xref: /freebsd/bin/ed/main.c (revision f0adf7f5cdd241db2f2c817683191a6ef64a4e95)
1 /* main.c: This file contains the main control and user-interface routines
2    for the ed line editor. */
3 /*-
4  * Copyright (c) 1993 Andrew Moore, Talke Studio.
5  * All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  *
16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26  * SUCH DAMAGE.
27  */
28 
29 #ifndef lint
30 #if 0
31 static const char copyright[] =
32 "@(#) Copyright (c) 1993 Andrew Moore, Talke Studio. \n\
33  All rights reserved.\n";
34 #endif
35 #endif /* not lint */
36 
37 #include <sys/cdefs.h>
38 __FBSDID("$FreeBSD$");
39 
40 /*
41  * CREDITS
42  *
43  *	This program is based on the editor algorithm described in
44  *	Brian W. Kernighan and P. J. Plauger's book "Software Tools
45  *	in Pascal," Addison-Wesley, 1981.
46  *
47  *	The buffering algorithm is attributed to Rodney Ruddock of
48  *	the University of Guelph, Guelph, Ontario.
49  *
50  *	The cbc.c encryption code is adapted from
51  *	the bdes program by Matt Bishop of Dartmouth College,
52  *	Hanover, NH.
53  *
54  */
55 
56 #include <sys/types.h>
57 
58 #include <sys/ioctl.h>
59 #include <sys/wait.h>
60 #include <ctype.h>
61 #include <locale.h>
62 #include <pwd.h>
63 #include <setjmp.h>
64 
65 #include "ed.h"
66 
67 
68 #ifdef _POSIX_SOURCE
69 sigjmp_buf env;
70 #else
71 jmp_buf env;
72 #endif
73 
74 /* static buffers */
75 char stdinbuf[1];		/* stdin buffer */
76 char *shcmd;			/* shell command buffer */
77 int shcmdsz;			/* shell command buffer size */
78 int shcmdi;			/* shell command buffer index */
79 char *ibuf;			/* ed command-line buffer */
80 int ibufsz;			/* ed command-line buffer size */
81 char *ibufp;			/* pointer to ed command-line buffer */
82 
83 /* global flags */
84 int des = 0;			/* if set, use crypt(3) for i/o */
85 int garrulous = 0;		/* if set, print all error messages */
86 int isbinary;			/* if set, buffer contains ASCII NULs */
87 int isglobal;			/* if set, doing a global command */
88 int modified;			/* if set, buffer modified since last write */
89 int mutex = 0;			/* if set, signals set "sigflags" */
90 int red = 0;			/* if set, restrict shell/directory access */
91 int scripted = 0;		/* if set, suppress diagnostics */
92 int sigflags = 0;		/* if set, signals received while mutex set */
93 int sigactive = 0;		/* if set, signal handlers are enabled */
94 
95 char old_filename[PATH_MAX] = "";	/* default filename */
96 long current_addr;		/* current address in editor buffer */
97 long addr_last;			/* last address in editor buffer */
98 int lineno;			/* script line number */
99 const char *prompt;		/* command-line prompt */
100 const char *dps = "*";		/* default command-line prompt */
101 
102 const char usage[] = "usage: %s [-] [-sx] [-p string] [name]\n";
103 
104 /* ed: line editor */
105 int
106 main(int argc, char *argv[])
107 {
108 	int c, n;
109 	long status = 0;
110 #if __GNUC__
111 	/* Avoid longjmp clobbering */
112 	(void) &argc;
113 	(void) &argv;
114 #endif
115 
116 	(void)setlocale(LC_ALL, "");
117 
118 	red = (n = strlen(argv[0])) > 2 && argv[0][n - 3] == 'r';
119 top:
120 	while ((c = getopt(argc, argv, "p:sx")) != -1)
121 		switch(c) {
122 		case 'p':				/* set prompt */
123 			prompt = optarg;
124 			break;
125 		case 's':				/* run script */
126 			scripted = 1;
127 			break;
128 		case 'x':				/* use crypt */
129 #ifdef DES
130 			des = get_keyword();
131 #else
132 			fprintf(stderr, "crypt unavailable\n?\n");
133 #endif
134 			break;
135 
136 		default:
137 			fprintf(stderr, usage, argv[0]);
138 			exit(1);
139 		}
140 	argv += optind;
141 	argc -= optind;
142 	if (argc && **argv == '-') {
143 		scripted = 1;
144 		if (argc > 1) {
145 			optind = 1;
146 			goto top;
147 		}
148 		argv++;
149 		argc--;
150 	}
151 	/* assert: reliable signals! */
152 #ifdef SIGWINCH
153 	handle_winch(SIGWINCH);
154 	if (isatty(0)) signal(SIGWINCH, handle_winch);
155 #endif
156 	signal(SIGHUP, signal_hup);
157 	signal(SIGQUIT, SIG_IGN);
158 	signal(SIGINT, signal_int);
159 #ifdef _POSIX_SOURCE
160 	if ((status = sigsetjmp(env, 1)))
161 #else
162 	if ((status = setjmp(env)))
163 #endif
164 	{
165 		fputs("\n?\n", stderr);
166 		errmsg = "interrupt";
167 	} else {
168 		init_buffers();
169 		sigactive = 1;			/* enable signal handlers */
170 		if (argc && **argv && is_legal_filename(*argv)) {
171 			if (read_file(*argv, 0) < 0 && !isatty(0))
172 				quit(2);
173 			else if (**argv != '!')
174 				if (strlcpy(old_filename, *argv, sizeof(old_filename))
175 				    >= sizeof(old_filename))
176 					quit(2);
177 		} else if (argc) {
178 			fputs("?\n", stderr);
179 			if (**argv == '\0')
180 				errmsg = "invalid filename";
181 			if (!isatty(0))
182 				quit(2);
183 		}
184 	}
185 	for (;;) {
186 		if (status < 0 && garrulous)
187 			fprintf(stderr, "%s\n", errmsg);
188 		if (prompt) {
189 			printf("%s", prompt);
190 			fflush(stdout);
191 		}
192 		if ((n = get_tty_line()) < 0) {
193 			status = ERR;
194 			continue;
195 		} else if (n == 0) {
196 			if (modified && !scripted) {
197 				fputs("?\n", stderr);
198 				errmsg = "warning: file modified";
199 				if (!isatty(0)) {
200 					fprintf(stderr, garrulous ?
