shaba/systemd
1
0
Fork 0
mirror of https://github.com/systemd/systemd.git synced 2024-12-22 17:35:35 +03:00
Code

Merge pull request #17859 from keszybz/hostnamed-export-hostname-origin-and-simplify-logic

Browse Source 
Export hostname origin and simplify logic in hostamed
This commit is contained in:
Yu Watanabe 2020-12-17 00:55:49 +09:00 committed by GitHub
commit ecfbbf098c
No known key found for this signature in database
GPG Key ID: 4AEE18F83AFDEB23
27 changed files with 594 additions and 429 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

77
man/hostname.xml
View File

@ -1,6 +1,9 @@
<?xml version='1.0'?> <!--*-nxml-*--> <?xml version='1.0'?> <!--*-nxml-*-->
<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN" <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd"> "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd" [
<!ENTITY % entities SYSTEM "custom-entities.ent" >
%entities;
]>
<!-- SPDX-License-Identifier: LGPL-2.1-or-later --> <!-- SPDX-License-Identifier: LGPL-2.1-or-later -->
<refentry id="hostname"> <refentry id="hostname">
@ -26,23 +29,65 @@
<refsect1> <refsect1>
<title>Description</title> <title>Description</title>
<para>The <filename>/etc/hostname</filename> file configures the <para>The <filename>/etc/hostname</filename> file configures the name of the local system. Unless
name of the local system that is set during boot using the overridden as described in the next section,
<citerefentry><refentrytitle>sethostname</refentrytitle><manvolnum>2</manvolnum></citerefentry> <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry> will set this
system call. It should contain a single newline-terminated hostname during boot using the
hostname string. Comments (lines starting with a `#') are ignored. <citerefentry><refentrytitle>sethostname</refentrytitle><manvolnum>2</manvolnum></citerefentry> system
The hostname may be a free-form string up to 64 characters in length; call.</para>
however, it is recommended that it consists only of 7-bit ASCII lower-case
characters and no spaces or dots, and limits itself to the format allowed <para>The file should contain a single newline-terminated hostname string. Comments (lines starting with
for DNS domain name labels, even though this is not a strict a <literal>#</literal>) are ignored. The hostname should be composed of up to 64 7-bit ASCII lower-case
requirement.</para> alphanumeric characters or hyphens forming a valid DNS domain name. It is recommended that this name
contains only a single label, i.e. without any dots. Invalid characters will be filtered out in an
attempt to make the name valid, but obviously it is recommended to use a valid name and not rely on this
filtering.</para>
<para>You may use <para>You may use
<citerefentry><refentrytitle>hostnamectl</refentrytitle><manvolnum>1</manvolnum></citerefentry> <citerefentry><refentrytitle>hostnamectl</refentrytitle><manvolnum>1</manvolnum></citerefentry> to change
to change the value of this file during runtime from the command the value of this file during runtime from the command line. Use
line. Use <citerefentry><refentrytitle>systemd-firstboot</refentrytitle><manvolnum>1</manvolnum></citerefentry> to
<citerefentry><refentrytitle>systemd-firstboot</refentrytitle><manvolnum>1</manvolnum></citerefentry> initialize it on mounted (but not booted) system images.</para>
to initialize it on mounted (but not booted) system images.</para> </refsect1>
<refsect1>
<title>Hostname semantics</title>
<para><citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry> and the
associated tools will obtain the hostname in the following ways:</para>
<itemizedlist>
<listitem><para>If the kernel commandline parameter <varname>systemd.hostname=</varname> specifies a
valid hostname,
<citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry> will use it
to set the hostname during early boot, see
<citerefentry><refentrytitle>kernel-command-line</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
</para></listitem>
<listitem><para>Otherwise, the "static" hostname specified by <filename>/etc/hostname</filename> as
described above will be used.</para></listitem>
<listitem><para>Otherwise, a transient hostname may be set during runtime, for example based on
information in a DHCP lease, see
<citerefentry><refentrytitle>systemd-hostnamed.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
Both <ulink url="https://developer.gnome.org/NetworkManager/stable/">NetworkManager</ulink> and
<citerefentry><refentrytitle>systemd-networkd.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>
allow this. Note that
<citerefentry><refentrytitle>systemd-hostnamed.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>
gives higher priority to the static hostname, so the transient hostname will only be used if the static
hostname is not configured.</para></listitem>
<listitem><para>Otherwise, a fallback hostname configured at compilation time will be used
(<literal>&FALLBACK_HOSTNAME;</literal>).</para></listitem>
<!-- what about the "linux" fallback fallback? -->
</itemizedlist>
<para>Effectively, the static hostname has higher priority than a transient hostname, which has higher
priority than the fallback hostname. Transient hostnames are equivalent, so setting a new transient
hostname causes the previous transient hostname to be forgotten. The hostname specified on the kernel
command line is like a transient hostname, with the exception that it has higher priority when the
machine boots. Also note that those are the semantics implemented by systemd tools, but other programs
may also set the hostname.</para>
</refsect1> </refsect1>
<refsect1> <refsect1>

30
man/hostnamectl.xml
View File

@ -32,33 +32,23 @@
<refsect1> <refsect1>
<title>Description</title> <title>Description</title>
<para><command>hostnamectl</command> may be used to query and <para><command>hostnamectl</command> may be used to query and change the system hostname and related
change the system hostname and related settings.</para> settings.</para>
<para>This tool distinguishes three different hostnames: the <para><citerefentry><refentrytitle>systemd-hostnamed.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>
high-level "pretty" hostname which might include all kinds of and this tool distinguish three different hostnames: the high-level "pretty" hostname which might include
special characters (e.g. "Lennart's Laptop"), the static hostname all kinds of special characters (e.g. "Lennart's Laptop"), the "static" hostname which is the
which is used to initialize the kernel hostname at boot (e.g. user-configured hostname (e.g. "lennarts-laptop"), and the transient hostname which is a fallback value
"lennarts-laptop"), and the transient hostname which is a fallback received from network configuration (e.g. "node12345678"). If a static hostname is set to a valid value,
value received from network configuration. If a static hostname is then the transient hostname is not used.</para>
set, and is valid (something other than localhost), then the
transient hostname is not used.</para>
<para>Note that the pretty hostname has little restrictions on the characters and length used, while the static and <para>Note that the pretty hostname has little restrictions on the characters and length used, while the static and
transient hostnames are limited to the usually accepted characters of Internet domain names, and 64 characters at transient hostnames are limited to the usually accepted characters of Internet domain names, and 64 characters at
maximum (the latter being a Linux limitation).</para> maximum (the latter being a Linux limitation).</para>
<para>The static hostname is stored in
<filename>/etc/hostname</filename>, see
<citerefentry><refentrytitle>hostname</refentrytitle><manvolnum>5</manvolnum></citerefentry>
for more information. The pretty hostname, chassis type, and icon
name are stored in <filename>/etc/machine-info</filename>, see
<citerefentry><refentrytitle>machine-info</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para>
<para>Use <para>Use
<citerefentry><refentrytitle>systemd-firstboot</refentrytitle><manvolnum>1</manvolnum></citerefentry> <citerefentry><refentrytitle>systemd-firstboot</refentrytitle><manvolnum>1</manvolnum></citerefentry> to
to initialize the system hostname for mounted (but not booted) initialize the system hostname for mounted (but not booted) system images.</para>
system images.</para>
</refsect1> </refsect1>
<refsect1> <refsect1>

