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1 perry 1 LOSETUP
2 !!!LOSETUP
3 NAME
4 SYNOPSIS
5 DESCRIPTION
6 OPTIONS
7 RETURN VALUE
8 FILES
9 EXAMPLE
10 RESTRICTIONS
11 BUGS
12 AUTHORS
13 ----
14 !!NAME
15
16
17 losetup - set up and control loop devices
18 !!SYNOPSIS
19
20
2 PerryLorier 21 __losetup__ [[ __-e__ ''encryption'' ] [[ __-o__ ''offset'' ] [[ __-p__ ''num'' ] ''loop_device file''__
1 perry 22 losetup__ [[ __-d__ ] ''loop_device''
23 !!DESCRIPTION
24
25
26 __losetup__ is used to associate loop devices with
27 regular files or block devices, to detach loop devices and
28 to query the status of a loop device. If only the
29 ''loop_device'' argument is given, the status of the
30 corresponding loop device is shown.
31 !!OPTIONS
32
33
34 __--delete, --detach, -d__
35
36
37 detach the file or device associated with the specified loop
38 device.
39
40
41 __--encryption, -e__ ''encryption''
42
43
44 enable data encryption. The following keywords are
45 recognized:
46
47
48 __NONE__
49
50
51 use no encryption (default).
52
53
54 __XOR__
55
56
57 use a simple XOR encryption.
58
59
60 __AES__
61
62
63 use Advanced Encryption Standard encryption. AES encryption
64 is only available if you are using the international kernel
65 and AES encryption has been enabled in the Crypto API.
66 enabled in the Crypto API.
67
68
69 __Blowfish__
70
71
72 use Blowfish encryption. Blowfish encryption is only
73 available if you are using the international kernel and
74 Blowfish encryption has been enabled in the Crypto
75 API.
76
77
78 __Twofish__
79
80
81 use Twofish encryption. Twofish encryption is only available
82 if you are using the international kernel and Twofish
83 encryption has been enabled in the Crypto API.
84
85
86 __CAST__
87
88
89 use CAST encryption. CAST encryption is only available if
90 you are using the international kernel and CAST encryption
91 has been enabled in the Crypto API.
92
93
94 __DES__
95
96
97 use DES encryption. DES encryption is only available if the
98 optional DES package has been added to the kernel. DES
99 encryption uses an additional start value that is used to
100 protect passwords against dictionary attacks. Use of DES is
101 deprecated.
102
103
104 __DFC__
105
106
107 use DFC encryption. DFC encryption is only available if you
108 are using the international kernel and DFC encryption has
109 been enabled in the Crypto API.
110
111
112 __IDEA__
113
114
115 use IDEA encryption. IDEA encryption is only available if
116 you are using the international kernel and IDEA encryption
117 has been enabled in the Crypto API.
118
119
120 __MARS__
121
122
123 use MARS encryption. MARS encryption is only available if
124 you are using the international kernel and MARS encryption
125 has been enabled in the Crypto API.
126
127
128 __RC5__
129
130
131 use RC5 encryption. RC5 encryption is only available if you
132 are using the international kernel and RC5 encryption has
133 been enabled in the Crypto API.
134
135
136 __RC6__
137
138
139 use RC6 encryption. RC6 encryption is only available if you
140 are using the international kernel and RC6 encryption has
141 been enabled in the Crypto API.
142
143
144 __Serpent__
145
146
147 use Serpent encryption. Serpent encryption is only available
148 if you are using the international kernel and Serpent
149 encryption has been enabled in the Crypto API.
150
151
152 __--offset, -o__ ''offset''
153
154
155 the data start is moved ''offset'' bytes into the
156 specified file or device.
157
158
159 __--pass-fd, -p__ ''num''
160
161
162 read the passphrase from file descriptor ''num'' instead
163 of the terminal.
164
165
166 __--keybits, -k__ ''num''
167
168
169 set the number of bits to use in key to
170 ''num''.
171 !!RETURN VALUE
172
173
174 __losetup__ returns 0 on success, nonzero on failure.
175 When __losetup__ displays the status of a loop device, it
176 returns 1 if the device is not configured and 2 if an error
177 occurred which prevented __losetup__ from determining the
178 status of the device.
179 !!FILES
180
181
182 /dev/loop0,/dev/loop1,... loop devices (major=7)
183 /proc/cipher/* available ciphers
184 !!EXAMPLE
185
186
187 If you are using the loadable module you must have the
188 module loaded first with the command
189
190
191 # insmod loop.o
192
193
194 The following commands can be used as an example of using
195 the loop device.
196
197
198 dd if=/dev/zero of=/file bs=1k count=100
199 losetup -e blowfish /dev/loop0 /file
200 Password :
201 mkfs -t ext2 /dev/loop0 100
202 mount -t ext2 /dev/loop0 /mnt
203 ...
204 umount /dev/loop0
205 losetup -d /dev/loop0
206 If you are using the loadable module you may remove the module with the command
207
208
209 # rmmod loop
210 !!RESTRICTIONS
211
212
213 DES encryption is painfully slow. On the other hand, XOR is
214 terribly weak. Both are insecure nowadays. Some ciphers
215 require a licence for you to be allowed to use
216 them.
217 !!BUGS
218
219
220 CAST, DES, RC5 and Twofish are currently broken and cannot
221 be used.
222 !!AUTHORS
223
224
225 Original version: Theodore Ts'o
226 ----
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