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rmid(1) Remote Method Invocation (RMI) Tools rmid(1)
NAME
rmid - Starts the activation system daemon that enables objects to be registered and
activated in a Java Virtual Machine (JVM).
SYNOPSIS
rmid [options]
options
The command-line options. See Options.
DESCRIPTION
The rmid command starts the activation system daemon. The activation system daemon must be
started before activatable objects can be either registered with the activation system or
activated in a JVM. For details on how to write programs that use activatable objects, the
Using Activation tutorial at
http://docs.oracle.com/javase/8/docs/technotes/guides/rmi/activation/overview.html
Start the daemon by executing the rmid command and specifying a security policy file, as
follows:
rmid -J-Djava.security.policy=rmid.policy
When you run Oracle's implementation of the rmid command, by default you must specify a
security policy file so that the rmid command can verify whether or not the information in
each ActivationGroupDesc is allowed to be used to start a JVM for an activation group.
Specifically, the command and options specified by the CommandEnvironment and any
properties passed to an ActivationGroupDesc constructor must now be explicitly allowed in
the security policy file for the rmid command. The value of the
sun.rmi.activation.execPolicy property dictates the policy that the rmid command uses to
determine whether or not the information in an ActivationGroupDesc can be used to start a
JVM for an activation group. For more information see the description of the -J-
Dsun.rmi.activation.execPolicy=policy option.
Executing the rmid command starts the Activator and an internal registry on the default
port1098 and binds an ActivationSystem to the name java.rmi.activation.ActivationSystem in
this internal registry.
To specify an alternate port for the registry, you must specify the -port option when you
execute the rmid command. For example, the following command starts the activation system
daemon and a registry on the registry's default port, 1099.
rmid -J-Djava.security.policy=rmid.policy -port 1099
START RMID ON DEMAND
An alternative to starting rmid from the command line is to configure inetd (Oracle
Solaris) or xinetd (Linux) to start rmid on demand.
When RMID starts, it attempts to obtain an inherited channel (inherited from inetd/xinetd)
by calling the System.inheritedChannel method. If the inherited channel is null or not an
instance of java.nio.channels.ServerSocketChannel, then RMID assumes that it was not
started by inetd/xinetd, and it starts as previously described.
If the inherited channel is a ServerSocketChannel instance, then RMID uses the
java.net.ServerSocket obtained from the ServerSocketChannel as the server socket that
accepts requests for the remote objects it exports: The registry in which the
java.rmi.activation.ActivationSystem is bound and the java.rmi.activation.Activator remote
object. In this mode, RMID behaves the same as when it is started from the command line,
except in the following cases:
o Output printed to System.err is redirected to a file. This file is located in the
directory specified by the java.io.tmpdir system property (typically /var/tmp or /tmp)
with the prefix rmid-err and the suffix tmp.
o The -port option is not allowed. If this option is specified, then RMID exits with an
error message.
o The -log option is required. If this option is not specified, then RMID exits with an
error message
See the man pages for inetd (Oracle Solaris) or xinetd (Linux) for details on how to
configure services to be started on demand.
OPTIONS
-Coption
Specifies an option that is passed as a command-line argument to each child process
(activation group) of the rmid command when that process is created. For example,
you could pass a property to each virtual machine spawned by the activation system
daemon:
rmid -C-Dsome.property=value
This ability to pass command-line arguments to child processes can be useful for
debugging. For example, the following command enables server-call logging in all
child JVMs.
rmid -C-Djava.rmi.server.logCalls=true
-Joption
Specifies an option that is passed to the Java interpreter running RMID. For
example, to specify that the rmid command use a policy file named rmid.policy, the
-J option can be used to define the java.security.policy property on the rmid
command line, for example:
rmid -J-Djava.security.policy-rmid.policy
-J-Dsun.rmi.activation.execPolicy=policy
Specifies the policy that RMID employs to check commands and command-line options
used to start the JVM in which an activation group runs. Please note that this
option exists only in Oracle's implementation of the Java RMI activation daemon. If
this property is not specified on the command line, then the result is the same as
though -J-Dsun.rmi.activation.execPolicy=default were specified. The possible
values of policy can be default, policyClassName, or none.
o default
The default or unspecified value execPolicy allows the rmid command to execute
commands with specific command-line options only when the rmid command was
granted permission to execute those commands and options in the security policy
file that the rmid command uses. Only the default activation group implementation
can be used with the default execution policy.
The rmid command starts a JVM for an activation group with the information in the
group's registered activation group descriptor, an ActivationGroupDesc. The group
descriptor specifies an optional ActivationGroupDesc.CommandEnvironment that
includes the command to execute to start the activation group and any command-
line options to be added to the command line. By default, the rmid command uses
the java command found in java.home. The group descriptor also contains
properties overrides that are added to the command line as options defined as:
-D<property>=<value>.The com.sun.rmi.rmid.ExecPermission permission grants the
rmid command permission to execute a command that is specified in the group
descriptor's CommandEnvironment to start an activation group. The
com.sun.rmi.rmid.ExecOptionPermission permission enables the rmid command to use
command-line options, specified as properties overrides in the group descriptor
or as options in the CommandEnvironment when starting the activation group.When
granting the rmid command permission to execute various commands and options, the
permissions ExecPermission and ExecOptionPermission must be granted to all code
sources.
