1 /* $OpenBSD: ttymsg.c,v 1.16 2017/08/08 14:23:23 bluhm 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/stat.h> 34 #include <sys/syslog.h> 35 36 #include <dirent.h> 37 #include <errno.h> 38 #include <event.h> 39 #include <paths.h> 40 #include <signal.h> 41 #include <stdio.h> 42 #include <stdlib.h> 43 #include <string.h> 44 #include <unistd.h> 45 46 #include "log.h" 47 #include "syslogd.h" 48 49 #ifndef nitems 50 #define nitems(_a) (sizeof((_a)) / sizeof((_a)[0])) 51 #endif 52 53 struct tty_delay { 54 struct event td_event; 55 size_t td_length; 56 char td_line[LOG_MAXLINE]; 57 }; 58 int tty_delayed = 0; 59 void ttycb(int, short, void *); 60 61 /* 62 * Display the contents of a uio structure on a terminal. 63 * Schedules an event if write would block, waiting up to TTYMSGTIME 64 * seconds. 65 */ 66 void 67 ttymsg(struct iovec *iov, int iovcnt, char *utline) 68 { 69 static char device[MAXNAMLEN] = _PATH_DEV; 70 int cnt, fd; 71 size_t left; 72 ssize_t wret; 73 struct iovec localiov[6]; 74 75 if (iovcnt < 0 || (size_t)iovcnt > nitems(localiov)) { 76 log_warnx("too many iov's (change code in syslogd/ttymsg.c)"); 77 return; 78 } 79 80 /* 81 * Ignore lines that start with "ftp" or "uucp". 82 */ 83 if ((strncmp(utline, "ftp", 3) == 0) || 84 (strncmp(utline, "uucp", 4) == 0)) 85 return; 86 87 (void) strlcpy(device + sizeof(_PATH_DEV) - 1, utline, 88 sizeof(device) - (sizeof(_PATH_DEV) - 1)); 89 if (strchr(device + sizeof(_PATH_DEV) - 1, '/')) { 90 /* A slash is an attempt to break security... */ 91 log_warnx("'/' in tty device \"%s\"", device); 92 return; 93 } 94 95 /* 96 * open will fail on slip lines or exclusive-use lines 97 * if not running as root; not an error. 98 */ 99 if ((fd = priv_open_tty(device)) < 0) { 100 if (errno != EBUSY && errno != EACCES) 101 log_warn("priv_open_tty device \"%s\"", device); 102 return; 103 } 104 105 left = 0; 106 for (cnt = 0; cnt < iovcnt; ++cnt) 107 left += iov[cnt].iov_len; 108 109 for (;;) { 110 wret = writev(fd, iov, iovcnt); 111 if (wret >= 0) { 112 if ((size_t)wret >= left) 113 break; 114 left -= wret; 115 if (iov != localiov) { 116 memmove(localiov, iov, 117 iovcnt * sizeof(struct iovec)); 118 iov = localiov; 119 } 120 while ((size_t)wret >= iov->iov_len) { 121 wret -= iov->iov_len; 122 ++iov; 123 --iovcnt; 124 } 125 if (wret) { 126 iov->iov_base = (char *)iov->iov_base + wret; 127 iov->iov_len -= wret; 128 } 129 continue; 130 } 131 if (errno == EWOULDBLOCK) { 132 struct tty_delay *td; 133 struct timeval to; 134 135 if (tty_delayed >= TTYMAXDELAY) { 136 log_warnx("tty device \"%s\": %s", 137 device, "too many delayed writes"); 138 break; 139 } 140 log_debug("ttymsg delayed write"); 141 if (iov != localiov) { 142 memmove(localiov, iov, 143 iovcnt * sizeof(struct iovec)); 144 iov = localiov; 145 } 146 if ((td = malloc(sizeof(*td))) == NULL) { 147 log_warn("allocate delay tty device \"%s\"", 148 device); 149 break; 150 } 151 td->td_length = 0; 152 if (left > LOG_MAXLINE) 153 left = LOG_MAXLINE; 154 while (iovcnt && left) { 155 if (iov->iov_len > left) 156 iov->iov_len = left; 157 memcpy(td->td_line + td->td_length, 158 iov->iov_base, iov->iov_len); 159 td->td_length += iov->iov_len; 160 left -= iov->iov_len; 161 ++iov; 162 --iovcnt; 163 } 164 tty_delayed++; 165 event_set(&td->td_event, fd, EV_WRITE, ttycb, td); 166 to.tv_sec = TTYMSGTIME; 167 to.tv_usec = 0; 168 event_add(&td->td_event, &to); 169 return; 170 } 171 /* 172 * We get ENODEV on a slip line if we're running as root, 173 * and EIO if the line just went away. 174 */ 175 if (errno != ENODEV && errno != EIO) 176 log_warn("writev tty device \"%s\"", device); 177 break; 178 } 179 180 (void) close(fd); 181 return; 182 } 183 184 void 185 ttycb(int fd, short event, void *arg) 186 { 187 struct tty_delay *td = arg; 188 struct timeval to; 189 ssize_t wret; 190 191 if (event != EV_WRITE) 192 goto done; 193 194 wret = write(fd, td->td_line, td->td_length); 195 if (wret < 0 && errno != EINTR && errno != EWOULDBLOCK) 196 goto done; 197 if (wret > 0) { 198 td->td_length -= wret; 199 if (td->td_length == 0) 200 goto done; 201 memmove(td->td_line, td->td_line + wret, td->td_length); 202 } 203 to.tv_sec = TTYMSGTIME; 204 to.tv_usec = 0; 205 event_add(&td->td_event, &to); 206 return; 207 208 done: 209 tty_delayed--; 210 close(fd); 211 free(td); 212 } 213