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authorLennart Poettering <lennart@poettering.net>2014-06-13 19:45:52 +0200
committerLennart Poettering <lennart@poettering.net>2014-06-13 20:11:59 +0200
commit5ae4d543cb9b45ad6c6b82b78da1d6abc2291cdb (patch)
treecf4d8817660f9a2a828c16ce42392703a5ccd690 /man/os-release.xml
parentb0284aba93e8ccd415da5bbee86d84c12b1b9856 (diff)
os-release: define /usr/lib/os-release as fallback for /etc/os-release
The file should have been in /usr/lib/ in the first place, since it describes the OS container in /usr (and not the configuration in /etc), hence, let's support os-release files in /usr/lib as fallback if no version in /etc exists, following the usual override logic. A prior commit already enabled tmpfiles to create /etc/os-release as a symlink to /usr/lib/os-release should it be missing, thus providing nice compatibility with applications only checking in /etc. While it's probably a good idea if all apps check both locations via a fallback logic, it is only necessary in the early boot process, as long as the /etc/os-release symlink has not been restored, in case we boot with an empty /etc.
Diffstat (limited to 'man/os-release.xml')
-rw-r--r--man/os-release.xml38
1 files changed, 29 insertions, 9 deletions
diff --git a/man/os-release.xml b/man/os-release.xml
index c1dd62f715..11443638e5 100644
--- a/man/os-release.xml
+++ b/man/os-release.xml
@@ -49,13 +49,15 @@
<refsynopsisdiv>
<para><filename>/etc/os-release</filename></para>
+ <para><filename>/usr/lib/os-release</filename></para>
</refsynopsisdiv>
<refsect1>
<title>Description</title>
- <para>The <filename>/etc/os-release</filename> file
- contains operating system identification data.</para>
+ <para>The <filename>/etc/os-release</filename> and
+ <filename>/usr/lib/os-release</filename> files contain
+ operating system identification data.</para>
<para>The basic file format of
<filename>os-release</filename> is a newline-separated
@@ -78,20 +80,38 @@
strings. Lines beginning with "#" shall be ignored as
comments.</para>
- <para><filename>/etc/os-release</filename> contains
- data that is defined by the operating system vendor
- and should not be changed by the administrator.</para>
+ <para>The file <filename>/etc/os-release</filename>
+ takes precedence over
+ <filename>/usr/lib/os-release</filename>. Applications
+ should check for the former, and exclusively use its
+ data if it exists, and only fall back to
+ <filename>/usr/lib/os-release</filename> if it is
+ missing. Applications should not read data from both
+ files at the same
+ time. <filename>/usr/lib/os-release</filename> is the
+ recommended place to store OS release information as
+ part of vendor trees. Frequently
+ <filename>/etc/os-release</filename> is simply a
+ symlink to <filename>/usr/lib/os-release</filename>,
+ to provide compatibility with applications only
+ looking at <filename>/etc</filename>.</para>
+
+ <para><filename>os-release</filename> contains data
+ that is defined by the operating system vendor and
+ should generally not be changed by the
+ administrator.</para>
<para>As this file only encodes names and identifiers
it should not be localized.</para>
- <para>The file <filename>/etc/os-release</filename> might
- be a symlink to another file, but it is important that
+ <para>The <filename>/etc/os-release</filename> and
+ <filename>/usr/lib/os-release</filename> files might
+ be symlinks to other files, but it is important that
the file is available from earliest boot on, and hence
must be located on the root file system.</para>
<para>For a longer rationale for
- <filename>/etc/os-release</filename> please refer to
+ <filename>os-release</filename> please refer to
the <ulink
url="http://0pointer.de/blog/projects/os-release">Announcement of <filename>/etc/os-release</filename></ulink>.</para>
</refsect1>
@@ -100,7 +120,7 @@
<title>Options</title>
<para>The following OS identifications parameters may be set using
- <filename>/etc/os-release</filename>:</para>
+ <filename>os-release</filename>:</para>
<variablelist>