xref: /freebsd/bin/ed/main.c (revision 4c1a82cea504df7a79f5bd8f7d0a41cacccff16e)
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  */
51 
52 #include <sys/types.h>
53 
54 #include <sys/ioctl.h>
55 #include <sys/wait.h>
56 #include <ctype.h>
57 #include <locale.h>
58 #include <pwd.h>
59 #include <setjmp.h>
60 
61 #include "ed.h"
62 
63 
64 #ifdef _POSIX_SOURCE
65 static sigjmp_buf env;
66 #else
67 static jmp_buf env;
68 #endif
69 
70 /* static buffers */
71 char stdinbuf[1];		/* stdin buffer */
72 static char *shcmd;		/* shell command buffer */
73 static int shcmdsz;		/* shell command buffer size */
74 static int shcmdi;		/* shell command buffer index */
75 char *ibuf;			/* ed command-line buffer */
76 int ibufsz;			/* ed command-line buffer size */
77 char *ibufp;			/* pointer to ed command-line buffer */
78 
79 /* global flags */
80 static int garrulous = 0;	/* if set, print all error messages */
81 int isbinary;			/* if set, buffer contains ASCII NULs */
82 int isglobal;			/* if set, doing a global command */
83 int modified;			/* if set, buffer modified since last write */
84 int mutex = 0;			/* if set, signals set "sigflags" */
85 static int red = 0;		/* if set, restrict shell/directory access */
86 int scripted = 0;		/* if set, suppress diagnostics */
87 int sigflags = 0;		/* if set, signals received while mutex set */
88 static int sigactive = 0;	/* if set, signal handlers are enabled */
89 
90 static char old_filename[PATH_MAX] = ""; /* default filename */
91 long current_addr;		/* current address in editor buffer */
92 long addr_last;			/* last address in editor buffer */
93 int lineno;			/* script line number */
94 static const char *prompt;	/* command-line prompt */
95 static const char *dps = "*";	/* default command-line prompt */
96 
97 static const char *usage = "usage: %s [-] [-sx] [-p string] [file]\n";
98 
99 /* ed: line editor */
100 int
101 main(volatile int argc, char ** volatile argv)
102 {
103 	int c, n;
104 	long status = 0;
105 
106 	(void)setlocale(LC_ALL, "");
107 
108 	red = (n = strlen(argv[0])) > 2 && argv[0][n - 3] == 'r';
109 top:
110 	while ((c = getopt(argc, argv, "p:sx")) != -1)
111 		switch(c) {
112 		case 'p':				/* set prompt */
113 			prompt = optarg;
114 			break;
115 		case 's':				/* run script */
116 			scripted = 1;
117 			break;
118 		case 'x':				/* use crypt */
119 			fprintf(stderr, "crypt unavailable\n?\n");
120 			break;
121 
122 		default:
123 			fprintf(stderr, usage, red ? "red" : "ed");
124 			exit(1);
125 		}
126 	argv += optind;
127 	argc -= optind;
128 	if (argc && **argv == '-') {
129 		scripted = 1;
130 		if (argc > 1) {
131 			optind = 1;
132 			goto top;
133 		}
134 		argv++;
135 		argc--;
136 	}
137 	/* assert: reliable signals! */
138 #ifdef SIGWINCH
139 	handle_winch(SIGWINCH);
140 	if (isatty(0)) signal(SIGWINCH, handle_winch);
141 #endif
142 	signal(SIGHUP, signal_hup);
143 	signal(SIGQUIT, SIG_IGN);
144 	signal(SIGINT, signal_int);
145 #ifdef _POSIX_SOURCE
146 	if ((status = sigsetjmp(env, 1)))
147 #else
148 	if ((status = setjmp(env)))
149 #endif
150 	{
151 		fputs("\n?\n", stderr);
152 		errmsg = "interrupt";
153 	} else {
154 		init_buffers();
155 		sigactive = 1;			/* enable signal handlers */
156 		if (argc && **argv && is_legal_filename(*argv)) {
157 			if (read_file(*argv, 0) < 0 && !isatty(0))
158 				quit(2);
159 			else if (**argv != '!')
