xref: /dragonfly/bin/ed/main.c (revision cd1c6085)
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  * @(#) Copyright (c) 1993 Andrew Moore, Talke Studio. All rights reserved.
29  * @(#)main.c,v 1.1 1994/02/01 00:34:42 alm Exp
30  * $FreeBSD: head/bin/ed/main.c 241720 2012-10-19 05:43:38Z ed $
31  */
32 
33 /*
34  * CREDITS
35  *
36  *	This program is based on the editor algorithm described in
37  *	Brian W. Kernighan and P. J. Plauger's book "Software Tools
38  *	in Pascal," Addison-Wesley, 1981.
39  *
40  *	The buffering algorithm is attributed to Rodney Ruddock of
41  *	the University of Guelph, Guelph, Ontario.
42  *
43  *	The cbc.c encryption code is adapted from
44  *	the bdes program by Matt Bishop of Dartmouth College,
45  *	Hanover, NH.
46  *
47  */
48 
49 #include <sys/types.h>
50 
51 #include <sys/ioctl.h>
52 #include <sys/wait.h>
53 #include <ctype.h>
54 #include <locale.h>
55 #include <pwd.h>
56 #include <setjmp.h>
57 
58 #include "ed.h"
59 
60 
61 #ifdef _POSIX_SOURCE
62 static sigjmp_buf env;
63 #else
64 static jmp_buf env;
65 #endif
66 
67 /* static buffers */
68 char stdinbuf[1];		/* stdin buffer */
69 static char *shcmd;		/* shell command buffer */
70 static int shcmdsz;		/* shell command buffer size */
71 static int shcmdi;		/* shell command buffer index */
72 char *ibuf;			/* ed command-line buffer */
73 int ibufsz;			/* ed command-line buffer size */
74 char *ibufp;			/* pointer to ed command-line buffer */
75 
76 /* global flags */
77 int des = 0;			/* if set, use crypt(3) for i/o */
78 static int garrulous = 0;	/* if set, print all error messages */
79 int isbinary;			/* if set, buffer contains ASCII NULs */
80 int isglobal;			/* if set, doing a global command */
81 int modified;			/* if set, buffer modified since last write */
82 int mutex = 0;			/* if set, signals set "sigflags" */
83 static int red = 0;		/* if set, restrict shell/directory access */
84 int scripted = 0;		/* if set, suppress diagnostics */
85 int sigflags = 0;		/* if set, signals received while mutex set */
86 static int sigactive = 0;	/* if set, signal handlers are enabled */
87 
88 static char old_filename[PATH_MAX] = ""; /* default filename */
89 long current_addr;		/* current address in editor buffer */
90 long addr_last;			/* last address in editor buffer */
91 int lineno;			/* script line number */
92 static const char *prompt;	/* command-line prompt */
93 static const char *dps = "*";	/* default command-line prompt */
94 
95 static const char *usage = "usage: %s [-] [-sx] [-p string] [file]\n";
96 
97 /* ed: line editor */
98 int
99 main(volatile int argc, char ** volatile argv)
100 {
101 	int c, n;
102 	long status = 0;
103 
104 	setlocale(LC_ALL, "");
105 
106 	red = (n = strlen(argv[0])) > 2 && argv[0][n - 3] == 'r';
107 top:
108 	while ((c = getopt(argc, argv, "p:sx")) != -1)
109 		switch(c) {
110 		case 'p':				/* set prompt */
111 			prompt = optarg;
112 			break;
113 		case 's':				/* run script */
114 			scripted = 1;
115 			break;
116 		case 'x':				/* use crypt */
117 #ifdef DES
118 			des = get_keyword();
119 #else
120 			fprintf(stderr, "crypt unavailable\n?\n");
121 #endif
122 			break;
123 
124 		default:
125 			fprintf(stderr, usage, red ? "red" : "ed");
126 			exit(1);
127 		}
128 	argv += optind;
129 	argc -= optind;
130 	if (argc && **argv == '-') {
131 		scripted = 1;
132 		if (argc > 1) {
133 			optind = 1;
134 			goto top;
135 		}
136 		argv++;
137 		argc--;
138 	}
139 	/* assert: reliable signals! */
140 #ifdef SIGWINCH
141 	handle_winch(SIGWINCH);
142 	if (isatty(0)) signal(SIGWINCH, handle_winch);
143 #endif
144 	signal(SIGHUP, signal_hup);
145 	signal(SIGQUIT, SIG_IGN);
146 	signal(SIGINT, signal_int);
147 #ifdef _POSIX_SOURCE
148 	if ((status = sigsetjmp(env, 1)))
149 #else
150 	if ((status = setjmp(env)))
151 #endif
152 	{
153 		fputs("\n?\n", stderr);
154 		errmsg = "interrupt";
155 	} else {
156 		init_buffers();
157 		sigactive = 1;			/* enable signal handlers */
158 		if (argc && **argv && is_legal_filename(*argv)) {
159 			if (read_file(*argv, 0) < 0 && !isatty(0))
160 				quit(2);
161 			else if (**argv != '!')
