block/ssh: Implement .bdrv_dirname()

ssh_bdrv_dirname() is basically the generic bdrv_dirname(), except it
takes care not to silently chop off any query string (i.e.,
host_key_check).

Signed-off-by: Max Reitz <mreitz@redhat.com>
Tested-by: Richard W.M. Jones <rjones@redhat.com>
Message-id: 20190225190828.17726-3-mreitz@redhat.com
Signed-off-by: Max Reitz <mreitz@redhat.com>

1 files changed, 21 insertions, 0 deletions

diff --git a/block/ssh.c b/block/ssh.c
index 2eaeab8..12fd4f3 100644
--- a/block/ssh.c
+++ b/block/ssh.c
@@ -1283,6 +1283,26 @@ static void ssh_refresh_filename(BlockDriverState *bs)
     }
 }
 
+static char *ssh_bdrv_dirname(BlockDriverState *bs, Error **errp)
+{
+    if (qdict_haskey(bs->full_open_options, "host_key_check")) {
+        /*
+         * We cannot generate a simple prefix if we would have to
+         * append a query string.
+         */
+        error_setg(errp,
+                   "Cannot generate a base directory with host_key_check set");
+        return NULL;
+    }
+
+    if (bs->exact_filename[0] == '\0') {
+        error_setg(errp, "Cannot generate a base directory for this ssh node");
+        return NULL;
+    }
+
+    return path_combine(bs->exact_filename, "");
+}
+
 static const char *const ssh_strong_runtime_opts[] = {
     "host",
     "port",
@@ -1310,6 +1330,7 @@ static BlockDriver bdrv_ssh = {
     .bdrv_co_truncate             = ssh_co_truncate,
     .bdrv_co_flush_to_disk        = ssh_co_flush,
     .bdrv_refresh_filename        = ssh_refresh_filename,
+    .bdrv_dirname                 = ssh_bdrv_dirname,
     .create_opts                  = &ssh_create_opts,
     .strong_runtime_opts          = ssh_strong_runtime_opts,
 };