blob: 5c011e15d58b45b8af336c5ca80688488211b652 [file] [log] [blame]
Bernhard Reutner-Fischer2c998512006-04-12 18:09:26 +00001/* vi: set sw=4 ts=4: */
Bernhard Reutner-Fischerdac7ff12006-04-12 17:55:51 +00002/*
Eric Andersen08a72202002-09-30 20:52:10 +00003 * Simple telnet server
4 * Bjorn Wesen, Axis Communications AB (bjornw@axis.com)
5 *
Denys Vlasenko0ef64bd2010-08-16 20:14:46 +02006 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
Eric Andersen08a72202002-09-30 20:52:10 +00007 *
8 * ---------------------------------------------------------------------------
9 * (C) Copyright 2000, Axis Communications AB, LUND, SWEDEN
10 ****************************************************************************
11 *
12 * The telnetd manpage says it all:
13 *
Denys Vlasenkoa4bcbd02009-06-09 23:01:24 +020014 * Telnetd operates by allocating a pseudo-terminal device (see pty(4)) for
15 * a client, then creating a login process which has the slave side of the
16 * pseudo-terminal as stdin, stdout, and stderr. Telnetd manipulates the
17 * master side of the pseudo-terminal, implementing the telnet protocol and
18 * passing characters between the remote client and the login process.
Eric Andersen08a72202002-09-30 20:52:10 +000019 *
20 * Vladimir Oleynik <dzo@simtreas.ru> 2001
Denys Vlasenkoa4bcbd02009-06-09 23:01:24 +020021 * Set process group corrections, initial busybox port
Eric Andersen08a72202002-09-30 20:52:10 +000022 */
Denis Vlasenko75f8d082006-11-22 15:54:52 +000023#define DEBUG 0
Eric Andersen08a72202002-09-30 20:52:10 +000024
Denis Vlasenkob6adbf12007-05-26 19:00:18 +000025#include "libbb.h"
Bernhard Reutner-Fischerf4701962008-01-27 12:50:12 +000026#include <syslog.h>
Rob Landley099ed502006-08-28 09:41:49 +000027
Denis Vlasenko75f8d082006-11-22 15:54:52 +000028#if DEBUG
Denys Vlasenko3a416112010-04-05 22:10:38 +020029# define TELCMDS
30# define TELOPTS
Eric Andersen08a72202002-09-30 20:52:10 +000031#endif
32#include <arpa/telnet.h>
Eric Andersen08a72202002-09-30 20:52:10 +000033
Denys Vlasenko3a416112010-04-05 22:10:38 +020034#if ENABLE_FEATURE_UTMP
35# include <utmp.h> /* LOGIN_PROCESS */
36#endif
37
38
Eric Andersen08a72202002-09-30 20:52:10 +000039struct tsession {
40 struct tsession *next;
Denis Vlasenkod814c982009-02-02 23:43:57 +000041 pid_t shell_pid;
Denys Vlasenko1d77db82009-06-10 13:38:08 +020042 int sockfd_read;
43 int sockfd_write;
44 int ptyfd;
Denis Vlasenko59d7c432007-10-15 15:19:36 +000045
Eric Andersen08a72202002-09-30 20:52:10 +000046 /* two circular buffers */
Denis Vlasenko59d7c432007-10-15 15:19:36 +000047 /*char *buf1, *buf2;*/
Denys Vlasenkoa4bcbd02009-06-09 23:01:24 +020048/*#define TS_BUF1(ts) ts->buf1*/
49/*#define TS_BUF2(ts) TS_BUF2(ts)*/
50#define TS_BUF1(ts) ((unsigned char*)(ts + 1))
51#define TS_BUF2(ts) (((unsigned char*)(ts + 1)) + BUFSIZE)
Eric Andersen08a72202002-09-30 20:52:10 +000052 int rdidx1, wridx1, size1;
53 int rdidx2, wridx2, size2;
54};
55
Denis Vlasenko88308fe2007-06-25 10:35:11 +000056/* Two buffers are directly after tsession in malloced memory.
57 * Make whole thing fit in 4k */
Denis Vlasenko59d7c432007-10-15 15:19:36 +000058enum { BUFSIZE = (4 * 1024 - sizeof(struct tsession)) / 2 };
Denis Vlasenko88308fe2007-06-25 10:35:11 +000059
Eric Andersen08a72202002-09-30 20:52:10 +000060
Denis Vlasenko59d7c432007-10-15 15:19:36 +000061/* Globals */
Denys Vlasenkoa4bcbd02009-06-09 23:01:24 +020062struct globals {
63 struct tsession *sessions;
64 const char *loginpath;
65 const char *issuefile;
66 int maxfd;
Denys Vlasenko98a4c7c2010-02-04 15:00:15 +010067} FIX_ALIASING;
Denys Vlasenkoa4bcbd02009-06-09 23:01:24 +020068#define G (*(struct globals*)&bb_common_bufsiz1)
69#define INIT_G() do { \
70 G.loginpath = "/bin/login"; \
71 G.issuefile = "/etc/issue.net"; \
72} while (0)
Eric Andersen08a72202002-09-30 20:52:10 +000073
74
75/*
Denis Vlasenko59d7c432007-10-15 15:19:36 +000076 Remove all IAC's from buf1 (received IACs are ignored and must be removed
77 so as to not be interpreted by the terminal). Make an uninterrupted
78 string of characters fit for the terminal. Do this by packing
79 all characters meant for the terminal sequentially towards the end of buf.
Eric Andersen08a72202002-09-30 20:52:10 +000080
Denys Vlasenko4c721042010-04-04 23:45:09 +020081 Return a pointer to the beginning of the characters meant for the terminal
Eric Andersen08a72202002-09-30 20:52:10 +000082 and make *num_totty the number of characters that should be sent to
83 the terminal.
84
Denys Vlasenko4c721042010-04-04 23:45:09 +020085 Note - if an IAC (3 byte quantity) starts before (bf + len) but extends
Denis Vlasenko59d7c432007-10-15 15:19:36 +000086 past (bf + len) then that IAC will be left unprocessed and *processed
87 will be less than len.
Eric Andersen08a72202002-09-30 20:52:10 +000088
Denis Vlasenko10916c52007-10-15 17:28:00 +000089 CR-LF ->'s CR mapping is also done here, for convenience.
90
91 NB: may fail to remove iacs which wrap around buffer!
Denis Vlasenko75f8d082006-11-22 15:54:52 +000092 */
Denis Vlasenko10916c52007-10-15 17:28:00 +000093static unsigned char *
Denis Vlasenko75f8d082006-11-22 15:54:52 +000094remove_iacs(struct tsession *ts, int *pnum_totty)
95{
Denys Vlasenkoa4bcbd02009-06-09 23:01:24 +020096 unsigned char *ptr0 = TS_BUF1(ts) + ts->wridx1;
Eric Andersen08a72202002-09-30 20:52:10 +000097 unsigned char *ptr = ptr0;
98 unsigned char *totty = ptr;
99 unsigned char *end = ptr + MIN(BUFSIZE - ts->wridx1, ts->size1);
Eric Andersen08a72202002-09-30 20:52:10 +0000100 int num_totty;
101
102 while (ptr < end) {
103 if (*ptr != IAC) {
Denis Vlasenko10916c52007-10-15 17:28:00 +0000104 char c = *ptr;
105
106 *totty++ = c;
107 ptr++;
Denis Vlasenkob0150d22008-11-07 01:58:21 +0000108 /* We map \r\n ==> \r for pragmatic reasons.
