Contents of /tags/mkinitrd-6_1_4/busybox/networking/telnetd.c
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Wed Aug 5 16:25:39 2009 UTC (15 years, 1 month ago) by niro
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Wed Aug 5 16:25:39 2009 UTC (15 years, 1 month ago) by niro
File MIME type: text/plain
File size: 17621 byte(s)
tagged 'mkinitrd-6_1_4'
1 | /* vi: set sw=4 ts=4: */ |
2 | /* |
3 | * Simple telnet server |
4 | * Bjorn Wesen, Axis Communications AB (bjornw@axis.com) |
5 | * |
6 | * Licensed under GPLv2 or later, see file LICENSE in this tarball for details. |
7 | * |
8 | * --------------------------------------------------------------------------- |
9 | * (C) Copyright 2000, Axis Communications AB, LUND, SWEDEN |
10 | **************************************************************************** |
11 | * |
12 | * The telnetd manpage says it all: |
13 | * |
14 | * 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. |
19 | * |
20 | * Vladimir Oleynik <dzo@simtreas.ru> 2001 |
21 | * Set process group corrections, initial busybox port |
22 | */ |
23 | |
24 | #define DEBUG 0 |
25 | |
26 | #include "libbb.h" |
27 | #include <syslog.h> |
28 | |
29 | #if DEBUG |
30 | #define TELCMDS |
31 | #define TELOPTS |
32 | #endif |
33 | #include <arpa/telnet.h> |
34 | |
35 | /* Structure that describes a session */ |
36 | struct tsession { |
37 | struct tsession *next; |
38 | int sockfd_read, sockfd_write, ptyfd; |
39 | int shell_pid; |
40 | |
41 | /* two circular buffers */ |
42 | /*char *buf1, *buf2;*/ |
43 | /*#define TS_BUF1 ts->buf1*/ |
44 | /*#define TS_BUF2 TS_BUF2*/ |
45 | #define TS_BUF1 ((unsigned char*)(ts + 1)) |
46 | #define TS_BUF2 (((unsigned char*)(ts + 1)) + BUFSIZE) |
47 | int rdidx1, wridx1, size1; |
48 | int rdidx2, wridx2, size2; |
49 | }; |
50 | |
51 | /* Two buffers are directly after tsession in malloced memory. |
52 | * Make whole thing fit in 4k */ |
53 | enum { BUFSIZE = (4 * 1024 - sizeof(struct tsession)) / 2 }; |
54 | |
55 | |
56 | /* Globals */ |
57 | static int maxfd; |
58 | static struct tsession *sessions; |
59 | static const char *loginpath = "/bin/login"; |
60 | static const char *issuefile = "/etc/issue.net"; |
61 | |
62 | |
63 | /* |
64 | Remove all IAC's from buf1 (received IACs are ignored and must be removed |
65 | so as to not be interpreted by the terminal). Make an uninterrupted |
66 | string of characters fit for the terminal. Do this by packing |
67 | all characters meant for the terminal sequentially towards the end of buf. |
68 | |
69 | Return a pointer to the beginning of the characters meant for the terminal. |
70 | and make *num_totty the number of characters that should be sent to |
71 | the terminal. |
72 | |
73 | Note - If an IAC (3 byte quantity) starts before (bf + len) but extends |
74 | past (bf + len) then that IAC will be left unprocessed and *processed |
75 | will be less than len. |
76 | |
77 | FIXME - if we mean to send 0xFF to the terminal then it will be escaped, |
