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cycle.c
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cycle.c
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/*
* Copyright (c) 2008 The DragonFly Project. All rights reserved.
*
* This code is derived from software contributed to The DragonFly Project
* by Matthew Dillon <dillon@backplane.com>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
* 3. Neither the name of The DragonFly Project nor the names of its
* contributors may be used to endorse or promote products derived
* from this software without specific, prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $DragonFly: src/sbin/hammer/cycle.c,v 1.5 2008/07/07 00:27:22 dillon Exp $
*/
#include "hammer.h"
void
hammer_get_cycle(hammer_base_elm_t base, hammer_tid_t *extra)
{
struct stat st;
int fd;
if (CyclePath && (fd = open(CyclePath, O_RDONLY)) >= 0) {
if (fstat(fd, &st) < 0) {
fprintf(stderr, "cycle-file %s: cannot stat\n",
CyclePath);
close(fd);
return;
}
if (st.st_size < sizeof(*base)) {
fprintf(stderr, "cycle-file %s: clearing old version\n",
CyclePath);
close(fd);
remove(CyclePath);
return;
}
if (read(fd, base, sizeof(*base)) != sizeof(*base)) {
fprintf(stderr, "cycle-file %s: read failed %s\n",
CyclePath, strerror(errno));
return;
}
if (extra) {
if (read(fd, extra, sizeof(*extra)) != sizeof(*extra)) {
fprintf(stderr, "cycle-file %s: Warning, malformed\n",
CyclePath);
}
}
close(fd);
}
/* ok if the file does not exist */
}
void
hammer_set_cycle(hammer_base_elm_t base, hammer_tid_t extra)
{
int fd;
if ((fd = open(CyclePath, O_RDWR|O_CREAT|O_TRUNC, 0666)) >= 0) {
write(fd, base, sizeof(*base));
write(fd, &extra, sizeof(extra));
close(fd);
} else {
fprintf(stderr, "Warning: Unable to write to %s: %s\n",
CyclePath, strerror(errno));
}
}
void
hammer_reset_cycle(void)
{
remove(CyclePath);
}