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 static sigjmp_buf env;
  70 #else
  71 static jmp_buf env;
  72 #endif
  73
  74 /* static buffers */
  75 char stdinbuf[1];               /* stdin buffer */
  76 static char *shcmd;             /* shell command buffer */
  77 static int shcmdsz;             /* shell command buffer size */
  78 static 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 static 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 static 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 static int sigactive = 0;       /* if set, signal handlers are enabled */
  94
  95 static 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 static const char *prompt;      /* command-line prompt */
 100 static const char *dps = "*";   /* default command-line prompt */
 101
 102 static 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;
 258 static long addr_cnt;
 259
 260 /* extract_addr_range: get line addresses from the command buffer until an
 261    illegal address is seen; return status */
 262 int
 263 extract_addr_range(void)
 264 {
 265         long addr;
 266
 267         addr_cnt = 0;
 268         first_addr = second_addr = current_addr;
 269         while ((addr = next_addr()) >= 0) {
 270                 addr_cnt++;
 271                 first_addr = second_addr;
 272                 second_addr = addr;
 273                 if (*ibufp != ',' && *ibufp != ';')
 274                         break;
 275                 else if (*ibufp++ == ';')
 276                         current_addr = addr;
 277         }
 278         if ((addr_cnt = min(addr_cnt, 2)) == 1 || second_addr != addr)
 279                 first_addr = second_addr;
 280         return (addr == ERR) ? ERR : 0;
 281 }
 282
 283
 284 #define SKIP_BLANKS() while (isspace((unsigned char)*ibufp) && *ibufp != '\n') ibufp++
 285
 286 #define MUST_BE_FIRST() do {                                    \
 287         if (!first) {                                           \
 288                 errmsg = "invalid address";                     \
 289                 return ERR;                                     \
 290         }                                                       \
 291 } while (0)
 292
 293 /*  next_addr: return the next line address in the command buffer */
 294 long
 295 next_addr(void)
 296 {
 297         const char *hd;
 298         long addr = current_addr;
 299         long n;
 300         int first = 1;
 301         int c;
 302
 303         SKIP_BLANKS();
 304         for (hd = ibufp;; first = 0)
 305                 switch (c = *ibufp) {
 306                 case '+':
 307                 case '\t':
 308                 case ' ':
 309                 case '-':
 310                 case '^':
 311                         ibufp++;
 312                         SKIP_BLANKS();
 313                         if (isdigit((unsigned char)*ibufp)) {
 314                                 STRTOL(n, ibufp);
 315                                 addr += (c == '-' || c == '^') ? -n : n;
 316                         } else if (!isspace((unsigned char)c))
 317                                 addr += (c == '-' || c == '^') ? -1 : 1;
 318                         break;
 319                 case '0': case '1': case '2':
 320                 case '3': case '4': case '5':
 321                 case '6': case '7': case '8': case '9':
 322                         MUST_BE_FIRST();
 323                         STRTOL(addr, ibufp);
 324                         break;
 325                 case '.':
 326                 case '$':
 327                         MUST_BE_FIRST();
 328                         ibufp++;
 329                         addr = (c == '.') ? current_addr : addr_last;
 330                         break;
 331                 case '/':
 332                 case '?':
 333                         MUST_BE_FIRST();
 334                         if ((addr = get_matching_node_addr(
 335                             get_compiled_pattern(), c == '/')) < 0)
 336                                 return ERR;
 337                         else if (c == *ibufp)
 338                                 ibufp++;
 339                         break;
 340                 case '\'':
 341                         MUST_BE_FIRST();
 342                         ibufp++;
 343                         if ((addr = get_marked_node_addr(*ibufp++)) < 0)
 344                                 return ERR;
 345                         break;
 346                 case '%':
 347                 case ',':
 348                 case ';':
 349                         if (first) {
 350                                 ibufp++;
 351                                 addr_cnt++;
 352                                 second_addr = (c == ';') ? current_addr : 1;
 353                                 addr = addr_last;
 354                                 break;
 355                         }
 356                         /* FALLTHROUGH */
 357                 default:
 358                         if (ibufp == hd)
 359                                 return EOF;
 360                         else if (addr < 0 || addr_last < addr) {
 361                                 errmsg = "invalid address";
 362                                 return ERR;
 363                         } else
 364                                 return addr;
 365                 }
