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 1.4 2004/03/19 17:47:48 cpressey 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         extern long u_current_addr;
 443         extern long u_addr_last;
 444
 445         static pattern_t *pat = NULL;
 446         static int sgflag = 0;
 447         static long sgnum = 0;
 448
 449         pattern_t *tpat;
 450         char *fnp;
 451         int gflag = 0;
 452         int sflags = 0;
 453         long addr = 0;
 454         int n = 0;
 455         int c;
 456
 457         SKIP_BLANKS();
 458         switch(c = *ibufp++) {
 459         case 'a':
 460                 GET_COMMAND_SUFFIX();
 461                 if (!isglobal) clear_undo_stack();
 462                 if (append_lines(second_addr) < 0)
 463                         return ERR;
 464                 break;
 465         case 'c':
 466                 if (check_addr_range(current_addr, current_addr) < 0)
 467                         return ERR;
 468                 GET_COMMAND_SUFFIX();
 469                 if (!isglobal) clear_undo_stack();
 470                 if (delete_lines(first_addr, second_addr) < 0 ||
 471                     append_lines(current_addr) < 0)
 472                         return ERR;
 473                 break;
 474         case 'd':
 475                 if (check_addr_range(current_addr, current_addr) < 0)
 476                         return ERR;
 477                 GET_COMMAND_SUFFIX();
 478                 if (!isglobal) clear_undo_stack();
 479                 if (delete_lines(first_addr, second_addr) < 0)
 480                         return ERR;
 481                 else if ((addr = INC_MOD(current_addr, addr_last)) != 0)
 482                         current_addr = addr;
 483                 break;
 484         case 'e':
 485                 if (modified && !scripted)
 486                         return EMOD;
 487                 /* fall through */
 488         case 'E':
 489                 if (addr_cnt > 0) {
 490                         sprintf(errmsg, "unexpected address");
 491                         return ERR;
 492                 } else if (!isspace((unsigned char)*ibufp)) {
 493                         sprintf(errmsg, "unexpected command suffix");
 494                         return ERR;
 495                 } else if ((fnp = get_filename()) == NULL)
 496                         return ERR;
 497                 GET_COMMAND_SUFFIX();
 498                 if (delete_lines(1, addr_last) < 0)
 499                         return ERR;
 500                 clear_undo_stack();
 501                 if (close_sbuf() < 0)
 502                         return ERR;
 503                 else if (open_sbuf() < 0)
 504                         return FATAL;
 505                 if (*fnp && *fnp != '!') strcpy(old_filename, fnp);
 506 #ifdef BACKWARDS
 507                 if (*fnp == '\0' && *old_filename == '\0') {
 508                         sprintf(errmsg, "no current filename");
 509                         return ERR;
 510                 }
 511 #endif
 512                 if (read_file(*fnp ? fnp : old_filename, 0) < 0)
 513                         return ERR;
 514                 clear_undo_stack();
 515                 modified = 0;
 516                 u_current_addr = u_addr_last = -1;
 517                 break;
 518         case 'f':
 519                 if (addr_cnt > 0) {
 520                         sprintf(errmsg, "unexpected address");
 521                         return ERR;
 522                 } else if (!isspace((unsigned char)*ibufp)) {
 523                         sprintf(errmsg, "unexpected command suffix");
 524                         return ERR;
 525                 } else if ((fnp = get_filename()) == NULL)
 526                         return ERR;
 527                 else if (*fnp == '!') {
 528                         sprintf(errmsg, "invalid redirection");
 529                         return ERR;
 530                 }
 531                 GET_COMMAND_SUFFIX();
 532                 if (*fnp) strcpy(old_filename, fnp);
 533                 printf("%s\n", strip_escapes(old_filename));
 534                 break;
 535         case 'g':
 536         case 'v':
 537         case 'G':
 538         case 'V':
 539                 if (isglobal) {
 540                         sprintf(errmsg, "cannot nest global commands");
 541                         return ERR;
 542                 } else if (check_addr_range(1, addr_last) < 0)
 543                         return ERR;
 544                 else if (build_active_list(c == 'g' || c == 'G') < 0)
 545                         return ERR;
 546                 else if ((n = (c == 'G' || c == 'V')))
 547                         GET_COMMAND_SUFFIX();
 548                 isglobal++;
 549                 if (exec_global(n, gflag) < 0)
 550                         return ERR;
 551                 break;
 552         case 'h':
