lib/util.h

   1 /*
   2  * Copyright (c) 2008, 2009, 2010, 2011, 2012, 2013, 2014, 2015, 2016, 2017 Nicira, Inc.
   3  *
   4  * Licensed under the Apache License, Version 2.0 (the "License");
   5  * you may not use this file except in compliance with the License.
   6  * You may obtain a copy of the License at:
   7  *
   8  *     http://www.apache.org/licenses/LICENSE-2.0
   9  *
  10  * Unless required by applicable law or agreed to in writing, software
  11  * distributed under the License is distributed on an "AS IS" BASIS,
  12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  13  * See the License for the specific language governing permissions and
  14  * limitations under the License.
  15  */
  16
  17 #ifndef UTIL_H
  18 #define UTIL_H 1
  19
  20 #include <sys/types.h>
  21 #include <netinet/in.h>
  22 #include <arpa/inet.h>
  23 #include <inttypes.h>
  24 #include <limits.h>
  25 #include <stdarg.h>
  26 #include <stdio.h>
  27 #include <stdlib.h>
  28 #include <string.h>
  29 #include "compiler.h"
  30 #include "util.h"
  31 #include "openvswitch/util.h"
  32 #if defined(__aarch64__) && __GNUC__ >= 6
  33 #include <arm_neon.h>
  34 #endif
  35
  36 extern char *program_name;
  37
  38 #define __ARRAY_SIZE_NOCHECK(ARRAY) (sizeof(ARRAY) / sizeof((ARRAY)[0]))
  39 #if __GNUC__ && !defined(__cplusplus)
  40 /* return 0 for array types, 1 otherwise */
  41 #define __ARRAY_CHECK(ARRAY)                                    \
  42     !__builtin_types_compatible_p(typeof(ARRAY), typeof(&ARRAY[0]))
  43
  44 /* compile-time fail if not array */
  45 #define __ARRAY_FAIL(ARRAY) (sizeof(char[-2*!__ARRAY_CHECK(ARRAY)]))
  46 #define __ARRAY_SIZE(ARRAY)                                     \
  47     __builtin_choose_expr(__ARRAY_CHECK(ARRAY),                 \
  48         __ARRAY_SIZE_NOCHECK(ARRAY), __ARRAY_FAIL(ARRAY))
  49 #elif defined(__cplusplus)
  50 #define __ARRAY_SIZE(ARRAY) ( \
  51    0 * sizeof(reinterpret_cast<const ::Bad_arg_to_ARRAY_SIZE *>(ARRAY)) + \
  52    0 * sizeof(::Bad_arg_to_ARRAY_SIZE::check_type((ARRAY), &(ARRAY))) + \
  53    sizeof(ARRAY) / sizeof((ARRAY)[0]) )
  54
  55 struct Bad_arg_to_ARRAY_SIZE {
  56    class Is_pointer;
  57    class Is_array {};
  58    template <typename T>
  59    static Is_pointer check_type(const T *, const T * const *);
  60    static Is_array check_type(const void *, const void *);
  61 };
  62 #else
  63 #define __ARRAY_SIZE(ARRAY) __ARRAY_SIZE_NOCHECK(ARRAY)
  64 #endif
  65
  66
  67 /* This system's cache line size, in bytes.
  68  * Being wrong hurts performance but not correctness. */
  69 #define CACHE_LINE_SIZE 64
  70 BUILD_ASSERT_DECL(IS_POW2(CACHE_LINE_SIZE));
  71
  72 /* Cacheline marking is typically done using zero-sized array.
  73  * However MSVC doesn't like zero-sized array in struct/union.
