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core: add DBUS method to bind mount new nodes without service restart

Browse source 
Allow to setup new bind mounts for a service at runtime (via either
DBUS or a new 'systemctl bind' verb) with a new helper that forks into
the unit's mount namespace.
Add a new integration test to cover this.

Useful for zero-downtime addition to services that are running inside
mount namespaces, especially when using RootImage/RootDirectory.

If a service runs with a read-only root, a tmpfs is added on /run
to ensure we can create the airlock directory for incoming mounts
under /run/host/incoming.
This commit is contained in:
Luca Boccassi 2020-07-30 19:37:10 +01:00
parent 94293d65cd
commit 5e8deb94c6
29 changed files with 415 additions and 40 deletions
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27
man/org.freedesktop.systemd1.xml
View file

@ -116,6 +116,11 @@ node /org/freedesktop/systemd1 {
SetUnitProperties(in s name,
in b runtime,
in a(sv) properties);
BindMountUnit(in s name,
in s source,
in s destination,
in b read_only,
in b mkdir);
RefUnit(in s name);
UnrefUnit(in s name);
StartTransientUnit(in s name,
@ -767,6 +772,8 @@ node /org/freedesktop/systemd1 {
<variablelist class="dbus-method" generated="True" extra-ref="SetUnitProperties()"/>
<variablelist class="dbus-method" generated="True" extra-ref="BindMountUnit()"/>
<variablelist class="dbus-method" generated="True" extra-ref="RefUnit()"/>
<variablelist class="dbus-method" generated="True" extra-ref="UnrefUnit()"/>
@ -1156,6 +1163,9 @@ node /org/freedesktop/systemd1 {
the "Try" flavor is used in which case a service that isn't running is not affected by the restart. The
"ReloadOrRestart" flavors attempt a reload if the unit supports it and use a restart otherwise.</para>
<para><function>BindMountUnit()</function> can be used to bind mount new files or directories into
a running service mount namespace.</para>
<para><function>KillUnit()</function> may be used to kill (i.e. send a signal to) all processes of a
unit. It takes the unit <varname>name</varname>, an enum <varname>who</varname> and a UNIX
<varname>signal</varname> number to send. The <varname>who</varname> enum is one of
@ -2193,6 +2203,10 @@ node /org/freedesktop/systemd1/unit/avahi_2ddaemon_2eservice {
node /org/freedesktop/systemd1/unit/avahi_2ddaemon_2eservice {
interface org.freedesktop.systemd1.Service {
methods:
BindMount(in s source,
in s destination,
in b read_only,
in b mkdir);
GetProcesses(out a(sus) processes);
AttachProcesses(in s subcgroup,
in au pids);
@ -3252,6 +3266,8 @@ node /org/freedesktop/systemd1/unit/avahi_2ddaemon_2eservice {
<variablelist class="dbus-interface" generated="True" extra-ref="org.freedesktop.systemd1.Service"/>
<variablelist class="dbus-method" generated="True" extra-ref="BindMount()"/>
<variablelist class="dbus-method" generated="True" extra-ref="GetProcesses()"/>
<variablelist class="dbus-method" generated="True" extra-ref="AttachProcesses()"/>
@ -3810,6 +3826,17 @@ node /org/freedesktop/systemd1/unit/avahi_2ddaemon_2eservice {
<!--End of Autogenerated section-->
<refsect2>
<title>Methods</title>
<para><function>BindMount()</function> implements the same operation as the respective method on the
<interfacename>Manager</interfacename> object (see above). However, this method operates on the service
object and hence does not take a unit name parameter. Invoking the methods directly on the Manager
object has the advantage of not requiring a <function>GetUnit()</function> call to get the unit object
for a specific unit name. Calling the methods on the Manager object is hence a round trip
optimization.</para>
</refsect2>
<refsect2>
<title>Properties</title>

