contrib/less/filename.c

   1 /*
   2  * Copyright (C) 1984-2011  Mark Nudelman
   3  *
   4  * You may distribute under the terms of either the GNU General Public
   5  * License or the Less License, as specified in the README file.
   6  *
   7  * For more information about less, or for information on how to
   8  * contact the author, see the README file.
   9  */
  10
  11
  12 /*
  13  * Routines to mess around with filenames (and files).
  14  * Much of this is very OS dependent.
  15  */
  16
  17 #include "less.h"
  18 #include "lglob.h"
  19 #if MSDOS_COMPILER
  20 #include <dos.h>
  21 #if MSDOS_COMPILER==WIN32C && !defined(_MSC_VER)
  22 #include <dir.h>
  23 #endif
  24 #if MSDOS_COMPILER==DJGPPC
  25 #include <glob.h>
  26 #include <dir.h>
  27 #define _MAX_PATH       PATH_MAX
  28 #endif
  29 #endif
  30 #ifdef _OSK
  31 #include <rbf.h>
  32 #ifndef _OSK_MWC32
  33 #include <modes.h>
  34 #endif
  35 #endif
  36 #if OS2
  37 #include <signal.h>
  38 #endif
  39
  40 #if HAVE_STAT
  41 #include <sys/stat.h>
  42 #ifndef S_ISDIR
  43 #define S_ISDIR(m)      (((m) & S_IFMT) == S_IFDIR)
  44 #endif
  45 #ifndef S_ISREG
  46 #define S_ISREG(m)      (((m) & S_IFMT) == S_IFREG)
  47 #endif
  48 #endif
  49
  50
  51 extern int force_open;
  52 extern int secure;
  53 extern int use_lessopen;
  54 extern int ctldisp;
  55 extern int utf_mode;
  56 extern IFILE curr_ifile;
  57 extern IFILE old_ifile;
  58 #if SPACES_IN_FILENAMES
  59 extern char openquote;
  60 extern char closequote;
  61 #endif
  62
  63 /*
  64  * Remove quotes around a filename.
  65  */
  66         public char *
  67 shell_unquote(str)
  68         char *str;
  69 {
  70         char *name;
  71         char *p;
  72
  73         name = p = (char *) ecalloc(strlen(str)+1, sizeof(char));
  74         if (*str == openquote)
  75         {
  76                 str++;
  77                 while (*str != '\0')
  78                 {
  79                         if (*str == closequote)
  80                         {
  81                                 if (str[1] != closequote)
  82                                         break;
  83                                 str++;
  84                         }
  85                         *p++ = *str++;
  86                 }
  87         } else
  88         {
  89                 char *esc = get_meta_escape();
  90                 int esclen = strlen(esc);
  91                 while (*str != '\0')
  92                 {
  93                         if (esclen > 0 && strncmp(str, esc, esclen) == 0)
  94                                 str += esclen;
  95                         *p++ = *str++;
  96                 }
  97         }
  98         *p = '\0';
  99         return (name);
 100 }
 101
 102 /*
 103  * Get the shell's escape character.
 104  */
 105         public char *
 106 get_meta_escape()
 107 {
 108         char *s;
 109
 110         s = lgetenv("LESSMETAESCAPE");
 111         if (s == NULL)
 112                 s = DEF_METAESCAPE;
 113         return (s);
 114 }
 115
 116 /*
 117  * Get the characters which the shell considers to be "metacharacters".
 118  */
 119         static char *
 120 metachars()
 121 {
 122         static char *mchars = NULL;
 123
 124         if (mchars == NULL)
 125         {
 126                 mchars = lgetenv("LESSMETACHARS");
 127                 if (mchars == NULL)
 128                         mchars = DEF_METACHARS;
 129         }
 130         return (mchars);
 131 }
 132
 133 /*
 134  * Is this a shell metacharacter?
 135  */
 136         static int
 137 metachar(c)
 138         char c;
 139 {
 140         return (strchr(metachars(), c) != NULL);
 141 }
 142
 143 /*
 144  * Insert a backslash before each metacharacter in a string.