162 				if (strlcpy(old_filename, *argv, sizeof(old_filename))
163 				    >= sizeof(old_filename))
164 					quit(2);
165 		} else if (argc) {
166 			fputs("?\n", stderr);
167 			if (**argv == '\0')
168 				errmsg = "invalid filename";
169 			if (!isatty(0))
170 				quit(2);
171 		}
172 	}
173 	for (;;) {
174 		if (status < 0 && garrulous)
175 			fprintf(stderr, "%s\n", errmsg);
176 		if (prompt) {
177 			printf("%s", prompt);
178 			fflush(stdout);
179 		}
180 		if ((n = get_tty_line()) < 0) {
181 			status = ERR;
182 			continue;
183 		} else if (n == 0) {
184 			if (modified && !scripted) {
185 				fputs("?\n", stderr);
186 				errmsg = "warning: file modified";
187 				if (!isatty(0)) {
188 					if (garrulous)
189 						fprintf(stderr,
190 						    "script, line %d: %s\n",
191 						    lineno, errmsg);
192 					quit(2);
193 				}
194 				clearerr(stdin);
195 				modified = 0;
196 				status = EMOD;
197 				continue;
198 			} else
199 				quit(0);
200 		} else if (ibuf[n - 1] != '\n') {
201 			/* discard line */
202 			errmsg = "unexpected end-of-file";
203 			clearerr(stdin);
204 			status = ERR;
205 			continue;
206 		}
207 		isglobal = 0;
208 		if ((status = extract_addr_range()) >= 0 &&
209 		    (status = exec_command()) >= 0)
210 			if (!status ||
211 			    (status = display_lines(current_addr, current_addr,
212 			        status)) >= 0)
213 				continue;
214 		switch (status) {
215 		case EOF:
216 			quit(0);
217 		case EMOD:
218 			modified = 0;
219 			fputs("?\n", stderr);		/* give warning */
220 			errmsg = "warning: file modified";
221 			if (!isatty(0)) {
222 				if (garrulous)
223 					fprintf(stderr, "script, line %d: %s\n",
224 					    lineno, errmsg);
225 				quit(2);
226 			}
227 			break;
228 		case FATAL:
229 			if (!isatty(0)) {
230 				if (garrulous)
231 					fprintf(stderr, "script, line %d: %s\n",
232 					    lineno, errmsg);
233 			} else if (garrulous)
234 				fprintf(stderr, "%s\n", errmsg);
235 			quit(3);
236 		default:
237 			fputs("?\n", stderr);
238 			if (!isatty(0)) {
239 				if (garrulous)
240 					fprintf(stderr, "script, line %d: %s\n",
241 					    lineno, errmsg);
242 				quit(2);
243 			}
244 			break;
245 		}
246 	}
247 	/*NOTREACHED*/
248 }
249 
250 long first_addr, second_addr;
251 static long addr_cnt;
252 
253 /* extract_addr_range: get line addresses from the command buffer until an
254    illegal address is seen; return status */
255 int
256 extract_addr_range(void)
257 {
258 	long addr;
259 
260 	addr_cnt = 0;
261 	first_addr = second_addr = current_addr;
262 	while ((addr = next_addr()) >= 0) {
263 		addr_cnt++;
264 		first_addr = second_addr;
265 		second_addr = addr;
266 		if (*ibufp != ',' && *ibufp != ';')
267 			break;
268 		else if (*ibufp++ == ';')
269 			current_addr = addr;
270 	}
271 	if ((addr_cnt = min(addr_cnt, 2)) == 1 || second_addr != addr)
272 		first_addr = second_addr;
273 	return (addr == ERR) ? ERR : 0;
274 }
275 
276 
277 #define SKIP_BLANKS() while (isspace((unsigned char)*ibufp) && *ibufp != '\n') ibufp++
278 
279 #define MUST_BE_FIRST() do {					\
280 	if (!first) {						\
281 		errmsg = "invalid address";			\
282 		return ERR;					\
283 	}							\
284 } while (0)
285 
286 /*  next_addr: return the next line address in the command buffer */
287 long
288 next_addr(void)
289 {
290 	const char *hd;
291 	long addr = current_addr;
292 	long n;
293 	int first = 1;
294 	int c;
295 
296 	SKIP_BLANKS();
297 	for (hd = ibufp;; first = 0)
298 		switch (c = *ibufp) {
299 		case '+':
300 		case '\t':
301 		case ' ':
302 		case '-':
303 		case '^':
304 			ibufp++;
305 			SKIP_BLANKS();
306 			if (isdigit((unsigned char)*ibufp)) {
307 				STRTOL(n, ibufp);
308 				addr += (c == '-' || c == '^') ? -n : n;
309 			} else if (!isspace((unsigned char)c))
310 				addr += (c == '-' || c == '^') ? -1 : 1;
311 			break;
312 		case '0': case '1': case '2':
313 		case '3': case '4': case '5':
314 		case '6': case '7': case '8': case '9':
315 			MUST_BE_FIRST();
316 			STRTOL(addr, ibufp);
317 			break;
318 		case '.':
319 		case '$':
320 			MUST_BE_FIRST();
321 			ibufp++;
322 			addr = (c == '.') ? current_addr : addr_last;
323 			break;
324 		case '/':
325 		case '?':
326 			MUST_BE_FIRST();
327 			if ((addr = get_matching_node_addr(
328 			    get_compiled_pattern(), c == '/')) < 0)
329 				return ERR;
330 			else if (c == *ibufp)
331 				ibufp++;
332 			break;
333 		case '\'':
334 			MUST_BE_FIRST();
