On Mon, Sep 30, 2024 at 12:33:18PM GMT, Florian Weimer wrote: > * Lorenzo Stoakes: > > > If you wish to utilise a pidfd interface to refer to the current process > > (from the point of view of userland - from the kernel point of view - the > > thread group leader), it is rather cumbersome, requiring something like: > > > > int pidfd = pidfd_open(getpid(), 0); > > > > ... > > > > close(pidfd); > > > > Or the equivalent call opening /proc/self. It is more convenient to use a > > sentinel value to indicate to an interface that accepts a pidfd that we > > simply wish to refer to the current process. > > The descriptor will refer to the current thread, not process, right? No it refers to the current process (i.e. thread group leader from kernel perspective). Unless you specify PIDFD_THREAD, this is the same if you did the above. > > The distinction matters for pidfd_getfd if a process contains multiple > threads with different file descriptor tables, and probably for > pidfd_send_signal as well. You mean if you did a strange set of flags to clone()? Otherwise these are shared right? Again, we are explicitly looking at process not thread from userland perspective. A PIDFD_SELF_THREAD might be possible, but this series doesn't try to implement that. > > Thanks, > Florian >