 145  */
 146         public char *
 147 shell_quote(s)
 148         char *s;
 149 {
 150         char *p;
 151         char *newstr;
 152         int len;
 153         char *esc = get_meta_escape();
 154         int esclen = strlen(esc);
 155         int use_quotes = 0;
 156         int have_quotes = 0;
 157
 158         /*
 159          * Determine how big a string we need to allocate.
 160          */
 161         len = 1; /* Trailing null byte */
 162         for (p = s;  *p != '\0';  p++)
 163         {
 164                 len++;
 165                 if (*p == openquote || *p == closequote)
 166                         have_quotes = 1;
 167                 if (metachar(*p))
 168                 {
 169                         if (esclen == 0)
 170                         {
 171                                 /*
 172                                  * We've got a metachar, but this shell
 173                                  * doesn't support escape chars.  Use quotes.
 174                                  */
 175                                 use_quotes = 1;
 176                         } else
 177                         {
 178                                 /*
 179                                  * Allow space for the escape char.
 180                                  */
 181                                 len += esclen;
 182                         }
 183                 }
 184         }
 185         if (use_quotes)
 186         {
 187                 if (have_quotes)
 188                         /*
 189                          * We can't quote a string that contains quotes.
 190                          */
 191                         return (NULL);
 192                 len = strlen(s) + 3;
 193         }
 194         /*
 195          * Allocate and construct the new string.
 196          */
 197         newstr = p = (char *) ecalloc(len, sizeof(char));
 198         if (use_quotes)
 199         {
 200                 SNPRINTF3(newstr, len, "%c%s%c", openquote, s, closequote);
 201         } else
 202         {
 203                 while (*s != '\0')
 204                 {
 205                         if (metachar(*s))
 206                         {
 207                                 /*
 208                                  * Add the escape char.
 209                                  */
 210                                 strcpy(p, esc);
 211                                 p += esclen;
 212                         }
 213                         *p++ = *s++;
 214                 }
 215                 *p = '\0';
 216         }
 217         return (newstr);
 218 }
 219
 220 /*
 221  * Return a pathname that points to a specified file in a specified directory.
 222  * Return NULL if the file does not exist in the directory.
 223  */
 224         static char *
 225 dirfile(dirname, filename)
 226         char *dirname;
 227         char *filename;
 228 {
 229         char *pathname;
 230         char *qpathname;
 231         int len;
 232         int f;
 233
 234         if (dirname == NULL || *dirname == '\0')
 235                 return (NULL);
 236         /*
 237          * Construct the full pathname.
 238          */
 239         len= strlen(dirname) + strlen(filename) + 2;
 240         pathname = (char *) calloc(len, sizeof(char));
 241         if (pathname == NULL)
 242                 return (NULL);
 243         SNPRINTF3(pathname, len, "%s%s%s", dirname, PATHNAME_SEP, filename);
 244         /*
 245          * Make sure the file exists.
 246          */
 247         qpathname = shell_unquote(pathname);
 248         f = open(qpathname, OPEN_READ);
 249         if (f < 0)
 250         {
 251                 free(pathname);
 252                 pathname = NULL;
 253         } else
 254         {
 255                 close(f);
 256         }
 257         free(qpathname);
 258         return (pathname);
 259 }
 260
 261 /*
 262  * Return the full pathname of the given file in the "home directory".
 263  */
 264         public char *
 265 homefile(filename)
 266         char *filename;
 267 {
 268         register char *pathname;
 269
 270         /*
 271          * Try $HOME/filename.
 272          */
 273         pathname = dirfile(lgetenv("HOME"), filename);
 274         if (pathname != NULL)
 275                 return (pathname);
 276 #if OS2
 277         /*
 278          * Try $INIT/filename.
 279          */
 280         pathname = dirfile(lgetenv("INIT"), filename);
 281         if (pathname != NULL)
 282                 return (pathname);
 283 #endif
 284 #if MSDOS_COMPILER || OS2
 285         /*
 286          * Look for the file anywhere on search path.