201 					    "script, line %d: %s\n" :
202 					    "", lineno, errmsg);
203 					quit(2);
204 				}
205 				clearerr(stdin);
206 				modified = 0;
207 				status = EMOD;
208 				continue;
209 			} else
210 				quit(0);
211 		} else if (ibuf[n - 1] != '\n') {
212 			/* discard line */
213 			errmsg = "unexpected end-of-file";
214 			clearerr(stdin);
215 			status = ERR;
216 			continue;
217 		}
218 		isglobal = 0;
219 		if ((status = extract_addr_range()) >= 0 &&
220 		    (status = exec_command()) >= 0)
221 			if (!status ||
222 			    (status = display_lines(current_addr, current_addr,
223 			        status)) >= 0)
224 				continue;
225 		switch (status) {
226 		case EOF:
227 			quit(0);
228 		case EMOD:
229 			modified = 0;
230 			fputs("?\n", stderr);		/* give warning */
231 			errmsg = "warning: file modified";
232 			if (!isatty(0)) {
233 				fprintf(stderr, garrulous ?
234 				    "script, line %d: %s\n" :
235 				    "", lineno, errmsg);
236 				quit(2);
237 			}
238 			break;
239 		case FATAL:
240 			if (!isatty(0))
241 				fprintf(stderr, garrulous ?
242 				    "script, line %d: %s\n" : "",
243 				    lineno, errmsg);
244 			else
245 				fprintf(stderr, garrulous ? "%s\n" : "",
246 				    errmsg);
247 			quit(3);
248 		default:
249 			fputs("?\n", stderr);
250 			if (!isatty(0)) {
251 				fprintf(stderr, garrulous ?
252 				    "script, line %d: %s\n" : "",
253 				    lineno, errmsg);
254 				quit(2);
255 			}
256 			break;
257 		}
258 	}
259 	/*NOTREACHED*/
260 }
261 
262 long first_addr, second_addr, addr_cnt;
263 
264 /* extract_addr_range: get line addresses from the command buffer until an
265    illegal address is seen; return status */
266 int
267 extract_addr_range(void)
268 {
269 	long addr;
270 
271 	addr_cnt = 0;
272 	first_addr = second_addr = current_addr;
273 	while ((addr = next_addr()) >= 0) {
274 		addr_cnt++;
275 		first_addr = second_addr;
276 		second_addr = addr;
277 		if (*ibufp != ',' && *ibufp != ';')
278 			break;
279 		else if (*ibufp++ == ';')
280 			current_addr = addr;
281 	}
282 	if ((addr_cnt = min(addr_cnt, 2)) == 1 || second_addr != addr)
283 		first_addr = second_addr;
284 	return (addr == ERR) ? ERR : 0;
285 }
286 
287 
288 #define SKIP_BLANKS() while (isspace((unsigned char)*ibufp) && *ibufp != '\n') ibufp++
289 
290 #define MUST_BE_FIRST() do {					\
291 	if (!first) {						\
292 		errmsg = "invalid address";			\
293 		return ERR;					\
294 	}							\
295 } while (0);
296 
297 /*  next_addr: return the next line address in the command buffer */
298 long
299 next_addr(void)
300 {
301 	const char *hd;
302 	long addr = current_addr;
303 	long n;
304 	int first = 1;
305 	int c;
306 
307 	SKIP_BLANKS();
308 	for (hd = ibufp;; first = 0)
309 		switch (c = *ibufp) {
310 		case '+':
311 		case '\t':
312 		case ' ':
313 		case '-':
314 		case '^':
315 			ibufp++;
316 			SKIP_BLANKS();
317 			if (isdigit((unsigned char)*ibufp)) {
318 				STRTOL(n, ibufp);
319 				addr += (c == '-' || c == '^') ? -n : n;
320 			} else if (!isspace((unsigned char)c))
321 				addr += (c == '-' || c == '^') ? -1 : 1;
322 			break;
323 		case '0': case '1': case '2':
324 		case '3': case '4': case '5':
325 		case '6': case '7': case '8': case '9':
326 			MUST_BE_FIRST();
327 			STRTOL(addr, ibufp);
328 			break;
329 		case '.':
330 		case '$':
331 			MUST_BE_FIRST();
332 			ibufp++;
333 			addr = (c == '.') ? current_addr : addr_last;
334 			break;
335 		case '/':
336 		case '?':
337 			MUST_BE_FIRST();
338 			if ((addr = get_matching_node_addr(
339 			    get_compiled_pattern(), c == '/')) < 0)
340 				return ERR;
341 			else if (c == *ibufp)
342 				ibufp++;
343 			break;
344 		case '\'':
345 			MUST_BE_FIRST();
346 			ibufp++;
347 			if ((addr = get_marked_node_addr(*ibufp++)) < 0)
348 				return ERR;
349 			break;
350 		case '%':
351 		case ',':
352 		case ';':
353 			if (first) {
354 				ibufp++;
355 				addr_cnt++;
356 				second_addr = (c == ';') ? current_addr : 1;
357 				addr = addr_last;
358 				break;
359 			}
360 			/* FALLTHROUGH */
361 		default:
362 			if (ibufp == hd)
363 				return EOF;
364 			else if (addr < 0 || addr_last < addr) {
365 				errmsg = "invalid address";
