Adding upstream version 247.3.upstream/247.3upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1135 insertions, 0 deletions

diff --git a/src/core/automount.c b/src/core/automount.c
new file mode 100644
index 0000000..a84cddb
--- /dev/null
+++ b/src/core/automount.c
@@ -0,0 +1,1135 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include <errno.h>
+#include <fcntl.h>
+#include <limits.h>
+#include <linux/auto_dev-ioctl.h>
+#include <linux/auto_fs4.h>
+#include <sys/epoll.h>
+#include <sys/mount.h>
+#include <sys/stat.h>
+#include <unistd.h>
+
+#include "alloc-util.h"
+#include "async.h"
+#include "automount.h"
+#include "bus-error.h"
+#include "bus-util.h"
+#include "dbus-automount.h"
+#include "dbus-unit.h"
+#include "fd-util.h"
+#include "format-util.h"
+#include "io-util.h"
+#include "label.h"
+#include "mkdir.h"
+#include "mount-util.h"
+#include "mount.h"
+#include "mountpoint-util.h"
+#include "parse-util.h"
+#include "path-util.h"
+#include "process-util.h"
+#include "serialize.h"
+#include "special.h"
+#include "stdio-util.h"
+#include "string-table.h"
+#include "string-util.h"
+#include "unit-name.h"
+#include "unit.h"
+
+static const UnitActiveState state_translation_table[_AUTOMOUNT_STATE_MAX] = {
+        [AUTOMOUNT_DEAD] = UNIT_INACTIVE,
+        [AUTOMOUNT_WAITING] = UNIT_ACTIVE,
+        [AUTOMOUNT_RUNNING] = UNIT_ACTIVE,
+        [AUTOMOUNT_FAILED] = UNIT_FAILED
+};
+
+struct expire_data {
+        int dev_autofs_fd;
+        int ioctl_fd;
+};
+
+static void expire_data_free(struct expire_data *data) {
+        if (!data)
+                return;
+
+        safe_close(data->dev_autofs_fd);
+        safe_close(data->ioctl_fd);
+        free(data);
+}
+
+DEFINE_TRIVIAL_CLEANUP_FUNC(struct expire_data*, expire_data_free);
+
+static int open_dev_autofs(Manager *m);
+static int automount_dispatch_io(sd_event_source *s, int fd, uint32_t events, void *userdata);
+static int automount_start_expire(Automount *a);
+static void automount_stop_expire(Automount *a);
+static int automount_send_ready(Automount *a, Set *tokens, int status);
+
+static void automount_init(Unit *u) {
+        Automount *a = AUTOMOUNT(u);
+
+        assert(u);
+        assert(u->load_state == UNIT_STUB);
+
+        a->pipe_fd = -1;
+        a->directory_mode = 0755;
+        UNIT(a)->ignore_on_isolate = true;
+}
+
+static void unmount_autofs(Automount *a) {
+        int r;
+
+        assert(a);
+
+        if (a->pipe_fd < 0)
+                return;
+
+        a->pipe_event_source = sd_event_source_unref(a->pipe_event_source);
+        a->pipe_fd = safe_close(a->pipe_fd);
+
+        /* If we reload/reexecute things we keep the mount point around */
+        if (!IN_SET(UNIT(a)->manager->objective, MANAGER_RELOAD, MANAGER_REEXECUTE)) {
+
+                automount_send_ready(a, a->tokens, -EHOSTDOWN);
+                automount_send_ready(a, a->expire_tokens, -EHOSTDOWN);
+
+                if (a->where) {
+                        r = repeat_unmount(a->where, MNT_DETACH|UMOUNT_NOFOLLOW);
+                        if (r < 0)
+                                log_error_errno(r, "Failed to unmount: %m");
+                }
+        }
+}
+
+static void automount_done(Unit *u) {
+        Automount *a = AUTOMOUNT(u);
+
+        assert(a);
+
+        unmount_autofs(a);
+
+        a->where = mfree(a->where);
+
+        a->tokens = set_free(a->tokens);
+        a->expire_tokens = set_free(a->expire_tokens);
+
+        a->expire_event_source = sd_event_source_unref(a->expire_event_source);
+}
+
+static int automount_add_trigger_dependencies(Automount *a) {
+        Unit *x;
+        int r;
+
+        assert(a);
+
+        r = unit_load_related_unit(UNIT(a), ".mount", &x);
+        if (r < 0)
+                return r;
+
+        return unit_add_two_dependencies(UNIT(a), UNIT_BEFORE, UNIT_TRIGGERS, x, true, UNIT_DEPENDENCY_IMPLICIT);
+}
+
+static int automount_add_mount_dependencies(Automount *a) {
+        _cleanup_free_ char *parent = NULL;
+
+        assert(a);
+
+        parent = dirname_malloc(a->where);
+        if (!parent)
+                return -ENOMEM;
+
+        return unit_require_mounts_for(UNIT(a), parent, UNIT_DEPENDENCY_IMPLICIT);
+}
+
+static int automount_add_default_dependencies(Automount *a) {
+        int r;
+
+        assert(a);
+
+        if (!UNIT(a)->default_dependencies)
+                return 0;
+
+        if (!MANAGER_IS_SYSTEM(UNIT(a)->manager))
+                return 0;
+
+        r = unit_add_dependency_by_name(UNIT(a), UNIT_BEFORE, SPECIAL_LOCAL_FS_TARGET, true, UNIT_DEPENDENCY_DEFAULT);