 287          */
 288         pathname = (char *) calloc(_MAX_PATH, sizeof(char));
 289 #if MSDOS_COMPILER==DJGPPC
 290         {
 291                 char *res = searchpath(filename);
 292                 if (res == 0)
 293                         *pathname = '\0';
 294                 else
 295                         strcpy(pathname, res);
 296         }
 297 #else
 298         _searchenv(filename, "PATH", pathname);
 299 #endif
 300         if (*pathname != '\0')
 301                 return (pathname);
 302         free(pathname);
 303 #endif
 304         return (NULL);
 305 }
 306
 307 /*
 308  * Expand a string, substituting any "%" with the current filename,
 309  * and any "#" with the previous filename.
 310  * But a string of N "%"s is just replaced with N-1 "%"s.
 311  * Likewise for a string of N "#"s.
 312  * {{ This is a lot of work just to support % and #. }}
 313  */
 314         public char *
 315 fexpand(s)
 316         char *s;
 317 {
 318         register char *fr, *to;
 319         register int n;
 320         register char *e;
 321         IFILE ifile;
 322
 323 #define fchar_ifile(c) \
 324         ((c) == '%' ? curr_ifile : \
 325          (c) == '#' ? old_ifile : NULL_IFILE)
 326
 327         /*
 328          * Make one pass to see how big a buffer we
 329          * need to allocate for the expanded string.
 330          */
 331         n = 0;
 332         for (fr = s;  *fr != '\0';  fr++)
 333         {
 334                 switch (*fr)
 335                 {
 336                 case '%':
 337                 case '#':
 338                         if (fr > s && fr[-1] == *fr)
 339                         {
 340                                 /*
 341                                  * Second (or later) char in a string
 342                                  * of identical chars.  Treat as normal.
 343                                  */
 344                                 n++;
 345                         } else if (fr[1] != *fr)
 346                         {
 347                                 /*
 348                                  * Single char (not repeated).  Treat specially.
 349                                  */
 350                                 ifile = fchar_ifile(*fr);
 351                                 if (ifile == NULL_IFILE)
 352                                         n++;
 353                                 else
 354                                         n += strlen(get_filename(ifile));
 355                         }
 356                         /*
 357                          * Else it is the first char in a string of
 358                          * identical chars.  Just discard it.
 359                          */
 360                         break;
 361                 default:
 362                         n++;
 363                         break;
 364                 }
 365         }
 366
 367         e = (char *) ecalloc(n+1, sizeof(char));
 368
 369         /*
 370          * Now copy the string, expanding any "%" or "#".
 371          */
 372         to = e;
 373         for (fr = s;  *fr != '\0';  fr++)
 374         {
 375                 switch (*fr)
 376                 {
 377                 case '%':
 378                 case '#':
 379                         if (fr > s && fr[-1] == *fr)
 380                         {
 381                                 *to++ = *fr;
 382                         } else if (fr[1] != *fr)
 383                         {
 384                                 ifile = fchar_ifile(*fr);
 385                                 if (ifile == NULL_IFILE)
 386                                         *to++ = *fr;
 387                                 else
 388                                 {
 389                                         strcpy(to, get_filename(ifile));
 390                                         to += strlen(to);
 391                                 }
 392                         }
 393                         break;
 394                 default:
 395                         *to++ = *fr;
 396                         break;
 397                 }
 398         }
 399         *to = '\0';
 400         return (e);
 401 }
 402
 403
 404 #if TAB_COMPLETE_FILENAME
 405
 406 /*
 407  * Return a blank-separated list of filenames which "complete"
 408  * the given string.
 409  */
 410         public char *
 411 fcomplete(s)
 412         char *s;
 413 {
 414         char *fpat;
 415         char *qs;
 416
 417         if (secure)
 418                 return (NULL);
 419         /*
 420          * Complete the filename "s" by globbing "s*".
 421          */
 422 #if MSDOS_COMPILER && (MSDOS_COMPILER == MSOFTC || MSDOS_COMPILER == BORLANDC)
 423         /*
 424          * But in DOS, we have to glob "s*.*".
