Commit 7286037f authored by Lennart Poettering's avatar Lennart Poettering

bus: properly detect and handle if a callback is installed/removed from within a callback

parent 6807947e
......@@ -46,6 +46,8 @@ struct filter_callback {
sd_bus_message_handler_t callback;
void *userdata;
unsigned last_iteration;
LIST_FIELDS(struct filter_callback, callbacks);
};
......@@ -55,6 +57,8 @@ struct object_callback {
char *path;
bool is_fallback;
unsigned last_iteration;
};
enum bus_state {
......@@ -86,6 +90,9 @@ struct sd_bus {
bool prefer_readv:1;
bool prefer_writev:1;
bool processing:1;
bool match_callbacks_modified:1;
bool filter_callbacks_modified:1;
bool object_callbacks_modified:1;
void *rbuffer;
size_t rbuffer_size;
......@@ -139,6 +146,7 @@ struct sd_bus {
char **exec_argv;
uint64_t hello_serial;
unsigned iteration_counter;
};
static inline void bus_unrefp(sd_bus **b) {
......
......@@ -212,6 +212,9 @@ int bus_match_run(
if (!node)
return 0;
if (bus && bus->match_callbacks_modified)
return 0;
/* Not these special semantics: when traversing the tree we
* usually let bus_match_run() when called for a node
* recursively invoke bus_match_run(). There's are two
......@@ -241,6 +244,13 @@ int bus_match_run(
case BUS_MATCH_LEAF:
if (bus) {
if (node->leaf.last_iteration == bus->iteration_counter)
return 0;
node->leaf.last_iteration = bus->iteration_counter;
}
/* Run the callback. And then invoke siblings. */
assert(node->leaf.callback);
r = node->leaf.callback(bus, ret, m, node->leaf.userdata);
......@@ -323,6 +333,9 @@ int bus_match_run(
}
}
if (bus && bus->match_callbacks_modified)
return 0;
/* And now, let's invoke our siblings */
return bus_match_run(bus, node->next, ret, m);
}
......
......@@ -54,12 +54,13 @@ struct bus_match_node {
union {
struct {
uint8_t u8;
char *str;
uint8_t u8;
} value;
struct {
sd_bus_message_handler_t callback;
void *userdata;
unsigned last_iteration;
} leaf;
struct {
/* If this is set, then the child is NULL */
......
......@@ -1517,20 +1517,47 @@ static int process_filter(sd_bus *bus, sd_bus_message *m) {
assert(bus);
assert(m);
do {
bus->filter_callbacks_modified = false;
LIST_FOREACH(callbacks, l, bus->filter_callbacks) {
if (bus->filter_callbacks_modified)
break;
/* Don't run this more than once per iteration */
if (l->last_iteration == bus->iteration_counter)
continue;
l->last_iteration = bus->iteration_counter;
r = l->callback(bus, 0, m, l->userdata);
if (r != 0)
return r;
}
} while (bus->filter_callbacks_modified);
return 0;
}
static int process_match(sd_bus *bus, sd_bus_message *m) {
int r;
assert(bus);
assert(m);
return bus_match_run(bus, &bus->match_callbacks, 0, m);
do {
bus->match_callbacks_modified = false;
r = bus_match_run(bus, &bus->match_callbacks, 0, m);
if (r != 0)
return r;
} while (bus->match_callbacks_modified);
return 0;
}
static int process_builtin(sd_bus *bus, sd_bus_message *m) {
......@@ -1588,9 +1615,9 @@ static int process_object(sd_bus *bus, sd_bus_message *m) {
_cleanup_bus_error_free_ sd_bus_error error = SD_BUS_ERROR_INIT;
_cleanup_bus_message_unref_ sd_bus_message *reply = NULL;
struct object_callback *c;
char *p;
int r;
bool found = false;
size_t pl;
assert(bus);
assert(m);
......@@ -1601,8 +1628,18 @@ static int process_object(sd_bus *bus, sd_bus_message *m) {
if (hashmap_isempty(bus->object_callbacks))
return 0;
pl = strlen(m->path);
do {
char p[pl+1];
