1RSTARTD(1) General Commands Manual RSTARTD(1)
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52 rstartd - a sample implementation of a Remote Start rsh helper
53
55 rstartd
56 rstartd.real [-c configfilename]
58
60 Rstartd is an implementation of a Remote Start "helper" as defined in
61 "A Flexible Remote Execution Protocol Based on rsh".
62 This document describes the peculiarities of rstartd and how it is con‐
64 figured.
65
67 -c configfilename
68 This option specifies the "global" configuration file that
69 rstartd is to read. Normally, rstartd is a shell script that
70 invokes rstartd.real with the -c switch, allowing local config‐
71 uration of the location of the configuration file. If
72 rstartd.real is started without the -c option, it reads
73 /usr/lib/X11/rstart/config.
74
76 It is critical to successful interoperation of the Remote Start proto‐
77 col that rstartd be installed in a directory which is in the "default"
78 search path, so that default rsh requests and the ilk will be able to
79 find it.
80
82 Rstartd is by design highly configurable. One would like things like
83 configuration file locations to be fixed, so that users and administra‐
84 tors can find them without searching, but reality is that no two ven‐
85 dors will agree on where things should go, and nobody thinks the origi‐
86 nal location is "right". Thus, rstartd allows one to relocate all of
87 its files and directories.
88 Rstartd has a hierarchy of configuration files which are executed in
90 order when a request is made. They are:
91 global config
92 per-user ("local") config
93 global per-context config
94 per-user ("local") per-context config
95 config from request
96 As you might guess from the presence of "config from request", all of
97 the config files are in the format of an rstart request. Rstartd
98 defines a few additional keywords with the INTERNAL- prefix for speci‐
99 fying its configuration.
100 Rstartd starts by reading and executing the global config file. This
102 file will normally specify the locations of the other configuration
103 files and any systemwide defaults.
104 Rstartd will then read the user's local config file, default name
106 $HOME/.rstart.
107 Rstartd will then start interpreting the request.
109 Presumably one of the first lines in the request will be a CONTEXT
111 line. The context name is converted to lower case.
112 Rstartd will read the global config file for that context, default name
114 /usr/lib/X11/rstart/contexts/<name>, if any.
115 It will then read the user's config file for that context, default name
117 $HOME/.rstart.contexts/<name>, if any.
118 (If neither of these exists, rstartd aborts with a Failure message.)
120 Rstartd will finish interpreting the request, and execute the program
122 specified.
123 This allows the system administrator and the user a large degree of
125 control over the operation of rstartd. The administrator has final
126 say, because the global config file doesn't need to specify a per-user
127 config file. If it does, however, the user can override anything from
128 the global file, and can even completely replace the global context
129 config files.
130 The config files have a somewhat more flexible format than requests do;
132 they are allowed to contain blank lines and lines beginning with "#"
133 are comments and ignored. (#s in the middle of lines are data, not
134 comment markers.)
135 Any commands run are provided a few useful pieces of information in
137 environment variables. The exact names are configurable, but the sup‐
138 plied defaults are:
139 $RSTART_CONTEXT the name of the context
140 $RSTART_GLOBAL_CONTEXTS the global contexts directory
141 $RSTART_LOCAL_CONTEXTS the local contexts directory
142 $RSTART_GLOBAL_COMMANDS the global generic commands directory
143 $RSTART_LOCAL_COMMANDS the local generic commands directory
144 $RSTART_{GLOBAL,LOCAL}_CONTEXTS should contain one special file, @List,
145 which contains a list of the contexts in that directory in the format
146 specified for ListContexts. The supplied version of ListContexts will
147 cat both the global and local copies of @List.
148 Generic commands are searched for in several places: (defaults)
150 per-user per-context directory ($HOME/.rstart.commands/<context>)
151 global per-context directory (/usr/lib/X11/rstart/commands/<context>)
152 per-user all-contexts directory ($HOME/.rstart.commands)
153 global all-contexts directory (/usr/lib/X11/rstart/commands)
154 (Yes, this means you can't have an all-contexts generic command with
155 the same name as a context. It didn't seem like a big deal.)
156 Each of these directories should have a file called @List that gives
158 the names and descriptions of the commands in that directory in the
159 format specified for ListGenericCommands.
160
162 There are several "special" rstart keywords defined for rstartd config‐
163 uration. Unless otherwise specified, there are no defaults; related
164 features are disabled in this case.
165 INTERNAL-REGISTRIES name ...
167 Gives a space-separated list of "MISC" registries that this
168 system understands. (Registries other than this are accepted
169 but generate a Warning.)
