1RSTARTD(1) General Commands Manual RSTARTD(1)
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38 rstartd - a sample implementation of a Remote Start rsh helper
39
41 rstartd
42 rstartd.real [-c configfilename]
44
46 Rstartd is an implementation of a Remote Start "helper" as defined in
47 "A Flexible Remote Execution Protocol Based on rsh".
48 This document describes the peculiarities of rstartd and how it is con‐
50 figured.
51
53 -c configfilename
54 This option specifies the "global" configuration file that
55 rstartd is to read. Normally, rstartd is a shell script that
56 invokes rstartd.real with the -c switch, allowing local config‐
57 uration of the location of the configuration file. If
58 rstartd.real is started without the -c option, it reads
59 /usr/lib/X11/rstart/config.
60
62 It is critical to successful interoperation of the Remote Start proto‐
63 col that rstartd be installed in a directory which is in the "default"
64 search path, so that default rsh requests and the ilk will be able to
65 find it.
66
68 Rstartd is by design highly configurable. One would like things like
69 configuration file locations to be fixed, so that users and administra‐
70 tors can find them without searching, but reality is that no two ven‐
71 dors will agree on where things should go, and nobody thinks the origi‐
72 nal location is "right". Thus, rstartd allows one to relocate all of
73 its files and directories.
74 Rstartd has a hierarchy of configuration files which are executed in
76 order when a request is made. They are:
77 global config
78 per-user ("local") config
79 global per-context config
80 per-user ("local") per-context config
81 config from request
82 As you might guess from the presence of "config from request", all of
83 the config files are in the format of an rstart request. Rstartd de‐
84 fines a few additional keywords with the INTERNAL- prefix for specify‐
85 ing its configuration.
86 Rstartd starts by reading and executing the global config file. This
88 file will normally specify the locations of the other configuration
89 files and any systemwide defaults.
90 Rstartd will then read the user's local config file, default name
92 $HOME/.rstart.
93 Rstartd will then start interpreting the request.
95 Presumably one of the first lines in the request will be a CONTEXT
97 line. The context name is converted to lower case.
98 Rstartd will read the global config file for that context, default name
100 /usr/lib/X11/rstart/contexts/<name>, if any.
101 It will then read the user's config file for that context, default name
103 $HOME/.rstart.contexts/<name>, if any.
104 (If neither of these exists, rstartd aborts with a Failure message.)
106 Rstartd will finish interpreting the request, and execute the program
108 specified.
109 This allows the system administrator and the user a large degree of
111 control over the operation of rstartd. The administrator has final
112 say, because the global config file doesn't need to specify a per-user
113 config file. If it does, however, the user can override anything from
114 the global file, and can even completely replace the global context
115 config files.
116 The config files have a somewhat more flexible format than requests do;
118 they are allowed to contain blank lines and lines beginning with "#"
119 are comments and ignored. (#s in the middle of lines are data, not
120 comment markers.)
121 Any commands run are provided a few useful pieces of information in en‐
123 vironment variables. The exact names are configurable, but the sup‐
124 plied defaults are:
125 $RSTART_CONTEXT the name of the context
126 $RSTART_GLOBAL_CONTEXTS the global contexts directory
127 $RSTART_LOCAL_CONTEXTS the local contexts directory
128 $RSTART_GLOBAL_COMMANDS the global generic commands directory
129 $RSTART_LOCAL_COMMANDS the local generic commands directory
130 $RSTART_{GLOBAL,LOCAL}_CONTEXTS should contain one special file, @List,
131 which contains a list of the contexts in that directory in the format
132 specified for ListContexts. The supplied version of ListContexts will
133 cat both the global and local copies of @List.
134 Generic commands are searched for in several places: (defaults)
136 per-user per-context directory ($HOME/.rstart.commands/<context>)
137 global per-context directory (/usr/lib/X11/rstart/commands/<context>)
138 per-user all-contexts directory ($HOME/.rstart.commands)
139 global all-contexts directory (/usr/lib/X11/rstart/commands)
140 (Yes, this means you can't have an all-contexts generic command with
141 the same name as a context. It didn't seem like a big deal.)
142 Each of these directories should have a file called @List that gives
144 the names and descriptions of the commands in that directory in the
145 format specified for ListGenericCommands.
146
148 There are several "special" rstart keywords defined for rstartd config‐
149 uration. Unless otherwise specified, there are no defaults; related
150 features are disabled in this case.
151 INTERNAL-REGISTRIES name ...
153 Gives a space-separated list of "MISC" registries that this
154 system understands. (Registries other than this are accepted
155 but generate a Warning.)