78 | what is the escape character? We aren't handling that situation here. |
79 | |
80 | CR-LF ->'s CR mapping is also done here, for convenience. |
81 | |
82 | NB: may fail to remove iacs which wrap around buffer! |
83 | */ |
84 | static unsigned char * |
85 | remove_iacs(struct tsession *ts, int *pnum_totty) |
86 | { |
87 | unsigned char *ptr0 = TS_BUF1 + ts->wridx1; |
88 | unsigned char *ptr = ptr0; |
89 | unsigned char *totty = ptr; |
90 | unsigned char *end = ptr + MIN(BUFSIZE - ts->wridx1, ts->size1); |
91 | int num_totty; |
92 | |
93 | while (ptr < end) { |
94 | if (*ptr != IAC) { |
95 | char c = *ptr; |
96 | |
97 | *totty++ = c; |
98 | ptr++; |
99 | /* We map \r\n ==> \r for pragmatic reasons. |
100 | * Many client implementations send \r\n when |
101 | * the user hits the CarriageReturn key. |
102 | */ |
103 | if (c == '\r' && ptr < end && (*ptr == '\n' || *ptr == '\0')) |
104 | ptr++; |
105 | continue; |
106 | } |
107 | |
108 | if ((ptr+1) >= end) |
109 | break; |
110 | if (ptr[1] == NOP) { /* Ignore? (putty keepalive, etc.) */ |
111 | ptr += 2; |
112 | continue; |
113 | } |
114 | if (ptr[1] == IAC) { /* Literal IAC? (emacs M-DEL) */ |
115 | *totty++ = ptr[1]; |
116 | ptr += 2; |
117 | continue; |
118 | } |
119 | |
120 | /* |
121 | * TELOPT_NAWS support! |
122 | */ |
123 | if ((ptr+2) >= end) { |
124 | /* only the beginning of the IAC is in the |
125 | buffer we were asked to process, we can't |
126 | process this char. */ |
127 | break; |
128 | } |
129 | /* |
130 | * IAC -> SB -> TELOPT_NAWS -> 4-byte -> IAC -> SE |
131 | */ |
132 | if (ptr[1] == SB && ptr[2] == TELOPT_NAWS) { |
133 | struct winsize ws; |
134 | if ((ptr+8) >= end) |
135 | break; /* incomplete, can't process */ |
136 | ws.ws_col = (ptr[3] << 8) | ptr[4]; |
137 | ws.ws_row = (ptr[5] << 8) | ptr[6]; |
138 | ioctl(ts->ptyfd, TIOCSWINSZ, (char *)&ws); |
139 | ptr += 9; |
140 | continue; |
141 | } |
142 | /* skip 3-byte IAC non-SB cmd */ |
143 | #if DEBUG |
144 | fprintf(stderr, "Ignoring IAC %s,%s\n", |
145 | TELCMD(ptr[1]), TELOPT(ptr[2])); |
146 | #endif |
147 | ptr += 3; |
148 | } |
149 | |
150 | num_totty = totty - ptr0; |
151 | *pnum_totty = num_totty; |
152 | /* the difference between ptr and totty is number of iacs |
153 | we removed from the stream. Adjust buf1 accordingly. */ |
154 | if ((ptr - totty) == 0) /* 99.999% of cases */ |
155 | return ptr0; |
156 | ts->wridx1 += ptr - totty; |
157 | ts->size1 -= ptr - totty; |
158 | /* move chars meant for the terminal towards the end of the buffer */ |
159 | return memmove(ptr - num_totty, ptr0, num_totty); |
160 | } |
161 | |
162 | |
163 | static struct tsession * |
164 | make_new_session( |
165 | USE_FEATURE_TELNETD_STANDALONE(int sock) |
166 | SKIP_FEATURE_TELNETD_STANDALONE(void) |
167 | ) { |
168 | const char *login_argv[2]; |
169 | struct termios termbuf; |
170 | int fd, pid; |
171 | char tty_name[GETPTY_BUFSIZE]; |
172 | struct tsession *ts = xzalloc(sizeof(struct tsession) + BUFSIZE * 2); |
173 | |
174 | /*ts->buf1 = (char *)(ts + 1);*/ |
175 | /*ts->buf2 = ts->buf1 + BUFSIZE;*/ |
