Add keepopen arg to open_sudoers that open_sudoers can use to

indicate to the caller that the fd should not be closed when it
is done with it.  To be used by visudo to keep locked fds from
being closed prematurely (and thus losing the lock).

parse.lex

@@ -523,6 +523,7 @@ buffer_frob(path)
 {
     static size_t stacksize, depth;
     static struct sudoers_state *state;
+    static int keepopen;
     FILE *fp;
 
     if (path != NULL) {
@@ -542,7 +543,7 @@ buffer_frob(path)
 		return(FALSE);
 	    }
 	}
-	if ((fp = open_sudoers(path)) == NULL) {
+	if ((fp = open_sudoers(path, &keepopen)) == NULL) {
 	    yyerror(path);
 	    return(FALSE);
 	}
@@ -558,12 +559,14 @@ buffer_frob(path)
 	if (depth == 0)
 	    return(FALSE);
 	depth--;
-	fclose(YY_CURRENT_BUFFER->yy_input_file);
+	if (!keepopen)
+	    fclose(YY_CURRENT_BUFFER->yy_input_file);
 	yy_delete_buffer(YY_CURRENT_BUFFER);
 	yy_switch_to_buffer(state[depth].bs);
 	free(sudoers);
 	sudoers = state[depth].path;
 	sudolineno = state[depth].lineno;
+	keepopen = FALSE;
     }
     return(TRUE);
 }

sudo.c

@@ -259,7 +259,7 @@ main(argc, argv, envp)
     else if (ISSET(validated, VALIDATE_OK) && !printmatches); /* skips */
     else if (ISSET(validated, VALIDATE_OK) && printmatches)
     {
-	sudoers_fp = open_sudoers(_PATH_SUDOERS);
+	sudoers_fp = open_sudoers(_PATH_SUDOERS, NULL);
 
 	/* User is found in LDAP and we want a list of all sudo commands the
 	 * user can do, so consult sudoers but throw away result.
@@ -269,7 +269,7 @@ main(argc, argv, envp)
     else
 #endif
     {
-	sudoers_fp = open_sudoers(_PATH_SUDOERS);
+	sudoers_fp = open_sudoers(_PATH_SUDOERS, NULL);
 
 	/* Validate the user but don't search for pseudo-commands. */
 	validated = sudoers_lookup(pwflag);
@@ -852,8 +852,9 @@ parse_args(argc, argv)
  * Returns a handle to the sudoers file.
  */
 FILE *
-open_sudoers(sudoers)
+open_sudoers(sudoers, keepopen)
     const char *sudoers;
+    int *keepopen;
 {
     struct stat statbuf;
     FILE *fp = NULL;

sudo.h

@@ -238,7 +238,7 @@ char *sudo_getepw	__P((const struct passwd *));
 int pam_prep_user	__P((struct passwd *));
 void zero_bytes		__P((volatile VOID *, size_t));
 int gettime		__P((struct timespec *));
-FILE *open_sudoers	__P((const char *));
+FILE *open_sudoers	__P((const char *, int *));
 YY_DECL;
 #ifdef HAVE_SYSTRACE
 void systrace_attach	__P((pid_t));

testsudoers.c

@@ -336,8 +336,9 @@ set_runaspw(user)
 }
 
 FILE *
-open_sudoers(path)
+open_sudoers(path, keepopen)
     const char *path;
+    int *keepopen;
 {
     return(fopen(path, "r"));
 }

visudo.c

@@ -722,8 +722,9 @@ check_syntax(sudoers_path)
 }
 
 FILE *
-open_sudoers(path)
+open_sudoers(path, keepopen)
     const char *path;
+    int *keepopen;
 {
     FILE *fp;
     struct sudoersfile *newfile;