1 /* -*- mode: C; c-file-style: "gnu"; indent-tabs-mode: nil; -*- */ 2 /* dbus-errors.c Error reporting 3 * 4 * Copyright (C) 2002, 2004 Red Hat Inc. 5 * Copyright (C) 2003 CodeFactory AB 6 * 7 * Licensed under the Academic Free License version 2.1 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 2 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, write to the Free Software 21 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA 22 * 23 */ 24 25 #include <config.h> 26 #include "dbus-errors.h" 27 #include "dbus-internals.h" 28 #include "dbus-string.h" 29 #include "dbus-protocol.h" 30 #include <stdarg.h> 31 #include <string.h> 32 33 /** 34 * @defgroup DBusErrorInternals Error reporting internals 35 * @ingroup DBusInternals 36 * @brief Error reporting internals 37 * @{ 38 */ 39 40 /** 41 * @def DBUS_ERROR_INIT 42 * 43 * Expands to a suitable initializer for a DBusError on the stack. 44 * Declaring a DBusError with: 45 * 46 * @code 47 * DBusError error = DBUS_ERROR_INIT; 48 * 49 * do_things_with (&error); 50 * @endcode 51 * 52 * is a more concise form of: 53 * 54 * @code 55 * DBusError error; 56 * 57 * dbus_error_init (&error); 58 * do_things_with (&error); 59 * @endcode 60 */ 61 62 /** 63 * Internals of DBusError 64 */ 65 typedef struct 66 { 67 char *name; /**< error name */ 68 char *message; /**< error message */ 69 70 unsigned int const_message : 1; /**< Message is not owned by DBusError */ 71 72 unsigned int dummy2 : 1; /**< placeholder */ 73 unsigned int dummy3 : 1; /**< placeholder */ 74 unsigned int dummy4 : 1; /**< placeholder */ 75 unsigned int dummy5 : 1; /**< placeholder */ 76 77 void *padding1; /**< placeholder */ 78 79 } DBusRealError; 80 81 /** 82 * Returns a longer message describing an error name. 83 * If the error name is unknown, returns the name 84 * itself. 85 * 86 * @param error the error to describe 87 * @returns a constant string describing the error. 88 */ 89 static const char* 90 message_from_error (const char *error) 91 { 92 if (strcmp (error, DBUS_ERROR_FAILED) == 0) 93 return "Unknown error"; 94 else if (strcmp (error, DBUS_ERROR_NO_MEMORY) == 0) 95 return "Not enough memory available"; 96 else if (strcmp (error, DBUS_ERROR_IO_ERROR) == 0) 97 return "Error reading or writing data"; 98 else if (strcmp (error, DBUS_ERROR_BAD_ADDRESS) == 0) 99 return "Could not parse address"; 100 else if (strcmp (error, DBUS_ERROR_NOT_SUPPORTED) == 0) 101 return "Feature not supported"; 102 else if (strcmp (error, DBUS_ERROR_LIMITS_EXCEEDED) == 0) 103 return "Resource limits exceeded"; 104 else if (strcmp (error, DBUS_ERROR_ACCESS_DENIED) == 0) 105 return "Permission denied"; 106 else if (strcmp (error, DBUS_ERROR_AUTH_FAILED) == 0) 107 return "Could not authenticate to server"; 108 else if (strcmp (error, DBUS_ERROR_NO_SERVER) == 0) 109 return "No server available at address"; 110 else if (strcmp (error, DBUS_ERROR_TIMEOUT) == 0) 111 return "Connection timed out"; 112 else if (strcmp (error, DBUS_ERROR_NO_NETWORK) == 0) 113 return "Network unavailable"; 114 else if (strcmp (error, DBUS_ERROR_ADDRESS_IN_USE) == 0) 115 return "Address already in use"; 116 else if (strcmp (error, DBUS_ERROR_DISCONNECTED) == 0) 117 return "Disconnected."; 118 else if (strcmp (error, DBUS_ERROR_INVALID_ARGS) == 0) 119 return "Invalid arguments."; 120 else if (strcmp (error, DBUS_ERROR_NO_REPLY) == 0) 121 return "Did not get a reply message."; 122 else if (strcmp (error, DBUS_ERROR_FILE_NOT_FOUND) == 0) 123 return "File doesn't exist."; 124 else if (strcmp (error, DBUS_ERROR_OBJECT_PATH_IN_USE) == 0) 125 return "Object path already in use"; 126 else 127 return error; 128 } 129 130 /** @} */ /* End of internals */ 131 132 /** 133 * @defgroup DBusErrors Error reporting 134 * @ingroup DBus 135 * @brief Error reporting 136 * 137 * Types and functions related to reporting errors. 