From 658d873efb95e78dfcbc216e531261e84225d89f Mon Sep 17 00:00:00 2001
From: Bill Zissimopoulos <billziss@navimatics.com>
Date: Tue, 14 Nov 2017 21:37:50 -0800
Subject: [PATCH] dll: fuse: streamline time calculations

---
 inc/winfsp/winfsp.h      | 15 ++++++++++++++
 src/dll/fuse/fuse.c      | 10 ++++-----
 src/dll/fuse/fuse_intf.c | 44 ++++++++--------------------------------
 3 files changed, 27 insertions(+), 42 deletions(-)

diff --git a/inc/winfsp/winfsp.h b/inc/winfsp/winfsp.h
index 7c0951be..9fd5b97f 100644
--- a/inc/winfsp/winfsp.h
+++ b/inc/winfsp/winfsp.h
@@ -1472,6 +1472,21 @@ NTSTATUS FspPosixMapPosixToWindowsPath(const char *PosixPath, PWSTR *PWindowsPat
 FSP_API VOID FspPosixDeletePath(void *Path);
 FSP_API VOID FspPosixEncodeWindowsPath(PWSTR WindowsPath, ULONG Size);
 FSP_API VOID FspPosixDecodeWindowsPath(PWSTR WindowsPath, ULONG Size);
+static inline
+VOID FspPosixFileTimeToUnixTime(UINT64 FileTime0, __int3264 UnixTime[2])
+{
+    INT64 FileTime = (INT64)FileTime0 - 116444736000000000LL;
+    UnixTime[0] = (__int3264)(FileTime / 10000000);
+    UnixTime[1] = (__int3264)(FileTime % 10000000 * 100);
+        /* may produce negative nsec for times before UNIX epoch; strictly speaking this is incorrect */
+}
+static inline
+VOID FspPosixUnixTimeToFileTime(const __int3264 UnixTime[2], PUINT64 PFileTime)
+{
+    INT64 FileTime = (INT64)UnixTime[0] * 10000000 + (INT64)UnixTime[1] / 100 +
+        116444736000000000LL;
+    *PFileTime = FileTime;
+}
 
 /*
  * Path Handling
diff --git a/src/dll/fuse/fuse.c b/src/dll/fuse/fuse.c
index 1f634111..b2ba30bd 100644
--- a/src/dll/fuse/fuse.c
+++ b/src/dll/fuse/fuse.c
@@ -355,14 +355,12 @@ static NTSTATUS fsp_fuse_svcstart(FSP_SERVICE *Service, ULONG argc, PWSTR *argv)
         if (0 == f->VolumeParams.VolumeCreationTime)
         {
             if (0 != stbuf.st_birthtim.tv_sec)
-                f->VolumeParams.VolumeCreationTime =
-                    Int32x32To64(stbuf.st_birthtim.tv_sec, 10000000) + 116444736000000000 +
-                    stbuf.st_birthtim.tv_nsec / 100;
+                FspPosixUnixTimeToFileTime((void *)&stbuf.st_birthtim,
+                    &f->VolumeParams.VolumeCreationTime);
             else
             if (0 != stbuf.st_ctim.tv_sec)
-                f->VolumeParams.VolumeCreationTime =
-                    Int32x32To64(stbuf.st_ctim.tv_sec, 10000000) + 116444736000000000 +
-                    stbuf.st_ctim.tv_nsec / 100;
+                FspPosixUnixTimeToFileTime((void *)&stbuf.st_ctim,
+                    &f->VolumeParams.VolumeCreationTime);
         }
     }
 
