stuff

1 files changed, 778 insertions, 0 deletions

diff --git a/src/libcore/path.c b/src/libcore/path.c
new file mode 100644
index 0000000000..460c1d3bf2
--- /dev/null
+++ b/src/libcore/path.c
@@ -0,0 +1,778 @@
+/***
+  This file is part of systemd.
+
+  Copyright 2010 Lennart Poettering
+
+  systemd is free software; you can redistribute it and/or modify it
+  under the terms of the GNU Lesser General Public License as published by
+  the Free Software Foundation; either version 2.1 of the License, or
+  (at your option) any later version.
+
+  systemd is distributed in the hope that it will be useful, but
+  WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+  Lesser General Public License for more details.
+
+  You should have received a copy of the GNU Lesser General Public License
+  along with systemd; If not, see <http://www.gnu.org/licenses/>.
+***/
+
+#include <errno.h>
+#include <sys/epoll.h>
+#include <sys/inotify.h>
+#include <unistd.h>
+
+#include "bus-error.h"
+#include "bus-util.h"
+#include "dbus-path.h"
+#include "fd-util.h"
+#include "fs-util.h"
+#include "glob-util.h"
+#include "macro.h"
+#include "mkdir.h"
+#include "path.h"
+#include "special.h"
+#include "stat-util.h"
+#include "string-table.h"
+#include "string-util.h"
+#include "unit-name.h"
+#include "unit.h"
+
+static const UnitActiveState state_translation_table[_PATH_STATE_MAX] = {
+        [PATH_DEAD] = UNIT_INACTIVE,
+        [PATH_WAITING] = UNIT_ACTIVE,
+        [PATH_RUNNING] = UNIT_ACTIVE,
+        [PATH_FAILED] = UNIT_FAILED
+};
+
+static int path_dispatch_io(sd_event_source *source, int fd, uint32_t revents, void *userdata);
+
+int path_spec_watch(PathSpec *s, sd_event_io_handler_t handler) {
+
+        static const int flags_table[_PATH_TYPE_MAX] = {
+                [PATH_EXISTS] = IN_DELETE_SELF|IN_MOVE_SELF|IN_ATTRIB,
+                [PATH_EXISTS_GLOB] = IN_DELETE_SELF|IN_MOVE_SELF|IN_ATTRIB,
+                [PATH_CHANGED] = IN_DELETE_SELF|IN_MOVE_SELF|IN_ATTRIB|IN_CLOSE_WRITE|IN_CREATE|IN_DELETE|IN_MOVED_FROM|IN_MOVED_TO,
+                [PATH_MODIFIED] = IN_DELETE_SELF|IN_MOVE_SELF|IN_ATTRIB|IN_CLOSE_WRITE|IN_CREATE|IN_DELETE|IN_MOVED_FROM|IN_MOVED_TO|IN_MODIFY,
+                [PATH_DIRECTORY_NOT_EMPTY] = IN_DELETE_SELF|IN_MOVE_SELF|IN_ATTRIB|IN_CREATE|IN_MOVED_TO
+        };
+
+        bool exists = false;
+        char *slash, *oldslash = NULL;
+        int r;
+
+        assert(s);
+        assert(s->unit);
+        assert(handler);
+
+        path_spec_unwatch(s);
+
+        s->inotify_fd = inotify_init1(IN_NONBLOCK|IN_CLOEXEC);
+        if (s->inotify_fd < 0) {
+                r = -errno;
+                goto fail;
+        }
+
+        r = sd_event_add_io(s->unit->manager->event, &s->event_source, s->inotify_fd, EPOLLIN, handler, s);
+        if (r < 0)
+                goto fail;
+
+        (void) sd_event_source_set_description(s->event_source, "path");
+
+        /* This assumes the path was passed through path_kill_slashes()! */
+
+        for (slash = strchr(s->path, '/'); ; slash = strchr(slash+1, '/')) {
+                char *cut = NULL;
+                int flags;
+                char tmp;
+
+                if (slash) {
+                        cut = slash + (slash == s->path);
+                        tmp = *cut;
+                        *cut = '\0';
+
+                        flags = IN_MOVE_SELF | IN_DELETE_SELF | IN_ATTRIB | IN_CREATE | IN_MOVED_TO;
+                } else
+                        flags = flags_table[s->type];
+
+                r = inotify_add_watch(s->inotify_fd, s->path, flags);
+                if (r < 0) {
+                        if (errno == EACCES || errno == ENOENT) {
