xref: /freebsd/bin/ed/main.c (revision cb166ce422ac2bc81f42c2a2e2cd68625c11478d)
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 static char * const copyright =
31 "@(#) Copyright (c) 1993 Andrew Moore, Talke Studio. \n\
32  All rights reserved.\n";
33 #endif /* not lint */
34 
35 #ifndef lint
36 #if 0
37 static char * const rcsid = "@(#)main.c,v 1.1 1994/02/01 00:34:42 alm Exp";
38 #else
39 static char * const rcsid =
40   "$FreeBSD$";
41 #endif
42 #endif /* not lint */
43 
44 /*
45  * CREDITS
46  *
47  *	This program is based on the editor algorithm described in
48  *	Brian W. Kernighan and P. J. Plauger's book "Software Tools
49  *	in Pascal," Addison-Wesley, 1981.
50  *
51  *	The buffering algorithm is attributed to Rodney Ruddock of
52  *	the University of Guelph, Guelph, Ontario.
53  *
54  *	The cbc.c encryption code is adapted from
55  *	the bdes program by Matt Bishop of Dartmouth College,
56  *	Hanover, NH.
57  *
58  */
59 
60 #include <sys/ioctl.h>
61 #include <sys/wait.h>
62 #include <ctype.h>
63 #include <locale.h>
64 #include <pwd.h>
65 #include <setjmp.h>
66 
67 #include "ed.h"
68 
69 
70 #ifdef _POSIX_SOURCE
71 sigjmp_buf env;
72 #else
73 jmp_buf env;
74 #endif
75 
76 /* static buffers */
77 char stdinbuf[1];		/* stdin buffer */
78 char *shcmd;			/* shell command buffer */
79 int shcmdsz;			/* shell command buffer size */
80 int shcmdi;			/* shell command buffer index */
81 char *ibuf;			/* ed command-line buffer */
82 int ibufsz;			/* ed command-line buffer size */
83 char *ibufp;			/* pointer to ed command-line buffer */
84 
85 /* global flags */
86 int des = 0;			/* if set, use crypt(3) for i/o */
87 int garrulous = 0;		/* if set, print all error messages */
88 int isbinary;			/* if set, buffer contains ASCII NULs */
89 int isglobal;			/* if set, doing a global command */
90 int modified;			/* if set, buffer modified since last write */
91 int mutex = 0;			/* if set, signals set "sigflags" */
92 int red = 0;			/* if set, restrict shell/directory access */
93 int scripted = 0;		/* if set, suppress diagnostics */
94 int sigflags = 0;		/* if set, signals received while mutex set */
95 int sigactive = 0;		/* if set, signal handlers are enabled */
96 
97 char old_filename[MAXPATHLEN + 1] = "";	/* default filename */
98 long current_addr;		/* current address in editor buffer */
99 long addr_last;			/* last address in editor buffer */
100 int lineno;			/* script line number */
101 char *prompt;			/* command-line prompt */
102 char *dps = "*";		/* default command-line prompt */
103 
104 char *usage = "usage: %s [-] [-sx] [-p string] [name]\n";
105 
106 /* ed: line editor */
107 int
108 main(argc, argv)
109 	int argc;
110 	char **argv;
111 {
112 	int c, n;
113 	long status = 0;
114 #if __GNUC__
115 	/* Avoid longjmp clobbering */
116 	(void) &argc;
117 	(void) &argv;
118 #endif
119 
120 	(void)setlocale(LC_ALL, "");
121 
122 	red = (n = strlen(argv[0])) > 2 && argv[0][n - 3] == 'r';
123 top:
124 	while ((c = getopt(argc, argv, "p:sx")) != -1)
125 		switch(c) {
126 		case 'p':				/* set prompt */
127 			prompt = optarg;
128 			break;
129 		case 's':				/* run script */
130 			scripted = 1;
131 			break;
132 		case 'x':				/* use crypt */
133 #ifdef DES
134 			des = get_keyword();
135 #else
136 			fprintf(stderr, "crypt unavailable\n?\n");
137 #endif
138 			break;
139 
140 		default:
141 			fprintf(stderr, usage, argv[0]);
142 			exit(1);
143 		}
144 	argv += optind;
145 	argc -= optind;
146 	if (argc && **argv == '-') {
147 		scripted = 1;
148 		if (argc > 1) {
149 			optind = 1;
150 			goto top;
151 		}
152 		argv++;
153 		argc--;
154 	}
155 	/* assert: reliable signals! */
156 #ifdef SIGWINCH
157 	handle_winch(SIGWINCH);
158 	if (isatty(0)) signal(SIGWINCH, handle_winch);
159 #endif
160 	signal(SIGHUP, signal_hup);
161 	signal(SIGQUIT, SIG_IGN);
162 	signal(SIGINT, signal_int);
163 #ifdef _POSIX_SOURCE
164 	if ((status = sigsetjmp(env, 1)))
165 #else
166 	if ((status = setjmp(env)))
167 #endif
168 	{
169 		fputs("\n?\n", stderr);
170 		sprintf(errmsg, "interrupt");
171 	} else {
172 		init_buffers();
173 		sigactive = 1;			/* enable signal handlers */
174 		if (argc && **argv && is_legal_filename(*argv)) {
175 			if (read_file(*argv, 0) < 0 && !isatty(0))
176 				quit(2);
177 			else if (**argv != '!')
178 				strcpy(old_filename, *argv);
179 		} else if (argc) {
180 			fputs("?\n", stderr);
181 			if (**argv == '\0')
182 				sprintf(errmsg, "invalid filename");
183 			if (!isatty(0))
184 				quit(2);
185 		}
186 	}
187 	for (;;) {
188 		if (status < 0 && garrulous)
189 			fprintf(stderr, "%s\n", errmsg);
190 		if (prompt) {
191 			printf("%s", prompt);
192 			fflush(stdout);
193 		}
194 		if ((n = get_tty_line()) < 0) {
195 			status = ERR;
196 			continue;
197 		} else if (n == 0) {
198 			if (modified && !scripted) {
199 				fputs("?\n", stderr);
200 				sprintf(errmsg, "warning: file modified");
201 				if (!isatty(0)) {
202 					fprintf(stderr, garrulous ?
