bin/ed/main.c

   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  * @(#) Copyright (c) 1993 Andrew Moore, Talke Studio. All rights reserved.
  29  * @(#)main.c,v 1.1 1994/02/01 00:34:42 alm Exp
  30  * $FreeBSD: src/bin/ed/main.c,v 1.14.2.4 2001/08/01 02:36:03 obrien Exp $
  31  * $DragonFly: src/bin/ed/main.c,v 1.6 2004/09/26 16:32:47 asmodai Exp $
  32  */
  33
  34 /*
  35  * CREDITS
  36  *
  37  *      This program is based on the editor algorithm described in
  38  *      Brian W. Kernighan and P. J. Plauger's book "Software Tools
  39  *      in Pascal," Addison-Wesley, 1981.
  40  *
  41  *      The buffering algorithm is attributed to Rodney Ruddock of
  42  *      the University of Guelph, Guelph, Ontario.
  43  *
  44  *      The cbc.c encryption code is adapted from
  45  *      the bdes program by Matt Bishop of Dartmouth College,
  46  *      Hanover, NH.
  47  *
  48  */
  49
  50 #include <sys/types.h>
  51
  52 #include <sys/ioctl.h>
  53 #include <sys/wait.h>
  54 #include <ctype.h>
  55 #include <locale.h>
  56 #include <pwd.h>
  57 #include <setjmp.h>
  58
  59 #include "ed.h"
  60
  61
  62 #ifdef _POSIX_SOURCE
  63 sigjmp_buf env;
  64 #else
  65 jmp_buf env;
  66 #endif
  67
  68 /* static buffers */
  69 char stdinbuf[1];               /* stdin buffer */
  70 char *shcmd;                    /* shell command buffer */
  71 int shcmdsz;                    /* shell command buffer size */
  72 int shcmdi;                     /* shell command buffer index */
  73 char *ibuf;                     /* ed command-line buffer */
  74 int ibufsz;                     /* ed command-line buffer size */
  75 char *ibufp;                    /* pointer to ed command-line buffer */
  76
  77 /* global flags */
  78 int des = 0;                    /* if set, use crypt(3) for i/o */
  79 int garrulous = 0;              /* if set, print all error messages */
  80 int isbinary;                   /* if set, buffer contains ASCII NULs */
  81 int isglobal;                   /* if set, doing a global command */
  82 int modified;                   /* if set, buffer modified since last write */
  83 int mutex = 0;                  /* if set, signals set "sigflags" */
  84 int red = 0;                    /* if set, restrict shell/directory access */
  85 int scripted = 0;               /* if set, suppress diagnostics */
  86 int sigflags = 0;               /* if set, signals received while mutex set */
  87 int sigactive = 0;              /* if set, signal handlers are enabled */
  88
  89 char old_filename[PATH_MAX] = "";       /* default filename */
  90 long current_addr;              /* current address in editor buffer */
  91 long addr_last;                 /* last address in editor buffer */
  92 int lineno;                     /* script line number */
  93 const char *prompt;             /* command-line prompt */
  94 const char *dps = "*";          /* default command-line prompt */
  95
  96 const char usage[] = "usage: %s [-] [-sx] [-p string] [name]\n";
  97
  98 /* ed: line editor */
  99 int
 100 main(int argc, char **argv)
 101 {
 102         int c, n;
 103         long status = 0;
 104 #if __GNUC__
 105         /* Avoid longjmp clobbering */
 106         (void) &argc;
 107         (void) &argv;
 108 #endif
 109
 110         (void)setlocale(LC_ALL, "");
 111
 112         red = (n = strlen(argv[0])) > 2 && argv[0][n - 3] == 'r';
 113 top:
 114         while ((c = getopt(argc, argv, "p:sx")) != -1)
 115                 switch(c) {
 116                 case 'p':                               /* set prompt */
 117                         prompt = optarg;
 118                         break;
 119                 case 's':                               /* run script */
 120                         scripted = 1;
 121                         break;
 122                 case 'x':                               /* use crypt */
 123 #ifdef DES
 124                         des = get_keyword();
 125 #else
 126                         fprintf(stderr, "crypt unavailable\n?\n");
 127 #endif
 128                         break;
 129
 130                 default:
 131                         fprintf(stderr, usage, argv[0]);
 132                         exit(1);
 133                 }
 134         argv += optind;
 135         argc -= optind;
 136         if (argc && **argv == '-') {
 137                 scripted = 1;
 138                 if (argc > 1) {
 139                         optind = 1;
 140                         goto top;
 141                 }
 142                 argv++;
 143                 argc--;
 144         }
 145         /* assert: reliable signals! */
 146 #ifdef SIGWINCH
 147         handle_winch(SIGWINCH);
 148         if (isatty(0)) signal(SIGWINCH, handle_winch);
 149 #endif
 150         signal(SIGHUP, signal_hup);
 151         signal(SIGQUIT, SIG_IGN);
 152         signal(SIGINT, signal_int);
 153 #ifdef _POSIX_SOURCE
 154         if ((status = sigsetjmp(env, 1)))
 155 #else
 156         if ((status = setjmp(env)))
 157 #endif
 158         {
 159                 fputs("\n?\n", stderr);
 160                 sprintf(errmsg, "interrupt");
 161         } else {
 162                 init_buffers();
 163                 sigactive = 1;                  /* enable signal handlers */
 164                 if (argc && **argv && is_legal_filename(*argv)) {
 165                         if (read_file(*argv, 0) < 0 && !isatty(0))
 166                                 quit(2);
 167                         else if (**argv != '!')
 168                                 if (strlcpy(old_filename, *argv, sizeof(old_filename))
 169                                     >= sizeof(old_filename))
 170                                         quit(2);
 171                 } else if (argc) {
 172                         fputs("?\n", stderr);
 173                         if (**argv == '\0')
 174                                 sprintf(errmsg, "invalid filename");
 175                         if (!isatty(0))
 176                                 quit(2);
 177                 }
 178         }
 179         for (;;) {
 180                 if (status < 0 && garrulous)
 181                         fprintf(stderr, "%s\n", errmsg);
 182                 if (prompt) {
 183                         printf("%s", prompt);
 184                         fflush(stdout);
 185                 }
 186                 if ((n = get_tty_line()) < 0) {
 187                         status = ERR;
 188                         continue;
 189                 } else if (n == 0) {
 190                         if (modified && !scripted) {
 191                                 fputs("?\n", stderr);
 192                                 sprintf(errmsg, "warning: file modified");
 193                                 if (!isatty(0)) {
 194                                         fprintf(stderr, garrulous ?