  74  * C4200: https://msdn.microsoft.com/en-us/library/79wf64bc.aspx
  75  */
  76 typedef uint8_t OVS_CACHE_LINE_MARKER[1];
  77
  78 static inline void
  79 ovs_prefetch_range(const void *start, size_t size)
  80 {
  81     const char *addr = (const char *)start;
  82     size_t ofs;
  83
  84     for (ofs = 0; ofs < size; ofs += CACHE_LINE_SIZE) {
  85         OVS_PREFETCH(addr + ofs);
  86     }
  87 }
  88
  89 #ifndef MIN
  90 #define MIN(X, Y) ((X) < (Y) ? (X) : (Y))
  91 #endif
  92
  93 #ifndef MAX
  94 #define MAX(X, Y) ((X) > (Y) ? (X) : (Y))
  95 #endif
  96
  97 /* Comparisons for ints with modular arithmetic */
  98 #define INT_MOD_LT(a,b)     ((int) ((a)-(b)) < 0)
  99 #define INT_MOD_LEQ(a,b)    ((int) ((a)-(b)) <= 0)
 100 #define INT_MOD_GT(a,b)     ((int) ((a)-(b)) > 0)
 101 #define INT_MOD_GEQ(a,b)    ((int) ((a)-(b)) >= 0)
 102
 103 #define INT_MOD_MIN(a, b)   ((INT_MOD_LT(a, b)) ? (a) : (b))
 104 #define INT_MOD_MAX(a, b)   ((INT_MOD_GT(a, b)) ? (a) : (b))
 105
 106 #define OVS_NOT_REACHED() abort()
 107
 108 /* Use "%"PRIuSIZE to format size_t with printf(). */
 109 #ifdef _WIN32
 110 #define PRIdSIZE "Id"
 111 #define PRIiSIZE "Ii"
 112 #define PRIoSIZE "Io"
 113 #define PRIuSIZE "Iu"
 114 #define PRIxSIZE "Ix"
 115 #define PRIXSIZE "IX"
 116 #else
 117 #define PRIdSIZE "zd"
 118 #define PRIiSIZE "zi"
 119 #define PRIoSIZE "zo"
 120 #define PRIuSIZE "zu"
 121 #define PRIxSIZE "zx"
 122 #define PRIXSIZE "zX"
 123 #endif
 124
 125 #ifndef _WIN32
 126 typedef uint32_t HANDLE;
 127 #endif
 128
 129 #ifdef  __cplusplus
 130 extern "C" {
 131 #endif
 132
 133 #define set_program_name(name) \
 134         ovs_set_program_name(name, OVS_PACKAGE_VERSION)
 135
 136 const char *get_subprogram_name(void);
 137     void set_subprogram_name(const char *);
 138
 139 unsigned int get_page_size(void);
 140 long long int get_boot_time(void);
 141
 142 void ctl_timeout_setup(unsigned int secs);
 143
 144 void ovs_print_version(uint8_t min_ofp, uint8_t max_ofp);
 145
 146 void set_memory_locked(void);
 147 bool memory_locked(void);
 148
 149 OVS_NO_RETURN void out_of_memory(void);
 150 void *xmalloc(size_t) MALLOC_LIKE;
 151 void *xcalloc(size_t, size_t) MALLOC_LIKE;
 152 void *xzalloc(size_t) MALLOC_LIKE;
 153 void *xrealloc(void *, size_t);
 154 void *xmemdup(const void *, size_t) MALLOC_LIKE;
 155 char *xmemdup0(const char *, size_t) MALLOC_LIKE;
 156 char *xstrdup(const char *) MALLOC_LIKE;
 157 char *nullable_xstrdup(const char *) MALLOC_LIKE;
 158 bool nullable_string_is_equal(const char *a, const char *b);
 159 char *xasprintf(const char *format, ...) OVS_PRINTF_FORMAT(1, 2) MALLOC_LIKE;
 160 char *xvasprintf(const char *format, va_list) OVS_PRINTF_FORMAT(1, 0) MALLOC_LIKE;
 161 void *x2nrealloc(void *p, size_t *n, size_t s);
 162
 163 void *xmalloc_cacheline(size_t) MALLOC_LIKE;
 164 void *xzalloc_cacheline(size_t) MALLOC_LIKE;
 165 void free_cacheline(void *);
 166
 167 void ovs_strlcpy(char *dst, const char *src, size_t size);
 168 void ovs_strzcpy(char *dst, const char *src, size_t size);
 169
 170 int string_ends_with(const char *str, const char *suffix);
 171
 172 void *xmalloc_pagealign(size_t) MALLOC_LIKE;
 173 void free_pagealign(void *);
 174 void *xmalloc_size_align(size_t, size_t) MALLOC_LIKE;
 175 void free_size_align(void *);
 176
 177 /* The C standards say that neither the 'dst' nor 'src' argument to
 178  * memcpy() may be null, even if 'n' is zero.  This wrapper tolerates
 179  * the null case. */
 180 static inline void
 181 nullable_memcpy(void *dst, const void *src, size_t n)
 182 {
 183     if (n) {
 184         memcpy(dst, src, n);
 185     }
 186 }
 187
 188 /* The C standards say that the 'dst' argument to memset may not be
 189  * null, even if 'n' is zero.  This wrapper tolerates the null case. */
 190 static inline void
 191 nullable_memset(void *dst, int c, size_t n)
 192 {
 193     if (n) {
 194         memset(dst, c, n);
 195     }
 196 }
 197
 198 /* Copy string SRC to DST, but no more bytes than the shorter of DST or SRC.
