bin/ed/main.c

   1 /*      $NetBSD: main.c,v 1.25 2011/08/21 08:40:31 christos Exp $       */
   2
   3 /* main.c: This file contains the main control and user-interface routines
   4    for the ed line editor. */
   5 /*-
   6  * Copyright (c) 1993 Andrew Moore, Talke Studio.
   7  * All rights reserved.
   8  *
   9  * Redistribution and use in source and binary forms, with or without
  10  * modification, are permitted provided that the following conditions
  11  * are met:
  12  * 1. Redistributions of source code must retain the above copyright
  13  *    notice, this list of conditions and the following disclaimer.
  14  * 2. Redistributions in binary form must reproduce the above copyright
  15  *    notice, this list of conditions and the following disclaimer in the
  16  *    documentation and/or other materials provided with the distribution.
  17  *
  18  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  19  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  20  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  21  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  22  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  23  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  24  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  25  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  26  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  27  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  28  * SUCH DAMAGE.
  29  */
  30
  31 #include <sys/cdefs.h>
  32 #ifndef lint
  33 __COPYRIGHT(
  34 "@(#) Copyright (c) 1993 Andrew Moore, Talke Studio.\
  35  All rights reserved.");
  36 #endif /* not lint */
  37
  38 #ifndef lint
  39 #if 0
  40 static char *rcsid = "@(#)main.c,v 1.1 1994/02/01 00:34:42 alm Exp";
  41 #else
  42 __RCSID("$NetBSD: main.c,v 1.25 2011/08/21 08:40:31 christos Exp $");
  43 #endif
  44 #endif /* not lint */
  45
  46 /*
  47  * CREDITS
  48  *
  49  *      This program is based on the editor algorithm described in
  50  *      Brian W. Kernighan and P. J. Plauger's book "Software Tools
  51  *      in Pascal," Addison-Wesley, 1981.
  52  *
  53  *      The buffering algorithm is attributed to Rodney Ruddock of
  54  *      the University of Guelph, Guelph, Ontario.
  55  *
  56  *      The cbc.c encryption code is adapted from
  57  *      the bdes program by Matt Bishop of Dartmouth College,
  58  *      Hanover, NH.
  59  *
  60  */
  61
  62 #include <sys/ioctl.h>
  63 #include <sys/wait.h>
  64 #include <termios.h>
  65 #include <ctype.h>
  66 #include <setjmp.h>
  67 #include <pwd.h>
  68
  69 #include "ed.h"
  70
  71
  72 #ifdef _POSIX_SOURCE
  73 sigjmp_buf env;
  74 #else
  75 jmp_buf env;
  76 #endif
  77
  78 /* static buffers */
  79 char stdinbuf[1];               /* stdin buffer */
  80 char *shcmd;                    /* shell command buffer */
  81 int shcmdsz;                    /* shell command buffer size */
  82 int shcmdi;                     /* shell command buffer index */
  83 char *ibuf;                     /* ed command-line buffer */
  84 int ibufsz;                     /* ed command-line buffer size */
  85 char *ibufp;                    /* pointer to ed command-line buffer */
  86
  87 /* global flags */
  88 int des = 0;                    /* if set, use crypt(3) for i/o */
  89 int garrulous = 0;              /* if set, print all error messages */
  90 int isbinary;                   /* if set, buffer contains ASCII NULs */
  91 int isglobal;                   /* if set, doing a global command */
  92 int modified;                   /* if set, buffer modified since last write */
  93 int mutex = 0;                  /* if set, signals set "sigflags" */
  94 int red = 0;                    /* if set, restrict shell/directory access */
  95 int ere = 0;                    /* if set, use extended regexes */
  96 int scripted = 0;               /* if set, suppress diagnostics */
  97 int sigflags = 0;               /* if set, signals received while mutex set */
  98 int sigactive = 0;              /* if set, signal handlers are enabled */
  99
 100 char old_filename[MAXPATHLEN + 1] = ""; /* default filename */
 101 long current_addr;              /* current address in editor buffer */
 102 long addr_last;                 /* last address in editor buffer */
 103 int lineno;                     /* script line number */
 104 const char *prompt;                     /* command-line prompt */
 105 const char *dps = "*";          /* default command-line prompt */
 106
 107
 108 static const char usage[] = "Usage: %s [-] [-sxE] [-p string] [name]\n";
 109
 110 /* ed: line editor */
 111 int
 112 main(int ac, char *av[])
 113 {
 114         int c, n;
 115         long status = 0;
 116         volatile int argc = ac;
 117         char ** volatile argv = av;
 118
 119         red = (n = strlen(argv[0])) > 2 && argv[0][n - 3] == 'r';
 120 top:
 121         while ((c = getopt(argc, argv, "p:sxE")) != -1)
 122                 switch(c) {
 123                 case 'p':                               /* set prompt */
 124                         prompt = optarg;
 125                         break;
 126                 case 's':                               /* run script */
 127                         scripted = 1;
 128                         break;
 129                 case 'x':                               /* use crypt */
 130 #ifdef DES
 131                         des = get_keyword();
 132 #else
 133                         fprintf(stderr, "crypt unavailable\n?\n");
 134 #endif
 135                         break;
 136
 137                 case 'E':
 138                         ere = REG_EXTENDED;
 139                         break;
 140                 default:
 141                         fprintf(stderr, usage, getprogname());
 142                         exit(1);
 143                         /* NOTREACHED */
 144                 }
 145         argv += optind;
 146         argc -= optind;
 147         if (argc && **argv == '-') {
 148                 scripted = 1;
 149                 if (argc > 1) {
 150                         optind = 1;
 151                         goto top;
 152                 }
 153                 argv++;
 154                 argc--;
 155         }
 156         /* assert: reliable signals! */
 157 #ifdef SIGWINCH
 158         handle_winch(SIGWINCH);
 159         if (isatty(0)) signal(SIGWINCH, handle_winch);
 160 #endif
 161         signal(SIGHUP, signal_hup);
 162         signal(SIGQUIT, SIG_IGN);
 163         signal(SIGINT, signal_int);
 164 #ifdef _POSIX_SOURCE
 165         if ((status = sigsetjmp(env, 1)) != 0)
 166 #else
 167         if ((status = setjmp(env)) != 0)
 168 #endif
 169         {
 170                 fputs("\n?\n", stderr);
 171                 sprintf(errmsg, "interrupt");
 172         } else {
 173                 init_buffers();
 174                 sigactive = 1;                  /* enable signal handlers */
 175                 if (argc && **argv && is_legal_filename(*argv)) {
 176                         if (read_file(*argv, 0) < 0 && !isatty(0))
 177                                 quit(2);
 178                         else if (**argv != '!')
