qapi/opts-visitor.c

   1 /*
   2  * Options Visitor
   3  *
   4  * Copyright Red Hat, Inc. 2012-2016
   5  *
   6  * Author: Laszlo Ersek <lersek@redhat.com>
   7  *
   8  * This work is licensed under the terms of the GNU LGPL, version 2.1 or later.
   9  * See the COPYING.LIB file in the top-level directory.
  10  *
  11  */
  12
  13 #include "qemu/osdep.h"
  14 #include "qapi/error.h"
  15 #include "qemu/cutils.h"
  16 #include "qapi/qmp/qerror.h"
  17 #include "qapi/opts-visitor.h"
  18 #include "qemu/queue.h"
  19 #include "qemu/option_int.h"
  20 #include "qapi/visitor-impl.h"
  21
  22
  23 enum ListMode
  24 {
  25     LM_NONE,             /* not traversing a list of repeated options */
  26
  27     LM_IN_PROGRESS,      /*
  28                           * opts_next_list() ready to be called.
  29                           *
  30                           * Generating the next list link will consume the most
  31                           * recently parsed QemuOpt instance of the repeated
  32                           * option.
  33                           *
  34                           * Parsing a value into the list link will examine the
  35                           * next QemuOpt instance of the repeated option, and
  36                           * possibly enter LM_SIGNED_INTERVAL or
  37                           * LM_UNSIGNED_INTERVAL.
  38                           */
  39
  40     LM_SIGNED_INTERVAL,  /*
  41                           * opts_next_list() has been called.
  42                           *
  43                           * Generating the next list link will consume the most
  44                           * recently stored element from the signed interval,
  45                           * parsed from the most recent QemuOpt instance of the
  46                           * repeated option. This may consume QemuOpt itself
  47                           * and return to LM_IN_PROGRESS.
  48                           *
  49                           * Parsing a value into the list link will store the
  50                           * next element of the signed interval.
  51                           */
  52
  53     LM_UNSIGNED_INTERVAL, /* Same as above, only for an unsigned interval. */
  54
  55     LM_TRAVERSED          /*
  56                            * opts_next_list() has been called.
  57                            *
  58                            * No more QemuOpt instance in the list.
  59                            * The traversal has been completed.
  60                            */
  61 };
  62
  63 typedef enum ListMode ListMode;
  64
  65 struct OptsVisitor
  66 {
  67     Visitor visitor;
  68
  69     /* Ownership remains with opts_visitor_new()'s caller. */
  70     const QemuOpts *opts_root;
  71
  72     unsigned depth;
  73
  74     /* Non-null iff depth is positive. Each key is a QemuOpt name. Each value
  75      * is a non-empty GQueue, enumerating all QemuOpt occurrences with that
  76      * name. */
  77     GHashTable *unprocessed_opts;
  78
  79     /* The list currently being traversed with opts_start_list() /
  80      * opts_next_list(). The list must have a struct element type in the
  81      * schema, with a single mandatory scalar member. */
  82     ListMode list_mode;
  83     GQueue *repeated_opts;
  84
  85     /* When parsing a list of repeating options as integers, values of the form
  86      * "a-b", representing a closed interval, are allowed. Elements in the
  87      * range are generated individually.
  88      */
  89     union {
  90         int64_t s;
  91         uint64_t u;
  92     } range_next, range_limit;
  93
  94     /* If "opts_root->id" is set, reinstantiate it as a fake QemuOpt for
  95      * uniformity. Only its "name" and "str" fields are set. "fake_id_opt" does
  96      * not survive or escape the OptsVisitor object.
  97      */
  98     QemuOpt *fake_id_opt;
  99 };
 100
 101
 102 static OptsVisitor *to_ov(Visitor *v)
 103 {
 104     return container_of(v, OptsVisitor, visitor);
 105 }
 106
 107
 108 static void
 109 destroy_list(gpointer list)
 110 {
 111   g_queue_free(list);
 112 }
 113
 114
 115 static void
 116 opts_visitor_insert(GHashTable *unprocessed_opts, const QemuOpt *opt)
 117 {
 118     GQueue *list;
 119
 120     list = g_hash_table_lookup(unprocessed_opts, opt->name);
 121     if (list == NULL) {
 122         list = g_queue_new();
 123
 124         /* GHashTable will never try to free the keys -- we supply NULL as
 125          * "key_destroy_func" in opts_start_struct(). Thus cast away key
 126          * const-ness in order to suppress gcc's warning.
