From 23b85230e7bf53881b265ef8bf03ec05ac5cefd2 Mon Sep 17 00:00:00 2001 From: Karel Zak Date: Thu, 22 Dec 2011 12:08:37 +0100 Subject: losetup: cleanup man page Signed-off-by: Karel Zak --- sys-utils/losetup.8 | 94 +++++++++++++++++++++-------------------------------- 1 file changed, 37 insertions(+), 57 deletions(-) (limited to 'sys-utils/losetup.8') diff --git a/sys-utils/losetup.8 b/sys-utils/losetup.8 index a6b45a0dd..43dc76815 100644 --- a/sys-utils/losetup.8 +++ b/sys-utils/losetup.8 @@ -68,21 +68,6 @@ to detach loop devices and to query the status of a loop device. If only the \fIloopdev\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 will take the name of an arbitrary encryption type -and find the module that knows how to perform that encryption. .SH OPTIONS The \fIsize\fR and \fIoffset\fR arguments may be followed by binary (2^N) suffixes KiB, MiB, GiB, TiB, PiB and EiB (the "iB" is optional, e.g. "K" has the @@ -122,67 +107,62 @@ print device name if the option and a .I file argument are present. - -The short form of this option (\fB\-s\fP) is deprecated. This short form could -be in collision with Loop-AES implementation where the same option is used for -\fB\-\-sizelimit\fP. .IP "\fB\-v, \-\-verbose\fP" verbose mode +.SH ENCRYPTION +.B Cryptoloop is deprecated in favor of dm-crypt. For more details see +.B cryptsetup (8). It is possible that all bug reports regarding to -E/-e +.B options will be ignored. + + +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 will take the name of an arbitrary encryption type +and find the module that knows how to perform that encryption. + .SH RETURN VALUE .B losetup returns 0 on success, nonzero on failure. When .B losetup displays the status of a loop device, it returns 1 if the device is not configured and 2 if an error occurred which prevented -.B losetup from determining the status of the device. .SH FILES -.nf -/dev/loop0, /dev/loop1, ... loop devices (major=7) -.fi +.TP +.I /dev/loop[0..N] +loop block devices +.TP +.I /dev/loop-cotrol +loop control device + .SH EXAMPLE -If you are using the loadable module you must have the module loaded -first with the command -.IP -# modprobe loop -.LP -Maybe also encryption modules are needed. -.IP -# modprobe des -# modprobe cryptoloop -.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 -Password: -Init (up to 16 hex digits): -# mkfs -t ext2 /dev/loop0 100 -# mount -t ext2 /dev/loop0 /mnt +# dd if=/dev/zero of=~/file.img bs=1MiB count=10 +# losetup --find --show ~/file.img +/dev/loop0 +# mkfs -t ext2 /dev/loop0 +# mount /dev/loop0 /mnt ... # umount /dev/loop0 -# losetup -d /dev/loop0 +# losetup --detach /dev/loop0 .fi -.LP -If you are using the loadable module you may remove the module with -the command -.IP -# rmmod loop -.LP -.fi -.SH RESTRICTION -DES encryption is painfully slow. On the other hand, XOR is terribly weak. - -Cryptoloop is deprecated in favor of dm-crypt. For more details see -.BR cryptsetup (8). +.SH AUTHORS +Karel Zak , based on original version from +Theodore Ts'o .SH AVAILABILITY The losetup command is part of the util-linux package and is available from ftp://ftp.kernel.org/pub/linux/utils/util-linux/. -.\" .SH AUTHORS -.\" .nf -.\" Original version: Theodore Ts'o -.\" Original DES by: Eric Young -.\" .fi -- cgit v1.2.3-55-g7522