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https://github.com/freebsd/freebsd-src
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195 lines
4.7 KiB
C
195 lines
4.7 KiB
C
![]() |
/* $Id: dbm_map.c,v 1.7 2016/10/22 10:09:27 schwarze Exp $ */
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/*
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* Copyright (c) 2016 Ingo Schwarze <schwarze@openbsd.org>
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*
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* Permission to use, copy, modify, and distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
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* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*
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* Low-level routines for the map-based version
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* of the mandoc database, for read-only access.
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* The interface is defined in "dbm_map.h".
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*/
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#include "config.h"
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#include <sys/mman.h>
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#include <sys/stat.h>
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#include <sys/types.h>
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#if HAVE_ENDIAN
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#include <endian.h>
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#elif HAVE_SYS_ENDIAN
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#include <sys/endian.h>
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#elif HAVE_NTOHL
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#include <arpa/inet.h>
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#endif
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#if HAVE_ERR
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#include <err.h>
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#endif
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#include <errno.h>
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#include <fcntl.h>
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#include <regex.h>
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#include <stdint.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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#include "mansearch.h"
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#include "dbm_map.h"
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#include "dbm.h"
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static struct stat st;
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static char *dbm_base;
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static int ifd;
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static int32_t max_offset;
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/*
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* Open a disk-based database for read-only access.
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* Validate the file format as far as it is not mandoc-specific.
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* Return 0 on success. Return -1 and set errno on failure.
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*/
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int
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dbm_map(const char *fname)
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{
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int save_errno;
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const int32_t *magic;
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if ((ifd = open(fname, O_RDONLY)) == -1)
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return -1;
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if (fstat(ifd, &st) == -1)
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goto fail;
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if (st.st_size < 5) {
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warnx("dbm_map(%s): File too short", fname);
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errno = EFTYPE;
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goto fail;
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}
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if (st.st_size > INT32_MAX) {
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errno = EFBIG;
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goto fail;
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}
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if ((dbm_base = mmap(NULL, st.st_size, PROT_READ, MAP_SHARED,
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ifd, 0)) == MAP_FAILED)
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goto fail;
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magic = dbm_getint(0);
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if (be32toh(*magic) != MANDOCDB_MAGIC) {
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if (strncmp(dbm_base, "SQLite format 3", 15))
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warnx("dbm_map(%s): "
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"Bad initial magic %x (expected %x)",
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fname, be32toh(*magic), MANDOCDB_MAGIC);
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else
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warnx("dbm_map(%s): "
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"Obsolete format based on SQLite 3",
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fname);
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errno = EFTYPE;
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goto fail;
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}
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magic = dbm_getint(1);
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if (be32toh(*magic) != MANDOCDB_VERSION) {
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warnx("dbm_map(%s): Bad version number %d (expected %d)",
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fname, be32toh(*magic), MANDOCDB_VERSION);
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errno = EFTYPE;
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goto fail;
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}
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max_offset = be32toh(*dbm_getint(3)) + sizeof(int32_t);
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if (st.st_size != max_offset) {
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warnx("dbm_map(%s): Inconsistent file size %lld (expected %d)",
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fname, (long long)st.st_size, max_offset);
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errno = EFTYPE;
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goto fail;
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}
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if ((magic = dbm_get(*dbm_getint(3))) == NULL) {
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errno = EFTYPE;
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goto fail;
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}
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if (be32toh(*magic) != MANDOCDB_MAGIC) {
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warnx("dbm_map(%s): Bad final magic %x (expected %x)",
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fname, be32toh(*magic), MANDOCDB_MAGIC);
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errno = EFTYPE;
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goto fail;
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}
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return 0;
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fail:
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save_errno = errno;
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close(ifd);
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errno = save_errno;
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return -1;
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}
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void
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dbm_unmap(void)
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{
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if (munmap(dbm_base, st.st_size) == -1)
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warn("dbm_unmap: munmap");
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if (close(ifd) == -1)
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warn("dbm_unmap: close");
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dbm_base = (char *)-1;
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}
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/*
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* Take a raw integer as it was read from the database.
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* Interpret it as an offset into the database file
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* and return a pointer to that place in the file.
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*/
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void *
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dbm_get(int32_t offset)
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{
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offset = be32toh(offset);
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if (offset < 0) {
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warnx("dbm_get: Database corrupt: offset %d", offset);
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return NULL;
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}
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if (offset >= max_offset) {
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warnx("dbm_get: Database corrupt: offset %d > %d",
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offset, max_offset);
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return NULL;
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}
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return dbm_base + offset;
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}
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/*
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* Assume the database starts with some integers.
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* Assume they are numbered starting from 0, increasing.
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* Get a pointer to one with the number "offset".
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*/
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int32_t *
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dbm_getint(int32_t offset)
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{
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return (int32_t *)dbm_base + offset;
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}
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/*
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* The reverse of dbm_get().
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* Take pointer into the database file
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* and convert it to the raw integer
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* that would be used to refer to that place in the file.
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*/
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int32_t
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dbm_addr(const void *p)
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{
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return htobe32((char *)p - dbm_base);
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}
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int
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dbm_match(const struct dbm_match *match, const char *str)
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{
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switch (match->type) {
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case DBM_EXACT:
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return strcmp(str, match->str) == 0;
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case DBM_SUB:
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return strcasestr(str, match->str) != NULL;
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case DBM_REGEX:
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return regexec(match->re, str, 0, NULL, 0) == 0;
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default:
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abort();
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}
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}
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