160 				if (strlcpy(old_filename, *argv, sizeof(old_filename))
161 				    >= sizeof(old_filename))
162 					quit(2);
163 		} else if (argc) {
164 			fputs("?\n", stderr);
165 			if (**argv == '\0')
166 				errmsg = "invalid filename";
167 			if (!isatty(0))
168 				quit(2);
169 		}
170 	}
171 	for (;;) {
172 		if (status < 0 && garrulous)
173 			fprintf(stderr, "%s\n", errmsg);
174 		if (prompt) {
175 			printf("%s", prompt);
176 			fflush(stdout);
177 		}
178 		if ((n = get_tty_line()) < 0) {
179 			status = ERR;
180 			continue;
181 		} else if (n == 0) {
182 			if (modified && !scripted) {
183 				fputs("?\n", stderr);
184 				errmsg = "warning: file modified";
185 				if (!isatty(0)) {
186 					if (garrulous)
187 						fprintf(stderr,
188 						    "script, line %d: %s\n",
189 						    lineno, errmsg);
190 					quit(2);
191 				}
192 				clearerr(stdin);
193 				modified = 0;
194 				status = EMOD;
195 				continue;
196 			} else
197 				quit(0);
198 		} else if (ibuf[n - 1] != '\n') {
199 			/* discard line */
200 			errmsg = "unexpected end-of-file";
201 			clearerr(stdin);
202 			status = ERR;
203 			continue;
204 		}
205 		isglobal = 0;
206 		if ((status = extract_addr_range()) >= 0 &&
207 		    (status = exec_command()) >= 0)
208 			if (!status ||
209 			    (status = display_lines(current_addr, current_addr,
210 			        status)) >= 0)
211 				continue;
212 		switch (status) {
213 		case EOF:
214 			quit(0);
215 		case EMOD:
216 			modified = 0;
217 			fputs("?\n", stderr);		/* give warning */
218 			errmsg = "warning: file modified";
219 			if (!isatty(0)) {
220 				if (garrulous)
221 					fprintf(stderr, "script, line %d: %s\n",
222 					    lineno, errmsg);
223 				quit(2);
224 			}
225 			break;
226 		case FATAL:
227 			if (!isatty(0)) {
228 				if (garrulous)
229 					fprintf(stderr, "script, line %d: %s\n",
230 					    lineno, errmsg);
231 			} else if (garrulous)
232 				fprintf(stderr, "%s\n", errmsg);
233 			quit(3);
234 		default:
235 			fputs("?\n", stderr);
236 			if (!isatty(0)) {
237 				if (garrulous)
238 					fprintf(stderr, "script, line %d: %s\n",
239 					    lineno, errmsg);
240 				quit(2);
241 			}
242 			break;
243 		}
244 	}
245 	/*NOTREACHED*/
246 }
247 
248 long first_addr, second_addr;
249 static long addr_cnt;
250 
251 /* extract_addr_range: get line addresses from the command buffer until an
252    illegal address is seen; return status */
253 int
254 extract_addr_range(void)
255 {
256 	long addr;
257 
258 	addr_cnt = 0;
259 	first_addr = second_addr = current_addr;
260 	while ((addr = next_addr()) >= 0) {
261 		addr_cnt++;
262 		first_addr = second_addr;
263 		second_addr = addr;
264 		if (*ibufp != ',' && *ibufp != ';')
265 			break;
266 		else if (*ibufp++ == ';')
267 			current_addr = addr;
268 	}
269 	if ((addr_cnt = min(addr_cnt, 2)) == 1 || second_addr != addr)
270 		first_addr = second_addr;
271 	return (addr == ERR) ? ERR : 0;
272 }
273 
274 
275 #define SKIP_BLANKS() while (isspace((unsigned char)*ibufp) && *ibufp != '\n') ibufp++
276 
277 #define MUST_BE_FIRST() do {					\
278 	if (!first) {						\
279 		errmsg = "invalid address";			\
280 		return ERR;					\
281 	}							\
282 } while (0)
283 
284 /*  next_addr: return the next line address in the command buffer */
285 long
286 next_addr(void)
287 {
288 	const char *hd;
289 	long addr = current_addr;
290 	long n;
291 	int first = 1;
292 	int c;
293 
294 	SKIP_BLANKS();
295 	for (hd = ibufp;; first = 0)
296 		switch (c = *ibufp) {
297 		case '+':
298 		case '\t':
299 		case ' ':
300 		case '-':
301 		case '^':
302 			ibufp++;
303 			SKIP_BLANKS();
304 			if (isdigit((unsigned char)*ibufp)) {
305 				STRTOL(n, ibufp);
306 				addr += (c == '-' || c == '^') ? -n : n;
307 			} else if (!isspace((unsigned char)c))
308 				addr += (c == '-' || c == '^') ? -1 : 1;
309 			break;
310 		case '0': case '1': case '2':
311 		case '3': case '4': case '5':
312 		case '6': case '7': case '8': case '9':
313 			MUST_BE_FIRST();
314 			STRTOL(addr, ibufp);
315 			break;
316 		case '.':
317 		case '$':
318 			MUST_BE_FIRST();
319 			ibufp++;
320 			addr = (c == '.') ? current_addr : addr_last;
321 			break;
322 		case '/':
323 		case '?':
324 			MUST_BE_FIRST();
325 			if ((addr = get_matching_node_addr(
326 			    get_compiled_pattern(), c == '/')) < 0)
327 				return ERR;
328 			else if (c == *ibufp)
329 				ibufp++;
330 			break;
331 		case '\'':
332 			MUST_BE_FIRST();
333 			ibufp++;
334 			if ((addr = get_marked_node_addr(*ibufp++)) < 0)
335 				return ERR;
