From df2b472cd95d0aba99451b991da1af8c8f9d4e59 Mon Sep 17 00:00:00 2001
From: Cyril Cleaud <cyril.cleaud@gmail.com>
Date: Thu, 26 Jun 2014 22:59:17 -0700
Subject: [PATCH] Add umask and rename compatibility wrappers for Windows

umask() doesn't exist on Windows and is thus a no-op.

rename() only works if the destination doesn't already exist,
so we must unlink before renaming.
---
 commands.cpp   |  2 +-
 key.cpp        |  4 ++--
 util-unix.cpp  | 16 +++++++++++++---
 util-win32.cpp | 13 +++++++++++++
 util.hpp       |  3 +++
 5 files changed, 32 insertions(+), 6 deletions(-)

diff --git a/commands.cpp b/commands.cpp
index 9519eb1..5472766 100644
--- a/commands.cpp
+++ b/commands.cpp
@@ -765,7 +765,7 @@ int migrate_key (int argc, char** argv)
 				return 1;
 			}
 
-			if (rename(new_key_file_name.c_str(), key_file_name) == -1) {
+			if (util_rename(new_key_file_name.c_str(), key_file_name) == -1) {
 				std::clog << "Error: " << key_file_name << ": " << strerror(errno) << std::endl;
 				unlink(new_key_file_name.c_str());
 				return 1;
diff --git a/key.cpp b/key.cpp
index 508ff8d..05e059c 100644
--- a/key.cpp
+++ b/key.cpp
@@ -134,9 +134,9 @@ bool		Key_file::load_from_file (const char* key_file_name)
 
 bool		Key_file::store_to_file (const char* key_file_name) const
 {
-	mode_t		old_umask = umask(0077); // make sure key file is protected (TODO: Windows compat)
+	mode_t		old_umask = util_umask(0077); // make sure key file is protected
 	std::ofstream	key_file_out(key_file_name, std::fstream::binary);
-	umask(old_umask);
+	util_umask(old_umask);
 	if (!key_file_out) {
 		return false;
 	}
diff --git a/util-unix.cpp b/util-unix.cpp
index 7f92a58..1224e66 100644
--- a/util-unix.cpp
+++ b/util-unix.cpp
@@ -69,14 +69,14 @@ void	temp_fstream::open (std::ios_base::openmode mode)
 	char*			path = &path_buffer[0];
 	std::strcpy(path, tmpdir);
 	std::strcpy(path + tmpdir_len, "/git-crypt.XXXXXX");
-	mode_t			old_umask = umask(0077);
+	mode_t			old_umask = util_umask(0077);
 	int			fd = mkstemp(path);
 	if (fd == -1) {
 		int		mkstemp_errno = errno;
-		umask(old_umask);
+		util_umask(old_umask);
 		throw System_error("mkstemp", "", mkstemp_errno);
 	}
-	umask(old_umask);
+	util_umask(old_umask);
 	std::fstream::open(path, mode);
 	if (!std::fstream::is_open()) {
 		unlink(path);
@@ -277,3 +277,13 @@ bool successful_exit (int status)
 static void	init_std_streams_platform ()
 {
 }
+
+mode_t util_umask (mode_t mode)
+{
+	return umask(mode);
+}
+
+int util_rename (const char* from, const char* to)
+{
+	return rename(from, to);
+}
diff --git a/util-win32.cpp b/util-win32.cpp
index e852e52..b0d20d1 100644
--- a/util-win32.cpp
+++ b/util-win32.cpp
@@ -325,3 +325,16 @@ static void	init_std_streams_platform ()
 	_setmode(_fileno(stdin), _O_BINARY);
 	_setmode(_fileno(stdout), _O_BINARY);
 }
+
+mode_t util_umask (mode_t mode)
+{
+	// Not available in Windows and function not always defined in Win32 environments
+	return 0;
+}
+
+int util_rename (const char* from, const char* to)
+{
+	// On Windows OS, it is necessary to ensure target file doesn't exist
+	unlink(to);
+	return rename(from, to);
+}
diff --git a/util.hpp b/util.hpp
index 7cae193..cf23771 100644
--- a/util.hpp
+++ b/util.hpp
@@ -35,6 +35,7 @@
 #include <ios>
 #include <iosfwd>
 #include <stdint.h>
+#include <sys/types.h>
 #include <fstream>
 #include <vector>
 
@@ -69,6 +70,8 @@ void		store_be32 (unsigned char*, uint32_t);
 bool		read_be32 (std::istream& in, uint32_t&);
 void		write_be32 (std::ostream& out, uint32_t);
 void		init_std_streams ();
+mode_t		util_umask (mode_t);
+int		util_rename (const char*, const char*);
 
 #endif