[PATCH v3 07/17] hw/9pfs: Support getting current directory offset for Windows

[Bin Meng]

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>
---

(no changes since v1)

 hw/9pfs/9p-util.h       | 11 ++++++++---
 hw/9pfs/9p-util-win32.c |  7 +++++++
 hw/9pfs/9p.c            |  4 ++--
 hw/9pfs/codir.c         |  2 +-
 4 files changed, 18 insertions(+), 6 deletions(-)

diff --git a/hw/9pfs/9p-util.h b/hw/9pfs/9p-util.h
index 90420a7578..e395936b30 100644
--- a/hw/9pfs/9p-util.h
+++ b/hw/9pfs/9p-util.h
@@ -127,6 +127,7 @@ int unlinkat_win32(int dirfd, const char *pathname, int 
flags);
 int statfs_win32(const char *root_path, struct statfs *stbuf);
 int openat_dir(int dirfd, const char *name);
 int openat_file(int dirfd, const char *name, int flags, mode_t mode);
+off_t qemu_dirent_off_win32(void *s, void *fs);
 #endif
 
 static inline void close_preserve_errno(int fd)
@@ -200,12 +201,16 @@ 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, void *s, void *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 7a270a7bd5..3592e057ce 100644
--- a/hw/9pfs/9p-util-win32.c
+++ b/hw/9pfs/9p-util-win32.c
@@ -929,3 +929,10 @@ int qemu_mknodat(int dirfd, const char *filename, mode_t 
mode, dev_t dev)
     errno = ENOTSUP;
     return -1;
 }
+
+off_t qemu_dirent_off_win32(void *s, void *fs)
+{
+    V9fsState *v9fs = s;
+
+    return v9fs->ops->telldir(&v9fs->ctx, (V9fsFidOpenState *)fs);
+}
diff --git a/hw/9pfs/9p.c b/hw/9pfs/9p.c
index 072cf67956..be247eeb30 100644
--- a/hw/9pfs/9p.c
+++ b/hw/9pfs/9p.c
@@ -2336,7 +2336,7 @@ 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);
@@ -2537,7 +2537,7 @@ 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 93ba44fb75..d40515a607 100644
--- a/hw/9pfs/codir.c
+++ b/hw/9pfs/codir.c
@@ -168,7 +168,7 @@ 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