xref: /freebsd/bin/ed/main.c (revision 8aac90f18aef7c9eea906c3ff9a001ca7b94f375)
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 /*
30  * CREDITS
31  *
32  *	This program is based on the editor algorithm described in
33  *	Brian W. Kernighan and P. J. Plauger's book "Software Tools
34  *	in Pascal," Addison-Wesley, 1981.
35  *
36  *	The buffering algorithm is attributed to Rodney Ruddock of
37  *	the University of Guelph, Guelph, Ontario.
38  *
39  */
40 
41 #include <sys/types.h>
42 
43 #include <sys/ioctl.h>
44 #include <sys/wait.h>
45 #include <ctype.h>
46 #include <locale.h>
47 #include <pwd.h>
48 #include <setjmp.h>
49 
50 #include "ed.h"
51 
52 
53 #ifdef _POSIX_SOURCE
54 static sigjmp_buf env;
55 #else
56 static jmp_buf env;
57 #endif
58 
59 /* static buffers */
60 char stdinbuf[1];		/* stdin buffer */
61 static char *shcmd;		/* shell command buffer */
62 static int shcmdsz;		/* shell command buffer size */
63 static int shcmdi;		/* shell command buffer index */
64 char *ibuf;			/* ed command-line buffer */
65 int ibufsz;			/* ed command-line buffer size */
66 char *ibufp;			/* pointer to ed command-line buffer */
67 
68 /* global flags */
69 static int garrulous = 0;	/* if set, print all error messages */
70 int isbinary;			/* if set, buffer contains ASCII NULs */
71 int isglobal;			/* if set, doing a global command */
72 int modified;			/* if set, buffer modified since last write */
73 int mutex = 0;			/* if set, signals set "sigflags" */
74 static int red = 0;		/* if set, restrict shell/directory access */
75 int scripted = 0;		/* if set, suppress diagnostics */
76 int sigflags = 0;		/* if set, signals received while mutex set */
77 static int sigactive = 0;	/* if set, signal handlers are enabled */
78 
79 static char old_filename[PATH_MAX] = ""; /* default filename */
80 long current_addr;		/* current address in editor buffer */
81 long addr_last;			/* last address in editor buffer */
82 int lineno;			/* script line number */
83 static const char *prompt;	/* command-line prompt */
84 static const char *dps = "*";	/* default command-line prompt */
85 
86 static const char *usage = "usage: %s [-] [-sx] [-p string] [file]\n";
87 
88 /* ed: line editor */
89 int
90 main(volatile int argc, char ** volatile argv)
91 {
92 	int c, n;
93 	long status = 0;
94 
95 	(void)setlocale(LC_ALL, "");
96 
97 	red = (n = strlen(argv[0])) > 2 && argv[0][n - 3] == 'r';
98 top:
99 	while ((c = getopt(argc, argv, "p:sx")) != -1)
100 		switch(c) {
101 		case 'p':				/* set prompt */
102 			prompt = optarg;
103 			break;
104 		case 's':				/* run script */
105 			scripted = 1;
106 			break;
107 		case 'x':				/* use crypt */
108 			fprintf(stderr, "crypt unavailable\n?\n");
109 			break;
110 
111 		default:
112 			fprintf(stderr, usage, red ? "red" : "ed");
113 			exit(1);
114 		}
115 	argv += optind;
116 	argc -= optind;
117 	if (argc && **argv == '-') {
118 		scripted = 1;
119 		if (argc > 1) {
120 			optind = 1;
121 			goto top;
122 		}
123 		argv++;
124 		argc--;
125 	}
126 	/* assert: reliable signals! */
127 #ifdef SIGWINCH
128 	handle_winch(SIGWINCH);
129 	if (isatty(0)) signal(SIGWINCH, handle_winch);
130 #endif
131 	signal(SIGHUP, signal_hup);
132 	signal(SIGQUIT, SIG_IGN);
133 	signal(SIGINT, signal_int);
134 #ifdef _POSIX_SOURCE
135 	if ((status = sigsetjmp(env, 1)))
136 #else
137 	if ((status = setjmp(env)))
138 #endif
139 	{
140 		fputs("\n?\n", stderr);
141 		errmsg = "interrupt";
142 	} else {
143 		init_buffers();
144 		sigactive = 1;			/* enable signal handlers */
145 		if (argc && **argv && is_legal_filename(*argv)) {
146 			if (read_file(*argv, 0) < 0 && !isatty(0))
147 				quit(2);
148 			else if (**argv != '!')
