Sun Microsystems, Inc.

Roger A Faulkner

Joseph R Eykholt

Timothy Paul Marsland

Daniel B Price

Henry H Knapp, Iii

The present invention relates to managing defunct processes. A parent process that does not collect exit information associated with a child process may leave a defunct child process. A defunct child process is identified. The parent process of the defunct child process is modified. The parent process can be modified by changing an existing thread or instantiating a new thread to collect exit information associated with the child process. Collecting exit information causes the removal of the defunct child process.

Methods and apparatus for managing defunct processes

A computer program or a computer process is provided by replacing a native computer instruction with a trapping computer instruction which is the size of the native computer instruction and which, when executed, causes a trap to the kernel. A trap handler in the kernel determines that the inserted trapping computer instruction caused the trap and transfers control to a user trap handler. The user trap handler maps the trap site to a patch of computer instructions. When the trapping computer instruction is executed, the trap handler transfers control from the kernel to the user trap handler which in turn transfers control to the patch. Native computer instructions in sufficient proximity to corresponding patches of computer instructions may be replaced with branching computer instructions of the size of the native computer instruction and which transfer control to those corresponding patches. Other native computer instructions are replaced with trapping computer instructions which transfer control to corresponding patches through traps to the kernel. Unanticipated traps may be handled by mapping all trap sites other than those corresponding to inserted trapping computer instructions to a default patch which processes unanticipated traps. Native computer instructions may be replaced with a selected privileged computer instruction. The kernel trap handler transfers control to the user trap handler if a trap is caused by the selected privileged computer instruction and a user trap handler is installed. Information regarding affected components of the state of the computer process prior to the trap is retrieved and stored.

Method and apparatus for providing and handling traps

Apparatus, methods and computer program products are disclosed that create an 'agent LWP' in a target process. Creation of the agent LWP allows a controlling process to control execution of computer instructions within the target process without co-opting an existing LWP in the target process. The invention thus provides a mechanism that does not unintentionally change the state of the target process because existing partially-completed system calls do not need to be aborted and reissued.

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Mountain View, CA, United States of America

Roger A Faulkner