336 			break;
337 		case '%':
338 		case ',':
339 		case ';':
340 			if (first) {
341 				ibufp++;
342 				addr_cnt++;
343 				second_addr = (c == ';') ? current_addr : 1;
344 				if ((addr = next_addr()) < 0)
345 					addr = addr_last;
346 				break;
347 			}
348 			/* FALLTHROUGH */
349 		default:
350 			if (ibufp == hd)
351 				return EOF;
352 			else if (addr < 0 || addr_last < addr) {
353 				errmsg = "invalid address";
354 				return ERR;
355 			} else
356 				return addr;
357 		}
358 	/* NOTREACHED */
359 }
360 
361 
362 #ifdef BACKWARDS
363 /* GET_THIRD_ADDR: get a legal address from the command buffer */
364 #define GET_THIRD_ADDR(addr) \
365 { \
366 	long ol1, ol2; \
367 \
368 	ol1 = first_addr, ol2 = second_addr; \
369 	if (extract_addr_range() < 0) \
370 		return ERR; \
371 	else if (addr_cnt == 0) { \
372 		errmsg = "destination expected"; \
373 		return ERR; \
374 	} else if (second_addr < 0 || addr_last < second_addr) { \
375 		errmsg = "invalid address"; \
376 		return ERR; \
377 	} \
378 	addr = second_addr; \
379 	first_addr = ol1, second_addr = ol2; \
380 }
381 #else	/* BACKWARDS */
382 /* GET_THIRD_ADDR: get a legal address from the command buffer */
383 #define GET_THIRD_ADDR(addr) \
384 { \
385 	long ol1, ol2; \
386 \
387 	ol1 = first_addr, ol2 = second_addr; \
388 	if (extract_addr_range() < 0) \
389 		return ERR; \
390 	if (second_addr < 0 || addr_last < second_addr) { \
391 		errmsg = "invalid address"; \
392 		return ERR; \
393 	} \
394 	addr = second_addr; \
395 	first_addr = ol1, second_addr = ol2; \
396 }
397 #endif
398 
399 
400 /* GET_COMMAND_SUFFIX: verify the command suffix in the command buffer */
401 #define GET_COMMAND_SUFFIX() { \
402 	int done = 0; \
403 	do { \
404 		switch(*ibufp) { \
405 		case 'p': \
406 			gflag |= GPR, ibufp++; \
407 			break; \
408 		case 'l': \
409 			gflag |= GLS, ibufp++; \
410 			break; \
411 		case 'n': \
412 			gflag |= GNP, ibufp++; \
413 			break; \
414 		default: \
415 			done++; \
416 		} \
417 	} while (!done); \
418 	if (*ibufp++ != '\n') { \
419 		errmsg = "invalid command suffix"; \
420 		return ERR; \
421 	} \
422 }
423 
424 
425 /* sflags */
426 #define SGG 001		/* complement previous global substitute suffix */
427 #define SGP 002		/* complement previous print suffix */
428 #define SGR 004		/* use last regex instead of last pat */
429 #define SGF 010		/* repeat last substitution */
430 
431 int patlock = 0;	/* if set, pattern not freed by get_compiled_pattern() */
432 
433 long rows = 22;		/* scroll length: ws_row - 2 */
434 
435 /* exec_command: execute the next command in command buffer; return print
436    request, if any */
437 int
438 exec_command(void)
439 {
440 	static pattern_t *pat = NULL;
441 	static int sgflag = 0;
442 	static long sgnum = 0;
443 
444 	pattern_t *tpat;
445 	char *fnp;
446 	int gflag = 0;
447 	int sflags = 0;
448 	long addr = 0;
449 	int n = 0;
450 	int c;
451 
452 	SKIP_BLANKS();
453 	switch(c = *ibufp++) {
454 	case 'a':
455 		GET_COMMAND_SUFFIX();
456 		if (!isglobal) clear_undo_stack();
457 		if (append_lines(second_addr) < 0)
458 			return ERR;
459 		break;
460 	case 'c':
461 		if (check_addr_range(current_addr, current_addr) < 0)
462 			return ERR;
463 		GET_COMMAND_SUFFIX();
464 		if (!isglobal) clear_undo_stack();
465 		if (delete_lines(first_addr, second_addr) < 0 ||
466 		    append_lines(current_addr) < 0)
467 			return ERR;
468 		break;
469 	case 'd':
470 		if (check_addr_range(current_addr, current_addr) < 0)
471 			return ERR;
472 		GET_COMMAND_SUFFIX();
473 		if (!isglobal) clear_undo_stack();
474 		if (delete_lines(first_addr, second_addr) < 0)
475 			return ERR;
476 		else if ((addr = INC_MOD(current_addr, addr_last)) != 0)
477 			current_addr = addr;
478 		break;
479 	case 'e':
480 		if (modified && !scripted)
481 			return EMOD;
482 		/* FALLTHROUGH */
483 	case 'E':
484 		if (addr_cnt > 0) {
485 			errmsg = "unexpected address";
486 			return ERR;
487 		} else if (!isspace((unsigned char)*ibufp)) {
488 			errmsg = "unexpected command suffix";
489 			return ERR;
490 		} else if ((fnp = get_filename()) == NULL)
491 			return ERR;
492 		GET_COMMAND_SUFFIX();
493 		if (delete_lines(1, addr_last) < 0)
494 			return ERR;
495 		clear_undo_stack();
496 		if (close_sbuf() < 0)
497 			return ERR;
498 		else if (open_sbuf() < 0)
499 			return FATAL;
500 		if (*fnp && *fnp != '!')
501 			 strlcpy(old_filename, fnp, PATH_MAX);
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)
529 			strlcpy(old_filename, fnp, PATH_MAX);
