qapi: Convert change

Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>

blockdev.c

@@ -717,8 +717,31 @@ void qmp_block_passwd(const char *device, const char *password, Error **errp)
     }
 }
 
-int do_change_block(Monitor *mon, const char *device,
-                    const char *filename, const char *fmt)
+static void qmp_bdrv_open_encrypted(BlockDriverState *bs, const char *filename,
+                                    int bdrv_flags, BlockDriver *drv,
+                                    const char *password, Error **errp)
+{
+    if (bdrv_open(bs, filename, bdrv_flags, drv) < 0) {
+        error_set(errp, QERR_OPEN_FILE_FAILED, filename);
+        return;
+    }
+
+    if (bdrv_key_required(bs)) {
+        if (password) {
+            if (bdrv_set_key(bs, password) < 0) {
+                error_set(errp, QERR_INVALID_PASSWORD);
+            }
+        } else {
+            error_set(errp, QERR_DEVICE_ENCRYPTED, bdrv_get_device_name(bs),
+                      bdrv_get_encrypted_filename(bs));
+        }
+    } else if (password) {
+        error_set(errp, QERR_DEVICE_NOT_ENCRYPTED, bdrv_get_device_name(bs));
+    }
+}
+
+void qmp_change_blockdev(const char *device, const char *filename,
+                         bool has_format, const char *format, Error **errp)
 {
     BlockDriverState *bs;
     BlockDriver *drv = NULL;
@@ -727,29 +750,28 @@ int do_change_block(Monitor *mon, const char *device,
 
     bs = bdrv_find(device);
     if (!bs) {
-        qerror_report(QERR_DEVICE_NOT_FOUND, device);
-        return -1;
+        error_set(errp, QERR_DEVICE_NOT_FOUND, device);
+        return;
     }
-    if (fmt) {
-        drv = bdrv_find_whitelisted_format(fmt);
+
+    if (format) {
+        drv = bdrv_find_whitelisted_format(format);
         if (!drv) {
-            qerror_report(QERR_INVALID_BLOCK_FORMAT, fmt);
-            return -1;
+            error_set(errp, QERR_INVALID_BLOCK_FORMAT, format);
+            return;
         }
     }
+
     eject_device(bs, 0, &err);
     if (error_is_set(&err)) {
-        qerror_report_err(err);
-        error_free(err);
-        return -1;
+        error_propagate(errp, err);
+        return;
     }
+
     bdrv_flags = bdrv_is_read_only(bs) ? 0 : BDRV_O_RDWR;
     bdrv_flags |= bdrv_is_snapshot(bs) ? BDRV_O_SNAPSHOT : 0;
-    if (bdrv_open(bs, filename, bdrv_flags, drv) < 0) {
-        qerror_report(QERR_OPEN_FILE_FAILED, filename);
-        return -1;
-    }
-    return monitor_read_bdrv_key_start(mon, bs, NULL, NULL);
+
+    qmp_bdrv_open_encrypted(bs, filename, bdrv_flags, drv, NULL, errp);
 }
 
 /* throttling disk I/O limits */

blockdev.h

@@ -11,6 +11,7 @@
 #define BLOCKDEV_H
 
 #include "block.h"
+#include "error.h"
 #include "qemu-queue.h"
 
 void blockdev_mark_auto_del(BlockDriverState *bs);
@@ -57,9 +58,9 @@ DriveInfo *drive_init(QemuOpts *arg, int default_to_scsi);
 
 DriveInfo *add_init_drive(const char *opts);
 
+void qmp_change_blockdev(const char *device, const char *filename,
+                         bool has_format, const char *format, Error **errp);
 void do_commit(Monitor *mon, const QDict *qdict);
-int do_change_block(Monitor *mon, const char *device,
-                    const char *filename, const char *fmt);
 int do_drive_del(Monitor *mon, const QDict *qdict, QObject **ret_data);
 int do_block_set_io_throttle(Monitor *mon,
                              const QDict *qdict, QObject **ret_data);

hmp-commands.hx

@@ -107,8 +107,7 @@ ETEXI
         .args_type  = "device:B,target:F,arg:s?",
         .params     = "device filename [format]",
         .help       = "change a removable medium, optional format",
-        .user_print = monitor_user_noop,
-        .mhandler.cmd_new = do_change,
+        .mhandler.cmd = hmp_change,
     },
 
