xref: /csrg-svn/libexec/rlogind/rlogind.c (revision 11345)
1 #ifndef lint
2 static char sccsid[] = "@(#)rlogind.c	4.12 83/02/28";
3 #endif
4 
5 #include <stdio.h>
6 #include <sys/types.h>
7 #include <sys/stat.h>
8 #include <sys/socket.h>
9 
10 #include <netinet/in.h>
11 
12 #include <errno.h>
13 #include <pwd.h>
14 #include <wait.h>
15 #include <signal.h>
16 #include <sgtty.h>
17 #include <stdio.h>
18 #include <netdb.h>
19 
20 extern	errno;
21 int	reapchild();
22 struct	passwd *getpwnam();
23 char	*crypt(), *rindex(), *index(), *malloc(), *ntoa();
24 struct	sockaddr_in sin = { AF_INET };
25 /*
26  * remote login server:
27  *	remuser\0
28  *	locuser\0
29  *	terminal type\0
30  *	data
31  */
32 main(argc, argv)
33 	int argc;
34 	char **argv;
35 {
36 	int f, options = SO_KEEPALIVE;
37 	struct sockaddr_in from;
38 	struct servent *sp;
39 
40 	sp = getservbyname("login", "tcp");
41 	if (sp == 0) {
42 		fprintf(stderr, "rlogind: tcp/rlogin: unknown service\n");
43 		exit(1);
44 	}
45 #ifndef DEBUG
46 	if (fork())
47 		exit(0);
48 	for (f = 0; f < 10; f++)
49 		(void) close(f);
50 	(void) open("/", 0);
51 	(void) dup2(0, 1);
52 	(void) dup2(0, 2);
53 	{ int tt = open("/dev/tty", 2);
54 	  if (tt > 0) {
55 		ioctl(tt, TIOCNOTTY, 0);
56 		close(tt);
57 	  }
58 	}
59 #endif
60 	sin.sin_port = sp->s_port;
61 	argc--, argv++;
62 	if (argc > 0 && !strcmp(argv[0], "-d")) {
63 		options |= SO_DEBUG;
64 		argc--, argv++;
65 	}
66 	if (argc > 0) {
67 		int port = atoi(argv[0]);
68 
69 		if (port < 0) {
70 			fprintf(stderr, "%s: bad port #\n", argv[0]);
71 			exit(1);
72 		}
73 		sin.sin_port = htons((u_short)port);
74 		argv++, argc--;
75 	}
76 	f = socket(AF_INET, SOCK_STREAM, 0, 0);
77 	if (f < 0) {
78 		perror("rlogind: socket");
79 		exit(1);
80 	}
81 	if (options & SO_DEBUG)
82 		if (setsockopt(f, SOL_SOCKET, SO_DEBUG, 0, 0) < 0)
83 			perror("rlogind: setsockopt (SO_DEBUG)");
84 #ifdef notdef
85 	if (setsockopt(f, SOL_SOCKET, SO_KEEPALIVE, 0, 0) < 0)
86 		perror("rlogind: setsocktopt (SO_KEEPALIVE)");
87 #endif
88 	if (bind(f, &sin, sizeof (sin), 0) < 0) {
89 		perror("rlogind: bind");
90 		exit(1);
91 	}
92 	sigset(SIGCHLD, reapchild);
93 	listen(f, 10);
94 	for (;;) {
95 		int s, len = sizeof (from);
96 
97 		s = accept(f, &from, &len, 0);
98 		if (s < 0) {
99 			if (errno == EINTR)
100 				continue;
101 			perror("rlogind: accept");
102 			continue;
103 		}
104 		if (fork() == 0) {
105 			signal(SIGCHLD, SIG_IGN);
106 			doit(s, &from);
107 		}
108 		close(s);
109 	}
110 }
111 
112 reapchild()
113 {
114 	union wait status;
115 
116 	while (wait3(&status, WNOHANG, 0) > 0)
117 		;
118 }
119 
120 char	locuser[32], remuser[32];
121 char	buf[BUFSIZ];
122 int	child;
123 int	cleanup();
124 int	netf;
125 extern	errno;
126 char	*line;
127 
128 doit(f, fromp)
129 	int f;
130 	struct sockaddr_in *fromp;
131 {
132 	char c;
133 	int i, p, cc, t, pid;
134 	int stop = TIOCPKT_DOSTOP;
135 	register struct hostent *hp;
136 
137 	alarm(60);
138 	read(f, &c, 1);
139 	if (c != 0)
140 		exit(1);
141 	alarm(0);