+                                if (cut)
+                                        *cut = tmp;
+                                break;
+                        }
+
+                        r = log_warning_errno(errno, "Failed to add watch on %s: %s", s->path, errno == ENOSPC ? "too many watches" : strerror(-r));
+                        if (cut)
+                                *cut = tmp;
+                        goto fail;
+                } else {
+                        exists = true;
+
+                        /* Path exists, we don't need to watch parent
+                           too closely. */
+                        if (oldslash) {
+                                char *cut2 = oldslash + (oldslash == s->path);
+                                char tmp2 = *cut2;
+                                *cut2 = '\0';
+
+                                inotify_add_watch(s->inotify_fd, s->path, IN_MOVE_SELF);
+                                /* Error is ignored, the worst can happen is
+                                   we get spurious events. */
+
+                                *cut2 = tmp2;
+                        }
+                }
+
+                if (cut)
+                        *cut = tmp;
+
+                if (slash)
+                        oldslash = slash;
+                else {
+                        /* whole path has been iterated over */
+                        s->primary_wd = r;
+                        break;
+                }
+        }
+
+        if (!exists) {
+                r = log_error_errno(errno, "Failed to add watch on any of the components of %s: %m", s->path);
+                /* either EACCESS or ENOENT */
+                goto fail;
+        }
+
+        return 0;
+
+fail:
+        path_spec_unwatch(s);
+        return r;
+}
+
+void path_spec_unwatch(PathSpec *s) {
+        assert(s);
+
+        s->event_source = sd_event_source_unref(s->event_source);
+        s->inotify_fd = safe_close(s->inotify_fd);
+}
+
+int path_spec_fd_event(PathSpec *s, uint32_t revents) {
+        union inotify_event_buffer buffer;
+        struct inotify_event *e;
+        ssize_t l;
+        int r = 0;
+
+        if (revents != EPOLLIN) {
+                log_error("Got invalid poll event on inotify.");
+                return -EINVAL;
+        }
+
+        l = read(s->inotify_fd, &buffer, sizeof(buffer));
+        if (l < 0) {
+                if (errno == EAGAIN || errno == EINTR)
+                        return 0;
+
+                return log_error_errno(errno, "Failed to read inotify event: %m");
+        }
+
+        FOREACH_INOTIFY_EVENT(e, buffer, l) {
+                if ((s->type == PATH_CHANGED || s->type == PATH_MODIFIED) &&
+                    s->primary_wd == e->wd)
+                        r = 1;
+        }
+
+        return r;
+}
+
+static bool path_spec_check_good(PathSpec *s, bool initial) {
+        bool good = false;
+
+        switch (s->type) {
+
+        case PATH_EXISTS:
+                good = access(s->path, F_OK) >= 0;
+                break;
+
+        case PATH_EXISTS_GLOB:
+                good = glob_exists(s->path) > 0;
+                break;
+
+        case PATH_DIRECTORY_NOT_EMPTY: {
+                int k;
+
+                k = dir_is_empty(s->path);
+                good = !(k == -ENOENT || k > 0);
+                break;
+        }
+
+        case PATH_CHANGED:
+        case PATH_MODIFIED: {
+                bool b;
+
+                b = access(s->path, F_OK) >= 0;
+                good = !initial && b != s->previous_exists;
+                s->previous_exists = b;
+                break;
+        }
+
+        default:
+                ;
+        }
+
+        return good;
