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_PROPERTY_VALUE_IN_USE,
 117         .desc      = "Property '%(device).%(property)' can't take value '%(value)', it's in use",
 118     },
 119     {
 120         .error_fmt = QERR_PROPERTY_VALUE_NOT_FOUND,
 121         .desc      = "Property '%(device).%(property)' can't find value '%(value)'",
 122     },
 123     {
 124         .error_fmt = QERR_QMP_BAD_INPUT_OBJECT,
 125         .desc      = "Bad QMP input object",
 126     },
 127     {
 128         .error_fmt = QERR_SET_PASSWD_FAILED,
 129         .desc      = "Could not set password",
 130     },
 131     {
 132         .error_fmt = QERR_TOO_MANY_FILES,
 133         .desc      = "Too many open files",
 134     },
 135     {
 136         .error_fmt = QERR_UNDEFINED_ERROR,
 137         .desc      = "An undefined error has ocurred",
 138     },
 139     {
 140         .error_fmt = QERR_VNC_SERVER_FAILED,
 141         .desc      = "Could not start VNC server on %(target)",
 142     },
 143     {}
 144 };
 145
 146 /**
 147  * qerror_new(): Create a new QError
 148  *
 149  * Return strong reference.
 150  */
 151 QError *qerror_new(void)
 152 {
 153     QError *qerr;
 154
 155     qerr = qemu_mallocz(sizeof(*qerr));
 156     QOBJECT_INIT(qerr, &qerror_type);
 157
 158     return qerr;
 159 }
 160
 161 static void qerror_abort(const QError *qerr, const char *fmt, ...)
 162 {
 163     va_list ap;
 164
 165     fprintf(stderr, "qerror: bad call in function '%s':\n", qerr->func);
 166     fprintf(stderr, "qerror: -> ");
 167
 168     va_start(ap, fmt);
 169     vfprintf(stderr, fmt, ap);
 170     va_end(ap);
 171
 172     fprintf(stderr, "\nqerror: call at %s:%d\n", qerr->file, qerr->linenr);
 173     abort();
 174 }
 175
 176 static void qerror_set_data(QError *qerr, const char *fmt, va_list *va)
 177 {
 178     QObject *obj;
 179
 180     obj = qobject_from_jsonv(fmt, va);
 181     if (!obj) {
 182         qerror_abort(qerr, "invalid format '%s'", fmt);
 183     }
 184     if (qobject_type(obj) != QTYPE_QDICT) {
 185         qerror_abort(qerr, "error format is not a QDict '%s'", fmt);
 186     }
 187
 188     qerr->error = qobject_to_qdict(obj);
 189
 190     obj = qdict_get(qerr->error, "class");
 191     if (!obj) {
 192         qerror_abort(qerr, "missing 'class' key in '%s'", fmt);
 193     }
 194     if (qobject_type(obj) != QTYPE_QSTRING) {
 195         qerror_abort(qerr, "'class' key value should be a QString");
 196     }
 197
 198     obj = qdict_get(qerr->error, "data");
 199     if (!obj) {
 200         qerror_abort(qerr, "missing 'data' key in '%s'", fmt);
 201     }
 202     if (qobject_type(obj) != QTYPE_QDICT) {
 203         qerror_abort(qerr, "'data' key value should be a QDICT");
 204     }
 205 }
 206
 207 static void qerror_set_desc(QError *qerr, const char *fmt)
 208 {
 209     int i;
 210
 211     // FIXME: inefficient loop
 212
 213     for (i = 0; qerror_table[i].error_fmt; i++) {
 214         if (strcmp(qerror_table[i].error_fmt, fmt) == 0) {
 215             qerr->entry = &qerror_table[i];
 216             return;
 217         }
 218     }
 219
 220     qerror_abort(qerr, "error format '%s' not found", fmt);
 221 }
 222
 223 /**
 224  * qerror_from_info(): Create a new QError from error information
 225  *
 226  * The information consists of:
 227  *
 228  * - file   the file name of where the error occurred
 229  * - linenr the line number of where the error occurred
 230  * - func   the function name of where the error occurred
 231  * - fmt    JSON printf-like dictionary, there must exist keys 'class' and
 232  *          'data'
 233  * - va     va_list of all arguments specified by fmt
 234  *
 235  * Return strong reference.
