LXR qemu/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
  22typedef 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
  38typedef union RangeElement {
  39    int64_t i64;
  40    uint64_t u64;
  41} RangeElement;
  42
  43struct 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
  58static StringInputVisitor *to_siv(Visitor *v)
  59{
  60    return container_of(v, StringInputVisitor, visitor);
  61}
  62
  63static 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
  86static 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
 106static 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
 123static 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
 134static 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
 182static 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
 224static 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
 272static 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
 314static 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
 329static 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
 338static 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
 348static 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
 365static 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
 383static void string_input_free(Visitor *v)
 384{
 385    StringInputVisitor *siv = to_siv(v);
 386
 387    g_free(siv);
 388}
 389
 390Visitor *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}
 415