335 			ibufp++;
336 			if ((addr = get_marked_node_addr(*ibufp++)) < 0)
337 				return ERR;
338 			break;
339 		case '%':
340 		case ',':
341 		case ';':
342 			if (first) {
343 				ibufp++;
344 				addr_cnt++;
345 				second_addr = (c == ';') ? current_addr : 1;
346 				addr = addr_last;
347 				break;
348 			}
349 			/* FALLTHROUGH */
350 		default:
351 			if (ibufp == hd)
352 				return EOF;
353 			else if (addr < 0 || addr_last < addr) {
354 				errmsg = "invalid address";
355 				return ERR;
356 			} else
357 				return addr;
358 		}
359 	/* NOTREACHED */
360 }
361 
362 
363 #ifdef BACKWARDS
364 /* GET_THIRD_ADDR: get a legal address from the command buffer */
365 #define GET_THIRD_ADDR(addr) \
366 { \
367 	long ol1, ol2; \
368 \
369 	ol1 = first_addr, ol2 = second_addr; \
370 	if (extract_addr_range() < 0) \
371 		return ERR; \
372 	else if (addr_cnt == 0) { \
373 		errmsg = "destination expected"; \
374 		return ERR; \
375 	} else if (second_addr < 0 || addr_last < second_addr) { \
376 		errmsg = "invalid address"; \
377 		return ERR; \
378 	} \
379 	addr = second_addr; \
380 	first_addr = ol1, second_addr = ol2; \
381 }
382 #else	/* BACKWARDS */
383 /* GET_THIRD_ADDR: get a legal address from the command buffer */
384 #define GET_THIRD_ADDR(addr) \
385 { \
386 	long ol1, ol2; \
387 \
388 	ol1 = first_addr, ol2 = second_addr; \
389 	if (extract_addr_range() < 0) \
390 		return ERR; \
391 	if (second_addr < 0 || addr_last < second_addr) { \
392 		errmsg = "invalid address"; \
393 		return ERR; \
394 	} \
395 	addr = second_addr; \
396 	first_addr = ol1, second_addr = ol2; \
397 }
398 #endif
399 
400 
401 /* GET_COMMAND_SUFFIX: verify the command suffix in the command buffer */
402 #define GET_COMMAND_SUFFIX() { \
403 	int done = 0; \
404 	do { \
405 		switch(*ibufp) { \
406 		case 'p': \
407 			gflag |= GPR, ibufp++; \
408 			break; \
409 		case 'l': \
410 			gflag |= GLS, ibufp++; \
411 			break; \
412 		case 'n': \
413 			gflag |= GNP, ibufp++; \
414 			break; \
415 		default: \
416 			done++; \
417 		} \
418 	} while (!done); \
419 	if (*ibufp++ != '\n') { \
420 		errmsg = "invalid command suffix"; \
421 		return ERR; \
422 	} \
423 }
424 
425 
426 /* sflags */
427 #define SGG 001		/* complement previous global substitute suffix */
428 #define SGP 002		/* complement previous print suffix */
429 #define SGR 004		/* use last regex instead of last pat */
430 #define SGF 010		/* repeat last substitution */
431 
432 int patlock = 0;	/* if set, pattern not freed by get_compiled_pattern() */
433 
434 long rows = 22;		/* scroll length: ws_row - 2 */
435 
436 /* exec_command: execute the next command in command buffer; return print
437    request, if any */
438 int
439 exec_command(void)
440 {
441 	static pattern_t *pat = NULL;
442 	static int sgflag = 0;
443 	static long sgnum = 0;
444 
445 	pattern_t *tpat;
446 	char *fnp;
447 	int gflag = 0;
448 	int sflags = 0;
449 	long addr = 0;
450 	int n = 0;
451 	int c;
452 
453 	SKIP_BLANKS();
454 	switch(c = *ibufp++) {
455 	case 'a':
456 		GET_COMMAND_SUFFIX();
457 		if (!isglobal) clear_undo_stack();
458 		if (append_lines(second_addr) < 0)
459 			return ERR;
460 		break;
461 	case 'c':
462 		if (check_addr_range(current_addr, current_addr) < 0)
463 			return ERR;
464 		GET_COMMAND_SUFFIX();
465 		if (!isglobal) clear_undo_stack();
466 		if (delete_lines(first_addr, second_addr) < 0 ||
467 		    append_lines(current_addr) < 0)
468 			return ERR;
469 		break;
470 	case 'd':
471 		if (check_addr_range(current_addr, current_addr) < 0)
472 			return ERR;
473 		GET_COMMAND_SUFFIX();
474 		if (!isglobal) clear_undo_stack();
475 		if (delete_lines(first_addr, second_addr) < 0)
476 			return ERR;
477 		else if ((addr = INC_MOD(current_addr, addr_last)) != 0)
478 			current_addr = addr;
479 		break;
480 	case 'e':
481 		if (modified && !scripted)
482 			return EMOD;
483 		/* FALLTHROUGH */
484 	case 'E':
485 		if (addr_cnt > 0) {
486 			errmsg = "unexpected address";
487 			return ERR;
488 		} else if (!isspace((unsigned char)*ibufp)) {
489 			errmsg = "unexpected command suffix";
490 			return ERR;
491 		} else if ((fnp = get_filename()) == NULL)
492 			return ERR;
493 		GET_COMMAND_SUFFIX();
494 		if (delete_lines(1, addr_last) < 0)
495 			return ERR;
496 		clear_undo_stack();
497 		if (close_sbuf() < 0)
498 			return ERR;
499 		else if (open_sbuf() < 0)
500 			return FATAL;
501 		if (*fnp && *fnp != '!') strcpy(old_filename, fnp);
