com.dalsemi.shell
Class TINIShell

java.lang.Object
  |
  +--com.dalsemi.shell.TINIShell

Direct Known Subclasses:

DefaultTINIShell

public abstract class TINIShell

extends java.lang.Object

This abstract class encapsulates all of the functionality of a system shell for TINI. It interacts between a process and the system OS, and provides the current environment and the user ID of the current process. Methods are provided for converting to and from the numerical user ID and the text representation and for determining whether a particular user is an administrator. A user will be considered an administrator if the most significant bit of their user ID is set.

Field Summary

static byte	adminUID Standard administrator UID.
protected java.util.Hashtable	environment Contains the current environment variables for the process.

Constructor Summary

TINIShell()
Creates the initial environment for a shell.

Method Summary

abstract void	execute(java.lang.Object[] commandLine, SystemInputStream in, SystemPrintStream out, SystemPrintStream err, java.util.Hashtable env) Executes a command in the shell.
abstract java.util.Hashtable	getCurrentEnvironment() Returns a copy of the current environment.
abstract byte	getCurrentUID() Returns the user ID of the current user.
abstract java.lang.String	getCurrentUserName() Returns the name of the current user logged in.
abstract java.lang.String	getFromCurrentEnvironment(java.lang.String key) Gets the value of the given key from the current environment.
abstract java.lang.String	getName() Returns the name of the shell.
java.util.Hashtable	getSystemEnvironment() Returns the system environment (the environment that all processes see when they start up).
abstract int	getUIDByUserName(java.lang.String username) Returns the ID of the user with the given user name.
abstract java.lang.String	getUserNameByUID(byte uid) Returns the user name of the user with the given user ID.
abstract java.lang.String	getVersion() Returns the version of the shell.
boolean	isAdmin(byte uid) Determines if the given user ID has administrative rights.
boolean	isCurrentUserAdmin() Indicates whether or not the current user has admin privileges.
abstract int	login(java.lang.String userName, java.lang.String password) Logs a user into the system and sets that user's privilege level correctly.
abstract void	logout(java.lang.Object info) Logs the current user out of the system, returning the privilege level of the current process to the default state.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

adminUID

public static final byte adminUID

Standard administrator UID. Also used as mask to determine if other UIDs are administrators.

environment

protected java.util.Hashtable environment

Contains the current environment variables for the process.

Constructor Detail

TINIShell

public TINIShell()

Creates the initial environment for a shell. The environment is initialized to hold the current working directory. This value is stored under the "current directory" key.

Method Detail

login

public abstract int login(java.lang.String userName,
                          java.lang.String password)

Logs a user into the system and sets that user's privilege level correctly. Most shells will have a list of valid users and their corresponding passwords and user id's to consult when this method is called. (Such as a passwd file.)

Parameters:

userName - the user name of the user logging in

password - the password for this user

logout

public abstract void logout(java.lang.Object info)

Logs the current user out of the system, returning the privilege level of the current process to the default state.

Parameters:

info - any extra information needed in the logout process

getName

public abstract java.lang.String getName()

Returns the name of the shell.

Returns:

the name of the shell

getVersion

public abstract java.lang.String getVersion()

Returns the version of the shell.

Returns:

the shell version

isCurrentUserAdmin

public boolean isCurrentUserAdmin()

Indicates whether or not the current user has admin privileges.

Returns:

true if the user has admin rights, false otherwise

getCurrentUID

public abstract byte getCurrentUID()

Returns the user ID of the current user.

Returns:

the current user's ID

isAdmin

public boolean isAdmin(byte uid)

Determines if the given user ID has administrative rights.

Parameters:

uid - the user ID

Returns:

true if the user is an administrator, false otherwise

getUserNameByUID

public abstract java.lang.String getUserNameByUID(byte uid)

Returns the user name of the user with the given user ID.

Parameters:

uid - the uid to check

Returns:

the user name of the user with the given user ID, or null if that ID is not valid

getUIDByUserName

public abstract int getUIDByUserName(java.lang.String username)

Returns the ID of the user with the given user name.

Parameters:

username - the username to check

Returns:

the ID of the user with the given user name, or -1 if that user does not exist

getCurrentUserName

public abstract java.lang.String getCurrentUserName()

Returns the name of the current user logged in.

Returns:

the name of the current user

getSystemEnvironment

public java.util.Hashtable getSystemEnvironment()

Returns the system environment (the environment that all processes see when they start up). The Hashtable that is returned is a clone of the original.

Returns:

a copy of the system environment

getCurrentEnvironment

public abstract java.util.Hashtable getCurrentEnvironment()

Returns a copy of the current environment.

Returns:

the environment

getFromCurrentEnvironment

public abstract java.lang.String getFromCurrentEnvironment(java.lang.String key)

Gets the value of the given key from the current environment.

Parameters:

key - the key to lookup in the current environment

Returns:

the value of the key, or null if the key is not set in the current environment

execute

public abstract void execute(java.lang.Object[] commandLine,
                             SystemInputStream in,
                             SystemPrintStream out,
                             SystemPrintStream err,
                             java.util.Hashtable env)
                      throws java.lang.Exception

Executes a command in the shell.

Parameters:

commandLine - an Object array containing the command in the first element, followed by any parameters need for that command in a String[] in the second element

in - the stream the command will use to get input

out - the stream used to report non-critical messages

err - the stream used to report critical messages

env - a table of environment variables

Throws:

java.lang.Exception - any exception raised by the command