142 	fromp->sin_port = htons((u_short)fromp->sin_port);
143 	hp = gethostbyaddr(&fromp->sin_addr, sizeof (struct in_addr),
144 		fromp->sin_family);
145 	if (hp == 0) {
146 		char buf[BUFSIZ], *cp = (char *)&fromp->sin_addr;
147 
148 		fatal(f, sprintf(buf, "Host name for your address (%s) unknown",
149 			ntoa(fromp->sin_addr)));
150 	}
151 	if (fromp->sin_family != AF_INET ||
152 	    fromp->sin_port >= IPPORT_RESERVED ||
153 	    hp == 0)
154 		fatal(f, "Permission denied");
155 	write(f, "", 1);
156 	for (c = 'p'; c <= 's'; c++) {
157 		struct stat stb;
158 		line = "/dev/ptyXX";
159 		line[strlen("/dev/pty")] = c;
160 		line[strlen("/dev/ptyp")] = '0';
161 		if (stat(line, &stb) < 0)
162 			break;
163 		for (i = 0; i < 16; i++) {
164 			line[strlen("/dev/ptyp")] = "0123456789abcdef"[i];
165 			p = open(line, 2);
166 			if (p > 0)
167 				goto gotpty;
168 		}
169 	}
170 	fatal(f, "All network ports in use");
171 	/*NOTREACHED*/
172 gotpty:
173 	dup2(f, 0);
174 	line[strlen("/dev/")] = 't';
175 #ifdef DEBUG
176 	{ int tt = open("/dev/tty", 2);
177 	  if (tt > 0) {
178 		ioctl(tt, TIOCNOTTY, 0);
179 		close(tt);
180 	  }
181 	}
182 #endif
183 	t = open(line, 2);
184 	if (t < 0)
185 		fatalperror(f, line, errno);
186 	{ struct sgttyb b;
187 	  gtty(t, &b); b.sg_flags = RAW|ANYP; stty(t, &b);
188 	}
189 	pid = fork();
190 	if (pid < 0)
191 		fatalperror(f, "", errno);
192 	if (pid) {
193 		char pibuf[1024], fibuf[1024], *pbp, *fbp;
194 		int pcc = 0, fcc = 0, on = 1;
195 /* FILE *console = fopen("/dev/console", "w");  */
196 /* setbuf(console, 0); */
197 
198 /* fprintf(console, "f %d p %d\r\n", f, p); */
199 		ioctl(f, FIONBIO, &on);
200 		ioctl(p, FIONBIO, &on);
201 		ioctl(p, TIOCPKT, &on);
202 		signal(SIGTSTP, SIG_IGN);
203 		sigset(SIGCHLD, cleanup);
204 		for (;;) {
205 			int ibits = 0, obits = 0;
206 
207 			if (fcc)
208 				obits |= (1<<p);
209 			else
210 				ibits |= (1<<f);
211 			if (pcc >= 0)
212 				if (pcc)
213 					obits |= (1<<f);
214 				else
215 					ibits |= (1<<p);
216 			if (fcc < 0 && pcc < 0)
217 				break;
218 /* fprintf(console, "ibits from %d obits from %d\r\n", ibits, obits); */
219 			select(16, &ibits, &obits, 0, 0, 0);
220 /* fprintf(console, "ibits %d obits %d\r\n", ibits, obits); */
221 			if (ibits == 0 && obits == 0) {
222 				sleep(5);
223 				continue;
224 			}
225 			if (ibits & (1<<f)) {
226 				fcc = read(f, fibuf, sizeof (fibuf));
227 /* fprintf(console, "%d from f\r\n", fcc); */
228 				if (fcc < 0 && errno == EWOULDBLOCK)
229 					fcc = 0;
230 				else {
231 					if (fcc <= 0)
232 						break;
233 					fbp = fibuf;
234 				}
235 			}
236 			if (ibits & (1<<p)) {
237 				pcc = read(p, pibuf, sizeof (pibuf));
238 /* fprintf(console, "%d from p, buf[0] %x, errno %d\r\n", pcc, buf[0], errno); */
239 				pbp = pibuf;
240 				if (pcc < 0 && errno == EWOULDBLOCK)
241 					pcc = 0;
242 				else if (pcc <= 0)
243 					pcc = -1;
244 				else if (pibuf[0] == 0)
245 					pbp++, pcc--;
246 				else {
247 					if (pibuf[0]&(TIOCPKT_FLUSHWRITE|
248 						      TIOCPKT_NOSTOP|
