This removes LOG_TARGET_SAFE. It's made redundant by the new
"prohibit-ipc" logging flag, as it used to have a similar effect: avoid
logging to the journal/syslog, i.e. any local services in order to avoid
deadlocks when we lock from PID 1 or its utility processes (such as
generators).
All previous users of LOG_TARGET_SAFE are switched over to the new
setting. This makes things a bit safer for all, as not even the
SYSTEMD_LOG_TARGET env var can be used to accidentally log to the
journal anymore in these programs.
If set, we'll avoid logging to any IPC log targets, i.e. syslog or the
journal, but allow stderr, kmsg, console logging.
This is useful as PID 1 wants to turn this off explicitly as long as the
journal is not up.
Previously we'd open/close the log stream to these services whenever
needed but this is incompatible with the "open_when_needed" logic
introduced in #6915, which might open the log streams whenever it likes,
including possibly inside of the child process we fork off that'll
become journald later on. Hence, let's make this all explicit, and
instead of managing when we open/close log streams add a boolean that
clearly prohibits the IPC targets when needed, so that opening can be
done at any time, but will honour this.
See: #7985
This doesn't matter much, and we don't rely on it, but I think it's much
nicer if we log_set_target() and log_set_upgrade_syslog_to_journal() can
be called in either order and have the same effect.
It is often the case that a file descriptor and its corresponding IO
sd_event_source share a life span. When this is the case, developers will
have to unref the event source and close the file descriptor. Instead, we
can just have the event source take ownership of the file descriptor and
close it when the event source is freed. This is especially useful when
combined with cleanup attributes and sd_event_source_unrefp().
This patch adds two new public functions:
sd_event_source_get_io_fd_own()
sd_event_source_set_io_fd_own()
The time-related functions in sd-event.h take as inputs constants (CLOCK_*)
defined in time.h. By including time.h in sd-event.h, we free the developer
from having to do this manually.
When there is a change in mac address we are not currently not changing
the MAC address and resulting v6 connectivity is gone.
When kernel reports a change in mac address change the MAC of ndisc
client too.
Closes # 7806
The left side of the || expression is conditionalized on SERVICE_START,
but SERVICE_START is blanket listed on the right side anyway, hence we
can drop the left side entirely without any change in behaviour.
Moreover, if main_pid is initialized, it should be watched, hence this
is even the safe and right thing to do.
Previously, we'd maintain two hashmaps keyed by PIDs, pointing to Unit
interested in SIGCHLD events for them. This scheme allowed a specific
PID to be watched by exactly 0, 1 or 2 units.
With this rework this is replaced by a single hashmap which is primarily
keyed by the PID and points to a Unit interested in it. However, it
optionally also keyed by the negated PID, in which case it points to a
NULL terminated array of additional Unit objects also interested. This
scheme means arbitrary numbers of Units may now watch the same PID.
Runtime and memory behaviour should not be impact by this change, as for
the common case (i.e. each PID only watched by a single unit) behaviour
stays the same, but for the uncommon case (a PID watched by more than
one unit) we only pay with a single additional memory allocation for the
array.
Why this all? Primarily, because allowing exactly two units to watch a
specific PID is not sufficient for some niche cases, as processes can
belong to more than one unit these days:
1. sd_notify() with MAINPID= can be used to attach a process from a
different cgroup to multiple units.
2. Similar, the PIDFile= setting in unit files can be used for similar
setups,
3. By creating a scope unit a main process of a service may join a
different unit, too.
4. On cgroupsv1 we frequently end up watching all processes remaining in
a scope, and if a process opens lots of scopes one after the other it
might thus end up being watch by many of them.
This patch hence removes the 2-unit-per-PID limit. It also makes a
couple of other changes, some of them quite relevant:
- manager_get_unit_by_pid() (and the bus call wrapping it) when there's
ambiguity will prefer returning the Unit the process belongs to based on
cgroup membership, and only check the watch-pids hashmap if that
fails. This change in logic is probably more in line with what people
expect and makes things more stable as each process can belong to
exactly one cgroup only.
- Every SIGCHLD event is now dispatched to all units interested in its
PID. Previously, there was some magic conditionalization: the SIGCHLD
would only be dispatched to the unit if it was only interested in a
single PID only, or the PID belonged to the control or main PID or we
didn't dispatch a signle SIGCHLD to the unit in the current event loop
iteration yet. These rules were quite arbitrary and also redundant as
the the per-unit handlers would filter the PIDs anyway a second time.
With this change we'll hence relax the rules: all we do now is
dispatch every SIGCHLD event exactly once to each unit interested in
it, and it's up to the unit to then use or ignore this. We use a
generation counter in the unit to ensure that we only invoke the unit
handler once for each event, protecting us from confusion if a unit is
both associated with a specific PID through cgroup membership and
through the "watch_pids" logic. It also protects us from being
confused if the "watch_pids" hashmap is altered while we are
dispatching to it (which is a very likely case).
- sd_notify() message dispatching has been reworked to be very similar
to SIGCHLD handling now. A generation counter is used for dispatching
as well.
This also adds a new test that validates that "watch_pid" registration
and unregstration works correctly.
This code is very similar in scope and service units, let's unify it in
one function. This changes little for service units, but for scope units
makes sure we go through the cgroup queue, which is something we should
do anyway.
Let's send them out only if the main or control processe exited and we
recorded a new exit status that is worth reporting. But if any other
service process died this is nothing to report since we don't expose any
properties about that anyway.
Previously, we'd hard map PID 1 to the manager scope unit. That's wrong
however when we are run in --user mode, as the PID 1 is outside of the
subtree we manage and the manager PID might be very differently. Correct
that by checking for getpid() rather than hardcoding 1.
Currently, we create leading directories implicitly for all lines that
create directory or directory-like nodes.
With this, we also do the same for a number of other lines: f/F, C, p,
L, c/b (that is regular files, pipes, symlinks, device nodes as well as
file trees we copy).
The leading directories are created with te default access mode of 0755.
If something else is desired, users should simply declare appropriate
"d" lines.
Fixes: #7853
Before this patch, we'd treat clone_device_node() returning 0 (as
opposed to 1) as error, but then propagate this non-error result in
confusion.
This makes sure that if we ptmx isn't around we propagate that as
-ENXIO.
This is a follow-up for 98b1d2b8d9
This fundamentally makes one change: we never process more than one
signal or more than one waitid() event per event loop. We'll never tight
loop around waitid() or around read() on our signalfd instead, but
always return to the main event loop after processing one event.
By doing this we put the event priorization handling into full power
again, as we'll always check for higher priority events before looking
at the next signal or waitid() again.
This introduces a new "defer" event source "sigchld_event". It's enabled
as soon as we see SIGCHLD, and disabled as soon as waitid() reported no
further children pending. It's running at a relatively high priority,
one step higher than signal handling itself, but lower than
/proc/self/mountinfo event handling, so that the latter always takes
precedence.
Since we want to process sd_notify() events at an even higher priority
than SIGCHLD (as before) it is moved one priority step up, too.
Fixes: #7932
Possibly fixes: #7966
