81 lines
2.2 KiB
C
81 lines
2.2 KiB
C
/* vi: set sw=4 ts=4: */
|
|
/*
|
|
* mesg implementation for busybox
|
|
*
|
|
* Copyright (c) 2002 Manuel Novoa III <mjn3@codepoet.org>
|
|
*
|
|
* Licensed under GPLv2 or later, see file LICENSE in this source tree.
|
|
*/
|
|
//config:config MESG
|
|
//config: bool "mesg (1.4 kb)"
|
|
//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_NOFORK(mesg, mesg, BB_DIR_USR_BIN, BB_SUID_DROP, mesg))
|
|
|
|
//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"
|
|
|
|
#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)
|
|
#endif
|
|
|
|
int mesg_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
|
|
int mesg_main(int argc UNUSED_PARAM, char **argv)
|
|
{
|
|
struct stat sb;
|
|
mode_t m;
|
|
char c = 0;
|
|
|
|
argv++;
|
|
|
|
if (argv[0]
|
|
&& (argv[1] || ((c = argv[0][0]) != 'y' && c != 'n'))
|
|
) {
|
|
bb_show_usage();
|
|
}
|
|
|
|
/* We are a NOFORK applet.
|
|
* (Not that it's very useful, but code is trivially NOFORK-safe).
|
|
* Play nice. Do not leak anything.
|
|
*/
|
|
|
|
if (!isatty(STDIN_FILENO))
|
|
bb_error_msg_and_die("not a tty");
|
|
|
|
xfstat(STDIN_FILENO, &sb, "stdin");
|
|
if (c == 0) {
|
|
puts((sb.st_mode & (S_IWGRP|S_IWOTH)) ? "is y" : "is n");
|
|
return EXIT_SUCCESS;
|
|
}
|
|
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;
|
|
}
|