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 1.29 2006/08/17 23:00:33 imp Exp $
  31  * $DragonFly: src/bin/ed/main.c,v 1.9 2007/04/06 23:36:54 pavalos 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] [file]\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         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, red ? "red" : "ed");
 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                 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                                 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                                 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                         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                         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() do {                                    \
 285         if (!first) {                                           \
 286                 errmsg = "invalid address";                     \
 287                 return ERR;                                     \
 288         }                                                       \
 289 } while (0)
 290
 291 /*  next_addr: return the next line address in the command buffer */
 292 long
 293 next_addr(void)
 294 {
 295         const char *hd;
 296         long addr = current_addr;
 297         long n;
 298         int first = 1;
 299         int c;
 300
 301         SKIP_BLANKS();
 302         for (hd = ibufp;; first = 0)
 303                 switch (c = *ibufp) {
 304                 case '+':
 305                 case '\t':
 306                 case ' ':
 307                 case '-':
 308                 case '^':
 309                         ibufp++;
 310                         SKIP_BLANKS();
 311                         if (isdigit((unsigned char)*ibufp)) {
 312                                 STRTOL(n, ibufp);
 313                                 addr += (c == '-' || c == '^') ? -n : n;
 314                         } else if (!isspace((unsigned char)c))
 315                                 addr += (c == '-' || c == '^') ? -1 : 1;
 316                         break;
 317                 case '0': case '1': case '2':
 318                 case '3': case '4': case '5':
 319                 case '6': case '7': case '8': case '9':
 320                         MUST_BE_FIRST();
 321                         STRTOL(addr, ibufp);
 322                         break;
 323                 case '.':
 324                 case '$':
 325                         MUST_BE_FIRST();
 326                         ibufp++;
 327                         addr = (c == '.') ? current_addr : addr_last;
 328                         break;
 329                 case '/':
 330                 case '?':
 331                         MUST_BE_FIRST();
 332                         if ((addr = get_matching_node_addr(
 333                             get_compiled_pattern(), c == '/')) < 0)
 334                                 return ERR;
 335                         else if (c == *ibufp)
 336                                 ibufp++;
 337                         break;
 338                 case '\'':
 339                         MUST_BE_FIRST();
 340                         ibufp++;
 341                         if ((addr = get_marked_node_addr(*ibufp++)) < 0)
 342                                 return ERR;
 343                         break;
 344                 case '%':
 345                 case ',':
 346                 case ';':
 347                         if (first) {
 348                                 ibufp++;
 349                                 addr_cnt++;
 350                                 second_addr = (c == ';') ? current_addr : 1;
 351                                 addr = addr_last;
 352                                 break;
 353                         }
 354                         /* FALLTHROUGH */
 355                 default:
 356                         if (ibufp == hd)
 357                                 return EOF;
 358                         else if (addr < 0 || addr_last < addr) {
 359                                 errmsg = "invalid address";
 360                                 return ERR;
 361                         } else
 362                                 return addr;
 363                 }
 364         /* NOTREACHED */
 365 }
 366
 367
 368 #ifdef BACKWARDS
 369 /* GET_THIRD_ADDR: get a legal address from the command buffer */
 370 #define GET_THIRD_ADDR(addr) \
 371 { \
 372         long ol1, ol2; \
 373 \
 374         ol1 = first_addr, ol2 = second_addr; \
 375         if (extract_addr_range() < 0) \
 376                 return ERR; \
 377         else if (addr_cnt == 0) { \
 378                 errmsg = "destination expected"; \
 379                 return ERR; \
 380         } else if (second_addr < 0 || addr_last < second_addr) { \
 381                 errmsg = "invalid address"; \
 382                 return ERR; \
 383         } \
 384         addr = second_addr; \
 385         first_addr = ol1, second_addr = ol2; \
 386 }
 387 #else   /* BACKWARDS */
 388 /* GET_THIRD_ADDR: get a legal address from the command buffer */
 389 #define GET_THIRD_ADDR(addr) \
 390 { \
 391         long ol1, ol2; \
 392 \
 393         ol1 = first_addr, ol2 = second_addr; \
 394         if (extract_addr_range() < 0) \
 395                 return ERR; \
 396         if (second_addr < 0 || addr_last < second_addr) { \
 397                 errmsg = "invalid address"; \
 398                 return ERR; \
 399         } \
