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