 553                 if (addr_cnt > 0) {
 554                         sprintf(errmsg, "unexpected address");
 555                         return ERR;
 556                 }
 557                 GET_COMMAND_SUFFIX();
 558                 if (*errmsg) fprintf(stderr, "%s\n", errmsg);
 559                 break;
 560         case 'H':
 561                 if (addr_cnt > 0) {
 562                         sprintf(errmsg, "unexpected address");
 563                         return ERR;
 564                 }
 565                 GET_COMMAND_SUFFIX();
 566                 if ((garrulous = 1 - garrulous) && *errmsg)
 567                         fprintf(stderr, "%s\n", errmsg);
 568                 break;
 569         case 'i':
 570                 if (second_addr == 0) {
 571                         sprintf(errmsg, "invalid address");
 572                         return ERR;
 573                 }
 574                 GET_COMMAND_SUFFIX();
 575                 if (!isglobal) clear_undo_stack();
 576                 if (append_lines(second_addr - 1) < 0)
 577                         return ERR;
 578                 break;
 579         case 'j':
 580                 if (check_addr_range(current_addr, current_addr + 1) < 0)
 581                         return ERR;
 582                 GET_COMMAND_SUFFIX();
 583                 if (!isglobal) clear_undo_stack();
 584                 if (first_addr != second_addr &&
 585                     join_lines(first_addr, second_addr) < 0)
 586                         return ERR;
 587                 break;
 588         case 'k':
 589                 c = *ibufp++;
 590                 if (second_addr == 0) {
 591                         sprintf(errmsg, "invalid address");
 592                         return ERR;
 593                 }
 594                 GET_COMMAND_SUFFIX();
 595                 if (mark_line_node(get_addressed_line_node(second_addr), c) < 0)
 596                         return ERR;
 597                 break;
 598         case 'l':
 599                 if (check_addr_range(current_addr, current_addr) < 0)
 600                         return ERR;
 601                 GET_COMMAND_SUFFIX();
 602                 if (display_lines(first_addr, second_addr, gflag | GLS) < 0)
 603                         return ERR;
 604                 gflag = 0;
 605                 break;
 606         case 'm':
 607                 if (check_addr_range(current_addr, current_addr) < 0)
 608                         return ERR;
 609                 GET_THIRD_ADDR(addr);
 610                 if (first_addr <= addr && addr < second_addr) {
 611                         sprintf(errmsg, "invalid destination");
 612                         return ERR;
 613                 }
 614                 GET_COMMAND_SUFFIX();
 615                 if (!isglobal) clear_undo_stack();
 616                 if (move_lines(addr) < 0)
 617                         return ERR;
 618                 break;
 619         case 'n':
 620                 if (check_addr_range(current_addr, current_addr) < 0)
 621                         return ERR;
 622                 GET_COMMAND_SUFFIX();
 623                 if (display_lines(first_addr, second_addr, gflag | GNP) < 0)
 624                         return ERR;
 625                 gflag = 0;
 626                 break;
 627         case 'p':
 628                 if (check_addr_range(current_addr, current_addr) < 0)
 629                         return ERR;
 630                 GET_COMMAND_SUFFIX();
 631                 if (display_lines(first_addr, second_addr, gflag | GPR) < 0)
 632                         return ERR;
 633                 gflag = 0;
 634                 break;
 635         case 'P':
 636                 if (addr_cnt > 0) {
 637                         sprintf(errmsg, "unexpected address");
 638                         return ERR;
 639                 }
 640                 GET_COMMAND_SUFFIX();
 641                 prompt = prompt ? NULL : optarg ? optarg : dps;
 642                 break;
 643         case 'q':
 644         case 'Q':
 645                 if (addr_cnt > 0) {
 646                         sprintf(errmsg, "unexpected address");
 647                         return ERR;
 648                 }
 649                 GET_COMMAND_SUFFIX();
 650                 gflag =  (modified && !scripted && c == 'q') ? EMOD : EOF;
 651                 break;
 652         case 'r':
 653                 if (!isspace((unsigned char)*ibufp)) {
 654                         sprintf(errmsg, "unexpected command suffix");
 655                         return ERR;
 656                 } else if (addr_cnt == 0)
 657                         second_addr = addr_last;
 658                 if ((fnp = get_filename()) == NULL)
 659                         return ERR;
 660                 GET_COMMAND_SUFFIX();
 661                 if (!isglobal) clear_undo_stack();
 662                 if (*old_filename == '\0' && *fnp != '!')
