/* $NetBSD: rlogin.c,v 1.46 2020/05/03 16:11:06 christos Exp $ */
/*
* Copyright (c) 1983, 1990, 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.
*/
#include <sys/cdefs.h>
#ifndef lint
__COPYRIGHT("@(#) Copyright (c) 1983, 1990, 1993\
The Regents of the University of California. All rights reserved.");
#endif /* not lint */
#ifndef lint
#if 0
static char sccsid[] = "@(#)rlogin.c 8.4 (Berkeley) 4/29/95";
#else
__RCSID("$NetBSD: rlogin.c,v 1.46 2020/05/03 16:11:06 christos Exp $");
#endif
#endif /* not lint */
/*
* rlogin - remote login
*/
#include <sys/param.h>
#include <sys/ioctl.h>
#include <sys/socket.h>
#include <sys/time.h>
#include <sys/resource.h>
#include <sys/wait.h>
#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/ip.h>
#include <netinet/tcp.h>
#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <netdb.h>
#include <pwd.h>
#include <setjmp.h>
#include <signal.h>
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <termios.h>
#include <unistd.h>
#include "getport.h"
#ifndef TIOCPKT_WINDOW
#define TIOCPKT_WINDOW 0x80
#endif
/* concession to Sun */
#ifndef SIGUSR1
#define SIGUSR1 30
#endif
#ifndef CCEQ
#define CCEQ(val, c) (c == val ? val != _POSIX_VDISABLE : 0)
#endif
static int eight, rem;
static struct termios deftty;
static int noescape;
static u_char escapechar = '~';
#ifdef OLDSUN
struct winsize {
unsigned short ws_row, ws_col;
unsigned short ws_xpixel, ws_ypixel;
};
#else
#define get_window_size(fd, wp) ioctl(fd, TIOCGWINSZ, wp)
#endif
static struct winsize winsize;
static void catch_child(int);
static void copytochild(int);
__dead static void doit(sigset_t *);
__dead static void done(int);
static void echo(int);
static u_int getescape(char *);
__dead static void lostpeer(int);
static void mode(int);
static void msg(const char *);
static void oob(int);
static int reader(sigset_t *);
static void sendwindow(void);
static void setsignal(int);
static void sigwinch(int);
static void stop(int);
__dead static void usage(void);
static void writer(void);
static void writeroob(int);
#ifdef OLDSUN
static int get_window_size(int, struct winsize *);
#endif
int
main(int argc, char *argv[])
{
struct passwd *pw;
struct servent *sp;
struct termios tty;
sigset_t imask, omask;
uid_t uid;
int argoff, ch, dflag, nflag, one;
int i, len, len2;
int family = AF_UNSPEC;
char *host, *p, *user, *name, term[1024] = "network";
speed_t ospeed;
struct sigaction sa;
char *service = NULL;
struct rlimit rlim;
argoff = dflag = nflag = 0;
one = 1;
host = user = NULL;
sp = NULL;
if (strcmp(getprogname(), "rlogin") != 0) {
host = strdup(getprogname());
if (host == NULL)
err(1, NULL);
}
/* handle "rlogin host flags" */
if (!host && argc > 2 && argv[1][0] != '-') {
host = argv[1];
argoff = 1;
}
#define OPTIONS "468dEe:l:np:"
while ((ch = getopt(argc - argoff, argv + argoff, OPTIONS)) != -1)
switch(ch) {
case '4':
family = AF_INET;
break;
case '6':
family = AF_INET6;
break;
case '8':
eight = 1;
break;
case 'd':
dflag = 1;
break;
case 'E':
noescape = 1;
break;
case 'e':
noescape = 0;
escapechar = getescape(optarg);
break;
case 'l':
user = optarg;
break;
case 'n':
nflag = 1;
break;
case 'p':
sp = getport(service = optarg, "tcp");
break;
case '?':