 366         /* NOTREACHED */
 367 }
 368
 369
 370 #ifdef BACKWARDS
 371 /* GET_THIRD_ADDR: get a legal address from the command buffer */
 372 #define GET_THIRD_ADDR(addr) \
 373 { \
 374         long ol1, ol2; \
 375 \
 376         ol1 = first_addr, ol2 = second_addr; \
 377         if (extract_addr_range() < 0) \
 378                 return ERR; \
 379         else if (addr_cnt == 0) { \
 380                 errmsg = "destination expected"; \
 381                 return ERR; \
 382         } else if (second_addr < 0 || addr_last < second_addr) { \
 383                 errmsg = "invalid address"; \
 384                 return ERR; \
 385         } \
 386         addr = second_addr; \
 387         first_addr = ol1, second_addr = ol2; \
 388 }
 389 #else   /* BACKWARDS */
 390 /* GET_THIRD_ADDR: get a legal address from the command buffer */
 391 #define GET_THIRD_ADDR(addr) \
 392 { \
 393         long ol1, ol2; \
 394 \
 395         ol1 = first_addr, ol2 = second_addr; \
 396         if (extract_addr_range() < 0) \
 397                 return ERR; \
 398         if (second_addr < 0 || addr_last < second_addr) { \
 399                 errmsg = "invalid address"; \
 400                 return ERR; \
 401         } \
 402         addr = second_addr; \
 403         first_addr = ol1, second_addr = ol2; \
 404 }
 405 #endif
 406
 407
 408 /* GET_COMMAND_SUFFIX: verify the command suffix in the command buffer */
 409 #define GET_COMMAND_SUFFIX() { \
 410         int done = 0; \
 411         do { \
 412                 switch(*ibufp) { \
 413                 case 'p': \
 414                         gflag |= GPR, ibufp++; \
 415                         break; \
 416                 case 'l': \
 417                         gflag |= GLS, ibufp++; \
 418                         break; \
 419                 case 'n': \
 420                         gflag |= GNP, ibufp++; \
 421                         break; \
 422                 default: \
 423                         done++; \
 424                 } \
 425         } while (!done); \
 426         if (*ibufp++ != '\n') { \
 427                 errmsg = "invalid command suffix"; \
 428                 return ERR; \
 429         } \
 430 }
 431
 432
 433 /* sflags */
 434 #define SGG 001         /* complement previous global substitute suffix */
 435 #define SGP 002         /* complement previous print suffix */
 436 #define SGR 004         /* use last regex instead of last pat */
 437 #define SGF 010         /* repeat last substitution */
 438
 439 int patlock = 0;        /* if set, pattern not freed by get_compiled_pattern() */
 440
 441 long rows = 22;         /* scroll length: ws_row - 2 */
 442
 443 /* exec_command: execute the next command in command buffer; return print
 444    request, if any */
 445 int
 446 exec_command(void)
 447 {
 448         static pattern_t *pat = NULL;
 449         static int sgflag = 0;
 450         static long sgnum = 0;
 451
 452         pattern_t *tpat;
 453         char *fnp;
 454         int gflag = 0;
 455         int sflags = 0;
 456         long addr = 0;
 457         int n = 0;
 458         int c;
 459
 460         SKIP_BLANKS();
 461         switch(c = *ibufp++) {
 462         case 'a':
 463                 GET_COMMAND_SUFFIX();
 464                 if (!isglobal) clear_undo_stack();
 465                 if (append_lines(second_addr) < 0)
 466                         return ERR;
 467                 break;
 468         case 'c':
 469                 if (check_addr_range(current_addr, current_addr) < 0)
 470                         return ERR;
 471                 GET_COMMAND_SUFFIX();
 472                 if (!isglobal) clear_undo_stack();
 473                 if (delete_lines(first_addr, second_addr) < 0 ||
 474                     append_lines(current_addr) < 0)
 475                         return ERR;
 476                 break;
 477         case 'd':
 478                 if (check_addr_range(current_addr, current_addr) < 0)
 479                         return ERR;
 480                 GET_COMMAND_SUFFIX();
 481                 if (!isglobal) clear_undo_stack();
 482                 if (delete_lines(first_addr, second_addr) < 0)
 483                         return ERR;
 484                 else if ((addr = INC_MOD(current_addr, addr_last)) != 0)
 485                         current_addr = addr;
 486                 break;
 487         case 'e':
 488                 if (modified && !scripted)
 489                         return EMOD;
 490                 /* FALLTHROUGH */
 491         case 'E':
 492                 if (addr_cnt > 0) {
 493                         errmsg = "unexpected address";
 494                         return ERR;
 495                 } else if (!isspace((unsigned char)*ibufp)) {
 496                         errmsg = "unexpected command suffix";
 497                         return ERR;
 498                 } else if ((fnp = get_filename()) == NULL)
 499                         return ERR;
 500                 GET_COMMAND_SUFFIX();
 501                 if (delete_lines(1, addr_last) < 0)
 502                         return ERR;
 503                 clear_undo_stack();
 504                 if (close_sbuf() < 0)
 505                         return ERR;
 506                 else if (open_sbuf() < 0)
 507                         return FATAL;
 508                 if (*fnp && *fnp != '!')
