Bug 1100498

Summary: RFE: non-polling mechanism to detect guestmount --no-fork readiness
Product: [Fedora] Fedora Reporter: Colin Walters <walters>
Component: libguestfsAssignee: Richard W.M. Jones <rjones>
Status: CLOSED UPSTREAM QA Contact: Fedora Extras Quality Assurance <extras-qa>
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Version: rawhideCC: mbooth, ptoscano, rjones, virt-maint
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Last Closed: 2014-05-24 18:03:46 UTC Type: Bug
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Description Colin Walters 2014-05-22 22:58:49 UTC 
In bug 916780 a feature was added to guestmount to avoid daemonizing, which allows the caller to watch its status via normal waitpid().  However, at the moment callers still have to use the pid file. 

It's possible to use inotify on the pid file to avoid polling, but another model might be a --with-ready-pipe-fd or so, where the caller provides a pipe (or eventfd) to guestmount, and it writes a byte when it's successfully mounted.
Comment 1 Richard W.M. Jones 2014-05-23 08:44:13 UTC 
It probably works if you set the --pid-file to be a pipe :-)

However we can add a --fd=<N> option, analogous to the
guestunmount option.
Comment 2 Richard W.M. Jones 2014-05-23 10:53:19 UTC 
Patches posted:
https://www.redhat.com/archives/libguestfs/2014-May/msg00091.html
Comment 3 Richard W.M. Jones 2014-05-24 18:03:46 UTC 
This is now available in libguestfs >= 1.27.13.