 195                                             "script, line %d: %s\n" :
 196                                             "", lineno, errmsg);
 197                                         quit(2);
 198                                 }
 199                                 clearerr(stdin);
 200                                 modified = 0;
 201                                 status = EMOD;
 202                                 continue;
 203                         } else
 204                                 quit(0);
 205                 } else if (ibuf[n - 1] != '\n') {
 206                         /* discard line */
 207                         sprintf(errmsg, "unexpected end-of-file");
 208                         clearerr(stdin);
 209                         status = ERR;
 210                         continue;
 211                 }
 212                 isglobal = 0;
 213                 if ((status = extract_addr_range()) >= 0 &&
 214                     (status = exec_command()) >= 0)
 215                         if (!status ||
 216                             (status = display_lines(current_addr, current_addr,
 217                                 status)) >= 0)
 218                                 continue;
 219                 switch (status) {
 220                 case EOF:
 221                         quit(0);
 222                 case EMOD:
 223                         modified = 0;
 224                         fputs("?\n", stderr);           /* give warning */
 225                         sprintf(errmsg, "warning: file modified");
 226                         if (!isatty(0)) {
 227                                 fprintf(stderr, garrulous ?
 228                                     "script, line %d: %s\n" :
 229                                     "", lineno, errmsg);
 230                                 quit(2);
 231                         }
 232                         break;
 233                 case FATAL:
 234                         if (!isatty(0))
 235                                 fprintf(stderr, garrulous ?
 236                                     "script, line %d: %s\n" : "",
 237                                     lineno, errmsg);
 238                         else
 239                                 fprintf(stderr, garrulous ? "%s\n" : "",
 240                                     errmsg);
 241                         quit(3);
 242                 default:
 243                         fputs("?\n", stderr);
 244                         if (!isatty(0)) {
 245                                 fprintf(stderr, garrulous ?
 246                                     "script, line %d: %s\n" : "",
 247                                     lineno, errmsg);
 248                                 quit(2);
 249                         }
 250                         break;
 251                 }
 252         }
 253         /*NOTREACHED*/
 254 }
 255
 256 long first_addr, second_addr, addr_cnt;
 257
 258 /* extract_addr_range: get line addresses from the command buffer until an
 259    illegal address is seen; return status */
 260 int
 261 extract_addr_range(void)
 262 {
 263         long addr;
 264
 265         addr_cnt = 0;
 266         first_addr = second_addr = current_addr;
 267         while ((addr = next_addr()) >= 0) {
 268                 addr_cnt++;
 269                 first_addr = second_addr;
 270                 second_addr = addr;
 271                 if (*ibufp != ',' && *ibufp != ';')
 272                         break;
 273                 else if (*ibufp++ == ';')
 274                         current_addr = addr;
 275         }
 276         if ((addr_cnt = min(addr_cnt, 2)) == 1 || second_addr != addr)
 277                 first_addr = second_addr;
 278         return (addr == ERR) ? ERR : 0;
 279 }
 280
 281
 282 #define SKIP_BLANKS() while (isspace((unsigned char)*ibufp) && *ibufp != '\n') ibufp++
 283
 284 #define MUST_BE_FIRST() \
 285         if (!first) { sprintf(errmsg, "invalid address"); return ERR; }
 286
 287 /*  next_addr: return the next line address in the command buffer */
 288 long
 289 next_addr(void)
 290 {
 291         char *hd;
 292         long addr = current_addr;
 293         long n;
 294         int first = 1;
 295         int c;
 296
 297         SKIP_BLANKS();
 298         for (hd = ibufp;; first = 0)
 299                 switch (c = *ibufp) {
 300                 case '+':
 301                 case '\t':
 302                 case ' ':
 303                 case '-':
 304                 case '^':
 305                         ibufp++;
 306                         SKIP_BLANKS();
 307                         if (isdigit((unsigned char)*ibufp)) {
 308                                 STRTOL(n, ibufp);
 309                                 addr += (c == '-' || c == '^') ? -n : n;
 310                         } else if (!isspace((unsigned char)c))
 311                                 addr += (c == '-' || c == '^') ? -1 : 1;
 312                         break;
 313                 case '0': case '1': case '2':
 314                 case '3': case '4': case '5':
 315                 case '6': case '7': case '8': case '9':
 316                         MUST_BE_FIRST();
 317                         STRTOL(addr, ibufp);
 318                         break;
 319                 case '.':
 320                 case '$':
 321                         MUST_BE_FIRST();
 322                         ibufp++;
 323                         addr = (c == '.') ? current_addr : addr_last;
 324                         break;
 325                 case '/':
 326                 case '?':
 327                         MUST_BE_FIRST();
 328                         if ((addr = get_matching_node_addr(
 329                             get_compiled_pattern(), c == '/')) < 0)
 330                                 return ERR;
 331                         else if (c == *ibufp)
 332                                 ibufp++;
 333                         break;
 334                 case '\'':
 335                         MUST_BE_FIRST();
 336                         ibufp++;
 337                         if ((addr = get_marked_node_addr(*ibufp++)) < 0)
 338                                 return ERR;
 339                         break;
 340                 case '%':
 341                 case ',':
 342                 case ';':
 343                         if (first) {
 344                                 ibufp++;
 345                                 addr_cnt++;
 346                                 second_addr = (c == ';') ? current_addr : 1;
