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 void
 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;
 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 }
 167
 168
 169 static void
 170 opts_check_struct(Visitor *v, Error **errp)
 171 {
 172     OptsVisitor *ov = to_ov(v);
 173     GHashTableIter iter;
 174     GQueue *any;
 175
 176     if (ov->depth > 1) {
 177         return;
 178     }
 179
 180     /* we should have processed all (distinct) QemuOpt instances */
 181     g_hash_table_iter_init(&iter, ov->unprocessed_opts);
 182     if (g_hash_table_iter_next(&iter, NULL, (void **)&any)) {
 183         const QemuOpt *first;
 184
 185         first = g_queue_peek_head(any);
 186         error_setg(errp, QERR_INVALID_PARAMETER, first->name);
 187     }
 188 }
 189
 190
 191 static void
 192 opts_end_struct(Visitor *v, void **obj)
 193 {
 194     OptsVisitor *ov = to_ov(v);
 195
 196     if (--ov->depth > 0) {
 197         return;
 198     }
 199
 200     g_hash_table_destroy(ov->unprocessed_opts);
 201     ov->unprocessed_opts = NULL;
 202     if (ov->fake_id_opt) {
 203         g_free(ov->fake_id_opt->name);
 204         g_free(ov->fake_id_opt->str);
 205         g_free(ov->fake_id_opt);
 206     }
 207     ov->fake_id_opt = NULL;
 208 }
 209
 210
 211 static GQueue *
 212 lookup_distinct(const OptsVisitor *ov, const char *name, Error **errp)
 213 {
 214     GQueue *list;
 215
 216     list = g_hash_table_lookup(ov->unprocessed_opts, name);
 217     if (!list) {
 218         error_setg(errp, QERR_MISSING_PARAMETER, name);
 219     }
 220     return list;
 221 }
 222
 223
 224 static void
 225 opts_start_list(Visitor *v, const char *name, GenericList **list, size_t size,
 226                 Error **errp)
 227 {
 228     OptsVisitor *ov = to_ov(v);
 229
 230     /* we can't traverse a list in a list */
 231     assert(ov->list_mode == LM_NONE);
 232     /* we don't support visits without a list */
 233     assert(list);
 234     ov->repeated_opts = lookup_distinct(ov, name, errp);
 235     if (ov->repeated_opts) {
 236         ov->list_mode = LM_IN_PROGRESS;
 237         *list = g_malloc0(size);
 238     } else {
 239         *list = NULL;
 240     }
 241 }
 242
 243
 244 static GenericList *
 245 opts_next_list(Visitor *v, GenericList *tail, size_t size)
 246 {
 247     OptsVisitor *ov = to_ov(v);
 248
 249     switch (ov->list_mode) {
 250     case LM_TRAVERSED:
 251         return NULL;
 252     case LM_SIGNED_INTERVAL:
 253     case LM_UNSIGNED_INTERVAL:
 254         if (ov->list_mode == LM_SIGNED_INTERVAL) {
 255             if (ov->range_next.s < ov->range_limit.s) {
 256                 ++ov->range_next.s;
 257                 break;
 258             }
 259         } else if (ov->range_next.u < ov->range_limit.u) {
 260             ++ov->range_next.u;
 261             break;
 262         }
 263         ov->list_mode = LM_IN_PROGRESS;
 264         /* range has been completed, fall through in order to pop option */
 265
 266     case LM_IN_PROGRESS: {
 267         const QemuOpt *opt;
 268
 269         opt = g_queue_pop_head(ov->repeated_opts);
 270         if (g_queue_is_empty(ov->repeated_opts)) {
 271             g_hash_table_remove(ov->unprocessed_opts, opt->name);
 272             ov->repeated_opts = NULL;
 273             ov->list_mode = LM_TRAVERSED;
 274             return NULL;
 275         }
 276         break;
 277     }
 278
 279     default:
 280         abort();
 281     }
 282
 283     tail->next = g_malloc0(size);
 284     return tail->next;
 285 }
 286
 287
 288 static void
 289 opts_check_list(Visitor *v, Error **errp)
 290 {
 291     /*
 292      * Unvisited list elements will be reported later when checking
 293      * whether unvisited struct members remain.