249 						      TIOCPKT_DOSTOP)) {
250 						int nstop = pibuf[0] &
251 						    (TIOCPKT_NOSTOP|
252 						     TIOCPKT_DOSTOP);
253 						if (nstop)
254 							stop = nstop;
255 						pibuf[0] |= nstop;
256 						send(f,&pibuf[0],1,SOF_OOB);
257 					}
258 					pcc = 0;
259 				}
260 			}
261 			if ((obits & (1<<f)) && pcc > 0) {
262 				cc = write(f, pbp, pcc);
263 /* fprintf(console, "%d of %d to f\r\n", cc, pcc); */
264 				if (cc > 0) {
265 					pcc -= cc;
266 					pbp += cc;
267 				}
268 			}
269 			if ((obits & (1<<p)) && fcc > 0) {
270 				cc = write(p, fbp, fcc);
271 /* fprintf(console, "%d of %d to p\r\n", cc, fcc); */
272 				if (cc > 0) {
273 					fcc -= cc;
274 					fbp += cc;
275 				}
276 			}
277 		}
278 		cleanup();
279 	}
280 	close(f);
281 	close(p);
282 	dup2(t, 0);
283 	dup2(t, 1);
284 	dup2(t, 2);
285 	close(t);
286 	execl("/bin/login", "login", "-r", hp->h_name, 0);
287 	fatalperror(2, "/bin/login", errno);
288 	/*NOTREACHED*/
289 }
290 
291 cleanup()
292 {
293 
294 	rmut();
295 	vhangup();		/* XXX */
296 	shutdown(netf, 2);
297 	kill(0, SIGKILL);
298 	exit(1);
299 }
300 
301 fatal(f, msg)
302 	int f;
303 	char *msg;
304 {
305 	char buf[BUFSIZ];
306 
307 	buf[0] = '\01';		/* error indicator */
308 	(void) sprintf(buf + 1, "rlogind: %s.\n", msg);
309 	(void) write(f, buf, strlen(buf));
310 	exit(1);
311 }
312 
313 fatalperror(f, msg, errno)
314 	int f;
315 	char *msg;
316 	int errno;
317 {
318 	char buf[BUFSIZ];
319 	extern char *sys_errlist[];
320 
321 	(void) sprintf(buf, "%s: %s", msg, sys_errlist[errno]);
322 	fatal(f, buf);
323 }
324 
325 #include <utmp.h>
326 
327 struct	utmp wtmp;
328 char	wtmpf[]	= "/usr/adm/wtmp";
329 char	utmp[] = "/etc/utmp";
330 #define SCPYN(a, b)	strncpy(a, b, sizeof(a))
331 #define SCMPN(a, b)	strncmp(a, b, sizeof(a))
332 
333 rmut()
334 {
335 	register f;
336 	int found = 0;
337 
338 	f = open(utmp, 2);
339 	if (f >= 0) {
340 		while(read(f, (char *)&wtmp, sizeof(wtmp)) == sizeof(wtmp)) {
341 			if (SCMPN(wtmp.ut_line, line+5) || wtmp.ut_name[0]==0)
342 				continue;
343 			lseek(f, -(long)sizeof(wtmp), 1);
344 			SCPYN(wtmp.ut_name, "");
345 			time(&wtmp.ut_time);
346 			write(f, (char *)&wtmp, sizeof(wtmp));
347 			found++;
348 		}
349 		close(f);
350 	}
351 	if (found) {
352 		f = open(wtmpf, 1);
353 		if (f >= 0) {
354 			SCPYN(wtmp.ut_line, line+5);
355 			SCPYN(wtmp.ut_name, "");
356 			time(&wtmp.ut_time);
357 			lseek(f, (long)0, 2);
358 			write(f, (char *)&wtmp, sizeof(wtmp));
359 			close(f);
360 		}
361 	}
362 	chmod(line, 0666);
363 	chown(line, 0, 0);
364 	line[strlen("/dev/")] = 'p';
365 	chmod(line, 0666);
366 	chown(line, 0, 0);
367 }
368 
369 /*
370  * Convert network-format internet address
371  * to base 256 d.d.d.d representation.
372  */
373 char *
374 ntoa(in)
375 	struct in_addr in;
376 {
377 	static char b[18];
378 	register char *p;
379 
380 	p = (char *)&in;
381 #define	UC(b)	(((int)b)&0xff)
382 	sprintf(b, "%d.%d.%d.%d", UC(p[0]), UC(p[1]), UC(p[2]), UC(p[3]));
383 	return (b);
384 }
385