If the service reaches the start limit, mark the sockets that activate
it as failed (with the result code 'service-broken').
This way the sockets won't act as tarpits for clients connecting to
them.
Albert Strasheim reported a socket unit with Accept=yes was failing
sometimes.
getpeername() returns ENOTCONN if the connection was killed by TCP RST.
The socket unit must not fail when it happens.
Reproducer available at:
https://bugzilla.redhat.com/show_bug.cgi?id=783344
Now that objects of all unit types are allocated the exact amount of
memory they need, the Unit union has lost its purpose. Remove it.
"Unit" is a more natural name for the base unit class than "Meta", so
rename Meta to Unit.
Access to members of the base class gets simplified.
The storage of the unit objects on the heap is currently not very
efficient. For every unit object we allocate a chunk of memory as large
as the biggest unit type, although there are significant differences in
the units' real requirements.
pahole shows the following sizes of structs:
488 Target
496 Snapshot
512 Device
528 Path
560 Timer
576 Automount
1080 Socket
1160 Swap
1168 Service
1280 Mount
Usually there aren't many targets or snapshots in the system, but Device
is one of the most common unit types and for every one we waste
1280 - 512 = 768 bytes.
Fix it by allocating only the right amount for the given unit type.
On my machine (x86_64, with 39 LVM volumes) this decreases systemd's
USS (unique set size) by more than 300 KB.
When we merge units that some kind of object points to, those pointers
might become invalidated, and needs to be updated. Introduce a UnitRef
struct which links up all the unit references, to ensure corrected
references.
At the same time, drop configured_sockets in the Service object, and
replace it by proper UNIT_TRIGGERS resp. UNIT_TRIGGERED_BY dependencies,
which allow us to simplify a lot of code.
Explicitly disconnect all clients from a VT when a getty starts/finishes
(requires TIOCVHANGUP, available in 2.6.29).
Explicitly deallocate getty VTs in order to flush scrollback buffer.
Explicitly reset terminals to a defined state before spawning getty.
Make sure that when a .socket unit is installed without its matching
.service we don't end up activating a legacy SysV/LSB service with the
same name. SysV/LSB style services do not support passing sockets and we
don't want to extend SysV/LSB to ensure we don't break compatibility
with other systems.
