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, 2010, 2011 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 53 /* Any generic error, the corresponding text is in 54 exception.message. */ 55 GENERIC_ERROR, 56 57 /* Something requested was not found. */ 58 NOT_FOUND_ERROR, 59 60 /* Thread library lacks support necessary for finding thread local 61 storage. */ 62 TLS_NO_LIBRARY_SUPPORT_ERROR, 63 64 /* Load module not found while attempting to find thread local storage. */ 65 TLS_LOAD_MODULE_NOT_FOUND_ERROR, 66 67 /* Thread local storage has not been allocated yet. */ 68 TLS_NOT_ALLOCATED_YET_ERROR, 69 70 /* Something else went wrong while attempting to find thread local 71 storage. The ``struct gdb_exception'' message field provides 72 more detail. */ 73 TLS_GENERIC_ERROR, 74 75 /* Problem parsing an XML document. */ 76 XML_PARSE_ERROR, 77 78 /* Error accessing memory. */ 79 MEMORY_ERROR, 80 81 /* Feature is not supported in this copy of GDB. */ 82 UNSUPPORTED_ERROR, 83 84 /* Value not available. E.g., a register was not collected in a 85 traceframe. */ 86 NOT_AVAILABLE_ERROR, 87 88 /* Add more errors here. */ 89 NR_ERRORS 90 }; 91 92 struct gdb_exception 93 { 94 enum return_reason reason; 95 enum errors error; 96 const char *message; 97 }; 98 99 /* A pre-defined non-exception. */ 100 extern const struct gdb_exception exception_none; 101 102 /* Wrap set/long jmp so that it's more portable (internal to 103 exceptions). */ 104 105 #if defined(HAVE_SIGSETJMP) 106 #define EXCEPTIONS_SIGJMP_BUF sigjmp_buf 107 #define EXCEPTIONS_SIGSETJMP(buf) sigsetjmp((buf), 1) 108 #define EXCEPTIONS_SIGLONGJMP(buf,val) siglongjmp((buf), (val)) 109 #else 110 #define EXCEPTIONS_SIGJMP_BUF jmp_buf 111 #define EXCEPTIONS_SIGSETJMP(buf) setjmp(buf) 112 #define EXCEPTIONS_SIGLONGJMP(buf,val) longjmp((buf), (val)) 113 #endif 114 115 /* Functions to drive the exceptions state m/c (internal to 116 exceptions). */ 117 EXCEPTIONS_SIGJMP_BUF *exceptions_state_mc_init (struct ui_out *func_uiout, 118 volatile struct 119 gdb_exception *exception, 120 return_mask mask); 121 int exceptions_state_mc_action_iter (void); 122 int exceptions_state_mc_action_iter_1 (void); 123 124 /* Macro to wrap up standard try/catch behavior. 125 126 The double loop lets us correctly handle code "break"ing out of the 127 try catch block. (It works as the "break" only exits the inner 128 "while" loop, the outer for loop detects this handling it 129 correctly.) Of course "return" and "goto" are not so lucky. 130 131 For instance: 132 133 *INDENT-OFF* 134 135 volatile struct gdb_exception e; 136 TRY_CATCH (e, RETURN_MASK_ERROR) 137 { 138 } 139 switch (e.reason) 140 { 141 case RETURN_ERROR: ... 142 } 143 144 */ 145 146 #define TRY_CATCH(EXCEPTION,MASK) \ 147 { \ 148 EXCEPTIONS_SIGJMP_BUF *buf = \ 149 exceptions_state_mc_init (uiout, &(EXCEPTION), (MASK)); \ 150 EXCEPTIONS_SIGSETJMP (*buf); \ 151 } \ 152 while (exceptions_state_mc_action_iter ()) \ 153 while (exceptions_state_mc_action_iter_1 ()) 154 155 /* *INDENT-ON* */ 156 157 158 /* If E is an exception, print it's error message on the specified 159 stream. For _fprintf, prefix the message with PREFIX... */ 160 extern void exception_print (struct ui_file *file, struct gdb_exception e); 161 extern void exception_fprintf (struct ui_file *file, struct gdb_exception e, 162 const char *prefix, 163 ...) ATTRIBUTE_PRINTF (3, 4); 164 165 /* Throw an exception (as described by "struct gdb_exception"). Will 166 execute a LONG JUMP to the inner most containing exception handler 167 established using catch_exceptions() (or similar). 168 169 Code normally throws an exception using error() et.al. For various 170 reaons, GDB also contains code that throws an exception directly. 