149 				if (strlcpy(old_filename, *argv, sizeof(old_filename))
150 				    >= sizeof(old_filename))
151 					quit(2);
152 		} else if (argc) {
153 			fputs("?\n", stderr);
154 			if (**argv == '\0')
155 				errmsg = "invalid filename";
156 			if (!isatty(0))
157 				quit(2);
158 		}
159 	}
160 	for (;;) {
161 		if (status < 0 && garrulous)
162 			fprintf(stderr, "%s\n", errmsg);
163 		if (prompt) {
164 			printf("%s", prompt);
165 			fflush(stdout);
166 		}
167 		if ((n = get_tty_line()) < 0) {
168 			status = ERR;
169 			continue;
170 		} else if (n == 0) {
171 			if (modified && !scripted) {
172 				fputs("?\n", stderr);
173 				errmsg = "warning: file modified";
174 				if (!isatty(0)) {
175 					if (garrulous)
176 						fprintf(stderr,
177 						    "script, line %d: %s\n",
178 						    lineno, errmsg);
179 					quit(2);
180 				}
181 				clearerr(stdin);
182 				modified = 0;
183 				status = EMOD;
184 				continue;
185 			} else
186 				quit(0);
187 		} else if (ibuf[n - 1] != '\n') {
188 			/* discard line */
189 			errmsg = "unexpected end-of-file";
190 			clearerr(stdin);
191 			status = ERR;
192 			continue;
193 		}
194 		isglobal = 0;
195 		if ((status = extract_addr_range()) >= 0 &&
196 		    (status = exec_command()) >= 0)
197 			if (!status ||
198 			    (status = display_lines(current_addr, current_addr,
199 			        status)) >= 0)
200 				continue;
201 		switch (status) {
202 		case EOF:
203 			quit(0);
204 		case EMOD:
205 			modified = 0;
206 			fputs("?\n", stderr);		/* give warning */
207 			errmsg = "warning: file modified";
208 			if (!isatty(0)) {
209 				if (garrulous)
210 					fprintf(stderr, "script, line %d: %s\n",
211 					    lineno, errmsg);
212 				quit(2);
213 			}
214 			break;
215 		case FATAL:
216 			if (!isatty(0)) {
217 				if (garrulous)
218 					fprintf(stderr, "script, line %d: %s\n",
219 					    lineno, errmsg);
220 			} else if (garrulous)
221 				fprintf(stderr, "%s\n", errmsg);
222 			quit(3);
223 		default:
224 			fputs("?\n", stderr);
225 			if (!isatty(0)) {
226 				if (garrulous)
227 					fprintf(stderr, "script, line %d: %s\n",
228 					    lineno, errmsg);
229 				quit(2);
230 			}
231 			break;
232 		}
233 	}
234 	/*NOTREACHED*/
235 }
236 
237 long first_addr, second_addr;
238 static long addr_cnt;
239 
240 /* extract_addr_range: get line addresses from the command buffer until an
241    illegal address is seen; return status */
242 int
243 extract_addr_range(void)
244 {
245 	long addr;
246 
247 	addr_cnt = 0;
248 	first_addr = second_addr = current_addr;
249 	while ((addr = next_addr()) >= 0) {
250 		addr_cnt++;
251 		first_addr = second_addr;
252 		second_addr = addr;
253 		if (*ibufp != ',' && *ibufp != ';')
254 			break;
255 		else if (*ibufp++ == ';')
256 			current_addr = addr;
257 	}
258 	if ((addr_cnt = min(addr_cnt, 2)) == 1 || second_addr != addr)
259 		first_addr = second_addr;
260 	return (addr == ERR) ? ERR : 0;
261 }
262 
263 
264 #define SKIP_BLANKS() while (isspace((unsigned char)*ibufp) && *ibufp != '\n') ibufp++
265 
266 #define MUST_BE_FIRST() do {					\
267 	if (!first) {						\
268 		errmsg = "invalid address";			\
269 		return ERR;					\
270 	}							\
271 } while (0)
272 
273 /*  next_addr: return the next line address in the command buffer */
274 long
275 next_addr(void)
276 {
277 	const char *hd;
278 	long addr = current_addr;
279 	long n;
280 	int first = 1;
281 	int c;
282 
283 	SKIP_BLANKS();
284 	for (hd = ibufp;; first = 0)
285 		switch (c = *ibufp) {
286 		case '+':
287 		case '\t':
288 		case ' ':
289 		case '-':
290 		case '^':
291 			ibufp++;
292 			SKIP_BLANKS();
293 			if (isdigit((unsigned char)*ibufp)) {
294 				STRTOL(n, ibufp);
295 				addr += (c == '-' || c == '^') ? -n : n;
296 			} else if (!isspace((unsigned char)c))
297 				addr += (c == '-' || c == '^') ? -1 : 1;
298 			break;
299 		case '0': case '1': case '2':
300 		case '3': case '4': case '5':
301 		case '6': case '7': case '8': case '9':
302 			MUST_BE_FIRST();
303 			STRTOL(addr, ibufp);
304 			break;
305 		case '.':
306 		case '$':
307 			MUST_BE_FIRST();
308 			ibufp++;
309 			addr = (c == '.') ? current_addr : addr_last;
310 			break;
311 		case '/':
312 		case '?':
313 			MUST_BE_FIRST();
314 			if ((addr = get_matching_node_addr(
315 			    get_compiled_pattern(), c == '/')) < 0)
316 				return ERR;
317 			else if (c == *ibufp)
318 				ibufp++;
319 			break;
320 		case '\'':
321 			MUST_BE_FIRST();
322 			ibufp++;
323 			if ((addr = get_marked_node_addr(*ibufp++)) < 0)
324 				return ERR;
325 			break;
326 		case '%':
327 		case ',':
328 		case ';':
329 			if (first) {
330 				ibufp++;