105
man/org.freedesktop.hostname1.xml
View File

@ -62,6 +62,9 @@ node /org/freedesktop/hostname1 {
readonly s Hostname = '...'; readonly s Hostname = '...';
readonly s StaticHostname = '...'; readonly s StaticHostname = '...';
readonly s PrettyHostname = '...'; readonly s PrettyHostname = '...';
@org.freedesktop.DBus.Property.EmitsChangedSignal("const")
readonly s FallbackHostname = '...';
readonly s HostnameSource = '...';
readonly s IconName = '...'; readonly s IconName = '...';
readonly s Chassis = '...'; readonly s Chassis = '...';
readonly s Deployment = '...'; readonly s Deployment = '...';
@ -113,6 +116,10 @@ node /org/freedesktop/hostname1 {
<variablelist class="dbus-property" generated="True" extra-ref="PrettyHostname"/> <variablelist class="dbus-property" generated="True" extra-ref="PrettyHostname"/>
<variablelist class="dbus-property" generated="True" extra-ref="FallbackHostname"/>
<variablelist class="dbus-property" generated="True" extra-ref="HostnameSource"/>
<variablelist class="dbus-property" generated="True" extra-ref="IconName"/> <variablelist class="dbus-property" generated="True" extra-ref="IconName"/>
<variablelist class="dbus-property" generated="True" extra-ref="Chassis"/> <variablelist class="dbus-property" generated="True" extra-ref="Chassis"/>
@ -144,55 +151,61 @@ node /org/freedesktop/hostname1 {
<refsect1> <refsect1>
<title>Semantics</title> <title>Semantics</title>
<para>The <emphasis>static (configured) hostname</emphasis> is the one configured in <para>The <varname>StaticHostname</varname> property exposes the "static" hostname configured in
<filename>/etc/hostname</filename>. It is chosen by the local user. It is not always in sync with the <filename>/etc/hostname</filename>. It is not always in sync with the current hostname as returned by the
current hostname as returned by the
<citerefentry project="man-pages"><refentrytitle>gethostname</refentrytitle><manvolnum>3</manvolnum></citerefentry> <citerefentry project="man-pages"><refentrytitle>gethostname</refentrytitle><manvolnum>3</manvolnum></citerefentry>
system call. If no hostname is configured this property will be the empty string. Setting this property system call. If no static hostname is configured this property will be the empty string.</para>
to the empty string will remove <filename>/etc/hostname</filename>. This property should be an
internet-style hostname, 7-bit lowercase ASCII, no special chars/spaces.</para>
<para>The <emphasis>transient (dynamic) hostname</emphasis> is the one configured via the kernel's <para>When <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry> or
<citerefentry><refentrytitle>systemd-hostnamed.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>
set the hostname, this static hostname <emphasis>has the highest priority</emphasis>.</para>
<para>The <varname>Hostname</varname> property exposes the actual hostname configured in the kernel via
<citerefentry project="man-pages"><refentrytitle>sethostname</refentrytitle><manvolnum>3</manvolnum></citerefentry>. <citerefentry project="man-pages"><refentrytitle>sethostname</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
It can be different from the static hostname if DHCP or mDNS have been configured to change the name It can be different from the static hostname. This property is never empty.</para>
based on network information. <!-- FIXME: it's not DHCP that configures this... -->
This property is never empty. If no hostname is set this will default to
<literal>&FALLBACK_HOSTNAME;</literal> (configurable at compilation time). Setting this property to the
empty string will reset the dynamic hostname to the static hostname. If no static hostname is
configured the dynamic hostname will be reset to <literal>&FALLBACK_HOSTNAME;</literal>. This property
should be an internet-style hostname, 7-bit lowercase ASCII, no special chars/spaces.</para>
<para>The <emphasis>pretty hostname</emphasis> is a free-form UTF-8 hostname for presentation to the <para>The <varname>PrettyHostname</varname> property exposes the <emphasis>pretty hostname</emphasis>
user. User interfaces should ensure that the pretty hostname and the static hostname stay in sync. which is a free-form UTF-8 hostname for presentation to the user. User interfaces should ensure that the
I.e. when the former is <literal>Lennart’s Computer</literal> the latter should be pretty hostname and the static hostname stay in sync. E.g. when the former is <literal>Lennart’s
<literal>lennarts-computer</literal>. If no pretty hostname is set this setting will be the empty Computer</literal> the latter should be <literal>lennarts-computer</literal>. If no pretty hostname is
string. Applications should then find a suitable fallback, such as the dynamic hostname.</para> set this setting will be the empty string. Applications should then find a suitable fallback, such as the
dynamic hostname.</para>
<para>The <emphasis>icon name</emphasis> is a name following the XDG icon naming spec. If not set, <para>The <varname>FallbackHostname</varname> property exposes the fallback hostname (configured at
information such as the chassis type (see below) is used to find a suitable fallback icon name compilation time).</para>
(i.e. <literal>computer-laptop</literal> vs. <literal>computer-desktop</literal> is picked based on the
chassis information). If no such data is available, the empty string is returned. In that case an application
should fall back to a replacement icon, for example <literal>computer</literal>. If this property is set
to the empty string, the automatic fallback name selection is enabled again.</para>
<para>The <emphasis>chassis type</emphasis> should be one of the currently defined chassis types: <para>The <varname>HostnameSource</varname> property exposes the origin of the currently configured
<literal>desktop</literal>, <literal>laptop</literal>, <literal>server</literal>, hostname. One of <literal>static</literal> (set from <filename>/etc/hostname</filename>),
<literal>tablet</literal>, <literal>handset</literal>, as well as the special chassis types <literal>transient</literal> (a non-permanent hostname from an external source),
<literal>vm</literal> and <literal>container</literal> for virtualized systems. Note that in most cases <literal>fallback</literal> (the compiled-in fallback value).</para>
the chassis type will be determined automatically from DMI/SMBIOS/ACPI firmware information. Writing to
this setting is hence useful only to override misdetected chassis types, or to configure the chassis type if <para>The <varname>IconName</varname> property exposes the <emphasis>icon name</emphasis> following the
it could not be auto-detected. Set this property to the empty string to reenable the automatic detection of XDG icon naming spec. If not set, information such as the chassis type (see below) is used to find a
the chassis type from firmware information.</para> suitable fallback icon name (i.e. <literal>computer-laptop</literal>
vs. <literal>computer-desktop</literal> is picked based on the chassis information). If no such data is
available, the empty string is returned. In that case an application should fall back to a replacement
icon, for example <literal>computer</literal>. If this property is set to the empty string, the automatic
fallback name selection is enabled again.</para>
<para>The <varname>Chassis</varname> property exposes a <emphasis>chassis type</emphasis>, one of the
currently defined chassis types: <literal>desktop</literal>, <literal>laptop</literal>,
<literal>server</literal>, <literal>tablet</literal>, <literal>handset</literal>, as well as the special
chassis types <literal>vm</literal> and <literal>container</literal> for virtualized systems. Note that
in most cases the chassis type will be determined automatically from DMI/SMBIOS/ACPI firmware
information. Writing to this setting is hence useful only to override misdetected chassis types, or to
configure the chassis type if it could not be auto-detected. Set this property to the empty string to
reenable the automatic detection of the chassis type from firmware information.</para>
<para>Note that <filename>systemd-hostnamed</filename> starts only on request and terminates after a <para>Note that <filename>systemd-hostnamed</filename> starts only on request and terminates after a
short idle period. This effectively means that <function>PropertyChanged</function> messages are not sent short idle period. This effectively means that <function>PropertyChanged</function> messages are not sent
out for changes made directly on the files (as in: administrator edits the files with vi). This is out for changes made directly on the files (as in: administrator edits the files with vi). This is
the intended behavior: manual configuration changes should require manual reloading.</para> the intended behavior: manual configuration changes should require manual reloading.</para>
<para>The transient (dynamic) hostname maps directly to the kernel hostname. This hostname should be <para>The transient (dynamic) hostname exposed by the <varname>Hostname</varname> property maps directly
assumed to be highly dynamic, and hence should be watched directly, without depending on to the kernel hostname. This hostname should be assumed to be highly dynamic, and hence should be watched
<function>PropertyChanged</function> messages from <filename>systemd-hostnamed</filename>. To accomplish directly, without depending on <function>PropertyChanged</function> messages from
this, open <filename>/proc/sys/kernel/hostname</filename> and <filename>systemd-hostnamed</filename>. To accomplish this, open
<filename>/proc/sys/kernel/hostname</filename> and
<citerefentry project="man-pages"><refentrytitle>poll</refentrytitle><manvolnum>3</manvolnum></citerefentry> <citerefentry project="man-pages"><refentrytitle>poll</refentrytitle><manvolnum>3</manvolnum></citerefentry>
for <constant>SIGHUP</constant> which is triggered by the kernel every time the hostname changes. Again: for <constant>SIGHUP</constant> which is triggered by the kernel every time the hostname changes. Again:
this is special for the transient (dynamic) hostname, and does not apply to the configured (fixed) this is special for the transient (dynamic) hostname, and does not apply to the configured (fixed)
@ -206,15 +219,17 @@ node /org/freedesktop/hostname1 {
for that. For more information on these files and syscalls see the respective man pages.</para> for that. For more information on these files and syscalls see the respective man pages.</para>
<refsect2> <refsect2>
<title>Methods and Properties</title> <title>Methods</title>
<para><function>SetHostname()</function> sets the transient (dynamic) hostname which is exposed by the <para><function>SetHostname()</function> sets the transient (dynamic) hostname, which is used if no
<varname>Hostname</varname> property. If empty, the transient hostname is set to the static hostname. static hostname is set. This value must be an internet-style hostname, 7-bit lowercase ASCII, no
</para> special chars/spaces. An empty string will unset the transient hostname.</para>
<para><function>SetStaticHostname()</function> sets the static hostname which is exposed by the <para><function>SetStaticHostname()</function> sets the static hostname which is exposed by the
<varname>StaticHostname</varname> property. If empty, the built-in default of <varname>StaticHostname</varname> property. When called with an empty argument, the static
<literal>&FALLBACK_HOSTNAME;</literal> is used.</para> configuration in <filename>/etc/hostname</filename> is removed. Since the static hostname has the
highest priority, calling this function usually affects also the <varname>Hostname</varname> property
and the effective hostname configured in the kernel.</para>
<para><function>SetPrettyHostname()</function> sets the pretty hostname which is exposed by the <para><function>SetPrettyHostname()</function> sets the pretty hostname which is exposed by the
<varname>PrettyHostname</varname> property.</para> <varname>PrettyHostname</varname> property.</para>
@ -287,10 +302,6 @@ node /org/freedesktop/hostname1 {
with <citerefentry><refentrytitle>nss-myhostname</refentrytitle><manvolnum>3</manvolnum></citerefentry>. with <citerefentry><refentrytitle>nss-myhostname</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
</para> </para>
<para>A client that wants to change the local hostname for DHCP/mDNS should invoke
<code>SetHostname("newname", false)</code> as soon as the name is available and afterwards reset it via
<code>SetHostname("")</code>.</para>
<para>Here are some recommendations to follow when generating a static (internet) hostname from a pretty <para>Here are some recommendations to follow when generating a static (internet) hostname from a pretty
name: name:
<itemizedlist> <itemizedlist>

