1 /*
2 * Copyright (c) 1989, 1993
3 * The Regents of the University of California. All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 * 3. All advertising materials mentioning features or use of this software
14 * must display the following acknowledgement:
15 * This product includes software developed by the University of
16 * California, Berkeley and its contributors.
17 * 4. Neither the name of the University nor the names of its contributors
18 * may be used to endorse or promote products derived from this software
19 * without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
32 *
33 * Modified Sun Mar 12 10:39:22 1995, faith@cs.unc.edu for Linux
34 *
35 */
36
37 /* 1999-02-22 Arkadiusz Miśkiewicz <misiek@pld.ORG.PL>
38 * - added Native Language Support
39 * Sun Mar 21 1999 - Arnaldo Carvalho de Melo <acme@conectiva.com.br>
40 * - fixed strerr(errno) in gettext calls
41 */
42
43 #include <sys/types.h>
44 #include <sys/param.h>
45 #include <sys/uio.h>
46 #include <signal.h>
47 #include <fcntl.h>
48 #include <dirent.h>
49 #include <errno.h>
50 #include <paths.h>
51 #include <unistd.h>
52 #include <stdio.h>
53 #include <string.h>
54 #include <stdlib.h>
55
56 #include "nls.h"
57 #include "closestream.h"
58 #include "pathnames.h"
59 #include "ttymsg.h"
60
61 #define ERR_BUFLEN (MAXNAMLEN + 1024)
62
63 /*
64 * Display the contents of a uio structure on a terminal. Used by wall(1),
65 * syslogd(8), and talkd(8). Forks and finishes in child if write would block,
66 * waiting up to tmout seconds. Returns pointer to error string on unexpected
67 * error; string is not newline-terminated. Various "normal" errors are
68 * ignored (exclusive-use, lack of permission, etc.).
69 */
70 char *
71 ttymsg(struct iovec *iov, size_t iovcnt, char *line, int tmout) {
72 static char device[MAXNAMLEN];
73 static char errbuf[ERR_BUFLEN];
74 size_t cnt, left;
75 ssize_t wret;
76 struct iovec localiov[6];
77 int fd, forked = 0;
78 ssize_t len = 0;
79
80 if (iovcnt > ARRAY_SIZE(localiov)) {
81 snprintf(errbuf, sizeof(errbuf), _("internal error: too many iov's"));
82 return errbuf;
83 }
84
85 /* The old code here rejected the line argument when it contained a '/',
86 saying: "A slash may be an attempt to break security...".
87 However, if a user can control the line argument here
88 then they can make this routine write to /dev/hda or /dev/sda
89 already. So, this test was worthless, and these days it is
90 also wrong since people use /dev/pts/xxx. */
91
92 len = snprintf(device, sizeof(device), "%s%s", _PATH_DEV, line);
93 if (len < 0 || (size_t)len >= sizeof(device)) {
94 snprintf(errbuf, sizeof(errbuf), _("excessively long line arg"));
95 return errbuf;
96 }
97
98 /*
99 * open will fail on slip lines or exclusive-use lines
100 * if not running as root; not an error.
101 */
102 if ((fd = open(device, O_WRONLY|O_NONBLOCK, 0)) < 0) {
103 if (errno == EBUSY || errno == EACCES)
104 return NULL;
105
106 len = snprintf(errbuf, sizeof(errbuf), "%s: %m", device);
107 if (len < 0 || (size_t)len >= sizeof(errbuf))
108 snprintf(errbuf, sizeof(errbuf), _("open failed"));
109 return errbuf;
110 }
111
112 for (cnt = left = 0; cnt < iovcnt; ++cnt)
113 left += iov[cnt].iov_len;
114
115 for (;;) {
116 wret = writev(fd, iov, iovcnt);
117 if (wret >= (ssize_t) left)
118 break;
119 if (wret >= 0) {
120 left -= wret;
121 if (iov != localiov) {
122 memmove(localiov, iov,
123 iovcnt * sizeof(struct iovec));
124 iov = localiov;
125 }
126 for (cnt = 0; wret >= (ssize_t) iov->iov_len; ++cnt) {
127 wret -= iov->iov_len;
128 ++iov;
129 --iovcnt;
130 }
131 if (wret) {
132 iov->iov_base = (char *) iov->iov_base + wret;
133 iov->iov_len -= wret;
134 }
135 continue;
136 }
137 if (errno == EWOULDBLOCK) {
138 int cpid, flags;
139 sigset_t sigmask;
140
141 if (forked) {
142 close(fd);
143 _exit(EXIT_FAILURE);
144 }
145 cpid = fork();
146 if (cpid < 0) {
147 len = snprintf(errbuf, sizeof(errbuf), _("fork: %m"));
148 if (len < 0 || (size_t)len >= sizeof(errbuf))
149 snprintf(errbuf, sizeof(errbuf), _("cannot fork"));
150 close(fd);
151 return errbuf;
152 }
153 if (cpid) { /* parent */
154 close(fd);
155 return NULL;
156 }
157 forked++;
158 /* wait at most tmout seconds */
159 signal(SIGALRM, SIG_DFL);
160 signal(SIGTERM, SIG_DFL); /* XXX */
161 sigemptyset(&sigmask);
162 sigprocmask (SIG_SETMASK, &sigmask, NULL);
163 alarm((u_int)tmout);
164 flags = fcntl(fd, F_GETFL);
165 fcntl(flags, F_SETFL, (long) (flags & ~O_NONBLOCK));
166 continue;
167 }
168 /*
169 * We get ENODEV on a slip line if we're running as root,
170 * and EIO if the line just went away.
171 */
172 if (errno == ENODEV || errno == EIO)
173 break;
174 if (close_fd(fd) != 0)
175 warn(_("write failed: %s"), device);
176 if (forked)
177 _exit(EXIT_FAILURE);
178
179 len = snprintf(errbuf, sizeof(errbuf), "%s: %m", device);
180 if (len < 0 || (size_t)len >= sizeof(errbuf))
181 snprintf(errbuf, sizeof(errbuf),
182 _("%s: BAD ERROR, message is "
183 "far too long"), device);
184 return errbuf;
185 }
186
187 close(fd);
188
189 if (forked)
190 _exit(EXIT_SUCCESS);
191 return NULL;
192 }