32
man/systemctl.xml
View file

@ -550,6 +550,23 @@ Jan 12 10:46:45 example.com bluetoothd[8900]: gatt-time-server: Input/output err
</listitem>
</varlistentry>
<varlistentry>
<term><command>bind</command> <replaceable>UNIT</replaceable> <replaceable>PATH</replaceable> [<replaceable>PATH</replaceable>]</term>
<listitem><para>Bind mounts a file or directory from the host into the specified unit's view. The first path
argument is the source file or directory on the host, the second path argument is the destination file or
directory in the unit's view. When the latter is omitted, the destination path in the unit's view is the same as
the source path on the host. When combined with the <option>--read-only</option> switch, a ready-only bind
mount is created. When combined with the <option>--mkdir</option> switch, the destination path is first created
before the mount is applied. Note that this option is currently only supported for units that run within a mount
namespace (e.g.: with <option>RootImage=</option>, <option>PrivateMounts=</option>, etc.). This command supports bind
mounting directories, regular files, device nodes, <constant>AF_UNIX</constant> socket nodes, as well as FIFOs.
The bind mount is ephemeral, and it is undone as soon as the current unit process exists.
Note that the namespace mentioned here, where the bind mount will be added to, is the one where the main service
process runs, as other processes run in distinct namespaces (e.g.: <option>ExecReload=</option>,
<option>ExecStartPre=</option>, etc.) </para></listitem>
</varlistentry>
<varlistentry>
<term><command>service-log-level</command> <replaceable>SERVICE</replaceable> [<replaceable>LEVEL</replaceable>]</term>
@ -2246,6 +2263,21 @@ Jan 12 10:46:45 example.com bluetoothd[8900]: gatt-time-server: Input/output err
</listitem>
</varlistentry>
<varlistentry>
<term><option>--mkdir</option></term>
<listitem><para>When used with <command>bind</command>, creates the destination file or directory before
applying the bind mount. Note that even though the name of this option suggests that it is suitable only for
directories, this option also creates the destination file node to mount over if the object to mount is not
a directory, but a regular file, device node, socket or FIFO.</para></listitem>
</varlistentry>
<varlistentry>
<term><option>--read-only</option></term>
<listitem><para>When used with <command>bind</command>, creates a read-only bind mount.</para></listitem>
</varlistentry>
<xi:include href="user-system-options.xml" xpointer="host" />
<xi:include href="user-system-options.xml" xpointer="machine" />

4
man/systemd.exec.xml
View file

@ -285,6 +285,10 @@
the service with a private, minimal version of <filename>/dev/</filename>, combine this option with
<varname>PrivateDevices=</varname>.</para>
<para>In order to allow propagating mounts at runtime in a safe manner, <filename>/run/systemd/propagate</filename>
on the host will be used to set up new mounts, and <filename>/run/host/incoming/</filename> in the private namespace
will be used as an intermediate step to store them before being moved to the final mount point.</para>
<xi:include href="system-only.xml" xpointer="singular"/></listitem>
</varlistentry>

2
meson.build
View file

@ -2198,6 +2198,8 @@ public_programs += executable(
'src/systemctl/systemctl-log-setting.h',
'src/systemctl/systemctl-logind.c',
'src/systemctl/systemctl-logind.h',
'src/systemctl/systemctl-mount.c',
'src/systemctl/systemctl-mount.h',
'src/systemctl/systemctl-preset-all.c',
'src/systemctl/systemctl-preset-all.h',
'src/systemctl/systemctl-reset-failed.c',

2
shell-completion/bash/systemctl.in
View file

@ -214,7 +214,7 @@ _systemctl () {
list-timers list-units list-unit-files poweroff
reboot rescue show-environment suspend get-default
is-system-running preset-all'
[FILE]='link switch-root'
[FILE]='link switch-root bind'
[TARGETS]='set-default'
[MACHINES]='list-machines'
[LOG_LEVEL]='log-level'

5
shell-completion/zsh/_systemctl.in
View file

@ -31,6 +31,7 @@
"reset-failed:Reset failed state for all, one, or more units"
"list-dependencies:Show unit dependency tree"
"clean:Remove configuration, state, cache, logs or runtime data of units"
"bind:Bind mount a path from the host into a unit's namespace"
)
local -a machine_commands=(
@ -378,6 +379,10 @@ done
_files
}
(( $+functions[_systemctl_bind] )) || _systemctl_bind() {
_files
}
# no systemctl completion for:
# [STANDALONE]='daemon-reexec daemon-reload default
# emergency exit halt kexec list-jobs list-units