ExecPermission
The ExecPermission class represents permission for the rmid command to execute a
specific command to start an activation group.
Syntax: The name of an ExecPermission is the path name of a command to grant the
rmid command permission to execute. A path name that ends in a slash (/) and an
asterisk (*) indicates that all of the files contained in that directory where
slash is the file-separator character, File.separatorChar. A path name that ends
in a slash (/) and a minus sign (-) indicates all files and subdirectories
contained in that directory (recursively). A path name that consists of the
special token <<ALL FILES>> matches any file.
A path name that consists of an asterisk (*) indicates all the files in the
current directory. A path name that consists of a minus sign (-) indicates all
the files in the current directory and (recursively) all files and subdirectories
contained in the current directory.
ExecOptionPermission
The ExecOptionPermission class represents permission for the rmid command to use
a specific command-line option when starting an activation group. The name of an
ExecOptionPermission is the value of a command-line option.
Syntax: Options support a limited wild card scheme. An asterisk signifies a wild
card match, and it can appear as the option name itself (matches any option), or
an asterisk (*) can appear at the end of the option name only when the asterisk
(*) follows a dot (.) or an equals sign (=).
For example: * or -Dmydir.* or -Da.b.c=* is valid, but *mydir or -Da*b or ab* is
not.
Policy file for rmid
When you grant the rmid command permission to execute various commands and
options, the permissions ExecPermission and ExecOptionPermission must be granted
to all code sources (universally). It is safe to grant these permissions
universally because only the rmid command checks these permissions.
An example policy file that grants various execute permissions to the rmid
command is:
grant {
permission com.sun.rmi.rmid.ExecPermission
"/files/apps/java/jdk1.7.0/solaris/bin/java";
permission com.sun.rmi.rmid.ExecPermission
"/files/apps/rmidcmds/*";
permission com.sun.rmi.rmid.ExecOptionPermission
"-Djava.security.policy=/files/policies/group.policy";
permission com.sun.rmi.rmid.ExecOptionPermission
"-Djava.security.debug=*";
permission com.sun.rmi.rmid.ExecOptionPermission
"-Dsun.rmi.*";
};
The first permission granted allows the rmid tcommand o execute the 1.7.0 release
of the java command, specified by its explicit path name. By default, the version
of the java command found in java.home is used (the same one that the rmid
command uses), and does not need to be specified in the policy file. The second
permission allows the rmid command to execute any command in the directory
/files/apps/rmidcmds.
The third permission granted, an ExecOptionPermission, allows the rmid command to
start an activation group that defines the security policy file to be
/files/policies/group.policy. The next permission allows the java.security.debug
property to be used by an activation group. The last permission allows any
property in the sun.rmi property name hierarchy to be used by activation groups.
To start the rmid command with a policy file, the java.security.policy property
needs to be specified on the rmid command line, for example:
rmid -J-Djava.security.policy=rmid.policy.
o <policyClassName>
If the default behavior is not flexible enough, then an administrator can
provide, when starting the rmid command, the name of a class whose
checkExecCommand method is executed to check commands to be executed by the rmid
command.
The policyClassName specifies a public class with a public, no-argument
constructor and an implementation of the following checkExecCommand method:
public void checkExecCommand(ActivationGroupDesc desc, String[] command)
throws SecurityException;
Before starting an activation group, the rmid command calls the policy's
checkExecCommand method and passes to it the activation group descriptor and an
array that contains the complete command to start the activation group. If the
checkExecCommand throws a SecurityException, then the rmid command does not start
the activation group and an ActivationException is thrown to the caller
attempting to activate the object.
o none
If the sun.rmi.activation.execPolicy property value is none, then the rmid
command does not perform any validation of commands to start activation groups.
-log dir
Specifies the name of the directory the activation system daemon uses to write its
database and associated information. The log directory defaults to creating a log,
in the directory in which the rmid command was executed.
-port port
Specifies the port the registry uses. The activation system daemon binds the
ActivationSystem, with the name java.rmi.activation.ActivationSystem, in this
registry. The ActivationSystem on the local machine can be obtained using the
following Naming.lookup method call:
import java.rmi.*;
import java.rmi.activation.*;
ActivationSystem system; system = (ActivationSystem)
Naming.lookup("//:port/java.rmi.activation.ActivationSystem");
-stop
Stops the current invocation of the rmid command for a port specified by the -port
option. If no port is specified, then this option stops the rmid invocation running
on port 1098.
ENVIRONMENT VARIABLES
CLASSPATH
Used to provide the system a path to user-defined classes. Directories are
separated by colons, for example: .:/usr/local/java/classes.
SEE ALSO
o java(1)
o Setting the Class Path
JDK 8 21 November 2013 rmid(1)
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On Apache
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