1 /* Exception (throw catch) mechanism, for GDB, the GNU debugger. 2 3 Copyright (C) 1986-2014 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 42 typedef enum 43 { 44 RETURN_MASK_QUIT = RETURN_MASK (RETURN_QUIT), 45 RETURN_MASK_ERROR = RETURN_MASK (RETURN_ERROR), 46 RETURN_MASK_ALL = (RETURN_MASK_QUIT | RETURN_MASK_ERROR) 47 } return_mask; 48 49 /* Describe all exceptions. */ 50 51 enum errors { 52 GDB_NO_ERROR, 53 54 /* Any generic error, the corresponding text is in 55 exception.message. */ 56 GENERIC_ERROR, 57 58 /* Something requested was not found. */ 59 NOT_FOUND_ERROR, 60 61 /* Thread library lacks support necessary for finding thread local 62 storage. */ 63 TLS_NO_LIBRARY_SUPPORT_ERROR, 64 65 /* Load module not found while attempting to find thread local storage. */ 66 TLS_LOAD_MODULE_NOT_FOUND_ERROR, 67 68 /* Thread local storage has not been allocated yet. */ 69 TLS_NOT_ALLOCATED_YET_ERROR, 70 71 /* Something else went wrong while attempting to find thread local 72 storage. The ``struct gdb_exception'' message field provides 73 more detail. */ 74 TLS_GENERIC_ERROR, 75 76 /* Problem parsing an XML document. */ 77 XML_PARSE_ERROR, 78 79 /* Error accessing memory. */ 80 MEMORY_ERROR, 81 82 /* Value not available. E.g., a register was not collected in a 83 traceframe. */ 84 NOT_AVAILABLE_ERROR, 85 86 /* Value was optimized out. Note: if the value was a register, this 87 means the register was not saved in the frame. */ 88 OPTIMIZED_OUT_ERROR, 89 90 /* DW_OP_GNU_entry_value resolving failed. */ 91 NO_ENTRY_VALUE_ERROR, 92 93 /* Target throwing an error has been closed. Current command should be 94 aborted as the inferior state is no longer valid. */ 95 TARGET_CLOSE_ERROR, 96 97 /* An undefined command was executed. */ 98 UNDEFINED_COMMAND_ERROR, 99 100 /* Add more errors here. */ 101 NR_ERRORS 102 }; 103 104 struct gdb_exception 105 { 106 enum return_reason reason; 107 enum errors error; 108 const char *message; 109 }; 110 111 /* A pre-defined non-exception. */ 112 extern const struct gdb_exception exception_none; 113 114 /* Wrap set/long jmp so that it's more portable (internal to 115 exceptions). */ 116 117 #if defined(HAVE_SIGSETJMP) 118 #define EXCEPTIONS_SIGJMP_BUF sigjmp_buf 119 #define EXCEPTIONS_SIGSETJMP(buf) sigsetjmp((buf), 1) 120 #define EXCEPTIONS_SIGLONGJMP(buf,val) siglongjmp((buf), (val)) 121 #else 122 #define EXCEPTIONS_SIGJMP_BUF jmp_buf 123 #define EXCEPTIONS_SIGSETJMP(buf) setjmp(buf) 124 #define EXCEPTIONS_SIGLONGJMP(buf,val) longjmp((buf), (val)) 125 #endif 126 127 /* Functions to drive the exceptions state m/c (internal to 128 exceptions). */ 129 EXCEPTIONS_SIGJMP_BUF *exceptions_state_mc_init (volatile struct 130 gdb_exception *exception, 131 return_mask mask); 132 int exceptions_state_mc_action_iter (void); 133 int exceptions_state_mc_action_iter_1 (void); 134 135 /* Macro to wrap up standard try/catch behavior. 136 137 The double loop lets us correctly handle code "break"ing out of the 138 try catch block. (It works as the "break" only exits the inner 139 "while" loop, the outer for loop detects this handling it 140 correctly.) Of course "return" and "goto" are not so lucky. 141 142 For instance: 143 144 *INDENT-OFF* 145 146 volatile struct gdb_exception e; 147 TRY_CATCH (e, RETURN_MASK_ERROR) 148 { 149 } 150 switch (e.reason) 151 { 152 case RETURN_ERROR: ... 153 } 154 155 */ 156 157 #define TRY_CATCH(EXCEPTION,MASK) \ 158 { \ 159 EXCEPTIONS_SIGJMP_BUF *buf = \ 160 exceptions_state_mc_init (&(EXCEPTION), (MASK)); \ 161 EXCEPTIONS_SIGSETJMP (*buf); \ 162 } \ 163 while (exceptions_state_mc_action_iter ()) \ 164 while (exceptions_state_mc_action_iter_1 ()) 165 166 /* *INDENT-ON* */ 167 168 169 /* If E is an exception, print it's error message on the specified 170 stream. For _fprintf, prefix the message with PREFIX... */ 171 extern void exception_print (struct ui_file *file, struct gdb_exception e); 172 extern void exception_fprintf (struct ui_file *file, struct gdb_exception e, 173 const char *prefix, 174 ...) ATTRIBUTE_PRINTF (3, 4); 175 176 /* Throw an exception (as described by "struct gdb_exception"). Will 177 execute a LONG JUMP to the inner most containing exception handler 178 established using catch_exceptions() (or similar). 