Adds support for nanosecond resolution file information where available (Fixes: 6283) (#6307)

* Adds support for nanosecond resolution file information where available.

This patch adds support to the runtime to use the nanosecond
information available on Mac and Linux on `struct stat`.
`stat.st_Xtimespec` strucutre on OSX, and `stat.st_Xtime` and
`stat.st_Xtim.tv_nsec` pair on Linux.

Additionally, this adds support in `Mono.Posix` for MacOS nanosecond stat
data, it already had Linux support before.

* Use ULL here to prevent the computation from overflowing

1 files changed, 25 insertions, 12 deletions

diff --git a/support/sys-stat.c b/support/sys-stat.c
index d6abce4a1fa..af2731cccbf 100644
--- a/support/sys-stat.c
+++ b/support/sys-stat.c
@@ -51,16 +51,24 @@ Mono_Posix_FromStat (struct Mono_Posix_Stat *from, void *_to)
 	to->st_atime       = from->st_atime_;
 	to->st_mtime       = from->st_mtime_;
 	to->st_ctime       = from->st_ctime_;
-#ifdef HAVE_STRUCT_STAT_ST_ATIM
+#if HAVE_STRUCT_STAT_ST_ATIMESPEC
+	to->st_atimespec.tv_sec = from->st_atime_;
+	to->st_atimespec.tv_nsec = from->st_atime_nsec;
+	to->st_mtimespec.tv_sec = from->st_mtime_;
+	to->st_mtimespec.tv_nsec = from->st_mtime_nsec;
+	to->st_ctimespec.tv_sec = from->st_ctime_;
+	to->st_ctimespec.tv_nsec = from->st_ctime_nsec;
+#else
+#    ifdef HAVE_STRUCT_STAT_ST_ATIM
 	to->st_atim.tv_nsec = from->st_atime_nsec;
-#endif
-#ifdef HAVE_STRUCT_STAT_ST_MTIM
+#    endif
+#    ifdef HAVE_STRUCT_STAT_ST_MTIM
 	to->st_mtim.tv_nsec = from->st_mtime_nsec;
-#endif
-#ifdef HAVE_STRUCT_STAT_ST_CTIM
+#    endif
+#    ifdef HAVE_STRUCT_STAT_ST_CTIM
 	to->st_ctim.tv_nsec = from->st_ctime_nsec;
+#    endif
 #endif
-
 	return 0;
 }
 
@@ -87,16 +95,21 @@ Mono_Posix_ToStat (void *_from, struct Mono_Posix_Stat *to)
 	to->st_atime_     = from->st_atime;
 	to->st_mtime_     = from->st_mtime;
 	to->st_ctime_     = from->st_ctime;
-#ifdef HAVE_STRUCT_STAT_ST_ATIM
+#if HAVE_STRUCT_STAT_ST_ATIMESPEC
+	to->st_atime_nsec = from->st_atimespec.tv_nsec;
+	to->st_mtime_nsec = from->st_mtimespec.tv_nsec;
+	to->st_ctime_nsec = from->st_ctimespec.tv_nsec;
+#else
+#    ifdef HAVE_STRUCT_STAT_ST_ATIM
 	to->st_atime_nsec = from->st_atim.tv_nsec;
-#endif
-#ifdef HAVE_STRUCT_STAT_ST_MTIM
+#    endif
+#    ifdef HAVE_STRUCT_STAT_ST_MTIM
 	to->st_mtime_nsec = from->st_mtim.tv_nsec;
-#endif
-#ifdef HAVE_STRUCT_STAT_ST_CTIM
+#    endif
+#    ifdef HAVE_STRUCT_STAT_ST_CTIM
 	to->st_ctime_nsec = from->st_ctim.tv_nsec;
+#    endif
 #endif
-
 	return 0;
 }