Richard B. Johnson writes:
 > On Mon, 30 Apr 2001, Torrey Hoffman wrote:
 > > In general, is there a safe way to replace executable files for
 > > programs that might be running while their on-disk images are
 > > replaced?
 > 
 > Yes. Perfectly safe:
 > 
 > mv /usr/bin/exeimage /usr/bin/exeimage.sav
 > cp /wherever/exeimage /usr/bin/exeimage
 > 
 > 
 > The executing task will continue to use the old image until it exits.

Even more effective is:

mv /wherever/exeimage /usr/bin/exeimage

The kernel keeps around the contents of the old file while
the executing process still runs.

This is also basically how things like libc get installed.
A single mv is not only preserves currently referenced contents,
it is atomic.

Later,
David S. Miller
[EMAIL PROTECTED]
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