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-rw-r--r--src/libsystemd-bus/bus-match.c978
1 files changed, 978 insertions, 0 deletions
diff --git a/src/libsystemd-bus/bus-match.c b/src/libsystemd-bus/bus-match.c
new file mode 100644
index 0000000000..ff1edfaaed
--- /dev/null
+++ b/src/libsystemd-bus/bus-match.c
@@ -0,0 +1,978 @@
+/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
+
+/***
+ This file is part of systemd.
+
+ Copyright 2013 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 "bus-internal.h"
+#include "bus-message.h"
+#include "bus-match.h"
+
+/* Example:
+ *
+ * A: type=signal,sender=foo,interface=bar
+ * B: type=signal,sender=quux,interface=fips
+ * C: type=signal,sender=quux,interface=waldo
+ * D: type=signal,member=test
+ * E: sender=miau
+ * F: type=signal
+ * G: type=signal
+ *
+ * results in this tree:
+ *
+ * BUS_MATCH_ROOT
+ * + BUS_MATCH_MESSAGE_TYPE
+ * | ` BUS_MATCH_VALUE: value == signal
+ * | + DBUS_MATCH_SENDER
+ * | | + BUS_MATCH_VALUE: value == foo
+ * | | | ` DBUS_MATCH_INTERFACE
+ * | | | ` BUS_MATCH_VALUE: value == bar
+ * | | | ` BUS_MATCH_LEAF: A
+ * | | ` BUS_MATCH_VALUE: value == quux
+ * | | ` DBUS_MATCH_INTERFACE
+ * | | | BUS_MATCH_VALUE: value == fips
+ * | | | ` BUS_MATCH_LEAF: B
+ * | | ` BUS_MATCH_VALUE: value == waldo
+ * | | ` BUS_MATCH_LEAF: C
+ * | + DBUS_MATCH_MEMBER
+ * | | ` BUS_MATCH_VALUE: value == test
+ * | | ` BUS_MATCH_LEAF: D
+ * | + BUS_MATCH_LEAF: F
+ * | ` BUS_MATCH_LEAF: G
+ * ` BUS_MATCH_SENDER
+ * ` BUS_MATCH_VALUE: value == miau
+ * ` BUS_MATCH_LEAF: E
+ */
+
+static inline bool BUS_MATCH_IS_COMPARE(enum bus_match_node_type t) {
+ return t >= BUS_MATCH_MESSAGE_TYPE && t <= BUS_MATCH_ARG_NAMESPACE_LAST;
+}
+
+static inline bool BUS_MATCH_CAN_HASH(enum bus_match_node_type t) {
+ return (t >= BUS_MATCH_MESSAGE_TYPE && t <= BUS_MATCH_PATH) ||
+ (t >= BUS_MATCH_ARG && t <= BUS_MATCH_ARG_LAST);
+}
+
+static void bus_match_node_free(struct bus_match_node *node) {
+ assert(node);
+ assert(node->parent);
+ assert(!node->child);
+ assert(node->type != BUS_MATCH_ROOT);
+ assert(node->type < _BUS_MATCH_NODE_TYPE_MAX);
+
+ if (node->parent->child) {
+ /* We are apparently linked into the parent's child
+ * list. Let's remove us from there. */
+ if (node->prev) {
+ assert(node->prev->next == node);
+ node->prev->next = node->next;
+ } else {
+ assert(node->parent->child == node);
+ node->parent->child = node->next;
+ }
+
+ if (node->next)
+ node->next->prev = node->prev;
+ }
+
+ if (node->type == BUS_MATCH_VALUE) {
+ /* We might be in the parent's hash table, so clean
+ * this up */
+
+ if (node->parent->type == BUS_MATCH_MESSAGE_TYPE)
+ hashmap_remove(node->parent->compare.children, UINT_TO_PTR(node->value.u8));
+ else if (BUS_MATCH_CAN_HASH(node->parent->type) && node->value.str)
+ hashmap_remove(node->parent->compare.children, node->value.str);
+
+ free(node->value.str);
+ }
+
+ if (BUS_MATCH_IS_COMPARE(node->type)) {
+ assert(hashmap_isempty(node->compare.children));
+ hashmap_free(node->compare.children);
+ }
+
+ free(node);
