9p: darwin: Handle struct dirent differences

On darwin d_seekoff exists, but is optional and does not seem to
be commonly used by file systems. Use `telldir` instead to obtain
the seek offset and inject it into d_seekoff, and create a
qemu_dirent_off helper to call it appropriately when appropriate.

Signed-off-by: Keno Fischer <keno@juliacomputing.com>
[Michael Roitzsch: - Rebase for NixOS]
Signed-off-by: Michael Roitzsch <reactorcontrol@icloud.com>
[Will Cohen: - Adjust to pass testing
             - Ensure that d_seekoff is filled using telldir
               on darwin, and create qemu_dirent_off helper
               to decide which to access]
[Fabian Franz: - Add telldir error handling for darwin]
Signed-off-by: Fabian Franz <fabianfranz.oss@gmail.com>
[Will Cohen: - Ensure that telldir error handling uses
               signed int
             - Cleanup of telldir error handling
             - Remove superfluous error handling for
               qemu_dirent_off
             - Adjust formatting
             - Use qemu_dirent_off in codir.c
             - Declare qemu_dirent_off as static to prevent
               linker error
             - Move qemu_dirent_off above the end-of-file
               endif to fix compilation]
Signed-off-by: Will Cohen <wwcohen@gmail.com>
Message-Id: <20220227223522.91937-5-wwcohen@gmail.com>
Signed-off-by: Christian Schoenebeck <qemu_oss@crudebyte.com>
Reviewed-by: Christian Schoenebeck <qemu_oss@crudebyte.com>

1 files changed, 3 insertions, 1 deletions

diff --git a/hw/9pfs/codir.c b/hw/9pfs/codir.c
index c0873bde16..f96d8ac4e6 100644
--- a/hw/9pfs/codir.c
+++ b/hw/9pfs/codir.c
@@ -22,6 +22,8 @@
 #include "qemu/coroutine.h"
 #include "qemu/main-loop.h"
 #include "coth.h"
+#include "9p-xattr.h"
+#include "9p-util.h"
 
 /*
  * Intended to be called from bottom-half (e.g. background I/O thread)
@@ -166,7 +168,7 @@ static int do_readdir_many(V9fsPDU *pdu, V9fsFidState *fidp,
         }
 
         size += len;
-        saved_dir_pos = dent->d_off;
+        saved_dir_pos = qemu_dirent_off(dent);
     }
 
     /* restore (last) saved position */