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_NOT_FOUND,
  53         .desc      = "The %(device) device has not been found",
  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_INVALID_PARAMETER_TYPE,
  61         .desc        = "Invalid parameter type, expected: %(expected)",
  62     },
  63     {
  64         .error_fmt   = QERR_INVALID_PASSWORD,
  65         .desc        = "The entered password is invalid",
  66     },
  67     {
  68         .error_fmt = QERR_KVM_MISSING_CAP,
  69         .desc      = "Using KVM without %(capability), %(feature) unavailable",
  70     },
  71     {
  72         .error_fmt = QERR_MISSING_PARAMETER,
  73         .desc      = "Parameter %(name) is missing",
  74     },
  75     {
  76         .error_fmt = QERR_QMP_BAD_INPUT_OBJECT,
  77         .desc      = "Bad QMP input object",
  78     },
  79     {
  80         .error_fmt = QERR_JSON_PARSING,
  81         .desc      = "Invalid JSON synaxt",
  82     },
  83     {
  84         .error_fmt   = QERR_UNDEFINED_ERROR,
  85         .desc        = "An undefined error has ocurred",
  86     },
  87     {}
  88 };
  89
  90 /**
  91  * qerror_new(): Create a new QError
  92  *
  93  * Return strong reference.
  94  */
  95 QError *qerror_new(void)
  96 {
  97     QError *qerr;
  98
  99     qerr = qemu_mallocz(sizeof(*qerr));
 100     QOBJECT_INIT(qerr, &qerror_type);
 101
 102     return qerr;
 103 }
 104
 105 static void qerror_abort(const QError *qerr, const char *fmt, ...)
 106 {
 107     va_list ap;
 108
 109     fprintf(stderr, "qerror: bad call in function '%s':\n", qerr->func);
 110     fprintf(stderr, "qerror: -> ");
 111
 112     va_start(ap, fmt);
 113     vfprintf(stderr, fmt, ap);
 114     va_end(ap);
 115
 116     fprintf(stderr, "\nqerror: call at %s:%d\n", qerr->file, qerr->linenr);
 117     abort();
 118 }
 119
 120 static void qerror_set_data(QError *qerr, const char *fmt, va_list *va)
 121 {
 122     QObject *obj;
 123
 124     obj = qobject_from_jsonv(fmt, va);
 125     if (!obj) {
 126         qerror_abort(qerr, "invalid format '%s'", fmt);
 127     }
 128     if (qobject_type(obj) != QTYPE_QDICT) {
 129         qerror_abort(qerr, "error format is not a QDict '%s'", fmt);
 130     }
 131
 132     qerr->error = qobject_to_qdict(obj);
 133
 134     obj = qdict_get(qerr->error, "class");
 135     if (!obj) {
 136         qerror_abort(qerr, "missing 'class' key in '%s'", fmt);
 137     }
 138     if (qobject_type(obj) != QTYPE_QSTRING) {
 139         qerror_abort(qerr, "'class' key value should be a QString");
 140     }
 141
 142     obj = qdict_get(qerr->error, "data");
 143     if (!obj) {
 144         qerror_abort(qerr, "missing 'data' key in '%s'", fmt);
 145     }
 146     if (qobject_type(obj) != QTYPE_QDICT) {
 147         qerror_abort(qerr, "'data' key value should be a QDICT");
 148     }
 149 }
 150
 151 static void qerror_set_desc(QError *qerr, const char *fmt)
 152 {
 153     int i;
 154
 155     // FIXME: inefficient loop
 156
 157     for (i = 0; qerror_table[i].error_fmt; i++) {
 158         if (strcmp(qerror_table[i].error_fmt, fmt) == 0) {
 159             qerr->entry = &qerror_table[i];
 160             return;
 161         }
 162     }
 163
 164     qerror_abort(qerr, "error format '%s' not found", fmt);
 165 }
 166
 167 /**
 168  * qerror_from_info(): Create a new QError from error information
 169  *
 170  * The information consists of:
 171  *
 172  * - file   the file name of where the error occurred
 173  * - linenr the line number of where the error occurred
 174  * - func   the function name of where the error occurred
 175  * - fmt    JSON printf-like dictionary, there must exist keys 'class' and
 176  *          'data'
 177  * - va     va_list of all arguments specified by fmt
 178  *
 179  * Return strong reference.