Eric Andersen3752d332003-12-19 11:30:13 +0000109 * Many client implementations send \r\n when
110 * the user hits the CarriageReturn key.
111 */
Denis Vlasenko10916c52007-10-15 17:28:00 +0000112 if (c == '\r' && ptr < end && (*ptr == '\n' || *ptr == '\0'))
Eric Andersen3752d332003-12-19 11:30:13 +0000113 ptr++;
Denis Vlasenkob0150d22008-11-07 01:58:21 +0000114 continue;
Eric Andersen08a72202002-09-30 20:52:10 +0000115 }
Denis Vlasenkob0150d22008-11-07 01:58:21 +0000116
117 if ((ptr+1) >= end)
118 break;
119 if (ptr[1] == NOP) { /* Ignore? (putty keepalive, etc.) */
120 ptr += 2;
121 continue;
122 }
123 if (ptr[1] == IAC) { /* Literal IAC? (emacs M-DEL) */
124 *totty++ = ptr[1];
125 ptr += 2;
126 continue;
127 }
128
129 /*
130 * TELOPT_NAWS support!
131 */
132 if ((ptr+2) >= end) {
Denys Vlasenko1d77db82009-06-10 13:38:08 +0200133 /* Only the beginning of the IAC is in the
Denis Vlasenkob0150d22008-11-07 01:58:21 +0000134 buffer we were asked to process, we can't
Denys Vlasenko1d77db82009-06-10 13:38:08 +0200135 process this char */
Denis Vlasenkob0150d22008-11-07 01:58:21 +0000136 break;
137 }
138 /*
139 * IAC -> SB -> TELOPT_NAWS -> 4-byte -> IAC -> SE
140 */
141 if (ptr[1] == SB && ptr[2] == TELOPT_NAWS) {
142 struct winsize ws;
143 if ((ptr+8) >= end)
144 break; /* incomplete, can't process */
145 ws.ws_col = (ptr[3] << 8) | ptr[4];
146 ws.ws_row = (ptr[5] << 8) | ptr[6];
147 ioctl(ts->ptyfd, TIOCSWINSZ, (char *)&ws);
148 ptr += 9;
149 continue;
150 }
151 /* skip 3-byte IAC non-SB cmd */
152#if DEBUG
153 fprintf(stderr, "Ignoring IAC %s,%s\n",
154 TELCMD(ptr[1]), TELOPT(ptr[2]));
155#endif
156 ptr += 3;
Eric Andersen08a72202002-09-30 20:52:10 +0000157 }
158
Denis Vlasenko0de37e12007-10-17 11:08:53 +0000159 num_totty = totty - ptr0;
Eric Andersen08a72202002-09-30 20:52:10 +0000160 *pnum_totty = num_totty;
Denys Vlasenko1d77db82009-06-10 13:38:08 +0200161 /* The difference between ptr and totty is number of iacs
162 we removed from the stream. Adjust buf1 accordingly */
Denis Vlasenko10916c52007-10-15 17:28:00 +0000163 if ((ptr - totty) == 0) /* 99.999% of cases */
164 return ptr0;
165 ts->wridx1 += ptr - totty;
166 ts->size1 -= ptr - totty;
Denys Vlasenko1d77db82009-06-10 13:38:08 +0200167 /* Move chars meant for the terminal towards the end of the buffer */
Eric Andersen08a72202002-09-30 20:52:10 +0000168 return memmove(ptr - num_totty, ptr0, num_totty);
169}
170
Denis Vlasenko9f2f8082008-11-11 02:56:39 +0000171/*
Denis Vlasenko81c6a912008-11-12 21:14:50 +0000172 * Converting single IAC into double on output
Denis Vlasenko9f2f8082008-11-11 02:56:39 +0000173 */
174static size_t iac_safe_write(int fd, const char *buf, size_t count)
175{
Denis Vlasenko81c6a912008-11-12 21:14:50 +0000176 const char *IACptr;
Denis Vlasenko9f2f8082008-11-11 02:56:39 +0000177 size_t wr, rc, total;
178
179 total = 0;
180 while (1) {
181 if (count == 0)
182 return total;
Denis Vlasenko81c6a912008-11-12 21:14:50 +0000183 if (*buf == (char)IAC) {
184 static const char IACIAC[] ALIGN1 = { IAC, IAC };
185 rc = safe_write(fd, IACIAC, 2);
Denis Vlasenko9f2f8082008-11-11 02:56:39 +0000186 if (rc != 2)
187 break;
188 buf++;
189 total++;
190 count--;
191 continue;
192 }
Denis Vlasenko81c6a912008-11-12 21:14:50 +0000193 /* count != 0, *buf != IAC */
194 IACptr = memchr(buf, IAC, count);
Denis Vlasenko9f2f8082008-11-11 02:56:39 +0000195 wr = count;
Denis Vlasenko81c6a912008-11-12 21:14:50 +0000196 if (IACptr)
197 wr = IACptr - buf;
Denis Vlasenko9f2f8082008-11-11 02:56:39 +0000198 rc = safe_write(fd, buf, wr);
199 if (rc != wr)
200 break;
201 buf += rc;
202 total += rc;
203 count -= rc;
204 }
205 /* here: rc - result of last short write */
206 if ((ssize_t)rc < 0) { /* error? */
207 if (total == 0)
208 return rc;
209 rc = 0;
210 }
211 return total + rc;
212}
Eric Andersen08a72202002-09-30 20:52:10 +0000213
Denys Vlasenkoa4bcbd02009-06-09 23:01:24 +0200214/* Must match getopt32 string */
215enum {
216 OPT_WATCHCHILD = (1 << 2), /* -K */
217 OPT_INETD = (1 << 3) * ENABLE_FEATURE_TELNETD_STANDALONE, /* -i */
Denys Vlasenkoed1667e2009-09-04 02:21:13 +0200218 OPT_PORT = (1 << 4) * ENABLE_FEATURE_TELNETD_STANDALONE, /* -p PORT */
Denys Vlasenkoa4bcbd02009-06-09 23:01:24 +0200219 OPT_FOREGROUND = (1 << 6) * ENABLE_FEATURE_TELNETD_STANDALONE, /* -F */
Denys Vlasenkoed1667e2009-09-04 02:21:13 +0200220 OPT_SYSLOG = (1 << 7) * ENABLE_FEATURE_TELNETD_INETD_WAIT, /* -S */
