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u9fs 5.2 KB

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  1. .TH U9FS 4
  2. .SH NAME
  3. u9fs \- serve 9P from Unix
  4. .SH SYNOPSIS
  5. .B u9fs
  6. [
  7. .B -Dnz
  8. ]
  9. [
  10. .B -a
  11. .I authtype
  12. ]
  13. [
  14. .B -A
  15. .I autharg
  16. ]
  17. [
  18. .B -l
  19. .I logfile
  20. ]
  21. [
  22. .B -m
  23. .I msize
  24. ]
  25. [
  26. .B -u
  27. .I onlyuser
  28. ]
  29. .I fsroot
  30. .SH DESCRIPTION
  31. .I U9fs
  32. is
  33. .I not
  34. a Plan 9 program. Instead it is a program that
  35. serves Unix files to Plan 9 machines using the 9P protocol
  36. (see
  37. .IR intro (5)).
  38. It is typically invoked on a
  39. Unix machine by
  40. .B inetd
  41. with its standard input and output connected to a
  42. network connection, typically TCP on an Ethernet.
  43. It typically runs as user
  44. .B root
  45. and multiplexes access to multiple Plan 9 clients over the single wire.
  46. It assumes Plan 9 uids match Unix login names,
  47. and changes to the corresponding Unix effective uid when processing requests.
  48. Characters in file and directory names unacceptable to Plan 9 are translated
  49. into a three-character sequence:
  50. .L \e
  51. followed by two hexadecimal digits.
  52. .I U9fs
  53. serves both 9P1 (the 9P protocol as used by
  54. the second and third editions of Plan 9) and 9P2000.
  55. .PP
  56. The options are:
  57. .TF "\fL-A \fIautharg"
  58. .PD
  59. .TP
  60. .B -D
  61. Write very chatty debugging output to the log file (see
  62. .B -l
  63. option below).
  64. .TP
  65. .B -n
  66. Signals that
  67. .I u9fs
  68. is
  69. .I not
  70. being invoked with a network connection
  71. on standard input and output, and thus should
  72. not try to determine the remote address of the connection.
  73. This is useful when
  74. .I u9fs
  75. is not invoked from
  76. .I inetd
  77. (see examples below).
  78. .TP
  79. .B -z
  80. Truncate the log file on startup. This is useful mainly when debugging
  81. with
  82. .BR -D .
  83. .TP
  84. .BI -a " authtype
  85. Sets the authentication method to be used.
  86. .I Authtype
  87. should be
  88. .BR rhosts ,
  89. .BR none ,
  90. or
  91. .BR p9any .
  92. The default is
  93. .BR rhosts ,
  94. which uses the
  95. .I ruserok
  96. library call to authenticate users by entries in
  97. .B /etc/hosts.equiv
  98. or
  99. .BR $HOME/.rhosts .
  100. This default is discouraged for all but the most controlled networks.
  101. Specifying
  102. .B none
  103. turns off authentication altogether.
  104. This is useful when
  105. .I u9fs
  106. is not invoked from
  107. .I inetd
  108. (see examples below, or
  109. .I srvssh
  110. in
  111. .IR srv (4)).
  112. Specifying
  113. .B p9any
  114. uses the fourth edition Plan 9 authentication mechanisms.
  115. The file
  116. .BR /etc/u9fs.key ,
  117. or
  118. .I autharg
  119. if specified
  120. (see the
  121. .B -A
  122. option),
  123. is consulted for the authentication data
  124. and should be suitably protected.
  125. This file must contain exactly three lines:
  126. .I secret
  127. (plaintext password),
  128. .I u9fs-user
  129. (user id),
  130. and
  131. .I plan9-auth.dom
  132. (authentication domain).
  133. .RS
  134. .LP
  135. Finally,
  136. .I factotum
  137. must be taught a key of the form:
  138. .LP
  139. .EX
  140. .B
  141. key proto=p9sk1 dom=\fIplan9-auth.dom\fP user=\fIu9fs-user\fP !password=\fIsecret\fP
  142. .EE
  143. .RE
  144. .TP
  145. .BI -A " autharg
  146. Used to specify an argument to the authentication method.
  147. See the authentication descriptions above.
  148. .TP
  149. .BI -l " logfile
  150. Specifies the file which should contain debugging output
  151. and other messages.