+}
+
+static void path_spec_mkdir(PathSpec *s, mode_t mode) {
+        int r;
+
+        if (s->type == PATH_EXISTS || s->type == PATH_EXISTS_GLOB)
+                return;
+
+        r = mkdir_p_label(s->path, mode);
+        if (r < 0)
+                log_warning_errno(r, "mkdir(%s) failed: %m", s->path);
+}
+
+static void path_spec_dump(PathSpec *s, FILE *f, const char *prefix) {
+        fprintf(f,
+                "%s%s: %s\n",
+                prefix,
+                path_type_to_string(s->type),
+                s->path);
+}
+
+void path_spec_done(PathSpec *s) {
+        assert(s);
+        assert(s->inotify_fd == -1);
+
+        free(s->path);
+}
+
+static void path_init(Unit *u) {
+        Path *p = PATH(u);
+
+        assert(u);
+        assert(u->load_state == UNIT_STUB);
+
+        p->directory_mode = 0755;
+}
+
+void path_free_specs(Path *p) {
+        PathSpec *s;
+
+        assert(p);
+
+        while ((s = p->specs)) {
+                path_spec_unwatch(s);
+                LIST_REMOVE(spec, p->specs, s);
+                path_spec_done(s);
+                free(s);
+        }
+}
+
+static void path_done(Unit *u) {
+        Path *p = PATH(u);
+
+        assert(p);
+
+        path_free_specs(p);
+}
+
+static int path_add_mount_links(Path *p) {
+        PathSpec *s;
+        int r;
+
+        assert(p);
+
+        LIST_FOREACH(spec, s, p->specs) {
+                r = unit_require_mounts_for(UNIT(p), s->path);
+                if (r < 0)
+                        return r;
+        }
+
+        return 0;
+}
+
+static int path_verify(Path *p) {
+        assert(p);
+
+        if (UNIT(p)->load_state != UNIT_LOADED)
+                return 0;
+
+        if (!p->specs) {
+                log_unit_error(UNIT(p), "Path unit lacks path setting. Refusing.");
+                return -EINVAL;
+        }
+
+        return 0;
+}
+
+static int path_add_default_dependencies(Path *p) {
+        int r;
+
+        assert(p);
+
+        if (!UNIT(p)->default_dependencies)
+                return 0;
+
+        r = unit_add_dependency_by_name(UNIT(p), UNIT_BEFORE, SPECIAL_PATHS_TARGET, NULL, true);
+        if (r < 0)
+                return r;
+
+        if (UNIT(p)->manager->running_as == MANAGER_SYSTEM) {
+                r = unit_add_two_dependencies_by_name(UNIT(p), UNIT_AFTER, UNIT_REQUIRES, SPECIAL_SYSINIT_TARGET, NULL, true);
+                if (r < 0)
+                        return r;
+        }
+
+        return unit_add_two_dependencies_by_name(UNIT(p), UNIT_BEFORE, UNIT_CONFLICTS, SPECIAL_SHUTDOWN_TARGET, NULL, true);
+}
+
+static int path_load(Unit *u) {
+        Path *p = PATH(u);
+        int r;
+
+        assert(u);
+        assert(u->load_state == UNIT_STUB);
+
+        r = unit_load_fragment_and_dropin(u);
+        if (r < 0)
+                return r;
+
+        if (u->load_state == UNIT_LOADED) {
+
+                if (set_isempty(u->dependencies[UNIT_TRIGGERS])) {
+                        Unit *x;
+
+                        r = unit_load_related_unit(u, ".service", &x);
+                        if (r < 0)
+                                return r;
+
+                        r = unit_add_two_dependencies(u, UNIT_BEFORE, UNIT_TRIGGERS, x, true);
+                        if (r < 0)
+                                return r;
+                }
+
+                r = path_add_mount_links(p);
+                if (r < 0)
+                        return r;
+
+                r = path_add_default_dependencies(p);
+                if (r < 0)
+                        return r;
+        }
+
+        return path_verify(p);
+}
+
+static void path_dump(Unit *u, FILE *f, const char *prefix) {
+        Path *p = PATH(u);
