// SPDX-License-Identifier: GPL-2.0+
/*
* Copyright (C) 2017 Red Hat, Inc.
*/
#include "nm-default.h"
#include "nm-hostname-manager.h"
#include <sys/stat.h>
#if HAVE_SELINUX
#include <selinux/selinux.h>
#endif
#include "nm-libnm-core-intern/nm-common-macros.h"
#include "nm-dbus-interface.h"
#include "nm-connection.h"
#include "nm-utils.h"
#include "nm-core-internal.h"
#include "NetworkManagerUtils.h"
/*****************************************************************************/
#define HOSTNAMED_SERVICE_NAME "org.freedesktop.hostname1"
#define HOSTNAMED_SERVICE_PATH "/org/freedesktop/hostname1"
#define HOSTNAMED_SERVICE_INTERFACE "org.freedesktop.hostname1"
#define HOSTNAME_FILE_DEFAULT "/etc/hostname"
#define HOSTNAME_FILE_UCASE_HOSTNAME "/etc/HOSTNAME"
#define HOSTNAME_FILE_GENTOO "/etc/conf.d/hostname"
#define CONF_DHCP SYSCONFDIR "/sysconfig/network/dhcp"
#if (defined(HOSTNAME_PERSIST_SUSE) + defined(HOSTNAME_PERSIST_SLACKWARE) + defined(HOSTNAME_PERSIST_GENTOO)) > 1
#error "Can only define one of HOSTNAME_PERSIST_*"
#endif
#if defined(HOSTNAME_PERSIST_SUSE)
#define HOSTNAME_FILE HOSTNAME_FILE_UCASE_HOSTNAME
#elif defined(HOSTNAME_PERSIST_SLACKWARE)
#define HOSTNAME_FILE HOSTNAME_FILE_UCASE_HOSTNAME
#elif defined(HOSTNAME_PERSIST_GENTOO)
#define HOSTNAME_FILE HOSTNAME_FILE_GENTOO
#else
#define HOSTNAME_FILE HOSTNAME_FILE_DEFAULT
#endif
/*****************************************************************************/
NM_GOBJECT_PROPERTIES_DEFINE (NMHostnameManager,
PROP_HOSTNAME,
);
typedef struct {
char *current_hostname;
GFileMonitor *monitor;
GFileMonitor *dhcp_monitor;
gulong monitor_id;
gulong dhcp_monitor_id;
GDBusProxy *hostnamed_proxy;
} NMHostnameManagerPrivate;
struct _NMHostnameManager {
GObject parent;
NMHostnameManagerPrivate _priv;
};
struct _NMHostnameManagerClass {
GObjectClass parent;
};
G_DEFINE_TYPE (NMHostnameManager, nm_hostname_manager, G_TYPE_OBJECT);
#define NM_HOSTNAME_MANAGER_GET_PRIVATE(self) _NM_GET_PRIVATE (self, NMHostnameManager, NM_IS_HOSTNAME_MANAGER)
NM_DEFINE_SINGLETON_GETTER (NMHostnameManager, nm_hostname_manager_get, NM_TYPE_HOSTNAME_MANAGER);
/*****************************************************************************/
#define _NMLOG_DOMAIN LOGD_CORE
#define _NMLOG(level, ...) __NMLOG_DEFAULT (level, _NMLOG_DOMAIN, "hostname", __VA_ARGS__)
/*****************************************************************************/
#if defined(HOSTNAME_PERSIST_GENTOO)
static char *
read_hostname_gentoo (const char *path)
{
gs_free char *contents = NULL;
gs_strfreev char **all_lines = NULL;
const char *tmp;
guint i;
if (!g_file_get_contents (path, &contents, NULL, NULL))
return NULL;
all_lines = g_strsplit (contents, "\n", 0);
for (i = 0; all_lines[i]; i++) {
g_strstrip (all_lines[i]);
if (all_lines[i][0] == '#' || all_lines[i][0] == '\0')
continue;
if (g_str_has_prefix (all_lines[i], "hostname=")) {
tmp = &all_lines[i][NM_STRLEN ("hostname=")];
return g_shell_unquote (tmp, NULL);
}
}
return NULL;
}
#endif
#if defined(HOSTNAME_PERSIST_SLACKWARE)
static char *
