svn commit: r269656 - in head: bin/ps sys/kern sys/sys
truckman at FreeBSD.org
Thu Aug 7 16:48:29 UTC 2014
On 7 Aug, Konstantin Belousov wrote:
> Author: kib
> Date: Thu Aug 7 05:47:53 2014
> New Revision: 269656
> URL: http://svnweb.freebsd.org/changeset/base/269656
> Correct the problems with the ptrace(2) making the debuggee an orphan.
> One problem is inferior(9) looping due to the process tree becoming a
> graph instead of tree if the parent is traced by child. Another issue
> is due to the use of p_oppid to restore the original parent/child
> relationship, because real parent could already exited and its pid
> reused (noted by mjg).
> Add the function proc_realparent(9), which calculates the parent for
> given process. It uses the flag P_TREE_FIRST_ORPHAN to detect the head
> element of the p_orphan list and than stepping back to its container
> to find the parent process. If the parent has already exited, the
> init(8) is returned.
> Move the P_ORPHAN and the new helper flag from the p_flag* to new
> p_treeflag field of struct proc, which is protected by proctree lock
> instead of proc lock, since the orphans relationship is managed under
> the proctree_lock already.
> The remaining uses of p_oppid in ptrace(PT_DETACH) and process
> reapping are replaced by proc_realparent(9).
Changing the parent process has always seemed like a hack to me. It
seems like the debugger should register itself as an additional parent.
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