[PATCH v5 06/16] hw/9pfs: Support getting current directory offset for Windows

[Bin Meng <bin.meng@windriver.com>]

From: Guohuai Shi <guohuai.shi@windriver.com>

On Windows 'struct dirent' does not have current directory offset.
Update qemu_dirent_off() to support Windows.

While we are here, add a build time check to error out if a new
host does not implement this helper.

Signed-off-by: Guohuai Shi <guohuai.shi@windriver.com>
Signed-off-by: Bin Meng <bin.meng@windriver.com>
---

 hw/9pfs/9p-util.h       | 16 +++++++++++++---
 hw/9pfs/9p-util-win32.c |  5 +++++
 hw/9pfs/9p.c            |  4 ++--
 hw/9pfs/codir.c         |  2 +-
 4 files changed, 21 insertions(+), 6 deletions(-)

diff --git a/hw/9pfs/9p-util.h b/hw/9pfs/9p-util.h
index c1c251fbd1..91f70a4c38 100644
--- a/hw/9pfs/9p-util.h
+++ b/hw/9pfs/9p-util.h
@@ -19,6 +19,10 @@
 #define O_PATH_9P_UTIL 0
 #endif
 
+/* forward declaration */
+union V9fsFidOpenState;
+struct V9fsState;
+
 #if !defined(CONFIG_LINUX)
 
 /*
@@ -147,6 +151,7 @@ struct dirent *readdir_win32(DIR *pDir);
 void rewinddir_win32(DIR *pDir);
 void seekdir_win32(DIR *pDir, long pos);
 long telldir_win32(DIR *pDir);
+off_t qemu_dirent_off_win32(struct V9fsState *s, union V9fsFidOpenState *fs);
 #endif
 
 static inline void close_preserve_errno(int fd)
@@ -220,12 +225,17 @@ ssize_t fremovexattrat_nofollow(int dirfd, const char *filename,
  * so ensure it is manually injected earlier and call here when
  * needed.
  */
-static inline off_t qemu_dirent_off(struct dirent *dent)
+static inline off_t qemu_dirent_off(struct dirent *dent, struct V9fsState *s,
+                                    union V9fsFidOpenState *fs)
 {
-#ifdef CONFIG_DARWIN
+#if defined(CONFIG_DARWIN)
     return dent->d_seekoff;
-#else
+#elif defined(CONFIG_LINUX)
     return dent->d_off;
+#elif defined(CONFIG_WIN32)
+    return qemu_dirent_off_win32(s, fs);
+#else
+#error Missing qemu_dirent_off() implementation for this host system
 #endif
 }
 
diff --git a/hw/9pfs/9p-util-win32.c b/hw/9pfs/9p-util-win32.c
index e9408f3c45..37d98a3e63 100644
--- a/hw/9pfs/9p-util-win32.c
+++ b/hw/9pfs/9p-util-win32.c
@@ -1420,3 +1420,8 @@ long telldir_win32(DIR *pDir)
 
     return (long)stream->offset;
 }
+
+off_t qemu_dirent_off_win32(struct V9fsState *s, union V9fsFidOpenState *fs)
+{
+    return s->ops->telldir(&s->ctx, fs);
+}
diff --git a/hw/9pfs/9p.c b/hw/9pfs/9p.c
index 9621ec1341..1b252c6eaf 100644
--- a/hw/9pfs/9p.c
+++ b/hw/9pfs/9p.c
@@ -2334,7 +2334,7 @@ static int coroutine_fn v9fs_do_readdir_with_stat(V9fsPDU *pdu,
         count += len;
         v9fs_stat_free(&v9stat);
         v9fs_path_free(&path);
-        saved_dir_pos = qemu_dirent_off(dent);
+        saved_dir_pos = qemu_dirent_off(dent, pdu->s, &fidp->fs);
     }
 
     v9fs_readdir_unlock(&fidp->fs.dir);
@@ -2535,7 +2535,7 @@ static int coroutine_fn v9fs_do_readdir(V9fsPDU *pdu, V9fsFidState *fidp,
             qid.version = 0;
         }
 
-        off = qemu_dirent_off(dent);
+        off = qemu_dirent_off(dent, pdu->s, &fidp->fs);
         v9fs_string_init(&name);
         v9fs_string_sprintf(&name, "%s", dent->d_name);
 
diff --git a/hw/9pfs/codir.c b/hw/9pfs/codir.c
index 7ba63be489..6d96e2d72b 100644
--- a/hw/9pfs/codir.c
+++ b/hw/9pfs/codir.c
@@ -167,7 +167,7 @@ static int do_readdir_many(V9fsPDU *pdu, V9fsFidState *fidp,
         }
 
         size += len;
-        saved_dir_pos = qemu_dirent_off(dent);
+        saved_dir_pos = qemu_dirent_off(dent, s, &fidp->fs);
     }
 
     /* restore (last) saved position */
-- 
2.25.1