138 * 139 * 140 * In essence D-Bus error reporting works as follows: 141 * 142 * @code 143 * DBusError error; 144 * dbus_error_init (&error); 145 * dbus_some_function (arg1, arg2, &error); 146 * if (dbus_error_is_set (&error)) 147 * { 148 * fprintf (stderr, "an error occurred: %s\n", error.message); 149 * dbus_error_free (&error); 150 * } 151 * @endcode 152 * 153 * By convention, all functions allow #NULL instead of a DBusError*, 154 * so callers who don't care about the error can ignore it. 155 * 156 * There are some rules. An error passed to a D-Bus function must 157 * always be unset; you can't pass in an error that's already set. If 158 * a function has a return code indicating whether an error occurred, 159 * and also a #DBusError parameter, then the error will always be set 160 * if and only if the return code indicates an error occurred. i.e. 161 * the return code and the error are never going to disagree. 162 * 163 * An error only needs to be freed if it's been set, not if 164 * it's merely been initialized. 165 * 166 * You can check the specific error that occurred using 167 * dbus_error_has_name(). 168 * 169 * Errors will not be set for programming errors, such as passing 170 * invalid arguments to the libdbus API. Instead, libdbus will print 171 * warnings, exit on a failed assertion, or even crash in those cases 172 * (in other words, incorrect use of the API results in undefined 173 * behavior, possibly accompanied by helpful debugging output if 174 * you're lucky). 175 * 176 * @{ 177 */ 178 179 /** 180 * Initializes a DBusError structure. Does not allocate any memory; 181 * the error only needs to be freed if it is set at some point. 182 * 183 * @param error the DBusError. 184 */ 185 void 186 dbus_error_init (DBusError *error) 187 { 188 DBusRealError *real; 189 190 _dbus_return_if_fail (error != NULL); 191 192 _dbus_assert (sizeof (DBusError) == sizeof (DBusRealError)); 193 194 real = (DBusRealError *)error; 195 196 real->name = NULL; 197 real->message = NULL; 198 199 real->const_message = TRUE; 200 } 201 202 /** 203 * Frees an error that's been set (or just initialized), 204 * then reinitializes the error as in dbus_error_init(). 205 * 206 * @param error memory where the error is stored. 207 */ 208 void 209 dbus_error_free (DBusError *error) 210 { 211 DBusRealError *real; 212 213 _dbus_return_if_fail (error != NULL); 214 215 real = (DBusRealError *)error; 216 217 if (!real->const_message) 218 { 219 dbus_free (real->name); 220 dbus_free (real->message); 221 } 222 223 dbus_error_init (error); 224 } 225 226 /** 227 * Assigns an error name and message to a DBusError. Does nothing if 228 * error is #NULL. The message may be #NULL, which means a default 229 * message will be deduced from the name. The default message will be 230 * totally useless, though, so using a #NULL message is not recommended. 231 * 232 * Because this function does not copy the error name or message, you 233 * must ensure the name and message are global data that won't be 234 * freed. You probably want dbus_set_error() instead, in most cases. 235 * 236 * @param error the error.or #NULL 237 * @param name the error name (not copied!!!) 238 * @param message the error message (not copied!!!) 239 */ 240 void 241 dbus_set_error_const (DBusError *error, 242 const char *name, 243 const char *message) 244 { 245 DBusRealError *real; 246 247 _dbus_return_if_error_is_set (error); 248 _dbus_return_if_fail (name != NULL); 249 250 if (error == NULL) 251 return; 252 253 _dbus_assert (error->name == NULL); 254 _dbus_assert (error->message == NULL); 255 256 if (message == NULL) 257 message = message_from_error (name); 258 259 real = (DBusRealError *)error; 260 261 real->name = (char*) name; 262 real->message = (char *)message; 263 real->const_message = TRUE; 264 } 265 266 /** 267 * Moves an error src into dest, freeing src and 268 * overwriting dest. Both src and dest must be initialized. 