xref: /freebsd/bin/ed/main.c (revision 9a14aa017b21c292740c00ee098195cd46642730)
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] [file]\n";
103 
104 /* ed: line editor */
105 int
106 main(volatile int argc, char ** volatile argv)
107 {
108 	int c, n;
109 	long status = 0;
110 
111 	(void)setlocale(LC_ALL, "");
112 
113 	red = (n = strlen(argv[0])) > 2 && argv[0][n - 3] == 'r';
114 top:
115 	while ((c = getopt(argc, argv, "p:sx")) != -1)
116 		switch(c) {
117 		case 'p':				/* set prompt */
118 			prompt = optarg;
119 			break;
120 		case 's':				/* run script */
121 			scripted = 1;
122 			break;
123 		case 'x':				/* use crypt */
124 #ifdef DES
125 			des = get_keyword();
126 #else
127 			fprintf(stderr, "crypt unavailable\n?\n");
128 #endif
129 			break;
130 
131 		default:
132 			fprintf(stderr, usage, red ? "red" : "ed");
133 			exit(1);
134 		}
135 	argv += optind;
136 	argc -= optind;
137 	if (argc && **argv == '-') {
138 		scripted = 1;
139 		if (argc > 1) {
140 			optind = 1;
141 			goto top;
142 		}
143 		argv++;
144 		argc--;
145 	}
146 	/* assert: reliable signals! */
147 #ifdef SIGWINCH
148 	handle_winch(SIGWINCH);
149 	if (isatty(0)) signal(SIGWINCH, handle_winch);
150 #endif
151 	signal(SIGHUP, signal_hup);
152 	signal(SIGQUIT, SIG_IGN);
153 	signal(SIGINT, signal_int);
154 #ifdef _POSIX_SOURCE
155 	if ((status = sigsetjmp(env, 1)))
156 #else
157 	if ((status = setjmp(env)))
158 #endif
159 	{
160 		fputs("\n?\n", stderr);
161 		errmsg = "interrupt";
162 	} else {
163 		init_buffers();
164 		sigactive = 1;			/* enable signal handlers */
165 		if (argc && **argv && is_legal_filename(*argv)) {
166 			if (read_file(*argv, 0) < 0 && !isatty(0))
167 				quit(2);
168 			else if (**argv != '!')
169 				if (strlcpy(old_filename, *argv, sizeof(old_filename))
170 				    >= sizeof(old_filename))
171 					quit(2);
172 		} else if (argc) {
173 			fputs("?\n", stderr);
174 			if (**argv == '\0')
175 				errmsg = "invalid filename";
176 			if (!isatty(0))
177 				quit(2);
178 		}
179 	}
180 	for (;;) {
181 		if (status < 0 && garrulous)
182 			fprintf(stderr, "%s\n", errmsg);
183 		if (prompt) {
184 			printf("%s", prompt);
185 			fflush(stdout);
186 		}
187 		if ((n = get_tty_line()) < 0) {
188 			status = ERR;
189 			continue;
190 		} else if (n == 0) {
191 			if (modified && !scripted) {
192 				fputs("?\n", stderr);
193 				errmsg = "warning: file modified";
194 				if (!isatty(0)) {
195 					if (garrulous)
196 						fprintf(stderr,
197 						    "script, line %d: %s\n",
198 						    lineno, errmsg);
199 					quit(2);
200 				}
201 				clearerr(stdin);
202 				modified = 0;
203 				status = EMOD;
204 				continue;
205 			} else
206 				quit(0);
207 		} else if (ibuf[n - 1] != '\n') {
208 			/* discard line */
209 			errmsg = "unexpected end-of-file";
210 			clearerr(stdin);
211 			status = ERR;
212 			continue;
213 		}
214 		isglobal = 0;
215 		if ((status = extract_addr_range()) >= 0 &&
216 		    (status = exec_command()) >= 0)
217 			if (!status ||
218 			    (status = display_lines(current_addr, current_addr,
219 			        status)) >= 0)
220 				continue;
221 		switch (status) {
222 		case EOF:
223 			quit(0);
224 		case EMOD:
225 			modified = 0;
226 			fputs("?\n", stderr);		/* give warning */
227 			errmsg = "warning: file modified";
228 			if (!isatty(0)) {
229 				if (garrulous)
230 					fprintf(stderr, "script, line %d: %s\n",
231 					    lineno, errmsg);
232 				quit(2);
233 			}
234 			break;
235 		case FATAL:
236 			if (!isatty(0)) {
237 				if (garrulous)
238 					fprintf(stderr, "script, line %d: %s\n",
239 					    lineno, errmsg);
240 			} else if (garrulous)
241 				fprintf(stderr, "%s\n", errmsg);
242 			quit(3);
243 		default:
244 			fputs("?\n", stderr);
245 			if (!isatty(0)) {
246 				if (garrulous)
247 					fprintf(stderr, "script, line %d: %s\n",
248 					    lineno, errmsg);
249 				quit(2);
250 			}
251 			break;
252 		}
253 	}
254 	/*NOTREACHED*/
255 }
256 
257 long first_addr, second_addr, addr_cnt;
258 
259 /* extract_addr_range: get line addresses from the command buffer until an
260    illegal address is seen; return status */
261 int
262 extract_addr_range(void)
263 {
264 	long addr;
265 
266 	addr_cnt = 0;
267 	first_addr = second_addr = current_addr;
268 	while ((addr = next_addr()) >= 0) {
269 		addr_cnt++;
270 		first_addr = second_addr;
271 		second_addr = addr;
272 		if (*ibufp != ',' && *ibufp != ';')
273 			break;
274 		else if (*ibufp++ == ';')
275 			current_addr = addr;
276 	}
277 	if ((addr_cnt = min(addr_cnt, 2)) == 1 || second_addr != addr)
278 		first_addr = second_addr;