530 		printf("%s\n", strip_escapes(old_filename));
531 		break;
532 	case 'g':
533 	case 'v':
534 	case 'G':
535 	case 'V':
536 		if (isglobal) {
537 			errmsg = "cannot nest global commands";
538 			return ERR;
539 		} else if (check_addr_range(1, addr_last) < 0)
540 			return ERR;
541 		else if (build_active_list(c == 'g' || c == 'G') < 0)
542 			return ERR;
543 		else if ((n = (c == 'G' || c == 'V')))
544 			GET_COMMAND_SUFFIX();
545 		isglobal++;
546 		if (exec_global(n, gflag) < 0)
547 			return ERR;
548 		break;
549 	case 'h':
550 		if (addr_cnt > 0) {
551 			errmsg = "unexpected address";
552 			return ERR;
553 		}
554 		GET_COMMAND_SUFFIX();
555 		if (*errmsg) fprintf(stderr, "%s\n", errmsg);
556 		break;
557 	case 'H':
558 		if (addr_cnt > 0) {
559 			errmsg = "unexpected address";
560 			return ERR;
561 		}
562 		GET_COMMAND_SUFFIX();
563 		if ((garrulous = 1 - garrulous) && *errmsg)
564 			fprintf(stderr, "%s\n", errmsg);
565 		break;
566 	case 'i':
567 		if (second_addr == 0) {
568 			errmsg = "invalid address";
569 			return ERR;
570 		}
571 		GET_COMMAND_SUFFIX();
572 		if (!isglobal) clear_undo_stack();
573 		if (append_lines(second_addr - 1) < 0)
574 			return ERR;
575 		break;
576 	case 'j':
577 		if (check_addr_range(current_addr, current_addr + 1) < 0)
578 			return ERR;
579 		GET_COMMAND_SUFFIX();
580 		if (!isglobal) clear_undo_stack();
581 		if (first_addr != second_addr &&
582 		    join_lines(first_addr, second_addr) < 0)
583 			return ERR;
584 		break;
585 	case 'k':
586 		c = *ibufp++;
587 		if (second_addr == 0) {
588 			errmsg = "invalid address";
589 			return ERR;
590 		}
591 		GET_COMMAND_SUFFIX();
592 		if (mark_line_node(get_addressed_line_node(second_addr), c) < 0)
593 			return ERR;
594 		break;
595 	case 'l':
596 		if (check_addr_range(current_addr, current_addr) < 0)
597 			return ERR;
598 		GET_COMMAND_SUFFIX();
599 		if (display_lines(first_addr, second_addr, gflag | GLS) < 0)
600 			return ERR;
601 		gflag = 0;
602 		break;
603 	case 'm':
604 		if (check_addr_range(current_addr, current_addr) < 0)
605 			return ERR;
606 		GET_THIRD_ADDR(addr);
607 		if (first_addr <= addr && addr < second_addr) {
608 			errmsg = "invalid destination";
609 			return ERR;
610 		}
611 		GET_COMMAND_SUFFIX();
612 		if (!isglobal) clear_undo_stack();
613 		if (move_lines(addr) < 0)
614 			return ERR;
615 		break;
616 	case 'n':
617 		if (check_addr_range(current_addr, current_addr) < 0)
618 			return ERR;
619 		GET_COMMAND_SUFFIX();
620 		if (display_lines(first_addr, second_addr, gflag | GNP) < 0)
621 			return ERR;
622 		gflag = 0;
623 		break;
624 	case 'p':
625 		if (check_addr_range(current_addr, current_addr) < 0)
626 			return ERR;
627 		GET_COMMAND_SUFFIX();
628 		if (display_lines(first_addr, second_addr, gflag | GPR) < 0)
629 			return ERR;
630 		gflag = 0;
631 		break;
632 	case 'P':
633 		if (addr_cnt > 0) {
634 			errmsg = "unexpected address";
635 			return ERR;
636 		}
637 		GET_COMMAND_SUFFIX();
638 		prompt = prompt ? NULL : optarg ? optarg : dps;
639 		break;
640 	case 'q':
641 	case 'Q':
642 		if (addr_cnt > 0) {
643 			errmsg = "unexpected address";
644 			return ERR;
645 		}
646 		GET_COMMAND_SUFFIX();
647 		gflag =  (modified && !scripted && c == 'q') ? EMOD : EOF;
648 		break;
649 	case 'r':
650 		if (!isspace((unsigned char)*ibufp)) {
651 			errmsg = "unexpected command suffix";
652 			return ERR;
653 		} else if (addr_cnt == 0)
654 			second_addr = addr_last;
655 		if ((fnp = get_filename()) == NULL)
656 			return ERR;
657 		GET_COMMAND_SUFFIX();
658 		if (!isglobal) clear_undo_stack();
659 		if (*old_filename == '\0' && *fnp != '!')
660 			strlcpy(old_filename, fnp, PATH_MAX);
661 #ifdef BACKWARDS
662 		if (*fnp == '\0' && *old_filename == '\0') {
663 			errmsg = "no current filename";
664 			return ERR;
665 		}
666 #endif
667 		if ((addr = read_file(*fnp ? fnp : old_filename, second_addr)) < 0)
668 			return ERR;
669 		else if (addr && addr != addr_last)
670 			modified = 1;
671 		break;
672 	case 's':
673 		do {
674 			switch(*ibufp) {
675 			case '\n':
676 				sflags |=SGF;
677 				break;
678 			case 'g':
679 				sflags |= SGG;
680 				ibufp++;
681 				break;
682 			case 'p':
683 				sflags |= SGP;
684 				ibufp++;
685 				break;
686 			case 'r':
687 				sflags |= SGR;
688 				ibufp++;
689 				break;
690 			case '0': case '1': case '2': case '3': case '4':
691 			case '5': case '6': case '7': case '8': case '9':
692 				STRTOL(sgnum, ibufp);
693 				sflags |= SGF;
694 				sgflag &= ~GSG;		/* override GSG */