331 				addr_cnt++;
332 				second_addr = (c == ';') ? current_addr : 1;
333 				if ((addr = next_addr()) < 0)
334 					addr = addr_last;
335 				break;
336 			}
337 			/* FALLTHROUGH */
338 		default:
339 			if (ibufp == hd)
340 				return EOF;
341 			else if (addr < 0 || addr_last < addr) {
342 				errmsg = "invalid address";
343 				return ERR;
344 			} else
345 				return addr;
346 		}
347 	/* NOTREACHED */
348 }
349 
350 
351 #ifdef BACKWARDS
352 /* GET_THIRD_ADDR: get a legal address from the command buffer */
353 #define GET_THIRD_ADDR(addr) \
354 { \
355 	long ol1, ol2; \
356 \
357 	ol1 = first_addr, ol2 = second_addr; \
358 	if (extract_addr_range() < 0) \
359 		return ERR; \
360 	else if (addr_cnt == 0) { \
361 		errmsg = "destination expected"; \
362 		return ERR; \
363 	} else if (second_addr < 0 || addr_last < second_addr) { \
364 		errmsg = "invalid address"; \
365 		return ERR; \
366 	} \
367 	addr = second_addr; \
368 	first_addr = ol1, second_addr = ol2; \
369 }
370 #else	/* BACKWARDS */
371 /* GET_THIRD_ADDR: get a legal address from the command buffer */
372 #define GET_THIRD_ADDR(addr) \
373 { \
374 	long ol1, ol2; \
375 \
376 	ol1 = first_addr, ol2 = second_addr; \
377 	if (extract_addr_range() < 0) \
378 		return ERR; \
379 	if (second_addr < 0 || addr_last < second_addr) { \
380 		errmsg = "invalid address"; \
381 		return ERR; \
382 	} \
383 	addr = second_addr; \
384 	first_addr = ol1, second_addr = ol2; \
385 }
386 #endif
387 
388 
389 /* GET_COMMAND_SUFFIX: verify the command suffix in the command buffer */
390 #define GET_COMMAND_SUFFIX() { \
391 	int done = 0; \
392 	do { \
393 		switch(*ibufp) { \
394 		case 'p': \
395 			gflag |= GPR, ibufp++; \
396 			break; \
397 		case 'l': \
398 			gflag |= GLS, ibufp++; \
399 			break; \
400 		case 'n': \
401 			gflag |= GNP, ibufp++; \
402 			break; \
403 		default: \
404 			done++; \
405 		} \
406 	} while (!done); \
407 	if (*ibufp++ != '\n') { \
408 		errmsg = "invalid command suffix"; \
409 		return ERR; \
410 	} \
411 }
412 
413 
414 /* sflags */
415 #define SGG 001		/* complement previous global substitute suffix */
416 #define SGP 002		/* complement previous print suffix */
417 #define SGR 004		/* use last regex instead of last pat */
418 #define SGF 010		/* repeat last substitution */
419 
420 int patlock = 0;	/* if set, pattern not freed by get_compiled_pattern() */
421 
422 long rows = 22;		/* scroll length: ws_row - 2 */
423 
424 /* exec_command: execute the next command in command buffer; return print
425    request, if any */
426 int
427 exec_command(void)
428 {
429 	static pattern_t *pat = NULL;
430 	static int sgflag = 0;
431 	static long sgnum = 0;
432 
433 	pattern_t *tpat;
434 	char *fnp;
435 	int gflag = 0;
436 	int sflags = 0;
437 	long addr = 0;
438 	int n = 0;
439 	int c;
440 
441 	SKIP_BLANKS();
442 	switch(c = *ibufp++) {
443 	case 'a':
444 		GET_COMMAND_SUFFIX();
445 		if (!isglobal) clear_undo_stack();
446 		if (append_lines(second_addr) < 0)
447 			return ERR;
448 		break;
449 	case 'c':
450 		if (check_addr_range(current_addr, current_addr) < 0)
451 			return ERR;
452 		GET_COMMAND_SUFFIX();
453 		if (!isglobal) clear_undo_stack();
454 		if (delete_lines(first_addr, second_addr) < 0 ||
455 		    append_lines(current_addr) < 0)
456 			return ERR;
457 		break;
458 	case 'd':
459 		if (check_addr_range(current_addr, current_addr) < 0)
460 			return ERR;
461 		GET_COMMAND_SUFFIX();
462 		if (!isglobal) clear_undo_stack();
463 		if (delete_lines(first_addr, second_addr) < 0)
464 			return ERR;
465 		else if ((addr = INC_MOD(current_addr, addr_last)) != 0)
466 			current_addr = addr;
467 		break;
468 	case 'e':
469 		if (modified && !scripted)
470 			return EMOD;
471 		/* FALLTHROUGH */
472 	case 'E':
473 		if (addr_cnt > 0) {
474 			errmsg = "unexpected address";
475 			return ERR;
476 		} else if (!isspace((unsigned char)*ibufp)) {
477 			errmsg = "unexpected command suffix";
478 			return ERR;
479 		} else if ((fnp = get_filename()) == NULL)
480 			return ERR;
481 		GET_COMMAND_SUFFIX();
482 		if (delete_lines(1, addr_last) < 0)
483 			return ERR;
484 		clear_undo_stack();
485 		if (close_sbuf() < 0)
486 			return ERR;
487 		else if (open_sbuf() < 0)
488 			return FATAL;
489 		if (*fnp && *fnp != '!')
490 			 strlcpy(old_filename, fnp, PATH_MAX);
491 #ifdef BACKWARDS
492 		if (*fnp == '\0' && *old_filename == '\0') {
493 			errmsg = "no current filename";
494 			return ERR;
495 		}
496 #endif
497 		if (read_file(*fnp ? fnp : old_filename, 0) < 0)
498 			return ERR;
499 		clear_undo_stack();
500 		modified = 0;
501 		u_current_addr = u_addr_last = -1;