+}
+
+static bool bus_match_node_maybe_free(struct bus_match_node *node) {
+ assert(node);
+
+ if (node->child)
+ return false;
+
+ if (BUS_MATCH_IS_COMPARE(node->type) && !hashmap_isempty(node->compare.children))
+ return true;
+
+ bus_match_node_free(node);
+ return true;
+}
+
+static bool value_node_test(
+ struct bus_match_node *node,
+ enum bus_match_node_type parent_type,
+ uint8_t value_u8,
+ const char *value_str) {
+
+ assert(node);
+ assert(node->type == BUS_MATCH_VALUE);
+
+ /* Tests parameters against this value node, doing prefix
+ * magic and stuff. */
+
+ switch (parent_type) {
+
+ case BUS_MATCH_MESSAGE_TYPE:
+ return node->value.u8 == value_u8;
+
+ case BUS_MATCH_SENDER:
+ case BUS_MATCH_DESTINATION:
+ case BUS_MATCH_INTERFACE:
+ case BUS_MATCH_MEMBER:
+ case BUS_MATCH_PATH:
+ case BUS_MATCH_ARG ... BUS_MATCH_ARG_LAST:
+ return streq(node->value.str, value_str);
+
+ case BUS_MATCH_ARG_NAMESPACE ... BUS_MATCH_ARG_NAMESPACE_LAST:
+ return namespace_simple_pattern(node->value.str, value_str);
+
+ case BUS_MATCH_PATH_NAMESPACE:
+ return path_simple_pattern(node->value.str, value_str);
+
+ case BUS_MATCH_ARG_PATH ... BUS_MATCH_ARG_PATH_LAST:
+ return path_complex_pattern(node->value.str, value_str);
+
+ default:
+ assert_not_reached("Invalid node type");
+ }
+}
+
+static bool value_node_same(
+ struct bus_match_node *node,
+ enum bus_match_node_type parent_type,
+ uint8_t value_u8,
+ const char *value_str) {
+
+ /* Tests parameters against this value node, not doing prefix
+ * magic and stuff, i.e. this one actually compares the match
+ * itself.*/
+
+ assert(node);
+ assert(node->type == BUS_MATCH_VALUE);
+
+ switch (parent_type) {
+
+ case BUS_MATCH_MESSAGE_TYPE:
+ return node->value.u8 == value_u8;
+
+ case BUS_MATCH_SENDER:
+ case BUS_MATCH_DESTINATION:
+ case BUS_MATCH_INTERFACE:
+ case BUS_MATCH_MEMBER:
+ case BUS_MATCH_PATH:
+ case BUS_MATCH_ARG ... BUS_MATCH_ARG_LAST:
+ case BUS_MATCH_ARG_NAMESPACE ... BUS_MATCH_ARG_NAMESPACE_LAST:
+ case BUS_MATCH_PATH_NAMESPACE:
+ case BUS_MATCH_ARG_PATH ... BUS_MATCH_ARG_PATH_LAST:
+ return streq(node->value.str, value_str);
+
+ default:
+ assert_not_reached("Invalid node type");
+ }
+}
+
+int bus_match_run(
+ sd_bus *bus,
+ struct bus_match_node *node,
+ int ret,
+ sd_bus_message *m) {
+
+
+ const char *test_str = NULL;
+ uint8_t test_u8 = 0;
+ int r;
+
+ assert(m);
+
+ if (!node)
+ 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
+ * exceptions here though, which are BUS_NODE_ROOT (which
+ * cannot have a sibling), and BUS_NODE_VALUE (whose siblings
+ * are invoked anyway by its parent. */
+
+ switch (node->type) {
+
+ case BUS_MATCH_ROOT:
+
+ /* Run all children. Since we cannot have any siblings
+ * we won't call any. The children of the root node
+ * are compares or leaves, they will automatically
+ * call their siblings. */
+ return bus_match_run(bus, node->child, ret, m);
+
+ case BUS_MATCH_VALUE:
+
+ /* Run all children. We don't execute any siblings, we
+ * assume our caller does that. The children of value