 199  * DST and SRC must both be char arrays, not pointers, and with GNU C, this
 200  * raises a compiler error if either DST or SRC is a pointer instead of an
 201  * array. */
 202 #define ovs_strlcpy_arrays(DST, SRC) \
 203     ovs_strlcpy(DST, SRC, MIN(ARRAY_SIZE(DST), ARRAY_SIZE(SRC)))
 204
 205 OVS_NO_RETURN void ovs_abort(int err_no, const char *format, ...)
 206     OVS_PRINTF_FORMAT(2, 3);
 207 OVS_NO_RETURN void ovs_abort_valist(int err_no, const char *format, va_list)
 208     OVS_PRINTF_FORMAT(2, 0);
 209 OVS_NO_RETURN void ovs_fatal(int err_no, const char *format, ...)
 210     OVS_PRINTF_FORMAT(2, 3);
 211 OVS_NO_RETURN void ovs_fatal_valist(int err_no, const char *format, va_list)
 212     OVS_PRINTF_FORMAT(2, 0);
 213 void ovs_error(int err_no, const char *format, ...) OVS_PRINTF_FORMAT(2, 3);
 214 void ovs_error_valist(int err_no, const char *format, va_list)
 215     OVS_PRINTF_FORMAT(2, 0);
 216 const char *ovs_retval_to_string(int);
 217 const char *ovs_strerror(int);
 218 void ovs_hex_dump(FILE *, const void *, size_t, uintptr_t offset, bool ascii);
 219
 220 bool str_to_int(const char *, int base, int *);
 221 bool str_to_long(const char *, int base, long *);
 222 bool str_to_llong(const char *, int base, long long *);
 223 bool str_to_llong_with_tail(const char *, char **, int base, long long *);
 224 bool str_to_uint(const char *, int base, unsigned int *);
 225 bool str_to_ullong(const char *, int base, unsigned long long *);
 226 bool str_to_llong_range(const char *, int base, long long *, long long *);
 227
 228 bool ovs_scan(const char *s, const char *format, ...) OVS_SCANF_FORMAT(2, 3);
 229 bool ovs_scan_len(const char *s, int *n, const char *format, ...);
 230
 231 bool str_to_double(const char *, double *);
 232
 233 int hexit_value(unsigned char c);
 234 uintmax_t hexits_value(const char *s, size_t n, bool *ok);
 235
 236 int parse_int_string(const char *s, uint8_t *valuep, int field_width,
 237                      char **tail);
 238
 239 const char *english_list_delimiter(size_t index, size_t total);
 240
 241 char *get_cwd(void);
 242 #ifndef _WIN32
 243 char *dir_name(const char *file_name);
 244 char *base_name(const char *file_name);
 245 #endif
 246 char *abs_file_name(const char *dir, const char *file_name);
 247 bool is_file_name_absolute(const char *);
 248
 249 char *follow_symlinks(const char *filename);
 250
 251 void ignore(bool x OVS_UNUSED);
 252 \f
 253 /* Bitwise tests. */
 254
 255 /* Returns the number of trailing 0-bits in 'n'.  Undefined if 'n' == 0. */
 256 #if __GNUC__ >= 4
 257 static inline int
 258 raw_ctz(uint64_t n)
 259 {
 260     /* With GCC 4.7 on 32-bit x86, if a 32-bit integer is passed as 'n', using
 261      * a plain __builtin_ctzll() here always generates an out-of-line function
 262      * call.  The test below helps it to emit a single 'bsf' instruction. */
 263     return (__builtin_constant_p(n <= UINT32_MAX) && n <= UINT32_MAX
 264             ? __builtin_ctz(n)
 265             : __builtin_ctzll(n));
 266 }
 267
 268 static inline int
 269 raw_clz64(uint64_t n)
 270 {
 271     return __builtin_clzll(n);
 272 }
 273 #elif _MSC_VER
 274 static inline int
 275 raw_ctz(uint64_t n)
 276 {
 277 #ifdef _WIN64
 278     unsigned long r = 0;
 279     _BitScanForward64(&r, n);
 280     return r;
 281 #else
