sbin/hammer/cmd_snapshot.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/cmd_snapshot.c,v 1.4 2008/06/26 16:13:43 mneumann Exp $
  35  */
  36
  37 #include "hammer.h"
  38 #include <sys/param.h>
  39 #include <sys/mount.h>
  40 #include <unistd.h>
  41 #include <string.h>
  42 #include <time.h>
  43
  44 static void snapshot_usage(int exit_code);
  45
  46 /*
  47  * snapshot <softlink-dir-in-filesystem>
  48  * snapshot <filesystem> <softlink-dir>
  49  */
  50 void
  51 hammer_cmd_snapshot(char **av, int ac)
  52 {
  53         char *softlink_fmt;
  54         const char *filesystem;
  55         struct statfs buf;
  56         struct hammer_ioc_synctid synctid;
  57         int fd;
  58         char *from;
  59         char *to;
  60
  61         if (ac == 1) {
  62                 filesystem = NULL;
  63                 softlink_fmt = av[0];
  64         }
  65         else if (ac == 2) {
  66                 filesystem = av[0];
  67                 softlink_fmt = av[1];
  68         }
  69         else {
  70                 snapshot_usage(1);
  71         }
  72
  73         if (filesystem == NULL) {
  74                 /*
  75                  * Determine softlink directory required to
  76                  * determine the filesystem we are on.
  77                  */
  78                 char *softlink_dir = strdup(softlink_fmt);
  79                 fd = open(softlink_dir, O_RDONLY);
  80                 if (fd < 0) {
  81                         /* strip-off last '/path' segment */
  82                         char *pos = strrchr(softlink_dir, '/');
  83                         if (pos != NULL)
  84                                 *pos = '\0';
  85                         fd = open(softlink_dir, O_RDONLY);
  86                         if (fd < 0) {
  87                                 err(2, "Unable to determine softlink dir %s",
  88                                     softlink_dir);
  89                         }
  90                 }
  91                 close(fd);
  92
  93                 if (statfs(softlink_dir, &buf) != 0) {
  94                         err(2, "Unable to determine filesystem of %s",
  95                             softlink_dir);
  96                 }
  97                 filesystem = buf.f_mntonname;
  98                 free(softlink_dir);
  99         }
 100
 101         /*
 102          * Synctid
 103          */
 104         bzero(&synctid, sizeof(synctid));
 105         synctid.op = HAMMER_SYNCTID_SYNC2;
 106         fd = open(filesystem, O_RDONLY);
 107         if (fd < 0)
 108                 err(2, "Unable to open %s", filesystem);
 109         if (ioctl(fd, HAMMERIOC_SYNCTID, &synctid) < 0)
 110                 err(2, "Synctid %s failed", filesystem);
 111         close(fd);
 112
 113         asprintf(&from, "%s@@0x%016llx", filesystem, synctid.tid);
 114         if (from == NULL)
 115                 err(2, "Couldn't generate string");
 116
 117         int sz = strlen(softlink_fmt) + 50;
 118         to = malloc(sz);
 119         if (to == NULL)
 120                 err(2, "Failed to allocate string");
 121
 122         time_t t = time(NULL);
 123         if (strftime(to, sz, softlink_fmt, localtime(&t)) == 0)
 124                 err(2, "String buffer too small");
 125
 126         if (symlink(from, to) != 0)
 127                 err(2, "Unable to symlink %s to %s", from, to);
 128
 129         printf("%s\n", to);
 130
 131         free(from);
 132         free(to);
 133 }
 134
 135 static
 136 void
 137 snapshot_usage(int exit_code)
 138 {
 139         fprintf(stderr, "hammer snapshot <snapshot-dir-in-filesystem>\n");
 140         fprintf(stderr, "hammer snapshot <filesystem> <snapshot-dir>\n");
 141         exit(exit_code);
 142 }
 143