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Annotation of src/usr.bin/grep/mmfile.c, Revision 1.5

1.5     ! tedu        1: /*     $OpenBSD: mmfile.c,v 1.4 2003/06/23 07:52:18 deraadt 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
1.5     ! tedu       41: #define BLOCKSIZE 32768
1.1       deraadt    42:
                     43: mmf_t *
                     44: mmopen(char *fn, char *mode)
                     45: {
                     46:        mmf_t *mmf;
                     47:        struct stat st;
                     48:
                     49:        /* XXX ignore mode for now */
                     50:        mode = mode;
1.2       deraadt    51:
                     52:        mmf = grep_malloc(sizeof *mmf);
1.1       deraadt    53:        if ((mmf->fd = open(fn, O_RDONLY)) == -1)
                     54:                goto ouch1;
                     55:        if (fstat(mmf->fd, &st) == -1)
                     56:                goto ouch2;
1.2       deraadt    57:        if (st.st_size > SIZE_T_MAX) /* too big to mmap */
1.1       deraadt    58:                goto ouch2;
                     59:        if ((st.st_mode & S_IFREG) == 0) /* only mmap regular files */
                     60:                goto ouch2;
                     61:        mmf->len = (size_t)st.st_size;
1.2       deraadt    62:        mmf->base = mmap(NULL, mmf->len, PROT_READ, MAP_PRIVATE, mmf->fd, (off_t)0);
1.1       deraadt    63:        if (mmf->base == NULL)
                     64:                goto ouch2;
                     65:        mmf->ptr = mmf->base;
                     66:        mmf->end = mmf->base + mmf->len;
                     67:        madvise(mmf->base, mmf->len, MADV_SEQUENTIAL);
                     68:        return mmf;
                     69:
                     70: ouch2:
                     71:        close(mmf->fd);
                     72: ouch1:
                     73:        free(mmf);
                     74:        return NULL;
                     75: }
                     76:
                     77: void
                     78: mmclose(mmf_t *mmf)
                     79: {
                     80:        munmap(mmf->base, mmf->len);
                     81:        close(mmf->fd);
                     82:        free(mmf);
                     83: }
                     84:
                     85: char *
                     86: mmfgetln(mmf_t *mmf, size_t *l)
                     87: {
                     88:        static char *p;
                     89:
                     90:        if (mmf->ptr >= mmf->end)
                     91:                return NULL;
1.5     ! tedu       92:        if ((lflag || qflag) &! boleol) {
        !            93:                /* Find starting point to search. */
        !            94:                if (mmf->ptr == mmf->base)
        !            95:                        p = mmf->ptr;
        !            96:                else
        !            97:                        p = mmf->ptr - maxPatternLen;
        !            98:                /* Move the start pointer ahead for next iteration */
        !            99:                if (mmf->end - mmf->ptr > BLOCKSIZE)
        !           100:                        mmf->ptr += BLOCKSIZE;
        !           101:                else
        !           102:                        mmf->ptr = mmf->end;
        !           103:        } else {
        !           104:                for (p = mmf->ptr; mmf->ptr < mmf->end; ++mmf->ptr)
        !           105:                        if (*mmf->ptr == '\n')
        !           106:                                break;
        !           107:        }
        !           108:
1.1       deraadt   109:        *l = mmf->ptr - p;
                    110:        ++mmf->ptr;
                    111:        return p;
                    112: }
                    113:
                    114: long
                    115: mmtell(mmf_t *mmf)
                    116: {
1.4       deraadt   117:        return mmf->ptr - mmf->base;
1.1       deraadt   118: }
                    119:
                    120: void
                    121: mmrewind(mmf_t *mmf)
                    122: {
1.4       deraadt   123:        mmf->ptr = mmf->base;
1.1       deraadt   124: }