502 #ifdef BACKWARDS
503 		if (*fnp == '\0' && *old_filename == '\0') {
504 			errmsg = "no current filename";
505 			return ERR;
506 		}
507 #endif
508 		if (read_file(*fnp ? fnp : old_filename, 0) < 0)
509 			return ERR;
510 		clear_undo_stack();
511 		modified = 0;
512 		u_current_addr = u_addr_last = -1;
513 		break;
514 	case 'f':
515 		if (addr_cnt > 0) {
516 			errmsg = "unexpected address";
517 			return ERR;
518 		} else if (!isspace((unsigned char)*ibufp)) {
519 			errmsg = "unexpected command suffix";
520 			return ERR;
521 		} else if ((fnp = get_filename()) == NULL)
522 			return ERR;
523 		else if (*fnp == '!') {
524 			errmsg = "invalid redirection";
525 			return ERR;
526 		}
527 		GET_COMMAND_SUFFIX();
528 		if (*fnp) strcpy(old_filename, fnp);
529 		printf("%s\n", strip_escapes(old_filename));
530 		break;
531 	case 'g':
532 	case 'v':
533 	case 'G':
534 	case 'V':
535 		if (isglobal) {
536 			errmsg = "cannot nest global commands";
537 			return ERR;
538 		} else if (check_addr_range(1, addr_last) < 0)
539 			return ERR;
540 		else if (build_active_list(c == 'g' || c == 'G') < 0)
541 			return ERR;
542 		else if ((n = (c == 'G' || c == 'V')))
543 			GET_COMMAND_SUFFIX();
544 		isglobal++;
545 		if (exec_global(n, gflag) < 0)
546 			return ERR;
547 		break;
548 	case 'h':
549 		if (addr_cnt > 0) {
550 			errmsg = "unexpected address";
551 			return ERR;
552 		}
553 		GET_COMMAND_SUFFIX();
554 		if (*errmsg) fprintf(stderr, "%s\n", errmsg);
555 		break;
556 	case 'H':
557 		if (addr_cnt > 0) {
558 			errmsg = "unexpected address";
559 			return ERR;
560 		}
561 		GET_COMMAND_SUFFIX();
562 		if ((garrulous = 1 - garrulous) && *errmsg)
563 			fprintf(stderr, "%s\n", errmsg);
564 		break;
565 	case 'i':
566 		if (second_addr == 0) {
567 			errmsg = "invalid address";
568 			return ERR;
569 		}
570 		GET_COMMAND_SUFFIX();
571 		if (!isglobal) clear_undo_stack();
572 		if (append_lines(second_addr - 1) < 0)
573 			return ERR;
574 		break;
575 	case 'j':
576 		if (check_addr_range(current_addr, current_addr + 1) < 0)
577 			return ERR;
578 		GET_COMMAND_SUFFIX();
579 		if (!isglobal) clear_undo_stack();
580 		if (first_addr != second_addr &&
581 		    join_lines(first_addr, second_addr) < 0)
582 			return ERR;
583 		break;
584 	case 'k':
585 		c = *ibufp++;
586 		if (second_addr == 0) {
587 			errmsg = "invalid address";
588 			return ERR;
589 		}
590 		GET_COMMAND_SUFFIX();
591 		if (mark_line_node(get_addressed_line_node(second_addr), c) < 0)
592 			return ERR;
593 		break;
594 	case 'l':
595 		if (check_addr_range(current_addr, current_addr) < 0)
596 			return ERR;
597 		GET_COMMAND_SUFFIX();
598 		if (display_lines(first_addr, second_addr, gflag | GLS) < 0)
599 			return ERR;
600 		gflag = 0;
601 		break;
602 	case 'm':
603 		if (check_addr_range(current_addr, current_addr) < 0)
604 			return ERR;
605 		GET_THIRD_ADDR(addr);
606 		if (first_addr <= addr && addr < second_addr) {
607 			errmsg = "invalid destination";
608 			return ERR;
609 		}
610 		GET_COMMAND_SUFFIX();
611 		if (!isglobal) clear_undo_stack();
612 		if (move_lines(addr) < 0)
613 			return ERR;
614 		break;
615 	case 'n':
616 		if (check_addr_range(current_addr, current_addr) < 0)
617 			return ERR;
618 		GET_COMMAND_SUFFIX();
619 		if (display_lines(first_addr, second_addr, gflag | GNP) < 0)
620 			return ERR;
621 		gflag = 0;
622 		break;
623 	case 'p':
624 		if (check_addr_range(current_addr, current_addr) < 0)
625 			return ERR;
626 		GET_COMMAND_SUFFIX();
627 		if (display_lines(first_addr, second_addr, gflag | GPR) < 0)
628 			return ERR;
629 		gflag = 0;
630 		break;
631 	case 'P':
632 		if (addr_cnt > 0) {
633 			errmsg = "unexpected address";
634 			return ERR;
635 		}
636 		GET_COMMAND_SUFFIX();
637 		prompt = prompt ? NULL : optarg ? optarg : dps;
638 		break;
639 	case 'q':
640 	case 'Q':
641 		if (addr_cnt > 0) {
642 			errmsg = "unexpected address";
643 			return ERR;
644 		}
645 		GET_COMMAND_SUFFIX();
646 		gflag =  (modified && !scripted && c == 'q') ? EMOD : EOF;
647 		break;
648 	case 'r':
649 		if (!isspace((unsigned char)*ibufp)) {
650 			errmsg = "unexpected command suffix";
651 			return ERR;
652 		} else if (addr_cnt == 0)
653 			second_addr = addr_last;
654 		if ((fnp = get_filename()) == NULL)
655 			return ERR;
656 		GET_COMMAND_SUFFIX();
657 		if (!isglobal) clear_undo_stack();
658 		if (*old_filename == '\0' && *fnp != '!')