 509                          strlcpy(old_filename, fnp, PATH_MAX);
 510 #ifdef BACKWARDS
 511                 if (*fnp == '\0' && *old_filename == '\0') {
 512                         errmsg = "no current filename";
 513                         return ERR;
 514                 }
 515 #endif
 516                 if (read_file(*fnp ? fnp : old_filename, 0) < 0)
 517                         return ERR;
 518                 clear_undo_stack();
 519                 modified = 0;
 520                 u_current_addr = u_addr_last = -1;
 521                 break;
 522         case 'f':
 523                 if (addr_cnt > 0) {
 524                         errmsg = "unexpected address";
 525                         return ERR;
 526                 } else if (!isspace((unsigned char)*ibufp)) {
 527                         errmsg = "unexpected command suffix";
 528                         return ERR;
 529                 } else if ((fnp = get_filename()) == NULL)
 530                         return ERR;
 531                 else if (*fnp == '!') {
 532                         errmsg = "invalid redirection";
 533                         return ERR;
 534                 }
 535                 GET_COMMAND_SUFFIX();
 536                 if (*fnp)
 537                         strlcpy(old_filename, fnp, PATH_MAX);
 538                 printf("%s\n", strip_escapes(old_filename));
 539                 break;
 540         case 'g':
 541         case 'v':
 542         case 'G':
 543         case 'V':
 544                 if (isglobal) {
 545                         errmsg = "cannot nest global commands";
 546                         return ERR;
 547                 } else if (check_addr_range(1, addr_last) < 0)
 548                         return ERR;
 549                 else if (build_active_list(c == 'g' || c == 'G') < 0)
 550                         return ERR;
 551                 else if ((n = (c == 'G' || c == 'V')))
 552                         GET_COMMAND_SUFFIX();
 553                 isglobal++;
 554                 if (exec_global(n, gflag) < 0)
 555                         return ERR;
 556                 break;
 557         case 'h':
 558                 if (addr_cnt > 0) {
 559                         errmsg = "unexpected address";
 560                         return ERR;
 561                 }
 562                 GET_COMMAND_SUFFIX();
 563                 if (*errmsg) fprintf(stderr, "%s\n", errmsg);
 564                 break;
 565         case 'H':
 566                 if (addr_cnt > 0) {
 567                         errmsg = "unexpected address";
 568                         return ERR;
 569                 }
 570                 GET_COMMAND_SUFFIX();
 571                 if ((garrulous = 1 - garrulous) && *errmsg)
 572                         fprintf(stderr, "%s\n", errmsg);
 573                 break;
 574         case 'i':
 575                 if (second_addr == 0) {
 576                         errmsg = "invalid address";
 577                         return ERR;
 578                 }
 579                 GET_COMMAND_SUFFIX();
 580                 if (!isglobal) clear_undo_stack();
 581                 if (append_lines(second_addr - 1) < 0)
 582                         return ERR;
 583                 break;
 584         case 'j':
 585                 if (check_addr_range(current_addr, current_addr + 1) < 0)
 586                         return ERR;
 587                 GET_COMMAND_SUFFIX();
 588                 if (!isglobal) clear_undo_stack();
 589                 if (first_addr != second_addr &&
 590                     join_lines(first_addr, second_addr) < 0)
 591                         return ERR;
 592                 break;
 593         case 'k':
 594                 c = *ibufp++;
 595                 if (second_addr == 0) {
 596                         errmsg = "invalid address";
 597                         return ERR;
 598                 }
 599                 GET_COMMAND_SUFFIX();
 600                 if (mark_line_node(get_addressed_line_node(second_addr), c) < 0)
 601                         return ERR;
 602                 break;
 603         case 'l':
 604                 if (check_addr_range(current_addr, current_addr) < 0)
 605                         return ERR;
 606                 GET_COMMAND_SUFFIX();
 607                 if (display_lines(first_addr, second_addr, gflag | GLS) < 0)
 608                         return ERR;
 609                 gflag = 0;
 610                 break;
 611         case 'm':
 612                 if (check_addr_range(current_addr, current_addr) < 0)
 613                         return ERR;
 614                 GET_THIRD_ADDR(addr);
 615                 if (first_addr <= addr && addr < second_addr) {
 616                         errmsg = "invalid destination";
 617                         return ERR;
 618                 }
 619                 GET_COMMAND_SUFFIX();
 620                 if (!isglobal) clear_undo_stack();
 621                 if (move_lines(addr) < 0)
 622                         return ERR;
 623                 break;
 624         case 'n':
 625                 if (check_addr_range(current_addr, current_addr) < 0)
 626                         return ERR;
 627                 GET_COMMAND_SUFFIX();
 628                 if (display_lines(first_addr, second_addr, gflag | GNP) < 0)
 629                         return ERR;
 630                 gflag = 0;
 631                 break;
 632         case 'p':
 633                 if (check_addr_range(current_addr, current_addr) < 0)
 634                         return ERR;
 635                 GET_COMMAND_SUFFIX();
 636                 if (display_lines(first_addr, second_addr, gflag | GPR) < 0)
 637                         return ERR;
 638                 gflag = 0;
 639                 break;
 640         case 'P':
 641                 if (addr_cnt > 0) {
 642                         errmsg = "unexpected address";
 643                         return ERR;
 644                 }
 645                 GET_COMMAND_SUFFIX();
 646                 prompt = prompt ? NULL : optarg ? optarg : dps;
 647                 break;
 648         case 'q':
 649         case 'Q':
 650                 if (addr_cnt > 0) {
 651                         errmsg = "unexpected address";
 652                         return ERR;
 653                 }
 654                 GET_COMMAND_SUFFIX();
 655                 gflag =  (modified && !scripted && c == 'q') ? EMOD : EOF;
 656                 break;
 657         case 'r':
 658                 if (!isspace((unsigned char)*ibufp)) {
 659                         errmsg = "unexpected command suffix";
 660                         return ERR;
 661                 } else if (addr_cnt == 0)
 662                         second_addr = addr_last;
 663                 if ((fnp = get_filename()) == NULL)
 664                         return ERR;
 665                 GET_COMMAND_SUFFIX();
 666                 if (!isglobal) clear_undo_stack();
 667                 if (*old_filename == '\0' && *fnp != '!')