502 		break;
503 	case 'f':
504 		if (addr_cnt > 0) {
505 			errmsg = "unexpected address";
506 			return ERR;
507 		} else if (!isspace((unsigned char)*ibufp)) {
508 			errmsg = "unexpected command suffix";
509 			return ERR;
510 		} else if ((fnp = get_filename()) == NULL)
511 			return ERR;
512 		else if (*fnp == '!') {
513 			errmsg = "invalid redirection";
514 			return ERR;
515 		}
516 		GET_COMMAND_SUFFIX();
517 		if (*fnp)
518 			strlcpy(old_filename, fnp, PATH_MAX);
519 		printf("%s\n", strip_escapes(old_filename));
520 		break;
521 	case 'g':
522 	case 'v':
523 	case 'G':
524 	case 'V':
525 		if (isglobal) {
526 			errmsg = "cannot nest global commands";
527 			return ERR;
528 		} else if (check_addr_range(1, addr_last) < 0)
529 			return ERR;
530 		else if (build_active_list(c == 'g' || c == 'G') < 0)
531 			return ERR;
532 		else if ((n = (c == 'G' || c == 'V')))
533 			GET_COMMAND_SUFFIX();
534 		isglobal++;
535 		if (exec_global(n, gflag) < 0)
536 			return ERR;
537 		break;
538 	case 'h':
539 		if (addr_cnt > 0) {
540 			errmsg = "unexpected address";
541 			return ERR;
542 		}
543 		GET_COMMAND_SUFFIX();
544 		if (*errmsg) fprintf(stderr, "%s\n", errmsg);
545 		break;
546 	case 'H':
547 		if (addr_cnt > 0) {
548 			errmsg = "unexpected address";
549 			return ERR;
550 		}
551 		GET_COMMAND_SUFFIX();
552 		if ((garrulous = 1 - garrulous) && *errmsg)
553 			fprintf(stderr, "%s\n", errmsg);
554 		break;
555 	case 'i':
556 		if (second_addr == 0) {
557 			errmsg = "invalid address";
558 			return ERR;
559 		}
560 		GET_COMMAND_SUFFIX();
561 		if (!isglobal) clear_undo_stack();
562 		if (append_lines(second_addr - 1) < 0)
563 			return ERR;
564 		break;
565 	case 'j':
566 		if (check_addr_range(current_addr, current_addr + 1) < 0)
567 			return ERR;
568 		GET_COMMAND_SUFFIX();
569 		if (!isglobal) clear_undo_stack();
570 		if (first_addr != second_addr &&
571 		    join_lines(first_addr, second_addr) < 0)
572 			return ERR;
573 		break;
574 	case 'k':
575 		c = *ibufp++;
576 		if (second_addr == 0) {
577 			errmsg = "invalid address";
578 			return ERR;
579 		}
580 		GET_COMMAND_SUFFIX();
581 		if (mark_line_node(get_addressed_line_node(second_addr), c) < 0)
582 			return ERR;
583 		break;
584 	case 'l':
585 		if (check_addr_range(current_addr, current_addr) < 0)
586 			return ERR;
587 		GET_COMMAND_SUFFIX();
588 		if (display_lines(first_addr, second_addr, gflag | GLS) < 0)
589 			return ERR;
590 		gflag = 0;
591 		break;
592 	case 'm':
593 		if (check_addr_range(current_addr, current_addr) < 0)
594 			return ERR;
595 		GET_THIRD_ADDR(addr);
596 		if (first_addr <= addr && addr < second_addr) {
597 			errmsg = "invalid destination";
598 			return ERR;
599 		}
600 		GET_COMMAND_SUFFIX();
601 		if (!isglobal) clear_undo_stack();
602 		if (move_lines(addr) < 0)
603 			return ERR;
604 		break;
605 	case 'n':
606 		if (check_addr_range(current_addr, current_addr) < 0)
607 			return ERR;
608 		GET_COMMAND_SUFFIX();
609 		if (display_lines(first_addr, second_addr, gflag | GNP) < 0)
610 			return ERR;
611 		gflag = 0;
612 		break;
613 	case 'p':
614 		if (check_addr_range(current_addr, current_addr) < 0)
615 			return ERR;
616 		GET_COMMAND_SUFFIX();
617 		if (display_lines(first_addr, second_addr, gflag | GPR) < 0)
618 			return ERR;
619 		gflag = 0;
620 		break;
621 	case 'P':
622 		if (addr_cnt > 0) {
623 			errmsg = "unexpected address";
624 			return ERR;
625 		}
626 		GET_COMMAND_SUFFIX();
627 		prompt = prompt ? NULL : optarg ? optarg : dps;
628 		break;
629 	case 'q':
630 	case 'Q':
631 		if (addr_cnt > 0) {
632 			errmsg = "unexpected address";
633 			return ERR;
634 		}
635 		GET_COMMAND_SUFFIX();
636 		gflag =  (modified && !scripted && c == 'q') ? EMOD : EOF;
637 		break;
638 	case 'r':
639 		if (!isspace((unsigned char)*ibufp)) {
640 			errmsg = "unexpected command suffix";
641 			return ERR;
642 		} else if (addr_cnt == 0)
643 			second_addr = addr_last;
644 		if ((fnp = get_filename()) == NULL)
645 			return ERR;
646 		GET_COMMAND_SUFFIX();
647 		if (!isglobal) clear_undo_stack();
648 		if (*old_filename == '\0' && *fnp != '!')
649 			strlcpy(old_filename, fnp, PATH_MAX);
650 #ifdef BACKWARDS
651 		if (*fnp == '\0' && *old_filename == '\0') {
652 			errmsg = "no current filename";
653 			return ERR;
654 		}
655 #endif
656 		if ((addr = read_file(*fnp ? fnp : old_filename, second_addr)) < 0)
657 			return ERR;
658 		else if (addr && addr != addr_last)
659 			modified = 1;
660 		break;
661 	case 's':
662 		do {
663 			switch(*ibufp) {
664 			case '\n':
665 				sflags |=SGF;
666 				break;
667 			case 'g':
668 				sflags |= SGG;