  152. The out-of-the-box compile-time default is
  153. .BR /tmp/u9fs.log .
  154. .TP
  155. .BI -m " msize
  156. Set
  157. .I msize
  158. for 9P2000
  159. (see
  160. .IR open (5)).
  161. .TP
  162. .BI -u " user
  163. Treat all attaches as coming from
  164. .IR user .
  165. This is useful in some cases when running without
  166. .IR inetd ;
  167. see the examples.
  168. .PP
  169. If
  170. .I fsroot
  171. is specified,
  172. .I u9fs
  173. will serve only that tree; othwise, it will serve the entire Unix
  174. file system.
  175. .SH EXAMPLES
  176. .PP
  177. Plan 9 calls 9P file service
  178. .B 9fs
  179. with TCP port number 564.
  180. Set up this way on a machine called, say,
  181. .BR kremvax ,
  182. .I u9fs
  183. may be connected to the name space of a Plan 9 process by
  184. .IP
  185. .EX
  186. 9fs kremvax
  187. .EE
  188. .PP
  189. For more information on this procedure, see
  190. .IR srv (4)
  191. and
  192. .IR bind (1).
  193. .PP
  194. By default,
  195. .I u9fs
  196. serves the entire file system of the Unix machine.
  197. It forbids access to devices
  198. because the program is single-threaded and may block unpredictably.
  199. Using the
  200. .B attach
  201. specifier
  202. .B device
  203. connects to a file system identical to the usual system except
  204. it only permits device access (and may block unpredictably):
  205. .IP
  206. .EX
  207. srv tcp!kremvax!9fs
  208. mount -c /srv/tcp!kremvax!9fs /n/kremvax device
  209. .EE
  210. .PP
  211. (The
  212. .B 9fs
  213. command
  214. does not accept an attach specifier.)
  215. Even so,
  216. device access may produce unpredictable
  217. results if the block size of the device is greater than 8192,
  218. the maximum data size of a 9P message.
  219. .PP
  220. The source to
  221. .I u9fs
  222. is in the Plan 9 directory
  223. .BR /sys/src/cmd/unix/u9fs .
  224. To install
  225. .I u9fs
  226. on a Unix system with an ANSI C compiler, copy the source to a directory on that system
  227. and run
  228. .BR make .
  229. Then install the binary in
  230. .BR /usr/etc/u9fs .
  231. Add this line to
  232. .BR inetd.conf :
  233. .IP
  234. .EX
  235. 9fs stream tcp nowait root /usr/etc/u9fs u9fs
  236. .EE
  237. .PP
  238. and this to
  239. .BR services :
  240. .IP
  241. .EX
  242. 9fs 564/tcp 9fs # Plan 9 fs
  243. .EE
  244. .LP
  245. Due to a bug in their
  246. IP software, some systems will not accept the service name
  247. .BR 9fs ,
  248. thinking it
  249. a service number because of the initial digit.
  250. If so, run the service as
  251. .B u9fs
  252. or
  253. .BR 564 .
  254. .PP
  255. On systems where listeners cannot be started,
  256. .IR execnet (4)
  257. is useful for running
  258. .I u9fs
  259. via other network mechanisms; the script
  260. .I srvssh
  261. in
  262. .IR srv (4)
  263. provides this for the
  264. .I ssh
  265. protocol.
  266. .SH SOURCE
  267. .B /sys/src/cmd/unix/u9fs
  268. .SH DIAGNOSTICS
  269. Problems are reported to the
  270. log file specified with the
  271. .B -l
  272. option (default
  273. .BR /tmp/u9fs.log ).
  274. The
  275. .B -D
  276. flag enables chatty debugging.
  277. .SH SEE ALSO
  278. .IR bind (1),
  279. .IR execnet (4),
  280. .IR srv (4),
  281. .IR ip (3),
  282. .IR nfsserver (8)
  283. .SH BUGS
  284. The implementation of devices is unsatisfactory.
  285. .LP
  286. Semantics like remove-on-close or the
  287. atomicity of
  288. .B wstat
  289. are hard to provide exactly.