Patent Publication Number: US-8533734-B2

Title: Application programming interface for managing time sharing option address space

Description:
The present invention relates to mainframe computing, and more specifically, to mainframe computing with time sharing option (TSO). 
     Mainframe computers typically interact with terminals that are communicatively connected to the mainframe. The terminals are operative to send and receive messages and data using TSO messages and interactive system productivity facility (ISPF) messages. TSO allows a user to, for example, create, maintain, and compile programs and interactively test batch and on-line programs. ISPF provides a terminal interface having a set of panels. The panels often include means to run tools on TSO. ISPF often includes an application programming interface (API). 
     BRIEF SUMMARY 
     According to one embodiment of the present invention, a method includes receiving a start request from a client at a launcher application programming interface (API), determining whether an existing time sharing option (TSO) address space associated with a user of the client is available, retrieving security environment data associated with the user from a security product responsive to determining that no existing TSO address space associated with a user of the client is available, saving the retrieved security environment data as a security object, generating a message queue, generating a terminal status block (TSB) and saving the terminal status block, creating a TSO address space in a processor, sending an instruction to the TSO address space to start the TSO address space, and sending a message queue identifier associated with the message queue and an address space token associated with the TSO address space to the client. 
     According to another embodiment of the present invention, a system includes a client processor, and a processor communicatively connected to the client processor, the processor operative to receive a start request from the client processor at a launcher application programming interface (API), determine whether an existing time sharing option (TSO) address space associated with a user of the client is available, retrieve security environment data associated with the user from a security product responsive to determining that no existing TSO address space associated with a user of the client processor is available, save the retrieved security environment data as a security object, generate a message queue, generate a terminal status block (TSB) and save the terminal status block, create a TSO address space in a processor, send an instruction to the TSO address space to start the TSO address space, and send a message queue identifier associated with the message queue and an address space token associated with the TSO address space to the client. 
     According to yet another embodiment of the present invention, a non-transitory computer-readable storage medium including computer executable instructions that, when executed on a processor of a computer apparatus, directs the processor to perform a method where the method comprises receiving a start request from a client at a launcher application programming interface (API), determining whether an existing time sharing option (TSO) address space associated with a user of the client is available, retrieving security environment data associated with the user from a security product responsive to determining that no existing TSO address space associated with a user of the client is available, saving the retrieved security environment data as a security object, generating a message queue, generating a terminal status block (TSB) and saving the terminal status block, creating a TSO address space in a processor, sending an instruction to the TSO address space to start the TSO address space, and sending a message queue identifier associated with the message queue and an address space token associated with the TSO address space to the client. 
     Additional features and advantages are realized through the techniques of the present invention. Other embodiments and aspects of the invention are described in detail herein and are considered a part of the claimed invention. For a better understanding of the invention with the advantages and the features, refer to the description and to the drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
       The subject matter which is regarded as the invention is particularly pointed out and distinctly claimed in the claims at the conclusion of the specification. The forgoing and other features, and advantages of the invention are apparent from the following detailed description taken in conjunction with the accompanying drawings in which: 
         FIG. 1  illustrates a block diagram of an exemplary embodiment of a system. 
         FIG. 2  illustrates a block diagram of an exemplary embodiment of processes that may operate on the processor of  FIG. 1 . 
         FIG. 3  illustrates a block diagram of an exemplary method for initializing and accessing a TSO address space on the processor of  FIG. 1 . 