669 				ibufp++;
670 				break;
671 			case 'p':
672 				sflags |= SGP;
673 				ibufp++;
674 				break;
675 			case 'r':
676 				sflags |= SGR;
677 				ibufp++;
678 				break;
679 			case '0': case '1': case '2': case '3': case '4':
680 			case '5': case '6': case '7': case '8': case '9':
681 				STRTOL(sgnum, ibufp);
682 				sflags |= SGF;
683 				sgflag &= ~GSG;		/* override GSG */
684 				break;
685 			default:
686 				if (sflags) {
687 					errmsg = "invalid command suffix";
688 					return ERR;
689 				}
690 			}
691 		} while (sflags && *ibufp != '\n');
692 		if (sflags && !pat) {
693 			errmsg = "no previous substitution";
694 			return ERR;
695 		} else if (sflags & SGG)
696 			sgnum = 0;		/* override numeric arg */
697 		if (*ibufp != '\n' && *(ibufp + 1) == '\n') {
698 			errmsg = "invalid pattern delimiter";
699 			return ERR;
700 		}
701 		tpat = pat;
702 		SPL1();
703 		if ((!sflags || (sflags & SGR)) &&
704 		    (tpat = get_compiled_pattern()) == NULL) {
705 		 	SPL0();
706 			return ERR;
707 		} else if (tpat != pat) {
708 			if (pat) {
709 				regfree(pat);
710 				free(pat);
711 			}
712 			pat = tpat;
713 			patlock = 1;		/* reserve pattern */
714 		}
715 		SPL0();
716 		if (!sflags && extract_subst_tail(&sgflag, &sgnum) < 0)
717 			return ERR;
718 		else if (isglobal)
719 			sgflag |= GLB;
720 		else
721 			sgflag &= ~GLB;
722 		if (sflags & SGG)
723 			sgflag ^= GSG;
724 		if (sflags & SGP)
725 			sgflag ^= GPR, sgflag &= ~(GLS | GNP);
726 		do {
727 			switch(*ibufp) {
728 			case 'p':
729 				sgflag |= GPR, ibufp++;
730 				break;
731 			case 'l':
732 				sgflag |= GLS, ibufp++;
733 				break;
734 			case 'n':
735 				sgflag |= GNP, ibufp++;
736 				break;
737 			default:
738 				n++;
739 			}
740 		} while (!n);
741 		if (check_addr_range(current_addr, current_addr) < 0)
742 			return ERR;
743 		GET_COMMAND_SUFFIX();
744 		if (!isglobal) clear_undo_stack();
745 		if (search_and_replace(pat, sgflag, sgnum) < 0)
746 			return ERR;
747 		break;
748 	case 't':
749 		if (check_addr_range(current_addr, current_addr) < 0)
750 			return ERR;
751 		GET_THIRD_ADDR(addr);
752 		GET_COMMAND_SUFFIX();
753 		if (!isglobal) clear_undo_stack();
754 		if (copy_lines(addr) < 0)
755 			return ERR;
756 		break;
757 	case 'u':
758 		if (addr_cnt > 0) {
759 			errmsg = "unexpected address";
760 			return ERR;
761 		}
762 		GET_COMMAND_SUFFIX();
763 		if (pop_undo_stack() < 0)
764 			return ERR;
765 		break;
766 	case 'w':
767 	case 'W':
768 		if ((n = *ibufp) == 'q' || n == 'Q') {
769 			gflag = EOF;
770 			ibufp++;
771 		}
772 		if (!isspace((unsigned char)*ibufp)) {
773 			errmsg = "unexpected command suffix";
774 			return ERR;
775 		} else if ((fnp = get_filename()) == NULL)
776 			return ERR;
777 		if (addr_cnt == 0 && !addr_last)
778 			first_addr = second_addr = 0;
779 		else if (check_addr_range(1, addr_last) < 0)
780 			return ERR;
781 		GET_COMMAND_SUFFIX();
782 		if (*old_filename == '\0' && *fnp != '!')
783 			strlcpy(old_filename, fnp, PATH_MAX);
784 #ifdef BACKWARDS
785 		if (*fnp == '\0' && *old_filename == '\0') {
786 			errmsg = "no current filename";
787 			return ERR;
788 		}
789 #endif
790 		if ((addr = write_file(*fnp ? fnp : old_filename,
791 		    (c == 'W') ? "a" : "w", first_addr, second_addr)) < 0)
792 			return ERR;
793 		else if (addr == addr_last && *fnp != '!')
794 			modified = 0;
795 		else if (modified && !scripted && n == 'q')
796 			gflag = EMOD;
797 		break;
798 	case 'x':
799 		if (addr_cnt > 0) {
800 			errmsg = "unexpected address";
801 			return ERR;
802 		}
803 		GET_COMMAND_SUFFIX();
804 		errmsg = "crypt unavailable";
805 		return ERR;
806 	case 'z':
807 #ifdef BACKWARDS
808 		if (check_addr_range(first_addr = 1, current_addr + 1) < 0)
809 #else
810 		if (check_addr_range(first_addr = 1, current_addr + !isglobal) < 0)
811 #endif
812 			return ERR;
813 		else if ('0' < *ibufp && *ibufp <= '9')
814 			STRTOL(rows, ibufp);
815 		GET_COMMAND_SUFFIX();
816 		if (display_lines(second_addr, min(addr_last,
817 		    second_addr + rows), gflag) < 0)
818 			return ERR;
819 		gflag = 0;
820 		break;
821 	case '=':
822 		GET_COMMAND_SUFFIX();
823 		printf("%ld\n", addr_cnt ? second_addr : addr_last);
824 		break;
825 	case '!':
826 		if (addr_cnt > 0) {
827 			errmsg = "unexpected address";
828 			return ERR;
829 		} else if ((sflags = get_shell_command()) < 0)
830 			return ERR;
831 		GET_COMMAND_SUFFIX();
832 		if (sflags) printf("%s\n", shcmd + 1);
833 		system(shcmd + 1);
834 		if (!scripted) printf("!\n");
835 		break;
836 	case '\n':
837 #ifdef BACKWARDS
838 		if (check_addr_range(first_addr = 1, current_addr + 1) < 0
