qemu/io/dns-resolver.c
Peter Xu a17536c594 qio: non-default context for threaded qtask
qio_task_run_in_thread() allows main thread to run blocking operations
in the background. However it has an assumption on that it's always
working with the default context. This patch tries to allow the threaded
QIO task framework to run with non-default gcontext.

Currently no functional change so far, so the QIOTasks are still always
running on main context.

Reviewed-by: Daniel P. Berrange <berrange@redhat.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
2018-03-06 10:19:05 +00:00

280 lines
7.9 KiB
C

/*
* QEMU DNS resolver
*
* Copyright (c) 2016 Red Hat, Inc.
*
* This library 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 of the License, or (at your option) any later version.
*
* This library 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 this library; if not, see <http://www.gnu.org/licenses/>.
*
*/
#include "qemu/osdep.h"
#include "io/dns-resolver.h"
#include "qapi/clone-visitor.h"
#include "qapi/qapi-visit-sockets.h"
#include "qemu/sockets.h"
#include "qapi/error.h"
#include "qemu/cutils.h"
#ifndef AI_NUMERICSERV
# define AI_NUMERICSERV 0
#endif
static QIODNSResolver *instance;
static GOnce instance_init = G_ONCE_INIT;
static gpointer qio_dns_resolve_init_instance(gpointer unused G_GNUC_UNUSED)
{
instance = QIO_DNS_RESOLVER(object_new(TYPE_QIO_DNS_RESOLVER));
return NULL;
}
QIODNSResolver *qio_dns_resolver_get_instance(void)
{
g_once(&instance_init, qio_dns_resolve_init_instance, NULL);
return instance;
}
static int qio_dns_resolver_lookup_sync_inet(QIODNSResolver *resolver,
SocketAddress *addr,
size_t *naddrs,
SocketAddress ***addrs,
Error **errp)
{
struct addrinfo ai, *res, *e;
InetSocketAddress *iaddr = &addr->u.inet;
char port[33];
char uaddr[INET6_ADDRSTRLEN + 1];
char uport[33];
int rc;
Error *err = NULL;
size_t i;
*naddrs = 0;
*addrs = NULL;
memset(&ai, 0, sizeof(ai));
ai.ai_flags = AI_PASSIVE;
if (iaddr->has_numeric && iaddr->numeric) {
ai.ai_flags |= AI_NUMERICHOST | AI_NUMERICSERV;
}
ai.ai_family = inet_ai_family_from_address(iaddr, &err);
ai.ai_socktype = SOCK_STREAM;
if (err) {
error_propagate(errp, err);
return -1;
}
if (iaddr->host == NULL) {
error_setg(errp, "host not specified");
return -1;
}
if (iaddr->port != NULL) {
pstrcpy(port, sizeof(port), iaddr->port);
} else {
port[0] = '\0';
}
rc = getaddrinfo(strlen(iaddr->host) ? iaddr->host : NULL,
strlen(port) ? port : NULL, &ai, &res);
if (rc != 0) {
error_setg(errp, "address resolution failed for %s:%s: %s",
iaddr->host, port, gai_strerror(rc));
return -1;
}
for (e = res; e != NULL; e = e->ai_next) {
(*naddrs)++;
}
*addrs = g_new0(SocketAddress *, *naddrs);
/* create socket + bind */
for (i = 0, e = res; e != NULL; i++, e = e->ai_next) {
SocketAddress *newaddr = g_new0(SocketAddress, 1);
newaddr->type = SOCKET_ADDRESS_TYPE_INET;
getnameinfo((struct sockaddr *)e->ai_addr, e->ai_addrlen,
uaddr, INET6_ADDRSTRLEN, uport, 32,
NI_NUMERICHOST | NI_NUMERICSERV);
newaddr->u.inet = (InetSocketAddress){