279 	return (addr == ERR) ? ERR : 0;
280 }
281 
282 
283 #define SKIP_BLANKS() while (isspace((unsigned char)*ibufp) && *ibufp != '\n') ibufp++
284 
285 #define MUST_BE_FIRST() do {					\
286 	if (!first) {						\
287 		errmsg = "invalid address";			\
288 		return ERR;					\
289 	}							\
290 } while (0)
291 
292 /*  next_addr: return the next line address in the command buffer */
293 long
294 next_addr(void)
295 {
296 	const char *hd;
297 	long addr = current_addr;
298 	long n;
299 	int first = 1;
300 	int c;
301 
302 	SKIP_BLANKS();
303 	for (hd = ibufp;; first = 0)
304 		switch (c = *ibufp) {
305 		case '+':
306 		case '\t':
307 		case ' ':
308 		case '-':
309 		case '^':
310 			ibufp++;
311 			SKIP_BLANKS();
312 			if (isdigit((unsigned char)*ibufp)) {
313 				STRTOL(n, ibufp);
314 				addr += (c == '-' || c == '^') ? -n : n;
315 			} else if (!isspace((unsigned char)c))
316 				addr += (c == '-' || c == '^') ? -1 : 1;
317 			break;
318 		case '0': case '1': case '2':
319 		case '3': case '4': case '5':
320 		case '6': case '7': case '8': case '9':
321 			MUST_BE_FIRST();
322 			STRTOL(addr, ibufp);
323 			break;
324 		case '.':
325 		case '$':
326 			MUST_BE_FIRST();
327 			ibufp++;
328 			addr = (c == '.') ? current_addr : addr_last;
329 			break;
330 		case '/':
331 		case '?':
332 			MUST_BE_FIRST();
333 			if ((addr = get_matching_node_addr(
334 			    get_compiled_pattern(), c == '/')) < 0)
335 				return ERR;
336 			else if (c == *ibufp)
337 				ibufp++;
338 			break;
339 		case '\'':
340 			MUST_BE_FIRST();
341 			ibufp++;
342 			if ((addr = get_marked_node_addr(*ibufp++)) < 0)
343 				return ERR;
344 			break;
345 		case '%':
346 		case ',':
347 		case ';':
348 			if (first) {
349 				ibufp++;
350 				addr_cnt++;
351 				second_addr = (c == ';') ? current_addr : 1;
352 				addr = addr_last;
353 				break;
354 			}
355 			/* FALLTHROUGH */
356 		default:
357 			if (ibufp == hd)
358 				return EOF;
359 			else if (addr < 0 || addr_last < addr) {
360 				errmsg = "invalid address";
361 				return ERR;
362 			} else
363 				return addr;
364 		}
365 	/* NOTREACHED */
366 }
367 
368 
369 #ifdef BACKWARDS
370 /* GET_THIRD_ADDR: get a legal address from the command buffer */
371 #define GET_THIRD_ADDR(addr) \
372 { \
373 	long ol1, ol2; \
374 \
375 	ol1 = first_addr, ol2 = second_addr; \
376 	if (extract_addr_range() < 0) \
377 		return ERR; \
378 	else if (addr_cnt == 0) { \
379 		errmsg = "destination expected"; \
380 		return ERR; \
381 	} else if (second_addr < 0 || addr_last < second_addr) { \
382 		errmsg = "invalid address"; \
383 		return ERR; \
384 	} \
385 	addr = second_addr; \
386 	first_addr = ol1, second_addr = ol2; \
387 }
388 #else	/* BACKWARDS */
389 /* GET_THIRD_ADDR: get a legal address from the command buffer */
390 #define GET_THIRD_ADDR(addr) \
391 { \
392 	long ol1, ol2; \
393 \
394 	ol1 = first_addr, ol2 = second_addr; \
395 	if (extract_addr_range() < 0) \
396 		return ERR; \
397 	if (second_addr < 0 || addr_last < second_addr) { \
398 		errmsg = "invalid address"; \
399 		return ERR; \
400 	} \
401 	addr = second_addr; \
402 	first_addr = ol1, second_addr = ol2; \
403 }
404 #endif
405 
406 
407 /* GET_COMMAND_SUFFIX: verify the command suffix in the command buffer */
408 #define GET_COMMAND_SUFFIX() { \
409 	int done = 0; \
410 	do { \
411 		switch(*ibufp) { \
412 		case 'p': \
413 			gflag |= GPR, ibufp++; \
414 			break; \
415 		case 'l': \
416 			gflag |= GLS, ibufp++; \
417 			break; \
418 		case 'n': \
419 			gflag |= GNP, ibufp++; \
420 			break; \
421 		default: \
422 			done++; \
423 		} \
424 	} while (!done); \
425 	if (*ibufp++ != '\n') { \
426 		errmsg = "invalid command suffix"; \
427 		return ERR; \
428 	} \
429 }
430 
431 
432 /* sflags */
433 #define SGG 001		/* complement previous global substitute suffix */
434 #define SGP 002		/* complement previous print suffix */
435 #define SGR 004		/* use last regex instead of last pat */
436 #define SGF 010		/* repeat last substitution */
437 
438 int patlock = 0;	/* if set, pattern not freed by get_compiled_pattern() */
439 
440 long rows = 22;		/* scroll length: ws_row - 2 */
441 
442 /* exec_command: execute the next command in command buffer; return print
443    request, if any */
444 int
445 exec_command(void)
446 {
447 	static pattern_t *pat = NULL;
448 	static int sgflag = 0;
449 	static long sgnum = 0;
450 
451 	pattern_t *tpat;
452 	char *fnp;
453 	int gflag = 0;
454 	int sflags = 0;
455 	long addr = 0;
456 	int n = 0;
457 	int c;
458 
459 	SKIP_BLANKS();
460 	switch(c = *ibufp++) {
461 	case 'a':
462 		GET_COMMAND_SUFFIX();
463 		if (!isglobal) clear_undo_stack();
