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/* $OpenBSD: ttylog.c,v 1.8 2021/07/06 11:50:34 bluhm Exp $ */
/*
* Copyright (c) 2015 Alexander Bluhm <bluhm@openbsd.org>
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
#include <sys/ioctl.h>
#include <sys/sockio.h>
#include <errno.h>
#include <err.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <signal.h>
#include <string.h>
#include <termios.h>
#include <time.h>
#include <unistd.h>
#include <util.h>
#include <utmp.h>
__dead void usage(void);
void redirect(void);
void restore(void);
void timeout(int);
void terminate(int);
void iostdin(int);
FILE *lg;
char ptyname[16], *console, *username, *logfile, *tty;
int mfd, sfd;
__dead void
usage()
{
fprintf(stderr, "usage: %s /dev/console|username logfile\n",
getprogname());
exit(2);
}
int
main(int argc, char *argv[])
{
char buf[8192];
struct sigaction act;
sigset_t set;
ssize_t n;
if (argc != 3)
usage();
if (strcmp(argv[1], "/dev/console") == 0)
console = argv[1];
else
username = argv[1];
logfile = argv[2];
sigemptyset(&set);
sigaddset(&set, SIGTERM);
sigaddset(&set, SIGIO);
if (sigprocmask(SIG_BLOCK, &set, NULL) == -1)
err(1, "sigprocmask block init");
if ((lg = fopen(logfile, "w")) == NULL)
err(1, "fopen %s", logfile);
if (setvbuf(lg, NULL, _IOLBF, 0) != 0)
err(1, "setlinebuf");
memset(&act, 0, sizeof(act));
act.sa_mask = set;
act.sa_flags = SA_RESTART;
act.sa_handler = terminate;
if (sigaction(SIGTERM, &act, NULL) == -1)
err(1, "sigaction SIGTERM");
if (sigaction(SIGINT, &act, NULL) == -1)
err(1, "sigaction SIGINT");
if (openpty(&mfd, &sfd, ptyname, NULL, NULL) == -1)
err(1, "openpty");
fprintf(lg, "openpty %s\n", ptyname);
if ((tty = strrchr(ptyname, '/')) == NULL)
errx(1, "tty: %s", ptyname);
tty++;
/* login(3) searches for a controlling tty, use the created one */
if (dup2(sfd, 1) == -1)
err(1, "dup2 stdout");
redirect();
act.sa_handler = iostdin;
if (sigaction(SIGIO, &act, NULL) == -1)
err(1, "sigaction SIGIO");
if (setpgid(0, 0) == -1)
err(1, "setpgid");
if (fcntl(0, F_SETOWN, getpid()) == -1)
err(1, "fcntl F_SETOWN");
if (fcntl(0, F_SETFL, O_ASYNC) == -1)
err(1, "fcntl O_ASYNC");
act.sa_handler = timeout;
if (sigaction(SIGALRM, &act, NULL) == -1)
err(1, "sigaction SIGALRM");
alarm(30);
fprintf(lg, "%s: started\n", getprogname());
if (sigprocmask(SIG_UNBLOCK, &set, NULL) == -1)
err(1, "sigprocmask unblock init");
/* do not block signals during read, it has to be interrupted */
while ((n = read(mfd, buf, sizeof(buf))) > 0) {
if (sigprocmask(SIG_BLOCK, &set, NULL) == -1)
err(1, "sigprocmask block write");
fprintf(lg, ">>> ");
if (fwrite(buf, 1, n, lg) != (size_t)n)
err(1, "fwrite %s", logfile);
if (buf[n-1] != '\n')
fprintf(lg, "\n");
if (sigprocmask(SIG_UNBLOCK, &set, NULL) == -1)
err(1, "sigprocmask unblock write");
}
if (sigprocmask(SIG_BLOCK, &set, NULL) == -1)
err(1, "sigprocmask block exit");
if (n < 0)
err(1, "read %s", ptyname);
fprintf(lg, "EOF %s\n", ptyname);
restore();
errx(3, "EOF");
}
void
redirect(void)
{
struct utmp utmp;
int fd, on;
if (console) {
/* first remove any existing console redirection */
on = 0;
if ((fd = open("/dev/console", O_WRONLY)) == -1)
err(1, "open /dev/console");
if (ioctl(fd, TIOCCONS, &on) == -1)
err(1, "ioctl TIOCCONS");
close(fd);
/* then redirect console to our pseudo tty */
on = 1;
if (ioctl(sfd, TIOCCONS, &on) == -1)
err(1, "ioctl TIOCCONS on");
fprintf(lg, "console %s on %s\n", console, tty);
}
if (username) {
memset(&utmp, 0, sizeof(utmp));
strlcpy(utmp.ut_line, tty, sizeof(utmp.ut_line));
strlcpy(utmp.ut_name, username, sizeof(utmp.ut_name));
time(&utmp.ut_time);
login(&utmp);
fprintf(lg, "login %s %s\n", username, tty);
}
}
void
restore(void)
{
int on;
if (tty == NULL)
return;
if (console) {
on = 0;
if (ioctl(sfd, TIOCCONS, &on) == -1)
err(1, "ioctl TIOCCONS off");
fprintf(lg, "console %s off\n", tty);
}
if (username) {
if (logout(tty) == 0)
errx(1, "logout %s", tty);
fprintf(lg, "logout %s\n", tty);
}
}
void
timeout(int sig)
{
fprintf(lg, "signal timeout %d\n", sig);
restore();
errx(3, "timeout");
}
void
terminate(int sig)
{
fprintf(lg, "signal terminate %d\n", sig);
restore();
errx(3, "terminate");
}
void
iostdin(int sig)
{
char buf[8192];
ssize_t n;
fprintf(lg, "signal iostdin %d\n", sig);
/* try to read as many log messages as possible before terminating */
if (fcntl(mfd, F_SETFL, O_NONBLOCK) == -1)
err(1, "fcntl O_NONBLOCK");
while ((n = read(mfd, buf, sizeof(buf))) > 0) {
fprintf(lg, ">>> ");
if (fwrite(buf, 1, n, lg) != (size_t)n)
err(1, "fwrite %s", logfile);
if (buf[n-1] != '\n')
fprintf(lg, "\n");
}
if (n < 0 && errno != EAGAIN)
err(1, "read %s", ptyname);
if ((n = read(0, buf, sizeof(buf))) < 0)
err(1, "read stdin");
restore();
if (n > 0)
errx(3, "read stdin %zd bytes", n);
exit(0);
}
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