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