Determining which process needs to be restarted after update

[Mateusz Guzik]

On Sat, Jan 12, 2013 at 11:29:14PM +0000, Ben Morrow wrote:
> Quoth Derek Kulinski <takeda at takeda.tk>:
> > 
> > I personally really like OpenSuSE command which is: zypper ps
> > What it does is it lists all processes that have files opened that
> > currently don't exist (i.e. link count is 0). This helps tremendously
> > in determining which processes need to be restarted after an update.
> > 
> > Is there something similar for FreeBSD? I was thinking of using
> > lsof +L1, but on FreeBSD that command is not capable of displaying
> > names of files that were deleted, many entries returned are for
> > example processes that have open sockets. It also does not list names
> > of the deleted/replaced files.
> > 
> > Is there a tool that is capable to do such task, or maybe some
> > additional options to lsof? I'm not too familiar with it myself.
> 
> procstat -fa, look for entries with 'v' in the 'T' column and '-' in the
> 'NAME' column (or get awk to look for you). You may also want to check
> the 'V' column: see the manpage for the codes. This won't tell you what
> the file used to be called before it was deleted: I don't think the
> kernel keeps that information.
> 

This has at least 2 problems:
- it will not show shared libraries (-v is required)
- it will report processes with open unlinked files, which is completely
  normal

But even if we use -v, I don't think we can reliably distinguish
"regular" unlinked file mapping from shared library mapping (for
unlinked files we will get - as a name, just like in -f case). I didn't
dig into this though.

Instead I would go upwards in package dependency tree and for each daemon
check if it is running (should be doable without much hackery). Checking
for all binaries may be more problematic.

-- 
Mateusz Guzik <mjguzik gmail.com>