qapi/string-input-visitor.c

   1 /*
   2  * String parsing visitor
   3  *
   4  * Copyright Red Hat, Inc. 2012-2016
   5  *
   6  * Author: Paolo Bonzini <pbonzini@redhat.com>
   7  *         David Hildenbrand <david@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
  13 #include "qemu/osdep.h"
  14 #include "qapi/error.h"
  15 #include "qapi/string-input-visitor.h"
  16 #include "qapi/visitor-impl.h"
  17 #include "qapi/qmp/qerror.h"
  18 #include "qapi/qmp/qnull.h"
  19 #include "qemu/option.h"
  20 #include "qemu/cutils.h"
  21
  22 typedef enum ListMode {
  23     /* no list parsing active / no list expected */
  24     LM_NONE,
  25     /* we have an unparsed string remaining */
  26     LM_UNPARSED,
  27     /* we have an unfinished int64 range */
  28     LM_INT64_RANGE,
  29     /* we have an unfinished uint64 range */
  30     LM_UINT64_RANGE,
  31     /* we have parsed the string completely and no range is remaining */
  32     LM_END,
  33 } ListMode;
  34
  35 /* protect against DOS attacks, limit the amount of elements per range */
  36 #define RANGE_MAX_ELEMENTS 65536
  37
  38 typedef union RangeElement {
  39     int64_t i64;
  40     uint64_t u64;
  41 } RangeElement;
  42
  43 struct StringInputVisitor
  44 {
  45     Visitor visitor;
  46
  47     /* List parsing state */
  48     ListMode lm;
  49     RangeElement rangeNext;
  50     RangeElement rangeEnd;
  51     const char *unparsed_string;
  52     void *list;
  53
  54     /* The original string to parse */
  55     const char *string;
  56 };
  57
  58 static StringInputVisitor *to_siv(Visitor *v)
  59 {
  60     return container_of(v, StringInputVisitor, visitor);
  61 }
  62
  63 static bool start_list(Visitor *v, const char *name, GenericList **list,
  64                        size_t size, Error **errp)
  65 {
  66     StringInputVisitor *siv = to_siv(v);
  67
  68     assert(siv->lm == LM_NONE);
  69     siv->list = list;
  70     siv->unparsed_string = siv->string;
  71
  72     if (!siv->string[0]) {
  73         if (list) {
  74             *list = NULL;
  75         }
  76         siv->lm = LM_END;
  77     } else {
  78         if (list) {
  79             *list = g_malloc0(size);
  80         }
  81         siv->lm = LM_UNPARSED;
  82     }
  83     return true;
  84 }
  85
  86 static GenericList *next_list(Visitor *v, GenericList *tail, size_t size)
  87 {
  88     StringInputVisitor *siv = to_siv(v);
  89
  90     switch (siv->lm) {
  91     case LM_END:
  92         return NULL;
  93     case LM_INT64_RANGE:
  94     case LM_UINT64_RANGE:
  95     case LM_UNPARSED:
  96         /* we have an unparsed string or something left in a range */
  97         break;
  98     default:
  99         abort();
 100     }
 101
 102     tail->next = g_malloc0(size);
 103     return tail->next;
 104 }
 105
 106 static bool check_list(Visitor *v, Error **errp)
 107 {
 108     const StringInputVisitor *siv = to_siv(v);
 109
 110     switch (siv->lm) {
 111     case LM_INT64_RANGE:
 112     case LM_UINT64_RANGE:
 113     case LM_UNPARSED:
 114         error_setg(errp, "Fewer list elements expected");
 115         return false;
 116     case LM_END:
 117         return true;
 118     default:
 119         abort();
 120     }
 121 }
 122
 123 static void end_list(Visitor *v, void **obj)
 124 {
 125     StringInputVisitor *siv = to_siv(v);
 126
 127     assert(siv->lm != LM_NONE);
 128     assert(siv->list == obj);
 129     siv->list = NULL;
 130     siv->unparsed_string = NULL;
 131     siv->lm = LM_NONE;
 132 }
 133
 134 static int try_parse_int64_list_entry(StringInputVisitor *siv, int64_t *obj)
 135 {
 136     const char *endptr;
 137     int64_t start, end;
 138
 139     /* parse a simple int64 or range */
 140     if (qemu_strtoi64(siv->unparsed_string, &endptr, 0, &start)) {
 141         return -EINVAL;
 142     }
 143     end = start;
 144
 145     switch (endptr[0]) {
 146     case '\0':
 147         siv->unparsed_string = endptr;
 148         break;
 149     case ',':
 150         siv->unparsed_string = endptr + 1;
 151         break;
 152     case '-':
 153         /* parse the end of the range */
 154         if (qemu_strtoi64(endptr + 1, &endptr, 0, &end)) {