+        if (r < 0)
+                return r;
+
+        r = unit_add_dependency_by_name(UNIT(a), UNIT_AFTER, SPECIAL_LOCAL_FS_PRE_TARGET, true, UNIT_DEPENDENCY_DEFAULT);
+        if (r < 0)
+                return r;
+
+        r = unit_add_two_dependencies_by_name(UNIT(a), UNIT_BEFORE, UNIT_CONFLICTS, SPECIAL_UMOUNT_TARGET, true, UNIT_DEPENDENCY_DEFAULT);
+        if (r < 0)
+                return r;
+
+        return 0;
+}
+
+static int automount_verify(Automount *a) {
+        _cleanup_free_ char *e = NULL;
+        int r;
+
+        assert(a);
+        assert(UNIT(a)->load_state == UNIT_LOADED);
+
+        if (path_equal(a->where, "/")) {
+                log_unit_error(UNIT(a), "Cannot have an automount unit for the root directory. Refusing.");
+                return -ENOEXEC;
+        }
+
+        r = unit_name_from_path(a->where, ".automount", &e);
+        if (r < 0)
+                return log_unit_error_errno(UNIT(a), r, "Failed to generate unit name from path: %m");
+
+        if (!unit_has_name(UNIT(a), e)) {
+                log_unit_error(UNIT(a), "Where= setting doesn't match unit name. Refusing.");
+                return -ENOEXEC;
+        }
+
+        return 0;
+}
+
+static int automount_set_where(Automount *a) {
+        int r;
+
+        assert(a);
+
+        if (a->where)
+                return 0;
+
+        r = unit_name_to_path(UNIT(a)->id, &a->where);
+        if (r < 0)
+                return r;
+
+        path_simplify(a->where, false);
+        return 1;
+}
+
+static int automount_add_extras(Automount *a) {
+        int r;
+
+        r = automount_set_where(a);
+        if (r < 0)
+                return r;
+
+        r = automount_add_trigger_dependencies(a);
+        if (r < 0)
+                return r;
+
+        r = automount_add_mount_dependencies(a);
+        if (r < 0)
+                return r;
+
+        return automount_add_default_dependencies(a);
+}
+
+static int automount_load(Unit *u) {
+        Automount *a = AUTOMOUNT(u);
+        int r;
+
+        assert(u);
+        assert(u->load_state == UNIT_STUB);
+
+        /* Load a .automount file */
+        r = unit_load_fragment_and_dropin(u, true);
+        if (r < 0)
+                return r;
+
+        if (u->load_state != UNIT_LOADED)
+                return 0;
+
+        r = automount_add_extras(a);
+        if (r < 0)
+                return r;
+
+        return automount_verify(a);
+}
+
+static void automount_set_state(Automount *a, AutomountState state) {
+        AutomountState old_state;
+        assert(a);
+
+        if (a->state != state)
+                bus_unit_send_pending_change_signal(UNIT(a), false);
+
+        old_state = a->state;
+        a->state = state;
+
+        if (state != AUTOMOUNT_RUNNING)
+                automount_stop_expire(a);
+
+        if (!IN_SET(state, AUTOMOUNT_WAITING, AUTOMOUNT_RUNNING))
+                unmount_autofs(a);
+
+        if (state != old_state)
+                log_unit_debug(UNIT(a), "Changed %s -> %s", automount_state_to_string(old_state), automount_state_to_string(state));
+
+        unit_notify(UNIT(a), state_translation_table[old_state], state_translation_table[state], 0);
+}
+
+static int automount_coldplug(Unit *u) {
+        Automount *a = AUTOMOUNT(u);
+        int r;
+
+        assert(a);
+        assert(a->state == AUTOMOUNT_DEAD);
+
+        if (a->deserialized_state == a->state)
+                return 0;
+
+        if (IN_SET(a->deserialized_state, AUTOMOUNT_WAITING, AUTOMOUNT_RUNNING)) {
+
+                r = automount_set_where(a);
+                if (r < 0)
+                        return r;
+
+                r = open_dev_autofs(u->manager);
+                if (r < 0)
+                        return r;
+
+                assert(a->pipe_fd >= 0);
+
+                r = sd_event_add_io(u->manager->event, &a->pipe_event_source, a->pipe_fd, EPOLLIN, automount_dispatch_io, u);
+                if (r < 0)
+                        return r;
+
+                (void) sd_event_source_set_description(a->pipe_event_source, "automount-io");
+                if (a->deserialized_state == AUTOMOUNT_RUNNING) {
+                        r = automount_start_expire(a);
+                        if (r < 0)
+                                log_unit_warning_errno(UNIT(a), r, "Failed to start expiration timer, ignoring: %m");
+                }
+
+                automount_set_state(a, a->deserialized_state);
+        }
+
+        return 0;