695 				break;
696 			default:
697 				if (sflags) {
698 					errmsg = "invalid command suffix";
699 					return ERR;
700 				}
701 			}
702 		} while (sflags && *ibufp != '\n');
703 		if (sflags && !pat) {
704 			errmsg = "no previous substitution";
705 			return ERR;
706 		} else if (sflags & SGG)
707 			sgnum = 0;		/* override numeric arg */
708 		if (*ibufp != '\n' && *(ibufp + 1) == '\n') {
709 			errmsg = "invalid pattern delimiter";
710 			return ERR;
711 		}
712 		tpat = pat;
713 		SPL1();
714 		if ((!sflags || (sflags & SGR)) &&
715 		    (tpat = get_compiled_pattern()) == NULL) {
716 		 	SPL0();
717 			return ERR;
718 		} else if (tpat != pat) {
719 			if (pat) {
720 				regfree(pat);
721 				free(pat);
722 			}
723 			pat = tpat;
724 			patlock = 1;		/* reserve pattern */
725 		}
726 		SPL0();
727 		if (!sflags && extract_subst_tail(&sgflag, &sgnum) < 0)
728 			return ERR;
729 		else if (isglobal)
730 			sgflag |= GLB;
731 		else
732 			sgflag &= ~GLB;
733 		if (sflags & SGG)
734 			sgflag ^= GSG;
735 		if (sflags & SGP)
736 			sgflag ^= GPR, sgflag &= ~(GLS | GNP);
737 		do {
738 			switch(*ibufp) {
739 			case 'p':
740 				sgflag |= GPR, ibufp++;
741 				break;
742 			case 'l':
743 				sgflag |= GLS, ibufp++;
744 				break;
745 			case 'n':
746 				sgflag |= GNP, ibufp++;
747 				break;
748 			default:
749 				n++;
750 			}
751 		} while (!n);
752 		if (check_addr_range(current_addr, current_addr) < 0)
753 			return ERR;
754 		GET_COMMAND_SUFFIX();
755 		if (!isglobal) clear_undo_stack();
756 		if (search_and_replace(pat, sgflag, sgnum) < 0)
757 			return ERR;
758 		break;
759 	case 't':
760 		if (check_addr_range(current_addr, current_addr) < 0)
761 			return ERR;
762 		GET_THIRD_ADDR(addr);
763 		GET_COMMAND_SUFFIX();
764 		if (!isglobal) clear_undo_stack();
765 		if (copy_lines(addr) < 0)
766 			return ERR;
767 		break;
768 	case 'u':
769 		if (addr_cnt > 0) {
770 			errmsg = "unexpected address";
771 			return ERR;
772 		}
773 		GET_COMMAND_SUFFIX();
774 		if (pop_undo_stack() < 0)
775 			return ERR;
776 		break;
777 	case 'w':
778 	case 'W':
779 		if ((n = *ibufp) == 'q' || n == 'Q') {
780 			gflag = EOF;
781 			ibufp++;
782 		}
783 		if (!isspace((unsigned char)*ibufp)) {
784 			errmsg = "unexpected command suffix";
785 			return ERR;
786 		} else if ((fnp = get_filename()) == NULL)
787 			return ERR;
788 		if (addr_cnt == 0 && !addr_last)
789 			first_addr = second_addr = 0;
790 		else if (check_addr_range(1, addr_last) < 0)
791 			return ERR;
792 		GET_COMMAND_SUFFIX();
793 		if (*old_filename == '\0' && *fnp != '!')
794 			strlcpy(old_filename, fnp, PATH_MAX);
795 #ifdef BACKWARDS
796 		if (*fnp == '\0' && *old_filename == '\0') {
797 			errmsg = "no current filename";
798 			return ERR;
799 		}
800 #endif
801 		if ((addr = write_file(*fnp ? fnp : old_filename,
802 		    (c == 'W') ? "a" : "w", first_addr, second_addr)) < 0)
803 			return ERR;
804 		else if (addr == addr_last && *fnp != '!')
805 			modified = 0;
806 		else if (modified && !scripted && n == 'q')
807 			gflag = EMOD;
808 		break;
809 	case 'x':
810 		if (addr_cnt > 0) {
811 			errmsg = "unexpected address";
812 			return ERR;
813 		}
814 		GET_COMMAND_SUFFIX();
815 		errmsg = "crypt unavailable";
816 		return ERR;
817 	case 'z':
818 #ifdef BACKWARDS
819 		if (check_addr_range(first_addr = 1, current_addr + 1) < 0)
820 #else
821 		if (check_addr_range(first_addr = 1, current_addr + !isglobal) < 0)
822 #endif
823 			return ERR;
824 		else if ('0' < *ibufp && *ibufp <= '9')
825 			STRTOL(rows, ibufp);
826 		GET_COMMAND_SUFFIX();
827 		if (display_lines(second_addr, min(addr_last,
828 		    second_addr + rows), gflag) < 0)
829 			return ERR;
830 		gflag = 0;
831 		break;
832 	case '=':
833 		GET_COMMAND_SUFFIX();
834 		printf("%ld\n", addr_cnt ? second_addr : addr_last);
835 		break;
836 	case '!':
837 		if (addr_cnt > 0) {
838 			errmsg = "unexpected address";
839 			return ERR;
840 		} else if ((sflags = get_shell_command()) < 0)
841 			return ERR;
842 		GET_COMMAND_SUFFIX();
843 		if (sflags) printf("%s\n", shcmd + 1);
844 		system(shcmd + 1);
845 		if (!scripted) printf("!\n");
846 		break;
847 	case '\n':
848 #ifdef BACKWARDS
849 		if (check_addr_range(first_addr = 1, current_addr + 1) < 0
850 #else
851 		if (check_addr_range(first_addr = 1, current_addr + !isglobal) < 0
852 #endif
853 		 || display_lines(second_addr, second_addr, 0) < 0)
854 			return ERR;
855 		break;
856 	default:
857 		errmsg = "unknown command";
858 		return ERR;
859 	}
860 	return gflag;
861 }
