qerror.c

   1 /*
   2  * QError Module
   3  *
   4  * Copyright (C) 2009 Red Hat Inc.
   5  *
   6  * Authors:
   7  *  Luiz Capitulino <lcapitulino@redhat.com>
   8  *
   9  * This work is licensed under the terms of the GNU LGPL, version 2.1 or later.
  10  * See the COPYING.LIB file in the top-level directory.
  11  */
  12
  13 #include "monitor.h"
  14 #include "qjson.h"
  15 #include "qerror.h"
  16 #include "qemu-common.h"
  17
  18 static void qerror_destroy_obj(QObject *obj);
  19
  20 static const QType qerror_type = {
  21     .code = QTYPE_QERROR,
  22     .destroy = qerror_destroy_obj,
  23 };
  24
  25 /**
  26  * The 'desc' parameter is a printf-like string, the format of the format
  27  * string is:
  28  *
  29  * %(KEY)
  30  *
  31  * Where KEY is a QDict key, which has to be passed to qerror_from_info().
  32  *
  33  * Example:
  34  *
  35  * "foo error on device: %(device) slot: %(slot_nr)"
  36  *
  37  * A single percent sign can be printed if followed by a second one,
  38  * for example:
  39  *
  40  * "running out of foo: %(foo)%%"
  41  *
  42  * Please keep the entries in alphabetical order.
  43  * Use "sed -n '/^static.*qerror_table\[\]/,/^};/s/QERR_/&/gp' qerror.c | sort -c"
  44  * to check.
  45  */
  46 static const QErrorStringTable qerror_table[] = {
  47     {
  48         .error_fmt = QERR_BAD_BUS_FOR_DEVICE,
  49         .desc      = "Device '%(device)' can't go on a %(bad_bus_type) bus",
  50     },
  51     {
  52         .error_fmt = QERR_BLOCK_FORMAT_FEATURE_NOT_SUPPORTED,
  53         .desc      = "Block format '%(format)' used by device '%(name)' does not support feature '%(feature)'",
  54     },
  55     {
  56         .error_fmt = QERR_BUS_NOT_FOUND,
  57         .desc      = "Bus '%(bus)' not found",
  58     },
  59     {
  60         .error_fmt = QERR_BUS_NO_HOTPLUG,
  61         .desc      = "Bus '%(bus)' does not support hotplugging",
  62     },
  63     {
  64         .error_fmt = QERR_COMMAND_NOT_FOUND,
  65         .desc      = "The command %(name) has not been found",
  66     },
  67     {
  68         .error_fmt = QERR_COMMAND_DISABLED,
  69         .desc      = "The command %(name) has been disabled for this instance",
  70     },
  71     {
  72         .error_fmt = QERR_DEVICE_ENCRYPTED,
  73         .desc      = "Device '%(device)' is encrypted",
  74     },
  75     {
  76         .error_fmt = QERR_DEVICE_INIT_FAILED,
  77         .desc      = "Device '%(device)' could not be initialized",
  78     },
  79     {
  80         .error_fmt = QERR_DEVICE_IN_USE,
  81         .desc      = "Device '%(device)' is in use",
  82     },
  83     {
  84         .error_fmt = QERR_DEVICE_FEATURE_BLOCKS_MIGRATION,
  85         .desc      = "Migration is disabled when using feature '%(feature)' in device '%(device)'",
  86     },
  87     {
  88         .error_fmt = QERR_DEVICE_LOCKED,
  89         .desc      = "Device '%(device)' is locked",
  90     },
  91     {
  92         .error_fmt = QERR_DEVICE_MULTIPLE_BUSSES,
  93         .desc      = "Device '%(device)' has multiple child busses",
  94     },
  95     {
  96         .error_fmt = QERR_DEVICE_NOT_ACTIVE,
  97         .desc      = "Device '%(device)' has not been activated",
