This makes most header files easier to look at. Also Emacs gets really
slow when browsing through large sections of overly long prototypes,
which is much improved by this macro.
We should probably not do something similar with too many other cases,
as macros like this might help readability for some, but make it worse
for others. But I think given the complexity of this specific prototype
and how often we use it, it's worth doing.
The use of UINT64_C() in the SettingsMask enum definition is misleading:
it does not mean that individual fields have this width. E.g., with
enum {
FOO = UINT64_C(1)
}
sizeof(FOO) gives 4. It only means that the shift is done properly. So
1 << 35 is undefined, but UINT64_C(1) << 35 is the expected 64 bit
constant. Thus, the use UINT64_C() is useful, because we know that the shifts
are done properly, no matter what the value of _RLIMIT_MAX is, but when those
fields are used in expressions, we don't know what size they will be
(probably 4). Let's add a define which "hides" the enum definition behind a
define which gives the same value but is actually 64 bit. I think this is a
nicer solution than requiring all users to cast SETTING_RLIMIT_FIRST before
use.
Fixes#9035.
Let's separate the loading of the settings object and the merging into
our arg_xyz fields into two.
This will become particularly useful when we eventually are able to load
settings from OCI runtime files in addition to .nspawn files.
Similar as the other options added before, this is primarily useful to
provide comprehensive OCI runtime compatbility, but might be useful
otherwise, too.
This simply controls the PR_SET_NO_NEW_PRIVS flag for the container.
This too is primarily relevant to provide OCI runtime compaitiblity, but
might have other uses too, in particular as it nicely complements the
existing --capability= and --drop-capability= flags.
Previously, the container's hostname was exclusively initialized from
the machine name configured with --machine=, i.e. the internal name and
the external name used for and by the container was synchronized. This
adds a new option --hostname= that optionally allows the internal name
to deviate from the external name.
This new option is mainly useful to ultimately implement the OCI runtime
spec directly in nspawn, but it might be useful on its own for some
other usecases too.
This ensures we set the various resource limits of our container
explicitly on each invocation so that we inherit less from our callers
into the payload.
By default resource limits are now set to the same values Linux
generally passes to the host PID 1, thus minimizing needless differences
between host and container environments.
The limits are now also configurable using a new --rlimit= switch. This
is preparation for teaching nspawn native OCI runtime support as OCI
permits setting resource limits for container payloads, and it hence
probably makes sense if we do too.
We need to do this in all cases, including on cgroupsv1 in order to
ensure the host systemd and any systemd in the payload won't fight for
the cgroup attributes of the top-level cgroup of the payload.
This is because systemd for Delegate=yes units will only delegate the
right to create children as well as their attributes. However, nspawn
expects that the cgroup delegated covers both the right to create
children and the attributes of the cgroup itself. Hence, to clear this
up, let's unconditionally insert a intermediary cgroup, on cgroupsv1 as
well as cgroupsv2, unconditionally.
This is also nice as it reduces the differences in the various setups
and exposes very close behaviour everywhere.
Let's not make /run too special and let's make sure the source file is
not guessable: let's use our regular temporary file helper calls to
create the source node.
This tightens security on /proc: a couple of files exposed there are now
made inaccessible. These files might potentially leak kernel internals
or expose non-virtualized concepts, hence lock them down by default.
Moreover, a couple of dirs in /proc that expose stuff also exposed in
/sys are now marked read-only, similar to how we handle /sys.
The list is taken from what docker/runc based container managers
generally apply, but slightly extended.
This drops a good number of type-specific _cleanup_ macros, and patches
all users to just use the generic ones.
In most recent code we abstained from defining type-specific macros, and
this basically removes all those added already, with the exception of
the really low-level ones.
Having explicit macros for this is not too useful, as the expression
without the extra macro is generally just 2ch wider. We should generally
emphesize generic code, unless there are really good reasons for
specific code, hence let's follow this in this case too.
Note that _cleanup_free_ and similar really low-level, libc'ish, Linux
API'ish macros continue to be defined, only the really high-level OO
ones are dropped. From now on this should really be the rule: for really
low-level stuff, such as memory allocation, fd handling and so one, go
ahead and define explicit per-type macros, but for high-level, specific
program code, just use the generic _cleanup_() macro directly, in order
to keep things simple and as readable as possible for the uninitiated.
