[Qemu-devel] [PATCH v2 09/20] 9p: Properly check/translate flags in unlinkat

[Keno Fischer]

This code previously relied on P9_DOTL_AT_REMOVEDIR and AT_REMOVEDIR
having the same numerical value and deferred any errorchecking to the
syscall itself. However, while the former assumption is true on Linux,
it is not true in general. Thus, add appropriate error checking and
translation to the 9p unlinkat server code.

Signed-off-by: Keno Fischer <address@hidden>
---

Changes since v1:
 * Code was moved from 9p-local.c to server entry point in 9p.c

 hw/9pfs/9p.c | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/hw/9pfs/9p.c b/hw/9pfs/9p.c
index b80db65..a757374 100644
--- a/hw/9pfs/9p.c
+++ b/hw/9pfs/9p.c
@@ -2522,7 +2522,7 @@ static void coroutine_fn v9fs_unlinkat(void *opaque)
 {
     int err = 0;
     V9fsString name;
-    int32_t dfid, flags;
+    int32_t dfid, flags, rflags = 0;
     size_t offset = 7;
     V9fsPath path;
     V9fsFidState *dfidp;
@@ -2549,6 +2549,15 @@ static void coroutine_fn v9fs_unlinkat(void *opaque)
         goto out_nofid;
     }
 
+    if (flags & ~P9_DOTL_AT_REMOVEDIR) {
+        err = -EINVAL;
+        goto out_nofid;
+    }
+
+    if (flags & P9_DOTL_AT_REMOVEDIR) {
+        rflags |= AT_REMOVEDIR;
+    }
+
     dfidp = get_fid(pdu, dfid);
     if (dfidp == NULL) {
         err = -EINVAL;
@@ -2567,7 +2576,7 @@ static void coroutine_fn v9fs_unlinkat(void *opaque)
     if (err < 0) {
         goto out_err;
     }
-    err = v9fs_co_unlinkat(pdu, &dfidp->path, &name, flags);
+    err = v9fs_co_unlinkat(pdu, &dfidp->path, &name, rflags);
     if (!err) {
         err = offset;
     }
-- 
2.8.1