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_OPEN_FILE_FAILED,
 129         .desc      = "Could not open '%(filename)'",
 130     },
 131     {
 132         .error_fmt = QERR_PROPERTY_NOT_FOUND,
 133         .desc      = "Property '%(device).%(property)' not found",
 134     },
 135     {
 136         .error_fmt = QERR_PROPERTY_VALUE_BAD,
 137         .desc      = "Property '%(device).%(property)' doesn't take value '%(value)'",
 138     },
 139     {
 140         .error_fmt = QERR_PROPERTY_VALUE_IN_USE,
 141         .desc      = "Property '%(device).%(property)' can't take value '%(value)', it's in use",
 142     },
 143     {
 144         .error_fmt = QERR_PROPERTY_VALUE_NOT_FOUND,
 145         .desc      = "Property '%(device).%(property)' can't find value '%(value)'",
 146     },
 147     {
 148         .error_fmt = QERR_QMP_BAD_INPUT_OBJECT,
 149         .desc      = "Bad QMP input object",
 150     },
 151     {
 152         .error_fmt = QERR_SET_PASSWD_FAILED,
 153         .desc      = "Could not set password",
 154     },
 155     {
 156         .error_fmt = QERR_TOO_MANY_FILES,
 157         .desc      = "Too many open files",
 158     },
 159     {
 160         .error_fmt = QERR_UNDEFINED_ERROR,
 161         .desc      = "An undefined error has ocurred",
 162     },
 163     {
 164         .error_fmt = QERR_VNC_SERVER_FAILED,
 165         .desc      = "Could not start VNC server on %(target)",
 166     },
 167     {}
 168 };
 169
 170 /**
 171  * qerror_new(): Create a new QError
 172  *
 173  * Return strong reference.
 174  */
 175 QError *qerror_new(void)
 176 {
 177     QError *qerr;
 178
 179     qerr = qemu_mallocz(sizeof(*qerr));
 180     QOBJECT_INIT(qerr, &qerror_type);
 181
 182     return qerr;
 183 }
 184
 185 static void qerror_abort(const QError *qerr, const char *fmt, ...)
 186 {
 187     va_list ap;
 188
 189     fprintf(stderr, "qerror: bad call in function '%s':\n", qerr->func);
 190     fprintf(stderr, "qerror: -> ");
 191
 192     va_start(ap, fmt);
 193     vfprintf(stderr, fmt, ap);
 194     va_end(ap);
 195
 196     fprintf(stderr, "\nqerror: call at %s:%d\n", qerr->file, qerr->linenr);
 197     abort();
 198 }
 199
 200 static void qerror_set_data(QError *qerr, const char *fmt, va_list *va)
 201 {
 202     QObject *obj;
 203
 204     obj = qobject_from_jsonv(fmt, va);
 205     if (!obj) {
 206         qerror_abort(qerr, "invalid format '%s'", fmt);
 207     }
 208     if (qobject_type(obj) != QTYPE_QDICT) {
 209         qerror_abort(qerr, "error format is not a QDict '%s'", fmt);
 210     }
 211
 212     qerr->error = qobject_to_qdict(obj);
 213
 214     obj = qdict_get(qerr->error, "class");
 215     if (!obj) {
 216         qerror_abort(qerr, "missing 'class' key in '%s'", fmt);
 217     }
 218     if (qobject_type(obj) != QTYPE_QSTRING) {
 219         qerror_abort(qerr, "'class' key value should be a QString");
 220     }
 221
 222     obj = qdict_get(qerr->error, "data");
 223     if (!obj) {
 224         qerror_abort(qerr, "missing 'data' key in '%s'", fmt);
 225     }
 226     if (qobject_type(obj) != QTYPE_QDICT) {
 227         qerror_abort(qerr, "'data' key value should be a QDICT");
 228     }
 229 }
 230
 231 static void qerror_set_desc(QError *qerr, const char *fmt)
 232 {
 233     int i;
 234
 235     // FIXME: inefficient loop
 236
 237     for (i = 0; qerror_table[i].error_fmt; i++) {
 238         if (strcmp(qerror_table[i].error_fmt, fmt) == 0) {
 239             qerr->entry = &qerror_table[i];
 240             return;
 241         }
 242     }
 243
 244     qerror_abort(qerr, "error format '%s' not found", fmt);
 245 }
 246
 247 /**
 248  * qerror_from_info(): Create a new QError from error information
 249  *
 250  * The information consists of:
 251  *
 252  * - file   the file name of where the error occurred
 253  * - linenr the line number of where the error occurred
 254  * - func   the function name of where the error occurred
 255  * - fmt    JSON printf-like dictionary, there must exist keys 'class' and
 256  *          'data'
 257  * - va     va_list of all arguments specified by fmt
 258  *
 259  * Return strong reference.
