Add fsetxattr(), fremovexattr(), open_by_handle_at(), and "virtiofsd demo"

Mostly assorted fixes, a new FDGET operation (get a copy of the
target file descriptor via pidfd_getfd()) and a new "FD" flag that
means we have to do that on direct tag reference.

Signed-off-by: Stefano Brivio <sbrivio@redhat.com>

1 files changed, 93 insertions, 0 deletions

diff --git a/demo/virtiofsd.hjson b/demo/virtiofsd.hjson
new file mode 100644
index 0000000..8dfde03
--- /dev/null
+++ b/demo/virtiofsd.hjson
@@ -0,0 +1,93 @@
+[
+  {
+    "match": [
+      {
+        "fsetxattr": {
+          "fd": { "set": "fd" },
+          "name": "security.overrated",
+          "value": { "set": "label" },
+          "size": { "set": "size" },
+          "flags": { "set": "flags" }
+        }
+      }
+    ],
+
+    "call": [
+      {
+        "fsetxattr": {
+            "fd": { "get": "fd" },
+            "name": "security.overrated",
+            "value": { "get": "label" },
+            "size": { "get": "size" },
+            "flags": { "get": "flags" }
+        },
+        "ret": "rc"
+      }
+    ],
+
+    "return": { "value": "rc", "error": "rc" }
+  },
+
+  {
+    "match": [
+      {
+        "fremovexattr": {
+          "fd": { "set": "fd" },
+          "name": "security.overrated"
+        }
+      }
+    ],
+
+    "call": [
+      {
+        "fremovexattr": {
+          "fd": { "get": "fd" },
+          "name": "security.overrated"
+        },
+        "ret": "rc"
+      }
+    ],
+
+    "return": { "value": "rc", "error": "rc" }
+  },
+
+  {
+    "match": [
+      {
+        "open_by_handle_at": {
+          "mount": "/",
+          "handle": {
+              "handle_bytes": { "set": "len" },
+              "f_handle": { "set": "handle" }
+          },
+          "flags": { "set": "flags" }
+        }
+      }
+    ],
+
+    "call": [
+      {
+        "open": {
+            "path": "/",
+            "flags": "rdonly",
+            "mode": "S_IRUSR"
+        },
+        "ret": "fdmount"
+      },
+      {
+        "open_by_handle_at": {
+          "mount": { "get": "fdmount" },
+          "handle": {
+              "handle_type": "ino32_gen",
+              "handle_bytes": { "get": "len" },
+              "f_handle": { "get": "handle" }
+          },
+          "flags": { "get": "flags" }
+        },
+        "ret": "new_fd"
+      }
+    ],
+
+    "fd": { "src": { "get": "new_fd" }, "close_on_exec": false, "return": true }
+  }
+]