Added link() Support

- Added link() support using the CreateHardLink() function.
- Made readlink() and link() declarations consistent with other functions.

contrib/win32/win32compat/fileio.c

@@ -1204,3 +1204,36 @@ cleanup:
 		free(resolved_utf16);
 	return ret;
 }
+
+int 
+fileio_link(const char *oldpath, const char *newpath)
+{
+	if (oldpath == NULL || newpath == NULL) {
+		errno = EFAULT;
+		return -1;
+	}
+
+	DWORD ret = 0;
+	wchar_t *oldpath_utf16 = utf8_to_utf16(resolved_path(oldpath));
+	wchar_t *newpath_utf16 = utf8_to_utf16(resolved_path(newpath));
+	if (oldpath_utf16 == NULL || newpath_utf16 == NULL) {
+		errno = ENOMEM;
+		ret = -1;
+		goto cleanup;
+	}
+
+	if (CreateHardLinkW(newpath_utf16, oldpath_utf16, NULL) == 0) {
+		errno = errno_from_Win32LastError();
+		ret = -1;
+		goto cleanup;
+	}
+
+cleanup:
+
+	if (oldpath_utf16)
+		free(oldpath_utf16);
+	if (newpath_utf16)
+		free(newpath_utf16);
+
+	return ret;
+}

contrib/win32/win32compat/inc/unistd.h

@@ -76,11 +76,14 @@ int w32_chdir(const char *dirname);
 char *w32_getcwd(char *buffer, int maxlen);
 #define getcwd w32_getcwd
 
+int w32_readlink(const char *path, char *link, int linklen);
+#define readlink w32_readlink
+
+int w32_link(const char *oldpath, const char *newpath);
+#define link w32_link
+
 int daemon(int nochdir, int noclose);
 char *crypt(const char *key, const char *salt);
-int link(const char *oldpath, const char *newpath);
-int readlink(const char *path, char *link, int linklen);
-
 int chroot(const char *path);
 
 /* 

contrib/win32/win32compat/misc.c

@@ -661,11 +661,9 @@ w32_symlink(const char *target, const char *linkpath)
 }
 
 int
-link(const char *oldpath, const char *newpath)
+w32_link(const char *oldpath, const char *newpath)
 {
-	/* Not supported in windows */
+	return fileio_link(oldpath, newpath);
-	errno = EOPNOTSUPP;
-	return -1;
 }
 
 int
@@ -831,7 +829,7 @@ w32_lstat(const char *input_path, struct w32_stat *buf)
 
 /* if file is symbolic link, copy its link into "link" */
 int
-readlink(const char *path, char *link, int linklen)
+w32_readlink(const char *path, char *link, int linklen)
 {
 	return fileio_readlink(resolved_path(path), link, linklen);
 }

contrib/win32/win32compat/w32fd.h

@@ -165,4 +165,5 @@ int fileio_lstat(const char *path, struct _stat64 *buf);
 long fileio_lseek(struct w32_io* pio, unsigned __int64 offset, int origin);
 FILE* fileio_fdopen(struct w32_io* pio, const char *mode);
 ssize_t fileio_readlink(const char *path, char *buf, size_t bufsiz);
-int fileio_symlink(const char *target, const char *linkpath);
+int fileio_symlink(const char *target, const char *linkpath);
+int fileio_link(const char *oldpath, const char *newpath);