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Annotation of src/usr.bin/grep/mmfile.c, Revision 1.15

1.15    ! brad        1: /*     $OpenBSD: mmfile.c,v 1.14 2011/07/17 12:17:10 aschrijver Exp $  */
1.3       deraadt     2:
1.1       deraadt     3: /*-
                      4:  * Copyright (c) 1999 James Howard and Dag-Erling Coïdan Smørgrav
                      5:  * All rights reserved.
                      6:  *
                      7:  * Redistribution and use in source and binary forms, with or without
                      8:  * modification, are permitted provided that the following conditions
                      9:  * are met:
                     10:  * 1. Redistributions of source code must retain the above copyright
                     11:  *    notice, this list of conditions and the following disclaimer.
                     12:  * 2. Redistributions in binary form must reproduce the above copyright
                     13:  *    notice, this list of conditions and the following disclaimer in the
                     14:  *    documentation and/or other materials provided with the distribution.
                     15:  *
                     16:  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
                     17:  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
                     18:  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
                     19:  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
                     20:  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
                     21:  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
                     22:  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
                     23:  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
                     24:  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
                     25:  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
                     26:  * SUCH DAMAGE.
                     27:  */
                     28:
                     29: #include <sys/param.h>
                     30: #include <sys/mman.h>
                     31: #include <sys/stat.h>
                     32:
                     33: #include <err.h>
                     34: #include <fcntl.h>
                     35: #include <stdlib.h>
                     36: #include <unistd.h>
                     37:
                     38: #include "grep.h"
                     39:
1.13      nicm       40: #ifndef SMALL
                     41:
1.1       deraadt    42: #define MAX_MAP_LEN 1048576
                     43:
                     44: mmf_t *
                     45: mmopen(char *fn, char *mode)
                     46: {
                     47:        mmf_t *mmf;
                     48:        struct stat st;
                     49:
1.15    ! brad       50:        if (*mode != 'r')
        !            51:                return NULL;
1.2       deraadt    52:
                     53:        mmf = grep_malloc(sizeof *mmf);
1.1       deraadt    54:        if ((mmf->fd = open(fn, O_RDONLY)) == -1)
                     55:                goto ouch1;
                     56:        if (fstat(mmf->fd, &st) == -1)
                     57:                goto ouch2;
1.2       deraadt    58:        if (st.st_size > SIZE_T_MAX) /* too big to mmap */
1.1       deraadt    59:                goto ouch2;
1.12      otto       60:        if (!S_ISREG(st.st_mode)) /* only mmap regular files */
1.1       deraadt    61:                goto ouch2;
                     62:        mmf->len = (size_t)st.st_size;
1.2       deraadt    63:        mmf->base = mmap(NULL, mmf->len, PROT_READ, MAP_PRIVATE, mmf->fd, (off_t)0);
1.7       tedu       64:        if (mmf->base == MAP_FAILED)
1.1       deraadt    65:                goto ouch2;
                     66:        mmf->ptr = mmf->base;
                     67:        mmf->end = mmf->base + mmf->len;
                     68:        madvise(mmf->base, mmf->len, MADV_SEQUENTIAL);
                     69:        return mmf;
                     70:
                     71: ouch2:
                     72:        close(mmf->fd);
                     73: ouch1:
                     74:        free(mmf);
                     75:        return NULL;
                     76: }
                     77:
                     78: void
                     79: mmclose(mmf_t *mmf)
                     80: {
                     81:        munmap(mmf->base, mmf->len);
                     82:        close(mmf->fd);
                     83:        free(mmf);
                     84: }
                     85:
                     86: char *
                     87: mmfgetln(mmf_t *mmf, size_t *l)
                     88: {
                     89:        static char *p;
                     90:
                     91:        if (mmf->ptr >= mmf->end)
                     92:                return NULL;
1.14      aschrijv   93:        for (p = mmf->ptr; mmf->ptr < mmf->end; ++mmf->ptr)
                     94:                if (*mmf->ptr == '\n')
                     95:                    break;
1.5       tedu       96:
1.1       deraadt    97:        *l = mmf->ptr - p;
                     98:        ++mmf->ptr;
                     99:        return p;
                    100: }
1.13      nicm      101:
                    102: #endif