[PATCH 7/7] spice: Call qemu spice functions indirectly

[Christophe de Dinechin <dinechin@redhat.com>]

In order to be able to move all of spice in a shared library that is
loaded dynamically only on demand, this commit puts the functions
called by the main binary in a QemuSpiceOps structure, and use static
inline stubs to preserve the call sites.

With these changes, the following shared libraries are no longer
necessary in the top-level qemu binary when building with CONFIG_MDULES:

        libspice-server.so.1 => /lib64/libspice-server.so.1 (HEX)
        libopus.so.0 => /lib64/libopus.so.0 (HEX)
        liblz4.so.1 => /lib64/liblz4.so.1 (HEX)
        libgstapp-1.0.so.0 => /lib64/libgstapp-1.0.so.0 (HEX)
        libgstvideo-1.0.so.0 => /lib64/libgstvideo-1.0.so.0 (HEX)
        libgstbase-1.0.so.0 => /lib64/libgstbase-1.0.so.0 (HEX)
        libgstreamer-1.0.so.0 => /lib64/libgstreamer-1.0.so.0 (HEX)
        libssl.so.1.1 => /lib64/libssl.so.1.1 (HEX)
        liborc-0.4.so.0 => /lib64/liborc-0.4.so.0 (HEX)

Signed-off-by: Christophe de Dinechin <dinechin@redhat.com>
---
 include/ui/qemu-spice.h | 74 +++++++++++++++++++----------------------
 monitor/hmp-cmds.c      | 13 ++++++++
 monitor/misc.c          |  2 +-
 monitor/qmp-cmds.c      |  6 ++--
 softmmu/vl.c            | 28 ++++++++++++++--
 ui/spice-core.c         | 33 ++++++++++++++++--
 6 files changed, 107 insertions(+), 49 deletions(-)

diff --git a/include/ui/qemu-spice.h b/include/ui/qemu-spice.h
index d34cea2e0f..9721d8817e 100644
--- a/include/ui/qemu-spice.h
+++ b/include/ui/qemu-spice.h
@@ -25,21 +25,28 @@
 #include <spice.h>
 #include "qemu/config-file.h"
 
-extern int using_spice;
+#define using_spice     (qemu_spice.in_use())
 
-void qemu_spice_init(void);
 void qemu_spice_input_init(void);
 void qemu_spice_audio_init(void);
-void qemu_spice_display_init(void);
-int qemu_spice_display_add_client(int csock, int skipauth, int tls);
 int qemu_spice_add_interface(SpiceBaseInstance *sin);
 bool qemu_spice_have_display_interface(QemuConsole *con);
 int qemu_spice_add_display_interface(QXLInstance *qxlin, QemuConsole *con);
+
+#if !defined(CONFIG_MODULES) || defined(BUILD_DSO)
+bool qemu_is_using_spice(void);
+void qemu_start_using_spice(void);
+void qemu_spice_init(void);
+void qemu_spice_display_init(void);
+int qemu_spice_display_add_client(int csock, int skipauth, int tls);
 int qemu_spice_set_passwd(const char *passwd,
                           bool fail_if_connected, bool disconnect_if_connected);
 int qemu_spice_set_pw_expire(time_t expires);
 int qemu_spice_migrate_info(const char *hostname, int port, int tls_port,
                             const char *subject);
+struct SpiceInfo *qemu_spice_query(Error **errp);
+#endif /* !CONFIG_MODULES || BUILD_DSO */
+
 
 #if !defined(SPICE_SERVER_VERSION) || (SPICE_SERVER_VERSION < 0xc06)
 #define SPICE_NEEDS_SET_MM_TIME 1
@@ -47,46 +54,33 @@ int qemu_spice_migrate_info(const char *hostname, int port, int tls_port,
 #define SPICE_NEEDS_SET_MM_TIME 0
 #endif
 
-#else  /* CONFIG_SPICE */
-
-#include "qemu/error-report.h"
-
-#define using_spice 0
-#define spice_displays 0
-static inline int qemu_spice_set_passwd(const char *passwd,
-                                        bool fail_if_connected,
-                                        bool disconnect_if_connected)
-{
-    return -1;
-}
-static inline int qemu_spice_set_pw_expire(time_t expires)
-{
-    return -1;
-}
-static inline int qemu_spice_migrate_info(const char *h, int p, int t,
-                                          const char *s)
-{
-    return -1;
-}
+#else /* !CONFIG_SPICE */
 