464 		if (append_lines(second_addr) < 0)
465 			return ERR;
466 		break;
467 	case 'c':
468 		if (check_addr_range(current_addr, current_addr) < 0)
469 			return ERR;
470 		GET_COMMAND_SUFFIX();
471 		if (!isglobal) clear_undo_stack();
472 		if (delete_lines(first_addr, second_addr) < 0 ||
473 		    append_lines(current_addr) < 0)
474 			return ERR;
475 		break;
476 	case 'd':
477 		if (check_addr_range(current_addr, current_addr) < 0)
478 			return ERR;
479 		GET_COMMAND_SUFFIX();
480 		if (!isglobal) clear_undo_stack();
481 		if (delete_lines(first_addr, second_addr) < 0)
482 			return ERR;
483 		else if ((addr = INC_MOD(current_addr, addr_last)) != 0)
484 			current_addr = addr;
485 		break;
486 	case 'e':
487 		if (modified && !scripted)
488 			return EMOD;
489 		/* FALLTHROUGH */
490 	case 'E':
491 		if (addr_cnt > 0) {
492 			errmsg = "unexpected address";
493 			return ERR;
494 		} else if (!isspace((unsigned char)*ibufp)) {
495 			errmsg = "unexpected command suffix";
496 			return ERR;
497 		} else if ((fnp = get_filename()) == NULL)
498 			return ERR;
499 		GET_COMMAND_SUFFIX();
500 		if (delete_lines(1, addr_last) < 0)
501 			return ERR;
502 		clear_undo_stack();
503 		if (close_sbuf() < 0)
504 			return ERR;
505 		else if (open_sbuf() < 0)
506 			return FATAL;
507 		if (*fnp && *fnp != '!') strcpy(old_filename, fnp);
508 #ifdef BACKWARDS
509 		if (*fnp == '\0' && *old_filename == '\0') {
510 			errmsg = "no current filename";
511 			return ERR;
512 		}
513 #endif
514 		if (read_file(*fnp ? fnp : old_filename, 0) < 0)
515 			return ERR;
516 		clear_undo_stack();
517 		modified = 0;
518 		u_current_addr = u_addr_last = -1;
519 		break;
520 	case 'f':
521 		if (addr_cnt > 0) {
522 			errmsg = "unexpected address";
523 			return ERR;
524 		} else if (!isspace((unsigned char)*ibufp)) {
525 			errmsg = "unexpected command suffix";
526 			return ERR;
527 		} else if ((fnp = get_filename()) == NULL)
528 			return ERR;
529 		else if (*fnp == '!') {
530 			errmsg = "invalid redirection";
531 			return ERR;
532 		}
533 		GET_COMMAND_SUFFIX();
534 		if (*fnp) strcpy(old_filename, fnp);
535 		printf("%s\n", strip_escapes(old_filename));
536 		break;
537 	case 'g':
538 	case 'v':
539 	case 'G':
540 	case 'V':
541 		if (isglobal) {
542 			errmsg = "cannot nest global commands";
543 			return ERR;
544 		} else if (check_addr_range(1, addr_last) < 0)
545 			return ERR;
546 		else if (build_active_list(c == 'g' || c == 'G') < 0)
547 			return ERR;
548 		else if ((n = (c == 'G' || c == 'V')))
549 			GET_COMMAND_SUFFIX();
550 		isglobal++;
551 		if (exec_global(n, gflag) < 0)
552 			return ERR;
553 		break;
554 	case 'h':
555 		if (addr_cnt > 0) {
556 			errmsg = "unexpected address";
557 			return ERR;
558 		}
559 		GET_COMMAND_SUFFIX();
560 		if (*errmsg) fprintf(stderr, "%s\n", errmsg);
561 		break;
562 	case 'H':
563 		if (addr_cnt > 0) {
564 			errmsg = "unexpected address";
565 			return ERR;
566 		}
567 		GET_COMMAND_SUFFIX();
568 		if ((garrulous = 1 - garrulous) && *errmsg)
569 			fprintf(stderr, "%s\n", errmsg);
570 		break;
571 	case 'i':
572 		if (second_addr == 0) {
573 			errmsg = "invalid address";
574 			return ERR;
575 		}
576 		GET_COMMAND_SUFFIX();
577 		if (!isglobal) clear_undo_stack();
578 		if (append_lines(second_addr - 1) < 0)
579 			return ERR;
580 		break;
581 	case 'j':
582 		if (check_addr_range(current_addr, current_addr + 1) < 0)
583 			return ERR;
584 		GET_COMMAND_SUFFIX();
585 		if (!isglobal) clear_undo_stack();
586 		if (first_addr != second_addr &&
587 		    join_lines(first_addr, second_addr) < 0)
588 			return ERR;
589 		break;
590 	case 'k':
591 		c = *ibufp++;
592 		if (second_addr == 0) {
593 			errmsg = "invalid address";
594 			return ERR;
595 		}
596 		GET_COMMAND_SUFFIX();
597 		if (mark_line_node(get_addressed_line_node(second_addr), c) < 0)
598 			return ERR;
599 		break;
600 	case 'l':
601 		if (check_addr_range(current_addr, current_addr) < 0)
602 			return ERR;
603 		GET_COMMAND_SUFFIX();
604 		if (display_lines(first_addr, second_addr, gflag | GLS) < 0)
605 			return ERR;
606 		gflag = 0;
607 		break;
608 	case 'm':
609 		if (check_addr_range(current_addr, current_addr) < 0)
610 			return ERR;
611 		GET_THIRD_ADDR(addr);
612 		if (first_addr <= addr && addr < second_addr) {
613 			errmsg = "invalid destination";
614 			return ERR;
615 		}
616 		GET_COMMAND_SUFFIX();
617 		if (!isglobal) clear_undo_stack();
618 		if (move_lines(addr) < 0)
619 			return ERR;
620 		break;
621 	case 'n':
622 		if (check_addr_range(current_addr, current_addr) < 0)
623 			return ERR;
624 		GET_COMMAND_SUFFIX();
