From 3d59383fed00ef4009e1adb26753ca94d80b5b1b Mon Sep 17 00:00:00 2001
From: Johannes Schindelin <johannes.schindelin@gmx.de>
Date: Mon, 12 Oct 2015 19:24:05 +0000
Subject: [PATCH 01/25] getpwuid(mingw): initialize the structure only once

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
---
 compat/mingw.c | 25 ++++++++++++++++++-------
 1 file changed, 18 insertions(+), 7 deletions(-)

diff --git a/compat/mingw.c b/compat/mingw.c
index a67872babf..e37c2c5130 100644
--- a/compat/mingw.c
+++ b/compat/mingw.c
@@ -1733,16 +1733,27 @@ int mingw_getpagesize(void)
 
 struct passwd *getpwuid(int uid)
 {
+	static unsigned initialized;
 	static char user_name[100];
-	static struct passwd p;
+	static struct passwd *p;
+	DWORD len;
 
-	DWORD len = sizeof(user_name);
-	if (!GetUserName(user_name, &len))
+	if (initialized)
+		return p;
+
+	len = sizeof(user_name);
+	if (!GetUserName(user_name, &len)) {
+		initialized = 1;
 		return NULL;
-	p.pw_name = user_name;
-	p.pw_gecos = "unknown";
-	p.pw_dir = NULL;
-	return &p;
+	}
+
+	p = xmalloc(sizeof(*p));
+	p->pw_name = user_name;
+	p->pw_gecos = "unknown";
+	p->pw_dir = NULL;
+
+	initialized = 1;
+	return p;
 }
 
 static HANDLE timer_event;

From cbeca6bee2ff44af756cf8d0839243d21076c312 Mon Sep 17 00:00:00 2001
From: Johannes Schindelin <johannes.schindelin@gmx.de>
Date: Tue, 13 Oct 2015 10:05:53 +0000
Subject: [PATCH 02/25] getpwuid(mingw): provide a better default for the user
 name

We do have the excellent GetUserInfoEx() function to obtain more
detailed information of the current user (if the user is part of a
Windows domain); Let's use it.

Suggested by Lutz Roeder.

To avoid the cost of loading Secur32.dll (even lazily, loading DLLs
takes a non-neglibile amount of time), we use the established technique
to load DLLs only when, and if, needed.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
---
 compat/mingw.c | 32 +++++++++++++++++++++++++++++++-
 1 file changed, 31 insertions(+), 1 deletion(-)

diff --git a/compat/mingw.c b/compat/mingw.c
index e37c2c5130..7864ae378d 100644
--- a/compat/mingw.c
+++ b/compat/mingw.c
@@ -5,6 +5,7 @@
 #include "../strbuf.h"
 #include "../run-command.h"
 #include "../cache.h"
+#include "win32/lazyload.h"
 
 #define HCAST(type, handle) ((type)(intptr_t)handle)
 
@@ -1731,6 +1732,33 @@ int mingw_getpagesize(void)
 	return si.dwAllocationGranularity;
 }
 
+/* See https://msdn.microsoft.com/en-us/library/windows/desktop/ms724435.aspx */
+enum EXTENDED_NAME_FORMAT {
+	NameDisplay = 3,
+	NameUserPrincipal = 8
+};
+
+static char *get_extended_user_info(enum EXTENDED_NAME_FORMAT type)
+{
+	DECLARE_PROC_ADDR(secur32.dll, BOOL, GetUserNameExW,
+		enum EXTENDED_NAME_FORMAT, LPCWSTR, PULONG);
+	static wchar_t wbuffer[1024];
+	DWORD len;
+
+	if (!INIT_PROC_ADDR(GetUserNameExW))
+		return NULL;
+
+	len = ARRAY_SIZE(wbuffer);
+	if (GetUserNameExW(type, wbuffer, &len)) {
+		char *converted = xmalloc((len *= 3));
+		if (xwcstoutf(converted, wbuffer, len) >= 0)
+			return converted;
+		free(converted);
+	}
+
+	return NULL;
+}
+
 struct passwd *getpwuid(int uid)
 {
 	static unsigned initialized;
@@ -1749,7 +1777,9 @@ struct passwd *getpwuid(int uid)
 
 	p = xmalloc(sizeof(*p));
 	p->pw_name = user_name;
-	p->pw_gecos = "unknown";
+	p->pw_gecos = get_extended_user_info(NameDisplay);
+	if (!p->pw_gecos)
+		p->pw_gecos = "unknown";
 	p->pw_dir = NULL;
 
 	initialized = 1;

From 4401b3b7bd2ab23008a6c1bd149edddbb8a7d8ea Mon Sep 17 00:00:00 2001
From: Johannes Schindelin <johannes.schindelin@gmx.de>
Date: Tue, 13 Oct 2015 10:36:52 +0000
Subject: [PATCH 03/25] mingw: use domain information for default email

When a user is registered in a Windows domain, it is really easy to
obtain the email address. So let's do that.

Suggested by Lutz Roeder.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
---
 compat/mingw.c    | 5 +++++
 compat/mingw.h    | 2 ++
 git-compat-util.h | 4 ++++
 ident.c           | 3 +++
 4 files changed, 14 insertions(+)

diff --git a/compat/mingw.c b/compat/mingw.c
index 7864ae378d..3497a24be2 100644
--- a/compat/mingw.c
+++ b/compat/mingw.c
@@ -1759,6 +1759,11 @@ static char *get_extended_user_info(enum EXTENDED_NAME_FORMAT type)
 	return NULL;
 }
 
+char *mingw_query_user_email(void)
+{
+	return get_extended_user_info(NameUserPrincipal);
+}
+
 struct passwd *getpwuid(int uid)
 {
 	static unsigned initialized;
diff --git a/compat/mingw.h b/compat/mingw.h
index 571019d0bd..f31dcff2be 100644
--- a/compat/mingw.h
+++ b/compat/mingw.h
@@ -424,6 +424,8 @@ static inline void convert_slashes(char *path)
 int mingw_offset_1st_component(const char *path);
 #define offset_1st_component mingw_offset_1st_component
 #define PATH_SEP ';'
+extern char *mingw_query_user_email(void);
+#define query_user_email mingw_query_user_email
 #if !defined(__MINGW64_VERSION_MAJOR) && (!defined(_MSC_VER) || _MSC_VER < 1800)
 #define PRIuMAX "I64u"
 #define PRId64 "I64d"
diff --git a/git-compat-util.h b/git-compat-util.h
index 76cd42bd63..7c2dfbeba4 100644
--- a/git-compat-util.h
+++ b/git-compat-util.h
@@ -378,6 +378,10 @@ static inline char *git_find_last_dir_sep(const char *path)
 #define find_last_dir_sep git_find_last_dir_sep
 #endif
 
+#ifndef query_user_email
+#define query_user_email() NULL
+#endif
+
 #if defined(__HP_cc) && (__HP_cc >= 61000)
 #define NORETURN __attribute__((noreturn))
 #define NORETURN_PTR
diff --git a/ident.c b/ident.c
index 327abe557f..33bcf40644 100644
--- a/ident.c
+++ b/ident.c
@@ -168,6 +168,9 @@ const char *ident_default_email(void)
 			strbuf_addstr(&git_default_email, email);
 			committer_ident_explicitly_given |= IDENT_MAIL_GIVEN;
 			author_ident_explicitly_given |= IDENT_MAIL_GIVEN;
+		} else if ((email = query_user_email()) && email[0]) {
+			strbuf_addstr(&git_default_email, email);
+			free((char *)email);
 		} else
 			copy_email(xgetpwuid_self(&default_email_is_bogus),
 				   &git_default_email, &default_email_is_bogus);

From 22030d6f09af386b3ffb6a2a04ffc2a32e16f647 Mon Sep 17 00:00:00 2001
From: Johannes Schindelin <johannes.schindelin@gmx.de>
Date: Tue, 10 Jan 2017 23:14:20 +0100
Subject: [PATCH 04/25] winansi: simplify loading the GetCurrentConsoleFontEx()
 function

We introduced helper macros to simplify loading functions dynamically.
Might just as well use them.

Signed-off-by: Karsten Blees <blees@dcon.de>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
---
 compat/winansi.c | 14 +++++---------
 1 file changed, 5 insertions(+), 9 deletions(-)

diff --git a/compat/winansi.c b/compat/winansi.c
index a11a0f16d2..be2ad5d41d 100644
--- a/compat/winansi.c
+++ b/compat/winansi.c
@@ -7,6 +7,7 @@
 #include <wingdi.h>
 #include <winreg.h>
 #include "win32.h"
+#include "win32/lazyload.h"
 
 static int fd_is_interactive[3] = { 0, 0, 0 };
 #define FD_CONSOLE 0x1
@@ -41,26 +42,21 @@ typedef struct _CONSOLE_FONT_INFOEX {
 #endif
 #endif
 
-typedef BOOL (WINAPI *PGETCURRENTCONSOLEFONTEX)(HANDLE, BOOL,
-		PCONSOLE_FONT_INFOEX);
-
 static void warn_if_raster_font(void)
 {
 	DWORD fontFamily = 0;
-	PGETCURRENTCONSOLEFONTEX pGetCurrentConsoleFontEx;
+	DECLARE_PROC_ADDR(kernel32.dll, BOOL, GetCurrentConsoleFontEx,
+			HANDLE, BOOL, PCONSOLE_FONT_INFOEX);
 
 	/* don't bother if output was ascii only */
 	if (!non_ascii_used)
 		return;
 
 	/* GetCurrentConsoleFontEx is available since Vista */
-	pGetCurrentConsoleFontEx = (PGETCURRENTCONSOLEFONTEX) GetProcAddress(
-			GetModuleHandle("kernel32.dll"),
-			"GetCurrentConsoleFontEx");
-	if (pGetCurrentConsoleFontEx) {
+	if (INIT_PROC_ADDR(GetCurrentConsoleFontEx)) {
 		CONSOLE_FONT_INFOEX cfi;
 		cfi.cbSize = sizeof(cfi);
-		if (pGetCurrentConsoleFontEx(console, 0, &cfi))
+		if (GetCurrentConsoleFontEx(console, 0, &cfi))
 			fontFamily = cfi.FontFamily;
 	} else {
 		/* pre-Vista: check default console font in registry */

From f3f7e1beba35e2d1741c89c5d86da6eb2c2e55a0 Mon Sep 17 00:00:00 2001
From: Johannes Schindelin <johannes.schindelin@gmx.de>
Date: Tue, 10 Jan 2017 23:14:20 +0100
Subject: [PATCH 05/25] mingw: simplify loading the CreadHardLinkW() function

We introduced helper macros to simplify loading functions dynamically.
Might just as well use them.

