Patent Publication Number: US-11036619-B2

Title: Bypassing execution of a module in real-time

Description:
BACKGROUND 
     The present invention generally relates to testing load modules, and more specifically, to bypassing execution of a module in real-time. 
     In a development environment, it may be desirable to bypass execution of a module still under development. This may be the case, for example, when a complex application is being developed, but some of the modules for a specific interface or routine are not ready for testing. Rather than waiting for the modules to be completed, it may be preferred to have the ability to test without it. 
     SUMMARY 
     Embodiments of the present invention are directed to a computer-implemented method for bypassing execution of a module in real-time. The method provides locating and loading each target module, in a list of target modules, into system memory. The method further provides establishing a link between each target module and the stubbing framework. The method also provides the stubbing framework beginning execution of an application that includes the plurality of target modules. In response to one of the plurality of target modules being called by the application, control is passed to the stubbing framework. This includes passing to the stubbing framework original registers from the application and a register containing an entry point of the stubbing framework. Execution of each target module in the list of target modules is selectively bypassed, based on a setting of an indicator. Control is returned from the stubbing framework to the target module. 
     Embodiments of the present invention are directed to a system for bypassing execution of a module in real-time. The system includes a memory having computer readable computer instructions, and a processor for executing the computer readable instructions, that when executed, cause the processor to locate and load each target module, in a list of target modules, into system memory. Each target module includes load modules and control sections within the load modules, and a stubbing framework has read-write access to the system memory where the target and the application load modules are loaded. The system provides establishing a link between each target module and the stubbing framework. The system also provides beginning, by the stubbing framework, execution of an application that includes the plurality of target modules. In response to one of the plurality of target modules being called by the application, control is passed to the stubbing framework, including passing to the stubbing framework original registers from the application and a register containing an entry point of the stubbing framework. Each target module in the list of target modules is selectively bypassed or executed based on a setting of an indicator. Control is returned from the stubbing framework to the target module. 
     Embodiments of the invention are directed to a computer program product for determining a caller of a module in real-time, the computer program product comprising a computer readable storage medium having program instructions embodied therewith. The computer readable storage medium is not a transitory signal per se. The program instructions are executable by a processor to cause the processor to perform locating and loading each target module, in a list of target modules, into system memory. The program product further provides establishing a link between each target module and the stubbing framework. The program product also provides the stubbing framework beginning execution of an application that includes the plurality of target modules. In response to one of the plurality of target modules being called by the application, the program product passes control to the stubbing framework, which includes passing to the stubbing framework original registers from the application and a register containing an entry point of the stubbing framework. In response to one of the plurality of target modules being called by the application, control is passed to the stubbing framework, wherein the passing control includes passing to the stubbing framework original registers from the application and a register containing an entry point of the stubbing framework. Each target module in the list of target modules is selectively bypassed or executed each, based on a setting of an indicator. Control is returned from the stubbing framework to the target module. 
     Additional technical features and benefits are realized through the techniques of the present invention. Embodiments and aspects of the invention are described in detail herein and are considered a part of the claimed subject matter. For a better understanding, refer to the detailed description and to the drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The specifics of the exclusive rights described herein are particularly pointed out and distinctly claimed in the claims at the conclusion of the specification. The foregoing and other features and advantages of the embodiments of the invention are apparent from the following detailed description taken in conjunction with the accompanying drawings in which: 
         FIG. 1  depicts a block diagram of a computer system for use in implementing one or more embodiments of the present invention; 
         FIG. 2  depicts a flow diagram of bypassing execution of a load module, according to one or more embodiments of the present invention; and 
         FIG. 3  depicts a block diagram of an embodiment of a computer system or cloud server in which the present invention may be implemented. 
     
    
    
     The diagrams depicted herein are illustrative. There can be many variations to the diagram or the operations described therein without departing from the spirit of the invention. For instance, the actions can be performed in a differing order or actions can be added, deleted or modified. Also, the term “coupled” and variations thereof describes having a communications path between two elements and does not imply a direct connection between the elements with no intervening elements/connections between them. All of these variations are considered a part of the specification. 