 668                         strlcpy(old_filename, fnp, PATH_MAX);
 669 #ifdef BACKWARDS
 670                 if (*fnp == '\0' && *old_filename == '\0') {
 671                         errmsg = "no current filename";
 672                         return ERR;
 673                 }
 674 #endif
 675                 if ((addr = read_file(*fnp ? fnp : old_filename, second_addr)) < 0)
 676                         return ERR;
 677                 else if (addr && addr != addr_last)
 678                         modified = 1;
 679                 break;
 680         case 's':
 681                 do {
 682                         switch(*ibufp) {
 683                         case '\n':
 684                                 sflags |=SGF;
 685                                 break;
 686                         case 'g':
 687                                 sflags |= SGG;
 688                                 ibufp++;
 689                                 break;
 690                         case 'p':
 691                                 sflags |= SGP;
 692                                 ibufp++;
 693                                 break;
 694                         case 'r':
 695                                 sflags |= SGR;
 696                                 ibufp++;
 697                                 break;
 698                         case '0': case '1': case '2': case '3': case '4':
 699                         case '5': case '6': case '7': case '8': case '9':
 700                                 STRTOL(sgnum, ibufp);
 701                                 sflags |= SGF;
 702                                 sgflag &= ~GSG;         /* override GSG */
 703                                 break;
 704                         default:
 705                                 if (sflags) {
 706                                         errmsg = "invalid command suffix";
 707                                         return ERR;
 708                                 }
 709                         }
 710                 } while (sflags && *ibufp != '\n');
 711                 if (sflags && !pat) {
 712                         errmsg = "no previous substitution";
 713                         return ERR;
 714                 } else if (sflags & SGG)
 715                         sgnum = 0;              /* override numeric arg */
 716                 if (*ibufp != '\n' && *(ibufp + 1) == '\n') {
 717                         errmsg = "invalid pattern delimiter";
 718                         return ERR;
 719                 }
 720                 tpat = pat;
 721                 SPL1();
 722                 if ((!sflags || (sflags & SGR)) &&
 723                     (tpat = get_compiled_pattern()) == NULL) {
 724                         SPL0();
 725                         return ERR;
 726                 } else if (tpat != pat) {
 727                         if (pat) {
 728                                 regfree(pat);
 729                                 free(pat);
 730                         }
 731                         pat = tpat;
 732                         patlock = 1;            /* reserve pattern */
 733                 }
 734                 SPL0();
 735                 if (!sflags && extract_subst_tail(&sgflag, &sgnum) < 0)
 736                         return ERR;
 737                 else if (isglobal)
 738                         sgflag |= GLB;
 739                 else
 740                         sgflag &= ~GLB;
 741                 if (sflags & SGG)
 742                         sgflag ^= GSG;
 743                 if (sflags & SGP)
 744                         sgflag ^= GPR, sgflag &= ~(GLS | GNP);
 745                 do {
 746                         switch(*ibufp) {
 747                         case 'p':
 748                                 sgflag |= GPR, ibufp++;
 749                                 break;
 750                         case 'l':
 751                                 sgflag |= GLS, ibufp++;
 752                                 break;
 753                         case 'n':
 754                                 sgflag |= GNP, ibufp++;
 755                                 break;
 756                         default:
 757                                 n++;
 758                         }
 759                 } while (!n);
 760                 if (check_addr_range(current_addr, current_addr) < 0)
 761                         return ERR;
 762                 GET_COMMAND_SUFFIX();
 763                 if (!isglobal) clear_undo_stack();
 764                 if (search_and_replace(pat, sgflag, sgnum) < 0)
 765                         return ERR;
 766                 break;
 767         case 't':
 768                 if (check_addr_range(current_addr, current_addr) < 0)
 769                         return ERR;
 770                 GET_THIRD_ADDR(addr);
 771                 GET_COMMAND_SUFFIX();
 772                 if (!isglobal) clear_undo_stack();
 773                 if (copy_lines(addr) < 0)
 774                         return ERR;
 775                 break;
 776         case 'u':
 777                 if (addr_cnt > 0) {
 778                         errmsg = "unexpected address";
 779                         return ERR;
 780                 }
 781                 GET_COMMAND_SUFFIX();
 782                 if (pop_undo_stack() < 0)
 783                         return ERR;
 784                 break;
 785         case 'w':
 786         case 'W':
 787                 if ((n = *ibufp) == 'q' || n == 'Q') {
 788                         gflag = EOF;
 789                         ibufp++;
 790                 }
 791                 if (!isspace((unsigned char)*ibufp)) {
 792                         errmsg = "unexpected command suffix";
 793                         return ERR;
 794                 } else if ((fnp = get_filename()) == NULL)
 795                         return ERR;
 796                 if (addr_cnt == 0 && !addr_last)
 797                         first_addr = second_addr = 0;
 798                 else if (check_addr_range(1, addr_last) < 0)
 799                         return ERR;
 800                 GET_COMMAND_SUFFIX();
 801                 if (*old_filename == '\0' && *fnp != '!')