+}
+
+static void automount_dump(Unit *u, FILE *f, const char *prefix) {
+        char time_string[FORMAT_TIMESPAN_MAX];
+        Automount *a = AUTOMOUNT(u);
+
+        assert(a);
+
+        fprintf(f,
+                "%sAutomount State: %s\n"
+                "%sResult: %s\n"
+                "%sWhere: %s\n"
+                "%sDirectoryMode: %04o\n"
+                "%sTimeoutIdleUSec: %s\n",
+                prefix, automount_state_to_string(a->state),
+                prefix, automount_result_to_string(a->result),
+                prefix, a->where,
+                prefix, a->directory_mode,
+                prefix, format_timespan(time_string, FORMAT_TIMESPAN_MAX, a->timeout_idle_usec, USEC_PER_SEC));
+}
+
+static void automount_enter_dead(Automount *a, AutomountResult f) {
+        assert(a);
+
+        if (a->result == AUTOMOUNT_SUCCESS)
+                a->result = f;
+
+        unit_log_result(UNIT(a), a->result == AUTOMOUNT_SUCCESS, automount_result_to_string(a->result));
+        automount_set_state(a, a->result != AUTOMOUNT_SUCCESS ? AUTOMOUNT_FAILED : AUTOMOUNT_DEAD);
+}
+
+static int open_dev_autofs(Manager *m) {
+        struct autofs_dev_ioctl param;
+
+        assert(m);
+
+        if (m->dev_autofs_fd >= 0)
+                return m->dev_autofs_fd;
+
+        (void) label_fix("/dev/autofs", 0);
+
+        m->dev_autofs_fd = open("/dev/autofs", O_CLOEXEC|O_RDONLY);
+        if (m->dev_autofs_fd < 0)
+                return log_error_errno(errno, "Failed to open /dev/autofs: %m");
+
+        init_autofs_dev_ioctl(&param);
+        if (ioctl(m->dev_autofs_fd, AUTOFS_DEV_IOCTL_VERSION, &param) < 0) {
+                m->dev_autofs_fd = safe_close(m->dev_autofs_fd);
+                return -errno;
+        }
+
+        log_debug("Autofs kernel version %i.%i", param.ver_major, param.ver_minor);
+
+        return m->dev_autofs_fd;
+}
+
+static int open_ioctl_fd(int dev_autofs_fd, const char *where, dev_t devid) {
+        struct autofs_dev_ioctl *param;
+        size_t l;
+
+        assert(dev_autofs_fd >= 0);
+        assert(where);
+
+        l = sizeof(struct autofs_dev_ioctl) + strlen(where) + 1;
+        param = alloca(l);
+
+        init_autofs_dev_ioctl(param);
+        param->size = l;
+        param->ioctlfd = -1;
+        param->openmount.devid = devid;
+        strcpy(param->path, where);
+
+        if (ioctl(dev_autofs_fd, AUTOFS_DEV_IOCTL_OPENMOUNT, param) < 0)
+                return -errno;
+
+        if (param->ioctlfd < 0)
+                return -EIO;
+
+        (void) fd_cloexec(param->ioctlfd, true);
+        return param->ioctlfd;
+}
+
+static int autofs_protocol(int dev_autofs_fd, int ioctl_fd) {
+        uint32_t major, minor;
+        struct autofs_dev_ioctl param;
+
+        assert(dev_autofs_fd >= 0);
+        assert(ioctl_fd >= 0);
+
+        init_autofs_dev_ioctl(&param);
+        param.ioctlfd = ioctl_fd;
+
+        if (ioctl(dev_autofs_fd, AUTOFS_DEV_IOCTL_PROTOVER, &param) < 0)
+                return -errno;
+
+        major = param.protover.version;
+
+        init_autofs_dev_ioctl(&param);
+        param.ioctlfd = ioctl_fd;
+
+        if (ioctl(dev_autofs_fd, AUTOFS_DEV_IOCTL_PROTOSUBVER, &param) < 0)
+                return -errno;
+
+        minor = param.protosubver.sub_version;
+
+        log_debug("Autofs protocol version %i.%i", major, minor);
+        return 0;
+}
+
+static int autofs_set_timeout(int dev_autofs_fd, int ioctl_fd, usec_t usec) {
+        struct autofs_dev_ioctl param;
+
+        assert(dev_autofs_fd >= 0);
+        assert(ioctl_fd >= 0);
+
+        init_autofs_dev_ioctl(&param);
+        param.ioctlfd = ioctl_fd;
+
+        if (usec == USEC_INFINITY)
+                param.timeout.timeout = 0;
+        else
+                /* Convert to seconds, rounding up. */
+                param.timeout.timeout = DIV_ROUND_UP(usec, USEC_PER_SEC);
+
+        if (ioctl(dev_autofs_fd, AUTOFS_DEV_IOCTL_TIMEOUT, &param) < 0)
+                return -errno;
+
+        return 0;
+}
+
+static int autofs_send_ready(int dev_autofs_fd, int ioctl_fd, uint32_t token, int status) {
+        struct autofs_dev_ioctl param;
+
+        assert(dev_autofs_fd >= 0);
+        assert(ioctl_fd >= 0);
+
+        init_autofs_dev_ioctl(&param);
+        param.ioctlfd = ioctl_fd;
+
+        if (status != 0) {
+                param.fail.token = token;
+                param.fail.status = status;
+        } else
+                param.ready.token = token;
+
+        if (ioctl(dev_autofs_fd, status ? AUTOFS_DEV_IOCTL_FAIL : AUTOFS_DEV_IOCTL_READY, &param) < 0)