read_hostname_slackware (const char *path)
{
gs_free char *contents = NULL;
gs_strfreev char **all_lines = NULL;
guint i = 0;
if (!g_file_get_contents (path, &contents, NULL, NULL))
return NULL;
all_lines = g_strsplit (contents, "\n", 0);
for (i = 0; all_lines[i]; i++) {
g_strstrip (all_lines[i]);
if (all_lines[i][0] == '#' || all_lines[i][0] == '\0')
continue;
return g_shell_unquote (&all_lines[i][0], NULL);
}
return NULL;
}
#endif
#if defined(HOSTNAME_PERSIST_SUSE)
static gboolean
hostname_is_dynamic (void)
{
GIOChannel *channel;
char *str = NULL;
gboolean dynamic = FALSE;
channel = g_io_channel_new_file (CONF_DHCP, "r", NULL);
if (!channel)
return dynamic;
while (g_io_channel_read_line (channel, &str, NULL, NULL, NULL) != G_IO_STATUS_EOF) {
if (str) {
g_strstrip (str);
if (g_str_has_prefix (str, "DHCLIENT_SET_HOSTNAME="))
dynamic = strcmp (&str[NM_STRLEN ("DHCLIENT_SET_HOSTNAME=")], "\"yes\"") == 0;
g_free (str);
}
}
g_io_channel_shutdown (channel, FALSE, NULL);
g_io_channel_unref (channel);
return dynamic;
}
#endif
/* Returns an allocated string which the caller owns and must eventually free */
char *
nm_hostname_manager_read_hostname (NMHostnameManager *self)
{
NMHostnameManagerPrivate *priv = NM_HOSTNAME_MANAGER_GET_PRIVATE (self);
char *hostname = NULL;
if (priv->hostnamed_proxy) {
hostname = g_strdup (priv->current_hostname);
goto out;
}
#if defined(HOSTNAME_PERSIST_SUSE)
if (priv->dhcp_monitor_id && hostname_is_dynamic ())
return NULL;
#endif
#if defined(HOSTNAME_PERSIST_GENTOO)
hostname = read_hostname_gentoo (HOSTNAME_FILE);
#elif defined(HOSTNAME_PERSIST_SLACKWARE)
hostname = read_hostname_slackware (HOSTNAME_FILE);
#else
if (g_file_get_contents (HOSTNAME_FILE, &hostname, NULL, NULL))
g_strchomp (hostname);
#endif
out:
if (hostname && !hostname[0]) {
g_free (hostname);
return NULL;
}
return hostname;
}
/*****************************************************************************/
const char *
nm_hostname_manager_get_hostname (NMHostnameManager *self)
{
g_return_val_if_fail (NM_IS_HOSTNAME_MANAGER (self), NULL);
return NM_HOSTNAME_MANAGER_GET_PRIVATE (self)->current_hostname;
}
static void
_set_hostname_take (NMHostnameManager *self, char *hostname)
{
NMHostnameManagerPrivate *priv = NM_HOSTNAME_MANAGER_GET_PRIVATE (self);
_LOGI ("hostname changed from %s%s%s to %s%s%s",
NM_PRINT_FMT_QUOTED (priv->current_hostname, "\"", priv->current_hostname, "\"", "(none)"),
NM_PRINT_FMT_QUOTED (hostname, "\"", hostname, "\"", "(none)"));
g_free (priv->current_hostname);
priv->current_hostname = hostname;
_notify (self, PROP_HOSTNAME);
}
static void
_set_hostname (NMHostnameManager *self, const char *hostname)
{
NMHostnameManagerPrivate *priv = NM_HOSTNAME_MANAGER_GET_PRIVATE (self);
hostname = nm_str_not_empty (hostname);
if (!nm_streq0 (hostname, priv->current_hostname))
_set_hostname_take (self, g_strdup (hostname));
}
static void
_set_hostname_read (NMHostnameManager *self)
{
NMHostnameManagerPrivate *priv = NM_HOSTNAME_MANAGER_GET_PRIVATE (self);
char *hostname;
if (priv->hostnamed_proxy) {
