aboutsummaryrefslogblamecommitdiffstats
path: root/erts/etc/unix/to_erl.c
blob: 588d127445208c28d87ebd18c392153c9eb0ef5c (plain) (tree)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610

































































































































































































































































































































































































































































































































































































































                                                                                                    
/*
 * %CopyrightBegin%
 * 
 * Copyright Ericsson AB 1996-2009. All Rights Reserved.
 * 
 * The contents of this file are subject to the Erlang Public License,
 * Version 1.1, (the "License"); you may not use this file except in
 * compliance with the License. You should have received a copy of the
 * Erlang Public License along with this software. If not, it can be
 * retrieved online at http://www.erlang.org/.
 * 
 * Software distributed under the License is distributed on an "AS IS"
 * basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
 * the License for the specific language governing rights and limitations
 * under the License.
 * 
 * %CopyrightEnd%
 */
/* 
 * Module: to_erl.c
 * 
 * This module implements a process that opens two specified FIFOs, one
 * for reading and one for writing; reads from its stdin, and writes what
 * it has read to the write FIF0; reads from the read FIFO, and writes to
 * its stdout.
 *
  ________                            _________ 
 |        |--<-- pipe.r (fifo1) --<--|         |
 | to_erl |                          | run_erl | (parent)
 |________|-->-- pipe.w (fifo2) -->--|_________|
                                          ^ master pty
                                          |
                                          | slave pty
                                      ____V____ 
                                     |         |
                                     |  "erl"  | (child)
                                     |_________|
 */
#ifdef HAVE_CONFIG_H
#  include "config.h"
#endif

#include <sys/types.h>
#include <sys/stat.h>
#include <sys/time.h>
#include <sys/types.h>
#include <fcntl.h>
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <termios.h>
#include <dirent.h>
#include <signal.h>
#include <errno.h>
#ifdef HAVE_SYS_IOCTL_H
#  include <sys/ioctl.h>
#endif

#include "run_erl.h"
#include "safe_string.h"   /* strn_cpy, strn_catf, sn_printf, etc. */

#if defined(O_NONBLOCK)
# define DONT_BLOCK_PLEASE O_NONBLOCK
#else
# define DONT_BLOCK_PLEASE O_NDELAY
# if !defined(EAGAIN)
#  define EAGAIN -3898734
# endif
#endif

#ifdef HAVE_STRERROR
#  define STRERROR(x) strerror(x)
#else
#  define STRERROR(x) ""
#endif

#define noDEBUG

#define PIPE_DIR        "/tmp/"
#define PIPE_STUBNAME   "erlang.pipe"
#define PIPE_STUBLEN    strlen(PIPE_STUBNAME)

#ifdef DEBUG
#define STATUS(s)  { fprintf(stderr, (s)); fflush(stderr); }
#else
#define STATUS(s)
#endif

#ifndef FILENAME_MAX
#define FILENAME_MAX 250
#endif

static struct termios tty_smode, tty_rmode;
static int tty_eof = 0;
static int recv_sig = 0;
static int protocol_ver = RUN_ERL_LO_VER; /* assume lowest to begin with */

static int write_all(int fd, const char* buf, int len);
static int window_size_seq(char* buf, size_t bufsz);
static int version_handshake(char* buf, int len, int wfd);
#ifdef DEBUG
static void show_terminal_settings(struct termios *);
#endif

static void handle_ctrlc(int sig)
{
    /* Reinstall the handler, and signal break flag */
    signal(SIGINT,handle_ctrlc);
    recv_sig = SIGINT;
}  

static void handle_sigwinch(int sig)
{
    recv_sig = SIGWINCH;
}

static void usage(char *pname)
{
    fprintf(stderr, "Usage: %s [-h|-F] [pipe_name|pipe_dir/]\n", pname);
    fprintf(stderr, "\t-h\tThis help text.\n");
    fprintf(stderr, "\t-F\tForce connection even though pipe is locked by other to_erl process.\n");
}

int main(int argc, char **argv)
{
    char  FIFO1[FILENAME_MAX], FIFO2[FILENAME_MAX];
    int i, len, wfd, rfd, result = 0;
    fd_set readfds;
    char buf[BUFSIZ];
    char pipename[FILENAME_MAX];
    int pipeIx = 1;
    int force_lock = 0;
    int got_some = 0;

    if (argc >= 2 && argv[1][0]=='-') {
	switch (argv[1][1]) {
	case 'h':
	    usage(argv[0]);
	    exit(1);
	case 'F':
	    force_lock = 1;
	    break;
	default:
	    fprintf(stderr,"Invalid option '%s'\n",argv[1]);
	    exit(1);
	}
	pipeIx = 2;
    }
    