 294      */
 295 }
 296
 297
 298 static void
 299 opts_end_list(Visitor *v, void **obj)
 300 {
 301     OptsVisitor *ov = to_ov(v);
 302
 303     assert(ov->list_mode == LM_IN_PROGRESS ||
 304            ov->list_mode == LM_SIGNED_INTERVAL ||
 305            ov->list_mode == LM_UNSIGNED_INTERVAL ||
 306            ov->list_mode == LM_TRAVERSED);
 307     ov->repeated_opts = NULL;
 308     ov->list_mode = LM_NONE;
 309 }
 310
 311
 312 static const QemuOpt *
 313 lookup_scalar(const OptsVisitor *ov, const char *name, Error **errp)
 314 {
 315     if (ov->list_mode == LM_NONE) {
 316         GQueue *list;
 317
 318         /* the last occurrence of any QemuOpt takes effect when queried by name
 319          */
 320         list = lookup_distinct(ov, name, errp);
 321         return list ? g_queue_peek_tail(list) : NULL;
 322     }
 323     if (ov->list_mode == LM_TRAVERSED) {
 324         error_setg(errp, "Fewer list elements than expected");
 325         return NULL;
 326     }
 327     assert(ov->list_mode == LM_IN_PROGRESS);
 328     return g_queue_peek_head(ov->repeated_opts);
 329 }
 330
 331
 332 static void
 333 processed(OptsVisitor *ov, const char *name)
 334 {
 335     if (ov->list_mode == LM_NONE) {
 336         g_hash_table_remove(ov->unprocessed_opts, name);
 337         return;
 338     }
 339     assert(ov->list_mode == LM_IN_PROGRESS);
 340     /* do nothing */
 341 }
 342
 343
 344 static void
 345 opts_type_str(Visitor *v, const char *name, char **obj, Error **errp)
 346 {
 347     OptsVisitor *ov = to_ov(v);
 348     const QemuOpt *opt;
 349
 350     opt = lookup_scalar(ov, name, errp);
 351     if (!opt) {
 352         *obj = NULL;
 353         return;
 354     }
 355     *obj = g_strdup(opt->str ? opt->str : "");
 356     /* Note that we consume a string even if this is called as part of
 357      * an enum visit that later fails because the string is not a
 358      * valid enum value; this is harmless because tracking what gets
 359      * consumed only matters to visit_end_struct() as the final error
 360      * check if there were no other failures during the visit.  */
 361     processed(ov, name);
 362 }
 363
 364
 365 /* mimics qemu-option.c::parse_option_bool() */
 366 static void
 367 opts_type_bool(Visitor *v, const char *name, bool *obj, Error **errp)
 368 {
 369     OptsVisitor *ov = to_ov(v);
 370     const QemuOpt *opt;
 371
 372     opt = lookup_scalar(ov, name, errp);
 373     if (!opt) {
 374         return;
 375     }
 376
 377     if (opt->str) {
 378         if (strcmp(opt->str, "on") == 0 ||
 379             strcmp(opt->str, "yes") == 0 ||
 380             strcmp(opt->str, "y") == 0) {
 381             *obj = true;
 382         } else if (strcmp(opt->str, "off") == 0 ||
 383             strcmp(opt->str, "no") == 0 ||
 384             strcmp(opt->str, "n") == 0) {
 385             *obj = false;
 386         } else {
 387             error_setg(errp, QERR_INVALID_PARAMETER_VALUE, opt->name,
 388                        "on|yes|y|off|no|n");
 389             return;
 390         }
 391     } else {
 392         *obj = true;
 393     }
 394
 395     processed(ov, name);
 396 }
 397
 398
 399 static void
 400 opts_type_int64(Visitor *v, const char *name, int64_t *obj, Error **errp)
 401 {
 402     OptsVisitor *ov = to_ov(v);
 403     const QemuOpt *opt;
 404     const char *str;
 405     long long val;
 406     char *endptr;
 407
 408     if (ov->list_mode == LM_SIGNED_INTERVAL) {
 409         *obj = ov->range_next.s;
 410         return;
 411     }
 412
 413     opt = lookup_scalar(ov, name, errp);
 414     if (!opt) {
 415         return;
 416     }
 417     str = opt->str ? opt->str : "";
 418
 419     /* we've gotten past lookup_scalar() */
 420     assert(ov->list_mode == LM_NONE || ov->list_mode == LM_IN_PROGRESS);
 421
 422     errno = 0;
 423     val = strtoll(str, &endptr, 0);
 424     if (errno == 0 && endptr > str && INT64_MIN <= val && val <= INT64_MAX) {
 425         if (*endptr == '\0') {
 426             *obj = val;
 427             processed(ov, name);
 428             return;
 429         }
 430         if (*endptr == '-' && ov->list_mode == LM_IN_PROGRESS) {
 431             long long val2;
 432
 433             str = endptr + 1;
 434             val2 = strtoll(str, &endptr, 0);
 435             if (errno == 0 && endptr > str && *endptr == '\0' &&
 436                 INT64_MIN <= val2 && val2 <= INT64_MAX && val <= val2 &&
 437                 (val > INT64_MAX - OPTS_VISITOR_RANGE_MAX ||
 438                  val2 < val + OPTS_VISITOR_RANGE_MAX)) {
 439                 ov->range_next.s = val;