 127          */
 128         g_hash_table_insert(unprocessed_opts, (gpointer)opt->name, list);
 129     }
 130
 131     /* Similarly, destroy_list() doesn't call g_queue_free_full(). */
 132     g_queue_push_tail(list, (gpointer)opt);
 133 }
 134
 135
 136 static bool
 137 opts_start_struct(Visitor *v, const char *name, void **obj,
 138                   size_t size, Error **errp)
 139 {
 140     OptsVisitor *ov = to_ov(v);
 141     const QemuOpt *opt;
 142
 143     if (obj) {
 144         *obj = g_malloc0(size);
 145     }
 146     if (ov->depth++ > 0) {
 147         return true;
 148     }
 149
 150     ov->unprocessed_opts = g_hash_table_new_full(&g_str_hash, &g_str_equal,
 151                                                  NULL, &destroy_list);
 152     QTAILQ_FOREACH(opt, &ov->opts_root->head, next) {
 153         /* ensured by qemu-option.c::opts_do_parse() */
 154         assert(strcmp(opt->name, "id") != 0);
 155
 156         opts_visitor_insert(ov->unprocessed_opts, opt);
 157     }
 158
 159     if (ov->opts_root->id != NULL) {
 160         ov->fake_id_opt = g_malloc0(sizeof *ov->fake_id_opt);
 161
 162         ov->fake_id_opt->name = g_strdup("id");
 163         ov->fake_id_opt->str = g_strdup(ov->opts_root->id);
 164         opts_visitor_insert(ov->unprocessed_opts, ov->fake_id_opt);
 165     }
 166     return true;
 167 }
 168
 169
 170 static bool
 171 opts_check_struct(Visitor *v, Error **errp)
 172 {
 173     OptsVisitor *ov = to_ov(v);
 174     GHashTableIter iter;
 175     GQueue *any;
 176
 177     if (ov->depth > 1) {
 178         return true;
 179     }
 180
 181     /* we should have processed all (distinct) QemuOpt instances */
 182     g_hash_table_iter_init(&iter, ov->unprocessed_opts);
 183     if (g_hash_table_iter_next(&iter, NULL, (void **)&any)) {
 184         const QemuOpt *first;
 185
 186         first = g_queue_peek_head(any);
 187         error_setg(errp, QERR_INVALID_PARAMETER, first->name);
 188         return false;
 189     }
 190     return true;
 191 }
 192
 193
 194 static void
 195 opts_end_struct(Visitor *v, void **obj)
 196 {
 197     OptsVisitor *ov = to_ov(v);
 198
 199     if (--ov->depth > 0) {
 200         return;
 201     }
 202
 203     g_hash_table_destroy(ov->unprocessed_opts);
 204     ov->unprocessed_opts = NULL;
 205     if (ov->fake_id_opt) {
 206         g_free(ov->fake_id_opt->name);
 207         g_free(ov->fake_id_opt->str);
 208         g_free(ov->fake_id_opt);
 209     }
 210     ov->fake_id_opt = NULL;
 211 }
 212
 213
 214 static GQueue *
 215 lookup_distinct(const OptsVisitor *ov, const char *name, Error **errp)
 216 {
 217     GQueue *list;
 218
 219     list = g_hash_table_lookup(ov->unprocessed_opts, name);
 220     if (!list) {
 221         error_setg(errp, QERR_MISSING_PARAMETER, name);
 222     }
 223     return list;
 224 }
 225
 226
 227 static bool
 228 opts_start_list(Visitor *v, const char *name, GenericList **list, size_t size,
 229                 Error **errp)
 230 {
 231     OptsVisitor *ov = to_ov(v);
 232
 233     /* we can't traverse a list in a list */
 234     assert(ov->list_mode == LM_NONE);
 235     /* we don't support visits without a list */
 236     assert(list);
 237     ov->repeated_opts = lookup_distinct(ov, name, errp);
 238     if (!ov->repeated_opts) {
 239         *list = NULL;
 240         return false;
 241     }
 242     ov->list_mode = LM_IN_PROGRESS;
 243     *list = g_malloc0(size);
 244     return true;
 245 }
 246