625 		if (display_lines(first_addr, second_addr, gflag | GNP) < 0)
626 			return ERR;
627 		gflag = 0;
628 		break;
629 	case 'p':
630 		if (check_addr_range(current_addr, current_addr) < 0)
631 			return ERR;
632 		GET_COMMAND_SUFFIX();
633 		if (display_lines(first_addr, second_addr, gflag | GPR) < 0)
634 			return ERR;
635 		gflag = 0;
636 		break;
637 	case 'P':
638 		if (addr_cnt > 0) {
639 			errmsg = "unexpected address";
640 			return ERR;
641 		}
642 		GET_COMMAND_SUFFIX();
643 		prompt = prompt ? NULL : optarg ? optarg : dps;
644 		break;
645 	case 'q':
646 	case 'Q':
647 		if (addr_cnt > 0) {
648 			errmsg = "unexpected address";
649 			return ERR;
650 		}
651 		GET_COMMAND_SUFFIX();
652 		gflag =  (modified && !scripted && c == 'q') ? EMOD : EOF;
653 		break;
654 	case 'r':
655 		if (!isspace((unsigned char)*ibufp)) {
656 			errmsg = "unexpected command suffix";
657 			return ERR;
658 		} else if (addr_cnt == 0)
659 			second_addr = addr_last;
660 		if ((fnp = get_filename()) == NULL)
661 			return ERR;
662 		GET_COMMAND_SUFFIX();
663 		if (!isglobal) clear_undo_stack();
664 		if (*old_filename == '\0' && *fnp != '!')
665 			strcpy(old_filename, fnp);
666 #ifdef BACKWARDS
667 		if (*fnp == '\0' && *old_filename == '\0') {
668 			errmsg = "no current filename";
669 			return ERR;
670 		}
671 #endif
672 		if ((addr = read_file(*fnp ? fnp : old_filename, second_addr)) < 0)
673 			return ERR;
674 		else if (addr && addr != addr_last)
675 			modified = 1;
676 		break;
677 	case 's':
678 		do {
679 			switch(*ibufp) {
680 			case '\n':
681 				sflags |=SGF;
682 				break;
683 			case 'g':
684 				sflags |= SGG;
685 				ibufp++;
686 				break;
687 			case 'p':
688 				sflags |= SGP;
689 				ibufp++;
690 				break;
691 			case 'r':
692 				sflags |= SGR;
693 				ibufp++;
694 				break;
695 			case '0': case '1': case '2': case '3': case '4':
696 			case '5': case '6': case '7': case '8': case '9':
697 				STRTOL(sgnum, ibufp);
698 				sflags |= SGF;
699 				sgflag &= ~GSG;		/* override GSG */
700 				break;
701 			default:
702 				if (sflags) {
703 					errmsg = "invalid command suffix";
704 					return ERR;
705 				}
706 			}
707 		} while (sflags && *ibufp != '\n');
708 		if (sflags && !pat) {
709 			errmsg = "no previous substitution";
710 			return ERR;
711 		} else if (sflags & SGG)
712 			sgnum = 0;		/* override numeric arg */
713 		if (*ibufp != '\n' && *(ibufp + 1) == '\n') {
714 			errmsg = "invalid pattern delimiter";
715 			return ERR;
716 		}
717 		tpat = pat;
718 		SPL1();
719 		if ((!sflags || (sflags & SGR)) &&
720 		    (tpat = get_compiled_pattern()) == NULL) {
721 		 	SPL0();
722 			return ERR;
723 		} else if (tpat != pat) {
724 			if (pat) {
725 				regfree(pat);
726 				free(pat);
727 			}
728 			pat = tpat;
729 			patlock = 1;		/* reserve pattern */
730 		}
731 		SPL0();
732 		if (!sflags && extract_subst_tail(&sgflag, &sgnum) < 0)
733 			return ERR;
734 		else if (isglobal)
735 			sgflag |= GLB;
736 		else
737 			sgflag &= ~GLB;
738 		if (sflags & SGG)
739 			sgflag ^= GSG;
740 		if (sflags & SGP)
741 			sgflag ^= GPR, sgflag &= ~(GLS | GNP);
742 		do {
743 			switch(*ibufp) {
744 			case 'p':
745 				sgflag |= GPR, ibufp++;
746 				break;
747 			case 'l':
748 				sgflag |= GLS, ibufp++;
749 				break;
750 			case 'n':
751 				sgflag |= GNP, ibufp++;
752 				break;
753 			default:
754 				n++;
755 			}
756 		} while (!n);
757 		if (check_addr_range(current_addr, current_addr) < 0)
758 			return ERR;
759 		GET_COMMAND_SUFFIX();
760 		if (!isglobal) clear_undo_stack();
761 		if (search_and_replace(pat, sgflag, sgnum) < 0)
762 			return ERR;
763 		break;
764 	case 't':
765 		if (check_addr_range(current_addr, current_addr) < 0)
766 			return ERR;
767 		GET_THIRD_ADDR(addr);
768 		GET_COMMAND_SUFFIX();
769 		if (!isglobal) clear_undo_stack();
770 		if (copy_lines(addr) < 0)
771 			return ERR;
772 		break;
773 	case 'u':
774 		if (addr_cnt > 0) {
775 			errmsg = "unexpected address";
776 			return ERR;
777 		}
778 		GET_COMMAND_SUFFIX();
779 		if (pop_undo_stack() < 0)
780 			return ERR;
781 		break;
782 	case 'w':
783 	case 'W':
784 		if ((n = *ibufp) == 'q' || n == 'Q') {
785 			gflag = EOF;
786 			ibufp++;
787 		}
788 		if (!isspace((unsigned char)*ibufp)) {
789 			errmsg = "unexpected command suffix";
790 			return ERR;
791 		} else if ((fnp = get_filename()) == NULL)
792 			return ERR;
793 		if (addr_cnt == 0 && !addr_last)
794 			first_addr = second_addr = 0;
795 		else if (check_addr_range(1, addr_last) < 0)
796 			return ERR;
797 		GET_COMMAND_SUFFIX();
798 		if (*old_filename == '\0' && *fnp != '!')
