/netkit-ntalk-0.17/talkd/announce.c
C | 219 lines | 135 code | 14 blank | 70 comment | 25 complexity | 6ed3d6452c51123124765269313c4830 MD5 | raw file
- /*
- * Copyright (c) 1983 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.
- */
- /*
- * From: @(#)announce.c 5.9 (Berkeley) 2/26/91
- */
- char ann_rcsid[] =
- "$Id: announce.c,v 1.8 2000/07/22 15:27:39 dholland Exp $";
- #include <sys/types.h>
- #include <sys/stat.h>
- #include <sys/time.h>
- #include <time.h>
- #include <sys/wait.h>
- #include <sys/socket.h>
- #include <errno.h>
- #include <syslog.h>
- #include <unistd.h>
- #include <stdio.h>
- #include <fcntl.h>
- #include <string.h>
- #include <paths.h>
- #include "prot_talkd.h"
- #include "proto.h"
- /*
- * Announce an invitation to talk.
- *
- * Because the tty driver insists on attaching a terminal-less
- * process to any terminal that it writes on, we must fork a child
- * to protect ourselves.
- *
- * That hasn't been true since, hrm, 4.2BSD maybe? Even in System V,
- * we can use O_NOCTTY. On the other hand, forking is a good idea in
- * case the tty hangs. But at present we don't take advantage of that;
- * we'd wait() forever.
- */
- /*
- * Reject control codes and other crap.
- * FUTURE: don't clear high ascii if the tty is in 8-bit mode
- * Note that we don't need to let through tabs or newlines here.
- */
- static int safechar(int ch) {
- if (ch>127 || ch<32) ch = '?';
- return ch;
- }
- #define max(a,b) ( (a) > (b) ? (a) : (b) )
- #define N_LINES 5
- #define N_CHARS 120
- /*
- * Build a block of characters containing the message.
- * It is sent blank filled and in a single block to
- * try to keep the message in one piece if the recipient
- * is in, say, vi at the time.
- */
- static void
- print_mesg(int fd, CTL_MSG *request, const char *remote_machine)
- {
- struct timeval clocc;
- struct timezone zone;
- struct tm *localclock;
- char line_buf[N_LINES][N_CHARS];
- int sizes[N_LINES];
- char big_buf[N_LINES*(N_CHARS+2)+16];
- char *bptr, *lptr;
- int i, j, max_size;
- time_t footime;
- i = 0;
- max_size = 0;
- gettimeofday(&clocc, &zone);
- footime = clocc.tv_sec;
- localclock = localtime(&footime);
- snprintf(line_buf[i], N_CHARS, " ");
- sizes[i] = strlen(line_buf[i]);
- max_size = max(max_size, sizes[i]);
- i++;
- snprintf(line_buf[i], N_CHARS,
- "Message from Talk_Daemon@%s at %d:%02d ...",
- ourhostname, localclock->tm_hour, localclock->tm_min);
- sizes[i] = strlen(line_buf[i]);
- max_size = max(max_size, sizes[i]);
- i++;
- snprintf(line_buf[i], N_CHARS, "talk: connection requested by %s@%s.",
- request->l_name, remote_machine);
- sizes[i] = strlen(line_buf[i]);
- max_size = max(max_size, sizes[i]);
- i++;
- if (strpbrk(request->l_name, ":!.") != NULL)
- snprintf(line_buf[i], N_CHARS, "talk: respond with: talk %s@%s -x",
- request->l_name, remote_machine);
- else
- snprintf(line_buf[i], N_CHARS, "talk: respond with: talk %s@%s",
- request->l_name, remote_machine);
- sizes[i] = strlen(line_buf[i]);
- max_size = max(max_size, sizes[i]);
- i++;
- snprintf(line_buf[i], N_CHARS, " ");
- sizes[i] = strlen(line_buf[i]);
- max_size = max(max_size, sizes[i]);
- i++;
- bptr = big_buf;
- *bptr++ = ''; /* send something to wake them up */
- *bptr++ = '\r'; /* add a \r in case of raw mode */
- *bptr++ = '\n';
- for (i = 0; i < N_LINES; i++) {
- /* copy the line into the big buffer */
- lptr = line_buf[i];
- while (*lptr != '\0')
- *(bptr++) = safechar(*(lptr++));
- /* pad out the rest of the lines with blanks */
- for (j = sizes[i]; j < max_size + 2; j++)
- *(bptr++) = ' ';
- *(bptr++) = '\r'; /* add a \r in case of raw mode */
- *(bptr++) = '\n';
- }
- *bptr = 0;
- write(fd, big_buf, strlen(big_buf));
- }
- /*
- * See if the user is accepting messages. If so, announce that
- * a talk is requested.
- */
- static int
- announce_proc(CTL_MSG *request, const char *remote_machine)
- {
- char full_tty[32];
- int fd;
- struct stat stbuf;
- snprintf(full_tty, sizeof(full_tty), "%s/%s", _PATH_DEV,
- request->r_tty);
- if (access(full_tty, F_OK) != 0)
- return FAILED;
- fd = open(full_tty, O_WRONLY|O_NOCTTY);
- if (fd<0) {
- return (PERMISSION_DENIED);
- }
- if (fstat(fd, &stbuf) < 0) {
- return (PERMISSION_DENIED);
- }
- if ((stbuf.st_mode&020) == 0) {
- return (PERMISSION_DENIED);
- }
- print_mesg(fd, request, remote_machine);
- close(fd);
- return SUCCESS;
- }
- int
- announce(CTL_MSG *request, const char *remote_machine)
- {
- int pid, val, status;
- pid = fork();
- if (pid==-1) {
- /* fork failed */
- return FAILED;
- }
- if (pid==0) {
- /* child */
- status = announce_proc(request, remote_machine);
- _exit(status);
- }
- /* we are the parent, so wait for the child */
- do {
- val = wait(&status);
- if (val == -1) {
- if (errno == EINTR || errno == EAGAIN)
- continue;
- /* shouldn't happen */
- syslog(LOG_WARNING, "announce: wait: %m");
- return (FAILED);
- }
- } while (val != pid);
- if (WIFSIGNALED(status)) {
- /* we were killed by some signal */
- return FAILED;
- }
- /* Send back the exit/return code */
- return (WEXITSTATUS(status));
- }