Imported from util-linux-2.12a tarball.

1 files changed, 53 insertions, 31 deletions

diff --git a/mount/losetup.8 b/mount/losetup.8
index d364f4f1e..9a42d70a0 100644
--- a/mount/losetup.8
+++ b/mount/losetup.8
@@ -1,15 +1,18 @@
-.TH LOSETUP 8 "Nov 24 1993" "Linux" "MAINTENANCE COMMANDS"
+.TH LOSETUP 8 "2003-07-01" "Linux" "MAINTENANCE COMMANDS"
 .SH NAME
 losetup \- set up and control loop devices
 .SH SYNOPSIS
 .ad l
 .B losetup
 [
-.B \-e
+.RB [ \-e | \-E ]
 .I encryption
 ] [
 .B \-o
 .I offset
+] [
+.B \-p
+.I pfd
 ]
 .I loop_device file
 .br
@@ -25,27 +28,41 @@ is used to associate loop devices with regular files or block devices,
 to detach loop devices and to query the status of a loop device. If only the
 \fIloop_device\fP argument is given, the status of the corresponding loop
 device is shown.
+
+.SS "Encryption"
+It is possible to specify transfer functions (for encryption/decryption
+or other purposes) using one of the
+.B \-E
+and
+.B \-e
+options.
+There are two mechanisms to specify the desired encryption: by number
+and by name. If an encryption is specified by number then one
+has to make sure that the Linux kernel knows about the encryption with that
+number, probably by patching the kernel. Standard numbers that are
+always present are 0 (no encryption) and 1 (XOR encryption).
+When the cryptoloop module is loaded (or compiled in), it uses number 18.
+This cryptoloop module wil take the name of an arbitrary encryption type
+and finds the module that knows how to perform that encryption.
+(Thus, either one uses a number different from 18 with the
+.B \-E
+option, or one uses a name with the
+.B \-e
+option.)
 .SH OPTIONS
 .IP \fB\-d\fP
-detach the file or device associated with the specified loop device.
-.IP "\fB\-e \fIencryption\fP"
-.RS
-enable data encryption. The following keywords are recognized:
-.IP \fBNONE\fP
-use no encryption (default).
-.PD 0
-.IP \fBXOR\fP
-use a simple XOR encryption.
-.IP \fBDES\fP
-use DES encryption. DES encryption is only available if the optional
-DES package has been added to the kernel. DES encryption uses an additional
-start value that is used to protect passwords against dictionary
-attacks.
-.PD
-.RE
+Detach the file or device associated with the specified loop device.
+.IP "\fB\-E \fIencryption_type\fP"
+Enable data encryption with specified number.
+.IP "\fB\-e \fIencryption_name\fP"
+Enable data encryption with specified name.
 .IP "\fB\-o \fIoffset\fP"
-the data start is moved \fIoffset\fP bytes into the specified file or
+The data start is moved \fIoffset\fP bytes into the specified file or
 device.
+.IP "\fB\-p \fInum\fP"
+Read the passphrase from file descriptor with number
+.I num
+instead of from the terminal.
 .SH RETURN VALUE
 .B losetup
 returns 0 on success, nonzero on failure. When
@@ -57,7 +74,7 @@ from determining the status of the device.
 
 .SH FILES
 .nf
-/dev/loop0,/dev/loop1,...   loop devices (major=7)
+/dev/loop0, /dev/loop1, ...   loop devices (major=7)
 .fi
 .SH EXAMPLE
 If you are using the loadable module you must have the module loaded
@@ -65,18 +82,23 @@ first with the command
 .IP
 # insmod loop.o
 .LP
+Maybe also encryption modules are needed.
+.IP
+# insmod des.o
+# insmod cryptoloop.o
+.LP
 The following commands can be used as an example of using the loop device.
 .nf
 .IP
-dd if=/dev/zero of=/file bs=1k count=100
-losetup -e des /dev/loop0 /file
+# dd if=/dev/zero of=/file bs=1k count=100
+# losetup -e des /dev/loop0 /file
 Password:
 Init (up to 16 hex digits):
-mkfs -t ext2 /dev/loop0 100
-mount -t ext2 /dev/loop0 /mnt
+# mkfs -t ext2 /dev/loop0 100
+# mount -t ext2 /dev/loop0 /mnt
  ...
-umount /dev/loop0
-losetup -d /dev/loop0
+# umount /dev/loop0
+# losetup -d /dev/loop0
 .fi
 .LP
 If you are using the loadable module you may remove the module with
@@ -87,8 +109,8 @@ the command
 .fi
 .SH RESTRICTION
 DES encryption is painfully slow. On the other hand, XOR is terribly weak.
-.SH AUTHORS
-.nf
-Original version: Theodore Ts'o <tytso@athena.mit.edu>
-Original DES by: Eric Young <eay@psych.psy.uq.oz.au>
-.fi
+.\" .SH AUTHORS
+.\" .nf
+.\" Original version: Theodore Ts'o <tytso@athena.mit.edu>
+.\" Original DES by: Eric Young <eay@psych.psy.uq.oz.au>
+.\" .fi