Signed-off-by: Karsten Blees <blees@dcon.de>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
---
 compat/mingw.c | 20 +++++++-------------
 1 file changed, 7 insertions(+), 13 deletions(-)

diff --git a/compat/mingw.c b/compat/mingw.c
index 40907a1fd0..a2db8fd33a 100644
--- a/compat/mingw.c
+++ b/compat/mingw.c
@@ -2087,24 +2087,18 @@ int mingw_raise(int sig)
 
 int link(const char *oldpath, const char *newpath)
 {
-	typedef BOOL (WINAPI *T)(LPCWSTR, LPCWSTR, LPSECURITY_ATTRIBUTES);
-	static T create_hard_link = NULL;
+	DECLARE_PROC_ADDR(kernel32.dll, BOOL, CreateHardLinkW,
+			LPCWSTR, LPCWSTR, LPSECURITY_ATTRIBUTES);
 	wchar_t woldpath[MAX_LONG_PATH], wnewpath[MAX_LONG_PATH];
+
+	if (!INIT_PROC_ADDR(CreateHardLinkW))
+		return -1;
+
 	if (xutftowcs_long_path(woldpath, oldpath) < 0 ||
 	    xutftowcs_long_path(wnewpath, newpath) < 0)
 		return -1;
 
-	if (!create_hard_link) {
-		create_hard_link = (T) GetProcAddress(
-			GetModuleHandle("kernel32.dll"), "CreateHardLinkW");
-		if (!create_hard_link)
-			create_hard_link = (T)-1;
-	}
-	if (create_hard_link == (T)-1) {
-		errno = ENOSYS;
-		return -1;
-	}
-	if (!create_hard_link(wnewpath, woldpath, NULL)) {
+	if (!CreateHardLinkW(wnewpath, woldpath, NULL)) {
 		errno = err_win_to_posix(GetLastError());
 		return -1;
 	}

From bc7f4fcf6504f6e17925c6fb19c6cf93bf9d5198 Mon Sep 17 00:00:00 2001
From: Karsten Blees <blees@dcon.de>
Date: Mon, 11 May 2015 19:54:23 +0200
Subject: [PATCH 06/25] strbuf_readlink: don't call readlink twice if hint is
 the exact link size

strbuf_readlink() calls readlink() twice if the hint argument specifies the
exact size of the link target (e.g. by passing stat.st_size as returned by
lstat()). This is necessary because 'readlink(..., hint) == hint' could
mean that the buffer was too small.

Use hint + 1 as buffer size to prevent this.

Signed-off-by: Karsten Blees <blees@dcon.de>
---
 strbuf.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/strbuf.c b/strbuf.c
index 0759590b3e..6f9e908ded 100644
--- a/strbuf.c
+++ b/strbuf.c
@@ -446,12 +446,12 @@ int strbuf_readlink(struct strbuf *sb, const char *path, size_t hint)
 	while (hint < STRBUF_MAXLINK) {
 		int len;
 
-		strbuf_grow(sb, hint);
-		len = readlink(path, sb->buf, hint);
+		strbuf_grow(sb, hint + 1);
+		len = readlink(path, sb->buf, hint + 1);
 		if (len < 0) {
 			if (errno != ERANGE)
 				break;
-		} else if (len < hint) {
+		} else if (len <= hint) {
 			strbuf_setlen(sb, len);
 			return 0;
 		}

From fe9b593c58671b3009171d9285f0f9e4d20145cc Mon Sep 17 00:00:00 2001
From: Karsten Blees <blees@dcon.de>
Date: Mon, 11 May 2015 22:15:40 +0200
Subject: [PATCH 07/25] strbuf_readlink: support link targets that exceed
 PATH_MAX

strbuf_readlink() refuses to read link targets that exceed PATH_MAX (even
if a sufficient size was specified by the caller).

As some platforms support longer paths, remove this restriction (similar
to strbuf_getcwd()).

Signed-off-by: Karsten Blees <blees@dcon.de>
---
 strbuf.c | 7 +------
 1 file changed, 1 insertion(+), 6 deletions(-)

diff --git a/strbuf.c b/strbuf.c
index 6f9e908ded..b8b954ecfe 100644
--- a/strbuf.c
+++ b/strbuf.c
@@ -434,8 +434,6 @@ ssize_t strbuf_write(struct strbuf *sb, FILE *f)
 }
 
 
-#define STRBUF_MAXLINK (2*PATH_MAX)
-
 int strbuf_readlink(struct strbuf *sb, const char *path, size_t hint)
 {
 	size_t oldalloc = sb->alloc;
@@ -443,7 +441,7 @@ int strbuf_readlink(struct strbuf *sb, const char *path, size_t hint)
 	if (hint < 32)
 		hint = 32;
 
-	while (hint < STRBUF_MAXLINK) {
+	for (;; hint *= 2) {
 		int len;
 
 		strbuf_grow(sb, hint + 1);
@@ -455,9 +453,6 @@ int strbuf_readlink(struct strbuf *sb, const char *path, size_t hint)
 			strbuf_setlen(sb, len);
 			return 0;
 		}
-
-		/* .. the buffer was too small - try again */
-		hint *= 2;
 	}
 	if (oldalloc == 0)
 		strbuf_release(sb);

From f4a1ab1b1a841e4feb28a65363a74a70a4a34861 Mon Sep 17 00:00:00 2001
From: Karsten Blees <blees@dcon.de>
Date: Mon, 11 May 2015 19:58:14 +0200
Subject: [PATCH 08/25] lockfile.c: use is_dir_sep() instead of hardcoded '/'
 checks

Signed-off-by: Karsten Blees <blees@dcon.de>
---
 lockfile.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/lockfile.c b/lockfile.c
index efcb7d7dfe..da11a32ff6 100644
--- a/lockfile.c
+++ b/lockfile.c
@@ -17,14 +17,14 @@ static void trim_last_path_component(struct strbuf *path)
 	int i = path->len;
 
 	/* back up past trailing slashes, if any */
-	while (i && path->buf[i - 1] == '/')
+	while (i && is_dir_sep(path->buf[i - 1]))
 		i--;
 
 	/*
 	 * then go backwards until a slash, or the beginning of the
 	 * string
 	 */
-	while (i && path->buf[i - 1] != '/')
+	while (i && !is_dir_sep(path->buf[i - 1]))
 		i--;
 
 	strbuf_setlen(path, i);

From f9838f5f7a93b0736afb4fe40bc48c92b9a5d1a0 Mon Sep 17 00:00:00 2001
From: Karsten Blees <blees@dcon.de>
Date: Tue, 12 May 2015 11:09:01 +0200
Subject: [PATCH 09/25] Win32: don't call GetFileAttributes twice in
 mingw_lstat()

GetFileAttributes cannot handle paths with trailing dir separator. The
current [l]stat implementation calls GetFileAttributes twice if the path
has trailing slashes (first with the original path passed to [l]stat, and
and a second time with a path copy with trailing '/' removed).

With Unicode conversion, we get the length of the path for free and also
have a (wide char) buffer that can be modified.

Remove trailing directory separators before calling the Win32 API.

Signed-off-by: Karsten Blees <blees@dcon.de>
---
 compat/mingw.c | 48 ++++++++++++------------------------------------
 1 file changed, 12 insertions(+), 36 deletions(-)

diff --git a/compat/mingw.c b/compat/mingw.c
index a2db8fd33a..48e3f82184 100644
--- a/compat/mingw.c
+++ b/compat/mingw.c
@@ -609,9 +609,18 @@ static int do_lstat(int follow, const char *file_name, struct stat *buf)
 {
 	WIN32_FILE_ATTRIBUTE_DATA fdata;
 	wchar_t wfilename[MAX_LONG_PATH];
-	if (xutftowcs_long_path(wfilename, file_name) < 0)
+	int wlen = xutftowcs_long_path(wfilename, file_name);
+	if (wlen < 0)
 		return -1;
 
+	/* strip trailing '/', or GetFileAttributes will fail */
+	while (wlen && is_dir_sep(wfilename[wlen - 1]))
+		wfilename[--wlen] = 0;
+	if (!wlen) {
+		errno = ENOENT;
+		return -1;
+	}
+
 	if (GetFileAttributesExW(wfilename, GetFileExInfoStandard, &fdata)) {
 		buf->st_ino = 0;
 		buf->st_gid = 0;
@@ -671,48 +680,15 @@ static int do_lstat(int follow, const char *file_name, struct stat *buf)
 	return -1;
 }
 
-/* We provide our own lstat/fstat functions, since the provided
- * lstat/fstat functions are so slow. These stat functions are
- * tailored for Git's usage (read: fast), and are not meant to be
- * complete. Note that Git stat()s are redirected to mingw_lstat()
- * too, since Windows doesn't really handle symlinks that well.
- */
-static int do_stat_internal(int follow, const char *file_name, struct stat *buf)
-{
-	int namelen;
-	char alt_name[MAX_LONG_PATH];
-
-	if (!do_lstat(follow, file_name, buf))
-		return 0;
-
-	/* if file_name ended in a '/', Windows returned ENOENT;
-	 * try again without trailing slashes
-	 */
-	if (errno != ENOENT)
-		return -1;
-
-	namelen = strlen(file_name);
-	if (namelen && file_name[namelen-1] != '/')
-		return -1;
-	while (namelen && file_name[namelen-1] == '/')
-		--namelen;
-	if (!namelen || namelen >= MAX_LONG_PATH)
-		return -1;
-
-	memcpy(alt_name, file_name, namelen);
-	alt_name[namelen] = 0;
-	return do_lstat(follow, alt_name, buf);
-}
-
 int (*lstat)(const char *file_name, struct stat *buf) = mingw_lstat;
 
 int mingw_lstat(const char *file_name, struct stat *buf)
 {
-	return do_stat_internal(0, file_name, buf);
+	return do_lstat(0, file_name, buf);
 }
 int mingw_stat(const char *file_name, struct stat *buf)
 {
-	return do_stat_internal(1, file_name, buf);
+	return do_lstat(1, file_name, buf);
 }
 
 int mingw_fstat(int fd, struct stat *buf)

From 355e0e2057b311d8a12fcfb42398214ad3309e40 Mon Sep 17 00:00:00 2001
From: Karsten Blees <blees@dcon.de>
Date: Sat, 16 May 2015 01:18:14 +0200
Subject: [PATCH 10/25] Win32: implement stat() with symlink support

With respect to symlinks, the current stat() implementation is almost the
same as lstat(): except for the file type (st_mode & S_IFMT), it returns
information about the link rather than the target.