 282     unsigned long low = n, high, r = 0;
 283     if (_BitScanForward(&r, low)) {
 284         return r;
 285     }
 286     high = n >> 32;
 287     _BitScanForward(&r, high);
 288     return r + 32;
 289 #endif
 290 }
 291
 292 static inline int
 293 raw_clz64(uint64_t n)
 294 {
 295 #ifdef _WIN64
 296     unsigned long r = 0;
 297     _BitScanReverse64(&r, n);
 298     return 63 - r;
 299 #else
 300     unsigned long low, high = n >> 32, r = 0;
 301     if (_BitScanReverse(&r, high)) {
 302         return 31 - r;
 303     }
 304     low = n;
 305     _BitScanReverse(&r, low);
 306     return 63 - r;
 307 #endif
 308 }
 309 #else
 310 /* Defined in util.c. */
 311 int raw_ctz(uint64_t n);
 312 int raw_clz64(uint64_t n);
 313 #endif
 314
 315 /* Returns the number of trailing 0-bits in 'n', or 32 if 'n' is 0. */
 316 static inline int
 317 ctz32(uint32_t n)
 318 {
 319     return n ? raw_ctz(n) : 32;
 320 }
 321
 322 /* Returns the number of trailing 0-bits in 'n', or 64 if 'n' is 0. */
 323 static inline int
 324 ctz64(uint64_t n)
 325 {
 326     return n ? raw_ctz(n) : 64;
 327 }
 328
 329 /* Returns the number of leading 0-bits in 'n', or 32 if 'n' is 0. */
 330 static inline int
 331 clz32(uint32_t n)
 332 {
 333     return n ? raw_clz64(n) - 32 : 32;
 334 }
 335
 336 /* Returns the number of leading 0-bits in 'n', or 64 if 'n' is 0. */
 337 static inline int
 338 clz64(uint64_t n)
 339 {
 340     return n ? raw_clz64(n) : 64;
 341 }
 342
 343 /* Given a word 'n', calculates floor(log_2('n')).  This is equivalent
 344  * to finding the bit position of the most significant one bit in 'n'.  It is
 345  * an error to call this function with 'n' == 0. */
 346 static inline int
 347 log_2_floor(uint64_t n)
 348 {
 349     return 63 - raw_clz64(n);
 350 }
 351
 352 /* Given a word 'n', calculates ceil(log_2('n')).  It is an error to
 353  * call this function with 'n' == 0. */
 354 static inline int
 355 log_2_ceil(uint64_t n)
 356 {
 357     return log_2_floor(n) + !is_pow2(n);
 358 }
 359
 360 /* unsigned int count_1bits(uint64_t x):
 361  *
 362  * Returns the number of 1-bits in 'x', between 0 and 64 inclusive. */
 363 #if UINTPTR_MAX == UINT64_MAX
 364 static inline unsigned int
 365 count_1bits(uint64_t x)
 366 {
 367 #if (__GNUC__ >= 4 && __POPCNT__) || (defined(__aarch64__) && __GNUC__ >= 7)
 368     return __builtin_popcountll(x);
 369 #elif defined(__aarch64__) && __GNUC__ >= 6
 370     return vaddv_u8(vcnt_u8(vcreate_u8(x)));
 371 #else
 372     /* This portable implementation is the fastest one we know of for 64
 373      * bits, and about 3x faster than GCC 4.7 __builtin_popcountll(). */
 374     const uint64_t h55 = UINT64_C(0x5555555555555555);
 375     const uint64_t h33 = UINT64_C(0x3333333333333333);
 376     const uint64_t h0F = UINT64_C(0x0F0F0F0F0F0F0F0F);
 377     const uint64_t h01 = UINT64_C(0x0101010101010101);
 378     x -= (x >> 1) & h55;               /* Count of each 2 bits in-place. */
 379     x = (x & h33) + ((x >> 2) & h33);  /* Count of each 4 bits in-place. */
 380     x = (x + (x >> 4)) & h0F;          /* Count of each 8 bits in-place. */
 381     return (x * h01) >> 56;            /* Sum of all bytes. */
 382 #endif
 383 }
 384 #else /* Not 64-bit. */
 385 #if __GNUC__ >= 4 && __POPCNT__
 386 static inline unsigned int
 387 count_1bits_32__(uint32_t x)
 388 {
