Annotation of src/usr.bin/wall/ttymsg.c, Revision 1.12
1.12 ! millert 1: /* $OpenBSD: ttymsg.c,v 1.11 2003/04/02 20:07:49 deraadt Exp $ */
1.1 deraadt 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.
1.12 ! millert 16: * 3. Neither the name of the University nor the names of its contributors
1.1 deraadt 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
1.8 millert 35: static const char sccsid[] = "@(#)ttymsg.c 8.2 (Berkeley) 11/16/93";
1.1 deraadt 36: #endif
1.12 ! millert 37: static const char rcsid[] = "$OpenBSD: ttymsg.c,v 1.11 2003/04/02 20:07:49 deraadt Exp $";
1.1 deraadt 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>
1.4 deraadt 51: #include <sys/stat.h>
1.1 deraadt 52:
53: /*
54: * Display the contents of a uio structure on a terminal. Used by wall(1),
55: * syslogd(8), and talkd(8). Forks and finishes in child if write would block,
56: * waiting up to tmout seconds. Returns pointer to error string on unexpected
57: * error; string is not newline-terminated. Various "normal" errors are
58: * ignored (exclusive-use, lack of permission, etc.).
59: */
60: char *
61: ttymsg(iov, iovcnt, line, tmout)
62: struct iovec *iov;
63: int iovcnt;
64: char *line;
65: int tmout;
66: {
67: static char device[MAXNAMLEN] = _PATH_DEV;
68: static char errbuf[1024];
1.9 mpech 69: int cnt, fd, left, wret;
1.1 deraadt 70: struct iovec localiov[6];
71: int forked = 0;
1.5 deraadt 72: struct stat st;
1.7 millert 73: sigset_t mask;
1.1 deraadt 74:
75: if (iovcnt > sizeof(localiov) / sizeof(localiov[0]))
76: return ("too many iov's (change code in wall/ttymsg.c)");
1.3 downsj 77:
78: /*
79: * Ignore lines that start with "ftp" or "uucp".
80: */
1.11 deraadt 81: if ((strncmp(line, "ftp", 3) == 0) ||
82: (strncmp(line, "uucp", 4) == 0))
1.3 downsj 83: return (NULL);
1.1 deraadt 84:
1.11 deraadt 85: (void) strlcpy(device + sizeof(_PATH_DEV) - 1, line,
86: sizeof(device) - (sizeof(_PATH_DEV) - 1));
1.1 deraadt 87: if (strchr(device + sizeof(_PATH_DEV) - 1, '/')) {
88: /* A slash is an attempt to break security... */
89: (void) snprintf(errbuf, sizeof(errbuf), "'/' in \"%s\"",
90: device);
91: return (errbuf);
92: }
1.5 deraadt 93:
1.6 deraadt 94: if (getuid()) {
95: if (stat(device, &st) < 0)
96: return (NULL);
97: if ((st.st_mode & S_IWGRP) == 0)
98: return (NULL);
99: }
1.4 deraadt 100:
1.1 deraadt 101: /*
102: * open will fail on slip lines or exclusive-use lines
103: * if not running as root; not an error.
104: */
105: if ((fd = open(device, O_WRONLY|O_NONBLOCK, 0)) < 0) {
1.6 deraadt 106: if (errno == EBUSY || errno == EACCES)
1.1 deraadt 107: return (NULL);
108: (void) snprintf(errbuf, sizeof(errbuf),
109: "%s: %s", device, strerror(errno));
110: return (errbuf);
111: }
112:
113: for (cnt = left = 0; cnt < iovcnt; ++cnt)
114: left += iov[cnt].iov_len;
115:
116: for (;;) {
117: wret = writev(fd, iov, iovcnt);
118: if (wret >= left)
119: break;
120: if (wret >= 0) {
121: left -= wret;
122: if (iov != localiov) {
123: bcopy(iov, localiov,
124: iovcnt * sizeof(struct iovec));
125: iov = localiov;
126: }
127: for (cnt = 0; wret >= iov->iov_len; ++cnt) {
128: wret -= iov->iov_len;
129: ++iov;
130: --iovcnt;
131: }
132: if (wret) {
133: iov->iov_base += wret;
134: iov->iov_len -= wret;
135: }
136: continue;
137: }
138: if (errno == EWOULDBLOCK) {
1.10 deraadt 139: int off = 0;
140: pid_t cpid;
1.1 deraadt 141:
142: if (forked) {
143: (void) close(fd);
144: _exit(1);
145: }
146: cpid = fork();
147: if (cpid < 0) {
148: (void) snprintf(errbuf, sizeof(errbuf),
149: "fork: %s", strerror(errno));
150: (void) close(fd);
151: return (errbuf);
152: }
153: if (cpid) { /* parent */
154: (void) close(fd);
155: return (NULL);
156: }
157: forked++;
158: /* wait at most tmout seconds */
159: (void) signal(SIGALRM, SIG_DFL);
160: (void) signal(SIGTERM, SIG_DFL); /* XXX */
1.7 millert 161: (void) sigemptyset(&mask);
162: (void) sigprocmask(SIG_SETMASK, &mask, NULL);
1.1 deraadt 163: (void) alarm((u_int)tmout);
164: (void) fcntl(fd, O_NONBLOCK, &off);
165: continue;
166: }
167: /*
168: * We get ENODEV on a slip line if we're running as root,
169: * and EIO if the line just went away.
170: */
171: if (errno == ENODEV || errno == EIO)
172: break;
173: (void) close(fd);
174: if (forked)
175: _exit(1);
176: (void) snprintf(errbuf, sizeof(errbuf),
177: "%s: %s", device, strerror(errno));
178: return (errbuf);
179: }
180:
181: (void) close(fd);
182: if (forked)
183: _exit(0);
184: return (NULL);
185: }
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