659 			strcpy(old_filename, fnp);
660 #ifdef BACKWARDS
661 		if (*fnp == '\0' && *old_filename == '\0') {
662 			errmsg = "no current filename";
663 			return ERR;
664 		}
665 #endif
666 		if ((addr = read_file(*fnp ? fnp : old_filename, second_addr)) < 0)
667 			return ERR;
668 		else if (addr && addr != addr_last)
669 			modified = 1;
670 		break;
671 	case 's':
672 		do {
673 			switch(*ibufp) {
674 			case '\n':
675 				sflags |=SGF;
676 				break;
677 			case 'g':
678 				sflags |= SGG;
679 				ibufp++;
680 				break;
681 			case 'p':
682 				sflags |= SGP;
683 				ibufp++;
684 				break;
685 			case 'r':
686 				sflags |= SGR;
687 				ibufp++;
688 				break;
689 			case '0': case '1': case '2': case '3': case '4':
690 			case '5': case '6': case '7': case '8': case '9':
691 				STRTOL(sgnum, ibufp);
692 				sflags |= SGF;
693 				sgflag &= ~GSG;		/* override GSG */
694 				break;
695 			default:
696 				if (sflags) {
697 					errmsg = "invalid command suffix";
698 					return ERR;
699 				}
700 			}
701 		} while (sflags && *ibufp != '\n');
702 		if (sflags && !pat) {
703 			errmsg = "no previous substitution";
704 			return ERR;
705 		} else if (sflags & SGG)
706 			sgnum = 0;		/* override numeric arg */
707 		if (*ibufp != '\n' && *(ibufp + 1) == '\n') {
708 			errmsg = "invalid pattern delimiter";
709 			return ERR;
710 		}
711 		tpat = pat;
712 		SPL1();
713 		if ((!sflags || (sflags & SGR)) &&
714 		    (tpat = get_compiled_pattern()) == NULL) {
715 		 	SPL0();
716 			return ERR;
717 		} else if (tpat != pat) {
718 			if (pat) {
719 				regfree(pat);
720 				free(pat);
721 			}
722 			pat = tpat;
723 			patlock = 1;		/* reserve pattern */
724 		}
725 		SPL0();
726 		if (!sflags && extract_subst_tail(&sgflag, &sgnum) < 0)
727 			return ERR;
728 		else if (isglobal)
729 			sgflag |= GLB;
730 		else
731 			sgflag &= ~GLB;
732 		if (sflags & SGG)
733 			sgflag ^= GSG;
734 		if (sflags & SGP)
735 			sgflag ^= GPR, sgflag &= ~(GLS | GNP);
736 		do {
737 			switch(*ibufp) {
738 			case 'p':
739 				sgflag |= GPR, ibufp++;
740 				break;
741 			case 'l':
742 				sgflag |= GLS, ibufp++;
743 				break;
744 			case 'n':
745 				sgflag |= GNP, ibufp++;
746 				break;
747 			default:
748 				n++;
749 			}
750 		} while (!n);
751 		if (check_addr_range(current_addr, current_addr) < 0)
752 			return ERR;
753 		GET_COMMAND_SUFFIX();
754 		if (!isglobal) clear_undo_stack();
755 		if (search_and_replace(pat, sgflag, sgnum) < 0)
756 			return ERR;
757 		break;
758 	case 't':
759 		if (check_addr_range(current_addr, current_addr) < 0)
760 			return ERR;
761 		GET_THIRD_ADDR(addr);
762 		GET_COMMAND_SUFFIX();
763 		if (!isglobal) clear_undo_stack();
764 		if (copy_lines(addr) < 0)
765 			return ERR;
766 		break;
767 	case 'u':
768 		if (addr_cnt > 0) {
769 			errmsg = "unexpected address";
770 			return ERR;
771 		}
772 		GET_COMMAND_SUFFIX();
773 		if (pop_undo_stack() < 0)
774 			return ERR;
775 		break;
776 	case 'w':
777 	case 'W':
778 		if ((n = *ibufp) == 'q' || n == 'Q') {
779 			gflag = EOF;
780 			ibufp++;
781 		}
782 		if (!isspace((unsigned char)*ibufp)) {
783 			errmsg = "unexpected command suffix";
784 			return ERR;
785 		} else if ((fnp = get_filename()) == NULL)
786 			return ERR;
787 		if (addr_cnt == 0 && !addr_last)
788 			first_addr = second_addr = 0;
789 		else if (check_addr_range(1, addr_last) < 0)
790 			return ERR;
791 		GET_COMMAND_SUFFIX();
792 		if (*old_filename == '\0' && *fnp != '!')
793 			strcpy(old_filename, fnp);
794 #ifdef BACKWARDS
795 		if (*fnp == '\0' && *old_filename == '\0') {
796 			errmsg = "no current filename";
797 			return ERR;
798 		}
799 #endif
800 		if ((addr = write_file(*fnp ? fnp : old_filename,
801 		    (c == 'W') ? "a" : "w", first_addr, second_addr)) < 0)
802 			return ERR;
803 		else if (addr == addr_last)
804 			modified = 0;
805 		else if (modified && !scripted && n == 'q')
806 			gflag = EMOD;
807 		break;
808 	case 'x':
809 		if (addr_cnt > 0) {
810 			errmsg = "unexpected address";
811 			return ERR;
812 		}
813 		GET_COMMAND_SUFFIX();
814 #ifdef DES
815 		des = get_keyword();
816 		break;
817 #else
818 		errmsg = "crypt unavailable";
819 		return ERR;
820 #endif
821 	case 'z':
822 #ifdef BACKWARDS
823 		if (check_addr_range(first_addr = 1, current_addr + 1) < 0)
824 #else
825 		if (check_addr_range(first_addr = 1, current_addr + !isglobal) < 0)
826 #endif
827 			return ERR;
828 		else if ('0' < *ibufp && *ibufp <= '9')
829 			STRTOL(rows, ibufp);
830 		GET_COMMAND_SUFFIX();
831 		if (display_lines(second_addr, min(addr_last,
832 		    second_addr + rows), gflag) < 0)
833 			return ERR;
834 		gflag = 0;
835 		break;
836 	case '=':
837 		GET_COMMAND_SUFFIX();
838 		printf("%ld\n", addr_cnt ? second_addr : addr_last);
839 		break;