+                return -errno;
+
+        return 0;
+}
+
+static int automount_send_ready(Automount *a, Set *tokens, int status) {
+        _cleanup_close_ int ioctl_fd = -1;
+        unsigned token;
+        int r;
+
+        assert(a);
+        assert(status <= 0);
+
+        if (set_isempty(tokens))
+                return 0;
+
+        ioctl_fd = open_ioctl_fd(UNIT(a)->manager->dev_autofs_fd, a->where, a->dev_id);
+        if (ioctl_fd < 0)
+                return ioctl_fd;
+
+        if (status != 0)
+                log_unit_debug_errno(UNIT(a), status, "Sending failure: %m");
+        else
+                log_unit_debug(UNIT(a), "Sending success.");
+
+        r = 0;
+
+        /* Autofs thankfully does not hand out 0 as a token */
+        while ((token = PTR_TO_UINT(set_steal_first(tokens)))) {
+                int k;
+
+                /* Autofs fun fact:
+                 *
+                 * if you pass a positive status code here, kernels
+                 * prior to 4.12 will freeze! Yay! */
+
+                k = autofs_send_ready(UNIT(a)->manager->dev_autofs_fd,
+                                      ioctl_fd,
+                                      token,
+                                      status);
+                if (k < 0)
+                        r = k;
+        }
+
+        return r;
+}
+
+static void automount_trigger_notify(Unit *u, Unit *other) {
+        Automount *a = AUTOMOUNT(u);
+        int r;
+
+        assert(a);
+        assert(other);
+
+        /* Filter out invocations with bogus state */
+        assert(UNIT_IS_LOAD_COMPLETE(other->load_state));
+        assert(other->type == UNIT_MOUNT);
+
+        /* Don't propagate state changes from the mount if we are already down */
+        if (!IN_SET(a->state, AUTOMOUNT_WAITING, AUTOMOUNT_RUNNING))
+                return;
+
+        /* Propagate start limit hit state */
+        if (other->start_limit_hit) {
+                automount_enter_dead(a, AUTOMOUNT_FAILURE_MOUNT_START_LIMIT_HIT);
+                return;
+        }
+
+        /* Don't propagate anything if there's still a job queued */
+        if (other->job)
+                return;
+
+        /* The mount is successfully established */
+        if (IN_SET(MOUNT(other)->state, MOUNT_MOUNTED, MOUNT_REMOUNTING)) {
+                (void) automount_send_ready(a, a->tokens, 0);
+
+                r = automount_start_expire(a);
+                if (r < 0)
+                        log_unit_warning_errno(UNIT(a), r, "Failed to start expiration timer, ignoring: %m");
+
+                automount_set_state(a, AUTOMOUNT_RUNNING);
+        }
+
+        if (IN_SET(MOUNT(other)->state,
+                   MOUNT_MOUNTING, MOUNT_MOUNTING_DONE,
+                   MOUNT_MOUNTED, MOUNT_REMOUNTING,
+                   MOUNT_REMOUNTING_SIGTERM, MOUNT_REMOUNTING_SIGKILL,
+                   MOUNT_UNMOUNTING_SIGTERM, MOUNT_UNMOUNTING_SIGKILL,
+                   MOUNT_FAILED))
+                (void) automount_send_ready(a, a->expire_tokens, -ENODEV);
+
+        if (MOUNT(other)->state == MOUNT_DEAD)
+                (void) automount_send_ready(a, a->expire_tokens, 0);
+
+        /* The mount is in some unhappy state now, let's unfreeze any waiting clients */
+        if (IN_SET(MOUNT(other)->state,
+                   MOUNT_DEAD, MOUNT_UNMOUNTING,
+                   MOUNT_REMOUNTING_SIGTERM, MOUNT_REMOUNTING_SIGKILL,
+                   MOUNT_UNMOUNTING_SIGTERM, MOUNT_UNMOUNTING_SIGKILL,
+                   MOUNT_FAILED)) {
+
+                (void) automount_send_ready(a, a->tokens, -ENODEV);
+
+                automount_set_state(a, AUTOMOUNT_WAITING);
+        }
+}
+
+static void automount_enter_waiting(Automount *a) {
+        _cleanup_close_ int ioctl_fd = -1;
+        int p[2] = { -1, -1 };
+        char name[STRLEN("systemd-") + DECIMAL_STR_MAX(pid_t) + 1];
+        char options[STRLEN("fd=,pgrp=,minproto=5,maxproto=5,direct")
+                     + DECIMAL_STR_MAX(int) + DECIMAL_STR_MAX(gid_t) + 1];
+        bool mounted = false;
+        int r, dev_autofs_fd;
+        struct stat st;
+
+        assert(a);
+        assert(a->pipe_fd < 0);
+        assert(a->where);
+
+        set_clear(a->tokens);
+
+        r = unit_fail_if_noncanonical(UNIT(a), a->where);
+        if (r < 0)
+                goto fail;
+
+        (void) mkdir_p_label(a->where, a->directory_mode);
+
+        unit_warn_if_dir_nonempty(UNIT(a), a->where);
+
+        dev_autofs_fd = open_dev_autofs(UNIT(a)->manager);
