The current behaviour of the kernel to deadlock itself
instead of returning an error on fork.
This might change in the future, so prepare libthread
to handle this case.
For _schedfork(), we'r going to just retry forking
on every switch, while for _schedexec(), the exec
will fail and send ~0 down the pid channel.
The ipoput4() and ipoput6() functions can raise an error(),
which means before calling sndrst() or limbo() (from tcpiput()),
we have to get rid of our blist by calling freeblist(bp).
Makse sure to set the Block pointer to nil after freeing in
ipiput() to avoid accidents.
Fix wrong panic string in sndsynack, and make any sending
functions like sndrst(), sndsynack() and tcpsendka()
return the value of ipoput*(), so we can distinguish
"no route" error.
Add a Enoroute[] string constant.
Both htontcp4() and htontcp6() can never return nil,
as they will allocate new or resize the existing block.
Remove the misleading error handling code that assumes
that it can fail.
Unlock proto on error in limborexmit() which can
be raised from sndsynack() -> ipoput*() -> error().
Make sndsynack() pass a Routehint pointer to ipoput*()
as it already did the route lookup, so we dont have todo
it twice.
i'm not confident about mutating the route tree
pointers and have concurrent readers walking the
pointer chains.
given that most route lookups are bypassed now
for non-routing case and we are not building a
high performance router here, lets play it safe.
theres no structure in the lower 32 bits of an ipv6 address.
use the top bit to distinguish special stuff like multicast
and link-local addresses, and use the 16-bit subnet-id bits
for the rest.
Instead of having to do an arp hash table lookup for each
outgoing ip packet, forward the Routehint pointer to the
medium's bwrite() function and let it cache the arp entry
pointer.
This avoids route and arp hash table lookups for tcp, il
and connection oriented udp.
It also allows us to avoid multiple route and arp table
lookups for the retransmits once an arp/neighbour solicitation
response arrives.
The Mhead structures have two sources of references to them:
- from Pgrp.mnthash hash-table
- from a channels Chan.umh pointer as returned by namec() for a union directory
Unless one holds the Mhead.lock RWLock, the Mhead.mount chain
can be mutated by eigther cmount(), cunmount() or closepgrp().
Readers, skipping acquiering the lock where:
mountfix(): responsible for rewriting directory entries for
union directory reads; was walking the Mhead.mount chain to
detect if the passed channel itself appears in the mount list.
cmount(): had a check and copy when "new" chan was a union itself
and if the MCREATE flag is set and would copy the mount table.
All this needs to be done with Mhead read-locked while copying
the mount entries.
devproc(): in the handler for reading /proc/n/ns file.
namec(): while checking if the Chan->umh should be initialized.
In addition to this, cmount() is changed to do the mountfree()
of the original mount chain when MREPL is done after releasing
the locks.
Also, some cosmetic changes...
The IPv4 ARP cache used to indefinitely buffer packets in the Arpent hold list.
This is bad in case of a router, because it opens a 1 second
(retransmit time) window to leak all the to be forwarded packets.
This change makes the ipv4 arp code path similar to the IPv6 neighbour
solicitation path, using the retransmit process to time out old entries
(after 3 arp retransmits => 3 seconds).
A new function arpcontinue() has been added that unifies the point when
we schedule the (ipv6 sol retransmit) / (ipv4 arp timeout) and reduce
the hold queue to the last packet and unlock the cache.
As a bonus, we also now send a icmp host unreachable notification
for the dropped packets.
tlsbwrite() would call checkstate() before calling tlsrecwrite()
to make sure the channel is open. however, because checkstate()
only raises the error, the Block* passed wont be freed and
would result in a memory leak.
move the checkstate() call inside tlsrecwrite() to reuse the
error handling that frees the block on error.
in OpenBSD 6.9 and up, the kernel (bsd, bsd.mp) still has
the ostype symbols, but bsd.rd appears to have lost them,
even when decompressed.
so, as a result, we should use what we have, which isn't
much.
