1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
|
/*
* broadcast.c
* broadcast a message to every logged in user
*/
/*
* Copyright 2018 Sony Interactive Entertainment Inc.
*
* This file is part of OpenRC. It is subject to the license terms in
* the LICENSE file found in the top-level directory of this
* distribution and at https://github.com/OpenRC/openrc/blob/HEAD/LICENSE
* This file may not be copied, modified, propagated, or distributed
* except according to the terms contained in the LICENSE file.
*/
#include <fcntl.h>
#include <paths.h>
#include <pwd.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/stat.h>
#include <sys/sysmacros.h>
#include <sys/types.h>
#include <sys/utsname.h>
#include <time.h>
#include <unistd.h>
#include <utmpx.h>
#include "broadcast.h"
#include "helpers.h"
#ifndef _PATH_DEV
# define _PATH_DEV "/dev/"
#endif
static void getuidtty(char **userp, char **ttyp)
{
struct passwd *pwd;
uid_t uid;
char *tty;
static char uidbuf[32];
char *ttynm = NULL;
uid = getuid();
if ((pwd = getpwuid(uid)) != NULL) {
uidbuf[0] = 0;
strncat(uidbuf, pwd->pw_name, sizeof(uidbuf) - 1);
} else {
if (uid)
sprintf(uidbuf, "uid %d", (int) uid);
else
sprintf(uidbuf, "root");
}
if ((tty = ttyname(0)) != NULL) {
const size_t plen = strlen(_PATH_DEV);
if (strncmp(tty, _PATH_DEV, plen) == 0) {
tty += plen;
if (tty[0] == '/')
tty++;
}
xasprintf(&ttynm, "(%s) ", tty);
}
*userp = uidbuf;
*ttyp = ttynm;
}
/*
* Check whether the given filename looks like a tty device.
*/
static int file_isatty(const char *fname)
{
struct stat st;
int major;
if (stat(fname, &st) < 0)
return 0;
if (st.st_nlink != 1 || !S_ISCHR(st.st_mode))
return 0;
/*
* It would be an impossible task to list all major/minors
* of tty devices here, so we just exclude the obvious
* majors of which just opening has side-effects:
* printers and tapes.
*/
major = major(st.st_dev);
if (major == 1 || major == 2 || major == 6 || major == 9 ||
major == 12 || major == 16 || major == 21 || major == 27 ||
major == 37 || major == 96 || major == 97 || major == 206 ||
major == 230)
return 0;
return 1;
}
/*
* broadcast function.
*
* NB: Not multithread safe.
*/
void broadcast(char *text)
{
char *tty;
char *user;
struct utsname name;
time_t t;
char *date;
char *p;
char *line = NULL;
int len;
int fd;
char *term = NULL;
struct utmpx *utmp;
getuidtty(&user, &tty);
/*
* Get and report current hostname, to make it easier to find out
* which machine is being shut down.
*/
uname(&name);
/* Get the time */
time(&t);
date = ctime(&t);
p = strchr(date, '\n');
if (p)
*p = 0;
len = xasprintf(&line, "\007\r\nBroadcast message from %s@%s %s(%s):\r\n\r\n%s",
user, name.nodename, tty, date, text);
free(tty);
/*
* Fork to avoid hanging in a write()
*/
if (fork() != 0)
return;
setutxent();
while ((utmp = getutxent()) != NULL) {
if (utmp->ut_type != USER_PROCESS || utmp->ut_user[0] == 0)
continue;
if (strncmp(utmp->ut_line, _PATH_DEV, strlen(_PATH_DEV)) == 0)
xasprintf(&term, "%s", utmp->ut_line);
else
xasprintf(&term, "%s%s", _PATH_DEV, utmp->ut_line);
if (strstr(term, "/../")) {
free(term);
continue;
}
/* Open it non-delay */
if (file_isatty(term) && (fd = open(term, O_WRONLY|O_NDELAY|O_NOCTTY)) >= 0) {
if (isatty(fd))
write(fd, line, len);
close(fd);
}
free(term);
}
endutxent();
free(line);
exit(0);
}
|