171 For instance, the remote*.c targets contain CNTRL-C signal handlers 172 that propogate the QUIT event up the exception chain. ``This could 173 be a good thing or a dangerous thing.'' -- the Existential 174 Wombat. */ 175 176 extern void throw_exception (struct gdb_exception exception) 177 ATTRIBUTE_NORETURN; 178 extern void throw_verror (enum errors, const char *fmt, va_list ap) 179 ATTRIBUTE_NORETURN ATTRIBUTE_PRINTF (2, 0); 180 extern void throw_vfatal (const char *fmt, va_list ap) 181 ATTRIBUTE_NORETURN ATTRIBUTE_PRINTF (1, 0); 182 extern void throw_error (enum errors error, const char *fmt, ...) 183 ATTRIBUTE_NORETURN ATTRIBUTE_PRINTF (2, 3); 184 185 /* Instead of deprecated_throw_reason, code should use catch_exception 186 and throw_exception. */ 187 extern void deprecated_throw_reason (enum return_reason reason) 188 ATTRIBUTE_NORETURN; 189 190 /* Call FUNC(UIOUT, FUNC_ARGS) but wrapped within an exception 191 handler. If an exception (enum return_reason) is thrown using 192 throw_exception() than all cleanups installed since 193 catch_exceptions() was entered are invoked, the (-ve) exception 194 value is then returned by catch_exceptions. If FUNC() returns 195 normally (with a positive or zero return value) then that value is 196 returned by catch_exceptions(). It is an internal_error() for 197 FUNC() to return a negative value. 198 199 For the period of the FUNC() call: UIOUT is installed as the output 200 builder; ERRSTRING is installed as the error/quit message; and a 201 new cleanup_chain is established. The old values are restored 202 before catch_exceptions() returns. 203 204 The variant catch_exceptions_with_msg() is the same as 205 catch_exceptions() but adds the ability to return an allocated 206 copy of the gdb error message. This is used when a silent error is 207 issued and the caller wants to manually issue the error message. 208 209 MASK specifies what to catch; it is normally set to 210 RETURN_MASK_ALL, if for no other reason than that the code which 211 calls catch_errors might not be set up to deal with a quit which 212 isn't caught. But if the code can deal with it, it generally 213 should be RETURN_MASK_ERROR, unless for some reason it is more 214 useful to abort only the portion of the operation inside the 215 catch_errors. Note that quit should return to the command line 216 fairly quickly, even if some further processing is being done. 217 218 FIXME; cagney/2001-08-13: The need to override the global UIOUT 219 builder variable should just go away. 220 221 This function supersedes catch_errors(). 222 223 This function uses SETJMP() and LONGJUMP(). */ 224 225 struct ui_out; 226 typedef int (catch_exceptions_ftype) (struct ui_out *ui_out, void *args); 227 extern int catch_exceptions (struct ui_out *uiout, 228 catch_exceptions_ftype *func, void *func_args, 229 return_mask mask); 230 typedef void (catch_exception_ftype) (struct ui_out *ui_out, void *args); 231 extern int catch_exceptions_with_msg (struct ui_out *uiout, 232 catch_exceptions_ftype *func, 233 void *func_args, 234 char **gdberrmsg, 235 return_mask mask); 236 237 /* This function, in addition, suppresses the printing of the captured 238 error message. It's up to the client to print it. */ 239 240 extern struct gdb_exception catch_exception (struct ui_out *uiout, 241 catch_exception_ftype *func, 242 void *func_args, 243 return_mask mask); 244 245 /* If CATCH_ERRORS_FTYPE throws an error, catch_errors() returns zero 246 otherwize the result from CATCH_ERRORS_FTYPE is returned. It is 247 probably useful for CATCH_ERRORS_FTYPE to always return a non-zero 248 value. It's unfortunate that, catch_errors() does not return an 249 indication of the exact exception that it caught - quit_flag might 250 help. 251 252 This function is superseded by catch_exceptions(). */ 253 254 typedef int (catch_errors_ftype) (void *); 255 extern int catch_errors (catch_errors_ftype *, void *, char *, return_mask); 256 257 /* Template to catch_errors() that wraps calls to command 258 functions. */ 259 260 typedef void (catch_command_errors_ftype) (char *, int); 261 extern int catch_command_errors (catch_command_errors_ftype *func, 262 char *command, int from_tty, return_mask); 263 264 #endif 265