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