Annotation of src/usr.bin/wall/ttymsg.c, Revision 1.14
1.14 ! avsm 1: /* $OpenBSD: ttymsg.c,v 1.13 2003/06/26 21:59:10 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
1.14 ! avsm 37: static const char rcsid[] = "$OpenBSD: ttymsg.c,v 1.13 2003/06/26 21:59:10 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>
1.13 deraadt 52:
53: char *ttymsg(struct iovec *, int, char *, int);
1.1 deraadt 54:
55: /*
1.14 ! avsm 56: * Display the contents of a uio structure on a terminal. Used by wall(1)
! 57: * and talkd(8). Forks and finishes in child if write would block,
1.1 deraadt 58: * waiting up to tmout seconds. Returns pointer to error string on unexpected
59: * error; string is not newline-terminated. Various "normal" errors are
60: * ignored (exclusive-use, lack of permission, etc.).
61: */
62: char *
63: ttymsg(iov, iovcnt, line, tmout)
64: struct iovec *iov;
65: int iovcnt;
66: char *line;
67: int tmout;
68: {
69: static char device[MAXNAMLEN] = _PATH_DEV;
70: static char errbuf[1024];
1.9 mpech 71: int cnt, fd, left, wret;
1.1 deraadt 72: struct iovec localiov[6];
73: int forked = 0;
1.5 deraadt 74: struct stat st;
1.7 millert 75: sigset_t mask;
1.1 deraadt 76:
77: if (iovcnt > sizeof(localiov) / sizeof(localiov[0]))
78: return ("too many iov's (change code in wall/ttymsg.c)");
1.3 downsj 79:
80: /*
81: * Ignore lines that start with "ftp" or "uucp".
82: */
1.11 deraadt 83: if ((strncmp(line, "ftp", 3) == 0) ||
84: (strncmp(line, "uucp", 4) == 0))
1.3 downsj 85: return (NULL);
1.1 deraadt 86:
1.11 deraadt 87: (void) strlcpy(device + sizeof(_PATH_DEV) - 1, line,
88: sizeof(device) - (sizeof(_PATH_DEV) - 1));
1.1 deraadt 89: if (strchr(device + sizeof(_PATH_DEV) - 1, '/')) {
90: /* A slash is an attempt to break security... */
91: (void) snprintf(errbuf, sizeof(errbuf), "'/' in \"%s\"",
92: device);
93: return (errbuf);
94: }
1.5 deraadt 95:
1.6 deraadt 96: if (getuid()) {
97: if (stat(device, &st) < 0)
98: return (NULL);
99: if ((st.st_mode & S_IWGRP) == 0)
100: return (NULL);
101: }
1.4 deraadt 102:
1.1 deraadt 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 = open(device, O_WRONLY|O_NONBLOCK, 0)) < 0) {
1.6 deraadt 108: if (errno == EBUSY || errno == EACCES)
1.1 deraadt 109: return (NULL);
110: (void) snprintf(errbuf, sizeof(errbuf),
111: "%s: %s", device, strerror(errno));
112: return (errbuf);
113: }
114:
115: for (cnt = left = 0; cnt < iovcnt; ++cnt)
116: left += iov[cnt].iov_len;
117:
118: for (;;) {
119: wret = writev(fd, iov, iovcnt);
120: if (wret >= left)
121: break;
122: if (wret >= 0) {
123: left -= wret;
124: if (iov != localiov) {
125: bcopy(iov, localiov,
126: iovcnt * sizeof(struct iovec));
127: iov = localiov;
128: }
129: for (cnt = 0; wret >= iov->iov_len; ++cnt) {
130: wret -= iov->iov_len;
131: ++iov;
132: --iovcnt;
133: }
134: if (wret) {
135: iov->iov_base += wret;
136: iov->iov_len -= wret;
137: }
138: continue;
139: }
140: if (errno == EWOULDBLOCK) {
1.10 deraadt 141: int off = 0;
142: pid_t cpid;
1.1 deraadt 143:
144: if (forked) {
145: (void) close(fd);
146: _exit(1);
147: }
148: cpid = fork();
149: if (cpid < 0) {
150: (void) snprintf(errbuf, sizeof(errbuf),
151: "fork: %s", strerror(errno));
152: (void) close(fd);
153: return (errbuf);
154: }
155: if (cpid) { /* parent */
156: (void) close(fd);
157: return (NULL);
158: }
159: forked++;
160: /* wait at most tmout seconds */
161: (void) signal(SIGALRM, SIG_DFL);
162: (void) signal(SIGTERM, SIG_DFL); /* XXX */
1.7 millert 163: (void) sigemptyset(&mask);
164: (void) sigprocmask(SIG_SETMASK, &mask, NULL);
1.1 deraadt 165: (void) alarm((u_int)tmout);
166: (void) fcntl(fd, O_NONBLOCK, &off);
167: continue;
168: }
169: /*
170: * We get ENODEV on a slip line if we're running as root,
171: * and EIO if the line just went away.
172: */
173: if (errno == ENODEV || errno == EIO)
174: break;
175: (void) close(fd);
176: if (forked)
177: _exit(1);
178: (void) snprintf(errbuf, sizeof(errbuf),
179: "%s: %s", device, strerror(errno));
180: return (errbuf);
181: }
182:
183: (void) close(fd);
184: if (forked)
185: _exit(0);
186: return (NULL);
187: }
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