     In the accompanying figures and following detailed description of the disclosed embodiments, the various elements illustrated in the figures are provided with two or three digit reference numbers. 
     DETAILED DESCRIPTION 
     Various embodiments of the invention are described herein with reference to the related drawings. Alternative embodiments of the invention can be devised without departing from the scope of this invention. Various connections and positional relationships (e.g., over, below, adjacent, etc.) are set forth between elements in the following description and in the drawings. These connections and/or positional relationships, unless specified otherwise, can be direct or indirect, and the present invention is not intended to be limiting in this respect. Accordingly, a coupling of entities can refer to either a direct or an indirect coupling, and a positional relationship between entities can be a direct or indirect positional relationship. Moreover, the various tasks and process steps described herein can be incorporated into a more comprehensive procedure or process having additional steps or functionality not described in detail herein. 
     The following definitions and abbreviations are to be used for the interpretation of the claims and the specification. As used herein, the terms “comprises,” “comprising,” “includes,” “including,” “has,” “having,” “contains” or “containing,” or any other variation thereof, are intended to cover a non-exclusive inclusion. For example, a composition, a mixture, process, method, article, or apparatus that comprises a list of elements is not necessarily limited to only those elements but can include other elements not expressly listed or inherent to such composition, mixture, process, method, article, or apparatus. 
     Additionally, the term “exemplary” is used herein to mean “serving as an example, instance or illustration.” Any embodiment or design described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other embodiments or designs. The terms “at least one” and “one or more” may be understood to include any integer number greater than or equal to one, i.e. one, two, three, four, etc. The terms “a plurality” may be understood to include any integer number greater than or equal to two, i.e. two, three, four, five, etc. The term “connection” may include both an indirect “connection” and a direct “connection.” 
     The terms “about,” “substantially,” “approximately,” and variations thereof, are intended to include the degree of error associated with measurement of the particular quantity based upon the equipment available at the time of filing the application. For example, “about” can include a range of ±8% or 5%, or 2% of a given value. 
     In current practice, at a given point during a software development project, the modules may be at various stages of readiness for incorporation into the application. In order to continue to make progress, a module that is not ready for integration, such as functional or system testing, may be replaced by a test stub. This is a substitute module that acts as a temporary replacement for the missing called module. However, re-compiling and/or relinking of the modules is typically required as updated source modules become available for integration and testing. 
     Embodiments of the present invention tend to improve system reliability by providing a stubbing framework for determining in real-time whether a module or control section should execute. In an embodiment, the stubbing framework provides a way to isolate and perform specific tests against a target module, without the effects from other modules in the application. This allows the use a specific module in isolation, without the need for any of the supporting modules that may be required to get to that point in the execution, essentially allowing a user to set up the execution of the specific module without requiring any others. In another embodiment, the stubbing framework provides a way to isolate one or more target modules and analyze its performance with specific argument data. This allows a user to once again isolate a specific module so that performance tests can be made against it. Additionally, the stubbing framework allows a developer to investigate code replacement possibilities specific to the isolated target module. In this case, a user can intercept and stub out existing code for the module, and dynamically allow the call to the module to redirected to a replacement module that has been defined as a callback. This allows a user to provide and test new code that is intended to replace an existing, i.e. older, module. 
     As will be shown in  FIG. 2 , the bypassing is made without modifying either the caller module or target module. Additionally, the bypassing is performed without source code, without modifying or relinking either the caller or target modules, and without the use of debugging or tracing tools. In summary, the stubbing framework execution is self-contained. 
     Turning to the figures,  FIG. 1  depicts an example block diagram of a host computer system/server  12  (server) which is in communication with one or more components. As shown, multiple servers  12  may be distributed over a wide geographic area and be in electronic communication with each other, and with the other components shown in  FIG. 1 , via the network  99 . 