 663                         strcpy(old_filename, fnp);
 664 #ifdef BACKWARDS
 665                 if (*fnp == '\0' && *old_filename == '\0') {
 666                         sprintf(errmsg, "no current filename");
 667                         return ERR;
 668                 }
 669 #endif
 670                 if ((addr = read_file(*fnp ? fnp : old_filename, second_addr)) < 0)
 671                         return ERR;
 672                 else if (addr && addr != addr_last)
 673                         modified = 1;
 674                 break;
 675         case 's':
 676                 do {
 677                         switch(*ibufp) {
 678                         case '\n':
 679                                 sflags |=SGF;
 680                                 break;
 681                         case 'g':
 682                                 sflags |= SGG;
 683                                 ibufp++;
 684                                 break;
 685                         case 'p':
 686                                 sflags |= SGP;
 687                                 ibufp++;
 688                                 break;
 689                         case 'r':
 690                                 sflags |= SGR;
 691                                 ibufp++;
 692                                 break;
 693                         case '0': case '1': case '2': case '3': case '4':
 694                         case '5': case '6': case '7': case '8': case '9':
 695                                 STRTOL(sgnum, ibufp);
 696                                 sflags |= SGF;
 697                                 sgflag &= ~GSG;         /* override GSG */
 698                                 break;
 699                         default:
 700                                 if (sflags) {
 701                                         sprintf(errmsg, "invalid command suffix");
 702                                         return ERR;
 703                                 }
 704                         }
 705                 } while (sflags && *ibufp != '\n');
 706                 if (sflags && !pat) {
 707                         sprintf(errmsg, "no previous substitution");
 708                         return ERR;
 709                 } else if (sflags & SGG)
 710                         sgnum = 0;              /* override numeric arg */
 711                 if (*ibufp != '\n' && *(ibufp + 1) == '\n') {
 712                         sprintf(errmsg, "invalid pattern delimiter");
 713                         return ERR;
 714                 }
 715                 tpat = pat;
 716                 SPL1();
 717                 if ((!sflags || (sflags & SGR)) &&
 718                     (tpat = get_compiled_pattern()) == NULL) {
 719                         SPL0();
 720                         return ERR;
 721                 } else if (tpat != pat) {
 722                         if (pat) {
 723                                 regfree(pat);
 724                                 free(pat);
 725                         }
 726                         pat = tpat;
 727                         patlock = 1;            /* reserve pattern */
 728                 }
 729                 SPL0();
 730                 if (!sflags && extract_subst_tail(&sgflag, &sgnum) < 0)
 731                         return ERR;
 732                 else if (isglobal)
 733                         sgflag |= GLB;
 734                 else
 735                         sgflag &= ~GLB;
 736                 if (sflags & SGG)
 737                         sgflag ^= GSG;
 738                 if (sflags & SGP)
 739                         sgflag ^= GPR, sgflag &= ~(GLS | GNP);
 740                 do {
 741                         switch(*ibufp) {
 742                         case 'p':
 743                                 sgflag |= GPR, ibufp++;
 744                                 break;
 745                         case 'l':
 746                                 sgflag |= GLS, ibufp++;
 747                                 break;
 748                         case 'n':
 749                                 sgflag |= GNP, ibufp++;
 750                                 break;
 751                         default:
 752                                 n++;
 753                         }
 754                 } while (!n);
 755                 if (check_addr_range(current_addr, current_addr) < 0)
 756                         return ERR;
 757                 GET_COMMAND_SUFFIX();
 758                 if (!isglobal) clear_undo_stack();
 759                 if (search_and_replace(pat, sgflag, sgnum) < 0)
 760                         return ERR;
 761                 break;
 762         case 't':
 763                 if (check_addr_range(current_addr, current_addr) < 0)
 764                         return ERR;
 765                 GET_THIRD_ADDR(addr);
 766                 GET_COMMAND_SUFFIX();
 767                 if (!isglobal) clear_undo_stack();
 768                 if (copy_lines(addr) < 0)
 769                         return ERR;
 770                 break;
 771         case 'u':
 772                 if (addr_cnt > 0) {
 773                         sprintf(errmsg, "unexpected address");
 774                         return ERR;
 775                 }
 776                 GET_COMMAND_SUFFIX();
 777                 if (pop_undo_stack() < 0)
 778                         return ERR;
 779                 break;
 780         case 'w':
 781         case 'W':
 782                 if ((n = *ibufp) == 'q' || n == 'Q') {
 783                         gflag = EOF;
 784                         ibufp++;
 785                 }
 786                 if (!isspace((unsigned char)*ibufp)) {
 787                         sprintf(errmsg, "unexpected command suffix");
 788                         return ERR;
 789                 } else if ((fnp = get_filename()) == NULL)
 790                         return ERR;
 791                 if (addr_cnt == 0 && !addr_last)
 792                         first_addr = second_addr = 0;
 793                 else if (check_addr_range(1, addr_last) < 0)
 794                         return ERR;
 795                 GET_COMMAND_SUFFIX();
 796                 if (*old_filename == '\0' && *fnp != '!')