+        if (dev_autofs_fd < 0) {
+                r = dev_autofs_fd;
+                goto fail;
+        }
+
+        if (pipe2(p, O_CLOEXEC) < 0) {
+                r = -errno;
+                goto fail;
+        }
+        r = fd_nonblock(p[0], true);
+        if (r < 0)
+                goto fail;
+
+        xsprintf(options, "fd=%i,pgrp="PID_FMT",minproto=5,maxproto=5,direct", p[1], getpgrp());
+        xsprintf(name, "systemd-"PID_FMT, getpid_cached());
+        r = mount_nofollow(name, a->where, "autofs", 0, options);
+        if (r < 0)
+                goto fail;
+
+        mounted = true;
+
+        p[1] = safe_close(p[1]);
+
+        if (stat(a->where, &st) < 0) {
+                r = -errno;
+                goto fail;
+        }
+
+        ioctl_fd = open_ioctl_fd(dev_autofs_fd, a->where, st.st_dev);
+        if (ioctl_fd < 0) {
+                r = ioctl_fd;
+                goto fail;
+        }
+
+        r = autofs_protocol(dev_autofs_fd, ioctl_fd);
+        if (r < 0)
+                goto fail;
+
+        r = autofs_set_timeout(dev_autofs_fd, ioctl_fd, a->timeout_idle_usec);
+        if (r < 0)
+                goto fail;
+
+        r = sd_event_add_io(UNIT(a)->manager->event, &a->pipe_event_source, p[0], EPOLLIN, automount_dispatch_io, a);
+        if (r < 0)
+                goto fail;
+
+        (void) sd_event_source_set_description(a->pipe_event_source, "automount-io");
+
+        a->pipe_fd = p[0];
+        a->dev_id = st.st_dev;
+
+        automount_set_state(a, AUTOMOUNT_WAITING);
+
+        return;
+
+fail:
+        log_unit_error_errno(UNIT(a), r, "Failed to initialize automounter: %m");
+
+        safe_close_pair(p);
+
+        if (mounted) {
+                r = repeat_unmount(a->where, MNT_DETACH|UMOUNT_NOFOLLOW);
+                if (r < 0)
+                        log_error_errno(r, "Failed to unmount, ignoring: %m");
+        }
+
+        automount_enter_dead(a, AUTOMOUNT_FAILURE_RESOURCES);
+}
+
+static void *expire_thread(void *p) {
+        struct autofs_dev_ioctl param;
+        _cleanup_(expire_data_freep) struct expire_data *data = (struct expire_data*)p;
+        int r;
+
+        assert(data->dev_autofs_fd >= 0);
+        assert(data->ioctl_fd >= 0);
+
+        init_autofs_dev_ioctl(&param);
+        param.ioctlfd = data->ioctl_fd;
+
+        do {
+                r = ioctl(data->dev_autofs_fd, AUTOFS_DEV_IOCTL_EXPIRE, &param);
+        } while (r >= 0);
+
+        if (errno != EAGAIN)
+                log_warning_errno(errno, "Failed to expire automount, ignoring: %m");
+
+        return NULL;
+}
+
+static int automount_dispatch_expire(sd_event_source *source, usec_t usec, void *userdata) {
+        Automount *a = AUTOMOUNT(userdata);
+        _cleanup_(expire_data_freep) struct expire_data *data = NULL;
+        int r;
+
+        assert(a);
+        assert(source == a->expire_event_source);
+
+        data = new0(struct expire_data, 1);
+        if (!data)
+                return log_oom();
+
+        data->ioctl_fd = -1;
+
+        data->dev_autofs_fd = fcntl(UNIT(a)->manager->dev_autofs_fd, F_DUPFD_CLOEXEC, 3);
+        if (data->dev_autofs_fd < 0)
+                return log_unit_error_errno(UNIT(a), errno, "Failed to duplicate autofs fd: %m");
+
+        data->ioctl_fd = open_ioctl_fd(UNIT(a)->manager->dev_autofs_fd, a->where, a->dev_id);
+        if (data->ioctl_fd < 0)
+                return log_unit_error_errno(UNIT(a), data->ioctl_fd, "Couldn't open autofs ioctl fd: %m");
+
+        r = asynchronous_job(expire_thread, data);
+        if (r < 0)
+                return log_unit_error_errno(UNIT(a), r, "Failed to start expire job: %m");
+
+        data = NULL;
+
+        return automount_start_expire(a);
+}
+
+static int automount_start_expire(Automount *a) {
+        usec_t timeout;
+        int r;
+
+        assert(a);
+
+        if (a->timeout_idle_usec == 0)
+                return 0;
+
+        timeout = MAX(a->timeout_idle_usec/3, USEC_PER_SEC);
+
+        if (a->expire_event_source) {
+                r = sd_event_source_set_time_relative(a->expire_event_source, timeout);
+                if (r < 0)
+                        return r;
+
+                return sd_event_source_set_enabled(a->expire_event_source, SD_EVENT_ONESHOT);
+        }
+
+        r = sd_event_add_time_relative(
+                        UNIT(a)->manager->event,
+                        &a->expire_event_source,
+                        CLOCK_MONOTONIC, timeout, 0,