Implement stat by opening the file with as little permissions as possible
and calling GetFileInformationByHandle on it. This way, all link resoltion
is handled by the Windows file system layer.

If symlinks are disabled, use lstat() as before, but fail with ELOOP if a
symlink would have to be resolved.

Signed-off-by: Karsten Blees <blees@dcon.de>
---
 compat/mingw.c | 64 +++++++++++++++++++++++++++++++++++++-------------
 1 file changed, 48 insertions(+), 16 deletions(-)

diff --git a/compat/mingw.c b/compat/mingw.c
index 48e3f82184..20b470c286 100644
--- a/compat/mingw.c
+++ b/compat/mingw.c
@@ -686,16 +686,60 @@ int mingw_lstat(const char *file_name, struct stat *buf)
 {
 	return do_lstat(0, file_name, buf);
 }
+
+static int get_file_info_by_handle(HANDLE hnd, struct stat *buf)
+{
+	BY_HANDLE_FILE_INFORMATION fdata;
+	if (!GetFileInformationByHandle(hnd, &fdata)) {
+		errno = err_win_to_posix(GetLastError());
+		return -1;
+	}
+	buf->st_ino = 0;
+	buf->st_dev = buf->st_rdev = 0; /* not used by Git */
+	buf->st_gid = buf->st_uid = 0;
+	buf->st_nlink = 1;
+	buf->st_mode = file_attr_to_st_mode(fdata.dwFileAttributes);
+	buf->st_size = fdata.nFileSizeLow | (((off_t) fdata.nFileSizeHigh) << 32);
+	buf->st_atime = filetime_to_time_t(&(fdata.ftLastAccessTime));
+	buf->st_mtime = filetime_to_time_t(&(fdata.ftLastWriteTime));
+	buf->st_ctime = filetime_to_time_t(&(fdata.ftCreationTime));
+	return 0;
+}
+
 int mingw_stat(const char *file_name, struct stat *buf)
 {
-	return do_lstat(1, file_name, buf);
+	wchar_t wfile_name[MAX_LONG_PATH];
+	HANDLE hnd;
+	int result;
+
+	/* if symlinks are disabled, use lstat() (without following links) */
+	if (!has_symlinks) {
+		result = lstat(file_name, buf);
+		if (!result && S_ISLNK(buf->st_mode)) {
+			errno = ELOOP;
+			return -1;
+		}
+		return result;
+	}
+
+	/* otherwise just open the file and let Windows resolve the links */
+	if (xutftowcs_long_path(wfile_name, file_name) < 0)
+		return -1;
+	hnd = CreateFileW(wfile_name, 0,
+			FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE, NULL,
+			OPEN_EXISTING, FILE_FLAG_BACKUP_SEMANTICS, NULL);
+	if (hnd == INVALID_HANDLE_VALUE) {
+		errno = err_win_to_posix(GetLastError());
+		return -1;
+	}
+	result = get_file_info_by_handle(hnd, buf);
+	CloseHandle(hnd);
+	return result;
 }
 
 int mingw_fstat(int fd, struct stat *buf)
 {
 	HANDLE fh = (HANDLE)_get_osfhandle(fd);
-	BY_HANDLE_FILE_INFORMATION fdata;
-
 	if (fh == INVALID_HANDLE_VALUE) {
 		errno = EBADF;
 		return -1;
@@ -704,20 +748,8 @@ int mingw_fstat(int fd, struct stat *buf)
 	if (GetFileType(fh) != FILE_TYPE_DISK)
 		return _fstati64(fd, buf);
 
-	if (GetFileInformationByHandle(fh, &fdata)) {
-		buf->st_ino = 0;
-		buf->st_gid = 0;
-		buf->st_uid = 0;
-		buf->st_nlink = 1;
-		buf->st_mode = file_attr_to_st_mode(fdata.dwFileAttributes);
-		buf->st_size = fdata.nFileSizeLow |
-			(((off_t)fdata.nFileSizeHigh)<<32);
-		buf->st_dev = buf->st_rdev = 0; /* not used by Git */
-		buf->st_atime = filetime_to_time_t(&(fdata.ftLastAccessTime));
-		buf->st_mtime = filetime_to_time_t(&(fdata.ftLastWriteTime));
-		buf->st_ctime = filetime_to_time_t(&(fdata.ftCreationTime));
+	if (!get_file_info_by_handle(fh, buf))
 		return 0;
-	}
 	errno = EBADF;
 	return -1;
 }

From 22e630027213556773d0a9e18bfb4a6dc814801d Mon Sep 17 00:00:00 2001
From: Karsten Blees <blees@dcon.de>
Date: Tue, 12 May 2015 00:58:39 +0200
Subject: [PATCH 11/25] Win32: remove separate do_lstat() function

With the new mingw_stat() implementation, do_lstat() is only called from
mingw_lstat() (with follow == 0). Remove the extra function and the old
mingw_stat()-specific (follow == 1) logic.

Signed-off-by: Karsten Blees <blees@dcon.de>
---
 compat/mingw.c | 22 ++--------------------
 1 file changed, 2 insertions(+), 20 deletions(-)

diff --git a/compat/mingw.c b/compat/mingw.c
index 20b470c286..ddaafca808 100644
--- a/compat/mingw.c
+++ b/compat/mingw.c
@@ -598,14 +598,7 @@ static int has_valid_directory_prefix(wchar_t *wfilename)
 	return 1;
 }
 
-/* We keep the do_lstat code in a separate function to avoid recursion.
- * When a path ends with a slash, the stat will fail with ENOENT. In
- * this case, we strip the trailing slashes and stat again.
- *
- * If follow is true then act like stat() and report on the link
- * target. Otherwise report on the link itself.
- */
-static int do_lstat(int follow, const char *file_name, struct stat *buf)
+int mingw_lstat(const char *file_name, struct stat *buf)
 {
 	WIN32_FILE_ATTRIBUTE_DATA fdata;
 	wchar_t wfilename[MAX_LONG_PATH];
@@ -639,13 +632,7 @@ static int do_lstat(int follow, const char *file_name, struct stat *buf)
 			if (handle != INVALID_HANDLE_VALUE) {
 				if ((findbuf.dwFileAttributes & FILE_ATTRIBUTE_REPARSE_POINT) &&
 						(findbuf.dwReserved0 == IO_REPARSE_TAG_SYMLINK)) {
-					if (follow) {
-						char buffer[MAXIMUM_REPARSE_DATA_BUFFER_SIZE];
-						buf->st_size = readlink(file_name, buffer, MAXIMUM_REPARSE_DATA_BUFFER_SIZE);
-					} else {
-						buf->st_mode = S_IFLNK;
-					}
-					buf->st_mode |= S_IREAD;
+					buf->st_mode = S_IFLNK | S_IREAD;
 					if (!(findbuf.dwFileAttributes & FILE_ATTRIBUTE_READONLY))
 						buf->st_mode |= S_IWRITE;
 				}
@@ -682,11 +669,6 @@ static int do_lstat(int follow, const char *file_name, struct stat *buf)
 
 int (*lstat)(const char *file_name, struct stat *buf) = mingw_lstat;
 
-int mingw_lstat(const char *file_name, struct stat *buf)
-{
-	return do_lstat(0, file_name, buf);
-}
-
 static int get_file_info_by_handle(HANDLE hnd, struct stat *buf)
 {
 	BY_HANDLE_FILE_INFORMATION fdata;

From 7ff2406079ac3eb360c74844cfadf06481d457f1 Mon Sep 17 00:00:00 2001
From: Karsten Blees <blees@dcon.de>
Date: Sun, 24 May 2015 00:17:56 +0200
Subject: [PATCH 12/25] Win32: let mingw_lstat() error early upon problems with
 reparse points

When obtaining lstat information for reparse points, we need to call
FindFirstFile() in addition to GetFileInformationEx() to obtain the type
of the reparse point (symlink, mount point etc.). However, currently there
is no error handling whatsoever if FindFirstFile() fails.

Call FindFirstFile() before modifying the stat *buf output parameter and
error out if the call fails.

Note: The FindFirstFile() return value includes all the data that we get
from GetFileAttributesEx(), so we could replace GetFileAttributesEx() with
FindFirstFile(). We don't do that because GetFileAttributesEx() is about
twice as fast for single files. I.e. we only pay the extra cost of calling
FindFirstFile() in the rare case that we encounter a reparse point.

Note: The indentation of the remaining reparse point code will be fixed in
the next patch.

Signed-off-by: Karsten Blees <blees@dcon.de>
---
 compat/mingw.c | 14 +++++++++-----
 1 file changed, 9 insertions(+), 5 deletions(-)

diff --git a/compat/mingw.c b/compat/mingw.c
index ddaafca808..149f825d62 100644
--- a/compat/mingw.c
+++ b/compat/mingw.c
@@ -601,6 +601,7 @@ static int has_valid_directory_prefix(wchar_t *wfilename)
 int mingw_lstat(const char *file_name, struct stat *buf)
 {
 	WIN32_FILE_ATTRIBUTE_DATA fdata;
+	WIN32_FIND_DATAW findbuf;
 	wchar_t wfilename[MAX_LONG_PATH];
 	int wlen = xutftowcs_long_path(wfilename, file_name);
 	if (wlen < 0)
@@ -615,6 +616,13 @@ int mingw_lstat(const char *file_name, struct stat *buf)
 	}
 
 	if (GetFileAttributesExW(wfilename, GetFileExInfoStandard, &fdata)) {
+		/* for reparse points, use FindFirstFile to get the reparse tag */
+		if (fdata.dwFileAttributes & FILE_ATTRIBUTE_REPARSE_POINT) {
+			HANDLE handle = FindFirstFileW(wfilename, &findbuf);
+			if (handle == INVALID_HANDLE_VALUE)
+				goto error;
+			FindClose(handle);
+		}
 		buf->st_ino = 0;
 		buf->st_gid = 0;
 		buf->st_uid = 0;
@@ -627,20 +635,16 @@ int mingw_lstat(const char *file_name, struct stat *buf)
 		buf->st_mtime = filetime_to_time_t(&(fdata.ftLastWriteTime));
 		buf->st_ctime = filetime_to_time_t(&(fdata.ftCreationTime));
 		if (fdata.dwFileAttributes & FILE_ATTRIBUTE_REPARSE_POINT) {
-			WIN32_FIND_DATAW findbuf;
-			HANDLE handle = FindFirstFileW(wfilename, &findbuf);
-			if (handle != INVALID_HANDLE_VALUE) {
 				if ((findbuf.dwFileAttributes & FILE_ATTRIBUTE_REPARSE_POINT) &&
 						(findbuf.dwReserved0 == IO_REPARSE_TAG_SYMLINK)) {
 					buf->st_mode = S_IFLNK | S_IREAD;
 					if (!(findbuf.dwFileAttributes & FILE_ATTRIBUTE_READONLY))
 						buf->st_mode |= S_IWRITE;
 				}
-				FindClose(handle);
-			}
 		}
 		return 0;
 	}
+error:
 	switch (GetLastError()) {
 	case ERROR_ACCESS_DENIED:
 	case ERROR_SHARING_VIOLATION:

From 00c09a8b936c525d87854bc530dd9d51063ceec1 Mon Sep 17 00:00:00 2001
From: Johannes Schindelin <johannes.schindelin@gmx.de>
Date: Tue, 10 Jan 2017 23:21:56 +0100
Subject: [PATCH 13/25] Win32: teach fscache and dirent about symlinks

Move S_IFLNK detection to file_attr_to_st_mode() and reuse it in fscache.