+        Unit *trigger;
+        PathSpec *s;
+
+        assert(p);
+        assert(f);
+
+        trigger = UNIT_TRIGGER(u);
+
+        fprintf(f,
+                "%sPath State: %s\n"
+                "%sResult: %s\n"
+                "%sUnit: %s\n"
+                "%sMakeDirectory: %s\n"
+                "%sDirectoryMode: %04o\n",
+                prefix, path_state_to_string(p->state),
+                prefix, path_result_to_string(p->result),
+                prefix, trigger ? trigger->id : "n/a",
+                prefix, yes_no(p->make_directory),
+                prefix, p->directory_mode);
+
+        LIST_FOREACH(spec, s, p->specs)
+                path_spec_dump(s, f, prefix);
+}
+
+static void path_unwatch(Path *p) {
+        PathSpec *s;
+
+        assert(p);
+
+        LIST_FOREACH(spec, s, p->specs)
+                path_spec_unwatch(s);
+}
+
+static int path_watch(Path *p) {
+        int r;
+        PathSpec *s;
+
+        assert(p);
+
+        LIST_FOREACH(spec, s, p->specs) {
+                r = path_spec_watch(s, path_dispatch_io);
+                if (r < 0)
+                        return r;
+        }
+
+        return 0;
+}
+
+static void path_set_state(Path *p, PathState state) {
+        PathState old_state;
+        assert(p);
+
+        old_state = p->state;
+        p->state = state;
+
+        if (state != PATH_WAITING &&
+            (state != PATH_RUNNING || p->inotify_triggered))
+                path_unwatch(p);
+
+        if (state != old_state)
+                log_unit_debug(UNIT(p), "Changed %s -> %s", path_state_to_string(old_state), path_state_to_string(state));
+
+        unit_notify(UNIT(p), state_translation_table[old_state], state_translation_table[state], true);
+}
+
+static void path_enter_waiting(Path *p, bool initial, bool recheck);
+
+static int path_coldplug(Unit *u) {
+        Path *p = PATH(u);
+
+        assert(p);
+        assert(p->state == PATH_DEAD);
+
+        if (p->deserialized_state != p->state) {
+
+                if (p->deserialized_state == PATH_WAITING ||
+                    p->deserialized_state == PATH_RUNNING)
+                        path_enter_waiting(p, true, true);
+                else
+                        path_set_state(p, p->deserialized_state);
+        }
+
+        return 0;
+}
+
+static void path_enter_dead(Path *p, PathResult f) {
+        assert(p);
+
+        if (f != PATH_SUCCESS)
+                p->result = f;
+
+        path_set_state(p, p->result != PATH_SUCCESS ? PATH_FAILED : PATH_DEAD);
+}
+
+static void path_enter_running(Path *p) {
+        _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
+        Unit *trigger;
+        int r;
+
+        assert(p);
+
+        /* Don't start job if we are supposed to go down */
+        if (unit_stop_pending(UNIT(p)))
+                return;
+
+        trigger = UNIT_TRIGGER(UNIT(p));
+        if (!trigger) {
+                log_unit_error(UNIT(p), "Unit to trigger vanished.");
+                path_enter_dead(p, TIMER_FAILURE_RESOURCES);
+                return;
+        }
+
+        r = manager_add_job(UNIT(p)->manager, JOB_START, trigger, JOB_REPLACE, &error, NULL);
+        if (r < 0)
+                goto fail;
+
+        p->inotify_triggered = false;
+
+        r = path_watch(p);
+        if (r < 0)
+                goto fail;
+
+        path_set_state(p, PATH_RUNNING);
+        return;
+
+fail:
+        log_unit_warning(UNIT(p), "Failed to queue unit startup job: %s", bus_error_message(&error, r));
+        path_enter_dead(p, PATH_FAILURE_RESOURCES);
+}
+
+static bool path_check_good(Path *p, bool initial) {
+        PathSpec *s;
+        bool good = false;
+
+        assert(p);