#ifdef DEBUG
    fprintf(stderr, "%s: pid is : %d\n", argv[0], (int)getpid());
#endif
    
    strn_cpy(pipename, sizeof(pipename),
	     (argv[pipeIx] ? argv[pipeIx] : PIPE_DIR));
    
    if(*pipename && pipename[strlen(pipename)-1] == '/') {
	/* The user wishes us to find a pipe name in the specified */
	/* directory */
	int highest_pipe_num = 0;
	DIR *dirp;
	struct dirent *direntp;

	dirp = opendir(pipename);
	if(!dirp) {
	    fprintf(stderr, "Can't access pipe directory %s.\n", pipename);
	    exit(1);
	}

	/* Check the directory for existing pipes */
    
	while((direntp=readdir(dirp)) != NULL) {
	    if(strncmp(direntp->d_name,PIPE_STUBNAME,PIPE_STUBLEN)==0) {
		int num = atoi(direntp->d_name+PIPE_STUBLEN+1);
		if(num > highest_pipe_num)
		    highest_pipe_num = num;
	    }
	}	
	closedir(dirp);
	strn_catf(pipename, sizeof(pipename), (highest_pipe_num?"%s.%d":"%s"),
		  PIPE_STUBNAME, highest_pipe_num);
    } /* if */

    /* read FIFO */
    sn_printf(FIFO1,sizeof(FIFO1),"%s.r",pipename);
    /* write FIFO */
    sn_printf(FIFO2,sizeof(FIFO2),"%s.w",pipename);

    /* Check that nobody is running to_erl on this pipe already */
    if ((wfd = open (FIFO1, O_WRONLY|DONT_BLOCK_PLEASE, 0)) >= 0) {
	/* Open as server succeeded -- to_erl is already running! */
	close(wfd);
	fprintf(stderr, "Another to_erl process already attached to pipe "
			"%s.\n", pipename);
	if (force_lock) {
	    fprintf(stderr, "But we proceed anyway by force (-F).\n");
	} 
	else {
	    exit(1);
	}
    }

    if ((rfd = open (FIFO1, O_RDONLY|DONT_BLOCK_PLEASE, 0)) < 0) {
#ifdef DEBUG
	fprintf(stderr, "Could not open FIFO %s for reading.\n", FIFO1);
#endif
	fprintf(stderr, "No running Erlang on pipe %s.\n", pipename);
	exit(1);
    }
#ifdef DEBUG
    fprintf(stderr, "to_erl: %s opened for reading\n", FIFO1);
#endif
    
    if ((wfd = open (FIFO2, O_WRONLY|DONT_BLOCK_PLEASE, 0)) < 0) {
#ifdef DEBUG
	fprintf(stderr, "Could not open FIFO %s for writing.\n", FIFO2);
#endif
	fprintf(stderr, "No running Erlang on pipe %s.\n", pipename);
	close(rfd);
	exit(1);
    }
#ifdef DEBUG
    fprintf(stderr, "to_erl: %s opened for writing\n", FIFO2);
#endif
    
    fprintf(stderr, "Attaching to %s (^D to exit)\n\n", pipename);
    
    /* Set break handler to our handler */
    signal(SIGINT,handle_ctrlc);

    /* 
     * Save the current state of the terminal, and set raw mode.
     */
    if (tcgetattr(0, &tty_rmode) , 0) {
	fprintf(stderr, "Cannot get terminals current mode\n");
	exit(-1);
    }
    tty_smode = tty_rmode;
    tty_eof = '\004'; /* Ctrl+D to exit */
#ifdef DEBUG
    show_terminal_settings(&tty_rmode);
#endif
    tty_smode.c_iflag =
	1*BRKINT |/*Signal interrupt on break.*/
	    1*IGNPAR |/*Ignore characters with parity errors.*/
		1*ISTRIP |/*Strip character.*/
		    0;
    