default:
usage();
}
optind += argoff;
argc -= optind;
argv += optind;
/* if haven't gotten a host yet, do so */
if (!host && !(host = *argv++))
usage();
if (*argv)
usage();
if (!(pw = getpwuid(uid = getuid())))
errx(1, "unknown user id.");
/* Accept user1@host format, though "-l user2" overrides user1 */
p = strchr(host, '@');
if (p) {
*p = '\0';
if (!user && p > host)
user = host;
host = p + 1;
if (*host == '\0')
usage();
}
if ((name = strdup(pw->pw_name)) == NULL)
err(1, "malloc");
if (!user)
user = name;
if (sp == NULL)
sp = getservbyname("login", "tcp");
if (sp == NULL)
errx(1, "login/tcp: unknown service.");
if ((p = getenv("TERM")) != NULL)
(void)strlcpy(term, p, sizeof(term));
len = strlen(term);
if (len < (int)(sizeof(term) - 1) && tcgetattr(0, &tty) == 0) {
/* start at 2 to include the / */
for (ospeed = i = cfgetospeed(&tty), len2 = 2; i > 9; len2++)
i /= 10;
if (len + len2 < (int)sizeof(term))
(void)snprintf(term + len, len2 + 1, "/%d", ospeed);
}
(void)get_window_size(0, &winsize);
sigemptyset(&sa.sa_mask);
sa.sa_flags = SA_RESTART;
sa.sa_handler = lostpeer;
(void)sigaction(SIGPIPE, &sa, NULL);
/* will use SIGUSR1 for window size hack, so hold it off */
sigemptyset(&imask);
sigaddset(&imask, SIGURG);
sigaddset(&imask, SIGUSR1);
(void)sigprocmask(SIG_SETMASK, &imask, &omask);
/*
* We set SIGURG and SIGUSR1 below so that an
* incoming signal will be held pending rather than being
* discarded. Note that these routines will be ready to get
* a signal by the time that they are unblocked below.
*/
sa.sa_handler = copytochild;
(void)sigaction(SIGURG, &sa, NULL);
sa.sa_handler = writeroob;
(void)sigaction(SIGUSR1, &sa, NULL);
/* don't dump core */
rlim.rlim_cur = rlim.rlim_max = 0;
if (setrlimit(RLIMIT_CORE, &rlim) < 0)
warn("setrlimit");
rem = rcmd_af(&host, sp->s_port, name, user, term, 0, family);
if (rem < 0)
exit(1);
if (dflag &&
setsockopt(rem, SOL_SOCKET, SO_DEBUG, &one, sizeof(one)) < 0)
warn("setsockopt DEBUG (ignored)");
if (nflag &&
setsockopt(rem, IPPROTO_TCP, TCP_NODELAY, &one, sizeof(one)) < 0)
warn("setsockopt NODELAY (ignored)");
{
struct sockaddr_storage ss;
socklen_t sslen = sizeof(ss);
if (getsockname(rem, (struct sockaddr *)&ss, &sslen) == 0
&& ((struct sockaddr *)&ss)->sa_family == AF_INET) {
one = IPTOS_LOWDELAY;
if (setsockopt(rem, IPPROTO_IP, IP_TOS, (char *)&one,
sizeof(int)) < 0)
warn("setsockopt TOS (ignored)");
}
}
(void)setuid(uid);
doit(&omask);
/*NOTREACHED*/
return (0);
}
static pid_t child;
static void
doit(sigset_t *smask)
{
struct sigaction sa;
sigemptyset(&sa.sa_mask);
sa.sa_flags = SA_RESTART;
sa.sa_handler = SIG_IGN;
(void)sigaction(SIGINT, &sa, NULL);
setsignal(SIGHUP);
setsignal(SIGQUIT);
mode(1);
child = fork();
if (child == -1) {
warn("fork");
done(1);
}
if (child == 0) {
mode(1);
if (reader(smask) == 0) {
msg("connection closed.");
exit(0);
}
sleep(1);
msg("\aconnection closed.");
exit(1);
}
/*
* We may still own the socket, and may have a pending SIGURG (or might
* receive one soon) that we really want to send to the reader. When
* one of these comes in, the trap copytochild simply copies such
* signals to the child. We can now unblock SIGURG and SIGUSR1
* that were set above.
