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