 179                                 strlcpy(old_filename, *argv,
 180                                     sizeof(old_filename) - 2);
 181                 } else if (argc) {
 182                         fputs("?\n", stderr);
 183                         if (**argv == '\0')
 184                                 sprintf(errmsg, "invalid filename");
 185                         if (!isatty(0))
 186                                 quit(2);
 187                 }
 188         }
 189         for (;;) {
 190                 if (status < 0 && garrulous)
 191                         fprintf(stderr, "%s\n", errmsg);
 192                 if (prompt) {
 193                         printf("%s", prompt);
 194                         fflush(stdout);
 195                 }
 196                 if ((n = get_tty_line()) < 0) {
 197                         status = ERR;
 198                         continue;
 199                 } else if (n == 0) {
 200                         if (modified && !scripted) {
 201                                 fputs("?\n", stderr);
 202                                 sprintf(errmsg, "warning: file modified");
 203                                 if (!isatty(0)) {
 204                                         if (garrulous) {
 205                                                 fprintf(stderr,
 206                                                     "script, line %d: %s\n",
 207                                                     lineno, errmsg);
 208                                         }
 209                                         quit(2);
 210                                 }
 211                                 clearerr(stdin);
 212                                 modified = 0;
 213                                 status = EMOD;
 214                                 continue;
 215                         } else
 216                                 quit(0);
 217                 } else if (ibuf[n - 1] != '\n') {
 218                         /* discard line */
 219                         sprintf(errmsg, "unexpected end-of-file");
 220                         clearerr(stdin);
 221                         status = ERR;
 222                         continue;
 223                 }
 224                 isglobal = 0;
 225                 if ((status = extract_addr_range()) >= 0 &&
 226                     (status = exec_command()) >= 0)
 227                         if (!status || (status &&
 228                             (status = display_lines(current_addr, current_addr,
 229                                 status))) >= 0)
 230                                 continue;
 231                 switch (status) {
 232                 case EOF:
 233                         quit(0);
 234                 case EMOD:
 235                         modified = 0;
 236                         fputs("?\n", stderr);           /* give warning */
 237                         sprintf(errmsg, "warning: file modified");
 238                         if (!isatty(0)) {
 239                                 if (garrulous) {
 240                                         fprintf(stderr,
 241                                             "script, line %d: %s\n",
 242                                             lineno, errmsg);
 243                                 }
 244                                 quit(2);
 245                         }
 246                         break;
 247                 case FATAL:
 248                         if (garrulous) {
 249                                 if (!isatty(0)) {
 250                                         fprintf(stderr,
 251                                             "script, line %d: %s\n",
 252                                             lineno, errmsg);
 253                                 } else {
 254                                         fprintf(stderr, "%s\n", errmsg);
 255                                 }
 256                         }
 257                         quit(3);
 258                 default:
 259                         fputs("?\n", stderr);
 260                         if (!isatty(0)) {
 261                                 if (garrulous) {
 262                                         fprintf(stderr, "script, line %d: %s\n",
 263                                             lineno, errmsg);
 264                                 }
 265                                 quit(2);
 266                         }
 267                         break;
 268                 }
 269         }
 270         /* NOTREACHED */
 271 }
 272
 273 long first_addr, second_addr, addr_cnt;
 274
 275 /* extract_addr_range: get line addresses from the command buffer until an
 276    illegal address is seen; return status */
 277 int
 278 extract_addr_range(void)
 279 {
 280         long addr;
 281
 282         addr_cnt = 0;
 283         first_addr = second_addr = current_addr;
 284         while ((addr = next_addr()) >= 0) {
 285                 addr_cnt++;
 286                 first_addr = second_addr;
 287                 second_addr = addr;
 288                 if (*ibufp != ',' && *ibufp != ';')
 289                         break;
 290                 else if (*ibufp++ == ';')
 291                         current_addr = addr;
 292         }
 293         if ((addr_cnt = min(addr_cnt, 2)) == 1 || second_addr != addr)
 294                 first_addr = second_addr;
 295         return (addr == ERR) ? ERR : 0;
 296 }
 297
 298
 299 #define SKIP_BLANKS() while (isspace((unsigned char)*ibufp) && *ibufp != '\n') \
 300         ibufp++
 301
 302 #define MUST_BE_FIRST() \
 303         if (!first) { sprintf(errmsg, "invalid address"); return ERR; }
 304
 305 /*  next_addr: return the next line address in the command buffer */
 306 long
 307 next_addr(void)
 308 {
 309         char *hd;
 310         long addr = current_addr;
 311         long n;
 312         int first = 1;
 313         int c;
 314
 315         SKIP_BLANKS();
 316         for (hd = ibufp;; first = 0)
 317                 switch (c = *ibufp) {
 318                 case '+':
 319                 case '\t':
 320                 case ' ':
 321                 case '-':
 322                 case '^':
 323                         ibufp++;
 324                         SKIP_BLANKS();
 325                         if (isdigit((unsigned char)*ibufp)) {
 326                                 STRTOL(n, ibufp);
 327                                 addr += (c == '-' || c == '^') ? -n : n;
 328                         } else if (!isspace((unsigned char)c))
 329                                 addr += (c == '-' || c == '^') ? -1 : 1;
 330                         break;
 331                 case '0': case '1': case '2':
 332                 case '3': case '4': case '5':
 333                 case '6': case '7': case '8': case '9':
 334                         MUST_BE_FIRST();
 335                         STRTOL(addr, ibufp);
 336                         break;
 337                 case '.':
 338                 case '$':
 339                         MUST_BE_FIRST();
 340                         ibufp++;
 341                         addr = (c == '.') ? current_addr : addr_last;
