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 1.7 2008/07/10 18:47:22 mneumann Exp $
  35  */
  36
  37 #include "hammer.h"
  38 #include <sys/param.h>
  39 #include <sys/mount.h>
  40 #include <sys/types.h>
  41 #include <sys/stat.h>
  42 #include <unistd.h>
  43 #include <string.h>
  44 #include <time.h>
  45
  46 #define DEFAULT_SNAPSHOT_NAME "snap-%Y%m%d-%H%M"
  47
  48 static void snapshot_usage(int exit_code);
  49
  50 /*
  51  * snapshot <softlink-dir-in-filesystem>
  52  * snapshot <filesystem> <softlink-dir>
  53  */
  54 void
  55 hammer_cmd_snapshot(char **av, int ac)
  56 {
  57         const char *filesystem;
  58         const char *softlink_dir;
  59         char *softlink_fmt;
  60         struct statfs buf;
  61         struct stat st;
  62         struct hammer_ioc_synctid synctid;
  63         char *from;
  64         char *to;
  65
  66         if (ac == 1) {
  67                 filesystem = NULL;
  68                 softlink_dir = av[0];
  69         } else if (ac == 2) {
  70                 filesystem = av[0];
  71                 softlink_dir = av[1];
  72         } else {
  73                 snapshot_usage(1);
  74         }
  75
  76         if (stat(softlink_dir, &st) == 0) {
  77                 if (!S_ISDIR(st.st_mode))
  78                         err(2, "File %s already exists", softlink_dir);
  79
  80                 if (filesystem == NULL) {
  81                         if (statfs(softlink_dir, &buf) != 0) {
  82                                 err(2, "Unable to determine filesystem of %s",
  83                                     softlink_dir);
  84                         }
  85                         filesystem = buf.f_mntonname;
  86                 }
  87
  88                 softlink_fmt = malloc(strlen(softlink_dir) + 1 + 1 +
  89                                       sizeof(DEFAULT_SNAPSHOT_NAME));
  90                 if (softlink_fmt == NULL)
  91                         err(2, "Failed to allocate string");
  92
  93                 strcpy(softlink_fmt, softlink_dir);
  94                 if (softlink_fmt[strlen(softlink_fmt)-1] != '/')
  95                         strcat(softlink_fmt, "/");
  96                 strcat(softlink_fmt, DEFAULT_SNAPSHOT_NAME);
  97         } else {
  98                 softlink_fmt = strdup(softlink_dir);
  99
 100                 if (filesystem == NULL) {
 101                         /*
 102                          * strip-off last '/path' segment to get the softlink
 103                          * directory, which we need to determine the filesystem
 104                          * we are on.
 105                          */
 106                         char *pos = strrchr(softlink_fmt, '/');
 107                         if (pos != NULL)
 108                                 *pos = '\0';
 109
 110                         if (stat(softlink_fmt, &st) != 0 ||
 111                             !S_ISDIR(st.st_mode)) {
 112                                 err(2, "Unable to determine softlink dir %s",
 113                                     softlink_fmt);
 114                         }
 115                         if (statfs(softlink_fmt, &buf) != 0) {
 116                                 err(2, "Unable to determine filesystem of %s",
 117                                     softlink_fmt);
 118                         }
 119                         filesystem = buf.f_mntonname;
 120
 121                         /* restore '/' */
 122                         if (pos != NULL)
 123                                 *pos = '/';
 124                 }
 125         }
 126
 127         /*
 128          * Synctid
 129          */
 130         bzero(&synctid, sizeof(synctid));
 131         synctid.op = HAMMER_SYNCTID_SYNC2;
 132         int fd = open(filesystem, O_RDONLY);
 133         if (fd < 0)
 134                 err(2, "Unable to open %s", filesystem);
 135         if (ioctl(fd, HAMMERIOC_SYNCTID, &synctid) < 0)
 136                 err(2, "Synctid %s failed", filesystem);
 137         close(fd);
 138
 139         asprintf(&from, "%s/@@0x%016llx", filesystem, synctid.tid);
 140         if (from == NULL)
 141                 err(2, "Couldn't generate string");
 142
 143         int sz = strlen(softlink_fmt) + 50;
 144         to = malloc(sz);
 145         if (to == NULL)
 146                 err(2, "Failed to allocate string");
 147
 148         time_t t = time(NULL);
 149         if (strftime(to, sz, softlink_fmt, localtime(&t)) == 0)
 150                 err(2, "String buffer too small");
 151
 152         if (symlink(from, to) != 0)
 153                 err(2, "Unable to symlink %s to %s", from, to);
 154
 155         printf("%s\n", to);
 156
 157         free(softlink_fmt);
 158         free(from);
 159         free(to);
 160 }
 161
 162 static
 163 void
 164 snapshot_usage(int exit_code)
 165 {
 166         fprintf(stderr, "hammer snapshot <snapshot-dir-in-filesystem>\n");
 167         fprintf(stderr, "hammer snapshot <filesystem> <snapshot-dir>\n");
 168         exit(exit_code);
 169 }