 247
 248 static GenericList *
 249 opts_next_list(Visitor *v, GenericList *tail, size_t size)
 250 {
 251     OptsVisitor *ov = to_ov(v);
 252
 253     switch (ov->list_mode) {
 254     case LM_TRAVERSED:
 255         return NULL;
 256     case LM_SIGNED_INTERVAL:
 257     case LM_UNSIGNED_INTERVAL:
 258         if (ov->list_mode == LM_SIGNED_INTERVAL) {
 259             if (ov->range_next.s < ov->range_limit.s) {
 260                 ++ov->range_next.s;
 261                 break;
 262             }
 263         } else if (ov->range_next.u < ov->range_limit.u) {
 264             ++ov->range_next.u;
 265             break;
 266         }
 267         ov->list_mode = LM_IN_PROGRESS;
 268         /* range has been completed, fall through in order to pop option */
 269
 270     case LM_IN_PROGRESS: {
 271         const QemuOpt *opt;
 272
 273         opt = g_queue_pop_head(ov->repeated_opts);
 274         if (g_queue_is_empty(ov->repeated_opts)) {
 275             g_hash_table_remove(ov->unprocessed_opts, opt->name);
 276             ov->repeated_opts = NULL;
 277             ov->list_mode = LM_TRAVERSED;
 278             return NULL;
 279         }
 280         break;
 281     }
 282
 283     default:
 284         abort();
 285     }
 286
 287     tail->next = g_malloc0(size);
 288     return tail->next;
 289 }
 290
 291
 292 static bool
 293 opts_check_list(Visitor *v, Error **errp)
 294 {
 295     /*
 296      * Unvisited list elements will be reported later when checking
 297      * whether unvisited struct members remain.
 298      */
 299     return true;
 300 }
 301
 302
 303 static void
 304 opts_end_list(Visitor *v, void **obj)
 305 {
 306     OptsVisitor *ov = to_ov(v);
 307
 308     assert(ov->list_mode == LM_IN_PROGRESS ||
 309            ov->list_mode == LM_SIGNED_INTERVAL ||
 310            ov->list_mode == LM_UNSIGNED_INTERVAL ||
 311            ov->list_mode == LM_TRAVERSED);
 312     ov->repeated_opts = NULL;
 313     ov->list_mode = LM_NONE;
 314 }
 315
 316
 317 static const QemuOpt *
 318 lookup_scalar(const OptsVisitor *ov, const char *name, Error **errp)
 319 {
 320     if (ov->list_mode == LM_NONE) {
 321         GQueue *list;
 322
 323         /* the last occurrence of any QemuOpt takes effect when queried by name
 324          */
 325         list = lookup_distinct(ov, name, errp);
 326         return list ? g_queue_peek_tail(list) : NULL;
 327     }
 328     if (ov->list_mode == LM_TRAVERSED) {
 329         error_setg(errp, "Fewer list elements than expected");
 330         return NULL;
 331     }
 332     assert(ov->list_mode == LM_IN_PROGRESS);
 333     return g_queue_peek_head(ov->repeated_opts);
 334 }
 335
 336
 337 static void
 338 processed(OptsVisitor *ov, const char *name)
 339 {
 340     if (ov->list_mode == LM_NONE) {
 341         g_hash_table_remove(ov->unprocessed_opts, name);
 342         return;
 343     }
 344     assert(ov->list_mode == LM_IN_PROGRESS);
 345     /* do nothing */
 346 }
 347
 348
 349 static bool
 350 opts_type_str(Visitor *v, const char *name, char **obj, Error **errp)
 351 {
 352     OptsVisitor *ov = to_ov(v);
 353     const QemuOpt *opt;
 354
 355     opt = lookup_scalar(ov, name, errp);
 356     if (!opt) {
 357         *obj = NULL;
 358         return false;
 359     }
 360     *obj = g_strdup(opt->str ? opt->str : "");
 361     /* Note that we consume a string even if this is called as part of
 362      * an enum visit that later fails because the string is not a