  98     },
  99     {
 100         .error_fmt = QERR_DEVICE_NOT_ENCRYPTED,
 101         .desc      = "Device '%(device)' is not encrypted",
 102     },
 103     {
 104         .error_fmt = QERR_DEVICE_NOT_FOUND,
 105         .desc      = "Device '%(device)' not found",
 106     },
 107     {
 108         .error_fmt = QERR_DEVICE_NOT_REMOVABLE,
 109         .desc      = "Device '%(device)' is not removable",
 110     },
 111     {
 112         .error_fmt = QERR_DEVICE_NO_BUS,
 113         .desc      = "Device '%(device)' has no child bus",
 114     },
 115     {
 116         .error_fmt = QERR_DEVICE_NO_HOTPLUG,
 117         .desc      = "Device '%(device)' does not support hotplugging",
 118     },
 119     {
 120         .error_fmt = QERR_DUPLICATE_ID,
 121         .desc      = "Duplicate ID '%(id)' for %(object)",
 122     },
 123     {
 124         .error_fmt = QERR_FD_NOT_FOUND,
 125         .desc      = "File descriptor named '%(name)' not found",
 126     },
 127     {
 128         .error_fmt = QERR_FD_NOT_SUPPLIED,
 129         .desc      = "No file descriptor supplied via SCM_RIGHTS",
 130     },
 131     {
 132         .error_fmt = QERR_FEATURE_DISABLED,
 133         .desc      = "The feature '%(name)' is not enabled",
 134     },
 135     {
 136         .error_fmt = QERR_INVALID_BLOCK_FORMAT,
 137         .desc      = "Invalid block format '%(name)'",
 138     },
 139     {
 140         .error_fmt = QERR_INVALID_PARAMETER,
 141         .desc      = "Invalid parameter '%(name)'",
 142     },
 143     {
 144         .error_fmt = QERR_INVALID_PARAMETER_TYPE,
 145         .desc      = "Invalid parameter type, expected: %(expected)",
 146     },
 147     {
 148         .error_fmt = QERR_INVALID_PARAMETER_VALUE,
 149         .desc      = "Parameter '%(name)' expects %(expected)",
 150     },
 151     {
 152         .error_fmt = QERR_INVALID_PASSWORD,
 153         .desc      = "Password incorrect",
 154     },
 155     {
 156         .error_fmt = QERR_IO_ERROR,
 157         .desc      = "An IO error has occurred",
 158     },
 159     {
 160         .error_fmt = QERR_JSON_PARSING,
 161         .desc      = "Invalid JSON syntax",
 162     },
 163     {
 164         .error_fmt = QERR_JSON_PARSE_ERROR,
 165         .desc      = "JSON parse error, %(message)",
 166
 167     },
 168     {
 169         .error_fmt = QERR_KVM_MISSING_CAP,
 170         .desc      = "Using KVM without %(capability), %(feature) unavailable",
 171     },
 172     {
 173         .error_fmt = QERR_MIGRATION_EXPECTED,
 174         .desc      = "An incoming migration is expected before this command can be executed",
 175     },
 176     {
 177         .error_fmt = QERR_MISSING_PARAMETER,
 178         .desc      = "Parameter '%(name)' is missing",
 179     },
 180     {
 181         .error_fmt = QERR_NO_BUS_FOR_DEVICE,
 182         .desc      = "No '%(bus)' bus found for device '%(device)'",
 183     },
 184     {
 185         .error_fmt = QERR_OPEN_FILE_FAILED,
 186         .desc      = "Could not open '%(filename)'",
 187     },
 188     {
 189         .error_fmt = QERR_PROPERTY_NOT_FOUND,
 190         .desc      = "Property '%(device).%(property)' not found",
 191     },
 192     {
 193         .error_fmt = QERR_PROPERTY_VALUE_BAD,
