qerror.c

   1 /*
   2  * QError: QEMU Error data-type.
   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_BUS_NOT_FOUND,
  53         .desc      = "Bus '%(bus)' not found",
  54     },
  55     {
  56         .error_fmt = QERR_BUS_NO_HOTPLUG,
  57         .desc      = "Bus '%(bus)' does not support hotplugging",
  58     },
  59     {
  60         .error_fmt = QERR_COMMAND_NOT_FOUND,
  61         .desc      = "The command %(name) has not been found",
  62     },
  63     {
  64         .error_fmt = QERR_DEVICE_ENCRYPTED,
  65         .desc      = "Device '%(device)' is encrypted",
  66     },
  67     {
  68         .error_fmt = QERR_DEVICE_INIT_FAILED,
  69         .desc      = "Device '%(device)' could not be initialized",
  70     },
  71     {
  72         .error_fmt = QERR_DEVICE_LOCKED,
  73         .desc      = "Device '%(device)' is locked",
  74     },
  75     {
  76         .error_fmt = QERR_DEVICE_MULTIPLE_BUSSES,
  77         .desc      = "Device '%(device)' has multiple child busses",
  78     },
  79     {
  80         .error_fmt = QERR_DEVICE_NOT_ACTIVE,
  81         .desc      = "Device '%(device)' has not been activated by the guest",
  82     },
  83     {
  84         .error_fmt = QERR_DEVICE_NOT_ENCRYPTED,
  85         .desc      = "Device '%(device)' is not encrypted",
  86     },
  87     {
  88         .error_fmt = QERR_DEVICE_NOT_FOUND,
  89         .desc      = "Device '%(device)' not found",
  90     },
  91     {
  92         .error_fmt = QERR_DEVICE_NOT_REMOVABLE,
  93         .desc      = "Device '%(device)' is not removable",
  94     },
  95     {
  96         .error_fmt = QERR_DEVICE_NO_BUS,
  97         .desc      = "Device '%(device)' has no child bus",
  98     },
  99     {
 100         .error_fmt = QERR_DUPLICATE_ID,
 101         .desc      = "Duplicate ID '%(id)' for %(object)",
 102     },
 103     {
 104         .error_fmt = QERR_FD_NOT_FOUND,
 105         .desc      = "File descriptor named '%(name)' not found",
 106     },
 107     {
 108         .error_fmt = QERR_FD_NOT_SUPPLIED,
 109         .desc      = "No file descriptor supplied via SCM_RIGHTS",
 110     },
 111     {
 112         .error_fmt = QERR_INVALID_BLOCK_FORMAT,
 113         .desc      = "Invalid block format '%(name)'",
 114     },
 115     {
 116         .error_fmt = QERR_INVALID_PARAMETER,
 117         .desc      = "Invalid parameter '%(name)'",
 118     },
 119     {
 120         .error_fmt = QERR_INVALID_PARAMETER_TYPE,
 121         .desc      = "Invalid parameter type, expected: %(expected)",
 122     },
 123     {
 124         .error_fmt = QERR_INVALID_PASSWORD,
 125         .desc      = "Password incorrect",
 126     },
 127     {
 128         .error_fmt = QERR_JSON_PARSING,
 129         .desc      = "Invalid JSON syntax",
 130     },
 131     {
 132         .error_fmt = QERR_KVM_MISSING_CAP,
 133         .desc      = "Using KVM without %(capability), %(feature) unavailable",
 134     },
 135     {
 136         .error_fmt = QERR_MISSING_PARAMETER,
 137         .desc      = "Parameter '%(name)' is missing",
 138     },
 139     {
 140         .error_fmt = QERR_NO_BUS_FOR_DEVICE,
 141         .desc      = "No '%(bus)' bus found for device '%(device)'",
 142     },
 143     {
 144         .error_fmt = QERR_OPEN_FILE_FAILED,
 145         .desc      = "Could not open '%(filename)'",
 146     },
 147     {
 148         .error_fmt = QERR_PROPERTY_NOT_FOUND,
 149         .desc      = "Property '%(device).%(property)' not found",
 150     },
 151     {
 152         .error_fmt = QERR_PROPERTY_VALUE_BAD,
 153         .desc      = "Property '%(device).%(property)' doesn't take value '%(value)'",
 154     },
 155     {
 156         .error_fmt = QERR_PROPERTY_VALUE_IN_USE,
 157         .desc      = "Property '%(device).%(property)' can't take value '%(value)', it's in use",
 158     },
 159     {
 160         .error_fmt = QERR_PROPERTY_VALUE_NOT_FOUND,
 161         .desc      = "Property '%(device).%(property)' can't find value '%(value)'",
 162     },
 163     {
 164         .error_fmt = QERR_QMP_BAD_INPUT_OBJECT,
 165         .desc      = "Bad QMP input object",
 166     },
 167     {
 168         .error_fmt = QERR_SET_PASSWD_FAILED,
 169         .desc      = "Could not set password",
 170     },
 171     {
 172         .error_fmt = QERR_TOO_MANY_FILES,
 173         .desc      = "Too many open files",
 174     },
 175     {
 176         .error_fmt = QERR_UNDEFINED_ERROR,
 177         .desc      = "An undefined error has ocurred",
 178     },
 179     {
 180         .error_fmt = QERR_VNC_SERVER_FAILED,
 181         .desc      = "Could not start VNC server on %(target)",
 182     },
 183     {}
 184 };
 185
 186 /**
 187  * qerror_new(): Create a new QError
 188  *
 189  * Return strong reference.
