half of find_hibernation_location() logged at debug level, the other
half logged at error level, and the third half didn't log at all.
Let's clean this up somewhat. Since can_sleep() is probably more
a library-style function let's downgrade everything to LOG_DEBUG and
then make sure sleep.c logs at error level, as the main program.
This is a follow-up for 9f83091e3c.
Instead of reading the mtime off the configuration files after reading,
let's do so before reading, but with the fd we read the data from. This
is not only cleaner (as it allows us to save one stat()), but also has
the benefit that we'll detect changes that happen while we read the
files.
This also reworks unit file drop-ins to use the common code for
determining drop-in mtime, instead of reading system clock for that.
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.
When calculation of swap file offset is unsupported, rely on the
/sys/power/resume & /sys/power/resume_offset values if configured
rather than requiring a matching swap entry to be identified.
Refactor to use dev_t for comparison of resume= device instead of string.
We were looking at the wrong variable, and would always crash if this
comparison was reached. Fixes#13965.
Also, fix crash (_cleanup_ called on uninitialized variable) if we failed in
error path.
While at it, let's shorten some messages.
This change checks each swap partition or file reported in /proc/swaps
to see if it matches the values configured with resume= and
resume_offset= kernel parameters. If a match is found, the matching swap
entry is used as the hibernation location regardless of swap priority.
In situations where hibernation is requested but resume= and
resume_offset= kernel parameters are not configured, systemd
will attempt to locate a suitable swap location by inspecting
/proc/swaps. This change will use the first suitable swap with
the highest configured priority.
Use hibernation configuration as defined in
/sys/power/resume and /sys/power/resume_offset
if present before inspecting /proc/swaps and
attempting to calculate swapfile offset
refactor to use timerfd in place of rtc wakealarm
confirm CLOCK_BOOTTIME_ALARM support in can_s2h
Remove CLOCK_BOOTTIME_ALARM task from TODO
remove unnecessary check on clock_supported return
This reverts commit edda44605f.
The kernel explicitly supports resuming with a different kernel than the one
used before hibernation. If this is something that shouldn't be supported, the
place to change this is in the kernel. We shouldn't censor something that this
exclusively in the kernel's domain.
People might be using this to switch kernels without restaring programs, and
we'd break this functionality for them.
Also, even if resuming with a different kernel was a bad idea, we don't really
prevent that with this check, since most users have more than one kernel and
can freely pick a different one from the menu. So this only affected the corner
case where the kernel has been removed, but there is no reason to single it
out.
Ideally, coccinelle would strip unnecessary braces too. But I do not see any
option in coccinelle for this, so instead, I edited the patch text using
search&replace to remove the braces. Unfortunately this is not fully automatic,
in particular it didn't deal well with if-else-if-else blocks and ifdefs, so
there is an increased likelikehood be some bugs in such spots.
I also removed part of the patch that coccinelle generated for udev, where we
returns -1 for failure. This should be fixed independently.
This reverts 5fdf2d51c2, except for one improved
log message.
Fixes#10613.
Checking if resume= is configured is a good idea, but it turns out we cannot do
it reliably:
- the code only supported boot options with sd-boot, and it's not very widely
used. This means that for most systemd we could only check the current
commandline, not the next one.
- Various systems resume without, e.g. Debian has
/etc/initramfs-tools/conf.d/resume in the initramfs.
Making those checks better would be possible with enough effort, but there'll
be always new systems that boot in a slightly different way and we would need
to keep adding new cases. Longer term, we want to rely on autodetecting the
resume partition, and then checks like this will not be necessary at all. It is
quite clear from the number of bug reports that the number of poeple impacted
by this is quite high now, so let's just drop this.
/etc/systemd/sleep.conf gains four new switches:
AllowSuspend=, AllowHibernation=, AllowSuspendThenHibernate=, AllowHybridSleep=.
Disabling specific modes was already possible by masking suspend.target,
hibernate.target, suspend-then-hibernate.target, or hybrid-sleep.target.
But this is not convenient for distributions, which want to set some defaults
based on what they want to support. Having those available as configuration
makes it easy to put a config file in /usr/lib/systemd/sleep.conf.d/ that
overrides the defaults and gives instructions how to undo that override.
This makes hibernation unavailable if the kernel image we are currently
running was removed. This is supposed to be superficial protection
against hibernating a system we can never return from because the kernel
has been updated and the kernel we currently run is not available
anymore.
We look at a couple of places for the kernel, which should cover all
distributions I know off. Should I have missed a path I am sure people
will quickly notice and we can add more places to check. (or maybe
convince those distros to stick their kernels at a standard place)
On a host with sufficiently large zram but with no actual swap, logind will
respond to CanHibernate() with yes. With this patch, it will correctly respond
no, unless there are other swap devices to consider.
This part of the copyright blurb stems from the GPL use recommendations:
https://www.gnu.org/licenses/gpl-howto.en.html
The concept appears to originate in times where version control was per
file, instead of per tree, and was a way to glue the files together.
Ultimately, we nowadays don't live in that world anymore, and this
information is entirely useless anyway, as people are very welcome to
copy these files into any projects they like, and they shouldn't have to
change bits that are part of our copyright header for that.
hence, let's just get rid of this old cruft, and shorten our codebase a
bit.
Yu Watanabe