 440                 ov->range_limit.s = val2;
 441                 ov->list_mode = LM_SIGNED_INTERVAL;
 442
 443                 /* as if entering on the top */
 444                 *obj = ov->range_next.s;
 445                 return;
 446             }
 447         }
 448     }
 449     error_setg(errp, QERR_INVALID_PARAMETER_VALUE, opt->name,
 450                (ov->list_mode == LM_NONE) ? "an int64 value" :
 451                                             "an int64 value or range");
 452 }
 453
 454
 455 static void
 456 opts_type_uint64(Visitor *v, const char *name, uint64_t *obj, Error **errp)
 457 {
 458     OptsVisitor *ov = to_ov(v);
 459     const QemuOpt *opt;
 460     const char *str;
 461     unsigned long long val;
 462     char *endptr;
 463
 464     if (ov->list_mode == LM_UNSIGNED_INTERVAL) {
 465         *obj = ov->range_next.u;
 466         return;
 467     }
 468
 469     opt = lookup_scalar(ov, name, errp);
 470     if (!opt) {
 471         return;
 472     }
 473     str = opt->str;
 474
 475     /* we've gotten past lookup_scalar() */
 476     assert(ov->list_mode == LM_NONE || ov->list_mode == LM_IN_PROGRESS);
 477
 478     if (parse_uint(str, &val, &endptr, 0) == 0 && val <= UINT64_MAX) {
 479         if (*endptr == '\0') {
 480             *obj = val;
 481             processed(ov, name);
 482             return;
 483         }
 484         if (*endptr == '-' && ov->list_mode == LM_IN_PROGRESS) {
 485             unsigned long long val2;
 486
 487             str = endptr + 1;
 488             if (parse_uint_full(str, &val2, 0) == 0 &&
 489                 val2 <= UINT64_MAX && val <= val2 &&
 490                 val2 - val < OPTS_VISITOR_RANGE_MAX) {
 491                 ov->range_next.u = val;
 492                 ov->range_limit.u = val2;
 493                 ov->list_mode = LM_UNSIGNED_INTERVAL;
 494
 495                 /* as if entering on the top */
 496                 *obj = ov->range_next.u;
 497                 return;
 498             }
 499         }
 500     }
 501     error_setg(errp, QERR_INVALID_PARAMETER_VALUE, opt->name,
 502                (ov->list_mode == LM_NONE) ? "a uint64 value" :
 503                                             "a uint64 value or range");
 504 }
 505
 506
 507 static void
 508 opts_type_size(Visitor *v, const char *name, uint64_t *obj, Error **errp)
 509 {
 510     OptsVisitor *ov = to_ov(v);
 511     const QemuOpt *opt;
 512     int err;
 513
 514     opt = lookup_scalar(ov, name, errp);
 515     if (!opt) {
 516         return;
 517     }
 518
 519     err = qemu_strtosz(opt->str ? opt->str : "", NULL, obj);
 520     if (err < 0) {
 521         error_setg(errp, QERR_INVALID_PARAMETER_VALUE, opt->name,
 522                    "a size value");
 523         return;
 524     }
 525
 526     processed(ov, name);
 527 }
 528
 529
 530 static void
 531 opts_optional(Visitor *v, const char *name, bool *present)
 532 {
 533     OptsVisitor *ov = to_ov(v);
 534
 535     /* we only support a single mandatory scalar field in a list node */
 536     assert(ov->list_mode == LM_NONE);
 537     *present = (lookup_distinct(ov, name, NULL) != NULL);
 538 }
 539
 540
 541 static void
 542 opts_free(Visitor *v)
 543 {
 544     OptsVisitor *ov = to_ov(v);
 545
 546     if (ov->unprocessed_opts != NULL) {
 547         g_hash_table_destroy(ov->unprocessed_opts);
 548     }
 549     g_free(ov->fake_id_opt);
 550     g_free(ov);
 551 }
 552
 553
 554 Visitor *
 555 opts_visitor_new(const QemuOpts *opts)
 556 {
 557     OptsVisitor *ov;
 558
 559     assert(opts);
 560     ov = g_malloc0(sizeof *ov);
 561
 562     ov->visitor.type = VISITOR_INPUT;
 563
 564     ov->visitor.start_struct = &opts_start_struct;
 565     ov->visitor.check_struct = &opts_check_struct;
 566     ov->visitor.end_struct   = &opts_end_struct;
 567
 568     ov->visitor.start_list = &opts_start_list;
 569     ov->visitor.next_list  = &opts_next_list;
 570     ov->visitor.check_list = &opts_check_list;
 571     ov->visitor.end_list   = &opts_end_list;
 572
 573     ov->visitor.type_int64  = &opts_type_int64;
 574     ov->visitor.type_uint64 = &opts_type_uint64;
 575     ov->visitor.type_size   = &opts_type_size;
 576     ov->visitor.type_bool   = &opts_type_bool;
 577     ov->visitor.type_str    = &opts_type_str;
 578
 579     /* type_number() is not filled in, but this is not the first visitor to
 580      * skip some mandatory methods... */
 581
 582     ov->visitor.optional = &opts_optional;
 583     ov->visitor.free = opts_free;
 584
 585     ov->opts_root = opts;
 586
 587     return &ov->visitor;
 588 }