Implement DT_LNK detection in dirent.c and the fscache readdir version.

Signed-off-by: Karsten Blees <blees@dcon.de>
---
 compat/mingw.c         | 13 +++----------
 compat/win32.h         |  6 ++++--
 compat/win32/dirent.c  |  5 ++++-
 compat/win32/fscache.c |  6 ++++--
 4 files changed, 15 insertions(+), 15 deletions(-)

diff --git a/compat/mingw.c b/compat/mingw.c
index 149f825d62..5cc1b58461 100644
--- a/compat/mingw.c
+++ b/compat/mingw.c
@@ -627,21 +627,14 @@ int mingw_lstat(const char *file_name, struct stat *buf)
 		buf->st_gid = 0;
 		buf->st_uid = 0;
 		buf->st_nlink = 1;
-		buf->st_mode = file_attr_to_st_mode(fdata.dwFileAttributes);
+		buf->st_mode = file_attr_to_st_mode(fdata.dwFileAttributes,
+				findbuf.dwReserved0);
 		buf->st_size = fdata.nFileSizeLow |
 			(((off_t)fdata.nFileSizeHigh)<<32);
 		buf->st_dev = buf->st_rdev = 0; /* not used by Git */
 		buf->st_atime = filetime_to_time_t(&(fdata.ftLastAccessTime));
 		buf->st_mtime = filetime_to_time_t(&(fdata.ftLastWriteTime));
 		buf->st_ctime = filetime_to_time_t(&(fdata.ftCreationTime));
-		if (fdata.dwFileAttributes & FILE_ATTRIBUTE_REPARSE_POINT) {
-				if ((findbuf.dwFileAttributes & FILE_ATTRIBUTE_REPARSE_POINT) &&
-						(findbuf.dwReserved0 == IO_REPARSE_TAG_SYMLINK)) {
-					buf->st_mode = S_IFLNK | S_IREAD;
-					if (!(findbuf.dwFileAttributes & FILE_ATTRIBUTE_READONLY))
-						buf->st_mode |= S_IWRITE;
-				}
-		}
 		return 0;
 	}
 error:
@@ -684,7 +677,7 @@ static int get_file_info_by_handle(HANDLE hnd, struct stat *buf)
 	buf->st_dev = buf->st_rdev = 0; /* not used by Git */
 	buf->st_gid = buf->st_uid = 0;
 	buf->st_nlink = 1;
-	buf->st_mode = file_attr_to_st_mode(fdata.dwFileAttributes);
+	buf->st_mode = file_attr_to_st_mode(fdata.dwFileAttributes, 0);
 	buf->st_size = fdata.nFileSizeLow | (((off_t) fdata.nFileSizeHigh) << 32);
 	buf->st_atime = filetime_to_time_t(&(fdata.ftLastAccessTime));
 	buf->st_mtime = filetime_to_time_t(&(fdata.ftLastWriteTime));
diff --git a/compat/win32.h b/compat/win32.h
index a97e880757..671bcc81f9 100644
--- a/compat/win32.h
+++ b/compat/win32.h
@@ -6,10 +6,12 @@
 #include <windows.h>
 #endif
 
-static inline int file_attr_to_st_mode (DWORD attr)
+static inline int file_attr_to_st_mode (DWORD attr, DWORD tag)
 {
 	int fMode = S_IREAD;
-	if (attr & FILE_ATTRIBUTE_DIRECTORY)
+	if ((attr & FILE_ATTRIBUTE_REPARSE_POINT) && tag == IO_REPARSE_TAG_SYMLINK)
+		fMode |= S_IFLNK;
+	else if (attr & FILE_ATTRIBUTE_DIRECTORY)
 		fMode |= S_IFDIR;
 	else
 		fMode |= S_IFREG;
diff --git a/compat/win32/dirent.c b/compat/win32/dirent.c
index b3bd8d7af7..8c654d722b 100644
--- a/compat/win32/dirent.c
+++ b/compat/win32/dirent.c
@@ -16,7 +16,10 @@ static inline void finddata2dirent(struct dirent *ent, WIN32_FIND_DATAW *fdata)
 	xwcstoutf(ent->d_name, fdata->cFileName, MAX_PATH * 3);
 
 	/* Set file type, based on WIN32_FIND_DATA */
-	if (fdata->dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY)
+	if ((fdata->dwFileAttributes & FILE_ATTRIBUTE_REPARSE_POINT)
+			&& fdata->dwReserved0 == IO_REPARSE_TAG_SYMLINK)
+		ent->d_type = DT_LNK;
+	else if (fdata->dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY)
 		ent->d_type = DT_DIR;
 	else
 		ent->d_type = DT_REG;
diff --git a/compat/win32/fscache.c b/compat/win32/fscache.c
index 162fbed09b..f028aae88d 100644
--- a/compat/win32/fscache.c
+++ b/compat/win32/fscache.c
@@ -149,7 +149,8 @@ static struct fsentry *fseentry_create_entry(struct fsentry *list,
 
 	fse = fsentry_alloc(list, buf, len);
 
-	fse->st_mode = file_attr_to_st_mode(fdata->dwFileAttributes);
+	fse->st_mode = file_attr_to_st_mode(fdata->dwFileAttributes,
+			fdata->dwReserved0);
 	fse->st_size = (((off64_t) (fdata->nFileSizeHigh)) << 32)
 			| fdata->nFileSizeLow;
 	fse->st_atime = filetime_to_time_t(&(fdata->ftLastAccessTime));
@@ -442,7 +443,8 @@ static struct dirent *fscache_readdir(DIR *base_dir)
 	if (!next)
 		return NULL;
 	dir->pfsentry = next;
-	dir->dirent.d_type = S_ISDIR(next->st_mode) ? DT_DIR : DT_REG;
+	dir->dirent.d_type = S_ISREG(next->st_mode) ? DT_REG :
+			S_ISDIR(next->st_mode) ? DT_DIR : DT_LNK;
 	dir->dirent.d_name = (char*) next->name;
 	return &(dir->dirent);
 }

From 2c23ac6eb1eaaf69fd6381522a32f2ae402b2bbd Mon Sep 17 00:00:00 2001
From: Karsten Blees <blees@dcon.de>
Date: Sat, 16 May 2015 01:11:37 +0200
Subject: [PATCH 14/25] Win32: lstat(): return adequate stat.st_size for
 symlinks

Git typically doesn't trust the stat.st_size member of symlinks (e.g. see
strbuf_readlink()). However, some functions take shortcuts if st_size is 0
(e.g. diff_populate_filespec()).

In mingw_lstat() and fscache_lstat(), make sure to return an adequate size.

The extra overhead of opening and reading the reparse point to calculate
the exact size is not necessary, as git doesn't rely on the value anyway.

Signed-off-by: Karsten Blees <blees@dcon.de>
---
 compat/mingw.c         | 4 ++--
 compat/win32/fscache.c | 4 ++--
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/compat/mingw.c b/compat/mingw.c
index 5cc1b58461..3847e0f7a6 100644
--- a/compat/mingw.c
+++ b/compat/mingw.c
@@ -629,8 +629,8 @@ int mingw_lstat(const char *file_name, struct stat *buf)
 		buf->st_nlink = 1;
 		buf->st_mode = file_attr_to_st_mode(fdata.dwFileAttributes,
 				findbuf.dwReserved0);
-		buf->st_size = fdata.nFileSizeLow |
-			(((off_t)fdata.nFileSizeHigh)<<32);
+		buf->st_size = S_ISLNK(buf->st_mode) ? MAX_LONG_PATH :
+			fdata.nFileSizeLow | (((off_t) fdata.nFileSizeHigh) << 32);
 		buf->st_dev = buf->st_rdev = 0; /* not used by Git */
 		buf->st_atime = filetime_to_time_t(&(fdata.ftLastAccessTime));
 		buf->st_mtime = filetime_to_time_t(&(fdata.ftLastWriteTime));
diff --git a/compat/win32/fscache.c b/compat/win32/fscache.c
index f028aae88d..393823389c 100644
--- a/compat/win32/fscache.c
+++ b/compat/win32/fscache.c
@@ -151,8 +151,8 @@ static struct fsentry *fseentry_create_entry(struct fsentry *list,
 
 	fse->st_mode = file_attr_to_st_mode(fdata->dwFileAttributes,
 			fdata->dwReserved0);
-	fse->st_size = (((off64_t) (fdata->nFileSizeHigh)) << 32)
-			| fdata->nFileSizeLow;
+	fse->st_size = S_ISLNK(fse->st_mode) ? MAX_LONG_PATH :
+			fdata->nFileSizeLow | (((off_t) fdata->nFileSizeHigh) << 32);
 	fse->st_atime = filetime_to_time_t(&(fdata->ftLastAccessTime));
 	fse->st_mtime = filetime_to_time_t(&(fdata->ftLastWriteTime));
 	fse->st_ctime = filetime_to_time_t(&(fdata->ftCreationTime));

From e019b6462049f9944d98b5471a43cf1968331876 Mon Sep 17 00:00:00 2001
From: Karsten Blees <blees@dcon.de>
Date: Tue, 19 May 2015 21:48:55 +0200
Subject: [PATCH 15/25] Win32: factor out retry logic

The retry pattern is duplicated in three places. It also seems to be too
hard to use: mingw_unlink() and mingw_rmdir() duplicate the code to retry,
and both of them do so incompletely. They also do not restore errno if the
user answers 'no'.

Introduce a retry_ask_yes_no() helper function that handles retry with
small delay, asking the user, and restoring errno.

mingw_unlink: include _wchmod in the retry loop (which may fail if the
file is locked exclusively).

mingw_rmdir: include special error handling in the retry loop.