156 INTERNAL-LOCAL-DEFAULT relative_filename
158 Gives the name ($HOME relative) of the per-user config file.
159 INTERNAL-GLOBAL-CONTEXTS absolute_directory_name
161 Gives the name of the system-wide contexts directory.
162 INTERNAL-LOCAL-CONTEXTS relative_directory_name
164 Gives the name ($HOME relative) of the per-user contexts direc‐
165 tory.
166 INTERNAL-GLOBAL-COMMANDS absolute_directory_name
168 Gives the name of the system-wide generic commands directory.
169 INTERNAL-LOCAL-COMMANDS relative_directory_name
171 Gives the name ($HOME relative) of the per-user generic com‐
172 mands directory.
173 INTERNAL-VARIABLE-PREFIX prefix
175 Gives the prefix for the configuration environment variables
176 rstartd passes to its kids.
177 INTERNAL-AUTH-PROGRAM authscheme program argv[0] argv[1] ...
179 Specifies the program to run to set up authentication for the
180 specified authentication scheme. "program argv[0] ..." gives
181 the program to run and its arguments, in the same form as the
182 EXEC keyword.
183 INTERNAL-AUTH-INPUT authscheme
185 Specifies the data to be given to the authorization program as
186 its standard input. Each argument is passed as a single line.
187 $n, where n is a number, is replaced by the n'th argument to
188 the "AUTH authscheme arg1 arg2 ..." line.
189 INTERNAL-PRINT arbitrary text
191 Prints its arguments as a Debug message. Mostly for rstartd
192 debugging, but could be used to debug config files.
193
195 When using the C shell, or any other shell which runs a script every
196 time the shell is started, the script may get run several times. In
197 the worst case, the script may get run three times:
198 By rsh, to run rstartd
199 By rstartd, to run the specified command
200 By the command, eg xterm
201 rstartd currently limits lines, both from config files and requests, to
202 BUFSIZ bytes.
203 DETACH is implemented by redirecting file descriptors 0,1, and 2 to
205 /dev/null and forking before executing the program.
206 CMD is implemented by invoking $SHELL (default /bin/sh) with "-c" and
208 the specified command as arguments.
209 POSIX-UMASK is implemented in the obvious way.
211 The authorization programs are run in the same context as the target
213 program - same environment variables, path, etc. Long term this might
214 be a problem.
215 In the X context, GENERIC-CMD Terminal runs xterm. In the OpenWindows
217 context, GENERIC-CMD Terminal runs cmdtool.
218 In the X context, GENERIC-CMD LoadMonitor runs xload. In the OpenWin‐
220 dows context, GENERIC-CMD LoadMonitor runs perfmeter.
221 GENERIC-CMD ListContexts lists the contents of @List in both the sys‐
223 tem-wide and per-user contexts directories. It is available in all
224 contexts.
225 GENERIC-CMD ListGenericCommands lists the contents of @List in the sys‐
227 tem-wide and per-user commands directories, including the per-context
228 subdirectories for the current context. It is available in all con‐
229 texts.
230 CONTEXT None is not implemented.
232 CONTEXT Default is really dull.
234 For installation ease, the "contexts" directory in the distribution
236 contains a file "@Aliases" which lists a context name and aliases for
237 that context. This file is used to make symlinks in the contexts and
238 commands directories.
239 All MISC values are passed unmodified as environment variables.
241 One can mistreat rstartd in any number of ways, resulting in anything
243 from stupid behavior to core dumps. Other than by explicitly running
244 programs I don't think it can write or delete any files, but there's no
245 guarantee of that. The important thing is that (a) it probably won't
246 do anything REALLY stupid and (b) it runs with the user's permissions,
247 so it can't do anything catastrophic.
248 @List files need not be complete; contexts or commands which are dull
250 or which need not or should not be advertised need not be listed. In
251 particular, per-user @List files should not list things which are in
252 the system-wide @List files. In the future, perhaps ListContexts and
253 ListGenericCommands will automatically suppress lines from the system-
254 wide files when there are per-user replacements for those lines.
255 Error handling is OK to weak. In particular, no attempt is made to
257 properly report errors on the exec itself. (Perversely, exec errors
258 could be reliably reported when detaching, but not when passing the
259 stdin/out socket to the app.)
260 If compiled with -DODT1_DISPLAY_HACK, rstartd will work around a bug in
262 SCO ODT version 1. (1.1?) (The bug is that the X clients are all com‐
263 piled with a bad library that doesn't know how to look host names up
264 using DNS. The fix is to look up a host name in $DISPLAY and substi‐
265 tute an IP address.) This is a trivial example of an incompatibility
266 that rstart can hide.
267
269 rstart(1), rsh(1), A Flexible Remote Execution Protocol Based on rsh
270
272 Jordan Brown, Quarterdeck Office Systems
273X Version 11 rstart 1.0.2 RSTARTD(1)