0b79eac642
Currently we don't accept writable file mmap()s, as there is no system in place to guarantee dirty buffers would make it back to disk. But we can actually accept MAP_SHARED for PROT_READ mappings, meaning the ranges aren't writable at all (and no private copy is made as with MAP_PRIVATE), as it turns out a fairly large class of usage. . fail writable MAP_SHARED mappings at runtime . reduces some minix-specific patches . lets binutils gold build on minix without further patching Change-Id: If2896c0a555328ac5b324afa706063fc6d86519e
260 lines
6.6 KiB
C
260 lines
6.6 KiB
C
/* $NetBSD: cdbr.c,v 1.4 2012/09/27 00:37:43 joerg Exp $ */
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/*-
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* Copyright (c) 2010 The NetBSD Foundation, Inc.
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* All rights reserved.
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*
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* This code is derived from software contributed to The NetBSD Foundation
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* by Joerg Sonnenberger.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
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* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#if HAVE_NBTOOL_CONFIG_H
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#include "nbtool_config.h"
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#endif
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#include <sys/cdefs.h>
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__RCSID("$NetBSD: cdbr.c,v 1.4 2012/09/27 00:37:43 joerg Exp $");
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#include "namespace.h"
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#if !HAVE_NBTOOL_CONFIG_H
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#include <sys/bitops.h>
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#endif
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#if !HAVE_NBTOOL_CONFIG_H || HAVE_SYS_ENDIAN_H
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#include <sys/endian.h>
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#endif
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#include <sys/mman.h>
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#include <sys/stat.h>
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#include <cdbr.h>
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#include <errno.h>
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#include <fcntl.h>
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#include <inttypes.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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#ifdef __weak_alias
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__weak_alias(cdbr_close,_cdbr_close)
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__weak_alias(cdbr_find,_cdbr_find)
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__weak_alias(cdbr_get,_cdbr_get)
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__weak_alias(cdbr_open,_cdbr_open)
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#endif
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#if HAVE_NBTOOL_CONFIG_H
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#define fast_divide32_prepare(d,m,s1,s2) (void)0
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#define fast_remainder32(v,d,m,s1,s2) (v%d)
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#endif
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struct cdbr {
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uint8_t *mmap_base;
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size_t mmap_size;
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uint8_t *hash_base;
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uint8_t *offset_base;
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uint8_t *data_base;
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uint32_t data_size;
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uint32_t entries;
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uint32_t entries_index;
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uint32_t seed;
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uint8_t offset_size;
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uint8_t index_size;
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uint32_t entries_m;
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uint32_t entries_index_m;
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uint8_t entries_s1, entries_s2;
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uint8_t entries_index_s1, entries_index_s2;
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};
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/* ARGSUSED */
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struct cdbr *
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cdbr_open(const char *path, int flags)
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{
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uint8_t buf[40];
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int fd;
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struct cdbr *cdbr;
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struct stat sb;
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if ((fd = open(path, O_RDONLY)) == -1)
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return NULL;
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errno = EINVAL;
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if (fstat(fd, &sb) == -1 ||
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read(fd, buf, sizeof(buf)) != sizeof(buf) ||
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memcmp(buf, "NBCDB\n\0\001", 8) ||
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(cdbr = malloc(sizeof(*cdbr))) == NULL) {
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close(fd);
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return NULL;
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}
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cdbr->data_size = le32dec(buf + 24);
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cdbr->entries = le32dec(buf + 28);
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cdbr->entries_index = le32dec(buf + 32);
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cdbr->seed = le32dec(buf + 36);
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if (cdbr->data_size < 0x100)
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cdbr->offset_size = 1;
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else if (cdbr->data_size < 0x10000)
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cdbr->offset_size = 2;
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else
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cdbr->offset_size = 4;
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if (cdbr->entries_index < 0x100)
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cdbr->index_size = 1;
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else if (cdbr->entries_index < 0x10000)
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cdbr->index_size = 2;
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else
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cdbr->index_size = 4;
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cdbr->mmap_size = (size_t)sb.st_size;
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cdbr->mmap_base = mmap(NULL, cdbr->mmap_size, PROT_READ, MAP_FILE|MAP_SHARED, fd, 0);
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close(fd);
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if (cdbr->mmap_base == MAP_FAILED) {
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free(cdbr);
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return NULL;
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}