 400         addr = second_addr; \
 401         first_addr = ol1, second_addr = ol2; \
 402 }
 403 #endif
 404
 405
 406 /* GET_COMMAND_SUFFIX: verify the command suffix in the command buffer */
 407 #define GET_COMMAND_SUFFIX() { \
 408         int done = 0; \
 409         do { \
 410                 switch(*ibufp) { \
 411                 case 'p': \
 412                         gflag |= GPR, ibufp++; \
 413                         break; \
 414                 case 'l': \
 415                         gflag |= GLS, ibufp++; \
 416                         break; \
 417                 case 'n': \
 418                         gflag |= GNP, ibufp++; \
 419                         break; \
 420                 default: \
 421                         done++; \
 422                 } \
 423         } while (!done); \
 424         if (*ibufp++ != '\n') { \
 425                 errmsg = "invalid command suffix"; \
 426                 return ERR; \
 427         } \
 428 }
 429
 430
 431 /* sflags */
 432 #define SGG 001         /* complement previous global substitute suffix */
 433 #define SGP 002         /* complement previous print suffix */
 434 #define SGR 004         /* use last regex instead of last pat */
 435 #define SGF 010         /* repeat last substitution */
 436
 437 int patlock = 0;        /* if set, pattern not freed by get_compiled_pattern() */
 438
 439 long rows = 22;         /* scroll length: ws_row - 2 */
 440
 441 /* exec_command: execute the next command in command buffer; return print
 442    request, if any */
 443 int
 444 exec_command(void)
 445 {
 446         static pattern_t *pat = NULL;
 447         static int sgflag = 0;
 448         static long sgnum = 0;
 449
 450         pattern_t *tpat;
 451         char *fnp;
 452         int gflag = 0;
 453         int sflags = 0;
 454         long addr = 0;
 455         int n = 0;
 456         int c;
 457
 458         SKIP_BLANKS();
 459         switch(c = *ibufp++) {
 460         case 'a':
 461                 GET_COMMAND_SUFFIX();
 462                 if (!isglobal) clear_undo_stack();
 463                 if (append_lines(second_addr) < 0)
 464                         return ERR;
 465                 break;
 466         case 'c':
 467                 if (check_addr_range(current_addr, current_addr) < 0)
 468                         return ERR;
 469                 GET_COMMAND_SUFFIX();
 470                 if (!isglobal) clear_undo_stack();
 471                 if (delete_lines(first_addr, second_addr) < 0 ||
 472                     append_lines(current_addr) < 0)
 473                         return ERR;
 474                 break;
 475         case 'd':
 476                 if (check_addr_range(current_addr, current_addr) < 0)
 477                         return ERR;
 478                 GET_COMMAND_SUFFIX();
 479                 if (!isglobal) clear_undo_stack();
 480                 if (delete_lines(first_addr, second_addr) < 0)
 481                         return ERR;
 482                 else if ((addr = INC_MOD(current_addr, addr_last)) != 0)
 483                         current_addr = addr;
 484                 break;
 485         case 'e':
 486                 if (modified && !scripted)
 487                         return EMOD;
 488                 /* FALLTHROUGH */
 489         case 'E':
 490                 if (addr_cnt > 0) {
 491                         errmsg = "unexpected address";
 492                         return ERR;
 493                 } else if (!isspace((unsigned char)*ibufp)) {
 494                         errmsg = "unexpected command suffix";
 495                         return ERR;
 496                 } else if ((fnp = get_filename()) == NULL)
 497                         return ERR;
 498                 GET_COMMAND_SUFFIX();
 499                 if (delete_lines(1, addr_last) < 0)
 500                         return ERR;
 501                 clear_undo_stack();
 502                 if (close_sbuf() < 0)
 503                         return ERR;
 504                 else if (open_sbuf() < 0)
 505                         return FATAL;
 506                 if (*fnp && *fnp != '!') strcpy(old_filename, fnp);
 507 #ifdef BACKWARDS
 508                 if (*fnp == '\0' && *old_filename == '\0') {
 509                         errmsg = "no current filename";
 510                         return ERR;
 511                 }
 512 #endif
 513                 if (read_file(*fnp ? fnp : old_filename, 0) < 0)
 514                         return ERR;
 515                 clear_undo_stack();
 516                 modified = 0;
 517                 u_current_addr = u_addr_last = -1;
 518                 break;
 519         case 'f':
 520                 if (addr_cnt > 0) {
 521                         errmsg = "unexpected address";
 522                         return ERR;
 523                 } else if (!isspace((unsigned char)*ibufp)) {
 524                         errmsg = "unexpected command suffix";
 525                         return ERR;
 526                 } else if ((fnp = get_filename()) == NULL)
 527                         return ERR;
 528                 else if (*fnp == '!') {
 529                         errmsg = "invalid redirection";
 530                         return ERR;
 531                 }
 532                 GET_COMMAND_SUFFIX();
 533                 if (*fnp) strcpy(old_filename, fnp);
 534                 printf("%s\n", strip_escapes(old_filename));
 535                 break;
 536         case 'g':
 537         case 'v':
 538         case 'G':