840 	case '!':
841 		if (addr_cnt > 0) {
842 			errmsg = "unexpected address";
843 			return ERR;
844 		} else if ((sflags = get_shell_command()) < 0)
845 			return ERR;
846 		GET_COMMAND_SUFFIX();
847 		if (sflags) printf("%s\n", shcmd + 1);
848 		system(shcmd + 1);
849 		if (!scripted) printf("!\n");
850 		break;
851 	case '\n':
852 #ifdef BACKWARDS
853 		if (check_addr_range(first_addr = 1, current_addr + 1) < 0
854 #else
855 		if (check_addr_range(first_addr = 1, current_addr + !isglobal) < 0
856 #endif
857 		 || display_lines(second_addr, second_addr, 0) < 0)
858 			return ERR;
859 		break;
860 	default:
861 		errmsg = "unknown command";
862 		return ERR;
863 	}
864 	return gflag;
865 }
866 
867 
868 /* check_addr_range: return status of address range check */
869 int
870 check_addr_range(long n, long m)
871 {
872 	if (addr_cnt == 0) {
873 		first_addr = n;
874 		second_addr = m;
875 	}
876 	if (first_addr > second_addr || 1 > first_addr ||
877 	    second_addr > addr_last) {
878 		errmsg = "invalid address";
879 		return ERR;
880 	}
881 	return 0;
882 }
883 
884 
885 /* get_matching_node_addr: return the address of the next line matching a
886    pattern in a given direction.  wrap around begin/end of editor buffer if
887    necessary */
888 long
889 get_matching_node_addr(pattern_t *pat, int dir)
890 {
891 	char *s;
892 	long n = current_addr;
893 	line_t *lp;
894 
895 	if (!pat) return ERR;
896 	do {
897 	       if ((n = dir ? INC_MOD(n, addr_last) : DEC_MOD(n, addr_last))) {
898 			lp = get_addressed_line_node(n);
899 			if ((s = get_sbuf_line(lp)) == NULL)
900 				return ERR;
901 			if (isbinary)
902 				NUL_TO_NEWLINE(s, lp->len);
903 			if (!regexec(pat, s, 0, NULL, 0))
904 				return n;
905 	       }
906 	} while (n != current_addr);
907 	errmsg = "no match";
908 	return  ERR;
909 }
910 
911 
912 /* get_filename: return pointer to copy of filename in the command buffer */
913 char *
914 get_filename(void)
915 {
916 	static char *file = NULL;
917 	static int filesz = 0;
918 
919 	int n;
920 
921 	if (*ibufp != '\n') {
922 		SKIP_BLANKS();
923 		if (*ibufp == '\n') {
924 			errmsg = "invalid filename";
925 			return NULL;
926 		} else if ((ibufp = get_extended_line(&n, 1)) == NULL)
927 			return NULL;
928 		else if (*ibufp == '!') {
929 			ibufp++;
930 			if ((n = get_shell_command()) < 0)
931 				return NULL;
932 			if (n)
933 				printf("%s\n", shcmd + 1);
934 			return shcmd;
935 		} else if (n > PATH_MAX - 1) {
936 			errmsg = "filename too long";
937 			return  NULL;
938 		}
939 	}
940 #ifndef BACKWARDS
941 	else if (*old_filename == '\0') {
942 		errmsg = "no current filename";
943 		return  NULL;
944 	}
945 #endif
946 	REALLOC(file, filesz, PATH_MAX, NULL);
947 	for (n = 0; *ibufp != '\n';)
948 		file[n++] = *ibufp++;
949 	file[n] = '\0';
950 	return is_legal_filename(file) ? file : NULL;
951 }
952 
953 
954 /* get_shell_command: read a shell command from stdin; return substitution
955    status */
956 int
957 get_shell_command(void)
958 {
959 	static char *buf = NULL;
960 	static int n = 0;
961 
962 	char *s;			/* substitution char pointer */
963 	int i = 0;
964 	int j = 0;
965 
966 	if (red) {
967 		errmsg = "shell access restricted";
968 		return ERR;
969 	} else if ((s = ibufp = get_extended_line(&j, 1)) == NULL)
970 		return ERR;
971 	REALLOC(buf, n, j + 1, ERR);
972 	buf[i++] = '!';			/* prefix command w/ bang */
973 	while (*ibufp != '\n')
974 		switch (*ibufp) {
975 		default:
976 			REALLOC(buf, n, i + 2, ERR);
977 			buf[i++] = *ibufp;
978 			if (*ibufp++ == '\\')
979 				buf[i++] = *ibufp++;
980 			break;
981 		case '!':
982 			if (s != ibufp) {
983 				REALLOC(buf, n, i + 1, ERR);
984 				buf[i++] = *ibufp++;
985 			}
986 #ifdef BACKWARDS
987 			else if (shcmd == NULL || *(shcmd + 1) == '\0')
988 #else
989 			else if (shcmd == NULL)
990 #endif
991 			{
992 				errmsg = "no previous command";
993 				return ERR;
994 			} else {
995 				REALLOC(buf, n, i + shcmdi, ERR);
996 				for (s = shcmd + 1; s < shcmd + shcmdi;)
997 					buf[i++] = *s++;
998 				s = ibufp++;
999 			}
1000 			break;
1001 		case '%':
1002 			if (*old_filename  == '\0') {
1003 				errmsg = "no current filename";
1004 				return ERR;
1005 			}
1006 			j = strlen(s = strip_escapes(old_filename));
1007 			REALLOC(buf, n, i + j, ERR);
1008 			while (j--)
1009 				buf[i++] = *s++;
1010 			s = ibufp++;
1011 			break;
1012 		}
1013 	REALLOC(shcmd, shcmdsz, i + 1, ERR);
1014 	memcpy(shcmd, buf, i);
1015 	shcmd[shcmdi = i] = '\0';
1016 	return *s == '!' || *s == '%';
1017 }
1018 
1019 
1020 /* append_lines: insert text from stdin to after line n; stop when either a
1021    single period is read or EOF; return status */
1022 int
1023 append_lines(long n)
1024 {
1025 	int l;
1026 	const char *lp = ibuf;