+
+        LIST_FOREACH(spec, s, p->specs) {
+                good = path_spec_check_good(s, initial);
+
+                if (good)
+                        break;
+        }
+
+        return good;
+}
+
+static void path_enter_waiting(Path *p, bool initial, bool recheck) {
+        int r;
+
+        if (recheck)
+                if (path_check_good(p, initial)) {
+                        log_unit_debug(UNIT(p), "Got triggered.");
+                        path_enter_running(p);
+                        return;
+                }
+
+        r = path_watch(p);
+        if (r < 0)
+                goto fail;
+
+        /* Hmm, so now we have created inotify watches, but the file
+         * might have appeared/been removed by now, so we must
+         * recheck */
+
+        if (recheck)
+                if (path_check_good(p, false)) {
+                        log_unit_debug(UNIT(p), "Got triggered.");
+                        path_enter_running(p);
+                        return;
+                }
+
+        path_set_state(p, PATH_WAITING);
+        return;
+
+fail:
+        log_unit_warning_errno(UNIT(p), r, "Failed to enter waiting state: %m");
+        path_enter_dead(p, PATH_FAILURE_RESOURCES);
+}
+
+static void path_mkdir(Path *p) {
+        PathSpec *s;
+
+        assert(p);
+
+        if (!p->make_directory)
+                return;
+
+        LIST_FOREACH(spec, s, p->specs)
+                path_spec_mkdir(s, p->directory_mode);
+}
+
+static int path_start(Unit *u) {
+        Path *p = PATH(u);
+        Unit *trigger;
+
+        assert(p);
+        assert(p->state == PATH_DEAD || p->state == PATH_FAILED);
+
+        trigger = UNIT_TRIGGER(u);
+        if (!trigger || trigger->load_state != UNIT_LOADED) {
+                log_unit_error(u, "Refusing to start, unit to trigger not loaded.");
+                return -ENOENT;
+        }
+
+        path_mkdir(p);
+
+        p->result = PATH_SUCCESS;
+        path_enter_waiting(p, true, true);
+
+        return 1;
+}
+
+static int path_stop(Unit *u) {
+        Path *p = PATH(u);
+
+        assert(p);
+        assert(p->state == PATH_WAITING || p->state == PATH_RUNNING);
+
+        path_enter_dead(p, PATH_SUCCESS);
+        return 1;
+}
+
+static int path_serialize(Unit *u, FILE *f, FDSet *fds) {
+        Path *p = PATH(u);
+
+        assert(u);
+        assert(f);
+        assert(fds);
+
+        unit_serialize_item(u, f, "state", path_state_to_string(p->state));
+        unit_serialize_item(u, f, "result", path_result_to_string(p->result));
+
+        return 0;
+}
+
+static int path_deserialize_item(Unit *u, const char *key, const char *value, FDSet *fds) {
+        Path *p = PATH(u);
+
+        assert(u);
+        assert(key);
+        assert(value);
+        assert(fds);
+
+        if (streq(key, "state")) {
+                PathState state;
+
+                state = path_state_from_string(value);
+                if (state < 0)
+                        log_unit_debug(u, "Failed to parse state value: %s", value);
+                else
+                        p->deserialized_state = state;
+
+        } else if (streq(key, "result")) {
+                PathResult f;
+
+                f = path_result_from_string(value);
+                if (f < 0)
+                        log_unit_debug(u, "Failed to parse result value: %s", value);
+                else if (f != PATH_SUCCESS)
+                        p->result = f;
+
+        } else
+                log_unit_debug(u, "Unknown serialization key: %s", key);
+
+        return 0;
+}
+
+_pure_ static UnitActiveState path_active_state(Unit *u) {
+        assert(u);
+
+        return state_translation_table[PATH(u)->state];
