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_INVALID_PARAMETER_TYPE,
  65         .desc      = "Invalid parameter type, expected: %(expected)",
  66     },
  67     {
  68         .error_fmt = QERR_INVALID_PASSWORD,
  69         .desc      = "The entered password is invalid",
  70     },
  71     {
  72         .error_fmt = QERR_JSON_PARSING,
  73         .desc      = "Invalid JSON syntax",
  74     },
  75     {
  76         .error_fmt = QERR_KVM_MISSING_CAP,
  77         .desc      = "Using KVM without %(capability), %(feature) unavailable",
  78     },
  79     {
  80         .error_fmt = QERR_MISSING_PARAMETER,
  81         .desc      = "Parameter %(name) is missing",
  82     },
  83     {
  84         .error_fmt = QERR_QMP_BAD_INPUT_OBJECT,
  85         .desc      = "Bad QMP input object",
  86     },
  87     {
  88         .error_fmt = QERR_UNDEFINED_ERROR,
  89         .desc      = "An undefined error has ocurred",
  90     },
  91     {}
  92 };
  93
  94 /**
  95  * qerror_new(): Create a new QError
  96  *
  97  * Return strong reference.
  98  */
  99 QError *qerror_new(void)
 100 {
 101     QError *qerr;
 102
 103     qerr = qemu_mallocz(sizeof(*qerr));
 104     QOBJECT_INIT(qerr, &qerror_type);
 105
 106     return qerr;
 107 }
 108
 109 static void qerror_abort(const QError *qerr, const char *fmt, ...)
 110 {
 111     va_list ap;
 112
 113     fprintf(stderr, "qerror: bad call in function '%s':\n", qerr->func);
 114     fprintf(stderr, "qerror: -> ");
 115
 116     va_start(ap, fmt);
 117     vfprintf(stderr, fmt, ap);
 118     va_end(ap);
 119
 120     fprintf(stderr, "\nqerror: call at %s:%d\n", qerr->file, qerr->linenr);
 121     abort();
 122 }
 123
 124 static void qerror_set_data(QError *qerr, const char *fmt, va_list *va)
 125 {
 126     QObject *obj;
 127
 128     obj = qobject_from_jsonv(fmt, va);
 129     if (!obj) {
 130         qerror_abort(qerr, "invalid format '%s'", fmt);
 131     }
 132     if (qobject_type(obj) != QTYPE_QDICT) {
 133         qerror_abort(qerr, "error format is not a QDict '%s'", fmt);
 134     }
 135
 136     qerr->error = qobject_to_qdict(obj);
 137
 138     obj = qdict_get(qerr->error, "class");
 139     if (!obj) {
 140         qerror_abort(qerr, "missing 'class' key in '%s'", fmt);
 141     }
 142     if (qobject_type(obj) != QTYPE_QSTRING) {
 143         qerror_abort(qerr, "'class' key value should be a QString");
 144     }
 145
 146     obj = qdict_get(qerr->error, "data");
 147     if (!obj) {
 148         qerror_abort(qerr, "missing 'data' key in '%s'", fmt);
 149     }
 150     if (qobject_type(obj) != QTYPE_QDICT) {
 151         qerror_abort(qerr, "'data' key value should be a QDICT");
 152     }
 153 }
 154
 155 static void qerror_set_desc(QError *qerr, const char *fmt)
 156 {
 157     int i;
 158
 159     // FIXME: inefficient loop
 160
 161     for (i = 0; qerror_table[i].error_fmt; i++) {
 162         if (strcmp(qerror_table[i].error_fmt, fmt) == 0) {
 163             qerr->entry = &qerror_table[i];
 164             return;
 165         }
 166     }
 167
 168     qerror_abort(qerr, "error format '%s' not found", fmt);
 169 }
 170
 171 /**
 172  * qerror_from_info(): Create a new QError from error information
 173  *
 174  * The information consists of:
 175  *
 176  * - file   the file name of where the error occurred
 177  * - linenr the line number of where the error occurred
 178  * - func   the function name of where the error occurred
 179  * - fmt    JSON printf-like dictionary, there must exist keys 'class' and
 180  *          'data'
 181  * - va     va_list of all arguments specified by fmt
 182  *
 183  * Return strong reference.