221 OPT_WAIT = (1 << 8) * ENABLE_FEATURE_TELNETD_INETD_WAIT, /* -w SEC */
Denys Vlasenkoa4bcbd02009-06-09 23:01:24 +0200222};
223
Eric Andersen08a72202002-09-30 20:52:10 +0000224static struct tsession *
Denis Vlasenko75f8d082006-11-22 15:54:52 +0000225make_new_session(
Denys Vlasenko1d77db82009-06-10 13:38:08 +0200226 IF_FEATURE_TELNETD_STANDALONE(int sock)
Denis Vlasenko5e34ff22009-04-21 11:09:40 +0000227 IF_NOT_FEATURE_TELNETD_STANDALONE(void)
Denis Vlasenko75f8d082006-11-22 15:54:52 +0000228) {
Denys Vlasenkof6916db2010-04-06 17:43:29 +0200229#if !ENABLE_FEATURE_TELNETD_STANDALONE
Denys Vlasenkoff0e8752010-05-10 04:16:43 +0200230 enum { sock = 0 };
Denys Vlasenkof6916db2010-04-06 17:43:29 +0200231#endif
Denis Vlasenko88308fe2007-06-25 10:35:11 +0000232 const char *login_argv[2];
Eric Andersen08a72202002-09-30 20:52:10 +0000233 struct termios termbuf;
Denis Vlasenko75f8d082006-11-22 15:54:52 +0000234 int fd, pid;
Denis Vlasenko85c24712008-03-17 09:04:04 +0000235 char tty_name[GETPTY_BUFSIZE];
Rob Landley1ec5b292006-05-29 07:42:02 +0000236 struct tsession *ts = xzalloc(sizeof(struct tsession) + BUFSIZE * 2);
Eric Andersen08a72202002-09-30 20:52:10 +0000237
Denis Vlasenko59d7c432007-10-15 15:19:36 +0000238 /*ts->buf1 = (char *)(ts + 1);*/
239 /*ts->buf2 = ts->buf1 + BUFSIZE;*/
Eric Andersen08a72202002-09-30 20:52:10 +0000240
Denys Vlasenko1d77db82009-06-10 13:38:08 +0200241 /* Got a new connection, set up a tty */
Bernhard Reutner-Fischerae4342c2008-05-19 08:18:50 +0000242 fd = xgetpty(tty_name);
Denys Vlasenkoa4bcbd02009-06-09 23:01:24 +0200243 if (fd > G.maxfd)
244 G.maxfd = fd;
Denis Vlasenko59d7c432007-10-15 15:19:36 +0000245 ts->ptyfd = fd;
246 ndelay_on(fd);
Denys Vlasenko1d77db82009-06-10 13:38:08 +0200247 close_on_exec_on(fd);
248
Denis Vlasenko6d044352008-11-09 00:44:40 +0000249 /* SO_KEEPALIVE by popular demand */
250 setsockopt(sock, SOL_SOCKET, SO_KEEPALIVE, &const_int_1, sizeof(const_int_1));
Denys Vlasenkof6916db2010-04-06 17:43:29 +0200251#if ENABLE_FEATURE_TELNETD_STANDALONE
Denys Vlasenko1d77db82009-06-10 13:38:08 +0200252 ts->sockfd_read = sock;
Denis Vlasenkof472b232007-10-16 21:35:17 +0000253 ndelay_on(sock);
Denys Vlasenko1d77db82009-06-10 13:38:08 +0200254 if (sock == 0) { /* We are called with fd 0 - we are in inetd mode */
Denis Vlasenko9e237672007-10-17 11:18:49 +0000255 sock++; /* so use fd 1 for output */
256 ndelay_on(sock);
257 }
Denis Vlasenkof472b232007-10-16 21:35:17 +0000258 ts->sockfd_write = sock;
Denys Vlasenkoa4bcbd02009-06-09 23:01:24 +0200259 if (sock > G.maxfd)
260 G.maxfd = sock;
Denis Vlasenko75f8d082006-11-22 15:54:52 +0000261#else
Denis Vlasenko59d7c432007-10-15 15:19:36 +0000262 /* ts->sockfd_read = 0; - done by xzalloc */
Denis Vlasenkof472b232007-10-16 21:35:17 +0000263 ts->sockfd_write = 1;
Denis Vlasenko75f8d082006-11-22 15:54:52 +0000264 ndelay_on(0);
265 ndelay_on(1);
266#endif
Denys Vlasenko1d77db82009-06-10 13:38:08 +0200267
Eric Andersen08a72202002-09-30 20:52:10 +0000268 /* Make the telnet client understand we will echo characters so it
269 * should not do it locally. We don't tell the client to run linemode,
270 * because we want to handle line editing and tab completion and other
Denis Vlasenko75f8d082006-11-22 15:54:52 +0000271 * stuff that requires char-by-char support. */
Denis Vlasenko59d7c432007-10-15 15:19:36 +0000272 {
273 static const char iacs_to_send[] ALIGN1 = {
274 IAC, DO, TELOPT_ECHO,
275 IAC, DO, TELOPT_NAWS,
Denis Vlasenkod814c982009-02-02 23:43:57 +0000276 /* This requires telnetd.ctrlSQ.patch (incomplete) */
277 /* IAC, DO, TELOPT_LFLOW, */
Denis Vlasenko59d7c432007-10-15 15:19:36 +0000278 IAC, WILL, TELOPT_ECHO,
279 IAC, WILL, TELOPT_SGA
280 };
Denis Vlasenko9f2f8082008-11-11 02:56:39 +0000281 /* This confuses iac_safe_write(), it will try to duplicate
282 * each IAC... */
Denys Vlasenkoa4bcbd02009-06-09 23:01:24 +0200283 //memcpy(TS_BUF2(ts), iacs_to_send, sizeof(iacs_to_send));
Denis Vlasenko9f2f8082008-11-11 02:56:39 +0000284 //ts->rdidx2 = sizeof(iacs_to_send);
285 //ts->size2 = sizeof(iacs_to_send);
Denis Vlasenko81c6a912008-11-12 21:14:50 +0000286 /* So just stuff it into TCP stream! (no error check...) */
287#if ENABLE_FEATURE_TELNETD_STANDALONE
Denis Vlasenko9f2f8082008-11-11 02:56:39 +0000288 safe_write(sock, iacs_to_send, sizeof(iacs_to_send));
Denis Vlasenko81c6a912008-11-12 21:14:50 +0000289#else
290 safe_write(1, iacs_to_send, sizeof(iacs_to_send));