 539         case 'V':
 540                 if (isglobal) {
 541                         errmsg = "cannot nest global commands";
 542                         return ERR;
 543                 } else if (check_addr_range(1, addr_last) < 0)
 544                         return ERR;
 545                 else if (build_active_list(c == 'g' || c == 'G') < 0)
 546                         return ERR;
 547                 else if ((n = (c == 'G' || c == 'V')))
 548                         GET_COMMAND_SUFFIX();
 549                 isglobal++;
 550                 if (exec_global(n, gflag) < 0)
 551                         return ERR;
 552                 break;
 553         case 'h':
 554                 if (addr_cnt > 0) {
 555                         errmsg = "unexpected address";
 556                         return ERR;
 557                 }
 558                 GET_COMMAND_SUFFIX();
 559                 if (*errmsg) fprintf(stderr, "%s\n", errmsg);
 560                 break;
 561         case 'H':
 562                 if (addr_cnt > 0) {
 563                         errmsg = "unexpected address";
 564                         return ERR;
 565                 }
 566                 GET_COMMAND_SUFFIX();
 567                 if ((garrulous = 1 - garrulous) && *errmsg)
 568                         fprintf(stderr, "%s\n", errmsg);
 569                 break;
 570         case 'i':
 571                 if (second_addr == 0) {
 572                         errmsg = "invalid address";
 573                         return ERR;
 574                 }
 575                 GET_COMMAND_SUFFIX();
 576                 if (!isglobal) clear_undo_stack();
 577                 if (append_lines(second_addr - 1) < 0)
 578                         return ERR;
 579                 break;
 580         case 'j':
 581                 if (check_addr_range(current_addr, current_addr + 1) < 0)
 582                         return ERR;
 583                 GET_COMMAND_SUFFIX();
 584                 if (!isglobal) clear_undo_stack();
 585                 if (first_addr != second_addr &&
 586                     join_lines(first_addr, second_addr) < 0)
 587                         return ERR;
 588                 break;
 589         case 'k':
 590                 c = *ibufp++;
 591                 if (second_addr == 0) {
 592                         errmsg = "invalid address";
 593                         return ERR;
 594                 }
 595                 GET_COMMAND_SUFFIX();
 596                 if (mark_line_node(get_addressed_line_node(second_addr), c) < 0)
 597                         return ERR;
 598                 break;
 599         case 'l':
 600                 if (check_addr_range(current_addr, current_addr) < 0)
 601                         return ERR;
 602                 GET_COMMAND_SUFFIX();
 603                 if (display_lines(first_addr, second_addr, gflag | GLS) < 0)
 604                         return ERR;
 605                 gflag = 0;
 606                 break;
 607         case 'm':
 608                 if (check_addr_range(current_addr, current_addr) < 0)
 609                         return ERR;
 610                 GET_THIRD_ADDR(addr);
 611                 if (first_addr <= addr && addr < second_addr) {
 612                         errmsg = "invalid destination";
 613                         return ERR;
 614                 }
 615                 GET_COMMAND_SUFFIX();
 616                 if (!isglobal) clear_undo_stack();
 617                 if (move_lines(addr) < 0)
 618                         return ERR;
 619                 break;
 620         case 'n':
 621                 if (check_addr_range(current_addr, current_addr) < 0)
 622                         return ERR;
 623                 GET_COMMAND_SUFFIX();
 624                 if (display_lines(first_addr, second_addr, gflag | GNP) < 0)
 625                         return ERR;
 626                 gflag = 0;
 627                 break;
 628         case 'p':
 629                 if (check_addr_range(current_addr, current_addr) < 0)
 630                         return ERR;
 631                 GET_COMMAND_SUFFIX();
 632                 if (display_lines(first_addr, second_addr, gflag | GPR) < 0)
 633                         return ERR;
 634                 gflag = 0;
 635                 break;
 636         case 'P':
 637                 if (addr_cnt > 0) {
 638                         errmsg = "unexpected address";
 639                         return ERR;
 640                 }
 641                 GET_COMMAND_SUFFIX();
 642                 prompt = prompt ? NULL : optarg ? optarg : dps;
 643                 break;
 644         case 'q':
 645         case 'Q':
 646                 if (addr_cnt > 0) {
 647                         errmsg = "unexpected address";
 648                         return ERR;
 649                 }
 650                 GET_COMMAND_SUFFIX();
 651                 gflag =  (modified && !scripted && c == 'q') ? EMOD : EOF;
 652                 break;
 653         case 'r':
 654                 if (!isspace((unsigned char)*ibufp)) {
 655                         errmsg = "unexpected command suffix";
 656                         return ERR;
 657                 } else if (addr_cnt == 0)
 658                         second_addr = addr_last;
 659                 if ((fnp = get_filename()) == NULL)
 660                         return ERR;
 661                 GET_COMMAND_SUFFIX();
 662                 if (!isglobal) clear_undo_stack();
 663                 if (*old_filename == '\0' && *fnp != '!')
