inject sharelib into process#
hotpatch#
Introduction to Hotpatch#
Hotpatch is a library that can be used to dynamically load a shared library (.so) file on Linux from one process into another already running process, without affecting the execution of the target process. The API is a C API, but also supported in C++.
The current version is 0.2.
The limitations, directions on how to use, and possible uses of hotpatch will be explained in this document.
The main idea of hotpatch stems from the fact that in Linux, it is not easy to load a library into another already running process. In Windows, there is an API called CreateRemoteThread() that can load a library into another process very easily with a couple of API calls. Hotpatch makes this functionality available to Linux users and developers, with a single API call. Unlike other available injection libraries, hotpatch restores the execution of the process to its original state.
The user can do the following with hotpatch:
load his/her own .so file into an already running process
invoke a custom symbol/function in that .so file
pass arguments to that function as long as it is serialized to the form of a byte buffer and length of the buffer. This shall be explained more later.