Signed-off-by: Karsten Blees <blees@dcon.de>
---
 compat/mingw.c | 98 ++++++++++++++++++++++----------------------------
 1 file changed, 43 insertions(+), 55 deletions(-)

diff --git a/compat/mingw.c b/compat/mingw.c
index 3847e0f7a6..bdf1c70544 100644
--- a/compat/mingw.c
+++ b/compat/mingw.c
@@ -9,8 +9,6 @@
 
 #define HCAST(type, handle) ((type)(intptr_t)handle)
 
-static const int delay[] = { 0, 1, 10, 20, 40 };
-
 int err_win_to_posix(DWORD winerr)
 {
 	int error = ENOSYS;
@@ -173,15 +171,12 @@ static int read_yes_no_answer(void)
 	return -1;
 }
 
-static int ask_yes_no_if_possible(const char *format, ...)
+static int ask_yes_no_if_possible(const char *format, va_list args)
 {
 	char question[4096];
 	const char *retry_hook[] = { NULL, NULL, NULL };
-	va_list args;
 
-	va_start(args, format);
 	vsnprintf(question, sizeof(question), format, args);
-	va_end(args);
 
 	if ((retry_hook[0] = mingw_getenv("GIT_ASK_YESNO"))) {
 		retry_hook[1] = question;
@@ -203,6 +198,31 @@ static int ask_yes_no_if_possible(const char *format, ...)
 	}
 }
 
+static int retry_ask_yes_no(int *tries, const char *format, ...)
+{
+	static const int delay[] = { 0, 1, 10, 20, 40 };
+	va_list args;
+	int result, saved_errno = errno;
+
+	if ((*tries) < ARRAY_SIZE(delay)) {
+		/*
+		 * We assume that some other process had the file open at the wrong
+		 * moment and retry. In order to give the other process a higher
+		 * chance to complete its operation, we give up our time slice now.
+		 * If we have to retry again, we do sleep a bit.
+		 */
+		Sleep(delay[*tries]);
+		(*tries)++;
+		return 1;
+	}
+
+	va_start(args, format);
+	result = ask_yes_no_if_possible(format, args);
+	va_end(args);
+	errno = saved_errno;
+	return result;
+}
+
 /* Windows only */
 enum hide_dotfiles_type {
 	HIDE_DOTFILES_FALSE = 0,
@@ -246,31 +266,21 @@ int mingw_core_config(const char *var, const char *value, void *cb)
 
 int mingw_unlink(const char *pathname)
 {
-	int ret, tries = 0;
+	int tries = 0;
 	wchar_t wpathname[MAX_LONG_PATH];
 	if (xutftowcs_long_path(wpathname, pathname) < 0)
 		return -1;
 
-	/* read-only files cannot be removed */
-	_wchmod(wpathname, 0666);
-	while ((ret = _wunlink(wpathname)) == -1 && tries < ARRAY_SIZE(delay)) {
+	do {
+		/* read-only files cannot be removed */
+		_wchmod(wpathname, 0666);
+		if (!_wunlink(wpathname))
+			return 0;
 		if (!is_file_in_use_error(GetLastError()))
 			break;
-		/*
-		 * We assume that some other process had the source or
-		 * destination file open at the wrong moment and retry.
-		 * In order to give the other process a higher chance to
-		 * complete its operation, we give up our time slice now.
-		 * If we have to retry again, we do sleep a bit.
-		 */
-		Sleep(delay[tries]);
-		tries++;
-	}
-	while (ret == -1 && is_file_in_use_error(GetLastError()) &&
-	       ask_yes_no_if_possible("Unlink of file '%s' failed. "
-			"Should I try again?", pathname))
-	       ret = _wunlink(wpathname);
-	return ret;
+	} while (retry_ask_yes_no(&tries, "Unlink of file '%s' failed. "
+			"Should I try again?", pathname));
+	return -1;
 }
 
 static int is_dir_empty(const wchar_t *wpath)
@@ -297,12 +307,14 @@ static int is_dir_empty(const wchar_t *wpath)
 
 int mingw_rmdir(const char *pathname)
 {
-	int ret, tries = 0;
+	int tries = 0;
 	wchar_t wpathname[MAX_LONG_PATH];
 	if (xutftowcs_long_path(wpathname, pathname) < 0)
 		return -1;
 
-	while ((ret = _wrmdir(wpathname)) == -1 && tries < ARRAY_SIZE(delay)) {
+	do {
+		if (!_wrmdir(wpathname))
+			return 0;
 		if (!is_file_in_use_error(GetLastError()))
 			errno = err_win_to_posix(GetLastError());
 		if (errno != EACCES)
@@ -311,21 +323,9 @@ int mingw_rmdir(const char *pathname)
 			errno = ENOTEMPTY;
 			break;
 		}
-		/*
-		 * We assume that some other process had the source or
-		 * destination file open at the wrong moment and retry.
-		 * In order to give the other process a higher chance to
-		 * complete its operation, we give up our time slice now.
-		 * If we have to retry again, we do sleep a bit.
-		 */
-		Sleep(delay[tries]);
-		tries++;
-	}
-	while (ret == -1 && errno == EACCES && is_file_in_use_error(GetLastError()) &&
-	       ask_yes_no_if_possible("Deletion of directory '%s' failed. "
-			"Should I try again?", pathname))
-	       ret = _wrmdir(wpathname);
-	return ret;
+	} while (retry_ask_yes_no(&tries, "Deletion of directory '%s' failed. "
+			"Should I try again?", pathname));
+	return -1;
 }
 
 static inline int needs_hiding(const char *path)
@@ -1827,20 +1827,8 @@ repeat:
 			SetFileAttributesW(wpnew, attrs);
 		}
 	}
-	if (tries < ARRAY_SIZE(delay) && gle == ERROR_ACCESS_DENIED) {
-		/*
-		 * We assume that some other process had the source or
-		 * destination file open at the wrong moment and retry.
-		 * In order to give the other process a higher chance to
-		 * complete its operation, we give up our time slice now.
-		 * If we have to retry again, we do sleep a bit.
-		 */
-		Sleep(delay[tries]);
-		tries++;
-		goto repeat;
-	}
 	if (gle == ERROR_ACCESS_DENIED &&
-	       ask_yes_no_if_possible("Rename from '%s' to '%s' failed. "
+	       retry_ask_yes_no(&tries, "Rename from '%s' to '%s' failed. "
 		       "Should I try again?", pold, pnew))
 		goto repeat;
 

From 6679af25221142cffc48c1a4e94651abb4978cb1 Mon Sep 17 00:00:00 2001
From: Karsten Blees <blees@dcon.de>
Date: Sun, 24 May 2015 01:55:05 +0200
Subject: [PATCH 16/25] Win32: change default of 'core.symlinks' to false

Symlinks on Windows don't work the same way as on Unix systems. E.g. there
are different types of symlinks for directories and files, creating
symlinks requires administrative privileges etc.

By default, disable symlink support on Windows. I.e. users explicitly have
to enable it with 'git config [--system|--global] core.symlinks true'.

The test suite ignores system / global config files. Allow testing *with*
symlink support by checking if native symlinks are enabled in MSys2 (via
'MSYS=winsymlinks:nativestrict').

Reminder: This would need to be changed if / when we find a way to run the
test suite in a non-MSys-based shell (e.g. dash).

Signed-off-by: Karsten Blees <blees@dcon.de>
---
 compat/mingw.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/compat/mingw.c b/compat/mingw.c
index bdf1c70544..f577376a78 100644
--- a/compat/mingw.c
+++ b/compat/mingw.c
@@ -2295,6 +2295,15 @@ static void setup_windows_environment(void)
 		if (!tmp && (tmp = getenv("USERPROFILE")))
 			setenv("HOME", tmp, 1);
 	}
+
+	/*
+	 * Change 'core.symlinks' default to false, unless native symlinks are
+	 * enabled in MSys2 (via 'MSYS=winsymlinks:nativestrict'). Thus we can
+	 * run the test suite (which doesn't obey config files) with or without
+	 * symlink support.
+	 */
+	if (!(tmp = getenv("MSYS")) || !strstr(tmp, "winsymlinks:nativestrict"))
+		has_symlinks = 0;
 }
 
 int handle_long_path(wchar_t *path, int len, int max_path, int expand)

From f315dd0283f0b38250ff0388aaba455f586488d1 Mon Sep 17 00:00:00 2001
From: Karsten Blees <blees@dcon.de>
Date: Sat, 16 May 2015 00:32:03 +0200
Subject: [PATCH 17/25] Win32: add symlink-specific error codes

Signed-off-by: Karsten Blees <blees@dcon.de>
---
 compat/mingw.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/compat/mingw.c b/compat/mingw.c
index f577376a78..a6f90a8f68 100644
--- a/compat/mingw.c
+++ b/compat/mingw.c
@@ -71,6 +71,7 @@ int err_win_to_posix(DWORD winerr)
 	case ERROR_INVALID_PARAMETER: error = EINVAL; break;
 	case ERROR_INVALID_PASSWORD: error = EPERM; break;
 	case ERROR_INVALID_PRIMARY_GROUP: error = EINVAL; break;
+	case ERROR_INVALID_REPARSE_DATA: error = EINVAL; break;
 	case ERROR_INVALID_SIGNAL_NUMBER: error = EINVAL; break;
 	case ERROR_INVALID_TARGET_HANDLE: error = EIO; break;
 	case ERROR_INVALID_WORKSTATION: error = EACCES; break;
@@ -85,6 +86,7 @@ int err_win_to_posix(DWORD winerr)
 	case ERROR_NEGATIVE_SEEK: error = ESPIPE; break;
 	case ERROR_NOACCESS: error = EFAULT; break;
 	case ERROR_NONE_MAPPED: error = EINVAL; break;
+	case ERROR_NOT_A_REPARSE_POINT: error = EINVAL; break;
 	case ERROR_NOT_ENOUGH_MEMORY: error = ENOMEM; break;
 	case ERROR_NOT_READY: error = EAGAIN; break;
 	case ERROR_NOT_SAME_DEVICE: error = EXDEV; break;
@@ -105,6 +107,9 @@ int err_win_to_posix(DWORD winerr)
 	case ERROR_PIPE_NOT_CONNECTED: error = EPIPE; break;
 	case ERROR_PRIVILEGE_NOT_HELD: error = EACCES; break;
 	case ERROR_READ_FAULT: error = EIO; break;
+	case ERROR_REPARSE_ATTRIBUTE_CONFLICT: error = EINVAL; break;
+	case ERROR_REPARSE_TAG_INVALID: error = EINVAL; break;
+	case ERROR_REPARSE_TAG_MISMATCH: error = EINVAL; break;
 	case ERROR_SEEK: error = EIO; break;
 	case ERROR_SEEK_ON_DEVICE: error = ESPIPE; break;
 	case ERROR_SHARING_BUFFER_EXCEEDED: error = ENFILE; break;

From a77972e8bc4de4621c8df12932fc812e6ecbd97a Mon Sep 17 00:00:00 2001
From: Karsten Blees <blees@dcon.de>
Date: Sun, 24 May 2015 01:06:10 +0200
Subject: [PATCH 18/25] Win32: mingw_unlink: support symlinks to directories

_wunlink() / DeleteFileW() refuses to delete symlinks to directories. If
_wunlink() fails with ERROR_ACCESS_DENIED, try _wrmdir() as well.