         FIG. 4  illustrates a block diagram of an exemplary method called by the TSO address space of  FIG. 1  to establish the security environment of the TSO address space and populate the TSO logon command buffer. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  illustrates a block diagram of an exemplary embodiment of a system  100 . The system  100  includes a processor (mainframe)  101  that includes, for example a processor such as a mainframe and associated memory, input, and output devices that are operative to perform, for example, processing tasks and applications, and a user processor  103  that may include, for example a processing terminal or computer that includes a processor, memory, input, output, and display devices that are operative to perform processing tasks and applications and may receive and present data to a user via a graphical user interface (GUI). The user processor  103  includes a web browser and/or web client (client)  102  that operates on a computer and is communicatively connected to the processor  101  via a communicative link  105  that may include, for example, an Internet or other type of network communicative connection. The client  102  is operative to send and receive data to and from the processor  101  and present the data to a user. In the illustrated embodiment, the client  102  acts as a terminal user interface. The processor  101  includes a number of entities that may include for example, applications or services that may be processed and performed by the processor  101 . The processor  101  includes a servlet portion  104  that is communicatively connected to the client  102 . The servlet  104  is operative to send and receive data from the time sharing option (TSO) launcher API  106  and message queues  108 . Each message queue  108  is associated with a time sharing option (TSO) address space and an interactive system productivity facility (ISPF) session. In alternate embodiments, the client  102  and servlet  104  may or may not be present and may depend on a state of the system  100 . Though the illustrated embodiment includes a single client  102 , alternate embodiments may include any number of similar clients  102  that may be communicatively connected to the servlet  104 . The processor  101  may perform or reserve address spaces for any number of message queues  108  and associated TSO  110  and ISPF  112  sessions. 
     In this regard, the servlet  104  provides interfaces for the client  102  to request a TSO  110  address space. Once the TSO address space  110  is reserved, the servlet  104  may send and receive both TSO and ISPF messages to and from the TSO  110  and ISPF  112 . The servlet  104  communicates with the client  102  using a JavaScript Object Notation (JSON) message format and converts messages received from the client  102  into a Unicode Transformation Format-8-bit (UTF-8) format readable by the TSO  110  address space (unless the messages have been received in UTF-8 format) such as, for example, {“TSO RESPONSE”: {“VERSION”:“0100”,“DATA”:“TIME”}} The client  102  is operative to receive JSON messages from the servlet  104  and convert the JSON messages into a format that may be displayed to a user in a web browser interface using a communications protocol such as, for example hypertext transfer markup language (HTML) or another type of communications protocol. The servlet  104  provides a service to the client  102  to, for example, terminate the address space by calling the launcher API  106  and provides “housekeeping duties” to properly maintain the address spaces in the processor  101  by calling the launcher API  106 . In the illustrated embodiments the interactions with the message queues  108 , the launcher API  106  and TSO  110  address spaces may be performed using user credentials provided by the client  102 . The servlet  104  maintains a hash map that maps the client  102  or user to the proper message queue  108  and maintains other pertinent data. 
       FIG. 2  illustrates a block diagram of an exemplary embodiment of processes that may operate on the processor  101  (of  FIG. 1 ).  FIG. 2  includes the TSO  110  address space having the ISPF  112  session with ISPF screens  202 , a command interface portion  204 , and a logon process  206 . The command interface portion  204  is the primary means of interacting with TSO  110 . Commands or data are received as input and messages or prompts are returned as output by TSO  110 . The message queue  108  is operative to send and receive messages between the program  205 , the command interface  204 , and the ISPF screens  202 . The command interface portion  204  may interact through a terminal device, but may also operate by reading from and writing to a file or in the illustrated embodiments, the message queue  108 . An address space  111  that has an established security environment is shown for illustrative purposes. In this regard, the security product  212  is invoked to confirm the identity of the user and the credentials of the user, and authorities are established for the given address space. The address space  111  may include the launcher API  106  and a program  205  that may include, for example a software process that runs in the address space  111 . A terminal status block (TSB)  208  is operative to save data stored and retrieved by the launcher API  106  and the logon process  206 . A session table  210  includes a table stored in common memory that is populated with entries such as, for example, an address space token associated with the TSO  110  address space, a message queue identifier that is associated with a particular message queue  108 , a security environment (ENVR) object associated with the user that may be retrieved from the security product  212  and logon options. The logon options may include, for example, a logon procedure name, a region size, and/or an account number. The ENVR object may include information such as the userid, authorization level, and/or connections to group security profiles. 