+}
+
+_pure_ static const char *path_sub_state_to_string(Unit *u) {
+        assert(u);
+
+        return path_state_to_string(PATH(u)->state);
+}
+
+static int path_dispatch_io(sd_event_source *source, int fd, uint32_t revents, void *userdata) {
+        PathSpec *s = userdata;
+        Path *p;
+        int changed;
+
+        assert(s);
+        assert(s->unit);
+        assert(fd >= 0);
+
+        p = PATH(s->unit);
+
+        if (p->state != PATH_WAITING &&
+            p->state != PATH_RUNNING)
+                return 0;
+
+        /* log_debug("inotify wakeup on %s.", u->id); */
+
+        LIST_FOREACH(spec, s, p->specs)
+                if (path_spec_owns_inotify_fd(s, fd))
+                        break;
+
+        if (!s) {
+                log_error("Got event on unknown fd.");
+                goto fail;
+        }
+
+        changed = path_spec_fd_event(s, revents);
+        if (changed < 0)
+                goto fail;
+
+        /* If we are already running, then remember that one event was
+         * dispatched so that we restart the service only if something
+         * actually changed on disk */
+        p->inotify_triggered = true;
+
+        if (changed)
+                path_enter_running(p);
+        else
+                path_enter_waiting(p, false, true);
+
+        return 0;
+
+fail:
+        path_enter_dead(p, PATH_FAILURE_RESOURCES);
+        return 0;
+}
+
+static void path_trigger_notify(Unit *u, Unit *other) {
+        Path *p = PATH(u);
+
+        assert(u);
+        assert(other);
+
+        /* Invoked whenever the unit we trigger changes state or gains
+         * or loses a job */
+
+        if (other->load_state != UNIT_LOADED)
+                return;
+
+        if (p->state == PATH_RUNNING &&
+            UNIT_IS_INACTIVE_OR_FAILED(unit_active_state(other))) {
+                log_unit_debug(UNIT(p), "Got notified about unit deactivation.");
+
+                /* Hmm, so inotify was triggered since the
+                 * last activation, so I guess we need to
+                 * recheck what is going on. */
+                path_enter_waiting(p, false, p->inotify_triggered);
+        }
+}
+
+static void path_reset_failed(Unit *u) {
+        Path *p = PATH(u);
+
+        assert(p);
+
+        if (p->state == PATH_FAILED)
+                path_set_state(p, PATH_DEAD);
+
+        p->result = PATH_SUCCESS;
+}
+
+static const char* const path_type_table[_PATH_TYPE_MAX] = {
+        [PATH_EXISTS] = "PathExists",
+        [PATH_EXISTS_GLOB] = "PathExistsGlob",
+        [PATH_DIRECTORY_NOT_EMPTY] = "DirectoryNotEmpty",
+        [PATH_CHANGED] = "PathChanged",
+        [PATH_MODIFIED] = "PathModified",
+};
+
+DEFINE_STRING_TABLE_LOOKUP(path_type, PathType);
+
+static const char* const path_result_table[_PATH_RESULT_MAX] = {
+        [PATH_SUCCESS] = "success",
+        [PATH_FAILURE_RESOURCES] = "resources",
+};
+
+DEFINE_STRING_TABLE_LOOKUP(path_result, PathResult);
+
+const UnitVTable path_vtable = {
+        .object_size = sizeof(Path),
+
+        .sections =
+                "Unit\0"
+                "Path\0"
+                "Install\0",
+
+        .init = path_init,
+        .done = path_done,
+        .load = path_load,
+
+        .coldplug = path_coldplug,
+
+        .dump = path_dump,
+
+        .start = path_start,
+        .stop = path_stop,
+
+        .serialize = path_serialize,
+        .deserialize_item = path_deserialize_item,
+
+        .active_state = path_active_state,
+        .sub_state_to_string = path_sub_state_to_string,
+
+        .trigger_notify = path_trigger_notify,
+
+        .reset_failed = path_reset_failed,
+
+        .bus_vtable = bus_path_vtable
+};