+                        automount_dispatch_expire, a);
+        if (r < 0)
+                return r;
+
+        (void) sd_event_source_set_description(a->expire_event_source, "automount-expire");
+
+        return 0;
+}
+
+static void automount_stop_expire(Automount *a) {
+        assert(a);
+
+        if (!a->expire_event_source)
+                return;
+
+        (void) sd_event_source_set_enabled(a->expire_event_source, SD_EVENT_OFF);
+}
+
+static void automount_enter_running(Automount *a) {
+        _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
+        Unit *trigger;
+        struct stat st;
+        int r;
+
+        assert(a);
+
+        /* If the user masked our unit in the meantime, fail */
+        if (UNIT(a)->load_state != UNIT_LOADED) {
+                log_unit_error(UNIT(a), "Suppressing automount event since unit is no longer loaded.");
+                goto fail;
+        }
+
+        /* We don't take mount requests anymore if we are supposed to
+         * shut down anyway */
+        if (unit_stop_pending(UNIT(a))) {
+                log_unit_debug(UNIT(a), "Suppressing automount request since unit stop is scheduled.");
+                automount_send_ready(a, a->tokens, -EHOSTDOWN);
+                automount_send_ready(a, a->expire_tokens, -EHOSTDOWN);
+                return;
+        }
+
+        (void) mkdir_p_label(a->where, a->directory_mode);
+
+        /* Before we do anything, let's see if somebody is playing games with us? */
+        if (lstat(a->where, &st) < 0) {
+                log_unit_warning_errno(UNIT(a), errno, "Failed to stat automount point: %m");
+                goto fail;
+        }
+
+        /* The mount unit may have been explicitly started before we got the
+         * autofs request. Ack it to unblock anything waiting on the mount point. */
+        if (!S_ISDIR(st.st_mode) || st.st_dev != a->dev_id) {
+                log_unit_info(UNIT(a), "Automount point already active?");
+                automount_send_ready(a, a->tokens, 0);
+                return;
+        }
+
+        trigger = UNIT_TRIGGER(UNIT(a));
+        if (!trigger) {
+                log_unit_error(UNIT(a), "Unit to trigger vanished.");
+                goto fail;
+        }
+
+        r = manager_add_job(UNIT(a)->manager, JOB_START, trigger, JOB_REPLACE, NULL, &error, NULL);
+        if (r < 0) {
+                log_unit_warning(UNIT(a), "Failed to queue mount startup job: %s", bus_error_message(&error, r));
+                goto fail;
+        }
+
+        automount_set_state(a, AUTOMOUNT_RUNNING);
+        return;
+
+fail:
+        automount_enter_dead(a, AUTOMOUNT_FAILURE_RESOURCES);
+}
+
+static int automount_start(Unit *u) {
+        Automount *a = AUTOMOUNT(u);
+        int r;
+
+        assert(a);
+        assert(IN_SET(a->state, AUTOMOUNT_DEAD, AUTOMOUNT_FAILED));
+
+        if (path_is_mount_point(a->where, NULL, 0) > 0) {
+                log_unit_error(u, "Path %s is already a mount point, refusing start.", a->where);
+                return -EEXIST;
+        }
+
+        r = unit_test_trigger_loaded(u);
+        if (r < 0)
+                return r;
+
+        r = unit_test_start_limit(u);
+        if (r < 0) {
+                automount_enter_dead(a, AUTOMOUNT_FAILURE_START_LIMIT_HIT);
+                return r;
+        }
+
+        r = unit_acquire_invocation_id(u);
+        if (r < 0)
+                return r;
+
+        a->result = AUTOMOUNT_SUCCESS;
+        automount_enter_waiting(a);
+        return 1;
+}
+
+static int automount_stop(Unit *u) {
+        Automount *a = AUTOMOUNT(u);
+
+        assert(a);
+        assert(IN_SET(a->state, AUTOMOUNT_WAITING, AUTOMOUNT_RUNNING));
+
+        automount_enter_dead(a, AUTOMOUNT_SUCCESS);
+        return 1;
+}
+
+static int automount_serialize(Unit *u, FILE *f, FDSet *fds) {
+        Automount *a = AUTOMOUNT(u);
+        void *p;
+        int r;
+
+        assert(a);
+        assert(f);
+        assert(fds);
+
+        (void) serialize_item(f, "state", automount_state_to_string(a->state));
+        (void) serialize_item(f, "result", automount_result_to_string(a->result));
+        (void) serialize_item_format(f, "dev-id", "%lu", (unsigned long) a->dev_id);
+
+        SET_FOREACH(p, a->tokens)
+                (void) serialize_item_format(f, "token", "%u", PTR_TO_UINT(p));
+        SET_FOREACH(p, a->expire_tokens)
+                (void) serialize_item_format(f, "expire-token", "%u", PTR_TO_UINT(p));
+
+        r = serialize_fd(f, fds, "pipe-fd", a->pipe_fd);
+        if (r < 0)