Signed-off-by: Karsten Blees <blees@dcon.de>
---
 compat/mingw.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/compat/mingw.c b/compat/mingw.c
index a6f90a8f68..ac829e6152 100644
--- a/compat/mingw.c
+++ b/compat/mingw.c
@@ -283,6 +283,13 @@ int mingw_unlink(const char *pathname)
 			return 0;
 		if (!is_file_in_use_error(GetLastError()))
 			break;
+		/*
+		 * _wunlink() / DeleteFileW() for directory symlinks fails with
+		 * ERROR_ACCESS_DENIED (EACCES), so try _wrmdir() as well. This is the
+		 * same error we get if a file is in use (already checked above).
+		 */
+		if (!_wrmdir(wpathname))
+			return 0;
 	} while (retry_ask_yes_no(&tries, "Unlink of file '%s' failed. "
 			"Should I try again?", pathname));
 	return -1;

From f8d8632d11141648f5447ea2b902e65a61634962 Mon Sep 17 00:00:00 2001
From: Karsten Blees <blees@dcon.de>
Date: Tue, 19 May 2015 22:42:48 +0200
Subject: [PATCH 19/25] Win32: mingw_rename: support renaming symlinks

MSVCRT's _wrename() cannot rename symlinks over existing files: it returns
success without doing anything. Newer MSVCR*.dll versions probably do not
have this problem: according to CRT sources, they just call MoveFileEx()
with the MOVEFILE_COPY_ALLOWED flag.

Get rid of _wrename() and call MoveFileEx() with proper error handling.

Signed-off-by: Karsten Blees <blees@dcon.de>
---
 compat/mingw.c | 39 +++++++++++++++++----------------------
 1 file changed, 17 insertions(+), 22 deletions(-)

diff --git a/compat/mingw.c b/compat/mingw.c
index ac829e6152..6d8f2e1b7a 100644
--- a/compat/mingw.c
+++ b/compat/mingw.c
@@ -1799,28 +1799,29 @@ int mingw_accept(int sockfd1, struct sockaddr *sa, socklen_t *sz)
 #undef rename
 int mingw_rename(const char *pold, const char *pnew)
 {
-	DWORD attrs, gle;
+	DWORD attrs = INVALID_FILE_ATTRIBUTES, gle;
 	int tries = 0;
 	wchar_t wpold[MAX_LONG_PATH], wpnew[MAX_LONG_PATH];
 	if (xutftowcs_long_path(wpold, pold) < 0 ||
 	    xutftowcs_long_path(wpnew, pnew) < 0)
 		return -1;
 
-	/*
-	 * Try native rename() first to get errno right.
-	 * It is based on MoveFile(), which cannot overwrite existing files.
-	 */
-	if (!_wrename(wpold, wpnew))
-		return 0;
-	if (errno != EEXIST)
-		return -1;
 repeat:
-	if (MoveFileExW(wpold, wpnew, MOVEFILE_REPLACE_EXISTING))
+	if (MoveFileExW(wpold, wpnew,
+			MOVEFILE_REPLACE_EXISTING | MOVEFILE_COPY_ALLOWED))
 		return 0;
-	/* TODO: translate more errors */
 	gle = GetLastError();
-	if (gle == ERROR_ACCESS_DENIED &&
-	    (attrs = GetFileAttributesW(wpnew)) != INVALID_FILE_ATTRIBUTES) {
+
+	/* revert file attributes on failure */
+	if (attrs != INVALID_FILE_ATTRIBUTES)
+		SetFileAttributesW(wpnew, attrs);
+
+	if (!is_file_in_use_error(gle)) {
+		errno = err_win_to_posix(gle);
+		return -1;
+	}
+
+	if ((attrs = GetFileAttributesW(wpnew)) != INVALID_FILE_ATTRIBUTES) {
 		if (attrs & FILE_ATTRIBUTE_DIRECTORY) {
 			DWORD attrsold = GetFileAttributesW(wpold);
 			if (attrsold == INVALID_FILE_ATTRIBUTES ||
@@ -1831,16 +1832,10 @@ repeat:
 			return -1;
 		}
 		if ((attrs & FILE_ATTRIBUTE_READONLY) &&
-		    SetFileAttributesW(wpnew, attrs & ~FILE_ATTRIBUTE_READONLY)) {
-			if (MoveFileExW(wpold, wpnew, MOVEFILE_REPLACE_EXISTING))
-				return 0;
-			gle = GetLastError();
-			/* revert file attributes on failure */
-			SetFileAttributesW(wpnew, attrs);
-		}
+		    SetFileAttributesW(wpnew, attrs & ~FILE_ATTRIBUTE_READONLY))
+			goto repeat;
 	}
-	if (gle == ERROR_ACCESS_DENIED &&
-	       retry_ask_yes_no(&tries, "Rename from '%s' to '%s' failed. "
+	if (retry_ask_yes_no(&tries, "Rename from '%s' to '%s' failed. "
 		       "Should I try again?", pold, pnew))
 		goto repeat;
 

From 44c8004594bb81b7dadca41acea8bead1c2bfb90 Mon Sep 17 00:00:00 2001
From: Karsten Blees <blees@dcon.de>
Date: Sun, 24 May 2015 01:17:31 +0200
Subject: [PATCH 20/25] Win32: mingw_chdir: change to symlink-resolved
 directory

If symlinks are enabled, resolve all symlinks when changing directories,
as required by POSIX.

Note: Git's real_path() function bases its link resolution algorithm on
this property of chdir(). Unfortunately, the current directory on Windows
is limited to only MAX_PATH (260) characters. Therefore using symlinks and
long paths in combination may be problematic.

Note: GetFinalPathNameByHandleW() was introduced with symlink support in
Windows Vista. Thus, for compatibility with Windows XP, we need to load it
dynamically and behave gracefully if it isnt's available.

Signed-off-by: Karsten Blees <blees@dcon.de>
---
 compat/mingw.c | 49 ++++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 48 insertions(+), 1 deletion(-)

diff --git a/compat/mingw.c b/compat/mingw.c
index 6d8f2e1b7a..e8dba11b2f 100644
--- a/compat/mingw.c
+++ b/compat/mingw.c
@@ -269,6 +269,34 @@ int mingw_core_config(const char *var, const char *value, void *cb)
 	return 0;
 }
 
+/* Normalizes NT paths as returned by some low-level APIs. */
+static wchar_t *normalize_ntpath(wchar_t *wbuf)
+{
+	int i;
+	/* fix absolute path prefixes */
+	if (wbuf[0] == '\\') {
+		/* strip NT namespace prefixes */
+		if (!wcsncmp(wbuf, L"\\??\\", 4) ||
+		    !wcsncmp(wbuf, L"\\\\?\\", 4))
+			wbuf += 4;
+		else if (!wcsnicmp(wbuf, L"\\DosDevices\\", 12))
+			wbuf += 12;
+		/* replace remaining '...UNC\' with '\\' */
+		if (!wcsnicmp(wbuf, L"UNC\\", 4)) {
+			wbuf += 2;
+			*wbuf = '\\';
+		}
+	}
+	/* convert backslashes to slashes */
+	for (i = 0; wbuf[i]; i++)
+		if (wbuf[i] == '\\')
+			wbuf[i] = '/';
+	/* remove potential trailing slashes */
+	while (i && wbuf[i - 1] == '/')
+		wbuf[--i] = 0;
+	return wbuf;
+}
+
 int mingw_unlink(const char *pathname)
 {
 	int tries = 0;
@@ -561,10 +589,29 @@ static int current_directory_len = 0;
 int mingw_chdir(const char *dirname)
 {
 	int result;
+	DECLARE_PROC_ADDR(kernel32.dll, DWORD, GetFinalPathNameByHandleW,
+			  HANDLE, LPWSTR, DWORD, DWORD);
 	wchar_t wdirname[MAX_LONG_PATH];
 	if (xutftowcs_long_path(wdirname, dirname) < 0)
 		return -1;
-	result = _wchdir(wdirname);
+
+	if (has_symlinks && INIT_PROC_ADDR(GetFinalPathNameByHandleW)) {
+		HANDLE hnd = CreateFileW(wdirname, 0,
+				FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE, NULL,
+				OPEN_EXISTING, FILE_FLAG_BACKUP_SEMANTICS, NULL);
+		if (hnd == INVALID_HANDLE_VALUE) {
+			errno = err_win_to_posix(GetLastError());
+			return -1;
+		}
+		if (!GetFinalPathNameByHandleW(hnd, wdirname, ARRAY_SIZE(wdirname), 0)) {
+			errno = err_win_to_posix(GetLastError());
+			CloseHandle(hnd);
+			return -1;
+		}
+		CloseHandle(hnd);
+	}
+
+	result = _wchdir(normalize_ntpath(wdirname));
 	current_directory_len = GetCurrentDirectoryW(0, NULL);
 	return result;
 }

From 0fc0b66d21022574e5e275131aa5d7097d93715e Mon Sep 17 00:00:00 2001
From: Karsten Blees <blees@dcon.de>
Date: Sun, 24 May 2015 01:24:41 +0200
Subject: [PATCH 21/25] Win32: implement readlink()

Implement readlink() by reading NTFS reparse points. Works for symlinks
and directory junctions. If symlinks are disabled, fail with ENOSYS.