176 | |
177 | /* Got a new connection, set up a tty. */ |
178 | fd = xgetpty(tty_name); |
179 | if (fd > maxfd) |
180 | maxfd = fd; |
181 | ts->ptyfd = fd; |
182 | ndelay_on(fd); |
183 | #if ENABLE_FEATURE_TELNETD_STANDALONE |
184 | ts->sockfd_read = sock; |
185 | /* SO_KEEPALIVE by popular demand */ |
186 | setsockopt(sock, SOL_SOCKET, SO_KEEPALIVE, &const_int_1, sizeof(const_int_1)); |
187 | ndelay_on(sock); |
188 | if (!sock) { /* We are called with fd 0 - we are in inetd mode */ |
189 | sock++; /* so use fd 1 for output */ |
190 | ndelay_on(sock); |
191 | } |
192 | ts->sockfd_write = sock; |
193 | if (sock > maxfd) |
194 | maxfd = sock; |
195 | #else |
196 | /* SO_KEEPALIVE by popular demand */ |
197 | setsockopt(0, SOL_SOCKET, SO_KEEPALIVE, &const_int_1, sizeof(const_int_1)); |
198 | /* ts->sockfd_read = 0; - done by xzalloc */ |
199 | ts->sockfd_write = 1; |
200 | ndelay_on(0); |
201 | ndelay_on(1); |
202 | #endif |
203 | /* Make the telnet client understand we will echo characters so it |
204 | * should not do it locally. We don't tell the client to run linemode, |
205 | * because we want to handle line editing and tab completion and other |
206 | * stuff that requires char-by-char support. */ |
207 | { |
208 | static const char iacs_to_send[] ALIGN1 = { |
209 | IAC, DO, TELOPT_ECHO, |
210 | IAC, DO, TELOPT_NAWS, |
211 | IAC, DO, TELOPT_LFLOW, |
212 | IAC, WILL, TELOPT_ECHO, |
213 | IAC, WILL, TELOPT_SGA |
214 | }; |
215 | memcpy(TS_BUF2, iacs_to_send, sizeof(iacs_to_send)); |
216 | ts->rdidx2 = sizeof(iacs_to_send); |
217 | ts->size2 = sizeof(iacs_to_send); |
218 | } |
219 | |
220 | fflush(NULL); /* flush all streams */ |
221 | pid = vfork(); /* NOMMU-friendly */ |
222 | if (pid < 0) { |
223 | free(ts); |
224 | close(fd); |
225 | /* sock will be closed by caller */ |
226 | bb_perror_msg("vfork"); |
227 | return NULL; |
228 | } |
229 | if (pid > 0) { |
230 | /* Parent */ |
231 | ts->shell_pid = pid; |
232 | return ts; |
233 | } |
234 | |
235 | /* Child */ |
236 | /* Careful - we are after vfork! */ |
237 | |
238 | /* make new session and process group */ |
239 | setsid(); |
240 | |
241 | /* Restore default signal handling */ |
242 | bb_signals((1 << SIGCHLD) + (1 << SIGPIPE), SIG_DFL); |
243 | |
244 | /* open the child's side of the tty. */ |
245 | /* NB: setsid() disconnects from any previous ctty's. Therefore |
246 | * we must open child's side of the tty AFTER setsid! */ |
247 | close(0); |
248 | xopen(tty_name, O_RDWR); /* becomes our ctty */ |
249 | xdup2(0, 1); |
250 | xdup2(0, 2); |
251 | tcsetpgrp(0, getpid()); /* switch this tty's process group to us */ |
252 | |
253 | /* The pseudo-terminal allocated to the client is configured to operate in |
254 | * cooked mode, and with XTABS CRMOD enabled (see tty(4)). */ |
255 | tcgetattr(0, &termbuf); |
256 | termbuf.c_lflag |= ECHO; /* if we use readline we dont want this */ |
257 | termbuf.c_oflag |= ONLCR | XTABS; |
258 | termbuf.c_iflag |= ICRNL; |
259 | termbuf.c_iflag &= ~IXOFF; |
260 | /*termbuf.c_lflag &= ~ICANON;*/ |
