are invoked, the (-ve) exception value is then returned by catch_exceptions. If FUNC() returns normally (with a postive or zero return value) then that value is returned by catch_exceptions(). It is an internal_error() for FUNC() to return a negative value. For the period of the FUNC() call: UIOUT is installed as the output builder; ERRSTRING is installed as the error/quit message; and a new cleanup_chain is established. The old values are restored before catch_exceptions() returns. The variant catch_exceptions_with_msg() is the same as catch_exceptions() but adds the ability to return an allocated copy of the gdb error message. This is used when a silent error is issued and the caller wants to manually issue the error message. FIXME; cagney/2001-08-13: The need to override the global UIOUT builder variable should just go away. This function superseeds catch_errors(). This function uses SETJMP() and LONGJUMP(). */ struct ui_out; typedef int (catch_exceptions_ftype) (struct ui_out *ui_out, void *args); extern int catch_exceptions (struct ui_out *uiout, catch_exceptions_ftype *func, void *func_args, return_mask mask); typedef void (catch_exception_ftype) (struct ui_out *ui_out, void *args); extern int catch_exceptions_with_msg (struct ui_out *uiout, catch_exceptions_ftype *func, void *func_args, char **gdberrmsg, return_mask mask); /* This function, in addition, suppresses the printing of the captured error message. It's up to the client to print it. */ extern struct gdb_exception catch_exception (struct ui_out *uiout, catch_exception_ftype *func, void *func_args, return_mask mask); /* If CATCH_ERRORS_FTYPE throws an error, catch_errors() returns zero otherwize the result from CATCH_ERRORS_FTYPE is returned. It is probably useful for CATCH_ERRORS_FTYPE to always return a non-zero value. It's unfortunate that, catch_errors() does not return an indication of the exact exception that it caught - quit_flag might help. This function is superseeded by catch_exceptions(). */ typedef int (catch_errors_ftype) (void *); extern int catch_errors (catch_errors_ftype *, void *, char *, return_mask); /* Template to catch_errors() that wraps calls to command functions. */ typedef void (catch_command_errors_ftype) (char *, int); extern int catch_command_errors (catch_command_errors_ftype *func, char *command, int from_tty, return_mask); #endif