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_FD_NOT_FOUND,
  69         .desc      = "Failed to find file descriptor named %(name)",
  70     },
  71     {
  72         .error_fmt = QERR_FD_NOT_SUPPLIED,
  73         .desc      = "No file descriptor supplied via SCM_RIGHTS",
  74     },
  75     {
  76         .error_fmt = QERR_INVALID_BLOCK_FORMAT,
  77         .desc      = "Invalid block format %(name)",
  78     },
  79     {
  80         .error_fmt = QERR_INVALID_PARAMETER_TYPE,
  81         .desc      = "Invalid parameter type, expected: %(expected)",
  82     },
  83     {
  84         .error_fmt = QERR_INVALID_PASSWORD,
  85         .desc      = "The entered password is invalid",
  86     },
  87     {
  88         .error_fmt = QERR_JSON_PARSING,
  89         .desc      = "Invalid JSON syntax",
  90     },
  91     {
  92         .error_fmt = QERR_KVM_MISSING_CAP,
  93         .desc      = "Using KVM without %(capability), %(feature) unavailable",
  94     },
  95     {
  96         .error_fmt = QERR_MISSING_PARAMETER,
  97         .desc      = "Parameter %(name) is missing",
  98     },
  99     {
 100         .error_fmt = QERR_QMP_BAD_INPUT_OBJECT,
 101         .desc      = "Bad QMP input object",
 102     },
 103     {
 104         .error_fmt = QERR_SET_PASSWD_FAILED,
 105         .desc      = "Could not set password",
 106     },
 107     {
 108         .error_fmt = QERR_UNDEFINED_ERROR,
 109         .desc      = "An undefined error has ocurred",
 110     },
 111     {
 112         .error_fmt = QERR_VNC_SERVER_FAILED,
 113         .desc      = "Could not start VNC server on %(target)",
 114     },
 115     {}
 116 };
 117
 118 /**
 119  * qerror_new(): Create a new QError
 120  *
 121  * Return strong reference.
 122  */
 123 QError *qerror_new(void)
 124 {
 125     QError *qerr;
 126
 127     qerr = qemu_mallocz(sizeof(*qerr));
 128     QOBJECT_INIT(qerr, &qerror_type);
 129
 130     return qerr;
 131 }
 132
 133 static void qerror_abort(const QError *qerr, const char *fmt, ...)
 134 {
 135     va_list ap;
 136
 137     fprintf(stderr, "qerror: bad call in function '%s':\n", qerr->func);
 138     fprintf(stderr, "qerror: -> ");
 139
 140     va_start(ap, fmt);
 141     vfprintf(stderr, fmt, ap);
 142     va_end(ap);
 143
 144     fprintf(stderr, "\nqerror: call at %s:%d\n", qerr->file, qerr->linenr);
 145     abort();
 146 }
 147
 148 static void qerror_set_data(QError *qerr, const char *fmt, va_list *va)
 149 {
 150     QObject *obj;
 151
 152     obj = qobject_from_jsonv(fmt, va);
 153     if (!obj) {
 154         qerror_abort(qerr, "invalid format '%s'", fmt);
 155     }
 156     if (qobject_type(obj) != QTYPE_QDICT) {
 157         qerror_abort(qerr, "error format is not a QDict '%s'", fmt);
 158     }
 159
 160     qerr->error = qobject_to_qdict(obj);
 161
 162     obj = qdict_get(qerr->error, "class");
 163     if (!obj) {
 164         qerror_abort(qerr, "missing 'class' key in '%s'", fmt);
 165     }
 166     if (qobject_type(obj) != QTYPE_QSTRING) {
 167         qerror_abort(qerr, "'class' key value should be a QString");
 168     }
 169
 170     obj = qdict_get(qerr->error, "data");
 171     if (!obj) {
 172         qerror_abort(qerr, "missing 'data' key in '%s'", fmt);
 173     }
 174     if (qobject_type(obj) != QTYPE_QDICT) {
 175         qerror_abort(qerr, "'data' key value should be a QDICT");
 176     }
 177 }
 178
 179 static void qerror_set_desc(QError *qerr, const char *fmt)
 180 {
 181     int i;
 182
 183     // FIXME: inefficient loop
 184
 185     for (i = 0; qerror_table[i].error_fmt; i++) {
 186         if (strcmp(qerror_table[i].error_fmt, fmt) == 0) {
 187             qerr->entry = &qerror_table[i];
 188             return;
 189         }
 190     }
 191
 192     qerror_abort(qerr, "error format '%s' not found", fmt);
 193 }
 194
 195 /**
 196  * qerror_from_info(): Create a new QError from error information
 197  *
 198  * The information consists of:
 199  *
 200  * - file   the file name of where the error occurred
 201  * - linenr the line number of where the error occurred
 202  * - func   the function name of where the error occurred
 203  * - fmt    JSON printf-like dictionary, there must exist keys 'class' and
 204  *          'data'
 205  * - va     va_list of all arguments specified by fmt
 206  *
 207  * Return strong reference.
