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