qmp: add 'get-win32-socket'

A process with enough capabilities can duplicate a socket to QEMU. Add a
QMP command to import it and add it to the monitor fd list, so it can be
later used by other commands.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Acked-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20230306122751.2355515-9-marcandre.lureau@redhat.com>

monitor/fds.c

@@ -61,46 +61,55 @@ struct MonFdset {
 static QemuMutex mon_fdsets_lock;
 static QLIST_HEAD(, MonFdset) mon_fdsets;
 
-void qmp_getfd(const char *fdname, Error **errp)
+static bool monitor_add_fd(Monitor *mon, int fd, const char *fdname, Error **errp)
 {
-    Monitor *cur_mon = monitor_cur();
     mon_fd_t *monfd;
-    int fd, tmp_fd;
-
-    fd = qemu_chr_fe_get_msgfd(&cur_mon->chr);
-    if (fd == -1) {
-        error_setg(errp, "No file descriptor supplied via SCM_RIGHTS");
-        return;
-    }
 
     if (qemu_isdigit(fdname[0])) {
         close(fd);
         error_setg(errp, QERR_INVALID_PARAMETER_VALUE, "fdname",
                    "a name not starting with a digit");
-        return;
+        return false;
     }
 
     /* See close() call below. */
-    qemu_mutex_lock(&cur_mon->mon_lock);
-    QLIST_FOREACH(monfd, &cur_mon->fds, next) {
+    qemu_mutex_lock(&mon->mon_lock);
+    QLIST_FOREACH(monfd, &mon->fds, next) {
+        int tmp_fd;
+
         if (strcmp(monfd->name, fdname) != 0) {
             continue;
         }
 
         tmp_fd = monfd->fd;
         monfd->fd = fd;
-        qemu_mutex_unlock(&cur_mon->mon_lock);
+        qemu_mutex_unlock(&mon->mon_lock);
         /* Make sure close() is outside critical section */
         close(tmp_fd);
-        return;
+        return true;
     }
 
     monfd = g_new0(mon_fd_t, 1);
     monfd->name = g_strdup(fdname);
     monfd->fd = fd;
 
-    QLIST_INSERT_HEAD(&cur_mon->fds, monfd, next);
-    qemu_mutex_unlock(&cur_mon->mon_lock);
+    QLIST_INSERT_HEAD(&mon->fds, monfd, next);
+    qemu_mutex_unlock(&mon->mon_lock);
+    return true;
+}
+
+void qmp_getfd(const char *fdname, Error **errp)
+{
+    Monitor *cur_mon = monitor_cur();
+    int fd;
+
+    fd = qemu_chr_fe_get_msgfd(&cur_mon->chr);
+    if (fd == -1) {
+        error_setg(errp, "No file descriptor supplied via SCM_RIGHTS");
+        return;
+    }
+
+    monitor_add_fd(cur_mon, fd, fdname, errp);
 }
 
 void qmp_closefd(const char *fdname, Error **errp)
@@ -214,6 +223,41 @@ AddfdInfo *qmp_add_fd(bool has_fdset_id, int64_t fdset_id,
     return NULL;
 }
 
+#ifdef WIN32
+void qmp_get_win32_socket(const char *infos, const char *fdname, Error **errp)
+{
+    g_autofree WSAPROTOCOL_INFOW *info = NULL;
+    gsize len;
+    SOCKET sk;
+    int fd;
+
+    info = (void *)g_base64_decode(infos, &len);
+    if (len != sizeof(*info)) {
+        error_setg(errp, "Invalid WSAPROTOCOL_INFOW value");
+        return;
+    }
+
+    sk = WSASocketW(FROM_PROTOCOL_INFO,
+                    FROM_PROTOCOL_INFO,
+                    FROM_PROTOCOL_INFO,
+                    info, 0, 0);
+    if (sk == INVALID_SOCKET) {
+        error_setg_win32(errp, WSAGetLastError(), "Couldn't import socket");
+        return;
+    }
+
+    fd = _open_osfhandle(sk, _O_BINARY);
+    if (fd < 0) {
+        error_setg_errno(errp, errno, "Failed to associate a FD with the SOCKET");
+        closesocket(sk);
+        return;
+    }
+
+    monitor_add_fd(monitor_cur(), fd, fdname, errp);
+}
+#endif
+
+
 void qmp_remove_fd(int64_t fdset_id, bool has_fd, int64_t fd, Error **errp)
 {
     MonFdset *mon_fdset;

qapi/misc.json

@@ -275,6 +275,37 @@
 ##
 { 'command': 'getfd', 'data': {'fdname': 'str'} }
 
+##
+# @get-win32-socket:
+#
+# Add a socket that was duplicated to QEMU process with
+# WSADuplicateSocketW() via WSASocket() & WSAPROTOCOL_INFOW structure
+# and assign it a name (the SOCKET is associated with a CRT file
+# descriptor)
+#
+# @info: the WSAPROTOCOL_INFOW structure (encoded in base64)
+#
+# @fdname: file descriptor name
+#
+# Returns: Nothing on success
+#
+# Since: 8.0
+#
+# Notes: If @fdname already exists, the file descriptor assigned to
+#        it will be closed and replaced by the received file
+#        descriptor.
+#
+#        The 'closefd' command can be used to explicitly close the
+#        file descriptor when it is no longer needed.
+#
+# Example:
+#
+# -> { "execute": "get-win32-socket", "arguments": { "info": "abcd123..", fdname": "skclient" } }
+# <- { "return": {} }
+#
+##
+{ 'command': 'get-win32-socket', 'data': {'info': 'str', 'fdname': 'str'}, 'if': 'CONFIG_WIN32' }
+
 ##
 # @closefd:
 #