sbin/hammer/cycle.c

   1 /*
   2  * Copyright (c) 2008 The DragonFly Project.  All rights reserved.
   3  *
   4  * This code is derived from software contributed to The DragonFly Project
   5  * by Matthew Dillon <dillon@backplane.com>
   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  *
  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
  16  *    distribution.
  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.
  20  *
  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
  32  * SUCH DAMAGE.
  33  *
  34  * $DragonFly: src/sbin/hammer/cycle.c,v 1.5 2008/07/07 00:27:22 dillon Exp $
  35  */
  36
  37 #include "hammer.h"
  38
  39 void
  40 hammer_get_cycle(hammer_base_elm_t base, hammer_tid_t *extra)
  41 {
  42         struct stat st;
  43         int fd;
  44
  45         if (CyclePath && (fd = open(CyclePath, O_RDONLY)) >= 0) {
  46                 if (fstat(fd, &st) < 0) {
  47                         fprintf(stderr, "cycle-file %s: cannot stat\n",
  48                                 CyclePath);
  49                         close(fd);
  50                         return;
  51                 }
  52                 if (st.st_size < (off_t)sizeof(*base)) {
  53                         fprintf(stderr, "cycle-file %s: clearing old version\n",
  54                                 CyclePath);
  55                         close(fd);
  56                         remove(CyclePath);
  57                         return;
  58                 }
  59                 if (read(fd, base, sizeof(*base)) != sizeof(*base)) {
  60                         fprintf(stderr, "cycle-file %s: read failed %s\n",
  61                                 CyclePath, strerror(errno));
  62                         return;
  63                 }
  64                 if (extra)
  65                         if (read(fd, extra, sizeof(*extra)) != sizeof(*extra))
  66                                 fprintf(stderr, "cycle-file %s: Warning, malformed\n",
  67                                         CyclePath);
  68                 close(fd);
  69         }
  70         /* ok if the file does not exist */
  71 }
  72
  73 void
  74 hammer_set_cycle(hammer_base_elm_t base, hammer_tid_t extra)
  75 {
  76         int fd;
  77
  78         if ((fd = open(CyclePath, O_RDWR|O_CREAT|O_TRUNC, 0666)) >= 0) {
  79                 write(fd, base, sizeof(*base));
  80                 write(fd, &extra, sizeof(extra));
  81                 close(fd);
  82         } else {
  83                 fprintf(stderr, "Warning: Unable to write to %s: %s\n",
  84                         CyclePath, strerror(errno));
  85         }
  86 }
  87
  88 void
  89 hammer_reset_cycle(void)
  90 {
  91         remove(CyclePath);
  92 }
  93