diff --git a/usr.bin/at/panic.c b/usr.bin/at/panic.c
index 9cabc1da0d5e..cf6d041e3daf 100644
--- a/usr.bin/at/panic.c
+++ b/usr.bin/at/panic.c
@@ -39,6 +39,7 @@ static const char rcsid[] =
 /* Local headers */
 
 #include "panic.h"
+#include "privs.h"
 #include "at.h"
 
 /* External variables */
@@ -50,8 +51,11 @@ panic(char *a)
 {
 /* Something fatal has happened, print error message and exit.
  */
-	if (fcreated)
+	if (fcreated) {
+		PRIV_START
 		unlink(atfile);
+		PRIV_END
+	}
 
 	errx(EXIT_FAILURE, "%s", a);
 }
@@ -63,8 +67,11 @@ perr(char *a)
  */
 	int serrno = errno;
 
-	if (fcreated)
+	if (fcreated) {
+		PRIV_START
 		unlink(atfile);
+		PRIV_END
+	}
 
 	errno = serrno;
 	err(EXIT_FAILURE, "%s", a);
diff --git a/usr.bin/at/privs.h b/usr.bin/at/privs.h
index 2fce5c02e4a6..50dd6b108af4 100644
--- a/usr.bin/at/privs.h
+++ b/usr.bin/at/privs.h
@@ -28,17 +28,11 @@
 #ifndef _PRIVS_H
 #define _PRIVS_H
 
-#ifndef _USE_BSD
-#define _USE_BSD 1
 #include <unistd.h>
-#undef _USE_BSD
-#else
-#include <unistd.h>
-#endif
 
 /* Relinquish privileges temporarily for a setuid or setgid program
- * with the option of getting them back later.  This is done by swapping
- * the real and effective userid BSD style.  Call RELINQUISH_PRIVS once
+ * with the option of getting them back later.  This is done by
+ * utilizing POSIX saved user and group IDs.  Call RELINQUISH_PRIVS once
  * at the beginning of the main program.  This will cause all operations
  * to be executed with the real userid.  When you need the privileges
  * of the setuid/setgid invocation, call PRIV_START; when you no longer
@@ -76,38 +70,39 @@ extern
 gid_t real_gid, effective_gid;
 
 #define RELINQUISH_PRIVS { \
-			      real_uid = getuid(); \
-			      effective_uid = geteuid(); \
-			      real_gid = getgid(); \
-			      effective_gid = getegid(); \
-			      setreuid(effective_uid, real_uid); \
-			      setregid(effective_gid, real_gid); \
-		          }
+	real_uid = getuid(); \
+	effective_uid = geteuid(); \
+	real_gid = getgid(); \
+	effective_gid = getegid(); \
+	seteuid(real_uid); \
+	setegid(real_gid); \
+}
 
-#define RELINQUISH_PRIVS_ROOT(a,b) { \
-			      real_uid = (a); \
-			      effective_uid = geteuid(); \
-			      real_gid = (b); \
-			      effective_gid = getegid(); \
-			      setregid(effective_gid, real_gid); \
-			      setreuid(effective_uid, real_uid); \
-		          }
+#define RELINQUISH_PRIVS_ROOT(a, b) { \
+	real_uid = (a); \
+	effective_uid = geteuid(); \
+	real_gid = (b); \
+	effective_gid = getegid(); \
+	setegid(real_gid); \
+	seteuid(real_uid); \
+}
 
-#define PRIV_START {\
-		    setreuid(real_uid, effective_uid); \
-		    setregid(real_gid, effective_gid);
+#define PRIV_START { \
+	seteuid(effective_uid); \
+	setegid(effective_gid); \
+}
 
-#define PRIV_END \
-		    setregid(effective_gid, real_gid); \
-		    setreuid(effective_uid, real_uid); \
-		    }
+#define PRIV_END { \
+	setegid(real_gid); \
+	seteuid(real_uid); \
+}
 
-#define REDUCE_PRIV(a,b) {\
-			setreuid(real_uid, effective_uid); \
-			setregid(real_gid, effective_gid); \
-			effective_uid = (a); \
-			effective_gid = (b); \
-			setregid(effective_gid, real_gid); \
-			setreuid(effective_uid, real_uid); \
-		    }
+#define REDUCE_PRIV(a, b) { \
+	PRIV_START \
+	effective_uid = (a); \
+	effective_gid = (b); \
+	setreuid((uid_t)-1, effective_uid); \
+	setregid((gid_t)-1, effective_gid); \
+	PRIV_END \
+}
 #endif