203 					    "script, line %d: %s\n" :
204 					    "", lineno, errmsg);
205 					quit(2);
206 				}
207 				clearerr(stdin);
208 				modified = 0;
209 				status = EMOD;
210 				continue;
211 			} else
212 				quit(0);
213 		} else if (ibuf[n - 1] != '\n') {
214 			/* discard line */
215 			sprintf(errmsg, "unexpected end-of-file");
216 			clearerr(stdin);
217 			status = ERR;
218 			continue;
219 		}
220 		isglobal = 0;
221 		if ((status = extract_addr_range()) >= 0 &&
222 		    (status = exec_command()) >= 0)
223 			if (!status ||
224 			    (status = display_lines(current_addr, current_addr,
225 			        status)) >= 0)
226 				continue;
227 		switch (status) {
228 		case EOF:
229 			quit(0);
230 		case EMOD:
231 			modified = 0;
232 			fputs("?\n", stderr);		/* give warning */
233 			sprintf(errmsg, "warning: file modified");
234 			if (!isatty(0)) {
235 				fprintf(stderr, garrulous ?
236 				    "script, line %d: %s\n" :
237 				    "", lineno, errmsg);
238 				quit(2);
239 			}
240 			break;
241 		case FATAL:
242 			if (!isatty(0))
243 				fprintf(stderr, garrulous ?
244 				    "script, line %d: %s\n" : "",
245 				    lineno, errmsg);
246 			else
247 				fprintf(stderr, garrulous ? "%s\n" : "",
248 				    errmsg);
249 			quit(3);
250 		default:
251 			fputs("?\n", stderr);
252 			if (!isatty(0)) {
253 				fprintf(stderr, garrulous ?
254 				    "script, line %d: %s\n" : "",
255 				    lineno, errmsg);
256 				quit(2);
257 			}
258 			break;
259 		}
260 	}
261 	/*NOTREACHED*/
262 }
263 
264 long first_addr, second_addr, addr_cnt;
265 
266 /* extract_addr_range: get line addresses from the command buffer until an
267    illegal address is seen; return status */
268 int
269 extract_addr_range()
270 {
271 	long addr;
272 
273 	addr_cnt = 0;
274 	first_addr = second_addr = current_addr;
275 	while ((addr = next_addr()) >= 0) {
276 		addr_cnt++;
277 		first_addr = second_addr;
278 		second_addr = addr;
279 		if (*ibufp != ',' && *ibufp != ';')
280 			break;
281 		else if (*ibufp++ == ';')
282 			current_addr = addr;
283 	}
284 	if ((addr_cnt = min(addr_cnt, 2)) == 1 || second_addr != addr)
285 		first_addr = second_addr;
286 	return (addr == ERR) ? ERR : 0;
287 }
288 
289 
290 #define SKIP_BLANKS() while (isspace((unsigned char)*ibufp) && *ibufp != '\n') ibufp++
291 
292 #define MUST_BE_FIRST() \
293 	if (!first) { sprintf(errmsg, "invalid address"); return ERR; }
294 
295 /*  next_addr: return the next line address in the command buffer */
296 long
297 next_addr()
298 {
299 	char *hd;
300 	long addr = current_addr;
301 	long n;
302 	int first = 1;
303 	int c;
304 
305 	SKIP_BLANKS();
306 	for (hd = ibufp;; first = 0)
307 		switch (c = *ibufp) {
308 		case '+':
309 		case '\t':
310 		case ' ':
311 		case '-':
312 		case '^':
313 			ibufp++;
314 			SKIP_BLANKS();
315 			if (isdigit((unsigned char)*ibufp)) {
316 				STRTOL(n, ibufp);
317 				addr += (c == '-' || c == '^') ? -n : n;
318 			} else if (!isspace((unsigned char)c))
319 				addr += (c == '-' || c == '^') ? -1 : 1;
320 			break;
321 		case '0': case '1': case '2':
322 		case '3': case '4': case '5':
323 		case '6': case '7': case '8': case '9':
324 			MUST_BE_FIRST();
325 			STRTOL(addr, ibufp);
326 			break;
327 		case '.':
328 		case '$':
329 			MUST_BE_FIRST();
330 			ibufp++;
331 			addr = (c == '.') ? current_addr : addr_last;
332 			break;
333 		case '/':
334 		case '?':
335 			MUST_BE_FIRST();
336 			if ((addr = get_matching_node_addr(
337 			    get_compiled_pattern(), c == '/')) < 0)
338 				return ERR;
339 			else if (c == *ibufp)
340 				ibufp++;
341 			break;
342 		case '\'':
343 			MUST_BE_FIRST();
344 			ibufp++;
345 			if ((addr = get_marked_node_addr(*ibufp++)) < 0)
346 				return ERR;
347 			break;
348 		case '%':
349 		case ',':
350 		case ';':
351 			if (first) {
352 				ibufp++;
353 				addr_cnt++;
354 				second_addr = (c == ';') ? current_addr : 1;
355 				addr = addr_last;
356 				break;
357 			}
358 			/* FALL THROUGH */
359 		default:
360 			if (ibufp == hd)
361 				return EOF;
362 			else if (addr < 0 || addr_last < addr) {
363 				sprintf(errmsg, "invalid address");
364 				return ERR;
365 			} else
366 				return addr;
367 		}
368 	/* NOTREACHED */
369 }
370 
371 
372 #ifdef BACKWARDS