 194         .desc      = "Property '%(device).%(property)' doesn't take value '%(value)'",
 195     },
 196     {
 197         .error_fmt = QERR_PROPERTY_VALUE_IN_USE,
 198         .desc      = "Property '%(device).%(property)' can't take value '%(value)', it's in use",
 199     },
 200     {
 201         .error_fmt = QERR_PROPERTY_VALUE_NOT_FOUND,
 202         .desc      = "Property '%(device).%(property)' can't find value '%(value)'",
 203     },
 204     {
 205         .error_fmt = QERR_QMP_BAD_INPUT_OBJECT,
 206         .desc      = "Expected '%(expected)' in QMP input",
 207     },
 208     {
 209         .error_fmt = QERR_QMP_BAD_INPUT_OBJECT_MEMBER,
 210         .desc      = "QMP input object member '%(member)' expects '%(expected)'",
 211     },
 212     {
 213         .error_fmt = QERR_QMP_EXTRA_MEMBER,
 214         .desc      = "QMP input object member '%(member)' is unexpected",
 215     },
 216     {
 217         .error_fmt = QERR_RESET_REQUIRED,
 218         .desc      = "Resetting the Virtual Machine is required",
 219     },
 220     {
 221         .error_fmt = QERR_SET_PASSWD_FAILED,
 222         .desc      = "Could not set password",
 223     },
 224     {
 225         .error_fmt = QERR_ADD_CLIENT_FAILED,
 226         .desc      = "Could not add client",
 227     },
 228     {
 229         .error_fmt = QERR_TOO_MANY_FILES,
 230         .desc      = "Too many open files",
 231     },
 232     {
 233         .error_fmt = QERR_UNDEFINED_ERROR,
 234         .desc      = "An undefined error has occurred",
 235     },
 236     {
 237         .error_fmt = QERR_UNSUPPORTED,
 238         .desc      = "this feature or command is not currently supported",
 239     },
 240     {
 241         .error_fmt = QERR_UNKNOWN_BLOCK_FORMAT_FEATURE,
 242         .desc      = "'%(device)' uses a %(format) feature which is not "
 243                      "supported by this qemu version: %(feature)",
 244     },
 245     {
 246         .error_fmt = QERR_VIRTFS_FEATURE_BLOCKS_MIGRATION,
 247         .desc      = "Migration is disabled when VirtFS export path '%(path)' "
 248                      "is mounted in the guest using mount_tag '%(tag)'",
 249     },
 250     {
 251         .error_fmt = QERR_VNC_SERVER_FAILED,
 252         .desc      = "Could not start VNC server on %(target)",
 253     },
 254     {
 255         .error_fmt = QERR_QGA_LOGGING_FAILED,
 256         .desc      = "Guest agent failed to log non-optional log statement",
 257     },
 258     {
 259         .error_fmt = QERR_QGA_COMMAND_FAILED,
 260         .desc      = "Guest agent command failed, error was '%(message)'",
 261     },
 262     {
 263         .error_fmt = QERR_INVALID_PARAMETER_COMBINATION,
 264         .desc      = "Invalid parameter combination",
 265     },
 266     {}
 267 };
 268
 269 /**
 270  * qerror_new(): Create a new QError
 271  *
 272  * Return strong reference.
 273  */
 274 QError *qerror_new(void)
 275 {
 276     QError *qerr;
 277
 278     qerr = g_malloc0(sizeof(*qerr));
 279     QOBJECT_INIT(qerr, &qerror_type);
 280
 281     return qerr;
 282 }
 283
 284 static void GCC_FMT_ATTR(2, 3) qerror_abort(const QError *qerr,
 285                                             const char *fmt, ...)
