system call interposition using LD_PRELOAD

Jonathan Nieder
Fri Mar 30 02:43:00 GMT 2012

Hi Godmar,

Godmar Back wrote:

> He tells me that for several years now, this is no longer possible with GNU
> libc because functions such as fopen() do not dynamically link against the
> stubs, but rather a local PLT is used. He also claims some system call
> sequences are even inlined in parts of the libc code.
> He is now considering changing libc, but finds that its design does not lend
> itself easily to doing that.
> If this is true, what is the new state of the practice with respect to
> system call interposition?

Use ptrace(2).

Hope that helps,

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