16
src/core/dbus-manager.c
View file

@ -16,6 +16,7 @@
#include "dbus-job.h"
#include "dbus-manager.h"
#include "dbus-scope.h"
#include "dbus-service.h"
#include "dbus-unit.h"
#include "dbus.h"
#include "env-util.h"
@ -725,6 +726,11 @@ static int method_set_unit_properties(sd_bus_message *message, void *userdata, s
return method_generic_unit_operation(message, userdata, error, bus_unit_method_set_properties, GENERIC_UNIT_LOAD|GENERIC_UNIT_VALIDATE_LOADED);
}
static int method_bind_mount_unit(sd_bus_message *message, void *userdata, sd_bus_error *error) {
/* Only add mounts on fully loaded units */
return method_generic_unit_operation(message, userdata, error, bus_service_method_bind_mount, GENERIC_UNIT_VALIDATE_LOADED);
}
static int method_ref_unit(sd_bus_message *message, void *userdata, sd_bus_error *error) {
/* Only allow reffing of fully loaded units, and make sure reffing a unit loads it. */
return method_generic_unit_operation(message, userdata, error, bus_unit_method_ref, GENERIC_UNIT_LOAD|GENERIC_UNIT_VALIDATE_LOADED);
@ -2760,6 +2766,16 @@ const sd_bus_vtable bus_manager_vtable[] = {
NULL,,
method_set_unit_properties,
SD_BUS_VTABLE_UNPRIVILEGED),
SD_BUS_METHOD_WITH_NAMES("BindMountUnit",
"sssbb",
SD_BUS_PARAM(name)
SD_BUS_PARAM(source)
SD_BUS_PARAM(destination)
SD_BUS_PARAM(read_only)
SD_BUS_PARAM(mkdir),
NULL,,
method_bind_mount_unit,
SD_BUS_VTABLE_UNPRIVILEGED),
SD_BUS_METHOD_WITH_NAMES("RefUnit",
"s",
SD_BUS_PARAM(name),

87
src/core/dbus-service.c
View file

@ -11,11 +11,15 @@
#include "dbus-manager.h"
#include "dbus-service.h"
#include "dbus-util.h"
#include "execute.h"
#include "exit-status.h"
#include "fd-util.h"
#include "fileio.h"
#include "locale-util.h"
#include "mount-util.h"
#include "parse-util.h"
#include "path-util.h"
#include "selinux-access.h"
#include "service.h"
#include "signal-util.h"
#include "string-util.h"
@ -91,6 +95,79 @@ static int property_get_exit_status_set(
return sd_bus_message_close_container(reply);
}
int bus_service_method_bind_mount(sd_bus_message *message, void *userdata, sd_bus_error *error) {
int read_only, make_file_or_directory;
const char *dest, *src, *propagate_directory;
Unit *u = userdata;
ExecContext *c;
pid_t unit_pid;
int r;
assert(message);
assert(u);
if (!MANAGER_IS_SYSTEM(u->manager))
return sd_bus_error_setf(error, SD_BUS_ERROR_NOT_SUPPORTED, "Adding bind mounts at runtime is only supported for system managers.");
r = mac_selinux_unit_access_check(u, message, "start", error);
if (r < 0)
return r;
r = sd_bus_message_read(message, "ssbb", &src, &dest, &read_only, &make_file_or_directory);
if (r < 0)
return r;
if (!path_is_absolute(src) || !path_is_normalized(src))
return sd_bus_error_setf(error, SD_BUS_ERROR_INVALID_ARGS, "Source path must be absolute and normalized.");
if (isempty(dest))
dest = src;
else if (!path_is_absolute(dest) || !path_is_normalized(dest))
return sd_bus_error_setf(error, SD_BUS_ERROR_INVALID_ARGS, "Destination path must be absolute and normalized.");
r = bus_verify_manage_units_async_full(
u,
"bind-mount",
CAP_SYS_ADMIN,
N_("Authentication is required to bind mount on '$(unit)'."),
true,
message,
error);
if (r < 0)
return r;
if (r == 0)
return 1; /* No authorization for now, but the async polkit stuff will call us again when it has it */
if (u->type != UNIT_SERVICE)
return sd_bus_error_setf(error, SD_BUS_ERROR_INVALID_ARGS, "Unit is not of type .service");
/* If it would be dropped at startup time, return an error. The context should always be available, but
* there's an assert in exec_needs_mount_namespace, so double-check just in case. */
c = unit_get_exec_context(u);
if (!c)
return sd_bus_error_setf(error, SD_BUS_ERROR_INVALID_ARGS, "Cannot access unit execution context");
if (path_startswith_strv(dest, c->inaccessible_paths))
return sd_bus_error_setf(error, SD_BUS_ERROR_INVALID_ARGS, "%s is not accessible to this unit", dest);
/* Ensure that the unit was started in a private mount namespace */
if (!exec_needs_mount_namespace(c, NULL, unit_get_exec_runtime(u)))
return sd_bus_error_setf(error, SD_BUS_ERROR_INVALID_ARGS, "Unit not running in private mount namespace, cannot activate bind mount");
unit_pid = unit_main_pid(u);
if (unit_pid == 0 || !UNIT_IS_ACTIVE_OR_RELOADING(unit_active_state(u)))
return sd_bus_error_setf(error, SD_BUS_ERROR_INVALID_ARGS, "Unit is not running");
propagate_directory = strjoina("/run/systemd/propagate/", u->id);
r = bind_mount_in_namespace(unit_pid,
propagate_directory,
"/run/systemd/incoming/",
src, dest, read_only, make_file_or_directory);
if (r < 0)
return sd_bus_error_set_errnof(error, r, "Failed to mount %s on %s in unit's namespace: %m", src, dest);
return sd_bus_reply_method_return(message, NULL);
}
const sd_bus_vtable bus_service_vtable[] = {
SD_BUS_VTABLE_START(0),
SD_BUS_PROPERTY("Type", "s", property_get_type, offsetof(Service, type), SD_BUS_VTABLE_PROPERTY_CONST),
@ -146,6 +223,16 @@ const sd_bus_vtable bus_service_vtable[] = {
BUS_EXEC_COMMAND_LIST_VTABLE("ExecStopPost", offsetof(Service, exec_command[SERVICE_EXEC_STOP_POST]), SD_BUS_VTABLE_PROPERTY_EMITS_INVALIDATION),
BUS_EXEC_EX_COMMAND_LIST_VTABLE("ExecStopPostEx", offsetof(Service, exec_command[SERVICE_EXEC_STOP_POST]), SD_BUS_VTABLE_PROPERTY_EMITS_INVALIDATION),
SD_BUS_METHOD_WITH_NAMES("BindMount",
"ssbb",
SD_BUS_PARAM(source)
SD_BUS_PARAM(destination)
SD_BUS_PARAM(read_only)
SD_BUS_PARAM(mkdir),
NULL,,
bus_service_method_bind_mount,
SD_BUS_VTABLE_UNPRIVILEGED),
/* The following four are obsolete, and thus marked hidden here. They moved into the Unit interface */
SD_BUS_PROPERTY("StartLimitInterval", "t", bus_property_get_usec, offsetof(Unit, start_ratelimit.interval), SD_BUS_VTABLE_PROPERTY_CONST|SD_BUS_VTABLE_HIDDEN),
SD_BUS_PROPERTY("StartLimitBurst", "u", bus_property_get_unsigned, offsetof(Unit, start_ratelimit.burst), SD_BUS_VTABLE_PROPERTY_CONST|SD_BUS_VTABLE_HIDDEN),