799 			strcpy(old_filename, fnp);
800 #ifdef BACKWARDS
801 		if (*fnp == '\0' && *old_filename == '\0') {
802 			errmsg = "no current filename";
803 			return ERR;
804 		}
805 #endif
806 		if ((addr = write_file(*fnp ? fnp : old_filename,
807 		    (c == 'W') ? "a" : "w", first_addr, second_addr)) < 0)
808 			return ERR;
809 		else if (addr == addr_last)
810 			modified = 0;
811 		else if (modified && !scripted && n == 'q')
812 			gflag = EMOD;
813 		break;
814 	case 'x':
815 		if (addr_cnt > 0) {
816 			errmsg = "unexpected address";
817 			return ERR;
818 		}
819 		GET_COMMAND_SUFFIX();
820 #ifdef DES
821 		des = get_keyword();
822 		break;
823 #else
824 		errmsg = "crypt unavailable";
825 		return ERR;
826 #endif
827 	case 'z':
828 #ifdef BACKWARDS
829 		if (check_addr_range(first_addr = 1, current_addr + 1) < 0)
830 #else
831 		if (check_addr_range(first_addr = 1, current_addr + !isglobal) < 0)
832 #endif
833 			return ERR;
834 		else if ('0' < *ibufp && *ibufp <= '9')
835 			STRTOL(rows, ibufp);
836 		GET_COMMAND_SUFFIX();
837 		if (display_lines(second_addr, min(addr_last,
838 		    second_addr + rows), gflag) < 0)
839 			return ERR;
840 		gflag = 0;
841 		break;
842 	case '=':
843 		GET_COMMAND_SUFFIX();
844 		printf("%ld\n", addr_cnt ? second_addr : addr_last);
845 		break;
846 	case '!':
847 		if (addr_cnt > 0) {
848 			errmsg = "unexpected address";
849 			return ERR;
850 		} else if ((sflags = get_shell_command()) < 0)
851 			return ERR;
852 		GET_COMMAND_SUFFIX();
853 		if (sflags) printf("%s\n", shcmd + 1);
854 		system(shcmd + 1);
855 		if (!scripted) printf("!\n");
856 		break;
857 	case '\n':
858 #ifdef BACKWARDS
859 		if (check_addr_range(first_addr = 1, current_addr + 1) < 0
860 #else
861 		if (check_addr_range(first_addr = 1, current_addr + !isglobal) < 0
862 #endif
863 		 || display_lines(second_addr, second_addr, 0) < 0)
864 			return ERR;
865 		break;
866 	default:
867 		errmsg = "unknown command";
868 		return ERR;
869 	}
870 	return gflag;
871 }
872 
873 
874 /* check_addr_range: return status of address range check */
875 int
876 check_addr_range(long n, long m)
877 {
878 	if (addr_cnt == 0) {
879 		first_addr = n;
880 		second_addr = m;
881 	}
882 	if (first_addr > second_addr || 1 > first_addr ||
883 	    second_addr > addr_last) {
884 		errmsg = "invalid address";
885 		return ERR;
886 	}
887 	return 0;
888 }
889 
890 
891 /* get_matching_node_addr: return the address of the next line matching a
892    pattern in a given direction.  wrap around begin/end of editor buffer if
893    necessary */
894 long
895 get_matching_node_addr(pattern_t *pat, int dir)
896 {
897 	char *s;
898 	long n = current_addr;
899 	line_t *lp;
900 
901 	if (!pat) return ERR;
902 	do {
903 	       if ((n = dir ? INC_MOD(n, addr_last) : DEC_MOD(n, addr_last))) {
904 			lp = get_addressed_line_node(n);
905 			if ((s = get_sbuf_line(lp)) == NULL)
906 				return ERR;
907 			if (isbinary)
908 				NUL_TO_NEWLINE(s, lp->len);
909 			if (!regexec(pat, s, 0, NULL, 0))
910 				return n;
911 	       }
912 	} while (n != current_addr);
913 	errmsg = "no match";
914 	return  ERR;
915 }
916 
917 
918 /* get_filename: return pointer to copy of filename in the command buffer */
919 char *
920 get_filename(void)
921 {
922 	static char *file = NULL;
923 	static int filesz = 0;
924 
925 	int n;
926 
927 	if (*ibufp != '\n') {
928 		SKIP_BLANKS();
929 		if (*ibufp == '\n') {
930 			errmsg = "invalid filename";
931 			return NULL;
932 		} else if ((ibufp = get_extended_line(&n, 1)) == NULL)
933 			return NULL;
934 		else if (*ibufp == '!') {
935 			ibufp++;
936 			if ((n = get_shell_command()) < 0)
937 				return NULL;
938 			if (n)
939 				printf("%s\n", shcmd + 1);
940 			return shcmd;
941 		} else if (n > PATH_MAX - 1) {
942 			errmsg = "filename too long";
943 			return  NULL;
944 		}
945 	}
946 #ifndef BACKWARDS
947 	else if (*old_filename == '\0') {