Note that before this patch some of the APIs (notable libudev ones) were
already used with the high-level macros at some places and with the
generic _cleanup_ macro at others. With this patch we hence unify on the
latter.
We don't know what the container payload needs, hence default to a PATH
with both bin and sbin included, as well as / and /usr.
Follow-up for #8324Fixes: #8698
Double newlines (i.e. one empty lines) are great to structure code. But
let's avoid triple newlines (i.e. two empty lines), quadruple newlines,
quintuple newlines, …, that's just spurious whitespace.
It's an easy way to drop 121 lines of code, and keeps the coding style
of our sources a bit tigther.
Files which are installed as-is (any .service and other unit files, .conf
files, .policy files, etc), are left as is. My assumption is that SPDX
identifiers are not yet that well known, so it's better to retain the
extended header to avoid any doubt.
I also kept any copyright lines. We can probably remove them, but it'd nice to
obtain explicit acks from all involved authors before doing that.
Otherwise, network interfaces can be "moved" into the container's
namespace while it's still the same as the host namespace, in which case
e.g. host0 for a veth ends up on the host side instead of inside the
container.
Regression introduced in 0441378080.
Fixes#8599.
When we are attempting to create directory somewhere in the bowels of /var/lib
and get an error that it already exists, it can be quite hard to diagnose what
is wrong (especially for a user who is not aware that the directory must have
the specified owner, and permissions not looser than what was requested). Let's
print a warning in most cases. A warning is appropriate, because such state is
usually a sign of borked installation and needs to be resolved by the adminstrator.
$ build/test-fs-util
Path "/tmp/test-readlink_and_make_absolute" already exists and is not a directory, refusing.
(or)
Directory "/tmp/test-readlink_and_make_absolute" already exists, but has mode 0775 that is too permissive (0755 was requested), refusing.
(or)
Directory "/tmp/test-readlink_and_make_absolute" already exists, but is owned by 1001:1000 (1000:1000 was requested), refusing.
Assertion 'mkdir_safe(tempdir, 0755, getuid(), getgid(), MKDIR_WARN_MODE) >= 0' failed at ../src/test/test-fs-util.c:320, function test_readlink_and_make_absolute(). Aborting.
No functional change except for the new log lines.
This macro will read a pointer of any type, return it, and set the
pointer to NULL. This is useful as an explicit concept of passing
ownership of a memory area between pointers.
This takes inspiration from Rust:
https://doc.rust-lang.org/std/option/enum.Option.html#method.take
and was suggested by Alan Jenkins (@sourcejedi).
It drops ~160 lines of code from our codebase, which makes me like it.
Also, I think it clarifies passing of ownership, and thus helps
readability a bit (at least for the initiated who know the new macro)
The warning is not emitted for absolute paths like /dev/sda or /home, which are
converted to .device and .mount unit names without any fuss.
Most of the time it's unlikely that users use invalid unit names on purpose,
so let's warn them. Warnings are silenced when --quiet is used.
$ build/systemctl show -p Id hello@foo-bar/baz
Invalid unit name "hello@foo-bar/baz" was escaped as "hello@foo-bar-baz" (maybe you should use systemd-escape?)
Id=hello@foo-bar-baz.service
$ build/systemd-run --user --slice foo-bar/baz --unit foo-bar/foo true
Invalid unit name "foo-bar/foo" was escaped as "foo-bar-foo" (maybe you should use systemd-escape?)
Invalid unit name "foo-bar/baz" was escaped as "foo-bar-baz" (maybe you should use systemd-escape?)
Running as unit: foo-bar-foo.service
Fixes#8302.
At various places we only want to close fds if they are not
stdin/stdout/stderr, i.e. fds 0, 1, 2. Let's add a unified helper call
for that, and port everything over.
There isn't much difference, but in general we prefer to use the standard
functions. glibc provides reallocarray since version 2.26.
I moved explicit_bzero is configure test to the bottom, so that the two stdlib
functions are at the bottom.
Lennart Poettering
Arnaud Rebillout
Zbigniew Jędrzejewski-Szmek
Yu Watanabe
Philip Sequeira