 797                         strcpy(old_filename, fnp);
 798 #ifdef BACKWARDS
 799                 if (*fnp == '\0' && *old_filename == '\0') {
 800                         sprintf(errmsg, "no current filename");
 801                         return ERR;
 802                 }
 803 #endif
 804                 if ((addr = write_file(*fnp ? fnp : old_filename,
 805                     (c == 'W') ? "a" : "w", first_addr, second_addr)) < 0)
 806                         return ERR;
 807                 else if (addr == addr_last)
 808                         modified = 0;
 809                 else if (modified && !scripted && n == 'q')
 810                         gflag = EMOD;
 811                 break;
 812         case 'x':
 813                 if (addr_cnt > 0) {
 814                         sprintf(errmsg, "unexpected address");
 815                         return ERR;
 816                 }
 817                 GET_COMMAND_SUFFIX();
 818 #ifdef DES
 819                 des = get_keyword();
 820 #else
 821                 sprintf(errmsg, "crypt unavailable");
 822                 return ERR;
 823 #endif
 824                 break;
 825         case 'z':
 826 #ifdef BACKWARDS
 827                 if (check_addr_range(first_addr = 1, current_addr + 1) < 0)
 828 #else
 829                 if (check_addr_range(first_addr = 1, current_addr + !isglobal) < 0)
 830 #endif
 831                         return ERR;
 832                 else if ('0' < *ibufp && *ibufp <= '9')
 833                         STRTOL(rows, ibufp);
 834                 GET_COMMAND_SUFFIX();
 835                 if (display_lines(second_addr, min(addr_last,
 836                     second_addr + rows), gflag) < 0)
 837                         return ERR;
 838                 gflag = 0;
 839                 break;
 840         case '=':
 841                 GET_COMMAND_SUFFIX();
 842                 printf("%ld\n", addr_cnt ? second_addr : addr_last);
 843                 break;
 844         case '!':
 845                 if (addr_cnt > 0) {
 846                         sprintf(errmsg, "unexpected address");
 847                         return ERR;
 848                 } else if ((sflags = get_shell_command()) < 0)
 849                         return ERR;
 850                 GET_COMMAND_SUFFIX();
 851                 if (sflags) printf("%s\n", shcmd + 1);
 852                 system(shcmd + 1);
 853                 if (!scripted) printf("!\n");
 854                 break;
 855         case '\n':
 856 #ifdef BACKWARDS
 857                 if (check_addr_range(first_addr = 1, current_addr + 1) < 0
 858 #else
 859                 if (check_addr_range(first_addr = 1, current_addr + !isglobal) < 0
 860 #endif
 861                  || display_lines(second_addr, second_addr, 0) < 0)
 862                         return ERR;
 863                 break;
 864         default:
 865                 sprintf(errmsg, "unknown command");
 866                 return ERR;
 867         }
 868         return gflag;
 869 }
 870
 871
 872 /* check_addr_range: return status of address range check */
 873 int
 874 check_addr_range(long n, long m)
 875 {
 876         if (addr_cnt == 0) {
 877                 first_addr = n;
 878                 second_addr = m;
 879         }
 880         if (first_addr > second_addr || 1 > first_addr ||
 881             second_addr > addr_last) {
 882                 sprintf(errmsg, "invalid address");
 883                 return ERR;
 884         }
 885         return 0;
 886 }
 887
 888
 889 /* get_matching_node_addr: return the address of the next line matching a
 890    pattern in a given direction.  wrap around begin/end of editor buffer if
 891    necessary */
 892 long
 893 get_matching_node_addr(pattern_t *pat, int dir)
 894 {
 895         char *s;
 896         long n = current_addr;
 897         line_t *lp;
 898
 899         if (!pat) return ERR;
 900         do {
 901                if ((n = dir ? INC_MOD(n, addr_last) : DEC_MOD(n, addr_last))) {
 902                         lp = get_addressed_line_node(n);
 903                         if ((s = get_sbuf_line(lp)) == NULL)
 904                                 return ERR;
 905                         if (isbinary)
 906                                 NUL_TO_NEWLINE(s, lp->len);
 907                         if (!regexec(pat, s, 0, NULL, 0))
 908                                 return n;
 909                }
 910         } while (n != current_addr);
 911         sprintf(errmsg, "no match");
 912         return  ERR;