 363      * valid enum value; this is harmless because tracking what gets
 364      * consumed only matters to visit_end_struct() as the final error
 365      * check if there were no other failures during the visit.  */
 366     processed(ov, name);
 367     return true;
 368 }
 369
 370
 371 static bool
 372 opts_type_bool(Visitor *v, const char *name, bool *obj, Error **errp)
 373 {
 374     OptsVisitor *ov = to_ov(v);
 375     const QemuOpt *opt;
 376
 377     opt = lookup_scalar(ov, name, errp);
 378     if (!opt) {
 379         return false;
 380     }
 381     if (opt->str) {
 382         if (!qapi_bool_parse(opt->name, opt->str, obj, errp)) {
 383             return false;
 384         }
 385     } else {
 386         *obj = true;
 387     }
 388
 389     processed(ov, name);
 390     return true;
 391 }
 392
 393
 394 static bool
 395 opts_type_int64(Visitor *v, const char *name, int64_t *obj, Error **errp)
 396 {
 397     OptsVisitor *ov = to_ov(v);
 398     const QemuOpt *opt;
 399     const char *str;
 400     long long val;
 401     char *endptr;
 402
 403     if (ov->list_mode == LM_SIGNED_INTERVAL) {
 404         *obj = ov->range_next.s;
 405         return true;
 406     }
 407
 408     opt = lookup_scalar(ov, name, errp);
 409     if (!opt) {
 410         return false;
 411     }
 412     str = opt->str ? opt->str : "";
 413
 414     /* we've gotten past lookup_scalar() */
 415     assert(ov->list_mode == LM_NONE || ov->list_mode == LM_IN_PROGRESS);
 416
 417     errno = 0;
 418     val = strtoll(str, &endptr, 0);
 419     if (errno == 0 && endptr > str && INT64_MIN <= val && val <= INT64_MAX) {
 420         if (*endptr == '\0') {
 421             *obj = val;
 422             processed(ov, name);
 423             return true;
 424         }
 425         if (*endptr == '-' && ov->list_mode == LM_IN_PROGRESS) {
 426             long long val2;
 427
 428             str = endptr + 1;
 429             val2 = strtoll(str, &endptr, 0);
 430             if (errno == 0 && endptr > str && *endptr == '\0' &&
 431                 INT64_MIN <= val2 && val2 <= INT64_MAX && val <= val2 &&
 432                 (val > INT64_MAX - OPTS_VISITOR_RANGE_MAX ||
 433                  val2 < val + OPTS_VISITOR_RANGE_MAX)) {
 434                 ov->range_next.s = val;
 435                 ov->range_limit.s = val2;
 436                 ov->list_mode = LM_SIGNED_INTERVAL;
 437
 438                 /* as if entering on the top */
 439                 *obj = ov->range_next.s;
 440                 return true;
 441             }
 442         }
 443     }
 444     error_setg(errp, QERR_INVALID_PARAMETER_VALUE, opt->name,
 445                (ov->list_mode == LM_NONE) ? "an int64 value" :
 446                                             "an int64 value or range");
 447     return false;
 448 }
 449
 450
 451 static bool
 452 opts_type_uint64(Visitor *v, const char *name, uint64_t *obj, Error **errp)
 453 {
 454     OptsVisitor *ov = to_ov(v);
 455     const QemuOpt *opt;
 456     const char *str;
 457     uint64_t val;
 458     const char *endptr;
 459
 460     if (ov->list_mode == LM_UNSIGNED_INTERVAL) {
 461         *obj = ov->range_next.u;
 462         return true;
 463     }
 464
 465     opt = lookup_scalar(ov, name, errp);
 466     if (!opt) {
 467         return false;
 468     }
 469     str = opt->str;
 470
 471     /* we've gotten past lookup_scalar() */
 472     assert(ov->list_mode == LM_NONE || ov->list_mode == LM_IN_PROGRESS);