 664                         strcpy(old_filename, fnp);
 665 #ifdef BACKWARDS
 666                 if (*fnp == '\0' && *old_filename == '\0') {
 667                         errmsg = "no current filename";
 668                         return ERR;
 669                 }
 670 #endif
 671                 if ((addr = read_file(*fnp ? fnp : old_filename, second_addr)) < 0)
 672                         return ERR;
 673                 else if (addr && addr != addr_last)
 674                         modified = 1;
 675                 break;
 676         case 's':
 677                 do {
 678                         switch(*ibufp) {
 679                         case '\n':
 680                                 sflags |=SGF;
 681                                 break;
 682                         case 'g':
 683                                 sflags |= SGG;
 684                                 ibufp++;
 685                                 break;
 686                         case 'p':
 687                                 sflags |= SGP;
 688                                 ibufp++;
 689                                 break;
 690                         case 'r':
 691                                 sflags |= SGR;
 692                                 ibufp++;
 693                                 break;
 694                         case '0': case '1': case '2': case '3': case '4':
 695                         case '5': case '6': case '7': case '8': case '9':
 696                                 STRTOL(sgnum, ibufp);
 697                                 sflags |= SGF;
 698                                 sgflag &= ~GSG;         /* override GSG */
 699                                 break;
 700                         default:
 701                                 if (sflags) {
 702                                         errmsg = "invalid command suffix";
 703                                         return ERR;
 704                                 }
 705                         }
 706                 } while (sflags && *ibufp != '\n');
 707                 if (sflags && !pat) {
 708                         errmsg = "no previous substitution";
 709                         return ERR;
 710                 } else if (sflags & SGG)
 711                         sgnum = 0;              /* override numeric arg */
 712                 if (*ibufp != '\n' && *(ibufp + 1) == '\n') {
 713                         errmsg = "invalid pattern delimiter";
 714                         return ERR;
 715                 }
 716                 tpat = pat;
 717                 SPL1();
 718                 if ((!sflags || (sflags & SGR)) &&
 719                     (tpat = get_compiled_pattern()) == NULL) {
 720                         SPL0();
 721                         return ERR;
 722                 } else if (tpat != pat) {
 723                         if (pat) {
 724                                 regfree(pat);
 725                                 free(pat);
 726                         }
 727                         pat = tpat;
 728                         patlock = 1;            /* reserve pattern */
 729                 }
 730                 SPL0();
 731                 if (!sflags && extract_subst_tail(&sgflag, &sgnum) < 0)
 732                         return ERR;
 733                 else if (isglobal)
 734                         sgflag |= GLB;
 735                 else
 736                         sgflag &= ~GLB;
 737                 if (sflags & SGG)
 738                         sgflag ^= GSG;
 739                 if (sflags & SGP)
 740                         sgflag ^= GPR, sgflag &= ~(GLS | GNP);
 741                 do {
 742                         switch(*ibufp) {
 743                         case 'p':
 744                                 sgflag |= GPR, ibufp++;
 745                                 break;
 746                         case 'l':
 747                                 sgflag |= GLS, ibufp++;
 748                                 break;
 749                         case 'n':
 750                                 sgflag |= GNP, ibufp++;
 751                                 break;
 752                         default:
 753                                 n++;
 754                         }
 755                 } while (!n);
 756                 if (check_addr_range(current_addr, current_addr) < 0)
 757                         return ERR;
 758                 GET_COMMAND_SUFFIX();
 759                 if (!isglobal) clear_undo_stack();
 760                 if (search_and_replace(pat, sgflag, sgnum) < 0)
 761                         return ERR;
 762                 break;
 763         case 't':
 764                 if (check_addr_range(current_addr, current_addr) < 0)
 765                         return ERR;
 766                 GET_THIRD_ADDR(addr);
 767                 GET_COMMAND_SUFFIX();
 768                 if (!isglobal) clear_undo_stack();
 769                 if (copy_lines(addr) < 0)
 770                         return ERR;
 771                 break;
 772         case 'u':
 773                 if (addr_cnt > 0) {
 774                         errmsg = "unexpected address";
 775                         return ERR;
 776                 }
 777                 GET_COMMAND_SUFFIX();
 778                 if (pop_undo_stack() < 0)
 779                         return ERR;
 780                 break;
 781         case 'w':
 782         case 'W':
 783                 if ((n = *ibufp) == 'q' || n == 'Q') {
 784                         gflag = EOF;
 785                         ibufp++;
 786                 }
 787                 if (!isspace((unsigned char)*ibufp)) {
 788                         errmsg = "unexpected command suffix";
 789                         return ERR;
 790                 } else if ((fnp = get_filename()) == NULL)
 791                         return ERR;
 792                 if (addr_cnt == 0 && !addr_last)
 793                         first_addr = second_addr = 0;
 794                 else if (check_addr_range(1, addr_last) < 0)
 795                         return ERR;
 796                 GET_COMMAND_SUFFIX();
 797                 if (*old_filename == '\0' && *fnp != '!')
