To make this easier to understand, let's always log (at debug level)
when we accept or reject each device:
/swapfile: detection of swap file offset on Btrfs is not supported
/swapfile: is a candidate device.
/dev/zram0: ignoring zram swap
/dev/vdb: ignoring device with lower priority
/dev/vdc: ignoring device with lower usable space
...
If we know that hibernation will fail, refuse. This includes cases where
/sys/power/resume is set and doesn't match any device, or
/sys/power/resume_offset is set and we're not on btrfs and it doesn't match.
If /sys/power/resume is not set at all, we still accept the device with the
highest priority (see 6d176522f5 and
88bc86fcf8)
Tested cases:
1. no swap active → refuse
2. just zram swap active → refuse
3. swapfile on btrfs with /sys/power/resume{,_offset} set → OK
4. swapfile on btrfs with /sys/power/resume set, offset not set → refuse
5. swapfile on btrfs with /sys/power/resume set to nonexistent device, offset set → refuse
6. /sys/power/resume not set, offset set, candidate exists → OK (*)
7. /sys/power/resume not set, offset not set, candidate exists → OK
(*) I think this should fail, but I'm leaving that for the next commit.
Change the behavior of string arrays in a bus property map. Previously,
passing the same strv pointer to more than one map entry would result in
the old strv being freed and overwritten. With this change, an existing
strv pointer is appended to.
This is important if we want to create one strv comprised of multiple
dependencies. This makes it so callers don't have to create one strv per
dependency and subsequently merge them into one strv.
Let's use uppercase wording in the description string, like we usually
do.
Let's allow using this service in early boot.
If it's pulled into the initial transaction it's better to finish
loading this before sysinit.target.
Don't bother with this in containers that lack CAP_SYS_MODULE
Devices referred to by `DeviceAllow=` sandboxing are resolved into their
corresponding major numbers when the unit is loaded by looking at
`/proc/devices`. If a reference is made to a device which is not yet
available, the `DeviceAllow` is ignored and the unit's processes cannot
access that device.
In both logind and nspawn, we have `DeviceAllow=` lines, and `modprobe`
in `ExecStartPre=` to load some kernel modules. Those kernel modules
cause device nodes to become available when they are loaded: the device
nodes may not exist when the unit itself is loaded. This means that the
unit's processes will not be able to access the device since the
`DeviceAllow=` will have been resolved earlier and denied it.
One way to fix this would be to re-evaluate the available devices and
re-apply the policy to the cgroup, but this cannot work atomically on
cgroupsv1. So we fall back to a second approach: instead of running
`modprobe` via `ExecStartPre`, we move this out to a separate unit and
order it before the units which want the module.
Closes#14322.
Fixes: #13943.
Let's add the actual unicode names of the glyphs we use. Let's also add
in comments what the width expectations of these glyphs are on the
console.
Also, remove the "mdash" definition. First of all it wasn't used, but
what's worse the glyph encoded was actually an "ndash"...
Fixes: #14075
Previously, when first connecting to the bus after connecting to it we'd
issue a ListNames() bus call to the driver to figure out which bus names
are currently active. This information was then used to initialize the
initial state for services that use BusName=.
This change removes the whole code for this and replaces it with
something vastly simpler.
First of all, the ListNames() call was issues synchronosuly, which meant
if dbus was for some reason synchronously calling into PID1 for some
reason we'd deadlock. As it turns out there's now a good chance it does:
the nss-systemd userdb hookup means that any user dbus-daemon resolves
might result in a varlink call into PID 1, and dbus resolves quite a lot
of users while parsing its policy. My original goal was to fix this
deadlock.
But as it turns out we don't need the ListNames() call at all anymore,
since #12957 has been merged. That PR was supposed to fix a race where
asynchronous installation of bus matches would cause us missing the
initial owner of a bus name when a service is first started. It fixed it
(correctly) by enquiring with GetOwnerName() who currently owns the
name, right after installing the match. But this means whenever we start watching a bus name we anyway
issue a GetOwnerName() for it, and that means also when first connecting
to the bus we don't need to issue ListNames() anymore since that just
tells us the same info: which names are currently owned.
hence, let's drop ListNames() and instead make better use of the
GetOwnerName() result: if it failed the name is not owned.
Also, while we are at it, let's simplify the unit's owner_name_changed()
callback(): let's drop the "old_owner" argument. We never used that
besides logging, and it's hard to synthesize from just the return of a
GetOwnerName(), hence don't bother.
When a service unit watches a bus name (i.e. because of BusName= being
set), then we do two things: we install a match slot to watch how its
ownership changes, and we inquire about the current owner. Make sure we
always do both together or neither.
This in particular fixes a corner-case memleak when destroying bus
connections, since we never freed the GetNameOwner() bus slots when
destroying a bus when they were still ongoing.
It's a *return* parameter, not an input parameter. Yes, this is a bit
confusing for method call replies, but we try to use the same message
handler for all incoming messages, hence the parameter. We are supposed
to write any error into it we encounter, if we want, and our caller will
log it, but that's it.
We wait for "basic.target" being reached in the user instance anyway
before allowing the user's session to start, hence doing such a wait is
unnecessary, since that would just mean we'd wait for "default.target"
on top of "basic.target", but we shouldn#t need anything of that...
Hence, let's simplify this, reduce explicit sync points.
The name is not as universal as we want, still, hence let's use our own
user we create with sysusers.d/. That should yield same behaviour
everywhere (and also test sysusers a bit as side effect).
let's make sure we always invoke our commands through /bin/sh, since
on some distros su will use /bin/nologin (or whatever is listed in
/etc/passwd) as shell otherwise and we don#t want that.
We wait for "basic.target" being reached in the user instance anyway
before allowing the user's session to start, hence doing such a wait is
unnecessary, since that would just mean we'd wait for "default.target"
on top of "basic.target", but we shouldn#t need anything of that...
Hence, let's simplify this, reduce explicit sync points.
The name is not as universal as we want, still, hence let's use our own
user we create with sysusers.d/. That should yield same behaviour
everywhere (and also test sysusers a bit as side effect).
let's make sure we always invoke our commands through /bin/sh, since
on some distros su will use /bin/nologin (or whatever is listed in
/etc/passwd) as shell otherwise and we don#t want that.
Zbigniew Jędrzejewski-Szmek
Daniel Shahaf
Kevin Kuehler
Chris Down
Lennart Poettering
Anita Zhang
Iain Lane
Yu Watanabe
Frantisek Sumsal