Commit 8afbb8e1 authored by Lennart Poettering's avatar Lennart Poettering
Browse files

unit: allow extension of unit files with .d/*.conf drop-ins

For all unit files foobar.service we will now read
foobar.service.d/*.conf, too. This may be used to override certain unit
settings without having to edit unit files directly.

This makes it really easy to change specific settings for services
without having to edit any unit file:

mkdir /etc/systemd/system/avahi-daemon.service.d/
echo -e '[Service]\nNice=99' > /etc/systemd/system/avahi-daemon.service.d/nice.conf
systemctl daemon-reload
parent 5dd9014f
......@@ -81,7 +81,7 @@
sections of the unit files.</para>
<para>In addition to the generic [Unit] and [Install]
sections described here, each unit should have a
sections described here, each unit may have a
type-specific section, e.g. [Service] for a service
unit. See the respective man pages for more
information.</para>
......@@ -106,12 +106,14 @@
<para>Time span values encoded in unit files can be
written in various formats. A stand-alone number
specifies a time in seconds. If suffixed with a time
unit, the unit is honored. A concatenation of
multiple values with units is supported, in which case
the values are added up. Example: "50" refers to 50
unit, the unit is honored. A concatenation of multiple
values with units is supported, in which case the
values are added up. Example: "50" refers to 50
seconds; "2min 200ms" refers to 2 minutes plus 200
milliseconds, i.e. 120200ms. The following time units
are understood: s, min, h, d, w, ms, us. For details see <citerefentry><refentrytitle>systemd.time</refentrytitle><manvolnum>7</manvolnum></citerefentry>.</para>
are understood: s, min, h, d, w, ms, us. For details
see
<citerefentry><refentrytitle>systemd.time</refentrytitle><manvolnum>7</manvolnum></citerefentry>.</para>
<para>Empty lines and lines starting with # or ; are
ignored. This may be used for commenting. Lines ending
......@@ -119,32 +121,42 @@
line while reading and the backslash is replaced by a
space character. This may be used to wrap long lines.</para>
<para>If a line starts with <option>.include</option>
followed by a file name, the specified file will be
parsed at this point. Make sure that the file that is
included has the appropriate section headers before
any directives.</para>
<para>Along with a unit file
<filename>foo.service</filename> a directory
<filename>foo.service</filename> the directory
<filename>foo.service.wants/</filename> may exist. All
units symlinked from such a directory are implicitly
added as dependencies of type
unit files symlinked from such a directory are
implicitly added as dependencies of type
<varname>Wanted=</varname> to the unit. This is useful
to hook units into the start-up of other units,
without having to modify their unit configuration
files. For details about the semantics of
<varname>Wanted=</varname> see below. The preferred
way to create symlinks in the
<filename>.wants/</filename> directory of a service is
with the <command>enable</command> command of the
without having to modify their unit files. For details
about the semantics of <varname>Wanted=</varname> see
below. The preferred way to create symlinks in the
<filename>.wants/</filename> directory of a unit file
is with the <command>enable</command> command of the
<citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>
tool which reads information from the [Install]
section of unit files. (See below.) A similar
section of unit files (see below). A similar
functionality exists for <varname>Requires=</varname>
type dependencies as well, the directory suffix is
<filename>.requires/</filename> in this case.</para>
<para>Along with a unit file
<filename>foo.service</filename> a directory
<filename>foo.service.d/</filename> may exist. All
files with the suffix <filename>.conf</filename> from
this directory will be parsed after the file itself is
parsed. This is useful to alter or add configuration
settings to a unit, without having to modify their
unit files. Make sure that the file that is included
has the appropriate section headers before any