+ * nodes are compares or leaves, they will
+ * automatically call their siblings */
+
+ assert(node->child);
+ return bus_match_run(bus, node->child, ret, m);
+
+ case BUS_MATCH_LEAF:
+
+ /* Run the callback. And then invoke siblings. */
+ assert(node->leaf.callback);
+ r = node->leaf.callback(bus, ret, m, node->leaf.userdata);
+ if (r != 0)
+ return r;
+
+ return bus_match_run(bus, node->next, ret, m);
+
+ case BUS_MATCH_MESSAGE_TYPE:
+ test_u8 = m->header->type;
+ break;
+
+ case BUS_MATCH_SENDER:
+ test_str = m->sender;
+ /* FIXME: resolve test_str from a well-known to a unique name first */
+ break;
+
+ case BUS_MATCH_DESTINATION:
+ test_str = m->destination;
+ break;
+
+ case BUS_MATCH_INTERFACE:
+ test_str = m->interface;
+ break;
+
+ case BUS_MATCH_MEMBER:
+ test_str = m->member;
+ break;
+
+ case BUS_MATCH_PATH:
+ case BUS_MATCH_PATH_NAMESPACE:
+ test_str = m->path;
+ break;
+
+ case BUS_MATCH_ARG ... BUS_MATCH_ARG_LAST:
+ test_str = bus_message_get_arg(m, node->type - BUS_MATCH_ARG);
+ break;
+
+ case BUS_MATCH_ARG_PATH ... BUS_MATCH_ARG_PATH_LAST:
+ test_str = bus_message_get_arg(m, node->type - BUS_MATCH_ARG_PATH);
+ break;
+
+ case BUS_MATCH_ARG_NAMESPACE ... BUS_MATCH_ARG_NAMESPACE_LAST:
+ test_str = bus_message_get_arg(m, node->type - BUS_MATCH_ARG_NAMESPACE);
+ break;
+
+ default:
+ assert_not_reached("Unknown match type.");
+ }
+
+ if (BUS_MATCH_CAN_HASH(node->type)) {
+ struct bus_match_node *found;
+
+ /* Lookup via hash table, nice! So let's jump directly. */
+
+ if (test_str)
+ found = hashmap_get(node->compare.children, test_str);
+ else if (node->type == BUS_MATCH_MESSAGE_TYPE)
+ found = hashmap_get(node->compare.children, UINT_TO_PTR(test_u8));
+ else
+ found = NULL;
+
+ if (found) {
+ r = bus_match_run(bus, found, ret, m);
+ if (r != 0)
+ return r;
+ }
+ } else {
+ struct bus_match_node *c;
+
+ /* No hash table, so let's iterate manually... */
+
+ for (c = node->child; c; c = c->next) {
+ if (!value_node_test(c, node->type, test_u8, test_str))
+ continue;
+
+ r = bus_match_run(bus, c, ret, m);
+ if (r != 0)
+ return r;
+ }
+ }
+
+ /* And now, let's invoke our siblings */
+ return bus_match_run(bus, node->next, ret, m);
+}
+
+static int bus_match_add_compare_value(
+ struct bus_match_node *where,
+ enum bus_match_node_type t,
+ uint8_t value_u8,
+ const char *value_str,
+ struct bus_match_node **ret) {
+
+ struct bus_match_node *c = NULL, *n = NULL;
+ int r;
+
+ assert(where);
+ assert(where->type == BUS_MATCH_ROOT || where->type == BUS_MATCH_VALUE);
+ assert(BUS_MATCH_IS_COMPARE(t));
+ assert(ret);
+
+ for (c = where->child; c && c->type != t; c = c->next)
+ ;
+
+ if (c) {
+ /* Comparison node already exists? Then let's see if
+ * the value node exists too. */
+
+ if (t == BUS_MATCH_MESSAGE_TYPE)
+ n = hashmap_get(c->compare.children, UINT_TO_PTR(value_u8));
+ else if (BUS_MATCH_CAN_HASH(t))
+ n = hashmap_get(c->compare.children, value_str);
+ else {
+ for (n = c->child; n && !value_node_same(n, t, value_u8, value_str); n = n->next)
+ ;
+ }
+
+ if (n) {
+ *ret = n;
+ return 0;
