We already have the terminal open, hence pass the fd we got to
ask_password_tty(), so that it doesn't have to reopen it a second time.
This is mostly an optimization, but it has the nice benefit of making us
independent from RLIMIT_NOFILE issues and so on, as we don't need to
allocate another fd needlessly.
We should rather sleep to much than too little. This otherwise might
result in a busy loop, because we slept too little and then recheck
again coming to the conclusion we need to go to sleep again, and so on.
We should be careful with these types, and if we do convert between
"int" and "ssize_t" we should do so explicitly rather than implicitly.
Otherwise this just looks like a bug.
Let's forget all relevant terminal features we learnt when we make a
console or /dev/null stdin/stdout/stderr.
Also, while we are at it, let's drop the various _unlikely_ and
_likely_ annotiations around the terminal feature caches. In many cases
we call the relevant functions only once in which cases the annotations
are likely to do just harm and no good. After all we can't know if the
specific code will call us just once or many times...
This modernizes acquire_terminal() in a couple of ways:
1. The three boolean arguments are replaced by a flags parameter, that
should be more descriptive in what it does.
2. We now properly handle inotify queue overruns
3. We use _cleanup_ for closing the fds now, to shorten the code quite a
bit.
Behaviour should not be altered by this.
This adds some paranoia code that moves some of the fds we allocate for
longer periods of times to fds > 2 if they are allocated below this
boundary. This is a paranoid safety thing, in order to avoid that
external code might end up erroneously use our fds under the assumption
they were valid stdin/stdout/stderr. Think: some app closes
stdin/stdout/stderr and then invokes 'fprintf(stderr, …' which causes
writes on our fds.
This both adds the helper to do the moving as well as ports over a
number of users to this new logic. Since we don't want to litter all our
code with invocations of this I tried to strictly focus on fds we keep
open for long periods of times only and only in code that is frequently
loaded into foreign programs (under the assumptions that in our own
codebase we are smart enough to always keep stdin/stdout/stderr
allocated to avoid this pitfall). Specifically this means all code used
by NSS and our sd-xyz API:
1. our logging APIs
2. sd-event
3. sd-bus
4. sd-resolve
5. sd-netlink
This changed was inspired by this:
https://github.com/systemd/systemd/issues/8075#issuecomment-363689755
This shows that apparently IRL there are programs that do close
stdin/stdout/stderr, and we should accomodate for that.
Note that this won't fix any bugs, this just makes sure that buggy
programs are less likely to interfere with out own code.
This change adds support for controlling the suspend-on-lid-close
behaviour based on the power status as well as whether the machine is
docked or has an external monitor. For backwards compatibility the new
configuration file variable is ignored completely by default, and must
be set explicitly before being considered in any decisions.
Let's read the PID file after all if there's a potentially unsafe
symlink chain in place. But if we do, then refuse taking the PID if its
outside of the cgroup.
Fixes: #8085
So far we didn't document control, transient, dbus config, or generator paths.
But those paths are visible to users, and they need to understand why systemd
loads units from those paths, and how the precedence hierarchy looks.
The whole thing is a bit messy, since the list of paths is quite long.
I made the tables a bit shorter by combining rows for the alternatives
where $XDG_* is set and the fallback.
In various places, tags are split like <element
param="blah">
this. This is necessary to keep everyting in one logical XML line so that
docbook renders the table properly.
Replaces #8050.
$ diff -u <(old/systemd-analyze --user unit-paths) <(new/systemd-analyze --user unit-paths)|colordiff
--- /proc/self/fd/14 2018-02-08 14:36:34.190046129 +0100
+++ /proc/self/fd/15 2018-02-08 14:36:34.190046129 +0100
@@ -1,5 +1,5 @@
-/home/zbyszek/.config/systemd/system.control
-/run/user/1000/systemd/system.control
+/home/zbyszek/.config/systemd/user.control
+/run/user/1000/systemd/user.control
/run/user/1000/systemd/transient
...
Strictly speaking, online upgrades of user instances through daemon-reexec will
be broken. We can get away with this since
a) reexecs of the user instance are not commonly done, at least package upgrade
scripts don't do this afawk.
b) cgroups aren't delegateable on cgroupsv1 there's little reason to use "systemctl
set-property" for --user mode
It's not good if the paths are in different order. With --user, we expect
more paths, but it must be a strict superset, and the order for the ones
that appear in both sets must be the same.
$ diff -u <(build/systemd-analyze --global unit-paths) <(build/systemd-analyze --user unit-paths)|colordiff
--- /proc/self/fd/14 2018-02-08 14:11:45.425353107 +0100
+++ /proc/self/fd/15 2018-02-08 14:11:45.426353116 +0100
@@ -1,6 +1,17 @@
+/home/zbyszek/.config/systemd/system.control
+/run/user/1000/systemd/system.control
+/run/user/1000/systemd/transient
+/run/user/1000/systemd/generator.early
+/home/zbyszek/.config/systemd/user
/etc/systemd/user
+/run/user/1000/systemd/user
/run/systemd/user
+/run/user/1000/systemd/generator
+/home/zbyszek/.local/share/systemd/user
+/home/zbyszek/.local/share/flatpak/exports/share/systemd/user
+/var/lib/flatpak/exports/share/systemd/user
/usr/local/share/systemd/user
/usr/share/systemd/user
/usr/local/lib/systemd/user
/usr/lib/systemd/user
+/run/user/1000/systemd/generator.late
A test is added so that we don't regress on this.
This doesn't matter that much, because set-property --global does not work,
so at least those paths wouldn't be used automatically. It is still possible
to create such snippets manually, so we better fix this.
There are cases that we want to trigger and settle only specific
commands. For example, let's say at boot time we want to make sure all
the graphics devices are working correctly because it's critical for
booting, but not the USB subsystem (we'll trigger USB events later). So
we do:
udevadm trigger --action="add" --subsystem-match="graphics"
udevadm settle
However, we cannot block the kernel from emitting kernel events from
discovering USB devices. So if any of the USB kernel event was emitted
before the settle command, the settle command would still wait for the
entire queue to complete. And if the USB event takes a long time to be
processed, the system slows down.
The new `settle` option allows the `trigger` command to wait for only
the triggered events, and effectively solves this problem.
CAP_ADMIN does not exist (the closest existing capability name would be
CAP_SYS_ADMIN), and according to man:open(2) and man:capabilities(7),
the capability required to specify O_NOATIME is actually CAP_FOWNER.
Lennart Poettering