System and method for processing breakpoint events in a child process generated by a parent process

• US 20040268315A1
• Filed: 06/27/2003
• Published: 12/30/2004
• Est. Priority Date: 06/27/2003
• Status: Active Grant

• Current Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Original Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Inventors: Saraswati, Sujoy, Hundt, Robert, Gouriou, Eric
• Granted Patent: US 7,185,320 B2
• Time in Patent Office: Days
• US Class Current: 717/129
• CPC Class Codes: G06F 11/362 Software debugging

Abstract

A software tool includes logic configured to enable a child process that inherits the address space of a modified parent process to execute an unaltered version of the address space when the child process inherits the altered address space of the parent process. A method for processing breakpoint events in a child process created from a parent process, when the parent process is modified by a software tool includes, storing unmodified parent process code replaced by each occurrence of a breakpoint inserted into the address space during modification of the parent process, monitoring execution of a child process created by the parent process for an initial breakpoint in the address space, suspending execution of the child process in response to an initial breakpoint, replacing each occurrence of a breakpoint in the address space with the unmodified parent process code, and resuming execution of the child process.

Claims

1. A software tool, comprising:

logic configured to enable a child process that inherits the address space of an instrumented parent process to execute as if the child process was generated from an unaltered version of the address space when the child process inherits the altered address space of the parent process.

2. The software tool of claim 1, further comprising:

logic configured to enable execution of the altered address space after the child process terminates.

3. The software tool of claim 2, wherein the logic configured to enable execution of the altered address space further comprises:

a breakpoint store configured to receive a list of breakpoints inserted into the address space during instrumentation of the parent process; and

a backpatch engine configured to receive the list, the backpatch engine further configured to reinsert the breakpoints in the address space.

4. The software tool of claim 3, wherein the backpatch engine is responsive to an event indicative of termination of the child process.

5. The software tool of claim 1, wherein the logic configured to enable a child process that inherits the address space of a parent process to execute further comprises:

a process image store configured to receive an original instruction bundle from the address space of the parent process when the original instruction bundle is altered with a breakpoint during binary instrumentation of the parent process; and

a backpatch engine configured to receive the original instruction bundle and replace the breakpoint with the original instruction bundle in the address space.

6. The software tool of claim 5, wherein the backpatch engine is responsive to an event indicative of a breakpoint encountered during execution of the child process.

7. A method for processing breakpoint events in a child process created from a parent process, wherein the parent process is instrumented by a software tool, the method comprising:

storing uninstrumented parent process code replaced by each occurrence of a breakpoint inserted into the address space during instrumentation of the parent process;

monitoring execution of a child process created by the parent process for an initial breakpoint in the address space;

suspending execution of the child process in response to the initial breakpoint;

replacing each occurrence of a breakpoint in the address space with the uninstrumented parent process code; and

resuming execution of the child process.

8. The method of claim 7, wherein storing comprises retaining a copy of the instructions replaced by the breakpoint in a process image store.

9. The method of claim 7, wherein monitoring comprises executing a process monitor configured to respond to trace events generated by the child process.

10. A method for run-time measuring a parent process instrumented by a software tool, where the parent process includes a fork instruction, the method comprising:

storing each occurrence of a breakpoint located in an address space associated with a parent process during instrumentation of the parent process;

monitoring execution of the parent process for an indication that the parent process is about to resume execution after the termination of a child process generated in response to a fork instruction, wherein the address space has been altered;

suspending execution of the parent process in response to the indication that the parent process is about to resume after termination of a child process generated in response to the fork instruction;

restoring each breakpoint located in the address space during instrumentation of the parent process to the address space; and

resuming execution of the parent process.

11. The method of claim 10, wherein storing comprises retaining a list including the breakpoint and an associated address in a breakpoint store.

12. The method of claim 11, wherein restoring further comprises applying the list.

13. The method of claim 12, wherein applying comprises inserting the breakpoint at the associated address within the address space.

14. The method of claim 10, wherein monitoring comprises executing a process monitor configured to respond to trace events generated by the parent process.

15. A computer-readable medium, comprising:

logic configured to enable a child process that inherits an instrumented address space of an instrumented parent process to execute as if the child process was generated from an uninstrumented address space; and

logic configured to enable execution of the instrumented parent process after the child process terminates.

16. The computer-readable medium of claim 15, wherein the logic configured to enable execution of the instrumented parent process further comprises:

logic configured to receive a list of breakpoints inserted into the address space during instrumentation of the parent process; and

logic configured to reinsert the breakpoints in the address space.

17. The computer-readable medium of claim 16, wherein the logic configured to reinsert the breakpoints is invoked in response to an indication that the child process has terminated.

18. The computer-readable medium of claim 15, wherein the logic configured enable a child process to execute further comprises:

logic configured to receive an original instruction bundle from the address space of the parent process when the address space is altered by inserting a breakpoint during binary instrumentation of the parent process; and

logic configured to replace the breakpoint with the original instruction bundle in the address space.

19. The computer-readable medium of claim 18, wherein the logic configured to replace the breakpoint with the original instruction bundle is responsive to an indication that child process encountered the breakpoint during execution.