 802                         strlcpy(old_filename, fnp, PATH_MAX);
 803 #ifdef BACKWARDS
 804                 if (*fnp == '\0' && *old_filename == '\0') {
 805                         errmsg = "no current filename";
 806                         return ERR;
 807                 }
 808 #endif
 809                 if ((addr = write_file(*fnp ? fnp : old_filename,
 810                     (c == 'W') ? "a" : "w", first_addr, second_addr)) < 0)
 811                         return ERR;
 812                 else if (addr == addr_last)
 813                         modified = 0;
 814                 else if (modified && !scripted && n == 'q')
 815                         gflag = EMOD;
 816                 break;
 817         case 'x':
 818                 if (addr_cnt > 0) {
 819                         errmsg = "unexpected address";
 820                         return ERR;
 821                 }
 822                 GET_COMMAND_SUFFIX();
 823 #ifdef DES
 824                 des = get_keyword();
 825                 break;
 826 #else
 827                 errmsg = "crypt unavailable";
 828                 return ERR;
 829 #endif
 830         case 'z':
 831 #ifdef BACKWARDS
 832                 if (check_addr_range(first_addr = 1, current_addr + 1) < 0)
 833 #else
 834                 if (check_addr_range(first_addr = 1, current_addr + !isglobal) < 0)
 835 #endif
 836                         return ERR;
 837                 else if ('0' < *ibufp && *ibufp <= '9')
 838                         STRTOL(rows, ibufp);
 839                 GET_COMMAND_SUFFIX();
 840                 if (display_lines(second_addr, min(addr_last,
 841                     second_addr + rows), gflag) < 0)
 842                         return ERR;
 843                 gflag = 0;
 844                 break;
 845         case '=':
 846                 GET_COMMAND_SUFFIX();
 847                 printf("%ld\n", addr_cnt ? second_addr : addr_last);
 848                 break;
 849         case '!':
 850                 if (addr_cnt > 0) {
 851                         errmsg = "unexpected address";
 852                         return ERR;
 853                 } else if ((sflags = get_shell_command()) < 0)
 854                         return ERR;
 855                 GET_COMMAND_SUFFIX();
 856                 if (sflags) printf("%s\n", shcmd + 1);
 857                 system(shcmd + 1);
 858                 if (!scripted) printf("!\n");
 859                 break;
 860         case '\n':
 861 #ifdef BACKWARDS
 862                 if (check_addr_range(first_addr = 1, current_addr + 1) < 0
 863 #else
 864                 if (check_addr_range(first_addr = 1, current_addr + !isglobal) < 0
 865 #endif
 866                  || display_lines(second_addr, second_addr, 0) < 0)
 867                         return ERR;
 868                 break;
 869         default:
 870                 errmsg = "unknown command";
 871                 return ERR;
 872         }
 873         return gflag;
 874 }
 875
 876
 877 /* check_addr_range: return status of address range check */
 878 int
 879 check_addr_range(long n, long m)
 880 {
 881         if (addr_cnt == 0) {
 882                 first_addr = n;
 883                 second_addr = m;
 884         }
 885         if (first_addr > second_addr || 1 > first_addr ||
 886             second_addr > addr_last) {
 887                 errmsg = "invalid address";
 888                 return ERR;
 889         }
 890         return 0;
 891 }
 892
 893
 894 /* get_matching_node_addr: return the address of the next line matching a
 895    pattern in a given direction.  wrap around begin/end of editor buffer if
 896    necessary */
 897 long
 898 get_matching_node_addr(pattern_t *pat, int dir)
 899 {
 900         char *s;
 901         long n = current_addr;
 902         line_t *lp;
 903
 904         if (!pat) return ERR;
 905         do {
 906                if ((n = dir ? INC_MOD(n, addr_last) : DEC_MOD(n, addr_last))) {
 907                         lp = get_addressed_line_node(n);
 908                         if ((s = get_sbuf_line(lp)) == NULL)
 909                                 return ERR;
 910                         if (isbinary)
 911                                 NUL_TO_NEWLINE(s, lp->len);
 912                         if (!regexec(pat, s, 0, NULL, 0))
 913                                 return n;
 914                }
 915         } while (n != current_addr);
 916         errmsg = "no match";
 917         return  ERR;
 918 }
 919
 920
 921 /* get_filename: return pointer to copy of filename in the command buffer */
 922 char *
 923 get_filename(void)
 924 {
 925         static char *file = NULL;
 926         static int filesz = 0;
 927
 928         int n;
 929
 930         if (*ibufp != '\n') {
 931                 SKIP_BLANKS();
 932                 if (*ibufp == '\n') {
 933                         errmsg = "invalid filename";
 934                         return NULL;
 935                 } else if ((ibufp = get_extended_line(&n, 1)) == NULL)
 936                         return NULL;
 937                 else if (*ibufp == '!') {
 938                         ibufp++;
 939                         if ((n = get_shell_command()) < 0)
 940                                 return NULL;
 941                         if (n)
 942                                 printf("%s\n", shcmd + 1);
 943                         return shcmd;