948 		errmsg = "no current filename";
949 		return  NULL;
950 	}
951 #endif
952 	REALLOC(file, filesz, PATH_MAX, NULL);
953 	for (n = 0; *ibufp != '\n';)
954 		file[n++] = *ibufp++;
955 	file[n] = '\0';
956 	return is_legal_filename(file) ? file : NULL;
957 }
958 
959 
960 /* get_shell_command: read a shell command from stdin; return substitution
961    status */
962 int
963 get_shell_command(void)
964 {
965 	static char *buf = NULL;
966 	static int n = 0;
967 
968 	char *s;			/* substitution char pointer */
969 	int i = 0;
970 	int j = 0;
971 
972 	if (red) {
973 		errmsg = "shell access restricted";
974 		return ERR;
975 	} else if ((s = ibufp = get_extended_line(&j, 1)) == NULL)
976 		return ERR;
977 	REALLOC(buf, n, j + 1, ERR);
978 	buf[i++] = '!';			/* prefix command w/ bang */
979 	while (*ibufp != '\n')
980 		switch (*ibufp) {
981 		default:
982 			REALLOC(buf, n, i + 2, ERR);
983 			buf[i++] = *ibufp;
984 			if (*ibufp++ == '\\')
985 				buf[i++] = *ibufp++;
986 			break;
987 		case '!':
988 			if (s != ibufp) {
989 				REALLOC(buf, n, i + 1, ERR);
990 				buf[i++] = *ibufp++;
991 			}
992 #ifdef BACKWARDS
993 			else if (shcmd == NULL || *(shcmd + 1) == '\0')
994 #else
995 			else if (shcmd == NULL)
996 #endif
997 			{
998 				errmsg = "no previous command";
999 				return ERR;
1000 			} else {
1001 				REALLOC(buf, n, i + shcmdi, ERR);
1002 				for (s = shcmd + 1; s < shcmd + shcmdi;)
1003 					buf[i++] = *s++;
1004 				s = ibufp++;
1005 			}
1006 			break;
1007 		case '%':
1008 			if (*old_filename  == '\0') {
1009 				errmsg = "no current filename";
1010 				return ERR;
1011 			}
1012 			j = strlen(s = strip_escapes(old_filename));
1013 			REALLOC(buf, n, i + j, ERR);
1014 			while (j--)
1015 				buf[i++] = *s++;
1016 			s = ibufp++;
1017 			break;
1018 		}
1019 	REALLOC(shcmd, shcmdsz, i + 1, ERR);
1020 	memcpy(shcmd, buf, i);
1021 	shcmd[shcmdi = i] = '\0';
1022 	return *s == '!' || *s == '%';
1023 }
1024 
1025 
1026 /* append_lines: insert text from stdin to after line n; stop when either a
1027    single period is read or EOF; return status */
1028 int
1029 append_lines(long n)
1030 {
1031 	int l;
1032 	const char *lp = ibuf;
1033 	const char *eot;
1034 	undo_t *up = NULL;
1035 
1036 	for (current_addr = n;;) {
1037 		if (!isglobal) {
1038 			if ((l = get_tty_line()) < 0)
1039 				return ERR;
1040 			else if (l == 0 || ibuf[l - 1] != '\n') {
1041 				clearerr(stdin);
1042 				return  l ? EOF : 0;
1043 			}
1044 			lp = ibuf;
1045 		} else if (*(lp = ibufp) == '\0')
1046 			return 0;
1047 		else {
1048 			while (*ibufp++ != '\n')
1049 				;
1050 			l = ibufp - lp;
1051 		}
1052 		if (l == 2 && lp[0] == '.' && lp[1] == '\n') {
1053 			return 0;
1054 		}
1055 		eot = lp + l;
1056 		SPL1();
1057 		do {
1058 			if ((lp = put_sbuf_line(lp)) == NULL) {
1059 				SPL0();
1060 				return ERR;
1061 			} else if (up)
1062 				up->t = get_addressed_line_node(current_addr);
1063 			else if ((up = push_undo_stack(UADD, current_addr,
1064 			    current_addr)) == NULL) {
1065 				SPL0();
1066 				return ERR;
1067 			}
1068 		} while (lp != eot);
1069 		modified = 1;
1070 		SPL0();
1071 	}
1072 	/* NOTREACHED */
1073 }
1074 
1075 
1076 /* join_lines: replace a range of lines with the joined text of those lines */
1077 int
1078 join_lines(long from, long to)
1079 {
1080 	static char *buf = NULL;
1081 	static int n;
1082 
1083 	char *s;
1084 	int size = 0;
1085 	line_t *bp, *ep;
1086 
1087 	ep = get_addressed_line_node(INC_MOD(to, addr_last));
1088 	bp = get_addressed_line_node(from);
1089 	for (; bp != ep; bp = bp->q_forw) {
1090 		if ((s = get_sbuf_line(bp)) == NULL)
1091 			return ERR;
1092 		REALLOC(buf, n, size + bp->len, ERR);
1093 		memcpy(buf + size, s, bp->len);
1094 		size += bp->len;
1095 	}
1096 	REALLOC(buf, n, size + 2, ERR);
1097 	memcpy(buf + size, "\n", 2);
1098 	if (delete_lines(from, to) < 0)
1099 		return ERR;
