| 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 | |
| 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 | /* Feature is not supported in this copy of GDB. */ |
| 83 | UNSUPPORTED_ERROR, |
| 84 | |
| 85 | /* Value not available. E.g., a register was not collected in a |
| 86 | traceframe. */ |
| 87 | NOT_AVAILABLE_ERROR, |
| 88 | |
| 89 | /* Value was optimized out. Note: if the value was a register, this |
| 90 | means the register was not saved in the frame. */ |
| 91 | OPTIMIZED_OUT_ERROR, |
| 92 | |
| 93 | /* DW_OP_GNU_entry_value resolving failed. */ |
| 94 | NO_ENTRY_VALUE_ERROR, |
| 95 | |
| 96 | /* Target throwing an error has been closed. Current command should be |
| 97 | aborted as the inferior state is no longer valid. */ |
| 98 | TARGET_CLOSE_ERROR, |
| 99 | |
| 100 | /* An undefined command was executed. */ |
| 101 | UNDEFINED_COMMAND_ERROR, |
| 102 | |
| 103 | /* Add more errors here. */ |
| 104 | NR_ERRORS |
| 105 | }; |
| 106 | |
| 107 | struct gdb_exception |
| 108 | { |
| 109 | enum return_reason reason; |
| 110 | enum errors error; |
| 111 | const char *message; |
| 112 | }; |
| 113 | |
| 114 | /* A pre-defined non-exception. */ |
| 115 | extern const struct gdb_exception exception_none; |
| 116 | |
| 117 | /* Wrap set/long jmp so that it's more portable (internal to |
| 118 | exceptions). */ |
| 119 | |
| 120 | #if defined(HAVE_SIGSETJMP) |
| 121 | #define EXCEPTIONS_SIGJMP_BUF sigjmp_buf |
| 122 | #define EXCEPTIONS_SIGSETJMP(buf) sigsetjmp((buf), 1) |
| 123 | #define EXCEPTIONS_SIGLONGJMP(buf,val) siglongjmp((buf), (val)) |
| 124 | #else |
| 125 | #define EXCEPTIONS_SIGJMP_BUF jmp_buf |
| 126 | #define EXCEPTIONS_SIGSETJMP(buf) setjmp(buf) |
| 127 | #define EXCEPTIONS_SIGLONGJMP(buf,val) longjmp((buf), (val)) |
| 128 | #endif |
| 129 | |
| 130 | /* Functions to drive the exceptions state m/c (internal to |
| 131 | exceptions). */ |
| 132 | EXCEPTIONS_SIGJMP_BUF *exceptions_state_mc_init (volatile struct |
| 133 | gdb_exception *exception, |
| 134 | return_mask mask); |
| 135 | int exceptions_state_mc_action_iter (void); |
| 136 | int exceptions_state_mc_action_iter_1 (void); |
| 137 | |
| 138 | /* Macro to wrap up standard try/catch behavior. |
| 139 | |
| 140 | The double loop lets us correctly handle code "break"ing out of the |
| 141 | try catch block. (It works as the "break" only exits the inner |
| 142 | "while" loop, the outer for loop detects this handling it |
| 143 | correctly.) Of course "return" and "goto" are not so lucky. |
| 144 | |
| 145 | For instance: |
| 146 | |
| 147 | *INDENT-OFF* |
| 148 | |
| 149 | volatile struct gdb_exception e; |
| 150 | TRY_CATCH (e, RETURN_MASK_ERROR) |
| 151 | { |
| 152 | } |
| 153 | switch (e.reason) |
| 154 | { |
| 155 | case RETURN_ERROR: ... |
| 156 | } |
| 157 | |
| 158 | */ |
| 159 | |
| 160 | #define TRY_CATCH(EXCEPTION,MASK) \ |
| 161 | { \ |
| 162 | EXCEPTIONS_SIGJMP_BUF *buf = \ |
| 163 | exceptions_state_mc_init (&(EXCEPTION), (MASK)); \ |
| 164 | EXCEPTIONS_SIGSETJMP (*buf); \ |
| 165 | } \ |
| 166 | while (exceptions_state_mc_action_iter ()) \ |
| 167 | while (exceptions_state_mc_action_iter_1 ()) |
| 168 | |
| 169 | /* *INDENT-ON* */ |
| 170 | |
| 171 | |
| 172 | /* If E is an exception, print it's error message on the specified |
| 173 | stream. For _fprintf, prefix the message with PREFIX... */ |
| 174 | extern void exception_print (struct ui_file *file, struct gdb_exception e); |
| 175 | extern void exception_fprintf (struct ui_file *file, struct gdb_exception e, |
| 176 | const char *prefix, |
| 177 | ...) ATTRIBUTE_PRINTF (3, 4); |
| 178 | |
| 179 | /* Throw an exception (as described by "struct gdb_exception"). Will |
| 180 | execute a LONG JUMP to the inner most containing exception handler |
| 181 | established using catch_exceptions() (or similar). |
| 182 | |
| 183 | Code normally throws an exception using error() et.al. For various |
| 184 | reaons, GDB also contains code that throws an exception directly. |
| 185 | For instance, the remote*.c targets contain CNTRL-C signal handlers |
| 186 | that propogate the QUIT event up the exception chain. ``This could |
| 187 | be a good thing or a dangerous thing.'' -- the Existential |
| 188 | Wombat. */ |
| 189 | |