862 
863 
864 /* check_addr_range: return status of address range check */
865 int
866 check_addr_range(long n, long m)
867 {
868 	if (addr_cnt == 0) {
869 		first_addr = n;
870 		second_addr = m;
871 	}
872 	if (first_addr > second_addr || 1 > first_addr ||
873 	    second_addr > addr_last) {
874 		errmsg = "invalid address";
875 		return ERR;
876 	}
877 	return 0;
878 }
879 
880 
881 /* get_matching_node_addr: return the address of the next line matching a
882    pattern in a given direction.  wrap around begin/end of editor buffer if
883    necessary */
884 long
885 get_matching_node_addr(pattern_t *pat, int dir)
886 {
887 	char *s;
888 	long n = current_addr;
889 	line_t *lp;
890 
891 	if (!pat) return ERR;
892 	do {
893 	       if ((n = dir ? INC_MOD(n, addr_last) : DEC_MOD(n, addr_last))) {
894 			lp = get_addressed_line_node(n);
895 			if ((s = get_sbuf_line(lp)) == NULL)
896 				return ERR;
897 			if (isbinary)
898 				NUL_TO_NEWLINE(s, lp->len);
899 			if (!regexec(pat, s, 0, NULL, 0))
900 				return n;
901 	       }
902 	} while (n != current_addr);
903 	errmsg = "no match";
904 	return  ERR;
905 }
906 
907 
908 /* get_filename: return pointer to copy of filename in the command buffer */
909 char *
910 get_filename(void)
911 {
912 	static char *file = NULL;
913 	static int filesz = 0;
914 
915 	int n;
916 
917 	if (*ibufp != '\n') {
918 		SKIP_BLANKS();
919 		if (*ibufp == '\n') {
920 			errmsg = "invalid filename";
921 			return NULL;
922 		} else if ((ibufp = get_extended_line(&n, 1)) == NULL)
923 			return NULL;
924 		else if (*ibufp == '!') {
925 			ibufp++;
926 			if ((n = get_shell_command()) < 0)
927 				return NULL;
928 			if (n)
929 				printf("%s\n", shcmd + 1);
930 			return shcmd;
931 		} else if (n > PATH_MAX - 1) {
932 			errmsg = "filename too long";
933 			return  NULL;
934 		}
935 	}
936 #ifndef BACKWARDS
937 	else if (*old_filename == '\0') {
938 		errmsg = "no current filename";
939 		return  NULL;
940 	}
941 #endif
942 	REALLOC(file, filesz, PATH_MAX, NULL);
943 	for (n = 0; *ibufp != '\n';)
944 		file[n++] = *ibufp++;
945 	file[n] = '\0';
946 	return is_legal_filename(file) ? file : NULL;
947 }
948 
949 
950 /* get_shell_command: read a shell command from stdin; return substitution
951    status */
952 int
953 get_shell_command(void)
954 {
955 	static char *buf = NULL;
956 	static int n = 0;
957 
958 	char *s;			/* substitution char pointer */
959 	int i = 0;
960 	int j = 0;
961 
962 	if (red) {
963 		errmsg = "shell access restricted";
964 		return ERR;
965 	} else if ((s = ibufp = get_extended_line(&j, 1)) == NULL)
966 		return ERR;
967 	REALLOC(buf, n, j + 1, ERR);
968 	buf[i++] = '!';			/* prefix command w/ bang */
969 	while (*ibufp != '\n')
970 		switch (*ibufp) {
971 		default:
972 			REALLOC(buf, n, i + 2, ERR);
973 			buf[i++] = *ibufp;
974 			if (*ibufp++ == '\\')
975 				buf[i++] = *ibufp++;
976 			break;
977 		case '!':
978 			if (s != ibufp) {
979 				REALLOC(buf, n, i + 1, ERR);
980 				buf[i++] = *ibufp++;
981 			}
982 #ifdef BACKWARDS
983 			else if (shcmd == NULL || *(shcmd + 1) == '\0')
984 #else
985 			else if (shcmd == NULL)
986 #endif
987 			{
988 				errmsg = "no previous command";
989 				return ERR;
990 			} else {
991 				REALLOC(buf, n, i + shcmdi, ERR);
992 				for (s = shcmd + 1; s < shcmd + shcmdi;)
993 					buf[i++] = *s++;
994 				s = ibufp++;
995 			}
996 			break;
997 		case '%':
998 			if (*old_filename  == '\0') {
999 				errmsg = "no current filename";
1000 				return ERR;
1001 			}
1002 			j = strlen(s = strip_escapes(old_filename));
1003 			REALLOC(buf, n, i + j, ERR);
1004 			while (j--)
1005 				buf[i++] = *s++;
1006 			s = ibufp++;
1007 			break;
1008 		}
1009 	REALLOC(shcmd, shcmdsz, i + 1, ERR);
1010 	memcpy(shcmd, buf, i);
1011 	shcmd[shcmdi = i] = '\0';
1012 	return *s == '!' || *s == '%';
1013 }
1014 
1015 
1016 /* append_lines: insert text from stdin to after line n; stop when either a
1017    single period is read or EOF; return status */
1018 int
1019 append_lines(long n)
1020 {
1021 	int l;
1022 	const char *lp = ibuf;
1023 	const char *eot;
1024 	undo_t *up = NULL;
1025 
1026 	for (current_addr = n;;) {
1027 		if (!isglobal) {
1028 			if ((l = get_tty_line()) < 0)
1029 				return ERR;
1030 			else if (l == 0 || ibuf[l - 1] != '\n') {
1031 				clearerr(stdin);
1032 				return  l ? EOF : 0;
1033 			}
1034 			lp = ibuf;
1035 		} else if (*(lp = ibufp) == '\0')
1036 			return 0;
1037 		else {
1038 			while (*ibufp++ != '\n')
1039 				;
1040 			l = ibufp - lp;
1041 		}