1100 	current_addr = from - 1;
1101 	SPL1();
1102 	if (put_sbuf_line(buf) == NULL ||
1103 	    push_undo_stack(UADD, current_addr, current_addr) == NULL) {
1104 		SPL0();
1105 		return ERR;
1106 	}
1107 	modified = 1;
1108 	SPL0();
1109 	return 0;
1110 }
1111 
1112 
1113 /* move_lines: move a range of lines */
1114 int
1115 move_lines(long addr)
1116 {
1117 	line_t *b1, *a1, *b2, *a2;
1118 	long n = INC_MOD(second_addr, addr_last);
1119 	long p = first_addr - 1;
1120 	int done = (addr == first_addr - 1 || addr == second_addr);
1121 
1122 	SPL1();
1123 	if (done) {
1124 		a2 = get_addressed_line_node(n);
1125 		b2 = get_addressed_line_node(p);
1126 		current_addr = second_addr;
1127 	} else if (push_undo_stack(UMOV, p, n) == NULL ||
1128 	    push_undo_stack(UMOV, addr, INC_MOD(addr, addr_last)) == NULL) {
1129 		SPL0();
1130 		return ERR;
1131 	} else {
1132 		a1 = get_addressed_line_node(n);
1133 		if (addr < first_addr) {
1134 			b1 = get_addressed_line_node(p);
1135 			b2 = get_addressed_line_node(addr);
1136 					/* this get_addressed_line_node last! */
1137 		} else {
1138 			b2 = get_addressed_line_node(addr);
1139 			b1 = get_addressed_line_node(p);
1140 					/* this get_addressed_line_node last! */
1141 		}
1142 		a2 = b2->q_forw;
1143 		REQUE(b2, b1->q_forw);
1144 		REQUE(a1->q_back, a2);
1145 		REQUE(b1, a1);
1146 		current_addr = addr + ((addr < first_addr) ?
1147 		    second_addr - first_addr + 1 : 0);
1148 	}
1149 	if (isglobal)
1150 		unset_active_nodes(b2->q_forw, a2);
1151 	modified = 1;
1152 	SPL0();
1153 	return 0;
1154 }
1155 
1156 
1157 /* copy_lines: copy a range of lines; return status */
1158 int
1159 copy_lines(long addr)
1160 {
1161 	line_t *lp, *np = get_addressed_line_node(first_addr);
1162 	undo_t *up = NULL;
1163 	long n = second_addr - first_addr + 1;
1164 	long m = 0;
1165 
1166 	current_addr = addr;
1167 	if (first_addr <= addr && addr < second_addr) {
1168 		n =  addr - first_addr + 1;
1169 		m = second_addr - addr;
1170 	}
1171 	for (; n > 0; n=m, m=0, np = get_addressed_line_node(current_addr + 1))
1172 		for (; n-- > 0; np = np->q_forw) {
1173 			SPL1();
1174 			if ((lp = dup_line_node(np)) == NULL) {
1175 				SPL0();
1176 				return ERR;
1177 			}
1178 			add_line_node(lp);
1179 			if (up)
1180 				up->t = lp;
1181 			else if ((up = push_undo_stack(UADD, current_addr,
1182 			    current_addr)) == NULL) {
1183 				SPL0();
1184 				return ERR;
1185 			}
1186 			modified = 1;
1187 			SPL0();
1188 		}
1189 	return 0;
1190 }
1191 
1192 
1193 /* delete_lines: delete a range of lines */
1194 int
1195 delete_lines(long from, long to)
1196 {
1197 	line_t *n, *p;
1198 
1199 	SPL1();
1200 	if (push_undo_stack(UDEL, from, to) == NULL) {
1201 		SPL0();
1202 		return ERR;
1203 	}
1204 	n = get_addressed_line_node(INC_MOD(to, addr_last));
1205 	p = get_addressed_line_node(from - 1);
1206 					/* this get_addressed_line_node last! */
1207 	if (isglobal)
1208 		unset_active_nodes(p->q_forw, n);
1209 	REQUE(p, n);
1210 	addr_last -= to - from + 1;
1211 	current_addr = from - 1;
1212 	modified = 1;
1213 	SPL0();
1214 	return 0;
1215 }
1216 
1217 
1218 /* display_lines: print a range of lines to stdout */
1219 int
1220 display_lines(long from, long to, int gflag)
1221 {
1222 	line_t *bp;
1223 	line_t *ep;
1224 	char *s;
1225 
1226 	if (!from) {
1227 		errmsg = "invalid address";
1228 		return ERR;
1229 	}
1230 	ep = get_addressed_line_node(INC_MOD(to, addr_last));
1231 	bp = get_addressed_line_node(from);
1232 	for (; bp != ep; bp = bp->q_forw) {
1233 		if ((s = get_sbuf_line(bp)) == NULL)
1234 			return ERR;
1235 		if (put_tty_line(s, bp->len, current_addr = from++, gflag) < 0)
1236 			return ERR;
1237 	}
1238 	return 0;
1239 }
1240 
1241 
1242 #define MAXMARK 26			/* max number of marks */
1243 
1244 line_t	*mark[MAXMARK];			/* line markers */
1245 int markno;				/* line marker count */
1246 