 798                         strcpy(old_filename, fnp);
 799 #ifdef BACKWARDS
 800                 if (*fnp == '\0' && *old_filename == '\0') {
 801                         errmsg = "no current filename";
 802                         return ERR;
 803                 }
 804 #endif
 805                 if ((addr = write_file(*fnp ? fnp : old_filename,
 806                     (c == 'W') ? "a" : "w", first_addr, second_addr)) < 0)
 807                         return ERR;
 808                 else if (addr == addr_last)
 809                         modified = 0;
 810                 else if (modified && !scripted && n == 'q')
 811                         gflag = EMOD;
 812                 break;
 813         case 'x':
 814                 if (addr_cnt > 0) {
 815                         errmsg = "unexpected address";
 816                         return ERR;
 817                 }
 818                 GET_COMMAND_SUFFIX();
 819 #ifdef DES
 820                 des = get_keyword();
 821                 break;
 822 #else
 823                 errmsg = "crypt unavailable";
 824                 return ERR;
 825 #endif
 826         case 'z':
 827 #ifdef BACKWARDS
 828                 if (check_addr_range(first_addr = 1, current_addr + 1) < 0)
 829 #else
 830                 if (check_addr_range(first_addr = 1, current_addr + !isglobal) < 0)
 831 #endif
 832                         return ERR;
 833                 else if ('0' < *ibufp && *ibufp <= '9')
 834                         STRTOL(rows, ibufp);
 835                 GET_COMMAND_SUFFIX();
 836                 if (display_lines(second_addr, min(addr_last,
 837                     second_addr + rows), gflag) < 0)
 838                         return ERR;
 839                 gflag = 0;
 840                 break;
 841         case '=':
 842                 GET_COMMAND_SUFFIX();
 843                 printf("%ld\n", addr_cnt ? second_addr : addr_last);
 844                 break;
 845         case '!':
 846                 if (addr_cnt > 0) {
 847                         errmsg = "unexpected address";
 848                         return ERR;
 849                 } else if ((sflags = get_shell_command()) < 0)
 850                         return ERR;
 851                 GET_COMMAND_SUFFIX();
 852                 if (sflags) printf("%s\n", shcmd + 1);
 853                 system(shcmd + 1);
 854                 if (!scripted) printf("!\n");
 855                 break;
 856         case '\n':
 857 #ifdef BACKWARDS
 858                 if (check_addr_range(first_addr = 1, current_addr + 1) < 0
 859 #else
 860                 if (check_addr_range(first_addr = 1, current_addr + !isglobal) < 0
 861 #endif
 862                  || display_lines(second_addr, second_addr, 0) < 0)
 863                         return ERR;
 864                 break;
 865         default:
 866                 errmsg = "unknown command";
 867                 return ERR;
 868         }
 869         return gflag;
 870 }
 871
 872
 873 /* check_addr_range: return status of address range check */
 874 int
 875 check_addr_range(long n, long m)
 876 {
 877         if (addr_cnt == 0) {
 878                 first_addr = n;
 879                 second_addr = m;
 880         }
 881         if (first_addr > second_addr || 1 > first_addr ||
 882             second_addr > addr_last) {
 883                 errmsg = "invalid address";
 884                 return ERR;
 885         }
 886         return 0;
 887 }
 888
 889
 890 /* get_matching_node_addr: return the address of the next line matching a
 891    pattern in a given direction.  wrap around begin/end of editor buffer if
 892    necessary */
 893 long
 894 get_matching_node_addr(pattern_t *pat, int dir)
 895 {
 896         char *s;
 897         long n = current_addr;
 898         line_t *lp;
 899
 900         if (!pat) return ERR;
 901         do {
 902                if ((n = dir ? INC_MOD(n, addr_last) : DEC_MOD(n, addr_last))) {
 903                         lp = get_addressed_line_node(n);
 904                         if ((s = get_sbuf_line(lp)) == NULL)
 905                                 return ERR;
 906                         if (isbinary)
 907                                 NUL_TO_NEWLINE(s, lp->len);
 908                         if (!regexec(pat, s, 0, NULL, 0))
 909                                 return n;
 910                }
 911         } while (n != current_addr);
 912         errmsg = "no match";
 913         return  ERR;
 914 }
 915
 916
 917 /* get_filename: return pointer to copy of filename in the command buffer */
 918 char *
 919 get_filename(void)
 920 {
 921         static char *file = NULL;
 922         static int filesz = 0;
 923
 924         int n;
 925
 926         if (*ibufp != '\n') {
 927                 SKIP_BLANKS();
 928                 if (*ibufp == '\n') {
 929                         errmsg = "invalid filename";
 930                         return NULL;
 931                 } else if ((ibufp = get_extended_line(&n, 1)) == NULL)
 932                         return NULL;
 933                 else if (*ibufp == '!') {
 934                         ibufp++;
 935                         if ((n = get_shell_command()) < 0)
 936                                 return NULL;
 937                         if (n)
 938                                 printf("%s\n", shcmd + 1);
 939                         return shcmd;