373 /* GET_THIRD_ADDR: get a legal address from the command buffer */
374 #define GET_THIRD_ADDR(addr) \
375 { \
376 	long ol1, ol2; \
377 \
378 	ol1 = first_addr, ol2 = second_addr; \
379 	if (extract_addr_range() < 0) \
380 		return ERR; \
381 	else if (addr_cnt == 0) { \
382 		sprintf(errmsg, "destination expected"); \
383 		return ERR; \
384 	} else if (second_addr < 0 || addr_last < second_addr) { \
385 		sprintf(errmsg, "invalid address"); \
386 		return ERR; \
387 	} \
388 	addr = second_addr; \
389 	first_addr = ol1, second_addr = ol2; \
390 }
391 #else	/* BACKWARDS */
392 /* GET_THIRD_ADDR: get a legal address from the command buffer */
393 #define GET_THIRD_ADDR(addr) \
394 { \
395 	long ol1, ol2; \
396 \
397 	ol1 = first_addr, ol2 = second_addr; \
398 	if (extract_addr_range() < 0) \
399 		return ERR; \
400 	if (second_addr < 0 || addr_last < second_addr) { \
401 		sprintf(errmsg, "invalid address"); \
402 		return ERR; \
403 	} \
404 	addr = second_addr; \
405 	first_addr = ol1, second_addr = ol2; \
406 }
407 #endif
408 
409 
410 /* GET_COMMAND_SUFFIX: verify the command suffix in the command buffer */
411 #define GET_COMMAND_SUFFIX() { \
412 	int done = 0; \
413 	do { \
414 		switch(*ibufp) { \
415 		case 'p': \
416 			gflag |= GPR, ibufp++; \
417 			break; \
418 		case 'l': \
419 			gflag |= GLS, ibufp++; \
420 			break; \
421 		case 'n': \
422 			gflag |= GNP, ibufp++; \
423 			break; \
424 		default: \
425 			done++; \
426 		} \
427 	} while (!done); \
428 	if (*ibufp++ != '\n') { \
429 		sprintf(errmsg, "invalid command suffix"); \
430 		return ERR; \
431 	} \
432 }
433 
434 
435 /* sflags */
436 #define SGG 001		/* complement previous global substitute suffix */
437 #define SGP 002		/* complement previous print suffix */
438 #define SGR 004		/* use last regex instead of last pat */
439 #define SGF 010		/* repeat last substitution */
440 
441 int patlock = 0;	/* if set, pattern not freed by get_compiled_pattern() */
442 
443 long rows = 22;		/* scroll length: ws_row - 2 */
444 
445 /* exec_command: execute the next command in command buffer; return print
446    request, if any */
447 int
448 exec_command()
449 {
450 	extern long u_current_addr;
451 	extern long u_addr_last;
452 
453 	static pattern_t *pat = NULL;
454 	static int sgflag = 0;
455 	static long sgnum = 0;
456 
457 	pattern_t *tpat;
458 	char *fnp;
459 	int gflag = 0;
460 	int sflags = 0;
461 	long addr = 0;
462 	int n = 0;
463 	int c;
464 
465 	SKIP_BLANKS();
466 	switch(c = *ibufp++) {
467 	case 'a':
468 		GET_COMMAND_SUFFIX();
469 		if (!isglobal) clear_undo_stack();
470 		if (append_lines(second_addr) < 0)
471 			return ERR;
472 		break;
473 	case 'c':
474 		if (check_addr_range(current_addr, current_addr) < 0)
475 			return ERR;
476 		GET_COMMAND_SUFFIX();
477 		if (!isglobal) clear_undo_stack();
478 		if (delete_lines(first_addr, second_addr) < 0 ||
479 		    append_lines(current_addr) < 0)
480 			return ERR;
481 		break;
482 	case 'd':
483 		if (check_addr_range(current_addr, current_addr) < 0)
484 			return ERR;
485 		GET_COMMAND_SUFFIX();
486 		if (!isglobal) clear_undo_stack();
487 		if (delete_lines(first_addr, second_addr) < 0)
488 			return ERR;
489 		else if ((addr = INC_MOD(current_addr, addr_last)) != 0)
490 			current_addr = addr;
491 		break;
492 	case 'e':
493 		if (modified && !scripted)
494 			return EMOD;
495 		/* fall through */
496 	case 'E':
497 		if (addr_cnt > 0) {
498 			sprintf(errmsg, "unexpected address");
499 			return ERR;
500 		} else if (!isspace((unsigned char)*ibufp)) {
501 			sprintf(errmsg, "unexpected command suffix");
502 			return ERR;
503 		} else if ((fnp = get_filename()) == NULL)
504 			return ERR;
505 		GET_COMMAND_SUFFIX();
506 		if (delete_lines(1, addr_last) < 0)
507 			return ERR;
508 		clear_undo_stack();
509 		if (close_sbuf() < 0)
510 			return ERR;
511 		else if (open_sbuf() < 0)
512 			return FATAL;
513 		if (*fnp && *fnp != '!') strcpy(old_filename, fnp);
514 #ifdef BACKWARDS
515 		if (*fnp == '\0' && *old_filename == '\0') {
516 			sprintf(errmsg, "no current filename");
517 			return ERR;
518 		}
519 #endif
520 		if (read_file(*fnp ? fnp : old_filename, 0) < 0)
521 			return ERR;
522 		clear_undo_stack();
523 		modified = 0;