10
man/systemd-hostnamed.service.xml
View File

@ -51,9 +51,15 @@
</listitem> </listitem>
</itemizedlist></para> </itemizedlist></para>
<para>The static hostname is stored in <filename>/etc/hostname</filename>, see
<citerefentry><refentrytitle>hostname</refentrytitle><manvolnum>5</manvolnum></citerefentry> for more
information. The pretty hostname, chassis type, and icon name are stored in
<filename>/etc/machine-info</filename>, see
<citerefentry><refentrytitle>machine-info</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para>
<para>The tool <para>The tool
<citerefentry><refentrytitle>hostnamectl</refentrytitle><manvolnum>1</manvolnum></citerefentry> <citerefentry><refentrytitle>hostnamectl</refentrytitle><manvolnum>1</manvolnum></citerefentry> is a
is a command line client to this service.</para> command line client to this service.</para>
<para>See <para>See
<citerefentry><refentrytitle>org.freedesktop.hostname1</refentrytitle><manvolnum>5</manvolnum></citerefentry> <citerefentry><refentrytitle>org.freedesktop.hostname1</refentrytitle><manvolnum>5</manvolnum></citerefentry>

120
src/basic/hostname-util.c
View File

@ -7,28 +7,10 @@
#include <unistd.h> #include <unistd.h>
#include "alloc-util.h" #include "alloc-util.h"
#include "fd-util.h"
#include "fileio.h"
#include "hostname-util.h" #include "hostname-util.h"
#include "macro.h"
#include "string-util.h" #include "string-util.h"
#include "strv.h" #include "strv.h"
bool hostname_is_set(void) {
struct utsname u;
assert_se(uname(&u) >= 0);
if (isempty(u.nodename))
return false;
/* This is the built-in kernel default hostname */
if (streq(u.nodename, "(none)"))
return false;
return true;
}
char* gethostname_malloc(void) { char* gethostname_malloc(void) {
struct utsname u; struct utsname u;
const char *s; const char *s;
@ -208,105 +190,3 @@ bool is_localhost(const char *hostname) {
endswith_no_case(hostname, ".localhost.localdomain") || endswith_no_case(hostname, ".localhost.localdomain") ||
endswith_no_case(hostname, ".localhost.localdomain."); endswith_no_case(hostname, ".localhost.localdomain.");
} }
int sethostname_idempotent(const char *s) {
char buf[HOST_NAME_MAX + 1] = {};
assert(s);
if (gethostname(buf, sizeof(buf)) < 0)
return -errno;
if (streq(buf, s))
return 0;
if (sethostname(s, strlen(s)) < 0)
return -errno;
return 1;
}
int shorten_overlong(const char *s, char **ret) {
char *h, *p;
/* Shorten an overlong name to HOST_NAME_MAX or to the first dot,
* whatever comes earlier. */
assert(s);
h = strdup(s);
if (!h)
return -ENOMEM;
if (hostname_is_valid(h, 0)) {
*ret = h;
return 0;
}
p = strchr(h, '.');
if (p)
*p = 0;
strshorten(h, HOST_NAME_MAX);
if (!hostname_is_valid(h, 0)) {
free(h);
return -EDOM;
}
*ret = h;
return 1;
}
int read_etc_hostname_stream(FILE *f, char **ret) {
int r;
assert(f);
assert(ret);
for (;;) {
_cleanup_free_ char *line = NULL;
char *p;
r = read_line(f, LONG_LINE_MAX, &line);
if (r < 0)
return r;
if (r == 0) /* EOF without any hostname? the file is empty, let's treat that exactly like no file at all: ENOENT */
return -ENOENT;
p = strstrip(line);
/* File may have empty lines or comments, ignore them */
if (!IN_SET(*p, '\0', '#')) {
char *copy;
hostname_cleanup(p); /* normalize the hostname */
if (!hostname_is_valid(p, VALID_HOSTNAME_TRAILING_DOT)) /* check that the hostname we return is valid */
return -EBADMSG;
copy = strdup(p);
if (!copy)
return -ENOMEM;
*ret = copy;
return 0;
}
}
}
int read_etc_hostname(const char *path, char **ret) {
_cleanup_fclose_ FILE *f = NULL;
assert(ret);
if (!path)
path = "/etc/hostname";
f = fopen(path, "re");
if (!f)
return -errno;
return read_etc_hostname_stream(f, ret);
}

9
src/basic/hostname-util.h
View File

@ -7,8 +7,6 @@
#include "macro.h" #include "macro.h"
#include "strv.h" #include "strv.h"
bool hostname_is_set(void);
char* gethostname_malloc(void); char* gethostname_malloc(void);
char* gethostname_short_malloc(void); char* gethostname_short_malloc(void);
int gethostname_strict(char **ret); int gethostname_strict(char **ret);
@ -29,10 +27,3 @@ static inline bool is_gateway_hostname(const char *hostname) {
/* This tries to identify the valid syntaxes for the our synthetic "gateway" host. */ /* This tries to identify the valid syntaxes for the our synthetic "gateway" host. */
return STRCASE_IN_SET(hostname, "_gateway", "_gateway."); return STRCASE_IN_SET(hostname, "_gateway", "_gateway.");
} }
int sethostname_idempotent(const char *s);
int shorten_overlong(const char *s, char **ret);
int read_etc_hostname_stream(FILE *f, char **ret);
int read_etc_hostname(const char *path, char **ret);

