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-rw-r--r--man/machinectl.xml44
-rw-r--r--src/machine/machinectl.c302
-rw-r--r--src/nspawn/nspawn.c31
3 files changed, 339 insertions, 38 deletions
diff --git a/man/machinectl.xml b/man/machinectl.xml
index 2f2e2571f5..9d8a94aab4 100644
--- a/man/machinectl.xml
+++ b/man/machinectl.xml
@@ -146,6 +146,25 @@
footer.</para></listitem>
</varlistentry>
+ <varlistentry>
+ <term><option>--mkdir</option></term>
+
+ <listitem><para>When used with
+ <command>bind</command> creates the
+ destination directory before applying
+ the bind mount.</para></listitem>
+ </varlistentry>
+
+
+ <varlistentry>
+ <term><option>--read-only</option></term>
+
+ <listitem><para>When used with
+ <command>bind</command> applies 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" />
@@ -270,6 +289,31 @@
instance.</para></listitem>
</varlistentry>
+ <varlistentry>
+ <term><command>bind</command> <replaceable>ID</replaceable> <replaceable>DIRECTORY</replaceable> [<replaceable>DIRECTORY</replaceable>]</term>
+
+ <listitem><para>Bind mounts a
+ directory from the host into the
+ specified container. The first
+ directory argument is the source
+ directory on the host, the second
+ directory argument the source
+ directory on the host. When the latter
+ is omitted the destination path in the
+ container 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
+ <citerefentry><refentrytitle>systemd-nspawn</refentrytitle><manvolnum>1</manvolnum></citerefentry>
+ containers.</para></listitem>
+ </varlistentry>
+
</variablelist>
</refsect1>
diff --git a/src/machine/machinectl.c b/src/machine/machinectl.c
index f604263d8f..2571fc0c71 100644
--- a/src/machine/machinectl.c
+++ b/src/machine/machinectl.c
@@ -30,6 +30,7 @@
#include <netinet/in.h>
#include <arpa/inet.h>
#include <net/if.h>
+#include <sys/mount.h>
#include "sd-bus.h"
#include "log.h"
@@ -45,6 +46,8 @@
#include "cgroup-util.h"
#include "ptyfwd.h"
#include "event-util.h"
+#include "path-util.h"
+#include "mkdir.h"
static char **arg_property = NULL;
static bool arg_all = false;
@@ -55,6 +58,8 @@ static const char *arg_kill_who = NULL;
static int arg_signal = SIGTERM;
static BusTransport arg_transport = BUS_TRANSPORT_LOCAL;
static char *arg_host = NULL;
+static bool arg_read_only = false;
+static bool arg_mkdir = false;
static void pager_open_if_enabled(void) {
@@ -572,6 +577,241 @@ static int terminate_machine(sd_bus *bus, char **args, unsigned n) {
return 0;
}
+static int machine_get_leader(sd_bus *bus, const char *name, pid_t *ret) {
+ _cleanup_bus_error_free_ sd_bus_error error = SD_BUS_ERROR_NULL;
+ _cleanup_bus_message_unref_ sd_bus_message *reply = NULL, *reply2 = NULL;
+ const char *object;
+ uint32_t leader;
+ int r;
+
+ assert(bus);
+ assert(name);
+ assert(ret);
+
+ r = sd_bus_call_method(
+ bus,
+ "org.freedesktop.machine1",
+ "/org/freedesktop/machine1",
+ "org.freedesktop.machine1.Manager",
+ "GetMachine",
+ &error,
+ &reply,
+ "s", name);
+ if (r < 0) {
+ log_error("Could not get path to machine: %s", bus_error_message(&error, -r));
+ return r;
+ }
+
+ r = sd_bus_message_read(reply, "o", &object);
+ if (r < 0)
+ return bus_log_parse_error(r);
+
+ r = sd_bus_get_property(
+ bus,
+ "org.freedesktop.machine1",
+ object,
+ "org.freedesktop.machine1.Machine",
+ "Leader",
+ &error,
+ &reply2,
+ "u");
+ if (r < 0)
+ return log_error_errno(r, "Failed to retrieve PID of leader: %m");
+
+ r = sd_bus_message_read(reply2, "u", &leader);
+ if (r < 0)
+ return bus_log_parse_error(r);
+
+ *ret = leader;
+ return 0;
+}
+
+static int bind_mount(sd_bus *bus, char **args, unsigned n) {
+ char mount_slave[] = "/tmp/propagate.XXXXXX", *mount_tmp, *mount_outside, *p;
+ pid_t child, leader;
+ const char *dest;
+ siginfo_t si;
+ bool mount_slave_created = false, mount_slave_mounted = false,
+ mount_tmp_created = false, mount_tmp_mounted = false,
+ mount_outside_created = false, mount_outside_mounted = false;
+ int r;
+
+ /* One day, when bind mounting /proc/self/fd/n works across
+ * namespace boundaries we should rework this logic to make
+ * use of it... */
+
+ if (n > 4) {
+ log_error("Too many arguments.");
+ return -EINVAL;
+ }
+
+ dest = args[3] ?: args[2];
+ if (!path_is_absolute(dest)) {
+ log_error("Destination path not absolute.");
+ return -EINVAL;
+ }
+
+ p = strappenda("/run/systemd/nspawn/propagate/", args[1], "/");
+ if (access(p, F_OK) < 0) {
+ log_error("Container does not allow propagation of mount points.");
+ return -ENOTSUP;
+ }
+
+ r = machine_get_leader(bus, args[1], &leader);
+ if (r < 0)
+ return r;
+
+ /* Our goal is to install a new bind mount into the container,
+ possibly read-only. This is irritatingly complex
+ unfortunately, currently.
