Introduce a 'client_add' monitor command accepting an open FD

Allow client connections for VNC and socket based character
devices to be passed in over the monitor using SCM_RIGHTS.

One intended usage scenario is to start QEMU with VNC on a
UNIX domain socket. An unprivileged user which cannot access
the UNIX domain socket, can then connect to QEMU's VNC server
by passing an open FD to libvirt, which passes it onto QEMU.

 { "execute": "get_fd", "arguments": { "fdname": "myclient" } }
 { "return": {} }
 { "execute": "add_client", "arguments": { "protocol": "vnc",
                                           "fdname": "myclient",
                                           "skipauth": true } }
 { "return": {} }

In this case 'protocol' can be 'vnc' or 'spice', or the name
of a character device (eg from -chardev id=XXXX)

The 'skipauth' parameter can be used to skip any configured
VNC authentication scheme, which is useful if the mgmt layer
talking to the monitor has already authenticated the client
in another way.

* console.h: Define 'vnc_display_add_client' method
* monitor.c: Implement 'client_add' command
* qemu-char.c, qemu-char.h: Add 'qemu_char_add_client' method
* qerror.c, qerror.h: Add QERR_ADD_CLIENT_FAILED
* qmp-commands.hx: Declare 'client_add' command
* ui/vnc.c: Implement 'vnc_display_add_client' method

Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>

diff --git a/console.h b/console.h
index c09537b8618664d59fbb6540f0b9d00e99c783e6..67d137384e152c77f019c7fb141fce2f4646a989 100644 (file)
--- a/console.h
+++ b/console.h
@@ -372,6 +372,7 @@ void cocoa_display_init(DisplayState *ds, int full_screen);
 void vnc_display_init(DisplayState *ds);
 void vnc_display_close(DisplayState *ds);
 int vnc_display_open(DisplayState *ds, const char *display);
+void vnc_display_add_client(DisplayState *ds, int csock, int skipauth);
 int vnc_display_disable_login(DisplayState *ds);
 char *vnc_display_local_addr(DisplayState *ds);
 #ifdef CONFIG_VNC

diff --git a/monitor.c b/monitor.c
index 67ceb46a620eb219415dab9971b22f3352af5ca9..718935b881349be6e398e3e9fc1c1df177851618 100644 (file)
--- a/monitor.c
+++ b/monitor.c
@@ -1185,6 +1185,38 @@ static int expire_password(Monitor *mon, const QDict *qdict, QObject **ret_data)
     return -1;
 }
 
+static int add_graphics_client(Monitor *mon, const QDict *qdict, QObject **ret_data)
+{
+    const char *protocol  = qdict_get_str(qdict, "protocol");
+    const char *fdname = qdict_get_str(qdict, "fdname");
+    int skipauth = qdict_get_try_bool(qdict, "skipauth", 0);
+    CharDriverState *s;
+
+    if (strcmp(protocol, "spice") == 0) {
+        if (!using_spice) {
+            /* correct one? spice isn't a device ,,, */
+            qerror_report(QERR_DEVICE_NOT_ACTIVE, "spice");
+            return -1;
+        }
+       qerror_report(QERR_ADD_CLIENT_FAILED);
+       return -1;
+    } else if (strcmp(protocol, "vnc") == 0) {
+       int fd = monitor_get_fd(mon, fdname);
+       vnc_display_add_client(NULL, fd, skipauth);
+       return 0;
+    } else if ((s = qemu_chr_find(protocol)) != NULL) {
+       int fd = monitor_get_fd(mon, fdname);
+       if (qemu_chr_add_client(s, fd) < 0) {
+           qerror_report(QERR_ADD_CLIENT_FAILED);
+           return -1;
+       }
+       return 0;
+    }
+
+    qerror_report(QERR_INVALID_PARAMETER, "protocol");
+    return -1;
+}
+
 static int client_migrate_info(Monitor *mon, const QDict *qdict, QObject **ret_data)
 {
     const char *protocol = qdict_get_str(qdict, "protocol");

diff --git a/qemu-char.c b/qemu-char.c
index 926987b98ada1029317c55fd1bb76ec8dfdf6c11..dcf706592b3db8da21b1ba66d3bfb271fb5d0466 100644 (file)
--- a/qemu-char.c
+++ b/qemu-char.c
@@ -168,6 +168,11 @@ int qemu_chr_get_msgfd(CharDriverState *s)
     return s->get_msgfd ? s->get_msgfd(s) : -1;
 }
 
+int qemu_chr_add_client(CharDriverState *s, int fd)
+{
+    return s->chr_add_client ? s->chr_add_client(s, fd) : -1;
+}
+
 void qemu_chr_accept_input(CharDriverState *s)
 {
     if (s->chr_accept_input)
@@ -2146,6 +2151,22 @@ static void socket_set_nodelay(int fd)
     setsockopt(fd, IPPROTO_TCP, TCP_NODELAY, (char *)&val, sizeof(val));
 }
 