 236  */
 237 QError *qerror_from_info(const char *file, int linenr, const char *func,
 238                          const char *fmt, va_list *va)
 239 {
 240     QError *qerr;
 241
 242     qerr = qerror_new();
 243     loc_save(&qerr->loc);
 244     qerr->linenr = linenr;
 245     qerr->file = file;
 246     qerr->func = func;
 247
 248     if (!fmt) {
 249         qerror_abort(qerr, "QDict not specified");
 250     }
 251
 252     qerror_set_data(qerr, fmt, va);
 253     qerror_set_desc(qerr, fmt);
 254
 255     return qerr;
 256 }
 257
 258 static void parse_error(const QError *qerror, int c)
 259 {
 260     qerror_abort(qerror, "expected '%c' in '%s'", c, qerror->entry->desc);
 261 }
 262
 263 static const char *append_field(QString *outstr, const QError *qerror,
 264                                 const char *start)
 265 {
 266     QObject *obj;
 267     QDict *qdict;
 268     QString *key_qs;
 269     const char *end, *key;
 270
 271     if (*start != '%')
 272         parse_error(qerror, '%');
 273     start++;
 274     if (*start != '(')
 275         parse_error(qerror, '(');
 276     start++;
 277
 278     end = strchr(start, ')');
 279     if (!end)
 280         parse_error(qerror, ')');
 281
 282     key_qs = qstring_from_substr(start, 0, end - start - 1);
 283     key = qstring_get_str(key_qs);
 284
 285     qdict = qobject_to_qdict(qdict_get(qerror->error, "data"));
 286     obj = qdict_get(qdict, key);
 287     if (!obj) {
 288         qerror_abort(qerror, "key '%s' not found in QDict", key);
 289     }
 290
 291     switch (qobject_type(obj)) {
 292         case QTYPE_QSTRING:
 293             qstring_append(outstr, qdict_get_str(qdict, key));
 294             break;
 295         case QTYPE_QINT:
 296             qstring_append_int(outstr, qdict_get_int(qdict, key));
 297             break;
 298         default:
 299             qerror_abort(qerror, "invalid type '%c'", qobject_type(obj));
 300     }
 301
 302     QDECREF(key_qs);
 303     return ++end;
 304 }
 305
 306 /**
 307  * qerror_human(): Format QError data into human-readable string.
 308  *
 309  * Formats according to member 'desc' of the specified QError object.
 310  */
 311 QString *qerror_human(const QError *qerror)
 312 {
 313     const char *p;
 314     QString *qstring;
 315
 316     assert(qerror->entry != NULL);
 317
 318     qstring = qstring_new();
 319
 320     for (p = qerror->entry->desc; *p != '\0';) {
 321         if (*p != '%') {
 322             qstring_append_chr(qstring, *p++);
 323         } else if (*(p + 1) == '%') {
 324             qstring_append_chr(qstring, '%');
 325             p += 2;
 326         } else {
 327             p = append_field(qstring, qerror, p);
 328         }
 329     }
 330
 331     return qstring;
 332 }
 333
 334 /**
 335  * qerror_print(): Print QError data
 336  *
 337  * This function will print the member 'desc' of the specified QError object,
 338  * it uses error_report() for this, so that the output is routed to the right
 339  * place (ie. stderr or Monitor's device).
 340  */
 341 void qerror_print(QError *qerror)
 342 {
 343     QString *qstring = qerror_human(qerror);
 344     loc_push_restore(&qerror->loc);
 345     error_report("%s", qstring_get_str(qstring));
 346     loc_pop(&qerror->loc);
 347     QDECREF(qstring);
 348 }
 349
 350 /**
 351  * qobject_to_qerror(): Convert a QObject into a QError
 352  */
 353 QError *qobject_to_qerror(const QObject *obj)
 354 {
 355     if (qobject_type(obj) != QTYPE_QERROR) {
 356         return NULL;
 357     }
 358
 359     return container_of(obj, QError, base);
 360 }
 361
 362 /**
 363  * qerror_destroy_obj(): Free all memory allocated by a QError
 364  */
 365 static void qerror_destroy_obj(QObject *obj)
 366 {
 367     QError *qerr;
 368
 369     assert(obj != NULL);
 370     qerr = qobject_to_qerror(obj);
 371
 372     QDECREF(qerr->error);
 373     qemu_free(qerr);
 374 }