1 /* Exception (throw catch) mechanism, for GDB, the GNU debugger. 2 3 Copyright (C) 1986, 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 4 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 5 2009 Free 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 3 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, see <http://www.gnu.org/licenses/>. */ 21 22 #ifndef EXCEPTIONS_H 23 #define EXCEPTIONS_H 24 25 #include "ui-out.h" 26 #include <setjmp.h> 27 28 /* Reasons for calling throw_exceptions(). NOTE: all reason values 29 must be less than zero. enum value 0 is reserved for internal use 30 as the return value from an initial setjmp(). The function 31 catch_exceptions() reserves values >= 0 as legal results from its 32 wrapped function. */ 33 34 enum return_reason 35 { 36 /* User interrupt. */ 37 RETURN_QUIT = -2, 38 /* Any other error. */ 39 RETURN_ERROR 40 }; 41 42 #define RETURN_MASK(reason) (1 << (int)(-reason)) 43 #define RETURN_MASK_QUIT RETURN_MASK (RETURN_QUIT) 44 #define RETURN_MASK_ERROR RETURN_MASK (RETURN_ERROR) 45 #define RETURN_MASK_ALL (RETURN_MASK_QUIT | RETURN_MASK_ERROR) 46 typedef int return_mask; 47 48 /* Describe all exceptions. */ 49 50 enum errors { 51 GDB_NO_ERROR, 52 /* Any generic error, the corresponding text is in 53 exception.message. */ 54 GENERIC_ERROR, 55 NOT_FOUND_ERROR, 56 57 /* Thread library lacks support necessary for finding thread local 58 storage. */ 59 TLS_NO_LIBRARY_SUPPORT_ERROR, 60 61 /* Load module not found while attempting to find thread local storage. */ 62 TLS_LOAD_MODULE_NOT_FOUND_ERROR, 63 64 /* Thread local storage has not been allocated yet. */ 65 TLS_NOT_ALLOCATED_YET_ERROR, 66 67 /* Something else went wrong while attempting to find thread local 68 storage. The ``struct gdb_exception'' message field provides 69 more detail. */ 70 TLS_GENERIC_ERROR, 71 72 /* Problem parsing an XML document. */ 73 XML_PARSE_ERROR, 74 75 /* Error accessing memory. */ 76 MEMORY_ERROR, 77 78 /* Add more errors here. */ 79 NR_ERRORS 80 }; 81 82 struct gdb_exception 83 { 84 enum return_reason reason; 85 enum errors error; 86 const char *message; 87 }; 88 89 /* A pre-defined non-exception. */ 90 extern const struct gdb_exception exception_none; 91 92 /* Wrap set/long jmp so that it's more portable (internal to 93 exceptions). */ 94 95 #if defined(HAVE_SIGSETJMP) 96 #define EXCEPTIONS_SIGJMP_BUF sigjmp_buf 97 #define EXCEPTIONS_SIGSETJMP(buf) sigsetjmp((buf), 1) 98 #define EXCEPTIONS_SIGLONGJMP(buf,val) siglongjmp((buf), (val)) 99 #else 100 #define EXCEPTIONS_SIGJMP_BUF jmp_buf 101 #define EXCEPTIONS_SIGSETJMP(buf) setjmp(buf) 102 #define EXCEPTIONS_SIGLONGJMP(buf,val) longjmp((buf), (val)) 103 #endif 104 105 /* Functions to drive the exceptions state m/c (internal to 106 exceptions). */ 107 EXCEPTIONS_SIGJMP_BUF *exceptions_state_mc_init (struct ui_out *func_uiout, 108 volatile struct gdb_exception * 109 exception, 110 return_mask mask); 111 int exceptions_state_mc_action_iter (void); 112 int exceptions_state_mc_action_iter_1 (void); 113 114 /* Macro to wrap up standard try/catch behavior. 115 116 The double loop lets us correctly handle code "break"ing out of the 117 try catch block. (It works as the "break" only exits the inner 118 "while" loop, the outer for loop detects this handling it 119 correctly.) Of course "return" and "goto" are not so lucky. 120 121 For instance: 122 123 *INDENT-OFF* 124 125 volatile struct gdb_exception e; 126 TRY_CATCH (e, RETURN_MASK_ERROR) 127 { 128 } 129 switch (e.reason) 130 { 131 case RETURN_ERROR: ... 132 } 133 134 */ 135 136 #define TRY_CATCH(EXCEPTION,MASK) \ 137 { \ 138 EXCEPTIONS_SIGJMP_BUF *buf = \ 139 exceptions_state_mc_init (uiout, &(EXCEPTION), (MASK)); \ 140 EXCEPTIONS_SIGSETJMP (*buf); \ 141 } \ 142 while (exceptions_state_mc_action_iter ()) \ 143 while (exceptions_state_mc_action_iter_1 ()) 144 145 /* *INDENT-ON* */ 146 147 148 /* If E is an exception, print it's error message on the specified 149 stream. for _fprintf, prefix the message with PREFIX... */ 150 extern void exception_print (struct ui_file *file, struct gdb_exception e); 151 extern void exception_fprintf (struct ui_file *file, struct gdb_exception e, 152 const char *prefix, 153 ...) ATTR_FORMAT (printf, 3, 4); 154 155 /* Throw an exception (as described by "struct gdb_exception"). Will 156 execute a LONG JUMP to the inner most containing exception handler 157 established using catch_exceptions() (or similar). 