| 190 | extern void throw_exception (struct gdb_exception exception) |
| 191 | ATTRIBUTE_NORETURN; |
| 192 | extern void throw_verror (enum errors, const char *fmt, va_list ap) |
| 193 | ATTRIBUTE_NORETURN ATTRIBUTE_PRINTF (2, 0); |
| 194 | extern void throw_vfatal (const char *fmt, va_list ap) |
| 195 | ATTRIBUTE_NORETURN ATTRIBUTE_PRINTF (1, 0); |
| 196 | extern void throw_error (enum errors error, const char *fmt, ...) |
| 197 | ATTRIBUTE_NORETURN ATTRIBUTE_PRINTF (2, 3); |
| 198 | |
| 199 | /* Call FUNC(UIOUT, FUNC_ARGS) but wrapped within an exception |
| 200 | handler. If an exception (enum return_reason) is thrown using |
| 201 | throw_exception() than all cleanups installed since |
| 202 | catch_exceptions() was entered are invoked, the (-ve) exception |
| 203 | value is then returned by catch_exceptions. If FUNC() returns |
| 204 | normally (with a positive or zero return value) then that value is |
| 205 | returned by catch_exceptions(). It is an internal_error() for |
| 206 | FUNC() to return a negative value. |
| 207 | |
| 208 | For the period of the FUNC() call: UIOUT is installed as the output |
| 209 | builder; ERRSTRING is installed as the error/quit message; and a |
| 210 | new cleanup_chain is established. The old values are restored |
| 211 | before catch_exceptions() returns. |
| 212 | |
| 213 | The variant catch_exceptions_with_msg() is the same as |
| 214 | catch_exceptions() but adds the ability to return an allocated |
| 215 | copy of the gdb error message. This is used when a silent error is |
| 216 | issued and the caller wants to manually issue the error message. |
| 217 | |
| 218 | MASK specifies what to catch; it is normally set to |
| 219 | RETURN_MASK_ALL, if for no other reason than that the code which |
| 220 | calls catch_errors might not be set up to deal with a quit which |
| 221 | isn't caught. But if the code can deal with it, it generally |
| 222 | should be RETURN_MASK_ERROR, unless for some reason it is more |
| 223 | useful to abort only the portion of the operation inside the |
| 224 | catch_errors. Note that quit should return to the command line |
| 225 | fairly quickly, even if some further processing is being done. |
| 226 | |
| 227 | FIXME; cagney/2001-08-13: The need to override the global UIOUT |
| 228 | builder variable should just go away. |
| 229 | |
| 230 | This function supersedes catch_errors(). |
| 231 | |
| 232 | This function uses SETJMP() and LONGJUMP(). */ |
| 233 | |
| 234 | struct ui_out; |
| 235 | typedef int (catch_exceptions_ftype) (struct ui_out *ui_out, void *args); |
| 236 | extern int catch_exceptions (struct ui_out *uiout, |
| 237 | catch_exceptions_ftype *func, void *func_args, |
| 238 | return_mask mask); |
| 239 | typedef void (catch_exception_ftype) (struct ui_out *ui_out, void *args); |
| 240 | extern int catch_exceptions_with_msg (struct ui_out *uiout, |
| 241 | catch_exceptions_ftype *func, |
| 242 | void *func_args, |
| 243 | char **gdberrmsg, |
| 244 | return_mask mask); |
| 245 | |
| 246 | /* If CATCH_ERRORS_FTYPE throws an error, catch_errors() returns zero |
| 247 | otherwize the result from CATCH_ERRORS_FTYPE is returned. It is |
| 248 | probably useful for CATCH_ERRORS_FTYPE to always return a non-zero |
| 249 | value. It's unfortunate that, catch_errors() does not return an |
| 250 | indication of the exact exception that it caught - quit_flag might |
| 251 | help. |
| 252 | |
| 253 | This function is superseded by catch_exceptions(). */ |
| 254 | |
| 255 | typedef int (catch_errors_ftype) (void *); |
| 256 | extern int catch_errors (catch_errors_ftype *, void *, char *, return_mask); |
| 257 | |
| 258 | /* Template to catch_errors() that wraps calls to command |
| 259 | functions. */ |
| 260 | |
| 261 | typedef void (catch_command_errors_ftype) (char *, int); |
| 262 | extern int catch_command_errors (catch_command_errors_ftype *func, |
| 263 | char *arg, int from_tty, return_mask); |
| 264 | |
| 265 | /* Like catch_command_errors, but works with const command and args. */ |
| 266 | |
| 267 | typedef void (catch_command_errors_const_ftype) (const char *, int); |
| 268 | extern int catch_command_errors_const (catch_command_errors_const_ftype *func, |
| 269 | const char *arg, int from_tty, return_mask); |
| 270 | |
| 271 | #endif |