 342                         break;
 343                 case '/':
 344                 case '?':
 345                         MUST_BE_FIRST();
 346                         if ((addr = get_matching_node_addr(
 347                             get_compiled_pattern(), c == '/')) < 0)
 348                                 return ERR;
 349                         else if (c == *ibufp)
 350                                 ibufp++;
 351                         break;
 352                 case '\'':
 353                         MUST_BE_FIRST();
 354                         ibufp++;
 355                         if ((addr = get_marked_node_addr((unsigned char)*ibufp++)) < 0)
 356                                 return ERR;
 357                         break;
 358                 case '%':
 359                 case ',':
 360                 case ';':
 361                         if (first) {
 362                                 ibufp++;
 363                                 addr_cnt++;
 364                                 second_addr = (c == ';') ? current_addr : 1;
 365                                 addr = addr_last;
 366                                 break;
 367                         }
 368                         /* FALL THROUGH */
 369                 default:
 370                         if (ibufp == hd)
 371                                 return EOF;
 372                         else if (addr < 0 || addr_last < addr) {
 373                                 sprintf(errmsg, "invalid address");
 374                                 return ERR;
 375                         } else
 376                                 return addr;
 377                 }
 378         /* NOTREACHED */
 379 }
 380
 381
 382 #ifdef BACKWARDS
 383 /* GET_THIRD_ADDR: get a legal address from the command buffer */
 384 #define GET_THIRD_ADDR(addr) \
 385 { \
 386         long ol1, ol2; \
 387 \
 388         ol1 = first_addr, ol2 = second_addr; \
 389         if (extract_addr_range() < 0) \
 390                 return ERR; \
 391         else if (addr_cnt == 0) { \
 392                 sprintf(errmsg, "destination expected"); \
 393                 return ERR; \
 394         } else if (second_addr < 0 || addr_last < second_addr) { \
 395                 sprintf(errmsg, "invalid address"); \
 396                 return ERR; \
 397         } \
 398         addr = second_addr; \
 399         first_addr = ol1, second_addr = ol2; \
 400 }
 401 #else   /* BACKWARDS */
 402 /* GET_THIRD_ADDR: get a legal address from the command buffer */
 403 #define GET_THIRD_ADDR(addr) \
 404 { \
 405         long ol1, ol2; \
 406 \
 407         ol1 = first_addr, ol2 = second_addr; \
 408         if (extract_addr_range() < 0) \
 409                 return ERR; \
 410         if (second_addr < 0 || addr_last < second_addr) { \
 411                 sprintf(errmsg, "invalid address"); \
 412                 return ERR; \
 413         } \
 414         addr = second_addr; \
 415         first_addr = ol1, second_addr = ol2; \
 416 }
 417 #endif
 418
 419
 420 /* GET_COMMAND_SUFFIX: verify the command suffix in the command buffer */
 421 #define GET_COMMAND_SUFFIX() { \
 422         int done = 0; \
 423         do { \
 424                 switch(*ibufp) { \
 425                 case 'p': \
 426                         gflag |= GPR, ibufp++; \
 427                         break; \
 428                 case 'l': \
 429                         gflag |= GLS, ibufp++; \
 430                         break; \
 431                 case 'n': \
 432                         gflag |= GNP, ibufp++; \
 433                         break; \
 434                 default: \
 435                         done++; \
 436                 } \
 437         } while (!done); \
 438         if (*ibufp++ != '\n') { \
 439                 sprintf(errmsg, "invalid command suffix"); \
 440                 return ERR; \
 441         } \
 442 }
 443
 444
 445 /* sflags */
 446 #define SGG 001         /* complement previous global substitute suffix */
 447 #define SGP 002         /* complement previous print suffix */
 448 #define SGR 004         /* use last regex instead of last pat */
 449 #define SGF 010         /* repeat last substitution */
 450
 451 int patlock = 0;        /* if set, pattern not freed by get_compiled_pattern() */
 452
 453 long rows = 22;         /* scroll length: ws_row - 2 */
 454
 455 /* exec_command: execute the next command in command buffer; return print
 456    request, if any */
 457 int
 458 exec_command(void)
 459 {
 460         static pattern_t *pat = NULL;
 461         static int sgflag = 0;
 462         static long sgnum = 0;
 463
 464         pattern_t *tpat;
 465         char *fnp;
 466         int gflag = 0;
 467         int sflags = 0;
 468         long addr = 0;
 469         int n = 0;
 470         int c;
 471
 472         SKIP_BLANKS();
 473         switch(c = *ibufp++) {
 474         case 'a':
 475                 GET_COMMAND_SUFFIX();
 476                 if (!isglobal) clear_undo_stack();
 477                 if (append_lines(second_addr) < 0)
 478                         return ERR;
 479                 break;
 480         case 'c':
 481                 if (check_addr_range(current_addr, current_addr) < 0)
 482                         return ERR;
 483                 GET_COMMAND_SUFFIX();
 484                 if (!isglobal) clear_undo_stack();
 485                 if (delete_lines(first_addr, second_addr) < 0 ||
 486                     append_lines(current_addr) < 0)
 487                         return ERR;
 488                 break;
 489         case 'd':
 490                 if (check_addr_range(current_addr, current_addr) < 0)
 491                         return ERR;
 492                 GET_COMMAND_SUFFIX();
 493                 if (!isglobal) clear_undo_stack();
 494                 if (delete_lines(first_addr, second_addr) < 0)
 495                         return ERR;
 496                 else if ((addr = INC_MOD(current_addr, addr_last)) != 0)
 497                         current_addr = addr;
 498                 break;
 499         case 'e':
 500                 if (modified && !scripted)
 501                         return EMOD;
 502                 /* fall through */
 503         case 'E':
 504                 if (addr_cnt > 0) {
 505                         sprintf(errmsg, "unexpected address");
 506                         return ERR;
 507                 } else if (!isspace((unsigned char)*ibufp)) {
 508                         sprintf(errmsg, "unexpected command suffix");
 509                         return ERR;
 510                 } else if ((fnp = get_filename()) == NULL)
 511                         return ERR;
 512                 GET_COMMAND_SUFFIX();
 513                 if (delete_lines(1, addr_last) < 0)
 514                         return ERR;
 515                 clear_undo_stack();
 516                 if (close_sbuf() < 0)
 517                         return ERR;
 518                 else if (open_sbuf() < 0)
 519                         return FATAL;
 520                 if (*fnp && *fnp != '!') strlcpy(old_filename, fnp,