 944                 } else if (n > PATH_MAX - 1) {
 945                         errmsg = "filename too long";
 946                         return  NULL;
 947                 }
 948         }
 949 #ifndef BACKWARDS
 950         else if (*old_filename == '\0') {
 951                 errmsg = "no current filename";
 952                 return  NULL;
 953         }
 954 #endif
 955         REALLOC(file, filesz, PATH_MAX, NULL);
 956         for (n = 0; *ibufp != '\n';)
 957                 file[n++] = *ibufp++;
 958         file[n] = '\0';
 959         return is_legal_filename(file) ? file : NULL;
 960 }
 961
 962
 963 /* get_shell_command: read a shell command from stdin; return substitution
 964    status */
 965 int
 966 get_shell_command(void)
 967 {
 968         static char *buf = NULL;
 969         static int n = 0;
 970
 971         char *s;                        /* substitution char pointer */
 972         int i = 0;
 973         int j = 0;
 974
 975         if (red) {
 976                 errmsg = "shell access restricted";
 977                 return ERR;
 978         } else if ((s = ibufp = get_extended_line(&j, 1)) == NULL)
 979                 return ERR;
 980         REALLOC(buf, n, j + 1, ERR);
 981         buf[i++] = '!';                 /* prefix command w/ bang */
 982         while (*ibufp != '\n')
 983                 switch (*ibufp) {
 984                 default:
 985                         REALLOC(buf, n, i + 2, ERR);
 986                         buf[i++] = *ibufp;
 987                         if (*ibufp++ == '\\')
 988                                 buf[i++] = *ibufp++;
 989                         break;
 990                 case '!':
 991                         if (s != ibufp) {
 992                                 REALLOC(buf, n, i + 1, ERR);
 993                                 buf[i++] = *ibufp++;
 994                         }
 995 #ifdef BACKWARDS
 996                         else if (shcmd == NULL || *(shcmd + 1) == '\0')
 997 #else
 998                         else if (shcmd == NULL)
 999 #endif
1000                         {
1001                                 errmsg = "no previous command";
1002                                 return ERR;
1003                         } else {
1004                                 REALLOC(buf, n, i + shcmdi, ERR);
1005                                 for (s = shcmd + 1; s < shcmd + shcmdi;)
1006                                         buf[i++] = *s++;
1007                                 s = ibufp++;
1008                         }
1009                         break;
1010                 case '%':
1011                         if (*old_filename  == '\0') {
1012                                 errmsg = "no current filename";
1013                                 return ERR;
1014                         }
1015                         j = strlen(s = strip_escapes(old_filename));
1016                         REALLOC(buf, n, i + j, ERR);
1017                         while (j--)
1018                                 buf[i++] = *s++;
1019                         s = ibufp++;
1020                         break;
1021                 }
1022         REALLOC(shcmd, shcmdsz, i + 1, ERR);
1023         memcpy(shcmd, buf, i);
1024         shcmd[shcmdi = i] = '\0';
1025         return *s == '!' || *s == '%';
1026 }
1027
1028
1029 /* append_lines: insert text from stdin to after line n; stop when either a
1030    single period is read or EOF; return status */
1031 int
1032 append_lines(long n)
1033 {
1034         int l;
1035         const char *lp = ibuf;
1036         const char *eot;
1037         undo_t *up = NULL;
1038
1039         for (current_addr = n;;) {
1040                 if (!isglobal) {
1041                         if ((l = get_tty_line()) < 0)
1042                                 return ERR;
1043                         else if (l == 0 || ibuf[l - 1] != '\n') {
1044                                 clearerr(stdin);
1045                                 return  l ? EOF : 0;
1046                         }
1047                         lp = ibuf;
1048                 } else if (*(lp = ibufp) == '\0')
1049                         return 0;
1050                 else {
1051                         while (*ibufp++ != '\n')
1052                                 ;
1053                         l = ibufp - lp;
1054                 }
1055                 if (l == 2 && lp[0] == '.' && lp[1] == '\n') {
1056                         return 0;
1057                 }
1058                 eot = lp + l;
1059                 SPL1();
1060                 do {
1061                         if ((lp = put_sbuf_line(lp)) == NULL) {
1062                                 SPL0();
1063                                 return ERR;
1064                         } else if (up)
1065                                 up->t = get_addressed_line_node(current_addr);
1066                         else if ((up = push_undo_stack(UADD, current_addr,
1067                             current_addr)) == NULL) {
1068                                 SPL0();
1069                                 return ERR;
1070                         }
1071                 } while (lp != eot);
1072                 modified = 1;
1073                 SPL0();
1074         }
1075         /* NOTREACHED */
1076 }
1077
1078
1079 /* join_lines: replace a range of lines with the joined text of those lines */
