systemd-sysusers is a tool to reconstruct /etc/passwd and /etc/group
from static definition files that take a lot of inspiration from
tmpfiles snippets. These snippets should carry information about system
users only. To make sure it is not misused for normal users these
snippets only allow configuring UID and gecos field for each user, but
do not allow configuration of the home directory or shell, which is
necessary for real login users.
The purpose of this tool is to enable state-less systems that can
populate /etc with the minimal files necessary, solely from static data
in /usr. systemd-sysuser is additive only, and will never override
existing users.
This tool will create these files directly, and not via some user
database abtsraction layer. This is appropriate as this tool is supposed
to run really early at boot, and is only useful for creating system
users, and system users cannot be stored in remote databases anyway.
The tool is also useful to be invoked from RPM scriptlets, instead of
useradd. This allows moving from imperative user descriptions in RPM to
declarative descriptions.
The UID/GID for a user/group to be created can either be chosen dynamic,
or fixed, or be read from the owner of a file in the file system, in
order to support reconstructing the correct IDs for files that shall be
owned by them.
This also adds a minimal user definition file, that should be
sufficient for most basic systems. Distributions are expected to patch
these files and augment the contents, for example with fixed UIDs for
the users where that's necessary.
network-pre.target is a passive target that should be pulled in by
services that want to be executed before any network is configured (for
example: firewall scrips).
network-pre.target should be ordered before all network managemet
services (but not be pulled in by them).
network-pre.target should be order after all services that want to be
executed before any network is configured (and be pulled in by them).
Reuses logic from service.c and the rc-local generator.
Note that this drops reading of chkconfig entirely. It also drops reading
runlevels from the LSB headers. The runlevels were only used to check for
runlevels outside of the normal 1-5 range and then add special dependencies
and settings. Special runlevels were dropped in the past so it seemed to be
unused code.
The generator does not know about non-generated units with a value set with
SysVStartPriority=. These are therefor not taken into account when converting
start priority to before/after.
Either become uid/gid of the client we have been forked for, or become
the "systemd-bus-proxy" user if the client was root. We retain
CAP_IPC_OWNER so that we can tell kdbus we are actually our own client.
Rely on modules being built-in or autoloaded on-demand.
As networkd is a network facing service, we want to limits its capabilities,
as much as possible. Also, we may not have CAP_SYS_MODULE in a container,
and we want networkd to work the same there.
Module autoloading does not always work, but should be fixed by the kernel
patch f98f89a0104454f35a: 'net: tunnels - enable module autoloading', which
is currently in net-next and which people may consider backporting if they
want tunneling support without compiling in the modules.
Early adopters may also use a module-load.d snippet and order
systemd-modules-load.service before networkd to force the module
loading of tunneling modules.
This sholud fix the various build issues people have reported.
This allows us to run networkd mostly unpriviliged with the exception of
CAP_NET_* and CAP_SYS_MODULE. I'd really like to get rid of the latter
though...
Instead of accessing /proc/1/environ directly, trying to read the
$container variable from it, let's make PID 1 save the contents of that
variable to /run/systemd/container. This allows us to detect containers
without the need for CAP_SYS_PTRACE, which allows us to drop it from a
number of daemons and from the file capabilities of systemd-detect-virt.
Also, don't consider chroot a container technology anymore. After all,
we don't consider file system namespaces container technology anymore,
and hence chroot() should be considered a container even less.
nspawn and the container child use eventfd to wait and notify each other
that they are ready so the container setup can be completed.
However in its current form the wait/notify event ignore errors that
may especially affect the child (container).
On errors the child will jump to the "child_fail" label and terminate
with _exit(EXIT_FAILURE) without notifying the parent. Since the eventfd
is created without the "EFD_NONBLOCK" flag, this leaves the parent
blocking on the eventfd_read() call. The container can also be killed
at any moment before execv() and the parent will not receive
notifications.
We can fix this by using cheap mechanisms, the new high level eventfd
API and handle SIGCHLD signals:
* Keep the cheap eventfd and EFD_NONBLOCK flag.
* Introduce eventfd states for parent and child to sync.
Child notifies parent with EVENTFD_CHILD_SUCCEEDED on success or
EVENTFD_CHILD_FAILED on failure and before _exit(). This prevents the
parent from waiting on an event that will never come.
* If the child is killed before execv() or before notifying the parent,
we install a NOP handler for SIGCHLD which will interrupt blocking calls
with EINTR. This gives a chance to the parent to call wait() and
terminate in main().
* If there are no errors, parent will block SIGCHLD, restore default
handler and notify child which will do execv(), then parent will pass
control to process_pty() to do its magic.
This was exposed in part by:
https://bugs.freedesktop.org/show_bug.cgi?id=76193
Reported-by: Tobias Hunger tobias.hunger@gmail.com
On Thu, May 22, 2014 at 9:53 AM, Jan Engelhardt <jengelh@inai.de> wrote:
>
> If libsystemd-network.la is relying on that udev function, it ought
> to specify libudev(-internal).la in libsystemd_network_la_LIBADD.
The verbose link-time deprecation warnings are annoying. These libs
will never change or be extended; there is no need to test the list
of exported symbols.
./.libs/libsystemd-network.a(libsystemd_network_la-network-internal.o):
network-internal.c:function net_get_unique_predictable_data:
error: undefined reference to 'udev_device_get_property_value'
collect2: error: ld returned 1 exit status
We shouldn't destroy IPC objects of system users on logout.
http://lists.freedesktop.org/archives/systemd-devel/2014-April/018373.html
This introduces SYSTEM_UID_MAX defined to the maximum UID of system
users. This value is determined compile-time, either as configure switch
or from /etc/login.defs. (We don't read that file at runtime, since this
is really a choice for a system builder, not the end user.)
While we are at it we then also update journald to use SYSTEM_UID_MAX
when we decide whether to split out log data for a specific client.
This makes callback behaviour more like sd-event or sd-resolve, and
creates proper object for unregistering callbacks.
Taking the refernce to the slot is optional. If not taken life time of
the slot will be bound to the underlying bus object (or in the case of
an async call until the reply has been recieved).
New "struct ring" object that implements a basic ring buffer for arbitrary
byte-streams. A new basic runtime test is also added.
This will be needed for our pty helpers for systemd-console and friends.
As the operational state detection in sd-network is still too primitive, timesyncd
will likely try to connect a bit early, so the first attempt will fail.
- Also only allow positive ifindex on both dhcp and ipv4ll
[tomegun: the kernel always sets a positive ifindex, but some APIs accept
ifindex=0 with various meanings, so we should protect against
accidentally passing ifindex=0 along.]
To make sure we don't delay boot on systems where (some) network links are managed by someone else
we don't block if something else has successfully brought up a link.
We will still block until all links we are aware of that are managed by networkd have been
configured, but if no such links exist, and someone else have configured a link sufficiently
that it has a carrier, it may be that the link is ready so we should no longer block.
Note that in all likelyhood the link is not ready (no addresses/routes configured),
so whatever network managment daemon configured it should provide a similar wait-online
service to block network-online.target until it is ready.
The aim is to block as long as we know networking is not fully configured, but no longer. This
will allow systemd-networkd-wait-online.service to be enabled on any system, even if we don't
know whether networkd is the main/only network manager.
Even in the case networking is fully configured by networkd, the default behavior may not be
sufficient: if two links need to be configured, but the first is fully configured before the
second one appears we will assume the network is up. To work around that, we allow specifying
specific devices to wait for before considering the network up.
This unit is enabled by default, just like systemd-networkd, but will only be pulled in if
anyone pulls in network-online.target.
Lennart Poettering