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_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_CPU_INDEX,
  85         .desc      = "Invalid CPU index",
  86     },
  87     {
  88         .error_fmt = QERR_INVALID_PARAMETER,
  89         .desc      = "Invalid parameter %(name)",
  90     },
  91     {
  92         .error_fmt = QERR_INVALID_PARAMETER_TYPE,
  93         .desc      = "Invalid parameter type, expected: %(expected)",
  94     },
  95     {
  96         .error_fmt = QERR_INVALID_PASSWORD,
  97         .desc      = "The entered password is invalid",
  98     },
  99     {
 100         .error_fmt = QERR_JSON_PARSING,
 101         .desc      = "Invalid JSON syntax",
 102     },
 103     {
 104         .error_fmt = QERR_KVM_MISSING_CAP,
 105         .desc      = "Using KVM without %(capability), %(feature) unavailable",
 106     },
 107     {
 108         .error_fmt = QERR_MISSING_PARAMETER,
 109         .desc      = "Parameter %(name) is missing",
 110     },
 111     {
 112         .error_fmt = QERR_QMP_BAD_INPUT_OBJECT,
 113         .desc      = "Bad QMP input object",
 114     },
 115     {
 116         .error_fmt = QERR_SET_PASSWD_FAILED,
 117         .desc      = "Could not set password",
 118     },
 119     {
 120         .error_fmt = QERR_TOO_MANY_FILES,
 121         .desc      = "Too many open files",
 122     },
 123     {
 124         .error_fmt = QERR_UNDEFINED_ERROR,
 125         .desc      = "An undefined error has ocurred",
 126     },
 127     {
 128         .error_fmt = QERR_VNC_SERVER_FAILED,
 129         .desc      = "Could not start VNC server on %(target)",
 130     },
 131     {}
 132 };
 133
 134 /**
 135  * qerror_new(): Create a new QError
 136  *
 137  * Return strong reference.
 138  */
 139 QError *qerror_new(void)
 140 {
 141     QError *qerr;
 142
 143     qerr = qemu_mallocz(sizeof(*qerr));
 144     QOBJECT_INIT(qerr, &qerror_type);
 145
 146     return qerr;
 147 }
 148
 149 static void qerror_abort(const QError *qerr, const char *fmt, ...)
 150 {
 151     va_list ap;
 152
 153     fprintf(stderr, "qerror: bad call in function '%s':\n", qerr->func);
 154     fprintf(stderr, "qerror: -> ");
 155
 156     va_start(ap, fmt);
 157     vfprintf(stderr, fmt, ap);
 158     va_end(ap);
 159
 160     fprintf(stderr, "\nqerror: call at %s:%d\n", qerr->file, qerr->linenr);
 161     abort();
 162 }
 163
 164 static void qerror_set_data(QError *qerr, const char *fmt, va_list *va)
 165 {
 166     QObject *obj;
 167
 168     obj = qobject_from_jsonv(fmt, va);
 169     if (!obj) {
 170         qerror_abort(qerr, "invalid format '%s'", fmt);
 171     }
 172     if (qobject_type(obj) != QTYPE_QDICT) {
 173         qerror_abort(qerr, "error format is not a QDict '%s'", fmt);
 174     }
 175
 176     qerr->error = qobject_to_qdict(obj);
 177
 178     obj = qdict_get(qerr->error, "class");
 179     if (!obj) {
 180         qerror_abort(qerr, "missing 'class' key in '%s'", fmt);
 181     }
 182     if (qobject_type(obj) != QTYPE_QSTRING) {
 183         qerror_abort(qerr, "'class' key value should be a QString");
 184     }
 185
 186     obj = qdict_get(qerr->error, "data");
 187     if (!obj) {
 188         qerror_abort(qerr, "missing 'data' key in '%s'", fmt);
 189     }
 190     if (qobject_type(obj) != QTYPE_QDICT) {
 191         qerror_abort(qerr, "'data' key value should be a QDICT");
 192     }
 193 }
 194
 195 static void qerror_set_desc(QError *qerr, const char *fmt)
 196 {
 197     int i;
 198
 199     // FIXME: inefficient loop
 200
 201     for (i = 0; qerror_table[i].error_fmt; i++) {
 202         if (strcmp(qerror_table[i].error_fmt, fmt) == 0) {
 203             qerr->entry = &qerror_table[i];
 204             return;
 205         }
 206     }
 207
 208     qerror_abort(qerr, "error format '%s' not found", fmt);
 209 }
 210
 211 /**
 212  * qerror_from_info(): Create a new QError from error information
 213  *
 214  * The information consists of:
 215  *
 216  * - file   the file name of where the error occurred
 217  * - linenr the line number of where the error occurred
 218  * - func   the function name of where the error occurred
 219  * - fmt    JSON printf-like dictionary, there must exist keys 'class' and
 220  *          'data'
 221  * - va     va_list of all arguments specified by fmt
 222  *
 223  * Return strong reference.