diff --git a/src/dll/fuse/fuse_intf.c b/src/dll/fuse/fuse_intf.c
index ae9fe434..7e221d9e 100644
--- a/src/dll/fuse/fuse_intf.c
+++ b/src/dll/fuse/fuse_intf.c
@@ -428,18 +428,10 @@ static NTSTATUS fsp_fuse_intf_GetFileInfoFunnel(FSP_FILE_SYSTEM *FileSystem,
     FileInfo->FileSize = stbuf.st_size;
     FileInfo->AllocationSize =
         (FileInfo->FileSize + AllocationUnit - 1) / AllocationUnit * AllocationUnit;
-    FileInfo->CreationTime =
-        Int32x32To64(stbuf.st_birthtim.tv_sec, 10000000) + 116444736000000000 +
-        stbuf.st_birthtim.tv_nsec / 100;
-    FileInfo->LastAccessTime =
-        Int32x32To64(stbuf.st_atim.tv_sec, 10000000) + 116444736000000000 +
-        stbuf.st_atim.tv_nsec / 100;
-    FileInfo->LastWriteTime =
-        Int32x32To64(stbuf.st_mtim.tv_sec, 10000000) + 116444736000000000 +
-        stbuf.st_mtim.tv_nsec / 100;
-    FileInfo->ChangeTime =
-        Int32x32To64(stbuf.st_ctim.tv_sec, 10000000) + 116444736000000000 +
-        stbuf.st_ctim.tv_nsec / 100;
+    FspPosixUnixTimeToFileTime((void *)&stbuf.st_birthtim, &FileInfo->CreationTime);
+    FspPosixUnixTimeToFileTime((void *)&stbuf.st_atim, &FileInfo->LastAccessTime);
+    FspPosixUnixTimeToFileTime((void *)&stbuf.st_mtim, &FileInfo->LastWriteTime);
+    FspPosixUnixTimeToFileTime((void *)&stbuf.st_ctim, &FileInfo->ChangeTime);
     FileInfo->IndexNumber = stbuf.st_ino;
 
     return STATUS_SUCCESS;
@@ -1306,37 +1298,17 @@ static NTSTATUS fsp_fuse_intf_SetBasicInfo(FSP_FILE_SYSTEM *FileSystem,
                 LastWriteTime = FileInfoBuf.LastWriteTime;
         }
 
-        /* UNIX epoch in 100-ns intervals */
-        LastAccessTime -= 116444736000000000;
-        LastWriteTime -= 116444736000000000;
-
+        FspPosixFileTimeToUnixTime(LastAccessTime, (void *)&tv[0]);
+        FspPosixFileTimeToUnixTime(LastWriteTime, (void *)&tv[1]);
         if (0 != f->ops.utimens)
         {
-#if defined(_WIN64)
-            tv[0].tv_sec = (int64_t)(LastAccessTime / 10000000);
-            tv[0].tv_nsec = (int64_t)(LastAccessTime % 10000000) * 100;
-            tv[1].tv_sec = (int64_t)(LastWriteTime / 10000000);
-            tv[1].tv_nsec = (int64_t)(LastWriteTime % 10000000) * 100;
-#else
-            tv[0].tv_sec = (int32_t)(LastAccessTime / 10000000);
-            tv[0].tv_nsec = (int32_t)(LastAccessTime % 10000000) * 100;
-            tv[1].tv_sec = (int32_t)(LastWriteTime / 10000000);
-            tv[1].tv_nsec = (int32_t)(LastWriteTime % 10000000) * 100;
-#endif
-
             err = f->ops.utimens(filedesc->PosixPath, tv);
             Result = fsp_fuse_ntstatus_from_errno(f->env, err);
         }
         else
         {
-#if defined(_WIN64)
-            timbuf.actime = (int64_t)(LastAccessTime / 10000000);
-            timbuf.modtime = (int64_t)(LastWriteTime / 10000000);
-#else
-            timbuf.actime = (int32_t)(LastAccessTime / 10000000);
-            timbuf.modtime = (int32_t)(LastWriteTime / 10000000);
-#endif
-
+            timbuf.actime = tv[0].tv_sec;
+            timbuf.modtime = tv[1].tv_sec;
             err = f->ops.utime(filedesc->PosixPath, &timbuf);
             Result = fsp_fuse_ntstatus_from_errno(f->env, err);
         }