source: MondoRescue/branches/3.3/mindi-busybox/miscutils/wall.c@ 3621

/* vi: set sw=4 ts=4: */
/*
 * wall - write a message to all logged-in users
 * Copyright (c) 2009 Bernhard Reutner-Fischer
 *
 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
 */

//config:config WALL
//config:   bool "wall"
//config:   default y
//config:   depends on FEATURE_UTMP
//config:   help
//config:     Write a message to all users that are logged in.

/* Needs to be run by root or be suid root - needs to write to /dev/TTY: */
//applet:IF_WALL(APPLET(wall, BB_DIR_USR_BIN, BB_SUID_REQUIRE))

//kbuild:lib-$(CONFIG_WALL) += wall.o

//usage:#define wall_trivial_usage
//usage:    "[FILE]"
//usage:#define wall_full_usage "\n\n"
//usage:    "Write content of FILE or stdin to all logged-in users"
//usage:
//usage:#define wall_sample_usage
//usage:    "echo foo | wall\n"
//usage:    "wall ./mymessage"

#include "libbb.h"

int wall_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int wall_main(int argc UNUSED_PARAM, char **argv)
{
    struct utmpx *ut;
    char *msg;
    int fd;

    fd = STDIN_FILENO;
    if (argv[1]) {
        /* The applet is setuid.
         * Access to the file must be under user's uid/gid.
         */
        fd = xopen_as_uid_gid(argv[1], O_RDONLY, getuid(), getgid());
    }
    msg = xmalloc_read(fd, NULL);
    if (ENABLE_FEATURE_CLEAN_UP && argv[1])
        close(fd);
    setutxent();
    while ((ut = getutxent()) != NULL) {
        char *line;
        if (ut->ut_type != USER_PROCESS)
            continue;
        line = concat_path_file("/dev", ut->ut_line);
        xopen_xwrite_close(line, msg);
        free(line);
    }
    if (ENABLE_FEATURE_CLEAN_UP) {
        endutxent();
        free(msg);
    }
    return EXIT_SUCCESS;
}