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15637ed4 RG |
1 | /* |
2 | * Copyright (c) 1989 The Regents of the University of California. | |
3 | * 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 | ||
34 | #ifndef lint | |
35 | static char sccsid[] = "@(#)ttymsg.c 5.8 (Berkeley) 7/1/91"; | |
36 | #endif /* not lint */ | |
37 | ||
38 | #include <sys/types.h> | |
39 | #include <sys/uio.h> | |
40 | #include <signal.h> | |
41 | #include <fcntl.h> | |
42 | #include <dirent.h> | |
43 | #include <errno.h> | |
44 | #include <paths.h> | |
45 | #include <unistd.h> | |
46 | #include <stdio.h> | |
47 | #include <string.h> | |
48 | #include <stdlib.h> | |
49 | ||
50 | /* | |
51 | * Display the contents of a uio structure on a terminal. Used by wall(1) | |
52 | * and syslogd(8). Forks and finishes in child if write would block, waiting | |
53 | * at most five minutes. Returns pointer to error string on unexpected error; | |
54 | * string is not newline-terminated. Various "normal" errors are ignored | |
55 | * (exclusive-use, lack of permission, etc.). | |
56 | */ | |
57 | char * | |
58 | ttymsg(iov, iovcnt, line) | |
59 | struct iovec *iov; | |
60 | int iovcnt; | |
61 | char *line; | |
62 | { | |
63 | static char device[MAXNAMLEN] = _PATH_DEV; | |
64 | static char errbuf[1024]; | |
65 | register int cnt, fd, left, wret; | |
66 | struct iovec localiov[6]; | |
67 | int forked = 0; | |
68 | ||
69 | if (iovcnt > 6) | |
70 | return ("too many iov's (change code in wall/ttymsg.c)"); | |
71 | /* | |
72 | * open will fail on slip lines or exclusive-use lines | |
73 | * if not running as root; not an error. | |
74 | */ | |
75 | (void) strcpy(device + sizeof(_PATH_DEV) - 1, line); | |
76 | if ((fd = open(device, O_WRONLY|O_NONBLOCK, 0)) < 0) { | |
77 | if (errno == EBUSY || errno == EACCES) | |
78 | return (NULL); | |
79 | (void) snprintf(errbuf, sizeof(errbuf), | |
80 | "%s: %s", device, strerror(errno)); | |
81 | return (errbuf); | |
82 | } | |
83 | ||
84 | for (cnt = left = 0; cnt < iovcnt; ++cnt) | |
85 | left += iov[cnt].iov_len; | |
86 | ||
87 | for (;;) { | |
88 | wret = writev(fd, iov, iovcnt); | |
89 | if (wret >= left) | |
90 | break; | |
91 | if (wret >= 0) { | |
92 | left -= wret; | |
93 | if (iov != localiov) { | |
94 | bcopy(iov, localiov, | |
95 | iovcnt * sizeof(struct iovec)); | |
96 | iov = localiov; | |
97 | } | |
98 | for (cnt = 0; wret >= iov->iov_len; ++cnt) { | |
99 | wret -= iov->iov_len; | |
100 | ++iov; | |
101 | --iovcnt; | |
102 | } | |
103 | if (wret) { | |
104 | iov->iov_base += wret; | |
105 | iov->iov_len -= wret; | |
106 | } | |
107 | continue; | |
108 | } | |
109 | if (errno == EWOULDBLOCK) { | |
110 | int cpid, off = 0; | |
111 | ||
112 | if (forked) { | |
113 | (void) close(fd); | |
114 | _exit(1); | |
115 | } | |
116 | cpid = fork(); | |
117 | if (cpid < 0) { | |
118 | (void) snprintf(errbuf, sizeof(errbuf), | |
119 | "fork: %s", strerror(errno)); | |
120 | (void) close(fd); | |
121 | return (errbuf); | |
122 | } | |
123 | if (cpid) { /* parent */ | |
124 | (void) close(fd); | |
125 | return (NULL); | |
126 | } | |
127 | forked++; | |
128 | /* wait at most 5 minutes */ | |
129 | (void) signal(SIGALRM, SIG_DFL); | |
130 | (void) signal(SIGTERM, SIG_DFL); /* XXX */ | |
131 | (void) sigsetmask(0); | |
132 | (void) alarm((u_int)(60 * 5)); | |
133 | (void) fcntl(fd, O_NONBLOCK, &off); | |
134 | continue; | |
135 | } | |
136 | /* | |
137 | * We get ENODEV on a slip line if we're running as root, | |
138 | * and EIO if the line just went away. | |
139 | */ | |
140 | if (errno == ENODEV || errno == EIO) | |
141 | break; | |
142 | (void) close(fd); | |
143 | if (forked) | |
144 | _exit(1); | |
145 | (void) snprintf(errbuf, sizeof(errbuf), | |
146 | "%s: %s", device, strerror(errno)); | |
147 | return (errbuf); | |
148 | } | |
149 | ||
150 | (void) close(fd); | |
151 | if (forked) | |
152 | _exit(0); | |
153 | return (NULL); | |
154 | } |