103 lines
2.8 KiB
C
103 lines
2.8 KiB
C
/* $OpenBSD: mmfile.c,v 1.11 2006/09/19 05:52:23 otto Exp $ */
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/*-
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* Copyright (c) 1999 James Howard and Dag-Erling Coïdan Smørgrav
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* All rights reserved.
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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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* 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 the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT 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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#include <sys/param.h>
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#include <sys/mman.h>
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#include <sys/stat.h>
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#include <err.h>
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#include <fcntl.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include "grep.h"
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#define MAX_MAP_LEN 1048576
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mmf_t *
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mmopen(char *fn, char *mode)
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{
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mmf_t *mmf;
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struct stat st;
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/* XXX ignore mode for now */
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mode = mode;
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mmf = grep_malloc(sizeof *mmf);
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if ((mmf->fd = open(fn, O_RDONLY)) == -1)
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goto ouch1;
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if (fstat(mmf->fd, &st) == -1)
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goto ouch2;
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if (st.st_size > SIZE_T_MAX) /* too big to mmap */
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goto ouch2;
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if (!S_ISREG(st.st_mode)) /* only mmap regular files */
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goto ouch2;
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mmf->len = (size_t)st.st_size;
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mmf->base = mmap(NULL, mmf->len, PROT_READ, MAP_PRIVATE, mmf->fd, (off_t)0);
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if (mmf->base == MAP_FAILED)
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goto ouch2;
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mmf->ptr = mmf->base;
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mmf->end = mmf->base + mmf->len;
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#ifndef __minix
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madvise(mmf->base, mmf->len, MADV_SEQUENTIAL);
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#endif
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return mmf;
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ouch2:
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close(mmf->fd);
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ouch1:
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free(mmf);
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return NULL;
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}
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void
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mmclose(mmf_t *mmf)
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{
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munmap(mmf->base, mmf->len);
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close(mmf->fd);
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free(mmf);
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}
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char *
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mmfgetln(mmf_t *mmf, size_t *l)
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{
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static unsigned char *p;
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char *start = mmf->ptr; /* Remove speed bump */
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char *end = mmf->end; /* Remove speed bump */
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if (start >= end)
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return NULL;
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for (p = mmf->ptr; mmf->ptr < mmf->end; ++mmf->ptr)
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if (*mmf->ptr == '\n')
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break;
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*l = mmf->ptr - p;
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++mmf->ptr;
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return p;
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}
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