1
src/basic/string-table.h
View File

@ -78,6 +78,7 @@ ssize_t string_table_lookup(const char * const *table, size_t len, const char *k
_DEFINE_STRING_TABLE_LOOKUP_FROM_STRING_WITH_BOOLEAN(name,type,yes,scope) _DEFINE_STRING_TABLE_LOOKUP_FROM_STRING_WITH_BOOLEAN(name,type,yes,scope)
#define DEFINE_STRING_TABLE_LOOKUP(name,type) _DEFINE_STRING_TABLE_LOOKUP(name,type,) #define DEFINE_STRING_TABLE_LOOKUP(name,type) _DEFINE_STRING_TABLE_LOOKUP(name,type,)
#define DEFINE_STRING_TABLE_LOOKUP_TO_STRING(name,type) _DEFINE_STRING_TABLE_LOOKUP_TO_STRING(name,type,)
#define DEFINE_PRIVATE_STRING_TABLE_LOOKUP(name,type) _DEFINE_STRING_TABLE_LOOKUP(name,type,static) #define DEFINE_PRIVATE_STRING_TABLE_LOOKUP(name,type) _DEFINE_STRING_TABLE_LOOKUP(name,type,static)
#define DEFINE_PRIVATE_STRING_TABLE_LOOKUP_TO_STRING(name,type) _DEFINE_STRING_TABLE_LOOKUP_TO_STRING(name,type,static) #define DEFINE_PRIVATE_STRING_TABLE_LOOKUP_TO_STRING(name,type) _DEFINE_STRING_TABLE_LOOKUP_TO_STRING(name,type,static)
#define DEFINE_PRIVATE_STRING_TABLE_LOOKUP_FROM_STRING(name,type) _DEFINE_STRING_TABLE_LOOKUP_FROM_STRING(name,type,static) #define DEFINE_PRIVATE_STRING_TABLE_LOOKUP_FROM_STRING(name,type) _DEFINE_STRING_TABLE_LOOKUP_FROM_STRING(name,type,static)

62
src/core/hostname-setup.c
View File

@ -1,62 +0,0 @@
/* SPDX-License-Identifier: LGPL-2.1-or-later */
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include "alloc-util.h"
#include "fileio.h"
#include "hostname-setup.h"
#include "hostname-util.h"
#include "log.h"
#include "macro.h"
#include "proc-cmdline.h"
#include "string-util.h"
#include "util.h"
int hostname_setup(void) {
_cleanup_free_ char *b = NULL;
const char *hn = NULL;
bool enoent = false;
int r;
r = proc_cmdline_get_key("systemd.hostname", 0, &b);
if (r < 0)
log_warning_errno(r, "Failed to retrieve system hostname from kernel command line, ignoring: %m");
else if (r > 0) {
if (hostname_is_valid(b, VALID_HOSTNAME_TRAILING_DOT))
hn = b;
else {
log_warning("Hostname specified on kernel command line is invalid, ignoring: %s", b);
b = mfree(b);
}
}
if (!hn) {
r = read_etc_hostname(NULL, &b);
if (r == -ENOENT)
enoent = true;
else if (r < 0)
log_warning_errno(r, "Failed to read configured hostname, ignoring: %m");
else
hn = b;
}
if (isempty(hn)) {
/* Don't override the hostname if it is already set and not explicitly configured */
if (hostname_is_set())
return 0;
if (enoent)
log_info("No hostname configured.");
hn = FALLBACK_HOSTNAME;
}
r = sethostname_idempotent(hn);
if (r < 0)
return log_warning_errno(r, "Failed to set hostname to <%s>: %m", hn);
log_info("Set hostname to <%s>.", hn);
return 0;
}

4
src/core/hostname-setup.h
View File

@ -1,4 +0,0 @@
/* SPDX-License-Identifier: LGPL-2.1-or-later */
#pragma once
int hostname_setup(void);

2
src/core/main.c
View File

@ -2064,7 +2064,7 @@ static int initialize_runtime(
} }
status_welcome(); status_welcome();
hostname_setup(); (void) hostname_setup(true);
/* Force transient machine-id on first boot. */ /* Force transient machine-id on first boot. */
machine_id_setup(NULL, first_boot, arg_machine_id, NULL); machine_id_setup(NULL, first_boot, arg_machine_id, NULL);
(void) loopback_setup(); (void) loopback_setup();

2
src/core/meson.build
View File

@ -76,8 +76,6 @@ libcore_sources = '''
execute.h execute.h
generator-setup.c generator-setup.c
generator-setup.h generator-setup.h
hostname-setup.c
hostname-setup.h
ima-setup.c ima-setup.c
ima-setup.h ima-setup.h
ip-address-access.c ip-address-access.c

2
src/fuzz/fuzz-hostname-util.c → src/fuzz/fuzz-hostname-setup.c
View File

@ -4,7 +4,7 @@
#include "fd-util.h" #include "fd-util.h"
#include "fileio.h" #include "fileio.h"
#include "fuzz.h" #include "fuzz.h"
#include "hostname-util.h" #include "hostname-setup.h"
int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) { int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
_cleanup_fclose_ FILE *f = NULL; _cleanup_fclose_ FILE *f = NULL;

2
src/fuzz/meson.build
View File

@ -123,7 +123,7 @@ fuzzers += [
[libshared], [libshared],
[]], []],
[['src/fuzz/fuzz-hostname-util.c'], [['src/fuzz/fuzz-hostname-setup.c'],
[libshared], [libshared],
[]], []],