 STEXI

hmp.c

@@ -712,3 +712,60 @@ void hmp_eject(Monitor *mon, const QDict *qdict)
     qmp_eject(device, true, force, &err);
     hmp_handle_error(mon, &err);
 }
+
+static void hmp_change_read_arg(Monitor *mon, const char *password,
+                                void *opaque)
+{
+    qmp_change_vnc_password(password, NULL);
+    monitor_read_command(mon, 1);
+}
+
+static void cb_hmp_change_bdrv_pwd(Monitor *mon, const char *password,
+                                   void *opaque)
+{
+    Error *encryption_err = opaque;
+    Error *err = NULL;
+    const char *device;
+
+    device = error_get_field(encryption_err, "device");
+
+    qmp_block_passwd(device, password, &err);
+    hmp_handle_error(mon, &err);
+    error_free(encryption_err);
+
+    monitor_read_command(mon, 1);
+}
+
+void hmp_change(Monitor *mon, const QDict *qdict)
+{
+    const char *device = qdict_get_str(qdict, "device");
+    const char *target = qdict_get_str(qdict, "target");
+    const char *arg = qdict_get_try_str(qdict, "arg");
+    Error *err = NULL;
+
+    if (strcmp(device, "vnc") == 0 &&
+            (strcmp(target, "passwd") == 0 ||
+             strcmp(target, "password") == 0)) {
+        if (!arg) {
+            monitor_read_password(mon, hmp_change_read_arg, NULL);
+            return;
+        }
+    }
+
+    qmp_change(device, target, !!arg, arg, &err);
+    if (error_is_type(err, QERR_DEVICE_ENCRYPTED)) {
+        monitor_printf(mon, "%s (%s) is encrypted.\n",
+                       error_get_field(err, "device"),
+                       error_get_field(err, "filename"));
+        if (!monitor_get_rs(mon)) {
+            monitor_printf(mon,
+                    "terminal does not support password prompting\n");
+            error_free(err);
+            return;
+        }
+        readline_start(monitor_get_rs(mon), "Password: ", 1,
+                       cb_hmp_change_bdrv_pwd, err);
+        return;
+    }
+    hmp_handle_error(mon, &err);
+}

hmp.h

@@ -52,5 +52,6 @@ void hmp_migrate_set_speed(Monitor *mon, const QDict *qdict);
 void hmp_set_password(Monitor *mon, const QDict *qdict);
 void hmp_expire_password(Monitor *mon, const QDict *qdict);
 void hmp_eject(Monitor *mon, const QDict *qdict);
+void hmp_change(Monitor *mon, const QDict *qdict);
 
 #endif

monitor.c

@@ -810,80 +810,6 @@ static void do_trace_print_events(Monitor *mon)
     trace_print_events((FILE *)mon, &monitor_fprintf);
 }
 
-#ifdef CONFIG_VNC
-static int change_vnc_password(const char *password)
-{
-    if (!password || !password[0]) {
-        if (vnc_display_disable_login(NULL)) {
-            qerror_report(QERR_SET_PASSWD_FAILED);
-            return -1;
-        }
-        return 0;
-    }
-
-    if (vnc_display_password(NULL, password) < 0) {
-        qerror_report(QERR_SET_PASSWD_FAILED);
-        return -1;
-    }
-
-    return 0;
-}
-
-static void change_vnc_password_cb(Monitor *mon, const char *password,
-                                   void *opaque)
-{
-    change_vnc_password(password);
-    monitor_read_command(mon, 1);
-}
-
-static int do_change_vnc(Monitor *mon, const char *target, const char *arg)
-{
-    if (strcmp(target, "passwd") == 0 ||
-        strcmp(target, "password") == 0) {
-        if (arg) {
-            char password[9];
-            strncpy(password, arg, sizeof(password));
-            password[sizeof(password) - 1] = '\0';
-            return change_vnc_password(password);
-        } else {
-            return monitor_read_password(mon, change_vnc_password_cb, NULL);
-        }
-    } else {
-        if (vnc_display_open(NULL, target) < 0) {
-            qerror_report(QERR_VNC_SERVER_FAILED, target);
-            return -1;
-        }
-    }
-
-    return 0;
-}
-#else
-static int do_change_vnc(Monitor *mon, const char *target, const char *arg)
-{
-    qerror_report(QERR_FEATURE_DISABLED, "vnc");
-    return -ENODEV;
-}
-#endif
-
-/**
- * do_change(): Change a removable medium, or VNC configuration
- */
-static int do_change(Monitor *mon, const QDict *qdict, QObject **ret_data)
-{
-    const char *device = qdict_get_str(qdict, "device");
-    const char *target = qdict_get_str(qdict, "target");
-    const char *arg = qdict_get_try_str(qdict, "arg");
-    int ret;
-
-    if (strcmp(device, "vnc") == 0) {
-        ret = do_change_vnc(mon, target, arg);
-    } else {
-        ret = do_change_block(mon, device, target, arg);
-    }
-
-    return ret;
-}
-
 static int add_graphics_client(Monitor *mon, const QDict *qdict, QObject **ret_data)
 {
     const char *protocol  = qdict_get_str(qdict, "protocol");

