*)
open Unix
+open ExtList
+open ExtString
open Printf
open Int63.Operators
type output = File of string | Dir of string
type extcompress = BZip2 | GZip | External of string
+let max_disks = 32
+let max_image_name = 256
+
let rec main () =
(* Program name changes behaviour. *)
let compressing =
)
);
+ (* Write the main header. *)
+ write_header machine.Diskimage.m_disks;
+
(* Iterate over the disks. *)
- List.iter (
- fun { Diskimage.d_name = name; d_dev = disk } ->
+ List.iteri (
+ fun disknum { Diskimage.d_name = name; d_dev = disk } ->
let blocksize = disk#blocksize in
let size = disk#size in (* Size in bytes. *)
let nr_blocks = size /^ blocksize in (* Number of disk sectors. *)
in
(* Look up owners for each sector in turn. *)
- let rec loop blk =
- if blk < nr_blocks then (
- (* The current sector (blk) is either free or not free. Look
- * for a stretch of sectors which are the same.
+ let rec loop start_blk =
+ if start_blk < nr_blocks then (
+ (* The current sector (start_blk) is either free or not free.
+ * Look for a stretch of sectors which are the same.
*)
- let current_free = block_is_free blk in
+ let current_free = block_is_free start_blk in
let rec find_end blk =
if blk < nr_blocks then (
if block_is_free blk = current_free then
) else
nr_blocks (* End of the disk image. *)
in
- let end_blk = find_end (Int63.succ blk) in
+ let end_blk = find_end (Int63.succ start_blk) in
+
+ let len_blks = end_blk -^ start_blk in
- (* Current stretch is from blk .. end_blk-1. *)
+ let start_offset = start_blk *^ blocksize in
+ let len_bytes = len_blks *^ blocksize in
+
+ (* Current stretch is from start_blk .. end_blk-1. *)
if !Diskimage.debug then
- eprintf " %s stretch %s to %s-1 (%s bytes)\n"
+ eprintf " %s stretch %s to %s-1 (%s bytes)\n%!"
(if current_free then "free" else "used")
- (Int63.to_string blk) (Int63.to_string end_blk)
- (Int63.to_string ((end_blk-^blk) *^ blocksize));
-
+ (Int63.to_string start_blk) (Int63.to_string end_blk)
+ (Int63.to_string (len_blks *^ blocksize));
+ (* Write the stretch to stdout. *)
+ write_stretch_header disknum current_free start_offset len_bytes;
+ (* Write the data (note: we only need to write it if
+ * it's not marked as free!).
+ *)
+ if not current_free then write_stretch disk start_offset len_bytes;
loop end_blk
)
in
loop ~^0
- ) machine.Diskimage.m_disks
-
-
-
-
-
-
-
-
-
-
+ ) machine.Diskimage.m_disks;
+ write_trailer ()
and go_decompress ?output extcompress args =
(* Read the input, which may be a single named file, or a series of
-(*
(* Since we have the wonderful pa_bitmatch, might as well use it to
* define a robust binary format for the compressed files.
+ *
+ * These functions are in matched pairs "write_foo" / "read_foo" so
+ * you can check that the write and read protocols agree.
*)
-and write_header ... =
- let bs = BITSTRING {
- 0xD152 : 16; 0x01 : 8; 0x00 : 8; (* file magic, version 1.0 *)
- nr_disks : 8; (* number of disks being packed *)
-
-
-
+and write_header disks =
+ let nr_disks = List.length disks in
+ assert (nr_disks > 0);
- } in
-
+ (* Don't allow large numbers of disks. *)
+ if nr_disks > max_disks then (
+ eprintf (f_"diskzip: maximum number of disk images is limited by the current image format to %d") nr_disks;
+ exit 2
+ );
+ let names = List.map (
+ fun { Diskimage.d_name = name } ->
+ let name =
+ try
+ let i = 1 + String.rindex name '/' in
+ String.sub name i (String.length name - i)
+ with
+ Invalid_string | Not_found -> name in
+
+ let contains_dotdot =
+ try ignore (String.find name ".."); true
+ with Invalid_string | Not_found -> false in
+ if contains_dotdot then (
+ prerr_endline (s_"diskzip: disk image names cannot contain \"..\"");
+ exit 2
+ );
+
+ (* Don't allow very long names. *)
+ if String.length name > max_image_name then (
+ eprintf (f_"diskzip: maximum length of disk image name is limited by the current image format to %d bytes") max_image_name;
+ exit 2
+ );
+
+ name
+ ) disks in
+
+ (* Header followed by names. *)
+ let header =
+ let header =
+ let bs = BITSTRING {
+ 0xD152 : 16; 0x01 : 8; 0x00 : 8; (* file magic, version 1.0 *)
+ nr_disks : 8 (* number of disks being packed *)
+ } in
+ let len = Bitmatch.bitstring_length bs in
+ assert (len land 7 = 0);
+ Bitmatch.string_of_bitstring bs in
+ let names = List.map (
+ fun name ->
+ let bs =
+ BITSTRING {
+ String.length name : 16;
+ name : -1 : string
+ } in
+ let len = Bitmatch.bitstring_length bs in
+ assert (len land 7 = 0);
+ Bitmatch.string_of_bitstring bs
+ ) names in
+
+ (* Construct the final header. *)
+ header ^ String.concat "" names in
+
+ ignore (write stdout header 0 (String.length header))
+
+(*
and read_header () =
(* Diskzip headers are limited to overall max size of 1024 bytes. *)
let bs = Bitmatch.bitstring_of_file_descr_max stdin 1024 in
exit 1
*)
+and write_stretch_header disknum free start_offset len_bytes =
+ let start_offset = Int63.to_int64 start_offset in
+ let len_bytes = Int63.to_int64 len_bytes in
+
+ let bs = BITSTRING {
+ (* Stretch header magic. Allows us to find synchronization errors. *)
+ 0xD1525555_l : 32;
+ free : 1; 0 : 7; (* Flags. *)
+ disknum : 8; (* Disk number. *)
+ start_offset : 64; (* Start offset in disk image (bytes)*)
+ len_bytes : 64 (* Length in bytes. *)
+ } in
+
+ let str = Bitmatch.string_of_bitstring bs in
+ ignore (write stdout str 0 (String.length str))
+
+and write_stretch dev start_offset len_bytes =
+ (* Limit size of blocks that we write, since some implementations
+ * of device class cannot handle large blocks. In any case I tested
+ * this and writing large blocks isn't any faster.
+ *)
+ let blocksize = ~^65536 in
+ let rec loop offset len =
+ if len > ~^0 then (
+ let n = min blocksize len in
+ ignore (write stdout (dev#read offset n) 0 (Int63.to_int n));
+ loop (offset+^n) (len-^n)
+ )
+ in
+ loop start_offset len_bytes
+
+and write_trailer () =
+ let bs = BITSTRING {
+ 0xD152FFFF_l : 32
+ } in
+ let str = Bitmatch.string_of_bitstring bs in
+ ignore (write stdout str 0 (String.length str))
+
let () = main ()
git.annexia.org / virt-df.git / commitdiff