524 		u_current_addr = u_addr_last = -1;
525 		break;
526 	case 'f':
527 		if (addr_cnt > 0) {
528 			sprintf(errmsg, "unexpected address");
529 			return ERR;
530 		} else if (!isspace((unsigned char)*ibufp)) {
531 			sprintf(errmsg, "unexpected command suffix");
532 			return ERR;
533 		} else if ((fnp = get_filename()) == NULL)
534 			return ERR;
535 		else if (*fnp == '!') {
536 			sprintf(errmsg, "invalid redirection");
537 			return ERR;
538 		}
539 		GET_COMMAND_SUFFIX();
540 		if (*fnp) strcpy(old_filename, fnp);
541 		printf("%s\n", strip_escapes(old_filename));
542 		break;
543 	case 'g':
544 	case 'v':
545 	case 'G':
546 	case 'V':
547 		if (isglobal) {
548 			sprintf(errmsg, "cannot nest global commands");
549 			return ERR;
550 		} else if (check_addr_range(1, addr_last) < 0)
551 			return ERR;
552 		else if (build_active_list(c == 'g' || c == 'G') < 0)
553 			return ERR;
554 		else if ((n = (c == 'G' || c == 'V')))
555 			GET_COMMAND_SUFFIX();
556 		isglobal++;
557 		if (exec_global(n, gflag) < 0)
558 			return ERR;
559 		break;
560 	case 'h':
561 		if (addr_cnt > 0) {
562 			sprintf(errmsg, "unexpected address");
563 			return ERR;
564 		}
565 		GET_COMMAND_SUFFIX();
566 		if (*errmsg) fprintf(stderr, "%s\n", errmsg);
567 		break;
568 	case 'H':
569 		if (addr_cnt > 0) {
570 			sprintf(errmsg, "unexpected address");
571 			return ERR;
572 		}
573 		GET_COMMAND_SUFFIX();
574 		if ((garrulous = 1 - garrulous) && *errmsg)
575 			fprintf(stderr, "%s\n", errmsg);
576 		break;
577 	case 'i':
578 		if (second_addr == 0) {
579 			sprintf(errmsg, "invalid address");
580 			return ERR;
581 		}
582 		GET_COMMAND_SUFFIX();
583 		if (!isglobal) clear_undo_stack();
584 		if (append_lines(second_addr - 1) < 0)
585 			return ERR;
586 		break;
587 	case 'j':
588 		if (check_addr_range(current_addr, current_addr + 1) < 0)
589 			return ERR;
590 		GET_COMMAND_SUFFIX();
591 		if (!isglobal) clear_undo_stack();
592 		if (first_addr != second_addr &&
593 		    join_lines(first_addr, second_addr) < 0)
594 			return ERR;
595 		break;
596 	case 'k':
597 		c = *ibufp++;
598 		if (second_addr == 0) {
599 			sprintf(errmsg, "invalid address");
600 			return ERR;
601 		}
602 		GET_COMMAND_SUFFIX();
603 		if (mark_line_node(get_addressed_line_node(second_addr), c) < 0)
604 			return ERR;
605 		break;
606 	case 'l':
607 		if (check_addr_range(current_addr, current_addr) < 0)
608 			return ERR;
609 		GET_COMMAND_SUFFIX();
610 		if (display_lines(first_addr, second_addr, gflag | GLS) < 0)
611 			return ERR;
612 		gflag = 0;
613 		break;
614 	case 'm':
615 		if (check_addr_range(current_addr, current_addr) < 0)
616 			return ERR;
617 		GET_THIRD_ADDR(addr);
618 		if (first_addr <= addr && addr < second_addr) {
619 			sprintf(errmsg, "invalid destination");
620 			return ERR;
621 		}
622 		GET_COMMAND_SUFFIX();
623 		if (!isglobal) clear_undo_stack();
624 		if (move_lines(addr) < 0)
625 			return ERR;
626 		break;
627 	case 'n':
628 		if (check_addr_range(current_addr, current_addr) < 0)
629 			return ERR;
630 		GET_COMMAND_SUFFIX();
631 		if (display_lines(first_addr, second_addr, gflag | GNP) < 0)
632 			return ERR;
633 		gflag = 0;
634 		break;
635 	case 'p':
636 		if (check_addr_range(current_addr, current_addr) < 0)
637 			return ERR;
638 		GET_COMMAND_SUFFIX();
639 		if (display_lines(first_addr, second_addr, gflag | GPR) < 0)
640 			return ERR;
641 		gflag = 0;
642 		break;
643 	case 'P':
644 		if (addr_cnt > 0) {
645 			sprintf(errmsg, "unexpected address");
646 			return ERR;
647 		}
648 		GET_COMMAND_SUFFIX();
649 		prompt = prompt ? NULL : optarg ? optarg : dps;
650 		break;
651 	case 'q':
652 	case 'Q':
653 		if (addr_cnt > 0) {
654 			sprintf(errmsg, "unexpected address");
655 			return ERR;
656 		}
657 		GET_COMMAND_SUFFIX();
658 		gflag =  (modified && !scripted && c == 'q') ? EMOD : EOF;
659 		break;
660 	case 'r':
661 		if (!isspace((unsigned char)*ibufp)) {
662 			sprintf(errmsg, "unexpected command suffix");
663 			return ERR;
664 		} else if (addr_cnt == 0)
665 			second_addr = addr_last;
666 		if ((fnp = get_filename()) == NULL)
667 			return ERR;
668 		GET_COMMAND_SUFFIX();
669 		if (!isglobal) clear_undo_stack();
670 		if (*old_filename == '\0' && *fnp != '!')