291#endif
292 /*ts->rdidx2 = 0; - xzalloc did it */
Denis Vlasenko9f2f8082008-11-11 02:56:39 +0000293 /*ts->size2 = 0;*/
Denis Vlasenko59d7c432007-10-15 15:19:36 +0000294 }
Eric Andersen08a72202002-09-30 20:52:10 +0000295
Denys Vlasenko8131eea2009-11-02 14:19:51 +0100296 fflush_all();
Denis Vlasenko59d7c432007-10-15 15:19:36 +0000297 pid = vfork(); /* NOMMU-friendly */
Denis Vlasenko75f8d082006-11-22 15:54:52 +0000298 if (pid < 0) {
299 free(ts);
300 close(fd);
Denis Vlasenko23c81282007-10-16 22:01:23 +0000301 /* sock will be closed by caller */
Denis Vlasenko59d7c432007-10-15 15:19:36 +0000302 bb_perror_msg("vfork");
Denis Vlasenko75f8d082006-11-22 15:54:52 +0000303 return NULL;
Eric Andersen08a72202002-09-30 20:52:10 +0000304 }
Denis Vlasenko75f8d082006-11-22 15:54:52 +0000305 if (pid > 0) {
Denis Vlasenko59d7c432007-10-15 15:19:36 +0000306 /* Parent */
Denis Vlasenko2450c452007-10-15 22:09:15 +0000307 ts->shell_pid = pid;
Denis Vlasenko75f8d082006-11-22 15:54:52 +0000308 return ts;
Eric Andersen08a72202002-09-30 20:52:10 +0000309 }
Denis Vlasenkof7996f32007-01-11 17:20:00 +0000310
Denis Vlasenko59d7c432007-10-15 15:19:36 +0000311 /* Child */
312 /* Careful - we are after vfork! */
Eric Andersen08a72202002-09-30 20:52:10 +0000313
Denis Vlasenkod814c982009-02-02 23:43:57 +0000314 /* Restore default signal handling ASAP */
Denis Vlasenko25591c32008-02-16 22:58:56 +0000315 bb_signals((1 << SIGCHLD) + (1 << SIGPIPE), SIG_DFL);
Denis Vlasenko018b1552007-11-06 01:38:46 +0000316
Denys Vlasenkof6916db2010-04-06 17:43:29 +0200317 if (ENABLE_FEATURE_UTMP) {
318 len_and_sockaddr *lsa = get_peer_lsa(sock);
319 char *hostname = NULL;
320 if (lsa) {
321 hostname = xmalloc_sockaddr2dotted(&lsa->u.sa);
322 free(lsa);
323 }
324 write_new_utmp(pid, LOGIN_PROCESS, tty_name, /*username:*/ "LOGIN", hostname);
325 free(hostname);
326 }
327
Denis Vlasenkod814c982009-02-02 23:43:57 +0000328 /* Make new session and process group */
329 setsid();
330
Denys Vlasenko1d77db82009-06-10 13:38:08 +0200331 /* Open the child's side of the tty */
Denis Vlasenko9af7c9d2007-01-19 21:19:35 +0000332 /* NB: setsid() disconnects from any previous ctty's. Therefore
333 * we must open child's side of the tty AFTER setsid! */
Denys Vlasenko1d77db82009-06-10 13:38:08 +0200334 close(0);
Denis Vlasenko1101d1c2008-07-21 09:22:28 +0000335 xopen(tty_name, O_RDWR); /* becomes our ctty */
336 xdup2(0, 1);
337 xdup2(0, 2);
Denys Vlasenko3a416112010-04-05 22:10:38 +0200338 pid = getpid();
339 tcsetpgrp(0, pid); /* switch this tty's process group to us */
340
Denys Vlasenko1d77db82009-06-10 13:38:08 +0200341 /* The pseudo-terminal allocated to the client is configured to operate
342 * in cooked mode, and with XTABS CRMOD enabled (see tty(4)) */
Denis Vlasenko75f8d082006-11-22 15:54:52 +0000343 tcgetattr(0, &termbuf);
344 termbuf.c_lflag |= ECHO; /* if we use readline we dont want this */
Denis Vlasenko59d7c432007-10-15 15:19:36 +0000345 termbuf.c_oflag |= ONLCR | XTABS;
Denis Vlasenko75f8d082006-11-22 15:54:52 +0000346 termbuf.c_iflag |= ICRNL;
347 termbuf.c_iflag &= ~IXOFF;
348 /*termbuf.c_lflag &= ~ICANON;*/
Denis Vlasenko202ac502008-11-05 13:20:58 +0000349 tcsetattr_stdin_TCSANOW(&termbuf);
Denis Vlasenko75f8d082006-11-22 15:54:52 +0000350
Denys Vlasenko8131eea2009-11-02 14:19:51 +0100351 /* Uses FILE-based I/O to stdout, but does fflush_all(),
Denis Vlasenko59d7c432007-10-15 15:19:36 +0000352 * so should be safe with vfork.
353 * I fear, though, that some users will have ridiculously big
Denis Vlasenko018b1552007-11-06 01:38:46 +0000354 * issue files, and they may block writing to fd 1,
355 * (parent is supposed to read it, but parent waits
356 * for vforked child to exec!) */
Denys Vlasenkoa4bcbd02009-06-09 23:01:24 +0200357 print_login_issue(G.issuefile, tty_name);
Denis Vlasenko75f8d082006-11-22 15:54:52 +0000358
Denis Vlasenko59d7c432007-10-15 15:19:36 +0000359 /* Exec shell / login / whatever */
Denys Vlasenkoa4bcbd02009-06-09 23:01:24 +0200360 login_argv[0] = G.loginpath;
Denis Vlasenko88308fe2007-06-25 10:35:11 +0000361 login_argv[1] = NULL;
Denis Vlasenko018b1552007-11-06 01:38:46 +0000362 /* exec busybox applet (if PREFER_APPLETS=y), if that fails,
Denys Vlasenko1d77db82009-06-10 13:38:08 +0200363 * exec external program.
364 * NB: sock is either 0 or has CLOEXEC set on it.
365 * fd has CLOEXEC set on it too. These two fds will be closed here.