 425          * But if the final component of the filename already has
 426          * a dot in it, just do "s*".
 427          * (Thus, "FILE" is globbed as "FILE*.*",
 428          *  but "FILE.A" is globbed as "FILE.A*").
 429          */
 430         {
 431                 char *slash;
 432                 int len;
 433                 for (slash = s+strlen(s)-1;  slash > s;  slash--)
 434                         if (*slash == *PATHNAME_SEP || *slash == '/')
 435                                 break;
 436                 len = strlen(s) + 4;
 437                 fpat = (char *) ecalloc(len, sizeof(char));
 438                 if (strchr(slash, '.') == NULL)
 439                         SNPRINTF1(fpat, len, "%s*.*", s);
 440                 else
 441                         SNPRINTF1(fpat, len, "%s*", s);
 442         }
 443 #else
 444         {
 445         int len = strlen(s) + 2;
 446         fpat = (char *) ecalloc(len, sizeof(char));
 447         SNPRINTF1(fpat, len, "%s*", s);
 448         }
 449 #endif
 450         qs = lglob(fpat);
 451         s = shell_unquote(qs);
 452         if (strcmp(s,fpat) == 0)
 453         {
 454                 /*
 455                  * The filename didn't expand.
 456                  */
 457                 free(qs);
 458                 qs = NULL;
 459         }
 460         free(s);
 461         free(fpat);
 462         return (qs);
 463 }
 464 #endif
 465
 466 /*
 467  * Try to determine if a file is "binary".
 468  * This is just a guess, and we need not try too hard to make it accurate.
 469  */
 470         public int
 471 bin_file(f)
 472         int f;
 473 {
 474         int n;
 475         int bin_count = 0;
 476         char data[256];
 477         char* p;
 478         char* pend;
 479
 480         if (!seekable(f))
 481                 return (0);
 482         if (lseek(f, (off_t)0, SEEK_SET) == BAD_LSEEK)
 483                 return (0);
 484         n = read(f, data, sizeof(data));
 485         pend = &data[n];
 486         for (p = data;  p < pend;  )
 487         {
 488                 LWCHAR c = step_char(&p, +1, pend);
 489                 if (ctldisp == OPT_ONPLUS && IS_CSI_START(c))
 490                 {
 491                         do {
 492                                 c = step_char(&p, +1, pend);
 493                         } while (p < pend && is_ansi_middle(c));
 494                 } else if (binary_char(c))
 495                         bin_count++;
 496         }
 497         /*
 498          * Call it a binary file if there are more than 5 binary characters
 499          * in the first 256 bytes of the file.
 500          */
 501         return (bin_count > 5);
 502 }
 503
 504 /*
 505  * Try to determine the size of a file by seeking to the end.
 506  */
 507         static POSITION
 508 seek_filesize(f)
 509         int f;
 510 {
 511         off_t spos;
 512
 513         spos = lseek(f, (off_t)0, SEEK_END);
 514         if (spos == BAD_LSEEK)
 515                 return (NULL_POSITION);
 516         return ((POSITION) spos);
 517 }
 518
 519 /*
 520  * Read a string from a file.
 521  * Return a pointer to the string in memory.
 522  */
 523         static char *
 524 readfd(fd)
 525         FILE *fd;
 526 {
 527         int len;
 528         int ch;
 529         char *buf;
 530         char *p;
 531
 532         /*
 533          * Make a guess about how many chars in the string
 534          * and allocate a buffer to hold it.
 535          */
 536         len = 100;
 537         buf = (char *) ecalloc(len, sizeof(char));
 538         for (p = buf;  ;  p++)
 539         {
 540                 if ((ch = getc(fd)) == '\n' || ch == EOF)
 541                         break;
 542                 if (p - buf >= len-1)
 543                 {
 544                         /*
 545                          * The string is too big to fit in the buffer we have.
 546                          * Allocate a new buffer, twice as big.
