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1 /* main.c: This file contains the main control and user-interface routines
2    for the ed line editor. */
3 /*-
4  * Copyright (c) 1993 Andrew Moore, Talke Studio.
5  * All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  *
16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26  * SUCH DAMAGE.
27  */
28
29 #ifndef lint
30 #if 0
31 static const char copyright[] =
32 "@(#) Copyright (c) 1993 Andrew Moore, Talke Studio. \n\
33  All rights reserved.\n";
34 #endif
35 #endif /* not lint */
36
37 #include <sys/cdefs.h>
38 __FBSDID("$FreeBSD$");
39
40 /*
41  * CREDITS
42  *
43  *      This program is based on the editor algorithm described in
44  *      Brian W. Kernighan and P. J. Plauger's book "Software Tools
45  *      in Pascal," Addison-Wesley, 1981.
46  *
47  *      The buffering algorithm is attributed to Rodney Ruddock of
48  *      the University of Guelph, Guelph, Ontario.
49  *
50  *      The cbc.c encryption code is adapted from
51  *      the bdes program by Matt Bishop of Dartmouth College,
52  *      Hanover, NH.
53  *
54  */
55
56 #include <sys/types.h>
57
58 #include <sys/ioctl.h>
59 #include <sys/wait.h>
60 #include <ctype.h>
61 #include <locale.h>
62 #include <pwd.h>
63 #include <setjmp.h>
64
65 #include "ed.h"
66
67
68 #ifdef _POSIX_SOURCE
69 static sigjmp_buf env;
70 #else
71 static jmp_buf env;
72 #endif
73
74 /* static buffers */
75 char stdinbuf[1];               /* stdin buffer */
76 static char *shcmd;             /* shell command buffer */
77 static int shcmdsz;             /* shell command buffer size */
78 static int shcmdi;              /* shell command buffer index */
79 char *ibuf;                     /* ed command-line buffer */
80 int ibufsz;                     /* ed command-line buffer size */
81 char *ibufp;                    /* pointer to ed command-line buffer */
82
83 /* global flags */
84 int des = 0;                    /* if set, use crypt(3) for i/o */
85 static int garrulous = 0;       /* if set, print all error messages */
86 int isbinary;                   /* if set, buffer contains ASCII NULs */
87 int isglobal;                   /* if set, doing a global command */
88 int modified;                   /* if set, buffer modified since last write */
89 int mutex = 0;                  /* if set, signals set "sigflags" */
90 static int red = 0;             /* if set, restrict shell/directory access */
91 int scripted = 0;               /* if set, suppress diagnostics */
92 int sigflags = 0;               /* if set, signals received while mutex set */
93 static int sigactive = 0;       /* if set, signal handlers are enabled */
94
95 static char old_filename[PATH_MAX] = ""; /* default filename */
96 long current_addr;              /* current address in editor buffer */
97 long addr_last;                 /* last address in editor buffer */
98 int lineno;                     /* script line number */
99 static const char *prompt;      /* command-line prompt */
100 static const char *dps = "*";   /* default command-line prompt */
101
102 static const char *usage = "usage: %s [-] [-sx] [-p string] [file]\n";
103
104 /* ed: line editor */
105 int
106 main(volatile int argc, char ** volatile argv)
107 {
108         int c, n;
109         long status = 0;
110
111         (void)setlocale(LC_ALL, "");
112
113         red = (n = strlen(argv[0])) > 2 && argv[0][n - 3] == 'r';
114 top:
115         while ((c = getopt(argc, argv, "p:sx")) != -1)
116                 switch(c) {
117                 case 'p':                               /* set prompt */
118                         prompt = optarg;
119                         break;
120                 case 's':                               /* run script */
121                         scripted = 1;
122                         break;
123                 case 'x':                               /* use crypt */
124 #ifdef DES
125                         des = get_keyword();
126 #else
127                         fprintf(stderr, "crypt unavailable\n?\n");
128 #endif
129                         break;
130
131                 default:
132                         fprintf(stderr, usage, red ? "red" : "ed");
133                         exit(1);
134                 }
135         argv += optind;
136         argc -= optind;
137         if (argc && **argv == '-') {
138                 scripted = 1;
139                 if (argc > 1) {
140                         optind = 1;
141                         goto top;
142                 }
143                 argv++;
144                 argc--;
145         }
146         /* assert: reliable signals! */
147 #ifdef SIGWINCH
148         handle_winch(SIGWINCH);
149         if (isatty(0)) signal(SIGWINCH, handle_winch);
150 #endif
151         signal(SIGHUP, signal_hup);
152         signal(SIGQUIT, SIG_IGN);
153         signal(SIGINT, signal_int);
154 #ifdef _POSIX_SOURCE
155         if ((status = sigsetjmp(env, 1)))
156 #else
157         if ((status = setjmp(env)))
158 #endif
159         {
160                 fputs("\n?\n", stderr);
161                 errmsg = "interrupt";
162         } else {
163                 init_buffers();
164                 sigactive = 1;                  /* enable signal handlers */
165                 if (argc && **argv && is_legal_filename(*argv)) {
166                         if (read_file(*argv, 0) < 0 && !isatty(0))
167                                 quit(2);
168                         else if (**argv != '!')