+                return r;
+
+        return 0;
+}
+
+static int automount_deserialize_item(Unit *u, const char *key, const char *value, FDSet *fds) {
+        Automount *a = AUTOMOUNT(u);
+        int r;
+
+        assert(a);
+        assert(fds);
+
+        if (streq(key, "state")) {
+                AutomountState state;
+
+                state = automount_state_from_string(value);
+                if (state < 0)
+                        log_unit_debug(u, "Failed to parse state value: %s", value);
+                else
+                        a->deserialized_state = state;
+        } else if (streq(key, "result")) {
+                AutomountResult f;
+
+                f = automount_result_from_string(value);
+                if (f < 0)
+                        log_unit_debug(u, "Failed to parse result value: %s", value);
+                else if (f != AUTOMOUNT_SUCCESS)
+                        a->result = f;
+
+        } else if (streq(key, "dev-id")) {
+                unsigned long d;
+
+                if (safe_atolu(value, &d) < 0)
+                        log_unit_debug(u, "Failed to parse dev-id value: %s", value);
+                else
+                        a->dev_id = (dev_t) d;
+
+        } else if (streq(key, "token")) {
+                unsigned token;
+
+                if (safe_atou(value, &token) < 0)
+                        log_unit_debug(u, "Failed to parse token value: %s", value);
+                else {
+                        r = set_ensure_put(&a->tokens, NULL, UINT_TO_PTR(token));
+                        if (r < 0)
+                                log_unit_error_errno(u, r, "Failed to add token to set: %m");
+                }
+        } else if (streq(key, "expire-token")) {
+                unsigned token;
+
+                if (safe_atou(value, &token) < 0)
+                        log_unit_debug(u, "Failed to parse token value: %s", value);
+                else {
+                        r = set_ensure_put(&a->expire_tokens, NULL, UINT_TO_PTR(token));
+                        if (r < 0)
+                                log_unit_error_errno(u, r, "Failed to add expire token to set: %m");
+                }
+        } else if (streq(key, "pipe-fd")) {
+                int fd;
+
+                if (safe_atoi(value, &fd) < 0 || fd < 0 || !fdset_contains(fds, fd))
+                        log_unit_debug(u, "Failed to parse pipe-fd value: %s", value);
+                else {
+                        safe_close(a->pipe_fd);
+                        a->pipe_fd = fdset_remove(fds, fd);
+                }
+        } else
+                log_unit_debug(u, "Unknown serialization key: %s", key);
+
+        return 0;
+}
+
+static UnitActiveState automount_active_state(Unit *u) {
+        assert(u);
+
+        return state_translation_table[AUTOMOUNT(u)->state];
+}
+
+static const char *automount_sub_state_to_string(Unit *u) {
+        assert(u);
+
+        return automount_state_to_string(AUTOMOUNT(u)->state);
+}
+
+static bool automount_may_gc(Unit *u) {
+        Unit *t;
+
+        assert(u);
+
+        t = UNIT_TRIGGER(u);
+        if (!t)
+                return true;
+
+        return UNIT_VTABLE(t)->may_gc(t);
+}
+
+static int automount_dispatch_io(sd_event_source *s, int fd, uint32_t events, void *userdata) {
+        _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
+        union autofs_v5_packet_union packet;
+        Automount *a = AUTOMOUNT(userdata);
+        Unit *trigger;
+        int r;
+
+        assert(a);
+        assert(fd == a->pipe_fd);
+
+        if (events & (EPOLLHUP|EPOLLERR)) {
+                log_unit_error(UNIT(a), "Got hangup/error on autofs pipe from kernel. Likely our automount point has been unmounted by someone or something else?");
+                automount_enter_dead(a, AUTOMOUNT_FAILURE_UNMOUNTED);
+                return 0;
+        }
+
+        if (events != EPOLLIN) {
+                log_unit_error(UNIT(a), "Got invalid poll event %"PRIu32" on pipe (fd=%d)", events, fd);
+                goto fail;
+        }
+
+        r = loop_read_exact(a->pipe_fd, &packet, sizeof(packet), true);
+        if (r < 0) {
+                log_unit_error_errno(UNIT(a), r, "Invalid read from pipe: %m");
+                goto fail;
+        }
+
+        switch (packet.hdr.type) {
+
+        case autofs_ptype_missing_direct:
+
+                if (packet.v5_packet.pid > 0) {
+                        _cleanup_free_ char *p = NULL;
+
+                        (void) get_process_comm(packet.v5_packet.pid, &p);
