Windows port - add fdatasync()

src/win/sb_win_posix.c

@@ -20,6 +20,7 @@
 #include <time.h>
 #include <io.h>
 #include <string.h>
+#include <winternl.h>
 #include "sb_win_posix.h"
 
 /*
@@ -164,3 +165,52 @@ const char* sb_win_basename(const char* path)
  return path;
 }
 
+
+/*
+ Windows' "fdatasync", NtFlushBuffersFileEx.
+ Has to be loaded dynamically, not in officional headers
+*/
+typedef NTSTATUS(WINAPI *NtFlushBuffersFileEx_func)(
+ HANDLE FileHandle, ULONG Flags, PVOID Parameters, ULONG ParametersSize,
+ PIO_STATUS_BLOCK IoStatusBlock);
+static NtFlushBuffersFileEx_func my_NtFlushBuffersFileEx;
+static BOOL disable_datasync;
+
+BOOL CALLBACK init_nt_flush_file_buffers_ex(PINIT_ONCE initOnce, PVOID Parameter,
+ PVOID *Context)
+{
+ my_NtFlushBuffersFileEx= (NtFlushBuffersFileEx_func) 
+ GetProcAddress( GetModuleHandle("ntdll"), "NtFlushBuffersFileEx");
+ if (!my_NtFlushBuffersFileEx)
+ disable_datasync= TRUE;
+ return TRUE;
+}
+
+int sb_win_fdatasync(int fd)
+{
+ static INIT_ONCE init_once= INIT_ONCE_STATIC_INIT;
+ InitOnceExecuteOnce(&init_once, init_nt_flush_file_buffers_ex, NULL, NULL);
+ HANDLE h = get_handle(fd);
+ if (h == NULL || h == INVALID_HANDLE_VALUE)
+ return -1;
+
+ if (!disable_datasync && my_NtFlushBuffersFileEx)
+ {
+ IO_STATUS_BLOCK iosb;
+ memset(&iosb, 0, sizeof(iosb));
+ NTSTATUS status= my_NtFlushBuffersFileEx(
+ h, FLUSH_FLAGS_FILE_DATA_SYNC_ONLY, NULL, 0, &iosb);
+ if (!status)
+ {
+ return 0;
+ }
+ }
+ /* Fallback to full sync. */
+ if (FlushFileBuffers(h))
+ {
+ disable_datasync = TRUE;
+ return 0;
+ }
+ errno = EINVAL;
+ return -1;
+}

src/win/sb_win_posix.h

@@ -42,6 +42,7 @@ sb_win_signal_t sb_win_signal(int sig, sb_win_signal_t);
 /* pread()/write() */
 ssize_t sb_win_pread(int fd, void* buf, size_t count, unsigned long long offset);
 ssize_t sb_win_pwrite(int fd, const void* buf, size_t count, unsigned long long offset);
+int sb_win_fdatasync(int fd);
 
 /* clock_gettime() */
 #ifndef HAVE_CLOCK_GETTIME
@@ -86,4 +87,8 @@ const char* sb_win_basename(const char* path);
 #ifndef HAVE_LIBGEN_H
 #define basename(path) sb_win_basename(path)
 #endif
+#ifndef HAVE_FDATASYNC
+#define HAVE_FDATASYNC
+#define fdatasync(fd) sb_win_fdatasync(fd)
+#endif
 #endif