xref: /csrg-svn/libexec/rlogind/rlogind.c (revision 10585)
1 #ifndef lint
2 static char sccsid[] = "@(#)rlogind.c	4.10 83/01/22";
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();
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 			doit(s, &from);
106 		close(s);
107 	}
108 }
109 
110 reapchild()
111 {
112 	union wait status;
113 
114 	while (wait3(&status, WNOHANG, 0) > 0)
115 		;
116 }
117 
118 char	locuser[32], remuser[32];
119 char	buf[BUFSIZ];
120 int	child;
121 int	cleanup();
122 int	netf;
123 extern	errno;
124 char	*line;
125 
126 doit(f, fromp)
127 	int f;
128 	struct sockaddr_in *fromp;
129 {
130 	char c;
131 	int i, p, cc, t, pid;
132 	int stop = TIOCPKT_DOSTOP;
133 	register struct hostent *hp;
134 
135 	alarm(60);
136 	read(f, &c, 1);
137 	if (c != 0)
138 		exit(1);
139 	alarm(0);
140 	fromp->sin_port = htons((u_short)fromp->sin_port);
141 	hp = gethostbyaddr(&fromp->sin_addr, sizeof (struct in_addr),
142 		fromp->sin_family);
143 	if (hp == 0)
144 		fatal(f, "Host name for your address unknown");
145 	if (fromp->sin_family != AF_INET ||
146 	    fromp->sin_port >= IPPORT_RESERVED ||
147 	    hp == 0)
148 		fatal(f, "Permission denied");
149 	write(f, "", 1);
150 	for (c = 'p'; c <= 's'; c++) {
151 		struct stat stb;
152 		line = "/dev/ptyXX";
153 		line[strlen("/dev/pty")] = c;
154 		line[strlen("/dev/ptyp")] = '0';
155 		if (stat(line, &stb) < 0)
156 			break;
157 		for (i = 0; i < 16; i++) {
158 			line[strlen("/dev/ptyp")] = "0123456789abcdef"[i];
159 			p = open(line, 2);
160 			if (p > 0)
161 				goto gotpty;
162 		}
163 	}
164 	fatal(f, "All network ports in use");
165 	/*NOTREACHED*/
166 gotpty:
167 	dup2(f, 0);
168 	line[strlen("/dev/")] = 't';
169 #ifdef DEBUG
170 	{ int tt = open("/dev/tty", 2);
171 	  if (tt > 0) {
172 		ioctl(tt, TIOCNOTTY, 0);
173 		close(tt);
174 	  }
175 	}
176 #endif
177 	t = open(line, 2);
178 	if (t < 0)
179 		fatalperror(f, line, errno);
180 	{ struct sgttyb b;
181 	  gtty(t, &b); b.sg_flags = RAW|ANYP; stty(t, &b);
182 	}
183 	pid = fork();
184 	if (pid < 0)
185 		fatalperror(f, "", errno);
186 	if (pid) {
187 		char pibuf[1024], fibuf[1024], *pbp, *fbp;
188 		int pcc = 0, fcc = 0, on = 1;
189 /* FILE *console = fopen("/dev/console", "w");  */
190 /* setbuf(console, 0); */
191 
192 /* fprintf(console, "f %d p %d\r\n", f, p); */
193 		ioctl(f, FIONBIO, &on);
194 		ioctl(p, FIONBIO, &on);
195 		ioctl(p, TIOCPKT, &on);
196 		signal(SIGTSTP, SIG_IGN);
197 		sigset(SIGCHLD, cleanup);
198 		for (;;) {
199 			int ibits = 0, obits = 0;
200 
201 			if (fcc)
202 				obits |= (1<<p);
203 			else
204 				ibits |= (1<<f);
205 			if (pcc >= 0)
206 				if (pcc)
207 					obits |= (1<<f);
208 				else
209 					ibits |= (1<<p);
210 			if (fcc < 0 && pcc < 0)
211 				break;
212 /* fprintf(console, "ibits from %d obits from %d\r\n", ibits, obits); */
213 			select(16, &ibits, &obits, 0, 0, 0);
214 /* fprintf(console, "ibits %d obits %d\r\n", ibits, obits); */
215 			if (ibits == 0 && obits == 0) {
216 				sleep(5);
217 				continue;
218 			}
219 			if (ibits & (1<<f)) {
220 				fcc = read(f, fibuf, sizeof (fibuf));
221 /* fprintf(console, "%d from f\r\n", fcc); */
222 				if (fcc < 0 && errno == EWOULDBLOCK)
