qemu-sockets: add socket_listen, socket_connect, socket_parse

These are QAPI-friendly versions of the qemu-sockets functions.  They
support IP sockets, Unix sockets, and named file descriptors, using a
QAPI union to dispatch to the correct function.

Reviewed-by: Luiz Capitulino <lcapitulino@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Makefile

@@ -161,7 +161,7 @@ qemu-img.o: qemu-img-cmds.h
 
 tools-obj-y = $(oslib-obj-y) $(trace-obj-y) qemu-tool.o qemu-timer.o \
 	qemu-timer-common.o main-loop.o notify.o \
-	iohandler.o cutils.o iov.o async.o
+	iohandler.o cutils.o iov.o async.o error.o
 tools-obj-$(CONFIG_POSIX) += compatfd.o
 
 qemu-img$(EXESUF): qemu-img.o $(tools-obj-y) $(block-obj-y)

qemu-sockets.c

@@ -22,6 +22,7 @@
 #include <errno.h>
 #include <unistd.h>
 
+#include "monitor.h"
 #include "qemu_socket.h"
 #include "qemu-common.h" /* for qemu_isdigit */
 #include "main-loop.h"
@@ -845,6 +846,104 @@ int unix_nonblocking_connect(const char *path,
     return sock;
 }
 
+SocketAddress *socket_parse(const char *str, Error **errp)
+{
+    SocketAddress *addr = NULL;
+
+    addr = g_new(SocketAddress, 1);
+    if (strstart(str, "unix:", NULL)) {
+        if (str[5] == '\0') {
+            error_setg(errp, "invalid Unix socket address\n");
+            goto fail;
+        } else {
+            addr->kind = SOCKET_ADDRESS_KIND_UNIX;
+            addr->q_unix = g_new(UnixSocketAddress, 1);
+            addr->q_unix->path = g_strdup(str + 5);
+        }
+    } else if (strstart(str, "fd:", NULL)) {
+        if (str[3] == '\0') {
+            error_setg(errp, "invalid file descriptor address\n");
+            goto fail;
+        } else {
+            addr->kind = SOCKET_ADDRESS_KIND_FD;
+            addr->fd = g_new(String, 1);
+            addr->fd->str = g_strdup(str + 3);
+        }
+    } else {
+        addr->kind = SOCKET_ADDRESS_KIND_INET;
+        addr->inet = g_new(InetSocketAddress, 1);
+        addr->inet = inet_parse(str, errp);
+        if (addr->inet == NULL) {
+            goto fail;
+        }
+    }
+    return addr;
+
+fail:
+    qapi_free_SocketAddress(addr);
+    return NULL;
+}
+
+int socket_connect(SocketAddress *addr, Error **errp,
+                   NonBlockingConnectHandler *callback, void *opaque)
+{
+    QemuOpts *opts;
+    int fd;
+
+    opts = qemu_opts_create(&dummy_opts, NULL, 0, NULL);
+    switch (addr->kind) {
+    case SOCKET_ADDRESS_KIND_INET:
+        inet_addr_to_opts(opts, addr->inet);
+        fd = inet_connect_opts(opts, errp, callback, opaque);
+        break;
+
+    case SOCKET_ADDRESS_KIND_UNIX:
+        qemu_opt_set(opts, "path", addr->q_unix->path);
+        fd = unix_connect_opts(opts, errp, callback, opaque);
+        break;
+
+    case SOCKET_ADDRESS_KIND_FD:
+        fd = monitor_get_fd(cur_mon, addr->fd->str, errp);
+        if (callback) {
+            callback(fd, opaque);
+        }
+        break;
+
+    default:
+        abort();
+    }
+    qemu_opts_del(opts);
+    return fd;
+}
+
+int socket_listen(SocketAddress *addr, Error **errp)
+{
+    QemuOpts *opts;
+    int fd;
+
+    opts = qemu_opts_create(&dummy_opts, NULL, 0, NULL);
+    switch (addr->kind) {
+    case SOCKET_ADDRESS_KIND_INET:
+        inet_addr_to_opts(opts, addr->inet);
+        fd = inet_listen_opts(opts, 0, errp);
+        break;
+
+    case SOCKET_ADDRESS_KIND_UNIX:
+        qemu_opt_set(opts, "path", addr->q_unix->path);
+        fd = unix_listen_opts(opts, errp);
+        break;
+
+    case SOCKET_ADDRESS_KIND_FD:
+        fd = monitor_get_fd(cur_mon, addr->fd->str, errp);
+        break;
+
+    default:
+        abort();
+    }
+    qemu_opts_del(opts);
+    return fd;
+}
+
 #ifdef _WIN32
 static void socket_cleanup(void)
 {

qemu-tool.c

@@ -38,6 +38,12 @@ const char *qemu_get_vm_name(void)
 
 Monitor *cur_mon;
 
+int monitor_get_fd(Monitor *mon, const char *name, Error **errp)
+{
+    error_setg(errp, "only QEMU supports file descriptor passing");
+    return -1;
+}
+
 void vm_stop(RunState state)
 {
     abort();

qemu_socket.h

@@ -65,6 +65,11 @@ int unix_nonblocking_connect(const char *str,
                              NonBlockingConnectHandler *callback,
                              void *opaque, Error **errp);
 
+SocketAddress *socket_parse(const char *str, Error **errp);
+int socket_connect(SocketAddress *addr, Error **errp,
+                   NonBlockingConnectHandler *callback, void *opaque);
+int socket_listen(SocketAddress *addr, Error **errp);
+
 /* Old, ipv4 only bits.  Don't use for new code. */
 int parse_host_port(struct sockaddr_in *saddr, const char *str);
 int socket_init(void);