839 #else
840 		if (check_addr_range(first_addr = 1, current_addr + !isglobal) < 0
841 #endif
842 		 || display_lines(second_addr, second_addr, 0) < 0)
843 			return ERR;
844 		break;
845 	default:
846 		errmsg = "unknown command";
847 		return ERR;
848 	}
849 	return gflag;
850 }
851 
852 
853 /* check_addr_range: return status of address range check */
854 int
855 check_addr_range(long n, long m)
856 {
857 	if (addr_cnt == 0) {
858 		first_addr = n;
859 		second_addr = m;
860 	}
861 	if (first_addr > second_addr || 1 > first_addr ||
862 	    second_addr > addr_last) {
863 		errmsg = "invalid address";
864 		return ERR;
865 	}
866 	return 0;
867 }
868 
869 
870 /* get_matching_node_addr: return the address of the next line matching a
871    pattern in a given direction.  wrap around begin/end of editor buffer if
872    necessary */
873 long
874 get_matching_node_addr(pattern_t *pat, int dir)
875 {
876 	char *s;
877 	long n = current_addr;
878 	line_t *lp;
879 
880 	if (!pat) return ERR;
881 	do {
882 	       if ((n = dir ? INC_MOD(n, addr_last) : DEC_MOD(n, addr_last))) {
883 			lp = get_addressed_line_node(n);
884 			if ((s = get_sbuf_line(lp)) == NULL)
885 				return ERR;
886 			if (isbinary)
887 				NUL_TO_NEWLINE(s, lp->len);
888 			if (!regexec(pat, s, 0, NULL, 0))
889 				return n;
890 	       }
891 	} while (n != current_addr);
892 	errmsg = "no match";
893 	return  ERR;
894 }
895 
896 
897 /* get_filename: return pointer to copy of filename in the command buffer */
898 char *
899 get_filename(void)
900 {
901 	static char *file = NULL;
902 	static int filesz = 0;
903 
904 	int n;
905 
906 	if (*ibufp != '\n') {
907 		SKIP_BLANKS();
908 		if (*ibufp == '\n') {
909 			errmsg = "invalid filename";
910 			return NULL;
911 		} else if ((ibufp = get_extended_line(&n, 1)) == NULL)
912 			return NULL;
913 		else if (*ibufp == '!') {
914 			ibufp++;
915 			if ((n = get_shell_command()) < 0)
916 				return NULL;
917 			if (n)
918 				printf("%s\n", shcmd + 1);
919 			return shcmd;
920 		} else if (n > PATH_MAX - 1) {
921 			errmsg = "filename too long";
922 			return  NULL;
923 		}
924 	}
925 #ifndef BACKWARDS
926 	else if (*old_filename == '\0') {
927 		errmsg = "no current filename";
928 		return  NULL;
929 	}
930 #endif
931 	REALLOC(file, filesz, PATH_MAX, NULL);
932 	for (n = 0; *ibufp != '\n';)
933 		file[n++] = *ibufp++;
934 	file[n] = '\0';
935 	return is_legal_filename(file) ? file : NULL;
936 }
937 
938 
939 /* get_shell_command: read a shell command from stdin; return substitution
940    status */
941 int
942 get_shell_command(void)
943 {
944 	static char *buf = NULL;
945 	static int n = 0;
946 
947 	char *s;			/* substitution char pointer */
948 	int i = 0;
949 	int j = 0;
950 
951 	if (red) {
952 		errmsg = "shell access restricted";
953 		return ERR;
954 	} else if ((s = ibufp = get_extended_line(&j, 1)) == NULL)
955 		return ERR;
956 	REALLOC(buf, n, j + 1, ERR);
957 	buf[i++] = '!';			/* prefix command w/ bang */
958 	while (*ibufp != '\n')
959 		switch (*ibufp) {
960 		default:
961 			REALLOC(buf, n, i + 2, ERR);
962 			buf[i++] = *ibufp;
963 			if (*ibufp++ == '\\')
964 				buf[i++] = *ibufp++;
965 			break;
966 		case '!':
967 			if (s != ibufp) {
968 				REALLOC(buf, n, i + 1, ERR);
969 				buf[i++] = *ibufp++;
970 			}
971 #ifdef BACKWARDS
972 			else if (shcmd == NULL || *(shcmd + 1) == '\0')
973 #else
974 			else if (shcmd == NULL)
975 #endif
976 			{
977 				errmsg = "no previous command";
978 				return ERR;
979 			} else {
980 				REALLOC(buf, n, i + shcmdi, ERR);
981 				for (s = shcmd + 1; s < shcmd + shcmdi;)
982 					buf[i++] = *s++;
983 				s = ibufp++;
984 			}
985 			break;
986 		case '%':
987 			if (*old_filename  == '\0') {
988 				errmsg = "no current filename";
989 				return ERR;
990 			}
991 			j = strlen(s = strip_escapes(old_filename));
992 			REALLOC(buf, n, i + j, ERR);
993 			while (j--)
994 				buf[i++] = *s++;
995 			s = ibufp++;
996 			break;
997 		}
998 	REALLOC(shcmd, shcmdsz, i + 1, ERR);
999 	memcpy(shcmd, buf, i);
1000 	shcmd[shcmdi = i] = '\0';
1001 	return *s == '!' || *s == '%';
1002 }
1003 
1004 
1005 /* append_lines: insert text from stdin to after line n; stop when either a
1006    single period is read or EOF; return status */
1007 int
1008 append_lines(long n)
1009 {
1010 	int l;
1011 	const char *lp = ibuf;
1012 	const char *eot;
1013 	undo_t *up = NULL;
1014 
1015 	for (current_addr = n;;) {
1016 		if (!isglobal) {
1017 			if ((l = get_tty_line()) < 0)
1018 				return ERR;
1019 			else if (l == 0 || ibuf[l - 1] != '\n') {
1020 				clearerr(stdin);
1021 				return  l ? EOF : 0;
