/*-*- 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 . ***/ #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_ptr(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, sd_bus_message *m) { const char *test_str = NULL; uint8_t test_u8 = 0; int r; assert(m); 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 * 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, 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, m); case BUS_MATCH_LEAF: if (bus) { if (node->leaf.last_iteration == bus->iteration_counter) return 0; node->leaf.last_iteration = bus->iteration_counter; } r = sd_bus_message_rewind(m, true); if (r < 0) return r; /* Run the callback. And then invoke siblings. */ assert(node->leaf.callback); r = node->leaf.callback(bus, m, node->leaf.userdata); if (r != 0) return r; return bus_match_run(bus, node->next, 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, 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, m); if (r != 0) return r; } } if (bus && bus->match_callbacks_modified) return 0; /* And now, let's invoke our siblings */ return bus_match_run(bus, node->next, 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_bus_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_bus_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(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(components, components_allocated, n_components + 1)) { 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_bus_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_bus_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); }