366 */
Denys Vlasenkoa4bcbd02009-06-09 23:01:24 +0200367 BB_EXECVP(G.loginpath, (char **)login_argv);
Denis Vlasenko018b1552007-11-06 01:38:46 +0000368 /* _exit is safer with vfork, and we shouldn't send message
Denis Vlasenko2450c452007-10-15 22:09:15 +0000369 * to remote clients anyway */
Denys Vlasenkoa4bcbd02009-06-09 23:01:24 +0200370 _exit(EXIT_FAILURE); /*bb_perror_msg_and_die("execv %s", G.loginpath);*/
Eric Andersen08a72202002-09-30 20:52:10 +0000371}
372
Denis Vlasenko75f8d082006-11-22 15:54:52 +0000373#if ENABLE_FEATURE_TELNETD_STANDALONE
374
Eric Andersen08a72202002-09-30 20:52:10 +0000375static void
376free_session(struct tsession *ts)
377{
Denys Vlasenko3a416112010-04-05 22:10:38 +0200378 struct tsession *t;
Eric Andersen08a72202002-09-30 20:52:10 +0000379
Denis Vlasenkoe87b8682007-10-17 14:33:31 +0000380 if (option_mask32 & OPT_INETD)
Bernhard Reutner-Fischer636a1f82008-05-19 09:29:47 +0000381 exit(EXIT_SUCCESS);
Denis Vlasenkoe87b8682007-10-17 14:33:31 +0000382
Denis Vlasenko59d7c432007-10-15 15:19:36 +0000383 /* Unlink this telnet session from the session list */
Denys Vlasenko3a416112010-04-05 22:10:38 +0200384 t = G.sessions;
Mike Frysinger731f81c2006-05-10 15:23:12 +0000385 if (t == ts)
Denys Vlasenkoa4bcbd02009-06-09 23:01:24 +0200386 G.sessions = ts->next;
Eric Andersen08a72202002-09-30 20:52:10 +0000387 else {
Denis Vlasenko75f8d082006-11-22 15:54:52 +0000388 while (t->next != ts)
Eric Andersen08a72202002-09-30 20:52:10 +0000389 t = t->next;
390 t->next = ts->next;
391 }
392
Denis Vlasenkof472b232007-10-16 21:35:17 +0000393#if 0
Denis Vlasenko59d7c432007-10-15 15:19:36 +0000394 /* It was said that "normal" telnetd just closes ptyfd,
395 * doesn't send SIGKILL. When we close ptyfd,
396 * kernel sends SIGHUP to processes having slave side opened. */
Denis Vlasenkof472b232007-10-16 21:35:17 +0000397 kill(ts->shell_pid, SIGKILL);
Denis Vlasenkod814c982009-02-02 23:43:57 +0000398 waitpid(ts->shell_pid, NULL, 0);
Denis Vlasenkof472b232007-10-16 21:35:17 +0000399#endif
Eric Andersen08a72202002-09-30 20:52:10 +0000400 close(ts->ptyfd);
Denis Vlasenko75f8d082006-11-22 15:54:52 +0000401 close(ts->sockfd_read);
Denis Vlasenkof472b232007-10-16 21:35:17 +0000402 /* We do not need to close(ts->sockfd_write), it's the same
403 * as sockfd_read unless we are in inetd mode. But in inetd mode
Denis Vlasenkoe87b8682007-10-17 14:33:31 +0000404 * we do not reach this */
Eric Andersen08a72202002-09-30 20:52:10 +0000405 free(ts);
Denis Vlasenko75f8d082006-11-22 15:54:52 +0000406
Denis Vlasenko59d7c432007-10-15 15:19:36 +0000407 /* Scan all sessions and find new maxfd */
Denys Vlasenkoa4bcbd02009-06-09 23:01:24 +0200408 G.maxfd = 0;
409 ts = G.sessions;
Denis Vlasenko75f8d082006-11-22 15:54:52 +0000410 while (ts) {
Denys Vlasenkoa4bcbd02009-06-09 23:01:24 +0200411 if (G.maxfd < ts->ptyfd)
412 G.maxfd = ts->ptyfd;
413 if (G.maxfd < ts->sockfd_read)
414 G.maxfd = ts->sockfd_read;
Denis Vlasenkof472b232007-10-16 21:35:17 +0000415#if 0
416 /* Again, sockfd_write == sockfd_read here */
Denys Vlasenkoa4bcbd02009-06-09 23:01:24 +0200417 if (G.maxfd < ts->sockfd_write)
418 G.maxfd = ts->sockfd_write;
Denis Vlasenkof472b232007-10-16 21:35:17 +0000419#endif
Denis Vlasenko75f8d082006-11-22 15:54:52 +0000420 ts = ts->next;
421 }
Eric Andersen08a72202002-09-30 20:52:10 +0000422}
Denis Vlasenko75f8d082006-11-22 15:54:52 +0000423
Denis Vlasenko75f8d082006-11-22 15:54:52 +0000424#else /* !FEATURE_TELNETD_STANDALONE */
425
Bernhard Reutner-Fischer636a1f82008-05-19 09:29:47 +0000426/* Used in main() only, thus "return 0" actually is exit(EXIT_SUCCESS). */
Denis Vlasenkoe87b8682007-10-17 14:33:31 +0000427#define free_session(ts) return 0
Denis Vlasenko75f8d082006-11-22 15:54:52 +0000428
429#endif
430
Denis Vlasenkoa60f84e2008-07-05 09:18:54 +0000431static void handle_sigchld(int sig UNUSED_PARAM)
Denis Vlasenko2450c452007-10-15 22:09:15 +0000432{
433 pid_t pid;
434 struct tsession *ts;
Denys Vlasenko3a416112010-04-05 22:10:38 +0200435 int save_errno = errno;
Denis Vlasenko2450c452007-10-15 22:09:15 +0000436
Denis Vlasenko018b1552007-11-06 01:38:46 +0000437 /* Looping: more than one child may have exited */
438 while (1) {
Denis Vlasenkofb0eba72008-01-02 19:55:04 +0000439 pid = wait_any_nohang(NULL);
Denis Vlasenko018b1552007-11-06 01:38:46 +0000440 if (pid <= 0)
441 break;
Denys Vlasenkoa4bcbd02009-06-09 23:01:24 +0200442 ts = G.sessions;
Denis Vlasenko2450c452007-10-15 22:09:15 +0000443 while (ts) {
444 if (ts->shell_pid == pid) {
445 ts->shell_pid = -1;
Denys Vlasenko3a416112010-04-05 22:10:38 +0200446// man utmp:
447// When init(8) finds that a process has exited, it locates its utmp entry
448// by ut_pid, sets ut_type to DEAD_PROCESS, and clears ut_user, ut_host
449// and ut_time with null bytes.