169
src/hostname/hostnamed.c
View File

@ -8,6 +8,7 @@
#include "alloc-util.h" #include "alloc-util.h"
#include "bus-common-errors.h" #include "bus-common-errors.h"
#include "bus-get-properties.h"
#include "bus-log-control-api.h" #include "bus-log-control-api.h"
#include "bus-polkit.h" #include "bus-polkit.h"
#include "def.h" #include "def.h"
@ -16,6 +17,7 @@
#include "env-util.h" #include "env-util.h"
#include "fileio-label.h" #include "fileio-label.h"
#include "fileio.h" #include "fileio.h"
#include "hostname-setup.h"
#include "hostname-util.h" #include "hostname-util.h"
#include "id128-util.h" #include "id128-util.h"
#include "main-func.h" #include "main-func.h"
@ -29,6 +31,7 @@
#include "service-util.h" #include "service-util.h"
#include "signal-util.h" #include "signal-util.h"
#include "stat-util.h" #include "stat-util.h"
#include "string-table.h"
#include "strv.h" #include "strv.h"
#include "user-util.h" #include "user-util.h"
#include "util.h" #include "util.h"
@ -58,6 +61,8 @@ enum {
typedef struct Context { typedef struct Context {
char *data[_PROP_MAX]; char *data[_PROP_MAX];
HostnameSource hostname_source;
struct stat etc_hostname_stat; struct stat etc_hostname_stat;
struct stat etc_os_release_stat; struct stat etc_os_release_stat;
struct stat etc_machine_info_stat; struct stat etc_machine_info_stat;
@ -66,11 +71,9 @@ typedef struct Context {
} Context; } Context;
static void context_reset(Context *c, uint64_t mask) { static void context_reset(Context *c, uint64_t mask) {
int p;
assert(c); assert(c);
for (p = 0; p < _PROP_MAX; p++) { for (int p = 0; p < _PROP_MAX; p++) {
if (!FLAGS_SET(mask, UINT64_C(1) << p)) if (!FLAGS_SET(mask, UINT64_C(1) << p))
continue; continue;
@ -312,63 +315,63 @@ static char* context_fallback_icon_name(Context *c) {
return strdup("computer"); return strdup("computer");
} }
static bool hostname_is_useful(const char *hn) {
return !isempty(hn) && !is_localhost(hn);
}
static int context_update_kernel_hostname( static int context_update_kernel_hostname(
Context *c, Context *c,
const char *transient_hn) { const char *transient_hn) {
const char *static_hn, *hn; const char *hn;
struct utsname u; HostnameSource hns;
int r;
assert(c); assert(c);
if (!transient_hn) { /* /etc/hostname has the highest preference ... */
/* If no transient hostname is passed in, then let's check what is currently set. */ if (c->data[PROP_STATIC_HOSTNAME]) {
assert_se(uname(&u) >= 0); hn = c->data[PROP_STATIC_HOSTNAME];
transient_hn = hns = HOSTNAME_STATIC;
isempty(u.nodename) || streq(u.nodename, "(none)") ? NULL : u.nodename;
}
static_hn = c->data[PROP_STATIC_HOSTNAME];
/* /etc/hostname with something other than "localhost"
* has the highest preference ... */
if (hostname_is_useful(static_hn))
hn = static_hn;
/* ... the transient hostname, (ie: DHCP) comes next ... */ /* ... the transient hostname, (ie: DHCP) comes next ... */
else if (!isempty(transient_hn)) } else if (transient_hn) {
hn = transient_hn; hn = transient_hn;
hns = HOSTNAME_TRANSIENT;
/* ... fallback to static "localhost.*" ignored above ... */
else if (!isempty(static_hn))
hn = static_hn;
/* ... and the ultimate fallback */ /* ... and the ultimate fallback */
else } else {
hn = FALLBACK_HOSTNAME; hn = FALLBACK_HOSTNAME;
hns = HOSTNAME_FALLBACK;
}
if (sethostname_idempotent(hn) < 0) r = sethostname_idempotent(hn);
return -errno; if (r < 0)
return log_error_errno(r, "Failed to set hostname: %m");
if (c->hostname_source != hns) {
c->hostname_source = hns;
r = 1;
}
(void) nscd_flush_cache(STRV_MAKE("hosts")); (void) nscd_flush_cache(STRV_MAKE("hosts"));
return 0; if (r == 0)
log_debug("Hostname was already set to <%s>.", hn);
else {
log_info("Hostname set to <%s> (%s)", hn, hostname_source_to_string(hns));
hostname_update_source_hint(hn, hns);
}
return r; /* 0 if no change, 1 if something was done */
} }
static int context_write_data_static_hostname(Context *c) { static int context_write_data_static_hostname(Context *c) {
assert(c); assert(c);
if (isempty(c->data[PROP_STATIC_HOSTNAME])) { if (isempty(c->data[PROP_STATIC_HOSTNAME])) {
if (unlink("/etc/hostname") < 0) if (unlink("/etc/hostname") < 0)
return errno == ENOENT ? 0 : -errno; return errno == ENOENT ? 0 : -errno;
return 0; return 0;
} }
return write_string_file_atomic_label("/etc/hostname", c->data[PROP_STATIC_HOSTNAME]); return write_string_file_atomic_label("/etc/hostname", c->data[PROP_STATIC_HOSTNAME]);
} }
@ -383,7 +386,7 @@ static int context_write_data_machine_info(Context *c) {
}; };
_cleanup_strv_free_ char **l = NULL; _cleanup_strv_free_ char **l = NULL;
int r, p; int r;
assert(c); assert(c);
@ -391,7 +394,7 @@ static int context_write_data_machine_info(Context *c) {
if (r < 0 && r != -ENOENT) if (r < 0 && r != -ENOENT)
return r; return r;
for (p = PROP_PRETTY_HOSTNAME; p <= PROP_LOCATION; p++) { for (int p = PROP_PRETTY_HOSTNAME; p <= PROP_LOCATION; p++) {
_cleanup_free_ char *t = NULL; _cleanup_free_ char *t = NULL;
char **u; char **u;
@ -461,6 +464,52 @@ static int property_get_static_hostname(
return sd_bus_message_append(reply, "s", c->data[PROP_STATIC_HOSTNAME]); return sd_bus_message_append(reply, "s", c->data[PROP_STATIC_HOSTNAME]);
} }
static BUS_DEFINE_PROPERTY_GET_GLOBAL(property_get_fallback_hostname, "s", FALLBACK_HOSTNAME);
static int property_get_hostname_source(
sd_bus *bus,
const char *path,
const char *interface,
const char *property,
sd_bus_message *reply,
void *userdata,
sd_bus_error *error) {
Context *c = userdata;
int r;
assert(c);
context_read_etc_hostname(c);
if (c->hostname_source < 0) {
char hostname[HOST_NAME_MAX + 1] = {};
_cleanup_free_ char *fallback = NULL;
(void) get_hostname_filtered(hostname);
if (streq_ptr(hostname, c->data[PROP_STATIC_HOSTNAME]))
c->hostname_source = HOSTNAME_STATIC;
else {
/* If the hostname was not set by us, try to figure out where it came from. If we set
* it to the fallback hostname, the file will tell us. We compare the string because
* it is possible that the hostname was set by an older version that had a different
* fallback, in the initramfs or before we reexecuted. */
r = read_one_line_file("/run/systemd/fallback-hostname", &fallback);
if (r < 0 && r != -ENOENT)
log_warning_errno(r, "Failed to read /run/systemd/fallback-hostname, ignoring: %m");
if (streq_ptr(fallback, hostname))
c->hostname_source = HOSTNAME_FALLBACK;
else
c->hostname_source = HOSTNAME_TRANSIENT;
}
}
return sd_bus_message_append(reply, "s", hostname_source_to_string(c->hostname_source));
}
static int property_get_machine_info_field( static int property_get_machine_info_field(
sd_bus *bus, sd_bus *bus,
const char *path, const char *path,
@ -579,7 +628,6 @@ static int method_set_hostname(sd_bus_message *m, void *userdata, sd_bus_error *
Context *c = userdata; Context *c = userdata;
const char *name; const char *name;
int interactive, r; int interactive, r;
struct utsname u;
assert(m); assert(m);
assert(c); assert(c);
@ -588,20 +636,15 @@ static int method_set_hostname(sd_bus_message *m, void *userdata, sd_bus_error *
if (r < 0) if (r < 0)
return r; return r;
context_read_etc_hostname(c); name = empty_to_null(name);
if (isempty(name)) /* We always go through with the procedure below without comparing to the current hostname, because
name = c->data[PROP_STATIC_HOSTNAME]; * we might want to adjust hostname source information even if the actual hostname is unchanged. */
if (isempty(name))
name = FALLBACK_HOSTNAME;
if (!hostname_is_valid(name, 0)) if (!hostname_is_valid(name, 0))
return sd_bus_error_setf(error, SD_BUS_ERROR_INVALID_ARGS, "Invalid hostname '%s'", name); return sd_bus_error_setf(error, SD_BUS_ERROR_INVALID_ARGS, "Invalid hostname '%s'", name);
assert_se(uname(&u) >= 0); context_read_etc_hostname(c);
if (streq_ptr(name, u.nodename))
return sd_bus_reply_method_return(m, NULL);
r = bus_verify_polkit_async( r = bus_verify_polkit_async(
m, m,
@ -618,14 +661,12 @@ static int method_set_hostname(sd_bus_message *m, void *userdata, sd_bus_error *
return 1; /* No authorization for now, but the async polkit stuff will call us again when it has it */ return 1; /* No authorization for now, but the async polkit stuff will call us again when it has it */
r = context_update_kernel_hostname(c, name); r = context_update_kernel_hostname(c, name);
if (r < 0) { if (r < 0)
log_error_errno(r, "Failed to set hostname: %m");
return sd_bus_error_set_errnof(error, r, "Failed to set hostname: %m"); return sd_bus_error_set_errnof(error, r, "Failed to set hostname: %m");
} else if (r > 0)
(void) sd_bus_emit_properties_changed(sd_bus_message_get_bus(m),
log_info("Changed hostname to '%s'", name); "/org/freedesktop/hostname1", "org.freedesktop.hostname1",
"Hostname", "HostnameSource", NULL);
(void) sd_bus_emit_properties_changed(sd_bus_message_get_bus(m), "/org/freedesktop/hostname1", "org.freedesktop.hostname1", "Hostname", NULL);
return sd_bus_reply_method_return(m, NULL); return sd_bus_reply_method_return(m, NULL);
} }
@ -650,7 +691,7 @@ static int method_set_static_hostname(sd_bus_message *m, void *userdata, sd_bus_
if (streq_ptr(name, c->data[PROP_STATIC_HOSTNAME])) if (streq_ptr(name, c->data[PROP_STATIC_HOSTNAME]))
return sd_bus_reply_method_return(m, NULL); return sd_bus_reply_method_return(m, NULL);
if (!isempty(name) && !hostname_is_valid(name, 0)) if (name && !hostname_is_valid(name, 0))
return sd_bus_error_setf(error, SD_BUS_ERROR_INVALID_ARGS, "Invalid static hostname '%s'", name); return sd_bus_error_setf(error, SD_BUS_ERROR_INVALID_ARGS, "Invalid static hostname '%s'", name);
r = bus_verify_polkit_async( r = bus_verify_polkit_async(
@ -671,21 +712,21 @@ static int method_set_static_hostname(sd_bus_message *m, void *userdata, sd_bus_
if (r < 0) if (r < 0)
return r; return r;
r = context_update_kernel_hostname(c, NULL);
if (r < 0) {
log_error_errno(r, "Failed to set hostname: %m");
return sd_bus_error_set_errnof(error, r, "Failed to set hostname: %m");
}
r = context_write_data_static_hostname(c); r = context_write_data_static_hostname(c);
if (r < 0) { if (r < 0) {
log_error_errno(r, "Failed to write static hostname: %m"); log_error_errno(r, "Failed to write static hostname: %m");
return sd_bus_error_set_errnof(error, r, "Failed to set static hostname: %m"); return sd_bus_error_set_errnof(error, r, "Failed to set static hostname: %m");
} }
log_info("Changed static hostname to '%s'", strna(c->data[PROP_STATIC_HOSTNAME])); r = context_update_kernel_hostname(c, NULL);
if (r < 0) {
log_error_errno(r, "Failed to set hostname: %m");
return sd_bus_error_set_errnof(error, r, "Failed to set hostname: %m");
}
(void) sd_bus_emit_properties_changed(sd_bus_message_get_bus(m), "/org/freedesktop/hostname1", "org.freedesktop.hostname1", "StaticHostname", NULL); (void) sd_bus_emit_properties_changed(sd_bus_message_get_bus(m),
"/org/freedesktop/hostname1", "org.freedesktop.hostname1",
"StaticHostname", "Hostname", "HostnameSource", NULL);
return sd_bus_reply_method_return(m, NULL); return sd_bus_reply_method_return(m, NULL);
} }
@ -850,6 +891,8 @@ static const sd_bus_vtable hostname_vtable[] = {
SD_BUS_PROPERTY("Hostname", "s", property_get_hostname, 0, SD_BUS_VTABLE_PROPERTY_EMITS_CHANGE), SD_BUS_PROPERTY("Hostname", "s", property_get_hostname, 0, SD_BUS_VTABLE_PROPERTY_EMITS_CHANGE),
SD_BUS_PROPERTY("StaticHostname", "s", property_get_static_hostname, 0, SD_BUS_VTABLE_PROPERTY_EMITS_CHANGE), SD_BUS_PROPERTY("StaticHostname", "s", property_get_static_hostname, 0, SD_BUS_VTABLE_PROPERTY_EMITS_CHANGE),
SD_BUS_PROPERTY("PrettyHostname", "s", property_get_machine_info_field, offsetof(Context, data) + sizeof(char*) * PROP_PRETTY_HOSTNAME, SD_BUS_VTABLE_PROPERTY_EMITS_CHANGE), SD_BUS_PROPERTY("PrettyHostname", "s", property_get_machine_info_field, offsetof(Context, data) + sizeof(char*) * PROP_PRETTY_HOSTNAME, SD_BUS_VTABLE_PROPERTY_EMITS_CHANGE),
SD_BUS_PROPERTY("FallbackHostname", "s", property_get_fallback_hostname, 0, SD_BUS_VTABLE_PROPERTY_CONST),
SD_BUS_PROPERTY("HostnameSource", "s", property_get_hostname_source, 0, SD_BUS_VTABLE_PROPERTY_EMITS_CHANGE),
SD_BUS_PROPERTY("IconName", "s", property_get_icon_name, 0, SD_BUS_VTABLE_PROPERTY_EMITS_CHANGE), SD_BUS_PROPERTY("IconName", "s", property_get_icon_name, 0, SD_BUS_VTABLE_PROPERTY_EMITS_CHANGE),
SD_BUS_PROPERTY("Chassis", "s", property_get_chassis, 0, SD_BUS_VTABLE_PROPERTY_EMITS_CHANGE), SD_BUS_PROPERTY("Chassis", "s", property_get_chassis, 0, SD_BUS_VTABLE_PROPERTY_EMITS_CHANGE),
SD_BUS_PROPERTY("Deployment", "s", property_get_machine_info_field, offsetof(Context, data) + sizeof(char*) * PROP_DEPLOYMENT, SD_BUS_VTABLE_PROPERTY_EMITS_CHANGE), SD_BUS_PROPERTY("Deployment", "s", property_get_machine_info_field, offsetof(Context, data) + sizeof(char*) * PROP_DEPLOYMENT, SD_BUS_VTABLE_PROPERTY_EMITS_CHANGE),
@ -960,7 +1003,9 @@ static int connect_bus(Context *c, sd_event *event, sd_bus **ret) {
} }
static int run(int argc, char *argv[]) { static int run(int argc, char *argv[]) {
_cleanup_(context_destroy) Context context = {}; _cleanup_(context_destroy) Context context = {
.hostname_source = _HOSTNAME_INVALID, /* appropriate value will be set later */
};
_cleanup_(sd_event_unrefp) sd_event *event = NULL; _cleanup_(sd_event_unrefp) sd_event *event = NULL;
_cleanup_(sd_bus_flush_close_unrefp) sd_bus *bus = NULL; _cleanup_(sd_bus_flush_close_unrefp) sd_bus *bus = NULL;
int r; int r;