 913 }
 914
 915
 916 /* get_filename: return pointer to copy of filename in the command buffer */
 917 char *
 918 get_filename(void)
 919 {
 920         static char *file = NULL;
 921         static int filesz = 0;
 922
 923         int n;
 924
 925         if (*ibufp != '\n') {
 926                 SKIP_BLANKS();
 927                 if (*ibufp == '\n') {
 928                         sprintf(errmsg, "invalid filename");
 929                         return NULL;
 930                 } else if ((ibufp = get_extended_line(&n, 1)) == NULL)
 931                         return NULL;
 932                 else if (*ibufp == '!') {
 933                         ibufp++;
 934                         if ((n = get_shell_command()) < 0)
 935                                 return NULL;
 936                         if (n)
 937                                 printf("%s\n", shcmd + 1);
 938                         return shcmd;
 939                 } else if (n > PATH_MAX - 1) {
 940                         sprintf(errmsg, "filename too long");
 941                         return  NULL;
 942                 }
 943         }
 944 #ifndef BACKWARDS
 945         else if (*old_filename == '\0') {
 946                 sprintf(errmsg, "no current filename");
 947                 return  NULL;
 948         }
 949 #endif
 950         REALLOC(file, filesz, PATH_MAX, NULL);
 951         for (n = 0; *ibufp != '\n';)
 952                 file[n++] = *ibufp++;
 953         file[n] = '\0';
 954         return is_legal_filename(file) ? file : NULL;
 955 }
 956
 957
 958 /* get_shell_command: read a shell command from stdin; return substitution
 959    status */
 960 int
 961 get_shell_command(void)
 962 {
 963         static char *buf = NULL;
 964         static int n = 0;
 965
 966         char *s;                        /* substitution char pointer */
 967         int i = 0;
 968         int j = 0;
 969
 970         if (red) {
 971                 sprintf(errmsg, "shell access restricted");
 972                 return ERR;
 973         } else if ((s = ibufp = get_extended_line(&j, 1)) == NULL)
 974                 return ERR;
 975         REALLOC(buf, n, j + 1, ERR);
 976         buf[i++] = '!';                 /* prefix command w/ bang */
 977         while (*ibufp != '\n')
 978                 switch (*ibufp) {
 979                 default:
 980                         REALLOC(buf, n, i + 2, ERR);
 981                         buf[i++] = *ibufp;
 982                         if (*ibufp++ == '\\')
 983                                 buf[i++] = *ibufp++;
 984                         break;
 985                 case '!':
 986                         if (s != ibufp) {
 987                                 REALLOC(buf, n, i + 1, ERR);
 988                                 buf[i++] = *ibufp++;
 989                         }
 990 #ifdef BACKWARDS
 991                         else if (shcmd == NULL || *(shcmd + 1) == '\0')
 992 #else
 993                         else if (shcmd == NULL)
 994 #endif
 995                         {
 996                                 sprintf(errmsg, "no previous command");
 997                                 return ERR;
 998                         } else {
 999                                 REALLOC(buf, n, i + shcmdi, ERR);
1000                                 for (s = shcmd + 1; s < shcmd + shcmdi;)
1001                                         buf[i++] = *s++;
1002                                 s = ibufp++;
1003                         }
1004                         break;
1005                 case '%':
1006                         if (*old_filename  == '\0') {
1007                                 sprintf(errmsg, "no current filename");
1008                                 return ERR;
1009                         }
1010                         j = strlen(s = strip_escapes(old_filename));
1011                         REALLOC(buf, n, i + j, ERR);
1012                         while (j--)
1013                                 buf[i++] = *s++;
1014                         s = ibufp++;
1015                         break;
1016                 }
1017         REALLOC(shcmd, shcmdsz, i + 1, ERR);
1018         memcpy(shcmd, buf, i);
1019         shcmd[shcmdi = i] = '\0';
1020         return *s == '!' || *s == '%';
1021 }
1022
1023
1024 /* append_lines: insert text from stdin to after line n; stop when either a
1025    single period is read or EOF; return status */
1026 int
1027 append_lines(long n)
1028 {
1029         int l;
