2 * Copyright (c) 2004,2005 The DragonFly Project. All rights reserved.
4 * This code is derived from software contributed to The DragonFly Project
5 * by Matthew Dillon <dillon@backplane.com>
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in
15 * the documentation and/or other materials provided with the
17 * 3. Neither the name of The DragonFly Project nor the names of its
18 * contributors may be used to endorse or promote products derived
19 * from this software without specific, prior written permission.
21 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
22 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
23 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
24 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
25 * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
26 * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
27 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
28 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
29 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
30 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
31 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34 * $DragonFly: src/sbin/jscan/jfile.c,v 1.1 2005/03/07 02:38:28 dillon Exp $
40 * Open a journal for directional scanning
43 jopen_stream(const char *path, enum jdirection jdir)
47 jf = malloc(sizeof(struct jfile));
48 bzero(jf, sizeof(struct jfile));
49 if ((jf->jf_fp = fopen(path, "r")) == NULL) {
53 jf->jf_direction = jdir;
55 if (jdir == JF_BACKWARDS) {
56 fseeko(jf->jf_fp, 0L, SEEK_END);
57 jf->jf_pos = ftello(jf->jf_fp);
63 * Close a previously opened journal, clean up any side allocations.
66 jclose_stream(struct jfile *jf)
72 while ((jd = jf->jf_saved) != NULL) {
73 jf->jf_saved = jd->jd_next;
80 * Align us to the next 16 byte boundary. If scanning forwards we align
81 * forwards if not already aligned. If scanning backwards we align
82 * backwards if not already aligned.
85 jalign(struct jfile *jf)
87 if (jf->jf_direction == JF_FORWARDS) {
88 jf->jf_pos = (jf->jf_pos + 15) & ~15;
89 fseeko(jf->jf_fp, jf->jf_pos, SEEK_SET);
91 jf->jf_pos = jf->jf_pos & ~15;
96 * Read data from a journal forwards or backwards. Note that the file
97 * pointer's actual seek position does not match jf_pos in the reverse
98 * scan case. Callers should never access jf_fp directly.
101 jread(struct jfile *jf, void *buf, int bytes)
103 if (jf->jf_direction == JF_FORWARDS) {
104 if (fread(buf, bytes, 1, jf->jf_fp) == 1) {
108 fseeko(jf->jf_fp, jf->jf_pos, SEEK_SET);
112 if (bytes > jf->jf_pos)
115 fseeko(jf->jf_fp, jf->jf_pos, SEEK_SET);
116 if (fread(buf, bytes, 1, jf->jf_fp) == 1) {
126 jset(struct jfile *jf)
128 jf->jf_setpt = jf->jf_pos;
132 jreturn(struct jfile *jf)
134 jf->jf_pos = jf->jf_setpt;
136 fseeko(jf->jf_fp, jf->jf_pos, SEEK_SET);
140 jflush(struct jfile *jf)