1 /* $OpenBSD: ttymsg.c,v 1.10 2016/04/02 19:55:10 krw 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 <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 "syslogd.h" 47 48 struct tty_delay { 49 struct event td_event; 50 size_t td_length; 51 char td_line[MAXLINE]; 52 }; 53 int tty_delayed = 0; 54 void ttycb(int, short, void *); 55 56 /* 57 * Display the contents of a uio structure on a terminal. 58 * Schedules an event if write would block, waiting up to TTYMSGTIME 59 * seconds. Returns pointer to error string on unexpected error; 60 * string is not newline-terminated. Various "normal" errors are ignored 61 * (exclusive-use, lack of permission, etc.). 62 */ 63 char * 64 ttymsg(struct iovec *iov, int iovcnt, char *utline) 65 { 66 static char device[MAXNAMLEN] = _PATH_DEV; 67 static char ebuf[ERRBUFSIZE]; 68 int cnt, fd; 69 size_t left; 70 ssize_t wret; 71 struct iovec localiov[6]; 72 73 if (iovcnt < 0 || (size_t)iovcnt > nitems(localiov)) 74 return ("too many iov's (change code in syslogd/ttymsg.c)"); 75 76 /* 77 * Ignore lines that start with "ftp" or "uucp". 78 */ 79 if ((strncmp(utline, "ftp", 3) == 0) || 80 (strncmp(utline, "uucp", 4) == 0)) 81 return (NULL); 82 83 (void) strlcpy(device + sizeof(_PATH_DEV) - 1, utline, 84 sizeof(device) - (sizeof(_PATH_DEV) - 1)); 85 if (strchr(device + sizeof(_PATH_DEV) - 1, '/')) { 86 /* A slash is an attempt to break security... */ 87 (void) snprintf(ebuf, sizeof(ebuf), "'/' in \"%s\"", 88 device); 89 return (ebuf); 90 } 91 92 /* 93 * open will fail on slip lines or exclusive-use lines 94 * if not running as root; not an error. 95 */ 96 if ((fd = priv_open_tty(device)) < 0) { 97 if (errno == EBUSY || errno == EACCES) 98 return (NULL); 99 (void) snprintf(ebuf, sizeof(ebuf), 100 "%s: %s", device, strerror(errno)); 101 return (ebuf); 102 } 103 104 left = 0; 105 for (cnt = 0; cnt < iovcnt; ++cnt) 106 left += iov[cnt].iov_len; 107 108 for (;;) { 109 wret = writev(fd, iov, iovcnt); 110 if (wret >= 0) { 111 if ((size_t)wret >= left) 112 break; 113 left -= wret; 114 if (iov != localiov) { 115 bcopy(iov, localiov, 116 iovcnt * sizeof(struct iovec)); 117 iov = localiov; 118 } 119 while ((size_t)wret >= iov->iov_len) { 120 wret -= iov->iov_len; 121 ++iov; 122 --iovcnt; 123 } 124 if (wret) { 125 iov->iov_base = (char *)iov->iov_base + wret; 126 iov->iov_len -= wret; 127 } 128 continue; 129 } 130 if (errno == EWOULDBLOCK) { 131 struct tty_delay *td; 132 struct timeval to; 133 134 if (tty_delayed >= TTYMAXDELAY) { 135 (void) snprintf(ebuf, sizeof(ebuf), 136 "%s: too many delayed writes", device); 137 return (ebuf); 138 } 139 logdebug("ttymsg delayed write\n"); 140 if (iov != localiov) { 141 bcopy(iov, localiov, 142 iovcnt * sizeof(struct iovec)); 143 iov = localiov; 144 } 145 if ((td = malloc(sizeof(*td))) == NULL) { 146 (void) snprintf(ebuf, sizeof(ebuf), 147 "%s: malloc: %s", device, strerror(errno)); 148 return (ebuf); 149 } 150 td->td_length = 0; 151 if (left > MAXLINE) 152 left = MAXLINE; 153 while (iovcnt && left) { 154 if (iov->iov_len > left) 155 iov->iov_len = left; 156 memcpy(td->td_line + td->td_length, 157 iov->iov_base, iov->iov_len); 158 td->td_length += iov->iov_len; 159 left -= iov->iov_len; 160 ++iov; 161 --iovcnt; 162 } 163 tty_delayed++; 164 event_set(&td->td_event, fd, EV_WRITE, ttycb, td); 165 to.tv_sec = TTYMSGTIME; 166 to.tv_usec = 0; 167 event_add(&td->td_event, &to); 168 return (NULL); 169 } 170 /* 171 * We get ENODEV on a slip line if we're running as root, 172 * and EIO if the line just went away. 173 */ 174 if (errno == ENODEV || errno == EIO) 175 break; 176 (void) close(fd); 177 (void) snprintf(ebuf, sizeof(ebuf), 178 "%s: %s", device, strerror(errno)); 179 return (ebuf); 180 } 181 182 (void) close(fd); 183 return (NULL); 184 } 185 186 void 187 ttycb(int fd, short event, void *arg) 188 { 189 struct tty_delay *td = arg; 190 struct timeval to; 191 ssize_t wret; 192 193 if (event != EV_WRITE) 194 goto done; 195 196 wret = write(fd, td->td_line, td->td_length); 197 if (wret < 0 && errno != EINTR && errno != EWOULDBLOCK) 198 goto done; 199 if (wret > 0) { 200 td->td_length -= wret; 201 if (td->td_length == 0) 202 goto done; 203 memmove(td->td_line, td->td_line + wret, td->td_length); 204 } 205 to.tv_sec = TTYMSGTIME; 206 to.tv_usec = 0; 207 event_add(&td->td_event, &to); 208 return; 209 210 done: 211 tty_delayed--; 212 close(fd); 213 free(td); 214 } 215