 347                                 addr = addr_last;
 348                                 break;
 349                         }
 350                         /* FALL THROUGH */
 351                 default:
 352                         if (ibufp == hd)
 353                                 return EOF;
 354                         else if (addr < 0 || addr_last < addr) {
 355                                 sprintf(errmsg, "invalid address");
 356                                 return ERR;
 357                         } else
 358                                 return addr;
 359                 }
 360         /* NOTREACHED */
 361 }
 362
 363
 364 #ifdef BACKWARDS
 365 /* GET_THIRD_ADDR: get a legal address from the command buffer */
 366 #define GET_THIRD_ADDR(addr) \
 367 { \
 368         long ol1, ol2; \
 369 \
 370         ol1 = first_addr, ol2 = second_addr; \
 371         if (extract_addr_range() < 0) \
 372                 return ERR; \
 373         else if (addr_cnt == 0) { \
 374                 sprintf(errmsg, "destination expected"); \
 375                 return ERR; \
 376         } else if (second_addr < 0 || addr_last < second_addr) { \
 377                 sprintf(errmsg, "invalid address"); \
 378                 return ERR; \
 379         } \
 380         addr = second_addr; \
 381         first_addr = ol1, second_addr = ol2; \
 382 }
 383 #else   /* BACKWARDS */
 384 /* GET_THIRD_ADDR: get a legal address from the command buffer */
 385 #define GET_THIRD_ADDR(addr) \
 386 { \
 387         long ol1, ol2; \
 388 \
 389         ol1 = first_addr, ol2 = second_addr; \
 390         if (extract_addr_range() < 0) \
 391                 return ERR; \
 392         if (second_addr < 0 || addr_last < second_addr) { \
 393                 sprintf(errmsg, "invalid address"); \
 394                 return ERR; \
 395         } \
 396         addr = second_addr; \
 397         first_addr = ol1, second_addr = ol2; \
 398 }
 399 #endif
 400
 401
 402 /* GET_COMMAND_SUFFIX: verify the command suffix in the command buffer */
 403 #define GET_COMMAND_SUFFIX() { \
 404         int done = 0; \
 405         do { \
 406                 switch(*ibufp) { \
 407                 case 'p': \
 408                         gflag |= GPR, ibufp++; \
 409                         break; \
 410                 case 'l': \
 411                         gflag |= GLS, ibufp++; \
 412                         break; \
 413                 case 'n': \
 414                         gflag |= GNP, ibufp++; \
 415                         break; \
 416                 default: \
 417                         done++; \
 418                 } \
 419         } while (!done); \
 420         if (*ibufp++ != '\n') { \
 421                 sprintf(errmsg, "invalid command suffix"); \
 422                 return ERR; \
 423         } \
 424 }
 425
 426
 427 /* sflags */
 428 #define SGG 001         /* complement previous global substitute suffix */
 429 #define SGP 002         /* complement previous print suffix */
 430 #define SGR 004         /* use last regex instead of last pat */
 431 #define SGF 010         /* repeat last substitution */
 432
 433 int patlock = 0;        /* if set, pattern not freed by get_compiled_pattern() */
 434
 435 long rows = 22;         /* scroll length: ws_row - 2 */
 436
 437 /* exec_command: execute the next command in command buffer; return print
 438    request, if any */
 439 int
 440 exec_command(void)
 441 {
 442         static pattern_t *pat = NULL;
 443         static int sgflag = 0;
 444         static long sgnum = 0;
 445
 446         pattern_t *tpat;
 447         char *fnp;
 448         int gflag = 0;
 449         int sflags = 0;
 450         long addr = 0;
 451         int n = 0;
 452         int c;
 453
 454         SKIP_BLANKS();
 455         switch(c = *ibufp++) {
 456         case 'a':
 457                 GET_COMMAND_SUFFIX();
 458                 if (!isglobal) clear_undo_stack();
 459                 if (append_lines(second_addr) < 0)
 460                         return ERR;
 461                 break;
 462         case 'c':
 463                 if (check_addr_range(current_addr, current_addr) < 0)
 464                         return ERR;
 465                 GET_COMMAND_SUFFIX();
 466                 if (!isglobal) clear_undo_stack();
 467                 if (delete_lines(first_addr, second_addr) < 0 ||
 468                     append_lines(current_addr) < 0)
 469                         return ERR;
 470                 break;
 471         case 'd':
 472                 if (check_addr_range(current_addr, current_addr) < 0)
 473                         return ERR;
 474                 GET_COMMAND_SUFFIX();
 475                 if (!isglobal) clear_undo_stack();
 476                 if (delete_lines(first_addr, second_addr) < 0)
 477                         return ERR;
 478                 else if ((addr = INC_MOD(current_addr, addr_last)) != 0)
 479                         current_addr = addr;
 480                 break;
 481         case 'e':
 482                 if (modified && !scripted)
 483                         return EMOD;
 484                 /* fall through */
 485         case 'E':
 486                 if (addr_cnt > 0) {
 487                         sprintf(errmsg, "unexpected address");
 488                         return ERR;
 489                 } else if (!isspace((unsigned char)*ibufp)) {
 490                         sprintf(errmsg, "unexpected command suffix");
 491                         return ERR;
 492                 } else if ((fnp = get_filename()) == NULL)
 493                         return ERR;
 494                 GET_COMMAND_SUFFIX();
 495                 if (delete_lines(1, addr_last) < 0)
 496                         return ERR;
 497                 clear_undo_stack();
 498                 if (close_sbuf() < 0)
 499                         return ERR;
 500                 else if (open_sbuf() < 0)
 501                         return FATAL;
 502                 if (*fnp && *fnp != '!') strcpy(old_filename, fnp);
 503 #ifdef BACKWARDS
 504                 if (*fnp == '\0' && *old_filename == '\0') {
 505                         sprintf(errmsg, "no current filename");
 506                         return ERR;
 507                 }
 508 #endif
 509                 if (read_file(*fnp ? fnp : old_filename, 0) < 0)
 510                         return ERR;
 511                 clear_undo_stack();
 512                 modified = 0;
 513                 u_current_addr = u_addr_last = -1;
