Annotation of qemu/qerror.c, revision 1.1.1.1

1.1       root        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,
                     81:         .desc      = "Invalid parameter %(name)",
                     82:     },
                     83:     {
                     84:         .error_fmt = QERR_INVALID_PARAMETER_TYPE,
                     85:         .desc      = "Invalid parameter type, expected: %(expected)",
                     86:     },
                     87:     {
                     88:         .error_fmt = QERR_INVALID_PASSWORD,
                     89:         .desc      = "The entered password is invalid",
                     90:     },
                     91:     {
                     92:         .error_fmt = QERR_JSON_PARSING,
                     93:         .desc      = "Invalid JSON syntax",
                     94:     },
                     95:     {
                     96:         .error_fmt = QERR_KVM_MISSING_CAP,
                     97:         .desc      = "Using KVM without %(capability), %(feature) unavailable",
                     98:     },
                     99:     {
                    100:         .error_fmt = QERR_MISSING_PARAMETER,
                    101:         .desc      = "Parameter %(name) is missing",
                    102:     },
                    103:     {
                    104:         .error_fmt = QERR_QMP_BAD_INPUT_OBJECT,
                    105:         .desc      = "Bad QMP input object",
                    106:     },
                    107:     {
                    108:         .error_fmt = QERR_SET_PASSWD_FAILED,
                    109:         .desc      = "Could not set password",
                    110:     },
                    111:     {
                    112:         .error_fmt = QERR_TOO_MANY_FILES,
                    113:         .desc      = "Too many open files",
                    114:     },
                    115:     {
                    116:         .error_fmt = QERR_UNDEFINED_ERROR,
                    117:         .desc      = "An undefined error has ocurred",
                    118:     },
                    119:     {
                    120:         .error_fmt = QERR_VNC_SERVER_FAILED,
                    121:         .desc      = "Could not start VNC server on %(target)",
                    122:     },
                    123:     {}
                    124: };
                    125: 
                    126: /**
                    127:  * qerror_new(): Create a new QError
                    128:  *
                    129:  * Return strong reference.
                    130:  */
                    131: QError *qerror_new(void)
                    132: {
                    133:     QError *qerr;
                    134: 
                    135:     qerr = qemu_mallocz(sizeof(*qerr));
                    136:     QOBJECT_INIT(qerr, &qerror_type);
                    137: 
                    138:     return qerr;
                    139: }
                    140: 
                    141: static void qerror_abort(const QError *qerr, const char *fmt, ...)
                    142: {
                    143:     va_list ap;
                    144: 
                    145:     fprintf(stderr, "qerror: bad call in function '%s':\n", qerr->func);
                    146:     fprintf(stderr, "qerror: -> ");
                    147: 
                    148:     va_start(ap, fmt);
                    149:     vfprintf(stderr, fmt, ap);
                    150:     va_end(ap);
                    151: 
                    152:     fprintf(stderr, "\nqerror: call at %s:%d\n", qerr->file, qerr->linenr);
                    153:     abort();
                    154: }
                    155: 
                    156: static void qerror_set_data(QError *qerr, const char *fmt, va_list *va)
                    157: {
                    158:     QObject *obj;
                    159: 
                    160:     obj = qobject_from_jsonv(fmt, va);
                    161:     if (!obj) {
                    162:         qerror_abort(qerr, "invalid format '%s'", fmt);
                    163:     }
                    164:     if (qobject_type(obj) != QTYPE_QDICT) {
                    165:         qerror_abort(qerr, "error format is not a QDict '%s'", fmt);
                    166:     }
                    167: 
                    168:     qerr->error = qobject_to_qdict(obj);
                    169: 
                    170:     obj = qdict_get(qerr->error, "class");
                    171:     if (!obj) {
                    172:         qerror_abort(qerr, "missing 'class' key in '%s'", fmt);
                    173:     }
                    174:     if (qobject_type(obj) != QTYPE_QSTRING) {
                    175:         qerror_abort(qerr, "'class' key value should be a QString");
                    176:     }
                    177:     
                    178:     obj = qdict_get(qerr->error, "data");
                    179:     if (!obj) {
                    180:         qerror_abort(qerr, "missing 'data' key in '%s'", fmt);
                    181:     }
                    182:     if (qobject_type(obj) != QTYPE_QDICT) {
                    183:         qerror_abort(qerr, "'data' key value should be a QDICT");
                    184:     }
                    185: }
                    186: 
                    187: static void qerror_set_desc(QError *qerr, const char *fmt)
                    188: {
                    189:     int i;
                    190: 
                    191:     // FIXME: inefficient loop
                    192: 
                    193:     for (i = 0; qerror_table[i].error_fmt; i++) {
                    194:         if (strcmp(qerror_table[i].error_fmt, fmt) == 0) {
                    195:             qerr->entry = &qerror_table[i];
                    196:             return;
                    197:         }
                    198:     }
                    199: 
                    200:     qerror_abort(qerr, "error format '%s' not found", fmt);
                    201: }
                    202: 
                    203: /**
                    204:  * qerror_from_info(): Create a new QError from error information
                    205:  *
                    206:  * The information consists of:
                    207:  *
                    208:  * - file   the file name of where the error occurred
                    209:  * - linenr the line number of where the error occurred
                    210:  * - func   the function name of where the error occurred
                    211:  * - fmt    JSON printf-like dictionary, there must exist keys 'class' and
                    212:  *          'data'
                    213:  * - va     va_list of all arguments specified by fmt
                    214:  *
                    215:  * Return strong reference.
