| 1 | /* Exception (throw catch) mechanism, for GDB, the GNU debugger. |
| 2 | |
| 3 | Copyright (C) 1986-2015 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 | #include "defs.h" |
| 21 | #include "exceptions.h" |
| 22 | #include "breakpoint.h" |
| 23 | #include "target.h" |
| 24 | #include "inferior.h" |
| 25 | #include "annotate.h" |
| 26 | #include "ui-out.h" |
| 27 | #include "serial.h" |
| 28 | #include "gdbthread.h" |
| 29 | |
| 30 | void |
| 31 | prepare_to_throw_exception (void) |
| 32 | { |
| 33 | clear_quit_flag (); |
| 34 | immediate_quit = 0; |
| 35 | } |
| 36 | |
| 37 | static void |
| 38 | print_flush (void) |
| 39 | { |
| 40 | struct serial *gdb_stdout_serial; |
| 41 | |
| 42 | if (deprecated_error_begin_hook) |
| 43 | deprecated_error_begin_hook (); |
| 44 | |
| 45 | if (target_supports_terminal_ours ()) |
| 46 | target_terminal_ours (); |
| 47 | |
| 48 | /* We want all output to appear now, before we print the error. We |
| 49 | have 3 levels of buffering we have to flush (it's possible that |
| 50 | some of these should be changed to flush the lower-level ones |
| 51 | too): */ |
| 52 | |
| 53 | /* 1. The _filtered buffer. */ |
| 54 | if (filtered_printing_initialized ()) |
| 55 | wrap_here (""); |
| 56 | |
| 57 | /* 2. The stdio buffer. */ |
| 58 | gdb_flush (gdb_stdout); |
| 59 | gdb_flush (gdb_stderr); |
| 60 | |
| 61 | /* 3. The system-level buffer. */ |
| 62 | gdb_stdout_serial = serial_fdopen (1); |
| 63 | if (gdb_stdout_serial) |
| 64 | { |
| 65 | serial_drain_output (gdb_stdout_serial); |
| 66 | serial_un_fdopen (gdb_stdout_serial); |
| 67 | } |
| 68 | |
| 69 | annotate_error_begin (); |
| 70 | } |
| 71 | |
| 72 | static void |
| 73 | print_exception (struct ui_file *file, struct gdb_exception e) |
| 74 | { |
| 75 | /* KLUGE: cagney/2005-01-13: Write the string out one line at a time |
| 76 | as that way the MI's behavior is preserved. */ |
| 77 | const char *start; |
| 78 | const char *end; |
| 79 | |
| 80 | for (start = e.message; start != NULL; start = end) |
| 81 | { |
| 82 | end = strchr (start, '\n'); |
| 83 | if (end == NULL) |
| 84 | fputs_filtered (start, file); |
| 85 | else |
| 86 | { |
| 87 | end++; |
| 88 | ui_file_write (file, start, end - start); |
| 89 | } |
| 90 | } |
| 91 | fprintf_filtered (file, "\n"); |
| 92 | |
| 93 | /* Now append the annotation. */ |
| 94 | switch (e.reason) |
| 95 | { |
| 96 | case RETURN_QUIT: |
| 97 | annotate_quit (); |
| 98 | break; |
| 99 | case RETURN_ERROR: |
| 100 | /* Assume that these are all errors. */ |
| 101 | annotate_error (); |
| 102 | break; |
| 103 | default: |
| 104 | internal_error (__FILE__, __LINE__, _("Bad switch.")); |
| 105 | } |
| 106 | } |
| 107 | |
| 108 | void |
| 109 | exception_print (struct ui_file *file, struct gdb_exception e) |
| 110 | { |
| 111 | if (e.reason < 0 && e.message != NULL) |
| 112 | { |
| 113 | print_flush (); |
| 114 | print_exception (file, e); |
| 115 | } |
| 116 | } |
| 117 | |
| 118 | void |
| 119 | exception_fprintf (struct ui_file *file, struct gdb_exception e, |
| 120 | const char *prefix, ...) |
| 121 | { |
| 122 | if (e.reason < 0 && e.message != NULL) |
| 123 | { |
| 124 | va_list args; |
| 125 | |
| 126 | print_flush (); |
| 127 | |
| 128 | /* Print the prefix. */ |
| 129 | va_start (args, prefix); |
| 130 | vfprintf_filtered (file, prefix, args); |
| 131 | va_end (args); |
| 132 | |
| 133 | print_exception (file, e); |
| 134 | } |
| 135 | } |
| 136 | |
| 137 | /* Call FUNC(UIOUT, FUNC_ARGS) but wrapped within an exception |
| 138 | handler. If an exception (enum return_reason) is thrown using |
| 139 | throw_exception() than all cleanups installed since |
| 140 | catch_exceptions() was entered are invoked, the (-ve) exception |
| 141 | value is then returned by catch_exceptions. If FUNC() returns |
| 142 | normally (with a positive or zero return value) then that value is |
| 143 | returned by catch_exceptions(). It is an internal_error() for |
| 144 | FUNC() to return a negative value. |
| 145 | |