+
+ First, we start by creating a private playground in /tmp,
+ that we can mount MS_SLAVE. (Which is necessary, since
+ MS_MOUNT cannot be applied to mounts with MS_SHARED parent
+ mounts.) */
+
+ if (!mkdtemp(mount_slave))
+ return log_error_errno(errno, "Failed to create playground: %m");
+
+ mount_slave_created = true;
+
+ if (mount(mount_slave, mount_slave, NULL, MS_BIND, NULL) < 0) {
+ r = log_error_errno(errno, "Failed to make bind mount: %m");
+ goto finish;
+ }
+
+ mount_slave_mounted = true;
+
+ if (mount(NULL, mount_slave, NULL, MS_SLAVE, NULL) < 0) {
+ r = log_error_errno(errno, "Failed to remount slave: %m");
+ goto finish;
+ }
+
+ /* Second, we mount the source directory to a directory inside
+ of our MS_SLAVE playground. */
+ mount_tmp = strappenda(mount_slave, "/mount");
+ if (mkdir(mount_tmp, 0700) < 0) {
+ r = log_error_errno(errno, "Failed to create temporary mount: %m");
+ goto finish;
+ }
+
+ mount_tmp_created = true;
+
+ if (mount(args[2], mount_tmp, NULL, MS_BIND, NULL) < 0) {
+ r = log_error_errno(errno, "Failed to overmount: %m");
+ goto finish;
+ }
+
+ mount_tmp_mounted = true;
+
+ /* Third, we remount the new bind mount read-only if requested. */
+ if (arg_read_only)
+ if (mount(NULL, mount_tmp, NULL, MS_BIND|MS_REMOUNT|MS_RDONLY, NULL) < 0) {
+ r = log_error_errno(errno, "Failed to mark read-only: %m");
+ goto finish;
+ }
+
+ /* Fourth, we move the new bind mount into the propagation
+ * directory. This way it will appear there read-only
+ * right-away. */
+
+ mount_outside = strappenda("/run/systemd/nspawn/propagate/", args[1], "/XXXXXX");
+ if (!mkdtemp(mount_outside)) {
+ r = log_error_errno(errno, "Cannot create propagation directory: %m");
+ goto finish;
+ }
+
+ mount_outside_created = true;
+
+ if (mount(mount_tmp, mount_outside, NULL, MS_MOVE, NULL) < 0) {
+ r = log_error_errno(errno, "Failed to move: %m");
+ goto finish;
+ }
+
+ mount_outside_mounted = true;
+ mount_tmp_mounted = false;
+
+ (void) rmdir(mount_tmp);
+ mount_tmp_created = false;
+
+ (void) umount(mount_slave);
+ mount_slave_mounted = false;
+
+ (void) rmdir(mount_slave);
+ mount_slave_created = false;
+
+ child = fork();
+ if (child < 0) {
+ r = log_error_errno(errno, "Failed to fork(): %m");
+ goto finish;
+ }
+
+ if (child == 0) {
+ const char *mount_inside;
+ int mntfd;
+ const char *q;
+
+ q = procfs_file_alloca(leader, "ns/mnt");
+ mntfd = open(q, O_RDONLY|O_NOCTTY|O_CLOEXEC);
+ if (mntfd < 0) {
+ log_error_errno(errno, "Failed to open mount namespace of leader: %m");
+ _exit(EXIT_FAILURE);
+ }
+
+ if (setns(mntfd, CLONE_NEWNS) < 0) {
+ log_error_errno(errno, "Failed to join namespace of leader: %m");
+ _exit(EXIT_FAILURE);
+ }
+
+ if (arg_mkdir)
+ mkdir_p(dest, 0755);
+
+ /* Fifth, move the mount to the right place inside */
+ mount_inside = strappenda("/run/systemd/nspawn/incoming/", basename(mount_outside));
+ if (mount(mount_inside, dest, NULL, MS_MOVE, NULL) < 0) {
+ log_error_errno(errno, "Failed to mount: %m");
+ _exit(EXIT_FAILURE);
+ }
+
+ _exit(EXIT_SUCCESS);
+ }
+
+ r = wait_for_terminate(child, &si);
+ if (r < 0) {
+ log_error_errno(r, "Failed to wait for client: %m");