366 				return ERR;
367 			} else
368 				return addr;
369 		}
370 	/* NOTREACHED */
371 }
372 
373 
374 #ifdef BACKWARDS
375 /* GET_THIRD_ADDR: get a legal address from the command buffer */
376 #define GET_THIRD_ADDR(addr) \
377 { \
378 	long ol1, ol2; \
379 \
380 	ol1 = first_addr, ol2 = second_addr; \
381 	if (extract_addr_range() < 0) \
382 		return ERR; \
383 	else if (addr_cnt == 0) { \
384 		errmsg = "destination expected"; \
385 		return ERR; \
386 	} else if (second_addr < 0 || addr_last < second_addr) { \
387 		errmsg = "invalid address"; \
388 		return ERR; \
389 	} \
390 	addr = second_addr; \
391 	first_addr = ol1, second_addr = ol2; \
392 }
393 #else	/* BACKWARDS */
394 /* GET_THIRD_ADDR: get a legal address from the command buffer */
395 #define GET_THIRD_ADDR(addr) \
396 { \
397 	long ol1, ol2; \
398 \
399 	ol1 = first_addr, ol2 = second_addr; \
400 	if (extract_addr_range() < 0) \
401 		return ERR; \
402 	if (second_addr < 0 || addr_last < second_addr) { \
403 		errmsg = "invalid address"; \
404 		return ERR; \
405 	} \
406 	addr = second_addr; \
407 	first_addr = ol1, second_addr = ol2; \
408 }
409 #endif
410 
411 
412 /* GET_COMMAND_SUFFIX: verify the command suffix in the command buffer */
413 #define GET_COMMAND_SUFFIX() { \
414 	int done = 0; \
415 	do { \
416 		switch(*ibufp) { \
417 		case 'p': \
418 			gflag |= GPR, ibufp++; \
419 			break; \
420 		case 'l': \
421 			gflag |= GLS, ibufp++; \
422 			break; \
423 		case 'n': \
424 			gflag |= GNP, ibufp++; \
425 			break; \
426 		default: \
427 			done++; \
428 		} \
429 	} while (!done); \
430 	if (*ibufp++ != '\n') { \
431 		errmsg = "invalid command suffix"; \
432 		return ERR; \
433 	} \
434 }
435 
436 
437 /* sflags */
438 #define SGG 001		/* complement previous global substitute suffix */
439 #define SGP 002		/* complement previous print suffix */
440 #define SGR 004		/* use last regex instead of last pat */
441 #define SGF 010		/* repeat last substitution */
442 
443 int patlock = 0;	/* if set, pattern not freed by get_compiled_pattern() */
444 
445 long rows = 22;		/* scroll length: ws_row - 2 */
446 
447 /* exec_command: execute the next command in command buffer; return print
448    request, if any */
449 int
450 exec_command(void)
451 {
452 	static pattern_t *pat = NULL;
453 	static int sgflag = 0;
454 	static long sgnum = 0;
455 
456 	pattern_t *tpat;
457 	char *fnp;
458 	int gflag = 0;
459 	int sflags = 0;
460 	long addr = 0;
461 	int n = 0;
462 	int c;
463 
464 	SKIP_BLANKS();
465 	switch(c = *ibufp++) {
466 	case 'a':
467 		GET_COMMAND_SUFFIX();
468 		if (!isglobal) clear_undo_stack();
469 		if (append_lines(second_addr) < 0)
470 			return ERR;
471 		break;
472 	case 'c':
473 		if (check_addr_range(current_addr, current_addr) < 0)
474 			return ERR;
475 		GET_COMMAND_SUFFIX();
476 		if (!isglobal) clear_undo_stack();
477 		if (delete_lines(first_addr, second_addr) < 0 ||
478 		    append_lines(current_addr) < 0)
479 			return ERR;
480 		break;
481 	case 'd':
482 		if (check_addr_range(current_addr, current_addr) < 0)
483 			return ERR;
484 		GET_COMMAND_SUFFIX();
485 		if (!isglobal) clear_undo_stack();
486 		if (delete_lines(first_addr, second_addr) < 0)
487 			return ERR;
488 		else if ((addr = INC_MOD(current_addr, addr_last)) != 0)
489 			current_addr = addr;
490 		break;
491 	case 'e':
492 		if (modified && !scripted)
493 			return EMOD;
494 		/* FALLTHROUGH */
495 	case 'E':
496 		if (addr_cnt > 0) {
497 			errmsg = "unexpected address";
498 			return ERR;
499 		} else if (!isspace((unsigned char)*ibufp)) {
500 			errmsg = "unexpected command suffix";
501 			return ERR;
502 		} else if ((fnp = get_filename()) == NULL)
503 			return ERR;
504 		GET_COMMAND_SUFFIX();
505 		if (delete_lines(1, addr_last) < 0)
506 			return ERR;
507 		clear_undo_stack();
508 		if (close_sbuf() < 0)
509 			return ERR;
510 		else if (open_sbuf() < 0)
511 			return FATAL;
512 		if (*fnp && *fnp != '!') strcpy(old_filename, fnp);
513 #ifdef BACKWARDS
514 		if (*fnp == '\0' && *old_filename == '\0') {
515 			errmsg = "no current filename";
516 			return ERR;
517 		}
518 #endif
519 		if (read_file(*fnp ? fnp : old_filename, 0) < 0)
520 			return ERR;