1
src/core/dbus-service.h
View file

@ -9,4 +9,5 @@
extern const sd_bus_vtable bus_service_vtable[];
int bus_service_set_property(Unit *u, const char *name, sd_bus_message *i, UnitWriteFlags flags, sd_bus_error *error);
int bus_service_method_bind_mount(sd_bus_message *message, void *userdata, sd_bus_error *error);
int bus_service_commit_properties(Unit *u);

32
src/core/dbus-unit.c
View file

@ -323,38 +323,6 @@ static int property_get_load_error(
return sd_bus_message_append(reply, "(ss)", NULL, NULL);
}
static int bus_verify_manage_units_async_full(
Unit *u,
const char *verb,
int capability,
const char *polkit_message,
bool interactive,
sd_bus_message *call,
sd_bus_error *error) {
const char *details[9] = {
"unit", u->id,
"verb", verb,
};
if (polkit_message) {
details[4] = "polkit.message";
details[5] = polkit_message;
details[6] = "polkit.gettext_domain";
details[7] = GETTEXT_PACKAGE;
}
return bus_verify_polkit_async(
call,
capability,
"org.freedesktop.systemd1.manage-units",
details,
interactive,
UID_INVALID,
&u->manager->polkit_registry,
error);
}
static const char *const polkit_message_for_job[_JOB_TYPE_MAX] = {
[JOB_START] = N_("Authentication is required to start '$(unit)'."),
[JOB_STOP] = N_("Authentication is required to stop '$(unit)'."),

