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