450// [same applies to other processes which maintain utmp entries, like telnetd]
451//
452// We do not bother actually clearing fields:
453// it might be interesting to know who was logged in and from where
454 update_utmp(pid, DEAD_PROCESS, /*tty_name:*/ NULL, /*username:*/ NULL, /*hostname:*/ NULL);
Denis Vlasenko018b1552007-11-06 01:38:46 +0000455 break;
Denis Vlasenko2450c452007-10-15 22:09:15 +0000456 }
457 ts = ts->next;
458 }
459 }
Denys Vlasenko3a416112010-04-05 22:10:38 +0200460
461 errno = save_errno;
Denis Vlasenko2450c452007-10-15 22:09:15 +0000462}
463
Denis Vlasenko9b49a5e2007-10-11 10:05:36 +0000464int telnetd_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
Denis Vlasenkoa60f84e2008-07-05 09:18:54 +0000465int telnetd_main(int argc UNUSED_PARAM, char **argv)
Eric Andersen08a72202002-09-30 20:52:10 +0000466{
Eric Andersen08a72202002-09-30 20:52:10 +0000467 fd_set rdfdset, wrfdset;
Denis Vlasenko75f8d082006-11-22 15:54:52 +0000468 unsigned opt;
Denis Vlasenko10916c52007-10-15 17:28:00 +0000469 int count;
Denis Vlasenko75f8d082006-11-22 15:54:52 +0000470 struct tsession *ts;
471#if ENABLE_FEATURE_TELNETD_STANDALONE
472#define IS_INETD (opt & OPT_INETD)
Denys Vlasenkoed1667e2009-09-04 02:21:13 +0200473 int master_fd = master_fd; /* for compiler */
474 int sec_linger = sec_linger;
Denis Vlasenko75f8d082006-11-22 15:54:52 +0000475 char *opt_bindaddr = NULL;
476 char *opt_portnbr;
477#else
478 enum {
479 IS_INETD = 1,
480 master_fd = -1,
Denis Vlasenko75f8d082006-11-22 15:54:52 +0000481 };
Glenn L McGrathc2b91862003-09-12 11:27:15 +0000482#endif
Denys Vlasenkoa4bcbd02009-06-09 23:01:24 +0200483 INIT_G();
484
Denys Vlasenkoed1667e2009-09-04 02:21:13 +0200485 /* -w NUM, and implies -F. -w and -i don't mix */
486 IF_FEATURE_TELNETD_INETD_WAIT(opt_complementary = "wF:w+:i--w:w--i";)
Denis Vlasenko2450c452007-10-15 22:09:15 +0000487 /* Even if !STANDALONE, we accept (and ignore) -i, thus people
Denis Vlasenko59d7c432007-10-15 15:19:36 +0000488 * don't need to guess whether it's ok to pass -i to us */
Denys Vlasenkoed1667e2009-09-04 02:21:13 +0200489 opt = getopt32(argv, "f:l:Ki"
490 IF_FEATURE_TELNETD_STANDALONE("p:b:F")
491 IF_FEATURE_TELNETD_INETD_WAIT("Sw:"),
Denys Vlasenkoa4bcbd02009-06-09 23:01:24 +0200492 &G.issuefile, &G.loginpath
Denys Vlasenkoed1667e2009-09-04 02:21:13 +0200493 IF_FEATURE_TELNETD_STANDALONE(, &opt_portnbr, &opt_bindaddr)
494 IF_FEATURE_TELNETD_INETD_WAIT(, &sec_linger)
495 );
Denis Vlasenko2450c452007-10-15 22:09:15 +0000496 if (!IS_INETD /*&& !re_execed*/) {
497 /* inform that we start in standalone mode?
498 * May be useful when people forget to give -i */
499 /*bb_error_msg("listening for connections");*/
500 if (!(opt & OPT_FOREGROUND)) {
501 /* DAEMON_CHDIR_ROOT was giving inconsistent
Denis Vlasenko008eda22007-10-16 10:47:27 +0000502 * behavior with/without -F, -i */
Denis Vlasenko018b1552007-11-06 01:38:46 +0000503 bb_daemonize_or_rexec(0 /*was DAEMON_CHDIR_ROOT*/, argv);
Denis Vlasenko2450c452007-10-15 22:09:15 +0000504 }
505 }
Denis Vlasenko75f8d082006-11-22 15:54:52 +0000506 /* Redirect log to syslog early, if needed */
Denys Vlasenkoed1667e2009-09-04 02:21:13 +0200507 if (IS_INETD || (opt & OPT_SYSLOG) || !(opt & OPT_FOREGROUND)) {
Denis Vlasenko5e4fda02009-03-08 23:46:48 +0000508 openlog(applet_name, LOG_PID, LOG_DAEMON);
Denis Vlasenko75f8d082006-11-22 15:54:52 +0000509 logmode = LOGMODE_SYSLOG;
510 }
Denis Vlasenko75f8d082006-11-22 15:54:52 +0000511#if ENABLE_FEATURE_TELNETD_STANDALONE
512 if (IS_INETD) {
Denys Vlasenko1d77db82009-06-10 13:38:08 +0200513 G.sessions = make_new_session(0);
Denys Vlasenkoa4bcbd02009-06-09 23:01:24 +0200514 if (!G.sessions) /* pty opening or vfork problem, exit */
Denys Vlasenkoed1667e2009-09-04 02:21:13 +0200515 return 1; /* make_new_session printed error message */
Denis Vlasenko75f8d082006-11-22 15:54:52 +0000516 } else {
Denys Vlasenkoed1667e2009-09-04 02:21:13 +0200517 master_fd = 0;
518 if (!(opt & OPT_WAIT)) {
519 unsigned portnbr = 23;
520 if (opt & OPT_PORT)
521 portnbr = xatou16(opt_portnbr);
522 master_fd = create_and_bind_stream_or_die(opt_bindaddr, portnbr);
523 xlisten(master_fd, 1);
524 }
Denys Vlasenko1d77db82009-06-10 13:38:08 +0200525 close_on_exec_on(master_fd);
Denis Vlasenko75f8d082006-11-22 15:54:52 +0000526 }
Rob Landley00e76cb2005-05-10 23:53:33 +0000527#else
Denys Vlasenkoa4bcbd02009-06-09 23:01:24 +0200528 G.sessions = make_new_session();
529 if (!G.sessions) /* pty opening or vfork problem, exit */
Denys Vlasenkoed1667e2009-09-04 02:21:13 +0200530 return 1; /* make_new_session printed error message */
Rob Landley00e76cb2005-05-10 23:53:33 +0000531#endif
Eric Andersen08a72202002-09-30 20:52:10 +0000532
Denis Vlasenko75f8d082006-11-22 15:54:52 +0000533 /* We don't want to die if just one session is broken */
534 signal(SIGPIPE, SIG_IGN);
Eric Andersen08a72202002-09-30 20:52:10 +0000535
Denis Vlasenko2450c452007-10-15 22:09:15 +0000536 if (opt & OPT_WATCHCHILD)
537 signal(SIGCHLD, handle_sigchld);
Denis Vlasenko018b1552007-11-06 01:38:46 +0000538 else /* prevent dead children from becoming zombies */
539 signal(SIGCHLD, SIG_IGN);
Denis Vlasenko2450c452007-10-15 22:09:15 +0000540
Denis Vlasenko59d7c432007-10-15 15:19:36 +0000541/*
Denys Vlasenko1d77db82009-06-10 13:38:08 +0200542 This is how the buffers are used. The arrows indicate data flow.
543
Denis Vlasenko59d7c432007-10-15 15:19:36 +0000544 +-------+ wridx1++ +------+ rdidx1++ +----------+
545 | | <-------------- | buf1 | <-------------- | |
546 | | size1-- +------+ size1++ | |
547 | pty | | socket |
548 | | rdidx2++ +------+ wridx2++ | |
549 | | --------------> | buf2 | --------------> | |
550 +-------+ size2++ +------+ size2-- +----------+
551
552 size1: "how many bytes are buffered for pty between rdidx1 and wridx1?"
553 size2: "how many bytes are buffered for socket between rdidx2 and wridx2?"
554
555 Each session has got two buffers. Buffers are circular. If sizeN == 0,
556 buffer is empty. If sizeN == BUFSIZE, buffer is full. In both these cases
557 rdidxN == wridxN.