+ goto finish;
+ }
+ if (si.si_code != CLD_EXITED) {
+ log_error("Client died abnormally.");
+ r = -EIO;
+ goto finish;
+ }
+ if (si.si_status != EXIT_SUCCESS) {
+ r = -EIO;
+ goto finish;
+ }
+
+ r = 0;
+
+finish:
+ if (mount_outside_mounted)
+ umount(mount_outside);
+ if (mount_outside_created)
+ rmdir(mount_outside);
+
+ if (mount_tmp_mounted)
+ umount(mount_tmp);
+ if (mount_tmp_created)
+ umount(mount_tmp);
+
+ if (mount_slave_mounted)
+ umount(mount_slave);
+ if (mount_slave_created)
+ umount(mount_slave);
+
+ return r;
+}
+
static int openpt_in_namespace(pid_t pid, int flags) {
_cleanup_close_pair_ int pair[2] = { -1, -1 };
_cleanup_close_ int pidnsfd = -1, mntnsfd = -1, rootfd = -1;
@@ -658,15 +898,15 @@ static int openpt_in_namespace(pid_t pid, int flags) {
}
static int login_machine(sd_bus *bus, char **args, unsigned n) {
- _cleanup_bus_message_unref_ sd_bus_message *reply = NULL, *reply2 = NULL, *reply3 = NULL;
_cleanup_bus_error_free_ sd_bus_error error = SD_BUS_ERROR_NULL;
+ _cleanup_bus_message_unref_ sd_bus_message *reply = NULL;
_cleanup_bus_close_unref_ sd_bus *container_bus = NULL;
_cleanup_(pty_forward_freep) PTYForward *forward = NULL;
_cleanup_event_unref_ sd_event *event = NULL;
_cleanup_close_ int master = -1;
_cleanup_free_ char *getty = NULL;
- const char *path, *pty, *p;
- uint32_t leader;
+ const char *pty, *p;
+ pid_t leader;
sigset_t mask;
int r, ret = 0;
@@ -686,39 +926,9 @@ static int login_machine(sd_bus *bus, char **args, unsigned n) {
if (r < 0)
return log_error_errno(r, "Failed to attach bus to event loop: %m");
- r = sd_bus_call_method(
- bus,
- "org.freedesktop.machine1",
- "/org/freedesktop/machine1",
- "org.freedesktop.machine1.Manager",
- "GetMachine",
- &error,
- &reply,
- "s", args[1]);
- if (r < 0) {
- log_error("Could not get path to machine: %s", bus_error_message(&error, -r));
- return r;
- }
-
- r = sd_bus_message_read(reply, "o", &path);
- if (r < 0)
- return bus_log_parse_error(r);
-
- r = sd_bus_get_property(
- bus,
- "org.freedesktop.machine1",
- path,
- "org.freedesktop.machine1.Machine",
- "Leader",
- &error,
- &reply2,
- "u");
- if (r < 0)
- return log_error_errno(r, "Failed to retrieve PID of leader: %m");
-
- r = sd_bus_message_read(reply2, "u", &leader);
+ r = machine_get_leader(bus, args[1], &leader);
if (r < 0)
- return bus_log_parse_error(r);
+ return r;
master = openpt_in_namespace(leader, O_RDWR|O_NOCTTY|O_CLOEXEC|O_NDELAY);
if (master < 0)
@@ -750,7 +960,7 @@ static int login_machine(sd_bus *bus, char **args, unsigned n) {
"/org/freedesktop/systemd1",
"org.freedesktop.systemd1.Manager",
"StartUnit",
- &error, &reply3,
+ &error, &reply,
"ss", getty, "replace");
if (r < 0) {
log_error("Failed to start getty service: %s", bus_error_message(&error, r));
@@ -799,7 +1009,9 @@ static void help(void) {
" -a --all Show all properties, including empty ones\n"
" -l --full Do not ellipsize output\n"
" --kill-who=WHO Who to send signal to\n"
- " -s --signal=SIGNAL Which signal to send\n\n"
+ " -s --signal=SIGNAL Which signal to send\n"
+ " --read-only Create read-only bind mount\n"