+                        log_unit_info(UNIT(a), "Got automount request for %s, triggered by %"PRIu32" (%s)", a->where, packet.v5_packet.pid, strna(p));
+                } else
+                        log_unit_debug(UNIT(a), "Got direct mount request on %s", a->where);
+
+                r = set_ensure_put(&a->tokens, NULL, UINT_TO_PTR(packet.v5_packet.wait_queue_token));
+                if (r < 0) {
+                        log_unit_error_errno(UNIT(a), r, "Failed to remember token: %m");
+                        goto fail;
+                }
+
+                automount_enter_running(a);
+                break;
+
+        case autofs_ptype_expire_direct:
+                log_unit_debug(UNIT(a), "Got direct umount request on %s", a->where);
+
+                automount_stop_expire(a);
+
+                r = set_ensure_put(&a->expire_tokens, NULL, UINT_TO_PTR(packet.v5_packet.wait_queue_token));
+                if (r < 0) {
+                        log_unit_error_errno(UNIT(a), r, "Failed to remember token: %m");
+                        goto fail;
+                }
+
+                trigger = UNIT_TRIGGER(UNIT(a));
+                if (!trigger) {
+                        log_unit_error(UNIT(a), "Unit to trigger vanished.");
+                        goto fail;
+                }
+
+                r = manager_add_job(UNIT(a)->manager, JOB_STOP, trigger, JOB_REPLACE, NULL, &error, NULL);
+                if (r < 0) {
+                        log_unit_warning(UNIT(a), "Failed to queue umount startup job: %s", bus_error_message(&error, r));
+                        goto fail;
+                }
+                break;
+
+        default:
+                log_unit_error(UNIT(a), "Received unknown automount request %i", packet.hdr.type);
+                break;
+        }
+
+        return 0;
+
+fail:
+        automount_enter_dead(a, AUTOMOUNT_FAILURE_RESOURCES);
+        return 0;
+}
+
+static void automount_shutdown(Manager *m) {
+        assert(m);
+
+        m->dev_autofs_fd = safe_close(m->dev_autofs_fd);
+}
+
+static void automount_reset_failed(Unit *u) {
+        Automount *a = AUTOMOUNT(u);
+
+        assert(a);
+
+        if (a->state == AUTOMOUNT_FAILED)
+                automount_set_state(a, AUTOMOUNT_DEAD);
+
+        a->result = AUTOMOUNT_SUCCESS;
+}
+
+static bool automount_supported(void) {
+        static int supported = -1;
+
+        if (supported < 0)
+                supported = access("/dev/autofs", F_OK) >= 0;
+
+        return supported;
+}
+
+static const char* const automount_result_table[_AUTOMOUNT_RESULT_MAX] = {
+        [AUTOMOUNT_SUCCESS] = "success",
+        [AUTOMOUNT_FAILURE_RESOURCES] = "resources",
+        [AUTOMOUNT_FAILURE_START_LIMIT_HIT] = "start-limit-hit",
+        [AUTOMOUNT_FAILURE_MOUNT_START_LIMIT_HIT] = "mount-start-limit-hit",
+        [AUTOMOUNT_FAILURE_UNMOUNTED] = "unmounted",
+};
+
+DEFINE_STRING_TABLE_LOOKUP(automount_result, AutomountResult);
+
+const UnitVTable automount_vtable = {
+        .object_size = sizeof(Automount),
+
+        .sections =
+                "Unit\0"
+                "Automount\0"
+                "Install\0",
+        .private_section = "Automount",
+
+        .can_transient = true,
+        .can_fail = true,
+        .can_trigger = true,
+
+        .init = automount_init,
+        .load = automount_load,
+        .done = automount_done,
+
+        .coldplug = automount_coldplug,
+
+        .dump = automount_dump,
+
+        .start = automount_start,
+        .stop = automount_stop,
+
+        .serialize = automount_serialize,
+        .deserialize_item = automount_deserialize_item,
+
+        .active_state = automount_active_state,
+        .sub_state_to_string = automount_sub_state_to_string,
+
+        .may_gc = automount_may_gc,
+
+        .trigger_notify = automount_trigger_notify,
+
+        .reset_failed = automount_reset_failed,
+
+        .bus_set_property = bus_automount_set_property,
+
+        .shutdown = automount_shutdown,
+        .supported = automount_supported,
+
+        .status_message_formats = {
+                .finished_start_job = {
+                        [JOB_DONE]       = "Set up automount %s.",
+                        [JOB_FAILED]     = "Failed to set up automount %s.",
+                },
+                .finished_stop_job = {
+                        [JOB_DONE]       = "Unset automount %s.",
+                        [JOB_FAILED]     = "Failed to unset automount %s.",
+                },
+        },
+};