From 91b14d6ff362b938a72db17b095ee9903d07381b Mon Sep 17 00:00:00 2001 From: Tom Gundersen Date: Wed, 24 Jun 2015 18:41:46 +0200 Subject: resolved: reference count the dns servers We want to reference the servers from their active transactions, so make sure they stay around as long as the transaction does. --- src/resolve/resolved-dns-server.c | 44 ++++++++++++++++++++++++++------------- src/resolve/resolved-dns-server.h | 5 ++++- src/resolve/resolved-link.c | 23 +++++++++++++------- src/resolve/resolved-manager.c | 32 +++++++++++++++++++++------- 4 files changed, 73 insertions(+), 31 deletions(-) diff --git a/src/resolve/resolved-dns-server.c b/src/resolve/resolved-dns-server.c index 9a62a63258..92e48ae442 100644 --- a/src/resolve/resolved-dns-server.c +++ b/src/resolve/resolved-dns-server.c @@ -41,6 +41,7 @@ int dns_server_new( if (!s) return -ENOMEM; + s->n_ref = 1; s->type = type; s->family = family; s->address = *in_addr; @@ -74,33 +75,46 @@ int dns_server_new( return 0; } -DnsServer* dns_server_free(DnsServer *s) { +DnsServer* dns_server_ref(DnsServer *s) { if (!s) return NULL; - if (s->link) { - if (s->type == DNS_SERVER_LINK) - LIST_REMOVE(servers, s->link->dns_servers, s); + assert(s->n_ref > 0); - if (s->link->current_dns_server == s) - link_set_dns_server(s->link, NULL); - } + s->n_ref ++; - if (s->manager) { - if (s->type == DNS_SERVER_SYSTEM) - LIST_REMOVE(servers, s->manager->dns_servers, s); - else if (s->type == DNS_SERVER_FALLBACK) - LIST_REMOVE(servers, s->manager->fallback_dns_servers, s); + return s; +} + +static DnsServer* dns_server_free(DnsServer *s) { + if (!s) + return NULL; - if (s->manager->current_dns_server == s) - manager_set_dns_server(s->manager, NULL); - } + if (s->link && s->link->current_dns_server == s) + link_set_dns_server(s->link, NULL); + + if (s->manager && s->manager->current_dns_server == s) + manager_set_dns_server(s->manager, NULL); free(s); return NULL; } +DnsServer* dns_server_unref(DnsServer *s) { + if (!s) + return NULL; + + assert(s->n_ref > 0); + + if (s->n_ref == 1) + dns_server_free(s); + else + s->n_ref --; + + return NULL; +} + static unsigned long dns_server_hash_func(const void *p, const uint8_t hash_key[HASH_KEY_SIZE]) { const DnsServer *s = p; uint64_t u; diff --git a/src/resolve/resolved-dns-server.h b/src/resolve/resolved-dns-server.h index 70ff35b08f..03013beb82 100644 --- a/src/resolve/resolved-dns-server.h +++ b/src/resolve/resolved-dns-server.h @@ -37,6 +37,8 @@ typedef enum DnsServerType { struct DnsServer { Manager *manager; + unsigned n_ref; + DnsServerType type; Link *link; @@ -57,6 +59,7 @@ int dns_server_new( int family, const union in_addr_union *address); -DnsServer* dns_server_free(DnsServer *s); +DnsServer* dns_server_ref(DnsServer *s); +DnsServer* dns_server_unref(DnsServer *s); extern const struct hash_ops dns_server_hash_ops; diff --git a/src/resolve/resolved-link.c b/src/resolve/resolved-link.c index ff8dc3a5bc..d66b3a88fc 100644 --- a/src/resolve/resolved-link.c +++ b/src/resolve/resolved-link.c @@ -58,7 +58,6 @@ int link_new(Manager *m, Link **ret, int ifindex) { } Link *link_free(Link *l) { - if (!l) return NULL; @@ -68,8 +67,12 @@ Link *link_free(Link *l) { if (l->manager) hashmap_remove(l->manager->links, INT_TO_PTR(l->ifindex)); - while (l->dns_servers) - dns_server_free(l->dns_servers); + while (l->dns_servers) { + DnsServer *s = l->dns_servers; + + LIST_REMOVE(servers, l->dns_servers, s); + dns_server_unref(s); + } dns_scope_free(l->unicast_scope); dns_scope_free(l->llmnr_ipv4_scope); @@ -182,14 +185,20 @@ static int link_update_dns_servers(Link *l) { } LIST_FOREACH_SAFE(servers, s, nx, l->dns_servers) - if (s->marked) - dns_server_free(s); + if (s->marked) { + LIST_REMOVE(servers, l->dns_servers, s); + dns_server_unref(s); + } return 0; clear: - while (l->dns_servers) - dns_server_free(l->dns_servers); + while (l->dns_servers) { + s = l->dns_servers; + + LIST_REMOVE(servers, l->dns_servers, s); + dns_server_unref(s); + } return r; } diff --git a/src/resolve/resolved-manager.c b/src/resolve/resolved-manager.c index 6785a2e3c7..e050092a12 100644 --- a/src/resolve/resolved-manager.c +++ b/src/resolve/resolved-manager.c @@ -603,8 +603,10 @@ int manager_read_resolv_conf(Manager *m) { } LIST_FOREACH_SAFE(servers, s, nx, m->dns_servers) - if (s->marked) - dns_server_free(s); + if (s->marked) { + LIST_REMOVE(servers, m->dns_servers, s); + dns_server_unref(s); + } /* Whenever /etc/resolv.conf changes, start using the first * DNS server of it. This is useful to deal with broken @@ -619,8 +621,12 @@ int manager_read_resolv_conf(Manager *m) { return 0; clear: - while (m->dns_servers) - dns_server_free(m->dns_servers); + while (m->dns_servers) { + s = m->dns_servers; + + LIST_REMOVE(servers, m->dns_servers, s); + dns_server_unref(s); + } return r; } @@ -1381,15 +1387,25 @@ void manager_verify_all(Manager *m) { } void manager_flush_dns_servers(Manager *m, DnsServerType t) { + DnsServer *s; + assert(m); if (t == DNS_SERVER_SYSTEM) - while (m->dns_servers) - dns_server_free(m->dns_servers); + while (m->dns_servers) { + s = m->dns_servers; + + LIST_REMOVE(servers, m->dns_servers, s); + dns_server_unref(s); + } if (t == DNS_SERVER_FALLBACK) - while (m->fallback_dns_servers) - dns_server_free(m->fallback_dns_servers); + while (m->fallback_dns_servers) { + s = m->fallback_dns_servers; + + LIST_REMOVE(servers, m->fallback_dns_servers, s); + dns_server_unref(s); + } } static const char* const support_table[_SUPPORT_MAX] = { -- cgit v1.2.3-54-g00ecf