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 #include "qjson.h"
  13 #include "qerror.h"
  14 #include "qemu-common.h"
  15
  16 static void qerror_destroy_obj(QObject *obj);
  17
  18 static const QType qerror_type = {
  19     .code = QTYPE_QERROR,
  20     .destroy = qerror_destroy_obj,
  21 };
  22
  23 /**
  24  * The 'desc' parameter is a printf-like string, the format of the format
  25  * string is:
  26  *
  27  * %(KEY)
  28  *
  29  * Where KEY is a QDict key, which has to be passed to qerror_from_info().
  30  *
  31  * Example:
  32  *
  33  * "foo error on device: %(device) slot: %(slot_nr)"
  34  *
  35  * A single percent sign can be printed if followed by a second one,
  36  * for example:
  37  *
  38  * "running out of foo: %(foo)%%"
  39  */
  40 static const QErrorStringTable qerror_table[] = {
  41     {
  42         .error_fmt = QERR_BAD_BUS_FOR_DEVICE,
  43         .desc      = "Device '%(device)' can't go on a %(bad_bus_type) bus",
  44     },
  45     {
  46         .error_fmt = QERR_BUS_NOT_FOUND,
  47         .desc      = "Bus '%(bus)' not found",
  48     },
  49     {
  50         .error_fmt = QERR_BUS_NO_HOTPLUG,
  51         .desc      = "Bus '%(bus)' does not support hotplugging",
  52     },
  53     {
  54         .error_fmt = QERR_COMMAND_NOT_FOUND,
  55         .desc      = "The command %(name) has not been found",
  56     },
  57     {
  58         .error_fmt = QERR_DEVICE_ENCRYPTED,
  59         .desc      = "Device '%(device)' is encrypted",
  60     },
  61     {
  62         .error_fmt = QERR_DEVICE_INIT_FAILED,
  63         .desc      = "Device '%(device)' could not be initialized",
  64     },
  65     {
  66         .error_fmt = QERR_DEVICE_NOT_ENCRYPTED,
  67         .desc      = "Device '%(device)' is not encrypted",
  68     },
  69     {
  70         .error_fmt = QERR_DEVICE_LOCKED,
  71         .desc      = "Device '%(device)' is locked",
  72     },
  73     {
  74         .error_fmt = QERR_DEVICE_MULTIPLE_BUSSES,
  75         .desc      = "Device '%(device)' has multiple child busses",
  76     },
  77     {
  78         .error_fmt = QERR_DEVICE_NOT_ACTIVE,
  79         .desc      = "Device '%(device)' has not been activated by the guest",
  80     },
  81     {
  82         .error_fmt = QERR_DEVICE_NOT_FOUND,
  83         .desc      = "Device '%(device)' not found",
  84     },
  85     {
  86         .error_fmt = QERR_DEVICE_NOT_REMOVABLE,
  87         .desc      = "Device '%(device)' is not removable",
  88     },
  89     {
  90         .error_fmt = QERR_DEVICE_NO_BUS,
  91         .desc      = "Device '%(device)' has no child bus",
  92     },
  93     {
  94         .error_fmt = QERR_FD_NOT_FOUND,
  95         .desc      = "File descriptor named '%(name)' not found",
  96     },
  97     {
  98         .error_fmt = QERR_FD_NOT_SUPPLIED,
  99         .desc      = "No file descriptor supplied via SCM_RIGHTS",
 100     },
 101     {
 102         .error_fmt = QERR_INVALID_BLOCK_FORMAT,
 103         .desc      = "Invalid block format '%(name)'",
 104     },
 105     {
 106         .error_fmt = QERR_INVALID_PARAMETER,
 107         .desc      = "Invalid parameter '%(name)'",
 108     },
 109     {
 110         .error_fmt = QERR_INVALID_PARAMETER_TYPE,
 111         .desc      = "Invalid parameter type, expected: %(expected)",
 112     },
 113     {
 114         .error_fmt = QERR_INVALID_PASSWORD,
 115         .desc      = "Password incorrect",
 116     },
 117     {
 118         .error_fmt = QERR_JSON_PARSING,
 119         .desc      = "Invalid JSON syntax",
 120     },
 121     {
 122         .error_fmt = QERR_KVM_MISSING_CAP,
 123         .desc      = "Using KVM without %(capability), %(feature) unavailable",
 124     },
 125     {
 126         .error_fmt = QERR_MISSING_PARAMETER,
 127         .desc      = "Parameter '%(name)' is missing",
 128     },
 129     {
 130         .error_fmt = QERR_NO_BUS_FOR_DEVICE,
 131         .desc      = "No '%(bus)' bus found for device '%(device)'",
 132     },
 133     {
 134         .error_fmt = QERR_OPEN_FILE_FAILED,
