Use the lckpwdf() again if prefix is not set

The implementation of prefix option dropped the use of lckpwdf().
However that is incorrect as other tools manipulating the shadow passwords
such as PAM use lckpwdf() and do not know anything about the
shadow's own locking mechanism.

This reverts the implementation to use lckpwdf() if prefix option
is not used.

lib/commonio.c

@@ -364,6 +364,7 @@ static void free_linked_list (struct commonio_db *db)
 int commonio_setname (struct commonio_db *db, const char *name)
 {
 	snprintf (db->filename, sizeof (db->filename), "%s", name);
+	db->setname = true;
 	return 1;
 }
 
@@ -414,38 +415,40 @@ cleanup_ENOMEM:
 
 int commonio_lock (struct commonio_db *db)
 {
-/*#ifdef HAVE_LCKPWDF*/ /* not compatible with prefix option*/
-#if 0
-	/*
-	 * only if the system libc has a real lckpwdf() - the one from
-	 * lockpw.c calls us and would cause infinite recursion!
-	 */
-
-	/*
-	 * Call lckpwdf() on the first lock.
-	 * If it succeeds, call *_lock() only once
-	 * (no retries, it should always succeed).
-	 */
-	if (0 == lock_count) {
-		if (lckpwdf () == -1) {
-			if (geteuid () != 0) {
-				(void) fprintf (stderr,
-				                "%s: Permission denied.\n",
-				                Prog);
-			}
-			return 0;	/* failure */
-		}
-	}
-
-	if (commonio_lock_nowait (db, true) != 0) {
-		return 1;	/* success */
-	}
-
-	ulckpwdf ();
-	return 0;		/* failure */
-#else				/* !HAVE_LCKPWDF */
 	int i;
 
+#ifdef HAVE_LCKPWDF
+	/*
+	 * Only if the system libc has a real lckpwdf() - the one from
+	 * lockpw.c calls us and would cause infinite recursion!
+	 * It is also not used with the prefix option.
+	 */
+	if (!db->setname) {
+		/*
+		 * Call lckpwdf() on the first lock.
+		 * If it succeeds, call *_lock() only once
+		 * (no retries, it should always succeed).
+		 */
+		if (0 == lock_count) {
+			if (lckpwdf () == -1) {
+				if (geteuid () != 0) {
+					(void) fprintf (stderr,
+					                "%s: Permission denied.\n",
+					                Prog);
+				}
+				return 0;	/* failure */
+			}
+		}
+
+		if (commonio_lock_nowait (db, true) != 0) {
+			return 1;	/* success */
+		}
+
+		ulckpwdf ();
+		return 0;		/* failure */
+	}
+#endif				/* !HAVE_LCKPWDF */
+
 	/*
 	 * lckpwdf() not used - do it the old way.
 	 */
@@ -471,7 +474,6 @@ int commonio_lock (struct commonio_db *db)
 		}
 	}
 	return 0;		/* failure */
-#endif				/* !HAVE_LCKPWDF */
 }
 
 static void dec_lock_count (void)

lib/commonio.h

@@ -143,6 +143,7 @@ struct commonio_db {
 	bool isopen:1;
 	bool locked:1;
 	bool readonly:1;
+	bool setname:1;
 };
 
 extern int commonio_setname (struct commonio_db *, const char *);

lib/groupio.c

@@ -139,7 +139,8 @@ static /*@owned@*/struct commonio_db group_db = {
 	false,			/* changed */
 	false,			/* isopen */
 	false,			/* locked */
-	false			/* readonly */
+	false,			/* readonly */
+	false			/* setname */
 };
 
 int gr_setdbname (const char *filename)

lib/pwio.c

@@ -114,7 +114,8 @@ static struct commonio_db passwd_db = {
 	false,			/* changed */
 	false,			/* isopen */
 	false,			/* locked */
-	false			/* readonly */
+	false,			/* readonly */
+	false			/* setname */
 };
 
 int pw_setdbname (const char *filename)

lib/sgroupio.c

@@ -238,7 +238,8 @@ static struct commonio_db gshadow_db = {
 	false,			/* changed */
 	false,			/* isopen */
 	false,			/* locked */
-	false			/* readonly */
+	false,			/* readonly */
+	false			/* setname */
 };
 
 int sgr_setdbname (const char *filename)

lib/shadowio.c

@@ -114,7 +114,8 @@ static struct commonio_db shadow_db = {
 	false,			/* changed */
 	false,			/* isopen */
 	false,			/* locked */
-	false			/* readonly */
+	false,			/* readonly */
+	false			/* setname */
 };
 
 int spw_setdbname (const char *filename)

lib/subordinateio.c

@@ -550,7 +550,8 @@ static struct commonio_db subordinate_uid_db = {
 	false,			/* changed */
 	false,			/* isopen */
 	false,			/* locked */
-	false			/* readonly */
+	false,			/* readonly */
+	false			/* setname */
 };
 
 int sub_uid_setdbname (const char *filename)
@@ -631,7 +632,8 @@ static struct commonio_db subordinate_gid_db = {
 	false,			/* changed */
 	false,			/* isopen */
 	false,			/* locked */
-	false			/* readonly */
+	false,			/* readonly */
+	false			/* setname */
 };
 
 int sub_gid_setdbname (const char *filename)