- In a PF_LOCAL address, "hostname" must begins with '/' and "servname"
is always NULL. All of ai_flags are ignored.
- PF_UNSPEC matches PF_LOCAL. EAI_SERVICE is not returned to make
AF-independent programming easier; "servname" is always ignored
in PF_LOCAL. In practice, PF_INET* and PF_LOCAL are
mutually-exclusive because a hostname which begins with '/' is invalid
in PF_INET*. No domain name resolution is performed for a PF_LOCAL address.
Differential Revision: https://reviews.freebsd.org/D3634
Note that the mountlist manipulations are somewhat fragile, and not very
pretty. The reason for this is to avoid changing vfs_mountroot(), which
is (obviously) rather mission-critical, but not very well documented,
and thus hard to test properly. It might be possible to rework it to use
its own simple root mount mechanism instead of vfs_mountroot().
Reviewed by: kib@
MFC after: 1 month
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D2698
This silence a warning brought up by valgrind whenever if_nametoindex
is used. This was already discussed in PR 166483, but the code
committed in r234329 guards the initilization with #ifdef PURIFY.
Therefore, valgrind still complains. Since this code is not performance
critical, always zero out the local variable to silence valgrind.
PR: 166483
Discussed with: eadler@
MFC after: 4 weeks
calling thread is supposed to see accesses issued by the initializer.
This means that the read of the once_control->state variable should
have an acquire semantic. Use atomic_thread_fence_acq() when the
value read is ONCE_DONE, instead of straightforward atomic_load_acq(),
to only put a barrier when needed (*).
On the other hand, the updates of the once_control->state with the
intermediate progress state do not need to synchronize with other
state accesses, remove _acq suffix.
Reviewed by: alc (previous version)
Suggested by: alc (*)
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Coredump notes depend on being able to invoke dump routines twice; once
in a dry-run mode to get the size of the note, and another to actually
emit the note to the corefile.
When a note helper emits a different length section the second time
around than the length it requested the first time, the kernel produces
a corrupt coredump.
NT_PROCSTAT_FILES output length, when packing kinfo structs, is tied to
the length of filenames corresponding to vnodes in the process' fd table
via vn_fullpath. As vnodes may move around during dump, this is racy.
So:
- Detect badly behaved notes in putnote() and pad underfilled notes.
- Add a fail point, debug.fail_point.fill_kinfo_vnode__random_path to
exercise the NT_PROCSTAT_FILES corruption. It simply picks random
lengths to expand or truncate paths to in fo_fill_kinfo_vnode().
- Add a sysctl, kern.coredump_pack_fileinfo, to allow users to
disable kinfo packing for PROCSTAT_FILES notes. This should avoid
both FILES note corruption and truncation, even if filenames change,
at the cost of about 1 kiB in padding bloat per open fd. Document
the new sysctl in core.5.
- Fix note_procstat_files to self-limit in the 2nd pass. Since
sometimes this will result in a short write, pad up to our advertised
size. This addresses note corruption, at the risk of sometimes
truncating the last several fd info entries.
- Fix NT_PROCSTAT_FILES consumers libutil and libprocstat to grok the
zero padding.
With suggestions from: bjk, jhb, kib, wblock
Approved by: markj (mentor)
Relnotes: yes
Sponsored by: EMC / Isilon Storage Division
Differential Revision: https://reviews.freebsd.org/D3548