671 			strcpy(old_filename, fnp);
672 #ifdef BACKWARDS
673 		if (*fnp == '\0' && *old_filename == '\0') {
674 			sprintf(errmsg, "no current filename");
675 			return ERR;
676 		}
677 #endif
678 		if ((addr = read_file(*fnp ? fnp : old_filename, second_addr)) < 0)
679 			return ERR;
680 		else if (addr && addr != addr_last)
681 			modified = 1;
682 		break;
683 	case 's':
684 		do {
685 			switch(*ibufp) {
686 			case '\n':
687 				sflags |=SGF;
688 				break;
689 			case 'g':
690 				sflags |= SGG;
691 				ibufp++;
692 				break;
693 			case 'p':
694 				sflags |= SGP;
695 				ibufp++;
696 				break;
697 			case 'r':
698 				sflags |= SGR;
699 				ibufp++;
700 				break;
701 			case '0': case '1': case '2': case '3': case '4':
702 			case '5': case '6': case '7': case '8': case '9':
703 				STRTOL(sgnum, ibufp);
704 				sflags |= SGF;
705 				sgflag &= ~GSG;		/* override GSG */
706 				break;
707 			default:
708 				if (sflags) {
709 					sprintf(errmsg, "invalid command suffix");
710 					return ERR;
711 				}
712 			}
713 		} while (sflags && *ibufp != '\n');
714 		if (sflags && !pat) {
715 			sprintf(errmsg, "no previous substitution");
716 			return ERR;
717 		} else if (sflags & SGG)
718 			sgnum = 0;		/* override numeric arg */
719 		if (*ibufp != '\n' && *(ibufp + 1) == '\n') {
720 			sprintf(errmsg, "invalid pattern delimiter");
721 			return ERR;
722 		}
723 		tpat = pat;
724 		SPL1();
725 		if ((!sflags || (sflags & SGR)) &&
726 		    (tpat = get_compiled_pattern()) == NULL) {
727 		 	SPL0();
728 			return ERR;
729 		} else if (tpat != pat) {
730 			if (pat) {
731 				regfree(pat);
732 				free(pat);
733 			}
734 			pat = tpat;
735 			patlock = 1;		/* reserve pattern */
736 		}
737 		SPL0();
738 		if (!sflags && extract_subst_tail(&sgflag, &sgnum) < 0)
739 			return ERR;
740 		else if (isglobal)
741 			sgflag |= GLB;
742 		else
743 			sgflag &= ~GLB;
744 		if (sflags & SGG)
745 			sgflag ^= GSG;
746 		if (sflags & SGP)
747 			sgflag ^= GPR, sgflag &= ~(GLS | GNP);
748 		do {
749 			switch(*ibufp) {
750 			case 'p':
751 				sgflag |= GPR, ibufp++;
752 				break;
753 			case 'l':
754 				sgflag |= GLS, ibufp++;
755 				break;
756 			case 'n':
757 				sgflag |= GNP, ibufp++;
758 				break;
759 			default:
760 				n++;
761 			}
762 		} while (!n);
763 		if (check_addr_range(current_addr, current_addr) < 0)
764 			return ERR;
765 		GET_COMMAND_SUFFIX();
766 		if (!isglobal) clear_undo_stack();
767 		if (search_and_replace(pat, sgflag, sgnum) < 0)
768 			return ERR;
769 		break;
770 	case 't':
771 		if (check_addr_range(current_addr, current_addr) < 0)
772 			return ERR;
773 		GET_THIRD_ADDR(addr);
774 		GET_COMMAND_SUFFIX();
775 		if (!isglobal) clear_undo_stack();
776 		if (copy_lines(addr) < 0)
777 			return ERR;
778 		break;
779 	case 'u':
780 		if (addr_cnt > 0) {
781 			sprintf(errmsg, "unexpected address");
782 			return ERR;
783 		}
784 		GET_COMMAND_SUFFIX();
785 		if (pop_undo_stack() < 0)
786 			return ERR;
787 		break;
788 	case 'w':
789 	case 'W':
790 		if ((n = *ibufp) == 'q' || n == 'Q') {
791 			gflag = EOF;
792 			ibufp++;
793 		}
794 		if (!isspace((unsigned char)*ibufp)) {
795 			sprintf(errmsg, "unexpected command suffix");
796 			return ERR;
797 		} else if ((fnp = get_filename()) == NULL)
798 			return ERR;
799 		if (addr_cnt == 0 && !addr_last)
800 			first_addr = second_addr = 0;
801 		else if (check_addr_range(1, addr_last) < 0)
802 			return ERR;
803 		GET_COMMAND_SUFFIX();
804 		if (*old_filename == '\0' && *fnp != '!')
805 			strcpy(old_filename, fnp);
806 #ifdef BACKWARDS
807 		if (*fnp == '\0' && *old_filename == '\0') {
808 			sprintf(errmsg, "no current filename");
809 			return ERR;
810 		}
811 #endif
812 		if ((addr = write_file(*fnp ? fnp : old_filename,
813 		    (c == 'W') ? "a" : "w", first_addr, second_addr)) < 0)
814 			return ERR;
815 		else if (addr == addr_last)
816 			modified = 0;
817 		else if (modified && !scripted && n == 'q')
818 			gflag = EMOD;
819 		break;
820 	case 'x':
821 		if (addr_cnt > 0) {
822 			sprintf(errmsg, "unexpected address");
823 			return ERR;
824 		}
825 		GET_COMMAND_SUFFIX();
826 #ifdef DES
827 		des = get_keyword();
828 #else
829 		sprintf(errmsg, "crypt unavailable");
830 		return ERR;
831 #endif
832 		break;
833 	case 'z':
834 #ifdef BACKWARDS
835 		if (check_addr_range(first_addr = 1, current_addr + 1) < 0)
836 #else
837 		if (check_addr_range(first_addr = 1, current_addr + !isglobal) < 0)
838 #endif
839 			return ERR;
840 		else if ('0' < *ibufp && *ibufp <= '9')
841 			STRTOL(rows, ibufp);
842 		GET_COMMAND_SUFFIX();
843 		if (display_lines(second_addr, min(addr_last,
844 		    second_addr + rows), gflag) < 0)
845 			return ERR;
846 		gflag = 0;
847 		break;
848 	case '=':
849 		GET_COMMAND_SUFFIX();
850 		printf("%ld\n", addr_cnt ? second_addr : addr_last);
851 		break;
852 	case '!':