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cdbr->hash_base = cdbr->mmap_base + 40;
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cdbr->offset_base = cdbr->hash_base + cdbr->entries_index * cdbr->index_size;
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if (cdbr->entries_index * cdbr->index_size % cdbr->offset_size)
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cdbr->offset_base += cdbr->offset_size -
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cdbr->entries_index * cdbr->index_size % cdbr->offset_size;
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cdbr->data_base = cdbr->offset_base + (cdbr->entries + 1) * cdbr->offset_size;
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if (cdbr->hash_base < cdbr->mmap_base ||
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cdbr->offset_base < cdbr->mmap_base ||
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cdbr->data_base < cdbr->mmap_base ||
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cdbr->data_base + cdbr->data_size < cdbr->mmap_base ||
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cdbr->data_base + cdbr->data_size >
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cdbr->mmap_base + cdbr->mmap_size) {
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errno = EINVAL;
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cdbr_close(cdbr);
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return NULL;
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}
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if (cdbr->entries) {
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fast_divide32_prepare(cdbr->entries, &cdbr->entries_m,
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&cdbr->entries_s1, &cdbr->entries_s2);
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}
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if (cdbr->entries_index) {
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fast_divide32_prepare(cdbr->entries_index,
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&cdbr->entries_index_m,
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&cdbr->entries_index_s1, &cdbr->entries_index_s2);
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}
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return cdbr;
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}
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static inline uint32_t
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get_uintX(const uint8_t *addr, uint32_t idx, int size)
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{
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addr += idx * size;
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if (size == 4)
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return /* LINTED */le32toh(*(const uint32_t *)addr);
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else if (size == 2)
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return /* LINTED */le16toh(*(const uint16_t *)addr);
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else
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return *addr;
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}
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uint32_t
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cdbr_entries(struct cdbr *cdbr)
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{
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return cdbr->entries;
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}
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int
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cdbr_get(struct cdbr *cdbr, uint32_t idx, const void **data, size_t *data_len)
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{
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uint32_t start, end;
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if (idx >= cdbr->entries) {
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errno = EINVAL;
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return -1;
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}
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start = get_uintX(cdbr->offset_base, idx, cdbr->offset_size);
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end = get_uintX(cdbr->offset_base, idx + 1, cdbr->offset_size);
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if (start > end) {
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errno = EIO;
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return -1;
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}
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if (end > cdbr->data_size) {
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errno = EIO;
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return -1;
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}
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*data = cdbr->data_base + start;
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*data_len = end - start;
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return 0;
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}
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int
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cdbr_find(struct cdbr *cdbr, const void *key, size_t key_len,
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const void **data, size_t *data_len)
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{
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uint32_t hashes[3], idx;
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if (cdbr->entries_index == 0) {
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errno = EINVAL;
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return -1;
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}
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mi_vector_hash(key, key_len, cdbr->seed, hashes);
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hashes[0] = fast_remainder32(hashes[0], cdbr->entries_index,
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cdbr->entries_index_m, cdbr->entries_index_s1,
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cdbr->entries_index_s2);
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hashes[1] = fast_remainder32(hashes[1], cdbr->entries_index,
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cdbr->entries_index_m, cdbr->entries_index_s1,
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cdbr->entries_index_s2);
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hashes[2] = fast_remainder32(hashes[2], cdbr->entries_index,
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cdbr->entries_index_m, cdbr->entries_index_s1,
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cdbr->entries_index_s2);
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idx = get_uintX(cdbr->hash_base, hashes[0], cdbr->index_size);
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idx += get_uintX(cdbr->hash_base, hashes[1], cdbr->index_size);
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idx += get_uintX(cdbr->hash_base, hashes[2], cdbr->index_size);
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return cdbr_get(cdbr, fast_remainder32(idx, cdbr->entries,
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cdbr->entries_m, cdbr->entries_s1, cdbr->entries_s2), data,
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data_len);
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}
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void
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cdbr_close(struct cdbr *cdbr)
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{
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munmap(cdbr->mmap_base, cdbr->mmap_size);
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free(cdbr);
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}
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