1030         char *lp = ibuf;
1031         char *eot;
1032         undo_t *up = NULL;
1033
1034         for (current_addr = n;;) {
1035                 if (!isglobal) {
1036                         if ((l = get_tty_line()) < 0)
1037                                 return ERR;
1038                         else if (l == 0 || ibuf[l - 1] != '\n') {
1039                                 clearerr(stdin);
1040                                 return  l ? EOF : 0;
1041                         }
1042                         lp = ibuf;
1043                 } else if (*(lp = ibufp) == '\0')
1044                         return 0;
1045                 else {
1046                         while (*ibufp++ != '\n')
1047                                 ;
1048                         l = ibufp - lp;
1049                 }
1050                 if (l == 2 && lp[0] == '.' && lp[1] == '\n') {
1051                         return 0;
1052                 }
1053                 eot = lp + l;
1054                 SPL1();
1055                 do {
1056                         if ((lp = put_sbuf_line(lp)) == NULL) {
1057                                 SPL0();
1058                                 return ERR;
1059                         } else if (up)
1060                                 up->t = get_addressed_line_node(current_addr);
1061                         else if ((up = push_undo_stack(UADD, current_addr,
1062                             current_addr)) == NULL) {
1063                                 SPL0();
1064                                 return ERR;
1065                         }
1066                 } while (lp != eot);
1067                 modified = 1;
1068                 SPL0();
1069         }
1070         /* NOTREACHED */
1071 }
1072
1073
1074 /* join_lines: replace a range of lines with the joined text of those lines */
1075 int
1076 join_lines(long from, long to)
1077 {
1078         static char *buf = NULL;
1079         static int n;
1080
1081         char *s;
1082         int size = 0;
1083         line_t *bp, *ep;
1084
1085         ep = get_addressed_line_node(INC_MOD(to, addr_last));
1086         bp = get_addressed_line_node(from);
1087         for (; bp != ep; bp = bp->q_forw) {
1088                 if ((s = get_sbuf_line(bp)) == NULL)
1089                         return ERR;
1090                 REALLOC(buf, n, size + bp->len, ERR);
1091                 memcpy(buf + size, s, bp->len);
1092                 size += bp->len;
1093         }
1094         REALLOC(buf, n, size + 2, ERR);
1095         memcpy(buf + size, "\n", 2);
1096         if (delete_lines(from, to) < 0)
1097                 return ERR;
1098         current_addr = from - 1;
1099         SPL1();
1100         if (put_sbuf_line(buf) == NULL ||
1101             push_undo_stack(UADD, current_addr, current_addr) == NULL) {
1102                 SPL0();
1103                 return ERR;
1104         }
1105         modified = 1;
1106         SPL0();
1107         return 0;
1108 }
1109
1110
1111 /* move_lines: move a range of lines */
1112 int
1113 move_lines(long addr)
1114 {
1115         line_t *b1, *a1, *b2, *a2;
1116         long n = INC_MOD(second_addr, addr_last);
1117         long p = first_addr - 1;
1118         int done = (addr == first_addr - 1 || addr == second_addr);
1119
1120         SPL1();
1121         if (done) {
1122                 a2 = get_addressed_line_node(n);
1123                 b2 = get_addressed_line_node(p);
1124                 current_addr = second_addr;
1125         } else if (push_undo_stack(UMOV, p, n) == NULL ||
1126             push_undo_stack(UMOV, addr, INC_MOD(addr, addr_last)) == NULL) {
1127                 SPL0();
1128                 return ERR;
1129         } else {
1130                 a1 = get_addressed_line_node(n);
1131                 if (addr < first_addr) {
1132                         b1 = get_addressed_line_node(p);
1133                         b2 = get_addressed_line_node(addr);
1134                                         /* this get_addressed_line_node last! */
1135                 } else {
1136                         b2 = get_addressed_line_node(addr);
1137                         b1 = get_addressed_line_node(p);
1138                                         /* this get_addressed_line_node last! */
1139                 }
1140                 a2 = b2->q_forw;
1141                 REQUE(b2, b1->q_forw);
1142                 REQUE(a1->q_back, a2);
1143                 REQUE(b1, a1);
1144                 current_addr = addr + ((addr < first_addr) ?