                    216:  */
                    217: QError *qerror_from_info(const char *file, int linenr, const char *func,
                    218:                          const char *fmt, va_list *va)
                    219: {
                    220:     QError *qerr;
                    221: 
                    222:     qerr = qerror_new();
                    223:     qerr->linenr = linenr;
                    224:     qerr->file = file;
                    225:     qerr->func = func;
                    226: 
                    227:     if (!fmt) {
                    228:         qerror_abort(qerr, "QDict not specified");
                    229:     }
                    230: 
                    231:     qerror_set_data(qerr, fmt, va);
                    232:     qerror_set_desc(qerr, fmt);
                    233: 
                    234:     return qerr;
                    235: }
                    236: 
                    237: static void parse_error(const QError *qerror, int c)
                    238: {
                    239:     qerror_abort(qerror, "expected '%c' in '%s'", c, qerror->entry->desc);
                    240: }
                    241: 
                    242: static const char *append_field(QString *outstr, const QError *qerror,
                    243:                                 const char *start)
                    244: {
                    245:     QObject *obj;
                    246:     QDict *qdict;
                    247:     QString *key_qs;
                    248:     const char *end, *key;
                    249: 
                    250:     if (*start != '%')
                    251:         parse_error(qerror, '%');
                    252:     start++;
                    253:     if (*start != '(')
                    254:         parse_error(qerror, '(');
                    255:     start++;
                    256: 
                    257:     end = strchr(start, ')');
                    258:     if (!end)
                    259:         parse_error(qerror, ')');
                    260: 
                    261:     key_qs = qstring_from_substr(start, 0, end - start - 1);
                    262:     key = qstring_get_str(key_qs);
                    263: 
                    264:     qdict = qobject_to_qdict(qdict_get(qerror->error, "data"));
                    265:     obj = qdict_get(qdict, key);
                    266:     if (!obj) {
                    267:         qerror_abort(qerror, "key '%s' not found in QDict", key);
                    268:     }
                    269: 
                    270:     switch (qobject_type(obj)) {
                    271:         case QTYPE_QSTRING:
                    272:             qstring_append(outstr, qdict_get_str(qdict, key));
                    273:             break;
                    274:         case QTYPE_QINT:
                    275:             qstring_append_int(outstr, qdict_get_int(qdict, key));
                    276:             break;
                    277:         default:
                    278:             qerror_abort(qerror, "invalid type '%c'", qobject_type(obj));
                    279:     }
                    280: 
                    281:     QDECREF(key_qs);
                    282:     return ++end;
                    283: }
                    284: 
                    285: /**
                    286:  * qerror_human(): Format QError data into human-readable string.
                    287:  *
                    288:  * Formats according to member 'desc' of the specified QError object.
                    289:  */
                    290: QString *qerror_human(const QError *qerror)
                    291: {
                    292:     const char *p;
                    293:     QString *qstring;
                    294: 
                    295:     assert(qerror->entry != NULL);
                    296: 
                    297:     qstring = qstring_new();
                    298: 
                    299:     for (p = qerror->entry->desc; *p != '\0';) {
                    300:         if (*p != '%') {
                    301:             qstring_append_chr(qstring, *p++);
                    302:         } else if (*(p + 1) == '%') {
                    303:             qstring_append_chr(qstring, '%');
                    304:             p += 2;
                    305:         } else {
                    306:             p = append_field(qstring, qerror, p);
                    307:         }
                    308:     }
                    309: 
                    310:     return qstring;
                    311: }
                    312: 
                    313: /**
                    314:  * qerror_print(): Print QError data
                    315:  *
                    316:  * This function will print the member 'desc' of the specified QError object,
                    317:  * it uses qemu_error() for this, so that the output is routed to the right
                    318:  * place (ie. stderr or Monitor's device).
                    319:  */
                    320: void qerror_print(const QError *qerror)
                    321: {
                    322:     QString *qstring = qerror_human(qerror);
                    323:     qemu_error("%s\n", qstring_get_str(qstring));
                    324:     QDECREF(qstring);
                    325: }
                    326: 
                    327: /**
                    328:  * qobject_to_qerror(): Convert a QObject into a QError
                    329:  */
                    330: QError *qobject_to_qerror(const QObject *obj)
                    331: {
                    332:     if (qobject_type(obj) != QTYPE_QERROR) {
                    333:         return NULL;
                    334:     }
                    335: 
                    336:     return container_of(obj, QError, base);
                    337: }
                    338: 
                    339: /**
                    340:  * qerror_destroy_obj(): Free all memory allocated by a QError
                    341:  */
                    342: static void qerror_destroy_obj(QObject *obj)
                    343: {
                    344:     QError *qerr;
                    345: 
                    346:     assert(obj != NULL);
                    347:     qerr = qobject_to_qerror(obj);
                    348: 
                    349:     QDECREF(qerr->error);
                    350:     qemu_free(qerr);
                    351: }

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