521 		clear_undo_stack();
522 		modified = 0;
523 		u_current_addr = u_addr_last = -1;
524 		break;
525 	case 'f':
526 		if (addr_cnt > 0) {
527 			errmsg = "unexpected address";
528 			return ERR;
529 		} else if (!isspace((unsigned char)*ibufp)) {
530 			errmsg = "unexpected command suffix";
531 			return ERR;
532 		} else if ((fnp = get_filename()) == NULL)
533 			return ERR;
534 		else if (*fnp == '!') {
535 			errmsg = "invalid redirection";
536 			return ERR;
537 		}
538 		GET_COMMAND_SUFFIX();
539 		if (*fnp) strcpy(old_filename, fnp);
540 		printf("%s\n", strip_escapes(old_filename));
541 		break;
542 	case 'g':
543 	case 'v':
544 	case 'G':
545 	case 'V':
546 		if (isglobal) {
547 			errmsg = "cannot nest global commands";
548 			return ERR;
549 		} else if (check_addr_range(1, addr_last) < 0)
550 			return ERR;
551 		else if (build_active_list(c == 'g' || c == 'G') < 0)
552 			return ERR;
553 		else if ((n = (c == 'G' || c == 'V')))
554 			GET_COMMAND_SUFFIX();
555 		isglobal++;
556 		if (exec_global(n, gflag) < 0)
557 			return ERR;
558 		break;
559 	case 'h':
560 		if (addr_cnt > 0) {
561 			errmsg = "unexpected address";
562 			return ERR;
563 		}
564 		GET_COMMAND_SUFFIX();
565 		if (*errmsg) fprintf(stderr, "%s\n", errmsg);
566 		break;
567 	case 'H':
568 		if (addr_cnt > 0) {
569 			errmsg = "unexpected address";
570 			return ERR;
571 		}
572 		GET_COMMAND_SUFFIX();
573 		if ((garrulous = 1 - garrulous) && *errmsg)
574 			fprintf(stderr, "%s\n", errmsg);
575 		break;
576 	case 'i':
577 		if (second_addr == 0) {
578 			errmsg = "invalid address";
579 			return ERR;
580 		}
581 		GET_COMMAND_SUFFIX();
582 		if (!isglobal) clear_undo_stack();
583 		if (append_lines(second_addr - 1) < 0)
584 			return ERR;
585 		break;
586 	case 'j':
587 		if (check_addr_range(current_addr, current_addr + 1) < 0)
588 			return ERR;
589 		GET_COMMAND_SUFFIX();
590 		if (!isglobal) clear_undo_stack();
591 		if (first_addr != second_addr &&
592 		    join_lines(first_addr, second_addr) < 0)
593 			return ERR;
594 		break;
595 	case 'k':
596 		c = *ibufp++;
597 		if (second_addr == 0) {
598 			errmsg = "invalid address";
599 			return ERR;
600 		}
601 		GET_COMMAND_SUFFIX();
602 		if (mark_line_node(get_addressed_line_node(second_addr), c) < 0)
603 			return ERR;
604 		break;
605 	case 'l':
606 		if (check_addr_range(current_addr, current_addr) < 0)
607 			return ERR;
608 		GET_COMMAND_SUFFIX();
609 		if (display_lines(first_addr, second_addr, gflag | GLS) < 0)
610 			return ERR;
611 		gflag = 0;
612 		break;
613 	case 'm':
614 		if (check_addr_range(current_addr, current_addr) < 0)
615 			return ERR;
616 		GET_THIRD_ADDR(addr);
617 		if (first_addr <= addr && addr < second_addr) {
618 			errmsg = "invalid destination";
619 			return ERR;
620 		}
621 		GET_COMMAND_SUFFIX();
622 		if (!isglobal) clear_undo_stack();
623 		if (move_lines(addr) < 0)
624 			return ERR;
625 		break;
626 	case 'n':
627 		if (check_addr_range(current_addr, current_addr) < 0)
628 			return ERR;
629 		GET_COMMAND_SUFFIX();
630 		if (display_lines(first_addr, second_addr, gflag | GNP) < 0)
631 			return ERR;
632 		gflag = 0;
633 		break;
634 	case 'p':
635 		if (check_addr_range(current_addr, current_addr) < 0)
636 			return ERR;
637 		GET_COMMAND_SUFFIX();
638 		if (display_lines(first_addr, second_addr, gflag | GPR) < 0)
639 			return ERR;
640 		gflag = 0;
641 		break;
642 	case 'P':
643 		if (addr_cnt > 0) {
644 			errmsg = "unexpected address";
645 			return ERR;
646 		}
647 		GET_COMMAND_SUFFIX();
648 		prompt = prompt ? NULL : optarg ? optarg : dps;
649 		break;
650 	case 'q':
651 	case 'Q':
652 		if (addr_cnt > 0) {
653 			errmsg = "unexpected address";
654 			return ERR;
655 		}
656 		GET_COMMAND_SUFFIX();
657 		gflag =  (modified && !scripted && c == 'q') ? EMOD : EOF;
658 		break;
659 	case 'r':
660 		if (!isspace((unsigned char)*ibufp)) {
661 			errmsg = "unexpected command suffix";
662 			return ERR;
663 		} else if (addr_cnt == 0)
664 			second_addr = addr_last;
665 		if ((fnp = get_filename()) == NULL)
666 			return ERR;
667 		GET_COMMAND_SUFFIX();
668 		if (!isglobal) clear_undo_stack();
669 		if (*old_filename == '\0' && *fnp != '!')