 521                         sizeof(old_filename) - 2);
 522 #ifdef BACKWARDS
 523                 if (*fnp == '\0' && *old_filename == '\0') {
 524                         sprintf(errmsg, "no current filename");
 525                         return ERR;
 526                 }
 527 #endif
 528                 if (read_file(*fnp ? fnp : old_filename, 0) < 0)
 529                         return ERR;
 530                 clear_undo_stack();
 531                 modified = 0;
 532                 u_current_addr = u_addr_last = -1;
 533                 break;
 534         case 'f':
 535                 if (addr_cnt > 0) {
 536                         sprintf(errmsg, "unexpected address");
 537                         return ERR;
 538                 } else if (!isspace((unsigned char)*ibufp)) {
 539                         sprintf(errmsg, "unexpected command suffix");
 540                         return ERR;
 541                 } else if ((fnp = get_filename()) == NULL)
 542                         return ERR;
 543                 else if (*fnp == '!') {
 544                         sprintf(errmsg, "invalid redirection");
 545                         return ERR;
 546                 }
 547                 GET_COMMAND_SUFFIX();
 548                 if (*fnp) strlcpy(old_filename, fnp, sizeof(old_filename) - 2);
 549                 printf("%s\n", strip_escapes(old_filename));
 550                 break;
 551         case 'g':
 552         case 'v':
 553         case 'G':
 554         case 'V':
 555                 if (isglobal) {
 556                         sprintf(errmsg, "cannot nest global commands");
 557                         return ERR;
 558                 } else if (check_addr_range(1, addr_last) < 0)
 559                         return ERR;
 560                 else if (build_active_list(c == 'g' || c == 'G') < 0)
 561                         return ERR;
 562                 else if ((n = (c == 'G' || c == 'V')) != 0)
 563                         GET_COMMAND_SUFFIX();
 564                 isglobal++;
 565                 if (exec_global(n, gflag) < 0)
 566                         return ERR;
 567                 break;
 568         case 'h':
 569                 if (addr_cnt > 0) {
 570                         sprintf(errmsg, "unexpected address");
 571                         return ERR;
 572                 }
 573                 GET_COMMAND_SUFFIX();
 574                 if (*errmsg) fprintf(stderr, "%s\n", errmsg);
 575                 break;
 576         case 'H':
 577                 if (addr_cnt > 0) {
 578                         sprintf(errmsg, "unexpected address");
 579                         return ERR;
 580                 }
 581                 GET_COMMAND_SUFFIX();
 582                 if ((garrulous = 1 - garrulous) && *errmsg)
 583                         fprintf(stderr, "%s\n", errmsg);
 584                 break;
 585         case 'i':
 586                 if (second_addr == 0) {
 587                         sprintf(errmsg, "invalid address");
 588                         return ERR;
 589                 }
 590                 GET_COMMAND_SUFFIX();
 591                 if (!isglobal) clear_undo_stack();
 592                 if (append_lines(second_addr - 1) < 0)
 593                         return ERR;
 594                 break;
 595         case 'j':
 596                 if (check_addr_range(current_addr, current_addr + 1) < 0)
 597                         return ERR;
 598                 GET_COMMAND_SUFFIX();
 599                 if (!isglobal) clear_undo_stack();
 600                 if (first_addr != second_addr &&
 601                     join_lines(first_addr, second_addr) < 0)
 602                         return ERR;
 603                 break;
 604         case 'k':
 605                 c = *ibufp++;
 606                 if (second_addr == 0) {
 607                         sprintf(errmsg, "invalid address");
 608                         return ERR;
 609                 }
 610                 GET_COMMAND_SUFFIX();
 611                 if (mark_line_node(get_addressed_line_node(second_addr), (unsigned char)c) < 0)
 612                         return ERR;
 613                 break;
 614         case 'l':
 615                 if (check_addr_range(current_addr, current_addr) < 0)
 616                         return ERR;
 617                 GET_COMMAND_SUFFIX();
 618                 if (display_lines(first_addr, second_addr, gflag | GLS) < 0)
 619                         return ERR;
 620                 gflag = 0;
 621                 break;
 622         case 'm':
 623                 if (check_addr_range(current_addr, current_addr) < 0)
 624                         return ERR;
 625                 GET_THIRD_ADDR(addr);
 626                 if (first_addr <= addr && addr < second_addr) {
 627                         sprintf(errmsg, "invalid destination");
 628                         return ERR;
 629                 }
 630                 GET_COMMAND_SUFFIX();
 631                 if (!isglobal) clear_undo_stack();
 632                 if (move_lines(addr) < 0)
 633                         return ERR;
 634                 break;
 635         case 'n':
 636                 if (check_addr_range(current_addr, current_addr) < 0)
 637                         return ERR;
 638                 GET_COMMAND_SUFFIX();
 639                 if (display_lines(first_addr, second_addr, gflag | GNP) < 0)
 640                         return ERR;
 641                 gflag = 0;
 642                 break;
 643         case 'p':
 644                 if (check_addr_range(current_addr, current_addr) < 0)
 645                         return ERR;
 646                 GET_COMMAND_SUFFIX();
 647                 if (display_lines(first_addr, second_addr, gflag | GPR) < 0)
 648                         return ERR;
 649                 gflag = 0;
 650                 break;
 651         case 'P':
 652                 if (addr_cnt > 0) {
 653                         sprintf(errmsg, "unexpected address");
 654                         return ERR;
 655                 }
 656                 GET_COMMAND_SUFFIX();
 657                 prompt = prompt ? NULL : optarg ? optarg : dps;
 658                 break;
 659         case 'q':
 660         case 'Q':
 661                 if (addr_cnt > 0) {
 662                         sprintf(errmsg, "unexpected address");
 663                         return ERR;
 664                 }
 665                 GET_COMMAND_SUFFIX();
 666                 gflag =  (modified && !scripted && c == 'q') ? EMOD : EOF;
 667                 break;
 668         case 'r':
 669                 if (!isspace((unsigned char)*ibufp)) {
 670                         sprintf(errmsg, "unexpected command suffix");
 671                         return ERR;
 672                 } else if (addr_cnt == 0)
 673                         second_addr = addr_last;
 674                 if ((fnp = get_filename()) == NULL)
 675                         return ERR;
 676                 GET_COMMAND_SUFFIX();
 677                 if (!isglobal) clear_undo_stack();
 678                 if (*old_filename == '\0' && *fnp != '!')
