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author | kib <kib@FreeBSD.org> | 2014-08-07 05:47:53 +0000 |
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committer | kib <kib@FreeBSD.org> | 2014-08-07 05:47:53 +0000 |
commit | 0b059d23c7081e1cea5512459c573223dc017be9 (patch) | |
tree | 033a19954132b23984c24a614f928220b364cc2b /sys/kern/sys_process.c | |
parent | ffe6b11ba6dedd5eff6feb31b9e53c526bf6c5dd (diff) | |
download | FreeBSD-src-0b059d23c7081e1cea5512459c573223dc017be9.zip FreeBSD-src-0b059d23c7081e1cea5512459c573223dc017be9.tar.gz |
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).
Phabric: D417
Reviewed by: jhb
Tested by: pho
Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks
Diffstat (limited to 'sys/kern/sys_process.c')
-rw-r--r-- | sys/kern/sys_process.c | 10 |
1 files changed, 1 insertions, 9 deletions
diff --git a/sys/kern/sys_process.c b/sys/kern/sys_process.c index 821c779..b30e12a 100644 --- a/sys/kern/sys_process.c +++ b/sys/kern/sys_process.c @@ -917,19 +917,11 @@ kern_ptrace(struct thread *td, int req, pid_t pid, void *addr, int data) case PT_DETACH: /* reset process parent */ if (p->p_oppid != p->p_pptr->p_pid) { - struct proc *pp; - PROC_LOCK(p->p_pptr); sigqueue_take(p->p_ksi); PROC_UNLOCK(p->p_pptr); - PROC_UNLOCK(p); - pp = pfind(p->p_oppid); - if (pp == NULL) - pp = initproc; - else - PROC_UNLOCK(pp); - PROC_LOCK(p); + pp = proc_realparent(p); proc_reparent(p, pp); if (pp == initproc) p->p_sigparent = SIGCHLD; |