 180  */
 181 QError *qerror_from_info(const char *file, int linenr, const char *func,
 182                          const char *fmt, va_list *va)
 183 {
 184     QError *qerr;
 185
 186     qerr = qerror_new();
 187     qerr->linenr = linenr;
 188     qerr->file = file;
 189     qerr->func = func;
 190
 191     if (!fmt) {
 192         qerror_abort(qerr, "QDict not specified");
 193     }
 194
 195     qerror_set_data(qerr, fmt, va);
 196     qerror_set_desc(qerr, fmt);
 197
 198     return qerr;
 199 }
 200
 201 static void parse_error(const QError *qerror, int c)
 202 {
 203     qerror_abort(qerror, "expected '%c' in '%s'", c, qerror->entry->desc);
 204 }
 205
 206 static const char *append_field(QString *outstr, const QError *qerror,
 207                                 const char *start)
 208 {
 209     QObject *obj;
 210     QDict *qdict;
 211     QString *key_qs;
 212     const char *end, *key;
 213
 214     if (*start != '%')
 215         parse_error(qerror, '%');
 216     start++;
 217     if (*start != '(')
 218         parse_error(qerror, '(');
 219     start++;
 220
 221     end = strchr(start, ')');
 222     if (!end)
 223         parse_error(qerror, ')');
 224
 225     key_qs = qstring_from_substr(start, 0, end - start - 1);
 226     key = qstring_get_str(key_qs);
 227
 228     qdict = qobject_to_qdict(qdict_get(qerror->error, "data"));
 229     obj = qdict_get(qdict, key);
 230     if (!obj) {
 231         qerror_abort(qerror, "key '%s' not found in QDict", key);
 232     }
 233
 234     switch (qobject_type(obj)) {
 235         case QTYPE_QSTRING:
 236             qstring_append(outstr, qdict_get_str(qdict, key));
 237             break;
 238         case QTYPE_QINT:
 239             qstring_append_int(outstr, qdict_get_int(qdict, key));
 240             break;
 241         default:
 242             qerror_abort(qerror, "invalid type '%c'", qobject_type(obj));
 243     }
 244
 245     QDECREF(key_qs);
 246     return ++end;
 247 }
 248
 249 /**
 250  * qerror_print(): Print QError data
 251  *
 252  * This function will print the member 'desc' of the specified QError object,
 253  * it uses qemu_error() for this, so that the output is routed to the right
 254  * place (ie. stderr or Monitor's device).
 255  */
 256 void qerror_print(const QError *qerror)
 257 {
 258     const char *p;
 259     QString *qstring;
 260
 261     assert(qerror->entry != NULL);
 262
 263     qstring = qstring_new();
 264
 265     for (p = qerror->entry->desc; *p != '\0';) {
 266         if (*p != '%') {
 267             qstring_append_chr(qstring, *p++);
 268         } else if (*(p + 1) == '%') {
 269             qstring_append_chr(qstring, '%');
 270             p += 2;
 271         } else {
 272             p = append_field(qstring, qerror, p);
 273         }
 274     }
 275
 276     qemu_error("%s\n", qstring_get_str(qstring));
 277     QDECREF(qstring);
 278 }
 279
 280 /**
 281  * qobject_to_qerror(): Convert a QObject into a QError
 282  */
 283 QError *qobject_to_qerror(const QObject *obj)
 284 {
 285     if (qobject_type(obj) != QTYPE_QERROR) {
 286         return NULL;
 287     }
 288
 289     return container_of(obj, QError, base);
 290 }
 291
 292 /**
 293  * qerror_destroy_obj(): Free all memory allocated by a QError
 294  */
 295 static void qerror_destroy_obj(QObject *obj)
 296 {
 297     QError *qerr;
 298
 299     assert(obj != NULL);
 300     qerr = qobject_to_qerror(obj);
 301
 302     QDECREF(qerr->error);
 303     qemu_free(qerr);
 304 }