33
src/core/dbus-util.c
View file

@ -1,5 +1,6 @@
/* SPDX-License-Identifier: LGPL-2.1-or-later */
#include "bus-polkit.h"
#include "bus-util.h"
#include "dbus-util.h"
#include "parse-util.h"
@ -153,3 +154,35 @@ int bus_set_transient_usec_internal(
return 1;
}
int bus_verify_manage_units_async_full(
Unit *u,
const char *verb,
int capability,
const char *polkit_message,
bool interactive,
sd_bus_message *call,
sd_bus_error *error) {
const char *details[9] = {
"unit", u->id,
"verb", verb,
};
if (polkit_message) {
details[4] = "polkit.message";
details[5] = polkit_message;
details[6] = "polkit.gettext_domain";
details[7] = GETTEXT_PACKAGE;
}
return bus_verify_polkit_async(
call,
capability,
"org.freedesktop.systemd1.manage-units",
details,
interactive,
UID_INVALID,
&u->manager->polkit_registry,
error);
}

1
src/core/dbus-util.h
View file

@ -248,3 +248,4 @@ static inline int bus_set_transient_usec(Unit *u, const char *name, usec_t *p, s
static inline int bus_set_transient_usec_fix_0(Unit *u, const char *name, usec_t *p, sd_bus_message *message, UnitWriteFlags flags, sd_bus_error *error) {
return bus_set_transient_usec_internal(u, name, p, true, message, flags, error);
}
int bus_verify_manage_units_async_full(Unit *u, const char *verb, int capability, const char *polkit_message, bool interactive, sd_bus_message *call, sd_bus_error *error);

18
src/core/execute.c
View file

@ -1987,13 +1987,12 @@ static int build_pass_environment(const ExecContext *c, char ***ret) {
return 0;
}
static bool exec_needs_mount_namespace(
bool exec_needs_mount_namespace(
const ExecContext *context,
const ExecParameters *params,
const ExecRuntime *runtime) {
assert(context);
assert(params);
if (context->root_image)
return true;
@ -2035,7 +2034,7 @@ static bool exec_needs_mount_namespace(
return true;
for (ExecDirectoryType t = 0; t < _EXEC_DIRECTORY_TYPE_MAX; t++) {
if (!params->prefix[t])
if (params && !params->prefix[t])
continue;
if (!strv_isempty(context->directories[t].paths))
@ -3115,7 +3114,7 @@ static int apply_mount_namespace(
_cleanup_strv_free_ char **empty_directories = NULL;
const char *tmp_dir = NULL, *var_tmp_dir = NULL;
const char *root_dir = NULL, *root_image = NULL;
_cleanup_free_ char *creds_path = NULL;
_cleanup_free_ char *creds_path = NULL, *incoming_dir = NULL, *propagate_dir = NULL;
NamespaceInfo ns_info;
bool needs_sandboxing;
BindMount *bind_mounts = NULL;
@ -3192,6 +3191,15 @@ static int apply_mount_namespace(
}
}
if (MANAGER_IS_SYSTEM(u->manager)) {
propagate_dir = path_join("/run/systemd/propagate/", u->id);
if (!propagate_dir)
return -ENOMEM;
incoming_dir = strdup("/run/systemd/incoming");
if (!incoming_dir)
return -ENOMEM;
}
r = setup_namespace(root_dir, root_image, context->root_image_options,
&ns_info, context->read_write_paths,
needs_sandboxing ? context->read_only_paths : NULL,
@ -3211,6 +3219,8 @@ static int apply_mount_namespace(
context->root_hash, context->root_hash_size, context->root_hash_path,
context->root_hash_sig, context->root_hash_sig_size, context->root_hash_sig_path,
context->root_verity,
propagate_dir,
incoming_dir,
DISSECT_IMAGE_DISCARD_ON_LOOP|DISSECT_IMAGE_RELAX_VAR_CHECK|DISSECT_IMAGE_FSCK,
error_path);

2
src/core/execute.h
View file

@ -471,3 +471,5 @@ ExecDirectoryType exec_directory_type_from_string(const char *s) _pure_;
const char* exec_resource_type_to_string(ExecDirectoryType i) _const_;
ExecDirectoryType exec_resource_type_from_string(const char *s) _pure_;
bool exec_needs_mount_namespace(const ExecContext *context, const ExecParameters *params, const ExecRuntime *runtime);