+ " --mkdir Create directory before bind mounting, if missing\n\n"
"Commands:\n"
" list List running VMs and containers\n"
" status NAME... Show VM/container status\n"
@@ -808,7 +1020,8 @@ static void help(void) {
" poweroff NAME... Power off one or more containers\n"
" reboot NAME... Reboot one or more containers\n"
" kill NAME... Send signal to processes of a VM/container\n"
- " terminate NAME... Terminate one or more VMs/containers\n",
+ " terminate NAME... Terminate one or more VMs/containers\n"
+ " bind NAME PATH [PATH] Bind mount a path from the host into a container\n",
program_invocation_short_name);
}
@@ -819,6 +1032,8 @@ static int parse_argv(int argc, char *argv[]) {
ARG_NO_PAGER,
ARG_NO_LEGEND,
ARG_KILL_WHO,
+ ARG_READ_ONLY,
+ ARG_MKDIR,
};
static const struct option options[] = {
@@ -833,6 +1048,8 @@ static int parse_argv(int argc, char *argv[]) {
{ "signal", required_argument, NULL, 's' },
{ "host", required_argument, NULL, 'H' },
{ "machine", required_argument, NULL, 'M' },
+ { "read-only", no_argument, NULL, ARG_READ_ONLY },
+ { "mkdir", no_argument, NULL, ARG_MKDIR },
{}
};
@@ -903,6 +1120,14 @@ static int parse_argv(int argc, char *argv[]) {
arg_host = optarg;
break;
+ case ARG_READ_ONLY:
+ arg_read_only = true;
+ break;
+
+ case ARG_MKDIR:
+ arg_mkdir = true;
+ break;
+
case '?':
return -EINVAL;
@@ -933,6 +1158,7 @@ static int machinectl_main(sd_bus *bus, int argc, char *argv[]) {
{ "poweroff", MORE, 2, poweroff_machine },
{ "kill", MORE, 2, kill_machine },
{ "login", MORE, 2, login_machine },
+ { "bind", MORE, 3, bind_mount },
};
int left;
diff --git a/src/nspawn/nspawn.c b/src/nspawn/nspawn.c
index a13c1fcd24..72f7d66782 100644
--- a/src/nspawn/nspawn.c
+++ b/src/nspawn/nspawn.c
@@ -2082,6 +2082,27 @@ finish:
}
+static int setup_propagate(const char *root) {
+ const char *p, *q;
+
+ (void) mkdir_p("/run/systemd/nspawn/", 0755);
+ (void) mkdir_p("/run/systemd/nspawn/propagate", 0600);
+ p = strappenda("/run/systemd/nspawn/propagate/", arg_machine);
+ (void) mkdir_p(p, 0600);
+
+ q = strappenda(root, "/run/systemd/nspawn/incoming");
+ mkdir_parents(q, 0755);
+ mkdir_p(q, 0600);
+
+ if (mount(p, q, NULL, MS_BIND, NULL) < 0)
+ return log_error_errno(errno, "Failed to install propagation bind mount.");
+
+ if (mount(NULL, q, NULL, MS_BIND|MS_REMOUNT|MS_RDONLY, NULL) < 0)
+ return log_error_errno(errno, "Failed to make propagation mount read-only");
+
+ return 0;
+}
+
static int setup_image(char **device_path, int *loop_nr) {
struct loop_info64 info = {
.lo_flags = LO_FLAGS_AUTOCLEAR|LO_FLAGS_PARTSCAN
@@ -3260,6 +3281,9 @@ int main(int argc, char *argv[]) {
dev_setup(arg_directory);
+ if (setup_propagate(arg_directory) < 0)
+ _exit(EXIT_FAILURE);
+
if (setup_seccomp() < 0)
_exit(EXIT_FAILURE);
@@ -3571,6 +3595,13 @@ finish:
log_warning_errno(k, "Cannot remove subvolume '%s', ignoring: %m", arg_directory);
}
+ if (arg_machine) {
+ const char *p;
+
+ p = strappenda("/run/systemd/nspawn/propagate", arg_machine);
+ (void) rm_rf(p, false, true, false);
+ }
+
free(arg_directory);
free(arg_template);
free(arg_image);
generated by cgit v1.2.3-54-g00ecf (git 2.45.2) at 2024-07-13 01:37:04 +0000