Signed-off-by: Karsten Blees <blees@dcon.de>
---
 compat/mingw.c | 101 +++++++++++++++++++++++++++++++++++++++++++++++++
 compat/mingw.h |   3 +-
 2 files changed, 102 insertions(+), 2 deletions(-)

diff --git a/compat/mingw.c b/compat/mingw.c
index e8dba11b2f..42987adb85 100644
--- a/compat/mingw.c
+++ b/compat/mingw.c
@@ -2,6 +2,7 @@
 #include "win32.h"
 #include <conio.h>
 #include <wchar.h>
+#include <winioctl.h>
 #include "../strbuf.h"
 #include "../run-command.h"
 #include "../cache.h"
@@ -2134,6 +2135,106 @@ int link(const char *oldpath, const char *newpath)
 	return 0;
 }
 
+#ifndef _WINNT_H
+/*
+ * The REPARSE_DATA_BUFFER structure is defined in the Windows DDK (in
+ * ntifs.h) and in MSYS1's winnt.h (which defines _WINNT_H). So define
+ * it ourselves if we are on MSYS2 (whose winnt.h defines _WINNT_).
+ */
+typedef struct _REPARSE_DATA_BUFFER {
+	DWORD  ReparseTag;
+	WORD   ReparseDataLength;
+	WORD   Reserved;
+	_ANONYMOUS_UNION union {
+		struct {
+			WORD   SubstituteNameOffset;
+			WORD   SubstituteNameLength;
+			WORD   PrintNameOffset;
+			WORD   PrintNameLength;
+			ULONG  Flags;
+			WCHAR PathBuffer[1];
+		} SymbolicLinkReparseBuffer;
+		struct {
+			WORD   SubstituteNameOffset;
+			WORD   SubstituteNameLength;
+			WORD   PrintNameOffset;
+			WORD   PrintNameLength;
+			WCHAR PathBuffer[1];
+		} MountPointReparseBuffer;
+		struct {
+			BYTE   DataBuffer[1];
+		} GenericReparseBuffer;
+	} DUMMYUNIONNAME;
+} REPARSE_DATA_BUFFER, *PREPARSE_DATA_BUFFER;
+#endif
+
+int readlink(const char *path, char *buf, size_t bufsiz)
+{
+	HANDLE handle;
+	WCHAR wpath[MAX_LONG_PATH], *wbuf;
+	REPARSE_DATA_BUFFER *b = alloca(MAXIMUM_REPARSE_DATA_BUFFER_SIZE);
+	DWORD dummy;
+	char tmpbuf[MAX_LONG_PATH];
+	int len;
+
+	/* fail if symlinks are disabled */
+	if (!has_symlinks) {
+		errno = ENOSYS;
+		return -1;
+	}
+
+	if (xutftowcs_long_path(wpath, path) < 0)
+		return -1;
+
+	/* read reparse point data */
+	handle = CreateFileW(wpath, 0,
+			FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE, NULL,
+			OPEN_EXISTING,
+			FILE_FLAG_BACKUP_SEMANTICS | FILE_FLAG_OPEN_REPARSE_POINT, NULL);
+	if (handle == INVALID_HANDLE_VALUE) {
+		errno = err_win_to_posix(GetLastError());
+		return -1;
+	}
+	if (!DeviceIoControl(handle, FSCTL_GET_REPARSE_POINT, NULL, 0, b,
+			MAXIMUM_REPARSE_DATA_BUFFER_SIZE, &dummy, NULL)) {
+		errno = err_win_to_posix(GetLastError());
+		CloseHandle(handle);
+		return -1;
+	}
+	CloseHandle(handle);
+
+	/* get target path for symlinks or mount points (aka 'junctions') */
+	switch (b->ReparseTag) {
+	case IO_REPARSE_TAG_SYMLINK:
+		wbuf = (WCHAR*) (((char*) b->SymbolicLinkReparseBuffer.PathBuffer)
+				+ b->SymbolicLinkReparseBuffer.SubstituteNameOffset);
+		*(WCHAR*) (((char*) wbuf)
+				+ b->SymbolicLinkReparseBuffer.SubstituteNameLength) = 0;
+		break;
+	case IO_REPARSE_TAG_MOUNT_POINT:
+		wbuf = (WCHAR*) (((char*) b->MountPointReparseBuffer.PathBuffer)
+				+ b->MountPointReparseBuffer.SubstituteNameOffset);
+		*(WCHAR*) (((char*) wbuf)
+				+ b->MountPointReparseBuffer.SubstituteNameLength) = 0;
+		break;
+	default:
+		errno = EINVAL;
+		return -1;
+	}
+
+	/*
+	 * Adapt to strange readlink() API: Copy up to bufsiz *bytes*, potentially
+	 * cutting off a UTF-8 sequence. Insufficient bufsize is *not* a failure
+	 * condition. There is no conversion function that produces invalid UTF-8,
+	 * so convert to a (hopefully large enough) temporary buffer, then memcpy
+	 * the requested number of bytes (including '\0' for robustness).
+	 */
+	if ((len = xwcstoutf(tmpbuf, normalize_ntpath(wbuf), MAX_LONG_PATH)) < 0)
+		return -1;
+	memcpy(buf, tmpbuf, min(bufsiz, len + 1));
+	return min(bufsiz, len);
+}
+
 pid_t waitpid(pid_t pid, int *status, int options)
 {
 	HANDLE h = OpenProcess(SYNCHRONIZE | PROCESS_QUERY_INFORMATION,
diff --git a/compat/mingw.h b/compat/mingw.h
index d8e077cbe2..228121ab83 100644
--- a/compat/mingw.h
+++ b/compat/mingw.h
@@ -123,8 +123,6 @@ struct utsname {
  * trivial stubs
  */
 
-static inline int readlink(const char *path, char *buf, size_t bufsiz)
-{ errno = ENOSYS; return -1; }
 static inline int symlink(const char *oldpath, const char *newpath)
 { errno = ENOSYS; return -1; }
 static inline int fchmod(int fildes, mode_t mode)
@@ -218,6 +216,7 @@ int setitimer(int type, struct itimerval *in, struct itimerval *out);
 int sigaction(int sig, struct sigaction *in, struct sigaction *out);
 int link(const char *oldpath, const char *newpath);
 int uname(struct utsname *buf);
+int readlink(const char *path, char *buf, size_t bufsiz);
 
 /*
  * replacements of existing functions

From ad1464f0f619df485aeb78de7e254e6092c731c0 Mon Sep 17 00:00:00 2001
From: Karsten Blees <blees@dcon.de>
Date: Sun, 24 May 2015 01:32:03 +0200
Subject: [PATCH 22/25] Win32: implement basic symlink() functionality (file
 symlinks only)

Implement symlink() that always creates file symlinks. Fails with ENOSYS
if symlinks are disabled or unsupported.

Note: CreateSymbolicLinkW() was introduced with symlink support in Windows
Vista. For compatibility with Windows XP, we need to load it dynamically
and fail gracefully if it isnt's available.

Signed-off-by: Karsten Blees <blees@dcon.de>
---
 compat/mingw.c | 30 ++++++++++++++++++++++++++++++
 compat/mingw.h |  3 +--
 2 files changed, 31 insertions(+), 2 deletions(-)

diff --git a/compat/mingw.c b/compat/mingw.c
index 42987adb85..90729a96ab 100644
--- a/compat/mingw.c
+++ b/compat/mingw.c
@@ -270,6 +270,8 @@ int mingw_core_config(const char *var, const char *value, void *cb)
 	return 0;
 }
 
+DECLARE_PROC_ADDR(kernel32.dll, BOOLEAN, CreateSymbolicLinkW, LPCWSTR, LPCWSTR, DWORD);
+
 /* Normalizes NT paths as returned by some low-level APIs. */
 static wchar_t *normalize_ntpath(wchar_t *wbuf)
 {
@@ -2135,6 +2137,34 @@ int link(const char *oldpath, const char *newpath)
 	return 0;
 }
 
+int symlink(const char *target, const char *link)
+{
+	wchar_t wtarget[MAX_LONG_PATH], wlink[MAX_LONG_PATH];
+	int len;
+
+	/* fail if symlinks are disabled or API is not supported (WinXP) */
+	if (!has_symlinks || !INIT_PROC_ADDR(CreateSymbolicLinkW)) {
+		errno = ENOSYS;
+		return -1;
+	}
+
+	if ((len = xutftowcs_long_path(wtarget, target)) < 0
+			|| xutftowcs_long_path(wlink, link) < 0)
+		return -1;
+
+	/* convert target dir separators to backslashes */
+	while (len--)
+		if (wtarget[len] == '/')
+			wtarget[len] = '\\';
+
+	/* create file symlink */
+	if (!CreateSymbolicLinkW(wlink, wtarget, 0)) {
+		errno = err_win_to_posix(GetLastError());
+		return -1;
+	}
+	return 0;
+}
+
 #ifndef _WINNT_H
 /*
  * The REPARSE_DATA_BUFFER structure is defined in the Windows DDK (in
diff --git a/compat/mingw.h b/compat/mingw.h
index 228121ab83..5c7fdc1b67 100644
--- a/compat/mingw.h
+++ b/compat/mingw.h
@@ -123,8 +123,6 @@ struct utsname {
  * trivial stubs
  */
 
-static inline int symlink(const char *oldpath, const char *newpath)
-{ errno = ENOSYS; return -1; }
 static inline int fchmod(int fildes, mode_t mode)
 { errno = ENOSYS; return -1; }
 #ifndef __MINGW64_VERSION_MAJOR
@@ -216,6 +214,7 @@ int setitimer(int type, struct itimerval *in, struct itimerval *out);
 int sigaction(int sig, struct sigaction *in, struct sigaction *out);
 int link(const char *oldpath, const char *newpath);
 int uname(struct utsname *buf);
+int symlink(const char *target, const char *link);
 int readlink(const char *path, char *buf, size_t bufsiz);
 
 /*

From 2857bb0942fd388a52a97356f6c0ec08c2a85526 Mon Sep 17 00:00:00 2001
From: Karsten Blees <blees@dcon.de>
Date: Sun, 24 May 2015 01:48:35 +0200
Subject: [PATCH 23/25] Win32: symlink: add support for symlinks to directories

Symlinks on Windows have a flag that indicates whether the target is a file
or a directory. Symlinks of wrong type simply don't work. This even affects
core Win32 APIs (e.g. DeleteFile() refuses to delete directory symlinks).

However, CreateFile() with FILE_FLAG_BACKUP_SEMANTICS doesn't seem to care.
Check the target type by first creating a tentative file symlink, opening
it, and checking the type of the resulting handle. If it is a directory,
recreate the symlink with the directory flag set.

It is possible to create symlinks before the target exists (or in case of
symlinks to symlinks: before the target type is known). If this happens,
create a tentative file symlink and postpone the directory decision: keep
a list of phantom symlinks to be processed whenever a new directory is
created in mingw_mkdir().

Limitations: This algorithm may fail if a link target changes from file to
directory or vice versa, or if the target directory is created in another
process.

