+/* vi: set sw=4 ts=4: */
/*
- * mesg implementation for busybox
+ * mesg implementation for busybox
*
- * Copyright (c) 2002 Manuel Novoa III <mjn3@codepoet.org>
+ * Copyright (c) 2002 Manuel Novoa III <mjn3@codepoet.org>
*
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ * Licensed under GPLv2 or later, see file LICENSE in this source tree.
*/
-#include <unistd.h>
-#include <stdlib.h>
-#include "busybox.h"
+//config:config MESG
+//config: bool "mesg"
+//config: default y
+//config: help
+//config: Mesg controls access to your terminal by others. It is typically
+//config: used to allow or disallow other users to write to your terminal
+//config:
+//config:config FEATURE_MESG_ENABLE_ONLY_GROUP
+//config: bool "Enable writing to tty only by group, not by everybody"
+//config: default y
+//config: depends on MESG
+//config: help
+//config: Usually, ttys are owned by group "tty", and "write" tool is
+//config: setgid to this group. This way, "mesg y" only needs to enable
+//config: "write by owning group" bit in tty mode.
+//config:
+//config: If you set this option to N, "mesg y" will enable writing
+//config: by anybody at all. This is not recommended.
+
+//applet:IF_MESG(APPLET(mesg, BB_DIR_USR_BIN, BB_SUID_DROP))
+
+//kbuild:lib-$(CONFIG_MESG) += mesg.o
+
+//usage:#define mesg_trivial_usage
+//usage: "[y|n]"
+//usage:#define mesg_full_usage "\n\n"
+//usage: "Control write access to your terminal\n"
+//usage: " y Allow write access to your terminal\n"
+//usage: " n Disallow write access to your terminal"
-#ifdef USE_TTY_GROUP
-#define S_IWGRP_OR_S_IWOTH S_IWGRP
+#include "libbb.h"
+
+#if ENABLE_FEATURE_MESG_ENABLE_ONLY_GROUP
+#define S_IWGRP_OR_S_IWOTH S_IWGRP
#else
-#define S_IWGRP_OR_S_IWOTH (S_IWGRP | S_IWOTH)
+#define S_IWGRP_OR_S_IWOTH (S_IWGRP | S_IWOTH)
#endif
-int mesg_main(int argc, char *argv[])
+int mesg_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
+int mesg_main(int argc UNUSED_PARAM, char **argv)
{
struct stat sb;
- char *tty;
+ mode_t m;
char c = 0;
- if ((--argc == 0)
- || ((argc == 1) && (((c = **++argv) == 'y') || (c == 'n')))) {
- if ((tty = ttyname(STDERR_FILENO)) == NULL) {
- tty = "ttyname";
- } else if (stat(tty, &sb) == 0) {
- if (argc == 0) {
- puts(((sb.st_mode & (S_IWGRP | S_IWOTH)) ==
- 0) ? "is n" : "is y");
- return EXIT_SUCCESS;
- }
- if (chmod
- (tty,
- (c ==
- 'y') ? sb.st_mode | (S_IWGRP_OR_S_IWOTH) : sb.
- st_mode & ~(S_IWGRP | S_IWOTH)) == 0) {
- return EXIT_SUCCESS;
- }
- }
- bb_perror_msg_and_die("%s", tty);
+ argv++;
+
+ if (argv[0]
+ && (argv[1] || ((c = argv[0][0]) != 'y' && c != 'n'))
+ ) {
+ bb_show_usage();
+ }
+
+ if (!isatty(STDIN_FILENO))
+ bb_error_msg_and_die("not a tty");
+
+ xfstat(STDIN_FILENO, &sb, "stderr");
+ if (c == 0) {
+ puts((sb.st_mode & (S_IWGRP|S_IWOTH)) ? "is y" : "is n");
+ return EXIT_SUCCESS;
}
- bb_show_usage();
+ m = (c == 'y') ? sb.st_mode | S_IWGRP_OR_S_IWOTH
+ : sb.st_mode & ~(S_IWGRP|S_IWOTH);
+ if (fchmod(STDIN_FILENO, m) != 0)
+ bb_perror_nomsg_and_die();
+ return EXIT_SUCCESS;
}