269 * src is reinitialized to an empty error. dest may not 270 * contain an existing error. If the destination is 271 * #NULL, just frees and reinits the source error. 272 * 273 * @param src the source error 274 * @param dest the destination error or #NULL 275 */ 276 void 277 dbus_move_error (DBusError *src, 278 DBusError *dest) 279 { 280 _dbus_return_if_error_is_set (dest); 281 282 if (dest) 283 { 284 dbus_error_free (dest); 285 *dest = *src; 286 dbus_error_init (src); 287 } 288 else 289 dbus_error_free (src); 290 } 291 292 /** 293 * Checks whether the error is set and has the given 294 * name. 295 * @param error the error 296 * @param name the name 297 * @returns #TRUE if the given named error occurred 298 */ 299 dbus_bool_t 300 dbus_error_has_name (const DBusError *error, 301 const char *name) 302 { 303 _dbus_return_val_if_fail (error != NULL, FALSE); 304 _dbus_return_val_if_fail (name != NULL, FALSE); 305 306 _dbus_assert ((error->name != NULL && error->message != NULL) || 307 (error->name == NULL && error->message == NULL)); 308 309 if (error->name != NULL) 310 { 311 DBusString str1, str2; 312 _dbus_string_init_const (&str1, error->name); 313 _dbus_string_init_const (&str2, name); 314 return _dbus_string_equal (&str1, &str2); 315 } 316 else 317 return FALSE; 318 } 319 320 /** 321 * Checks whether an error occurred (the error is set). 322 * 323 * @param error the error object 324 * @returns #TRUE if an error occurred 325 */ 326 dbus_bool_t 327 dbus_error_is_set (const DBusError *error) 328 { 329 _dbus_return_val_if_fail (error != NULL, FALSE); 330 _dbus_assert ((error->name != NULL && error->message != NULL) || 331 (error->name == NULL && error->message == NULL)); 332 return error->name != NULL; 333 } 334 335 /** 336 * Assigns an error name and message to a DBusError. 337 * Does nothing if error is #NULL. 338 * 339 * The format may be #NULL, which means a (pretty much useless) 340 * default message will be deduced from the name. This is not a good 341 * idea, just go ahead and provide a useful error message. It won't 342 * hurt you. 343 * 344 * If no memory can be allocated for the error message, 345 * an out-of-memory error message will be set instead. 346 * 347 * @param error the error.or #NULL 348 * @param name the error name 349 * @param format printf-style format string. 350 */ 351 void 352 dbus_set_error (DBusError *error, 353 const char *name, 354 const char *format, 355 ...) 356 { 357 DBusRealError *real; 358 DBusString str; 359 va_list args; 360 361 if (error == NULL) 362 return; 363 364 /* it's a bug to pile up errors */ 365 _dbus_return_if_error_is_set (error); 366 _dbus_return_if_fail (name != NULL); 367 368 _dbus_assert (error->name == NULL); 369 _dbus_assert (error->message == NULL); 370 371 if (!_dbus_string_init (&str)) 372 goto nomem; 373 374 if (format == NULL) 375 { 376 if (!_dbus_string_append (&str, 377 message_from_error (name))) 378 { 379 _dbus_string_free (&str); 380 va_end (args); 381 goto nomem; 382 } 383 } 384 else 385 { 386 va_start (args, format); 387 if (!_dbus_string_append_printf_valist (&str, format, args)) 388 { 389 _dbus_string_free (&str); 390 va_end (args); 391 goto nomem; 392 } 393 va_end (args); 394 } 395 396 real = (DBusRealError *)error; 397 398 if (!_dbus_string_steal_data (&str, &real->message)) 399 { 400 _dbus_string_free (&str); 401 goto nomem; 402 } 403 _dbus_string_free (&str); 404 405 real->name = _dbus_strdup (name); 406 if (real->name == NULL) 407 { 408 dbus_free (real->message); 409 real->message = NULL; 410 goto nomem; 411 } 412 real->const_message = FALSE; 413 414 return; 415 416 nomem: 417 _DBUS_SET_OOM (error); 418 } 419 420 /** @} */ /* End public API */ 421