1247 /* mark_line_node: set a line node mark */
1248 int
1249 mark_line_node(line_t *lp, int n)
1250 {
1251 	if (!islower((unsigned char)n)) {
1252 		errmsg = "invalid mark character";
1253 		return ERR;
1254 	} else if (mark[n - 'a'] == NULL)
1255 		markno++;
1256 	mark[n - 'a'] = lp;
1257 	return 0;
1258 }
1259 
1260 
1261 /* get_marked_node_addr: return address of a marked line */
1262 long
1263 get_marked_node_addr(int n)
1264 {
1265 	if (!islower((unsigned char)n)) {
1266 		errmsg = "invalid mark character";
1267 		return ERR;
1268 	}
1269 	return get_line_node_addr(mark[n - 'a']);
1270 }
1271 
1272 
1273 /* unmark_line_node: clear line node mark */
1274 void
1275 unmark_line_node(line_t *lp)
1276 {
1277 	int i;
1278 
1279 	for (i = 0; markno && i < MAXMARK; i++)
1280 		if (mark[i] == lp) {
1281 			mark[i] = NULL;
1282 			markno--;
1283 		}
1284 }
1285 
1286 
1287 /* dup_line_node: return a pointer to a copy of a line node */
1288 line_t *
1289 dup_line_node(line_t *lp)
1290 {
1291 	line_t *np;
1292 
1293 	if ((np = (line_t *) malloc(sizeof(line_t))) == NULL) {
1294 		fprintf(stderr, "%s\n", strerror(errno));
1295 		errmsg = "out of memory";
1296 		return NULL;
1297 	}
1298 	np->seek = lp->seek;
1299 	np->len = lp->len;
1300 	return np;
1301 }
1302 
1303 
1304 /* has_trailing_escape:  return the parity of escapes preceding a character
1305    in a string */
1306 int
1307 has_trailing_escape(char *s, char *t)
1308 {
1309     return (s == t || *(t - 1) != '\\') ? 0 : !has_trailing_escape(s, t - 1);
1310 }
1311 
1312 
1313 /* strip_escapes: return copy of escaped string of at most length PATH_MAX */
1314 char *
1315 strip_escapes(char *s)
1316 {
1317 	static char *file = NULL;
1318 	static int filesz = 0;
1319 
1320 	int i = 0;
1321 
1322 	REALLOC(file, filesz, PATH_MAX, NULL);
1323 	while (i < filesz - 1	/* Worry about a possible trailing escape */
1324 	       && (file[i++] = (*s == '\\') ? *++s : *s))
1325 		s++;
1326 	return file;
1327 }
1328 
1329 
1330 void
1331 signal_hup(int signo)
1332 {
1333 	if (mutex)
1334 		sigflags |= (1 << (signo - 1));
1335 	else
1336 		handle_hup(signo);
1337 }
1338 
1339 
1340 void
1341 signal_int(int signo)
1342 {
1343 	if (mutex)
1344 		sigflags |= (1 << (signo - 1));
1345 	else
1346 		handle_int(signo);
1347 }
1348 
1349 
1350 void
1351 handle_hup(int signo)
1352 {
1353 	char *hup = NULL;		/* hup filename */
1354 	char *s;
1355 	char ed_hup[] = "ed.hup";
1356 	int n;
1357 
1358 	if (!sigactive)
1359 		quit(1);
1360 	sigflags &= ~(1 << (signo - 1));
1361 	if (addr_last && write_file(ed_hup, "w", 1, addr_last) < 0 &&
1362 	    (s = getenv("HOME")) != NULL &&
1363 	    (n = strlen(s)) + 8 <= PATH_MAX &&	/* "ed.hup" + '/' */
1364 	    (hup = (char *) malloc(n + 10)) != NULL) {
1365 		strcpy(hup, s);
1366 		if (hup[n - 1] != '/')
1367 			hup[n] = '/', hup[n+1] = '\0';
1368 		strcat(hup, "ed.hup");
1369 		write_file(hup, "w", 1, addr_last);
1370 	}
1371 	quit(2);
1372 }
1373 
1374 
1375 void
1376 handle_int(int signo)
1377 {
1378 	if (!sigactive)
1379 		quit(1);
1380 	sigflags &= ~(1 << (signo - 1));
1381 #ifdef _POSIX_SOURCE
1382 	siglongjmp(env, -1);
1383 #else
1384 	longjmp(env, -1);
1385 #endif
1386 }
1387 
1388 
1389 int cols = 72;				/* wrap column */
1390 
1391 void
1392 handle_winch(int signo)
1393 {
1394 	int save_errno = errno;
1395 
1396 	struct winsize ws;		/* window size structure */
1397 
1398 	sigflags &= ~(1 << (signo - 1));
1399 	if (ioctl(0, TIOCGWINSZ, (char *) &ws) >= 0) {
1400 		if (ws.ws_row > 2) rows = ws.ws_row - 2;
1401 		if (ws.ws_col > 8) cols = ws.ws_col - 8;
1402 	}
1403 	errno = save_errno;
1404 }
1405 
1406 
1407 /* is_legal_filename: return a legal filename */
1408 int
1409 is_legal_filename(char *s)
1410 {
1411 	if (red && (*s == '!' || !strcmp(s, "..") || strchr(s, '/'))) {
1412 		errmsg = "shell access restricted";
1413 		return 0;
1414 	}
1415 	return 1;
1416 }
1417