 547                          */
 548                         len *= 2;
 549                         *p = '\0';
 550                         p = (char *) ecalloc(len, sizeof(char));
 551                         strcpy(p, buf);
 552                         free(buf);
 553                         buf = p;
 554                         p = buf + strlen(buf);
 555                 }
 556                 *p = ch;
 557         }
 558         *p = '\0';
 559         return (buf);
 560 }
 561
 562
 563
 564 #if HAVE_POPEN
 565
 566 FILE *popen();
 567
 568 /*
 569  * Execute a shell command.
 570  * Return a pointer to a pipe connected to the shell command's standard output.
 571  */
 572         static FILE *
 573 shellcmd(cmd)
 574         char *cmd;
 575 {
 576         FILE *fd;
 577
 578 #if HAVE_SHELL
 579         char *shell;
 580
 581         shell = lgetenv("SHELL");
 582         if (shell != NULL && *shell != '\0')
 583         {
 584                 char *scmd;
 585                 char *esccmd;
 586
 587                 /*
 588                  * Read the output of <$SHELL -c cmd>.
 589                  * Escape any metacharacters in the command.
 590                  */
 591                 esccmd = shell_quote(cmd);
 592                 if (esccmd == NULL)
 593                 {
 594                         fd = popen(cmd, "r");
 595                 } else
 596                 {
 597                         int len = strlen(shell) + strlen(esccmd) + 5;
 598                         scmd = (char *) ecalloc(len, sizeof(char));
 599                         SNPRINTF3(scmd, len, "%s %s %s", shell, shell_coption(), esccmd);
 600                         free(esccmd);
 601                         fd = popen(scmd, "r");
 602                         free(scmd);
 603                 }
 604         } else
 605 #endif
 606         {
 607                 fd = popen(cmd, "r");
 608         }
 609         /*
 610          * Redirection in `popen' might have messed with the
 611          * standard devices.  Restore binary input mode.
 612          */
 613         SET_BINARY(0);
 614         return (fd);
 615 }
 616
 617 #endif /* HAVE_POPEN */
 618
 619
 620 /*
 621  * Expand a filename, doing any system-specific metacharacter substitutions.
 622  */
 623         public char *
 624 lglob(filename)
 625         char *filename;
 626 {
 627         char *gfilename;
 628         char *ofilename;
 629
 630         ofilename = fexpand(filename);
 631         if (secure)
 632                 return (ofilename);
 633         filename = shell_unquote(ofilename);
 634
 635 #ifdef DECL_GLOB_LIST
 636 {
 637         /*
 638          * The globbing function returns a list of names.
 639          */
 640         int length;
 641         char *p;
 642         char *qfilename;
 643         DECL_GLOB_LIST(list)
 644
 645         GLOB_LIST(filename, list);
 646         if (GLOB_LIST_FAILED(list))
 647         {
 648                 free(filename);
 649                 return (ofilename);
 650         }
 651         length = 1; /* Room for trailing null byte */
 652         for (SCAN_GLOB_LIST(list, p))
 653         {
 654                 INIT_GLOB_LIST(list, p);
 655                 qfilename = shell_quote(p);
 656                 if (qfilename != NULL)
 657                 {
 658                         length += strlen(qfilename) + 1;
 659                         free(qfilename);
 660                 }
 661         }
 662         gfilename = (char *) ecalloc(length, sizeof(char));
 663         for (SCAN_GLOB_LIST(list, p))
 664         {
 665                 INIT_GLOB_LIST(list, p);
 666                 qfilename = shell_quote(p);
 667                 if (qfilename != NULL)
 668                 {
 669                         sprintf(gfilename + strlen(gfilename), "%s ", qfilename);
 670                         free(qfilename);
 671                 }
 672         }
 673         /*
 674          * Overwrite the final trailing space with a null terminator.
 675          */
 676         *--p = '\0';
 677         GLOB_LIST_DONE(list);
 678 }
 679 #else
 680 #ifdef DECL_GLOB_NAME
 681 {
 682         /*
 683          * The globbing function returns a single name, and
 684          * is called multiple times to walk thru all names.