directive.</para>
<para>If a line starts with <option>.include</option>
followed by a file name, the specified file will be
parsed at this point. Make sure that the file that is
included has the appropriate section headers before
any directives.</para>
<para>Note that while systemd offers a flexible
dependency system between units it is recommended to
use this functionality only sparsely and instead rely
......@@ -186,116 +198,7 @@
<para>To refer to the instance string from
within the configuration file you may use the special
<literal>%i</literal> specifier in many of the
configuration options. Other specifiers exist, the
full list is:</para>
<table>
<title>Specifiers available in unit files</title>
<tgroup cols='3' align='left' colsep='1' rowsep='1'>
<colspec colname="spec" />
<colspec colname="mean" />
<colspec colname="detail" />
<thead>
<row>
<entry>Specifier</entry>
<entry>Meaning</entry>
<entry>Details</entry>
</row>
</thead>
<tbody>
<row>
<entry><literal>%n</literal></entry>
<entry>Full unit name</entry>
<entry></entry>
</row>
<row>
<entry><literal>%N</literal></entry>
<entry>Unescaped full unit name</entry>
<entry></entry>
</row>
<row>
<entry><literal>%p</literal></entry>
<entry>Prefix name</entry>
<entry>This refers to the string before the @, i.e. "getty" in the example above, where "tty3" is the instance name.</entry>
</row>
<row>
<entry><literal>%P</literal></entry>
<entry>Unescaped prefix name</entry>
<entry></entry>
</row>
<row>
<entry><literal>%i</literal></entry>
<entry>Instance name</entry>
<entry>This is the string between the @ character and the suffix.</entry>
</row>
<row>
<entry><literal>%I</literal></entry>
<entry>Unescaped instance name</entry>
<entry></entry>
</row>
<row>
<entry><literal>%f</literal></entry>
<entry>Unescaped file name</entry>
<entry>This is either the unescaped instance name (if set) with / prepended (if necessary), or the prefix name similarly prepended with /.</entry>
</row>
<row>
<entry><literal>%c</literal></entry>
<entry>Control group path of the unit</entry>
<entry></entry>
</row>
<row>
<entry><literal>%r</literal></entry>
<entry>Root control group path of systemd</entry>
<entry></entry>
</row>
<row>
<entry><literal>%R</literal></entry>
<entry>Parent directory of the root control group path of systemd</entry>
<entry></entry>
</row>
<row>
<entry><literal>%t</literal></entry>
<entry>Runtime socket dir</entry>
<entry>This is either /run (for the system manager) or $XDG_RUNTIME_DIR (for user managers).</entry>
</row>
<row>
<entry><literal>%u</literal></entry>
<entry>User name</entry>
<entry>This is the name of the configured user of the unit, or (if none is set) the user running the systemd instance.</entry>
</row>
<row>
<entry><literal>%U</literal></entry>
<entry>User uid</entry>
<entry>This is the uid of the configured user of the unit, or (if none is set) the user running the systemd instance.</entry>
</row>
<row>
<entry><literal>%h</literal></entry>
<entry>User home directory</entry>
<entry>This is the home directory of the configured user of the unit, or (if none is set) the user running the systemd instance.</entry>
</row>
<row>
<entry><literal>%s</literal></entry>
<entry>User shell</entry>
<entry>This is the shell of the configured user of the unit, or (if none is set) the user running the systemd instance.</entry>
</row>
<row>
<entry><literal>%m</literal></entry>
<entry>Machine ID</entry>
<entry>The machine ID of the running system, formatted as string. See <citerefentry><refentrytitle>machine-id</refentrytitle><manvolnum>5</manvolnum></citerefentry> for more information.</entry>
</row>
<row>
<entry><literal>%b</literal></entry>
<entry>Boot ID</entry>
<entry>The boot ID of the running system, formatted as string. See <citerefentry><refentrytitle>random</refentrytitle><manvolnum>4</manvolnum></citerefentry> for more information.</entry>
</row>
<row>
<entry><literal>%H</literal></entry>
<entry>Host name</entry>
<entry>The host name of the running system.</entry>
</row>
</tbody>
</tgroup>
</table>
configuration options. See below for details.</para>