Due to the way LCA is defined, a using a strict LCA
on a graph like this:
<--a--b--c--d--e--f--g
\ /
+-----h-------
can lead to spurious requests to merge. This happens
because 'lca(b, g)' would return 'a', since it can be
reached in one step from 'b', and 2 steps from 'g', while
reaching 'b' from 'a' would be a longer path.
As a result, we need to implement an lca variant that
returns the starting node if one is reachable from the
other, even if it's already found the technically correct
least common ancestor.
This replaces our LCA algorithm with one based on the
painting we do while finding a twixt, making it give
the resutls we want.
git/query: fix spurious merge requests
Due to the way LCA is defined, a using a strict LCA
on a graph like this:
<--a--b--c--d--e--f--g
\ /
+-----h-------
can lead to spurious requests to merge. This happens
because 'lca(b, g)' would return 'a', since it can be
reached in one step from 'b', and 2 steps from 'g', while
reaching 'b' from 'a' would be a longer path.
As a result, we need to implement an lca variant that
returns the starting node if one is reachable from the
other, even if it's already found the technically correct
least common ancestor.
This replaces our LCA algorithm with one based on the
painting we do while finding a twixt.
directory entries cannot span sector boundaries, meaning
that the end of a sector would be zero padded until the
next sector.
we have to skip over these zero paddings to fully read
the directory.
Plumber both posts a service to /srv and sets a $plumbsrv environment
variable. Our libplumb no longer uses $plumbsrv and nothing else
does. It's a silly hack; rc doesn't update /env immediately, and
scripts, which for instance set up subrios, cannot rely on it to
clean up the plumber at the end.
Instead, add the option to specify a srvname, actually check for some
common errors and print a usage string.
Thanks to Ori for input and a preliminary patch.
- enforce same behaviour as cachedb server in dblookup():
- force Taaaa record type on ipv6= attributes, regardless of value
- return Taaaa records for ip= attributes containing ipv6 values
- return Ta records only for ip= attributes containing ipv4 values
- for compatibility, bring back support for txtrr= type, but handle consistently
Git has the ability to track the person who
creates a commit separately from the person
who wrote the commit. For git9, we ignored
this feature.
However, as we start using git/import more,
it will be useful to figure out who imported
a commit, as well as who wrote it.
This change adds support for seeing this
information in git, as well as setting the
author and committer separately in git/import.
Target generation is revised, split into $YTARG and $TARG.
$PROGS is inlined to the cmd target.
%.cpus is added to allow chaining: mk all.cpus
$POWERLESS is added, since dtracy doesn't build yet on ppc.
$DIRS regexp is simplified, simplifing $NOMK.
$cpuobjtype is replaced with cp's recipe for copying itself on $cputype.
$APEDIRS is removed.
The none target is renamed to usage, since it prints out usage.
The ape target is removed.
The dirs target is replaced by all.dirs
%.directories is replaced by %.dirs
The all target serializes directories after cmds to match the install target recipe.
All regexp rules are replaced with nonregexp versions for clarity.
The &:n: rule is removed. Just build the $O.$cmd file.
.y files now build .c files, not .tab.c files, and remove (bc|units|mpc|pc).c:R:
All safeinstall rules are removed.
The cleanfiles rule is renamed to cleancmds and simplified.
%.clean is removed. Just use mk cleancmds.
The install rule serializes cp and yacc before building anything else, avoiding races.
The installall recipe is simplified with the install.cpus prereq.
%.installall is removed. Just use mk $cmd.install.cpus
The $O.cj, %.update, and compilers rules are removed.
openssh now disables RSA/SHA-1 by default, so using RSA/SHA-1 will
eventually cause us problems:
https://undeadly.org/cgi?action=article;sid=20210830113413
in addition, github will disable RSA/SHA-1 for recently added RSA keys:
https://github.blog/2021-09-01-improving-git-protocol-security-github/
this patch modifies ssh.c to use RSA/SHA-256 (aka rsa-sha2-256)
instead of RSA/SHA-1 (aka ssh-rsa) as the public key algorithm.
NOTE: public rsa keys and thumbprints are ***NOT AFFECTED***
by this patch.
while we're here, remove the workaround for github.com. it seems
that github has fixed their implementation, and does not look into
macalgs when we're using an aead cipher.
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