 685          */
 686         register char *p;
 687         register int len;
 688         register int n;
 689         char *pathname;
 690         char *qpathname;
 691         DECL_GLOB_NAME(fnd,drive,dir,fname,ext,handle)
 692
 693         GLOB_FIRST_NAME(filename, &fnd, handle);
 694         if (GLOB_FIRST_FAILED(handle))
 695         {
 696                 free(filename);
 697                 return (ofilename);
 698         }
 699
 700         _splitpath(filename, drive, dir, fname, ext);
 701         len = 100;
 702         gfilename = (char *) ecalloc(len, sizeof(char));
 703         p = gfilename;
 704         do {
 705                 n = strlen(drive) + strlen(dir) + strlen(fnd.GLOB_NAME) + 1;
 706                 pathname = (char *) ecalloc(n, sizeof(char));
 707                 SNPRINTF3(pathname, n, "%s%s%s", drive, dir, fnd.GLOB_NAME);
 708                 qpathname = shell_quote(pathname);
 709                 free(pathname);
 710                 if (qpathname != NULL)
 711                 {
 712                         n = strlen(qpathname);
 713                         while (p - gfilename + n + 2 >= len)
 714                         {
 715                                 /*
 716                                  * No room in current buffer.
 717                                  * Allocate a bigger one.
 718                                  */
 719                                 len *= 2;
 720                                 *p = '\0';
 721                                 p = (char *) ecalloc(len, sizeof(char));
 722                                 strcpy(p, gfilename);
 723                                 free(gfilename);
 724                                 gfilename = p;
 725                                 p = gfilename + strlen(gfilename);
 726                         }
 727                         strcpy(p, qpathname);
 728                         free(qpathname);
 729                         p += n;
 730                         *p++ = ' ';
 731                 }
 732         } while (GLOB_NEXT_NAME(handle, &fnd) == 0);
 733
 734         /*
 735          * Overwrite the final trailing space with a null terminator.
 736          */
 737         *--p = '\0';
 738         GLOB_NAME_DONE(handle);
 739 }
 740 #else
 741 #if HAVE_POPEN
 742 {
 743         /*
 744          * We get the shell to glob the filename for us by passing
 745          * an "echo" command to the shell and reading its output.
 746          */
 747         FILE *fd;
 748         char *s;
 749         char *lessecho;
 750         char *cmd;
 751         char *esc;
 752         int len;
 753
 754         esc = get_meta_escape();
 755         if (strlen(esc) == 0)
 756                 esc = "-";
 757         esc = shell_quote(esc);
 758         if (esc == NULL)
 759         {
 760                 free(filename);
 761                 return (ofilename);
 762         }
 763         lessecho = lgetenv("LESSECHO");
 764         if (lessecho == NULL || *lessecho == '\0')
 765                 lessecho = "lessecho";
 766         /*
 767          * Invoke lessecho, and read its output (a globbed list of filenames).
 768          */
 769         len = strlen(lessecho) + strlen(ofilename) + (7*strlen(metachars())) + 24;
 770         cmd = (char *) ecalloc(len, sizeof(char));
 771         SNPRINTF4(cmd, len, "%s -p0x%x -d0x%x -e%s ", lessecho, openquote, closequote, esc);
 772         free(esc);
 773         for (s = metachars();  *s != '\0';  s++)
 774                 sprintf(cmd + strlen(cmd), "-n0x%x ", *s);
 775         sprintf(cmd + strlen(cmd), "-- %s", ofilename);
 776         fd = shellcmd(cmd);
 777         free(cmd);
 778         if (fd == NULL)
 779         {
 780                 /*
 781                  * Cannot create the pipe.
 782                  * Just return the original (fexpanded) filename.
 783                  */
 784                 free(filename);
 785                 return (ofilename);
 786         }
 787         gfilename = readfd(fd);
 788         pclose(fd);
 789         if (*gfilename == '\0')
 790         {
 791                 free(gfilename);
 792                 free(filename);
 793                 return (ofilename);
 794         }
 795 }
 796 #else
 797         /*
 798          * No globbing functions at all.  Just use the fexpanded filename.