*/
(void)sigprocmask(SIG_SETMASK, smask, NULL);
sa.sa_handler = catch_child;
(void)sigaction(SIGCHLD, &sa, NULL);
writer();
msg("closed connection.");
done(0);
}
/* trap a signal, unless it is being ignored. */
static void
setsignal(int sig)
{
struct sigaction isa, osa;
sigset_t isigs, osigs;
sigemptyset(&isigs);
sigaddset(&isigs, sig);
sigprocmask(SIG_BLOCK, &isigs, &osigs);
sigemptyset(&isa.sa_mask);
isa.sa_handler = exit;
isa.sa_flags = SA_RESTART;
(void)sigaction(sig, &isa, &osa);
if (osa.sa_handler == SIG_IGN)
(void)sigaction(sig, &osa, NULL);
(void)sigprocmask(SIG_SETMASK, &osigs, NULL);
}
static void
done(int status)
{
pid_t w;
int wstatus;
struct sigaction sa;
mode(0);
if (child > 0) {
/* make sure catch_child does not snap it up */
sigemptyset(&sa.sa_mask);
sa.sa_handler = SIG_DFL;
sa.sa_flags = 0;
(void)sigaction(SIGCHLD, &sa, NULL);
if (kill(child, SIGKILL) >= 0)
while ((w = wait(&wstatus)) > 0 && w != child)
continue;
}
exit(status);
}
static int dosigwinch;
/*
* This is called when the reader process gets the out-of-band (urgent)
* request to turn on the window-changing protocol.
*/
static void
writeroob(int signo)
{
struct sigaction sa;
if (dosigwinch == 0) {
sendwindow();
sigemptyset(&sa.sa_mask);
sa.sa_handler = sigwinch;
sa.sa_flags = SA_RESTART;
(void)sigaction(SIGWINCH, &sa, NULL);
}
dosigwinch = 1;
}
static void
catch_child(int signo)
{
int status;
pid_t pid;
for (;;) {
pid = waitpid(-1, &status, WNOHANG|WUNTRACED);
if (pid == 0)
return;
/* if the child (reader) dies, just quit */
if (pid < 0 || (pid == child && !WIFSTOPPED(status)))
done(WEXITSTATUS(status) | WTERMSIG(status));
}
/* NOTREACHED */
}
/*
* writer: write to remote: 0 -> line.
* ~. terminate
* ~^Z suspend rlogin process.
* ~<delayed-suspend char> suspend rlogin process, but leave reader alone.
*/
static void
writer(void)
{
int bol, local;
ssize_t n;
char c;
bol = 1; /* beginning of line */
local = 0;
for (;;) {
n = read(STDIN_FILENO, &c, 1);
if (n <= 0) {
if (n < 0 && errno == EINTR)
continue;
break;
}
/*
* If we're at the beginning of the line and recognize a
* command character, then we echo locally. Otherwise,
* characters are echo'd remotely. If the command character
* is doubled, this acts as a force and local echo is
* suppressed.
*/
if (bol) {
bol = 0;
if (!noescape && c == escapechar) {
local = 1;
continue;
}
} else if (local) {
local = 0;
if (c == '.' || CCEQ(deftty.c_cc[VEOF], c)) {
echo((int)c);
break;
}
if (CCEQ(deftty.c_cc[VSUSP], c)) {
bol = 1;
echo((int)c);
stop(1);
continue;
}
if (CCEQ(deftty.c_cc[VDSUSP], c)) {
bol = 1;
echo((int)c);
stop(0);
continue;
}
if (c != escapechar) {
(void)write(rem, &escapechar, 1);
}
}
if (write(rem, &c, 1) == 0) {
msg("line gone");
break;
}
bol = CCEQ(deftty.c_cc[VKILL], c) ||
CCEQ(deftty.c_cc[VEOF], c) ||
CCEQ(deftty.c_cc[VINTR], c) ||
CCEQ(deftty.c_cc[VSUSP], c) ||
c == '\r' || c == '\n';
}
}
static void
echo(int i)
{
char c = (char)i;
char *p;
char buf[8];
p = buf;
c &= 0177;
