proot provides userspace-powered emulation of chroot and mount --bind,
lending it to be used on environments without unprivileged user
namespaces, or in otherwise restricted environments like Android.
In order to achieve this, proot makes use of the kernel's ptrace()
facility, which we can use in order to detect its presence. Since it
doesn't use any kind of namespacing, including PID namespacing, we don't
need to do any tricks when trying to get the tracer's metadata.
For our purposes, proot is listed as a "container", since we mostly use
this also as the bucket for non-container-but-container-like
technologies like WSL. As such, it seems like a good fit for this
section as well.
There are sometimes users who put unit files in a location that is inaccessible
when systemd starts although they are not found and thus not started because
the corresponding mount units have not activated yet.
There is already a warning for such issue in man 8 systemctl:
link PATH...
...<snip>...
The file system where
the linked unit files are located must be accessible
when systemd is started (e.g. anything underneath /home
or /var is not allowed, unless those directories are
located on the root file system).
However, it looks that it's difficult to find the warning because introductory
users typically doesn't know systemctl link.
Although there is a description in UNIT FILE LOAD PATH pointing to systemctl
link, symlink is now not explicitly mentioned there and thus users doesn't
easily get aware of they should read it.
To deal with this, let's describe "symlink" and "systemctl link" more
explicitly in UNIT FILE LOAD PATH.
When wrong element types are used, directives are sometimes placed in the wrong
section. Also, strip part of text starting with "'", which is used in a few
places and which is displayed improperly in the index.
Discussed in #13743, the -.service semantic conflicts with the
existing root mount and slice names, making this feature not
uniformly extensible to all types. Change the name to be
<type>.d instead.
Updating to this format also extends the top-level dropin to
unit types.
We want users to use Wants, but we'd describe Requires first and ask users to
look for Wants instead. While at it, let's split the wall of text into sensible
paragraphs: syntax first, followed by semantics and longer description, and
finally hints and comparison to other configuration items last.
We slowly added many many conditions over the years, and the text became
very hard to read, because all the terms were squished in one <termitem>.
This rearragnes the text into a new subsection, with minimal grammar changes
and removal of repetitions.
The description of Alias= wasn't incorrect, but it sounded like Alias= creates
a different type of dependency, while it's just a glorified way to create
symlinks. Also recommend 'preset' in addition to 'enable'.
Describe .wants/.requires dirs as equals, without implying that the [Install]
section can only be used for .wants.
The text was partially out of date (systemd-networkd.service now creates as
alias in /etc, not /usr/lib, let's just not say anything about the full path).
Before only one comparison was allowed. Let's make this more flexible:
ConditionKernelVersion = ">=4.0" "<=4.5"
Fixes#12881.
This also fixes expressions like "ConditionKernelVersion=>" which would
evaluate as true.
Originally the description of conditions was brief, so it was acceptable
to put this part at the end. But now we have a myriad conditions, and
this crucial bit of information is easy to miss.
According to the Filesystem Hierarchy Standard, "The /usr/local hierarchy is for use by the system administrator when installing software locally. It needs to be safe from being overwritten when the system software is updated". So it should not be used by installed packages.
The "include" files had type "book" for some raeason. I don't think this
is meaningful. Let's just use the same everywhere.
$ perl -i -0pe 's^..DOCTYPE (book|refentry) PUBLIC "-//OASIS//DTD DocBook XML V4.[25]//EN"\s+"http^<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"\n "http^gms' man/*.xml
No need to waste space, and uniformity is good.
$ perl -i -0pe 's|\n+<!--\s*SPDX-License-Identifier: LGPL-2.1..\s*-->|\n<!-- SPDX-License-Identifier: LGPL-2.1+ -->|gms' man/*.xml
From WordNet (r) 3.0 (2006) [wn]:
time-out
n 1: a brief suspension of play; "each team has two time-outs left"
From The Free On-line Dictionary of Computing (18 March 2015) [foldoc]:
timeout
A period of time after which an error condition is raised if
some event has not occured. A common example is sending a
message. If the receiver does not acknowledge the message
within some preset timeout period, a transmission error is
assumed to have occured.
Lennart Poettering