1080 int
1081 join_lines(long from, long to)
1082 {
1083         static char *buf = NULL;
1084         static int n;
1085
1086         char *s;
1087         int size = 0;
1088         line_t *bp, *ep;
1089
1090         ep = get_addressed_line_node(INC_MOD(to, addr_last));
1091         bp = get_addressed_line_node(from);
1092         for (; bp != ep; bp = bp->q_forw) {
1093                 if ((s = get_sbuf_line(bp)) == NULL)
1094                         return ERR;
1095                 REALLOC(buf, n, size + bp->len, ERR);
1096                 memcpy(buf + size, s, bp->len);
1097                 size += bp->len;
1098         }
1099         REALLOC(buf, n, size + 2, ERR);
1100         memcpy(buf + size, "\n", 2);
1101         if (delete_lines(from, to) < 0)
1102                 return ERR;
1103         current_addr = from - 1;
1104         SPL1();
1105         if (put_sbuf_line(buf) == NULL ||
1106             push_undo_stack(UADD, current_addr, current_addr) == NULL) {
1107                 SPL0();
1108                 return ERR;
1109         }
1110         modified = 1;
1111         SPL0();
1112         return 0;
1113 }
1114
1115
1116 /* move_lines: move a range of lines */
1117 int
1118 move_lines(long addr)
1119 {
1120         line_t *b1, *a1, *b2, *a2;
1121         long n = INC_MOD(second_addr, addr_last);
1122         long p = first_addr - 1;
1123         int done = (addr == first_addr - 1 || addr == second_addr);
1124
1125         SPL1();
1126         if (done) {
1127                 a2 = get_addressed_line_node(n);
1128                 b2 = get_addressed_line_node(p);
1129                 current_addr = second_addr;
1130         } else if (push_undo_stack(UMOV, p, n) == NULL ||
1131             push_undo_stack(UMOV, addr, INC_MOD(addr, addr_last)) == NULL) {
1132                 SPL0();
1133                 return ERR;
1134         } else {
1135                 a1 = get_addressed_line_node(n);
1136                 if (addr < first_addr) {
1137                         b1 = get_addressed_line_node(p);
1138                         b2 = get_addressed_line_node(addr);
1139                                         /* this get_addressed_line_node last! */
1140                 } else {
1141                         b2 = get_addressed_line_node(addr);
1142                         b1 = get_addressed_line_node(p);
1143                                         /* this get_addressed_line_node last! */
1144                 }
1145                 a2 = b2->q_forw;
1146                 REQUE(b2, b1->q_forw);
1147                 REQUE(a1->q_back, a2);
1148                 REQUE(b1, a1);
1149                 current_addr = addr + ((addr < first_addr) ?
1150                     second_addr - first_addr + 1 : 0);
1151         }
1152         if (isglobal)
1153                 unset_active_nodes(b2->q_forw, a2);
1154         modified = 1;
1155         SPL0();
1156         return 0;
1157 }
1158
1159
1160 /* copy_lines: copy a range of lines; return status */
1161 int
1162 copy_lines(long addr)
1163 {
1164         line_t *lp, *np = get_addressed_line_node(first_addr);
1165         undo_t *up = NULL;
1166         long n = second_addr - first_addr + 1;
1167         long m = 0;
1168
1169         current_addr = addr;
1170         if (first_addr <= addr && addr < second_addr) {
1171                 n =  addr - first_addr + 1;
1172                 m = second_addr - addr;
1173         }
1174         for (; n > 0; n=m, m=0, np = get_addressed_line_node(current_addr + 1))
1175                 for (; n-- > 0; np = np->q_forw) {
1176                         SPL1();
1177                         if ((lp = dup_line_node(np)) == NULL) {
1178                                 SPL0();
1179                                 return ERR;
1180                         }
1181                         add_line_node(lp);
1182                         if (up)
1183                                 up->t = lp;
1184                         else if ((up = push_undo_stack(UADD, current_addr,
1185                             current_addr)) == NULL) {
1186                                 SPL0();
1187                                 return ERR;
1188                         }
1189                         modified = 1;
1190                         SPL0();
1191                 }
1192         return 0;
1193 }
1194
1195
1196 /* delete_lines: delete a range of lines */
1197 int
1198 delete_lines(long from, long to)
1199 {
1200         line_t *n, *p;
1201
1202         SPL1();
1203         if (push_undo_stack(UDEL, from, to) == NULL) {
1204                 SPL0();
1205                 return ERR;
1206         }
1207         n = get_addressed_line_node(INC_MOD(to, addr_last));
1208         p = get_addressed_line_node(from - 1);
1209                                         /* this get_addressed_line_node last! */
1210         if (isglobal)
1211                 unset_active_nodes(p->q_forw, n);
1212         REQUE(p, n);
1213         addr_last -= to - from + 1;
1214         current_addr = from - 1;
1215         modified = 1;
1216         SPL0();
1217         return 0;
1218 }
1219
1220
1221 /* display_lines: print a range of lines to stdout */
1222 int
1223 display_lines(long from, long to, int gflag)
1224 {
1225         line_t *bp;
1226         line_t *ep;
1227         char *s;
1228
1229         if (!from) {
1230                 errmsg = "invalid address";
