Annotation of src/usr.bin/wall/ttymsg.c, Revision 1.6
1.6 ! deraadt 1: /* $OpenBSD: ttymsg.c,v 1.5 1998/11/18 02:57:22 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.
16: * 3. All advertising materials mentioning features or use of this software
17: * must display the following acknowledgement:
18: * This product includes software developed by the University of
19: * California, Berkeley and its contributors.
20: * 4. Neither the name of the University nor the names of its contributors
21: * may be used to endorse or promote products derived from this software
22: * without specific prior written permission.
23: *
24: * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25: * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26: * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27: * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28: * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29: * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30: * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31: * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32: * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33: * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34: * SUCH DAMAGE.
35: */
36:
37: #ifndef lint
38: #if 0
39: static char sccsid[] = "@(#)ttymsg.c 8.2 (Berkeley) 11/16/93";
40: #endif
1.6 ! deraadt 41: static char rcsid[] = "$OpenBSD: ttymsg.c,v 1.5 1998/11/18 02:57:22 deraadt Exp $";
1.1 deraadt 42: #endif /* not lint */
43:
44: #include <sys/types.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>
1.4 deraadt 55: #include <sys/stat.h>
1.1 deraadt 56:
57: /*
58: * Display the contents of a uio structure on a terminal. Used by wall(1),
59: * syslogd(8), and talkd(8). Forks and finishes in child if write would block,
60: * waiting up to tmout seconds. Returns pointer to error string on unexpected
61: * error; string is not newline-terminated. Various "normal" errors are
62: * ignored (exclusive-use, lack of permission, etc.).
63: */
64: char *
65: ttymsg(iov, iovcnt, line, tmout)
66: struct iovec *iov;
67: int iovcnt;
68: char *line;
69: int tmout;
70: {
71: static char device[MAXNAMLEN] = _PATH_DEV;
72: static char errbuf[1024];
73: register int cnt, fd, left, wret;
74: struct iovec localiov[6];
75: int forked = 0;
1.5 deraadt 76: struct stat st;
1.1 deraadt 77:
78: if (iovcnt > sizeof(localiov) / sizeof(localiov[0]))
79: return ("too many iov's (change code in wall/ttymsg.c)");
1.3 downsj 80:
81: /*
82: * Ignore lines that start with "ftp" or "uucp".
83: */
84: if ((strncmp(line, "ftp", 3) == 0)
85: || (strncmp(line, "uucp", 4) == 0))
86: return (NULL);
1.1 deraadt 87:
88: (void) strcpy(device + sizeof(_PATH_DEV) - 1, line);
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) {
141: int cpid, off = 0;
142:
143: if (forked) {
144: (void) close(fd);
145: _exit(1);
146: }
147: cpid = fork();
148: if (cpid < 0) {
149: (void) snprintf(errbuf, sizeof(errbuf),
150: "fork: %s", strerror(errno));
151: (void) close(fd);
152: return (errbuf);
153: }
154: if (cpid) { /* parent */
155: (void) close(fd);
156: return (NULL);
157: }
158: forked++;
159: /* wait at most tmout seconds */
160: (void) signal(SIGALRM, SIG_DFL);
161: (void) signal(SIGTERM, SIG_DFL); /* XXX */
162: (void) sigsetmask(0);
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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