 190  */
 191 QError *qerror_new(void)
 192 {
 193     QError *qerr;
 194
 195     qerr = qemu_mallocz(sizeof(*qerr));
 196     QOBJECT_INIT(qerr, &qerror_type);
 197
 198     return qerr;
 199 }
 200
 201 static void qerror_abort(const QError *qerr, const char *fmt, ...)
 202 {
 203     va_list ap;
 204
 205     fprintf(stderr, "qerror: bad call in function '%s':\n", qerr->func);
 206     fprintf(stderr, "qerror: -> ");
 207
 208     va_start(ap, fmt);
 209     vfprintf(stderr, fmt, ap);
 210     va_end(ap);
 211
 212     fprintf(stderr, "\nqerror: call at %s:%d\n", qerr->file, qerr->linenr);
 213     abort();
 214 }
 215
 216 static void qerror_set_data(QError *qerr, const char *fmt, va_list *va)
 217 {
 218     QObject *obj;
 219
 220     obj = qobject_from_jsonv(fmt, va);
 221     if (!obj) {
 222         qerror_abort(qerr, "invalid format '%s'", fmt);
 223     }
 224     if (qobject_type(obj) != QTYPE_QDICT) {
 225         qerror_abort(qerr, "error format is not a QDict '%s'", fmt);
 226     }
 227
 228     qerr->error = qobject_to_qdict(obj);
 229
 230     obj = qdict_get(qerr->error, "class");
 231     if (!obj) {
 232         qerror_abort(qerr, "missing 'class' key in '%s'", fmt);
 233     }
 234     if (qobject_type(obj) != QTYPE_QSTRING) {
 235         qerror_abort(qerr, "'class' key value should be a QString");
 236     }
 237
 238     obj = qdict_get(qerr->error, "data");
 239     if (!obj) {
 240         qerror_abort(qerr, "missing 'data' key in '%s'", fmt);
 241     }
 242     if (qobject_type(obj) != QTYPE_QDICT) {
 243         qerror_abort(qerr, "'data' key value should be a QDICT");
 244     }
 245 }
 246
 247 static void qerror_set_desc(QError *qerr, const char *fmt)
 248 {
 249     int i;
 250
 251     // FIXME: inefficient loop
 252
 253     for (i = 0; qerror_table[i].error_fmt; i++) {
 254         if (strcmp(qerror_table[i].error_fmt, fmt) == 0) {
 255             qerr->entry = &qerror_table[i];
 256             return;
 257         }
 258     }
 259
 260     qerror_abort(qerr, "error format '%s' not found", fmt);
 261 }
 262
 263 /**
 264  * qerror_from_info(): Create a new QError from error information
 265  *
 266  * The information consists of:
 267  *
 268  * - file   the file name of where the error occurred
 269  * - linenr the line number of where the error occurred
 270  * - func   the function name of where the error occurred
 271  * - fmt    JSON printf-like dictionary, there must exist keys 'class' and
 272  *          'data'
 273  * - va     va_list of all arguments specified by fmt
 274  *
 275  * Return strong reference.