1231                 return ERR;
1232         }
1233         ep = get_addressed_line_node(INC_MOD(to, addr_last));
1234         bp = get_addressed_line_node(from);
1235         for (; bp != ep; bp = bp->q_forw) {
1236                 if ((s = get_sbuf_line(bp)) == NULL)
1237                         return ERR;
1238                 if (put_tty_line(s, bp->len, current_addr = from++, gflag) < 0)
1239                         return ERR;
1240         }
1241         return 0;
1242 }
1243
1244
1245 #define MAXMARK 26                      /* max number of marks */
1246
1247 static line_t *mark[MAXMARK];           /* line markers */
1248 static int markno;                      /* line marker count */
1249
1250 /* mark_line_node: set a line node mark */
1251 int
1252 mark_line_node(line_t *lp, int n)
1253 {
1254         if (!islower((unsigned char)n)) {
1255                 errmsg = "invalid mark character";
1256                 return ERR;
1257         } else if (mark[n - 'a'] == NULL)
1258                 markno++;
1259         mark[n - 'a'] = lp;
1260         return 0;
1261 }
1262
1263
1264 /* get_marked_node_addr: return address of a marked line */
1265 long
1266 get_marked_node_addr(int n)
1267 {
1268         if (!islower((unsigned char)n)) {
1269                 errmsg = "invalid mark character";
1270                 return ERR;
1271         }
1272         return get_line_node_addr(mark[n - 'a']);
1273 }
1274
1275
1276 /* unmark_line_node: clear line node mark */
1277 void
1278 unmark_line_node(line_t *lp)
1279 {
1280         int i;
1281
1282         for (i = 0; markno && i < MAXMARK; i++)
1283                 if (mark[i] == lp) {
1284                         mark[i] = NULL;
1285                         markno--;
1286                 }
1287 }
1288
1289
1290 /* dup_line_node: return a pointer to a copy of a line node */
1291 line_t *
1292 dup_line_node(line_t *lp)
1293 {
1294         line_t *np;
1295
1296         if ((np = (line_t *) malloc(sizeof(line_t))) == NULL) {
1297                 fprintf(stderr, "%s\n", strerror(errno));
1298                 errmsg = "out of memory";
1299                 return NULL;
1300         }
1301         np->seek = lp->seek;
1302         np->len = lp->len;
1303         return np;
1304 }
1305
1306
1307 /* has_trailing_escape:  return the parity of escapes preceding a character
1308    in a string */
1309 int
1310 has_trailing_escape(char *s, char *t)
1311 {
1312     return (s == t || *(t - 1) != '\\') ? 0 : !has_trailing_escape(s, t - 1);
1313 }
1314
1315
1316 /* strip_escapes: return copy of escaped string of at most length PATH_MAX */
1317 char *
1318 strip_escapes(char *s)
1319 {
1320         static char *file = NULL;
1321         static int filesz = 0;
1322
1323         int i = 0;
1324
1325         REALLOC(file, filesz, PATH_MAX, NULL);
1326         while (i < filesz - 1   /* Worry about a possible trailing escape */
1327                && (file[i++] = (*s == '\\') ? *++s : *s))
1328                 s++;
1329         return file;
1330 }
1331
1332
1333 void
1334 signal_hup(int signo)
1335 {
1336         if (mutex)
1337                 sigflags |= (1 << (signo - 1));
1338         else
1339                 handle_hup(signo);
1340 }
1341
1342
1343 void
1344 signal_int(int signo)
1345 {
1346         if (mutex)
1347                 sigflags |= (1 << (signo - 1));
1348         else
1349                 handle_int(signo);
1350 }
1351
1352
1353 void
1354 handle_hup(int signo)
1355 {
1356         char *hup = NULL;               /* hup filename */
1357         char *s;
1358         char ed_hup[] = "ed.hup";
1359         int n;
1360
1361         if (!sigactive)
1362                 quit(1);
1363         sigflags &= ~(1 << (signo - 1));
1364         if (addr_last && write_file(ed_hup, "w", 1, addr_last) < 0 &&
1365             (s = getenv("HOME")) != NULL &&
1366             (n = strlen(s)) + 8 <= PATH_MAX &&  /* "ed.hup" + '/' */
1367             (hup = (char *) malloc(n + 10)) != NULL) {
1368                 strcpy(hup, s);
1369                 if (hup[n - 1] != '/')
1370                         hup[n] = '/', hup[n+1] = '\0';
1371                 strcat(hup, "ed.hup");
1372                 write_file(hup, "w", 1, addr_last);
1373         }
1374         quit(2);
1375 }
1376
1377
1378 void
1379 handle_int(int signo)
1380 {
1381         if (!sigactive)
1382                 quit(1);
1383         sigflags &= ~(1 << (signo - 1));
1384 #ifdef _POSIX_SOURCE
1385         siglongjmp(env, -1);
1386 #else
1387         longjmp(env, -1);
1388 #endif
1389 }
1390
1391
1392 int cols = 72;                          /* wrap column */
1393
1394 void
1395 handle_winch(int signo)
1396 {
1397         int save_errno = errno;
1398
1399         struct winsize ws;              /* window size structure */
1400
1401         sigflags &= ~(1 << (signo - 1));
1402         if (ioctl(0, TIOCGWINSZ, (char *) &ws) >= 0) {
1403                 if (ws.ws_row > 2) rows = ws.ws_row - 2;
1404                 if (ws.ws_col > 8) cols = ws.ws_col - 8;
1405         }
1406         errno = save_errno;
1407 }
1408
1409
1410 /* is_legal_filename: return a legal filename */
1411 int
1412 is_legal_filename(char *s)
1413 {
1414         if (red && (*s == '!' || !strcmp(s, "..") || strchr(s, '/'))) {
1415                 errmsg = "shell access restricted";
1416                 return 0;
1417         }
1418         return 1;
1419 }