 135         .desc      = "Could not open '%(filename)'",
 136     },
 137     {
 138         .error_fmt = QERR_PROPERTY_NOT_FOUND,
 139         .desc      = "Property '%(device).%(property)' not found",
 140     },
 141     {
 142         .error_fmt = QERR_PROPERTY_VALUE_BAD,
 143         .desc      = "Property '%(device).%(property)' doesn't take value '%(value)'",
 144     },
 145     {
 146         .error_fmt = QERR_PROPERTY_VALUE_IN_USE,
 147         .desc      = "Property '%(device).%(property)' can't take value '%(value)', it's in use",
 148     },
 149     {
 150         .error_fmt = QERR_PROPERTY_VALUE_NOT_FOUND,
 151         .desc      = "Property '%(device).%(property)' can't find value '%(value)'",
 152     },
 153     {
 154         .error_fmt = QERR_QMP_BAD_INPUT_OBJECT,
 155         .desc      = "Bad QMP input object",
 156     },
 157     {
 158         .error_fmt = QERR_SET_PASSWD_FAILED,
 159         .desc      = "Could not set password",
 160     },
 161     {
 162         .error_fmt = QERR_TOO_MANY_FILES,
 163         .desc      = "Too many open files",
 164     },
 165     {
 166         .error_fmt = QERR_UNDEFINED_ERROR,
 167         .desc      = "An undefined error has ocurred",
 168     },
 169     {
 170         .error_fmt = QERR_VNC_SERVER_FAILED,
 171         .desc      = "Could not start VNC server on %(target)",
 172     },
 173     {}
 174 };
 175
 176 /**
 177  * qerror_new(): Create a new QError
 178  *
 179  * Return strong reference.
 180  */
 181 QError *qerror_new(void)
 182 {
 183     QError *qerr;
 184
 185     qerr = qemu_mallocz(sizeof(*qerr));
 186     QOBJECT_INIT(qerr, &qerror_type);
 187
 188     return qerr;
 189 }
 190
 191 static void qerror_abort(const QError *qerr, const char *fmt, ...)
 192 {
 193     va_list ap;
 194
 195     fprintf(stderr, "qerror: bad call in function '%s':\n", qerr->func);
 196     fprintf(stderr, "qerror: -> ");
 197
 198     va_start(ap, fmt);
 199     vfprintf(stderr, fmt, ap);
 200     va_end(ap);
 201
 202     fprintf(stderr, "\nqerror: call at %s:%d\n", qerr->file, qerr->linenr);
 203     abort();
 204 }
 205
 206 static void qerror_set_data(QError *qerr, const char *fmt, va_list *va)
 207 {
 208     QObject *obj;
 209
 210     obj = qobject_from_jsonv(fmt, va);
 211     if (!obj) {
 212         qerror_abort(qerr, "invalid format '%s'", fmt);
 213     }
 214     if (qobject_type(obj) != QTYPE_QDICT) {
 215         qerror_abort(qerr, "error format is not a QDict '%s'", fmt);
 216     }
 217
 218     qerr->error = qobject_to_qdict(obj);
 219
 220     obj = qdict_get(qerr->error, "class");
 221     if (!obj) {
 222         qerror_abort(qerr, "missing 'class' key in '%s'", fmt);
 223     }
 224     if (qobject_type(obj) != QTYPE_QSTRING) {
 225         qerror_abort(qerr, "'class' key value should be a QString");
 226     }
 227
 228     obj = qdict_get(qerr->error, "data");
 229     if (!obj) {
 230         qerror_abort(qerr, "missing 'data' key in '%s'", fmt);
 231     }
 232     if (qobject_type(obj) != QTYPE_QDICT) {
 233         qerror_abort(qerr, "'data' key value should be a QDICT");
 234     }
 235 }
 236
 237 static void qerror_set_desc(QError *qerr, const char *fmt)
 238 {
 239     int i;
 240
 241     // FIXME: inefficient loop
 242
 243     for (i = 0; qerror_table[i].error_fmt; i++) {
 244         if (strcmp(qerror_table[i].error_fmt, fmt) == 0) {
 245             qerr->entry = &qerror_table[i];
 246             return;
 247         }
 248     }
 249
 250     qerror_abort(qerr, "error format '%s' not found", fmt);
 251 }
 252
 253 /**
 254  * qerror_from_info(): Create a new QError from error information
 255  *
 256  * The information consists of:
 257  *
 258  * - file   the file name of where the error occurred
 259  * - linenr the line number of where the error occurred
 260  * - func   the function name of where the error occurred
 261  * - fmt    JSON printf-like dictionary, there must exist keys 'class' and
 262  *          'data'
 263  * - va     va_list of all arguments specified by fmt
 264  *
 265  * Return strong reference.
