1 /* Exception (throw catch) mechanism, for GDB, the GNU debugger. 2 3 Copyright (C) 1986-2013 Free Software Foundation, Inc. 4 5 This file is part of GDB. 6 7 This program is free software; you can redistribute it and/or modify 8 it under the terms of the GNU General Public License as published by 9 the Free Software Foundation; either version 3 of the License, or 10 (at your option) any later version. 11 12 This program is distributed in the hope that it will be useful, 13 but WITHOUT ANY WARRANTY; without even the implied warranty of 14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 15 GNU General Public License for more details. 16 17 You should have received a copy of the GNU General Public License 18 along with this program. If not, see <http://www.gnu.org/licenses/>. */ 19 20 #ifndef EXCEPTIONS_H 21 #define EXCEPTIONS_H 22 23 #include "ui-out.h" 24 #include <setjmp.h> 25 26 /* Reasons for calling throw_exceptions(). NOTE: all reason values 27 must be less than zero. enum value 0 is reserved for internal use 28 as the return value from an initial setjmp(). The function 29 catch_exceptions() reserves values >= 0 as legal results from its 30 wrapped function. */ 31 32 enum return_reason 33 { 34 /* User interrupt. */ 35 RETURN_QUIT = -2, 36 /* Any other error. */ 37 RETURN_ERROR 38 }; 39 40 #define RETURN_MASK(reason) (1 << (int)(-reason)) 41 #define RETURN_MASK_QUIT RETURN_MASK (RETURN_QUIT) 42 #define RETURN_MASK_ERROR RETURN_MASK (RETURN_ERROR) 43 #define RETURN_MASK_ALL (RETURN_MASK_QUIT | RETURN_MASK_ERROR) 44 typedef int return_mask; 45 46 /* Describe all exceptions. */ 47 48 enum errors { 49 GDB_NO_ERROR, 50 51 /* Any generic error, the corresponding text is in 52 exception.message. */ 53 GENERIC_ERROR, 54 55 /* Something requested was not found. */ 56 NOT_FOUND_ERROR, 57 58 /* Thread library lacks support necessary for finding thread local 59 storage. */ 60 TLS_NO_LIBRARY_SUPPORT_ERROR, 61 62 /* Load module not found while attempting to find thread local storage. */ 63 TLS_LOAD_MODULE_NOT_FOUND_ERROR, 64 65 /* Thread local storage has not been allocated yet. */ 66 TLS_NOT_ALLOCATED_YET_ERROR, 67 68 /* Something else went wrong while attempting to find thread local 69 storage. The ``struct gdb_exception'' message field provides 70 more detail. */ 71 TLS_GENERIC_ERROR, 72 73 /* Problem parsing an XML document. */ 74 XML_PARSE_ERROR, 75 76 /* Error accessing memory. */ 77 MEMORY_ERROR, 78 79 /* Feature is not supported in this copy of GDB. */ 80 UNSUPPORTED_ERROR, 81 82 /* Value not available. E.g., a register was not collected in a 83 traceframe. */ 84 NOT_AVAILABLE_ERROR, 85 86 /* DW_OP_GNU_entry_value resolving failed. */ 87 NO_ENTRY_VALUE_ERROR, 88 89 /* Target throwing an error has been closed. Current command should be 90 aborted as the inferior state is no longer valid. */ 91 TARGET_CLOSE_ERROR, 92 93 /* Add more errors here. */ 94 NR_ERRORS 95 }; 96 97 struct gdb_exception 98 { 99 enum return_reason reason; 100 enum errors error; 101 const char *message; 102 }; 103 104 /* A pre-defined non-exception. */ 105 extern const struct gdb_exception exception_none; 106 107 /* Wrap set/long jmp so that it's more portable (internal to 108 exceptions). */ 109 110 #if defined(HAVE_SIGSETJMP) 111 #define EXCEPTIONS_SIGJMP_BUF sigjmp_buf 112 #define EXCEPTIONS_SIGSETJMP(buf) sigsetjmp((buf), 1) 113 #define EXCEPTIONS_SIGLONGJMP(buf,val) siglongjmp((buf), (val)) 114 #else 115 #define EXCEPTIONS_SIGJMP_BUF jmp_buf 116 #define EXCEPTIONS_SIGSETJMP(buf) setjmp(buf) 117 #define EXCEPTIONS_SIGLONGJMP(buf,val) longjmp((buf), (val)) 118 #endif 119 120 /* Functions to drive the exceptions state m/c (internal to 121 exceptions). */ 122 EXCEPTIONS_SIGJMP_BUF *exceptions_state_mc_init (volatile struct 123 gdb_exception *exception, 124 return_mask mask); 125 int exceptions_state_mc_action_iter (void); 126 int exceptions_state_mc_action_iter_1 (void); 127 128 /* Macro to wrap up standard try/catch behavior. 129 130 The double loop lets us correctly handle code "break"ing out of the 131 try catch block. (It works as the "break" only exits the inner 132 "while" loop, the outer for loop detects this handling it 133 correctly.) Of course "return" and "goto" are not so lucky. 134 135 For instance: 136 137 *INDENT-OFF* 138 139 volatile struct gdb_exception e; 140 TRY_CATCH (e, RETURN_MASK_ERROR) 141 { 142 } 143 switch (e.reason) 144 { 145 case RETURN_ERROR: ... 