#if 0
0*IGNBRK |/*Ignore break condition.*/
0*PARMRK |/*Mark parity errors.*/
0*INPCK  |/*Enable input parity check.*/
0*INLCR  |/*Map NL to CR on input.*/
0*IGNCR  |/*Ignore CR.*/
0*ICRNL  |/*Map CR to NL on input.*/
0*IUCLC  |/*Map upper-case to lower-case on input.*/
0*IXON   |/*Enable start/stop output control.*/
0*IXANY  |/*Enable any character to restart output.*/
0*IXOFF  |/*Enable start/stop input control.*/
0*IMAXBEL|/*Echo BEL on input line too long.*/
#endif
						
    tty_smode.c_oflag =
	1*OPOST  |/*Post-process output.*/
	    1*ONLCR  |/*Map NL to CR-NL on output.*/
#ifdef XTABS
		1*XTABS  |/*Expand tabs to spaces. (Linux)*/
#endif
#ifdef OXTABS
		    1*OXTABS  |/*Expand tabs to spaces. (FreeBSD)*/
#endif
#ifdef NL0
			1*NL0    |/*Select newline delays*/
#endif
#ifdef CR0
			    1*CR0    |/*Select carriage-return delays*/
#endif
#ifdef TAB0
				1*TAB0   |/*Select horizontal tab delays*/
#endif
#ifdef BS0
				    1*BS0    |/*Select backspace delays*/
#endif
#ifdef VT0
					1*VT0    |/*Select vertical tab delays*/
#endif
#ifdef FF0
					    1*FF0    |/*Select form feed delays*/
#endif
											    0;
    
#if 0
0*OLCUC  |/*Map lower case to upper on output.*/
0*OCRNL  |/*Map CR to NL on output.*/
0*ONOCR  |/*No CR output at column 0.*/
0*ONLRET |/*NL performs CR function.*/
0*OFILL  |/*Use fill characters for delay.*/
0*OFDEL  |/*Fill is DEL, else NULL.*/
0*NL1    |
0*CR1    |
0*CR2    |
0*CR3    |
0*TAB1   |
0*TAB2   |
0*TAB3   |/*Expand tabs to spaces.*/
0*BS1    |
0*VT1    |
0*FF1    |
#endif
								    
    /* JALI: removed setting the tty_smode.c_cflag flags, since this is not */
    /* advisable if this is a *real* terminal, such as the console. In fact */
    /* this may hang the entire machine, deep, deep down (signalling break */
    /* or toggling the abort switch doesn't help) */
    
    tty_smode.c_lflag =
									0;
    
#if 0
0*ISIG   |/*Enable signals.*/
0*ICANON |/*Canonical input (erase and kill processing).*/
0*XCASE  |/*Canonical upper/lower presentation.*/
0*ECHO   |/*Enable echo.*/
0*ECHOE  |/*Echo erase character as BS-SP-BS.*/
0*ECHOK  |/*Echo NL after kill character.*/
0*ECHONL |/*Echo NL.*/
0*NOFLSH |/*Disable flush after interrupt or quit.*/
0*TOSTOP |/*Send SIGTTOU for background output.*/
0*ECHOCTL|/*Echo control characters as ^char, delete as ^?.*/
0*ECHOPRT|/*Echo erase character as character erased.*/
0*ECHOKE |/*BS-SP-BS erase entire line on line kill.*/
0*FLUSHO |/*Output is being flushed.*/
0*PENDIN |/*Retype pending input at next read or input character.*/
0*IEXTEN |/*Enable extended (implementation-defined) functions.*/
#endif
								
    tty_smode.c_cc[VMIN]      =0;/* Note that VMIN is the same as VEOF! */
    tty_smode.c_cc[VTIME]     =0;/* Note that VTIME is the same as VEOL! */
    tty_smode.c_cc[VINTR]     =3;
    
    tcsetattr(0, TCSANOW, &tty_smode);
    
#ifdef DEBUG
    show_terminal_settings(&tty_smode);
#endif
    /*
     * 	 "Write a ^R to the FIFO which causes the other end to redisplay
     *    the input line."
     * This does not seem to work as was intended in old comment above.
     * However, this control character is now (R12B-3) used by run_erl
     * to trigger the version handshaking between to_erl and run_erl
     * at the start of every new to_erl-session.
     */
    write(wfd, "\022", 1);