261 | tcsetattr_stdin_TCSANOW(&termbuf); |
262 | |
263 | /* Uses FILE-based I/O to stdout, but does fflush(stdout), |
264 | * so should be safe with vfork. |
265 | * I fear, though, that some users will have ridiculously big |
266 | * issue files, and they may block writing to fd 1, |
267 | * (parent is supposed to read it, but parent waits |
268 | * for vforked child to exec!) */ |
269 | print_login_issue(issuefile, tty_name); |
270 | |
271 | /* Exec shell / login / whatever */ |
272 | login_argv[0] = loginpath; |
273 | login_argv[1] = NULL; |
274 | /* exec busybox applet (if PREFER_APPLETS=y), if that fails, |
275 | * exec external program */ |
276 | BB_EXECVP(loginpath, (char **)login_argv); |
277 | /* _exit is safer with vfork, and we shouldn't send message |
278 | * to remote clients anyway */ |
279 | _exit(EXIT_FAILURE); /*bb_perror_msg_and_die("execv %s", loginpath);*/ |
280 | } |
281 | |
282 | /* Must match getopt32 string */ |
283 | enum { |
284 | OPT_WATCHCHILD = (1 << 2), /* -K */ |
285 | OPT_INETD = (1 << 3) * ENABLE_FEATURE_TELNETD_STANDALONE, /* -i */ |
286 | OPT_PORT = (1 << 4) * ENABLE_FEATURE_TELNETD_STANDALONE, /* -p */ |
287 | OPT_FOREGROUND = (1 << 6) * ENABLE_FEATURE_TELNETD_STANDALONE, /* -F */ |
288 | }; |
289 | |
290 | #if ENABLE_FEATURE_TELNETD_STANDALONE |
291 | |
292 | static void |
293 | free_session(struct tsession *ts) |
294 | { |
295 | struct tsession *t = sessions; |
296 | |
297 | if (option_mask32 & OPT_INETD) |
298 | exit(EXIT_SUCCESS); |
299 | |
300 | /* Unlink this telnet session from the session list */ |
301 | if (t == ts) |
302 | sessions = ts->next; |
303 | else { |
304 | while (t->next != ts) |
305 | t = t->next; |
306 | t->next = ts->next; |
307 | } |
308 | |
309 | #if 0 |
310 | /* It was said that "normal" telnetd just closes ptyfd, |
311 | * doesn't send SIGKILL. When we close ptyfd, |
312 | * kernel sends SIGHUP to processes having slave side opened. */ |
313 | kill(ts->shell_pid, SIGKILL); |
314 | wait4(ts->shell_pid, NULL, 0, NULL); |
315 | #endif |
316 | close(ts->ptyfd); |
317 | close(ts->sockfd_read); |
318 | /* We do not need to close(ts->sockfd_write), it's the same |
319 | * as sockfd_read unless we are in inetd mode. But in inetd mode |
320 | * we do not reach this */ |
321 | free(ts); |
322 | |
323 | /* Scan all sessions and find new maxfd */ |
324 | maxfd = 0; |
325 | ts = sessions; |
326 | while (ts) { |
327 | if (maxfd < ts->ptyfd) |
328 | maxfd = ts->ptyfd; |
329 | if (maxfd < ts->sockfd_read) |
330 | maxfd = ts->sockfd_read; |
331 | #if 0 |
332 | /* Again, sockfd_write == sockfd_read here */ |
333 | if (maxfd < ts->sockfd_write) |
334 | maxfd = ts->sockfd_write; |
335 | #endif |
336 | ts = ts->next; |
337 | } |
338 | } |
339 | |
340 | #else /* !FEATURE_TELNETD_STANDALONE */ |
341 | |
342 | /* Used in main() only, thus "return 0" actually is exit(EXIT_SUCCESS). */ |
343 | #define free_session(ts) return 0 |
344 | |
345 | #endif |
346 | |
347 | static void handle_sigchld(int sig UNUSED_PARAM) |
