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0 pointsPanzerschrek2d ago0 comments

> 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?

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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).

j / k navigate · click thread line to collapse

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).

j / k navigate · click thread line to collapse