 389     return __builtin_popcount(x);
 390 }
 391 #else
 392 #define NEED_COUNT_1BITS_8 1
 393 extern const uint8_t count_1bits_8[256];
 394 static inline unsigned int
 395 count_1bits_32__(uint32_t x)
 396 {
 397     /* This portable implementation is the fastest one we know of for 32 bits,
 398      * and faster than GCC __builtin_popcount(). */
 399     return (count_1bits_8[x & 0xff] +
 400             count_1bits_8[(x >> 8) & 0xff] +
 401             count_1bits_8[(x >> 16) & 0xff] +
 402             count_1bits_8[x >> 24]);
 403 }
 404 #endif
 405 static inline unsigned int
 406 count_1bits(uint64_t x)
 407 {
 408     return count_1bits_32__(x) + count_1bits_32__(x >> 32);
 409 }
 410 #endif
 411
 412 /* Returns the rightmost 1-bit in 'x' (e.g. 01011000 => 00001000), or 0 if 'x'
 413  * is 0. */
 414 static inline uintmax_t
 415 rightmost_1bit(uintmax_t x)
 416 {
 417     return x & -x;
 418 }
 419
 420 /* Returns 'x' with its rightmost 1-bit changed to a zero (e.g. 01011000 =>
 421  * 01010000), or 0 if 'x' is 0. */
 422 static inline uintmax_t
 423 zero_rightmost_1bit(uintmax_t x)
 424 {
 425     return x & (x - 1);
 426 }
 427
 428 /* Returns the index of the rightmost 1-bit in 'x' (e.g. 01011000 => 3), or an
 429  * undefined value if 'x' is 0. */
 430 static inline int
 431 rightmost_1bit_idx(uint64_t x)
 432 {
 433     return ctz64(x);
 434 }
 435
 436 /* Returns the index of the leftmost 1-bit in 'x' (e.g. 01011000 => 6), or an
 437  * undefined value if 'x' is 0. */
 438 static inline uint32_t
 439 leftmost_1bit_idx(uint64_t x)
 440 {
 441     return log_2_floor(x);
 442 }
 443
 444 /* Return a ovs_be32 prefix in network byte order with 'plen' highest bits set.
 445  * Shift with 32 is undefined behavior, but we rather use 64-bit shift than
 446  * compare. */
 447 static inline ovs_be32 be32_prefix_mask(int plen)
 448 {
 449     return htonl((uint64_t)UINT32_MAX << (32 - plen));
 450 }
 451 \f
 452 /* Returns true if the 1-bits in 'super' are a superset of the 1-bits in 'sub',
 453  * false otherwise. */
 454 static inline bool
 455 uint_is_superset(uintmax_t super, uintmax_t sub)
 456 {
 457     return (super & sub) == sub;
 458 }
 459
 460 /* Returns true if the 1-bits in 'super' are a superset of the 1-bits in 'sub',
 461  * false otherwise. */
 462 static inline bool
 463 be16_is_superset(ovs_be16 super, ovs_be16 sub)
 464 {
 465     return (super & sub) == sub;
 466 }
 467
 468 /* Returns true if the 1-bits in 'super' are a superset of the 1-bits in 'sub',
 469  * false otherwise. */
 470 static inline bool
 471 be32_is_superset(ovs_be32 super, ovs_be32 sub)
 472 {
 473     return (super & sub) == sub;
 474 }
 475
 476 /* Returns true if the 1-bits in 'super' are a superset of the 1-bits in 'sub',
 477  * false otherwise. */
 478 static inline bool
 479 be64_is_superset(ovs_be64 super, ovs_be64 sub)
 480 {
 481     return (super & sub) == sub;
 482 }
 483 \f
 484 bool is_all_zeros(const void *, size_t);
 485 bool is_all_ones(const void *, size_t);
 486 bool is_all_byte(const void *, size_t, uint8_t byte);
 487 void or_bytes(void *dst, const void *src, size_t n);
 488 void bitwise_copy(const void *src, unsigned int src_len, unsigned int src_ofs,
 489                   void *dst, unsigned int dst_len, unsigned int dst_ofs,
 490                   unsigned int n_bits);
