1 /* $OpenBSD: ttymsg.c,v 1.3 2004/07/03 23:40:44 djm Exp $ */
2 /* $NetBSD: ttymsg.c,v 1.3 1994/11/17 07:17:55 jtc Exp $ */
3
4 /*
5 * Copyright (c) 1989, 1993
6 * The Regents of the University of California. All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 * 3. Neither the name of the University nor the names of its contributors
17 * may be used to endorse or promote products derived from this software
18 * without specific prior written permission.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30 * SUCH DAMAGE.
31 */
32
33 #ifndef lint
34 #if 0
35 static const char sccsid[] = "@(#)ttymsg.c 8.2 (Berkeley) 11/16/93";
36 #endif
37 static const char rcsid[] = "$OpenBSD: ttymsg.c,v 1.3 2004/07/03 23:40:44 djm Exp $";
38 #endif /* not lint */
39
40 #include <sys/types.h>
41 #include <sys/uio.h>
42 #include <signal.h>
43 #include <fcntl.h>
44 #include <dirent.h>
45 #include <errno.h>
46 #include <paths.h>
47 #include <unistd.h>
48 #include <stdio.h>
49 #include <string.h>
50 #include <stdlib.h>
51 #include <sys/stat.h>
52
53 #include "syslogd.h"
54
55 /*
56 * Display the contents of a uio structure on a terminal.
57 * Forks and finishes in child if write would block, waiting up to tmout
58 * seconds. Returns pointer to error string on unexpected error;
59 * string is not newline-terminated. Various "normal" errors are ignored
60 * (exclusive-use, lack of permission, etc.).
61 */
62 char *
ttymsg(struct iovec * iov,int iovcnt,char * line,int tmout)63 ttymsg(struct iovec *iov, int iovcnt, char *line, int tmout)
64 {
65 static char device[MAXNAMLEN] = _PATH_DEV;
66 static char errbuf[1024];
67 int cnt, fd, left, wret;
68 struct iovec localiov[6];
69 int forked = 0;
70 sigset_t mask;
71
72 if (iovcnt > sizeof(localiov) / sizeof(localiov[0]))
73 return ("too many iov's (change code in syslogd/ttymsg.c)");
74
75 /*
76 * Ignore lines that start with "ftp" or "uucp".
77 */
78 if ((strncmp(line, "ftp", 3) == 0) ||
79 (strncmp(line, "uucp", 4) == 0))
80 return (NULL);
81
82 (void) strlcpy(device + sizeof(_PATH_DEV) - 1, line,
83 sizeof(device) - (sizeof(_PATH_DEV) - 1));
84 if (strchr(device + sizeof(_PATH_DEV) - 1, '/')) {
85 /* A slash is an attempt to break security... */
86 (void) snprintf(errbuf, sizeof(errbuf), "'/' in \"%s\"",
87 device);
88 return (errbuf);
89 }
90
91 /*
92 * open will fail on slip lines or exclusive-use lines
93 * if not running as root; not an error.
94 */
95 if ((fd = priv_open_tty(device)) < 0) {
96 if (errno == EBUSY || errno == EACCES)
97 return (NULL);
98 (void) snprintf(errbuf, sizeof(errbuf),
99 "%s: %s", device, strerror(errno));
100 return (errbuf);
101 }
102
103 for (cnt = left = 0; cnt < iovcnt; ++cnt)
104 left += iov[cnt].iov_len;
105
106 for (;;) {
107 wret = writev(fd, iov, iovcnt);
108 if (wret >= left)
109 break;
110 if (wret >= 0) {
111 left -= wret;
112 if (iov != localiov) {
113 memmove(localiov, iov,
114 iovcnt * sizeof(struct iovec));
115 iov = localiov;
116 }
117 for (cnt = 0; wret >= iov->iov_len; ++cnt) {
118 wret -= iov->iov_len;
119 ++iov;
120 --iovcnt;
121 }
122 if (wret) {
123 iov->iov_base = (char *)iov->iov_base + wret;
124 iov->iov_len -= wret;
125 }
126 continue;
127 }
128 if (errno == EWOULDBLOCK) {
129 int off = 0;
130 pid_t cpid;
131
132 if (forked) {
133 (void) close(fd);
134 _exit(1);
135 }
136 cpid = fork();
137 if (cpid < 0) {
138 (void) snprintf(errbuf, sizeof(errbuf),
139 "fork: %s", strerror(errno));
140 (void) close(fd);
141 return (errbuf);
142 }
143 if (cpid) { /* parent */
144 (void) close(fd);
145 return (NULL);
146 }
147 forked++;
148 /* wait at most tmout seconds */
149 (void) signal(SIGALRM, SIG_DFL);
150 (void) signal(SIGTERM, SIG_DFL); /* XXX */
151 (void) sigemptyset(&mask);
152 (void) sigprocmask(SIG_SETMASK, &mask, NULL);
153 (void) alarm((u_int)tmout);
154 (void) fcntl(fd, O_NONBLOCK, &off);
155 continue;
156 }
157 /*
158 * We get ENODEV on a slip line if we're running as root,
159 * and EIO if the line just went away.
160 */
161 if (errno == ENODEV || errno == EIO)
162 break;
163 (void) close(fd);
164 if (forked)
165 _exit(1);
166 (void) snprintf(errbuf, sizeof(errbuf),
167 "%s: %s", device, strerror(errno));
168 return (errbuf);
169 }
170
171 (void) close(fd);
172 if (forked)
173 _exit(0);
174 return (NULL);
175 }
176