179 180 Code normally throws an exception using error() et.al. For various 181 reaons, GDB also contains code that throws an exception directly. 182 For instance, the remote*.c targets contain CNTRL-C signal handlers 183 that propogate the QUIT event up the exception chain. ``This could 184 be a good thing or a dangerous thing.'' -- the Existential 185 Wombat. */ 186 187 extern void throw_exception (struct gdb_exception exception) 188 ATTRIBUTE_NORETURN; 189 extern void throw_verror (enum errors, const char *fmt, va_list ap) 190 ATTRIBUTE_NORETURN ATTRIBUTE_PRINTF (2, 0); 191 extern void throw_vfatal (const char *fmt, va_list ap) 192 ATTRIBUTE_NORETURN ATTRIBUTE_PRINTF (1, 0); 193 extern void throw_error (enum errors error, const char *fmt, ...) 194 ATTRIBUTE_NORETURN ATTRIBUTE_PRINTF (2, 3); 195 196 /* Call FUNC(UIOUT, FUNC_ARGS) but wrapped within an exception 197 handler. If an exception (enum return_reason) is thrown using 198 throw_exception() than all cleanups installed since 199 catch_exceptions() was entered are invoked, the (-ve) exception 200 value is then returned by catch_exceptions. If FUNC() returns 201 normally (with a positive or zero return value) then that value is 202 returned by catch_exceptions(). It is an internal_error() for 203 FUNC() to return a negative value. 204 205 For the period of the FUNC() call: UIOUT is installed as the output 206 builder; ERRSTRING is installed as the error/quit message; and a 207 new cleanup_chain is established. The old values are restored 208 before catch_exceptions() returns. 209 210 The variant catch_exceptions_with_msg() is the same as 211 catch_exceptions() but adds the ability to return an allocated 212 copy of the gdb error message. This is used when a silent error is 213 issued and the caller wants to manually issue the error message. 214 215 MASK specifies what to catch; it is normally set to 216 RETURN_MASK_ALL, if for no other reason than that the code which 217 calls catch_errors might not be set up to deal with a quit which 218 isn't caught. But if the code can deal with it, it generally 219 should be RETURN_MASK_ERROR, unless for some reason it is more 220 useful to abort only the portion of the operation inside the 221 catch_errors. Note that quit should return to the command line 222 fairly quickly, even if some further processing is being done. 223 224 FIXME; cagney/2001-08-13: The need to override the global UIOUT 225 builder variable should just go away. 226 227 This function supersedes catch_errors(). 228 229 This function uses SETJMP() and LONGJUMP(). */ 230 231 struct ui_out; 232 typedef int (catch_exceptions_ftype) (struct ui_out *ui_out, void *args); 233 extern int catch_exceptions (struct ui_out *uiout, 234 catch_exceptions_ftype *func, void *func_args, 235 return_mask mask); 236 typedef void (catch_exception_ftype) (struct ui_out *ui_out, void *args); 237 extern int catch_exceptions_with_msg (struct ui_out *uiout, 238 catch_exceptions_ftype *func, 239 void *func_args, 240 char **gdberrmsg, 241 return_mask mask); 242 243 /* If CATCH_ERRORS_FTYPE throws an error, catch_errors() returns zero 244 otherwize the result from CATCH_ERRORS_FTYPE is returned. It is 245 probably useful for CATCH_ERRORS_FTYPE to always return a non-zero 246 value. It's unfortunate that, catch_errors() does not return an 247 indication of the exact exception that it caught - quit_flag might 248 help. 249 250 This function is superseded by catch_exceptions(). */ 251 252 typedef int (catch_errors_ftype) (void *); 253 extern int catch_errors (catch_errors_ftype *, void *, char *, return_mask); 254 255 /* Template to catch_errors() that wraps calls to command 256 functions. */ 257 258 typedef void (catch_command_errors_ftype) (char *, int); 259 extern int catch_command_errors (catch_command_errors_ftype *func, 260 char *arg, int from_tty, return_mask); 261 262 /* Like catch_command_errors, but works with const command and args. */ 263 264 typedef void (catch_command_errors_const_ftype) (const char *, int); 265 extern int catch_command_errors_const (catch_command_errors_const_ftype *func, 266 const char *arg, int from_tty, return_mask); 267 268 #endif 269