bus->object_callbacks_modified = false;
c = hashmap_get(bus->object_callbacks, m->path);
if (c) {
if (c && c->last_iteration != bus->iteration_counter) {
c->last_iteration = bus->iteration_counter;
r = c->callback(bus, 0, m, c->userdata);
if (r != 0)
return r;
......@@ -1611,10 +1648,13 @@ static int process_object(sd_bus *bus, sd_bus_message *m) {
}
/* Look for fallback prefixes */
p = strdupa(m->path);
strcpy(p, m->path);
for (;;) {
char *e;
if (bus->object_callbacks_modified)
break;
e = strrchr(p, '/');
if (e == p || !e)
break;
......@@ -1622,7 +1662,10 @@ static int process_object(sd_bus *bus, sd_bus_message *m) {
*e = 0;
c = hashmap_get(bus->object_callbacks, p);
if (c && c->is_fallback) {
if (c && c->last_iteration != bus->iteration_counter && c->is_fallback) {
c->last_iteration = bus->iteration_counter;
r = c->callback(bus, 0, m, c->userdata);
if (r != 0)
return r;
......@@ -1631,6 +1674,8 @@ static int process_object(sd_bus *bus, sd_bus_message *m) {
}
}
} while (bus->object_callbacks_modified);
/* We found some handlers but none wanted to take this, then
* return this -- with one exception, we can handle
* introspection minimally ourselves */
......@@ -1750,6 +1795,8 @@ static int process_message(sd_bus *bus, sd_bus_message *m) {
assert(bus);
assert(m);
bus->iteration_counter++;
r = process_hello(bus, m);
if (r != 0)
return r;
......@@ -1995,6 +2042,7 @@ int sd_bus_add_filter(sd_bus *bus, sd_bus_message_handler_t callback, void *user
f->callback = callback;
f->userdata = userdata;
bus->filter_callbacks_modified = true;
LIST_PREPEND(struct filter_callback, callbacks, bus->filter_callbacks, f);
return 0;
}
......@@ -2009,6 +2057,7 @@ int sd_bus_remove_filter(sd_bus *bus, sd_bus_message_handler_t callback, void *u
LIST_FOREACH(callbacks, f, bus->filter_callbacks) {
if (f->callback == callback && f->userdata == userdata) {
bus->filter_callbacks_modified = true;
LIST_REMOVE(struct filter_callback, callbacks, bus->filter_callbacks, f);
free(f);
return 1;
......@@ -2053,6 +2102,7 @@ static int bus_add_object(
c->userdata = userdata;
c->is_fallback = fallback;
bus->object_callbacks_modified = true;
r = hashmap_put(bus->object_callbacks, c->path, c);
if (r < 0) {
free(c->path);
......@@ -2086,6 +2136,7 @@ static int bus_remove_object(
if (c->callback != callback || c->userdata != userdata || c->is_fallback != fallback)
return 0;
bus->object_callbacks_modified = true;
assert_se(c == hashmap_remove(bus->object_callbacks, c->path));
free(c->path);
......@@ -2125,6 +2176,7 @@ int sd_bus_add_match(sd_bus *bus, const char *match, sd_bus_message_handler_t ca
}
if (callback) {
bus->match_callbacks_modified = true;
r = bus_match_add(&bus->match_callbacks, match, callback, userdata, NULL);
if (r < 0) {
......@@ -2147,8 +2199,10 @@ int sd_bus_remove_match(sd_bus *bus, const char *match, sd_bus_message_handler_t
if (bus->bus_client)
r = bus_remove_match_internal(bus, match);
if (callback)
if (callback) {
bus->match_callbacks_modified = true;
q = bus_match_remove(&bus->match_callbacks, match, callback, userdata);
}
if (r < 0)
return r;
......
......@@ -33,8 +33,6 @@ extern "C" {
#endif
/* TODO:
* - allow registration/removl of callbacks from within callbacks
*
* - add page donation logic
* - api for appending/reading fixed arrays
* - merge busctl into systemctl or so?
......
Markdown is supported
0%
or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment