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_INVALID_BLOCK_FORMAT,
  69         .desc      = "Invalid block format %(name)",
  70     },
  71     {
  72         .error_fmt = QERR_INVALID_PARAMETER_TYPE,
  73         .desc      = "Invalid parameter type, expected: %(expected)",
  74     },
  75     {
  76         .error_fmt = QERR_INVALID_PASSWORD,
  77         .desc      = "The entered password is invalid",
  78     },
  79     {
  80         .error_fmt = QERR_JSON_PARSING,
  81         .desc      = "Invalid JSON syntax",
  82     },
  83     {
  84         .error_fmt = QERR_KVM_MISSING_CAP,
  85         .desc      = "Using KVM without %(capability), %(feature) unavailable",
  86     },
  87     {
  88         .error_fmt = QERR_MISSING_PARAMETER,
  89         .desc      = "Parameter %(name) is missing",
  90     },
  91     {
  92         .error_fmt = QERR_QMP_BAD_INPUT_OBJECT,
  93         .desc      = "Bad QMP input object",
  94     },
  95     {
  96         .error_fmt = QERR_UNDEFINED_ERROR,
  97         .desc      = "An undefined error has ocurred",
  98     },
  99     {}
 100 };
 101
 102 /**
 103  * qerror_new(): Create a new QError
 104  *
 105  * Return strong reference.
 106  */
 107 QError *qerror_new(void)
 108 {
 109     QError *qerr;
 110
 111     qerr = qemu_mallocz(sizeof(*qerr));
 112     QOBJECT_INIT(qerr, &qerror_type);
 113
 114     return qerr;
 115 }
 116
 117 static void qerror_abort(const QError *qerr, const char *fmt, ...)
 118 {
 119     va_list ap;
 120
 121     fprintf(stderr, "qerror: bad call in function '%s':\n", qerr->func);
 122     fprintf(stderr, "qerror: -> ");
 123
 124     va_start(ap, fmt);
 125     vfprintf(stderr, fmt, ap);
 126     va_end(ap);
 127
 128     fprintf(stderr, "\nqerror: call at %s:%d\n", qerr->file, qerr->linenr);
 129     abort();
 130 }
 131
 132 static void qerror_set_data(QError *qerr, const char *fmt, va_list *va)
 133 {
 134     QObject *obj;
 135
 136     obj = qobject_from_jsonv(fmt, va);
 137     if (!obj) {
 138         qerror_abort(qerr, "invalid format '%s'", fmt);
 139     }
 140     if (qobject_type(obj) != QTYPE_QDICT) {
 141         qerror_abort(qerr, "error format is not a QDict '%s'", fmt);
 142     }
 143
 144     qerr->error = qobject_to_qdict(obj);
 145
 146     obj = qdict_get(qerr->error, "class");
 147     if (!obj) {
 148         qerror_abort(qerr, "missing 'class' key in '%s'", fmt);
 149     }
 150     if (qobject_type(obj) != QTYPE_QSTRING) {
 151         qerror_abort(qerr, "'class' key value should be a QString");
 152     }
 153
 154     obj = qdict_get(qerr->error, "data");
 155     if (!obj) {
 156         qerror_abort(qerr, "missing 'data' key in '%s'", fmt);
 157     }
 158     if (qobject_type(obj) != QTYPE_QDICT) {
 159         qerror_abort(qerr, "'data' key value should be a QDICT");
 160     }
 161 }
 162
 163 static void qerror_set_desc(QError *qerr, const char *fmt)
 164 {
 165     int i;
 166
 167     // FIXME: inefficient loop
 168
 169     for (i = 0; qerror_table[i].error_fmt; i++) {
 170         if (strcmp(qerror_table[i].error_fmt, fmt) == 0) {
 171             qerr->entry = &qerror_table[i];
 172             return;
 173         }
 174     }
 175
 176     qerror_abort(qerr, "error format '%s' not found", fmt);
 177 }
 178
 179 /**
 180  * qerror_from_info(): Create a new QError from error information
 181  *
 182  * The information consists of:
 183  *
 184  * - file   the file name of where the error occurred
 185  * - linenr the line number of where the error occurred
 186  * - func   the function name of where the error occurred
 187  * - fmt    JSON printf-like dictionary, there must exist keys 'class' and
 188  *          'data'
 189  * - va     va_list of all arguments specified by fmt
 190  *
 191  * Return strong reference.