37
src/core/namespace.c
View file

@ -1301,7 +1301,8 @@ static size_t namespace_calculate_mounts(
const char* tmp_dir,
const char* var_tmp_dir,
const char *creds_path,
const char* log_namespace) {
const char* log_namespace,
bool setup_propagate) {
size_t protect_home_cnt;
size_t protect_system_cnt =
@ -1328,6 +1329,7 @@ static size_t namespace_calculate_mounts(
n_bind_mounts +
n_mount_images +
n_temporary_filesystems +
(setup_propagate ? 1 : 0) + /* /run/systemd/incoming */
ns_info->private_dev +
(ns_info->protect_kernel_tunables ? ELEMENTSOF(protect_kernel_tunables_table) : 0) +
(ns_info->protect_kernel_modules ? ELEMENTSOF(protect_kernel_modules_table) : 0) +
@ -1487,6 +1489,8 @@ int setup_namespace(
size_t root_hash_sig_size,
const char *root_hash_sig_path,
const char *verity_data_path,
const char *propagate_dir,
const char *incoming_dir,
DissectImageFlags dissect_image_flags,
char **error_path) {
@ -1495,13 +1499,16 @@ int setup_namespace(
_cleanup_(dissected_image_unrefp) DissectedImage *dissected_image = NULL;
_cleanup_(verity_settings_done) VeritySettings verity = VERITY_SETTINGS_DEFAULT;
MountEntry *m = NULL, *mounts = NULL;
bool require_prefix = false;
bool require_prefix = false, setup_propagate = false;
const char *root;
size_t n_mounts;
int r;
assert(ns_info);
if (!isempty(propagate_dir) && !isempty(incoming_dir))
setup_propagate = true;
if (mount_flags == 0)
mount_flags = MS_SHARED;
@ -1585,7 +1592,8 @@ int setup_namespace(
n_mount_images,
tmp_dir, var_tmp_dir,
creds_path,
log_namespace);
log_namespace,
setup_propagate);
if (n_mounts > 0) {
m = mounts = new0(MountEntry, n_mounts);
@ -1754,6 +1762,15 @@ int setup_namespace(
};
}
/* Will be used to add bind mounts at runtime */
if (setup_propagate)
*(m++) = (MountEntry) {
.source_const = propagate_dir,
.path_const = incoming_dir,
.mode = BIND_MOUNT,
.read_only = true,
};
assert(mounts + n_mounts == m);
/* Prepend the root directory where that's necessary */
@ -1778,6 +1795,10 @@ int setup_namespace(
goto finish;
}
/* Create the source directory to allow runtime propagation of mounts */
if (setup_propagate)
(void) mkdir_p(propagate_dir, 0600);
/* Remount / as SLAVE so that nothing now mounted in the namespace
* shows up in the parent */
if (mount(NULL, "/", NULL, MS_SLAVE|MS_REC, NULL) < 0) {
@ -1919,6 +1940,16 @@ int setup_namespace(
goto finish;
}
/* bind_mount_in_namespace() will MS_MOVE into that directory, and that's only
* supported for non-shared mounts. This needs to happen after remounting / or it will fail. */
if (setup_propagate) {
r = mount(NULL, incoming_dir, NULL, MS_SLAVE, NULL);
if (r < 0) {
log_error_errno(r, "Failed to remount %s with MS_SLAVE: %m", incoming_dir);
goto finish;
}
}
r = 0;
finish:

2
src/core/namespace.h
View file

@ -127,6 +127,8 @@ int setup_namespace(
size_t root_hash_sig_size,
const char *root_hash_sig_path,
const char *root_verity,
const char *propagate_dir,
const char *incoming_dir,
DissectImageFlags dissected_image_flags,
char **error_path);

8
src/core/org.freedesktop.systemd1.conf
View file

@ -222,6 +222,10 @@
send_interface="org.freedesktop.systemd1.Manager"
send_member="ReloadOrTryRestartUnit"/>
<allow send_destination="org.freedesktop.systemd1"
send_interface="org.freedesktop.systemd1.Manager"
send_member="BindMountUnit"/>
<allow send_destination="org.freedesktop.systemd1"
send_interface="org.freedesktop.systemd1.Manager"
send_member="KillUnit"/>
@ -392,6 +396,10 @@
send_interface="org.freedesktop.systemd1.Service"
send_member="AttachProcesses"/>
<allow send_destination="org.freedesktop.systemd1"
send_interface="org.freedesktop.systemd1.Service"
send_member="BindMount"/>
<!-- Managed via polkit or other criteria: org.freedesktop.systemd1.Scope interface -->
<allow send_destination="org.freedesktop.systemd1"