<para>If a unit file is empty (i.e. has the file size
0) or is symlinked to <filename>/dev/null</filename>
......@@ -309,6 +212,7 @@
<ulink
url="http://www.freedesktop.org/wiki/Software/systemd/InterfaceStabilityPromise">Interface
Stability Promise</ulink>.</para>
</refsect1>
<refsect1>
......@@ -1084,6 +988,124 @@
</refsect1>
<refsect1>
<title>Specifiers</title>
<para>Many settings resolve specifiers which may be
used to write generic unit files referring to runtime
or unit parameters that are replaced when the unit
files are loaded. The following specifiers are
understood:</para>
<table>
<title>Specifiers available in unit files</title>
<tgroup cols='3' align='left' colsep='1' rowsep='1'>
<colspec colname="spec" />
<colspec colname="mean" />
<colspec colname="detail" />
<thead>
<row>
<entry>Specifier</entry>
<entry>Meaning</entry>
<entry>Details</entry>
</row>
</thead>
<tbody>
<row>
<entry><literal>%n</literal></entry>
<entry>Full unit name</entry>
<entry></entry>
</row>
<row>
<entry><literal>%N</literal></entry>
<entry>Unescaped full unit name</entry>
<entry></entry>
</row>
<row>
<entry><literal>%p</literal></entry>
<entry>Prefix name</entry>
<entry>For instantiated units this refers to the string before the @. For non-instantiated units this refers to to the name of the unit with the type suffix removed.</entry>
</row>
<row>
<entry><literal>%P</literal></entry>
<entry>Unescaped prefix name</entry>
<entry></entry>
</row>
<row>
<entry><literal>%i</literal></entry>
<entry>Instance name</entry>
<entry>For instantiated units: this is the string between the @ character and the suffix.</entry>
</row>
<row>
<entry><literal>%I</literal></entry>
<entry>Unescaped instance name</entry>
<entry></entry>
</row>
<row>
<entry><literal>%f</literal></entry>
<entry>Unescaped file name</entry>
<entry>This is either the unescaped instance name (if applicable) with / prepended (if applicable), or the prefix name similarly prepended with /.</entry>
</row>
<row>
<entry><literal>%c</literal></entry>
<entry>Control group path of the unit</entry>
<entry></entry>
</row>
<row>
<entry><literal>%r</literal></entry>
<entry>Root control group path of systemd</entry>
<entry></entry>
</row>
<row>
<entry><literal>%R</literal></entry>
<entry>Parent directory of the root control group path of systemd</entry>
<entry></entry>
</row>
<row>
<entry><literal>%t</literal></entry>
<entry>Runtime socket dir</entry>
<entry>This is either <filename>/run</filename> (for the system manager) or <literal>$XDG_RUNTIME_DIR</literal> (for user managers).</entry>
</row>
<row>
<entry><literal>%u</literal></entry>
<entry>User name</entry>
<entry>This is the name of the configured user of the unit, or (if none is set) the user running the systemd instance.</entry>
</row>
<row>
<entry><literal>%U</literal></entry>
<entry>User UID</entry>
<entry>This is the UID of the configured user of the unit, or (if none is set) the user running the systemd instance.</entry>
</row>
<row>
<entry><literal>%h</literal></entry>
<entry>User home directory</entry>
<entry>This is the home directory of the configured user of the unit, or (if none is set) the user running the systemd instance.</entry>
</row>
<row>
<entry><literal>%s</literal></entry>
<entry>User shell</entry>
<entry>This is the shell of the configured user of the unit, or (if none is set) the user running the systemd instance.</entry>
</row>
<row>
<entry><literal>%m</literal></entry>
<entry>Machine ID</entry>
<entry>The machine ID of the running system, formatted as string. See <citerefentry><refentrytitle>machine-id</refentrytitle><manvolnum>5</manvolnum></citerefentry> for more information.</entry>
</row>
<row>
<entry><literal>%b</literal></entry>
<entry>Boot ID</entry>
<entry>The boot ID of the running system, formatted as string. See <citerefentry><refentrytitle>random</refentrytitle><manvolnum>4</manvolnum></citerefentry> for more information.</entry>
</row>
<row>
<entry><literal>%H</literal></entry>
<entry>Host name</entry>
<entry>The host name of the running system.</entry>
</row>
</tbody>
</tgroup>
</table>
</refsect1>
<refsect1>
<title>See Also</title>
<para>
......
