1 /* $OpenBSD: ttymsg.c,v 1.11 2016/08/16 18:41:57 tedu 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 35 #include <dirent.h> 36 #include <errno.h> 37 #include <event.h> 38 #include <paths.h> 39 #include <signal.h> 40 #include <stdio.h> 41 #include <stdlib.h> 42 #include <string.h> 43 #include <unistd.h> 44 45 #include "syslogd.h" 46 47 #ifndef nitems 48 #define nitems(_a) (sizeof((_a)) / sizeof((_a)[0])) 49 #endif 50 51 struct tty_delay { 52 struct event td_event; 53 size_t td_length; 54 char td_line[MAXLINE]; 55 }; 56 int tty_delayed = 0; 57 void ttycb(int, short, void *); 58 59 /* 60 * Display the contents of a uio structure on a terminal. 61 * Schedules an event if write would block, waiting up to TTYMSGTIME 62 * seconds. Returns pointer to error string on unexpected error; 63 * string is not newline-terminated. Various "normal" errors are ignored 64 * (exclusive-use, lack of permission, etc.). 65 */ 66 char * 67 ttymsg(struct iovec *iov, int iovcnt, char *utline) 68 { 69 static char device[MAXNAMLEN] = _PATH_DEV; 70 static char ebuf[ERRBUFSIZE]; 71 int cnt, fd; 72 size_t left; 73 ssize_t wret; 74 struct iovec localiov[6]; 75 76 if (iovcnt < 0 || (size_t)iovcnt > nitems(localiov)) 77 return ("too many iov's (change code in syslogd/ttymsg.c)"); 78 79 /* 80 * Ignore lines that start with "ftp" or "uucp". 81 */ 82 if ((strncmp(utline, "ftp", 3) == 0) || 83 (strncmp(utline, "uucp", 4) == 0)) 84 return (NULL); 85 86 (void) strlcpy(device + sizeof(_PATH_DEV) - 1, utline, 87 sizeof(device) - (sizeof(_PATH_DEV) - 1)); 88 if (strchr(device + sizeof(_PATH_DEV) - 1, '/')) { 89 /* A slash is an attempt to break security... */ 90 (void) snprintf(ebuf, sizeof(ebuf), "'/' in \"%s\"", 91 device); 92 return (ebuf); 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 return (NULL); 102 (void) snprintf(ebuf, sizeof(ebuf), 103 "%s: %s", device, strerror(errno)); 104 return (ebuf); 105 } 106 107 left = 0; 108 for (cnt = 0; cnt < iovcnt; ++cnt) 109 left += iov[cnt].iov_len; 110 111 for (;;) { 112 wret = writev(fd, iov, iovcnt); 113 if (wret >= 0) { 114 if ((size_t)wret >= left) 115 break; 116 left -= wret; 117 if (iov != localiov) { 118 bcopy(iov, localiov, 119 iovcnt * sizeof(struct iovec)); 120 iov = localiov; 121 } 122 while ((size_t)wret >= iov->iov_len) { 123 wret -= iov->iov_len; 124 ++iov; 125 --iovcnt; 126 } 127 if (wret) { 128 iov->iov_base = (char *)iov->iov_base + wret; 129 iov->iov_len -= wret; 130 } 131 continue; 132 } 133 if (errno == EWOULDBLOCK) { 134 struct tty_delay *td; 135 struct timeval to; 136 137 if (tty_delayed >= TTYMAXDELAY) { 138 (void) snprintf(ebuf, sizeof(ebuf), 139 "%s: too many delayed writes", device); 140 return (ebuf); 141 } 142 logdebug("ttymsg delayed write\n"); 143 if (iov != localiov) { 144 bcopy(iov, localiov, 145 iovcnt * sizeof(struct iovec)); 146 iov = localiov; 147 } 148 if ((td = malloc(sizeof(*td))) == NULL) { 149 (void) snprintf(ebuf, sizeof(ebuf), 150 "%s: malloc: %s", device, strerror(errno)); 151 return (ebuf); 152 } 153 td->td_length = 0; 154 if (left > MAXLINE) 155 left = MAXLINE; 156 while (iovcnt && left) { 157 if (iov->iov_len > left) 158 iov->iov_len = left; 159 memcpy(td->td_line + td->td_length, 160 iov->iov_base, iov->iov_len); 161 td->td_length += iov->iov_len; 162 left -= iov->iov_len; 163 ++iov; 164 --iovcnt; 165 } 166 tty_delayed++; 167 event_set(&td->td_event, fd, EV_WRITE, ttycb, td); 168 to.tv_sec = TTYMSGTIME; 169 to.tv_usec = 0; 170 event_add(&td->td_event, &to); 171 return (NULL); 172 } 173 /* 174 * We get ENODEV on a slip line if we're running as root, 175 * and EIO if the line just went away. 176 */ 177 if (errno == ENODEV || errno == EIO) 178 break; 179 (void) close(fd); 180 (void) snprintf(ebuf, sizeof(ebuf), 181 "%s: %s", device, strerror(errno)); 182 return (ebuf); 183 } 184 185 (void) close(fd); 186 return (NULL); 187 } 188 189 void 190 ttycb(int fd, short event, void *arg) 191 { 192 struct tty_delay *td = arg; 193 struct timeval to; 194 ssize_t wret; 195 196 if (event != EV_WRITE) 197 goto done; 198 199 wret = write(fd, td->td_line, td->td_length); 200 if (wret < 0 && errno != EINTR && errno != EWOULDBLOCK) 201 goto done; 202 if (wret > 0) { 203 td->td_length -= wret; 204 if (td->td_length == 0) 205 goto done; 206 memmove(td->td_line, td->td_line + wret, td->td_length); 207 } 208 to.tv_sec = TTYMSGTIME; 209 to.tv_usec = 0; 210 event_add(&td->td_event, &to); 211 return; 212 213 done: 214 tty_delayed--; 215 close(fd); 216 free(td); 217 } 218