1042 		if (l == 2 && lp[0] == '.' && lp[1] == '\n') {
1043 			return 0;
1044 		}
1045 		eot = lp + l;
1046 		SPL1();
1047 		do {
1048 			if ((lp = put_sbuf_line(lp)) == NULL) {
1049 				SPL0();
1050 				return ERR;
1051 			} else if (up)
1052 				up->t = get_addressed_line_node(current_addr);
1053 			else if ((up = push_undo_stack(UADD, current_addr,
1054 			    current_addr)) == NULL) {
1055 				SPL0();
1056 				return ERR;
1057 			}
1058 		} while (lp != eot);
1059 		modified = 1;
1060 		SPL0();
1061 	}
1062 	/* NOTREACHED */
1063 }
1064 
1065 
1066 /* join_lines: replace a range of lines with the joined text of those lines */
1067 int
1068 join_lines(long from, long to)
1069 {
1070 	static char *buf = NULL;
1071 	static int n;
1072 
1073 	char *s;
1074 	int size = 0;
1075 	line_t *bp, *ep;
1076 
1077 	ep = get_addressed_line_node(INC_MOD(to, addr_last));
1078 	bp = get_addressed_line_node(from);
1079 	for (; bp != ep; bp = bp->q_forw) {
1080 		if ((s = get_sbuf_line(bp)) == NULL)
1081 			return ERR;
1082 		REALLOC(buf, n, size + bp->len, ERR);
1083 		memcpy(buf + size, s, bp->len);
1084 		size += bp->len;
1085 	}
1086 	REALLOC(buf, n, size + 2, ERR);
1087 	memcpy(buf + size, "\n", 2);
1088 	if (delete_lines(from, to) < 0)
1089 		return ERR;
1090 	current_addr = from - 1;
1091 	SPL1();
1092 	if (put_sbuf_line(buf) == NULL ||
1093 	    push_undo_stack(UADD, current_addr, current_addr) == NULL) {
1094 		SPL0();
1095 		return ERR;
1096 	}
1097 	modified = 1;
1098 	SPL0();
1099 	return 0;
1100 }
1101 
1102 
1103 /* move_lines: move a range of lines */
1104 int
1105 move_lines(long addr)
1106 {
1107 	line_t *b1, *a1, *b2, *a2;
1108 	long n = INC_MOD(second_addr, addr_last);
1109 	long p = first_addr - 1;
1110 	int done = (addr == first_addr - 1 || addr == second_addr);
1111 
1112 	SPL1();
1113 	if (done) {
1114 		a2 = get_addressed_line_node(n);
1115 		b2 = get_addressed_line_node(p);
1116 		current_addr = second_addr;
1117 	} else if (push_undo_stack(UMOV, p, n) == NULL ||
1118 	    push_undo_stack(UMOV, addr, INC_MOD(addr, addr_last)) == NULL) {
1119 		SPL0();
1120 		return ERR;
1121 	} else {
1122 		a1 = get_addressed_line_node(n);
1123 		if (addr < first_addr) {
1124 			b1 = get_addressed_line_node(p);
1125 			b2 = get_addressed_line_node(addr);
1126 					/* this get_addressed_line_node last! */
1127 		} else {
1128 			b2 = get_addressed_line_node(addr);
1129 			b1 = get_addressed_line_node(p);
1130 					/* this get_addressed_line_node last! */
1131 		}
1132 		a2 = b2->q_forw;
1133 		REQUE(b2, b1->q_forw);
1134 		REQUE(a1->q_back, a2);
1135 		REQUE(b1, a1);
1136 		current_addr = addr + ((addr < first_addr) ?
1137 		    second_addr - first_addr + 1 : 0);
1138 	}
1139 	if (isglobal)
1140 		unset_active_nodes(b2->q_forw, a2);
1141 	modified = 1;
1142 	SPL0();
1143 	return 0;
1144 }
1145 
1146 
1147 /* copy_lines: copy a range of lines; return status */
1148 int
1149 copy_lines(long addr)
1150 {
1151 	line_t *lp, *np = get_addressed_line_node(first_addr);
1152 	undo_t *up = NULL;
1153 	long n = second_addr - first_addr + 1;
1154 	long m = 0;
1155 
1156 	current_addr = addr;
1157 	if (first_addr <= addr && addr < second_addr) {
1158 		n =  addr - first_addr + 1;
1159 		m = second_addr - addr;
1160 	}
1161 	for (; n > 0; n=m, m=0, np = get_addressed_line_node(current_addr + 1))
1162 		for (; n-- > 0; np = np->q_forw) {
1163 			SPL1();
1164 			if ((lp = dup_line_node(np)) == NULL) {
1165 				SPL0();
1166 				return ERR;
1167 			}
1168 			add_line_node(lp);
1169 			if (up)
1170 				up->t = lp;
1171 			else if ((up = push_undo_stack(UADD, current_addr,
1172 			    current_addr)) == NULL) {
1173 				SPL0();
1174 				return ERR;
1175 			}
1176 			modified = 1;
1177 			SPL0();
1178 		}
1179 	return 0;
1180 }
1181 
1182 
1183 /* delete_lines: delete a range of lines */
1184 int
1185 delete_lines(long from, long to)
1186 {
1187 	line_t *n, *p;
1188 
1189 	SPL1();
1190 	if (push_undo_stack(UDEL, from, to) == NULL) {
1191 		SPL0();
1192 		return ERR;
1193 	}
1194 	n = get_addressed_line_node(INC_MOD(to, addr_last));
1195 	p = get_addressed_line_node(from - 1);
1196 					/* this get_addressed_line_node last! */
1197 	if (isglobal)
1198 		unset_active_nodes(p->q_forw, n);
1199 	REQUE(p, n);
1200 	addr_last -= to - from + 1;
1201 	current_addr = from - 1;
1202 	modified = 1;
1203 	SPL0();
1204 	return 0;
1205 }
1206 
1207 
1208 /* display_lines: print a range of lines to stdout */
1209 int
1210 display_lines(long from, long to, int gflag)
1211 {
1212 	line_t *bp;