146 } 147 148 */ 149 150 #define TRY_CATCH(EXCEPTION,MASK) \ 151 { \ 152 EXCEPTIONS_SIGJMP_BUF *buf = \ 153 exceptions_state_mc_init (&(EXCEPTION), (MASK)); \ 154 EXCEPTIONS_SIGSETJMP (*buf); \ 155 } \ 156 while (exceptions_state_mc_action_iter ()) \ 157 while (exceptions_state_mc_action_iter_1 ()) 158 159 /* *INDENT-ON* */ 160 161 162 /* If E is an exception, print it's error message on the specified 163 stream. For _fprintf, prefix the message with PREFIX... */ 164 extern void exception_print (struct ui_file *file, struct gdb_exception e); 165 extern void exception_fprintf (struct ui_file *file, struct gdb_exception e, 166 const char *prefix, 167 ...) ATTRIBUTE_PRINTF (3, 4); 168 169 /* Throw an exception (as described by "struct gdb_exception"). Will 170 execute a LONG JUMP to the inner most containing exception handler 171 established using catch_exceptions() (or similar). 172 173 Code normally throws an exception using error() et.al. For various 174 reaons, GDB also contains code that throws an exception directly. 175 For instance, the remote*.c targets contain CNTRL-C signal handlers 176 that propogate the QUIT event up the exception chain. ``This could 177 be a good thing or a dangerous thing.'' -- the Existential 178 Wombat. */ 179 180 extern void throw_exception (struct gdb_exception exception) 181 ATTRIBUTE_NORETURN; 182 extern void throw_verror (enum errors, const char *fmt, va_list ap) 183 ATTRIBUTE_NORETURN ATTRIBUTE_PRINTF (2, 0); 184 extern void throw_vfatal (const char *fmt, va_list ap) 185 ATTRIBUTE_NORETURN ATTRIBUTE_PRINTF (1, 0); 186 extern void throw_error (enum errors error, const char *fmt, ...) 187 ATTRIBUTE_NORETURN ATTRIBUTE_PRINTF (2, 3); 188 189 /* Instead of deprecated_throw_reason, code should use 190 throw_exception. */ 191 extern void deprecated_throw_reason (enum return_reason reason) 192 ATTRIBUTE_NORETURN; 193 194 /* Call FUNC(UIOUT, FUNC_ARGS) but wrapped within an exception 195 handler. If an exception (enum return_reason) is thrown using 196 throw_exception() than all cleanups installed since 197 catch_exceptions() was entered are invoked, the (-ve) exception 198 value is then returned by catch_exceptions. If FUNC() returns 199 normally (with a positive or zero return value) then that value is 200 returned by catch_exceptions(). It is an internal_error() for 201 FUNC() to return a negative value. 202 203 For the period of the FUNC() call: UIOUT is installed as the output 204 builder; ERRSTRING is installed as the error/quit message; and a 205 new cleanup_chain is established. The old values are restored 206 before catch_exceptions() returns. 207 208 The variant catch_exceptions_with_msg() is the same as 209 catch_exceptions() but adds the ability to return an allocated 210 copy of the gdb error message. This is used when a silent error is 211 issued and the caller wants to manually issue the error message. 212 213 MASK specifies what to catch; it is normally set to 214 RETURN_MASK_ALL, if for no other reason than that the code which 215 calls catch_errors might not be set up to deal with a quit which 216 isn't caught. But if the code can deal with it, it generally 217 should be RETURN_MASK_ERROR, unless for some reason it is more 218 useful to abort only the portion of the operation inside the 219 catch_errors. Note that quit should return to the command line 220 fairly quickly, even if some further processing is being done. 221 222 FIXME; cagney/2001-08-13: The need to override the global UIOUT 223 builder variable should just go away. 224 225 This function supersedes catch_errors(). 226 227 This function uses SETJMP() and LONGJUMP(). */ 228 229 struct ui_out; 230 typedef int (catch_exceptions_ftype) (struct ui_out *ui_out, void *args); 231 extern int catch_exceptions (struct ui_out *uiout, 232 catch_exceptions_ftype *func, void *func_args, 233 return_mask mask); 234 typedef void (catch_exception_ftype) (struct ui_out *ui_out, void *args); 235 extern int catch_exceptions_with_msg (struct ui_out *uiout, 236 catch_exceptions_ftype *func, 237 void *func_args, 238 char **gdberrmsg, 239 return_mask mask); 240 241 /* If CATCH_ERRORS_FTYPE throws an error, catch_errors() returns zero 242 otherwize the result from CATCH_ERRORS_FTYPE is returned. It is 243 probably useful for CATCH_ERRORS_FTYPE to always return a non-zero 244 value. It's unfortunate that, catch_errors() does not return an 245 indication of the exact exception that it caught - quit_flag might 246 help. 247 248 This function is superseded by catch_exceptions(). */ 249 250 typedef int (catch_errors_ftype) (void *); 251 extern int catch_errors (catch_errors_ftype *, void *, char *, return_mask); 252 253 /* Template to catch_errors() that wraps calls to command 254 functions. */ 255 256 typedef void (catch_command_errors_ftype) (char *, int); 257 extern int catch_command_errors (catch_command_errors_ftype *func, 258 char *command, int from_tty, return_mask); 259 260 #endif 261