670 			strcpy(old_filename, fnp);
671 #ifdef BACKWARDS
672 		if (*fnp == '\0' && *old_filename == '\0') {
673 			errmsg = "no current filename";
674 			return ERR;
675 		}
676 #endif
677 		if ((addr = read_file(*fnp ? fnp : old_filename, second_addr)) < 0)
678 			return ERR;
679 		else if (addr && addr != addr_last)
680 			modified = 1;
681 		break;
682 	case 's':
683 		do {
684 			switch(*ibufp) {
685 			case '\n':
686 				sflags |=SGF;
687 				break;
688 			case 'g':
689 				sflags |= SGG;
690 				ibufp++;
691 				break;
692 			case 'p':
693 				sflags |= SGP;
694 				ibufp++;
695 				break;
696 			case 'r':
697 				sflags |= SGR;
698 				ibufp++;
699 				break;
700 			case '0': case '1': case '2': case '3': case '4':
701 			case '5': case '6': case '7': case '8': case '9':
702 				STRTOL(sgnum, ibufp);
703 				sflags |= SGF;
704 				sgflag &= ~GSG;		/* override GSG */
705 				break;
706 			default:
707 				if (sflags) {
708 					errmsg = "invalid command suffix";
709 					return ERR;
710 				}
711 			}
712 		} while (sflags && *ibufp != '\n');
713 		if (sflags && !pat) {
714 			errmsg = "no previous substitution";
715 			return ERR;
716 		} else if (sflags & SGG)
717 			sgnum = 0;		/* override numeric arg */
718 		if (*ibufp != '\n' && *(ibufp + 1) == '\n') {
719 			errmsg = "invalid pattern delimiter";
720 			return ERR;
721 		}
722 		tpat = pat;
723 		SPL1();
724 		if ((!sflags || (sflags & SGR)) &&
725 		    (tpat = get_compiled_pattern()) == NULL) {
726 		 	SPL0();
727 			return ERR;
728 		} else if (tpat != pat) {
729 			if (pat) {
730 				regfree(pat);
731 				free(pat);
732 			}
733 			pat = tpat;
734 			patlock = 1;		/* reserve pattern */
735 		}
736 		SPL0();
737 		if (!sflags && extract_subst_tail(&sgflag, &sgnum) < 0)
738 			return ERR;
739 		else if (isglobal)
740 			sgflag |= GLB;
741 		else
742 			sgflag &= ~GLB;
743 		if (sflags & SGG)
744 			sgflag ^= GSG;
745 		if (sflags & SGP)
746 			sgflag ^= GPR, sgflag &= ~(GLS | GNP);
747 		do {
748 			switch(*ibufp) {
749 			case 'p':
750 				sgflag |= GPR, ibufp++;
751 				break;
752 			case 'l':
753 				sgflag |= GLS, ibufp++;
754 				break;
755 			case 'n':
756 				sgflag |= GNP, ibufp++;
757 				break;
758 			default:
759 				n++;
760 			}
761 		} while (!n);
762 		if (check_addr_range(current_addr, current_addr) < 0)
763 			return ERR;
764 		GET_COMMAND_SUFFIX();
765 		if (!isglobal) clear_undo_stack();
766 		if (search_and_replace(pat, sgflag, sgnum) < 0)
767 			return ERR;
768 		break;
769 	case 't':
770 		if (check_addr_range(current_addr, current_addr) < 0)
771 			return ERR;
772 		GET_THIRD_ADDR(addr);
773 		GET_COMMAND_SUFFIX();
774 		if (!isglobal) clear_undo_stack();
775 		if (copy_lines(addr) < 0)
776 			return ERR;
777 		break;
778 	case 'u':
779 		if (addr_cnt > 0) {
780 			errmsg = "unexpected address";
781 			return ERR;
782 		}
783 		GET_COMMAND_SUFFIX();
784 		if (pop_undo_stack() < 0)
785 			return ERR;
786 		break;
787 	case 'w':
788 	case 'W':
789 		if ((n = *ibufp) == 'q' || n == 'Q') {
790 			gflag = EOF;
791 			ibufp++;
792 		}
793 		if (!isspace((unsigned char)*ibufp)) {
794 			errmsg = "unexpected command suffix";
795 			return ERR;
796 		} else if ((fnp = get_filename()) == NULL)
797 			return ERR;
798 		if (addr_cnt == 0 && !addr_last)
799 			first_addr = second_addr = 0;
800 		else if (check_addr_range(1, addr_last) < 0)
801 			return ERR;
802 		GET_COMMAND_SUFFIX();
803 		if (*old_filename == '\0' && *fnp != '!')
804 			strcpy(old_filename, fnp);
805 #ifdef BACKWARDS
806 		if (*fnp == '\0' && *old_filename == '\0') {
807 			errmsg = "no current filename";
808 			return ERR;
809 		}
810 #endif
811 		if ((addr = write_file(*fnp ? fnp : old_filename,
812 		    (c == 'W') ? "a" : "w", first_addr, second_addr)) < 0)
813 			return ERR;
814 		else if (addr == addr_last)
815 			modified = 0;
816 		else if (modified && !scripted && n == 'q')
817 			gflag = EMOD;
818 		break;
819 	case 'x':
820 		if (addr_cnt > 0) {
821 			errmsg = "unexpected address";
822 			return ERR;
823 		}
824 		GET_COMMAND_SUFFIX();
825 #ifdef DES
826 		des = get_keyword();
827 #else
828 		errmsg = "crypt unavailable";
829 		return ERR;
830 #endif
831 		break;
832 	case 'z':
833 #ifdef BACKWARDS
834 		if (check_addr_range(first_addr = 1, current_addr + 1) < 0)
835 #else
836 		if (check_addr_range(first_addr = 1, current_addr + !isglobal) < 0)
837 #endif
838 			return ERR;
839 		else if ('0' < *ibufp && *ibufp <= '9')
840 			STRTOL(rows, ibufp);
841 		GET_COMMAND_SUFFIX();
842 		if (display_lines(second_addr, min(addr_last,
843 		    second_addr + rows), gflag) < 0)
844 			return ERR;
845 		gflag = 0;
846 		break;
847 	case '=':
848 		GET_COMMAND_SUFFIX();
849 		printf("%ld\n", addr_cnt ? second_addr : addr_last);
850 		break;