+static int tcp_chr_add_client(CharDriverState *chr, int fd)
+{
+    TCPCharDriver *s = chr->opaque;
+    if (s->fd != -1)
+       return -1;
+
+    socket_set_nonblock(fd);
+    if (s->do_nodelay)
+        socket_set_nodelay(fd);
+    s->fd = fd;
+    qemu_set_fd_handler(s->listen_fd, NULL, NULL, NULL);
+    tcp_chr_connect(chr);
+
+    return 0;
+}
+
 static void tcp_chr_accept(void *opaque)
 {
     CharDriverState *chr = opaque;
@@ -2178,12 +2199,8 @@ static void tcp_chr_accept(void *opaque)
             break;
         }
     }
-    socket_set_nonblock(fd);
-    if (s->do_nodelay)
-        socket_set_nodelay(fd);
-    s->fd = fd;
-    qemu_set_fd_handler(s->listen_fd, NULL, NULL, NULL);
-    tcp_chr_connect(chr);
+    if (tcp_chr_add_client(chr, fd) < 0)
+       close(fd);
 }
 
 static void tcp_chr_close(CharDriverState *chr)
@@ -2256,6 +2273,7 @@ static int qemu_chr_open_socket(QemuOpts *opts, CharDriverState **_chr)
     chr->chr_write = tcp_chr_write;
     chr->chr_close = tcp_chr_close;
     chr->get_msgfd = tcp_get_msgfd;
+    chr->chr_add_client = tcp_chr_add_client;
 
     if (is_listen) {
         s->listen_fd = fd;

diff --git a/qemu-char.h b/qemu-char.h
index 892c6da9aa153dc1f348ef7ad1c83840af744da8..f361c6d281f13dec65d6aa23c7642cb26d1bc288 100644 (file)
--- a/qemu-char.h
+++ b/qemu-char.h
@@ -57,6 +57,7 @@ struct CharDriverState {
     void (*chr_update_read_handler)(struct CharDriverState *s);
     int (*chr_ioctl)(struct CharDriverState *s, int cmd, void *arg);
     int (*get_msgfd)(struct CharDriverState *s);
+    int (*chr_add_client)(struct CharDriverState *chr, int fd);
     IOEventHandler *chr_event;
     IOCanReadHandler *chr_can_read;
     IOReadHandler *chr_read;
@@ -99,6 +100,7 @@ int qemu_chr_can_read(CharDriverState *s);
 void qemu_chr_read(CharDriverState *s, uint8_t *buf, int len);
 int qemu_chr_get_msgfd(CharDriverState *s);
 void qemu_chr_accept_input(CharDriverState *s);
+int qemu_chr_add_client(CharDriverState *s, int fd);
 void qemu_chr_info_print(Monitor *mon, const QObject *ret_data);
 void qemu_chr_info(Monitor *mon, QObject **ret_data);
 CharDriverState *qemu_chr_find(const char *name);

diff --git a/qerror.c b/qerror.c
index 229d0d63e3fb98c76c93d74a9e29d8cac8015c03..69c1bc9af746aaef64491f33b291540c7aa40c7d 100644 (file)
--- a/qerror.c
+++ b/qerror.c
@@ -197,6 +197,10 @@ static const QErrorStringTable qerror_table[] = {
         .error_fmt = QERR_SET_PASSWD_FAILED,
         .desc      = "Could not set password",
     },
+    {
+        .error_fmt = QERR_ADD_CLIENT_FAILED,
+        .desc      = "Could not add client",
+    },
     {
         .error_fmt = QERR_TOO_MANY_FILES,
         .desc      = "Too many open files",

diff --git a/qerror.h b/qerror.h
index 7ec0fc12d7663e5543e411e74ae10149582e06e8..8058456d2e831ffbb15a019849d0e53b16adceda 100644 (file)
--- a/qerror.h
+++ b/qerror.h
@@ -166,6 +166,9 @@ QError *qobject_to_qerror(const QObject *obj);
 #define QERR_SET_PASSWD_FAILED \
     "{ 'class': 'SetPasswdFailed', 'data': {} }"
 
+#define QERR_ADD_CLIENT_FAILED \
+    "{ 'class': 'AddClientFailed', 'data': {} }"
+
 #define QERR_TOO_MANY_FILES \
     "{ 'class': 'TooManyFiles', 'data': {} }"
 

diff --git a/qmp-commands.hx b/qmp-commands.hx
index 5d44edf4e78005b00c19642e4e5f20f70f037a1f..54e313ce52e3501e902ad8e874129f8f87091dfb 100644 (file)
--- a/qmp-commands.hx
+++ b/qmp-commands.hx
@@ -918,6 +918,33 @@ Example:
 
 EQMP
 
+    {
+        .name       = "add_client",
+        .args_type  = "protocol:s,fdname:s,skipauth:b?",
+        .params     = "protocol fdname skipauth",
+        .help       = "add a graphics client",
+        .user_print = monitor_user_noop,
+        .mhandler.cmd_new = add_graphics_client,
+    },
+
+SQMP
+add_client
+----------
+
+Add a graphics client
+
+Arguments:
+
+- "protocol": protocol name (json-string)
+- "fdname": file descriptor name (json-string)
+
+Example:
+
+-> { "execute": "add_client", "arguments": { "protocol": "vnc",
+                                             "fdname": "myclient" } }
+<- { "return": {} }
+
+EQMP
     {
         .name       = "qmp_capabilities",
         .args_type  = "",

diff --git a/ui/vnc.c b/ui/vnc.c
index 39b5b51fa9699df598d87d356fe092d0cff5d8be..8602adc68b83001bd1c9f5a2bcd4ed2d2ded3d80 100644 (file)
--- a/ui/vnc.c
+++ b/ui/vnc.c
@@ -2924,3 +2924,10 @@ int vnc_display_open(DisplayState *ds, const char *display)
     }
     return qemu_set_fd_handler2(vs->lsock, NULL, vnc_listen_read, NULL, vs);
 }
+
+void vnc_display_add_client(DisplayState *ds, int csock, int skipauth)
+{
+    VncDisplay *vs = ds ? (VncDisplay *)ds->opaque : vnc_display;
+
+    return vnc_connect(vs, csock, skipauth);
+}