/* read-hostname returns the current hostname with hostnamed. */
return;
}
hostname = nm_hostname_manager_read_hostname (self);
if (nm_streq0 (hostname, priv->current_hostname)) {
g_free (hostname);
return;
}
_set_hostname_take (self, hostname);
}
/*****************************************************************************/
typedef struct {
char *hostname;
NMHostnameManagerSetHostnameCb cb;
gpointer user_data;
} SetHostnameInfo;
static void
set_transient_hostname_done (GObject *object,
GAsyncResult *res,
gpointer user_data)
{
GDBusProxy *proxy = G_DBUS_PROXY (object);
gs_free SetHostnameInfo *info = user_data;
gs_unref_variant GVariant *result = NULL;
gs_free_error GError *error = NULL;
result = g_dbus_proxy_call_finish (proxy, res, &error);
if (error) {
_LOGW ("couldn't set the system hostname to '%s' using hostnamed: %s",
info->hostname, error->message);
}
info->cb (info->hostname, !error, info->user_data);
g_free (info->hostname);
}
void
nm_hostname_manager_set_transient_hostname (NMHostnameManager *self,
const char *hostname,
NMHostnameManagerSetHostnameCb cb,
gpointer user_data)
{
NMHostnameManagerPrivate *priv;
SetHostnameInfo *info;
g_return_if_fail (NM_IS_HOSTNAME_MANAGER (self));
priv = NM_HOSTNAME_MANAGER_GET_PRIVATE (self);
if (!priv->hostnamed_proxy) {
cb (hostname, FALSE, user_data);
return;
}
info = g_new0 (SetHostnameInfo, 1);
info->hostname = g_strdup (hostname);
info->cb = cb;
info->user_data = user_data;
g_dbus_proxy_call (priv->hostnamed_proxy,
"SetHostname",
g_variant_new ("(sb)", hostname, FALSE),
G_DBUS_CALL_FLAGS_NONE,
-1,
NULL,
set_transient_hostname_done,
info);
}
gboolean
nm_hostname_manager_get_transient_hostname (NMHostnameManager *self, char **hostname)
{
NMHostnameManagerPrivate *priv = NM_HOSTNAME_MANAGER_GET_PRIVATE (self);
GVariant *v_hostname;
if (!priv->hostnamed_proxy)
return FALSE;
v_hostname = g_dbus_proxy_get_cached_property (priv->hostnamed_proxy,
"Hostname");
if (!v_hostname) {
_LOGT ("transient hostname retrieval failed");
return FALSE;
}
*hostname = g_variant_dup_string (v_hostname, NULL);
g_variant_unref (v_hostname);
return TRUE;
}
gboolean
nm_hostname_manager_write_hostname (NMHostnameManager *self, const char *hostname)
{
NMHostnameManagerPrivate *priv;
char *hostname_eol;
gboolean ret;
gs_free_error GError *error = NULL;
const char *file = HOSTNAME_FILE;
gs_free char *link_path = NULL;
gs_unref_variant GVariant *var = NULL;
struct stat file_stat;
#if HAVE_SELINUX
security_context_t se_ctx_prev = NULL, se_ctx = NULL;
mode_t st_mode = 0;
#endif
g_return_val_if_fail (NM_IS_HOSTNAME_MANAGER (self), FALSE);
priv = NM_HOSTNAME_MANAGER_GET_PRIVATE (self);
if (priv->hostnamed_proxy) {
var = g_dbus_proxy_call_sync (priv->hostnamed_proxy,
"SetStaticHostname",
g_variant_new ("(sb)", hostname, FALSE),
G_DBUS_CALL_FLAGS_NONE,
-1,
NULL,
&error);
if (error)
_LOGW ("could not set hostname: %s", error->message);
return !error;
}
/* If the hostname file is a symbolic link, follow it to find where the
* real file is located, otherwise g_file_set_contents will attempt to
* replace the link with a plain file.
