1 /* Exception (throw catch) mechanism, for GDB, the GNU debugger. 2 3 Copyright 1986, 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 4 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005 Free 5 Software Foundation, Inc. 6 7 This file is part of GDB. 8 9 This program is free software; you can redistribute it and/or modify 10 it under the terms of the GNU General Public License as published by 11 the Free Software Foundation; either version 2 of the License, or 12 (at your option) any later version. 13 14 This program is distributed in the hope that it will be useful, 15 but WITHOUT ANY WARRANTY; without even the implied warranty of 16 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 17 GNU General Public License for more details. 18 19 You should have received a copy of the GNU General Public License 20 along with this program; if not, write to the Free Software 21 Foundation, Inc., 59 Temple Place - Suite 330, 22 Boston, MA 02111-1307, USA. */ 23 24 #ifndef EXCEPTIONS_H 25 #define EXCEPTIONS_H 26 27 #include "ui-out.h" 28 #include <setjmp.h> 29 30 /* Reasons for calling throw_exceptions(). NOTE: all reason values 31 must be less than zero. enum value 0 is reserved for internal use 32 as the return value from an initial setjmp(). The function 33 catch_exceptions() reserves values >= 0 as legal results from its 34 wrapped function. */ 35 36 enum return_reason 37 { 38 /* User interrupt. */ 39 RETURN_QUIT = -2, 40 /* Any other error. */ 41 RETURN_ERROR 42 }; 43 44 #define RETURN_MASK(reason) (1 << (int)(-reason)) 45 #define RETURN_MASK_QUIT RETURN_MASK (RETURN_QUIT) 46 #define RETURN_MASK_ERROR RETURN_MASK (RETURN_ERROR) 47 #define RETURN_MASK_ALL (RETURN_MASK_QUIT | RETURN_MASK_ERROR) 48 typedef int return_mask; 49 50 /* Describe all exceptions. */ 51 52 enum errors { 53 NO_ERROR, 54 /* Any generic error, the corresponding text is in 55 exception.message. */ 56 GENERIC_ERROR, 57 NOT_FOUND_ERROR, 58 59 /* Thread library lacks support necessary for finding thread local 60 storage. */ 61 TLS_NO_LIBRARY_SUPPORT_ERROR, 62 63 /* Load module not found while attempting to find thread local storage. */ 64 TLS_LOAD_MODULE_NOT_FOUND_ERROR, 65 66 /* Thread local storage has not been allocated yet. */ 67 TLS_NOT_ALLOCATED_YET_ERROR, 68 69 /* Something else went wrong while attempting to find thread local 70 storage. The ``struct gdb_exception'' message field provides 71 more detail. */ 72 TLS_GENERIC_ERROR, 73 74 /* Add more errors here. */ 75 NR_ERRORS 76 }; 77 78 struct gdb_exception 79 { 80 enum return_reason reason; 81 enum errors error; 82 const char *message; 83 }; 84 85 /* A pre-defined non-exception. */ 86 extern const struct gdb_exception exception_none; 87 88 /* Wrap set/long jmp so that it's more portable (internal to 89 exceptions). */ 90 91 #if defined(HAVE_SIGSETJMP) 92 #define EXCEPTIONS_SIGJMP_BUF sigjmp_buf 93 #define EXCEPTIONS_SIGSETJMP(buf) sigsetjmp((buf), 1) 94 #define EXCEPTIONS_SIGLONGJMP(buf,val) siglongjmp((buf), (val)) 95 #else 96 #define EXCEPTIONS_SIGJMP_BUF jmp_buf 97 #define EXCEPTIONS_SIGSETJMP(buf) setjmp(buf) 98 #define EXCEPTIONS_SIGLONGJMP(buf,val) longjmp((buf), (val)) 99 #endif 100 101 /* Functions to drive the exceptions state m/c (internal to 102 exceptions). */ 103 EXCEPTIONS_SIGJMP_BUF *exceptions_state_mc_init (struct ui_out *func_uiout, 104 volatile struct gdb_exception * 105 exception, 106 return_mask mask); 107 int exceptions_state_mc_action_iter (void); 108 int exceptions_state_mc_action_iter_1 (void); 109 110 /* Macro to wrap up standard try/catch behavior. 111 112 The double loop lets us correctly handle code "break"ing out of the 113 try catch block. (It works as the "break" only exits the inner 114 "while" loop, the outer for loop detects this handling it 115 correctly.) Of course "return" and "goto" are not so lucky. 116 117 For instance: 118 119 *INDENT-OFF* 120 121 volatile struct gdb_exception e; 122 TRY_CATCH (e, RETURN_MASK_ERROR) 123 { 124 } 125 switch (e.reason) 126 { 127 case RETURN_ERROR: ... 