blob: 50658f457d820b0503a1d5ad639b4f022e95357a
1 | /* vi: set sw=4 ts=4: */ |
2 | /* |
3 | * wall - write a message to all logged-in users |
4 | * Copyright (c) 2009 Bernhard Reutner-Fischer |
5 | * |
6 | * Licensed under GPLv2 or later, see file LICENSE in this source tree. |
7 | */ |
8 | |
9 | //config:config WALL |
10 | //config: bool "wall" |
11 | //config: default y |
12 | //config: depends on FEATURE_UTMP |
13 | //config: help |
14 | //config: Write a message to all users that are logged in. |
15 | |
16 | /* Needs to be run by root or be suid root - needs to write to /dev/TTY: */ |
17 | //applet:IF_WALL(APPLET(wall, BB_DIR_USR_BIN, BB_SUID_REQUIRE)) |
18 | |
19 | //kbuild:lib-$(CONFIG_WALL) += wall.o |
20 | |
21 | //usage:#define wall_trivial_usage |
22 | //usage: "[FILE]" |
23 | //usage:#define wall_full_usage "\n\n" |
24 | //usage: "Write content of FILE or stdin to all logged-in users" |
25 | //usage: |
26 | //usage:#define wall_sample_usage |
27 | //usage: "echo foo | wall\n" |
28 | //usage: "wall ./mymessage" |
29 | |
30 | #include "libbb.h" |
31 | |
32 | int wall_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; |
33 | int wall_main(int argc UNUSED_PARAM, char **argv) |
34 | { |
35 | struct utmpx *ut; |
36 | char *msg; |
37 | int fd; |
38 | |
39 | fd = STDIN_FILENO; |
40 | if (argv[1]) { |
41 | /* The applet is setuid. |
42 | * Access to the file must be under user's uid/gid. |
43 | */ |
44 | fd = xopen_as_uid_gid(argv[1], O_RDONLY, getuid(), getgid()); |
45 | } |
46 | msg = xmalloc_read(fd, NULL); |
47 | if (ENABLE_FEATURE_CLEAN_UP && argv[1]) |
48 | close(fd); |
49 | setutxent(); |
50 | while ((ut = getutxent()) != NULL) { |
51 | char *line; |
52 | if (ut->ut_type != USER_PROCESS) |
53 | continue; |
54 | line = concat_path_file("/dev", ut->ut_line); |
55 | xopen_xwrite_close(line, msg); |
56 | free(line); |
57 | } |
58 | if (ENABLE_FEATURE_CLEAN_UP) { |
59 | endutxent(); |
60 | free(msg); |
61 | } |
62 | return EXIT_SUCCESS; |
63 | } |
64 |