     The server  12  is operational in numerous other computing system environments or configurations. For example, the server  12  may be a standalone machine, a virtual partition on physical host, a clustered server environment, or a distributed cloud computing environment that include any of the above systems or devices, and the like. When practiced in a distributed cloud computing environment, tasks may be performed by both local and remote servers  12  that are linked together and communicate through a communications network, such as the network  99 . 
     The server  12  may be described in the context of executable instructions, such as a program, or more specifically, an operating system (OS)  40  that is an aggregate of program modules  42  being executed by the processing unit  16  to control the operation of the server  12 . Program modules  42  perform particular tasks of the OS  40 , such as process management; memory management; and device management. Specialized program modules  42  can cooperate with the OS  40  to perform source code management functions, such as compiling, linking, and preparing the resulting module(s) for execution by the processing unit  16 . Other specialized source code modules  42  can cooperate with the OS  40  to provide a framework to determine whether the resulting modules should be executed or bypassed during testing. 
     The program modules  42  may be implemented as routines, programs, objects, components, logic, or data structures, for example. The program modules  42  performing the particular tasks may be grouped by function, according to the server  12  component that the program modules  42  control. At least a portion of the program modules  42  may be specialized to execute the stubbing framework of  FIG. 2 . 
     In a distributed computing environment, such as a cloud computing environment, each participating server  12  may be under the control of an OS  40  residing on each local and remote server  12 , respectively. In a virtual machine, also referred to as a virtual server, each instance of the virtual machine is an emulation of a physical computer. A physical computer may host multiple virtual machine instances, each sharing the hardware resources of the physical computer, and each emulating a physical computer. Each of the virtual machine instances is under the control of an OS  40 . 
     As shown in  FIG. 1 , the components of the server  12  may include, but are not limited to, one or more processors or processing units  16 , a system memory  28 , and a bus  18  that couples various system components, such as the system memory  28 , to processor  16 . 
     System memory  28  can include computer system readable media in the form of volatile memory, such as random access memory (RAM)  30  and/or cache memory  32 . The server  12  may further include other removable/non-removable, volatile/non-volatile computer system storage media. 
     By way of example only, a storage system  34  can be provided as one or more devices for reading from and writing to a non-removable, non-volatile magnetic media, such as a hard disk drive (HDD) or an optical disk drive such as a CD-ROM, DVD-ROM. Each device of the storage system  34  can be connected to bus  18  by one or more data media interfaces. The program modules  42 , the OS  40 , and one or more application programs, load modules, source code files, and system parameter files may be stored on the storage system  34  and subsequently loaded into memory  28  for execution, as needed. 
     The server  12  may also communicate with one or more external devices  14  such as a keyboard, a pointing device, a display  24 , etc.; one or more devices that enable a user to interact with the server  12 ; and/or any devices (e.g., network card, modem, etc.) that enable the server  12  to communicate with one or more other computing devices. Such communication can occur via I/O interfaces  22 . Still, the server  12  can communicate with one or more networks such as a local area network (LAN), a general wide area network (WAN), and/or a public network (e.g., the Internet) via a network adapter  20 . As depicted, the network adapter  20  communicates with the other components of the server  12  via bus  18 . 
       FIG. 2  depicts a flow diagram of bypassing, in real-time, a module or control section from executing, according to one or more embodiments of the present invention. 
     In  100 , the stubbing framework begins by loading its master control program. The stubbing framework also loads an input file containing the names of the target modules, and any embedded control sections within a target module that should be bypassed. There can be multiple embedded control sections within a target module, and each of these control sections can be intercepted. Hereinafter, a target module can refer to a load module or a control section within the load module, unless otherwise noted. The input file can be in XML, CSV, or any other file format that the OS  40  of the server  12  can process. The stubbing framework includes a user interface through which a user creates and modifies the input file. For example, a graphical user interface (GUI) can be accessed through a display  24  that is connected to the server  12 , either directly or through the network  99 . The user can also provide input to the stubbing framework through a command interface. In addition to containing the names of the target modules, the input file includes an indicator for each target module that should not be executed. In this way, only a modification to the input file is needed to change the testing status of a target module. 