*p++ = escapechar;
if (c < ' ') {
*p++ = '^';
*p++ = c + '@';
} else if (c == 0177) {
*p++ = '^';
*p++ = '?';
} else
*p++ = c;
*p++ = '\r';
*p++ = '\n';
(void)write(STDOUT_FILENO, buf, p - buf);
}
static void
stop(int all)
{
struct sigaction sa;
mode(0);
sigemptyset(&sa.sa_mask);
sa.sa_handler = SIG_IGN;
sa.sa_flags = SA_RESTART;
(void)sigaction(SIGCHLD, &sa, NULL);
(void)kill(all ? 0 : getpid(), SIGTSTP);
sa.sa_handler = catch_child;
(void)sigaction(SIGCHLD, &sa, NULL);
mode(1);
sigwinch(0); /* check for size changes */
}
static void
sigwinch(int signo)
{
struct winsize ws;
if (dosigwinch && get_window_size(0, &ws) == 0 &&
memcmp(&ws, &winsize, sizeof(ws))) {
winsize = ws;
sendwindow();
}
}
/*
* Send the window size to the server via the magic escape
*/
static void
sendwindow(void)
{
struct winsize *wp;
char obuf[4 + sizeof (struct winsize)];
wp = (struct winsize *)(obuf+4);
obuf[0] = 0377;
obuf[1] = 0377;
obuf[2] = 's';
obuf[3] = 's';
wp->ws_row = htons(winsize.ws_row);
wp->ws_col = htons(winsize.ws_col);
wp->ws_xpixel = htons(winsize.ws_xpixel);
wp->ws_ypixel = htons(winsize.ws_ypixel);
(void)write(rem, obuf, sizeof(obuf));
}
/*
* reader: read from remote: line -> 1
*/
#define READING 1
#define WRITING 2
static jmp_buf rcvtop;
static pid_t ppid;
static ssize_t rcvcnt, rcvstate;
static char rcvbuf[8 * 1024];
static void
oob(int signo)
{
struct termios tty;
int atmark;
ssize_t n, rcvd;
char waste[BUFSIZ], mark;
rcvd = 0;
while (recv(rem, &mark, 1, MSG_OOB) == -1) {
switch (errno) {
case EWOULDBLOCK:
/*
* Urgent data not here yet. It may not be possible
* to send it yet if we are blocked for output and
* our input buffer is full.
*/
if (rcvcnt < (ssize_t)sizeof(rcvbuf)) {
n = read(rem, rcvbuf + rcvcnt,
sizeof(rcvbuf) - rcvcnt);
if (n <= 0)
return;
rcvd += n;
} else {
n = read(rem, waste, sizeof(waste));
if (n <= 0)
return;
}
continue;
default:
return;
}
}
if (mark & TIOCPKT_WINDOW) {
/* Let server know about window size changes */
(void)kill(ppid, SIGUSR1);
}
if (!eight && (mark & TIOCPKT_NOSTOP)) {
(void)tcgetattr(0, &tty);
tty.c_iflag &= ~IXON;
(void)tcsetattr(0, TCSANOW, &tty);
}
if (!eight && (mark & TIOCPKT_DOSTOP)) {
(void)tcgetattr(0, &tty);
tty.c_iflag |= (deftty.c_iflag & IXON);
(void)tcsetattr(0, TCSANOW, &tty);
}
if (mark & TIOCPKT_FLUSHWRITE) {
(void)tcflush(1, TCIOFLUSH);
for (;;) {
if (ioctl(rem, SIOCATMARK, &atmark) < 0) {
warn("ioctl SIOCATMARK (ignored)");
break;
}
if (atmark)
break;
n = read(rem, waste, sizeof (waste));
if (n <= 0)
break;
}
/*
* Don't want any pending data to be output, so clear the recv
* buffer. If we were hanging on a write when interrupted,
* don't want it to restart. If we were reading, restart
* anyway.
*/
rcvcnt = 0;
longjmp(rcvtop, 1);
}
/* oob does not do FLUSHREAD (alas!) */
/*
* If we filled the receive buffer while a read was pending, longjmp
* to the top to restart appropriately. Don't abort a pending write,
* however, or we won't know how much was written.