 192  */
 193 QError *qerror_from_info(const char *file, int linenr, const char *func,
 194                          const char *fmt, va_list *va)
 195 {
 196     QError *qerr;
 197
 198     qerr = qerror_new();
 199     qerr->linenr = linenr;
 200     qerr->file = file;
 201     qerr->func = func;
 202
 203     if (!fmt) {
 204         qerror_abort(qerr, "QDict not specified");
 205     }
 206
 207     qerror_set_data(qerr, fmt, va);
 208     qerror_set_desc(qerr, fmt);
 209
 210     return qerr;
 211 }
 212
 213 static void parse_error(const QError *qerror, int c)
 214 {
 215     qerror_abort(qerror, "expected '%c' in '%s'", c, qerror->entry->desc);
 216 }
 217
 218 static const char *append_field(QString *outstr, const QError *qerror,
 219                                 const char *start)
 220 {
 221     QObject *obj;
 222     QDict *qdict;
 223     QString *key_qs;
 224     const char *end, *key;
 225
 226     if (*start != '%')
 227         parse_error(qerror, '%');
 228     start++;
 229     if (*start != '(')
 230         parse_error(qerror, '(');
 231     start++;
 232
 233     end = strchr(start, ')');
 234     if (!end)
 235         parse_error(qerror, ')');
 236
 237     key_qs = qstring_from_substr(start, 0, end - start - 1);
 238     key = qstring_get_str(key_qs);
 239
 240     qdict = qobject_to_qdict(qdict_get(qerror->error, "data"));
 241     obj = qdict_get(qdict, key);
 242     if (!obj) {
 243         qerror_abort(qerror, "key '%s' not found in QDict", key);
 244     }
 245
 246     switch (qobject_type(obj)) {
 247         case QTYPE_QSTRING:
 248             qstring_append(outstr, qdict_get_str(qdict, key));
 249             break;
 250         case QTYPE_QINT:
 251             qstring_append_int(outstr, qdict_get_int(qdict, key));
 252             break;
 253         default:
 254             qerror_abort(qerror, "invalid type '%c'", qobject_type(obj));
 255     }
 256
 257     QDECREF(key_qs);
 258     return ++end;
 259 }
 260
 261 /**
 262  * qerror_print(): Print QError data
 263  *
 264  * This function will print the member 'desc' of the specified QError object,
 265  * it uses qemu_error() for this, so that the output is routed to the right
 266  * place (ie. stderr or Monitor's device).
 267  */
 268 void qerror_print(const QError *qerror)
 269 {
 270     const char *p;
 271     QString *qstring;
 272
 273     assert(qerror->entry != NULL);
 274
 275     qstring = qstring_new();
 276
 277     for (p = qerror->entry->desc; *p != '\0';) {
 278         if (*p != '%') {
 279             qstring_append_chr(qstring, *p++);
 280         } else if (*(p + 1) == '%') {
 281             qstring_append_chr(qstring, '%');
 282             p += 2;
 283         } else {
 284             p = append_field(qstring, qerror, p);
 285         }
 286     }
 287
 288     qemu_error("%s\n", qstring_get_str(qstring));
 289     QDECREF(qstring);
 290 }
 291
 292 /**
 293  * qobject_to_qerror(): Convert a QObject into a QError
 294  */
 295 QError *qobject_to_qerror(const QObject *obj)
 296 {
 297     if (qobject_type(obj) != QTYPE_QERROR) {
 298         return NULL;
 299     }
 300
 301     return container_of(obj, QError, base);
 302 }
 303
 304 /**
 305  * qerror_destroy_obj(): Free all memory allocated by a QError
 306  */
 307 static void qerror_destroy_obj(QObject *obj)
 308 {
 309     QError *qerr;
 310
 311     assert(obj != NULL);
 312     qerr = qobject_to_qerror(obj);
 313
 314     QDECREF(qerr->error);
 315     qemu_free(qerr);
 316 }