9p: linux: Fix a couple Linux assumptions

 - Guard Linux only headers.
 - Add qemu/statfs.h header to abstract over the which
   headers are needed for struct statfs
 - Define `ENOATTR` only if not only defined
   (it's defined in system headers on Darwin).

Signed-off-by: Keno Fischer <keno@juliacomputing.com>
[Michael Roitzsch: - Rebase for NixOS]
Signed-off-by: Michael Roitzsch <reactorcontrol@icloud.com>

While it might at first appear that fsdev/virtfs-proxy-header.c would
need similar adjustment for darwin as file-op-9p here, a later patch in
this series disables virtfs-proxy-helper for non-Linux. Allowing
virtfs-proxy-helper on darwin could potentially be an additional
optimization later.

[Will Cohen: - Fix headers for Alpine
             - Integrate statfs.h back into file-op-9p.h
             - Remove superfluous header guards from file-opt-9p
             - Add note about virtfs-proxy-helper being disabled
               on non-Linux for this patch series]
Signed-off-by: Will Cohen <wwcohen@gmail.com>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Greg Kurz <groug@kaod.org>
Message-Id: <20220227223522.91937-2-wwcohen@gmail.com>
Signed-off-by: Christian Schoenebeck <qemu_oss@crudebyte.com>

1 files changed, 4 insertions, 0 deletions

diff --git a/hw/9pfs/9p.c b/hw/9pfs/9p.c
index 15b3f4d..9c63e14 100644
--- a/hw/9pfs/9p.c
+++ b/hw/9pfs/9p.c
@@ -32,7 +32,11 @@
 #include "migration/blocker.h"
 #include "qemu/xxhash.h"
 #include <math.h>
+#ifdef CONFIG_LINUX
 #include <linux/limits.h>
+#else
+#include <limits.h>
+#endif
 
 int open_fd_hw;
 int total_open_fd;