    /*
     * read and write
     */
    while (1) {
	FD_ZERO(&readfds);
	FD_SET(0, &readfds);
	FD_SET(rfd, &readfds);
	if (select(rfd + 1, &readfds, NULL, NULL, NULL) < 0) {
	    if (recv_sig) {
		FD_ZERO(&readfds);
	    }
	    else {
		fprintf(stderr, "Error in select.\n");
		result = -1;
		break;
	    }
	}
	len = 0;

	/*
	 * Read from terminal and write to FIFO
         */
	if (recv_sig) {
	    switch (recv_sig) {
	    case SIGINT:
		fprintf(stderr, "[Break]\n\r");
		buf[0] = '\003';
		len = 1;
		break;
	    case SIGWINCH:
		len = window_size_seq(buf,sizeof(buf));
		break;
	    default:
		fprintf(stderr,"Unexpected signal: %u\n",recv_sig);
	    }
	    recv_sig = 0;
	}
	else if (FD_ISSET(0, &readfds)) {
	    len = read(0, buf, sizeof(buf));
	    if (len <= 0) {
		close(rfd);
		close(wfd);
		if (len < 0) {
		    fprintf(stderr, "Error in reading from stdin.\n");
		    result = -1;
		} else {
		    fprintf(stderr, "[EOF]\n\r");
		}
		break;
	    }
	    /* check if there is an eof character in input */
	    for (i = 0; i < len && buf[i] != tty_eof; i++);
	    if (buf[i] == tty_eof) {
		fprintf(stderr, "[Quit]\n\r");
		break;
	    }
	}

	if (len) {
#ifdef DEBUG
	    write(1, buf, len);
#endif
	    if (write_all(wfd, buf, len) != len) {
		fprintf(stderr, "Error in writing to FIFO.\n");
		close(rfd);
		close(wfd);
		result = -1;
		break;
	    }
	    STATUS("\" OK\r\n");
	}

	/*
	 * Read from FIFO, write to terminal.
	 */
	if (FD_ISSET(rfd, &readfds)) {
	    STATUS("FIFO read: ");
	    len = read(rfd, buf, BUFSIZ);
	    if (len < 0 && errno == EAGAIN) {
		/*
		 * No data this time, but the writing end of the FIFO is still open.
		 * Do nothing.
		 */
		;
	    } else if (len <= 0) {
		/*
		 * Either an error or end of file. In either case, break out
		 * of the loop.
		 */
		close(rfd);
		close(wfd);
		if (len < 0) {
		    fprintf(stderr, "Error in reading from FIFO.\n");
		    result = -1;
		} else
		    fprintf(stderr, "[End]\n\r");
		break;
	    } else {
		if (!got_some) {
		    if ((len=version_handshake(buf,len,wfd)) < 0) {
			close(rfd);
			close(wfd);
			result = -1;
			break;
		    }
		    if (protocol_ver >= 1) {
			/* Tell run_erl size of terminal window */
			signal(SIGWINCH, handle_sigwinch);
			raise(SIGWINCH);
		    }
		    got_some = 1;
		}

		/*
		 * We successfully read at least one character. Write what we got.
		 */
		STATUS("Terminal write: \"");
		if (write_all(1, buf, len) != len) {
		    fprintf(stderr, "Error in writing to terminal.\n");
		    close(rfd);
		    close(wfd);
		    result = -1;
		    break;
		}
		STATUS("\" OK\r\n");
	    }
	}
    }

    /* 
     * Reset terminal characterstics 
     * XXX
     */
    tcsetattr(0, TCSANOW, &tty_rmode);
    return 0;
}

/* Call write() until entire buffer has been written or error.
 * Return len or -1.
 */
static int write_all(int fd, const char* buf, int len)
{
    int left = len;
    int written;
    while (left) {
	written = write(fd,buf,left);
	if (written < 0) {
	    return -1;
	}
	left -= written;
	buf += written;
    }
    return len;
}

static int window_size_seq(char* buf, size_t bufsz)
{
#ifdef TIOCGWINSZ
    struct winsize ws;
    static const char prefix[] = "\033_";
    static const char suffix[] = "\033\\";
    /* This Esc sequence is called "Application Program Command"
       and seems suitable to use for our own customized stuff. */

    if (ioctl(STDIN_FILENO, TIOCGWINSZ, &ws) == 0) {
	int len = sn_printf(buf, bufsz, "%swinsize=%u,%u%s",
			    prefix, ws.ws_col, ws.ws_row, suffix);
	return len;
    }
#endif /* TIOCGWINSZ */
    return 0;
}

