diff --git a/include/misc.h b/include/misc.h
index e805cf68..68b7ebee 100644
--- a/include/misc.h
+++ b/include/misc.h
@@ -59,9 +59,24 @@ typedef int pid_t;
 #define mkdir(dir,perm) _mkdir((dir))
 #define random rand
 #define srandom srand
-
+#define S_IRUSR	    _S_IREAD
+#define S_IWUSR	    _S_IWRITE
+#define S_IXUSR	    _S_IREAD
+#define S_IRGRP	    _S_IREAD
+#define S_IWGRP	    _S_IWRITE
+#define S_IXGRP	    _S_IREAD
+#define S_IROTH	    _S_IREAD
+#define S_IWOTH	    _S_IWRITE
+#define S_IXOTH	    _S_IREAD
+#define S_IRWXU	    S_IRUSR | S_IWUSR | S_IXUSR
+#define S_IRWXG	    S_IRGRP | S_IWGRP | S_IXGRP
+#define S_IRWXO	    S_IROTH | S_IWOTH | S_IXOTH
 #endif /* _WIN32 */
 
+#ifndef S_IRWUG
+#define S_IRWUG	    S_IRGRP | S_IWGRP | S_IRUSR | S_IWUSR
+#endif
+
 /* This is the structure we use to keep track of the global mobility
    things, such as when the server is supposed to start/stop updating
    mobility and the timestamp of when the game was last up.  These
diff --git a/src/lib/commands/add.c b/src/lib/commands/add.c
index efd99ecb..16e2b77d 100644
--- a/src/lib/commands/add.c
+++ b/src/lib/commands/add.c
@@ -37,6 +37,7 @@
 #if defined(_WIN32)
 #include <io.h>
 #endif
+#include <sys/stat.h>
 
 #include "commands.h"
 #include "land.h"
@@ -213,7 +214,7 @@ add(void)
 	    natp->nat_rejects[i] = 0;
 	natp->nat_newstim = 0;
 	natp->nat_annotim = 0;
-	(void)creat(mailbox(buf, coun), 0660);
+	(void)creat(mailbox(buf, coun), S_IRWUG);
     } else
 	pr("No special initializations done...\n");
 
diff --git a/src/lib/commands/disa.c b/src/lib/commands/disa.c
index 2aa9184b..ca2534d5 100644
--- a/src/lib/commands/disa.c
+++ b/src/lib/commands/disa.c
@@ -37,6 +37,7 @@
 #include <io.h>
 #endif
 #include <fcntl.h>
+#include <sys/stat.h>
 #if !defined(_WIN32)
 #include <unistd.h>
 #endif
@@ -48,7 +49,7 @@ disa(void)
 {
     int fd;
 
-    if ((fd = open(disablefil, O_RDWR | O_CREAT | O_TRUNC, 0660)) < 0)
+    if ((fd = open(disablefil, O_RDWR | O_CREAT | O_TRUNC, S_IRWUG)) < 0)
 	return RET_FAIL;
     close(fd);
     pr("Updates are disabled\n");
diff --git a/src/lib/common/file.c b/src/lib/common/file.c
index f43dda0b..2ed507b0 100644
--- a/src/lib/common/file.c
+++ b/src/lib/common/file.c
@@ -41,6 +41,7 @@
 #include <share.h>
 #endif
 #include <fcntl.h>
+#include <sys/stat.h>
 #include <signal.h>
 #include <sys/types.h>
 #if !defined(_WIN32)
@@ -90,12 +91,12 @@ ef_open(int type, int how)
     oflags |= O_BINARY;
     if ((fd = sopen(ep->file, oflags,
 	how & EFF_RDONLY ? SH_DENYNO : SH_DENYWR,
-	0660)) < 0) {
+	S_IRWUG)) < 0) {
 	logerror("Can't open %s (%s)", ep->file, strerror(errno));
 	return 0;
     }
 #else
-    if ((fd = open(ep->file, oflags, 0660)) < 0) {
+    if ((fd = open(ep->file, oflags, S_IRWUG)) < 0) {
 	logerror("Can't open %s (%s)", ep->file, strerror(errno));
 	return 0;
     }
diff --git a/src/lib/common/log.c b/src/lib/common/log.c
index b7eda713..52869112 100644
--- a/src/lib/common/log.c
+++ b/src/lib/common/log.c
@@ -40,6 +40,7 @@
 #include <unistd.h>
 #endif
 #include <fcntl.h>
+#include <sys/stat.h>
 #include <stdarg.h>
 #include <stdio.h>
 #include <time.h>
@@ -93,7 +94,8 @@ logerror(char *format, ...)
 	time(&now);
 	memcpy(buf, ctime(&now), ctime_len);
 	buf[ctime_len] = ' ';
-	if ((logf = open(logfile, O_WRONLY | O_CREAT | O_APPEND, 0660)) < 0)
+	if ((logf = open(logfile, O_WRONLY | O_CREAT | O_APPEND,
+			 S_IRWUG)) < 0)
 	    return;
 	write(logf, buf, strlen(buf));
 	close(logf);
diff --git a/src/util/files.c b/src/util/files.c
index c4436977..9da0132b 100644
--- a/src/util/files.c
+++ b/src/util/files.c
@@ -36,13 +36,13 @@
 #include <config.h>
 
 #include <fcntl.h>
+#include <sys/stat.h>
 #include <errno.h>
 #if defined(_WIN32)
 #include <direct.h>
 #include <io.h>
 #include "../lib/gen/getopt.h"
 #else
-#include <sys/stat.h>
 #include <unistd.h>
 #endif
 
@@ -117,7 +117,7 @@ main(int argc, char *argv[])
 
     ef_init();
 
-    if (mkdir(gamedir, 0770) < 0 && errno != EEXIST) {
+    if (mkdir(gamedir, S_IRWXU | S_IRWXG) < 0 && errno != EEXIST) {
 	perror(gamedir);
 	printf("Can't make game directory\n");
 	exit(1);
@@ -171,17 +171,17 @@ main(int argc, char *argv[])
 	    putrealm(&realm);
 	}
     }
-    if (mkdir(teldir, 0770) < 0 && errno != EEXIST) {
+    if (mkdir(teldir, S_IRWXU | S_IRWXG) < 0 && errno != EEXIST) {
 	perror(teldir);
 	printf("Can't make telegram directory\n");
 	exit(1);
     }
     for (x = MAXNOC - 1; x >= 0; x--) {
 	filename = mailbox(buf, x);
-	close(creat(filename, 0660));
+	close(creat(filename, S_IRWUG));
     }
-    close(creat(timestampfil, 0660));
-    close(creat(annfil, 0660));
+    close(creat(timestampfil, S_IRWUG));
+    close(creat(annfil, S_IRWUG));
 
     /* create a zero-filled sector file */
     memset(&sct, 0, sizeof(sct));