 184  */
 185 QError *qerror_from_info(const char *file, int linenr, const char *func,
 186                          const char *fmt, va_list *va)
 187 {
 188     QError *qerr;
 189
 190     qerr = qerror_new();
 191     qerr->linenr = linenr;
 192     qerr->file = file;
 193     qerr->func = func;
 194
 195     if (!fmt) {
 196         qerror_abort(qerr, "QDict not specified");
 197     }
 198
 199     qerror_set_data(qerr, fmt, va);
 200     qerror_set_desc(qerr, fmt);
 201
 202     return qerr;
 203 }
 204
 205 static void parse_error(const QError *qerror, int c)
 206 {
 207     qerror_abort(qerror, "expected '%c' in '%s'", c, qerror->entry->desc);
 208 }
 209
 210 static const char *append_field(QString *outstr, const QError *qerror,
 211                                 const char *start)
 212 {
 213     QObject *obj;
 214     QDict *qdict;
 215     QString *key_qs;
 216     const char *end, *key;
 217
 218     if (*start != '%')
 219         parse_error(qerror, '%');
 220     start++;
 221     if (*start != '(')
 222         parse_error(qerror, '(');
 223     start++;
 224
 225     end = strchr(start, ')');
 226     if (!end)
 227         parse_error(qerror, ')');
 228
 229     key_qs = qstring_from_substr(start, 0, end - start - 1);
 230     key = qstring_get_str(key_qs);
 231
 232     qdict = qobject_to_qdict(qdict_get(qerror->error, "data"));
 233     obj = qdict_get(qdict, key);
 234     if (!obj) {
 235         qerror_abort(qerror, "key '%s' not found in QDict", key);
 236     }
 237
 238     switch (qobject_type(obj)) {
 239         case QTYPE_QSTRING:
 240             qstring_append(outstr, qdict_get_str(qdict, key));
 241             break;
 242         case QTYPE_QINT:
 243             qstring_append_int(outstr, qdict_get_int(qdict, key));
 244             break;
 245         default:
 246             qerror_abort(qerror, "invalid type '%c'", qobject_type(obj));
 247     }
 248
 249     QDECREF(key_qs);
 250     return ++end;
 251 }
 252
 253 /**
 254  * qerror_print(): Print QError data
 255  *
 256  * This function will print the member 'desc' of the specified QError object,
 257  * it uses qemu_error() for this, so that the output is routed to the right
 258  * place (ie. stderr or Monitor's device).
 259  */
 260 void qerror_print(const QError *qerror)
 261 {
 262     const char *p;
 263     QString *qstring;
 264
 265     assert(qerror->entry != NULL);
 266
 267     qstring = qstring_new();
 268
 269     for (p = qerror->entry->desc; *p != '\0';) {
 270         if (*p != '%') {
 271             qstring_append_chr(qstring, *p++);
 272         } else if (*(p + 1) == '%') {
 273             qstring_append_chr(qstring, '%');
 274             p += 2;
 275         } else {
 276             p = append_field(qstring, qerror, p);
 277         }
 278     }
 279
 280     qemu_error("%s\n", qstring_get_str(qstring));
 281     QDECREF(qstring);
 282 }
 283
 284 /**
 285  * qobject_to_qerror(): Convert a QObject into a QError
 286  */
 287 QError *qobject_to_qerror(const QObject *obj)
 288 {
 289     if (qobject_type(obj) != QTYPE_QERROR) {
 290         return NULL;
 291     }
 292
 293     return container_of(obj, QError, base);
 294 }
 295
 296 /**
 297  * qerror_destroy_obj(): Free all memory allocated by a QError
 298  */
 299 static void qerror_destroy_obj(QObject *obj)
 300 {
 301     QError *qerr;
 302
 303     assert(obj != NULL);
 304     qerr = qobject_to_qerror(obj);
 305
 306     QDECREF(qerr->error);
 307     qemu_free(qerr);
 308 }