| 146 | See exceptions.h for further usage details. |
| 147 | |
| 148 | Must not be called with immediate_quit in effect (bad things might |
| 149 | happen, say we got a signal in the middle of a memcpy to quit_return). |
| 150 | This is an OK restriction; with very few exceptions immediate_quit can |
| 151 | be replaced by judicious use of QUIT. */ |
| 152 | |
| 153 | /* MAYBE: cagney/1999-11-05: catch_errors() in conjunction with |
| 154 | error() et al. could maintain a set of flags that indicate the |
| 155 | current state of each of the longjmp buffers. This would give the |
| 156 | longjmp code the chance to detect a longjmp botch (before it gets |
| 157 | to longjmperror()). Prior to 1999-11-05 this wasn't possible as |
| 158 | code also randomly used a SET_TOP_LEVEL macro that directly |
| 159 | initialized the longjmp buffers. */ |
| 160 | |
| 161 | int |
| 162 | catch_exceptions (struct ui_out *uiout, |
| 163 | catch_exceptions_ftype *func, |
| 164 | void *func_args, |
| 165 | return_mask mask) |
| 166 | { |
| 167 | return catch_exceptions_with_msg (uiout, func, func_args, NULL, mask); |
| 168 | } |
| 169 | |
| 170 | int |
| 171 | catch_exceptions_with_msg (struct ui_out *func_uiout, |
| 172 | catch_exceptions_ftype *func, |
| 173 | void *func_args, |
| 174 | char **gdberrmsg, |
| 175 | return_mask mask) |
| 176 | { |
| 177 | struct gdb_exception exception = exception_none; |
| 178 | volatile int val = 0; |
| 179 | struct ui_out *saved_uiout; |
| 180 | |
| 181 | /* Save and override the global ``struct ui_out'' builder. */ |
| 182 | saved_uiout = current_uiout; |
| 183 | current_uiout = func_uiout; |
| 184 | |
| 185 | TRY |
| 186 | { |
| 187 | val = (*func) (current_uiout, func_args); |
| 188 | } |
| 189 | CATCH (ex, RETURN_MASK_ALL) |
| 190 | { |
| 191 | exception = ex; |
| 192 | } |
| 193 | END_CATCH |
| 194 | |
| 195 | /* Restore the global builder. */ |
| 196 | current_uiout = saved_uiout; |
| 197 | |
| 198 | if (exception.reason < 0 && (mask & RETURN_MASK (exception.reason)) == 0) |
| 199 | { |
| 200 | /* The caller didn't request that the event be caught. |
| 201 | Rethrow. */ |
| 202 | throw_exception (exception); |
| 203 | } |
| 204 | |
| 205 | exception_print (gdb_stderr, exception); |
| 206 | gdb_assert (val >= 0); |
| 207 | gdb_assert (exception.reason <= 0); |
| 208 | if (exception.reason < 0) |
| 209 | { |
| 210 | /* If caller wants a copy of the low-level error message, make |
| 211 | one. This is used in the case of a silent error whereby the |
| 212 | caller may optionally want to issue the message. */ |
| 213 | if (gdberrmsg != NULL) |
| 214 | { |
| 215 | if (exception.message != NULL) |
| 216 | *gdberrmsg = xstrdup (exception.message); |
| 217 | else |
| 218 | *gdberrmsg = NULL; |
| 219 | } |
| 220 | return exception.reason; |
| 221 | } |
| 222 | return val; |
| 223 | } |
| 224 | |
| 225 | /* This function is superseded by catch_exceptions(). */ |
| 226 | |
| 227 | int |
| 228 | catch_errors (catch_errors_ftype *func, void *func_args, char *errstring, |
| 229 | return_mask mask) |
| 230 | { |
| 231 | struct gdb_exception exception = exception_none; |
| 232 | volatile int val = 0; |
| 233 | struct ui_out *saved_uiout; |
| 234 | |
| 235 | /* Save the global ``struct ui_out'' builder. */ |
| 236 | saved_uiout = current_uiout; |
| 237 | |
| 238 | TRY |
| 239 | { |
| 240 | val = func (func_args); |
| 241 | } |
| 242 | CATCH (ex, RETURN_MASK_ALL) |
| 243 | { |
| 244 | exception = ex; |
| 245 | } |
| 246 | END_CATCH |
| 247 | |
| 248 | /* Restore the global builder. */ |
| 249 | current_uiout = saved_uiout; |
| 250 | |
| 251 | if (exception.reason < 0 && (mask & RETURN_MASK (exception.reason)) == 0) |
| 252 | { |
| 253 | /* The caller didn't request that the event be caught. |
| 254 | Rethrow. */ |
| 255 | throw_exception (exception); |
| 256 | } |
| 257 | |
| 258 | exception_fprintf (gdb_stderr, exception, "%s", errstring); |
| 259 | if (exception.reason != 0) |
| 260 | return 0; |
| 261 | return val; |
| 262 | } |