musl libc dynamic loading: execution flow from elf application entry function _start to main

Preface

• Application elf, such as a statically linked application, the entry function is not the main function, but _startthe function

• From _startfunction to main function, after a series of initialization operations of libc

• _start -> _start_c -> ... -> main

• The dynamically compiled and linked application elf has gone through the loading and running process of _dlstart-> _dlstart_c-> ...-> _start-> _start_c-> ...->main

• The purpose of this article: debug and sort out the process of application execution from the entry function to the user program main function

musl ldso entry function execution process

• musl libc.so _dlstart: The entry function of the application. Note that the operation of executing the entry function of musl ldso (that is, musl libc.so) is implemented by the kernel.

• Application entry function execution flow: Whether it is static link or dynamic link, it starts from