[PATCH] Cygwin: fsync: Fix EINVAL for block device.

[Takashi Yano]

The commit af8a7c13b516 has a problem that fsync returns EINVAL for
block device. This patch treats block devices as a special case.
https://cygwin.com/pipermail/cygwin/2023-January/252916.html

Fixes: af8a7c13b516 ("Cygwin: fsync: Return EINVAL for special files.")
Signed-off-by: Takashi Yano <takashi.y...@nifty.ne.jp>
---
 winsup/cygwin/fhandler/base.cc | 23 ++++++++++++++++++++++-
 1 file changed, 22 insertions(+), 1 deletion(-)

diff --git a/winsup/cygwin/fhandler/base.cc b/winsup/cygwin/fhandler/base.cc
index b2738cf20..fc0410522 100644
--- a/winsup/cygwin/fhandler/base.cc
+++ b/winsup/cygwin/fhandler/base.cc
@@ -1725,10 +1725,31 @@ fhandler_base::utimens (const struct timespec *tvp)
   return -1;
 }
 
+static bool
+is_block_device (_major_t major)
+{
+  switch (major)
+    {
+    case DEV_FLOPPY_MAJOR:
+    case DEV_SD_MAJOR:
+    case DEV_CDROM_MAJOR:
+    case DEV_SD1_MAJOR:
+    case DEV_SD2_MAJOR:
+    case DEV_SD3_MAJOR:
+    case DEV_SD4_MAJOR:
+    case DEV_SD5_MAJOR:
+    case DEV_SD6_MAJOR:
+    case DEV_SD7_MAJOR:
+      return true;
+    }
+  return false;
+}
+
 int
 fhandler_base::fsync ()
 {
-  if (!get_handle () || nohandle () || pc.isspecial ())
+  if (!get_handle () || nohandle ()
+      || (pc.isspecial () && !is_block_device (get_major ())))
     {
       set_errno (EINVAL);
       return -1;
-- 
2.39.0