 514                 break;
 515         case 'f':
 516                 if (addr_cnt > 0) {
 517                         sprintf(errmsg, "unexpected address");
 518                         return ERR;
 519                 } else if (!isspace((unsigned char)*ibufp)) {
 520                         sprintf(errmsg, "unexpected command suffix");
 521                         return ERR;
 522                 } else if ((fnp = get_filename()) == NULL)
 523                         return ERR;
 524                 else if (*fnp == '!') {
 525                         sprintf(errmsg, "invalid redirection");
 526                         return ERR;
 527                 }
 528                 GET_COMMAND_SUFFIX();
 529                 if (*fnp) strcpy(old_filename, fnp);
 530                 printf("%s\n", strip_escapes(old_filename));
 531                 break;
 532         case 'g':
 533         case 'v':
 534         case 'G':
 535         case 'V':
 536                 if (isglobal) {
 537                         sprintf(errmsg, "cannot nest global commands");
 538                         return ERR;
 539                 } else if (check_addr_range(1, addr_last) < 0)
 540                         return ERR;
 541                 else if (build_active_list(c == 'g' || c == 'G') < 0)
 542                         return ERR;
 543                 else if ((n = (c == 'G' || c == 'V')))
 544                         GET_COMMAND_SUFFIX();
 545                 isglobal++;
 546                 if (exec_global(n, gflag) < 0)
 547                         return ERR;
 548                 break;
 549         case 'h':
 550                 if (addr_cnt > 0) {
 551                         sprintf(errmsg, "unexpected address");
 552                         return ERR;
 553                 }
 554                 GET_COMMAND_SUFFIX();
 555                 if (*errmsg) fprintf(stderr, "%s\n", errmsg);
 556                 break;
 557         case 'H':
 558                 if (addr_cnt > 0) {
 559                         sprintf(errmsg, "unexpected address");
 560                         return ERR;
 561                 }
 562                 GET_COMMAND_SUFFIX();
 563                 if ((garrulous = 1 - garrulous) && *errmsg)
 564                         fprintf(stderr, "%s\n", errmsg);
 565                 break;
 566         case 'i':
 567                 if (second_addr == 0) {
 568                         sprintf(errmsg, "invalid address");
 569                         return ERR;
 570                 }
 571                 GET_COMMAND_SUFFIX();
 572                 if (!isglobal) clear_undo_stack();
 573                 if (append_lines(second_addr - 1) < 0)
 574                         return ERR;
 575                 break;
 576         case 'j':
 577                 if (check_addr_range(current_addr, current_addr + 1) < 0)
 578                         return ERR;
 579                 GET_COMMAND_SUFFIX();
 580                 if (!isglobal) clear_undo_stack();
 581                 if (first_addr != second_addr &&
 582                     join_lines(first_addr, second_addr) < 0)
 583                         return ERR;
 584                 break;
 585         case 'k':
 586                 c = *ibufp++;
 587                 if (second_addr == 0) {
 588                         sprintf(errmsg, "invalid address");
 589                         return ERR;
 590                 }
 591                 GET_COMMAND_SUFFIX();
 592                 if (mark_line_node(get_addressed_line_node(second_addr), c) < 0)
 593                         return ERR;
 594                 break;
 595         case 'l':
 596                 if (check_addr_range(current_addr, current_addr) < 0)
 597                         return ERR;
 598                 GET_COMMAND_SUFFIX();
 599                 if (display_lines(first_addr, second_addr, gflag | GLS) < 0)
 600                         return ERR;
 601                 gflag = 0;
 602                 break;
 603         case 'm':
 604                 if (check_addr_range(current_addr, current_addr) < 0)
 605                         return ERR;
 606                 GET_THIRD_ADDR(addr);
 607                 if (first_addr <= addr && addr < second_addr) {
 608                         sprintf(errmsg, "invalid destination");
 609                         return ERR;
 610                 }
 611                 GET_COMMAND_SUFFIX();
 612                 if (!isglobal) clear_undo_stack();
 613                 if (move_lines(addr) < 0)
 614                         return ERR;
 615                 break;
 616         case 'n':
 617                 if (check_addr_range(current_addr, current_addr) < 0)
 618                         return ERR;
 619                 GET_COMMAND_SUFFIX();
 620                 if (display_lines(first_addr, second_addr, gflag | GNP) < 0)
 621                         return ERR;
 622                 gflag = 0;
 623                 break;
 624         case 'p':
 625                 if (check_addr_range(current_addr, current_addr) < 0)
 626                         return ERR;
 627                 GET_COMMAND_SUFFIX();
 628                 if (display_lines(first_addr, second_addr, gflag | GPR) < 0)
 629                         return ERR;
 630                 gflag = 0;
 631                 break;
 632         case 'P':
 633                 if (addr_cnt > 0) {
 634                         sprintf(errmsg, "unexpected address");
 635                         return ERR;
 636                 }
 637                 GET_COMMAND_SUFFIX();
 638                 prompt = prompt ? NULL : optarg ? optarg : dps;
 639                 break;
 640         case 'q':
 641         case 'Q':
 642                 if (addr_cnt > 0) {
 643                         sprintf(errmsg, "unexpected address");
 644                         return ERR;
 645                 }
 646                 GET_COMMAND_SUFFIX();
 647                 gflag =  (modified && !scripted && c == 'q') ? EMOD : EOF;
 648                 break;
 649         case 'r':
 650                 if (!isspace((unsigned char)*ibufp)) {
 651                         sprintf(errmsg, "unexpected command suffix");
 652                         return ERR;
 653                 } else if (addr_cnt == 0)
 654                         second_addr = addr_last;
 655                 if ((fnp = get_filename()) == NULL)
 656                         return ERR;
 657                 GET_COMMAND_SUFFIX();
 658                 if (!isglobal) clear_undo_stack();
 659                 if (*old_filename == '\0' && *fnp != '!')