 260  */
 261 QError *qerror_from_info(const char *file, int linenr, const char *func,
 262                          const char *fmt, va_list *va)
 263 {
 264     QError *qerr;
 265
 266     qerr = qerror_new();
 267     loc_save(&qerr->loc);
 268     qerr->linenr = linenr;
 269     qerr->file = file;
 270     qerr->func = func;
 271
 272     if (!fmt) {
 273         qerror_abort(qerr, "QDict not specified");
 274     }
 275
 276     qerror_set_data(qerr, fmt, va);
 277     qerror_set_desc(qerr, fmt);
 278
 279     return qerr;
 280 }
 281
 282 static void parse_error(const QError *qerror, int c)
 283 {
 284     qerror_abort(qerror, "expected '%c' in '%s'", c, qerror->entry->desc);
 285 }
 286
 287 static const char *append_field(QString *outstr, const QError *qerror,
 288                                 const char *start)
 289 {
 290     QObject *obj;
 291     QDict *qdict;
 292     QString *key_qs;
 293     const char *end, *key;
 294
 295     if (*start != '%')
 296         parse_error(qerror, '%');
 297     start++;
 298     if (*start != '(')
 299         parse_error(qerror, '(');
 300     start++;
 301
 302     end = strchr(start, ')');
 303     if (!end)
 304         parse_error(qerror, ')');
 305
 306     key_qs = qstring_from_substr(start, 0, end - start - 1);
 307     key = qstring_get_str(key_qs);
 308
 309     qdict = qobject_to_qdict(qdict_get(qerror->error, "data"));
 310     obj = qdict_get(qdict, key);
 311     if (!obj) {
 312         qerror_abort(qerror, "key '%s' not found in QDict", key);
 313     }
 314
 315     switch (qobject_type(obj)) {
 316         case QTYPE_QSTRING:
 317             qstring_append(outstr, qdict_get_str(qdict, key));
 318             break;
 319         case QTYPE_QINT:
 320             qstring_append_int(outstr, qdict_get_int(qdict, key));
 321             break;
 322         default:
 323             qerror_abort(qerror, "invalid type '%c'", qobject_type(obj));
 324     }
 325
 326     QDECREF(key_qs);
 327     return ++end;
 328 }
 329
 330 /**
 331  * qerror_human(): Format QError data into human-readable string.
 332  *
 333  * Formats according to member 'desc' of the specified QError object.
 334  */
 335 QString *qerror_human(const QError *qerror)
 336 {
 337     const char *p;
 338     QString *qstring;
 339
 340     assert(qerror->entry != NULL);
 341
 342     qstring = qstring_new();
 343
 344     for (p = qerror->entry->desc; *p != '\0';) {
 345         if (*p != '%') {
 346             qstring_append_chr(qstring, *p++);
 347         } else if (*(p + 1) == '%') {
 348             qstring_append_chr(qstring, '%');
 349             p += 2;
 350         } else {
 351             p = append_field(qstring, qerror, p);
 352         }
 353     }
 354
 355     return qstring;
 356 }
 357
 358 /**
 359  * qerror_print(): Print QError data
 360  *
 361  * This function will print the member 'desc' of the specified QError object,
 362  * it uses error_report() for this, so that the output is routed to the right
 363  * place (ie. stderr or Monitor's device).
 364  */
 365 void qerror_print(QError *qerror)
 366 {
 367     QString *qstring = qerror_human(qerror);
 368     loc_push_restore(&qerror->loc);
 369     error_report("%s", qstring_get_str(qstring));
 370     loc_pop(&qerror->loc);
 371     QDECREF(qstring);
 372 }
 373
 374 /**
 375  * qobject_to_qerror(): Convert a QObject into a QError
 376  */
 377 QError *qobject_to_qerror(const QObject *obj)
 378 {
 379     if (qobject_type(obj) != QTYPE_QERROR) {
 380         return NULL;
 381     }
 382
 383     return container_of(obj, QError, base);
 384 }
 385
 386 /**
 387  * qerror_destroy_obj(): Free all memory allocated by a QError
 388  */
 389 static void qerror_destroy_obj(QObject *obj)
 390 {
 391     QError *qerr;
 392
 393     assert(obj != NULL);
 394     qerr = qobject_to_qerror(obj);
 395
 396     QDECREF(qerr->error);
 397     qemu_free(qerr);
 398 }