     The interception handler ( 110 ) of the stubbing framework is loaded and its entry point address is preserved in the master control program. The interception handler searches the load libraries allocated to the stubbing framework to locate each target module listed in the input file. The operating system allocates load libraries, files, and other resources as part of dispatching the stubbing framework for execution. The interception handler uses various operating system provided commands and service calls, depending on the operating system architecture and implementation, to search the allocated load libraries for each target module. 
     The master control program, indicated by  115 , dynamically loads each target module listed in the input file. The specific method in which each target module is loaded may vary, depending on the operating system architecture and implementation. However, generally the target module is loaded into memory using an operating system command, such as a LOAD supervisor call, that will allow the modules of the stubbing framework to have write access to the loaded memory. 
     The interception handler inspects the entry point of the loaded target module for injection compatibility. The procedure for locating and inspecting the entry point varies according to the operating system architecture and implementation. However, generally an entry point is identified by a particular sequence of instructions, or by an address in a specific register. 
     Injection compatibility is needed because the injected code in the target module will be used to pass control to the interception handler during the execution of the stubbing framework. Therefore, the interception handler inspects the entry point instructions of the target module to ensure the target module is in a known programming format, and that the interception handler will copy the correct number of bytes that contain the operating system linkage. 
     Once compatibility is determined, the entry point machine instructions from the target module entry point in memory are saved into the interception handler. These bytes provide linkage information to transfer control back to target module after the interception handler finishes execution of that target module. 
     The interception handler injects bytes of machine code into the in-memory copy of the target module at the entry point of the module, or at the entry point of the control section. The entry point of the control section may not be the same as the entry point of the target module, since multiple control sections may be incorporated into a load module. The injected machine code provides linkage between the interception handler and the target module, according to the conventions of the operating system. However, in general, some of the bytes of the injected machine code contain the in-memory address of the interception handler. The rest of the bytes of the injected machine code contain instructions to save the contents of a register in order to preserve it, load the in-memory address of the interception handler into that saved register and then branch to that address using the same register. The in-memory copy of the target module is identified to the operating system, using a supervisor call, for example, an IDENTIFY supervisor call. As a result, when the target module executes, control is transferred to the interception handler. 
     Once the desired interceptions are injected, the master control program starts up the primary user application ( 120 ) containing the injected target modules. The user application and the injected target modules execute as they would had the injection not occurred. When one of the injected modules in the user application is called, interception occurs ( 125 ), and the injected code causes the operating system to pass control to the injected in-memory module. The injected code also causes execution to pass to the interception handler, which receives the application&#39;s original registers, and the saved register containing the entry point of the interception handler. This transfer of control is facilitated by the stubbing framework following the operating system&#39;s linkage convention. 
     The interception handler causes the execution of a target module to be bypassed, when an indicator for that functionality is provided in the input file. When the interception handler intercepts a target module, instead of allowing the target module to execute, the interception handler can return to the application&#39;s continuation address directly. Through changing indicators in the input file, one or more target modules can selectively be bypassed or executed. Therefore, the order of execution of target modules can be altered with only a change to the input file, which does not require re-compiling. 
     In addition to bypassing execution of a target module, the interception handler can invoke a utility module to simulate the target module receiving arguments. The input to the utility module can be provided by a file, through user interaction with the GUI of display  24 , or through a command line. Therefore, the simulated execution of the target module can be modified with only a change to a file that does not require re-compiling. The utility module can return results to the interception handler, as if the results occurred by the target module executing. Then, the interception handler uses the preserved user application registers, along with the previously saved user application code from the injection, to restore the complete set of registers and then call the user application&#39;s continuation address, where it will continue to execute normally. 
