[PULL,6/7] tests/9pfs: guard recent 'Twalk' behaviour fix

Commit Message

Christian Schoenebeck June 16, 2022, 11 a.m. UTC

Previous 9p patch fixed 'Twalk' request handling, which was previously not
behaving as specified by the 9p2000 protocol spec. This patch adds a new test
case which guards the new 'Twalk' behaviour in question.

More specifically: it sends a 'Twalk' request where the 1st path component
is valid, whereas the 2nd path component transmitted to server does not
exist. The expected behaviour is that 9p server would respond by sending
a 'Rwalk' response with exactly 1 QID (instead of 'Rlerror' response).

Signed-off-by: Christian Schoenebeck <[e-mail]>
Reviewed-by: Greg Kurz <[e-mail]>
Message-Id: <[e-mail]>
---
 tests/qtest/virtio-9p-test.c | 42 +++++++++++++++++++++++++++++++++---
 1 file changed, 39 insertions(+), 3 deletions(-)

Patch

diff --git a/tests/qtest/virtio-9p-test.c b/tests/qtest/virtio-9p-test.c
index 3c0f094929..c787ded4d2 100644
--- a/tests/qtest/virtio-9p-test.c
+++ b/tests/qtest/virtio-9p-test.c
@@ -669,8 +669,12 @@  static void do_version(QVirtio9P *v9p)
     g_assert_cmpmem(server_version, server_len, version, strlen(version));
 }
 
-/* utility function: walk to requested dir and return fid for that dir */
-static uint32_t do_walk(QVirtio9P *v9p, const char *path)
+/*
+ * utility function: walk to requested dir and return fid for that dir and
+ * the QIDs of server response
+ */
+static uint32_t do_walk_rqids(QVirtio9P *v9p, const char *path, uint16_t *nwqid,
+                              v9fs_qid **wqid)
 {
     char **wnames;
     P9Req *req;
@@ -680,12 +684,18 @@  static uint32_t do_walk(QVirtio9P *v9p, const char *path)
 
     req = v9fs_twalk(v9p, 0, fid, nwnames, wnames, 0);
     v9fs_req_wait_for_reply(req, NULL);
-    v9fs_rwalk(req, NULL, NULL);
+    v9fs_rwalk(req, nwqid, wqid);
 
     split_free(&wnames);
     return fid;
 }
 
+/* utility function: walk to requested dir and return fid for that dir */
+static uint32_t do_walk(QVirtio9P *v9p, const char *path)
+{
+    return do_walk_rqids(v9p, path, NULL, NULL);
+}
+
 /* utility function: walk to requested dir and expect passed error response */
 static void do_walk_expect_error(QVirtio9P *v9p, const char *path, uint32_t err)
 {
@@ -1079,9 +1089,33 @@  static void fs_walk_nonexistent(void *obj, void *data, QGuestAllocator *t_alloc)
     alloc = t_alloc;
 
     do_attach(v9p);
+    /*
+     * The 9p2000 protocol spec says: "If the first element cannot be walked
+     * for any reason, Rerror is returned."
+     */
     do_walk_expect_error(v9p, "non-existent", ENOENT);
 }
 
+static void fs_walk_2nd_nonexistent(void *obj, void *data,
+                                    QGuestAllocator *t_alloc)
+{
+    QVirtio9P *v9p = obj;
+    alloc = t_alloc;
+    uint16_t nwqid;
+    g_autofree v9fs_qid *wqid = NULL;
+    g_autofree char *path = g_strdup_printf(
+        QTEST_V9FS_SYNTH_WALK_FILE "/non-existent", 0
+    );
+
+    do_attach(v9p);
+    do_walk_rqids(v9p, path, &nwqid, &wqid);
+    /*
+     * The 9p2000 protocol spec says: "nwqid is therefore either nwname or the
+     * index of the first elementwise walk that failed."
+     */
+    assert(nwqid == 1);
+}
+
 static void fs_walk_none(void *obj, void *data, QGuestAllocator *t_alloc)
 {
     QVirtio9P *v9p = obj;
@@ -1548,6 +1582,8 @@  static void register_virtio_9p_test(void)
                  fs_walk_dotdot,  &opts);
     qos_add_test("synth/walk/non_existent", "virtio-9p", fs_walk_nonexistent,
                   &opts);
+    qos_add_test("synth/walk/2nd_non_existent", "virtio-9p",
+                 fs_walk_2nd_nonexistent, &opts);
     qos_add_test("synth/lopen/basic", "virtio-9p", fs_lopen,  &opts);
     qos_add_test("synth/write/basic", "virtio-9p", fs_write,  &opts);
     qos_add_test("synth/flush/success", "virtio-9p", fs_flush_success,