 660                         strcpy(old_filename, fnp);
 661 #ifdef BACKWARDS
 662                 if (*fnp == '\0' && *old_filename == '\0') {
 663                         sprintf(errmsg, "no current filename");
 664                         return ERR;
 665                 }
 666 #endif
 667                 if ((addr = read_file(*fnp ? fnp : old_filename, second_addr)) < 0)
 668                         return ERR;
 669                 else if (addr && addr != addr_last)
 670                         modified = 1;
 671                 break;
 672         case 's':
 673                 do {
 674                         switch(*ibufp) {
 675                         case '\n':
 676                                 sflags |=SGF;
 677                                 break;
 678                         case 'g':
 679                                 sflags |= SGG;
 680                                 ibufp++;
 681                                 break;
 682                         case 'p':
 683                                 sflags |= SGP;
 684                                 ibufp++;
 685                                 break;
 686                         case 'r':
 687                                 sflags |= SGR;
 688                                 ibufp++;
 689                                 break;
 690                         case '0': case '1': case '2': case '3': case '4':
 691                         case '5': case '6': case '7': case '8': case '9':
 692                                 STRTOL(sgnum, ibufp);
 693                                 sflags |= SGF;
 694                                 sgflag &= ~GSG;         /* override GSG */
 695                                 break;
 696                         default:
 697                                 if (sflags) {
 698                                         sprintf(errmsg, "invalid command suffix");
 699                                         return ERR;
 700                                 }
 701                         }
 702                 } while (sflags && *ibufp != '\n');
 703                 if (sflags && !pat) {
 704                         sprintf(errmsg, "no previous substitution");
 705                         return ERR;
 706                 } else if (sflags & SGG)
 707                         sgnum = 0;              /* override numeric arg */
 708                 if (*ibufp != '\n' && *(ibufp + 1) == '\n') {
 709                         sprintf(errmsg, "invalid pattern delimiter");
 710                         return ERR;
 711                 }
 712                 tpat = pat;
 713                 SPL1();
 714                 if ((!sflags || (sflags & SGR)) &&
 715                     (tpat = get_compiled_pattern()) == NULL) {
 716                         SPL0();
 717                         return ERR;
 718                 } else if (tpat != pat) {
 719                         if (pat) {
 720                                 regfree(pat);
 721                                 free(pat);
 722                         }
 723                         pat = tpat;
 724                         patlock = 1;            /* reserve pattern */
 725                 }
 726                 SPL0();
 727                 if (!sflags && extract_subst_tail(&sgflag, &sgnum) < 0)
 728                         return ERR;
 729                 else if (isglobal)
 730                         sgflag |= GLB;
 731                 else
 732                         sgflag &= ~GLB;
 733                 if (sflags & SGG)
 734                         sgflag ^= GSG;
 735                 if (sflags & SGP)
 736                         sgflag ^= GPR, sgflag &= ~(GLS | GNP);
 737                 do {
 738                         switch(*ibufp) {
 739                         case 'p':
 740                                 sgflag |= GPR, ibufp++;
 741                                 break;
 742                         case 'l':
 743                                 sgflag |= GLS, ibufp++;
 744                                 break;
 745                         case 'n':
 746                                 sgflag |= GNP, ibufp++;
 747                                 break;
 748                         default:
 749                                 n++;
 750                         }
 751                 } while (!n);
 752                 if (check_addr_range(current_addr, current_addr) < 0)
 753                         return ERR;
 754                 GET_COMMAND_SUFFIX();
 755                 if (!isglobal) clear_undo_stack();
 756                 if (search_and_replace(pat, sgflag, sgnum) < 0)
 757                         return ERR;
 758                 break;
 759         case 't':
 760                 if (check_addr_range(current_addr, current_addr) < 0)
 761                         return ERR;
 762                 GET_THIRD_ADDR(addr);
 763                 GET_COMMAND_SUFFIX();
 764                 if (!isglobal) clear_undo_stack();
 765                 if (copy_lines(addr) < 0)
 766                         return ERR;
 767                 break;
 768         case 'u':
 769                 if (addr_cnt > 0) {
 770                         sprintf(errmsg, "unexpected address");
 771                         return ERR;
 772                 }
 773                 GET_COMMAND_SUFFIX();
 774                 if (pop_undo_stack() < 0)
 775                         return ERR;
 776                 break;
 777         case 'w':
 778         case 'W':
 779                 if ((n = *ibufp) == 'q' || n == 'Q') {
 780                         gflag = EOF;
 781                         ibufp++;
 782                 }
 783                 if (!isspace((unsigned char)*ibufp)) {
 784                         sprintf(errmsg, "unexpected command suffix");
 785                         return ERR;
 786                 } else if ((fnp = get_filename()) == NULL)
 787                         return ERR;
 788                 if (addr_cnt == 0 && !addr_last)
 789                         first_addr = second_addr = 0;
 790                 else if (check_addr_range(1, addr_last) < 0)
 791                         return ERR;
 792                 GET_COMMAND_SUFFIX();
 793                 if (*old_filename == '\0' && *fnp != '!')
 794                         strcpy(old_filename, fnp);
 795 #ifdef BACKWARDS
 796                 if (*fnp == '\0' && *old_filename == '\0') {
 797                         sprintf(errmsg, "no current filename");
 798                         return ERR;
 799                 }
 800 #endif
 801                 if ((addr = write_file(*fnp ? fnp : old_filename,
 802                     (c == 'W') ? "a" : "w", first_addr, second_addr)) < 0)
 803                         return ERR;
 804                 else if (addr == addr_last)
 805                         modified = 0;
 806                 else if (modified && !scripted && n == 'q')
 807                         gflag = EMOD;
 808                 break;
 809         case 'x':
