Library loading in remote process

[rhuizer]

Currently pt_inject can be used to execute code in a pt_process. Although this is a very low-level primitive, it is not very flexible. An additional function for loading shared libraries into processes is therefore desirable.

One approach is to describe shared libraries using pt_module, and add a function such as pt_process_module_load(struct pt_process *p, struct pt_module *m) to load them into processes. The drawback here is that it adds additional meaning to the pt_module structure, which would now describe both shared libraries loaded into a debuggee process, as well as on disk shared libraries. This weakens type safety, and creates behind the scenes management code overhead.

Another approach is to add pt_process_library_load(struct pt_process *p, const char *pathname), which is simple, but does not allow for other shared library representations than one that can be referred to by a pathname. In other words, we could load shared libraries from disk, but not from memory.

Finally, a new structure such as pt_library could be added to refer to libraries external to the debuggee, and the new function would be pt_process_library_load(struct pt_process *p, struct pt_library *l). Once loaded it would then appear as a pt_module within the debuggee process.

The last option has my preference, but I'm leaving this open for a bit for further discussion and contemplation.