 155             return -EINVAL;
 156         }
 157         if (start > end || end - start >= RANGE_MAX_ELEMENTS) {
 158             return -EINVAL;
 159         }
 160         switch (endptr[0]) {
 161         case '\0':
 162             siv->unparsed_string = endptr;
 163             break;
 164         case ',':
 165             siv->unparsed_string = endptr + 1;
 166             break;
 167         default:
 168             return -EINVAL;
 169         }
 170         break;
 171     default:
 172         return -EINVAL;
 173     }
 174
 175     /* we have a proper range (with maybe only one element) */
 176     siv->lm = LM_INT64_RANGE;
 177     siv->rangeNext.i64 = start;
 178     siv->rangeEnd.i64 = end;
 179     return 0;
 180 }
 181
 182 static bool parse_type_int64(Visitor *v, const char *name, int64_t *obj,
 183                              Error **errp)
 184 {
 185     StringInputVisitor *siv = to_siv(v);
 186     int64_t val;
 187
 188     switch (siv->lm) {
 189     case LM_NONE:
 190         /* just parse a simple int64, bail out if not completely consumed */
 191         if (qemu_strtoi64(siv->string, NULL, 0, &val)) {
 192             error_setg(errp, QERR_INVALID_PARAMETER_VALUE,
 193                        name ? name : "null", "int64");
 194             return false;
 195         }
 196         *obj = val;
 197         return true;
 198     case LM_UNPARSED:
 199         if (try_parse_int64_list_entry(siv, obj)) {
 200             error_setg(errp, QERR_INVALID_PARAMETER_VALUE, name ? name : "null",
 201                        "list of int64 values or ranges");
 202             return false;
 203         }
 204         assert(siv->lm == LM_INT64_RANGE);
 205         /* fall through */
 206     case LM_INT64_RANGE:
 207         /* return the next element in the range */
 208         assert(siv->rangeNext.i64 <= siv->rangeEnd.i64);
 209         *obj = siv->rangeNext.i64++;
 210
 211         if (siv->rangeNext.i64 > siv->rangeEnd.i64 || *obj == INT64_MAX) {
 212             /* end of range, check if there is more to parse */
 213             siv->lm = siv->unparsed_string[0] ? LM_UNPARSED : LM_END;
 214         }
 215         return true;
 216     case LM_END:
 217         error_setg(errp, "Fewer list elements expected");
 218         return false;
 219     default:
 220         abort();
 221     }
 222 }
 223
 224 static int try_parse_uint64_list_entry(StringInputVisitor *siv, uint64_t *obj)
 225 {
 226     const char *endptr;
 227     uint64_t start, end;
 228
 229     /* parse a simple uint64 or range */
 230     if (qemu_strtou64(siv->unparsed_string, &endptr, 0, &start)) {
 231         return -EINVAL;
 232     }
 233     end = start;
 234
 235     switch (endptr[0]) {
 236     case '\0':
 237         siv->unparsed_string = endptr;
 238         break;
 239     case ',':
 240         siv->unparsed_string = endptr + 1;
 241         break;
 242     case '-':
 243         /* parse the end of the range */
 244         if (qemu_strtou64(endptr + 1, &endptr, 0, &end)) {
 245             return -EINVAL;
 246         }
 247         if (start > end || end - start >= RANGE_MAX_ELEMENTS) {
 248             return -EINVAL;
 249         }
 250         switch (endptr[0]) {
 251         case '\0':
 252             siv->unparsed_string = endptr;
 253             break;
 254         case ',':
 255             siv->unparsed_string = endptr + 1;
 256             break;
 257         default:
 258             return -EINVAL;
 259         }
 260         break;
 261     default:
 262         return -EINVAL;
 263     }
 264
 265     /* we have a proper range (with maybe only one element) */
 266     siv->lm = LM_UINT64_RANGE;
 267     siv->rangeNext.u64 = start;
 268     siv->rangeEnd.u64 = end;
 269     return 0;
 270 }
 271
 272 static bool parse_type_uint64(Visitor *v, const char *name, uint64_t *obj,
 273                               Error **errp)
 274 {
 275     StringInputVisitor *siv = to_siv(v);
 276     uint64_t val;
 277
 278     switch (siv->lm) {
 279     case LM_NONE:
 280         /* just parse a simple uint64, bail out if not completely consumed */
 281         if (qemu_strtou64(siv->string, NULL, 0, &val)) {
