[Qemu-devel] [PATCH 12/13] 9p: darwin: Provide a fallback implementation for utimensat

[keno]

From: Keno Fischer <address@hidden>

This function is new in Mac OS 10.13. Provide a fallback implementation
when building against older SDKs.

Signed-off-by: Keno Fischer <address@hidden>
---
 hw/9pfs/9p-local.c |  2 +-
 hw/9pfs/9p-util.c  | 38 ++++++++++++++++++++++++++++++++++++++
 hw/9pfs/9p-util.h  |  7 +++++++
 hw/9pfs/9p.c       |  1 +
 4 files changed, 47 insertions(+), 1 deletion(-)

diff --git a/hw/9pfs/9p-local.c b/hw/9pfs/9p-local.c
index 3e358b7..70ab541 100644
--- a/hw/9pfs/9p-local.c
+++ b/hw/9pfs/9p-local.c
@@ -1082,7 +1082,7 @@ static int local_utimensat(FsContext *s, V9fsPath 
*fs_path,
         goto out;
     }
 
-    ret = utimensat(dirfd, name, buf, AT_SYMLINK_NOFOLLOW);
+    ret = utimensat_nofollow(dirfd, name, buf);
     close_preserve_errno(dirfd);
 out:
     g_free(dirpath);
diff --git a/hw/9pfs/9p-util.c b/hw/9pfs/9p-util.c
index 98004ac..8403f5f 100644
--- a/hw/9pfs/9p-util.c
+++ b/hw/9pfs/9p-util.c
@@ -104,3 +104,41 @@ int fsetxattrat_nofollow(int dirfd, const char *filename, 
const char *name,
 #endif
     return ret;
 }
+
+#ifndef __has_builtin
+#define __has_builtin(x) 0
+#endif
+
+int utimensat_nofollow(int dirfd, const char *filename, const struct timespec 
times[2])
+{
+#ifdef CONFIG_DARWIN
+#if defined(__MAC_10_13) /* Check whether we have an SDK version that defines 
utimensat */
+#if __MAC_OS_X_VERSION_MIN_REQUIRED >= __MAC_10_13
+#define UTIMENSAT_AVAILABLE 1
+#elif __has_builtin(__builtin_available)
+#define UTIMENSAT_AVAILABLE __builtin_available(macos 10.13, *)
+#else
+#define UTIMENSAT_AVAILABLE 0
+#endif
+    if (UTIMENSAT_AVAILABLE)
+    {
+        return utimensat(dirfd, filename, times, AT_SYMLINK_NOFOLLOW);
+    }
+#endif
+    // utimensat not available. Use futimes.
+    int fd = openat_file(dirfd, filename, O_PATH_9P_UTIL | O_NOFOLLOW, 0);
+    if (fd == -1)
+        return -1;
+
+    struct timeval futimes_buf[2];
+    futimes_buf[0].tv_sec = times[0].tv_sec;
+    futimes_buf[0].tv_usec = times[0].tv_nsec * 1000;
+    futimes_buf[1].tv_sec = times[1].tv_sec;
+    futimes_buf[1].tv_usec = times[1].tv_nsec * 1000;
+    int ret = futimes(fd, futimes_buf);
+    close_preserve_errno(fd);
+    return ret;
+#else
+    return utimensat(dirfd, filename, times, AT_SYMLINK_NOFOLLOW);
+#endif
+}
diff --git a/hw/9pfs/9p-util.h b/hw/9pfs/9p-util.h
index cb26343..2329c82 100644
--- a/hw/9pfs/9p-util.h
+++ b/hw/9pfs/9p-util.h
@@ -19,6 +19,12 @@
 #define O_PATH_9P_UTIL 0
 #endif
 
+/* Compatibility with OLD SDK Versions for Darwin */
+#if defined(CONFIG_DARWIN) && !defined(UTIME_NOW)
+#define UTIME_NOW -1
+#define UTIME_OMIT -2
+#endif
+
 static inline void close_preserve_errno(int fd)
 {
     int serrno = errno;
@@ -66,5 +72,6 @@ ssize_t flistxattrat_nofollow(int dirfd, const char *filename,
                               char *list, size_t size);
 ssize_t fremovexattrat_nofollow(int dirfd, const char *filename,
                                 const char *name);
+int utimensat_nofollow(int dirfd, const char *filename, const struct timespec 
times[2]);
 
 #endif
diff --git a/hw/9pfs/9p.c b/hw/9pfs/9p.c
index 4ae4da6..8e0594a 100644
--- a/hw/9pfs/9p.c
+++ b/hw/9pfs/9p.c
@@ -21,6 +21,7 @@
 #include "virtio-9p.h"
 #include "fsdev/qemu-fsdev.h"
 #include "9p-xattr.h"
+#include "9p-util.h"
 #include "coth.h"
 #include "trace.h"
 #include "migration/blocker.h"
-- 
2.8.1