 286 {
 287     va_list ap;
 288
 289     fprintf(stderr, "qerror: bad call in function '%s':\n", qerr->func);
 290     fprintf(stderr, "qerror: -> ");
 291
 292     va_start(ap, fmt);
 293     vfprintf(stderr, fmt, ap);
 294     va_end(ap);
 295
 296     fprintf(stderr, "\nqerror: call at %s:%d\n", qerr->file, qerr->linenr);
 297     abort();
 298 }
 299
 300 static void GCC_FMT_ATTR(2, 0) qerror_set_data(QError *qerr,
 301                                                const char *fmt, va_list *va)
 302 {
 303     QObject *obj;
 304
 305     obj = qobject_from_jsonv(fmt, va);
 306     if (!obj) {
 307         qerror_abort(qerr, "invalid format '%s'", fmt);
 308     }
 309     if (qobject_type(obj) != QTYPE_QDICT) {
 310         qerror_abort(qerr, "error format is not a QDict '%s'", fmt);
 311     }
 312
 313     qerr->error = qobject_to_qdict(obj);
 314
 315     obj = qdict_get(qerr->error, "class");
 316     if (!obj) {
 317         qerror_abort(qerr, "missing 'class' key in '%s'", fmt);
 318     }
 319     if (qobject_type(obj) != QTYPE_QSTRING) {
 320         qerror_abort(qerr, "'class' key value should be a QString");
 321     }
 322
 323     obj = qdict_get(qerr->error, "data");
 324     if (!obj) {
 325         qerror_abort(qerr, "missing 'data' key in '%s'", fmt);
 326     }
 327     if (qobject_type(obj) != QTYPE_QDICT) {
 328         qerror_abort(qerr, "'data' key value should be a QDICT");
 329     }
 330 }
 331
 332 static void qerror_set_desc(QError *qerr, const char *fmt)
 333 {
 334     int i;
 335
 336     // FIXME: inefficient loop
 337
 338     for (i = 0; qerror_table[i].error_fmt; i++) {
 339         if (strcmp(qerror_table[i].error_fmt, fmt) == 0) {
 340             qerr->entry = &qerror_table[i];
 341             return;
 342         }
 343     }
 344
 345     qerror_abort(qerr, "error format '%s' not found", fmt);
 346 }
 347
 348 /**
 349  * qerror_from_info(): Create a new QError from error information
 350  *
 351  * The information consists of:
 352  *
 353  * - file   the file name of where the error occurred
 354  * - linenr the line number of where the error occurred
 355  * - func   the function name of where the error occurred
 356  * - fmt    JSON printf-like dictionary, there must exist keys 'class' and
 357  *          'data'
 358  * - va     va_list of all arguments specified by fmt
 359  *
 360  * Return strong reference.
 361  */
 362 QError *qerror_from_info(const char *file, int linenr, const char *func,
 363                          const char *fmt, va_list *va)
 364 {
 365     QError *qerr;
 366
 367     qerr = qerror_new();
 368     loc_save(&qerr->loc);
 369     qerr->linenr = linenr;
 370     qerr->file = file;
 371     qerr->func = func;
 372
 373     if (!fmt) {
 374         qerror_abort(qerr, "QDict not specified");
 375     }
 376
 377     qerror_set_data(qerr, fmt, va);
 378     qerror_set_desc(qerr, fmt);
 379
 380     return qerr;
 381 }
 382
 383 static void parse_error(const QErrorStringTable *entry, int c)
 384 {
 385     fprintf(stderr, "expected '%c' in '%s'", c, entry->desc);
 386     abort();
 387 }
 388
 389 static const char *append_field(QDict *error, QString *outstr,
 390                                 const QErrorStringTable *entry,
 391                                 const char *start)
 392 {
 393     QObject *obj;
 394     QDict *qdict;
 395     QString *key_qs;
 396     const char *end, *key;
 397
 398     if (*start != '%')
 399         parse_error(entry, '%');
 400     start++;
 401     if (*start != '(')
 402         parse_error(entry, '(');
 403     start++;
 404
 405     end = strchr(start, ')');
 406     if (!end)
 407         parse_error(entry, ')');
 408
 409     key_qs = qstring_from_substr(start, 0, end - start - 1);
 410     key = qstring_get_str(key_qs);
 411
 412     qdict = qobject_to_qdict(qdict_get(error, "data"));
 413     obj = qdict_get(qdict, key);
 414     if (!obj) {
 415         abort();
 416     }
 417
 418     switch (qobject_type(obj)) {
 419         case QTYPE_QSTRING:
 420             qstring_append(outstr, qdict_get_str(qdict, key));
 421             break;
 422         case QTYPE_QINT:
 423             qstring_append_int(outstr, qdict_get_int(qdict, key));
 424             break;
 425         default:
 426             abort();
 427     }
 428
 429     QDECREF(key_qs);
 430     return ++end;
 431 }
 432
 433 static QString *qerror_format_desc(QDict *error,
 434                                    const QErrorStringTable *entry)
 435 {
 436     QString *qstring;
 437     const char *p;
 438
 439     assert(entry != NULL);
 440
 441     qstring = qstring_new();
 442
 443     for (p = entry->desc; *p != '\0';) {
 444         if (*p != '%') {
 445             qstring_append_chr(qstring, *p++);
 446         } else if (*(p + 1) == '%') {
 447             qstring_append_chr(qstring, '%');
 448             p += 2;
 449         } else {
 450             p = append_field(error, qstring, entry, p);
 451         }
 452     }
 453
 454     return qstring;
 455 }
 456
 457 QString *qerror_format(const char *fmt, QDict *error)
 458 {
 459     const QErrorStringTable *entry = NULL;
 460     int i;
 461
 462     for (i = 0; qerror_table[i].error_fmt; i++) {
 463         if (strcmp(qerror_table[i].error_fmt, fmt) == 0) {
 464             entry = &qerror_table[i];
 465             break;
 466         }
 467     }
 468
 469     return qerror_format_desc(error, entry);
 470 }
 471
 472 /**
 473  * qerror_human(): Format QError data into human-readable string.