 208  */
 209 QError *qerror_from_info(const char *file, int linenr, const char *func,
 210                          const char *fmt, va_list *va)
 211 {
 212     QError *qerr;
 213
 214     qerr = qerror_new();
 215     qerr->linenr = linenr;
 216     qerr->file = file;
 217     qerr->func = func;
 218
 219     if (!fmt) {
 220         qerror_abort(qerr, "QDict not specified");
 221     }
 222
 223     qerror_set_data(qerr, fmt, va);
 224     qerror_set_desc(qerr, fmt);
 225
 226     return qerr;
 227 }
 228
 229 static void parse_error(const QError *qerror, int c)
 230 {
 231     qerror_abort(qerror, "expected '%c' in '%s'", c, qerror->entry->desc);
 232 }
 233
 234 static const char *append_field(QString *outstr, const QError *qerror,
 235                                 const char *start)
 236 {
 237     QObject *obj;
 238     QDict *qdict;
 239     QString *key_qs;
 240     const char *end, *key;
 241
 242     if (*start != '%')
 243         parse_error(qerror, '%');
 244     start++;
 245     if (*start != '(')
 246         parse_error(qerror, '(');
 247     start++;
 248
 249     end = strchr(start, ')');
 250     if (!end)
 251         parse_error(qerror, ')');
 252
 253     key_qs = qstring_from_substr(start, 0, end - start - 1);
 254     key = qstring_get_str(key_qs);
 255
 256     qdict = qobject_to_qdict(qdict_get(qerror->error, "data"));
 257     obj = qdict_get(qdict, key);
 258     if (!obj) {
 259         qerror_abort(qerror, "key '%s' not found in QDict", key);
 260     }
 261
 262     switch (qobject_type(obj)) {
 263         case QTYPE_QSTRING:
 264             qstring_append(outstr, qdict_get_str(qdict, key));
 265             break;
 266         case QTYPE_QINT:
 267             qstring_append_int(outstr, qdict_get_int(qdict, key));
 268             break;
 269         default:
 270             qerror_abort(qerror, "invalid type '%c'", qobject_type(obj));
 271     }
 272
 273     QDECREF(key_qs);
 274     return ++end;
 275 }
 276
 277 /**
 278  * qerror_print(): Print QError data
 279  *
 280  * This function will print the member 'desc' of the specified QError object,
 281  * it uses qemu_error() for this, so that the output is routed to the right
 282  * place (ie. stderr or Monitor's device).
 283  */
 284 void qerror_print(const QError *qerror)
 285 {
 286     const char *p;
 287     QString *qstring;
 288
 289     assert(qerror->entry != NULL);
 290
 291     qstring = qstring_new();
 292
 293     for (p = qerror->entry->desc; *p != '\0';) {
 294         if (*p != '%') {
 295             qstring_append_chr(qstring, *p++);
 296         } else if (*(p + 1) == '%') {
 297             qstring_append_chr(qstring, '%');
 298             p += 2;
 299         } else {
 300             p = append_field(qstring, qerror, p);
 301         }
 302     }
 303
 304     qemu_error("%s\n", qstring_get_str(qstring));
 305     QDECREF(qstring);
 306 }
 307
 308 /**
 309  * qobject_to_qerror(): Convert a QObject into a QError
 310  */
 311 QError *qobject_to_qerror(const QObject *obj)
 312 {
 313     if (qobject_type(obj) != QTYPE_QERROR) {
 314         return NULL;
 315     }
 316
 317     return container_of(obj, QError, base);
 318 }
 319
 320 /**
 321  * qerror_destroy_obj(): Free all memory allocated by a QError
 322  */
 323 static void qerror_destroy_obj(QObject *obj)
 324 {
 325     QError *qerr;
 326
 327     assert(obj != NULL);
 328     qerr = qobject_to_qerror(obj);
 329
 330     QDECREF(qerr->error);
 331     qemu_free(qerr);
 332 }