2 files changed, 121 insertions, 0 deletions

diff --git a/autofs.nix b/autofs.nix
new file mode 100644
index 00000000..f4a1059d
--- /dev/null
+++ b/autofs.nix
@@ -0,0 +1,120 @@
+{ config, lib, pkgs, ... }:
+
+with lib;
+
+let
+
+  cfg = config.services.autofs;
+
+  autoMaster = pkgs.writeText "auto.master" cfg.autoMaster;
+
+in
+
+{
+
+  ###### interface
+
+  options = {
+
+    services.autofs = {
+
+      enable = mkOption {
+        default = false;
+        description = "
+          Mount filesystems on demand. Unmount them automatically.
+          You may also be interested in afuese.
+        ";
+      };
+
+      autoMaster = mkOption {
+        example = literalExample ''
+          autoMaster = let
+            mapConf = pkgs.writeText "auto" '''
+             kernel    -ro,soft,intr       ftp.kernel.org:/pub/linux
+             boot      -fstype=ext2        :/dev/hda1
+             windoze   -fstype=smbfs       ://windoze/c
+             removable -fstype=ext2        :/dev/hdd
+             cd        -fstype=iso9660,ro  :/dev/hdc
+             floppy    -fstype=auto        :/dev/fd0
+             server    -rw,hard,intr       / -ro myserver.me.org:/ \
+                                           /usr myserver.me.org:/usr \
+                                           /home myserver.me.org:/home
+            ''';
+          in '''
+            /auto file:''${mapConf}
+          '''
+        '';
+        description = "
+          file contents of /etc/auto.master. See man auto.master
+          See man 5 auto.master and man 5 autofs.
+        ";
+      };
+
+      timeout = mkOption {
+        default = 600;
+        description = "Set the global minimum timeout, in seconds, until directories are unmounted";
+      };
+
+      debug = mkOption {
+        default = false;
+        description = "
+        pass -d and -7 to automount and write log to /var/log/autofs
+        ";
+      };
+
+    };
+
+  };
+
+
+  ###### implementation
+
+  config = mkIf cfg.enable {
+
+    environment.etc = singleton
+      { target = "auto.master";
+        source = pkgs.writeText "auto.master" cfg.autoMaster;
+      };
+
+    boot.kernelModules = [ "autofs4" ];
+
+    jobs.autofs =
+      { description = "Filesystem automounter";
+
+        startOn = "started network-interfaces";
+        stopOn = "stopping network-interfaces";
+
+        path = [ pkgs.nfs-utils pkgs.sshfsFuse ];
+
+        preStop =
+          ''
+            set -e; while :; do pkill -TERM automount; sleep 1; done
+          '';
+
+        # automount doesn't clean up when receiving SIGKILL.
+        # umount -l should unmount the directories recursively when they are no longer used
+        # It does, but traces are left in /etc/mtab. So unmount recursively..
+        postStop =
+          ''
+          PATH=${pkgs.gnused}/bin:${pkgs.coreutils}/bin
+          exec &> /tmp/logss
+          # double quote for sed:
+          escapeSpaces(){ sed 's/ /\\\\040/g'; }
+          unescapeSpaces(){ sed 's/\\040/ /g'; }
+          sed -n 's@^\s*\(\([^\\ ]\|\\ \)*\)\s.*@\1@p' ${autoMaster} | sed 's/[\\]//' | while read mountPoint; do
+            sed -n "s@[^ ]\+\s\+\($(echo "$mountPoint"| escapeSpaces)[^ ]*\).*@\1@p" /proc/mounts | sort -r | unescapeSpaces| while read smountP; do
+              ${pkgs.utillinux}/bin/umount -l "$smountP" || true
+            done
+          done
+          '';
+
+        script =
+          ''
+            ${if cfg.debug then "exec &> /var/log/autofs" else ""}
+            exec ${pkgs.autofs5}/sbin/automount ${if cfg.debug then "-d" else ""} -f -t ${builtins.toString cfg.timeout} "${autoMaster}" ${if cfg.debug then "-l7" else ""}
+          '';
+      };
+
+  };
+
+}
diff --git a/bragi.nix b/bragi.nix
index a65de32d..ce68c812 100644
--- a/bragi.nix
+++ b/bragi.nix
@@ -4,6 +4,7 @@
   imports =
     [
       ./bragi-hw.nix
+      ./autofs.nix
     ];
 
   boot.loader.grub.enable = true;