*/
if ( lstat (file, &file_stat) == 0
&& S_ISLNK (file_stat.st_mode)
&& (link_path = nm_utils_read_link_absolute (file, NULL)))
file = link_path;
#if HAVE_SELINUX
/* Get default context for hostname file and set it for fscreate */
if (stat (file, &file_stat) == 0)
st_mode = file_stat.st_mode;
matchpathcon (file, st_mode, &se_ctx);
matchpathcon_fini ();
getfscreatecon (&se_ctx_prev);
setfscreatecon (se_ctx);
#endif
#if defined (HOSTNAME_PERSIST_GENTOO)
hostname_eol = g_strdup_printf ("#Generated by NetworkManager\n"
"hostname=\"%s\"\n", hostname);
#else
hostname_eol = g_strdup_printf ("%s\n", hostname);
#endif
ret = g_file_set_contents (file, hostname_eol, -1, &error);
#if HAVE_SELINUX
/* Restore previous context and cleanup */
setfscreatecon (se_ctx_prev);
freecon (se_ctx);
freecon (se_ctx_prev);
#endif
g_free (hostname_eol);
if (!ret) {
_LOGW ("could not save hostname to %s: %s", file, error->message);
return FALSE;
}
return TRUE;
}
gboolean
nm_hostname_manager_validate_hostname (const char *hostname)
{
const char *p;
gboolean dot = TRUE;
if (!hostname || !hostname[0])
return FALSE;
for (p = hostname; *p; p++) {
if (*p == '.') {
if (dot)
return FALSE;
dot = TRUE;
} else {
if (!g_ascii_isalnum (*p) && (*p != '-') && (*p != '_'))
return FALSE;
dot = FALSE;
}
}
if (dot)
return FALSE;
return (p - hostname <= HOST_NAME_MAX);
}
static void
hostname_file_changed_cb (GFileMonitor *monitor,
GFile *file,
GFile *other_file,
GFileMonitorEvent event_type,
gpointer user_data)
{
_set_hostname_read (user_data);
}
/*****************************************************************************/
static void
hostnamed_properties_changed (GDBusProxy *proxy,
GVariant *changed_properties,
char **invalidated_properties,
gpointer user_data)
{
NMHostnameManager *self = user_data;
NMHostnameManagerPrivate *priv = NM_HOSTNAME_MANAGER_GET_PRIVATE (self);
GVariant *v_hostname;
v_hostname = g_dbus_proxy_get_cached_property (priv->hostnamed_proxy,
"StaticHostname");
if (v_hostname) {
_set_hostname (self, g_variant_get_string (v_hostname, NULL));
g_variant_unref (v_hostname);
}
}
static void
setup_hostname_file_monitors (NMHostnameManager *self)
{
NMHostnameManagerPrivate *priv = NM_HOSTNAME_MANAGER_GET_PRIVATE (self);
GFileMonitor *monitor;
const char *path = HOSTNAME_FILE;
char *link_path = NULL;
struct stat file_stat;
GFile *file;
/* resolve the path to the hostname file if it is a symbolic link */
if ( lstat(path, &file_stat) == 0
&& S_ISLNK (file_stat.st_mode)
&& (link_path = nm_utils_read_link_absolute (path, NULL))) {
path = link_path;
if ( lstat(link_path, &file_stat) == 0
&& S_ISLNK (file_stat.st_mode)) {
_LOGW ("only one level of symbolic link indirection is allowed when monitoring "
HOSTNAME_FILE);
}
}
/* monitor changes to hostname file */
file = g_file_new_for_path (path);
monitor = g_file_monitor_file (file, G_FILE_MONITOR_NONE, NULL, NULL);
g_object_unref (file);
g_free(link_path);
if (monitor) {
priv->monitor_id = g_signal_connect (monitor, "changed",
G_CALLBACK (hostname_file_changed_cb),
self);
priv->monitor = monitor;
}
#if defined (HOSTNAME_PERSIST_SUSE)
/* monitor changes to dhcp file to know whether the hostname is valid */
file = g_file_new_for_path (CONF_DHCP);
monitor = g_file_monitor_file (file, G_FILE_MONITOR_NONE, NULL, NULL);