 810                 if (addr_cnt > 0) {
 811                         sprintf(errmsg, "unexpected address");
 812                         return ERR;
 813                 }
 814                 GET_COMMAND_SUFFIX();
 815 #ifdef DES
 816                 des = get_keyword();
 817 #else
 818                 sprintf(errmsg, "crypt unavailable");
 819                 return ERR;
 820 #endif
 821                 break;
 822         case 'z':
 823 #ifdef BACKWARDS
 824                 if (check_addr_range(first_addr = 1, current_addr + 1) < 0)
 825 #else
 826                 if (check_addr_range(first_addr = 1, current_addr + !isglobal) < 0)
 827 #endif
 828                         return ERR;
 829                 else if ('0' < *ibufp && *ibufp <= '9')
 830                         STRTOL(rows, ibufp);
 831                 GET_COMMAND_SUFFIX();
 832                 if (display_lines(second_addr, min(addr_last,
 833                     second_addr + rows), gflag) < 0)
 834                         return ERR;
 835                 gflag = 0;
 836                 break;
 837         case '=':
 838                 GET_COMMAND_SUFFIX();
 839                 printf("%ld\n", addr_cnt ? second_addr : addr_last);
 840                 break;
 841         case '!':
 842                 if (addr_cnt > 0) {
 843                         sprintf(errmsg, "unexpected address");
 844                         return ERR;
 845                 } else if ((sflags = get_shell_command()) < 0)
 846                         return ERR;
 847                 GET_COMMAND_SUFFIX();
 848                 if (sflags) printf("%s\n", shcmd + 1);
 849                 system(shcmd + 1);
 850                 if (!scripted) printf("!\n");
 851                 break;
 852         case '\n':
 853 #ifdef BACKWARDS
 854                 if (check_addr_range(first_addr = 1, current_addr + 1) < 0
 855 #else
 856                 if (check_addr_range(first_addr = 1, current_addr + !isglobal) < 0
 857 #endif
 858                  || display_lines(second_addr, second_addr, 0) < 0)
 859                         return ERR;
 860                 break;
 861         default:
 862                 sprintf(errmsg, "unknown command");
 863                 return ERR;
 864         }
 865         return gflag;
 866 }
 867
 868
 869 /* check_addr_range: return status of address range check */
 870 int
 871 check_addr_range(long n, long m)
 872 {
 873         if (addr_cnt == 0) {
 874                 first_addr = n;
 875                 second_addr = m;
 876         }
 877         if (first_addr > second_addr || 1 > first_addr ||
 878             second_addr > addr_last) {
 879                 sprintf(errmsg, "invalid address");
 880                 return ERR;
 881         }
 882         return 0;
 883 }
 884
 885
 886 /* get_matching_node_addr: return the address of the next line matching a
 887    pattern in a given direction.  wrap around begin/end of editor buffer if
 888    necessary */
 889 long
 890 get_matching_node_addr(pattern_t *pat, int dir)
 891 {
 892         char *s;
 893         long n = current_addr;
 894         line_t *lp;
 895
 896         if (!pat) return ERR;
 897         do {
 898                if ((n = dir ? INC_MOD(n, addr_last) : DEC_MOD(n, addr_last))) {
 899                         lp = get_addressed_line_node(n);
 900                         if ((s = get_sbuf_line(lp)) == NULL)
 901                                 return ERR;
 902                         if (isbinary)
 903                                 NUL_TO_NEWLINE(s, lp->len);
 904                         if (!regexec(pat, s, 0, NULL, 0))
 905                                 return n;
 906                }
 907         } while (n != current_addr);
 908         sprintf(errmsg, "no match");
 909         return  ERR;
 910 }
 911
 912
 913 /* get_filename: return pointer to copy of filename in the command buffer */
 914 char *
 915 get_filename(void)
 916 {
 917         static char *file = NULL;
 918         static int filesz = 0;
 919
 920         int n;
 921
 922         if (*ibufp != '\n') {
 923                 SKIP_BLANKS();
 924                 if (*ibufp == '\n') {
 925                         sprintf(errmsg, "invalid filename");
 926                         return NULL;
 927                 } else if ((ibufp = get_extended_line(&n, 1)) == NULL)
 928                         return NULL;
 929                 else if (*ibufp == '!') {
 930                         ibufp++;
 931                         if ((n = get_shell_command()) < 0)
 932                                 return NULL;
 933                         if (n)
 934                                 printf("%s\n", shcmd + 1);
 935                         return shcmd;
 936                 } else if (n > PATH_MAX - 1) {
 937                         sprintf(errmsg, "filename too long");
 938                         return  NULL;
 939                 }
 940         }
 941 #ifndef BACKWARDS
 942         else if (*old_filename == '\0') {
 943                 sprintf(errmsg, "no current filename");
 944                 return  NULL;
 945         }
 946 #endif
 947         REALLOC(file, filesz, PATH_MAX, NULL);
 948         for (n = 0; *ibufp != '\n';)
 949                 file[n++] = *ibufp++;
 950         file[n] = '\0';
 951         return is_legal_filename(file) ? file : NULL;
 952 }
 953
 954
 955 /* get_shell_command: read a shell command from stdin; return substitution
 956    status */
 957 int
 958 get_shell_command(void)
 959 {
 960         static char *buf = NULL;
 961         static int n = 0;
 962
 963         char *s;                        /* substitution char pointer */
 964         int i = 0;
 965         int j = 0;
 966
 967         if (red) {
 968                 sprintf(errmsg, "shell access restricted");
 969                 return ERR;
 970         } else if ((s = ibufp = get_extended_line(&j, 1)) == NULL)
 971                 return ERR;
 972         REALLOC(buf, n, j + 1, ERR);
 973         buf[i++] = '!';                 /* prefix command w/ bang */
 974         while (*ibufp != '\n')
 975                 switch (*ibufp) {
 976                 default:
 977                         REALLOC(buf, n, i + 2, ERR);
 978                         buf[i++] = *ibufp;
 979                         if (*ibufp++ == '\\')
 980                                 buf[i++] = *ibufp++;
 981                         break;
 982                 case '!':
 983                         if (s != ibufp) {
 984                                 REALLOC(buf, n, i + 1, ERR);
 985                                 buf[i++] = *ibufp++;
 986                         }
 987 #ifdef BACKWARDS
 988                         else if (shcmd == NULL || *(shcmd + 1) == '\0')
 989 #else
 990                         else if (shcmd == NULL)
 991 #endif
 992                         {
 993                                 sprintf(errmsg, "no previous command");
 994                                 return ERR;
