exec()

Björn Döbel doebel at os.inf.tu-dresden.de
Thu Oct 23 08:36:23 CEST 2014


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Hi,

On 22.10.2014 17:09, teclis High Elf wrote:
> Could some one please point me to or give me example code to do the
> L4Re equivalent of UNIX exec(), spawn a new process?

as Adam already told you in his mail from Oct 21st, starting a new
program differs on L4 from how it is done in UNIX. The basic steps are:

* Create a new task object to represent the address space.
* Inspect the ELF binary you want to run and load the respective
  segments into this new address space.
* Set up initial capabilities for the new task. These are necessary,
  so that the task has a memory manager, memory allocater, namespace
  etc. set.
* Create a thread within the new task and let it run from the ELF
  binary's start address.

There is a libloader that wraps most of this, especially the setup and
binary loading part. Example users of libloader are pkg/moe, pkg/ned,
and pkg/plr.

Bjoern
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