170 INTERNAL-LOCAL-DEFAULT relative_filename
172 Gives the name ($HOME relative) of the per-user config file.
173 INTERNAL-GLOBAL-CONTEXTS absolute_directory_name
175 Gives the name of the system-wide contexts directory.
176 INTERNAL-LOCAL-CONTEXTS relative_directory_name
178 Gives the name ($HOME relative) of the per-user contexts direc‐
179 tory.
180 INTERNAL-GLOBAL-COMMANDS absolute_directory_name
182 Gives the name of the system-wide generic commands directory.
183 INTERNAL-LOCAL-COMMANDS relative_directory_name
185 Gives the name ($HOME relative) of the per-user generic com‐
186 mands directory.
187 INTERNAL-VARIABLE-PREFIX prefix
189 Gives the prefix for the configuration environment variables
190 rstartd passes to its kids.
191 INTERNAL-AUTH-PROGRAM authscheme program argv[0] argv[1] ...
193 Specifies the program to run to set up authentication for the
194 specified authentication scheme. "program argv[0] ..." gives
195 the program to run and its arguments, in the same form as the
196 EXEC keyword.
197 INTERNAL-AUTH-INPUT authscheme
199 Specifies the data to be given to the authorization program as
200 its standard input. Each argument is passed as a single line.
201 $n, where n is a number, is replaced by the n'th argument to
202 the "AUTH authscheme arg1 arg2 ..." line.
203 INTERNAL-PRINT arbitrary text
205 Prints its arguments as a Debug message. Mostly for rstartd
206 debugging, but could be used to debug config files.
207
209 When using the C shell, or any other shell which runs a script every
210 time the shell is started, the script may get run several times. In
211 the worst case, the script may get run three times:
212 By rsh, to run rstartd
213 By rstartd, to run the specified command
214 By the command, eg xterm
215 rstartd currently limits lines, both from config files and requests, to
216 BUFSIZ bytes.
217 DETACH is implemented by redirecting file descriptors 0,1, and 2 to
219 /dev/null and forking before executing the program.
220 CMD is implemented by invoking $SHELL (default /bin/sh) with "-c" and
222 the specified command as arguments.
223 POSIX-UMASK is implemented in the obvious way.
225 The authorization programs are run in the same context as the target
227 program - same environment variables, path, etc. Long term this might
228 be a problem.
229 In the X context, GENERIC-CMD Terminal runs xterm. In the OpenWindows
231 context, GENERIC-CMD Terminal runs cmdtool.
232 In the X context, GENERIC-CMD LoadMonitor runs xload. In the OpenWin‐
234 dows context, GENERIC-CMD LoadMonitor runs perfmeter.
235 GENERIC-CMD ListContexts lists the contents of @List in both the sys‐
237 tem-wide and per-user contexts directories. It is available in all
238 contexts.
239 GENERIC-CMD ListGenericCommands lists the contents of @List in the sys‐
241 tem-wide and per-user commands directories, including the per-context
242 subdirectories for the current context. It is available in all con‐
243 texts.
244 CONTEXT None is not implemented.
246 CONTEXT Default is really dull.
248 For installation ease, the "contexts" directory in the distribution
250 contains a file "@Aliases" which lists a context name and aliases for
251 that context. This file is used to make symlinks in the contexts and
252 commands directories.
253 All MISC values are passed unmodified as environment variables.
255 One can mistreat rstartd in any number of ways, resulting in anything
257 from stupid behavior to core dumps. Other than by explicitly running
258 programs I don't think it can write or delete any files, but there's no
259 guarantee of that. The important thing is that (a) it probably won't
260 do anything REALLY stupid and (b) it runs with the user's permissions,
261 so it can't do anything catastrophic.
262 @List files need not be complete; contexts or commands which are dull
264 or which need not or should not be advertised need not be listed. In
265 particular, per-user @List files should not list things which are in
266 the system-wide @List files. In the future, perhaps ListContexts and
267 ListGenericCommands will automatically suppress lines from the system-
268 wide files when there are per-user replacements for those lines.
269 Error handling is OK to weak. In particular, no attempt is made to
271 properly report errors on the exec itself. (Perversely, exec errors
272 could be reliably reported when detaching, but not when passing the
273 stdin/out socket to the app.)
274 If compiled with -DODT1_DISPLAY_HACK, rstartd will work around a bug in
276 SCO ODT version 1. (1.1?) (The bug is that the X clients are all com‐
277 piled with a bad library that doesn't know how to look host names up
278 using DNS. The fix is to look up a host name in $DISPLAY and substi‐
279 tute an IP address.) This is a trivial example of an incompatibility
280 that rstart can hide.
281
283 rstart(1), rsh(1), A Flexible Remote Execution Protocol Based on rsh
284
286 Jordan Brown, Quarterdeck Office Systems
287X Version 11 rstart 1.0.2 RSTARTD(1)