558*/
Denis Vlasenko75f8d082006-11-22 15:54:52 +0000559 again:
560 FD_ZERO(&rdfdset);
561 FD_ZERO(&wrfdset);
Eric Andersen08a72202002-09-30 20:52:10 +0000562
Denis Vlasenko59d7c432007-10-15 15:19:36 +0000563 /* Select on the master socket, all telnet sockets and their
564 * ptys if there is room in their session buffers.
565 * NB: scalability problem: we recalculate entire bitmap
566 * before each select. Can be a problem with 500+ connections. */
Denys Vlasenkoa4bcbd02009-06-09 23:01:24 +0200567 ts = G.sessions;
Denis Vlasenko75f8d082006-11-22 15:54:52 +0000568 while (ts) {
Denys Vlasenko1d77db82009-06-10 13:38:08 +0200569 struct tsession *next = ts->next; /* in case we free ts */
Denis Vlasenko2450c452007-10-15 22:09:15 +0000570 if (ts->shell_pid == -1) {
Denis Vlasenko018b1552007-11-06 01:38:46 +0000571 /* Child died and we detected that */
Denis Vlasenko2450c452007-10-15 22:09:15 +0000572 free_session(ts);
573 } else {
574 if (ts->size1 > 0) /* can write to pty */
575 FD_SET(ts->ptyfd, &wrfdset);
576 if (ts->size1 < BUFSIZE) /* can read from socket */
577 FD_SET(ts->sockfd_read, &rdfdset);
578 if (ts->size2 > 0) /* can write to socket */
579 FD_SET(ts->sockfd_write, &wrfdset);
580 if (ts->size2 < BUFSIZE) /* can read from pty */
581 FD_SET(ts->ptyfd, &rdfdset);
582 }
583 ts = next;
584 }
585 if (!IS_INETD) {
586 FD_SET(master_fd, &rdfdset);
587 /* This is needed because free_session() does not
Denis Vlasenko018b1552007-11-06 01:38:46 +0000588 * take master_fd into account when it finds new
Denis Vlasenko2450c452007-10-15 22:09:15 +0000589 * maxfd among remaining fd's */
Denys Vlasenkoa4bcbd02009-06-09 23:01:24 +0200590 if (master_fd > G.maxfd)
591 G.maxfd = master_fd;
Denis Vlasenko75f8d082006-11-22 15:54:52 +0000592 }
593
Denys Vlasenkoed1667e2009-09-04 02:21:13 +0200594 {
Denys Vlasenkoed1667e2009-09-04 02:21:13 +0200595 struct timeval *tv_ptr = NULL;
Denys Vlasenko36df0482009-10-19 16:07:28 +0200596#if ENABLE_FEATURE_TELNETD_INETD_WAIT
597 struct timeval tv;
Denys Vlasenkoed1667e2009-09-04 02:21:13 +0200598 if ((opt & OPT_WAIT) && !G.sessions) {
599 tv.tv_sec = sec_linger;
600 tv.tv_usec = 0;
601 tv_ptr = &tv;
602 }
Denys Vlasenko36df0482009-10-19 16:07:28 +0200603#endif
Denys Vlasenkoed1667e2009-09-04 02:21:13 +0200604 count = select(G.maxfd + 1, &rdfdset, &wrfdset, NULL, tv_ptr);
605 }
606 if (count == 0) /* "telnetd -w SEC" timed out */
607 return 0;
Denis Vlasenko10916c52007-10-15 17:28:00 +0000608 if (count < 0)
Denis Vlasenko59d7c432007-10-15 15:19:36 +0000609 goto again; /* EINTR or ENOMEM */
Denis Vlasenko75f8d082006-11-22 15:54:52 +0000610
611#if ENABLE_FEATURE_TELNETD_STANDALONE
Denys Vlasenko1d77db82009-06-10 13:38:08 +0200612 /* Check for and accept new sessions */
Denis Vlasenko75f8d082006-11-22 15:54:52 +0000613 if (!IS_INETD && FD_ISSET(master_fd, &rdfdset)) {
Denis Vlasenko75f8d082006-11-22 15:54:52 +0000614 int fd;
Denis Vlasenko75f8d082006-11-22 15:54:52 +0000615 struct tsession *new_ts;
616
Denis Vlasenko59d7c432007-10-15 15:19:36 +0000617 fd = accept(master_fd, NULL, NULL);
Denis Vlasenko75f8d082006-11-22 15:54:52 +0000618 if (fd < 0)
619 goto again;
Denys Vlasenko1d77db82009-06-10 13:38:08 +0200620 close_on_exec_on(fd);
621
622 /* Create a new session and link it into active list */
623 new_ts = make_new_session(fd);
Denis Vlasenko75f8d082006-11-22 15:54:52 +0000624 if (new_ts) {
Denys Vlasenkoa4bcbd02009-06-09 23:01:24 +0200625 new_ts->next = G.sessions;
626 G.sessions = new_ts;
Denis Vlasenko75f8d082006-11-22 15:54:52 +0000627 } else {
628 close(fd);
Eric Andersen08a72202002-09-30 20:52:10 +0000629 }
Denis Vlasenko75f8d082006-11-22 15:54:52 +0000630 }
631#endif
Eric Andersen08a72202002-09-30 20:52:10 +0000632
Denys Vlasenko1d77db82009-06-10 13:38:08 +0200633 /* Then check for data tunneling */
Denys Vlasenkoa4bcbd02009-06-09 23:01:24 +0200634 ts = G.sessions;
Denis Vlasenko75f8d082006-11-22 15:54:52 +0000635 while (ts) { /* For all sessions... */
Denys Vlasenko1d77db82009-06-10 13:38:08 +0200636 struct tsession *next = ts->next; /* in case we free ts */
Eric Andersen08a72202002-09-30 20:52:10 +0000637
Denis Vlasenko59d7c432007-10-15 15:19:36 +0000638 if (/*ts->size1 &&*/ FD_ISSET(ts->ptyfd, &wrfdset)) {
Denis Vlasenko75f8d082006-11-22 15:54:52 +0000639 int num_totty;
Denis Vlasenko10916c52007-10-15 17:28:00 +0000640 unsigned char *ptr;
Denys Vlasenko1d77db82009-06-10 13:38:08 +0200641 /* Write to pty from buffer 1 */
Denis Vlasenko75f8d082006-11-22 15:54:52 +0000642 ptr = remove_iacs(ts, &num_totty);
Denis Vlasenko10916c52007-10-15 17:28:00 +0000643 count = safe_write(ts->ptyfd, ptr, num_totty);
644 if (count < 0) {
Denis Vlasenko59d7c432007-10-15 15:19:36 +0000645 if (errno == EAGAIN)
646 goto skip1;
Denis Vlasenkof472b232007-10-16 21:35:17 +0000647 goto kill_session;
Eric Andersen08a72202002-09-30 20:52:10 +0000648 }
Denis Vlasenko10916c52007-10-15 17:28:00 +0000649 ts->size1 -= count;
650 ts->wridx1 += count;
Denis Vlasenko59d7c432007-10-15 15:19:36 +0000651 if (ts->wridx1 >= BUFSIZE) /* actually == BUFSIZE */
Eric Andersen08a72202002-09-30 20:52:10 +0000652 ts->wridx1 = 0;
Eric Andersen08a72202002-09-30 20:52:10 +0000653 }
Denis Vlasenko59d7c432007-10-15 15:19:36 +0000654 skip1:
655 if (/*ts->size2 &&*/ FD_ISSET(ts->sockfd_write, &wrfdset)) {
Denys Vlasenko1d77db82009-06-10 13:38:08 +0200656 /* Write to socket from buffer 2 */
Denis Vlasenko10916c52007-10-15 17:28:00 +0000657 count = MIN(BUFSIZE - ts->wridx2, ts->size2);
Denys Vlasenkoa4bcbd02009-06-09 23:01:24 +0200658 count = iac_safe_write(ts->sockfd_write, (void*)(TS_BUF2(ts) + ts->wridx2), count);
Denis Vlasenko10916c52007-10-15 17:28:00 +0000659 if (count < 0) {
Denis Vlasenko59d7c432007-10-15 15:19:36 +0000660 if (errno == EAGAIN)
661 goto skip2;
Denis Vlasenkof472b232007-10-16 21:35:17 +0000662 goto kill_session;
Denis Vlasenko75f8d082006-11-22 15:54:52 +0000663 }
Denis Vlasenko10916c52007-10-15 17:28:00 +0000664 ts->size2 -= count;
665 ts->wridx2 += count;
Denis Vlasenko59d7c432007-10-15 15:19:36 +0000666 if (ts->wridx2 >= BUFSIZE) /* actually == BUFSIZE */
Denis Vlasenko75f8d082006-11-22 15:54:52 +0000667 ts->wridx2 = 0;
668 }
Denis Vlasenko59d7c432007-10-15 15:19:36 +0000669 skip2:
Denis Vlasenko10916c52007-10-15 17:28:00 +0000670 /* Should not be needed, but... remove_iacs is actually buggy
671 * (it cannot process iacs which wrap around buffer's end)!