41
src/systemctl/systemctl-mount.c Normal file
View file

@ -0,0 +1,41 @@
/* SPDX-License-Identifier: LGPL-2.1+ */
#include "bus-error.h"
#include "bus-locator.h"
#include "systemctl-mount.h"
#include "systemctl-util.h"
#include "systemctl.h"
int mount_bind(int argc, char *argv[], void *userdata) {
_cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
_cleanup_free_ char *n = NULL;
sd_bus *bus;
int r;
r = acquire_bus(BUS_MANAGER, &bus);
if (r < 0)
return r;
polkit_agent_open_maybe();
r = unit_name_mangle(argv[1], arg_quiet ? 0 : UNIT_NAME_MANGLE_WARN, &n);
if (r < 0)
return log_error_errno(r, "Failed to mangle unit name: %m");
r = bus_call_method(
bus,
bus_systemd_mgr,
"BindMountUnit",
&error,
NULL,
"sssbb",
n,
argv[2],
argv[3],
arg_read_only,
arg_mkdir);
if (r < 0)
return log_error_errno(r, "Failed to bind mount: %s", bus_error_message(&error, r));
return 0;
}

4
src/systemctl/systemctl-mount.h Normal file
View file

@ -0,0 +1,4 @@
/* SPDX-License-Identifier: LGPL-2.1+ */
#pragma once
int mount_bind(int argc, char *argv[], void *userdata);

20
src/systemctl/systemctl.c
View file

@ -38,6 +38,7 @@
#include "systemctl-list-units.h"
#include "systemctl-log-setting.h"
#include "systemctl-logind.h"
#include "systemctl-mount.h"
#include "systemctl-preset-all.h"
#include "systemctl-reset-failed.h"
#include "systemctl-service-watchdogs.h"
@ -105,6 +106,8 @@ bool arg_jobs_before = false;
bool arg_jobs_after = false;
char **arg_clean_what = NULL;
TimestampStyle arg_timestamp_style = TIMESTAMP_PRETTY;
bool arg_read_only = false;
bool arg_mkdir = false;
STATIC_DESTRUCTOR_REGISTER(arg_wall, strv_freep);
STATIC_DESTRUCTOR_REGISTER(arg_root, freep);
@ -157,6 +160,8 @@ static int systemctl_help(void) {
" freeze PATTERN... Freeze execution of unit processes\n"
" thaw PATTERN... Resume execution of a frozen unit\n"
" set-property UNIT PROPERTY=VALUE... Sets one or more properties of a unit\n"
" bind UNIT PATH [PATH] Bind-mount a path from the host into a\n"
" unit's namespace\n"
" service-log-level SERVICE [LEVEL] Get/set logging threshold for service\n"
" service-log-target SERVICE [TARGET] Get/set logging target for service\n"
" reset-failed [PATTERN...] Reset failed state for all, one, or more\n"
@ -286,6 +291,8 @@ static int systemctl_help(void) {
" 'us': 'Day YYYY-MM-DD HH:MM:SS.UUUUUU TZ\n"
" 'utc': 'Day YYYY-MM-DD HH:MM:SS UTC\n"
" 'us+utc': 'Day YYYY-MM-DD HH:MM:SS.UUUUUU UTC\n"
" --read-only Create read-only bind mount\n"
" --mkdir Create directory before bind-mounting, if missing\n"
"\nSee the %2$s for details.\n"
, program_invocation_short_name
, link
@ -401,6 +408,8 @@ static int systemctl_parse_argv(int argc, char *argv[]) {
ARG_WHAT,
ARG_REBOOT_ARG,
ARG_TIMESTAMP_STYLE,
ARG_READ_ONLY,
ARG_MKDIR,
};
static const struct option options[] = {
@ -457,6 +466,8 @@ static int systemctl_parse_argv(int argc, char *argv[]) {
{ "what", required_argument, NULL, ARG_WHAT },
{ "reboot-argument", required_argument, NULL, ARG_REBOOT_ARG },
{ "timestamp", required_argument, NULL, ARG_TIMESTAMP_STYLE },
{ "read-only", no_argument, NULL, ARG_READ_ONLY },
{ "mkdir", no_argument, NULL, ARG_MKDIR },
{}
};
@ -878,6 +889,14 @@ static int systemctl_parse_argv(int argc, char *argv[]) {
break;
case ARG_READ_ONLY:
arg_read_only = true;
break;
case ARG_MKDIR:
arg_mkdir = true;
break;
case '.':
/* Output an error mimicking getopt, and print a hint afterwards */
log_error("%s: invalid option -- '.'", program_invocation_name);
@ -1045,6 +1064,7 @@ static int systemctl_main(int argc, char *argv[]) {
{ "add-wants", 3, VERB_ANY, 0, add_dependency },
{ "add-requires", 3, VERB_ANY, 0, add_dependency },
{ "edit", 2, VERB_ANY, VERB_ONLINE_ONLY, edit },
{ "bind", 3, 4, VERB_ONLINE_ONLY, mount_bind },
{}
};