158 159 Code normally throws an exception using error() et.al. For various 160 reaons, GDB also contains code that throws an exception directly. 161 For instance, the remote*.c targets contain CNTRL-C signal handlers 162 that propogate the QUIT event up the exception chain. ``This could 163 be a good thing or a dangerous thing.'' -- the Existential 164 Wombat. */ 165 166 extern NORETURN void throw_exception (struct gdb_exception exception) ATTR_NORETURN; 167 extern NORETURN void throw_verror (enum errors, const char *fmt, va_list ap) 168 ATTR_NORETURN ATTR_FORMAT (printf, 2, 0); 169 extern NORETURN void throw_vfatal (const char *fmt, va_list ap) 170 ATTR_NORETURN ATTR_FORMAT (printf, 1, 0); 171 extern NORETURN void throw_error (enum errors error, const char *fmt, 172 ...) ATTR_NORETURN ATTR_FORMAT (printf, 2, 3); 173 174 /* Instead of deprecated_throw_reason, code should use catch_exception 175 and throw_exception. */ 176 extern NORETURN void deprecated_throw_reason (enum return_reason reason) ATTR_NORETURN; 177 178 /* Call FUNC(UIOUT, FUNC_ARGS) but wrapped within an exception 179 handler. If an exception (enum return_reason) is thrown using 180 throw_exception() than all cleanups installed since 181 catch_exceptions() was entered are invoked, the (-ve) exception 182 value is then returned by catch_exceptions. If FUNC() returns 183 normally (with a positive or zero return value) then that value is 184 returned by catch_exceptions(). It is an internal_error() for 185 FUNC() to return a negative value. 186 187 For the period of the FUNC() call: UIOUT is installed as the output 188 builder; ERRSTRING is installed as the error/quit message; and a 189 new cleanup_chain is established. The old values are restored 190 before catch_exceptions() returns. 191 192 The variant catch_exceptions_with_msg() is the same as 193 catch_exceptions() but adds the ability to return an allocated 194 copy of the gdb error message. This is used when a silent error is 195 issued and the caller wants to manually issue the error message. 196 197 MASK specifies what to catch; it is normally set to 198 RETURN_MASK_ALL, if for no other reason than that the code which 199 calls catch_errors might not be set up to deal with a quit which 200 isn't caught. But if the code can deal with it, it generally 201 should be RETURN_MASK_ERROR, unless for some reason it is more 202 useful to abort only the portion of the operation inside the 203 catch_errors. Note that quit should return to the command line 204 fairly quickly, even if some further processing is being done. 205 206 FIXME; cagney/2001-08-13: The need to override the global UIOUT 207 builder variable should just go away. 208 209 This function supersedes catch_errors(). 210 211 This function uses SETJMP() and LONGJUMP(). */ 212 213 struct ui_out; 214 typedef int (catch_exceptions_ftype) (struct ui_out *ui_out, void *args); 215 extern int catch_exceptions (struct ui_out *uiout, 216 catch_exceptions_ftype *func, void *func_args, 217 return_mask mask); 218 typedef void (catch_exception_ftype) (struct ui_out *ui_out, void *args); 219 extern int catch_exceptions_with_msg (struct ui_out *uiout, 220 catch_exceptions_ftype *func, 221 void *func_args, 222 char **gdberrmsg, 223 return_mask mask); 224 225 /* This function, in addition, suppresses the printing of the captured 226 error message. It's up to the client to print it. */ 227 228 extern struct gdb_exception catch_exception (struct ui_out *uiout, 229 catch_exception_ftype *func, 230 void *func_args, 231 return_mask mask); 232 233 /* If CATCH_ERRORS_FTYPE throws an error, catch_errors() returns zero 234 otherwize the result from CATCH_ERRORS_FTYPE is returned. It is 235 probably useful for CATCH_ERRORS_FTYPE to always return a non-zero 236 value. It's unfortunate that, catch_errors() does not return an 237 indication of the exact exception that it caught - quit_flag might 238 help. 239 240 This function is superseded by catch_exceptions(). */ 241 242 typedef int (catch_errors_ftype) (void *); 243 extern int catch_errors (catch_errors_ftype *, void *, char *, return_mask); 244 245 /* Template to catch_errors() that wraps calls to command 246 functions. */ 247 248 typedef void (catch_command_errors_ftype) (char *, int); 249 extern int catch_command_errors (catch_command_errors_ftype *func, char *command, int from_tty, return_mask); 250 251 #endif 252