1 /* $OpenBSD: ttymsg.c,v 1.19 2021/09/03 16:28:33 bluhm Exp $ */
2 /* $NetBSD: ttymsg.c,v 1.3 1994/11/17 07:17:55 jtc Exp $ */
3
4 /*
5 * Copyright (c) 2014-2017 Alexander Bluhm <bluhm@genua.de>
6 *
7 * Permission to use, copy, modify, and distribute this software for any
8 * purpose with or without fee is hereby granted, provided that the above
9 * copyright notice and this permission notice appear in all copies.
10 *
11 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
12 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
13 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
14 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
15 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
16 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
17 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
18 */
19
20 /*
21 * Copyright (c) 1989, 1993
22 * The Regents of the University of California. All rights reserved.
23 *
24 * Redistribution and use in source and binary forms, with or without
25 * modification, are permitted provided that the following conditions
26 * are met:
27 * 1. Redistributions of source code must retain the above copyright
28 * notice, this list of conditions and the following disclaimer.
29 * 2. Redistributions in binary form must reproduce the above copyright
30 * notice, this list of conditions and the following disclaimer in the
31 * documentation and/or other materials provided with the distribution.
32 * 3. Neither the name of the University nor the names of its contributors
33 * may be used to endorse or promote products derived from this software
34 * without specific prior written permission.
35 *
36 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
37 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
38 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
39 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
40 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
41 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
42 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
43 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
44 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
45 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
46 * SUCH DAMAGE.
47 */
48
49 #include <sys/stat.h>
50 #include <sys/syslog.h>
51
52 #include <dirent.h>
53 #include <errno.h>
54 #include <event.h>
55 #include <paths.h>
56 #include <signal.h>
57 #include <stdio.h>
58 #include <stdlib.h>
59 #include <string.h>
60 #include <unistd.h>
61
62 #include "log.h"
63 #include "syslogd.h"
64
65 struct tty_delay {
66 struct event td_event;
67 size_t td_length;
68 char td_line[LOG_MAXLINE];
69 };
70 int tty_delayed = 0;
71 void ttycb(int, short, void *);
72
73 /*
74 * Display the contents of a uio structure on a terminal.
75 * Schedules an event if write would block, waiting up to TTYMSGTIME
76 * seconds.
77 */
78 void
ttymsg(char * utline,struct iovec * iov)79 ttymsg(char *utline, struct iovec *iov)
80 {
81 static char device[MAXNAMLEN] = _PATH_DEV;
82 struct iovec localiov[IOVCNT];
83 int iovcnt = IOVCNT;
84 int cnt, fd;
85 size_t left;
86 ssize_t wret;
87
88 /*
89 * Ignore lines that start with "ftp" or "uucp".
90 */
91 if ((strncmp(utline, "ftp", 3) == 0) ||
92 (strncmp(utline, "uucp", 4) == 0))
93 return;
94
95 (void) strlcpy(device + sizeof(_PATH_DEV) - 1, utline,
96 sizeof(device) - (sizeof(_PATH_DEV) - 1));
97 if (strchr(device + sizeof(_PATH_DEV) - 1, '/')) {
98 /* A slash is an attempt to break security... */
99 log_warnx("'/' in tty device \"%s\"", device);
100 return;
101 }
102
103 /*
104 * open will fail on slip lines or exclusive-use lines
105 * if not running as root; not an error.
106 */
107 if ((fd = priv_open_tty(device)) == -1) {
108 if (errno != EBUSY && errno != EACCES)
109 log_warn("priv_open_tty device \"%s\"", device);
110 return;
111 }
112
113 left = 0;
114 for (cnt = 0; cnt < iovcnt; ++cnt)
115 left += iov[cnt].iov_len;
116
117 for (;;) {
118 wret = writev(fd, iov, iovcnt);
119 if (wret >= 0) {
120 if ((size_t)wret >= left)
121 break;
122 left -= wret;
123 if (iov != localiov) {
124 memmove(localiov, iov,
125 iovcnt * sizeof(struct iovec));
126 iov = localiov;
127 }
128 while ((size_t)wret >= iov->iov_len) {
129 wret -= iov->iov_len;
130 ++iov;
131 --iovcnt;
132 }
133 if (wret) {
134 iov->iov_base = (char *)iov->iov_base + wret;
135 iov->iov_len -= wret;
136 }
137 continue;
138 }
139 if (errno == EWOULDBLOCK) {
140 struct tty_delay *td;
141 struct timeval to;
142
143 if (tty_delayed >= TTYMAXDELAY) {
144 log_warnx("tty device \"%s\": %s",
145 device, "too many delayed writes");
146 break;
147 }
148 log_debug("ttymsg delayed write");
149 if (iov != localiov) {
150 memmove(localiov, iov,
151 iovcnt * sizeof(struct iovec));
152 iov = localiov;
153 }
154 if ((td = malloc(sizeof(*td))) == NULL) {
155 log_warn("allocate delay tty device \"%s\"",
156 device);
157 break;
158 }
159 td->td_length = 0;
160 if (left > LOG_MAXLINE)
161 left = LOG_MAXLINE;
162 while (iovcnt && left) {
163 if (iov->iov_len > left)
164 iov->iov_len = left;
165 memcpy(td->td_line + td->td_length,
166 iov->iov_base, iov->iov_len);
167 td->td_length += iov->iov_len;
168 left -= iov->iov_len;
169 ++iov;
170 --iovcnt;
171 }
172 tty_delayed++;
173 event_set(&td->td_event, fd, EV_WRITE, ttycb, td);
174 to.tv_sec = TTYMSGTIME;
175 to.tv_usec = 0;
176 event_add(&td->td_event, &to);
177 return;
178 }
179 /*
180 * We get ENODEV on a slip line if we're running as root,
181 * and EIO if the line just went away.
182 */
183 if (errno != ENODEV && errno != EIO)
184 log_warn("writev tty device \"%s\"", device);
185 break;
186 }
187
188 (void) close(fd);
189 return;
190 }
191
192 void
ttycb(int fd,short event,void * arg)193 ttycb(int fd, short event, void *arg)
194 {
195 struct tty_delay *td = arg;
196 struct timeval to;
197 ssize_t wret;
198
199 if (event != EV_WRITE)
200 goto done;
201
202 wret = write(fd, td->td_line, td->td_length);
203 if (wret == -1 && errno != EINTR && errno != EWOULDBLOCK)
204 goto done;
205 if (wret > 0) {
206 td->td_length -= wret;
207 if (td->td_length == 0)
208 goto done;
209 memmove(td->td_line, td->td_line + wret, td->td_length);
210 }
211 to.tv_sec = TTYMSGTIME;
212 to.tv_usec = 0;
213 event_add(&td->td_event, &to);
214 return;
215
216 done:
217 tty_delayed--;
218 close(fd);
219 free(td);
220 }
221