This adds three kinds of file system locks for container images:
a) a file system lock next to the actual image, in a .lck file in the
same directory the image is located. This lock has the benefit of
usually being located on the same NFS share as the image itself, and
thus allows locking container images across NFS shares.
b) a file system lock in /run, named after st_dev and st_ino of the
root of the image. This lock has the advantage that it is unique even
if the same image is bind mounted to two different places at the same
time, as the ino/dev stays constant for them.
c) a file system lock that is only taken when a new disk image is about
to be created, that ensures that checking whether the name is already
used across the search path, and actually placing the image is not
interrupted by other code taking the name.
a + b are read-write locks. When a container is booted in read-only mode
a read lock is taken, otherwise a write lock.
Lock b is always taken after a, to avoid ABBA problems.
Lock c is mostly relevant when renaming or cloning images.
Now that networkd's IP masquerading support means that running
containers with "--network-veth" will provide network access out of the
box for the container, let's add a shortcut "-n" for it, to make it
easily accessible.
It does not use any functions from libcap directly. The CAP_* constants in use
through this file come from "missing.h" which will import <linux/capability.h>
and complement it with CAP_* constants not defined by the current kernel
headers.
Add an explicit import of our "capability.h" since it does use the function
capability_bounding_set_drop from that header file. Previously, that header was
implicitly imported through through "cap-list.h".
Tested that "systemd-nspawn" builds cleanly and works after this change.
Also, when booting up an ephemeral container of / use the system
hostname as default machine name.
This way specifiyng -M is unnecessary when booting up an ephemeral
container, while allowing any number of ephemeral containers to run from
the same tree.
This works now:
# systemd-nspawn -xb -D / -M foobar
Which boots up an ephemeral container, based on the host's root file
system. Or in other words: you can now run the very same host OS you
booted your system with also in a container, on top of it, without
having it interfere. Great for testing whether the init system you are
hacking on still boots without reboot the system!
This adds --template= to duplicate an OS tree as btrfs snpashot and run
it
This also adds --ephemeral or -x to create a snapshot of an OS tree and
boot that, removing it after exit.
If the format string contains %m, clearly errno must have a meaningful
value, so we might as well use log_*_errno to have ERRNO= logged.
Using:
find . -name '*.[ch]' | xargs sed -r -i -e \
's/log_(debug|info|notice|warning|error|emergency)\((".*%m.*")/log_\1_errno(errno, \2/'
Plus some whitespace, linewrap, and indent adjustments.
Using:
find . -name '*.[ch]' | while read f; do perl -i.mmm -e \
'local $/;
local $_=<>;
s/(if\s*\([^\n]+\))\s*{\n(\s*)(log_[a-z_]*_errno\(\s*([->a-zA-Z_]+)\s*,[^;]+);\s*return\s+\g4;\s+}/\1\n\2return \3;/msg;
print;'
$f
done
And a couple of manual whitespace fixups.
As a followup to 086891e5c1 "log: add an "error" parameter to all
low-level logging calls and intrdouce log_error_errno() as log calls
that take error numbers", use sed to convert the simple cases to use
the new macros:
find . -name '*.[ch]' | xargs sed -r -i -e \
's/log_(debug|info|notice|warning|error|emergency)\("(.*)%s"(.*), strerror\(-([a-zA-Z_]+)\)\);/log_\1_errno(-\4, "\2%m"\3);/'
Multi-line log_*() invocations are not covered.
And we also should add log_unit_*_errno().
commit 79d80fc146 introduced a regression that
prevents mounting a tmpfs if the mount point already exits in the container's
root file system. This commit fixes the problem by ignoring EEXIST.
--link-journal={host,guest} fail if the host does not have persistent
journalling enabled and /var/log/journal/ does not exist. Even worse, as there
is no stdout/err any more, there is no error message to point that out.
Introduce two new modes "try-host" and "try-guest" which don't fail in this
case, and instead just silently skip the guest journal setup.
Change -j to mean "try-guest" instead of "guest", and fix the wrong --help
output for it (it said "host" before).
Change systemd-nspawn@.service.in to use "try-guest" so that this unit works
with both persistent and non-persistent journals on the host without failing.
https://bugs.debian.org/770275
kdbus has seen a larger update than expected lately, most notably with
kdbusfs, a file system to expose the kdbus control files:
* Each time a file system of this type is mounted, a new kdbus
domain is created.
* The layout inside each mount point is the same as before, except
that domains are not hierarchically nested anymore.
* Domains are therefore also unnamed now.
* Unmounting a kdbusfs will automatically also detroy the
associated domain.
* Hence, the action of creating a kdbus domain is now as
privileged as mounting a filesystem.
* This way, we can get around creating dev nodes for everything,
which is last but not least something that is not limited by
20-bit minor numbers.
The kdbus specific bits in nspawn have all been dropped now, as nspawn
can rely on the container OS to set up its own kdbus domain, simply by
mounting a new instance.
A new set of mounts has been added to mount things *after* the kernel
modules have been loaded. For now, only kdbus is in this set, which is
invoked with mount_setup_late().
The barrier implementation tracks remote states internally. There is no
need to check the return value of any barrier_*() function if the caller
is not interested in the result. The barrier helpers only return the state
of the remote side, which is usually not interesting as later calls to
barrier_sync() will catch this, anyway.
Shut up coverity by explicitly ignoring return values of barrier_place()
if we're not interested in it.
A combination of commits f3c80515c and 79d80fc14 cause nspawn to
silently fail with a commandline such as:
# systemd-nspawn -D /build/extra-x86_64 --bind=/usr
strace shows the culprit:
[pid 27868] writev(2, [{"Failed to create mount point /build/extra-x86_64/usr: File exists", 82}, {"\n", 1}], 2) = 83
Function queries system hostname and applies changes only when necessary. Also,
migrate all client of sethostname to sethostname_idempotent while at it.
Commit 864e17068 ("nspawn: actually allow access to /dev/net/tun in the
container") added "/dev/net/tun" to the list of allowed devices but forgot
to tweak the array length, which caused "/dev/kdbus/*" to be missed.