g_object_unref (file);
if (monitor) {
priv->dhcp_monitor_id = g_signal_connect (monitor, "changed",
G_CALLBACK (hostname_file_changed_cb),
self);
priv->dhcp_monitor = monitor;
}
#endif
_set_hostname_read (self);
}
/*****************************************************************************/
static void
get_property (GObject *object, guint prop_id,
GValue *value, GParamSpec *pspec)
{
NMHostnameManager *self = NM_HOSTNAME_MANAGER (object);
switch (prop_id) {
case PROP_HOSTNAME:
g_value_set_string (value, nm_hostname_manager_get_hostname (self));
break;
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
break;
}
}
/*****************************************************************************/
static void
nm_hostname_manager_init (NMHostnameManager *self)
{
}
static void
constructed (GObject *object)
{
NMHostnameManager *self = NM_HOSTNAME_MANAGER (object);
NMHostnameManagerPrivate *priv = NM_HOSTNAME_MANAGER_GET_PRIVATE (self);
GDBusProxy *proxy;
GVariant *variant;
gs_free_error GError *error = NULL;
proxy = g_dbus_proxy_new_for_bus_sync (G_BUS_TYPE_SYSTEM, 0, NULL,
HOSTNAMED_SERVICE_NAME, HOSTNAMED_SERVICE_PATH,
HOSTNAMED_SERVICE_INTERFACE, NULL, &error);
if (proxy) {
variant = g_dbus_proxy_get_cached_property (proxy, "StaticHostname");
if (variant) {
_LOGI ("hostname: using hostnamed");
priv->hostnamed_proxy = proxy;
g_signal_connect (proxy, "g-properties-changed",
G_CALLBACK (hostnamed_properties_changed), self);
hostnamed_properties_changed (proxy, NULL, NULL, self);
g_variant_unref (variant);
} else {
_LOGI ("hostname: couldn't get property from hostnamed");
g_object_unref (proxy);
}
} else {
_LOGI ("hostname: hostnamed not used as proxy creation failed with: %s",
error->message);
g_clear_error (&error);
}
if (!priv->hostnamed_proxy)
setup_hostname_file_monitors (self);
G_OBJECT_CLASS (nm_hostname_manager_parent_class)->constructed (object);
}
static void
dispose (GObject *object)
{
NMHostnameManager *self = NM_HOSTNAME_MANAGER (object);
NMHostnameManagerPrivate *priv = NM_HOSTNAME_MANAGER_GET_PRIVATE (self);
if (priv->hostnamed_proxy) {
g_signal_handlers_disconnect_by_func (priv->hostnamed_proxy,
G_CALLBACK (hostnamed_properties_changed),
self);
g_clear_object (&priv->hostnamed_proxy);
}
if (priv->monitor) {
if (priv->monitor_id)
g_signal_handler_disconnect (priv->monitor, priv->monitor_id);
g_file_monitor_cancel (priv->monitor);
g_clear_object (&priv->monitor);
}
if (priv->dhcp_monitor) {
if (priv->dhcp_monitor_id)
g_signal_handler_disconnect (priv->dhcp_monitor,
priv->dhcp_monitor_id);
g_file_monitor_cancel (priv->dhcp_monitor);
g_clear_object (&priv->dhcp_monitor);
}
nm_clear_g_free (&priv->current_hostname);
G_OBJECT_CLASS (nm_hostname_manager_parent_class)->dispose (object);
}
static void
nm_hostname_manager_class_init (NMHostnameManagerClass *class)
{
GObjectClass *object_class = G_OBJECT_CLASS (class);
object_class->constructed = constructed;
object_class->get_property = get_property;
object_class->dispose = dispose;
obj_properties[PROP_HOSTNAME] =
g_param_spec_string (NM_HOSTNAME_MANAGER_HOSTNAME, "", "",
NULL,
G_PARAM_READABLE |
G_PARAM_STATIC_STRINGS);
g_object_class_install_properties (object_class, _PROPERTY_ENUMS_LAST, obj_properties);
}