 679                         strlcpy(old_filename, fnp, sizeof(old_filename) - 2);
 680 #ifdef BACKWARDS
 681                 if (*fnp == '\0' && *old_filename == '\0') {
 682                         sprintf(errmsg, "no current filename");
 683                         return ERR;
 684                 }
 685 #endif
 686                 if ((addr = read_file(*fnp ? fnp : old_filename, second_addr)) < 0)
 687                         return ERR;
 688                 else if (addr && addr != addr_last)
 689                         modified = 1;
 690                 break;
 691         case 's':
 692                 do {
 693                         switch(*ibufp) {
 694                         case '\n':
 695                                 sflags |=SGF;
 696                                 break;
 697                         case 'g':
 698                                 sflags |= SGG;
 699                                 ibufp++;
 700                                 break;
 701                         case 'p':
 702                                 sflags |= SGP;
 703                                 ibufp++;
 704                                 break;
 705                         case 'r':
 706                                 sflags |= SGR;
 707                                 ibufp++;
 708                                 break;
 709                         case '0': case '1': case '2': case '3': case '4':
 710                         case '5': case '6': case '7': case '8': case '9':
 711                                 STRTOL(sgnum, ibufp);
 712                                 sflags |= SGF;
 713                                 sgflag &= ~GSG;         /* override GSG */
 714                                 break;
 715                         default:
 716                                 if (sflags) {
 717                                         sprintf(errmsg, "invalid command suffix");
 718                                         return ERR;
 719                                 }
 720                         }
 721                 } while (sflags && *ibufp != '\n');
 722                 if (sflags && !pat) {
 723                         sprintf(errmsg, "no previous substitution");
 724                         return ERR;
 725                 } else if (sflags & SGG)
 726                         sgnum = 0;              /* override numeric arg */
 727                 if (*ibufp != '\n' && *(ibufp + 1) == '\n') {
 728                         sprintf(errmsg, "invalid pattern delimiter");
 729                         return ERR;
 730                 }
 731                 tpat = pat;
 732                 SPL1();
 733                 if ((!sflags || (sflags & SGR)) &&
 734                     (tpat = get_compiled_pattern()) == NULL) {
 735                         SPL0();
 736                         return ERR;
 737                 } else if (tpat != pat) {
 738                         if (pat) {
 739                                 regfree(pat);
 740                                 free(pat);
 741                         }
 742                         pat = tpat;
 743                         patlock = 1;            /* reserve pattern */
 744                 }
 745                 SPL0();
 746                 if (!sflags && extract_subst_tail(&sgflag, &sgnum) < 0)
 747                         return ERR;
 748                 else if (isglobal)
 749                         sgflag |= GLB;
 750                 else
 751                         sgflag &= ~GLB;
 752                 if (sflags & SGG)
 753                         sgflag ^= GSG;
 754                 if (sflags & SGP)
 755                         sgflag ^= GPR, sgflag &= ~(GLS | GNP);
 756                 do {
 757                         switch(*ibufp) {
 758                         case 'p':
 759                                 sgflag |= GPR, ibufp++;
 760                                 break;
 761                         case 'l':
 762                                 sgflag |= GLS, ibufp++;
 763                                 break;
 764                         case 'n':
 765                                 sgflag |= GNP, ibufp++;
 766                                 break;
 767                         default:
 768                                 n++;
 769                         }
 770                 } while (!n);
 771                 if (check_addr_range(current_addr, current_addr) < 0)
 772                         return ERR;
 773                 GET_COMMAND_SUFFIX();
 774                 if (!isglobal) clear_undo_stack();
 775                 if (search_and_replace(pat, sgflag, sgnum) < 0)
 776                         return ERR;
 777                 break;
 778         case 't':
 779                 if (check_addr_range(current_addr, current_addr) < 0)
 780                         return ERR;
 781                 GET_THIRD_ADDR(addr);
 782                 GET_COMMAND_SUFFIX();
 783                 if (!isglobal) clear_undo_stack();
 784                 if (copy_lines(addr) < 0)
 785                         return ERR;
 786                 break;
 787         case 'u':
 788                 if (addr_cnt > 0) {
 789                         sprintf(errmsg, "unexpected address");
 790                         return ERR;
 791                 }
 792                 GET_COMMAND_SUFFIX();
 793                 if (pop_undo_stack() < 0)
 794                         return ERR;
 795                 break;
 796         case 'w':
 797         case 'W':
 798                 if ((n = *ibufp) == 'q' || n == 'Q') {
 799                         gflag = EOF;
 800                         ibufp++;
 801                 }
 802                 if (!isspace((unsigned char)*ibufp)) {
 803                         sprintf(errmsg, "unexpected command suffix");
 804                         return ERR;
 805                 } else if ((fnp = get_filename()) == NULL)
 806                         return ERR;
 807                 if (addr_cnt == 0 && !addr_last)
 808                         first_addr = second_addr = 0;
 809                 else if (check_addr_range(1, addr_last) < 0)
 810                         return ERR;
 811                 GET_COMMAND_SUFFIX();
 812                 if (*old_filename == '\0' && *fnp != '!')
