mount_root.c

   1 /*
   2  * Copyright (C) 2014 John Crispin <blogic@openwrt.org>
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU Lesser General Public License version 2.1
   6  * as published by the Free Software Foundation
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11  * GNU General Public License for more details.
  12  */
  13
  14 #include <sys/mount.h>
  15 #include <stdio.h>
  16 #include <stdlib.h>
  17
  18 #include <libubox/ulog.h>
  19
  20 #include "libfstools/libfstools.h"
  21 #include "libfstools/volume.h"
  22
  23 /*
  24  * Called in the early (PREINIT) stage, when we immediately need some writable
  25  * filesystem.
  26  */
  27 static int
  28 start(int argc, char *argv[1])
  29 {
  30         struct volume *root;
  31         struct volume *data = volume_find("rootfs_data");
  32
  33         if (!getenv("PREINIT"))
  34                 return -1;
  35
  36         if (!data) {
  37                 root = volume_find("rootfs");
  38                 volume_init(root);
  39                 ULOG_NOTE("mounting /dev/root\n");
  40                 mount("/dev/root", "/", NULL, MS_NOATIME | MS_REMOUNT, 0);
  41         }
  42
  43         /*
  44          * Before trying to mount and use "rootfs_data" let's check if there is
  45          * extroot configured. Following call will handle reading config from
  46          * the "rootfs_data" on its own.
  47          */
  48         extroot_prefix = "";
  49         if (!mount_extroot()) {
  50                 ULOG_NOTE("switched to extroot\n");
  51                 return 0;
  52         }
  53
  54         /* There isn't extroot, so just try to mount "rootfs_data" */
  55         switch (volume_identify(data)) {
  56         case FS_NONE:
  57         case FS_DEADCODE:
  58                 /*
  59                  * Filesystem isn't ready yet and we are in the preinit, so we
  60                  * can't afford waiting for it. Use tmpfs for now and handle it
  61                  * properly in the "done" call.
  62                  */
  63                 return ramoverlay();
  64
  65         case FS_JFFS2:
  66         case FS_UBIFS:
  67                 mount_overlay(data);
  68                 break;
  69
  70         case FS_SNAPSHOT:
  71                 mount_snapshot(data);
  72                 break;
  73         }
  74
  75         return 0;
  76 }
  77
  78 static int
  79 stop(int argc, char *argv[1])
  80 {
  81         if (!getenv("SHUTDOWN"))
  82                 return -1;
  83
  84         return 0;
  85 }
  86
  87 /*
  88  * Called at the end of init, it can wait for filesystem if needed.
  89  */
  90 static int
  91 done(int argc, char *argv[1])
  92 {
  93         struct volume *v = volume_find("rootfs_data");
  94
  95         if (!v)
  96                 return -1;
  97
  98         switch (volume_identify(v)) {
  99         case FS_NONE:
 100         case FS_DEADCODE:
 101                 return jffs2_switch(v);
 102         }
 103
 104         return 0;
 105 }
 106
 107 int main(int argc, char **argv)
 108 {
 109         if (argc < 2)
 110                 return start(argc, argv);
 111         if (!strcmp(argv[1], "stop"))
 112                 return stop(argc, argv);
 113         if (!strcmp(argv[1], "done"))
 114                 return done(argc, argv);
 115         return -1;
 116 }