 276  */
 277 QError *qerror_from_info(const char *file, int linenr, const char *func,
 278                          const char *fmt, va_list *va)
 279 {
 280     QError *qerr;
 281
 282     qerr = qerror_new();
 283     loc_save(&qerr->loc);
 284     qerr->linenr = linenr;
 285     qerr->file = file;
 286     qerr->func = func;
 287
 288     if (!fmt) {
 289         qerror_abort(qerr, "QDict not specified");
 290     }
 291
 292     qerror_set_data(qerr, fmt, va);
 293     qerror_set_desc(qerr, fmt);
 294
 295     return qerr;
 296 }
 297
 298 static void parse_error(const QError *qerror, int c)
 299 {
 300     qerror_abort(qerror, "expected '%c' in '%s'", c, qerror->entry->desc);
 301 }
 302
 303 static const char *append_field(QString *outstr, const QError *qerror,
 304                                 const char *start)
 305 {
 306     QObject *obj;
 307     QDict *qdict;
 308     QString *key_qs;
 309     const char *end, *key;
 310
 311     if (*start != '%')
 312         parse_error(qerror, '%');
 313     start++;
 314     if (*start != '(')
 315         parse_error(qerror, '(');
 316     start++;
 317
 318     end = strchr(start, ')');
 319     if (!end)
 320         parse_error(qerror, ')');
 321
 322     key_qs = qstring_from_substr(start, 0, end - start - 1);
 323     key = qstring_get_str(key_qs);
 324
 325     qdict = qobject_to_qdict(qdict_get(qerror->error, "data"));
 326     obj = qdict_get(qdict, key);
 327     if (!obj) {
 328         qerror_abort(qerror, "key '%s' not found in QDict", key);
 329     }
 330
 331     switch (qobject_type(obj)) {
 332         case QTYPE_QSTRING:
 333             qstring_append(outstr, qdict_get_str(qdict, key));
 334             break;
 335         case QTYPE_QINT:
 336             qstring_append_int(outstr, qdict_get_int(qdict, key));
 337             break;
 338         default:
 339             qerror_abort(qerror, "invalid type '%c'", qobject_type(obj));
 340     }
 341
 342     QDECREF(key_qs);
 343     return ++end;
 344 }
 345
 346 /**
 347  * qerror_human(): Format QError data into human-readable string.
 348  *
 349  * Formats according to member 'desc' of the specified QError object.
 350  */
 351 QString *qerror_human(const QError *qerror)
 352 {
 353     const char *p;
 354     QString *qstring;
 355
 356     assert(qerror->entry != NULL);
 357
 358     qstring = qstring_new();
 359
 360     for (p = qerror->entry->desc; *p != '\0';) {
 361         if (*p != '%') {
 362             qstring_append_chr(qstring, *p++);
 363         } else if (*(p + 1) == '%') {
 364             qstring_append_chr(qstring, '%');
 365             p += 2;
 366         } else {
 367             p = append_field(qstring, qerror, p);
 368         }
 369     }
 370
 371     return qstring;
 372 }
 373
 374 /**
 375  * qerror_print(): Print QError data
 376  *
 377  * This function will print the member 'desc' of the specified QError object,
 378  * it uses error_report() for this, so that the output is routed to the right
 379  * place (ie. stderr or Monitor's device).
 380  */
 381 void qerror_print(QError *qerror)
 382 {
 383     QString *qstring = qerror_human(qerror);
 384     loc_push_restore(&qerror->loc);
 385     error_report("%s", qstring_get_str(qstring));
 386     loc_pop(&qerror->loc);
 387     QDECREF(qstring);
 388 }
 389
 390 void qerror_report_internal(const char *file, int linenr, const char *func,
 391                             const char *fmt, ...)
 392 {
 393     va_list va;
 394     QError *qerror;
 395
 396     va_start(va, fmt);
 397     qerror = qerror_from_info(file, linenr, func, fmt, &va);
 398     va_end(va);
 399
 400     if (monitor_cur_is_qmp()) {
 401         monitor_set_error(cur_mon, qerror);
 402     } else {
 403         qerror_print(qerror);
 404         QDECREF(qerror);
 405     }
 406 }
 407
 408 /**
 409  * qobject_to_qerror(): Convert a QObject into a QError
 410  */
 411 QError *qobject_to_qerror(const QObject *obj)
 412 {
 413     if (qobject_type(obj) != QTYPE_QERROR) {
 414         return NULL;
 415     }
 416
 417     return container_of(obj, QError, base);
 418 }
 419
 420 /**
 421  * qerror_destroy_obj(): Free all memory allocated by a QError
 422  */
 423 static void qerror_destroy_obj(QObject *obj)
 424 {
 425     QError *qerr;
 426
 427     assert(obj != NULL);
 428     qerr = qobject_to_qerror(obj);
 429
 430     QDECREF(qerr->error);
 431     qemu_free(qerr);
 432 }