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 1.3 2005/07/05 00:26:03 dillon Exp $
40 * Open a journal for directional scanning
43 jopen_stream(const char *path, enum jdirection jdir)
48 if ((fp = fopen(path, "r")) == NULL)
50 if ((jf = jopen_fp(fp, jdir)) == NULL)
56 jopen_fp(FILE *fp, enum jdirection jdir)
60 jf = malloc(sizeof(struct jfile));
61 bzero(jf, sizeof(struct jfile));
63 jf->jf_direction = jdir;
65 if (jdir == JF_BACKWARDS) {
66 fseeko(jf->jf_fp, 0L, SEEK_END);
67 jf->jf_pos = ftello(jf->jf_fp);
73 * Close a previously opened journal, clean up any side allocations.
76 jclose_stream(struct jfile *jf)
82 while ((jd = jf->jf_saved) != NULL) {
83 jf->jf_saved = jd->jd_next;
90 * Align us to the next 16 byte boundary. If scanning forwards we align
91 * forwards if not already aligned. If scanning backwards we align
92 * backwards if not already aligned.
95 jalign(struct jfile *jf)
97 if (jf->jf_direction == JF_FORWARDS) {
98 jf->jf_pos = (jf->jf_pos + 15) & ~15;
99 fseeko(jf->jf_fp, jf->jf_pos, SEEK_SET);
101 jf->jf_pos = jf->jf_pos & ~15;
106 * Read data from a journal forwards or backwards. Note that the file
107 * pointer's actual seek position does not match jf_pos in the reverse
108 * scan case. Callers should never access jf_fp directly.
111 jread(struct jfile *jf, void *buf, int bytes)
113 if (jf->jf_direction == JF_FORWARDS) {
114 if (fread(buf, bytes, 1, jf->jf_fp) == 1) {
118 fseeko(jf->jf_fp, jf->jf_pos, SEEK_SET);
119 return (errno ? errno : ENOENT);
122 if (bytes > jf->jf_pos)
125 fseeko(jf->jf_fp, jf->jf_pos, SEEK_SET);
126 if (fread(buf, bytes, 1, jf->jf_fp) == 1) {
136 jset(struct jfile *jf)
138 jf->jf_setpt = jf->jf_pos;
142 jreturn(struct jfile *jf)
144 jf->jf_pos = jf->jf_setpt;
146 fseeko(jf->jf_fp, jf->jf_pos, SEEK_SET);
150 jflush(struct jfile *jf)