169                                 if (strlcpy(old_filename, *argv, sizeof(old_filename))
170                                     >= sizeof(old_filename))
171                                         quit(2);
172                 } else if (argc) {
173                         fputs("?\n", stderr);
174                         if (**argv == '\0')
175                                 errmsg = "invalid filename";
176                         if (!isatty(0))
177                                 quit(2);
178                 }
179         }
180         for (;;) {
181                 if (status < 0 && garrulous)
182                         fprintf(stderr, "%s\n", errmsg);
183                 if (prompt) {
184                         printf("%s", prompt);
185                         fflush(stdout);
186                 }
187                 if ((n = get_tty_line()) < 0) {
188                         status = ERR;
189                         continue;
190                 } else if (n == 0) {
191                         if (modified && !scripted) {
192                                 fputs("?\n", stderr);
193                                 errmsg = "warning: file modified";
194                                 if (!isatty(0)) {
195                                         if (garrulous)
196                                                 fprintf(stderr,
197                                                     "script, line %d: %s\n",
198                                                     lineno, errmsg);
199                                         quit(2);
200                                 }
201                                 clearerr(stdin);
202                                 modified = 0;
203                                 status = EMOD;
204                                 continue;
205                         } else
206                                 quit(0);
207                 } else if (ibuf[n - 1] != '\n') {
208                         /* discard line */
209                         errmsg = "unexpected end-of-file";
210                         clearerr(stdin);
211                         status = ERR;
212                         continue;
213                 }
214                 isglobal = 0;
215                 if ((status = extract_addr_range()) >= 0 &&
216                     (status = exec_command()) >= 0)
217                         if (!status ||
218                             (status = display_lines(current_addr, current_addr,
219                                 status)) >= 0)
220                                 continue;
221                 switch (status) {
222                 case EOF:
223                         quit(0);
224                 case EMOD:
225                         modified = 0;
226                         fputs("?\n", stderr);           /* give warning */
227                         errmsg = "warning: file modified";
228                         if (!isatty(0)) {
229                                 if (garrulous)
230                                         fprintf(stderr, "script, line %d: %s\n",
231                                             lineno, errmsg);
232                                 quit(2);
233                         }
234                         break;
235                 case FATAL:
236                         if (!isatty(0)) {
237                                 if (garrulous)
238                                         fprintf(stderr, "script, line %d: %s\n",
239                                             lineno, errmsg);
240                         } else if (garrulous)
241                                 fprintf(stderr, "%s\n", errmsg);
242                         quit(3);
243                 default:
244                         fputs("?\n", stderr);
245                         if (!isatty(0)) {
246                                 if (garrulous)
247                                         fprintf(stderr, "script, line %d: %s\n",
248                                             lineno, errmsg);
249                                 quit(2);
250                         }
251                         break;
252                 }
253         }
254         /*NOTREACHED*/
255 }
256
257 long first_addr, second_addr;
258 static long addr_cnt;
259
260 /* extract_addr_range: get line addresses from the command buffer until an
261    illegal address is seen; return status */
262 int
263 extract_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 */
294 long
295 next_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
440 int patlock = 0;        /* if set, pattern not freed by get_compiled_pattern() */
441
442 long rows = 22;         /* scroll length: ws_row - 2 */
443
444 /* exec_command: execute the next command in command buffer; return print
445    request, if any */
446 int
447 exec_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 */
879 int
880 check_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 */
898 long
899 get_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 */
923 char *
924 get_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 */
966 int
967 get_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 */
1032 int
1033 append_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 */
1081 int
1082 join_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 */
1118 int
1119 move_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 */
1162 int
1163 copy_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 */
1198 int
1199 delete_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 */
1223 int
1224 display_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
1248 static line_t *mark[MAXMARK];           /* line markers */
1249 static int markno;                      /* line marker count */
1250
1251 /* mark_line_node: set a line node mark */
1252 int
1253 mark_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 */
1266 long
1267 get_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 */
1278 void
1279 unmark_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 */
1292 line_t *
1293 dup_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 */
1310 int
1311 has_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 */
1318 char *
1319 strip_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
1334 void
1335 signal_hup(int signo)
1336 {
1337         if (mutex)
1338                 sigflags |= (1 << (signo - 1));
1339         else
1340                 handle_hup(signo);
1341 }
1342
1343
1344 void
1345 signal_int(int signo)
1346 {
1347         if (mutex)
1348                 sigflags |= (1 << (signo - 1));
1349         else
1350                 handle_int(signo);
1351 }
1352
1353
1354 void
1355 handle_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
1379 void
1380 handle_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
1393 int cols = 72;                          /* wrap column */
1394
1395 void
1396 handle_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 */
1412 int
1413 is_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 }