 266  */
 267 QError *qerror_from_info(const char *file, int linenr, const char *func,
 268                          const char *fmt, va_list *va)
 269 {
 270     QError *qerr;
 271
 272     qerr = qerror_new();
 273     loc_save(&qerr->loc);
 274     qerr->linenr = linenr;
 275     qerr->file = file;
 276     qerr->func = func;
 277
 278     if (!fmt) {
 279         qerror_abort(qerr, "QDict not specified");
 280     }
 281
 282     qerror_set_data(qerr, fmt, va);
 283     qerror_set_desc(qerr, fmt);
 284
 285     return qerr;
 286 }
 287
 288 static void parse_error(const QError *qerror, int c)
 289 {
 290     qerror_abort(qerror, "expected '%c' in '%s'", c, qerror->entry->desc);
 291 }
 292
 293 static const char *append_field(QString *outstr, const QError *qerror,
 294                                 const char *start)
 295 {
 296     QObject *obj;
 297     QDict *qdict;
 298     QString *key_qs;
 299     const char *end, *key;
 300
 301     if (*start != '%')
 302         parse_error(qerror, '%');
 303     start++;
 304     if (*start != '(')
 305         parse_error(qerror, '(');
 306     start++;
 307
 308     end = strchr(start, ')');
 309     if (!end)
 310         parse_error(qerror, ')');
 311
 312     key_qs = qstring_from_substr(start, 0, end - start - 1);
 313     key = qstring_get_str(key_qs);
 314
 315     qdict = qobject_to_qdict(qdict_get(qerror->error, "data"));
 316     obj = qdict_get(qdict, key);
 317     if (!obj) {
 318         qerror_abort(qerror, "key '%s' not found in QDict", key);
 319     }
 320
 321     switch (qobject_type(obj)) {
 322         case QTYPE_QSTRING:
 323             qstring_append(outstr, qdict_get_str(qdict, key));
 324             break;
 325         case QTYPE_QINT:
 326             qstring_append_int(outstr, qdict_get_int(qdict, key));
 327             break;
 328         default:
 329             qerror_abort(qerror, "invalid type '%c'", qobject_type(obj));
 330     }
 331
 332     QDECREF(key_qs);
 333     return ++end;
 334 }
 335
 336 /**
 337  * qerror_human(): Format QError data into human-readable string.
 338  *
 339  * Formats according to member 'desc' of the specified QError object.
 340  */
 341 QString *qerror_human(const QError *qerror)
 342 {
 343     const char *p;
 344     QString *qstring;
 345
 346     assert(qerror->entry != NULL);
 347
 348     qstring = qstring_new();
 349
 350     for (p = qerror->entry->desc; *p != '\0';) {
 351         if (*p != '%') {
 352             qstring_append_chr(qstring, *p++);
 353         } else if (*(p + 1) == '%') {
 354             qstring_append_chr(qstring, '%');
 355             p += 2;
 356         } else {
 357             p = append_field(qstring, qerror, p);
 358         }
 359     }
 360
 361     return qstring;
 362 }
 363
 364 /**
 365  * qerror_print(): Print QError data
 366  *
 367  * This function will print the member 'desc' of the specified QError object,
 368  * it uses error_report() for this, so that the output is routed to the right
 369  * place (ie. stderr or Monitor's device).
 370  */
 371 void qerror_print(QError *qerror)
 372 {
 373     QString *qstring = qerror_human(qerror);
 374     loc_push_restore(&qerror->loc);
 375     error_report("%s", qstring_get_str(qstring));
 376     loc_pop(&qerror->loc);
 377     QDECREF(qstring);
 378 }
 379
 380 /**
 381  * qobject_to_qerror(): Convert a QObject into a QError
 382  */
 383 QError *qobject_to_qerror(const QObject *obj)
 384 {
 385     if (qobject_type(obj) != QTYPE_QERROR) {
 386         return NULL;
 387     }
 388
 389     return container_of(obj, QError, base);
 390 }
 391
 392 /**
 393  * qerror_destroy_obj(): Free all memory allocated by a QError
 394  */
 395 static void qerror_destroy_obj(QObject *obj)
 396 {
 397     QError *qerr;
 398
 399     assert(obj != NULL);
 400     qerr = qobject_to_qerror(obj);
 401
 402     QDECREF(qerr->error);
 403     qemu_free(qerr);
 404 }