 940                 } else if (n > PATH_MAX - 1) {
 941                         errmsg = "filename too long";
 942                         return  NULL;
 943                 }
 944         }
 945 #ifndef BACKWARDS
 946         else if (*old_filename == '\0') {
 947                 errmsg = "no current filename";
 948                 return  NULL;
 949         }
 950 #endif
 951         REALLOC(file, filesz, PATH_MAX, NULL);
 952         for (n = 0; *ibufp != '\n';)
 953                 file[n++] = *ibufp++;
 954         file[n] = '\0';
 955         return is_legal_filename(file) ? file : NULL;
 956 }
 957
 958
 959 /* get_shell_command: read a shell command from stdin; return substitution
 960    status */
 961 int
 962 get_shell_command(void)
 963 {
 964         static char *buf = NULL;
 965         static int n = 0;
 966
 967         char *s;                        /* substitution char pointer */
 968         int i = 0;
 969         int j = 0;
 970
 971         if (red) {
 972                 errmsg = "shell access restricted";
 973                 return ERR;
 974         } else if ((s = ibufp = get_extended_line(&j, 1)) == NULL)
 975                 return ERR;
 976         REALLOC(buf, n, j + 1, ERR);
 977         buf[i++] = '!';                 /* prefix command w/ bang */
 978         while (*ibufp != '\n')
 979                 switch (*ibufp) {
 980                 default:
 981                         REALLOC(buf, n, i + 2, ERR);
 982                         buf[i++] = *ibufp;
 983                         if (*ibufp++ == '\\')
 984                                 buf[i++] = *ibufp++;
 985                         break;
 986                 case '!':
 987                         if (s != ibufp) {
 988                                 REALLOC(buf, n, i + 1, ERR);
 989                                 buf[i++] = *ibufp++;
 990                         }
 991 #ifdef BACKWARDS
 992                         else if (shcmd == NULL || *(shcmd + 1) == '\0')
 993 #else
 994                         else if (shcmd == NULL)
 995 #endif
 996                         {
 997                                 errmsg = "no previous command";
 998                                 return ERR;
 999                         } else {
1000                                 REALLOC(buf, n, i + shcmdi, ERR);
1001                                 for (s = shcmd + 1; s < shcmd + shcmdi;)
1002                                         buf[i++] = *s++;
1003                                 s = ibufp++;
1004                         }
1005                         break;
1006                 case '%':
1007                         if (*old_filename  == '\0') {
1008                                 errmsg = "no current filename";
1009                                 return ERR;
1010                         }
1011                         j = strlen(s = strip_escapes(old_filename));
1012                         REALLOC(buf, n, i + j, ERR);
1013                         while (j--)
1014                                 buf[i++] = *s++;
1015                         s = ibufp++;
1016                         break;
1017                 }
1018         REALLOC(shcmd, shcmdsz, i + 1, ERR);
1019         memcpy(shcmd, buf, i);
1020         shcmd[shcmdi = i] = '\0';
1021         return *s == '!' || *s == '%';
1022 }
1023
1024
1025 /* append_lines: insert text from stdin to after line n; stop when either a
1026    single period is read or EOF; return status */
1027 int
1028 append_lines(long n)
1029 {
1030         int l;
1031         const char *lp = ibuf;
1032         const char *eot;
1033         undo_t *up = NULL;
1034
1035         for (current_addr = n;;) {
1036                 if (!isglobal) {
1037                         if ((l = get_tty_line()) < 0)
1038                                 return ERR;
1039                         else if (l == 0 || ibuf[l - 1] != '\n') {
1040                                 clearerr(stdin);
1041                                 return  l ? EOF : 0;
1042                         }
1043                         lp = ibuf;
1044                 } else if (*(lp = ibufp) == '\0')
1045                         return 0;
1046                 else {
1047                         while (*ibufp++ != '\n')
1048                                 ;
1049                         l = ibufp - lp;
1050                 }
1051                 if (l == 2 && lp[0] == '.' && lp[1] == '\n') {
1052                         return 0;
1053                 }
1054                 eot = lp + l;
1055                 SPL1();
1056                 do {
1057                         if ((lp = put_sbuf_line(lp)) == NULL) {
1058                                 SPL0();
1059                                 return ERR;
1060                         } else if (up)
1061                                 up->t = get_addressed_line_node(current_addr);
1062                         else if ((up = push_undo_stack(UADD, current_addr,
1063                             current_addr)) == NULL) {
1064                                 SPL0();
1065                                 return ERR;
1066                         }
1067                 } while (lp != eot);
1068                 modified = 1;
1069                 SPL0();
1070         }
1071         /* NOTREACHED */
1072 }
1073
1074
1075 /* join_lines: replace a range of lines with the joined text of those lines */
1076 int
