1RSTARTD(1) General Commands Manual RSTARTD(1)
51
55 rstartd - a sample implementation of a Remote Start rsh helper
56
58 rstartd
59 rstartd.real [-c configfilename]
61
63 Rstartd is an implementation of a Remote Start "helper" as defined in
64 "A Flexible Remote Execution Protocol Based on rsh".
65 This document describes the peculiarities of rstartd and how it is con‐
67 figured.
68
70 -c configfilename
71 This option specifies the "global" configuration file that
72 rstartd is to read. Normally, rstartd is a shell script that
73 invokes rstartd.real with the -c switch, allowing local config‐
74 uration of the location of the configuration file. If
75 rstartd.real is started without the -c option, it reads
76 /usr/lib/X11/rstart/config.
77
79 It is critical to successful interoperation of the Remote Start proto‐
80 col that rstartd be installed in a directory which is in the "default"
81 search path, so that default rsh requests and the ilk will be able to
82 find it.
83
85 Rstartd is by design highly configurable. One would like things like
86 configuration file locations to be fixed, so that users and administra‐
87 tors can find them without searching, but reality is that no two ven‐
88 dors will agree on where things should go, and nobody thinks the origi‐
89 nal location is "right". Thus, rstartd allows one to relocate all of
90 its files and directories.
91 Rstartd has a hierarchy of configuration files which are executed in
93 order when a request is made. They are:
94 global config
95 per-user ("local") config
96 global per-context config
97 per-user ("local") per-context config
98 config from request
99 As you might guess from the presence of "config from request", all of
100 the config files are in the format of an rstart request. Rstartd
101 defines a few additional keywords with the INTERNAL- prefix for speci‐
102 fying its configuration.
103 Rstartd starts by reading and executing the global config file. This
105 file will normally specify the locations of the other configuration
106 files and any systemwide defaults.
107 Rstartd will then read the user's local config file, default name
109 $HOME/.rstart.
110 Rstartd will then start interpreting the request.
112 Presumably one of the first lines in the request will be a CONTEXT
114 line. The context name is converted to lower case.
115 Rstartd will read the global config file for that context, default name
117 /usr/lib/X11/rstart/contexts/<name>, if any.
118 It will then read the user's config file for that context, default name
120 $HOME/.rstart.contexts/<name>, if any.
121 (If neither of these exists, rstartd aborts with a Failure message.)
123 Rstartd will finish interpreting the request, and execute the program
125 specified.
126 This allows the system administrator and the user a large degree of
128 control over the operation of rstartd. The administrator has final
129 say, because the global config file doesn't need to specify a per-user
130 config file. If it does, however, the user can override anything from
131 the global file, and can even completely replace the global context
132 config files.
133 The config files have a somewhat more flexible format than requests do;
135 they are allowed to contain blank lines and lines beginning with "#"
136 are comments and ignored. (#s in the middle of lines are data, not
137 comment markers.)
138 Any commands run are provided a few useful pieces of information in
140 environment variables. The exact names are configurable, but the sup‐
141 plied defaults are:
142 $RSTART_CONTEXT the name of the context
143 $RSTART_GLOBAL_CONTEXTS the global contexts directory
144 $RSTART_LOCAL_CONTEXTS the local contexts directory
145 $RSTART_GLOBAL_COMMANDS the global generic commands directory
146 $RSTART_LOCAL_COMMANDS the local generic commands directory
147 $RSTART_{GLOBAL,LOCAL}_CONTEXTS should contain one special file, @List,
148 which contains a list of the contexts in that directory in the format
149 specified for ListContexts. The supplied version of ListContexts will
150 cat both the global and local copies of @List.
151 Generic commands are searched for in several places: (defaults)
153 per-user per-context directory ($HOME/.rstart.commands/<context>)
154 global per-context directory (/usr/lib/X11/rstart/commands/<context>)
155 per-user all-contexts directory ($HOME/.rstart.commands)
156 global all-contexts directory (/usr/lib/X11/rstart/commands)
157 (Yes, this means you can't have an all-contexts generic command with
158 the same name as a context. It didn't seem like a big deal.)
159 Each of these directories should have a file called @List that gives
161 the names and descriptions of the commands in that directory in the
162 format specified for ListGenericCommands.
163
165 There are several "special" rstart keywords defined for rstartd config‐
166 uration. Unless otherwise specified, there are no defaults; related
167 features are disabled in this case.
168 INTERNAL-REGISTRIES name ...
170 Gives a space-separated list of "MISC" registries that this
171 system understands. (Registries other than this are accepted
172 but generate a Warning.)
