Method and apparatus for providing dynamically linked libraries

• US 5,835,749 A
• Filed: 05/05/1995
• Issued: 11/10/1998
• Est. Priority Date: 05/05/1995
• Status: Expired due to Term

• Current Assignee: Apple Inc.
• Original Assignee: Apple Computer Incorporated (Apple Inc.)
• Inventors: Cobb, Jeffrey R.
• Primary Examiner(s): Teska, Kevin J.
• Assistant Examiner(s): Siek, Vuthe
• Application Number:
  US08/435,142
• Time in Patent Office: 1,285 Days
• Field of Search: 395/500, 395/700
• US Class Current: 719/331
• CPC Class Codes: G06F 9/44521 Dynamic linking or loading; Link editing at or after load time, e.g. Java class loading

Abstract

According to the present invention a variety of methods and apparatus for providing dynamically linked libraries are taught. A "standard DLL" is a dynamically linked library (DLL) which is pulled into the data closure of a process by direct reference in the process'"'"' root DLL or by direct reference in other DLLs present in the data closure. In contrast, the present invention teaches a "phantom DLL" which is pushed into the data closure of an executable process and is not directly referenced either by the root DLL or by other DLLs present in the data closure. In some embodiments the phantom DLL includes an anonymous initialization routine which the binding manager executes when the phantom DLL is added to a new process data enclosure. By executing the initialization routine the phantom DLL has an opportunity to execute and impact the computing environment of the new process. A method for dynamically binding a root DLL and a plurality of DLLs into an executable process on a computer system includes the steps of storing a collection of standard DLLs and phantom DLLs in a memory of the computer system, receiving a bind command within an operating system function, determining which standard dynamically linked libraries are needed by the root DLL, and determining which phantom dynamically linked libraries are to be used within the executable process.

Claims

1. A method for dynamically binding a root fragment and a plurality of dynamically linked libraries into an executable process on a computer system comprising the steps of:

storing a DLL collection of standard dynamically linked libraries and phantom dynamically linked libraries in a memory of a computer system;

receiving a bind command within an operating system function executing on said computer system to bind dynamically linked libraries with a root fragment into a new executable process, said operating system function initiating a binding manager executing on said computer system to perform the binding process, said binding manager having access to said DLL collection;

determining within said binding manager which standard dynamically linked libraries are needed by said root fragment, wherein said standard dynamically linked libraries are known to at least one of said root fragment and another of said standard dynamically linked libraries; and

determining which phantom dynamically linked libraries are to be used within said executable process, wherein said phantom dynamically linked libraries are not known to either of said root fragment or said standard dynamically linked libraries needed by said root fragment.

2. A method as recited in claim 1 wherein said step of determining which phantom dynamically linked libraries are to be used within said executable process includes the substeps of:

selecting a phantom dynamically linked library; and

determining that said selected phantom dynamically linked library is to be used within said executable process if said selected phantom dynamically linked library is intended to patch a first dynamically linked library, said first dynamically linked library being selected from a set of libraries including at least said root fragment, said standard dynamically linked libraries needed by said root fragment, and any phantom dynamically linked libraries which have been determined to be used within said executable process.

3. A method as recited in claim 2 wherein said step of determining which phantom dynamically linked libraries are to be used within said executable process further includes the substep of determining that said selected phantom dynamically linked library is not to be used within said executable process if it is determined that said selected phantom dynamically linked library is intended to patch said first dynamically linked library and if said first dynamically linked library is not needed by said root fragment.

4. A method as recited in claim 2 wherein it is determined that said selected phantom dynamically linked library is intended to patch said first dynamically linked library and that said first dynamically linked library is needed by said root fragment, the method further including the step of asking said binding manager to include said selected phantom dynamically linked library within said executable process.

5. A method as recited in claim 2 wherein it is determined that said selected phantom dynamically linked library is not intended to patch a dynamically linked library, the method further including the step of asking said binding manager to include said selected phantom dynamically linked library within said executable process.

6. A method as recited in claim 5 wherein said selected phantom dynamically linked library is operable to self-determine if it is to be used in said executable process.

7. A method as recited in claim 1 wherein said step of determining which phantom dynamically linked libraries are to be used within said executable process includes the substep of each phantom dynamically linked library self-determining if it is to be used in said executable process.

8. A method as recited in claim 1 further including the step of storing a list of dynamically linked libraries each having a corresponding set of at least one phantom dynamically linked library, wherein said step of determining which phantom dynamically linked libraries are to be used within said executable process includes the substeps of:

determining which dynamically linked libraries from said list are needed by said root process; and

for each dynamically linked library from said list which is needed by said root process, determining that said corresponding set of at least one phantom dynamically linked library is to be used within said executable process.

9. A method as recited in claim 8 further including the step of asking said binding manager to include each corresponding set of at least one phantom dynamically linked library which is determined to be used within said executable process.

10. A method as recited in claim 1 wherein said operating system function is a process manager which is operable to provide access to said DLL collection and further manage scheduling and execution of a plurality of processes, said process manager having a process manager root bound to a plurality of dynamically linked libraries, wherein one of said plurality of dynamically linked libraries is said binding manager.