/*   to_erl                     run_erl
 *     |                           |
 *     |---------- '\022' -------->| (session start)
 *     |                           |
 *     |<---- "[run_erl v1-0]" ----| (version interval)
 *     |                           |
 *     |--- Esc_"version=1"Esc\ -->| (common version)
 *     |                           |
 */
static int version_handshake(char* buf, int len, int wfd)
{
    unsigned re_high=0, re_low;
    char *end = find_str(buf,len,"]\n");
    
    if (end && sscanf(buf,"[run_erl v%u-%u",&re_high,&re_low)==2) {
	char wbuf[30];
	int wlen;

	if (re_low > RUN_ERL_HI_VER || re_high < RUN_ERL_LO_VER) {
	    fprintf(stderr,"Incompatible versions: to_erl=v%u-%u run_erl=v%u-%u\n",
		    RUN_ERL_HI_VER, RUN_ERL_LO_VER, re_high, re_low);
	    return -1;
	}
	/* Choose highest common version */
	protocol_ver = re_high < RUN_ERL_HI_VER ? re_high : RUN_ERL_HI_VER;

	wlen = sn_printf(wbuf, sizeof(wbuf), "\033_version=%u\033\\",
			 protocol_ver);
	if (write_all(wfd, wbuf, wlen) < 0) {
	    fprintf(stderr,"Failed to send version handshake\n");
	    return -1;
	}
	end += 2;
	len -= (end-buf);
	memmove(buf,end,len);

    }
    else {  /* we assume old run_erl without version handshake */
	protocol_ver = 0;
    }

    if (re_high != RUN_ERL_HI_VER) {
	fprintf(stderr,"run_erl has different version, "
		"using common protocol level %u\n", protocol_ver);
    }

    return len;
}


#ifdef DEBUG
#define S(x)  ((x) > 0 ? 1 : 0)

static void show_terminal_settings(struct termios *t)
{
  fprintf(stderr,"c_iflag:\n");
  fprintf(stderr,"Signal interrupt on break:   BRKINT  %d\n", S(t->c_iflag & BRKINT));
  fprintf(stderr,"Map CR to NL on input:       ICRNL   %d\n", S(t->c_iflag & ICRNL));
  fprintf(stderr,"Ignore break condition:      IGNBRK  %d\n", S(t->c_iflag & IGNBRK));
  fprintf(stderr,"Ignore CR:                   IGNCR   %d\n", S(t->c_iflag & IGNCR));
  fprintf(stderr,"Ignore char with par. err's: IGNPAR  %d\n", S(t->c_iflag & IGNPAR));
  fprintf(stderr,"Map NL to CR on input:       INLCR   %d\n", S(t->c_iflag & INLCR));
  fprintf(stderr,"Enable input parity check:   INPCK   %d\n", S(t->c_iflag & INPCK));
  fprintf(stderr,"Strip character              ISTRIP  %d\n", S(t->c_iflag & ISTRIP));
  fprintf(stderr,"Enable start/stop input ctrl IXOFF   %d\n", S(t->c_iflag & IXOFF));
  fprintf(stderr,"ditto output ctrl            IXON    %d\n", S(t->c_iflag & IXON));
  fprintf(stderr,"Mark parity errors           PARMRK  %d\n", S(t->c_iflag & PARMRK));
  fprintf(stderr,"\n");
  fprintf(stderr,"c_oflag:\n");
  fprintf(stderr,"Perform output processing    OPOST   %d\n", S(t->c_oflag & OPOST));
  fprintf(stderr,"\n");
  fprintf(stderr,"c_cflag:\n");
  fprintf(stderr,"Ignore modem status lines    CLOCAL  %d\n", S(t->c_cflag & CLOCAL));
  fprintf(stderr,"\n");
  fprintf(stderr,"c_local:\n");
  fprintf(stderr,"Enable echo                  ECHO    %d\n", S(t->c_lflag & ECHO));
  fprintf(stderr,"\n");
  fprintf(stderr,"c_cc:\n");
  fprintf(stderr,"c_cc[VEOF]                           %d\n", t->c_cc[VEOF]);
}
#endif