-static inline int qemu_spice_display_add_client(int csock, int skipauth,
-                                                int tls)
-{
-    return -1;
-}
+#define using_spice     0
 
-static inline void qemu_spice_display_init(void)
-{
-    /* This must never be called if CONFIG_SPICE is disabled */
-    error_report("spice support is disabled");
-    abort();
-}
+#endif /* CONFIG_SPICE */
 
-static inline void qemu_spice_init(void)
+/* Module high-level inteface for SPICE */
+struct QemuSpiceOps
 {
-}
-
-#endif /* CONFIG_SPICE */
+    bool (*in_use)(void);
+    void (*init)(void);
+    void (*display_init)(void);
+    int (*display_add_client)(int csock, int skipauth, int tls);
+
+    int (*set_passwd)(const char *passwd,
+                      bool fail_if_connected,
+                      bool disconnect_if_connected);
+    int (*set_pw_expire)(time_t expires);
+    int (*migrate_info)(const char *hostname,
+                        int port, int tls_port,
+                        const char *subject);
+    struct SpiceInfo * (*query)(Error **errp);
+};
+typedef struct QemuSpiceOps QemuSpiceOps;
+void qemu_spice_ops_register(QemuSpiceOps *ops);
+
+extern struct QemuSpiceOps qemu_spice;
 
 static inline bool qemu_using_spice(Error **errp)
 {
diff --git a/monitor/hmp-cmds.c b/monitor/hmp-cmds.c
index ae4b6a4246..8e10af188f 100644
--- a/monitor/hmp-cmds.c
+++ b/monitor/hmp-cmds.c
@@ -57,6 +57,7 @@
 
 #ifdef CONFIG_SPICE
 #include <spice/enums.h>
+#include "ui/qemu-spice.h"
 #endif
 
 void hmp_handle_error(Monitor *mon, Error *err)
@@ -573,6 +574,14 @@ void hmp_info_vnc(Monitor *mon, const QDict *qdict)
 #endif
 
 #ifdef CONFIG_SPICE
+SpiceInfo *qmp_query_spice(Error **errp)
+{
+    if (!using_spice) {
+        return NULL;
+    }
+    return qemu_spice.query(errp);
+}
+
 void hmp_info_spice(Monitor *mon, const QDict *qdict)
 {
     SpiceChannelList *chan;
@@ -599,6 +608,10 @@ void hmp_info_spice(Monitor *mon, const QDict *qdict)
 
     info = qmp_query_spice(NULL);
 
+    if (!info) {
+        monitor_printf(mon, "Server: not started\n");
+        goto out;
+    }
     if (!info->enabled) {
         monitor_printf(mon, "Server: disabled\n");
         goto out;
diff --git a/monitor/misc.c b/monitor/misc.c
index e847b58a8c..88f8915734 100644
--- a/monitor/misc.c
+++ b/monitor/misc.c
@@ -443,7 +443,7 @@ void qmp_client_migrate_info(const char *protocol, const char *hostname,
             return;
         }
 
-        if (qemu_spice_migrate_info(hostname,
+        if (qemu_spice.migrate_info(hostname,
                                     has_port ? port : -1,
                                     has_tls_port ? tls_port : -1,
                                     cert_subject)) {
diff --git a/monitor/qmp-cmds.c b/monitor/qmp-cmds.c
index 864cbfa32e..9f9822b3f3 100644
--- a/monitor/qmp-cmds.c
+++ b/monitor/qmp-cmds.c
@@ -196,7 +196,7 @@ void qmp_set_password(const char *protocol, const char *password,
         if (!qemu_using_spice(errp)) {
             return;
         }
-        rc = qemu_spice_set_passwd(password, fail_if_connected,
+        rc = qemu_spice.set_passwd(password, fail_if_connected,
                                    disconnect_if_connected);
         if (rc != 0) {
             error_setg(errp, QERR_SET_PASSWD_FAILED);
@@ -242,7 +242,7 @@ void qmp_expire_password(const char *protocol, const char *whenstr,
         if (!qemu_using_spice(errp)) {
             return;
         }
-        rc = qemu_spice_set_pw_expire(when);
+        rc = qemu_spice.set_pw_expire(when);
         if (rc != 0) {
             error_setg(errp, QERR_SET_PASSWD_FAILED);
         }
@@ -339,7 +339,7 @@ void qmp_add_client(const char *protocol, const char *fdname,
         }
         skipauth = has_skipauth ? skipauth : false;
         tls = has_tls ? tls : false;
-        if (qemu_spice_display_add_client(fd, skipauth, tls) < 0) {
+        if (qemu_spice.display_add_client(fd, skipauth, tls) < 0) {
             error_setg(errp, "spice failed to add client");
             close(fd);
         }
diff --git a/softmmu/vl.c b/softmmu/vl.c
index bc0dcc4f58..8defda56c9 100644
--- a/softmmu/vl.c
+++ b/softmmu/vl.c
@@ -173,6 +173,30 @@ int icount_align_option;
 QemuUUID qemu_uuid;
 bool qemu_uuid_set;
 