.host = g_strdup(uaddr),
.port = g_strdup(uport),
.has_numeric = true,
.numeric = true,
.has_to = iaddr->has_to,
.to = iaddr->to,
.has_ipv4 = iaddr->has_ipv4,
.ipv4 = iaddr->ipv4,
.has_ipv6 = iaddr->has_ipv6,
.ipv6 = iaddr->ipv6,
};
(*addrs)[i] = newaddr;
}
freeaddrinfo(res);
return 0;
}
static int qio_dns_resolver_lookup_sync_nop(QIODNSResolver *resolver,
SocketAddress *addr,
size_t *naddrs,
SocketAddress ***addrs,
Error **errp)
{
*naddrs = 1;
*addrs = g_new0(SocketAddress *, 1);
(*addrs)[0] = QAPI_CLONE(SocketAddress, addr);
return 0;
}
int qio_dns_resolver_lookup_sync(QIODNSResolver *resolver,
SocketAddress *addr,
size_t *naddrs,
SocketAddress ***addrs,
Error **errp)
{
switch (addr->type) {
case SOCKET_ADDRESS_TYPE_INET:
return qio_dns_resolver_lookup_sync_inet(resolver,
addr,
naddrs,
addrs,
errp);
case SOCKET_ADDRESS_TYPE_UNIX:
case SOCKET_ADDRESS_TYPE_VSOCK:
case SOCKET_ADDRESS_TYPE_FD:
return qio_dns_resolver_lookup_sync_nop(resolver,
addr,
naddrs,
addrs,
errp);
default:
abort();
}
}
struct QIODNSResolverLookupData {
SocketAddress *addr;
SocketAddress **addrs;
size_t naddrs;
};
static void qio_dns_resolver_lookup_data_free(gpointer opaque)
{
struct QIODNSResolverLookupData *data = opaque;
size_t i;
qapi_free_SocketAddress(data->addr);
for (i = 0; i < data->naddrs; i++) {
qapi_free_SocketAddress(data->addrs[i]);
}
g_free(data->addrs);
g_free(data);
}
static void qio_dns_resolver_lookup_worker(QIOTask *task,
gpointer opaque)
{
QIODNSResolver *resolver = QIO_DNS_RESOLVER(qio_task_get_source(task));
struct QIODNSResolverLookupData *data = opaque;
Error *err = NULL;
qio_dns_resolver_lookup_sync(resolver,
data->addr,
&data->naddrs,
&data->addrs,
&err);
if (err) {
qio_task_set_error(task, err);
} else {
qio_task_set_result_pointer(task, opaque, NULL);
}
object_unref(OBJECT(resolver));
}
void qio_dns_resolver_lookup_async(QIODNSResolver *resolver,
SocketAddress *addr,
QIOTaskFunc func,
gpointer opaque,
GDestroyNotify notify)
{
QIOTask *task;
struct QIODNSResolverLookupData *data =
g_new0(struct QIODNSResolverLookupData, 1);
data->addr = QAPI_CLONE(SocketAddress, addr);
task = qio_task_new(OBJECT(resolver), func, opaque, notify);
qio_task_run_in_thread(task,
qio_dns_resolver_lookup_worker,
data,
qio_dns_resolver_lookup_data_free,
NULL);
}
void qio_dns_resolver_lookup_result(QIODNSResolver *resolver,
QIOTask *task,
size_t *naddrs,
SocketAddress ***addrs)
{
struct QIODNSResolverLookupData *data =
qio_task_get_result_pointer(task);
size_t i;
*naddrs = 0;
*addrs = NULL;
if (!data) {
return;
}
*naddrs = data->naddrs;
*addrs = g_new0(SocketAddress *, data->naddrs);
for (i = 0; i < data->naddrs; i++) {
(*addrs)[i] = QAPI_CLONE(SocketAddress, data->addrs[i]);
}
}
static const TypeInfo qio_dns_resolver_info = {
.parent = TYPE_OBJECT,
.name = TYPE_QIO_DNS_RESOLVER,
.instance_size = sizeof(QIODNSResolver),
.class_size = sizeof(QIODNSResolverClass),
};
static void qio_dns_resolver_register_types(void)
{
type_register_static(&qio_dns_resolver_info);
}
type_init(qio_dns_resolver_register_types);