 813                         strlcpy(old_filename, fnp, sizeof(old_filename) - 2);
 814 #ifdef BACKWARDS
 815                 if (*fnp == '\0' && *old_filename == '\0') {
 816                         sprintf(errmsg, "no current filename");
 817                         return ERR;
 818                 }
 819 #endif
 820                 if ((addr = write_file(*fnp ? fnp : old_filename,
 821                     (c == 'W') ? "a" : "w", first_addr, second_addr)) < 0)
 822                         return ERR;
 823                 else if (addr == addr_last)
 824                         modified = 0;
 825                 else if (modified && !scripted && n == 'q')
 826                         gflag = EMOD;
 827                 break;
 828         case 'x':
 829                 if (addr_cnt > 0) {
 830                         sprintf(errmsg, "unexpected address");
 831                         return ERR;
 832                 }
 833                 GET_COMMAND_SUFFIX();
 834 #ifdef DES
 835                 des = get_keyword();
 836 #else
 837                 sprintf(errmsg, "crypt unavailable");
 838                 return ERR;
 839 #endif
 840                 break;
 841         case 'z':
 842 #ifdef BACKWARDS
 843                 if (check_addr_range(first_addr = 1, current_addr + 1) < 0)
 844 #else
 845                 if (check_addr_range(first_addr = 1, current_addr + !isglobal) < 0)
 846 #endif
 847                         return ERR;
 848                 else if ('0' < *ibufp && *ibufp <= '9')
 849                         STRTOL(rows, ibufp);
 850                 GET_COMMAND_SUFFIX();
 851                 if (display_lines(second_addr, min(addr_last,
 852                     second_addr + rows), gflag) < 0)
 853                         return ERR;
 854                 gflag = 0;
 855                 break;
 856         case '=':
 857                 GET_COMMAND_SUFFIX();
 858                 printf("%ld\n", addr_cnt ? second_addr : addr_last);
 859                 break;
 860         case '!':
 861                 if (addr_cnt > 0) {
 862                         sprintf(errmsg, "unexpected address");
 863                         return ERR;
 864                 } else if ((sflags = get_shell_command()) < 0)
 865                         return ERR;
 866                 GET_COMMAND_SUFFIX();
 867                 if (sflags) printf("%s\n", shcmd + 1);
 868                 system(shcmd + 1);
 869                 if (!scripted) printf("!\n");
 870                 break;
 871         case '\n':
 872 #ifdef BACKWARDS
 873                 if (check_addr_range(first_addr = 1, current_addr + 1) < 0
 874 #else
 875                 if (check_addr_range(first_addr = 1, current_addr + !isglobal) < 0
 876 #endif
 877                  || display_lines(second_addr, second_addr, 0) < 0)
 878                         return ERR;
 879                 break;
 880         default:
 881                 sprintf(errmsg, "unknown command");
 882                 return ERR;
 883         }
 884         return gflag;
 885 }
 886
 887
 888 /* check_addr_range: return status of address range check */
 889 int
 890 check_addr_range(long n, long m)
 891 {
 892         if (addr_cnt == 0) {
 893                 first_addr = n;
 894                 second_addr = m;
 895         }
 896         if (first_addr > second_addr || 1 > first_addr ||
 897             second_addr > addr_last) {
 898                 sprintf(errmsg, "invalid address");
 899                 return ERR;
 900         }
 901         return 0;
 902 }
 903
 904
 905 /* get_matching_node_addr: return the address of the next line matching a
 906    pattern in a given direction.  wrap around begin/end of editor buffer if
 907    necessary */
 908 long
 909 get_matching_node_addr(pattern_t *pat, int dir)
 910 {
 911         char *s;
 912         long n = current_addr;
 913         line_t *lp;
 914
 915         if (!pat) return ERR;
 916         do {
 917                 if ((n = dir ? INC_MOD(n, addr_last) :
 918                     DEC_MOD(n, addr_last)) != 0) {
 919                         lp = get_addressed_line_node(n);
 920                         if ((s = get_sbuf_line(lp)) == NULL)
 921                                 return ERR;
 922                         if (isbinary)
 923                                 NUL_TO_NEWLINE(s, lp->len);
 924                         if (!regexec(pat, s, 0, NULL, 0))
 925                                 return n;
 926                 }
 927         } while (n != current_addr);
 928         sprintf(errmsg, "no match");
 929         return  ERR;
 930 }
 931
 932
 933 /* get_filename: return pointer to copy of filename in the command buffer */
 934 char *
 935 get_filename(void)
 936 {
 937         static char *file = NULL;
 938         static int filesz = 0;
 939
 940         int n;
 941
 942         if (*ibufp != '\n') {
 943                 SKIP_BLANKS();
 944                 if (*ibufp == '\n') {
 945                         sprintf(errmsg, "invalid filename");
 946                         return NULL;
 947                 } else if ((ibufp = get_extended_line(&n, 1)) == NULL)
 948                         return NULL;
 949                 else if (*ibufp == '!') {
 950                         ibufp++;
 951                         if ((n = get_shell_command()) < 0)
 952                                 return NULL;
 953                         if (n) printf("%s\n", shcmd + 1);
 954                         return shcmd;
 955                 } else if (n - 1 > MAXPATHLEN) {
 956                         sprintf(errmsg, "filename too long");
 957                         return  NULL;
 958                 }
 959         }
 960 #ifndef BACKWARDS
 961         else if (*old_filename == '\0') {
 962                 sprintf(errmsg, "no current filename");
 963                 return  NULL;
 964         }
 965 #endif
 966         REALLOC(file, filesz, MAXPATHLEN + 1, NULL);
 967         for (n = 0; *ibufp != '\n';)
 968                 file[n++] = *ibufp++;
 969         file[n] = '\0';
 970         return is_legal_filename(file) ? file : NULL;
 971 }
 972
 973
 974 /* get_shell_command: read a shell command from stdin; return substitution
 975    status */
 976 int
 977 get_shell_command(void)
 978 {
 979         static char *buf = NULL;
 980         static int n = 0;
 981
 982         char *s;                        /* substitution char pointer */
 983         int i = 0;
 984         int j = 0;
 985
 986         if (red) {
 987                 sprintf(errmsg, "shell access restricted");
 988                 return ERR;
 989         } else if ((s = ibufp = get_extended_line(&j, 1)) == NULL)
 990                 return ERR;
 991         REALLOC(buf, n, j + 1, ERR);
 992         buf[i++] = '!';                 /* prefix command w/ bang */