       FIG. 3  illustrates a block diagram of an exemplary method for initializing and accessing an address space on the processor  101  (of  FIG. 1 ). Referring to  FIG. 3 , in block  302 , the launcher API  106  receives a request to start a process in a TSO  110  address space from a user via the client  102 . In block  304 , the launcher API  106  determines whether there is an existing TSO  110  address space associated with the user that was previously created by the launcher API  106  and is not being used for another process by checking the session table  210  entries to identify any unused TSO  110  address space that may be available for the user. If a usable address space is available for the user, an identifier of the message queue  108  associated with the identified address space is retrieved along with a token associated with the TSO  110  address space and returned to the caller or client  102 . If no (in block  304 ), the launcher API  106  creates an entry in the session table  210  that is associated with the request in block  307 . A security environment (ENVR) object for the user is retrieved from the security product  212  and saved in block  308 . The security product  212  generates the ENVR object by using an access control environment element (ACEE) associated with the address space  111  (of  FIG. 1 ). In block  310 , a message queue is generated. A terminal status block is generated and saved in a common storage area in block  312 . A common storage area is a portion of memory in the processor  101  that may be accessed by different services operating in different address spaces on the processor  101 . In block  314 , the launcher API  106  determines whether the security environment (ENVR) object, message queue, and TSB have been successfully saved and/or generated. The launcher API  106  may make this determination by, for example, determining whether each of the blocks  307 ,  308 ,  310  and  312  processes have been performed with no errors. If no, an error notification is returned to the caller or client  102  in block  316 . If yes (in block  314 ), a TSO  110  address space is created in block  318 . The TSO  110  address space is created by, for example, reserving an address space by invoking the operating system service to LOGON a new address space. In block  320 , the session table  210  is updated by populating an entry in the session table  210  with the unique address space token associated with the newly created TSO  110  address space, a message queue identifier that is associated with the message queue  108  (which, in turn, is associated with the TSO  110  address space), the security object (ENVR object) associated with the user, and logon options associated with the user. In block  322 , instructions are sent to the operating system to start or initialize the created TSO  110  address space in block  322 . Once the TSO  110  address space is started, the message queue ID and address space token are returned to the client  102  in block  306 . The client  102  may then interact with the TSO  110  address space to run desired programs or services within the TSO  110  address space. Once the TSO  110  address space is started by the operating system, the TSO  110  address space is initialized by a process performed in the TSO  110  address space. 
       FIG. 4  illustrates a block diagram of an exemplary method called by the TSO  110  address space to establish the security environment of the TSO  110  address space and populate the TSO logon command buffer. The TSO logon command is used to complete initialization of the TSO  110  address space and initializes the command interface  204  (of  FIG. 2 ). In this regard, a security environment is established and created in the TSO  110  address space. This occurs when TSO  110  address space initialization process determines that the TSO  110  address space was created by the launcher API  106  as indicated by status information in the TSB  208  (of  FIG. 2 ). The TSO  110  address space initialization process invokes the launcher API  106  service to perform special initialization processing. Referring now to  FIG. 4 , in block  402 , the launcher API  106  determines whether the session table includes an entry with the desired address space token, security object (ENVR object), message queue identifier, and logon options. If the session table entry is not present in the session table  210 , the launcher API  106  may send an error notification to the client  102  in block  404 . If the desired entry is present, the launcher API  106  retrieves the ENVR object, message queue identifier, and logon options in block  406 . In block  408 , the launcher API  106  sends the ENVR object to the security product  212 . The security product  212  creates or recreates the access control environment element (ACEE) that is associated with the ENVR object. In block  410 , the launcher API  106  populates a TSO LOGON command buffer with the retrieved logon options. The launcher API  106  sends the contents of the LOGON command buffer and the message queue identifier to the TSO  110  address space initialization processing in block  412 . Once the security environment is established, TSO control blocks are initialized to associate the message queue  108  with the TSO address space, and instruct the TSO  110  address space to communicate with the client  102  via the message queue  108 . 
     As will be appreciated by one skilled in the art, aspects of the present invention may be embodied as a system, method or computer program product. Accordingly, aspects of the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment (including firmware, resident software, micro-code, etc.) or an embodiment combining software and hardware aspects that may all generally be referred to herein as a “circuit,” “module” or “system.” Furthermore, aspects of the present invention may take the form of a computer program product embodied in one or more computer readable medium(s) having computer readable program code embodied thereon. Any combination of one or more computer readable medium(s) may be utilized. The computer readable medium may be a computer readable signal medium or a computer readable storage medium. A computer readable storage medium may be, for example, but not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. More specific examples (a non-exhaustive list) of the computer readable storage medium would include the following: an electrical connection having one or more wires, a portable computer diskette, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or Flash memory), an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing. In the context of this document, a computer readable storage medium may be any tangible medium that can contain, or store a program for use by or in connection with an instruction execution system, apparatus, or device. 