......@@ -27,10 +27,21 @@
#include "log.h"
#include "strv.h"
#include "unit-name.h"
#include "conf-parser.h"
#include "load-fragment.h"
static int load_dropin_config_file(Unit *u, const char *path) {
assert(u);
assert(path);
if (!endswith(path, ".conf"))
return 0;
return config_parse(path, NULL, UNIT_VTABLE(u)->sections, config_item_perf_lookup, (void*) load_fragment_gperf_lookup, false, u);
}
static int iterate_dir(Unit *u, const char *path, UnitDependency dependency) {
DIR *d;
struct dirent *de;
_cleanup_closedir_ DIR *d = NULL;
int r;
assert(u);
......@@ -38,37 +49,46 @@ static int iterate_dir(Unit *u, const char *path, UnitDependency dependency) {
d = opendir(path);
if (!d) {
if (errno == ENOENT)
return 0;
return -errno;
}
while ((de = readdir(d))) {
char *f;
for (;;) {
struct dirent *de;
union dirent_storage buf;
_cleanup_free_ char *f = NULL;
int k;
k = readdir_r(d, &buf.de, &de);
if (k != 0) {
log_error("Failed to read directory %s: %s", path, strerror(k));
return -k;
}
if (!de)
break;
if (ignore_file(de->d_name))
continue;
f = strjoin(path, "/", de->d_name, NULL);
if (!f) {
r = -ENOMEM;
goto finish;
}
if (!f)
return log_oom();
r = unit_add_dependency_by_name(u, dependency, de->d_name, f, true);
free(f);
if (r < 0)
log_error("Cannot add dependency %s to %s, ignoring: %s", de->d_name, u->id, strerror(-r));
if (dependency >= 0) {
r = unit_add_dependency_by_name(u, dependency, de->d_name, f, true);
if (r < 0)
log_error("Cannot add dependency %s to %s, ignoring: %s", de->d_name, u->id, strerror(-r));
} else {
r = load_dropin_config_file(u, f);
if (r < 0)
log_error("Cannot load drop-in configuration file %s for %s, ignoring: %s", f, u->id, strerror(-r));
}
}
r = 0;
finish:
closedir(d);
return r;
return 0;
}
static int process_dir(Unit *u, const char *unit_path, const char *name, const char *suffix, UnitDependency dependency) {
......@@ -143,6 +163,11 @@ int unit_load_dropin(Unit *u) {
r = process_dir(u, *p, t, ".requires", UNIT_REQUIRES);
if (r < 0)
return r;
/* This loads the drop-in config snippets */
r = process_dir(u, *p, t, ".d", _UNIT_TYPE_INVALID);
if (r < 0)
return r;
}
}
......
......@@ -1781,6 +1781,7 @@ static const char *resolve_template(Unit *u, const char *name, const char*path,
assert(u);
assert(name || path);
assert(p);
if (!name)
name = path_get_file_name(path);
......@@ -1795,7 +1796,8 @@ static const char *resolve_template(Unit *u, const char *name, const char*path,
else {
char *i;
if (!(i = unit_name_to_prefix(u->id)))
i = unit_name_to_prefix(u->id);
if (!i)
return NULL;
s = unit_name_replace_instance(name, i);
......@@ -1812,22 +1814,20 @@ static const char *resolve_template(Unit *u, const char *name, const char*path,
int unit_add_dependency_by_name(Unit *u, UnitDependency d, const char *name, const char *path, bool add_reference) {
Unit *other;
int r;
char *s;
_cleanup_free_ char *s = NULL;
assert(u);
assert(name || path);
if (!(name = resolve_template(u, name, path, &s)))
name = resolve_template(u, name, path, &s);
if (!name)
return -ENOMEM;
if ((r = manager_load_unit(u->manager, name, path, NULL, &other)) < 0)
goto finish;
r = unit_add_dependency(u, d, other, add_reference);
r = manager_load_unit(u->manager, name, path, NULL, &other);
if (r < 0)
return r;
finish:
free(s);
return r;
return unit_add_dependency(u, d, other, add_reference);
}
int unit_add_two_dependencies_by_name(Unit *u, UnitDependency d, UnitDependency e, const char *name, const char *path, bool add_reference) {
......
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