348 | { |
349 | pid_t pid; |
350 | struct tsession *ts; |
351 | |
352 | /* Looping: more than one child may have exited */ |
353 | while (1) { |
354 | pid = wait_any_nohang(NULL); |
355 | if (pid <= 0) |
356 | break; |
357 | ts = sessions; |
358 | while (ts) { |
359 | if (ts->shell_pid == pid) { |
360 | ts->shell_pid = -1; |
361 | break; |
362 | } |
363 | ts = ts->next; |
364 | } |
365 | } |
366 | } |
367 | |
368 | int telnetd_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; |
369 | int telnetd_main(int argc UNUSED_PARAM, char **argv) |
370 | { |
371 | fd_set rdfdset, wrfdset; |
372 | unsigned opt; |
373 | int count; |
374 | struct tsession *ts; |
375 | #if ENABLE_FEATURE_TELNETD_STANDALONE |
376 | #define IS_INETD (opt & OPT_INETD) |
377 | int master_fd = master_fd; /* be happy, gcc */ |
378 | unsigned portnbr = 23; |
379 | char *opt_bindaddr = NULL; |
380 | char *opt_portnbr; |
381 | #else |
382 | enum { |
383 | IS_INETD = 1, |
384 | master_fd = -1, |
385 | portnbr = 23, |
386 | }; |
387 | #endif |
388 | /* Even if !STANDALONE, we accept (and ignore) -i, thus people |
389 | * don't need to guess whether it's ok to pass -i to us */ |
390 | opt = getopt32(argv, "f:l:Ki" USE_FEATURE_TELNETD_STANDALONE("p:b:F"), |
391 | &issuefile, &loginpath |
392 | USE_FEATURE_TELNETD_STANDALONE(, &opt_portnbr, &opt_bindaddr)); |
393 | if (!IS_INETD /*&& !re_execed*/) { |
394 | /* inform that we start in standalone mode? |
395 | * May be useful when people forget to give -i */ |
396 | /*bb_error_msg("listening for connections");*/ |
397 | if (!(opt & OPT_FOREGROUND)) { |
398 | /* DAEMON_CHDIR_ROOT was giving inconsistent |
399 | * behavior with/without -F, -i */ |
400 | bb_daemonize_or_rexec(0 /*was DAEMON_CHDIR_ROOT*/, argv); |
401 | } |
402 | } |
403 | /* Redirect log to syslog early, if needed */ |
404 | if (IS_INETD || !(opt & OPT_FOREGROUND)) { |
405 | openlog(applet_name, 0, LOG_USER); |
406 | logmode = LOGMODE_SYSLOG; |
407 | } |
408 | USE_FEATURE_TELNETD_STANDALONE( |
409 | if (opt & OPT_PORT) |
410 | portnbr = xatou16(opt_portnbr); |
411 | ); |
412 | |
413 | /* Used to check access(loginpath, X_OK) here. Pointless. |
414 | * exec will do this for us for free later. */ |
415 | |
416 | #if ENABLE_FEATURE_TELNETD_STANDALONE |
417 | if (IS_INETD) { |
418 | sessions = make_new_session(0); |
419 | if (!sessions) /* pty opening or vfork problem, exit */ |
420 | return 1; /* make_new_session prints error message */ |
421 | } else { |
422 | master_fd = create_and_bind_stream_or_die(opt_bindaddr, portnbr); |
423 | xlisten(master_fd, 1); |
424 | } |
425 | #else |
426 | sessions = make_new_session(); |
427 | if (!sessions) /* pty opening or vfork problem, exit */ |
428 | return 1; /* make_new_session prints error message */ |
429 | #endif |
430 | |
431 | /* We don't want to die if just one session is broken */ |
432 | signal(SIGPIPE, SIG_IGN); |
433 | |
434 | if (opt & OPT_WATCHCHILD) |
435 | signal(SIGCHLD, handle_sigchld); |
436 | else /* prevent dead children from becoming zombies */ |