11. A method as recited in claim 1 wherein one of said phantom dynamically linked libraries calls at least one of said root fragment and said standard dynamically linked libraries to register its existence within said executable process.

12. A method as recited in claim 11 wherein said operating system function is an event manager which allows said operating system to monitor computer system inputs and said one of said phantom dynamically linked libraries is a virtual user, said virtual user operable to drive said event manager in such a way that said virtual user mimics operations which a user of said computer system may perform, said operations including pointing with a mouse, typing on a keyboard, and depressing a keypad.

13. A method as recited in claim 1 wherein said step of determining which phantom dynamically linked libraries are to be used within said executable process is performed by said binding manager.

14. A structure for an executable process comprising:

a root fragment including a root functionality of a desired process; and

at least one phantom dynamically linked library bound to said executable process, wherein said at least one phantom dynamically linked library performs a phantom library function that is not known by said root fragment,

wherein the combination of said root fragment and said at least one phantom dynamically linked library comprises an executable process on a computer system.

15. A structure as described in claim 14 further including at least one standard dynamically linked library bound to said root fragment, said at least one standard dynamically linked library including a desired library function that is known and called by said root functionality.

16. A structure as described in claim 15 wherein said root fragment comprises:

a call symbol to an import symbol corresponding to said desired library function; and

a table of contents including said import symbol and a pointer to said desired library function.

17. A structure as described in claim 14 wherein said at least one phantom dynamically linked library is a patch operable to augment a given function already implemented on said computer system.

18. A structure as described in claim 14 wherein said at least one phantom dynamically linked library is a patch operable to replace a given function already implemented on said computer system.

19. A structure as described in claim 14 wherein said at least one phantom dynamically linked library is operable to call said root fragment during execution of said executable process.

20. A structure as described in claim 19 wherein said call is arranged to register said at least one phantom dynamically linked library with said root fragment.

21. A computer system comprising:

a central processing unit;

memory accessible by said central processing unit; and

at least one executable process implemented on said central processing unit and said memory, said at least one executable process having a structure as described in claim 14.

22. A binding system for binding dynamically linked libraries to a root process comprising:

a computer system including a central processing unit and memory coupled to said central processing unit;

a DLL collection stored in said memory, said DLL collection including standard dynamically linked libraries and phantom dynamically linked libraries;

a root fragment stored in said memory;

a binding manager stored in said memory and executing on said central processing unit, said binding manager having access to said DLL collection and said root fragment, said binding manager determining which standard dynamically linked libraries are needed by said root fragment, wherein said standard dynamically linked libraries are known to at least one of said root fragment and another of said standard dynamically linked libraries; and

a service stored in said memory and executing on said central processing unit, said service having access to said DLL collection and said root fragment, said service determining which phantom dynamically linked libraries are to be used with said root fragment, wherein said phantom dynamically linked libraries are not known to either of said root fragment or said standard dynamically linked libraries.

23. A binding system as recited in claim 22 wherein said binding manager and said service are one computer process.

24. A binding system as described in claim 22 wherein said root fragment comprises:

a call to an import symbol corresponding to a desired library function from a standard dynamically linked library; and

a table of contents including;

said import symbol; and

a data field corresponding to said import symbol, said data field intended to hold a pointer to said desired library function.

25. A binding system as described in claim 24 wherein said binding manager is operable to store a pointer to said desired library function in said data field.

26. A binding system as described in claim 22 wherein at least one phantom dynamically linked library which is determined to be used with said root fragment is a patch operable to augment a given function already implemented on said computer system.

27. A method for dynamically binding a root fragment and a plurality of dynamically linked libraries into an executable process on a computer system comprising the steps of:

(a) storing a DLL collection of standard dynamically linked libraries and phantom dynamically linked libraries in a memory of a computer system;

(b) receiving a bind command within a service executing on said computer system to bind dynamically linked libraries with a root fragment into a new executable process, said service initiating the binding process;

(c) determining which standard dynamically linked libraries are needed by said root fragment, wherein said standard dynamically linked libraries are known to at least one of said root fragment and another of said standard dynamically linked libraries, said phantom dynamically linked libraries not known to either of said root fragment or said standard dynamically linked libraries needed by said root fragment;

(d) selecting an unprocessed phantom dynamically linked library;

(e) determining if said selected phantom dynamically linked library is intended to patch a one of said standard dynamically linked libraries needed by at least one of said root fragment and another of said standard dynamically lined libraries needed by said root fragment, and, if so, requesting that said selected phantom dynamically linked library be added into said executable process;

(f) requesting that said selected phantom dynamically linked library be added into said executable process if it is determined in step (e) that said selected phantom dynamically linked library is not intended to patch;

(g) marking said selected phantom dynamically linked library as processed;

(h) marking each phantom dynamically linked library which has not been added into said executable process as unprocessed when said selected phantom dynamically linked library is added to said executable process in step (e); and

(i) repeating steps (d)-(h) until each of the phantom dynamically linked libraries are marked as processed.