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_NOT_FOUND,
  49         .desc      = "The %(device) device has not been found",
  50     },
  51     {
  52         .error_fmt = QERR_DEVICE_NOT_ACTIVE,
  53         .desc      = "The %(device) device has not been activated by the guest",
  54     },
  55     {
  56         .error_fmt   = QERR_INVALID_PARAMETER_TYPE,
  57         .desc        = "Invalid parameter type, expected: %(expected)",
  58     },
  59     {
  60         .error_fmt   = QERR_INVALID_PASSWORD,
  61         .desc        = "The entered password is invalid",
  62     },
  63     {
  64         .error_fmt = QERR_KVM_MISSING_CAP,
  65         .desc      = "Using KVM without %(capability), %(feature) unavailable",
  66     },
  67     {
  68         .error_fmt = QERR_MISSING_PARAMETER,
  69         .desc      = "Parameter %(name) is missing",
  70     },
  71     {
  72         .error_fmt = QERR_QMP_BAD_INPUT_OBJECT,
  73         .desc      = "Bad QMP input object",
  74     },
  75     {
  76         .error_fmt = QERR_JSON_PARSING,
  77         .desc      = "Invalid JSON synaxt",
  78     },
  79     {
  80         .error_fmt   = QERR_UNDEFINED_ERROR,
  81         .desc        = "An undefined error has ocurred",
  82     },
  83     {}
  84 };
  85
  86 /**
  87  * qerror_new(): Create a new QError
  88  *
  89  * Return strong reference.
  90  */
  91 QError *qerror_new(void)
  92 {
  93     QError *qerr;
  94
  95     qerr = qemu_mallocz(sizeof(*qerr));
  96     QOBJECT_INIT(qerr, &qerror_type);
  97
  98     return qerr;
  99 }
 100
 101 static void qerror_abort(const QError *qerr, const char *fmt, ...)
 102 {
 103     va_list ap;
 104
 105     fprintf(stderr, "qerror: bad call in function '%s':\n", qerr->func);
 106     fprintf(stderr, "qerror: -> ");
 107
 108     va_start(ap, fmt);
 109     vfprintf(stderr, fmt, ap);
 110     va_end(ap);
 111
 112     fprintf(stderr, "\nqerror: call at %s:%d\n", qerr->file, qerr->linenr);
 113     abort();
 114 }
 115
 116 static void qerror_set_data(QError *qerr, const char *fmt, va_list *va)
 117 {
 118     QObject *obj;
 119
 120     obj = qobject_from_jsonv(fmt, va);
 121     if (!obj) {
 122         qerror_abort(qerr, "invalid format '%s'", fmt);
 123     }
 124     if (qobject_type(obj) != QTYPE_QDICT) {
 125         qerror_abort(qerr, "error format is not a QDict '%s'", fmt);
 126     }
 127
 128     qerr->error = qobject_to_qdict(obj);
 129
 130     obj = qdict_get(qerr->error, "class");
 131     if (!obj) {
 132         qerror_abort(qerr, "missing 'class' key in '%s'", fmt);
 133     }
 134     if (qobject_type(obj) != QTYPE_QSTRING) {
 135         qerror_abort(qerr, "'class' key value should be a QString");
 136     }
 137
 138     obj = qdict_get(qerr->error, "data");
 139     if (!obj) {
 140         qerror_abort(qerr, "missing 'data' key in '%s'", fmt);
 141     }
 142     if (qobject_type(obj) != QTYPE_QDICT) {
 143         qerror_abort(qerr, "'data' key value should be a QDICT");
 144     }
 145 }
 146
 147 static void qerror_set_desc(QError *qerr, const char *fmt)
 148 {
 149     int i;
 150
 151     // FIXME: inefficient loop
 152
 153     for (i = 0; qerror_table[i].error_fmt; i++) {
 154         if (strcmp(qerror_table[i].error_fmt, fmt) == 0) {
 155             qerr->entry = &qerror_table[i];
 156             return;
 157         }
 158     }
 159
 160     qerror_abort(qerr, "error format '%s' not found", fmt);
 161 }
 162
 163 /**
 164  * qerror_from_info(): Create a new QError from error information
 165  *
 166  * The information consists of:
 167  *
 168  * - file   the file name of where the error occurred
 169  * - linenr the line number of where the error occurred
 170  * - func   the function name of where the error occurred
 171  * - fmt    JSON printf-like dictionary, there must exist keys 'class' and
 172  *          'data'
 173  * - va     va_list of all arguments specified by fmt
 174  *
 175  * Return strong reference.
