Techniques for clearing the internal state of a library

A source computer, comprising:

• a memory;
• and
• one or more processors configured
• to receive a request to migrate an application that is executing in the memory of the source computer, wherein the application comprises a first instance of a dynamic library having one or more functions,
• to generate a log comprising resources allocated to and deallocated from the first instance of the dynamic library in response to executing the application, wherein generating the log comprises recording, by a set of wrapped system library functions, calls from the first instance of the dynamic library to system library functions that allocate and deallocate resources,
• to suspend execution of the application while the first instance of the dynamic library has a current state, to unload the first instance of the dynamic library from the memory,
• to identify, subsequent to unloading the first instance of the dynamic library, any of the resources that were allocated to the first instance of the dynamic library and that are still pending,
• to deallocate the identified resources so as to define a cleaned version of the application that does not comprise any of the allocated resources, and
• to migrate the cleaned version of the application to a destination computer, so that upon the destination computer resuming execution of the application and linking the application on the destination computer to a second instance of the dynamic library, the destination computer replays the log so as to bring the linked second instance of the dynamic library to the current state.

A computer software product for controlling operation of a computer, comprising a non-transitory computer-readable medium, in which program instructions are stored, which instructions, when read by a computer, cause the computer:

• to receive, by a first machine, a request to migrate an application that is executing in a memory of the first machine, wherein the application comprises a first instance of a dynamic library having one or more functions;
• to generate a log comprising resources allocated to and deallocated from the first instance of the dynamic library in response to executing the application, wherein generating the log comprises recording, by a set of wrapped system library functions, calls from the first instance of the dynamic library to system library functions that allocate and deallocate resources;
• to suspend execution of the application while the first instance of the dynamic library has a current state;
• to unload the first instance of the dynamic library from the memory;
• to identify, subsequent to unloading the first instance of the dynamic library, any of the resources that were allocated to the first instance of the dynamic library and that are still pending;
• to deallocate the identified resources so as to define a cleaned version of the application that does not comprise any of the allocated resources;
• and
• to migrate the cleaned version of the application to a destination machine, so that upon the destination machine resuming execution of the application and linking the application on the destination machine to a second instance of the dynamic library, the destination machine replays the log so as to bring the linked second instance of the dynamic library to the current state.