execfuse/autosshfs/readdir

   1 #!/bin/bash
   2
   3 # Usage:
   4 # execfuse ./autosshfs ~/mnt/ssh -o fsname=autosshfs.$USER,allow_root
   5
   6 # You have to set this in ~/.ssh/config:
   7 #   ControlMaster auto
   8 #   ControlPath ~/.ssh/ctrl/%r@%n(%h):%p.sock
   9
  10 shopt -s nullglob
  11
  12 operation=${0##*/}
  13
  14 connections_subdir=${EXECFUSE_MOUNTPOINT##*/}
  15 attr_parentdir="ino=1 mode=drwxr-xr-x nlink=2 uid=0 gid=0 rdev=0 size=0 blksize=512 blocks=2 atime=0 mtime=0 ctime=0"
  16 attr_rootdir="ino=1 mode=drwxr-xr-x nlink=2 uid=$UID gid=0 rdev=0 size=0 blksize=512 blocks=2 atime=0 mtime=0 ctime=0"
  17 attr_entry="ino=1 mode=drwx------ nlink=1 uid=$UID gid=0 rdev=0 size=0 blksize=512 blocks=2 atime=0 mtime=0 ctime=0"
  18 attr_alias="ino=1 mode=drwx------ nlink=1 uid=$UID gid=0 rdev=0 size=0 blksize=512 blocks=2 atime=0 mtime=0 ctime=0"
  19
  20
  21 declare -A Conn
  22 read_connections()
  23 {
  24         if [ ${#Conn[@]} = 0 ]
  25         then
  26                 reread_connections
  27         fi
  28 }
  29 reread_connections()
  30 {
  31         local file name
  32         Conn=()
  33         for file in ~/.ssh/ctrl/*.sock
  34         do
  35                 name=${file##*/}
  36                 name=${name%.*}
  37                 Conn[$name]=1
  38         done
  39 }
  40 get_host_alias()
  41 {
  42         if [[ $1 =~ @(.+)\( ]]
  43         then
  44                 echo "${BASH_REMATCH[1]}"
  45         fi
  46 }
  47
  48 lock_nb()
  49 {
  50         _lock -n "$@"
  51 }
  52
  53 lock()
  54 {
  55         _lock '' "$@"
  56 }
  57
  58 _lock()
  59 {
  60         local dir="/tmp/autosshfs.$USER"
  61         local flag=$1
  62         shift
  63         local conn=$1
  64         shift
  65         mkdir -p -m 0700 "$dir"
  66         flock -x $flag "$dir/$conn" "$@"
  67 }
  68
  69 mount_sshfs_async()
  70 {
  71         local conn=$1
  72         local port=$2
  73         local user=$3
  74         local host=$4
  75         local hostname=$5
  76         local target=$6
  77         lock_nb "mount+$conn" setsid sshfs -o Port=$port,ControlMaster=no,transform_symlinks,reconnect,Hostname="$hostname" "$user@$host:/" "$target" >/dev/null 2>&1 &
  78         # -o sftp_server='sudo /usr/lib/openssh/sftp-server'
  79 }
  80
  81
  82 if [ "$operation" = getattr ]
  83 then
  84         if [ "$1" = / ]
  85         then
  86                 printf "$attr_rootdir"
  87                 exit 0
  88         else
  89                 read_connections
  90                 for conn in "${!Conn[@]}"
  91                 do
  92                         if [ "$1" = "/$conn" ]
  93                         then
  94                                 printf "$attr_entry"
  95                                 exit 0
  96                         else
  97                                 hostalias=`get_host_alias "$conn"`
  98                                 if [ "$1" = "/$hostalias" ]
  99                                 then
 100                                         printf "$attr_alias"
 101                                         exit 0
 102                                 fi
 103                         fi
 104                 done
 105                 exit 1
 106         fi
 107
 108 elif [ "$operation" = readdir ]
 109 then
 110         # first umount all dead connections
 111         cat /proc/mounts |\
 112         while read -r dev mp rest
 113         do
 114                 if [[ $mp =~ ^(.+)/([^/]+)$ ]]
 115                 then
 116                         dir=${BASH_REMATCH[1]}
 117                         subdir=${BASH_REMATCH[2]}
 118                         if [ "$dir" = "$EXECFUSE_MOUNTPOINT" ]
 119                         then
 120                                 read_connections
 121                                 if [ -z "${Conn[$subdir]}" ]
 122                                 then
 123                                         lock_nb "umount+$subdir" setsid fusermount -u -z "$mp" >/dev/null 2>&1 &
 124                                 fi
 125                         fi
 126                 fi
 127         done
 128
 129         # list directories to each ssh connection when listing the root directory
 130         if [ "$1" = / ]
 131         then
 132                 printf "$attr_rootdir .\0"
 133                 printf "$attr_parentdir ..\0"
 134
 135                 read_connections
 136                 for conn in "${!Conn[@]}"
 137                 do
 138                         printf "$attr_entry %s\0" "$conn"
 139                         hostalias=`get_host_alias "$conn"`
 140                         ln -snf "$connections_subdir/$conn" "$EXECFUSE_MOUNTPOINT/../$hostalias"
 141                 done
 142
 143                 exit 0
 144
 145         # when listing a subdirectory, mount the corresponding sshfs under it.
 146         # and return async, so you need to chdir to the directory again to get the actual content.
 147         else
 148                 printf "$attr_entry .\0"
 149                 printf "$attr_rootdir ..\0"
 150
 151                 read_connections
 152                 for conn in "${!Conn[@]}"
 153                 do
 154                         if [ "/$conn" = "$1" ]
 155                         then
 156                                 if [[ $conn =~ ^([^@]+)@([^\(]+)\(([^\)]+)\):([0-9]+) ]]
 157                                 then
 158                                         user=${BASH_REMATCH[1]}
 159                                         host=${BASH_REMATCH[2]}
 160                                         hostname=${BASH_REMATCH[3]}
 161                                         port=${BASH_REMATCH[4]}
 162
 163                                         mount_sshfs_async "$conn" "$port" "$user" "$host" "$hostname" "$EXECFUSE_MOUNTPOINT$1"
 164                                         exit 0
 165                                 fi
 166                         fi
 167                 done
 168
 169                 exit 1
 170         fi
 171 fi
 172