1077 join_lines(long from, long to)
1078 {
1079         static char *buf = NULL;
1080         static int n;
1081
1082         char *s;
1083         int size = 0;
1084         line_t *bp, *ep;
1085
1086         ep = get_addressed_line_node(INC_MOD(to, addr_last));
1087         bp = get_addressed_line_node(from);
1088         for (; bp != ep; bp = bp->q_forw) {
1089                 if ((s = get_sbuf_line(bp)) == NULL)
1090                         return ERR;
1091                 REALLOC(buf, n, size + bp->len, ERR);
1092                 memcpy(buf + size, s, bp->len);
1093                 size += bp->len;
1094         }
1095         REALLOC(buf, n, size + 2, ERR);
1096         memcpy(buf + size, "\n", 2);
1097         if (delete_lines(from, to) < 0)
1098                 return ERR;
1099         current_addr = from - 1;
1100         SPL1();
1101         if (put_sbuf_line(buf) == NULL ||
1102             push_undo_stack(UADD, current_addr, current_addr) == NULL) {
1103                 SPL0();
1104                 return ERR;
1105         }
1106         modified = 1;
1107         SPL0();
1108         return 0;
1109 }
1110
1111
1112 /* move_lines: move a range of lines */
1113 int
1114 move_lines(long addr)
1115 {
1116         line_t *b1, *a1, *b2, *a2;
1117         long n = INC_MOD(second_addr, addr_last);
1118         long p = first_addr - 1;
1119         int done = (addr == first_addr - 1 || addr == second_addr);
1120
1121         SPL1();
1122         if (done) {
1123                 a2 = get_addressed_line_node(n);
1124                 b2 = get_addressed_line_node(p);
1125                 current_addr = second_addr;
1126         } else if (push_undo_stack(UMOV, p, n) == NULL ||
1127             push_undo_stack(UMOV, addr, INC_MOD(addr, addr_last)) == NULL) {
1128                 SPL0();
1129                 return ERR;
1130         } else {
1131                 a1 = get_addressed_line_node(n);
1132                 if (addr < first_addr) {
1133                         b1 = get_addressed_line_node(p);
1134                         b2 = get_addressed_line_node(addr);
1135                                         /* this get_addressed_line_node last! */
1136                 } else {
1137                         b2 = get_addressed_line_node(addr);
1138                         b1 = get_addressed_line_node(p);
1139                                         /* this get_addressed_line_node last! */
1140                 }
1141                 a2 = b2->q_forw;
1142                 REQUE(b2, b1->q_forw);
1143                 REQUE(a1->q_back, a2);
1144                 REQUE(b1, a1);
1145                 current_addr = addr + ((addr < first_addr) ?
1146                     second_addr - first_addr + 1 : 0);
1147         }
1148         if (isglobal)
1149                 unset_active_nodes(b2->q_forw, a2);
1150         modified = 1;
1151         SPL0();
1152         return 0;
1153 }
1154
1155
1156 /* copy_lines: copy a range of lines; return status */
1157 int
1158 copy_lines(long addr)
1159 {
1160         line_t *lp, *np = get_addressed_line_node(first_addr);
1161         undo_t *up = NULL;
1162         long n = second_addr - first_addr + 1;
1163         long m = 0;
1164
1165         current_addr = addr;
1166         if (first_addr <= addr && addr < second_addr) {
1167                 n =  addr - first_addr + 1;
1168                 m = second_addr - addr;
1169         }
1170         for (; n > 0; n=m, m=0, np = get_addressed_line_node(current_addr + 1))
1171                 for (; n-- > 0; np = np->q_forw) {
1172                         SPL1();
1173                         if ((lp = dup_line_node(np)) == NULL) {
1174                                 SPL0();
1175                                 return ERR;
1176                         }
1177                         add_line_node(lp);
1178                         if (up)
1179                                 up->t = lp;
1180                         else if ((up = push_undo_stack(UADD, current_addr,
1181                             current_addr)) == NULL) {
1182                                 SPL0();
1183                                 return ERR;
1184                         }
1185                         modified = 1;
1186                         SPL0();
1187                 }
1188         return 0;
1189 }
1190
1191
1192 /* delete_lines: delete a range of lines */
1193 int
1194 delete_lines(long from, long to)
1195 {
1196         line_t *n, *p;
1197
1198         SPL1();
1199         if (push_undo_stack(UDEL, from, to) == NULL) {
1200                 SPL0();
1201                 return ERR;
1202         }
1203         n = get_addressed_line_node(INC_MOD(to, addr_last));
1204         p = get_addressed_line_node(from - 1);
1205                                         /* this get_addressed_line_node last! */
1206         if (isglobal)
1207                 unset_active_nodes(p->q_forw, n);
1208         REQUE(p, n);
1209         addr_last -= to - from + 1;
1210         current_addr = from - 1;
1211         modified = 1;
1212         SPL0();
1213         return 0;
1214 }
1215
1216
1217 /* display_lines: print a range of lines to stdout */
1218 int
1219 display_lines(long from, long to, int gflag)
1220 {
1221         line_t *bp;
1222         line_t *ep;
1223         char *s;
1224
1225         if (!from) {
1226                 errmsg = "invalid address";
