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