1022 			}
1023 			lp = ibuf;
1024 		} else if (*(lp = ibufp) == '\0')
1025 			return 0;
1026 		else {
1027 			while (*ibufp++ != '\n')
1028 				;
1029 			l = ibufp - lp;
1030 		}
1031 		if (l == 2 && lp[0] == '.' && lp[1] == '\n') {
1032 			return 0;
1033 		}
1034 		eot = lp + l;
1035 		SPL1();
1036 		do {
1037 			if ((lp = put_sbuf_line(lp)) == NULL) {
1038 				SPL0();
1039 				return ERR;
1040 			} else if (up)
1041 				up->t = get_addressed_line_node(current_addr);
1042 			else if ((up = push_undo_stack(UADD, current_addr,
1043 			    current_addr)) == NULL) {
1044 				SPL0();
1045 				return ERR;
1046 			}
1047 		} while (lp != eot);
1048 		modified = 1;
1049 		SPL0();
1050 	}
1051 	/* NOTREACHED */
1052 }
1053 
1054 
1055 /* join_lines: replace a range of lines with the joined text of those lines */
1056 int
1057 join_lines(long from, long to)
1058 {
1059 	static char *buf = NULL;
1060 	static int n;
1061 
1062 	char *s;
1063 	int size = 0;
1064 	line_t *bp, *ep;
1065 
1066 	ep = get_addressed_line_node(INC_MOD(to, addr_last));
1067 	bp = get_addressed_line_node(from);
1068 	for (; bp != ep; bp = bp->q_forw) {
1069 		if ((s = get_sbuf_line(bp)) == NULL)
1070 			return ERR;
1071 		REALLOC(buf, n, size + bp->len, ERR);
1072 		memcpy(buf + size, s, bp->len);
1073 		size += bp->len;
1074 	}
1075 	REALLOC(buf, n, size + 2, ERR);
1076 	memcpy(buf + size, "\n", 2);
1077 	if (delete_lines(from, to) < 0)
1078 		return ERR;
1079 	current_addr = from - 1;
1080 	SPL1();
1081 	if (put_sbuf_line(buf) == NULL ||
1082 	    push_undo_stack(UADD, current_addr, current_addr) == NULL) {
1083 		SPL0();
1084 		return ERR;
1085 	}
1086 	modified = 1;
1087 	SPL0();
1088 	return 0;
1089 }
1090 
1091 
1092 /* move_lines: move a range of lines */
1093 int
1094 move_lines(long addr)
1095 {
1096 	line_t *b1, *a1, *b2, *a2;
1097 	long n = INC_MOD(second_addr, addr_last);
1098 	long p = first_addr - 1;
1099 	int done = (addr == first_addr - 1 || addr == second_addr);
1100 
1101 	SPL1();
1102 	if (done) {
1103 		a2 = get_addressed_line_node(n);
1104 		b2 = get_addressed_line_node(p);
1105 		current_addr = second_addr;
1106 	} else if (push_undo_stack(UMOV, p, n) == NULL ||
1107 	    push_undo_stack(UMOV, addr, INC_MOD(addr, addr_last)) == NULL) {
1108 		SPL0();
1109 		return ERR;
1110 	} else {
1111 		a1 = get_addressed_line_node(n);
1112 		if (addr < first_addr) {
1113 			b1 = get_addressed_line_node(p);
1114 			b2 = get_addressed_line_node(addr);
1115 					/* this get_addressed_line_node last! */
1116 		} else {
1117 			b2 = get_addressed_line_node(addr);
1118 			b1 = get_addressed_line_node(p);
1119 					/* this get_addressed_line_node last! */
1120 		}
1121 		a2 = b2->q_forw;
1122 		REQUE(b2, b1->q_forw);
1123 		REQUE(a1->q_back, a2);
1124 		REQUE(b1, a1);
1125 		current_addr = addr + ((addr < first_addr) ?
1126 		    second_addr - first_addr + 1 : 0);
1127 	}
1128 	if (isglobal)
1129 		unset_active_nodes(b2->q_forw, a2);
1130 	modified = 1;
1131 	SPL0();
1132 	return 0;
1133 }
1134 
1135 
1136 /* copy_lines: copy a range of lines; return status */
1137 int
1138 copy_lines(long addr)
1139 {
1140 	line_t *lp, *np = get_addressed_line_node(first_addr);
1141 	undo_t *up = NULL;
1142 	long n = second_addr - first_addr + 1;
1143 	long m = 0;
1144 
1145 	current_addr = addr;
1146 	if (first_addr <= addr && addr < second_addr) {
1147 		n =  addr - first_addr + 1;
1148 		m = second_addr - addr;
1149 	}
1150 	for (; n > 0; n=m, m=0, np = get_addressed_line_node(current_addr + 1))
1151 		for (; n-- > 0; np = np->q_forw) {
1152 			SPL1();
1153 			if ((lp = dup_line_node(np)) == NULL) {
1154 				SPL0();
1155 				return ERR;
1156 			}
1157 			add_line_node(lp);
1158 			if (up)
1159 				up->t = lp;
1160 			else if ((up = push_undo_stack(UADD, current_addr,
1161 			    current_addr)) == NULL) {
1162 				SPL0();
1163 				return ERR;
1164 			}
1165 			modified = 1;
1166 			SPL0();
1167 		}
1168 	return 0;
1169 }
1170 
1171 
1172 /* delete_lines: delete a range of lines */
1173 int
1174 delete_lines(long from, long to)
1175 {
1176 	line_t *n, *p;
1177 
1178 	SPL1();
1179 	if (push_undo_stack(UDEL, from, to) == NULL) {
1180 		SPL0();
1181 		return ERR;
1182 	}
1183 	n = get_addressed_line_node(INC_MOD(to, addr_last));
1184 	p = get_addressed_line_node(from - 1);
1185 					/* this get_addressed_line_node last! */
1186 	if (isglobal)
1187 		unset_active_nodes(p->q_forw, n);
1188 	REQUE(p, n);
1189 	addr_last -= to - from + 1;
1190 	current_addr = from - 1;
1191 	modified = 1;
1192 	SPL0();
1193 	return 0;
1194 }
1195 
1196 
1197 /* display_lines: print a range of lines to stdout */