173 INTERNAL-LOCAL-DEFAULT relative_filename
175 Gives the name ($HOME relative) of the per-user config file.
176 INTERNAL-GLOBAL-CONTEXTS absolute_directory_name
178 Gives the name of the system-wide contexts directory.
179 INTERNAL-LOCAL-CONTEXTS relative_directory_name
181 Gives the name ($HOME relative) of the per-user contexts direc‐
182 tory.
183 INTERNAL-GLOBAL-COMMANDS absolute_directory_name
185 Gives the name of the system-wide generic commands directory.
186 INTERNAL-LOCAL-COMMANDS relative_directory_name
188 Gives the name ($HOME relative) of the per-user generic com‐
189 mands directory.
190 INTERNAL-VARIABLE-PREFIX prefix
192 Gives the prefix for the configuration environment variables
193 rstartd passes to its kids.
194 INTERNAL-AUTH-PROGRAM authscheme program argv[0] argv[1] ...
196 Specifies the program to run to set up authentication for the
197 specified authentication scheme. "program argv[0] ..." gives
198 the program to run and its arguments, in the same form as the
199 EXEC keyword.
200 INTERNAL-AUTH-INPUT authscheme
202 Specifies the data to be given to the authorization program as
203 its standard input. Each argument is passed as a single line.
204 $n, where n is a number, is replaced by the n'th argument to
205 the "AUTH authscheme arg1 arg2 ..." line.
206 INTERNAL-PRINT arbitrary text
208 Prints its arguments as a Debug message. Mostly for rstartd
209 debugging, but could be used to debug config files.
210
212 When using the C shell, or any other shell which runs a script every
213 time the shell is started, the script may get run several times. In
214 the worst case, the script may get run three times:
215 By rsh, to run rstartd
216 By rstartd, to run the specified command
217 By the command, eg xterm
218 rstartd currently limits lines, both from config files and requests, to
219 BUFSIZ bytes.
220 DETACH is implemented by redirecting file descriptors 0,1, and 2 to
222 /dev/null and forking before executing the program.
223 CMD is implemented by invoking $SHELL (default /bin/sh) with "-c" and
225 the specified command as arguments.
226 POSIX-UMASK is implemented in the obvious way.
228 The authorization programs are run in the same context as the target
230 program - same environment variables, path, etc. Long term this might
231 be a problem.
232 In the X context, GENERIC-CMD Terminal runs xterm. In the OpenWindows
234 context, GENERIC-CMD Terminal runs cmdtool.
235 In the X context, GENERIC-CMD LoadMonitor runs xload. In the OpenWin‐
237 dows context, GENERIC-CMD LoadMonitor runs perfmeter.
238 GENERIC-CMD ListContexts lists the contents of @List in both the sys‐
240 tem-wide and per-user contexts directories. It is available in all
241 contexts.
242 GENERIC-CMD ListGenericCommands lists the contents of @List in the sys‐
244 tem-wide and per-user commands directories, including the per-context
245 subdirectories for the current context. It is available in all con‐
246 texts.
247 CONTEXT None is not implemented.
249 CONTEXT Default is really dull.
251 For installation ease, the "contexts" directory in the distribution
253 contains a file "@Aliases" which lists a context name and aliases for
254 that context. This file is used to make symlinks in the contexts and
255 commands directories.
256 All MISC values are passed unmodified as environment variables.
258 One can mistreat rstartd in any number of ways, resulting in anything
260 from stupid behavior to core dumps. Other than by explicitly running
261 programs I don't think it can write or delete any files, but there's no
262 guarantee of that. The important thing is that (a) it probably won't
263 do anything REALLY stupid and (b) it runs with the user's permissions,
264 so it can't do anything catastrophic.
265 @List files need not be complete; contexts or commands which are dull
267 or which need not or should not be advertised need not be listed. In
268 particular, per-user @List files should not list things which are in
269 the system-wide @List files. In the future, perhaps ListContexts and
270 ListGenericCommands will automatically suppress lines from the system-
271 wide files when there are per-user replacements for those lines.
272 Error handling is OK to weak. In particular, no attempt is made to
274 properly report errors on the exec itself. (Perversely, exec errors
275 could be reliably reported when detaching, but not when passing the
276 stdin/out socket to the app.)
277 If compiled with -DODT1_DISPLAY_HACK, rstartd will work around a bug in
279 SCO ODT version 1. (1.1?) (The bug is that the X clients are all com‐
280 piled with a bad library that doesn't know how to look host names up
281 using DNS. The fix is to look up a host name in $DISPLAY and substi‐
282 tute an IP address.) This is a trivial example of an incompatibility
283 that rstart can hide.
284
286 rstart(1), rsh(1), A Flexible Remote Execution Protocol Based on rsh
287
289 Jordan Brown, Quarterdeck Office Systems
290X Version 11 rstart 1.0.2 RSTARTD(1)