437 | signal(SIGCHLD, SIG_IGN); |
438 | |
439 | /* |
440 | This is how the buffers are used. The arrows indicate the movement |
441 | of data. |
442 | +-------+ wridx1++ +------+ rdidx1++ +----------+ |
443 | | | <-------------- | buf1 | <-------------- | | |
444 | | | size1-- +------+ size1++ | | |
445 | | pty | | socket | |
446 | | | rdidx2++ +------+ wridx2++ | | |
447 | | | --------------> | buf2 | --------------> | | |
448 | +-------+ size2++ +------+ size2-- +----------+ |
449 | |
450 | size1: "how many bytes are buffered for pty between rdidx1 and wridx1?" |
451 | size2: "how many bytes are buffered for socket between rdidx2 and wridx2?" |
452 | |
453 | Each session has got two buffers. Buffers are circular. If sizeN == 0, |
454 | buffer is empty. If sizeN == BUFSIZE, buffer is full. In both these cases |
455 | rdidxN == wridxN. |
456 | */ |
457 | again: |
458 | FD_ZERO(&rdfdset); |
459 | FD_ZERO(&wrfdset); |
460 | |
461 | /* Select on the master socket, all telnet sockets and their |
462 | * ptys if there is room in their session buffers. |
463 | * NB: scalability problem: we recalculate entire bitmap |
464 | * before each select. Can be a problem with 500+ connections. */ |
465 | ts = sessions; |
466 | while (ts) { |
467 | struct tsession *next = ts->next; /* in case we free ts. */ |
468 | if (ts->shell_pid == -1) { |
469 | /* Child died and we detected that */ |
470 | free_session(ts); |
471 | } else { |
472 | if (ts->size1 > 0) /* can write to pty */ |
473 | FD_SET(ts->ptyfd, &wrfdset); |
474 | if (ts->size1 < BUFSIZE) /* can read from socket */ |
475 | FD_SET(ts->sockfd_read, &rdfdset); |
476 | if (ts->size2 > 0) /* can write to socket */ |
477 | FD_SET(ts->sockfd_write, &wrfdset); |
478 | if (ts->size2 < BUFSIZE) /* can read from pty */ |
479 | FD_SET(ts->ptyfd, &rdfdset); |
480 | } |
481 | ts = next; |
482 | } |
483 | if (!IS_INETD) { |
484 | FD_SET(master_fd, &rdfdset); |
485 | /* This is needed because free_session() does not |
486 | * take master_fd into account when it finds new |
487 | * maxfd among remaining fd's */ |
488 | if (master_fd > maxfd) |
489 | maxfd = master_fd; |
490 | } |
491 | |
492 | count = select(maxfd + 1, &rdfdset, &wrfdset, NULL, NULL); |
493 | if (count < 0) |
494 | goto again; /* EINTR or ENOMEM */ |
495 | |
496 | #if ENABLE_FEATURE_TELNETD_STANDALONE |
497 | /* First check for and accept new sessions. */ |
498 | if (!IS_INETD && FD_ISSET(master_fd, &rdfdset)) { |
499 | int fd; |
500 | struct tsession *new_ts; |
501 | |
502 | fd = accept(master_fd, NULL, NULL); |
503 | if (fd < 0) |
504 | goto again; |
505 | /* Create a new session and link it into our active list */ |
506 | new_ts = make_new_session(fd); |
507 | if (new_ts) { |
508 | new_ts->next = sessions; |
509 | sessions = new_ts; |
510 | } else { |
511 | close(fd); |
512 | } |
513 | } |
514 | #endif |
515 | |
516 | /* Then check for data tunneling. */ |
517 | ts = sessions; |
518 | while (ts) { /* For all sessions... */ |
519 | struct tsession *next = ts->next; /* in case we free ts. */ |