qapi-schema.json

@@ -1366,3 +1366,39 @@
 #         string.  Existing clients are unaffected by executing this command.
 ##
 { 'command': 'change-vnc-password', 'data': {'password': 'str'} }
+
+##
+# @change:
+#
+# This command is multiple commands multiplexed together.
+#
+# @device: This is normally the name of a block device but it may also be 'vnc'.
+#          when it's 'vnc', then sub command depends on @target
+#
+# @target: If @device is a block device, then this is the new filename.
+#          If @device is 'vnc', then if the value 'password' selects the vnc
+#          change password command.   Otherwise, this specifies a new server URI
+#          address to listen to for VNC connections.
+#
+# @arg:    If @device is a block device, then this is an optional format to open
+#          the device with.
+#          If @device is 'vnc' and @target is 'password', this is the new VNC
+#          password to set.  If this argument is an empty string, then no future
+#          logins will be allowed.
+#
+# Returns: Nothing on success.
+#          If @device is not a valid block device, DeviceNotFound
+#          If @format is not a valid block format, InvalidBlockFormat
+#          If the new block device is encrypted, DeviceEncrypted.  Note that
+#          if this error is returned, the device has been opened successfully
+#          and an additional call to @block_passwd is required to set the
+#          device's password.  The behavior of reads and writes to the block
+#          device between when these calls are executed is undefined.
+#
+# Notes:  It is strongly recommended that this interface is not used especially
+#         for changing block devices.
+#
+# Since: 0.14.0
+##
+{ 'command': 'change',
+  'data': {'device': 'str', 'target': 'str', '*arg': 'str'} }

qmp-commands.hx

@@ -110,10 +110,7 @@ EQMP
     {
         .name       = "change",
         .args_type  = "device:B,target:F,arg:s?",
-        .params     = "device filename [format]",
-        .help       = "change a removable medium, optional format",
-        .user_print = monitor_user_noop,
-        .mhandler.cmd_new = do_change,
+        .mhandler.cmd_new = qmp_marshal_input_change,
     },
 
 SQMP

qmp.c

@@ -23,6 +23,7 @@
 #include "hw/qdev.h"
 #include "qapi/qmp-input-visitor.h"
 #include "qapi/qmp-output-visitor.h"
+#include "blockdev.h"
 
 NameInfo *qmp_query_name(Error **errp)
 {
@@ -345,9 +346,52 @@ void qmp_expire_password(const char *protocol, const char *whenstr,
     error_set(errp, QERR_INVALID_PARAMETER, "protocol");
 }
 
+#ifdef CONFIG_VNC
 void qmp_change_vnc_password(const char *password, Error **errp)
 {
     if (vnc_display_password(NULL, password) < 0) {
         error_set(errp, QERR_SET_PASSWD_FAILED);
     }
 }
+
+static void qmp_change_vnc_listen(const char *target, Error **err)
+{
+    if (vnc_display_open(NULL, target) < 0) {
+        error_set(err, QERR_VNC_SERVER_FAILED, target);
+    }
+}
+
+static void qmp_change_vnc(const char *target, bool has_arg, const char *arg,
+                           Error **errp)
+{
+    if (strcmp(target, "passwd") == 0 || strcmp(target, "password") == 0) {
+        if (!has_arg) {
+            error_set(errp, QERR_MISSING_PARAMETER, "password");
+        } else {
+            qmp_change_vnc_password(arg, errp);
+        }
+    } else {
+        qmp_change_vnc_listen(target, errp);
+    }
+}
+#else
+void qmp_change_vnc_password(const char *password, Error **errp)
+{
+    error_set(errp, QERR_FEATURE_DISABLED, "vnc");
+}
+static void qmp_change_vnc(const char *target, bool has_arg, const char *arg,
+                           Error **errp)
+{
+    error_set(errp, QERR_FEATURE_DISABLED, "vnc");
+}
+#endif /* !CONFIG_VNC */
+
+void qmp_change(const char *device, const char *target,
+                bool has_arg, const char *arg, Error **err)
+{
+    if (strcmp(device, "vnc") == 0) {
+        qmp_change_vnc(target, has_arg, arg, err);
+    } else {
+        qmp_change_blockdev(device, target, has_arg, arg, err);
+    }
+}