     A computer readable signal medium may include a propagated data signal with computer readable program code embodied therein, for example, in baseband or as part of a carrier wave. Such a propagated signal may take any of a variety of forms, including, but not limited to, electro-magnetic, optical, or any suitable combination thereof. A computer readable signal medium may be any computer readable medium that is not a computer readable storage medium and that can communicate, propagate, or transport a program for use by or in connection with an instruction execution system, apparatus, or device. 
     Program code embodied on a computer readable medium may be transmitted using any appropriate medium, including but not limited to wireless, wireline, optical fiber cable, RF, etc., or any suitable combination of the foregoing. 
     Computer program code for carrying out operations for aspects of the present invention may be written in any combination of one or more programming languages, including an object oriented programming language such as Java, Smalltalk, C++ or the like and conventional procedural programming languages, such as the “C” programming language, PL/I, or assembler programming languages such as HL/ASM. The program code may execute entirely on the user&#39;s computer, partly on the user&#39;s computer, as a stand-alone software package, partly on the user&#39;s computer and partly on a remote computer or entirely on the remote computer or server. In the latter scenario, the remote computer may be connected to the user&#39;s computer through any type of network, including a local area network (LAN) or a wide area network (WAN), or the connection may be made to an external computer (for example, through the Internet using an Internet Service Provider). 
     Aspects of the present invention are described below with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems) and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and/or block diagrams, and combinations of blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions/acts specified in the flowchart and/or block diagram block or blocks. These computer program instructions may also be stored in a computer readable medium that can direct a computer, other programmable data processing apparatus, or other devices to function in a particular manner, such that the instructions stored in the computer readable medium produce an article of manufacture including instructions which implement the function/act specified in the flowchart and/or block diagram block or blocks. The computer program instructions may also be loaded onto a computer, other programmable data processing apparatus, or other devices to cause a series of operational steps to be performed on the computer, other programmable apparatus or other devices to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide processes for implementing the functions/acts specified in the flowchart and/or block diagram block or blocks. The flowchart and block diagrams in the Figures illustrate the architecture, functionality, and operation of possible implementations of systems, methods and computer program products according to various embodiments of the present invention. In this regard, each block in the flowchart or block diagrams may represent a module, segment, or portion of code, which comprises one or more executable instructions for implementing the specified logical function(s). It should also be noted that, in some alternative implementations, the functions noted in the block may occur out of the order noted in the figures. For example, two blocks shown in succession may, in fact, be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending upon the functionality involved. It will also be noted that each block of the block diagrams and/or flowchart illustration, and combinations of blocks in the block diagrams and/or flowchart illustration, can be implemented by special purpose hardware-based systems that perform the specified functions or acts, or combinations of special purpose hardware and computer instructions. 
     The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one more other features, integers, steps, operations, element components, and/or groups thereof. 
     The corresponding structures, materials, acts, and equivalents of all means or step plus function elements in the claims below are intended to include any structure, material, or act for performing the function in combination with other claimed elements as specifically claimed. The description of the present invention has been presented for purposes of illustration and description, but is not intended to be exhaustive or limited to the invention in the form disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the invention. The embodiment was chosen and described in order to best explain the principles of the invention and the practical application, and to enable others of ordinary skill in the art to understand the invention for various embodiments with various modifications as are suited to the particular use contemplated. 
     The flow diagrams depicted herein are just one example. There may be many variations to this diagram or the steps (or operations) described therein without departing from the spirit of the invention. For instance, the steps may be performed in a differing order or steps may be added, deleted or modified. All of these variations are considered a part of the claimed invention. 
     While the preferred embodiment to the invention had been described, it will be understood that those skilled in the art, both now and in the future, may make various improvements and enhancements which fall within the scope of the claims which follow. These claims should be construed to maintain the proper protection for the invention first described.