 799          */
 800         gfilename = save(filename);
 801 #endif
 802 #endif
 803 #endif
 804         free(filename);
 805         free(ofilename);
 806         return (gfilename);
 807 }
 808
 809 /*
 810  * See if we should open a "replacement file"
 811  * instead of the file we're about to open.
 812  */
 813         public char *
 814 open_altfile(filename, pf, pfd)
 815         char *filename;
 816         int *pf;
 817         void **pfd;
 818 {
 819 #if !HAVE_POPEN
 820         return (NULL);
 821 #else
 822         char *lessopen;
 823         char *cmd;
 824         int len;
 825         FILE *fd;
 826 #if HAVE_FILENO
 827         int returnfd = 0;
 828 #endif
 829
 830         if (!use_lessopen || secure)
 831                 return (NULL);
 832         ch_ungetchar(-1);
 833         if ((lessopen = lgetenv("LESSOPEN")) == NULL)
 834                 return (NULL);
 835         if (*lessopen == '|')
 836         {
 837                 /*
 838                  * If LESSOPEN starts with a |, it indicates
 839                  * a "pipe preprocessor".
 840                  */
 841 #if !HAVE_FILENO
 842                 error("LESSOPEN pipe is not supported", NULL_PARG);
 843                 return (NULL);
 844 #else
 845                 lessopen++;
 846                 returnfd = 1;
 847 #endif
 848         }
 849         if (*lessopen == '-') {
 850                 /*
 851                  * Lessopen preprocessor will accept "-" as a filename.
 852                  */
 853                 lessopen++;
 854         } else {
 855                 if (strcmp(filename, "-") == 0)
 856                         return (NULL);
 857         }
 858
 859         len = strlen(lessopen) + strlen(filename) + 2;
 860         cmd = (char *) ecalloc(len, sizeof(char));
 861         SNPRINTF1(cmd, len, lessopen, filename);
 862         fd = shellcmd(cmd);
 863         free(cmd);
 864         if (fd == NULL)
 865         {
 866                 /*
 867                  * Cannot create the pipe.
 868                  */
 869                 return (NULL);
 870         }
 871 #if HAVE_FILENO
 872         if (returnfd)
 873         {
 874                 int f;
 875                 char c;
 876
 877                 /*
 878                  * Read one char to see if the pipe will produce any data.
 879                  * If it does, push the char back on the pipe.
 880                  */
 881                 f = fileno(fd);
 882                 SET_BINARY(f);
 883                 if (read(f, &c, 1) != 1)
 884                 {
 885                         /*
 886                          * Pipe is empty.  This means there is no alt file.
 887                          */
 888                         pclose(fd);
 889                         return (NULL);
 890                 }
 891                 ch_ungetchar(c);
 892                 *pfd = (void *) fd;
 893                 *pf = f;
 894                 return (save("-"));
 895         }
 896 #endif
 897         cmd = readfd(fd);
 898         pclose(fd);
 899         if (*cmd == '\0')
 900                 /*
 901                  * Pipe is empty.  This means there is no alt file.
 902                  */
 903                 return (NULL);
 904         return (cmd);
 905 #endif /* HAVE_POPEN */
 906 }
 907
 908 /*
 909  * Close a replacement file.
 910  */
 911         public void
 912 close_altfile(altfilename, filename, pipefd)
 913         char *altfilename;
 914         char *filename;
 915         void *pipefd;
 916 {
 917 #if HAVE_POPEN
 918         char *lessclose;
 919         FILE *fd;
 920         char *cmd;
 921         int len;
 922
 923         if (secure)
 924                 return;
 925         if (pipefd != NULL)
 926         {
 927 #if OS2
 928                 /*
 929                  * The pclose function of OS/2 emx sometimes fails.
 930                  * Send SIGINT to the piped process before closing it.
