1 /* $OpenBSD: ttymsg.c,v 1.18 2019/06/28 13:32:51 deraadt Exp $ */ 2 /* $NetBSD: ttymsg.c,v 1.3 1994/11/17 07:17:55 jtc Exp $ */ 3 4 /* 5 * Copyright (c) 2014-2017 Alexander Bluhm <bluhm@genua.de> 6 * 7 * Permission to use, copy, modify, and distribute this software for any 8 * purpose with or without fee is hereby granted, provided that the above 9 * copyright notice and this permission notice appear in all copies. 10 * 11 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES 12 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF 13 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR 14 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 15 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN 16 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF 17 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 18 */ 19 20 /* 21 * Copyright (c) 1989, 1993 22 * The Regents of the University of California. All rights reserved. 23 * 24 * Redistribution and use in source and binary forms, with or without 25 * modification, are permitted provided that the following conditions 26 * are met: 27 * 1. Redistributions of source code must retain the above copyright 28 * notice, this list of conditions and the following disclaimer. 29 * 2. Redistributions in binary form must reproduce the above copyright 30 * notice, this list of conditions and the following disclaimer in the 31 * documentation and/or other materials provided with the distribution. 32 * 3. Neither the name of the University nor the names of its contributors 33 * may be used to endorse or promote products derived from this software 34 * without specific prior written permission. 35 * 36 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 37 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 38 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 39 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 40 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 41 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 42 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 43 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 44 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 45 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 46 * SUCH DAMAGE. 47 */ 48 49 #include <sys/stat.h> 50 #include <sys/syslog.h> 51 52 #include <dirent.h> 53 #include <errno.h> 54 #include <event.h> 55 #include <paths.h> 56 #include <signal.h> 57 #include <stdio.h> 58 #include <stdlib.h> 59 #include <string.h> 60 #include <unistd.h> 61 62 #include "log.h" 63 #include "syslogd.h" 64 65 #ifndef nitems 66 #define nitems(_a) (sizeof((_a)) / sizeof((_a)[0])) 67 #endif 68 69 struct tty_delay { 70 struct event td_event; 71 size_t td_length; 72 char td_line[LOG_MAXLINE]; 73 }; 74 int tty_delayed = 0; 75 void ttycb(int, short, void *); 76 77 /* 78 * Display the contents of a uio structure on a terminal. 79 * Schedules an event if write would block, waiting up to TTYMSGTIME 80 * seconds. 81 */ 82 void 83 ttymsg(struct iovec *iov, int iovcnt, char *utline) 84 { 85 static char device[MAXNAMLEN] = _PATH_DEV; 86 int cnt, fd; 87 size_t left; 88 ssize_t wret; 89 struct iovec localiov[6]; 90 91 if (iovcnt < 0 || (size_t)iovcnt > nitems(localiov)) { 92 log_warnx("too many iov's (change code in syslogd/ttymsg.c)"); 93 return; 94 } 95 96 /* 97 * Ignore lines that start with "ftp" or "uucp". 98 */ 99 if ((strncmp(utline, "ftp", 3) == 0) || 100 (strncmp(utline, "uucp", 4) == 0)) 101 return; 102 103 (void) strlcpy(device + sizeof(_PATH_DEV) - 1, utline, 104 sizeof(device) - (sizeof(_PATH_DEV) - 1)); 105 if (strchr(device + sizeof(_PATH_DEV) - 1, '/')) { 106 /* A slash is an attempt to break security... */ 107 log_warnx("'/' in tty device \"%s\"", device); 108 return; 109 } 110 111 /* 112 * open will fail on slip lines or exclusive-use lines 113 * if not running as root; not an error. 114 */ 115 if ((fd = priv_open_tty(device)) == -1) { 116 if (errno != EBUSY && errno != EACCES) 117 log_warn("priv_open_tty device \"%s\"", device); 118 return; 119 } 120 121 left = 0; 122 for (cnt = 0; cnt < iovcnt; ++cnt) 123 left += iov[cnt].iov_len; 124 125 for (;;) { 126 wret = writev(fd, iov, iovcnt); 127 if (wret >= 0) { 128 if ((size_t)wret >= left) 129 break; 130 left -= wret; 131 if (iov != localiov) { 132 memmove(localiov, iov, 133 iovcnt * sizeof(struct iovec)); 134 iov = localiov; 135 } 136 while ((size_t)wret >= iov->iov_len) { 137 wret -= iov->iov_len; 138 ++iov; 139 --iovcnt; 140 } 141 if (wret) { 142 iov->iov_base = (char *)iov->iov_base + wret; 143 iov->iov_len -= wret; 144 } 145 continue; 146 } 147 if (errno == EWOULDBLOCK) { 148 struct tty_delay *td; 149 struct timeval to; 150 151 if (tty_delayed >= TTYMAXDELAY) { 152 log_warnx("tty device \"%s\": %s", 153 device, "too many delayed writes"); 154 break; 155 } 156 log_debug("ttymsg delayed write"); 157 if (iov != localiov) { 158 memmove(localiov, iov, 159 iovcnt * sizeof(struct iovec)); 160 iov = localiov; 161 } 162 if ((td = malloc(sizeof(*td))) == NULL) { 163 log_warn("allocate delay tty device \"%s\"", 164 device); 165 break; 166 } 167 td->td_length = 0; 168 if (left > LOG_MAXLINE) 169 left = LOG_MAXLINE; 170 while (iovcnt && left) { 171 if (iov->iov_len > left) 172 iov->iov_len = left; 173 memcpy(td->td_line + td->td_length, 174 iov->iov_base, iov->iov_len); 175 td->td_length += iov->iov_len; 176 left -= iov->iov_len; 177 ++iov; 178 --iovcnt; 179 } 180 tty_delayed++; 181 event_set(&td->td_event, fd, EV_WRITE, ttycb, td); 182 to.tv_sec = TTYMSGTIME; 183 to.tv_usec = 0; 184 event_add(&td->td_event, &to); 185 return; 186 } 187 /* 188 * We get ENODEV on a slip line if we're running as root, 189 * and EIO if the line just went away. 190 */ 191 if (errno != ENODEV && errno != EIO) 192 log_warn("writev tty device \"%s\"", device); 193 break; 194 } 195 196 (void) close(fd); 197 return; 198 } 199 200 void 201 ttycb(int fd, short event, void *arg) 202 { 203 struct tty_delay *td = arg; 204 struct timeval to; 205 ssize_t wret; 206 207 if (event != EV_WRITE) 208 goto done; 209 210 wret = write(fd, td->td_line, td->td_length); 211 if (wret == -1 && errno != EINTR && errno != EWOULDBLOCK) 212 goto done; 213 if (wret > 0) { 214 td->td_length -= wret; 215 if (td->td_length == 0) 216 goto done; 217 memmove(td->td_line, td->td_line + wret, td->td_length); 218 } 219 to.tv_sec = TTYMSGTIME; 220 to.tv_usec = 0; 221 event_add(&td->td_event, &to); 222 return; 223 224 done: 225 tty_delayed--; 226 close(fd); 227 free(td); 228 } 229