1
src/network/networkd-dhcp4.c
View File

@ -8,6 +8,7 @@
#include "escape.h" #include "escape.h"
#include "alloc-util.h" #include "alloc-util.h"
#include "dhcp-client-internal.h" #include "dhcp-client-internal.h"
#include "hostname-setup.h"
#include "hostname-util.h" #include "hostname-util.h"
#include "parse-util.h" #include "parse-util.h"
#include "network-internal.h" #include "network-internal.h"

2
src/network/test-network.c
View File

@ -8,7 +8,7 @@
#include "alloc-util.h" #include "alloc-util.h"
#include "dhcp-lease-internal.h" #include "dhcp-lease-internal.h"
#include "ether-addr-util.h" #include "ether-addr-util.h"
#include "hostname-util.h" #include "hostname-setup.h"
#include "network-internal.h" #include "network-internal.h"
#include "networkd-manager.h" #include "networkd-manager.h"
#include "string-util.h" #include "string-util.h"

1
src/nspawn/nspawn.c
View File

@ -46,6 +46,7 @@
#include "fs-util.h" #include "fs-util.h"
#include "gpt.h" #include "gpt.h"
#include "hexdecoct.h" #include "hexdecoct.h"
#include "hostname-setup.h"
#include "hostname-util.h" #include "hostname-util.h"
#include "id128-util.h" #include "id128-util.h"
#include "io-util.h" #include "io-util.h"