1213 	line_t *ep;
1214 	char *s;
1215 
1216 	if (!from) {
1217 		errmsg = "invalid address";
1218 		return ERR;
1219 	}
1220 	ep = get_addressed_line_node(INC_MOD(to, addr_last));
1221 	bp = get_addressed_line_node(from);
1222 	for (; bp != ep; bp = bp->q_forw) {
1223 		if ((s = get_sbuf_line(bp)) == NULL)
1224 			return ERR;
1225 		if (put_tty_line(s, bp->len, current_addr = from++, gflag) < 0)
1226 			return ERR;
1227 	}
1228 	return 0;
1229 }
1230 
1231 
1232 #define MAXMARK 26			/* max number of marks */
1233 
1234 static line_t *mark[MAXMARK];		/* line markers */
1235 static int markno;			/* line marker count */
1236 
1237 /* mark_line_node: set a line node mark */
1238 int
1239 mark_line_node(line_t *lp, int n)
1240 {
1241 	if (!islower((unsigned char)n)) {
1242 		errmsg = "invalid mark character";
1243 		return ERR;
1244 	} else if (mark[n - 'a'] == NULL)
1245 		markno++;
1246 	mark[n - 'a'] = lp;
1247 	return 0;
1248 }
1249 
1250 
1251 /* get_marked_node_addr: return address of a marked line */
1252 long
1253 get_marked_node_addr(int n)
1254 {
1255 	if (!islower((unsigned char)n)) {
1256 		errmsg = "invalid mark character";
1257 		return ERR;
1258 	}
1259 	return get_line_node_addr(mark[n - 'a']);
1260 }
1261 
1262 
1263 /* unmark_line_node: clear line node mark */
1264 void
1265 unmark_line_node(line_t *lp)
1266 {
1267 	int i;
1268 
1269 	for (i = 0; markno && i < MAXMARK; i++)
1270 		if (mark[i] == lp) {
1271 			mark[i] = NULL;
1272 			markno--;
1273 		}
1274 }
1275 
1276 
1277 /* dup_line_node: return a pointer to a copy of a line node */
1278 line_t *
1279 dup_line_node(line_t *lp)
1280 {
1281 	line_t *np;
1282 
1283 	if ((np = (line_t *) malloc(sizeof(line_t))) == NULL) {
1284 		fprintf(stderr, "%s\n", strerror(errno));
1285 		errmsg = "out of memory";
1286 		return NULL;
1287 	}
1288 	np->seek = lp->seek;
1289 	np->len = lp->len;
1290 	return np;
1291 }
1292 
1293 
1294 /* has_trailing_escape:  return the parity of escapes preceding a character
1295    in a string */
1296 int
1297 has_trailing_escape(char *s, char *t)
1298 {
1299     return (s == t || *(t - 1) != '\\') ? 0 : !has_trailing_escape(s, t - 1);
1300 }
1301 
1302 
1303 /* strip_escapes: return copy of escaped string of at most length PATH_MAX */
1304 char *
1305 strip_escapes(char *s)
1306 {
1307 	static char *file = NULL;
1308 	static int filesz = 0;
1309 
1310 	int i = 0;
1311 
1312 	REALLOC(file, filesz, PATH_MAX, NULL);
1313 	while (i < filesz - 1	/* Worry about a possible trailing escape */
1314 	       && (file[i++] = (*s == '\\') ? *++s : *s))
1315 		s++;
1316 	return file;
1317 }
1318 
1319 
1320 void
1321 signal_hup(int signo)
1322 {
1323 	if (mutex)
1324 		sigflags |= (1 << (signo - 1));
1325 	else
1326 		handle_hup(signo);
1327 }
1328 
1329 
1330 void
1331 signal_int(int signo)
1332 {
1333 	if (mutex)
1334 		sigflags |= (1 << (signo - 1));
1335 	else
1336 		handle_int(signo);
1337 }
1338 
1339 
1340 void
1341 handle_hup(int signo)
1342 {
1343 	char *hup = NULL;		/* hup filename */
1344 	char *s;
1345 	char ed_hup[] = "ed.hup";
1346 	size_t n;
1347 
1348 	if (!sigactive)
1349 		quit(1);
1350 	sigflags &= ~(1 << (signo - 1));
1351 	if (addr_last && write_file(ed_hup, "w", 1, addr_last) < 0 &&
1352 	    (s = getenv("HOME")) != NULL &&
1353 	    (n = strlen(s)) + 8 <= PATH_MAX &&	/* "ed.hup" + '/' */
1354 	    (hup = (char *) malloc(n + 10)) != NULL) {
1355 		strcpy(hup, s);
1356 		if (hup[n - 1] != '/')
1357 			hup[n] = '/', hup[n+1] = '\0';
1358 		strcat(hup, "ed.hup");
1359 		write_file(hup, "w", 1, addr_last);
1360 	}
1361 	quit(2);
1362 }
1363 
1364 
1365 void
1366 handle_int(int signo)
1367 {
1368 	if (!sigactive)
1369 		quit(1);
1370 	sigflags &= ~(1 << (signo - 1));
1371 #ifdef _POSIX_SOURCE
1372 	siglongjmp(env, -1);
1373 #else
1374 	longjmp(env, -1);
1375 #endif
1376 }
1377 
1378 
1379 int cols = 72;				/* wrap column */
1380 
1381 void
1382 handle_winch(int signo)
1383 {
1384 	int save_errno = errno;
1385 
1386 	struct winsize ws;		/* window size structure */
1387 
1388 	sigflags &= ~(1 << (signo - 1));
1389 	if (ioctl(0, TIOCGWINSZ, (char *) &ws) >= 0) {
1390 		if (ws.ws_row > 2) rows = ws.ws_row - 2;
1391 		if (ws.ws_col > 8) cols = ws.ws_col - 8;
1392 	}
1393 	errno = save_errno;
1394 }
1395 
1396 
1397 /* is_legal_filename: return a legal filename */
1398 int
1399 is_legal_filename(char *s)
1400 {
1401 	if (red && (*s == '!' || !strcmp(s, "..") || strchr(s, '/'))) {
1402 		errmsg = "shell access restricted";
1403 		return 0;
1404 	}
1405 	return 1;
1406 }
1407