853 		if (addr_cnt > 0) {
854 			sprintf(errmsg, "unexpected address");
855 			return ERR;
856 		} else if ((sflags = get_shell_command()) < 0)
857 			return ERR;
858 		GET_COMMAND_SUFFIX();
859 		if (sflags) printf("%s\n", shcmd + 1);
860 		system(shcmd + 1);
861 		if (!scripted) printf("!\n");
862 		break;
863 	case '\n':
864 #ifdef BACKWARDS
865 		if (check_addr_range(first_addr = 1, current_addr + 1) < 0
866 #else
867 		if (check_addr_range(first_addr = 1, current_addr + !isglobal) < 0
868 #endif
869 		 || display_lines(second_addr, second_addr, 0) < 0)
870 			return ERR;
871 		break;
872 	default:
873 		sprintf(errmsg, "unknown command");
874 		return ERR;
875 	}
876 	return gflag;
877 }
878 
879 
880 /* check_addr_range: return status of address range check */
881 int
882 check_addr_range(n, m)
883 	long n, m;
884 {
885 	if (addr_cnt == 0) {
886 		first_addr = n;
887 		second_addr = m;
888 	}
889 	if (first_addr > second_addr || 1 > first_addr ||
890 	    second_addr > addr_last) {
891 		sprintf(errmsg, "invalid address");
892 		return ERR;
893 	}
894 	return 0;
895 }
896 
897 
898 /* get_matching_node_addr: return the address of the next line matching a
899    pattern in a given direction.  wrap around begin/end of editor buffer if
900    necessary */
901 long
902 get_matching_node_addr(pat, dir)
903 	pattern_t *pat;
904 	int dir;
905 {
906 	char *s;
907 	long n = current_addr;
908 	line_t *lp;
909 
910 	if (!pat) return ERR;
911 	do {
912 	       if ((n = dir ? INC_MOD(n, addr_last) : DEC_MOD(n, addr_last))) {
913 			lp = get_addressed_line_node(n);
914 			if ((s = get_sbuf_line(lp)) == NULL)
915 				return ERR;
916 			if (isbinary)
917 				NUL_TO_NEWLINE(s, lp->len);
918 			if (!regexec(pat, s, 0, NULL, 0))
919 				return n;
920 	       }
921 	} while (n != current_addr);
922 	sprintf(errmsg, "no match");
923 	return  ERR;
924 }
925 
926 
927 /* get_filename: return pointer to copy of filename in the command buffer */
928 char *
929 get_filename()
930 {
931 	static char *file = NULL;
932 	static int filesz = 0;
933 
934 	int n;
935 
936 	if (*ibufp != '\n') {
937 		SKIP_BLANKS();
938 		if (*ibufp == '\n') {
939 			sprintf(errmsg, "invalid filename");
940 			return NULL;
941 		} else if ((ibufp = get_extended_line(&n, 1)) == NULL)
942 			return NULL;
943 		else if (*ibufp == '!') {
944 			ibufp++;
945 			if ((n = get_shell_command()) < 0)
946 				return NULL;
947 			if (n) printf("%s\n", shcmd + 1);
948 			return shcmd;
949 		} else if (n - 1 > MAXPATHLEN) {
950 			sprintf(errmsg, "filename too long");
951 			return  NULL;
952 		}
953 	}
954 #ifndef BACKWARDS
955 	else if (*old_filename == '\0') {
956 		sprintf(errmsg, "no current filename");
957 		return  NULL;
958 	}
959 #endif
960 	REALLOC(file, filesz, MAXPATHLEN + 1, NULL);
961 	for (n = 0; *ibufp != '\n';)
962 		file[n++] = *ibufp++;
963 	file[n] = '\0';
964 	return is_legal_filename(file) ? file : NULL;
965 }
966 
967 
968 /* get_shell_command: read a shell command from stdin; return substitution
969    status */
970 int
971 get_shell_command()
972 {
973 	static char *buf = NULL;
974 	static int n = 0;
975 
976 	char *s;			/* substitution char pointer */
977 	int i = 0;
978 	int j = 0;
979 
980 	if (red) {
981 		sprintf(errmsg, "shell access restricted");
982 		return ERR;
983 	} else if ((s = ibufp = get_extended_line(&j, 1)) == NULL)
984 		return ERR;
985 	REALLOC(buf, n, j + 1, ERR);
986 	buf[i++] = '!';			/* prefix command w/ bang */
987 	while (*ibufp != '\n')
988 		switch (*ibufp) {
989 		default:
990 			REALLOC(buf, n, i + 2, ERR);
991 			buf[i++] = *ibufp;
992 			if (*ibufp++ == '\\')
993 				buf[i++] = *ibufp++;
994 			break;
995 		case '!':
996 			if (s != ibufp) {
997 				REALLOC(buf, n, i + 1, ERR);
998 				buf[i++] = *ibufp++;
999 			}
1000 #ifdef BACKWARDS
1001 			else if (shcmd == NULL || *(shcmd + 1) == '\0')
1002 #else
1003 			else if (shcmd == NULL)
1004 #endif
1005 			{
1006 				sprintf(errmsg, "no previous command");
1007 				return ERR;
1008 			} else {
1009 				REALLOC(buf, n, i + shcmdi, ERR);
1010 				for (s = shcmd + 1; s < shcmd + shcmdi;)
1011 					buf[i++] = *s++;
1012 				s = ibufp++;
1013 			}
1014 			break;
1015 		case '%':
1016 			if (*old_filename  == '\0') {
1017 				sprintf(errmsg, "no current filename");
1018 				return ERR;
1019 			}
1020 			j = strlen(s = strip_escapes(old_filename));
1021 			REALLOC(buf, n, i + j, ERR);
1022 			while (j--)
1023 				buf[i++] = *s++;
1024 			s = ibufp++;
1025 			break;
1026 		}
1027 	REALLOC(shcmd, shcmdsz, i + 1, ERR);
1028 	memcpy(shcmd, buf, i);
1029 	shcmd[shcmdi = i] = '\0';
1030 	return *s == '!' || *s == '%';
1031 }
1032 
1033 
1034 /* append_lines: insert text from stdin to after line n; stop when either a
1035    single period is read or EOF; return status */
1036 int
1037 append_lines(n)
1038 	long n;
1039 {
1040 	int l;
1041 	char *lp = ibuf;