2
src/systemctl/systemctl.h
View file

@ -90,3 +90,5 @@ extern bool arg_jobs_before;
extern bool arg_jobs_after;
extern char **arg_clean_what;
extern TimestampStyle arg_timestamp_style;
extern bool arg_read_only;
extern bool arg_mkdir;

2
src/test/test-namespace.c
View file

@ -172,6 +172,8 @@ static void test_protect_kernel_logs(void) {
0,
NULL,
NULL,
NULL,
NULL,
0,
NULL);
assert_se(r == 0);

2
src/test/test-ns.c
View file

@ -87,6 +87,8 @@ int main(int argc, char *argv[]) {
0,
NULL,
NULL,
NULL,
NULL,
0,
NULL);
if (r < 0) {

1
test/TEST-57-RUNTIME-BIND-PATHS/Makefile Symbolic link
View file

@ -0,0 +1 @@
../TEST-01-BASIC/Makefile

7
test/TEST-57-RUNTIME-BIND-PATHS/test.sh Executable file
View file

@ -0,0 +1,7 @@
#!/usr/bin/env bash
set -e
TEST_DESCRIPTION="test adding new BindPaths while unit is already running"
. $TEST_BASE_DIR/test-functions
do_test "$@" 57

12
test/units/testsuite-57-namespaced.service Normal file
View file

@ -0,0 +1,12 @@
[Service]
RuntimeMaxSec=300
# Adding a new mounts at runtime works if the unit is in the active state,
# so use Type=notify to make sure there's no race condition in the test
Type=notify
RemainAfterExit=yes
MountAPIVFS=yes
PrivateTmp=yes
BindPaths=/run/testservice-57-fixed:/tmp/testfile_fixed
InaccessiblePaths=/run/inaccessible
ExecStartPre=grep -q -F MARKER_FIXED /tmp/testfile_fixed
ExecStart=/bin/sh -c 'systemd-notify --ready; while ! grep -q -F MARKER_RUNTIME /tmp/testfile_runtime; do sleep 0.1; done; test ! -f /run/inaccessible/testfile_fixed'

5
test/units/testsuite-57-non-namespaced.service Normal file
View file

@ -0,0 +1,5 @@
[Service]
RuntimeMaxSec=10
Type=notify
RemainAfterExit=yes
ExecStart=/bin/sh -c 'systemd-notify --ready; while ! grep -q -F MARKER_RUNTIME /tmp/testfile_runtime; do sleep 0.1; done; exit 0'

7
test/units/testsuite-57.service Normal file
View file

@ -0,0 +1,7 @@
[Unit]
Description=TEST-57-RUNTIME-BIND-PATHS
[Service]
ExecStartPre=rm -f /failed /testok
ExecStart=/usr/lib/systemd/tests/testdata/units/%N.sh
Type=oneshot

43
test/units/testsuite-57.sh Executable file
View file

@ -0,0 +1,43 @@
#!/usr/bin/env bash
set -ex
echo "MARKER_FIXED" > /run/testservice-57-fixed
mkdir -p /run/inaccessible
systemctl start testsuite-57-namespaced.service
# Ensure that inaccessible paths aren't bypassed by the runtime setup
set +e
systemctl bind --mkdir testsuite-57-namespaced.service /run/testservice-57-fixed /run/inaccessible/testfile_fixed && exit 1
set -e
echo "MARKER_RUNTIME" > /run/testservice-57-runtime
systemctl bind --mkdir testsuite-57-namespaced.service /run/testservice-57-runtime /tmp/testfile_runtime
while systemctl show -P SubState testsuite-57-namespaced.service | grep -q running
do
sleep 0.1
done
systemctl is-active testsuite-57-namespaced.service
# Now test that systemctl bind fails when attempted on a non-namespaced unit
systemctl start testsuite-57-non-namespaced.service
set +e
systemctl bind --mkdir testsuite-57-non-namespaced.service /run/testservice-57-runtime /tmp/testfile_runtime && exit 1
set -e
while systemctl show -P SubState testsuite-57-non-namespaced.service | grep -q running
do
sleep 0.1
done
set +e
systemctl is-active testsuite-57-non-namespaced.service && exit 1
set -e
echo OK > /testok
exit 0