 282             error_setg(errp, QERR_INVALID_PARAMETER_VALUE, name ? name : "null",
 283                        "uint64");
 284             return false;
 285         }
 286         *obj = val;
 287         return true;
 288     case LM_UNPARSED:
 289         if (try_parse_uint64_list_entry(siv, obj)) {
 290             error_setg(errp, QERR_INVALID_PARAMETER_VALUE, name ? name : "null",
 291                        "list of uint64 values or ranges");
 292             return false;
 293         }
 294         assert(siv->lm == LM_UINT64_RANGE);
 295         /* fall through */
 296     case LM_UINT64_RANGE:
 297         /* return the next element in the range */
 298         assert(siv->rangeNext.u64 <= siv->rangeEnd.u64);
 299         *obj = siv->rangeNext.u64++;
 300
 301         if (siv->rangeNext.u64 > siv->rangeEnd.u64 || *obj == UINT64_MAX) {
 302             /* end of range, check if there is more to parse */
 303             siv->lm = siv->unparsed_string[0] ? LM_UNPARSED : LM_END;
 304         }
 305         return true;
 306     case LM_END:
 307         error_setg(errp, "Fewer list elements expected");
 308         return false;
 309     default:
 310         abort();
 311     }
 312 }
 313
 314 static bool parse_type_size(Visitor *v, const char *name, uint64_t *obj,
 315                             Error **errp)
 316 {
 317     StringInputVisitor *siv = to_siv(v);
 318     uint64_t val;
 319
 320     assert(siv->lm == LM_NONE);
 321     if (!parse_option_size(name, siv->string, &val, errp)) {
 322         return false;
 323     }
 324
 325     *obj = val;
 326     return true;
 327 }
 328
 329 static bool parse_type_bool(Visitor *v, const char *name, bool *obj,
 330                             Error **errp)
 331 {
 332     StringInputVisitor *siv = to_siv(v);
 333
 334     assert(siv->lm == LM_NONE);
 335     return qapi_bool_parse(name ? name : "null", siv->string, obj, errp);
 336 }
 337
 338 static bool parse_type_str(Visitor *v, const char *name, char **obj,
 339                            Error **errp)
 340 {
 341     StringInputVisitor *siv = to_siv(v);
 342
 343     assert(siv->lm == LM_NONE);
 344     *obj = g_strdup(siv->string);
 345     return true;
 346 }
 347
 348 static bool parse_type_number(Visitor *v, const char *name, double *obj,
 349                               Error **errp)
 350 {
 351     StringInputVisitor *siv = to_siv(v);
 352     double val;
 353
 354     assert(siv->lm == LM_NONE);
 355     if (qemu_strtod_finite(siv->string, NULL, &val)) {
 356         error_setg(errp, QERR_INVALID_PARAMETER_TYPE, name ? name : "null",
 357                    "number");
 358         return false;
 359     }
 360
 361     *obj = val;
 362     return true;
 363 }
 364
 365 static bool parse_type_null(Visitor *v, const char *name, QNull **obj,
 366                             Error **errp)
 367 {
 368     StringInputVisitor *siv = to_siv(v);
 369
 370     assert(siv->lm == LM_NONE);
 371     *obj = NULL;
 372
 373     if (siv->string[0]) {
 374         error_setg(errp, QERR_INVALID_PARAMETER_TYPE, name ? name : "null",
 375                    "null");
 376         return false;
 377     }
 378
 379     *obj = qnull();
 380     return true;
 381 }
 382
 383 static void string_input_free(Visitor *v)
 384 {
 385     StringInputVisitor *siv = to_siv(v);
 386
 387     g_free(siv);
 388 }
 389
 390 Visitor *string_input_visitor_new(const char *str)
 391 {
 392     StringInputVisitor *v;
 393
 394     assert(str);
 395     v = g_malloc0(sizeof(*v));
 396
 397     v->visitor.type = VISITOR_INPUT;
 398     v->visitor.type_int64 = parse_type_int64;
 399     v->visitor.type_uint64 = parse_type_uint64;
 400     v->visitor.type_size = parse_type_size;
 401     v->visitor.type_bool = parse_type_bool;
 402     v->visitor.type_str = parse_type_str;
 403     v->visitor.type_number = parse_type_number;
 404     v->visitor.type_null = parse_type_null;
 405     v->visitor.start_list = start_list;
 406     v->visitor.next_list = next_list;
 407     v->visitor.check_list = check_list;
 408     v->visitor.end_list = end_list;
 409     v->visitor.free = string_input_free;
 410
 411     v->string = str;
 412     v->lm = LM_NONE;
 413     return &v->visitor;
 414 }