| /* |
| * 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. All advertising materials mentioning features or use of this software |
| * must display the following acknowledgement: |
| * This product includes software developed by the University of |
| * California, Berkeley and its contributors. |
| * 4. 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. |
| * |
| * Modified Sun Mar 12 10:39:22 1995, faith@cs.unc.edu for Linux |
| * |
| */ |
| |
| #ifndef lint |
| static char sccsid[] = "@(#)ttymsg.c 8.2 (Berkeley) 11/16/93"; |
| #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> |
| |
| #ifdef __linux__ |
| #include "pathnames.h" |
| #endif |
| |
| /* |
| * Display the contents of a uio structure on a terminal. Used by wall(1), |
| * syslogd(8), 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]; |
| static char errbuf[1024]; |
| register int cnt, fd, left, wret; |
| struct iovec localiov[6]; |
| int forked = 0; |
| |
| if (iovcnt > sizeof(localiov) / sizeof(localiov[0])) |
| return ("too many iov's (change code in wall/ttymsg.c)"); |
| |
| if (strchr(line, '/')) { |
| /* A slash is an attempt to break security... */ |
| (void) snprintf(errbuf, sizeof(errbuf), "'/' in \"%s\"", |
| device); |
| return (errbuf); |
| } |
| (void) snprintf(device, sizeof(device), "%s%s", _PATH_DEV, line); |
| |
| /* |
| * 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) { |
| iov->iov_base += wret; |
| iov->iov_len -= wret; |
| } |
| continue; |
| } |
| if (errno == EWOULDBLOCK) { |
| int cpid, off = 0; |
| |
| 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) sigsetmask(0); |
| (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); |
| } |