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Annotation of src/usr.bin/grep/mmfile.c, Revision 1.19

1.19    ! deraadt     1: /*     $OpenBSD: mmfile.c,v 1.18 2019/01/23 23:00:54 tedu 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/mman.h>
                     30: #include <sys/stat.h>
                     31:
                     32: #include <err.h>
                     33: #include <fcntl.h>
                     34: #include <stdlib.h>
                     35: #include <unistd.h>
                     36:
                     37: #include "grep.h"
                     38:
1.13      nicm       39: #ifndef SMALL
                     40:
1.1       deraadt    41: #define MAX_MAP_LEN 1048576
                     42:
                     43: mmf_t *
1.18      tedu       44: mmopen(int fd, struct stat *st)
1.1       deraadt    45: {
                     46:        mmf_t *mmf;
1.2       deraadt    47:
                     48:        mmf = grep_malloc(sizeof *mmf);
1.18      tedu       49:        if (st->st_size > SIZE_MAX) /* too big to mmap */
                     50:                goto ouch;
                     51:        mmf->len = (size_t)st->st_size;
1.19    ! deraadt    52:        mmf->fd = fd;
1.2       deraadt    53:        mmf->base = mmap(NULL, mmf->len, PROT_READ, MAP_PRIVATE, mmf->fd, (off_t)0);
1.7       tedu       54:        if (mmf->base == MAP_FAILED)
1.18      tedu       55:                goto ouch;
1.1       deraadt    56:        mmf->ptr = mmf->base;
                     57:        mmf->end = mmf->base + mmf->len;
                     58:        madvise(mmf->base, mmf->len, MADV_SEQUENTIAL);
                     59:        return mmf;
                     60:
1.18      tedu       61: ouch:
1.1       deraadt    62:        free(mmf);
                     63:        return NULL;
                     64: }
                     65:
                     66: void
                     67: mmclose(mmf_t *mmf)
                     68: {
                     69:        munmap(mmf->base, mmf->len);
                     70:        close(mmf->fd);
                     71:        free(mmf);
                     72: }
                     73:
                     74: char *
                     75: mmfgetln(mmf_t *mmf, size_t *l)
                     76: {
                     77:        static char *p;
                     78:
                     79:        if (mmf->ptr >= mmf->end)
                     80:                return NULL;
1.14      aschrijv   81:        for (p = mmf->ptr; mmf->ptr < mmf->end; ++mmf->ptr)
                     82:                if (*mmf->ptr == '\n')
                     83:                    break;
1.5       tedu       84:
1.1       deraadt    85:        *l = mmf->ptr - p;
                     86:        ++mmf->ptr;
                     87:        return p;
                     88: }
1.13      nicm       89:
                     90: #endif