 993         while (*ibufp != '\n')
 994                 switch (*ibufp) {
 995                 default:
 996                         REALLOC(buf, n, i + 2, ERR);
 997                         buf[i++] = *ibufp;
 998                         if (*ibufp++ == '\\')
 999                                 buf[i++] = *ibufp++;
1000                         break;
1001                 case '!':
1002                         if (s != ibufp) {
1003                                 REALLOC(buf, n, i + 1, ERR);
1004                                 buf[i++] = *ibufp++;
1005                         }
1006 #ifdef BACKWARDS
1007                         else if (shcmd == NULL || *(shcmd + 1) == '\0')
1008 #else
1009                         else if (shcmd == NULL)
1010 #endif
1011                         {
1012                                 sprintf(errmsg, "no previous command");
1013                                 return ERR;
1014                         } else {
1015                                 REALLOC(buf, n, i + shcmdi, ERR);
1016                                 for (s = shcmd + 1; s < shcmd + shcmdi;)
1017                                         buf[i++] = *s++;
1018                                 s = ibufp++;
1019                         }
1020                         break;
1021                 case '%':
1022                         if (*old_filename  == '\0') {
1023                                 sprintf(errmsg, "no current filename");
1024                                 return ERR;
1025                         }
1026                         j = strlen(s = strip_escapes(old_filename));
1027                         REALLOC(buf, n, i + j, ERR);
1028                         while (j--)
1029                                 buf[i++] = *s++;
1030                         s = ibufp++;
1031                         break;
1032                 }
1033         REALLOC(shcmd, shcmdsz, i + 1, ERR);
1034         memcpy(shcmd, buf, i);
1035         shcmd[shcmdi = i] = '\0';
1036         return *s == '!' || *s == '%';
1037 }
1038
1039
1040 /* append_lines: insert text from stdin to after line n; stop when either a
1041    single period is read or EOF; return status */
1042 int
1043 append_lines(long n)
1044 {
1045         int l;
1046         char *lp = ibuf;
1047         char *eot;
1048         undo_t *up = NULL;
1049
1050         for (current_addr = n;;) {
1051                 if (!isglobal) {
1052                         if ((l = get_tty_line()) < 0)
1053                                 return ERR;
1054                         else if (l == 0 || ibuf[l - 1] != '\n') {
1055                                 clearerr(stdin);
1056                                 return  l ? EOF : 0;
1057                         }
1058                         lp = ibuf;
1059                 } else if (*(lp = ibufp) == '\0')
1060                         return 0;
1061                 else {
1062                         while (*ibufp++ != '\n')
1063                                 ;
1064                         l = ibufp - lp;
1065                 }
1066                 if (l == 2 && lp[0] == '.' && lp[1] == '\n') {
1067                         return 0;
1068                 }
1069                 eot = lp + l;
1070                 SPL1();
1071                 do {
1072                         if ((lp = put_sbuf_line(lp)) == NULL) {
1073                                 SPL0();
1074                                 return ERR;
1075                         } else if (up)
1076                                 up->t = get_addressed_line_node(current_addr);
1077                         else if ((up = push_undo_stack(UADD, current_addr,
1078                             current_addr)) == NULL) {
1079                                 SPL0();
1080                                 return ERR;
1081                         }
1082                 } while (lp != eot);
1083                 modified = 1;
1084                 SPL0();
1085         }
1086         /* NOTREACHED */
1087 }
1088
1089
1090 /* join_lines: replace a range of lines with the joined text of those lines */
1091 int
1092 join_lines(long from, long to)
1093 {
1094         static char *buf = NULL;
1095         static int n;
1096
1097         char *s;
1098         int size = 0;
1099         line_t *bp, *ep;
1100
1101         ep = get_addressed_line_node(INC_MOD(to, addr_last));
1102         bp = get_addressed_line_node(from);
1103         for (; bp != ep; bp = bp->q_forw) {
1104                 if ((s = get_sbuf_line(bp)) == NULL)
1105                         return ERR;
1106                 REALLOC(buf, n, size + bp->len, ERR);
1107                 memcpy(buf + size, s, bp->len);
1108                 size += bp->len;
1109         }
1110         REALLOC(buf, n, size + 2, ERR);
1111         memcpy(buf + size, "\n", 2);
1112         if (delete_lines(from, to) < 0)
1113                 return ERR;
1114         current_addr = from - 1;
1115         SPL1();
1116         if (put_sbuf_line(buf) == NULL ||
1117             push_undo_stack(UADD, current_addr, current_addr) == NULL) {
1118                 SPL0();
1119                 return ERR;
1120         }
1121         modified = 1;
1122         SPL0();
1123         return 0;
1124 }
1125
1126
1127 /* move_lines: move a range of lines */
1128 int
1129 move_lines(long addr)
1130 {
1131         line_t *b1, *a1, *b2, *a2;
1132         long n = INC_MOD(second_addr, addr_last);
1133         long p = first_addr - 1;
1134         int done = (addr == first_addr - 1 || addr == second_addr);
1135
1136         SPL1();
1137         if (done) {
1138                 a2 = get_addressed_line_node(n);
1139                 b2 = get_addressed_line_node(p);
1140                 current_addr = second_addr;
1141         } else if (push_undo_stack(UMOV, p, n) == NULL ||
1142             push_undo_stack(UMOV, addr, INC_MOD(addr, addr_last)) == NULL) {
1143                 SPL0();
1144                 return ERR;
1145         } else {
1146                 a1 = get_addressed_line_node(n);
1147                 if (addr < first_addr) {
1148                         b1 = get_addressed_line_node(p);
1149                         b2 = get_addressed_line_node(addr);
1150                                         /* this get_addressed_line_node last! */
1151                 } else {
1152                         b2 = get_addressed_line_node(addr);
1153                         b1 = get_addressed_line_node(p);
1154                                         /* this get_addressed_line_node last! */
1155                 }
1156                 a2 = b2->q_forw;
1157                 REQUE(b2, b1->q_forw);
1158                 REQUE(a1->q_back, a2);
1159                 REQUE(b1, a1);
1160                 current_addr = addr + ((addr < first_addr) ?