1027 	const char *eot;
1028 	undo_t *up = NULL;
1029 
1030 	for (current_addr = n;;) {
1031 		if (!isglobal) {
1032 			if ((l = get_tty_line()) < 0)
1033 				return ERR;
1034 			else if (l == 0 || ibuf[l - 1] != '\n') {
1035 				clearerr(stdin);
1036 				return  l ? EOF : 0;
1037 			}
1038 			lp = ibuf;
1039 		} else if (*(lp = ibufp) == '\0')
1040 			return 0;
1041 		else {
1042 			while (*ibufp++ != '\n')
1043 				;
1044 			l = ibufp - lp;
1045 		}
1046 		if (l == 2 && lp[0] == '.' && lp[1] == '\n') {
1047 			return 0;
1048 		}
1049 		eot = lp + l;
1050 		SPL1();
1051 		do {
1052 			if ((lp = put_sbuf_line(lp)) == NULL) {
1053 				SPL0();
1054 				return ERR;
1055 			} else if (up)
1056 				up->t = get_addressed_line_node(current_addr);
1057 			else if ((up = push_undo_stack(UADD, current_addr,
1058 			    current_addr)) == NULL) {
1059 				SPL0();
1060 				return ERR;
1061 			}
1062 		} while (lp != eot);
1063 		modified = 1;
1064 		SPL0();
1065 	}
1066 	/* NOTREACHED */
1067 }
1068 
1069 
1070 /* join_lines: replace a range of lines with the joined text of those lines */
1071 int
1072 join_lines(long from, long to)
1073 {
1074 	static char *buf = NULL;
1075 	static int n;
1076 
1077 	char *s;
1078 	int size = 0;
1079 	line_t *bp, *ep;
1080 
1081 	ep = get_addressed_line_node(INC_MOD(to, addr_last));
1082 	bp = get_addressed_line_node(from);
1083 	for (; bp != ep; bp = bp->q_forw) {
1084 		if ((s = get_sbuf_line(bp)) == NULL)
1085 			return ERR;
1086 		REALLOC(buf, n, size + bp->len, ERR);
1087 		memcpy(buf + size, s, bp->len);
1088 		size += bp->len;
1089 	}
1090 	REALLOC(buf, n, size + 2, ERR);
1091 	memcpy(buf + size, "\n", 2);
1092 	if (delete_lines(from, to) < 0)
1093 		return ERR;
1094 	current_addr = from - 1;
1095 	SPL1();
1096 	if (put_sbuf_line(buf) == NULL ||
1097 	    push_undo_stack(UADD, current_addr, current_addr) == NULL) {
1098 		SPL0();
1099 		return ERR;
1100 	}
1101 	modified = 1;
1102 	SPL0();
1103 	return 0;
1104 }
1105 
1106 
1107 /* move_lines: move a range of lines */
1108 int
1109 move_lines(long addr)
1110 {
1111 	line_t *b1, *a1, *b2, *a2;
1112 	long n = INC_MOD(second_addr, addr_last);
1113 	long p = first_addr - 1;
1114 	int done = (addr == first_addr - 1 || addr == second_addr);
1115 
1116 	SPL1();
1117 	if (done) {
1118 		a2 = get_addressed_line_node(n);
1119 		b2 = get_addressed_line_node(p);
1120 		current_addr = second_addr;
1121 	} else if (push_undo_stack(UMOV, p, n) == NULL ||
1122 	    push_undo_stack(UMOV, addr, INC_MOD(addr, addr_last)) == NULL) {
1123 		SPL0();
1124 		return ERR;
1125 	} else {
1126 		a1 = get_addressed_line_node(n);
1127 		if (addr < first_addr) {
1128 			b1 = get_addressed_line_node(p);
1129 			b2 = get_addressed_line_node(addr);
1130 					/* this get_addressed_line_node last! */
1131 		} else {
1132 			b2 = get_addressed_line_node(addr);
1133 			b1 = get_addressed_line_node(p);
1134 					/* this get_addressed_line_node last! */
1135 		}
1136 		a2 = b2->q_forw;
1137 		REQUE(b2, b1->q_forw);
1138 		REQUE(a1->q_back, a2);
1139 		REQUE(b1, a1);
1140 		current_addr = addr + ((addr < first_addr) ?
1141 		    second_addr - first_addr + 1 : 0);
1142 	}
1143 	if (isglobal)
1144 		unset_active_nodes(b2->q_forw, a2);
1145 	modified = 1;
1146 	SPL0();
1147 	return 0;
1148 }
1149 
1150 
1151 /* copy_lines: copy a range of lines; return status */
1152 int
1153 copy_lines(long addr)
1154 {
1155 	line_t *lp, *np = get_addressed_line_node(first_addr);
1156 	undo_t *up = NULL;
1157 	long n = second_addr - first_addr + 1;
1158 	long m = 0;
1159 
1160 	current_addr = addr;
1161 	if (first_addr <= addr && addr < second_addr) {
1162 		n =  addr - first_addr + 1;
1163 		m = second_addr - addr;
1164 	}
1165 	for (; n > 0; n=m, m=0, np = get_addressed_line_node(current_addr + 1))
1166 		for (; n-- > 0; np = np->q_forw) {
1167 			SPL1();
1168 			if ((lp = dup_line_node(np)) == NULL) {
1169 				SPL0();
1170 				return ERR;
1171 			}
1172 			add_line_node(lp);
1173 			if (up)
1174 				up->t = lp;
1175 			else if ((up = push_undo_stack(UADD, current_addr,
1176 			    current_addr)) == NULL) {
1177 				SPL0();
1178 				return ERR;
1179 			}
1180 			modified = 1;
1181 			SPL0();
1182 		}
1183 	return 0;
1184 }
1185 
1186 
1187 /* delete_lines: delete a range of lines */
1188 int
1189 delete_lines(long from, long to)
1190 {
1191 	line_t *n, *p;
1192 
1193 	SPL1();
1194 	if (push_undo_stack(UDEL, from, to) == NULL) {
1195 		SPL0();
1196 		return ERR;
1197 	}
1198 	n = get_addressed_line_node(INC_MOD(to, addr_last));
1199 	p = get_addressed_line_node(from - 1);
1200 					/* this get_addressed_line_node last! */
1201 	if (isglobal)
1202 		unset_active_nodes(p->q_forw, n);
1203 	REQUE(p, n);
1204 	addr_last -= to - from + 1;