851 	case '!':
852 		if (addr_cnt > 0) {
853 			errmsg = "unexpected address";
854 			return ERR;
855 		} else if ((sflags = get_shell_command()) < 0)
856 			return ERR;
857 		GET_COMMAND_SUFFIX();
858 		if (sflags) printf("%s\n", shcmd + 1);
859 		system(shcmd + 1);
860 		if (!scripted) printf("!\n");
861 		break;
862 	case '\n':
863 #ifdef BACKWARDS
864 		if (check_addr_range(first_addr = 1, current_addr + 1) < 0
865 #else
866 		if (check_addr_range(first_addr = 1, current_addr + !isglobal) < 0
867 #endif
868 		 || display_lines(second_addr, second_addr, 0) < 0)
869 			return ERR;
870 		break;
871 	default:
872 		errmsg = "unknown command";
873 		return ERR;
874 	}
875 	return gflag;
876 }
877 
878 
879 /* check_addr_range: return status of address range check */
880 int
881 check_addr_range(long n, long m)
882 {
883 	if (addr_cnt == 0) {
884 		first_addr = n;
885 		second_addr = m;
886 	}
887 	if (first_addr > second_addr || 1 > first_addr ||
888 	    second_addr > addr_last) {
889 		errmsg = "invalid address";
890 		return ERR;
891 	}
892 	return 0;
893 }
894 
895 
896 /* get_matching_node_addr: return the address of the next line matching a
897    pattern in a given direction.  wrap around begin/end of editor buffer if
898    necessary */
899 long
900 get_matching_node_addr(pattern_t *pat, int dir)
901 {
902 	char *s;
903 	long n = current_addr;
904 	line_t *lp;
905 
906 	if (!pat) return ERR;
907 	do {
908 	       if ((n = dir ? INC_MOD(n, addr_last) : DEC_MOD(n, addr_last))) {
909 			lp = get_addressed_line_node(n);
910 			if ((s = get_sbuf_line(lp)) == NULL)
911 				return ERR;
912 			if (isbinary)
913 				NUL_TO_NEWLINE(s, lp->len);
914 			if (!regexec(pat, s, 0, NULL, 0))
915 				return n;
916 	       }
917 	} while (n != current_addr);
918 	errmsg = "no match";
919 	return  ERR;
920 }
921 
922 
923 /* get_filename: return pointer to copy of filename in the command buffer */
924 char *
925 get_filename(void)
926 {
927 	static char *file = NULL;
928 	static int filesz = 0;
929 
930 	int n;
931 
932 	if (*ibufp != '\n') {
933 		SKIP_BLANKS();
934 		if (*ibufp == '\n') {
935 			errmsg = "invalid filename";
936 			return NULL;
937 		} else if ((ibufp = get_extended_line(&n, 1)) == NULL)
938 			return NULL;
939 		else if (*ibufp == '!') {
940 			ibufp++;
941 			if ((n = get_shell_command()) < 0)
942 				return NULL;
943 			if (n)
944 				printf("%s\n", shcmd + 1);
945 			return shcmd;
946 		} else if (n > PATH_MAX - 1) {
947 			errmsg = "filename too long";
948 			return  NULL;
949 		}
950 	}
951 #ifndef BACKWARDS
952 	else if (*old_filename == '\0') {
953 		errmsg = "no current filename";
954 		return  NULL;
955 	}
956 #endif
957 	REALLOC(file, filesz, PATH_MAX, NULL);
958 	for (n = 0; *ibufp != '\n';)
959 		file[n++] = *ibufp++;
960 	file[n] = '\0';
961 	return is_legal_filename(file) ? file : NULL;
962 }
963 
964 
965 /* get_shell_command: read a shell command from stdin; return substitution
966    status */
967 int
968 get_shell_command(void)
969 {
970 	static char *buf = NULL;
971 	static int n = 0;
972 
973 	char *s;			/* substitution char pointer */
974 	int i = 0;
975 	int j = 0;
976 
977 	if (red) {
978 		errmsg = "shell access restricted";
979 		return ERR;
980 	} else if ((s = ibufp = get_extended_line(&j, 1)) == NULL)
981 		return ERR;
982 	REALLOC(buf, n, j + 1, ERR);
983 	buf[i++] = '!';			/* prefix command w/ bang */
984 	while (*ibufp != '\n')
985 		switch (*ibufp) {
986 		default:
987 			REALLOC(buf, n, i + 2, ERR);
988 			buf[i++] = *ibufp;
989 			if (*ibufp++ == '\\')
990 				buf[i++] = *ibufp++;
991 			break;
992 		case '!':
993 			if (s != ibufp) {
994 				REALLOC(buf, n, i + 1, ERR);
995 				buf[i++] = *ibufp++;
996 			}
997 #ifdef BACKWARDS
998 			else if (shcmd == NULL || *(shcmd + 1) == '\0')
999 #else
1000 			else if (shcmd == NULL)
1001 #endif
1002 			{
1003 				errmsg = "no previous command";
1004 				return ERR;
1005 			} else {
1006 				REALLOC(buf, n, i + shcmdi, ERR);
1007 				for (s = shcmd + 1; s < shcmd + shcmdi;)
1008 					buf[i++] = *s++;
1009 				s = ibufp++;
1010 			}
1011 			break;
1012 		case '%':
1013 			if (*old_filename  == '\0') {
1014 				errmsg = "no current filename";
1015 				return ERR;
1016 			}
1017 			j = strlen(s = strip_escapes(old_filename));
1018 			REALLOC(buf, n, i + j, ERR);
1019 			while (j--)
1020 				buf[i++] = *s++;
1021 			s = ibufp++;
1022 			break;
1023 		}
1024 	REALLOC(shcmd, shcmdsz, i + 1, ERR);
1025 	memcpy(shcmd, buf, i);
1026 	shcmd[shcmdi = i] = '\0';
1027 	return *s == '!' || *s == '%';
1028 }
1029 
1030 
1031 /* append_lines: insert text from stdin to after line n; stop when either a
1032    single period is read or EOF; return status */
1033 int
1034 append_lines(long n)
1035 {
1036 	int l;
