Annotation of src/usr.bin/wall/ttymsg.c, Revision 1.1
1.1 ! deraadt 1: /* $NetBSD: ttymsg.c,v 1.3 1994/11/17 07:17:55 jtc Exp $ */
! 2:
! 3: /*
! 4: * Copyright (c) 1989, 1993
! 5: * The Regents of the University of California. All rights reserved.
! 6: *
! 7: * Redistribution and use in source and binary forms, with or without
! 8: * modification, are permitted provided that the following conditions
! 9: * are met:
! 10: * 1. Redistributions of source code must retain the above copyright
! 11: * notice, this list of conditions and the following disclaimer.
! 12: * 2. Redistributions in binary form must reproduce the above copyright
! 13: * notice, this list of conditions and the following disclaimer in the
! 14: * documentation and/or other materials provided with the distribution.
! 15: * 3. All advertising materials mentioning features or use of this software
! 16: * must display the following acknowledgement:
! 17: * This product includes software developed by the University of
! 18: * California, Berkeley and its contributors.
! 19: * 4. Neither the name of the University nor the names of its contributors
! 20: * may be used to endorse or promote products derived from this software
! 21: * without specific prior written permission.
! 22: *
! 23: * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
! 24: * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
! 25: * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
! 26: * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
! 27: * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
! 28: * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
! 29: * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
! 30: * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
! 31: * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
! 32: * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
! 33: * SUCH DAMAGE.
! 34: */
! 35:
! 36: #ifndef lint
! 37: #if 0
! 38: static char sccsid[] = "@(#)ttymsg.c 8.2 (Berkeley) 11/16/93";
! 39: #endif
! 40: static char rcsid[] = "$NetBSD: ttymsg.c,v 1.3 1994/11/17 07:17:55 jtc Exp $";
! 41: #endif /* not lint */
! 42:
! 43: #include <sys/types.h>
! 44: #include <sys/uio.h>
! 45: #include <signal.h>
! 46: #include <fcntl.h>
! 47: #include <dirent.h>
! 48: #include <errno.h>
! 49: #include <paths.h>
! 50: #include <unistd.h>
! 51: #include <stdio.h>
! 52: #include <string.h>
! 53: #include <stdlib.h>
! 54:
! 55: /*
! 56: * Display the contents of a uio structure on a terminal. Used by wall(1),
! 57: * syslogd(8), and talkd(8). Forks and finishes in child if write would block,
! 58: * waiting up to tmout seconds. Returns pointer to error string on unexpected
! 59: * error; string is not newline-terminated. Various "normal" errors are
! 60: * ignored (exclusive-use, lack of permission, etc.).
! 61: */
! 62: char *
! 63: ttymsg(iov, iovcnt, line, tmout)
! 64: struct iovec *iov;
! 65: int iovcnt;
! 66: char *line;
! 67: int tmout;
! 68: {
! 69: static char device[MAXNAMLEN] = _PATH_DEV;
! 70: static char errbuf[1024];
! 71: register int cnt, fd, left, wret;
! 72: struct iovec localiov[6];
! 73: int forked = 0;
! 74:
! 75: if (iovcnt > sizeof(localiov) / sizeof(localiov[0]))
! 76: return ("too many iov's (change code in wall/ttymsg.c)");
! 77:
! 78: (void) strcpy(device + sizeof(_PATH_DEV) - 1, line);
! 79: if (strchr(device + sizeof(_PATH_DEV) - 1, '/')) {
! 80: /* A slash is an attempt to break security... */
! 81: (void) snprintf(errbuf, sizeof(errbuf), "'/' in \"%s\"",
! 82: device);
! 83: return (errbuf);
! 84: }
! 85:
! 86: /*
! 87: * open will fail on slip lines or exclusive-use lines
! 88: * if not running as root; not an error.
! 89: */
! 90: if ((fd = open(device, O_WRONLY|O_NONBLOCK, 0)) < 0) {
! 91: if (errno == EBUSY || errno == EACCES)
! 92: return (NULL);
! 93: (void) snprintf(errbuf, sizeof(errbuf),
! 94: "%s: %s", device, strerror(errno));
! 95: return (errbuf);
! 96: }
! 97:
! 98: for (cnt = left = 0; cnt < iovcnt; ++cnt)
! 99: left += iov[cnt].iov_len;
! 100:
! 101: for (;;) {
! 102: wret = writev(fd, iov, iovcnt);
! 103: if (wret >= left)
! 104: break;
! 105: if (wret >= 0) {
! 106: left -= wret;
! 107: if (iov != localiov) {
! 108: bcopy(iov, localiov,
! 109: iovcnt * sizeof(struct iovec));
! 110: iov = localiov;
! 111: }
! 112: for (cnt = 0; wret >= iov->iov_len; ++cnt) {
! 113: wret -= iov->iov_len;
! 114: ++iov;
! 115: --iovcnt;
! 116: }
! 117: if (wret) {
! 118: iov->iov_base += wret;
! 119: iov->iov_len -= wret;
! 120: }
! 121: continue;
! 122: }
! 123: if (errno == EWOULDBLOCK) {
! 124: int cpid, off = 0;
! 125:
! 126: if (forked) {
! 127: (void) close(fd);
! 128: _exit(1);
! 129: }
! 130: cpid = fork();
! 131: if (cpid < 0) {
! 132: (void) snprintf(errbuf, sizeof(errbuf),
! 133: "fork: %s", strerror(errno));
! 134: (void) close(fd);
! 135: return (errbuf);
! 136: }
! 137: if (cpid) { /* parent */
! 138: (void) close(fd);
! 139: return (NULL);
! 140: }
! 141: forked++;
! 142: /* wait at most tmout seconds */
! 143: (void) signal(SIGALRM, SIG_DFL);
! 144: (void) signal(SIGTERM, SIG_DFL); /* XXX */
! 145: (void) sigsetmask(0);
! 146: (void) alarm((u_int)tmout);
! 147: (void) fcntl(fd, O_NONBLOCK, &off);
! 148: continue;
! 149: }
! 150: /*
! 151: * We get ENODEV on a slip line if we're running as root,
! 152: * and EIO if the line just went away.
! 153: */
! 154: if (errno == ENODEV || errno == EIO)
! 155: break;
! 156: (void) close(fd);
! 157: if (forked)
! 158: _exit(1);
! 159: (void) snprintf(errbuf, sizeof(errbuf),
! 160: "%s: %s", device, strerror(errno));
! 161: return (errbuf);
! 162: }
! 163:
! 164: (void) close(fd);
! 165: if (forked)
! 166: _exit(0);
! 167: return (NULL);
! 168: }
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