 474  */
 475 QString *qerror_human(const QError *qerror)
 476 {
 477     return qerror_format_desc(qerror->error, qerror->entry);
 478 }
 479
 480 /**
 481  * qerror_print(): Print QError data
 482  *
 483  * This function will print the member 'desc' of the specified QError object,
 484  * it uses error_report() for this, so that the output is routed to the right
 485  * place (ie. stderr or Monitor's device).
 486  */
 487 void qerror_print(QError *qerror)
 488 {
 489     QString *qstring = qerror_human(qerror);
 490     loc_push_restore(&qerror->loc);
 491     error_report("%s", qstring_get_str(qstring));
 492     loc_pop(&qerror->loc);
 493     QDECREF(qstring);
 494 }
 495
 496 void qerror_report_internal(const char *file, int linenr, const char *func,
 497                             const char *fmt, ...)
 498 {
 499     va_list va;
 500     QError *qerror;
 501
 502     va_start(va, fmt);
 503     qerror = qerror_from_info(file, linenr, func, fmt, &va);
 504     va_end(va);
 505
 506     if (monitor_cur_is_qmp()) {
 507         monitor_set_error(cur_mon, qerror);
 508     } else {
 509         qerror_print(qerror);
 510         QDECREF(qerror);
 511     }
 512 }
 513
 514 /* Evil... */
 515 struct Error
 516 {
 517     QDict *obj;
 518     const char *fmt;
 519     char *msg;
 520 };
 521
 522 void qerror_report_err(Error *err)
 523 {
 524     QError *qerr;
 525     int i;
 526
 527     qerr = qerror_new();
 528     loc_save(&qerr->loc);
 529     QINCREF(err->obj);
 530     qerr->error = err->obj;
 531
 532     for (i = 0; qerror_table[i].error_fmt; i++) {
 533         if (strcmp(qerror_table[i].error_fmt, err->fmt) == 0) {
 534             qerr->entry = &qerror_table[i];
 535             break;
 536         }
 537     }
 538
 539     if (monitor_cur_is_qmp()) {
 540         monitor_set_error(cur_mon, qerr);
 541     } else {
 542         qerror_print(qerr);
 543         QDECREF(qerr);
 544     }
 545 }
 546
 547 /**
 548  * qobject_to_qerror(): Convert a QObject into a QError
 549  */
 550 QError *qobject_to_qerror(const QObject *obj)
 551 {
 552     if (qobject_type(obj) != QTYPE_QERROR) {
 553         return NULL;
 554     }
 555
 556     return container_of(obj, QError, base);
 557 }
 558
 559 /**
 560  * qerror_destroy_obj(): Free all memory allocated by a QError
 561  */
 562 static void qerror_destroy_obj(QObject *obj)
 563 {
 564     QError *qerr;
 565
 566     assert(obj != NULL);
 567     qerr = qobject_to_qerror(obj);
 568
 569     QDECREF(qerr->error);
 570     g_free(qerr);
 571 }