1037 	const char *lp = ibuf;
1038 	const char *eot;
1039 	undo_t *up = NULL;
1040 
1041 	for (current_addr = n;;) {
1042 		if (!isglobal) {
1043 			if ((l = get_tty_line()) < 0)
1044 				return ERR;
1045 			else if (l == 0 || ibuf[l - 1] != '\n') {
1046 				clearerr(stdin);
1047 				return  l ? EOF : 0;
1048 			}
1049 			lp = ibuf;
1050 		} else if (*(lp = ibufp) == '\0')
1051 			return 0;
1052 		else {
1053 			while (*ibufp++ != '\n')
1054 				;
1055 			l = ibufp - lp;
1056 		}
1057 		if (l == 2 && lp[0] == '.' && lp[1] == '\n') {
1058 			return 0;
1059 		}
1060 		eot = lp + l;
1061 		SPL1();
1062 		do {
1063 			if ((lp = put_sbuf_line(lp)) == NULL) {
1064 				SPL0();
1065 				return ERR;
1066 			} else if (up)
1067 				up->t = get_addressed_line_node(current_addr);
1068 			else if ((up = push_undo_stack(UADD, current_addr,
1069 			    current_addr)) == NULL) {
1070 				SPL0();
1071 				return ERR;
1072 			}
1073 		} while (lp != eot);
1074 		modified = 1;
1075 		SPL0();
1076 	}
1077 	/* NOTREACHED */
1078 }
1079 
1080 
1081 /* join_lines: replace a range of lines with the joined text of those lines */
1082 int
1083 join_lines(long from, long to)
1084 {
1085 	static char *buf = NULL;
1086 	static int n;
1087 
1088 	char *s;
1089 	int size = 0;
1090 	line_t *bp, *ep;
1091 
1092 	ep = get_addressed_line_node(INC_MOD(to, addr_last));
1093 	bp = get_addressed_line_node(from);
1094 	for (; bp != ep; bp = bp->q_forw) {
1095 		if ((s = get_sbuf_line(bp)) == NULL)
1096 			return ERR;
1097 		REALLOC(buf, n, size + bp->len, ERR);
1098 		memcpy(buf + size, s, bp->len);
1099 		size += bp->len;
1100 	}
1101 	REALLOC(buf, n, size + 2, ERR);
1102 	memcpy(buf + size, "\n", 2);
1103 	if (delete_lines(from, to) < 0)
1104 		return ERR;
1105 	current_addr = from - 1;
1106 	SPL1();
1107 	if (put_sbuf_line(buf) == NULL ||
1108 	    push_undo_stack(UADD, current_addr, current_addr) == NULL) {
1109 		SPL0();
1110 		return ERR;
1111 	}
1112 	modified = 1;
1113 	SPL0();
1114 	return 0;
1115 }
1116 
1117 
1118 /* move_lines: move a range of lines */
1119 int
1120 move_lines(long addr)
1121 {
1122 	line_t *b1, *a1, *b2, *a2;
1123 	long n = INC_MOD(second_addr, addr_last);
1124 	long p = first_addr - 1;
1125 	int done = (addr == first_addr - 1 || addr == second_addr);
1126 
1127 	SPL1();
1128 	if (done) {
1129 		a2 = get_addressed_line_node(n);
1130 		b2 = get_addressed_line_node(p);
1131 		current_addr = second_addr;
1132 	} else if (push_undo_stack(UMOV, p, n) == NULL ||
1133 	    push_undo_stack(UMOV, addr, INC_MOD(addr, addr_last)) == NULL) {
1134 		SPL0();
1135 		return ERR;
1136 	} else {
1137 		a1 = get_addressed_line_node(n);
1138 		if (addr < first_addr) {
1139 			b1 = get_addressed_line_node(p);
1140 			b2 = get_addressed_line_node(addr);
1141 					/* this get_addressed_line_node last! */
1142 		} else {
1143 			b2 = get_addressed_line_node(addr);
1144 			b1 = get_addressed_line_node(p);
1145 					/* this get_addressed_line_node last! */
1146 		}
1147 		a2 = b2->q_forw;
1148 		REQUE(b2, b1->q_forw);
1149 		REQUE(a1->q_back, a2);
1150 		REQUE(b1, a1);
1151 		current_addr = addr + ((addr < first_addr) ?
1152 		    second_addr - first_addr + 1 : 0);
1153 	}
1154 	if (isglobal)
1155 		unset_active_nodes(b2->q_forw, a2);
1156 	modified = 1;
1157 	SPL0();
1158 	return 0;
1159 }
1160 
1161 
1162 /* copy_lines: copy a range of lines; return status */
1163 int
1164 copy_lines(long addr)
1165 {
1166 	line_t *lp, *np = get_addressed_line_node(first_addr);
1167 	undo_t *up = NULL;
1168 	long n = second_addr - first_addr + 1;
1169 	long m = 0;
1170 
1171 	current_addr = addr;
1172 	if (first_addr <= addr && addr < second_addr) {
1173 		n =  addr - first_addr + 1;
1174 		m = second_addr - addr;
1175 	}
1176 	for (; n > 0; n=m, m=0, np = get_addressed_line_node(current_addr + 1))
1177 		for (; n-- > 0; np = np->q_forw) {
1178 			SPL1();
1179 			if ((lp = dup_line_node(np)) == NULL) {
1180 				SPL0();
1181 				return ERR;
1182 			}
1183 			add_line_node(lp);
1184 			if (up)
1185 				up->t = lp;
1186 			else if ((up = push_undo_stack(UADD, current_addr,
1187 			    current_addr)) == NULL) {
1188 				SPL0();
1189 				return ERR;
1190 			}
1191 			modified = 1;
1192 			SPL0();
1193 		}
1194 	return 0;
1195 }
1196 
1197 
1198 /* delete_lines: delete a range of lines */
1199 int
1200 delete_lines(long from, long to)
1201 {
1202 	line_t *n, *p;
1203 
1204 	SPL1();
1205 	if (push_undo_stack(UDEL, from, to) == NULL) {
1206 		SPL0();
1207 		return ERR;
1208 	}
1209 	n = get_addressed_line_node(INC_MOD(to, addr_last));
1210 	p = get_addressed_line_node(from - 1);
1211 					/* this get_addressed_line_node last! */
1212 	if (isglobal)
1213 		unset_active_nodes(p->q_forw, n);
1214 	REQUE(p, n);
1215 	addr_last -= to - from + 1;
