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,      /* opts_next_list() ready to be called.
  28                           *
  29                           * Generating the next list link will consume the most
  30                           * recently parsed QemuOpt instance of the repeated
  31                           * option.
  32                           *
  33                           * Parsing a value into the list link will examine the
  34                           * next QemuOpt instance of the repeated option, and
  35                           * possibly enter LM_SIGNED_INTERVAL or
  36                           * LM_UNSIGNED_INTERVAL.
  37                           */
  38
  39     LM_SIGNED_INTERVAL,  /* opts_next_list() has been called.
  40                           *
  41                           * Generating the next list link will consume the most
  42                           * recently stored element from the signed interval,
  43                           * parsed from the most recent QemuOpt instance of the
  44                           * repeated option. This may consume QemuOpt itself
  45                           * and return to LM_IN_PROGRESS.
  46                           *
  47                           * Parsing a value into the list link will store the
  48                           * next element of the signed interval.
  49                           */
  50
  51     LM_UNSIGNED_INTERVAL /* Same as above, only for an unsigned interval. */
  52 };
  53
  54 typedef enum ListMode ListMode;
  55
  56 struct OptsVisitor
  57 {
  58     Visitor visitor;
  59
  60     /* Ownership remains with opts_visitor_new()'s caller. */
  61     const QemuOpts *opts_root;
  62
  63     unsigned depth;
  64
  65     /* Non-null iff depth is positive. Each key is a QemuOpt name. Each value
  66      * is a non-empty GQueue, enumerating all QemuOpt occurrences with that
  67      * name. */
  68     GHashTable *unprocessed_opts;
  69
  70     /* The list currently being traversed with opts_start_list() /
  71      * opts_next_list(). The list must have a struct element type in the
  72      * schema, with a single mandatory scalar member. */
  73     ListMode list_mode;
  74     GQueue *repeated_opts;
  75
  76     /* When parsing a list of repeating options as integers, values of the form
  77      * "a-b", representing a closed interval, are allowed. Elements in the
  78      * range are generated individually.
  79      */
  80     union {
  81         int64_t s;
  82         uint64_t u;
  83     } range_next, range_limit;
  84
  85     /* If "opts_root->id" is set, reinstantiate it as a fake QemuOpt for
  86      * uniformity. Only its "name" and "str" fields are set. "fake_id_opt" does
  87      * not survive or escape the OptsVisitor object.
  88      */
  89     QemuOpt *fake_id_opt;
  90 };
  91
  92
  93 static OptsVisitor *to_ov(Visitor *v)
  94 {
  95     return container_of(v, OptsVisitor, visitor);
  96 }
  97
  98
  99 static void
 100 destroy_list(gpointer list)
 101 {
 102   g_queue_free(list);
 103 }
 104
 105
 106 static void
 107 opts_visitor_insert(GHashTable *unprocessed_opts, const QemuOpt *opt)
 108 {
 109     GQueue *list;
 110
 111     list = g_hash_table_lookup(unprocessed_opts, opt->name);
 112     if (list == NULL) {
 113         list = g_queue_new();
 114
 115         /* GHashTable will never try to free the keys -- we supply NULL as
 116          * "key_destroy_func" in opts_start_struct(). Thus cast away key
 117          * const-ness in order to suppress gcc's warning.
 118          */
 119         g_hash_table_insert(unprocessed_opts, (gpointer)opt->name, list);
 120     }
 121
 122     /* Similarly, destroy_list() doesn't call g_queue_free_full(). */
 123     g_queue_push_tail(list, (gpointer)opt);
 124 }
 125
 126
 127 static void
 128 opts_start_struct(Visitor *v, const char *name, void **obj,
 129                   size_t size, Error **errp)
 130 {
 131     OptsVisitor *ov = to_ov(v);
 132     const QemuOpt *opt;
 133
 134     if (obj) {
 135         *obj = g_malloc0(size);
 136     }
 137     if (ov->depth++ > 0) {
 138         return;
 139     }
 140
 141     ov->unprocessed_opts = g_hash_table_new_full(&g_str_hash, &g_str_equal,
 142                                                  NULL, &destroy_list);