1042 	char *eot;
1043 	undo_t *up = NULL;
1044 
1045 	for (current_addr = n;;) {
1046 		if (!isglobal) {
1047 			if ((l = get_tty_line()) < 0)
1048 				return ERR;
1049 			else if (l == 0 || ibuf[l - 1] != '\n') {
1050 				clearerr(stdin);
1051 				return  l ? EOF : 0;
1052 			}
1053 			lp = ibuf;
1054 		} else if (*(lp = ibufp) == '\0')
1055 			return 0;
1056 		else {
1057 			while (*ibufp++ != '\n')
1058 				;
1059 			l = ibufp - lp;
1060 		}
1061 		if (l == 2 && lp[0] == '.' && lp[1] == '\n') {
1062 			return 0;
1063 		}
1064 		eot = lp + l;
1065 		SPL1();
1066 		do {
1067 			if ((lp = put_sbuf_line(lp)) == NULL) {
1068 				SPL0();
1069 				return ERR;
1070 			} else if (up)
1071 				up->t = get_addressed_line_node(current_addr);
1072 			else if ((up = push_undo_stack(UADD, current_addr,
1073 			    current_addr)) == NULL) {
1074 				SPL0();
1075 				return ERR;
1076 			}
1077 		} while (lp != eot);
1078 		modified = 1;
1079 		SPL0();
1080 	}
1081 	/* NOTREACHED */
1082 }
1083 
1084 
1085 /* join_lines: replace a range of lines with the joined text of those lines */
1086 int
1087 join_lines(from, to)
1088 	long from;
1089 	long to;
1090 {
1091 	static char *buf = NULL;
1092 	static int n;
1093 
1094 	char *s;
1095 	int size = 0;
1096 	line_t *bp, *ep;
1097 
1098 	ep = get_addressed_line_node(INC_MOD(to, addr_last));
1099 	bp = get_addressed_line_node(from);
1100 	for (; bp != ep; bp = bp->q_forw) {
1101 		if ((s = get_sbuf_line(bp)) == NULL)
1102 			return ERR;
1103 		REALLOC(buf, n, size + bp->len, ERR);
1104 		memcpy(buf + size, s, bp->len);
1105 		size += bp->len;
1106 	}
1107 	REALLOC(buf, n, size + 2, ERR);
1108 	memcpy(buf + size, "\n", 2);
1109 	if (delete_lines(from, to) < 0)
1110 		return ERR;
1111 	current_addr = from - 1;
1112 	SPL1();
1113 	if (put_sbuf_line(buf) == NULL ||
1114 	    push_undo_stack(UADD, current_addr, current_addr) == NULL) {
1115 		SPL0();
1116 		return ERR;
1117 	}
1118 	modified = 1;
1119 	SPL0();
1120 	return 0;
1121 }
1122 
1123 
1124 /* move_lines: move a range of lines */
1125 int
1126 move_lines(addr)
1127 	long addr;
1128 {
1129 	line_t *b1, *a1, *b2, *a2;
1130 	long n = INC_MOD(second_addr, addr_last);
1131 	long p = first_addr - 1;
1132 	int done = (addr == first_addr - 1 || addr == second_addr);
1133 
1134 	SPL1();
1135 	if (done) {
1136 		a2 = get_addressed_line_node(n);
1137 		b2 = get_addressed_line_node(p);
1138 		current_addr = second_addr;
1139 	} else if (push_undo_stack(UMOV, p, n) == NULL ||
1140 	    push_undo_stack(UMOV, addr, INC_MOD(addr, addr_last)) == NULL) {
1141 		SPL0();
1142 		return ERR;
1143 	} else {
1144 		a1 = get_addressed_line_node(n);
1145 		if (addr < first_addr) {
1146 			b1 = get_addressed_line_node(p);
1147 			b2 = get_addressed_line_node(addr);
1148 					/* this get_addressed_line_node last! */
1149 		} else {
1150 			b2 = get_addressed_line_node(addr);
1151 			b1 = get_addressed_line_node(p);
1152 					/* this get_addressed_line_node last! */
1153 		}
1154 		a2 = b2->q_forw;
1155 		REQUE(b2, b1->q_forw);
1156 		REQUE(a1->q_back, a2);
1157 		REQUE(b1, a1);
1158 		current_addr = addr + ((addr < first_addr) ?
1159 		    second_addr - first_addr + 1 : 0);
1160 	}
1161 	if (isglobal)
1162 		unset_active_nodes(b2->q_forw, a2);
1163 	modified = 1;
1164 	SPL0();
1165 	return 0;
1166 }
1167 
1168 
1169 /* copy_lines: copy a range of lines; return status */
1170 int
1171 copy_lines(addr)
1172 	long addr;
1173 {
1174 	line_t *lp, *np = get_addressed_line_node(first_addr);
1175 	undo_t *up = NULL;
1176 	long n = second_addr - first_addr + 1;
1177 	long m = 0;
1178 
1179 	current_addr = addr;
1180 	if (first_addr <= addr && addr < second_addr) {
1181 		n =  addr - first_addr + 1;
1182 		m = second_addr - addr;
1183 	}
1184 	for (; n > 0; n=m, m=0, np = get_addressed_line_node(current_addr + 1))
1185 		for (; n-- > 0; np = np->q_forw) {
1186 			SPL1();
1187 			if ((lp = dup_line_node(np)) == NULL) {
1188 				SPL0();
1189 				return ERR;
1190 			}
1191 			add_line_node(lp);
1192 			if (up)
1193 				up->t = lp;
1194 			else if ((up = push_undo_stack(UADD, current_addr,
1195 			    current_addr)) == NULL) {
1196 				SPL0();
1197 				return ERR;
1198 			}
1199 			modified = 1;
1200 			SPL0();
1201 		}
1202 	return 0;
1203 }
1204 
1205 
1206 /* delete_lines: delete a range of lines */
1207 int
1208 delete_lines(from, to)
1209 	long from, to;
1210 {
1211 	line_t *n, *p;
1212 
1213 	SPL1();
1214 	if (push_undo_stack(UDEL, from, to) == NULL) {
1215 		SPL0();
1216 		return ERR;
1217 	}
1218 	n = get_addressed_line_node(INC_MOD(to, addr_last));
1219 	p = get_addressed_line_node(from - 1);
1220 					/* this get_addressed_line_node last! */
1221 	if (isglobal)
1222 		unset_active_nodes(p->q_forw, n);
1223 	REQUE(p, n);
1224 	addr_last -= to - from + 1;
1225 	current_addr = from - 1;
1226 	modified = 1;
1227 	SPL0();
