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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 15:35:18 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 15:35:18 +0000 |
commit | b750101eb236130cf056c675997decbac904cc49 (patch) | |
tree | a5df1a06754bdd014cb975c051c83b01c9a97532 /src/libsystemd/sd-bus/bus-track.c | |
parent | Initial commit. (diff) | |
download | systemd-upstream.tar.xz systemd-upstream.zip |
Adding upstream version 252.22.upstream/252.22upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to '')
-rw-r--r-- | src/libsystemd/sd-bus/bus-track.c | 495 |
1 files changed, 495 insertions, 0 deletions
diff --git a/src/libsystemd/sd-bus/bus-track.c b/src/libsystemd/sd-bus/bus-track.c new file mode 100644 index 0000000..f9c59a1 --- /dev/null +++ b/src/libsystemd/sd-bus/bus-track.c @@ -0,0 +1,495 @@ +/* SPDX-License-Identifier: LGPL-2.1-or-later */ + +#include "sd-bus.h" + +#include "alloc-util.h" +#include "bus-internal.h" +#include "bus-track.h" +#include "string-util.h" + +struct track_item { + unsigned n_ref; + char *name; + sd_bus_slot *slot; +}; + +struct sd_bus_track { + unsigned n_ref; + unsigned n_adding; /* are we in the process of adding a new name? */ + sd_bus *bus; + sd_bus_track_handler_t handler; + void *userdata; + Hashmap *names; + LIST_FIELDS(sd_bus_track, queue); + Iterator iterator; + bool in_list:1; /* In bus->tracks? */ + bool in_queue:1; /* In bus->track_queue? */ + bool modified:1; + bool recursive:1; + sd_bus_destroy_t destroy_callback; + + LIST_FIELDS(sd_bus_track, tracks); +}; + +#define MATCH_FOR_NAME(name) \ + strjoina("type='signal'," \ + "sender='org.freedesktop.DBus'," \ + "path='/org/freedesktop/DBus'," \ + "interface='org.freedesktop.DBus'," \ + "member='NameOwnerChanged'," \ + "arg0='", name, "'") + +static struct track_item* track_item_free(struct track_item *i) { + if (!i) + return NULL; + + sd_bus_slot_unref(i->slot); + free(i->name); + return mfree(i); +} + +DEFINE_PRIVATE_TRIVIAL_UNREF_FUNC(struct track_item, track_item, track_item_free); +DEFINE_TRIVIAL_CLEANUP_FUNC(struct track_item*, track_item_unref); +DEFINE_PRIVATE_HASH_OPS_WITH_VALUE_DESTRUCTOR(track_item_hash_ops, char, string_hash_func, string_compare_func, + struct track_item, track_item_free); + +static void bus_track_add_to_queue(sd_bus_track *track) { + assert(track); + + /* Adds the bus track object to the queue of objects we should dispatch next, subject to a number of + * conditions. */ + + /* Already in the queue? */ + if (track->in_queue) + return; + + /* if we are currently in the process of adding a new name, then let's not enqueue this just yet, let's wait + * until the addition is complete. */ + if (track->n_adding > 0) + return; + + /* still referenced? */ + if (hashmap_size(track->names) > 0) + return; + + /* Nothing to call? */ + if (!track->handler) + return; + + /* Already closed? */ + if (!track->in_list) + return; + + LIST_PREPEND(queue, track->bus->track_queue, track); + track->in_queue = true; +} + +static void bus_track_remove_from_queue(sd_bus_track *track) { + assert(track); + + if (!track->in_queue) + return; + + LIST_REMOVE(queue, track->bus->track_queue, track); + track->in_queue = false; +} + +static int bus_track_remove_name_fully(sd_bus_track *track, const char *name) { + struct track_item *i; + + assert(track); + assert(name); + + i = hashmap_remove(track->names, name); + if (!i) + return 0; + + track_item_free(i); + + bus_track_add_to_queue(track); + + track->modified = true; + return 1; +} + +_public_ int sd_bus_track_new( + sd_bus *bus, + sd_bus_track **track, + sd_bus_track_handler_t handler, + void *userdata) { + + sd_bus_track *t; + + assert_return(bus, -EINVAL); + assert_return(bus = bus_resolve(bus), -ENOPKG); + assert_return(track, -EINVAL); + + if (!bus->bus_client) + return -EINVAL; + + t = new0(sd_bus_track, 1); + if (!t) + return -ENOMEM; + + t->n_ref = 1; + t->handler = handler; + t->userdata = userdata; + t->bus = sd_bus_ref(bus); + + LIST_PREPEND(tracks, bus->tracks, t); + t->in_list = true; + + bus_track_add_to_queue(t); + + *track = t; + return 0; +} + +static sd_bus_track *track_free(sd_bus_track *track) { + assert(track); + + if (track->in_list) + LIST_REMOVE(tracks, track->bus->tracks, track); + + bus_track_remove_from_queue(track); + track->names = hashmap_free(track->names); + track->bus = sd_bus_unref(track->bus); + + if (track->destroy_callback) + track->destroy_callback(track->userdata); + + return mfree(track); +} + +DEFINE_PUBLIC_TRIVIAL_REF_UNREF_FUNC(sd_bus_track, sd_bus_track, track_free); + +static int on_name_owner_changed(sd_bus_message *message, void *userdata, sd_bus_error *error) { + sd_bus_track *track = ASSERT_PTR(userdata); + const char *name; + int r; + + assert(message); + + r = sd_bus_message_read(message, "sss", &name, NULL, NULL); + if (r < 0) + return 0; + + bus_track_remove_name_fully(track, name); + return 0; +} + +_public_ int sd_bus_track_add_name(sd_bus_track *track, const char *name) { + _cleanup_(track_item_unrefp) struct track_item *n = NULL; + struct track_item *i; + const char *match; + int r; + + assert_return(track, -EINVAL); + assert_return(service_name_is_valid(name), -EINVAL); + + i = hashmap_get(track->names, name); + if (i) { + if (track->recursive) { + assert(i->n_ref > 0); + + /* Manual overflow check (instead of a DEFINE_TRIVIAL_REF_FUNC() helper or so), so + * that we can return a proper error, given this is almost always called in a + * directly client controllable way, and thus better should never hit an assertion + * here. */ + if (i->n_ref >= UINT_MAX) + return -EOVERFLOW; + + i->n_ref++; + } + + bus_track_remove_from_queue(track); + return 0; + } + + r = hashmap_ensure_allocated(&track->names, &track_item_hash_ops); + if (r < 0) + return r; + + n = new(struct track_item, 1); + if (!n) + return -ENOMEM; + + *n = (struct track_item) { + .n_ref = 1, + }; + + n->name = strdup(name); + if (!n->name) + return -ENOMEM; + + /* First, subscribe to this name */ + match = MATCH_FOR_NAME(name); + + bus_track_remove_from_queue(track); /* don't dispatch this while we work in it */ + + r = sd_bus_add_match_async(track->bus, &n->slot, match, on_name_owner_changed, NULL, track); + if (r < 0) { + bus_track_add_to_queue(track); + return r; + } + + r = hashmap_put(track->names, n->name, n); + if (r < 0) { + bus_track_add_to_queue(track); + return r; + } + + /* Second, check if it is currently existing, or maybe doesn't, or maybe disappeared already. */ + track->n_adding++; /* again, make sure this isn't dispatch while we are working in it */ + r = sd_bus_get_name_creds(track->bus, name, 0, NULL); + track->n_adding--; + if (r < 0) { + hashmap_remove(track->names, name); + bus_track_add_to_queue(track); + return r; + } + + TAKE_PTR(n); + + bus_track_remove_from_queue(track); + track->modified = true; + + return 1; +} + +_public_ int sd_bus_track_remove_name(sd_bus_track *track, const char *name) { + struct track_item *i; + + assert_return(name, -EINVAL); + + if (!track) /* Treat a NULL track object as an empty track object */ + return 0; + + i = hashmap_get(track->names, name); + if (!i) + return 0; + + assert(i->n_ref >= 1); + if (i->n_ref <= 1) + return bus_track_remove_name_fully(track, name); + + track_item_unref(i); + + return 1; +} + +_public_ unsigned sd_bus_track_count(sd_bus_track *track) { + + if (!track) /* Let's consider a NULL object equivalent to an empty object */ + return 0; + + /* This signature really should have returned an int, so that we can propagate errors. But well, ... Also, note + * that this returns the number of names being watched, and multiple references to the same name are not + * counted. */ + + return hashmap_size(track->names); +} + +_public_ const char* sd_bus_track_contains(sd_bus_track *track, const char *name) { + assert_return(name, NULL); + + if (!track) /* Let's consider a NULL object equivalent to an empty object */ + return NULL; + + return hashmap_contains(track->names, name) ? name : NULL; +} + +_public_ const char* sd_bus_track_first(sd_bus_track *track) { + const char *n = NULL; + + if (!track) + return NULL; + + track->modified = false; + track->iterator = ITERATOR_FIRST; + + (void) hashmap_iterate(track->names, &track->iterator, NULL, (const void**) &n); + return n; +} + +_public_ const char* sd_bus_track_next(sd_bus_track *track) { + const char *n = NULL; + + if (!track) + return NULL; + + if (track->modified) + return NULL; + + (void) hashmap_iterate(track->names, &track->iterator, NULL, (const void**) &n); + return n; +} + +_public_ int sd_bus_track_add_sender(sd_bus_track *track, sd_bus_message *m) { + const char *sender; + + assert_return(track, -EINVAL); + assert_return(m, -EINVAL); + + if (sd_bus_message_get_bus(m) != track->bus) + return -EINVAL; + + sender = sd_bus_message_get_sender(m); + if (!sender) + return -EINVAL; + + return sd_bus_track_add_name(track, sender); +} + +_public_ int sd_bus_track_remove_sender(sd_bus_track *track, sd_bus_message *m) { + const char *sender; + + assert_return(m, -EINVAL); + + if (!track) /* Treat a NULL track object as an empty track object */ + return 0; + + if (sd_bus_message_get_bus(m) != track->bus) + return -EINVAL; + + sender = sd_bus_message_get_sender(m); + if (!sender) + return -EINVAL; + + return sd_bus_track_remove_name(track, sender); +} + +_public_ sd_bus* sd_bus_track_get_bus(sd_bus_track *track) { + assert_return(track, NULL); + + return track->bus; +} + +void bus_track_dispatch(sd_bus_track *track) { + int r; + + assert(track); + assert(track->handler); + + bus_track_remove_from_queue(track); + + sd_bus_track_ref(track); + + r = track->handler(track, track->userdata); + if (r < 0) + log_debug_errno(r, "Failed to process track handler: %m"); + else if (r == 0) + bus_track_add_to_queue(track); + + sd_bus_track_unref(track); +} + +void bus_track_close(sd_bus_track *track) { + assert(track); + + /* Called whenever our bus connected is closed. If so, and our track object is non-empty, dispatch it + * immediately, as we are closing now, but first flush out all names. */ + + if (!track->in_list) + return; /* We already closed this one, don't close it again. */ + + /* Remember that this one is closed now */ + LIST_REMOVE(tracks, track->bus->tracks, track); + track->in_list = false; + + /* If there's no name in this one anyway, we don't have to dispatch */ + if (hashmap_isempty(track->names)) + return; + + /* Let's flush out all names */ + hashmap_clear(track->names); + + /* Invoke handler */ + if (track->handler) + bus_track_dispatch(track); +} + +_public_ void *sd_bus_track_get_userdata(sd_bus_track *track) { + assert_return(track, NULL); + + return track->userdata; +} + +_public_ void *sd_bus_track_set_userdata(sd_bus_track *track, void *userdata) { + void *ret; + + assert_return(track, NULL); + + ret = track->userdata; + track->userdata = userdata; + + return ret; +} + +_public_ int sd_bus_track_set_destroy_callback(sd_bus_track *track, sd_bus_destroy_t callback) { + assert_return(track, -EINVAL); + + track->destroy_callback = callback; + return 0; +} + +_public_ int sd_bus_track_get_destroy_callback(sd_bus_track *track, sd_bus_destroy_t *ret) { + assert_return(track, -EINVAL); + + if (ret) + *ret = track->destroy_callback; + + return !!track->destroy_callback; +} + +_public_ int sd_bus_track_set_recursive(sd_bus_track *track, int b) { + assert_return(track, -EINVAL); + + if (track->recursive == !!b) + return 0; + + if (!hashmap_isempty(track->names)) + return -EBUSY; + + track->recursive = b; + return 0; +} + +_public_ int sd_bus_track_get_recursive(sd_bus_track *track) { + assert_return(track, -EINVAL); + + return track->recursive; +} + +_public_ int sd_bus_track_count_sender(sd_bus_track *track, sd_bus_message *m) { + const char *sender; + + assert_return(m, -EINVAL); + + if (!track) /* Let's consider a NULL object equivalent to an empty object */ + return 0; + + if (sd_bus_message_get_bus(m) != track->bus) + return -EINVAL; + + sender = sd_bus_message_get_sender(m); + if (!sender) + return -EINVAL; + + return sd_bus_track_count_name(track, sender); +} + +_public_ int sd_bus_track_count_name(sd_bus_track *track, const char *name) { + struct track_item *i; + + assert_return(service_name_is_valid(name), -EINVAL); + + if (!track) /* Let's consider a NULL object equivalent to an empty object */ + return 0; + + i = hashmap_get(track->names, name); + if (!i) + return 0; + + return i->n_ref; +} |