 143     QTAILQ_FOREACH(opt, &ov->opts_root->head, next) {
 144         /* ensured by qemu-option.c::opts_do_parse() */
 145         assert(strcmp(opt->name, "id") != 0);
 146
 147         opts_visitor_insert(ov->unprocessed_opts, opt);
 148     }
 149
 150     if (ov->opts_root->id != NULL) {
 151         ov->fake_id_opt = g_malloc0(sizeof *ov->fake_id_opt);
 152
 153         ov->fake_id_opt->name = g_strdup("id");
 154         ov->fake_id_opt->str = g_strdup(ov->opts_root->id);
 155         opts_visitor_insert(ov->unprocessed_opts, ov->fake_id_opt);
 156     }
 157 }
 158
 159
 160 static void
 161 opts_check_struct(Visitor *v, Error **errp)
 162 {
 163     OptsVisitor *ov = to_ov(v);
 164     GHashTableIter iter;
 165     GQueue *any;
 166
 167     if (ov->depth > 0) {
 168         return;
 169     }
 170
 171     /* we should have processed all (distinct) QemuOpt instances */
 172     g_hash_table_iter_init(&iter, ov->unprocessed_opts);
 173     if (g_hash_table_iter_next(&iter, NULL, (void **)&any)) {
 174         const QemuOpt *first;
 175
 176         first = g_queue_peek_head(any);
 177         error_setg(errp, QERR_INVALID_PARAMETER, first->name);
 178     }
 179 }
 180
 181
 182 static void
 183 opts_end_struct(Visitor *v, void **obj)
 184 {
 185     OptsVisitor *ov = to_ov(v);
 186
 187     if (--ov->depth > 0) {
 188         return;
 189     }
 190
 191     g_hash_table_destroy(ov->unprocessed_opts);
 192     ov->unprocessed_opts = NULL;
 193     if (ov->fake_id_opt) {
 194         g_free(ov->fake_id_opt->name);
 195         g_free(ov->fake_id_opt->str);
 196         g_free(ov->fake_id_opt);
 197     }
 198     ov->fake_id_opt = NULL;
 199 }
 200
 201
 202 static GQueue *
 203 lookup_distinct(const OptsVisitor *ov, const char *name, Error **errp)
 204 {
 205     GQueue *list;
 206
 207     list = g_hash_table_lookup(ov->unprocessed_opts, name);
 208     if (!list) {
 209         error_setg(errp, QERR_MISSING_PARAMETER, name);
 210     }
 211     return list;
 212 }
 213
 214
 215 static void
 216 opts_start_list(Visitor *v, const char *name, GenericList **list, size_t size,
 217                 Error **errp)
 218 {
 219     OptsVisitor *ov = to_ov(v);
 220
 221     /* we can't traverse a list in a list */
 222     assert(ov->list_mode == LM_NONE);
 223     /* we don't support visits without a list */
 224     assert(list);
 225     ov->repeated_opts = lookup_distinct(ov, name, errp);
 226     if (ov->repeated_opts) {
 227         ov->list_mode = LM_IN_PROGRESS;
 228         *list = g_malloc0(size);
 229     } else {
 230         *list = NULL;
 231     }
 232 }
 233
 234
 235 static GenericList *
 236 opts_next_list(Visitor *v, GenericList *tail, size_t size)
 237 {
 238     OptsVisitor *ov = to_ov(v);
 239
 240     switch (ov->list_mode) {
 241     case LM_SIGNED_INTERVAL:
 242     case LM_UNSIGNED_INTERVAL:
 243         if (ov->list_mode == LM_SIGNED_INTERVAL) {
 244             if (ov->range_next.s < ov->range_limit.s) {
 245                 ++ov->range_next.s;
 246                 break;
 247             }
 248         } else if (ov->range_next.u < ov->range_limit.u) {
 249             ++ov->range_next.u;
 250             break;
 251         }
 252         ov->list_mode = LM_IN_PROGRESS;
 253         /* range has been completed, fall through in order to pop option */
 254
 255     case LM_IN_PROGRESS: {
 256         const QemuOpt *opt;
 257
 258         opt = g_queue_pop_head(ov->repeated_opts);
 259         if (g_queue_is_empty(ov->repeated_opts)) {
 260             g_hash_table_remove(ov->unprocessed_opts, opt->name);
 261             return NULL;
 262         }
 263         break;
 264     }
 265
 266     default:
 267         abort();
 268     }
 269
 270     tail->next = g_malloc0(size);
 271     return tail->next;
 272 }
 273
 274
 275 static void
 276 opts_end_list(Visitor *v, void **obj)
 277 {
 278     OptsVisitor *ov = to_ov(v);
 279
 280     assert(ov->list_mode == LM_IN_PROGRESS ||
 281            ov->list_mode == LM_SIGNED_INTERVAL ||
 282            ov->list_mode == LM_UNSIGNED_INTERVAL);
 283     ov->repeated_opts = NULL;
 284     ov->list_mode = LM_NONE;
 285 }
 286
 287
 288 static const QemuOpt *
 289 lookup_scalar(const OptsVisitor *ov, const char *name, Error **errp)