+static bool qemu_is_not_using_spice(void)
+{
+    return 0;
+}
+
+static void qemu_spice_init_no_op(void)
+{
+}
+
+/*
+ * Only two fields are initialized, that can be used even when SPICE
+ * is not configured or not loaded. Other functions are protected by
+ * checking if using_spice.
+ */
+QemuSpiceOps qemu_spice = {
+    .in_use             = qemu_is_not_using_spice,
+    .init               = qemu_spice_init_no_op,
+};
+
+void qemu_spice_ops_register(QemuSpiceOps *ops)
+{
+    memcpy(&qemu_spice, ops, sizeof(qemu_spice));
+}
+
 static NotifierList exit_notifiers =
     NOTIFIER_LIST_INITIALIZER(exit_notifiers);
 
@@ -4128,7 +4152,7 @@ void qemu_init(int argc, char **argv, char **envp)
     /* spice needs the timers to be initialized by this point */
     /* spice must initialize before audio as it changes the default auiodev */
     /* spice must initialize before chardevs (for spicevmc and spiceport) */
-    qemu_spice_init();
+    qemu_spice.init();
 
     qemu_opts_foreach(qemu_find_opts("object"),
                       user_creatable_add_opts_foreach,
@@ -4424,7 +4448,7 @@ void qemu_init(int argc, char **argv, char **envp)
 #endif
 
     if (using_spice) {
-        qemu_spice_display_init();
+        qemu_spice.display_init();
     }
 
     if (foreach_device_config(DEV_GDB, gdbserver_start) < 0) {
diff --git a/ui/spice-core.c b/ui/spice-core.c
index 37dd68f2ab..9d7ac70d92 100644
--- a/ui/spice-core.c
+++ b/ui/spice-core.c
@@ -48,7 +48,7 @@ static time_t auth_expires = TIME_MAX;
 static int spice_migration_completed;
 static int spice_display_is_running;
 static int spice_have_target_host;
-int using_spice = 0;
+static int is_using_spice;
 
 static QemuThread me;
 
@@ -503,7 +503,7 @@ static QemuOptsList qemu_spice_opts = {
     },
 };
 
-SpiceInfo *qmp_query_spice(Error **errp)
+SpiceInfo *qemu_spice_query(Error **errp)
 {
     QemuOpts *opts = QTAILQ_FIRST(&qemu_spice_opts.head);
     int port, tls_port;
@@ -634,6 +634,16 @@ static void vm_change_state_handler(void *opaque, int running,
     }
 }
 
+bool qemu_is_using_spice(void)
+{
+    return is_using_spice;
+}
+
+void qemu_start_using_spice(void)
+{
+    is_using_spice = 1;
+}
+
 void qemu_spice_init(void)
 {
     QemuOpts *opts = QTAILQ_FIRST(&qemu_spice_opts.head);
@@ -796,7 +806,7 @@ void qemu_spice_init(void)
         error_report("failed to initialize spice server");
         exit(1);
     };
-    using_spice = 1;
+    qemu_start_using_spice();
 
     migration_state.notify = migration_state_notifier;
     add_migration_state_change_notifier(&migration_state);
@@ -1000,3 +1010,20 @@ static void spice_register_config(void)
     qemu_add_opts(&qemu_spice_opts);
 }
 opts_init(spice_register_config);
+
+static QemuSpiceOps qemu_spice_ops = {
+    .in_use             = qemu_is_using_spice,
+    .init               = qemu_spice_init,
+    .display_init       = qemu_spice_display_init,
+    .display_add_client = qemu_spice_display_add_client,
+    .set_passwd         = qemu_spice_set_passwd,
+    .set_pw_expire      = qemu_spice_set_pw_expire,
+    .migrate_info       = qemu_spice_migrate_info,
+    .query              = qemu_spice_query,
+};
+
+static void spice_register_ops(void)
+{
+    qemu_spice_ops_register(&qemu_spice_ops);
+}
+type_init(spice_register_ops);
-- 
2.26.2