 491 void bitwise_zero(void *dst_, unsigned int dst_len, unsigned dst_ofs,
 492                   unsigned int n_bits);
 493 void bitwise_one(void *dst_, unsigned int dst_len, unsigned dst_ofs,
 494                  unsigned int n_bits);
 495 bool bitwise_is_all_zeros(const void *, unsigned int len, unsigned int ofs,
 496                           unsigned int n_bits);
 497 unsigned int bitwise_scan(const void *, unsigned int len,
 498                           bool target, unsigned int start, unsigned int end);
 499 int bitwise_rscan(const void *, unsigned int len, bool target,
 500                   int start, int end);
 501 void bitwise_put(uint64_t value,
 502                  void *dst, unsigned int dst_len, unsigned int dst_ofs,
 503                  unsigned int n_bits);
 504 uint64_t bitwise_get(const void *src, unsigned int src_len,
 505                      unsigned int src_ofs, unsigned int n_bits);
 506 bool bitwise_get_bit(const void *src, unsigned int len, unsigned int ofs);
 507 void bitwise_put0(void *dst, unsigned int len, unsigned int ofs);
 508 void bitwise_put1(void *dst, unsigned int len, unsigned int ofs);
 509 void bitwise_put_bit(void *dst, unsigned int len, unsigned int ofs, bool);
 510 void bitwise_toggle_bit(void *dst, unsigned int len, unsigned int ofs);
 511
 512 /* Returns non-zero if the parameters have equal value. */
 513 static inline int
 514 ovs_u128_equals(const ovs_u128 a, const ovs_u128 b)
 515 {
 516     return (a.u64.hi == b.u64.hi) && (a.u64.lo == b.u64.lo);
 517 }
 518
 519 /* Returns true if 'val' is 0. */
 520 static inline bool
 521 ovs_u128_is_zero(const ovs_u128 val)
 522 {
 523     return !(val.u64.hi || val.u64.lo);
 524 }
 525
 526 /* Returns true if 'val' is all ones. */
 527 static inline bool
 528 ovs_u128_is_ones(const ovs_u128 val)
 529 {
 530     return ovs_u128_equals(val, OVS_U128_MAX);
 531 }
 532
 533 /* Returns non-zero if the parameters have equal value. */
 534 static inline int
 535 ovs_be128_equals(const ovs_be128 a, const ovs_be128 b)
 536 {
 537     return (a.be64.hi == b.be64.hi) && (a.be64.lo == b.be64.lo);
 538 }
 539
 540 /* Returns true if 'val' is 0. */
 541 static inline bool
 542 ovs_be128_is_zero(const ovs_be128 val)
 543 {
 544     return !(val.be64.hi || val.be64.lo);
 545 }
 546
 547 static inline ovs_u128
 548 ovs_u128_and(const ovs_u128 a, const ovs_u128 b)
 549 {
 550     ovs_u128 dst;
 551
 552     dst.u64.hi = a.u64.hi & b.u64.hi;
 553     dst.u64.lo = a.u64.lo & b.u64.lo;
 554
 555     return dst;
 556 }
 557
 558 static inline bool
 559 ovs_be128_is_superset(ovs_be128 super, ovs_be128 sub)
 560 {
 561     return (be64_is_superset(super.be64.hi, sub.be64.hi) &&
 562             be64_is_superset(super.be64.lo, sub.be64.lo));
 563 }
 564
 565 static inline bool
 566 ovs_u128_is_superset(ovs_u128 super, ovs_u128 sub)
 567 {
 568     return (uint_is_superset(super.u64.hi, sub.u64.hi) &&
 569             uint_is_superset(super.u64.lo, sub.u64.lo));
 570 }
 571
 572 void xsleep(unsigned int seconds);
 573 void xnanosleep(uint64_t nanoseconds);
 574
 575 bool is_stdout_a_tty(void);
 576
 577 #ifdef _WIN32
 578 \f
 579 char *ovs_format_message(int error);
 580 char *ovs_lasterror_to_string(void);
 581 int ftruncate(int fd, off_t length);
 582 #endif
 583
 584 #ifdef  __cplusplus
 585 }
 586 #endif
 587
 588 #endif /* util.h */