 995                         } else {
 996                                 REALLOC(buf, n, i + shcmdi, ERR);
 997                                 for (s = shcmd + 1; s < shcmd + shcmdi;)
 998                                         buf[i++] = *s++;
 999                                 s = ibufp++;
1000                         }
1001                         break;
1002                 case '%':
1003                         if (*old_filename  == '\0') {
1004                                 sprintf(errmsg, "no current filename");
1005                                 return ERR;
1006                         }
1007                         j = strlen(s = strip_escapes(old_filename));
1008                         REALLOC(buf, n, i + j, ERR);
1009                         while (j--)
1010                                 buf[i++] = *s++;
1011                         s = ibufp++;
1012                         break;
1013                 }
1014         REALLOC(shcmd, shcmdsz, i + 1, ERR);
1015         memcpy(shcmd, buf, i);
1016         shcmd[shcmdi = i] = '\0';
1017         return *s == '!' || *s == '%';
1018 }
1019
1020
1021 /* append_lines: insert text from stdin to after line n; stop when either a
1022    single period is read or EOF; return status */
1023 int
1024 append_lines(long n)
1025 {
1026         int l;
1027         char *lp = ibuf;
1028         char *eot;
1029         undo_t *up = NULL;
1030
1031         for (current_addr = n;;) {
1032                 if (!isglobal) {
1033                         if ((l = get_tty_line()) < 0)
1034                                 return ERR;
1035                         else if (l == 0 || ibuf[l - 1] != '\n') {
1036                                 clearerr(stdin);
1037                                 return  l ? EOF : 0;
1038                         }
1039                         lp = ibuf;
1040                 } else if (*(lp = ibufp) == '\0')
1041                         return 0;
1042                 else {
1043                         while (*ibufp++ != '\n')
1044                                 ;
1045                         l = ibufp - lp;
1046                 }
1047                 if (l == 2 && lp[0] == '.' && lp[1] == '\n') {
1048                         return 0;
1049                 }
1050                 eot = lp + l;
1051                 SPL1();
1052                 do {
1053                         if ((lp = put_sbuf_line(lp)) == NULL) {
1054                                 SPL0();
1055                                 return ERR;
1056                         } else if (up)
1057                                 up->t = get_addressed_line_node(current_addr);
1058                         else if ((up = push_undo_stack(UADD, current_addr,
1059                             current_addr)) == NULL) {
1060                                 SPL0();
1061                                 return ERR;
1062                         }
1063                 } while (lp != eot);
1064                 modified = 1;
1065                 SPL0();
1066         }
1067         /* NOTREACHED */
1068 }
1069
1070
1071 /* join_lines: replace a range of lines with the joined text of those lines */
1072 int
1073 join_lines(long from, long to)
1074 {
1075         static char *buf = NULL;
1076         static int n;
1077
1078         char *s;
1079         int size = 0;
1080         line_t *bp, *ep;
1081
1082         ep = get_addressed_line_node(INC_MOD(to, addr_last));
1083         bp = get_addressed_line_node(from);
1084         for (; bp != ep; bp = bp->q_forw) {
1085                 if ((s = get_sbuf_line(bp)) == NULL)
1086                         return ERR;
1087                 REALLOC(buf, n, size + bp->len, ERR);
1088                 memcpy(buf + size, s, bp->len);
1089                 size += bp->len;
1090         }
1091         REALLOC(buf, n, size + 2, ERR);
1092         memcpy(buf + size, "\n", 2);
1093         if (delete_lines(from, to) < 0)
1094                 return ERR;
1095         current_addr = from - 1;
1096         SPL1();
1097         if (put_sbuf_line(buf) == NULL ||
1098             push_undo_stack(UADD, current_addr, current_addr) == NULL) {
1099                 SPL0();
1100                 return ERR;
1101         }
1102         modified = 1;
1103         SPL0();
1104         return 0;
1105 }
1106
1107
1108 /* move_lines: move a range of lines */
1109 int
1110 move_lines(long addr)
1111 {
1112         line_t *b1, *a1, *b2, *a2;
1113         long n = INC_MOD(second_addr, addr_last);
1114         long p = first_addr - 1;
1115         int done = (addr == first_addr - 1 || addr == second_addr);
1116
1117         SPL1();
1118         if (done) {
1119                 a2 = get_addressed_line_node(n);
1120                 b2 = get_addressed_line_node(p);
1121                 current_addr = second_addr;
1122         } else if (push_undo_stack(UMOV, p, n) == NULL ||
1123             push_undo_stack(UMOV, addr, INC_MOD(addr, addr_last)) == NULL) {
1124                 SPL0();
1125                 return ERR;
1126         } else {
1127                 a1 = get_addressed_line_node(n);
1128                 if (addr < first_addr) {
1129                         b1 = get_addressed_line_node(p);
1130                         b2 = get_addressed_line_node(addr);
1131                                         /* this get_addressed_line_node last! */
1132                 } else {
1133                         b2 = get_addressed_line_node(addr);
1134                         b1 = get_addressed_line_node(p);
1135                                         /* this get_addressed_line_node last! */
1136                 }
1137                 a2 = b2->q_forw;
1138                 REQUE(b2, b1->q_forw);
1139                 REQUE(a1->q_back, a2);
1140                 REQUE(b1, a1);
1141                 current_addr = addr + ((addr < first_addr) ?
1142                     second_addr - first_addr + 1 : 0);
1143         }
1144         if (isglobal)
1145                 unset_active_nodes(b2->q_forw, a2);
1146         modified = 1;
1147         SPL0();
1148         return 0;
1149 }
1150
1151
1152 /* copy_lines: copy a range of lines; return status */
1153 int
1154 copy_lines(long addr)
1155 {
1156         line_t *lp, *np = get_addressed_line_node(first_addr);
1157         undo_t *up = NULL;
1158         long n = second_addr - first_addr + 1;
1159         long m = 0;
1160
1161         current_addr = addr;
1162         if (first_addr <= addr && addr < second_addr) {
1163                 n =  addr - first_addr + 1;
1164                 m = second_addr - addr;
1165         }
1166         for (; n > 0; n=m, m=0, np = get_addressed_line_node(current_addr + 1))
1167                 for (; n-- > 0; np = np->q_forw) {
1168                         SPL1();
1169                         if ((lp = dup_line_node(np)) == NULL) {
1170                                 SPL0();
1171                                 return ERR;
1172                         }