 224  */
 225 QError *qerror_from_info(const char *file, int linenr, const char *func,
 226                          const char *fmt, va_list *va)
 227 {
 228     QError *qerr;
 229
 230     qerr = qerror_new();
 231     qerr->linenr = linenr;
 232     qerr->file = file;
 233     qerr->func = func;
 234
 235     if (!fmt) {
 236         qerror_abort(qerr, "QDict not specified");
 237     }
 238
 239     qerror_set_data(qerr, fmt, va);
 240     qerror_set_desc(qerr, fmt);
 241
 242     return qerr;
 243 }
 244
 245 static void parse_error(const QError *qerror, int c)
 246 {
 247     qerror_abort(qerror, "expected '%c' in '%s'", c, qerror->entry->desc);
 248 }
 249
 250 static const char *append_field(QString *outstr, const QError *qerror,
 251                                 const char *start)
 252 {
 253     QObject *obj;
 254     QDict *qdict;
 255     QString *key_qs;
 256     const char *end, *key;
 257
 258     if (*start != '%')
 259         parse_error(qerror, '%');
 260     start++;
 261     if (*start != '(')
 262         parse_error(qerror, '(');
 263     start++;
 264
 265     end = strchr(start, ')');
 266     if (!end)
 267         parse_error(qerror, ')');
 268
 269     key_qs = qstring_from_substr(start, 0, end - start - 1);
 270     key = qstring_get_str(key_qs);
 271
 272     qdict = qobject_to_qdict(qdict_get(qerror->error, "data"));
 273     obj = qdict_get(qdict, key);
 274     if (!obj) {
 275         qerror_abort(qerror, "key '%s' not found in QDict", key);
 276     }
 277
 278     switch (qobject_type(obj)) {
 279         case QTYPE_QSTRING:
 280             qstring_append(outstr, qdict_get_str(qdict, key));
 281             break;
 282         case QTYPE_QINT:
 283             qstring_append_int(outstr, qdict_get_int(qdict, key));
 284             break;
 285         default:
 286             qerror_abort(qerror, "invalid type '%c'", qobject_type(obj));
 287     }
 288
 289     QDECREF(key_qs);
 290     return ++end;
 291 }
 292
 293 /**
 294  * qerror_human(): Format QError data into human-readable string.
 295  *
 296  * Formats according to member 'desc' of the specified QError object.
 297  */
 298 QString *qerror_human(const QError *qerror)
 299 {
 300     const char *p;
 301     QString *qstring;
 302
 303     assert(qerror->entry != NULL);
 304
 305     qstring = qstring_new();
 306
 307     for (p = qerror->entry->desc; *p != '\0';) {
 308         if (*p != '%') {
 309             qstring_append_chr(qstring, *p++);
 310         } else if (*(p + 1) == '%') {
 311             qstring_append_chr(qstring, '%');
 312             p += 2;
 313         } else {
 314             p = append_field(qstring, qerror, p);
 315         }
 316     }
 317
 318     return qstring;
 319 }
 320
 321 /**
 322  * qerror_print(): Print QError data
 323  *
 324  * This function will print the member 'desc' of the specified QError object,
 325  * it uses qemu_error() for this, so that the output is routed to the right
 326  * place (ie. stderr or Monitor's device).
 327  */
 328 void qerror_print(const QError *qerror)
 329 {
 330     QString *qstring = qerror_human(qerror);
 331     qemu_error("%s\n", qstring_get_str(qstring));
 332     QDECREF(qstring);
 333 }
 334
 335 /**
 336  * qobject_to_qerror(): Convert a QObject into a QError
 337  */
 338 QError *qobject_to_qerror(const QObject *obj)
 339 {
 340     if (qobject_type(obj) != QTYPE_QERROR) {
 341         return NULL;
 342     }
 343
 344     return container_of(obj, QError, base);
 345 }
 346
 347 /**
 348  * qerror_destroy_obj(): Free all memory allocated by a QError
 349  */
 350 static void qerror_destroy_obj(QObject *obj)
 351 {
 352     QError *qerr;
 353
 354     assert(obj != NULL);
 355     qerr = qobject_to_qerror(obj);
 356
 357     QDECREF(qerr->error);
 358     qemu_free(qerr);
 359 }