2
src/shared/dissect-image.c
View File

@ -32,7 +32,7 @@
#include "fsck-util.h" #include "fsck-util.h"
#include "gpt.h" #include "gpt.h"
#include "hexdecoct.h" #include "hexdecoct.h"
#include "hostname-util.h" #include "hostname-setup.h"
#include "id128-util.h" #include "id128-util.h"
#include "mkdir.h" #include "mkdir.h"
#include "mount-util.h" #include "mount-util.h"

236
src/shared/hostname-setup.c Normal file
View File

@ -0,0 +1,236 @@
/* SPDX-License-Identifier: LGPL-2.1-or-later */
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/utsname.h>
#include <unistd.h>
#include "alloc-util.h"
#include "fd-util.h"
#include "fileio.h"
#include "fs-util.h"
#include "hostname-setup.h"
#include "hostname-util.h"
#include "log.h"
#include "macro.h"
#include "proc-cmdline.h"
#include "string-table.h"
#include "string-util.h"
#include "util.h"
static int sethostname_idempotent_full(const char *s, bool really) {
char buf[HOST_NAME_MAX + 1] = {};
assert(s);
if (gethostname(buf, sizeof(buf) - 1) < 0)
return -errno;
if (streq(buf, s))
return 0;
if (really &&
sethostname(s, strlen(s)) < 0)
return -errno;
return 1;
}
int sethostname_idempotent(const char *s) {
return sethostname_idempotent_full(s, true);
}
bool get_hostname_filtered(char ret[static HOST_NAME_MAX + 1]) {
char buf[HOST_NAME_MAX + 1] = {};
/* Returns true if we got a good hostname, false otherwise. */
if (gethostname(buf, sizeof(buf) - 1) < 0)
return false; /* This can realistically only fail with ENAMETOOLONG.
* Let's treat that case the same as an invalid hostname. */
if (isempty(buf))
return false;
/* This is the built-in kernel default hostname */
if (streq(buf, "(none)"))
return false;
memcpy(ret, buf, sizeof buf);
return true;
}
int shorten_overlong(const char *s, char **ret) {
char *h, *p;
/* Shorten an overlong name to HOST_NAME_MAX or to the first dot,
* whatever comes earlier. */
assert(s);
h = strdup(s);
if (!h)
return -ENOMEM;
if (hostname_is_valid(h, 0)) {
*ret = h;
return 0;
}
p = strchr(h, '.');
if (p)
*p = 0;
strshorten(h, HOST_NAME_MAX);
if (!hostname_is_valid(h, 0)) {
free(h);
return -EDOM;
}
*ret = h;
return 1;
}
int read_etc_hostname_stream(FILE *f, char **ret) {
int r;
assert(f);
assert(ret);
for (;;) {
_cleanup_free_ char *line = NULL;
char *p;
r = read_line(f, LONG_LINE_MAX, &line);
if (r < 0)
return r;
if (r == 0) /* EOF without any hostname? the file is empty, let's treat that exactly like no file at all: ENOENT */
return -ENOENT;
p = strstrip(line);
/* File may have empty lines or comments, ignore them */
if (!IN_SET(*p, '\0', '#')) {
char *copy;
hostname_cleanup(p); /* normalize the hostname */
if (!hostname_is_valid(p, VALID_HOSTNAME_TRAILING_DOT)) /* check that the hostname we return is valid */
return -EBADMSG;
copy = strdup(p);
if (!copy)
return -ENOMEM;
*ret = copy;
return 0;
}
}
}
int read_etc_hostname(const char *path, char **ret) {
_cleanup_fclose_ FILE *f = NULL;
assert(ret);
if (!path)
path = "/etc/hostname";
f = fopen(path, "re");
if (!f)
return -errno;
return read_etc_hostname_stream(f, ret);
}
void hostname_update_source_hint(const char *hostname, HostnameSource source) {
int r;
/* Why save the value and not just create a flag file? This way we will
* notice if somebody sets the hostname directly (not going through hostnamed).
*/
if (source == HOSTNAME_FALLBACK) {
r = write_string_file("/run/systemd/fallback-hostname", hostname,
WRITE_STRING_FILE_CREATE | WRITE_STRING_FILE_ATOMIC);
if (r < 0)
log_warning_errno(r, "Failed to create \"/run/systemd/fallback-hostname\": %m");
} else
unlink_or_warn("/run/systemd/fallback-hostname");
}
int hostname_setup(bool really) {
_cleanup_free_ char *b = NULL;
const char *hn = NULL;
HostnameSource source;
bool enoent = false;
int r;
r = proc_cmdline_get_key("systemd.hostname", 0, &b);
if (r < 0)
log_warning_errno(r, "Failed to retrieve system hostname from kernel command line, ignoring: %m");
else if (r > 0) {
if (hostname_is_valid(b, true)) {
hn = b;
source = HOSTNAME_TRANSIENT;
} else {
log_warning("Hostname specified on kernel command line is invalid, ignoring: %s", b);
b = mfree(b);
}
}
if (!hn) {
r = read_etc_hostname(NULL, &b);
if (r < 0) {
if (r == -ENOENT)
enoent = true;
else
log_warning_errno(r, "Failed to read configured hostname: %m");
} else {
hn = b;
source = HOSTNAME_STATIC;
}
}
if (isempty(hn)) {
/* Don't override the hostname if it is already set and not explicitly configured */
char buf[HOST_NAME_MAX + 1] = {};
if (get_hostname_filtered(buf)) {
log_debug("No hostname configured, leaving existing hostname <%s> in place.", buf);
return 0;
}
if (enoent)
log_info("No hostname configured, using fallback hostname.");
hn = FALLBACK_HOSTNAME;
source = HOSTNAME_FALLBACK;
}
r = sethostname_idempotent_full(hn, really);
if (r < 0)
return log_warning_errno(r, "Failed to set hostname to <%s>: %m", hn);
if (r == 0)
log_debug("Hostname was already set to <%s>.", hn);
else
log_info("Hostname %s to <%s>.",
really ? "set" : "would have been set",
hn);
if (really)
hostname_update_source_hint(hn, source);
return r;
}
static const char* const hostname_source_table[] = {
[HOSTNAME_STATIC] = "static",
[HOSTNAME_TRANSIENT] = "transient",
[HOSTNAME_FALLBACK] = "fallback",
};
DEFINE_STRING_TABLE_LOOKUP_TO_STRING(hostname_source, HostnameSource);

24
src/shared/hostname-setup.h Normal file
View File

@ -0,0 +1,24 @@
/* SPDX-License-Identifier: LGPL-2.1-or-later */
#pragma once
#include <stdbool.h>
#include <stdio.h>
typedef enum HostnameSource {
HOSTNAME_STATIC, /* from /etc/hostname */
HOSTNAME_TRANSIENT, /* a transient hostname set through systemd, hostnamed, the container manager, or otherwise */
HOSTNAME_FALLBACK, /* the compiled-in fallback was used */
_HOSTNAME_INVALID = -1,
} HostnameSource;
const char* hostname_source_to_string(HostnameSource source);
int sethostname_idempotent(const char *s);
int shorten_overlong(const char *s, char **ret);
int read_etc_hostname_stream(FILE *f, char **ret);
int read_etc_hostname(const char *path, char **ret);
bool get_hostname_filtered(char ret[static HOST_NAME_MAX + 1]);
void hostname_update_source_hint(const char *hostname, HostnameSource source);
int hostname_setup(bool really);

2
src/shared/machine-image.c
View File

@ -22,7 +22,7 @@
#include "fd-util.h" #include "fd-util.h"
#include "fs-util.h" #include "fs-util.h"
#include "hashmap.h" #include "hashmap.h"
#include "hostname-util.h" #include "hostname-setup.h"
#include "id128-util.h" #include "id128-util.h"
#include "lockfile-util.h" #include "lockfile-util.h"
#include "log.h" #include "log.h"