1161                     second_addr - first_addr + 1 : 0);
1162         }
1163         if (isglobal)
1164                 unset_active_nodes(b2->q_forw, a2);
1165         modified = 1;
1166         SPL0();
1167         return 0;
1168 }
1169
1170
1171 /* copy_lines: copy a range of lines; return status */
1172 int
1173 copy_lines(long addr)
1174 {
1175         line_t *lp, *np = get_addressed_line_node(first_addr);
1176         undo_t *up = NULL;
1177         long n = second_addr - first_addr + 1;
1178         long m = 0;
1179
1180         current_addr = addr;
1181         if (first_addr <= addr && addr < second_addr) {
1182                 n =  addr - first_addr + 1;
1183                 m = second_addr - addr;
1184         }
1185         for (; n > 0; n=m, m=0, np = get_addressed_line_node(current_addr + 1))
1186                 for (; n-- > 0; np = np->q_forw) {
1187                         SPL1();
1188                         if ((lp = dup_line_node(np)) == NULL) {
1189                                 SPL0();
1190                                 return ERR;
1191                         }
1192                         add_line_node(lp);
1193                         if (up)
1194                                 up->t = lp;
1195                         else if ((up = push_undo_stack(UADD, current_addr,
1196                             current_addr)) == NULL) {
1197                                 SPL0();
1198                                 return ERR;
1199                         }
1200                         modified = 1;
1201                         SPL0();
1202                 }
1203         return 0;
1204 }
1205
1206
1207 /* delete_lines: delete a range of lines */
1208 int
1209 delete_lines(long from, long to)
1210 {
1211         line_t *n, *p;
1212
1213         SPL1();
1214         if (push_undo_stack(UDEL, from, to) == NULL) {
1215                 SPL0();
1216                 return ERR;
1217         }
1218         n = get_addressed_line_node(INC_MOD(to, addr_last));
1219         p = get_addressed_line_node(from - 1);
1220                                         /* this get_addressed_line_node last! */
1221         if (isglobal)
1222                 unset_active_nodes(p->q_forw, n);
1223         REQUE(p, n);
1224         addr_last -= to - from + 1;
1225         current_addr = from - 1;
1226         modified = 1;
1227         SPL0();
1228         return 0;
1229 }
1230
1231
1232 /* display_lines: print a range of lines to stdout */
1233 int
1234 display_lines(long from, long to, int gflag)
1235 {
1236         line_t *bp;
1237         line_t *ep;
1238         char *s;
1239
1240         if (!from) {
1241                 sprintf(errmsg, "invalid address");
1242                 return ERR;
1243         }
1244         ep = get_addressed_line_node(INC_MOD(to, addr_last));
1245         bp = get_addressed_line_node(from);
1246         for (; bp != ep; bp = bp->q_forw) {
1247                 if ((s = get_sbuf_line(bp)) == NULL)
1248                         return ERR;
1249                 if (put_tty_line(s, bp->len, current_addr = from++, gflag) < 0)
1250                         return ERR;
1251         }
1252         return 0;
1253 }
1254
1255
1256 #define MAXMARK 26                      /* max number of marks */
1257
1258 line_t  *mark[MAXMARK];                 /* line markers */
1259 int markno;                             /* line marker count */
1260
1261 /* mark_line_node: set a line node mark */
1262 int
1263 mark_line_node(line_t *lp, int n)
1264 {
1265         if (!islower(n)) {
1266                 sprintf(errmsg, "invalid mark character");
1267                 return ERR;
1268         } else if (mark[n - 'a'] == NULL)
1269                 markno++;
1270         mark[n - 'a'] = lp;
1271         return 0;
1272 }
1273
1274
1275 /* get_marked_node_addr: return address of a marked line */
1276 long
1277 get_marked_node_addr(int n)
1278 {
1279         if (!islower(n)) {
1280                 sprintf(errmsg, "invalid mark character");
1281                 return ERR;
1282         }
1283         return get_line_node_addr(mark[n - 'a']);
1284 }
1285
1286
1287 /* unmark_line_node: clear line node mark */
1288 void
1289 unmark_line_node(line_t *lp)
1290 {
1291         int i;
1292
1293         for (i = 0; markno && i < MAXMARK; i++)
1294                 if (mark[i] == lp) {
1295                         mark[i] = NULL;
1296                         markno--;
1297                 }
1298 }
1299
1300
1301 /* dup_line_node: return a pointer to a copy of a line node */
1302 line_t *
1303 dup_line_node(line_t *lp)
1304 {
1305         line_t *np;
1306
1307         if ((np = (line_t *) malloc(sizeof(line_t))) == NULL) {
1308                 fprintf(stderr, "%s\n", strerror(errno));
1309                 sprintf(errmsg, "out of memory");
1310                 return NULL;
1311         }
1312         np->seek = lp->seek;
1313         np->len = lp->len;
1314         return np;
1315 }
1316
1317
1318 /* has_trailing_escape:  return the parity of escapes preceding a character
1319    in a string */
1320 int
1321 has_trailing_escape(char *s, char *t)
1322 {
1323     return (s == t || *(t - 1) != '\\') ? 0 : !has_trailing_escape(s, t - 1);
1324 }
1325
1326
1327 /* strip_escapes: return copy of escaped string of at most length MAXPATHLEN */
1328 char *
1329 strip_escapes(const char *s)
1330 {
1331         static char *file = NULL;
1332         static int filesz = 0;
1333
1334         int i = 0;
1335
1336         REALLOC(file, filesz, MAXPATHLEN + 1, NULL);
1337         while ((i < (filesz - 1)) &&
1338                (file[i++] = (*s == '\\') != '\0' ? *++s : *s))
1339                 s++;
1340         file[filesz - 1] = '\0';
1341         return file;
1342 }
1343
1344
1345 void
1346 signal_hup(int signo)
1347 {
1348         if (mutex)
1349                 sigflags |= (1 << (signo - 1));
1350         else    handle_hup(signo);
1351 }
1352
1353
1354 void
1355 signal_int(int signo)
1356 {
1357         if (mutex)
1358                 sigflags |= (1 << (signo - 1));
1359         else    handle_int(signo);
1360 }
1361
1362
1363 void
1364 handle_hup(int signo)
1365 {
1366         char *hup = NULL;               /* hup filename */
1367         char *s;
1368         int n;
1369
1370         if (!sigactive)
1371                 quit(1);
1372         sigflags &= ~(1 << (signo - 1));
1373         if (addr_last && write_file("ed.hup", "w", 1, addr_last) < 0 &&
1374             (s = getenv("HOME")) != NULL &&
1375             (n = strlen(s)) + 8 <= MAXPATHLEN &&        /* "ed.hup" + '/' */
1376             (hup = (char *) malloc(n + 10)) != NULL) {
1377                 strcpy(hup, s);
1378                 if (hup[n - 1] != '/')
1379                         hup[n] = '/', hup[n+1] = '\0';
1380                 strcat(hup, "ed.hup");
1381                 write_file(hup, "w", 1, addr_last);
1382         }
1383         quit(2);
1384 }
1385
1386
1387 void
1388 handle_int(int signo)
1389 {
1390         if (!sigactive)
1391                 quit(1);
1392         sigflags &= ~(1 << (signo - 1));
1393 #ifdef _POSIX_SOURCE
1394         siglongjmp(env, -1);
1395 #else
1396         longjmp(env, -1);
1397 #endif
1398 }
1399
1400
1401 int cols = 72;                          /* wrap column */
1402
1403 void
1404 handle_winch(int signo)
1405 {
1406         struct winsize ws;              /* window size structure */
1407
1408         sigflags &= ~(1 << (signo - 1));
1409         if (ioctl(0, TIOCGWINSZ, (char *) &ws) >= 0) {
1410                 if (ws.ws_row > 2) rows = ws.ws_row - 2;
1411                 if (ws.ws_col > 8) cols = ws.ws_col - 8;
1412         }
1413 }
1414
1415
1416 /* is_legal_filename: return a legal filename */
1417 int
1418 is_legal_filename(char *s)
1419 {
1420         if (red && (*s == '!' || !strcmp(s, "..") || strchr(s, '/'))) {
1421                 sprintf(errmsg, "shell access restricted");
1422                 return 0;
1423         }
1424         return 1;
1425 }