 931                  */
 932                 kill(((FILE*)pipefd)->_pid, SIGINT);
 933 #endif
 934                 pclose((FILE*) pipefd);
 935         }
 936         if ((lessclose = lgetenv("LESSCLOSE")) == NULL)
 937                 return;
 938         len = strlen(lessclose) + strlen(filename) + strlen(altfilename) + 2;
 939         cmd = (char *) ecalloc(len, sizeof(char));
 940         SNPRINTF2(cmd, len, lessclose, filename, altfilename);
 941         fd = shellcmd(cmd);
 942         free(cmd);
 943         if (fd != NULL)
 944                 pclose(fd);
 945 #endif
 946 }
 947
 948 /*
 949  * Is the specified file a directory?
 950  */
 951         public int
 952 is_dir(filename)
 953         char *filename;
 954 {
 955         int isdir = 0;
 956
 957         filename = shell_unquote(filename);
 958 #if HAVE_STAT
 959 {
 960         int r;
 961         struct stat statbuf;
 962
 963         r = stat(filename, &statbuf);
 964         isdir = (r >= 0 && S_ISDIR(statbuf.st_mode));
 965 }
 966 #else
 967 #ifdef _OSK
 968 {
 969         register int f;
 970
 971         f = open(filename, S_IREAD | S_IFDIR);
 972         if (f >= 0)
 973                 close(f);
 974         isdir = (f >= 0);
 975 }
 976 #endif
 977 #endif
 978         free(filename);
 979         return (isdir);
 980 }
 981
 982 /*
 983  * Returns NULL if the file can be opened and
 984  * is an ordinary file, otherwise an error message
 985  * (if it cannot be opened or is a directory, etc.)
 986  */
 987         public char *
 988 bad_file(filename)
 989         char *filename;
 990 {
 991         register char *m = NULL;
 992
 993         filename = shell_unquote(filename);
 994         if (!force_open && is_dir(filename))
 995         {
 996                 static char is_a_dir[] = " is a directory";
 997
 998                 m = (char *) ecalloc(strlen(filename) + sizeof(is_a_dir),
 999                         sizeof(char));
1000                 strcpy(m, filename);
1001                 strcat(m, is_a_dir);
1002         } else
1003         {
1004 #if HAVE_STAT
1005                 int r;
1006                 struct stat statbuf;
1007
1008                 r = stat(filename, &statbuf);
1009                 if (r < 0)
1010                 {
1011                         m = errno_message(filename);
1012                 } else if (force_open)
1013                 {
1014                         m = NULL;
1015                 } else if (!S_ISREG(statbuf.st_mode))
1016                 {
1017                         static char not_reg[] = " is not a regular file (use -f to see it)";
1018                         m = (char *) ecalloc(strlen(filename) + sizeof(not_reg),
1019                                 sizeof(char));
1020                         strcpy(m, filename);
1021                         strcat(m, not_reg);
1022                 }
1023 #endif
1024         }
1025         free(filename);
1026         return (m);
1027 }
1028
1029 /*
1030  * Return the size of a file, as cheaply as possible.
1031  * In Unix, we can stat the file.
1032  */
1033         public POSITION
1034 filesize(f)
1035         int f;
1036 {
1037 #if HAVE_STAT
1038         struct stat statbuf;
1039
1040         if (fstat(f, &statbuf) >= 0)
1041                 return ((POSITION) statbuf.st_size);
1042 #else
1043 #ifdef _OSK
1044         long size;
1045
1046         if ((size = (long) _gs_size(f)) >= 0)
1047                 return ((POSITION) size);
1048 #endif
1049 #endif
1050         return (seek_filesize(f));
1051 }
1052
1053 /*
1054  *
1055  */
1056         public char *
1057 shell_coption()
1058 {
1059         return ("-c");
1060 }
1061
1062 /*
1063  * Return last component of a pathname.
1064  */
1065         public char *
1066 last_component(name)
1067         char *name;
1068 {
1069         char *slash;
1070
1071         for (slash = name + strlen(name);  slash > name; )
1072         {
1073                 --slash;
1074                 if (*slash == *PATHNAME_SEP || *slash == '/')
1075                         return (slash + 1);
1076         }
1077         return (name);
1078 }
1079