2
src/shared/meson.build
View File

@ -115,6 +115,8 @@ shared_sources = files('''
gpt.h gpt.h
group-record.c group-record.c
group-record.h group-record.h
hostname-setup.c
hostname-setup.h
id128-print.c id128-print.c
id128-print.h id128-print.h
idn-util.c idn-util.c

15
src/test/meson.build
View File

@ -105,17 +105,6 @@ tests += [
libmount, libmount,
libblkid]], libblkid]],
[['src/test/test-hostname.c'],
[libcore,
libshared],
[threads,
librt,
libseccomp,
libselinux,
libmount,
libblkid],
'', 'unsafe'],
[['src/test/test-dns-domain.c'], [['src/test/test-dns-domain.c'],
[libcore, [libcore,
libshared], libshared],
@ -339,6 +328,10 @@ tests += [
[], [],
[]], []],
[['src/test/test-hostname-setup.c'],
[],
[]],
[['src/test/test-hostname-util.c'], [['src/test/test-hostname-util.c'],
[], [],
[]], []],

72
src/test/test-hostname-setup.c Normal file
View File

@ -0,0 +1,72 @@
/* SPDX-License-Identifier: LGPL-2.1-or-later */
#include <unistd.h>
#include "alloc-util.h"
#include "fileio.h"
#include "hostname-setup.h"
#include "string-util.h"
#include "tests.h"
#include "tmpfile-util.h"
static void test_read_etc_hostname(void) {
char path[] = "/tmp/hostname.XXXXXX";
char *hostname;
int fd;
fd = mkostemp_safe(path);
assert(fd > 0);
close(fd);
/* simple hostname */
assert_se(write_string_file(path, "foo", WRITE_STRING_FILE_CREATE) == 0);
assert_se(read_etc_hostname(path, &hostname) == 0);
assert_se(streq(hostname, "foo"));
hostname = mfree(hostname);
/* with comment */
assert_se(write_string_file(path, "# comment\nfoo", WRITE_STRING_FILE_CREATE) == 0);
assert_se(read_etc_hostname(path, &hostname) == 0);
assert_se(hostname);
assert_se(streq(hostname, "foo"));
hostname = mfree(hostname);
/* with comment and extra whitespace */
assert_se(write_string_file(path, "# comment\n\n foo ", WRITE_STRING_FILE_CREATE) == 0);
assert_se(read_etc_hostname(path, &hostname) == 0);
assert_se(hostname);
assert_se(streq(hostname, "foo"));
hostname = mfree(hostname);
/* cleans up name */
assert_se(write_string_file(path, "!foo/bar.com", WRITE_STRING_FILE_CREATE) == 0);
assert_se(read_etc_hostname(path, &hostname) == 0);
assert_se(hostname);
assert_se(streq(hostname, "foobar.com"));
hostname = mfree(hostname);
/* no value set */
hostname = (char*) 0x1234;
assert_se(write_string_file(path, "# nothing here\n", WRITE_STRING_FILE_CREATE) == 0);
assert_se(read_etc_hostname(path, &hostname) == -ENOENT);
assert_se(hostname == (char*) 0x1234); /* does not touch argument on error */
/* nonexisting file */
assert_se(read_etc_hostname("/non/existing", &hostname) == -ENOENT);
assert_se(hostname == (char*) 0x1234); /* does not touch argument on error */
unlink(path);
}
static void test_hostname_setup(void) {
hostname_setup(false);
}
int main(int argc, char *argv[]) {
test_setup_logging(LOG_DEBUG);
test_read_etc_hostname();
test_hostname_setup();
return 0;
}

55
src/test/test-hostname-util.c
View File

@ -6,8 +6,8 @@
#include "fileio.h" #include "fileio.h"
#include "hostname-util.h" #include "hostname-util.h"
#include "string-util.h" #include "string-util.h"
#include "tests.h"
#include "tmpfile-util.h" #include "tmpfile-util.h"
#include "util.h"
static void test_hostname_is_valid(void) { static void test_hostname_is_valid(void) {
assert_se(hostname_is_valid("foobar", 0)); assert_se(hostname_is_valid("foobar", 0));
@ -91,55 +91,6 @@ static void test_hostname_cleanup(void) {
assert_se(streq(hostname_cleanup(s), "xxxx.xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx")); assert_se(streq(hostname_cleanup(s), "xxxx.xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx"));
} }
static void test_read_etc_hostname(void) {
char path[] = "/tmp/hostname.XXXXXX";
char *hostname;
int fd;
fd = mkostemp_safe(path);
assert(fd > 0);
close(fd);
/* simple hostname */
assert_se(write_string_file(path, "foo", WRITE_STRING_FILE_CREATE) == 0);
assert_se(read_etc_hostname(path, &hostname) == 0);
assert_se(streq(hostname, "foo"));
hostname = mfree(hostname);
/* with comment */
assert_se(write_string_file(path, "# comment\nfoo", WRITE_STRING_FILE_CREATE) == 0);
assert_se(read_etc_hostname(path, &hostname) == 0);
assert_se(hostname);
assert_se(streq(hostname, "foo"));
hostname = mfree(hostname);
/* with comment and extra whitespace */
assert_se(write_string_file(path, "# comment\n\n foo ", WRITE_STRING_FILE_CREATE) == 0);
assert_se(read_etc_hostname(path, &hostname) == 0);
assert_se(hostname);
assert_se(streq(hostname, "foo"));
hostname = mfree(hostname);
/* cleans up name */
assert_se(write_string_file(path, "!foo/bar.com", WRITE_STRING_FILE_CREATE) == 0);
assert_se(read_etc_hostname(path, &hostname) == 0);
assert_se(hostname);
assert_se(streq(hostname, "foobar.com"));
hostname = mfree(hostname);
/* no value set */
hostname = (char*) 0x1234;
assert_se(write_string_file(path, "# nothing here\n", WRITE_STRING_FILE_CREATE) == 0);
assert_se(read_etc_hostname(path, &hostname) == -ENOENT);
assert_se(hostname == (char*) 0x1234); /* does not touch argument on error */
/* nonexisting file */
assert_se(read_etc_hostname("/non/existing", &hostname) == -ENOENT);
assert_se(hostname == (char*) 0x1234); /* does not touch argument on error */
unlink(path);
}
static void test_hostname_malloc(void) { static void test_hostname_malloc(void) {
_cleanup_free_ char *h = NULL, *l = NULL; _cleanup_free_ char *h = NULL, *l = NULL;
@ -158,12 +109,10 @@ static void test_fallback_hostname(void) {
} }
int main(int argc, char *argv[]) { int main(int argc, char *argv[]) {
log_parse_environment(); test_setup_logging(LOG_INFO);
log_open();
test_hostname_is_valid(); test_hostname_is_valid();
test_hostname_cleanup(); test_hostname_cleanup();
test_read_etc_hostname();
test_hostname_malloc(); test_hostname_malloc();
test_fallback_hostname(); test_fallback_hostname();

14
src/test/test-hostname.c
View File

@ -1,14 +0,0 @@
/* SPDX-License-Identifier: LGPL-2.1-or-later */
#include "hostname-setup.h"
#include "util.h"
int main(int argc, char* argv[]) {
int r;
r = hostname_setup();
if (r < 0)
log_error_errno(r, "hostname: %m");
return 0;
}

2
units/systemd-hostnamed.service.in
View File

@ -32,7 +32,7 @@ ProtectKernelLogs=yes
ProtectKernelModules=yes ProtectKernelModules=yes
ProtectKernelTunables=yes ProtectKernelTunables=yes
ProtectSystem=strict ProtectSystem=strict
ReadWritePaths=/etc ReadWritePaths=/etc /run/systemd
RestrictAddressFamilies=AF_UNIX RestrictAddressFamilies=AF_UNIX
RestrictNamespaces=yes RestrictNamespaces=yes
RestrictRealtime=yes RestrictRealtime=yes