+ }
+ } else {
+ /* Comparison node, doesn't exist yet? Then let's
+ * create it. */
+
+ c = new0(struct bus_match_node, 1);
+ if (!c) {
+ r = -ENOMEM;
+ goto fail;
+ }
+
+ c->type = t;
+ c->parent = where;
+ c->next = where->child;
+ if (c->next)
+ c->next->prev = c;
+ where->child = c;
+
+ if (t == BUS_MATCH_MESSAGE_TYPE) {
+ c->compare.children = hashmap_new(trivial_hash_func, trivial_compare_func);
+ if (!c->compare.children) {
+ r = -ENOMEM;
+ goto fail;
+ }
+ } else if (BUS_MATCH_CAN_HASH(t)) {
+ c->compare.children = hashmap_new(string_hash_func, string_compare_func);
+ if (!c->compare.children) {
+ r = -ENOMEM;
+ goto fail;
+ }
+ }
+ }
+
+ n = new0(struct bus_match_node, 1);
+ if (!n) {
+ r = -ENOMEM;
+ goto fail;
+ }
+
+ n->type = BUS_MATCH_VALUE;
+ n->value.u8 = value_u8;
+ if (value_str) {
+ n->value.str = strdup(value_str);
+ if (!n->value.str) {
+ r = -ENOMEM;
+ goto fail;
+ }
+ }
+
+ n->parent = c;
+ if (c->compare.children) {
+
+ if (t == BUS_MATCH_MESSAGE_TYPE)
+ r = hashmap_put(c->compare.children, UINT_TO_PTR(value_u8), n);
+ else
+ r = hashmap_put(c->compare.children, n->value.str, n);
+
+ if (r < 0)
+ goto fail;
+ } else {
+ n->next = c->child;
+ if (n->next)
+ n->next->prev = n;
+ c->child = n;
+ }
+
+ *ret = n;
+ return 1;
+
+fail:
+ if (c)
+ bus_match_node_maybe_free(c);
+
+ if (n) {
+ free(n->value.str);
+ free(n);
+ }
+
+ return r;
+}
+
+static int bus_match_find_compare_value(
+ struct bus_match_node *where,
+ enum bus_match_node_type t,
+ uint8_t value_u8,
+ const char *value_str,
+ struct bus_match_node **ret) {
+
+ struct bus_match_node *c, *n;
+
+ assert(where);
+ assert(where->type == BUS_MATCH_ROOT || where->type == BUS_MATCH_VALUE);
+ assert(BUS_MATCH_IS_COMPARE(t));
+ assert(ret);
+
+ for (c = where->child; c && c->type != t; c = c->next)
+ ;
+
+ if (!c)
+ return 0;
+
+ if (t == BUS_MATCH_MESSAGE_TYPE)
+ n = hashmap_get(c->compare.children, UINT_TO_PTR(value_u8));
+ else if (BUS_MATCH_CAN_HASH(t))
+ n = hashmap_get(c->compare.children, value_str);
+ else {
+ for (n = c->child; !value_node_same(n, t, value_u8, value_str); n = n->next)
+ ;
+ }
+
+ if (n) {
+ *ret = n;
+ return 1;
+ }
+
+ return 0;
+}
+
+static int bus_match_add_leaf(
+ struct bus_match_node *where,
+ sd_message_handler_t callback,
+ void *userdata,
+ struct bus_match_node **ret) {
+
+ struct bus_match_node *n;
+
+ assert(where);
+ assert(where->type == BUS_MATCH_ROOT || where->type == BUS_MATCH_VALUE);
+ assert(ret);
+
+ n = new0(struct bus_match_node, 1);
+ if (!n)
+ return -ENOMEM;
+
+ n->type = BUS_MATCH_LEAF;
+ n->parent = where;
+ n->next = where->child;
+ if (n->next)
+ n->next->prev = n;
+ n->leaf.callback = callback;
+ n->leaf.userdata = userdata;
+
+ where->child = n;
+
+ *ret = n;
+ return 1;
+}
+
+static int bus_match_find_leaf(
+ struct bus_match_node *where,
+ sd_message_handler_t callback,
+ void *userdata,
+ struct bus_match_node **ret) {
+
+ struct bus_match_node *c;
+
+ assert(where);
+ assert(where->type == BUS_MATCH_ROOT || where->type == BUS_MATCH_VALUE);
+ assert(ret);