     Once the utility module, if any, completes, control returns to the interception handler, the interception handler restores the entry point machine instructions from the target module entry point that were saved into the interception handler. The interception handler returns to the application&#39;s continuation address, where the application continues to execute normally ( 135 ) until the next interception causes the process to repeat. Any argument changes made by the callback module are also returned to the calling application. The interception handler may record a report of the actions taken during its execution, including argument changes; target modules executed, along with their calling modules; the order of execution of the target modules; and those target modules that are bypassed. This allows the module to be bypassed, but have its execution simulated. 
     The continuation address is typically the next sequential instruction in the application following the instruction that caused the branch into the interception handler. However, the continuation instruction can be altered by the application or by the interception handler. In the case where there are multiple control sections to be intercepted and inspected within a target module, control will pass back to the interception handler, where the target module continues to execute until the next control section, and the process of  125 ,  130 , and  135  repeats. 
     Once all target modules are inspected, execution ends ( 140 ), any recorded application relationship information is saved for later analysis, or for display at the GUI on the display  24 . 
       FIG. 3  is a block diagram of internal and external components of computers and servers depicted in  FIG. 1  according to at least one embodiment. 
     It should be appreciated that  FIG. 3  provides only an illustration of one implementation and does not imply any limitations with regard to the environments in which different embodiments may be implemented. Many modifications to the depicted environments may be made based on design and implementation requirements. 
     Data processing system  800 ,  900  is representative of any electronic device capable of executing machine-readable program instructions. Data processing system  800 ,  900  may be representative of a smart phone, a computer system, PDA, or other electronic devices. Examples of computing systems, environments, and/or configurations that may represented by data processing system  800 ,  900  include, but are not limited to, personal computer systems, server computer systems, thin clients, thick clients, hand-held or laptop devices, multiprocessor systems, microprocessor-based systems, network PCs, minicomputer systems, and distributed cloud computing environments that include any of the above systems or devices. 
     The computer system  12  may include respective sets of internal components  800  and external components  900  illustrated in  FIG. 3 . Each of the sets of internal components  800  includes one or more processors  820 , one or more computer-readable RAMs  822  and one or more computer-readable ROMs  824  on one or more buses  826 , and one or more operating systems  828  and one or more computer-readable tangible storage devices  830 . The one or more operating systems  828  and programs may be stored on one or more computer-readable tangible storage devices  830  for execution by one or more processors  820  via one or more RAMs  822  (which typically include cache memory). In the embodiment illustrated in  FIG. 3 , each of the computer-readable tangible storage devices  830  is a magnetic disk storage device of an internal hard drive. Alternatively, each of the computer-readable tangible storage devices  830  is a semiconductor storage device such as ROM  824 , EPROM, flash memory or any other computer-readable tangible storage device that can store a computer program and digital information. 
     Each set of internal components  800  also includes a R/W drive or interface  832  to read from and write to one or more portable computer-readable tangible storage devices  936  such as a CD-ROM, DVD, memory stick, magnetic tape, magnetic disk, optical disk or semiconductor storage device. The stubbing framework can be stored on one or more of the respective portable computer-readable tangible storage devices  936 , read via the respective R/W drive or interface  832  and loaded into the respective hard drive  830 . 
     Each set of internal components  800  may also include network adapters (or switch port cards) or interfaces  836  such as a TCP/IP adapter cards, wireless Wi-Fi interface cards, or wireless interface cards or other wired or wireless communication links. The software components of the stubbing framework can be downloaded from an external computer (e.g., server) via a network (for example, the Internet, a local area network or other, wide area network) and respective network adapters or interfaces  836 . From the network adapters (or switch port adaptors) or interfaces  836 , the software components of the stubbing framework are loaded into the respective hard drive  830 . The network may comprise copper wires, optical fibers, wireless transmission, routers, firewalls, switches, gateway computers and/or edge servers. 
     Each of the sets of external components  900  can include a computer display monitor  920 , a keyboard  930 , and a computer mouse  934 . External components  900  can also include touch screens, virtual keyboards, touch pads, pointing devices, and other human interface devices. Each of the sets of internal components  800  also includes device drivers  840  to interface to computer display monitor  920 , keyboard  930  and computer mouse  934 . The device drivers  840 , R/W drive or interface  832  and network adapter or interface  836  comprise hardware and software (stored in storage device  830  and/or ROM  824 ). 
     The present invention may be a system, a method, and/or a computer program product at any possible technical detail level of integration. The computer program product may include a computer readable storage medium (or media) having computer readable program instructions thereon for causing a processor to carry out aspects of the present invention. 
     The computer readable storage medium can be a tangible device that can retain and store instructions for use by an instruction execution device. The computer readable storage medium may be, for example, but is not limited to, an electronic storage device, a magnetic storage device, an optical storage device, an electromagnetic storage device, a semiconductor storage device, or any suitable combination of the foregoing. A non-exhaustive list of more specific examples of the computer readable storage medium includes the following: 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), a static random access memory (SRAM), a portable compact disc read-only memory (CD-ROM), a digital versatile disk (DVD), a memory stick, a floppy disk, a mechanically encoded device such as punch-cards or raised structures in a groove having instructions recorded thereon, and any suitable combination of the foregoing. A computer readable storage medium, as used herein, is not to be construed as being transitory signals per se, such as radio waves or other freely propagating electromagnetic waves, electromagnetic waves propagating through a waveguide or other transmission media (e.g., light pulses passing through a fiber-optic cable), or electrical signals transmitted through a wire. 
     Computer readable program instructions described herein can be downloaded to respective computing/processing devices from a computer readable storage medium or to an external computer or external storage device via a network, for example, the Internet, a local area network, a wide area network and/or a wireless network. The network may comprise copper transmission cables, optical transmission fibers, wireless transmission, routers, firewalls, switches, gateway computers and/or edge servers. A network adapter card or network interface in each computing/processing device receives computer readable program instructions from the network and forwards the computer readable program instructions for storage in a computer readable storage medium within the respective computing/processing device. 
     Computer readable program instructions for carrying out operations of the present invention may be assembler instructions, instruction-set-architecture (ISA) instructions, machine instructions, machine dependent instructions, microcode, firmware instructions, state-setting data, configuration data for integrated circuitry, or either source code or object code written in any combination of one or more programming languages, including an object oriented programming language such as Smalltalk, C++, or the like, and procedural programming languages, such as the “C” programming language or similar programming languages. The computer readable program instructions 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). In some embodiments, electronic circuitry including, for example, programmable logic circuitry, field-programmable gate arrays (FPGA), or programmable logic arrays (PLA) may execute the computer readable program instruction by utilizing state information of the computer readable program instructions to personalize the electronic circuitry, in order to perform aspects of the present invention. 
     Aspects of the present invention are described herein 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 readable program instructions. 
     These computer readable program instructions may be provided to a processor of a 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 readable program instructions may also be stored in a computer readable storage medium that can direct a computer, a programmable data processing apparatus, and/or other devices to function in a particular manner, such that the computer readable storage medium having instructions stored therein comprises an article of manufacture including instructions which implement aspects of the function/act specified in the flowchart and/or block diagram block or blocks. 
     The computer readable program instructions may also be loaded onto a computer, other programmable data processing apparatus, or other device to cause a series of operational steps to be performed on the computer, other programmable apparatus or other device to produce a computer implemented process, such that the instructions which execute on the computer, other programmable apparatus, or other device implement 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 instructions, which comprises one or more executable instructions for implementing the specified logical function(s). In some alternative implementations, the functions noted in the blocks 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 software or hardware-based systems that perform the specified functions or acts or carry out combinations of computer instructions. 
     The descriptions of the various embodiments of the present invention have been presented for purposes of illustration, but are not intended to be exhaustive or limited to the embodiments 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 described embodiments. The terminology used herein was chosen to best explain the principles of the embodiments, the practical application or technical improvement over technologies found in the marketplace, or to enable others of ordinary skill in the art to understand the embodiments described herein.