block: Don't silently truncate node names

If the user passes a too long node name string, we silently truncate it
to fit into BlockDriverState.node_name, i.e. to 31 characters. Apart
from surprising the user when the node has a different name than
requested, this also bypasses the check for duplicate names, so that the
same name can be assigned to multiple nodes.

Fix this by just making too long node names an error.
Reported-by: NPeter Krempa <pkrempa@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

block.c

@@ -1156,6 +1156,12 @@ static void bdrv_assign_node_name(BlockDriverState *bs,
         goto out;
     }
 
+    /* Make sure that the node name isn't truncated */
+    if (strlen(node_name) >= sizeof(bs->node_name)) {
+        error_setg(errp, "Node name too long");
+        goto out;
+    }
+
     /* copy node name into the bs and insert it into the graph list */
     pstrcpy(bs->node_name, sizeof(bs->node_name), node_name);
     QTAILQ_INSERT_TAIL(&graph_bdrv_states, bs, node_list);

tests/qemu-iotests/051

@@ -99,6 +99,21 @@ run_qemu -drive file="$TEST_IMG",driver=foo
 run_qemu -drive file="$TEST_IMG",driver=raw,format=qcow2
 run_qemu -drive file="$TEST_IMG",driver=qcow2,format=qcow2
 
+echo
+echo === Node names ===
+echo
+
+# Maximum length: 31 characters
+run_qemu -drive file="$TEST_IMG",node-name=x123456789012345678901234567890
+run_qemu -drive file="$TEST_IMG",node-name=x1234567890123456789012345678901
+
+# First character must be alphabetic
+# Following characters alphanumeric or -._
+run_qemu -drive file="$TEST_IMG",node-name=All-Types.of_all0wed_chars
+run_qemu -drive file="$TEST_IMG",node-name=123foo
+run_qemu -drive file="$TEST_IMG",node-name=_foo
+run_qemu -drive file="$TEST_IMG",node-name=foo#12
+
 echo
 echo === Device without drive ===
 echo

tests/qemu-iotests/051.out

@@ -47,6 +47,29 @@ Testing: -drive file=TEST_DIR/t.qcow2,driver=qcow2,format=qcow2
 QEMU_PROG: -drive file=TEST_DIR/t.qcow2,driver=qcow2,format=qcow2: Cannot specify both 'driver' and 'format'
 
 
+=== Node names ===
+
+Testing: -drive file=TEST_DIR/t.qcow2,node-name=x123456789012345678901234567890
+QEMU X.Y.Z monitor - type 'help' for more information
+(qemu) quit
+
+Testing: -drive file=TEST_DIR/t.qcow2,node-name=x1234567890123456789012345678901
+QEMU_PROG: -drive file=TEST_DIR/t.qcow2,node-name=x1234567890123456789012345678901: Node name too long
+
+Testing: -drive file=TEST_DIR/t.qcow2,node-name=All-Types.of_all0wed_chars
+QEMU X.Y.Z monitor - type 'help' for more information
+(qemu) quit
+
+Testing: -drive file=TEST_DIR/t.qcow2,node-name=123foo
+QEMU_PROG: -drive file=TEST_DIR/t.qcow2,node-name=123foo: Invalid node name
+
+Testing: -drive file=TEST_DIR/t.qcow2,node-name=_foo
+QEMU_PROG: -drive file=TEST_DIR/t.qcow2,node-name=_foo: Invalid node name
+
+Testing: -drive file=TEST_DIR/t.qcow2,node-name=foo#12
+QEMU_PROG: -drive file=TEST_DIR/t.qcow2,node-name=foo#12: Invalid node name
+
+
 === Device without drive ===
 
 Testing: -device VIRTIO_SCSI -device scsi-hd

tests/qemu-iotests/051.pc.out

@@ -47,6 +47,29 @@ Testing: -drive file=TEST_DIR/t.qcow2,driver=qcow2,format=qcow2
 QEMU_PROG: -drive file=TEST_DIR/t.qcow2,driver=qcow2,format=qcow2: Cannot specify both 'driver' and 'format'
 
 
+=== Node names ===
+
+Testing: -drive file=TEST_DIR/t.qcow2,node-name=x123456789012345678901234567890
+QEMU X.Y.Z monitor - type 'help' for more information
+(qemu) quit
+
+Testing: -drive file=TEST_DIR/t.qcow2,node-name=x1234567890123456789012345678901
+QEMU_PROG: -drive file=TEST_DIR/t.qcow2,node-name=x1234567890123456789012345678901: Node name too long
+
+Testing: -drive file=TEST_DIR/t.qcow2,node-name=All-Types.of_all0wed_chars
+QEMU X.Y.Z monitor - type 'help' for more information
+(qemu) quit
+
+Testing: -drive file=TEST_DIR/t.qcow2,node-name=123foo
+QEMU_PROG: -drive file=TEST_DIR/t.qcow2,node-name=123foo: Invalid node name
+
+Testing: -drive file=TEST_DIR/t.qcow2,node-name=_foo
+QEMU_PROG: -drive file=TEST_DIR/t.qcow2,node-name=_foo: Invalid node name
+
+Testing: -drive file=TEST_DIR/t.qcow2,node-name=foo#12
+QEMU_PROG: -drive file=TEST_DIR/t.qcow2,node-name=foo#12: Invalid node name
+
+
 === Device without drive ===
 
 Testing: -device VIRTIO_SCSI -device scsi-hd