+
+ for (c = where->child; c; c = c->next) {
+ if (c->type == BUS_MATCH_LEAF &&
+ c->leaf.callback == callback &&
+ c->leaf.userdata == userdata) {
+ *ret = c;
+ return 1;
+ }
+ }
+
+ return 0;
+}
+
+enum bus_match_node_type bus_match_node_type_from_string(const char *k, size_t n) {
+ assert(k);
+
+ if (n == 4 && memcmp(k, "type", 4) == 0)
+ return BUS_MATCH_MESSAGE_TYPE;
+ if (n == 6 && memcmp(k, "sender", 6) == 0)
+ return BUS_MATCH_SENDER;
+ if (n == 11 && memcmp(k, "destination", 11) == 0)
+ return BUS_MATCH_DESTINATION;
+ if (n == 9 && memcmp(k, "interface", 9) == 0)
+ return BUS_MATCH_INTERFACE;
+ if (n == 6 && memcmp(k, "member", 6) == 0)
+ return BUS_MATCH_MEMBER;
+ if (n == 4 && memcmp(k, "path", 4) == 0)
+ return BUS_MATCH_PATH;
+ if (n == 14 && memcmp(k, "path_namespace", 14) == 0)
+ return BUS_MATCH_PATH_NAMESPACE;
+
+ if (n == 4 && memcmp(k, "arg", 3) == 0) {
+ int j;
+
+ j = undecchar(k[3]);
+ if (j < 0)
+ return -EINVAL;
+
+ return BUS_MATCH_ARG + j;
+ }
+
+ if (n == 5 && memcmp(k, "arg", 3) == 0) {
+ int a, b;
+ enum bus_match_node_type t;
+
+ a = undecchar(k[3]);
+ b = undecchar(k[4]);
+ if (a <= 0 || b < 0)
+ return -EINVAL;
+
+ t = BUS_MATCH_ARG + a * 10 + b;
+ if (t > BUS_MATCH_ARG_LAST)
+ return -EINVAL;
+
+ return t;
+ }
+
+ if (n == 8 && memcmp(k, "arg", 3) == 0 && memcmp(k + 4, "path", 4) == 0) {
+ int j;
+
+ j = undecchar(k[3]);
+ if (j < 0)
+ return -EINVAL;
+
+ return BUS_MATCH_ARG_PATH + j;
+ }
+
+ if (n == 9 && memcmp(k, "arg", 3) == 0 && memcmp(k + 5, "path", 4) == 0) {
+ enum bus_match_node_type t;
+ int a, b;
+
+ a = undecchar(k[3]);
+ b = undecchar(k[4]);
+ if (a <= 0 || b < 0)
+ return -EINVAL;
+
+ t = BUS_MATCH_ARG_PATH + a * 10 + b;
+ if (t > BUS_MATCH_ARG_PATH_LAST)
+ return -EINVAL;
+
+ return t;
+ }
+
+ if (n == 13 && memcmp(k, "arg", 3) == 0 && memcmp(k + 4, "namespace", 9) == 0) {
+ int j;
+
+ j = undecchar(k[3]);
+ if (j < 0)
+ return -EINVAL;
+
+ return BUS_MATCH_ARG_NAMESPACE + j;
+ }
+
+ if (n == 14 && memcmp(k, "arg", 3) == 0 && memcmp(k + 5, "namespace", 9) == 0) {
+ enum bus_match_node_type t;
+ int a, b;
+
+ a = undecchar(k[3]);
+ b = undecchar(k[4]);
+ if (a <= 0 || b < 0)
+ return -EINVAL;
+
+ t = BUS_MATCH_ARG_NAMESPACE + a * 10 + b;
+ if (t > BUS_MATCH_ARG_NAMESPACE_LAST)
+ return -EINVAL;
+
+ return t;
+ }
+
+ return -EINVAL;
+}
+
+struct match_component {
+ enum bus_match_node_type type;
+ uint8_t value_u8;
+ char *value_str;
+};
+
+static int match_component_compare(const void *a, const void *b) {
+ const struct match_component *x = a, *y = b;
+
+ if (x->type < y->type)
+ return -1;
+ if (x->type > y->type)
+ return 1;
+
+ return 0;
+}
+
+static void free_components(struct match_component *components, unsigned n_components) {
+ unsigned i;
+
+ for (i = 0; i < n_components; i++)
+ free(components[i].value_str);
+
+ free(components);
+}
+
+static int parse_match(
+ const char *match,
+ struct match_component **_components,
+ unsigned *_n_components) {
+
+ const char *p = match;
+ struct match_component *components = NULL;