 290 {
 291     if (ov->list_mode == LM_NONE) {
 292         GQueue *list;
 293
 294         /* the last occurrence of any QemuOpt takes effect when queried by name
 295          */
 296         list = lookup_distinct(ov, name, errp);
 297         return list ? g_queue_peek_tail(list) : NULL;
 298     }
 299     assert(ov->list_mode == LM_IN_PROGRESS);
 300     return g_queue_peek_head(ov->repeated_opts);
 301 }
 302
 303
 304 static void
 305 processed(OptsVisitor *ov, const char *name)
 306 {
 307     if (ov->list_mode == LM_NONE) {
 308         g_hash_table_remove(ov->unprocessed_opts, name);
 309         return;
 310     }
 311     assert(ov->list_mode == LM_IN_PROGRESS);
 312     /* do nothing */
 313 }
 314
 315
 316 static void
 317 opts_type_str(Visitor *v, const char *name, char **obj, Error **errp)
 318 {
 319     OptsVisitor *ov = to_ov(v);
 320     const QemuOpt *opt;
 321
 322     opt = lookup_scalar(ov, name, errp);
 323     if (!opt) {
 324         *obj = NULL;
 325         return;
 326     }
 327     *obj = g_strdup(opt->str ? opt->str : "");
 328     /* Note that we consume a string even if this is called as part of
 329      * an enum visit that later fails because the string is not a
 330      * valid enum value; this is harmless because tracking what gets
 331      * consumed only matters to visit_end_struct() as the final error
 332      * check if there were no other failures during the visit.  */
 333     processed(ov, name);
 334 }
 335
 336
 337 /* mimics qemu-option.c::parse_option_bool() */
 338 static void
 339 opts_type_bool(Visitor *v, const char *name, bool *obj, Error **errp)
 340 {
 341     OptsVisitor *ov = to_ov(v);
 342     const QemuOpt *opt;
 343
 344     opt = lookup_scalar(ov, name, errp);
 345     if (!opt) {
 346         return;
 347     }
 348
 349     if (opt->str) {
 350         if (strcmp(opt->str, "on") == 0 ||
 351             strcmp(opt->str, "yes") == 0 ||
 352             strcmp(opt->str, "y") == 0) {
 353             *obj = true;
 354         } else if (strcmp(opt->str, "off") == 0 ||
 355             strcmp(opt->str, "no") == 0 ||
 356             strcmp(opt->str, "n") == 0) {
 357             *obj = false;
 358         } else {
 359             error_setg(errp, QERR_INVALID_PARAMETER_VALUE, opt->name,
 360                        "on|yes|y|off|no|n");
 361             return;
 362         }
 363     } else {
 364         *obj = true;
 365     }
 366
 367     processed(ov, name);
 368 }
 369
 370
 371 static void
 372 opts_type_int64(Visitor *v, const char *name, int64_t *obj, Error **errp)
 373 {
 374     OptsVisitor *ov = to_ov(v);
 375     const QemuOpt *opt;
 376     const char *str;
 377     long long val;
 378     char *endptr;
 379
 380     if (ov->list_mode == LM_SIGNED_INTERVAL) {
 381         *obj = ov->range_next.s;
 382         return;
 383     }
 384
 385     opt = lookup_scalar(ov, name, errp);
 386     if (!opt) {
 387         return;
 388     }
 389     str = opt->str ? opt->str : "";
 390
 391     /* we've gotten past lookup_scalar() */
 392     assert(ov->list_mode == LM_NONE || ov->list_mode == LM_IN_PROGRESS);
 393
 394     errno = 0;
 395     val = strtoll(str, &endptr, 0);
 396     if (errno == 0 && endptr > str && INT64_MIN <= val && val <= INT64_MAX) {
 397         if (*endptr == '\0') {
 398             *obj = val;
 399             processed(ov, name);
 400             return;
 401         }
 402         if (*endptr == '-' && ov->list_mode == LM_IN_PROGRESS) {
 403             long long val2;
 404
 405             str = endptr + 1;
 406             val2 = strtoll(str, &endptr, 0);
 407             if (errno == 0 && endptr > str && *endptr == '\0' &&
 408                 INT64_MIN <= val2 && val2 <= INT64_MAX && val <= val2 &&
 409                 (val > INT64_MAX - OPTS_VISITOR_RANGE_MAX ||
 410                  val2 < val + OPTS_VISITOR_RANGE_MAX)) {
 411                 ov->range_next.s = val;
 412                 ov->range_limit.s = val2;
 413                 ov->list_mode = LM_SIGNED_INTERVAL;
 414
 415                 /* as if entering on the top */
 416                 *obj = ov->range_next.s;
 417                 return;
 418             }
 419         }
 420     }
 421     error_setg(errp, QERR_INVALID_PARAMETER_VALUE, opt->name,