*/
if (rcvd && rcvstate == READING)
longjmp(rcvtop, 1);
}
/* reader: read from remote: line -> 1 */
static int
reader(sigset_t *smask)
{
pid_t pid;
ssize_t n, remaining;
char *bufp;
struct sigaction sa;
pid = getpid(); /* modern systems use positives for pid */
sigemptyset(&sa.sa_mask);
sa.sa_flags = SA_RESTART;
sa.sa_handler = SIG_IGN;
(void)sigaction(SIGTTOU, &sa, NULL);
sa.sa_handler = oob;
(void)sigaction(SIGURG, &sa, NULL);
ppid = getppid();
(void)fcntl(rem, F_SETOWN, pid);
(void)setjmp(rcvtop);
(void)sigprocmask(SIG_SETMASK, smask, NULL);
bufp = rcvbuf;
for (;;) {
while ((remaining = rcvcnt - (bufp - rcvbuf)) > 0) {
rcvstate = WRITING;
n = write(STDOUT_FILENO, bufp, remaining);
if (n < 0) {
if (errno != EINTR)
return (-1);
continue;
}
bufp += n;
}
bufp = rcvbuf;
rcvcnt = 0;
rcvstate = READING;
rcvcnt = read(rem, rcvbuf, sizeof (rcvbuf));
if (rcvcnt == 0)
return (0);
if (rcvcnt < 0) {
if (errno == EINTR)
continue;
warn("read");
return (-1);
}
}
}
static void
mode(int f)
{
struct termios tty;
switch (f) {
case 0:
(void)tcsetattr(0, TCSANOW, &deftty);
break;
case 1:
(void)tcgetattr(0, &deftty);
tty = deftty;
/* This is loosely derived from sys/compat/tty_compat.c. */
tty.c_lflag &= ~(ECHO|ICANON|ISIG|IEXTEN);
tty.c_iflag &= ~ICRNL;
tty.c_oflag &= ~OPOST;
tty.c_cc[VMIN] = 1;
tty.c_cc[VTIME] = 0;
if (eight) {
tty.c_iflag &= IXOFF;
tty.c_cflag &= ~(CSIZE|PARENB);
tty.c_cflag |= CS8;
}
(void)tcsetattr(0, TCSANOW, &tty);
break;
default:
return;
}
}
static void
lostpeer(int signo)
{
struct sigaction sa;
sa.sa_flags = SA_RESTART;
sa.sa_handler = SIG_IGN;
sigemptyset(&sa.sa_mask);
(void)sigaction(SIGPIPE, &sa, NULL);
msg("\aconnection closed.");
done(1);
}
/* copy SIGURGs to the child process. */
static void
copytochild(int signo)
{
(void)kill(child, SIGURG);
}
static void
msg(const char *str)
{
(void)fprintf(stderr, "rlogin: %s\r\n", str);
}
static void
usage(void)
{
(void)fprintf(stderr,
"Usage: %s [-468dEn] [-e char] [-l username] [-p port] "
"[username@]host\n", getprogname());
exit(1);
}
/*
* The following routine provides compatibility (such as it is) between older
* Suns and others. Suns have only a `ttysize', so we convert it to a winsize.
*/
#ifdef OLDSUN
static int
get_window_size(int fd, struct winsize *wp)
{
struct ttysize ts;
int error;
if ((error = ioctl(0, TIOCGSIZE, &ts)) != 0)
return (error);
wp->ws_row = ts.ts_lines;
wp->ws_col = ts.ts_cols;
wp->ws_xpixel = 0;
wp->ws_ypixel = 0;
return (0);
}
#endif
static u_int
getescape(char *p)
{
long val;
size_t len;
if ((len = strlen(p)) == 1) /* use any single char, including '\' */
return ((u_int)*p);
/* otherwise, \nnn */
if (*p == '\\' && len >= 2 && len <= 4) {
val = strtol(++p, NULL, 8);
for (;;) {
if (!*++p)
return ((u_int)val);
if (*p < '0' || *p > '8')
break;
}
}
msg("illegal option value -- e");
usage();
/* NOTREACHED */
return (0);
}
![[BACK]](/icons/back.gif){kind=icon}
Return to rlogin.c CVS log ![[TXT]](/icons/text.gif){kind=icon}
![[DIR]](/icons/dir.gif){kind=icon}
Up to [cvs.NetBSD.org] / src / usr.bin / rlogin