+ size_t components_allocated = 0;
+ unsigned n_components = 0, i;
+ _cleanup_free_ char *value = NULL;
+ int r;
+
+ assert(match);
+ assert(_components);
+ assert(_n_components);
+
+ while (*p != 0) {
+ const char *eq, *q;
+ enum bus_match_node_type t;
+ unsigned j = 0;
+ size_t value_allocated = 0;
+ bool escaped = false;
+ uint8_t u;
+
+ eq = strchr(p, '=');
+ if (!eq)
+ return -EINVAL;
+
+ if (eq[1] != '\'')
+ return -EINVAL;
+
+ t = bus_match_node_type_from_string(p, eq - p);
+ if (t < 0)
+ return -EINVAL;
+
+ for (q = eq + 2;; q++) {
+
+ if (*q == 0) {
+ r = -EINVAL;
+ goto fail;
+ }
+
+ if (!escaped) {
+ if (*q == '\\') {
+ escaped = true;
+ continue;
+ }
+ if (*q == '\'') {
+ if (value)
+ value[j] = 0;
+ break;
+ }
+ }
+
+ if (!greedy_realloc((void**) &value, &value_allocated, j + 2)) {
+ r = -ENOMEM;
+ goto fail;
+ }
+
+ value[j++] = *q;
+ escaped = false;
+ }
+
+ if (t == BUS_MATCH_MESSAGE_TYPE) {
+ r = bus_message_type_from_string(value, &u);
+ if (r < 0)
+ goto fail;
+
+ free(value);
+ value = NULL;
+ } else
+ u = 0;
+
+ if (!greedy_realloc((void**) &components, &components_allocated,
+ (n_components + 1) * sizeof(struct match_component))) {
+ r = -ENOMEM;
+ goto fail;
+ }
+
+ components[n_components].type = t;
+ components[n_components].value_str = value;
+ components[n_components].value_u8 = u;
+ n_components++;
+
+ value = NULL;
+
+ if (q[1] == 0)
+ break;
+
+ if (q[1] != ',') {
+ r = -EINVAL;
+ goto fail;
+ }
+
+ p = q + 2;
+ }
+
+ /* Order the whole thing, so that we always generate the same tree */
+ qsort(components, n_components, sizeof(struct match_component), match_component_compare);
+
+ /* Check for duplicates */
+ for (i = 0; i+1 < n_components; i++)
+ if (components[i].type == components[i+1].type) {
+ r = -EINVAL;
+ goto fail;
+ }
+
+ *_components = components;
+ *_n_components = n_components;
+
+ return 0;
+
+fail:
+ free_components(components, n_components);
+ return r;
+}
+
+int bus_match_add(
+ struct bus_match_node *root,
+ const char *match,
+ sd_message_handler_t callback,
+ void *userdata,
+ struct bus_match_node **ret) {
+
+ struct match_component *components = NULL;
+ unsigned n_components = 0, i;
+ struct bus_match_node *n;
+ int r;
+
+ assert(root);
+ assert(match);
+ assert(callback);
+
+ r = parse_match(match, &components, &n_components);
+ if (r < 0)
+ return r;
+
+ n = root;
+ for (i = 0; i < n_components; i++) {
+ r = bus_match_add_compare_value(
+ n, components[i].type,
+ components[i].value_u8, components[i].value_str, &n);
+ if (r < 0)
+ goto finish;
+ }
+
+ r = bus_match_add_leaf(n, callback, userdata, &n);
+ if (r < 0)
+ goto finish;
+
+ if (ret)
+ *ret = n;
+
+finish:
+ free_components(components, n_components);
+ return r;
+}
+
+int bus_match_remove(
+ struct bus_match_node *root,
+ const char *match,
+ sd_message_handler_t callback,
+ void *userdata) {
+
+ struct match_component *components = NULL;
+ unsigned n_components = 0, i;
+ struct bus_match_node *n, **gc;
+ int r;
+
+ assert(root);
+ assert(match);
+
+ r = parse_match(match, &components, &n_components);
+ if (r < 0)
+ return r;
+
+ gc = newa(struct bus_match_node*, n_components);
+
+ n = root;
+ for (i = 0; i < n_components; i++) {
+ r = bus_match_find_compare_value(
+ n, components[i].type,
+ components[i].value_u8, components[i].value_str,
+ &n);
+ if (r <= 0)
+ goto finish;
+
+ gc[i] = n;
+ }
+
+ r = bus_match_find_leaf(n, callback, userdata, &n);
+ if (r <= 0)
+ goto finish;
+
+ /* Free the leaf */
+ bus_match_node_free(n);
+
+ /* Prune the tree above */
+ for (i = n_components; i > 0; i --) {
+ struct bus_match_node *p = gc[i-1]->parent;
+
+ if (!bus_match_node_maybe_free(gc[i-1]))
+ break;
+
+ if (!bus_match_node_maybe_free(p))
+ break;
+ }
+
+finish:
+ free_components(components, n_components);
+ return r;
+}
+
+void bus_match_free(struct bus_match_node *node) {
+ struct bus_match_node *c;
+
+ if (!node)
+ return;
+
+ if (BUS_MATCH_CAN_HASH(node->type)) {
+ Iterator i;
+
+ HASHMAP_FOREACH(c, node->compare.children, i)
+ bus_match_free(c);
+
+ assert(hashmap_isempty(node->compare.children));
+ }
+
+ while ((c = node->child))
+ bus_match_free(c);
+
+ if (node->type != BUS_MATCH_ROOT)
+ bus_match_node_free(node);
+}
+
+const char* bus_match_node_type_to_string(enum bus_match_node_type t, char buf[], size_t l) {
+ switch (t) {
+
+ case BUS_MATCH_ROOT:
+ return "root";
+
+ case BUS_MATCH_VALUE:
+ return "value";
+
+ case BUS_MATCH_LEAF:
+ return "leaf";
+
+ case BUS_MATCH_MESSAGE_TYPE:
+ return "type";
+
+ case BUS_MATCH_SENDER:
+ return "sender";
+
+ case BUS_MATCH_DESTINATION:
+ return "destination";
+
+ case BUS_MATCH_INTERFACE:
+ return "interface";
+
+ case BUS_MATCH_MEMBER:
+ return "member";
+
+ case BUS_MATCH_PATH:
+ return "path";
+
+ case BUS_MATCH_PATH_NAMESPACE:
+ return "path_namespace";
+
+ case BUS_MATCH_ARG ... BUS_MATCH_ARG_LAST:
+ snprintf(buf, l, "arg%i", t - BUS_MATCH_ARG);
+ return buf;
+
+ case BUS_MATCH_ARG_PATH ... BUS_MATCH_ARG_PATH_LAST:
+ snprintf(buf, l, "arg%ipath", t - BUS_MATCH_ARG_PATH);
+ return buf;
+
+ case BUS_MATCH_ARG_NAMESPACE ... BUS_MATCH_ARG_NAMESPACE_LAST:
+ snprintf(buf, l, "arg%inamespace", t - BUS_MATCH_ARG_NAMESPACE);
+ return buf;
+
+ default:
+ return NULL;
+ }
+}
+
+void bus_match_dump(struct bus_match_node *node, unsigned level) {
+ struct bus_match_node *c;
+ _cleanup_free_ char *pfx = NULL;
+ char buf[32];
+
+ if (!node)
+ return;
+
+ pfx = strrep(" ", level);
+ printf("%s[%s]", strempty(pfx), bus_match_node_type_to_string(node->type, buf, sizeof(buf)));
+
+ if (node->type == BUS_MATCH_VALUE) {
+ if (node->parent->type == BUS_MATCH_MESSAGE_TYPE)
+ printf(" <%u>\n", node->value.u8);
+ else
+ printf(" <%s>\n", node->value.str);
+ } else if (node->type == BUS_MATCH_ROOT)
+ puts(" root");
+ else if (node->type == BUS_MATCH_LEAF)
+ printf(" %p/%p\n", node->leaf.callback, node->leaf.userdata);
+ else
+ putchar('\n');
+
+ if (BUS_MATCH_CAN_HASH(node->type)) {
+ Iterator i;
+
+ HASHMAP_FOREACH(c, node->compare.children, i)
+ bus_match_dump(c, level + 1);
+ }
+
+ for (c = node->child; c; c = c->next)
+ bus_match_dump(c, level + 1);
+}