 422                (ov->list_mode == LM_NONE) ? "an int64 value" :
 423                                             "an int64 value or range");
 424 }
 425
 426
 427 static void
 428 opts_type_uint64(Visitor *v, const char *name, uint64_t *obj, Error **errp)
 429 {
 430     OptsVisitor *ov = to_ov(v);
 431     const QemuOpt *opt;
 432     const char *str;
 433     unsigned long long val;
 434     char *endptr;
 435
 436     if (ov->list_mode == LM_UNSIGNED_INTERVAL) {
 437         *obj = ov->range_next.u;
 438         return;
 439     }
 440
 441     opt = lookup_scalar(ov, name, errp);
 442     if (!opt) {
 443         return;
 444     }
 445     str = opt->str;
 446
 447     /* we've gotten past lookup_scalar() */
 448     assert(ov->list_mode == LM_NONE || ov->list_mode == LM_IN_PROGRESS);
 449
 450     if (parse_uint(str, &val, &endptr, 0) == 0 && val <= UINT64_MAX) {
 451         if (*endptr == '\0') {
 452             *obj = val;
 453             processed(ov, name);
 454             return;
 455         }
 456         if (*endptr == '-' && ov->list_mode == LM_IN_PROGRESS) {
 457             unsigned long long val2;
 458
 459             str = endptr + 1;
 460             if (parse_uint_full(str, &val2, 0) == 0 &&
 461                 val2 <= UINT64_MAX && val <= val2 &&
 462                 val2 - val < OPTS_VISITOR_RANGE_MAX) {
 463                 ov->range_next.u = val;
 464                 ov->range_limit.u = val2;
 465                 ov->list_mode = LM_UNSIGNED_INTERVAL;
 466
 467                 /* as if entering on the top */
 468                 *obj = ov->range_next.u;
 469                 return;
 470             }
 471         }
 472     }
 473     error_setg(errp, QERR_INVALID_PARAMETER_VALUE, opt->name,
 474                (ov->list_mode == LM_NONE) ? "a uint64 value" :
 475                                             "a uint64 value or range");
 476 }
 477
 478
 479 static void
 480 opts_type_size(Visitor *v, const char *name, uint64_t *obj, Error **errp)
 481 {
 482     OptsVisitor *ov = to_ov(v);
 483     const QemuOpt *opt;
 484     int64_t val;
 485     char *endptr;
 486
 487     opt = lookup_scalar(ov, name, errp);
 488     if (!opt) {
 489         return;
 490     }
 491
 492     val = qemu_strtosz_suffix(opt->str ? opt->str : "", &endptr,
 493                          QEMU_STRTOSZ_DEFSUFFIX_B);
 494     if (val < 0 || *endptr) {
 495         error_setg(errp, QERR_INVALID_PARAMETER_VALUE, opt->name,
 496                    "a size value representible as a non-negative int64");
 497         return;
 498     }
 499
 500     *obj = val;
 501     processed(ov, name);
 502 }
 503
 504
 505 static void
 506 opts_optional(Visitor *v, const char *name, bool *present)
 507 {
 508     OptsVisitor *ov = to_ov(v);
 509
 510     /* we only support a single mandatory scalar field in a list node */
 511     assert(ov->list_mode == LM_NONE);
 512     *present = (lookup_distinct(ov, name, NULL) != NULL);
 513 }
 514
 515
 516 static void
 517 opts_free(Visitor *v)
 518 {
 519     OptsVisitor *ov = to_ov(v);
 520
 521     if (ov->unprocessed_opts != NULL) {
 522         g_hash_table_destroy(ov->unprocessed_opts);
 523     }
 524     g_free(ov->fake_id_opt);
 525     g_free(ov);
 526 }
 527
 528
 529 Visitor *
 530 opts_visitor_new(const QemuOpts *opts)
 531 {
 532     OptsVisitor *ov;
 533
 534     ov = g_malloc0(sizeof *ov);
 535
 536     ov->visitor.type = VISITOR_INPUT;
 537
 538     ov->visitor.start_struct = &opts_start_struct;
 539     ov->visitor.check_struct = &opts_check_struct;
 540     ov->visitor.end_struct   = &opts_end_struct;
 541
 542     ov->visitor.start_list = &opts_start_list;
 543     ov->visitor.next_list  = &opts_next_list;
 544     ov->visitor.end_list   = &opts_end_list;
 545
 546     ov->visitor.type_int64  = &opts_type_int64;
 547     ov->visitor.type_uint64 = &opts_type_uint64;
 548     ov->visitor.type_size   = &opts_type_size;
 549     ov->visitor.type_bool   = &opts_type_bool;
 550     ov->visitor.type_str    = &opts_type_str;
 551
 552     /* type_number() is not filled in, but this is not the first visitor to
 553      * skip some mandatory methods... */
 554
 555     ov->visitor.optional = &opts_optional;
 556     ov->visitor.free = opts_free;
 557
 558     ov->opts_root = opts;
 559
 560     return &ov->visitor;
 561 }