520 | |
521 | if (/*ts->size1 &&*/ FD_ISSET(ts->ptyfd, &wrfdset)) { |
522 | int num_totty; |
523 | unsigned char *ptr; |
524 | /* Write to pty from buffer 1. */ |
525 | ptr = remove_iacs(ts, &num_totty); |
526 | count = safe_write(ts->ptyfd, ptr, num_totty); |
527 | if (count < 0) { |
528 | if (errno == EAGAIN) |
529 | goto skip1; |
530 | goto kill_session; |
531 | } |
532 | ts->size1 -= count; |
533 | ts->wridx1 += count; |
534 | if (ts->wridx1 >= BUFSIZE) /* actually == BUFSIZE */ |
535 | ts->wridx1 = 0; |
536 | } |
537 | skip1: |
538 | if (/*ts->size2 &&*/ FD_ISSET(ts->sockfd_write, &wrfdset)) { |
539 | /* Write to socket from buffer 2. */ |
540 | count = MIN(BUFSIZE - ts->wridx2, ts->size2); |
541 | count = safe_write(ts->sockfd_write, TS_BUF2 + ts->wridx2, count); |
542 | if (count < 0) { |
543 | if (errno == EAGAIN) |
544 | goto skip2; |
545 | goto kill_session; |
546 | } |
547 | ts->size2 -= count; |
548 | ts->wridx2 += count; |
549 | if (ts->wridx2 >= BUFSIZE) /* actually == BUFSIZE */ |
550 | ts->wridx2 = 0; |
551 | } |
552 | skip2: |
553 | /* Should not be needed, but... remove_iacs is actually buggy |
554 | * (it cannot process iacs which wrap around buffer's end)! |
555 | * Since properly fixing it requires writing bigger code, |
556 | * we rely instead on this code making it virtually impossible |
557 | * to have wrapped iac (people don't type at 2k/second). |
558 | * It also allows for bigger reads in common case. */ |
559 | if (ts->size1 == 0) { |
560 | ts->rdidx1 = 0; |
561 | ts->wridx1 = 0; |
562 | } |
563 | if (ts->size2 == 0) { |
564 | ts->rdidx2 = 0; |
565 | ts->wridx2 = 0; |
566 | } |
567 | |
568 | if (/*ts->size1 < BUFSIZE &&*/ FD_ISSET(ts->sockfd_read, &rdfdset)) { |
569 | /* Read from socket to buffer 1. */ |
570 | count = MIN(BUFSIZE - ts->rdidx1, BUFSIZE - ts->size1); |
571 | count = safe_read(ts->sockfd_read, TS_BUF1 + ts->rdidx1, count); |
572 | if (count <= 0) { |
573 | if (count < 0 && errno == EAGAIN) |
574 | goto skip3; |
575 | goto kill_session; |
576 | } |
577 | /* Ignore trailing NUL if it is there */ |
578 | if (!TS_BUF1[ts->rdidx1 + count - 1]) { |
579 | --count; |
580 | } |
581 | ts->size1 += count; |
582 | ts->rdidx1 += count; |
583 | if (ts->rdidx1 >= BUFSIZE) /* actually == BUFSIZE */ |
584 | ts->rdidx1 = 0; |
585 | } |
586 | skip3: |
587 | if (/*ts->size2 < BUFSIZE &&*/ FD_ISSET(ts->ptyfd, &rdfdset)) { |
588 | /* Read from pty to buffer 2. */ |
589 | count = MIN(BUFSIZE - ts->rdidx2, BUFSIZE - ts->size2); |
590 | count = safe_read(ts->ptyfd, TS_BUF2 + ts->rdidx2, count); |
591 | if (count <= 0) { |
592 | if (count < 0 && errno == EAGAIN) |
593 | goto skip4; |
594 | goto kill_session; |
595 | } |
596 | ts->size2 += count; |
597 | ts->rdidx2 += count; |
598 | if (ts->rdidx2 >= BUFSIZE) /* actually == BUFSIZE */ |
599 | ts->rdidx2 = 0; |
600 | } |
601 | skip4: |
602 | ts = next; |
603 | continue; |
604 | kill_session: |
605 | free_session(ts); |
606 | ts = next; |
607 | } |
608 | |
609 | goto again; |
610 | } |