128 } 129 130 */ 131 132 #define TRY_CATCH(EXCEPTION,MASK) \ 133 { \ 134 EXCEPTIONS_SIGJMP_BUF *buf = \ 135 exceptions_state_mc_init (uiout, &(EXCEPTION), (MASK)); \ 136 EXCEPTIONS_SIGSETJMP (*buf); \ 137 } \ 138 while (exceptions_state_mc_action_iter ()) \ 139 while (exceptions_state_mc_action_iter_1 ()) 140 141 /* *INDENT-ON* */ 142 143 144 /* If E is an exception, print it's error message on the specified 145 stream. for _fprintf, prefix the message with PREFIX... */ 146 extern void exception_print (struct ui_file *file, struct gdb_exception e); 147 extern void exception_fprintf (struct ui_file *file, struct gdb_exception e, 148 const char *prefix, 149 ...) ATTR_FORMAT (printf, 3, 4); 150 151 /* Throw an exception (as described by "struct gdb_exception"). Will 152 execute a LONG JUMP to the inner most containing exception handler 153 established using catch_exceptions() (or similar). 154 155 Code normally throws an exception using error() et.al. For various 156 reaons, GDB also contains code that throws an exception directly. 157 For instance, the remote*.c targets contain CNTRL-C signal handlers 158 that propogate the QUIT event up the exception chain. ``This could 159 be a good thing or a dangerous thing.'' -- the Existential 160 Wombat. */ 161 162 extern NORETURN void throw_exception (struct gdb_exception exception) ATTR_NORETURN; 163 extern NORETURN void throw_verror (enum errors, const char *fmt, 164 va_list ap) ATTR_NORETURN; 165 extern NORETURN void throw_vfatal (const char *fmt, va_list ap) ATTR_NORETURN; 166 extern NORETURN void throw_error (enum errors error, const char *fmt, 167 ...) ATTR_NORETURN ATTR_FORMAT (printf, 2, 3); 168 169 /* Instead of deprecated_throw_reason, code should use catch_exception 170 and throw_exception. */ 171 extern NORETURN void deprecated_throw_reason (enum return_reason reason) ATTR_NORETURN; 172 173 /* Call FUNC(UIOUT, FUNC_ARGS) but wrapped within an exception 174 handler. If an exception (enum return_reason) is thrown using 175 throw_exception() than all cleanups installed since 176 catch_exceptions() was entered are invoked, the (-ve) exception 177 value is then returned by catch_exceptions. If FUNC() returns 178 normally (with a postive or zero return value) then that value is 179 returned by catch_exceptions(). It is an internal_error() for 180 FUNC() to return a negative value. 181 182 For the period of the FUNC() call: UIOUT is installed as the output 183 builder; ERRSTRING is installed as the error/quit message; and a 184 new cleanup_chain is established. The old values are restored 185 before catch_exceptions() returns. 186 187 The variant catch_exceptions_with_msg() is the same as 188 catch_exceptions() but adds the ability to return an allocated 189 copy of the gdb error message. This is used when a silent error is 190 issued and the caller wants to manually issue the error message. 191 192 FIXME; cagney/2001-08-13: The need to override the global UIOUT 193 builder variable should just go away. 194 195 This function superseeds catch_errors(). 196 197 This function uses SETJMP() and LONGJUMP(). */ 198 199 struct ui_out; 200 typedef int (catch_exceptions_ftype) (struct ui_out *ui_out, void *args); 201 extern int catch_exceptions (struct ui_out *uiout, 202 catch_exceptions_ftype *func, void *func_args, 203 return_mask mask); 204 typedef void (catch_exception_ftype) (struct ui_out *ui_out, void *args); 205 extern int catch_exceptions_with_msg (struct ui_out *uiout, 206 catch_exceptions_ftype *func, 207 void *func_args, 208 char **gdberrmsg, 209 return_mask mask); 210 211 /* This function, in addition, suppresses the printing of the captured 212 error message. It's up to the client to print it. */ 213 214 extern struct gdb_exception catch_exception (struct ui_out *uiout, 215 catch_exception_ftype *func, 216 void *func_args, 217 return_mask mask); 218 219 /* If CATCH_ERRORS_FTYPE throws an error, catch_errors() returns zero 220 otherwize the result from CATCH_ERRORS_FTYPE is returned. It is 221 probably useful for CATCH_ERRORS_FTYPE to always return a non-zero 222 value. It's unfortunate that, catch_errors() does not return an 223 indication of the exact exception that it caught - quit_flag might 224 help. 225 226 This function is superseeded by catch_exceptions(). */ 227 228 typedef int (catch_errors_ftype) (void *); 229 extern int catch_errors (catch_errors_ftype *, void *, char *, return_mask); 230 231 /* Template to catch_errors() that wraps calls to command 232 functions. */ 233 234 typedef void (catch_command_errors_ftype) (char *, int); 235 extern int catch_command_errors (catch_command_errors_ftype *func, char *command, int from_tty, return_mask); 236 237 #endif 238