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