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Annotation of src/usr.bin/grep/mmfile.c, Revision 1.12

1.12    ! otto        1: /*     $OpenBSD: mmfile.c,v 1.11 2006/09/19 05:52:23 otto 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:
                     40: #define MAX_MAP_LEN 1048576
                     41:
                     42: mmf_t *
                     43: mmopen(char *fn, char *mode)
                     44: {
                     45:        mmf_t *mmf;
                     46:        struct stat st;
                     47:
                     48:        /* XXX ignore mode for now */
                     49:        mode = mode;
1.2       deraadt    50:
                     51:        mmf = grep_malloc(sizeof *mmf);
1.1       deraadt    52:        if ((mmf->fd = open(fn, O_RDONLY)) == -1)
                     53:                goto ouch1;
                     54:        if (fstat(mmf->fd, &st) == -1)
                     55:                goto ouch2;
1.2       deraadt    56:        if (st.st_size > SIZE_T_MAX) /* too big to mmap */
1.1       deraadt    57:                goto ouch2;
1.12    ! otto       58:        if (!S_ISREG(st.st_mode)) /* only mmap regular files */
1.1       deraadt    59:                goto ouch2;
                     60:        mmf->len = (size_t)st.st_size;
1.2       deraadt    61:        mmf->base = mmap(NULL, mmf->len, PROT_READ, MAP_PRIVATE, mmf->fd, (off_t)0);
1.7       tedu       62:        if (mmf->base == MAP_FAILED)
1.1       deraadt    63:                goto ouch2;
                     64:        mmf->ptr = mmf->base;
                     65:        mmf->end = mmf->base + mmf->len;
                     66:        madvise(mmf->base, mmf->len, MADV_SEQUENTIAL);
                     67:        return mmf;
                     68:
                     69: ouch2:
                     70:        close(mmf->fd);
                     71: ouch1:
                     72:        free(mmf);
                     73:        return NULL;
                     74: }
                     75:
                     76: void
                     77: mmclose(mmf_t *mmf)
                     78: {
                     79:        munmap(mmf->base, mmf->len);
                     80:        close(mmf->fd);
                     81:        free(mmf);
                     82: }
                     83:
                     84: char *
                     85: mmfgetln(mmf_t *mmf, size_t *l)
                     86: {
                     87:        static char *p;
                     88:
                     89:        if (mmf->ptr >= mmf->end)
                     90:                return NULL;
1.9       otto       91:     for (p = mmf->ptr; mmf->ptr < mmf->end; ++mmf->ptr)
                     92:         if (*mmf->ptr == '\n')
                     93:             break;
1.5       tedu       94:
1.1       deraadt    95:        *l = mmf->ptr - p;
                     96:        ++mmf->ptr;
                     97:        return p;
                     98: }