char: Factor out qmp_add_client() parts and move to chardev/

Code moves from MAINTAINERS section "QMP" to "Character device
backends".

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20230124121946.1139465-5-armbru@redhat.com>

chardev/char.c

@@ -25,6 +25,7 @@
 #include "qemu/osdep.h"
 #include "qemu/cutils.h"
 #include "monitor/monitor.h"
+#include "monitor/qmp-helpers.h"
 #include "qemu/config-file.h"
 #include "qemu/error-report.h"
 #include "qemu/qemu-print.h"
@@ -1166,6 +1167,25 @@ void qmp_chardev_send_break(const char *id, Error **errp)
     qemu_chr_be_event(chr, CHR_EVENT_BREAK);
 }
 
+bool qmp_add_client_char(int fd, bool has_skipauth, bool skipauth,
+                         bool has_tls, bool tls, const char *protocol,
+                         Error **errp)
+{
+    Chardev *s = qemu_chr_find(protocol);
+
+    if (!s) {
+        error_setg(errp, "protocol '%s' is invalid", protocol);
+        close(fd);
+        return false;
+    }
+    if (qemu_chr_add_client(s, fd) < 0) {
+        error_setg(errp, "failed to add client");
+        close(fd);
+        return false;
+    }
+    return true;
+}
+
 /*
  * Add a timeout callback for the chardev (in milliseconds), return
  * the GSource object created. Please use this to add timeout hook for

include/monitor/qmp-helpers.h

@@ -22,5 +22,8 @@ bool qmp_add_client_vnc(int fd, bool has_skipauth, bool skipauth,
 bool qmp_add_client_dbus_display(int fd, bool has_skipauth, bool skipauth,
                         bool has_tls, bool tls, Error **errp);
 #endif
+bool qmp_add_client_char(int fd, bool has_skipauth, bool skipauth,
+                         bool has_tls, bool tls, const char *protocol,
+                         Error **errp);
 
 #endif

monitor/qmp-cmds.c

@@ -17,7 +17,6 @@
 #include "monitor/monitor.h"
 #include "monitor/qmp-helpers.h"
 #include "sysemu/sysemu.h"
-#include "chardev/char.h"
 #include "sysemu/kvm.h"
 #include "sysemu/runstate.h"
 #include "sysemu/runstate-action.h"
@@ -174,7 +173,6 @@ void qmp_add_client(const char *protocol, const char *fdname,
         { "@dbus-display", qmp_add_client_dbus_display },
 #endif
     };
-    Chardev *s;
     int fd, i;
 
     fd = monitor_get_fd(monitor_cur(), fdname, errp);
@@ -192,16 +190,9 @@ void qmp_add_client(const char *protocol, const char *fdname,
         }
     }
 
-    s = qemu_chr_find(protocol);
-    if (!s) {
-        error_setg(errp, "protocol '%s' is invalid", protocol);
+    if (!qmp_add_client_char(fd, has_skipauth, skipauth, has_tls, tls,
+                             protocol, errp)) {
         close(fd);
-        return;
-    }
-    if (qemu_chr_add_client(s, fd) < 0) {
-        error_setg(errp, "failed to add client");
-        close(fd);
-        return;
     }
 }