1 /* $OpenBSD: ttymsg.c,v 1.7 2015/07/06 16:12:16 millert Exp $ */ 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. Neither the name of the University nor the names of its contributors 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 #include <sys/param.h> /* nitems */ 34 #include <sys/stat.h> 35 36 #include <signal.h> 37 #include <fcntl.h> 38 #include <dirent.h> 39 #include <errno.h> 40 #include <paths.h> 41 #include <unistd.h> 42 #include <stdio.h> 43 #include <string.h> 44 #include <stdlib.h> 45 46 #include "syslogd.h" 47 48 /* 49 * Display the contents of a uio structure on a terminal. 50 * Forks and finishes in child if write would block, waiting up to tmout 51 * seconds. Returns pointer to error string on unexpected error; 52 * string is not newline-terminated. Various "normal" errors are ignored 53 * (exclusive-use, lack of permission, etc.). 54 */ 55 char * 56 ttymsg(struct iovec *iov, int iovcnt, char *line, int tmout) 57 { 58 static char device[MAXNAMLEN] = _PATH_DEV; 59 static char errbuf[1024]; 60 int cnt, fd, left; 61 ssize_t wret; 62 struct iovec localiov[6]; 63 int forked = 0; 64 sigset_t mask; 65 66 if (iovcnt < 0 || (size_t)iovcnt > nitems(localiov)) 67 return ("too many iov's (change code in syslogd/ttymsg.c)"); 68 69 /* 70 * Ignore lines that start with "ftp" or "uucp". 71 */ 72 if ((strncmp(line, "ftp", 3) == 0) || 73 (strncmp(line, "uucp", 4) == 0)) 74 return (NULL); 75 76 (void) strlcpy(device + sizeof(_PATH_DEV) - 1, line, 77 sizeof(device) - (sizeof(_PATH_DEV) - 1)); 78 if (strchr(device + sizeof(_PATH_DEV) - 1, '/')) { 79 /* A slash is an attempt to break security... */ 80 (void) snprintf(errbuf, sizeof(errbuf), "'/' in \"%s\"", 81 device); 82 return (errbuf); 83 } 84 85 /* 86 * open will fail on slip lines or exclusive-use lines 87 * if not running as root; not an error. 88 */ 89 if ((fd = priv_open_tty(device)) < 0) { 90 if (errno == EBUSY || errno == EACCES) 91 return (NULL); 92 (void) snprintf(errbuf, sizeof(errbuf), 93 "%s: %s", device, strerror(errno)); 94 return (errbuf); 95 } 96 97 for (cnt = left = 0; cnt < iovcnt; ++cnt) 98 left += iov[cnt].iov_len; 99 100 for (;;) { 101 wret = writev(fd, iov, iovcnt); 102 if (wret >= left) 103 break; 104 if (wret >= 0) { 105 left -= wret; 106 if (iov != localiov) { 107 bcopy(iov, localiov, 108 iovcnt * sizeof(struct iovec)); 109 iov = localiov; 110 } 111 for (cnt = 0; (size_t)wret >= iov->iov_len; ++cnt) { 112 wret -= iov->iov_len; 113 ++iov; 114 --iovcnt; 115 } 116 if (wret) { 117 iov->iov_base = (char *)iov->iov_base + wret; 118 iov->iov_len -= wret; 119 } 120 continue; 121 } 122 if (errno == EWOULDBLOCK) { 123 int off = 0; 124 pid_t cpid; 125 126 if (forked) { 127 (void) close(fd); 128 _exit(1); 129 } 130 cpid = fork(); 131 if (cpid < 0) { 132 (void) snprintf(errbuf, sizeof(errbuf), 133 "fork: %s", strerror(errno)); 134 (void) close(fd); 135 return (errbuf); 136 } 137 if (cpid) { /* parent */ 138 (void) close(fd); 139 return (NULL); 140 } 141 forked++; 142 /* wait at most tmout seconds */ 143 (void) signal(SIGALRM, SIG_DFL); 144 (void) signal(SIGTERM, SIG_DFL); /* XXX */ 145 (void) sigemptyset(&mask); 146 (void) sigprocmask(SIG_SETMASK, &mask, NULL); 147 (void) alarm((u_int)tmout); 148 (void) fcntl(fd, O_NONBLOCK, &off); 149 continue; 150 } 151 /* 152 * We get ENODEV on a slip line if we're running as root, 153 * and EIO if the line just went away. 154 */ 155 if (errno == ENODEV || errno == EIO) 156 break; 157 (void) close(fd); 158 if (forked) 159 _exit(1); 160 (void) snprintf(errbuf, sizeof(errbuf), 161 "%s: %s", device, strerror(errno)); 162 return (errbuf); 163 } 164 165 (void) close(fd); 166 if (forked) 167 _exit(0); 168 return (NULL); 169 } 170