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
54static sigjmp_buf env;
55#else
56static jmp_buf env;
57#endif
58
59/* static buffers */
60char stdinbuf[1];		/* stdin buffer */
61static char *shcmd;		/* shell command buffer */
62static int shcmdsz;		/* shell command buffer size */
63static int shcmdi;		/* shell command buffer index */
64char *ibuf;			/* ed command-line buffer */
65int ibufsz;			/* ed command-line buffer size */
66char *ibufp;			/* pointer to ed command-line buffer */
67
68/* global flags */
69static int garrulous = 0;	/* if set, print all error messages */
70int isbinary;			/* if set, buffer contains ASCII NULs */
71int isglobal;			/* if set, doing a global command */
72int modified;			/* if set, buffer modified since last write */
73int mutex = 0;			/* if set, signals set "sigflags" */
74static int red = 0;		/* if set, restrict shell/directory access */
75int scripted = 0;		/* if set, suppress diagnostics */
76int sigflags = 0;		/* if set, signals received while mutex set */
77static int sigactive = 0;	/* if set, signal handlers are enabled */
78
79static char old_filename[PATH_MAX] = ""; /* default filename */
80long current_addr;		/* current address in editor buffer */
81long addr_last;			/* last address in editor buffer */
82int lineno;			/* script line number */
83static const char *prompt;	/* command-line prompt */
84static const char *dps = "*";	/* default command-line prompt */
85
86static const char *usage = "usage: %s [-] [-sx] [-p string] [file]\n";
87
88/* ed: line editor */
89int
90main(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';
98top:
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
237long first_addr, second_addr;
238static long addr_cnt;
239
240/* extract_addr_range: get line addresses from the command buffer until an
241   illegal address is seen; return status */
242int
243extract_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 */
274long
275next_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
420int patlock = 0;	/* if set, pattern not freed by get_compiled_pattern() */
421
422long rows = 22;		/* scroll length: ws_row - 2 */
423
424/* exec_command: execute the next command in command buffer; return print
425   request, if any */
426int
427exec_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 */
854int
855check_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 */
873long
874get_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 */
898char *
899get_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 */
941int
942get_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 */
1007int
1008append_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 */
1056int
1057join_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 */
1093int
1094move_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 */
1137int
1138copy_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 */
1173int
1174delete_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 */
1198int
1199display_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
1223static line_t *mark[MAXMARK];		/* line markers */
1224static int markno;			/* line marker count */
1225
1226/* mark_line_node: set a line node mark */
1227int
1228mark_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 */
1241long
1242get_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 */
1253void
1254unmark_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 */
1267line_t *
1268dup_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 */
1285int
1286has_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 */
1293char *
1294strip_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
1309void
1310signal_hup(int signo)
1311{
1312	if (mutex)
1313		sigflags |= (1 << (signo - 1));
1314	else
1315		handle_hup(signo);
1316}
1317
1318
1319void
1320signal_int(int signo)
1321{
1322	if (mutex)
1323		sigflags |= (1 << (signo - 1));
1324	else
1325		handle_int(signo);
1326}
1327
1328
1329void
1330handle_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
1354void
1355handle_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
1368int cols = 72;				/* wrap column */
1369
1370void
1371handle_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 */
1387int
1388is_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