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 "sysemu.h"
  16 #include "qemu-common.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_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      = "The entered password is invalid",
  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_QMP_BAD_INPUT_OBJECT,
 105         .desc      = "Bad QMP input object",
 106     },
 107     {
 108         .error_fmt = QERR_SET_PASSWD_FAILED,
 109         .desc      = "Could not set password",
 110     },
 111     {
 112         .error_fmt = QERR_TOO_MANY_FILES,
 113         .desc      = "Too many open files",
 114     },
 115     {
 116         .error_fmt = QERR_UNDEFINED_ERROR,
 117         .desc      = "An undefined error has ocurred",
 118     },
 119     {
 120         .error_fmt = QERR_VNC_SERVER_FAILED,
 121         .desc      = "Could not start VNC server on %(target)",
 122     },
 123     {}
 124 };
 125
 126 /**
 127  * qerror_new(): Create a new QError
 128  *
 129  * Return strong reference.
 130  */
 131 QError *qerror_new(void)
 132 {
 133     QError *qerr;
 134
 135     qerr = qemu_mallocz(sizeof(*qerr));
 136     QOBJECT_INIT(qerr, &qerror_type);
 137
 138     return qerr;
 139 }
 140
 141 static void qerror_abort(const QError *qerr, const char *fmt, ...)
 142 {
 143     va_list ap;
 144
 145     fprintf(stderr, "qerror: bad call in function '%s':\n", qerr->func);
 146     fprintf(stderr, "qerror: -> ");
 147
 148     va_start(ap, fmt);
 149     vfprintf(stderr, fmt, ap);
 150     va_end(ap);
 151
 152     fprintf(stderr, "\nqerror: call at %s:%d\n", qerr->file, qerr->linenr);
 153     abort();
 154 }
 155
 156 static void qerror_set_data(QError *qerr, const char *fmt, va_list *va)
 157 {
 158     QObject *obj;
 159
 160     obj = qobject_from_jsonv(fmt, va);
 161     if (!obj) {
 162         qerror_abort(qerr, "invalid format '%s'", fmt);
 163     }
 164     if (qobject_type(obj) != QTYPE_QDICT) {
 165         qerror_abort(qerr, "error format is not a QDict '%s'", fmt);
 166     }
 167
 168     qerr->error = qobject_to_qdict(obj);
 169
 170     obj = qdict_get(qerr->error, "class");
 171     if (!obj) {
 172         qerror_abort(qerr, "missing 'class' key in '%s'", fmt);
 173     }
 174     if (qobject_type(obj) != QTYPE_QSTRING) {
 175         qerror_abort(qerr, "'class' key value should be a QString");
 176     }
 177
 178     obj = qdict_get(qerr->error, "data");
 179     if (!obj) {
 180         qerror_abort(qerr, "missing 'data' key in '%s'", fmt);
 181     }
 182     if (qobject_type(obj) != QTYPE_QDICT) {
 183         qerror_abort(qerr, "'data' key value should be a QDICT");
 184     }
 185 }
 186
 187 static void qerror_set_desc(QError *qerr, const char *fmt)
 188 {
 189     int i;
 190
 191     // FIXME: inefficient loop
 192
 193     for (i = 0; qerror_table[i].error_fmt; i++) {
 194         if (strcmp(qerror_table[i].error_fmt, fmt) == 0) {
 195             qerr->entry = &qerror_table[i];
 196             return;
 197         }
 198     }
 199
 200     qerror_abort(qerr, "error format '%s' not found", fmt);
 201 }
 202
 203 /**
 204  * qerror_from_info(): Create a new QError from error information
 205  *
 206  * The information consists of:
 207  *
 208  * - file   the file name of where the error occurred
 209  * - linenr the line number of where the error occurred
 210  * - func   the function name of where the error occurred
 211  * - fmt    JSON printf-like dictionary, there must exist keys 'class' and
 212  *          'data'
 213  * - va     va_list of all arguments specified by fmt
 214  *
 215  * Return strong reference.