1198 int
1199 display_lines(long from, long to, int gflag)
1200 {
1201 	line_t *bp;
1202 	line_t *ep;
1203 	char *s;
1204 
1205 	if (!from) {
1206 		errmsg = "invalid address";
1207 		return ERR;
1208 	}
1209 	ep = get_addressed_line_node(INC_MOD(to, addr_last));
1210 	bp = get_addressed_line_node(from);
1211 	for (; bp != ep; bp = bp->q_forw) {
1212 		if ((s = get_sbuf_line(bp)) == NULL)
1213 			return ERR;
1214 		if (put_tty_line(s, bp->len, current_addr = from++, gflag) < 0)
1215 			return ERR;
1216 	}
1217 	return 0;
1218 }
1219 
1220 
1221 #define MAXMARK 26			/* max number of marks */
1222 
1223 static line_t *mark[MAXMARK];		/* line markers */
1224 static int markno;			/* line marker count */
1225 
1226 /* mark_line_node: set a line node mark */
1227 int
1228 mark_line_node(line_t *lp, int n)
1229 {
1230 	if (!islower((unsigned char)n)) {
1231 		errmsg = "invalid mark character";
1232 		return ERR;
1233 	} else if (mark[n - 'a'] == NULL)
1234 		markno++;
1235 	mark[n - 'a'] = lp;
1236 	return 0;
1237 }
1238 
1239 
1240 /* get_marked_node_addr: return address of a marked line */
1241 long
1242 get_marked_node_addr(int n)
1243 {
1244 	if (!islower((unsigned char)n)) {
1245 		errmsg = "invalid mark character";
1246 		return ERR;
1247 	}
1248 	return get_line_node_addr(mark[n - 'a']);
1249 }
1250 
1251 
1252 /* unmark_line_node: clear line node mark */
1253 void
1254 unmark_line_node(line_t *lp)
1255 {
1256 	int i;
1257 
1258 	for (i = 0; markno && i < MAXMARK; i++)
1259 		if (mark[i] == lp) {
1260 			mark[i] = NULL;
1261 			markno--;
1262 		}
1263 }
1264 
1265 
1266 /* dup_line_node: return a pointer to a copy of a line node */
1267 line_t *
1268 dup_line_node(line_t *lp)
1269 {
1270 	line_t *np;
1271 
1272 	if ((np = (line_t *) malloc(sizeof(line_t))) == NULL) {
1273 		fprintf(stderr, "%s\n", strerror(errno));
1274 		errmsg = "out of memory";
1275 		return NULL;
1276 	}
1277 	np->seek = lp->seek;
1278 	np->len = lp->len;
1279 	return np;
1280 }
1281 
1282 
1283 /* has_trailing_escape:  return the parity of escapes preceding a character
1284    in a string */
1285 int
1286 has_trailing_escape(char *s, char *t)
1287 {
1288     return (s == t || *(t - 1) != '\\') ? 0 : !has_trailing_escape(s, t - 1);
1289 }
1290 
1291 
1292 /* strip_escapes: return a copy of escaped string of at most length PATH_MAX */
1293 char *
1294 strip_escapes(char *s)
1295 {
1296 	static char *file = NULL;
1297 	static int filesz = 0;
1298 
1299 	int i = 0;
1300 
1301 	REALLOC(file, filesz, PATH_MAX, NULL);
1302 	while (i < filesz - 1	/* Worry about a possible trailing escape */
1303 	       && (file[i++] = (*s == '\\') ? *++s : *s))
1304 		s++;
1305 	return file;
1306 }
1307 
1308 
1309 void
1310 signal_hup(int signo)
1311 {
1312 	if (mutex)
1313 		sigflags |= (1 << (signo - 1));
1314 	else
1315 		handle_hup(signo);
1316 }
1317 
1318 
1319 void
1320 signal_int(int signo)
1321 {
1322 	if (mutex)
1323 		sigflags |= (1 << (signo - 1));
1324 	else
1325 		handle_int(signo);
1326 }
1327 
1328 
1329 void
1330 handle_hup(int signo)
1331 {
1332 	char *hup = NULL;		/* hup filename */
1333 	char *s;
1334 	char ed_hup[] = "ed.hup";
1335 	size_t n;
1336 
1337 	if (!sigactive)
1338 		quit(1);
1339 	sigflags &= ~(1 << (signo - 1));
1340 	if (addr_last && write_file(ed_hup, "w", 1, addr_last) < 0 &&
1341 	    (s = getenv("HOME")) != NULL &&
1342 	    (n = strlen(s)) + 8 <= PATH_MAX &&	/* "ed.hup" + '/' */
1343 	    (hup = (char *) malloc(n + 10)) != NULL) {
1344 		strcpy(hup, s);
1345 		if (hup[n - 1] != '/')
1346 			hup[n] = '/', hup[n+1] = '\0';
1347 		strcat(hup, "ed.hup");
1348 		write_file(hup, "w", 1, addr_last);
1349 	}
1350 	quit(2);
1351 }
1352 
1353 
1354 void
1355 handle_int(int signo)
1356 {
1357 	if (!sigactive)
1358 		quit(1);
1359 	sigflags &= ~(1 << (signo - 1));
1360 #ifdef _POSIX_SOURCE
1361 	siglongjmp(env, -1);
1362 #else
1363 	longjmp(env, -1);
1364 #endif
1365 }
1366 
1367 
1368 int cols = 72;				/* wrap column */
1369 
1370 void
1371 handle_winch(int signo)
1372 {
1373 	int save_errno = errno;
1374 
1375 	struct winsize ws;		/* window size structure */
1376 
1377 	sigflags &= ~(1 << (signo - 1));
1378 	if (ioctl(0, TIOCGWINSZ, (char *) &ws) >= 0) {
1379 		if (ws.ws_row > 2) rows = ws.ws_row - 2;
1380 		if (ws.ws_col > 8) cols = ws.ws_col - 8;
1381 	}
1382 	errno = save_errno;
1383 }
1384 
1385 
1386 /* is_legal_filename: return a legal filename */
1387 int
1388 is_legal_filename(char *s)
1389 {
1390 	if (red && (*s == '!' || !strcmp(s, "..") || strchr(s, '/'))) {
1391 		errmsg = "shell access restricted";
1392 		return 0;
1393 	}
1394 	return 1;
1395 }
1396