672 * Since properly fixing it requires writing bigger code,
Denis Vlasenkof472b232007-10-16 21:35:17 +0000673 * we rely instead on this code making it virtually impossible
Denis Vlasenko10916c52007-10-15 17:28:00 +0000674 * to have wrapped iac (people don't type at 2k/second).
675 * It also allows for bigger reads in common case. */
Denis Vlasenko75f8d082006-11-22 15:54:52 +0000676 if (ts->size1 == 0) {
677 ts->rdidx1 = 0;
678 ts->wridx1 = 0;
679 }
680 if (ts->size2 == 0) {
681 ts->rdidx2 = 0;
682 ts->wridx2 = 0;
683 }
Denis Vlasenko10916c52007-10-15 17:28:00 +0000684
Denis Vlasenko59d7c432007-10-15 15:19:36 +0000685 if (/*ts->size1 < BUFSIZE &&*/ FD_ISSET(ts->sockfd_read, &rdfdset)) {
Denys Vlasenko1d77db82009-06-10 13:38:08 +0200686 /* Read from socket to buffer 1 */
Denis Vlasenko10916c52007-10-15 17:28:00 +0000687 count = MIN(BUFSIZE - ts->rdidx1, BUFSIZE - ts->size1);
Denys Vlasenkoa4bcbd02009-06-09 23:01:24 +0200688 count = safe_read(ts->sockfd_read, TS_BUF1(ts) + ts->rdidx1, count);
Denis Vlasenko10916c52007-10-15 17:28:00 +0000689 if (count <= 0) {
690 if (count < 0 && errno == EAGAIN)
Denis Vlasenko59d7c432007-10-15 15:19:36 +0000691 goto skip3;
Denis Vlasenkof472b232007-10-16 21:35:17 +0000692 goto kill_session;
Denis Vlasenko59d7c432007-10-15 15:19:36 +0000693 }
694 /* Ignore trailing NUL if it is there */
Denys Vlasenkoa4bcbd02009-06-09 23:01:24 +0200695 if (!TS_BUF1(ts)[ts->rdidx1 + count - 1]) {
Denis Vlasenkof472b232007-10-16 21:35:17 +0000696 --count;
Denis Vlasenko59d7c432007-10-15 15:19:36 +0000697 }
Denis Vlasenko10916c52007-10-15 17:28:00 +0000698 ts->size1 += count;
699 ts->rdidx1 += count;
Denis Vlasenko59d7c432007-10-15 15:19:36 +0000700 if (ts->rdidx1 >= BUFSIZE) /* actually == BUFSIZE */
701 ts->rdidx1 = 0;
702 }
703 skip3:
704 if (/*ts->size2 < BUFSIZE &&*/ FD_ISSET(ts->ptyfd, &rdfdset)) {
Denys Vlasenko1d77db82009-06-10 13:38:08 +0200705 /* Read from pty to buffer 2 */
Denis Vlasenko10916c52007-10-15 17:28:00 +0000706 count = MIN(BUFSIZE - ts->rdidx2, BUFSIZE - ts->size2);
Denys Vlasenkoa4bcbd02009-06-09 23:01:24 +0200707 count = safe_read(ts->ptyfd, TS_BUF2(ts) + ts->rdidx2, count);
Denis Vlasenko10916c52007-10-15 17:28:00 +0000708 if (count <= 0) {
709 if (count < 0 && errno == EAGAIN)
Denis Vlasenko59d7c432007-10-15 15:19:36 +0000710 goto skip4;
Denis Vlasenkof472b232007-10-16 21:35:17 +0000711 goto kill_session;
Denis Vlasenko59d7c432007-10-15 15:19:36 +0000712 }
Denis Vlasenko10916c52007-10-15 17:28:00 +0000713 ts->size2 += count;
714 ts->rdidx2 += count;
Denis Vlasenko59d7c432007-10-15 15:19:36 +0000715 if (ts->rdidx2 >= BUFSIZE) /* actually == BUFSIZE */
716 ts->rdidx2 = 0;
717 }
718 skip4:
Denis Vlasenko75f8d082006-11-22 15:54:52 +0000719 ts = next;
Denis Vlasenkof472b232007-10-16 21:35:17 +0000720 continue;
721 kill_session:
Denys Vlasenko3a416112010-04-05 22:10:38 +0200722 if (ts->shell_pid > 0)
723 update_utmp(ts->shell_pid, DEAD_PROCESS, /*tty_name:*/ NULL, /*username:*/ NULL, /*hostname:*/ NULL);
Denis Vlasenkof472b232007-10-16 21:35:17 +0000724 free_session(ts);
725 ts = next;
Denis Vlasenko75f8d082006-11-22 15:54:52 +0000726 }
Denis Vlasenkof472b232007-10-16 21:35:17 +0000727
Denis Vlasenko75f8d082006-11-22 15:54:52 +0000728 goto again;
Eric Andersen08a72202002-09-30 20:52:10 +0000729}