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