1173                         add_line_node(lp);
1174                         if (up)
1175                                 up->t = lp;
1176                         else if ((up = push_undo_stack(UADD, current_addr,
1177                             current_addr)) == NULL) {
1178                                 SPL0();
1179                                 return ERR;
1180                         }
1181                         modified = 1;
1182                         SPL0();
1183                 }
1184         return 0;
1185 }
1186
1187
1188 /* delete_lines: delete a range of lines */
1189 int
1190 delete_lines(long from, long to)
1191 {
1192         line_t *n, *p;
1193
1194         SPL1();
1195         if (push_undo_stack(UDEL, from, to) == NULL) {
1196                 SPL0();
1197                 return ERR;
1198         }
1199         n = get_addressed_line_node(INC_MOD(to, addr_last));
1200         p = get_addressed_line_node(from - 1);
1201                                         /* this get_addressed_line_node last! */
1202         if (isglobal)
1203                 unset_active_nodes(p->q_forw, n);
1204         REQUE(p, n);
1205         addr_last -= to - from + 1;
1206         current_addr = from - 1;
1207         modified = 1;
1208         SPL0();
1209         return 0;
1210 }
1211
1212
1213 /* display_lines: print a range of lines to stdout */
1214 int
1215 display_lines(long from, long to, int gflag)
1216 {
1217         line_t *bp;
1218         line_t *ep;
1219         char *s;
1220
1221         if (!from) {
1222                 sprintf(errmsg, "invalid address");
1223                 return ERR;
1224         }
1225         ep = get_addressed_line_node(INC_MOD(to, addr_last));
1226         bp = get_addressed_line_node(from);
1227         for (; bp != ep; bp = bp->q_forw) {
1228                 if ((s = get_sbuf_line(bp)) == NULL)
1229                         return ERR;
1230                 if (put_tty_line(s, bp->len, current_addr = from++, gflag) < 0)
1231                         return ERR;
1232         }
1233         return 0;
1234 }
1235
1236
1237 #define MAXMARK 26                      /* max number of marks */
1238
1239 line_t  *mark[MAXMARK];                 /* line markers */
1240 int markno;                             /* line marker count */
1241
1242 /* mark_line_node: set a line node mark */
1243 int
1244 mark_line_node(line_t *lp, int n)
1245 {
1246         if (!islower((unsigned char)n)) {
1247                 sprintf(errmsg, "invalid mark character");
1248                 return ERR;
1249         } else if (mark[n - 'a'] == NULL)
1250                 markno++;
1251         mark[n - 'a'] = lp;
1252         return 0;
1253 }
1254
1255
1256 /* get_marked_node_addr: return address of a marked line */
1257 long
1258 get_marked_node_addr(int n)
1259 {
1260         if (!islower((unsigned char)n)) {
1261                 sprintf(errmsg, "invalid mark character");
1262                 return ERR;
1263         }
1264         return get_line_node_addr(mark[n - 'a']);
1265 }
1266
1267
1268 /* unmark_line_node: clear line node mark */
1269 void
1270 unmark_line_node(line_t *lp)
1271 {
1272         int i;
1273
1274         for (i = 0; markno && i < MAXMARK; i++)
1275                 if (mark[i] == lp) {
1276                         mark[i] = NULL;
1277                         markno--;
1278                 }
1279 }
1280
1281
1282 /* dup_line_node: return a pointer to a copy of a line node */
1283 line_t *
1284 dup_line_node(line_t *lp)
1285 {
1286         line_t *np;
1287
1288         if ((np = (line_t *) malloc(sizeof(line_t))) == NULL) {
1289                 fprintf(stderr, "%s\n", strerror(errno));
1290                 sprintf(errmsg, "out of memory");
1291                 return NULL;
1292         }
1293         np->seek = lp->seek;
1294         np->len = lp->len;
1295         return np;
1296 }
1297
1298
1299 /* has_trailing_escape:  return the parity of escapes preceding a character
1300    in a string */
1301 int
1302 has_trailing_escape(char *s, char *t)
1303 {
1304     return (s == t || *(t - 1) != '\\') ? 0 : !has_trailing_escape(s, t - 1);
1305 }
1306
1307
1308 /* strip_escapes: return copy of escaped string of at most length PATH_MAX */
1309 char *
1310 strip_escapes(const char *s)
1311 {
1312         static char *file = NULL;
1313         static int filesz = 0;
1314
1315         int i = 0;
1316
1317         REALLOC(file, filesz, PATH_MAX, NULL);
1318         while (i < filesz - 1   /* Worry about a possible trailing escape */
1319                && (file[i++] = (*s == '\\') ? *++s : *s))
1320                 s++;
1321         return file;
1322 }
1323
1324
1325 void
1326 signal_hup(int signo)
1327 {
1328         if (mutex)
1329                 sigflags |= (1 << (signo - 1));
1330         else
1331                 handle_hup(signo);
1332 }
1333
1334
1335 void
1336 signal_int(int signo)
1337 {
1338         if (mutex)
1339                 sigflags |= (1 << (signo - 1));
1340         else
1341                 handle_int(signo);
1342 }
1343
1344
1345 void
1346 handle_hup(int signo)
1347 {
1348         char *hup = NULL;               /* hup filename */
1349         char *s;
1350         int n;
1351
1352         if (!sigactive)
1353                 quit(1);
1354         sigflags &= ~(1 << (signo - 1));
1355         if (addr_last && write_file("ed.hup", "w", 1, addr_last) < 0 &&
1356             (s = getenv("HOME")) != NULL &&
1357             (n = strlen(s)) + 8 <= PATH_MAX &&  /* "ed.hup" + '/' */
1358             (hup = (char *) malloc(n + 10)) != NULL) {
1359                 strcpy(hup, s);
1360                 if (hup[n - 1] != '/')
1361                         hup[n] = '/', hup[n+1] = '\0';
1362                 strcat(hup, "ed.hup");
1363                 write_file(hup, "w", 1, addr_last);
1364         }
1365         quit(2);
1366 }
1367
1368
1369 void
1370 handle_int(int signo)
1371 {
1372         if (!sigactive)
1373                 quit(1);
1374         sigflags &= ~(1 << (signo - 1));
1375 #ifdef _POSIX_SOURCE
1376         siglongjmp(env, -1);
1377 #else
1378         longjmp(env, -1);
1379 #endif
1380 }
1381
1382
1383 int cols = 72;                          /* wrap column */
1384
1385 void
1386 handle_winch(int signo)
1387 {
1388         int save_errno = errno;
1389
1390         struct winsize ws;              /* window size structure */
1391
1392         sigflags &= ~(1 << (signo - 1));
1393         if (ioctl(0, TIOCGWINSZ, (char *) &ws) >= 0) {
1394                 if (ws.ws_row > 2) rows = ws.ws_row - 2;
1395                 if (ws.ws_col > 8) cols = ws.ws_col - 8;
1396         }
1397         errno = save_errno;
1398 }
1399
1400
1401 /* is_legal_filename: return a legal filename */
1402 int
1403 is_legal_filename(char *s)
1404 {
1405         if (red && (*s == '!' || !strcmp(s, "..") || strchr(s, '/'))) {
1406                 sprintf(errmsg, "shell access restricted");
1407                 return 0;
1408         }
1409         return 1;
1410 }