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