1145                     second_addr - first_addr + 1 : 0);
1146         }
1147         if (isglobal)
1148                 unset_active_nodes(b2->q_forw, a2);
1149         modified = 1;
1150         SPL0();
1151         return 0;
1152 }
1153
1154
1155 /* copy_lines: copy a range of lines; return status */
1156 int
1157 copy_lines(long addr)
1158 {
1159         line_t *lp, *np = get_addressed_line_node(first_addr);
1160         undo_t *up = NULL;
1161         long n = second_addr - first_addr + 1;
1162         long m = 0;
1163
1164         current_addr = addr;
1165         if (first_addr <= addr && addr < second_addr) {
1166                 n =  addr - first_addr + 1;
1167                 m = second_addr - addr;
1168         }
1169         for (; n > 0; n=m, m=0, np = get_addressed_line_node(current_addr + 1))
1170                 for (; n-- > 0; np = np->q_forw) {
1171                         SPL1();
1172                         if ((lp = dup_line_node(np)) == NULL) {
1173                                 SPL0();
1174                                 return ERR;
1175                         }
1176                         add_line_node(lp);
1177                         if (up)
1178                                 up->t = lp;
1179                         else if ((up = push_undo_stack(UADD, current_addr,
1180                             current_addr)) == NULL) {
1181                                 SPL0();
1182                                 return ERR;
1183                         }
1184                         modified = 1;
1185                         SPL0();
1186                 }
1187         return 0;
1188 }
1189
1190
1191 /* delete_lines: delete a range of lines */
1192 int
1193 delete_lines(long from, long to)
1194 {
1195         line_t *n, *p;
1196
1197         SPL1();
1198         if (push_undo_stack(UDEL, from, to) == NULL) {
1199                 SPL0();
1200                 return ERR;
1201         }
1202         n = get_addressed_line_node(INC_MOD(to, addr_last));
1203         p = get_addressed_line_node(from - 1);
1204                                         /* this get_addressed_line_node last! */
1205         if (isglobal)
1206                 unset_active_nodes(p->q_forw, n);
1207         REQUE(p, n);
1208         addr_last -= to - from + 1;
1209         current_addr = from - 1;
1210         modified = 1;
1211         SPL0();
1212         return 0;
1213 }
1214
1215
1216 /* display_lines: print a range of lines to stdout */
1217 int
1218 display_lines(long from, long to, int gflag)
1219 {
1220         line_t *bp;
1221         line_t *ep;
1222         char *s;
1223
1224         if (!from) {
1225                 sprintf(errmsg, "invalid address");
1226                 return ERR;
1227         }
1228         ep = get_addressed_line_node(INC_MOD(to, addr_last));
1229         bp = get_addressed_line_node(from);
1230         for (; bp != ep; bp = bp->q_forw) {
1231                 if ((s = get_sbuf_line(bp)) == NULL)
1232                         return ERR;
1233                 if (put_tty_line(s, bp->len, current_addr = from++, gflag) < 0)
1234                         return ERR;
1235         }
1236         return 0;
1237 }
1238
1239
1240 #define MAXMARK 26                      /* max number of marks */
1241
1242 line_t  *mark[MAXMARK];                 /* line markers */
1243 int markno;                             /* line marker count */
1244
1245 /* mark_line_node: set a line node mark */
1246 int
1247 mark_line_node(line_t *lp, int n)
1248 {
1249         if (!islower((unsigned char)n)) {
1250                 sprintf(errmsg, "invalid mark character");
1251                 return ERR;
1252         } else if (mark[n - 'a'] == NULL)
1253                 markno++;
1254         mark[n - 'a'] = lp;
1255         return 0;
1256 }
1257
1258
1259 /* get_marked_node_addr: return address of a marked line */
1260 long
1261 get_marked_node_addr(int n)
1262 {
1263         if (!islower((unsigned char)n)) {
1264                 sprintf(errmsg, "invalid mark character");
