/* $OpenBSD: ttymsg.c,v 1.15 2004/09/14 23:01:31 deraadt Exp $ */ /* $NetBSD: ttymsg.c,v 1.3 1994/11/17 07:17:55 jtc Exp $ */ /* * Copyright (c) 1989, 1993 * The Regents of the University of California. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. */ #ifndef lint #if 0 static const char sccsid[] = "@(#)ttymsg.c 8.2 (Berkeley) 11/16/93"; #endif static const char rcsid[] = "$OpenBSD: ttymsg.c,v 1.15 2004/09/14 23:01:31 deraadt Exp $"; #endif /* not lint */ #include <sys/types.h> #include <sys/uio.h> #include <signal.h> #include <fcntl.h> #include <dirent.h> #include <errno.h> #include <paths.h> #include <unistd.h> #include <stdio.h> #include <string.h> #include <stdlib.h> #include <sys/stat.h> char *ttymsg(struct iovec *, int, char *, int); /* * Display the contents of a uio structure on a terminal. Used by wall(1) * and talkd(8). Forks and finishes in child if write would block, * waiting up to tmout seconds. Returns pointer to error string on unexpected * error; string is not newline-terminated. Various "normal" errors are * ignored (exclusive-use, lack of permission, etc.). */ char * ttymsg(iov, iovcnt, line, tmout) struct iovec *iov; int iovcnt; char *line; int tmout; { static char device[MAXNAMLEN] = _PATH_DEV; static char errbuf[1024]; int cnt, fd, left, wret; struct iovec localiov[6]; int forked = 0; struct stat st; sigset_t mask; if (iovcnt > sizeof(localiov) / sizeof(localiov[0])) return ("too many iov's (change code in wall/ttymsg.c)"); /* * Ignore lines that start with "ftp" or "uucp". */ if ((strncmp(line, "ftp", 3) == 0) || (strncmp(line, "uucp", 4) == 0)) return (NULL); (void) strlcpy(device + sizeof(_PATH_DEV) - 1, line, sizeof(device) - (sizeof(_PATH_DEV) - 1)); if (strchr(device + sizeof(_PATH_DEV) - 1, '/')) { /* A slash is an attempt to break security... */ (void) snprintf(errbuf, sizeof(errbuf), "'/' in \"%s\"", device); return (errbuf); } if (getuid()) { if (stat(device, &st) < 0) return (NULL); if ((st.st_mode & S_IWGRP) == 0) return (NULL); } /* * open will fail on slip lines or exclusive-use lines * if not running as root; not an error. */ if ((fd = open(device, O_WRONLY|O_NONBLOCK, 0)) < 0) { if (errno == EBUSY || errno == EACCES) return (NULL); (void) snprintf(errbuf, sizeof(errbuf), "%s: %s", device, strerror(errno)); return (errbuf); } for (cnt = left = 0; cnt < iovcnt; ++cnt) left += iov[cnt].iov_len; for (;;) { wret = writev(fd, iov, iovcnt); if (wret >= left) break; if (wret >= 0) { left -= wret; if (iov != localiov) { bcopy(iov, localiov, iovcnt * sizeof(struct iovec)); iov = localiov; } for (cnt = 0; wret >= iov->iov_len; ++cnt) { wret -= iov->iov_len; ++iov; --iovcnt; } if (wret) { char *base = iov->iov_base; iov->iov_base = base + wret; iov->iov_len -= wret; } continue; } if (errno == EWOULDBLOCK) { int off = 0; pid_t cpid; if (forked) { (void) close(fd); _exit(1); } cpid = fork(); if (cpid < 0) { (void) snprintf(errbuf, sizeof(errbuf), "fork: %s", strerror(errno)); (void) close(fd); return (errbuf); } if (cpid) { /* parent */ (void) close(fd); return (NULL); } forked++; /* wait at most tmout seconds */ (void) signal(SIGALRM, SIG_DFL); (void) signal(SIGTERM, SIG_DFL); /* XXX */ (void) sigemptyset(&mask); (void) sigprocmask(SIG_SETMASK, &mask, NULL); (void) alarm((u_int)tmout); (void) fcntl(fd, O_NONBLOCK, &off); continue; } /* * We get ENODEV on a slip line if we're running as root, * and EIO if the line just went away. */ if (errno == ENODEV || errno == EIO) break; (void) close(fd); if (forked) _exit(1); (void) snprintf(errbuf, sizeof(errbuf), "%s: %s", device, strerror(errno)); return (errbuf); } (void) close(fd); if (forked) _exit(0); return (NULL); }