 216  */
 217 QError *qerror_from_info(const char *file, int linenr, const char *func,
 218                          const char *fmt, va_list *va)
 219 {
 220     QError *qerr;
 221
 222     qerr = qerror_new();
 223     qerr->linenr = linenr;
 224     qerr->file = file;
 225     qerr->func = func;
 226
 227     if (!fmt) {
 228         qerror_abort(qerr, "QDict not specified");
 229     }
 230
 231     qerror_set_data(qerr, fmt, va);
 232     qerror_set_desc(qerr, fmt);
 233
 234     return qerr;
 235 }
 236
 237 static void parse_error(const QError *qerror, int c)
 238 {
 239     qerror_abort(qerror, "expected '%c' in '%s'", c, qerror->entry->desc);
 240 }
 241
 242 static const char *append_field(QString *outstr, const QError *qerror,
 243                                 const char *start)
 244 {
 245     QObject *obj;
 246     QDict *qdict;
 247     QString *key_qs;
 248     const char *end, *key;
 249
 250     if (*start != '%')
 251         parse_error(qerror, '%');
 252     start++;
 253     if (*start != '(')
 254         parse_error(qerror, '(');
 255     start++;
 256
 257     end = strchr(start, ')');
 258     if (!end)
 259         parse_error(qerror, ')');
 260
 261     key_qs = qstring_from_substr(start, 0, end - start - 1);
 262     key = qstring_get_str(key_qs);
 263
 264     qdict = qobject_to_qdict(qdict_get(qerror->error, "data"));
 265     obj = qdict_get(qdict, key);
 266     if (!obj) {
 267         qerror_abort(qerror, "key '%s' not found in QDict", key);
 268     }
 269
 270     switch (qobject_type(obj)) {
 271         case QTYPE_QSTRING:
 272             qstring_append(outstr, qdict_get_str(qdict, key));
 273             break;
 274         case QTYPE_QINT:
 275             qstring_append_int(outstr, qdict_get_int(qdict, key));
 276             break;
 277         default:
 278             qerror_abort(qerror, "invalid type '%c'", qobject_type(obj));
 279     }
 280
 281     QDECREF(key_qs);
 282     return ++end;
 283 }
 284
 285 /**
 286  * qerror_human(): Format QError data into human-readable string.
 287  *
 288  * Formats according to member 'desc' of the specified QError object.
 289  */
 290 QString *qerror_human(const QError *qerror)
 291 {
 292     const char *p;
 293     QString *qstring;
 294
 295     assert(qerror->entry != NULL);
 296
 297     qstring = qstring_new();
 298
 299     for (p = qerror->entry->desc; *p != '\0';) {
 300         if (*p != '%') {
 301             qstring_append_chr(qstring, *p++);
 302         } else if (*(p + 1) == '%') {
 303             qstring_append_chr(qstring, '%');
 304             p += 2;
 305         } else {
 306             p = append_field(qstring, qerror, p);
 307         }
 308     }
 309
 310     return qstring;
 311 }
 312
 313 /**
 314  * qerror_print(): Print QError data
 315  *
 316  * This function will print the member 'desc' of the specified QError object,
 317  * it uses qemu_error() for this, so that the output is routed to the right
 318  * place (ie. stderr or Monitor's device).
 319  */
 320 void qerror_print(const QError *qerror)
 321 {
 322     QString *qstring = qerror_human(qerror);
 323     qemu_error("%s\n", qstring_get_str(qstring));
 324     QDECREF(qstring);
 325 }
 326
 327 /**
 328  * qobject_to_qerror(): Convert a QObject into a QError
 329  */
 330 QError *qobject_to_qerror(const QObject *obj)
 331 {
 332     if (qobject_type(obj) != QTYPE_QERROR) {
 333         return NULL;
 334     }
 335
 336     return container_of(obj, QError, base);
 337 }
 338
 339 /**
 340  * qerror_destroy_obj(): Free all memory allocated by a QError
 341  */
 342 static void qerror_destroy_obj(QObject *obj)
 343 {
 344     QError *qerr;
 345
 346     assert(obj != NULL);
 347     qerr = qobject_to_qerror(obj);
 348
 349     QDECREF(qerr->error);
 350     qemu_free(qerr);
 351 }