 176  */
 177 QError *qerror_from_info(const char *file, int linenr, const char *func,
 178                          const char *fmt, va_list *va)
 179 {
 180     QError *qerr;
 181
 182     qerr = qerror_new();
 183     qerr->linenr = linenr;
 184     qerr->file = file;
 185     qerr->func = func;
 186
 187     if (!fmt) {
 188         qerror_abort(qerr, "QDict not specified");
 189     }
 190
 191     qerror_set_data(qerr, fmt, va);
 192     qerror_set_desc(qerr, fmt);
 193
 194     return qerr;
 195 }
 196
 197 static void parse_error(const QError *qerror, int c)
 198 {
 199     qerror_abort(qerror, "expected '%c' in '%s'", c, qerror->entry->desc);
 200 }
 201
 202 static const char *append_field(QString *outstr, const QError *qerror,
 203                                 const char *start)
 204 {
 205     QObject *obj;
 206     QDict *qdict;
 207     QString *key_qs;
 208     const char *end, *key;
 209
 210     if (*start != '%')
 211         parse_error(qerror, '%');
 212     start++;
 213     if (*start != '(')
 214         parse_error(qerror, '(');
 215     start++;
 216
 217     end = strchr(start, ')');
 218     if (!end)
 219         parse_error(qerror, ')');
 220
 221     key_qs = qstring_from_substr(start, 0, end - start - 1);
 222     key = qstring_get_str(key_qs);
 223
 224     qdict = qobject_to_qdict(qdict_get(qerror->error, "data"));
 225     obj = qdict_get(qdict, key);
 226     if (!obj) {
 227         qerror_abort(qerror, "key '%s' not found in QDict", key);
 228     }
 229
 230     switch (qobject_type(obj)) {
 231         case QTYPE_QSTRING:
 232             qstring_append(outstr, qdict_get_str(qdict, key));
 233             break;
 234         case QTYPE_QINT:
 235             qstring_append_int(outstr, qdict_get_int(qdict, key));
 236             break;
 237         default:
 238             qerror_abort(qerror, "invalid type '%c'", qobject_type(obj));
 239     }
 240
 241     QDECREF(key_qs);
 242     return ++end;
 243 }
 244
 245 /**
 246  * qerror_print(): Print QError data
 247  *
 248  * This function will print the member 'desc' of the specified QError object,
 249  * it uses qemu_error() for this, so that the output is routed to the right
 250  * place (ie. stderr or Monitor's device).
 251  */
 252 void qerror_print(const QError *qerror)
 253 {
 254     const char *p;
 255     QString *qstring;
 256
 257     assert(qerror->entry != NULL);
 258
 259     qstring = qstring_new();
 260
 261     for (p = qerror->entry->desc; *p != '\0';) {
 262         if (*p != '%') {
 263             qstring_append_chr(qstring, *p++);
 264         } else if (*(p + 1) == '%') {
 265             qstring_append_chr(qstring, '%');
 266             p += 2;
 267         } else {
 268             p = append_field(qstring, qerror, p);
 269         }
 270     }
 271
 272     qemu_error("%s\n", qstring_get_str(qstring));
 273     QDECREF(qstring);
 274 }
 275
 276 /**
 277  * qobject_to_qerror(): Convert a QObject into a QError
 278  */
 279 QError *qobject_to_qerror(const QObject *obj)
 280 {
 281     if (qobject_type(obj) != QTYPE_QERROR) {
 282         return NULL;
 283     }
 284
 285     return container_of(obj, QError, base);
 286 }
 287
 288 /**
 289  * qerror_destroy_obj(): Free all memory allocated by a QError
 290  */
 291 static void qerror_destroy_obj(QObject *obj)
 292 {
 293     QError *qerr;
 294
 295     assert(obj != NULL);
 296     qerr = qobject_to_qerror(obj);
 297
 298     QDECREF(qerr->error);
 299     qemu_free(qerr);
 300 }