To resolve conflict with sys/mount.h and linux/mount.h or linux/fs.h.
The conflict between sys/mount.h and linux/mount.h is resolved in
glibc-2.37 (774058d72942249f71d74e7f2b639f77184160a6), but our baseline
is still glibc-2.31. Also, even with the version or newer, still
sys/mount.h conflicts with linux/fs.h, which is included by
linux/btrfs.h.
This introduces our own implementation of sys/mount.h, that can be
simultaneously included with linux/mount.h and linux/fs.h. This also
imports linux/fs.h, linux/mount.h, and several other dependent headers.
The introduced sys/mount.h header itself may not be enough simple, but
by using the header, we can drop most of workarounds in other source files.
Nowadays, we define syscall numbers for newer syscalls.
Hence the conditions are not necessary.
This also adds several comments about when syscalls are introduced.
I noticed that systemd-tty-password-agent would time out when asked to
stop via SIGTERM, and eventually be killed, under some circumstances. It
took me a while but i figured out what was going on:
systemd-ask-pw-agent blocks SIGTERM because it wants async notifications
on SIGTERM via signalfd() to listen on. That mostly works great: except
for one case: if we actually get a pw query request, and hence need to
acquire the terminal: we issue open_terminal() in that case, but if the
terminal is used otherwsie we'll hang, and because SIGTERM is blocked
we'll hang and cannot exit cleanly.
Address that: optionally, in open_terminal() look for SIGTERM by
unblcking the signal mask via ppoll() while we wait.
If a non-zero timeout is specified we should not bypass ppoll() even if
no fds are specified, since it will still act as a time based sleep in
that case.
Terminating the plymouth/console agents when the wall agent takes over
can happen asynchronously, after all the pw queries are async anyway and
hence can be seen by both the plymouth/console agents and the wall
agent.
By stopping the two agents with "--no-block" we add a bit of robustness,
since trouble of them exiting won't block the wall agent to start.
This addresses the issue the previous commit fixes in a different way.
I noticed that systemd-tty-password-agent would time out when asked to
stop via SIGTERM, and eventually be killed, under some circumstances.
It took me a while but i figured out what was going on:
systemd-ask-pw-agent blocks SIGTERM because it wants async notifications
on SIGTERM via signalfd() to listen on. That mostly works great: except
for one case: if we actually get a pw query request, and hence need to
acquire the terminal: we issue open_terminal() in that case, but if the
terminal is used otherwsie we'll hang, and because SIGTERM is blocked
we'll hang and cannot exit cleanly.
Address that: optionally, in acquire_terminal() look for SIGTERM by
unblcking the signal mask via ppoll() while we wait.
mkosi switch to the newer -blockdev qemu option in systemd/mkosi#3557 [1], but
cache=unsafe is an option only -drive supports.
Since the qemu-system_x86-64 man page [2] says this, cache.writeback=on is the
default and mkosi setting the other two options to the values corresponding to
unsafe, it should be fine to drop the cache=unsafe option.
┌─────────────┬─────────────────┬──────────────┬────────────────┐
│ │ cache.writeback │ cache.direct │ cache.no-flush │
├─────────────┼─────────────────┼──────────────┼────────────────┤
│writeback │ on │ off │ off │
├─────────────┼─────────────────┼──────────────┼────────────────┤
│none │ on │ on │ off │
├─────────────┼─────────────────┼──────────────┼────────────────┤
│writethrough │ off │ off │ off │
├─────────────┼─────────────────┼──────────────┼────────────────┤
│directsync │ off │ on │ off │
├─────────────┼─────────────────┼──────────────┼────────────────┤
│unsafe │ on │ off │ on │
└─────────────┴─────────────────┴──────────────┴────────────────┘
[1] https://github.com/systemd/mkosi/pull/3557
[2] https://manpages.ubuntu.com/manpages/noble/en/man1/qemu-system-x86_64.1.html
In various scenarios we invoke containers with access to the kernel
keyring blocked. Let's make sure we can handle this properly: when the
invocation ID is stored in in the kernel keyring and we try to read it
and get EPERM we should handle it gracefully, like EOPNOTSUPP.
Yu Watanabe
Lennart Poettering
Mike Yuan
Jörg Behrmann
Steve Ramage