 473
 474     if (parse_uint(str, &endptr, 0, &val) == 0) {
 475         if (*endptr == '\0') {
 476             *obj = val;
 477             processed(ov, name);
 478             return true;
 479         }
 480         if (*endptr == '-' && ov->list_mode == LM_IN_PROGRESS) {
 481             uint64_t val2;
 482
 483             str = endptr + 1;
 484             if (parse_uint_full(str, 0, &val2) == 0 &&
 485                 val <= val2 &&
 486                 val2 - val < OPTS_VISITOR_RANGE_MAX) {
 487                 ov->range_next.u = val;
 488                 ov->range_limit.u = val2;
 489                 ov->list_mode = LM_UNSIGNED_INTERVAL;
 490
 491                 /* as if entering on the top */
 492                 *obj = ov->range_next.u;
 493                 return true;
 494             }
 495         }
 496     }
 497     error_setg(errp, QERR_INVALID_PARAMETER_VALUE, opt->name,
 498                (ov->list_mode == LM_NONE) ? "a uint64 value" :
 499                                             "a uint64 value or range");
 500     return false;
 501 }
 502
 503
 504 static bool
 505 opts_type_size(Visitor *v, const char *name, uint64_t *obj, Error **errp)
 506 {
 507     OptsVisitor *ov = to_ov(v);
 508     const QemuOpt *opt;
 509     int err;
 510
 511     opt = lookup_scalar(ov, name, errp);
 512     if (!opt) {
 513         return false;
 514     }
 515
 516     err = qemu_strtosz(opt->str ? opt->str : "", NULL, obj);
 517     if (err < 0) {
 518         error_setg(errp, QERR_INVALID_PARAMETER_VALUE, opt->name,
 519                    "a size value");
 520         return false;
 521     }
 522
 523     processed(ov, name);
 524     return true;
 525 }
 526
 527
 528 static void
 529 opts_optional(Visitor *v, const char *name, bool *present)
 530 {
 531     OptsVisitor *ov = to_ov(v);
 532
 533     /* we only support a single mandatory scalar field in a list node */
 534     assert(ov->list_mode == LM_NONE);
 535     *present = (lookup_distinct(ov, name, NULL) != NULL);
 536 }
 537
 538
 539 static void
 540 opts_free(Visitor *v)
 541 {
 542     OptsVisitor *ov = to_ov(v);
 543
 544     if (ov->unprocessed_opts != NULL) {
 545         g_hash_table_destroy(ov->unprocessed_opts);
 546     }
 547     g_free(ov->fake_id_opt);
 548     g_free(ov);
 549 }
 550
 551
 552 Visitor *
 553 opts_visitor_new(const QemuOpts *opts)
 554 {
 555     OptsVisitor *ov;
 556
 557     assert(opts);
 558     ov = g_malloc0(sizeof *ov);
 559
 560     ov->visitor.type = VISITOR_INPUT;
 561
 562     ov->visitor.start_struct = &opts_start_struct;
 563     ov->visitor.check_struct = &opts_check_struct;
 564     ov->visitor.end_struct   = &opts_end_struct;
 565
 566     ov->visitor.start_list = &opts_start_list;
 567     ov->visitor.next_list  = &opts_next_list;
 568     ov->visitor.check_list = &opts_check_list;
 569     ov->visitor.end_list   = &opts_end_list;
 570
 571     ov->visitor.type_int64  = &opts_type_int64;
 572     ov->visitor.type_uint64 = &opts_type_uint64;
 573     ov->visitor.type_size   = &opts_type_size;
 574     ov->visitor.type_bool   = &opts_type_bool;
 575     ov->visitor.type_str    = &opts_type_str;
 576
 577     /* type_number() is not filled in, but this is not the first visitor to
 578      * skip some mandatory methods... */
 579
 580     ov->visitor.optional = &opts_optional;
 581     ov->visitor.free = opts_free;
 582
 583     ov->opts_root = opts;
 584
 585     return &ov->visitor;
 586 }