1 files changed, 47 insertions, 12 deletions

diff --git a/src/with-btrfs-seed b/src/with-btrfs-seed
index 9f0147e..f78417b 100755
--- a/src/with-btrfs-seed
+++ b/src/with-btrfs-seed
@@ -2,10 +2,13 @@
 
 usage()
 {
-    print >&2 <<EOF
-usage: $0 <file.iso> [command] [args ...]
+    cat >&2 <<EOF
+usage: $0 [options] <file.iso> [command] [args ...]
 
-  default command is bash
+    options:
+        --resize <size>
+        --btrfs-options <mount options>     (default: compress)
+        --no-chroot
 EOF
     exit $1
 }
@@ -29,7 +32,6 @@ have_root()
 main()
 {
     have_root || error "you are not root"
-    [ $# = 0 ] && usage 0
 
     iso_file=$1
     shift
@@ -37,17 +39,31 @@ main()
     iso_file_clone=${iso_file}.clone.tmp
     mountpoint=${iso_file%.iso}.mnt.tmp
 
-    [ -f "$iso_file" ]                                || error "not a file: $iso_file"
-    [ ! -f "$iso_file_clone" ]                        || error "refusing to clobber existing file: $iso_file_clone"
-    [ -d "$mountpoint" ] || mkdir "$mountpoint"       || error "could not create directory $mountpoint"
-    ! mountpoint -q "$mountpoint"                     || error "directory is already a mountpoint: $mountpoint"
+    [ -f "$iso_file" ]                                        || error "not a file: $iso_file"
+    [ ! -f "$iso_file_clone" ]                                || error "refusing to clobber existing file: $iso_file_clone"
+    [ -d "$mountpoint" ] || mkdir "$mountpoint"               || error "could not create directory $mountpoint"
+    ! mountpoint -q "$mountpoint"                             || error "directory is already a mountpoint: $mountpoint"
 
-    cp --reflink=always "$iso_file" "$iso_file_clone" || error "cp failed"
+    cp --reflink=always "$iso_file" "$iso_file_clone"         || error "cp failed"
     trap 'rm -f "$iso_file_clone"' EXIT
-    btrfstune -f -S 0 "$iso_file_clone" 2>/dev/null   || error "btrfstune failed"
-    mount -o rw,loop "$iso_file_clone" "$mountpoint"  || error "failed to mount $iso_file"
 
-    chroot "$mountpoint" "$@"
+    if [ "$RESIZE" ]; then
+        truncate --size="$RESIZE" "$iso_file_clone"           || error "failed to resize image with truncate"
+    fi
+
+    btrfstune -f -S 0 "$iso_file_clone" 2>/dev/null           || error "btrfstune failed"
+    mount_options=rw,loop${BTRFS_OPTIONS:+,$BTRFS_OPTIONS}
+    mount -o "$mount_options" "$iso_file_clone" "$mountpoint" || error "failed to mount $iso_file"
+
+    if [ "$RESIZE" ]; then
+        btrfs filesystem resize max "$mountpoint"             || error "btrfs filesystem resize"
+    fi
+
+    if [ "$CHROOT" ]; then
+        chroot "$mountpoint" "$@"
+    else
+        "$@" "$mountpoint"
+    fi
     result=$?
     umount "$mountpoint" || warning "umount $mountpoint failed!  You had better do something about it"
     rmdir "$mountpoint"
@@ -60,4 +76,23 @@ main()
     fi
 }
 
+[ $# = 0 ] && usage 0
+
+CHROOT=y
+eval set -- "$(getopt -o '' --long no-chroot,resize:,fork:,btrfs-options: -n "$0" -- "$@")" || error 'getopt error'
+while [ $# -gt 0 ]; do
+    case "$1" in
+        --) shift; break;;
+        --resize) RESIZE=$2; shift 2;;
+        --fork) FORK=$2; shift 2;;
+        --btrfs-options) BTRFS_OPTIONS=$2; shift 2;;
+        --no-chroot) CHROOT=; shift;;
+        *) error "unrecognized option: $1"
+    esac
+done
+
+: ${BTRFS_OPTIONS:=compress}
+
+[ "$FORK" ] && error "unimplemented option: --fork"
+
 main "$@"