1265                 return ERR;
1266         }
1267         return get_line_node_addr(mark[n - 'a']);
1268 }
1269
1270
1271 /* unmark_line_node: clear line node mark */
1272 void
1273 unmark_line_node(line_t *lp)
1274 {
1275         int i;
1276
1277         for (i = 0; markno && i < MAXMARK; i++)
1278                 if (mark[i] == lp) {
1279                         mark[i] = NULL;
1280                         markno--;
1281                 }
1282 }
1283
1284
1285 /* dup_line_node: return a pointer to a copy of a line node */
1286 line_t *
1287 dup_line_node(line_t *lp)
1288 {
1289         line_t *np;
1290
1291         if ((np = (line_t *) malloc(sizeof(line_t))) == NULL) {
1292                 fprintf(stderr, "%s\n", strerror(errno));
1293                 sprintf(errmsg, "out of memory");
1294                 return NULL;
1295         }
1296         np->seek = lp->seek;
1297         np->len = lp->len;
1298         return np;
1299 }
1300
1301
1302 /* has_trailing_escape:  return the parity of escapes preceding a character
1303    in a string */
1304 int
1305 has_trailing_escape(char *s, char *t)
1306 {
1307     return (s == t || *(t - 1) != '\\') ? 0 : !has_trailing_escape(s, t - 1);
1308 }
1309
1310
1311 /* strip_escapes: return copy of escaped string of at most length PATH_MAX */
1312 char *
1313 strip_escapes(const char *s)
1314 {
1315         static char *file = NULL;
1316         static int filesz = 0;
1317
1318         int i = 0;
1319
1320         REALLOC(file, filesz, PATH_MAX, NULL);
1321         while (i < filesz - 1   /* Worry about a possible trailing escape */
1322                && (file[i++] = (*s == '\\') ? *++s : *s))
1323                 s++;
1324         return file;
1325 }
1326
1327
1328 void
1329 signal_hup(int signo)
1330 {
1331         if (mutex)
1332                 sigflags |= (1 << (signo - 1));
1333         else
1334                 handle_hup(signo);
1335 }
1336
1337
1338 void
1339 signal_int(int signo)
1340 {
1341         if (mutex)
1342                 sigflags |= (1 << (signo - 1));
1343         else
1344                 handle_int(signo);
1345 }
1346
1347
1348 void
1349 handle_hup(int signo)
1350 {
1351         char *hup = NULL;               /* hup filename */
1352         char *s;
1353         int n;
1354
1355         if (!sigactive)
1356                 quit(1);
1357         sigflags &= ~(1 << (signo - 1));
1358         if (addr_last && write_file("ed.hup", "w", 1, addr_last) < 0 &&
1359             (s = getenv("HOME")) != NULL &&
1360             (n = strlen(s)) + 8 <= PATH_MAX &&  /* "ed.hup" + '/' */
1361             (hup = (char *) malloc(n + 10)) != NULL) {
1362                 strcpy(hup, s);
1363                 if (hup[n - 1] != '/')
1364                         hup[n] = '/', hup[n+1] = '\0';
1365                 strcat(hup, "ed.hup");
1366                 write_file(hup, "w", 1, addr_last);
1367         }
1368         quit(2);
1369 }
1370
1371
1372 void
1373 handle_int(int signo)
1374 {
1375         if (!sigactive)
1376                 quit(1);
1377         sigflags &= ~(1 << (signo - 1));
1378 #ifdef _POSIX_SOURCE
1379         siglongjmp(env, -1);
1380 #else
1381         longjmp(env, -1);
1382 #endif
1383 }
1384
1385
1386 int cols = 72;                          /* wrap column */
1387
1388 void
1389 handle_winch(int signo)
1390 {
1391         int save_errno = errno;
1392
1393         struct winsize ws;              /* window size structure */
1394
1395         sigflags &= ~(1 << (signo - 1));
1396         if (ioctl(0, TIOCGWINSZ, (char *) &ws) >= 0) {
1397                 if (ws.ws_row > 2) rows = ws.ws_row - 2;
1398                 if (ws.ws_col > 8) cols = ws.ws_col - 8;
1399         }
1400         errno = save_errno;
1401 }
1402
1403
1404 /* is_legal_filename: return a legal filename */
1405 int
1406 is_legal_filename(char *s)
1407 {
1408         if (red && (*s == '!' || !strcmp(s, "..") || strchr(s, '/'))) {
1409                 sprintf(errmsg, "shell access restricted");
1410                 return 0;
1411         }
1412         return 1;
1413 }