1216 	current_addr = from - 1;
1217 	modified = 1;
1218 	SPL0();
1219 	return 0;
1220 }
1221 
1222 
1223 /* display_lines: print a range of lines to stdout */
1224 int
1225 display_lines(long from, long to, int gflag)
1226 {
1227 	line_t *bp;
1228 	line_t *ep;
1229 	char *s;
1230 
1231 	if (!from) {
1232 		errmsg = "invalid address";
1233 		return ERR;
1234 	}
1235 	ep = get_addressed_line_node(INC_MOD(to, addr_last));
1236 	bp = get_addressed_line_node(from);
1237 	for (; bp != ep; bp = bp->q_forw) {
1238 		if ((s = get_sbuf_line(bp)) == NULL)
1239 			return ERR;
1240 		if (put_tty_line(s, bp->len, current_addr = from++, gflag) < 0)
1241 			return ERR;
1242 	}
1243 	return 0;
1244 }
1245 
1246 
1247 #define MAXMARK 26			/* max number of marks */
1248 
1249 line_t	*mark[MAXMARK];			/* line markers */
1250 int markno;				/* line marker count */
1251 
1252 /* mark_line_node: set a line node mark */
1253 int
1254 mark_line_node(line_t *lp, int n)
1255 {
1256 	if (!islower((unsigned char)n)) {
1257 		errmsg = "invalid mark character";
1258 		return ERR;
1259 	} else if (mark[n - 'a'] == NULL)
1260 		markno++;
1261 	mark[n - 'a'] = lp;
1262 	return 0;
1263 }
1264 
1265 
1266 /* get_marked_node_addr: return address of a marked line */
1267 long
1268 get_marked_node_addr(int n)
1269 {
1270 	if (!islower((unsigned char)n)) {
1271 		errmsg = "invalid mark character";
1272 		return ERR;
1273 	}
1274 	return get_line_node_addr(mark[n - 'a']);
1275 }
1276 
1277 
1278 /* unmark_line_node: clear line node mark */
1279 void
1280 unmark_line_node(line_t *lp)
1281 {
1282 	int i;
1283 
1284 	for (i = 0; markno && i < MAXMARK; i++)
1285 		if (mark[i] == lp) {
1286 			mark[i] = NULL;
1287 			markno--;
1288 		}
1289 }
1290 
1291 
1292 /* dup_line_node: return a pointer to a copy of a line node */
1293 line_t *
1294 dup_line_node(line_t *lp)
1295 {
1296 	line_t *np;
1297 
1298 	if ((np = (line_t *) malloc(sizeof(line_t))) == NULL) {
1299 		fprintf(stderr, "%s\n", strerror(errno));
1300 		errmsg = "out of memory";
1301 		return NULL;
1302 	}
1303 	np->seek = lp->seek;
1304 	np->len = lp->len;
1305 	return np;
1306 }
1307 
1308 
1309 /* has_trailing_escape:  return the parity of escapes preceding a character
1310    in a string */
1311 int
1312 has_trailing_escape(char *s, char *t)
1313 {
1314     return (s == t || *(t - 1) != '\\') ? 0 : !has_trailing_escape(s, t - 1);
1315 }
1316 
1317 
1318 /* strip_escapes: return copy of escaped string of at most length PATH_MAX */
1319 char *
1320 strip_escapes(char *s)
1321 {
1322 	static char *file = NULL;
1323 	static int filesz = 0;
1324 
1325 	int i = 0;
1326 
1327 	REALLOC(file, filesz, PATH_MAX, NULL);
1328 	while (i < filesz - 1	/* Worry about a possible trailing escape */
1329 	       && (file[i++] = (*s == '\\') ? *++s : *s))
1330 		s++;
1331 	return file;
1332 }
1333 
1334 
1335 void
1336 signal_hup(int signo)
1337 {
1338 	if (mutex)
1339 		sigflags |= (1 << (signo - 1));
1340 	else
1341 		handle_hup(signo);
1342 }
1343 
1344 
1345 void
1346 signal_int(int signo)
1347 {
1348 	if (mutex)
1349 		sigflags |= (1 << (signo - 1));
1350 	else
1351 		handle_int(signo);
1352 }
1353 
1354 
1355 void
1356 handle_hup(int signo)
1357 {
1358 	char *hup = NULL;		/* hup filename */
1359 	char *s;
1360 	char ed_hup[] = "ed.hup";
1361 	int n;
1362 
1363 	if (!sigactive)
1364 		quit(1);
1365 	sigflags &= ~(1 << (signo - 1));
1366 	if (addr_last && write_file(ed_hup, "w", 1, addr_last) < 0 &&
1367 	    (s = getenv("HOME")) != NULL &&
1368 	    (n = strlen(s)) + 8 <= PATH_MAX &&	/* "ed.hup" + '/' */
1369 	    (hup = (char *) malloc(n + 10)) != NULL) {
1370 		strcpy(hup, s);
1371 		if (hup[n - 1] != '/')
1372 			hup[n] = '/', hup[n+1] = '\0';
1373 		strcat(hup, "ed.hup");
1374 		write_file(hup, "w", 1, addr_last);
1375 	}
1376 	quit(2);
1377 }
1378 
1379 
1380 void
1381 handle_int(int signo)
1382 {
1383 	if (!sigactive)
1384 		quit(1);
1385 	sigflags &= ~(1 << (signo - 1));
1386 #ifdef _POSIX_SOURCE
1387 	siglongjmp(env, -1);
1388 #else
1389 	longjmp(env, -1);
1390 #endif
1391 }
1392 
1393 
1394 int cols = 72;				/* wrap column */
1395 
1396 void
1397 handle_winch(int signo)
1398 {
1399 	int save_errno = errno;
1400 
1401 	struct winsize ws;		/* window size structure */
1402 
1403 	sigflags &= ~(1 << (signo - 1));
1404 	if (ioctl(0, TIOCGWINSZ, (char *) &ws) >= 0) {
1405 		if (ws.ws_row > 2) rows = ws.ws_row - 2;
1406 		if (ws.ws_col > 8) cols = ws.ws_col - 8;
1407 	}
1408 	errno = save_errno;
1409 }
1410 
1411 
1412 /* is_legal_filename: return a legal filename */
1413 int
1414 is_legal_filename(char *s)
1415 {
1416 	if (red && (*s == '!' || !strcmp(s, "..") || strchr(s, '/'))) {
1417 		errmsg = "shell access restricted";
1418 		return 0;
1419 	}
1420 	return 1;
1421 }
1422