1227                 return ERR;
1228         }
1229         ep = get_addressed_line_node(INC_MOD(to, addr_last));
1230         bp = get_addressed_line_node(from);
1231         for (; bp != ep; bp = bp->q_forw) {
1232                 if ((s = get_sbuf_line(bp)) == NULL)
1233                         return ERR;
1234                 if (put_tty_line(s, bp->len, current_addr = from++, gflag) < 0)
1235                         return ERR;
1236         }
1237         return 0;
1238 }
1239
1240
1241 #define MAXMARK 26                      /* max number of marks */
1242
1243 line_t  *mark[MAXMARK];                 /* line markers */
1244 int markno;                             /* line marker count */
1245
1246 /* mark_line_node: set a line node mark */
1247 int
1248 mark_line_node(line_t *lp, int n)
1249 {
1250         if (!islower((unsigned char)n)) {
1251                 errmsg = "invalid mark character";
1252                 return ERR;
1253         } else if (mark[n - 'a'] == NULL)
1254                 markno++;
1255         mark[n - 'a'] = lp;
1256         return 0;
1257 }
1258
1259
1260 /* get_marked_node_addr: return address of a marked line */
1261 long
1262 get_marked_node_addr(int n)
1263 {
1264         if (!islower((unsigned char)n)) {
1265                 errmsg = "invalid mark character";
1266                 return ERR;
1267         }
1268         return get_line_node_addr(mark[n - 'a']);
1269 }
1270
1271
1272 /* unmark_line_node: clear line node mark */
1273 void
1274 unmark_line_node(line_t *lp)
1275 {
1276         int i;
1277
1278         for (i = 0; markno && i < MAXMARK; i++)
1279                 if (mark[i] == lp) {
1280                         mark[i] = NULL;
1281                         markno--;
1282                 }
1283 }
1284
1285
1286 /* dup_line_node: return a pointer to a copy of a line node */
1287 line_t *
1288 dup_line_node(line_t *lp)
1289 {
1290         line_t *np;
1291
1292         if ((np = (line_t *) malloc(sizeof(line_t))) == NULL) {
1293                 fprintf(stderr, "%s\n", strerror(errno));
1294                 errmsg = "out of memory";
1295                 return NULL;
1296         }
1297         np->seek = lp->seek;
1298         np->len = lp->len;
1299         return np;
1300 }
1301
1302
1303 /* has_trailing_escape:  return the parity of escapes preceding a character
1304    in a string */
1305 int
1306 has_trailing_escape(char *s, char *t)
1307 {
1308     return (s == t || *(t - 1) != '\\') ? 0 : !has_trailing_escape(s, t - 1);
1309 }
1310
1311
1312 /* strip_escapes: return copy of escaped string of at most length PATH_MAX */
1313 char *
1314 strip_escapes(const char *s)
1315 {
1316         static char *file = NULL;
1317         static int filesz = 0;
1318
1319         int i = 0;
1320
1321         REALLOC(file, filesz, PATH_MAX, NULL);
1322         while (i < filesz - 1   /* Worry about a possible trailing escape */
1323                && (file[i++] = (*s == '\\') ? *++s : *s))
1324                 s++;
1325         return file;
1326 }
1327
1328
1329 void
1330 signal_hup(int signo)
1331 {
1332         if (mutex)
1333                 sigflags |= (1 << (signo - 1));
1334         else
1335                 handle_hup(signo);
1336 }
1337
1338
1339 void
1340 signal_int(int signo)
1341 {
1342         if (mutex)
1343                 sigflags |= (1 << (signo - 1));
1344         else
1345                 handle_int(signo);
1346 }
1347
1348
1349 void
1350 handle_hup(int signo)
1351 {
1352         char *hup = NULL;               /* hup filename */
1353         char *s;
1354         char ed_hup[] = "ed.hup";
1355         int n;
1356
1357         if (!sigactive)
1358                 quit(1);
1359         sigflags &= ~(1 << (signo - 1));
1360         if (addr_last && write_file(ed_hup, "w", 1, addr_last) < 0 &&
1361             (s = getenv("HOME")) != NULL &&
1362             (n = strlen(s)) + 8 <= PATH_MAX &&  /* "ed.hup" + '/' */
1363             (hup = (char *) malloc(n + 10)) != NULL) {
1364                 strcpy(hup, s);
1365                 if (hup[n - 1] != '/')
1366                         hup[n] = '/', hup[n+1] = '\0';
1367                 strcat(hup, "ed.hup");
1368                 write_file(hup, "w", 1, addr_last);
1369         }
1370         quit(2);
1371 }
1372
1373
1374 void
1375 handle_int(int signo)
1376 {
1377         if (!sigactive)
1378                 quit(1);
1379         sigflags &= ~(1 << (signo - 1));
1380 #ifdef _POSIX_SOURCE
1381         siglongjmp(env, -1);
1382 #else
1383         longjmp(env, -1);
1384 #endif
1385 }
1386
1387
1388 int cols = 72;                          /* wrap column */
1389
1390 void
1391 handle_winch(int signo)
1392 {
1393         int save_errno = errno;
1394
1395         struct winsize ws;              /* window size structure */
1396
1397         sigflags &= ~(1 << (signo - 1));
1398         if (ioctl(0, TIOCGWINSZ, (char *) &ws) >= 0) {
1399                 if (ws.ws_row > 2) rows = ws.ws_row - 2;
1400                 if (ws.ws_col > 8) cols = ws.ws_col - 8;
1401         }
1402         errno = save_errno;
1403 }
1404
1405
1406 /* is_legal_filename: return a legal filename */
1407 int
1408 is_legal_filename(char *s)
1409 {
1410         if (red && (*s == '!' || !strcmp(s, "..") || strchr(s, '/'))) {
1411                 errmsg = "shell access restricted";
1412                 return 0;
1413         }
1414         return 1;
1415 }