1205 	current_addr = from - 1;
1206 	modified = 1;
1207 	SPL0();
1208 	return 0;
1209 }
1210 
1211 
1212 /* display_lines: print a range of lines to stdout */
1213 int
1214 display_lines(long from, long to, int gflag)
1215 {
1216 	line_t *bp;
1217 	line_t *ep;
1218 	char *s;
1219 
1220 	if (!from) {
1221 		errmsg = "invalid address";
1222 		return ERR;
1223 	}
1224 	ep = get_addressed_line_node(INC_MOD(to, addr_last));
1225 	bp = get_addressed_line_node(from);
1226 	for (; bp != ep; bp = bp->q_forw) {
1227 		if ((s = get_sbuf_line(bp)) == NULL)
1228 			return ERR;
1229 		if (put_tty_line(s, bp->len, current_addr = from++, gflag) < 0)
1230 			return ERR;
1231 	}
1232 	return 0;
1233 }
1234 
1235 
1236 #define MAXMARK 26			/* max number of marks */
1237 
1238 static line_t *mark[MAXMARK];		/* line markers */
1239 static int markno;			/* line marker count */
1240 
1241 /* mark_line_node: set a line node mark */
1242 int
1243 mark_line_node(line_t *lp, int n)
1244 {
1245 	if (!islower((unsigned char)n)) {
1246 		errmsg = "invalid mark character";
1247 		return ERR;
1248 	} else if (mark[n - 'a'] == NULL)
1249 		markno++;
1250 	mark[n - 'a'] = lp;
1251 	return 0;
1252 }
1253 
1254 
1255 /* get_marked_node_addr: return address of a marked line */
1256 long
1257 get_marked_node_addr(int n)
1258 {
1259 	if (!islower((unsigned char)n)) {
1260 		errmsg = "invalid mark character";
1261 		return ERR;
1262 	}
1263 	return get_line_node_addr(mark[n - 'a']);
1264 }
1265 
1266 
1267 /* unmark_line_node: clear line node mark */
1268 void
1269 unmark_line_node(line_t *lp)
1270 {
1271 	int i;
1272 
1273 	for (i = 0; markno && i < MAXMARK; i++)
1274 		if (mark[i] == lp) {
1275 			mark[i] = NULL;
1276 			markno--;
1277 		}
1278 }
1279 
1280 
1281 /* dup_line_node: return a pointer to a copy of a line node */
1282 line_t *
1283 dup_line_node(line_t *lp)
1284 {
1285 	line_t *np;
1286 
1287 	if ((np = (line_t *) malloc(sizeof(line_t))) == NULL) {
1288 		fprintf(stderr, "%s\n", strerror(errno));
1289 		errmsg = "out of memory";
1290 		return NULL;
1291 	}
1292 	np->seek = lp->seek;
1293 	np->len = lp->len;
1294 	return np;
1295 }
1296 
1297 
1298 /* has_trailing_escape:  return the parity of escapes preceding a character
1299    in a string */
1300 int
1301 has_trailing_escape(char *s, char *t)
1302 {
1303     return (s == t || *(t - 1) != '\\') ? 0 : !has_trailing_escape(s, t - 1);
1304 }
1305 
1306 
1307 /* strip_escapes: return copy of escaped string of at most length PATH_MAX */
1308 char *
1309 strip_escapes(char *s)
1310 {
1311 	static char *file = NULL;
1312 	static int filesz = 0;
1313 
1314 	int i = 0;
1315 
1316 	REALLOC(file, filesz, PATH_MAX, NULL);
1317 	while (i < filesz - 1	/* Worry about a possible trailing escape */
1318 	       && (file[i++] = (*s == '\\') ? *++s : *s))
1319 		s++;
1320 	return file;
1321 }
1322 
1323 
1324 void
1325 signal_hup(int signo)
1326 {
1327 	if (mutex)
1328 		sigflags |= (1 << (signo - 1));
1329 	else
1330 		handle_hup(signo);
1331 }
1332 
1333 
1334 void
1335 signal_int(int signo)
1336 {
1337 	if (mutex)
1338 		sigflags |= (1 << (signo - 1));
1339 	else
1340 		handle_int(signo);
1341 }
1342 
1343 
1344 void
1345 handle_hup(int signo)
1346 {
1347 	char *hup = NULL;		/* hup filename */
1348 	char *s;
1349 	char ed_hup[] = "ed.hup";
1350 	int n;
1351 
1352 	if (!sigactive)
1353 		quit(1);
1354 	sigflags &= ~(1 << (signo - 1));
1355 	if (addr_last && write_file(ed_hup, "w", 1, addr_last) < 0 &&
1356 	    (s = getenv("HOME")) != NULL &&
1357 	    (n = strlen(s)) + 8 <= PATH_MAX &&	/* "ed.hup" + '/' */
1358 	    (hup = (char *) malloc(n + 10)) != NULL) {
1359 		strcpy(hup, s);
1360 		if (hup[n - 1] != '/')
1361 			hup[n] = '/', hup[n+1] = '\0';
1362 		strcat(hup, "ed.hup");
1363 		write_file(hup, "w", 1, addr_last);
1364 	}
1365 	quit(2);
1366 }
1367 
1368 
1369 void
1370 handle_int(int signo)
1371 {
1372 	if (!sigactive)
1373 		quit(1);
1374 	sigflags &= ~(1 << (signo - 1));
1375 #ifdef _POSIX_SOURCE
1376 	siglongjmp(env, -1);
1377 #else
1378 	longjmp(env, -1);
1379 #endif
1380 }
1381 
1382 
1383 int cols = 72;				/* wrap column */
1384 
1385 void
1386 handle_winch(int signo)
1387 {
1388 	int save_errno = errno;
1389 
1390 	struct winsize ws;		/* window size structure */
1391 
1392 	sigflags &= ~(1 << (signo - 1));
1393 	if (ioctl(0, TIOCGWINSZ, (char *) &ws) >= 0) {
1394 		if (ws.ws_row > 2) rows = ws.ws_row - 2;
1395 		if (ws.ws_col > 8) cols = ws.ws_col - 8;
1396 	}
1397 	errno = save_errno;
1398 }
1399 
1400 
1401 /* is_legal_filename: return a legal filename */
1402 int
1403 is_legal_filename(char *s)
1404 {
1405 	if (red && (*s == '!' || !strcmp(s, "..") || strchr(s, '/'))) {
1406 		errmsg = "shell access restricted";
1407 		return 0;
1408 	}
1409 	return 1;
1410 }
1411