1228 	return 0;
1229 }
1230 
1231 
1232 /* display_lines: print a range of lines to stdout */
1233 int
1234 display_lines(from, to, gflag)
1235 	long from;
1236 	long to;
1237 	int gflag;
1238 {
1239 	line_t *bp;
1240 	line_t *ep;
1241 	char *s;
1242 
1243 	if (!from) {
1244 		sprintf(errmsg, "invalid address");
1245 		return ERR;
1246 	}
1247 	ep = get_addressed_line_node(INC_MOD(to, addr_last));
1248 	bp = get_addressed_line_node(from);
1249 	for (; bp != ep; bp = bp->q_forw) {
1250 		if ((s = get_sbuf_line(bp)) == NULL)
1251 			return ERR;
1252 		if (put_tty_line(s, bp->len, current_addr = from++, gflag) < 0)
1253 			return ERR;
1254 	}
1255 	return 0;
1256 }
1257 
1258 
1259 #define MAXMARK 26			/* max number of marks */
1260 
1261 line_t	*mark[MAXMARK];			/* line markers */
1262 int markno;				/* line marker count */
1263 
1264 /* mark_line_node: set a line node mark */
1265 int
1266 mark_line_node(lp, n)
1267 	line_t *lp;
1268 	int n;
1269 {
1270 	if (!islower((unsigned char)n)) {
1271 		sprintf(errmsg, "invalid mark character");
1272 		return ERR;
1273 	} else if (mark[n - 'a'] == NULL)
1274 		markno++;
1275 	mark[n - 'a'] = lp;
1276 	return 0;
1277 }
1278 
1279 
1280 /* get_marked_node_addr: return address of a marked line */
1281 long
1282 get_marked_node_addr(n)
1283 	int n;
1284 {
1285 	if (!islower((unsigned char)n)) {
1286 		sprintf(errmsg, "invalid mark character");
1287 		return ERR;
1288 	}
1289 	return get_line_node_addr(mark[n - 'a']);
1290 }
1291 
1292 
1293 /* unmark_line_node: clear line node mark */
1294 void
1295 unmark_line_node(lp)
1296 	line_t *lp;
1297 {
1298 	int i;
1299 
1300 	for (i = 0; markno && i < MAXMARK; i++)
1301 		if (mark[i] == lp) {
1302 			mark[i] = NULL;
1303 			markno--;
1304 		}
1305 }
1306 
1307 
1308 /* dup_line_node: return a pointer to a copy of a line node */
1309 line_t *
1310 dup_line_node(lp)
1311 	line_t *lp;
1312 {
1313 	line_t *np;
1314 
1315 	if ((np = (line_t *) malloc(sizeof(line_t))) == NULL) {
1316 		fprintf(stderr, "%s\n", strerror(errno));
1317 		sprintf(errmsg, "out of memory");
1318 		return NULL;
1319 	}
1320 	np->seek = lp->seek;
1321 	np->len = lp->len;
1322 	return np;
1323 }
1324 
1325 
1326 /* has_trailing_escape:  return the parity of escapes preceding a character
1327    in a string */
1328 int
1329 has_trailing_escape(s, t)
1330 	char *s;
1331 	char *t;
1332 {
1333     return (s == t || *(t - 1) != '\\') ? 0 : !has_trailing_escape(s, t - 1);
1334 }
1335 
1336 
1337 /* strip_escapes: return copy of escaped string of at most length MAXPATHLEN */
1338 char *
1339 strip_escapes(s)
1340 	char *s;
1341 {
1342 	static char *file = NULL;
1343 	static int filesz = 0;
1344 
1345 	int i = 0;
1346 
1347 	REALLOC(file, filesz, MAXPATHLEN + 1, NULL);
1348 	/* assert: no trailing escape */
1349 	while ((file[i++] = (*s == '\\') ? *++s : *s))
1350 		s++;
1351 	return file;
1352 }
1353 
1354 
1355 void
1356 signal_hup(signo)
1357 	int signo;
1358 {
1359 	if (mutex)
1360 		sigflags |= (1 << (signo - 1));
1361 	else
1362 		handle_hup(signo);
1363 }
1364 
1365 
1366 void
1367 signal_int(signo)
1368 	int signo;
1369 {
1370 	if (mutex)
1371 		sigflags |= (1 << (signo - 1));
1372 	else
1373 		handle_int(signo);
1374 }
1375 
1376 
1377 void
1378 handle_hup(signo)
1379 	int signo;
1380 {
1381 	char *hup = NULL;		/* hup filename */
1382 	char *s;
1383 	int n;
1384 
1385 	if (!sigactive)
1386 		quit(1);
1387 	sigflags &= ~(1 << (signo - 1));
1388 	if (addr_last && write_file("ed.hup", "w", 1, addr_last) < 0 &&
1389 	    (s = getenv("HOME")) != NULL &&
1390 	    (n = strlen(s)) + 8 <= MAXPATHLEN &&	/* "ed.hup" + '/' */
1391 	    (hup = (char *) malloc(n + 10)) != NULL) {
1392 		strcpy(hup, s);
1393 		if (hup[n - 1] != '/')
1394 			hup[n] = '/', hup[n+1] = '\0';
1395 		strcat(hup, "ed.hup");
1396 		write_file(hup, "w", 1, addr_last);
1397 	}
1398 	quit(2);
1399 }
1400 
1401 
1402 void
1403 handle_int(signo)
1404 	int signo;
1405 {
1406 	if (!sigactive)
1407 		quit(1);
1408 	sigflags &= ~(1 << (signo - 1));
1409 #ifdef _POSIX_SOURCE
1410 	siglongjmp(env, -1);
1411 #else
1412 	longjmp(env, -1);
1413 #endif
1414 }
1415 
1416 
1417 int cols = 72;				/* wrap column */
1418 
1419 void
1420 handle_winch(signo)
1421 	int signo;
1422 {
1423 	int save_errno = errno;
1424 
1425 	struct winsize ws;		/* window size structure */
1426 
1427 	sigflags &= ~(1 << (signo - 1));
1428 	if (ioctl(0, TIOCGWINSZ, (char *) &ws) >= 0) {
1429 		if (ws.ws_row > 2) rows = ws.ws_row - 2;
1430 		if (ws.ws_col > 8) cols = ws.ws_col - 8;
1431 	}
1432 	errno = save_errno;
1433 }
1434 
1435 
1436 /* is_legal_filename: return a legal filename */
1437 int
1438 is_legal_filename(s)
1439 	char *s;
1440 {
1441 	if (red && (*s == '!' || !strcmp(s, "..") || strchr(s, '/'))) {
1442 		sprintf(errmsg, "shell access restricted");
1443 		return 0;
1444 	}
1445 	return 1;
1446 }
1447