Signed-off-by: Karsten Blees <blees@dcon.de>
---
 compat/mingw.c | 164 +++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 164 insertions(+)

diff --git a/compat/mingw.c b/compat/mingw.c
index 90729a96ab..a5131d7042 100644
--- a/compat/mingw.c
+++ b/compat/mingw.c
@@ -272,6 +272,131 @@ int mingw_core_config(const char *var, const char *value, void *cb)
 
 DECLARE_PROC_ADDR(kernel32.dll, BOOLEAN, CreateSymbolicLinkW, LPCWSTR, LPCWSTR, DWORD);
 
+enum phantom_symlink_result {
+	PHANTOM_SYMLINK_RETRY,
+	PHANTOM_SYMLINK_DONE,
+	PHANTOM_SYMLINK_DIRECTORY
+};
+
+static inline int is_wdir_sep(wchar_t wchar)
+{
+	return wchar == L'/' || wchar == L'\\';
+}
+
+static const wchar_t *make_relative_to(const wchar_t *path,
+				       const wchar_t *relative_to, wchar_t *out,
+				       size_t size)
+{
+	size_t i = wcslen(relative_to), len;
+
+	/* Is `path` already absolute? */
+	if (is_wdir_sep(path[0]) ||
+	    (iswalpha(path[0]) && path[1] == L':' && is_wdir_sep(path[2])))
+		return path;
+
+	while (i > 0 && !is_wdir_sep(relative_to[i - 1]))
+		i--;
+
+	/* Is `relative_to` in the current directory? */
+	if (!i)
+		return path;
+
+	len = wcslen(path);
+	if (i + len + 1 > size) {
+		error("Could not make '%S' relative to '%S' (too large)",
+		      path, relative_to);
+		return NULL;
+	}
+
+	memcpy(out, relative_to, i * sizeof(wchar_t));
+	wcscpy(out + i, path);
+	return out;
+}
+
+/*
+ * Changes a file symlink to a directory symlink if the target exists and is a
+ * directory.
+ */
+static enum phantom_symlink_result
+process_phantom_symlink(const wchar_t *wtarget, const wchar_t *wlink)
+{
+	HANDLE hnd;
+	BY_HANDLE_FILE_INFORMATION fdata;
+	wchar_t relative[MAX_LONG_PATH];
+	const wchar_t *rel;
+
+	/* check that wlink is still a file symlink */
+	if ((GetFileAttributesW(wlink)
+			& (FILE_ATTRIBUTE_REPARSE_POINT | FILE_ATTRIBUTE_DIRECTORY))
+			!= FILE_ATTRIBUTE_REPARSE_POINT)
+		return PHANTOM_SYMLINK_DONE;
+
+	/* make it relative, if necessary */
+	rel = make_relative_to(wtarget, wlink, relative, ARRAY_SIZE(relative));
+	if (!rel)
+		return PHANTOM_SYMLINK_DONE;
+
+	/* let Windows resolve the link by opening it */
+	hnd = CreateFileW(rel, 0,
+			FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE, NULL,
+			OPEN_EXISTING, FILE_FLAG_BACKUP_SEMANTICS, NULL);
+	if (hnd == INVALID_HANDLE_VALUE) {
+		errno = err_win_to_posix(GetLastError());
+		return PHANTOM_SYMLINK_RETRY;
+	}
+
+	if (!GetFileInformationByHandle(hnd, &fdata)) {
+		errno = err_win_to_posix(GetLastError());
+		CloseHandle(hnd);
+		return PHANTOM_SYMLINK_RETRY;
+	}
+	CloseHandle(hnd);
+
+	/* if target exists and is a file, we're done */
+	if (!(fdata.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY))
+		return PHANTOM_SYMLINK_DONE;
+
+	/* otherwise recreate the symlink with directory flag */
+	if (DeleteFileW(wlink) && CreateSymbolicLinkW(wlink, wtarget, 1))
+		return PHANTOM_SYMLINK_DIRECTORY;
+
+	errno = err_win_to_posix(GetLastError());
+	return PHANTOM_SYMLINK_RETRY;
+}
+
+/* keep track of newly created symlinks to non-existing targets */
+struct phantom_symlink_info {
+	struct phantom_symlink_info *next;
+	wchar_t *wlink;
+	wchar_t *wtarget;
+};
+
+static struct phantom_symlink_info *phantom_symlinks = NULL;
+static CRITICAL_SECTION phantom_symlinks_cs;
+
+static void process_phantom_symlinks(void)
+{
+	struct phantom_symlink_info *current, **psi;
+	EnterCriticalSection(&phantom_symlinks_cs);
+	/* process phantom symlinks list */
+	psi = &phantom_symlinks;
+	while ((current = *psi)) {
+		enum phantom_symlink_result result = process_phantom_symlink(
+				current->wtarget, current->wlink);
+		if (result == PHANTOM_SYMLINK_RETRY) {
+			psi = &current->next;
+		} else {
+			/* symlink was processed, remove from list */
+			*psi = current->next;
+			free(current);
+			/* if symlink was a directory, start over */
+			if (result == PHANTOM_SYMLINK_DIRECTORY)
+				psi = &phantom_symlinks;
+		}
+	}
+	LeaveCriticalSection(&phantom_symlinks_cs);
+}
+
 /* Normalizes NT paths as returned by some low-level APIs. */
 static wchar_t *normalize_ntpath(wchar_t *wbuf)
 {
@@ -424,6 +549,8 @@ int mingw_mkdir(const char *path, int mode)
 		return -1;
 
 	ret = _wmkdir(wpath);
+	if (!ret)
+		process_phantom_symlinks();
 	if (!ret && needs_hiding(path))
 		return set_hidden_flag(wpath, 1);
 	return ret;
@@ -2162,6 +2289,42 @@ int symlink(const char *target, const char *link)
 		errno = err_win_to_posix(GetLastError());
 		return -1;
 	}
+
+	/* convert to directory symlink if target exists */
+	switch (process_phantom_symlink(wtarget, wlink)) {
+	case PHANTOM_SYMLINK_RETRY:	{
+		/* if target doesn't exist, add to phantom symlinks list */
+		wchar_t wfullpath[MAX_LONG_PATH];
+		struct phantom_symlink_info *psi;
+
+		/* convert to absolute path to be independent of cwd */
+		len = GetFullPathNameW(wlink, MAX_LONG_PATH, wfullpath, NULL);
+		if (!len || len >= MAX_LONG_PATH) {
+			errno = err_win_to_posix(GetLastError());
+			return -1;
+		}
+
+		/* over-allocate and fill phantom_symlink_info structure */
+		psi = xmalloc(sizeof(struct phantom_symlink_info)
+			+ sizeof(wchar_t) * (len + wcslen(wtarget) + 2));
+		psi->wlink = (wchar_t *)(psi + 1);
+		wcscpy(psi->wlink, wfullpath);
+		psi->wtarget = psi->wlink + len + 1;
+		wcscpy(psi->wtarget, wtarget);
+
+		EnterCriticalSection(&phantom_symlinks_cs);
+		psi->next = phantom_symlinks;
+		phantom_symlinks = psi;
+		LeaveCriticalSection(&phantom_symlinks_cs);
+		break;
+	}
+	case PHANTOM_SYMLINK_DIRECTORY:
+		/* if we created a dir symlink, process other phantom symlinks */
+		process_phantom_symlinks();
+		break;
+	default:
+		break;
+	}
 	return 0;
 }
 
@@ -2706,6 +2869,7 @@ void mingw_startup(void)
 
 	/* initialize critical section for waitpid pinfo_t list */
 	InitializeCriticalSection(&pinfo_cs);
+	InitializeCriticalSection(&phantom_symlinks_cs);
 
 	/* set up default file mode and file modes for stdin/out/err */
 	_fmode = _O_BINARY;

From 0e78f5c6aed7b813e896a7102c98e2f4450b6f07 Mon Sep 17 00:00:00 2001
From: Johannes Schindelin <johannes.schindelin@gmx.de>
Date: Fri, 19 Jun 2015 21:00:46 +0000
Subject: [PATCH 24/25] mingw: keep trailing slashes for _wchdir() and
 readlink()

This is needed so that `_wchdir()` can be used with drive root
directories, e.g. C:\ (`_wchdir("C:")` fails to switch the directory
to the root directory).

This fixes https://github.com/msysgit/git/issues/359 (in Git for Windows
2.x only, though).

Likewise, `readlink()`'s semantics require a trailing slash for symbolic
links pointing to directories. Otherwise all checked out symbolic links
pointing to directories would be marked as modified even directly after a
fresh clone.

This fixes https://github.com/git-for-windows/git/issues/210

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
---
 compat/mingw.c | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/compat/mingw.c b/compat/mingw.c
index a5131d7042..4de34f06ad 100644
--- a/compat/mingw.c
+++ b/compat/mingw.c
@@ -419,9 +419,6 @@ static wchar_t *normalize_ntpath(wchar_t *wbuf)
 	for (i = 0; wbuf[i]; i++)
 		if (wbuf[i] == '\\')
 			wbuf[i] = '/';
-	/* remove potential trailing slashes */
-	while (i && wbuf[i - 1] == '/')
-		wbuf[--i] = 0;
 	return wbuf;
 }
 

From 8c74ac4e7441e835c88af5359d519651198207f0 Mon Sep 17 00:00:00 2001
From: lchiocca <loris@chiocca.ch>
Date: Mon, 22 Jun 2015 10:29:43 +0200
Subject: [PATCH 25/25] The stat() function should be independent of
 core.symlinks

The contract for the stat() and lstat() function is:
> stat():  stats the file pointed to by path and fills in buf.
> lstat(): is identical to stat(), except that if path is a symbolic link,
>          then the link itself is stat-ed, not the file that it refers to.

stat() should always return the statistics of the file or directory a
symbolic link is pointing to. The lstat() function is used to get the
stats for the symlink. Hence the check should not be there.

Signed-off-by: Loris Chiocca <loris@chiocca.ch>
---
 compat/mingw.c | 12 +-----------
 1 file changed, 1 insertion(+), 11 deletions(-)

diff --git a/compat/mingw.c b/compat/mingw.c
index 4de34f06ad..fb7a69ca36 100644
--- a/compat/mingw.c
+++ b/compat/mingw.c
@@ -877,17 +877,7 @@ int mingw_stat(const char *file_name, struct stat *buf)
 	HANDLE hnd;
 	int result;
 
-	/* if symlinks are disabled, use lstat() (without following links) */
-	if (!has_symlinks) {
-		result = lstat(file_name, buf);
-		if (!result && S_ISLNK(buf->st_mode)) {
-			errno = ELOOP;
-			return -1;
-		}
-		return result;
-	}
-
-	/* otherwise just open the file and let Windows resolve the links */
+	/* open the file and let Windows resolve the links */
 	if (xutftowcs_long_path(wfile_name, file_name) < 0)
 		return -1;
 	hnd = CreateFileW(wfile_name, 0,