tree cd3865a34605be80a272a920713b11df7efcb35b
parent 095fc40ace5ffccd306f39fdd1a40b4faa41b8a0
author Seth Forshee <seth.forshee@canonical.com> 1404336559 -0500
committer Miklos Szeredi <mszeredi@redhat.com> 1492527518 +0200

fuse: Add support for pid namespaces

When the userspace process servicing fuse requests is running in
a pid namespace then pids passed via the fuse fd are not being
translated into that process' namespace. Translation is necessary
for the pid to be useful to that process.

Since no use case currently exists for changing namespaces all
translations can be done relative to the pid namespace in use
when fuse_conn_init() is called. For fuse this translates to
mount time, and for cuse this is when /dev/cuse is opened. IO for
this connection from another namespace will return errors.

Requests from processes whose pid cannot be translated into the
target namespace will have a value of 0 for in.h.pid.

File locking changes based on previous work done by Eric
Biederman.

Signed-off-by: Seth Forshee <seth.forshee@canonical.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>