Comment by Panzerschrek
7 hours ago
> By letting the linker run arbitrary code before main
As I know C++ allows running arbitrary code before main too - for constructors of global variables. Does it bring security risks too?
7 hours ago
> By letting the linker run arbitrary code before main
As I know C++ allows running arbitrary code before main too - for constructors of global variables. Does it bring security risks too?
It does not, it's actually arbitrary code running during the dynamic loading process, i.e. before _start.
But what if I have a C++ dynamic library? Does it call constructors for global variables before _start function in the main program starts?
_start takes care of calling the global initializers and register the atexit callback for the finalizers.
(In practice _start calls __libc_start_main, a libc function that handles all of that).