223 					fcc = 0;
224 				else {
225 					if (fcc <= 0)
226 						break;
227 					fbp = fibuf;
228 				}
229 			}
230 			if (ibits & (1<<p)) {
231 				pcc = read(p, pibuf, sizeof (pibuf));
232 /* fprintf(console, "%d from p, buf[0] %x, errno %d\r\n", pcc, buf[0], errno); */
233 				pbp = pibuf;
234 				if (pcc < 0 && errno == EWOULDBLOCK)
235 					pcc = 0;
236 				else if (pcc <= 0)
237 					pcc = -1;
238 				else if (pibuf[0] == 0)
239 					pbp++, pcc--;
240 				else {
241 					if (pibuf[0]&(TIOCPKT_FLUSHWRITE|
242 						      TIOCPKT_NOSTOP|
243 						      TIOCPKT_DOSTOP)) {
244 						int nstop = pibuf[0] &
245 						    (TIOCPKT_NOSTOP|
246 						     TIOCPKT_DOSTOP);
247 						if (nstop)
248 							stop = nstop;
249 						pibuf[0] |= nstop;
250 						send(f,&pibuf[0],1,SOF_OOB);
251 					}
252 					pcc = 0;
253 				}
254 			}
255 			if ((obits & (1<<f)) && pcc > 0) {
256 				cc = write(f, pbp, pcc);
257 /* fprintf(console, "%d of %d to f\r\n", cc, pcc); */
258 				if (cc > 0) {
259 					pcc -= cc;
260 					pbp += cc;
261 				}
262 			}
263 			if ((obits & (1<<p)) && fcc > 0) {
264 				cc = write(p, fbp, fcc);
265 /* fprintf(console, "%d of %d to p\r\n", cc, fcc); */
266 				if (cc > 0) {
267 					fcc -= cc;
268 					fbp += cc;
269 				}
270 			}
271 		}
272 		cleanup();
273 	}
274 	close(f);
275 	close(p);
276 	dup2(t, 0);
277 	dup2(t, 1);
278 	dup2(t, 2);
279 	close(t);
280 	execl("/bin/login", "login", "-r", hp->h_name, 0);
281 	fatalperror(2, "/bin/login", errno);
282 	/*NOTREACHED*/
283 }
284 
285 cleanup()
286 {
287 
288 	rmut();
289 	vhangup();		/* XXX */
290 	shutdown(netf, 2);
291 	kill(0, SIGKILL);
292 	exit(1);
293 }
294 
295 fatal(f, msg)
296 	int f;
297 	char *msg;
298 {
299 	char buf[BUFSIZ];
300 
301 	buf[0] = '\01';		/* error indicator */
302 	(void) sprintf(buf + 1, "rlogind: %s.\n", msg);
303 	(void) write(f, buf, strlen(buf));
304 	exit(1);
305 }
306 
307 fatalperror(f, msg, errno)
308 	int f;
309 	char *msg;
310 	int errno;
311 {
312 	char buf[BUFSIZ];
313 	extern char *sys_errlist[];
314 
315 	(void) sprintf(buf, "%s: %s", msg, sys_errlist[errno]);
316 	fatal(f, buf);
317 }
318 
319 #include <utmp.h>
320 
321 struct	utmp wtmp;
322 char	wtmpf[]	= "/usr/adm/wtmp";
323 char	utmp[] = "/etc/utmp";
324 #define SCPYN(a, b)	strncpy(a, b, sizeof(a))
325 #define SCMPN(a, b)	strncmp(a, b, sizeof(a))
326 
327 rmut()
328 {
329 	register f;
330 	int found = 0;
331 
332 	f = open(utmp, 2);
333 	if (f >= 0) {
334 		while(read(f, (char *)&wtmp, sizeof(wtmp)) == sizeof(wtmp)) {
335 			if (SCMPN(wtmp.ut_line, line+5) || wtmp.ut_name[0]==0)
336 				continue;
337 			lseek(f, -(long)sizeof(wtmp), 1);
338 			SCPYN(wtmp.ut_name, "");
339 			time(&wtmp.ut_time);
340 			write(f, (char *)&wtmp, sizeof(wtmp));
341 			found++;
342 		}
343 		close(f);
344 	}
345 	if (found) {
346 		f = open(wtmpf, 1);
347 		if (f >= 0) {
348 			SCPYN(wtmp.ut_line, line+5);
349 			SCPYN(wtmp.ut_name, "");
350 			time(&wtmp.ut_time);
351 			lseek(f, (long)0, 2);
352 			write(f, (char *)&wtmp, sizeof(wtmp));
353 			close(f);
354 		}
355 	}
356 	chmod(line, 0666);
357 	chown(line, 0, 0);
358 	line[strlen("/dev/")] = 'p';
359 	chmod(line, 0666);
360 	chown(line, 0, 0);
361 }
362