src/termcap.c

   1 /* Work-alike for termcap, plus extra features.
   2    Copyright (C) 1985, 1986, 1993, 1994, 1995, 2000, 2001, 2002, 2003,
   3                  2004, 2005, 2006, 2007, 2008, 2011 Free Software Foundation, Inc.
   4
   5 This program is free software; you can redistribute it and/or modify
   6 it under the terms of the GNU General Public License as published by
   7 the Free Software Foundation; either version 2, or (at your option)
   8 any later version.
   9
  10 This program is distributed in the hope that it will be useful,
  11 but WITHOUT ANY WARRANTY; without even the implied warranty of
  12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13 GNU General Public License for more details.
  14
  15 You should have received a copy of the GNU General Public License
  16 along with this program; see the file COPYING.  If not, write to
  17 the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  18 Boston, MA 02110-1301, USA.  */
  19
  20 /* Emacs config.h may rename various library functions such as malloc.  */
  21 #include <config.h>
  22 #include <setjmp.h>
  23 #include <sys/file.h>
  24 #include <fcntl.h>
  25 #include <unistd.h>
  26
  27 #include "lisp.h"
  28 #include "tparam.h"
  29 #ifdef MSDOS
  30 #include "msdos.h"
  31 #endif
  32
  33 #ifndef NULL
  34 #define NULL (char *) 0
  35 #endif
  36
  37 /* BUFSIZE is the initial size allocated for the buffer
  38    for reading the termcap file.
  39    It is not a limit.
  40    Make it large normally for speed.
  41    Make it variable when debugging, so can exercise
  42    increasing the space dynamically.  */
  43
  44 #ifndef BUFSIZE
  45 #ifdef DEBUG
  46 #define BUFSIZE bufsize
  47
  48 int bufsize = 128;
  49 #else
  50 #define BUFSIZE 2048
  51 #endif
  52 #endif
  53
  54 #ifndef TERMCAP_FILE
  55 #define TERMCAP_FILE "/etc/termcap"
  56 #endif
  57
  58 \f
  59 /* Looking up capabilities in the entry already found.  */
  60
  61 /* The pointer to the data made by tgetent is left here
  62    for tgetnum, tgetflag and tgetstr to find.  */
  63 static char *term_entry;
  64
  65 static char *tgetst1 (char *ptr, char **area);
  66
  67 /* Search entry BP for capability CAP.
  68    Return a pointer to the capability (in BP) if found,
  69    0 if not found.  */
  70
  71 static char *
  72 find_capability (register char *bp, register const char *cap)
  73 {
  74   for (; *bp; bp++)
  75     if (bp[0] == ':'
  76         && bp[1] == cap[0]
  77         && bp[2] == cap[1])
  78       return &bp[4];
  79   return NULL;
  80 }
  81
  82 int
  83 tgetnum (const char *cap)
  84 {
  85   register char *ptr = find_capability (term_entry, cap);
  86   if (!ptr || ptr[-1] != '#')
  87     return -1;
  88   return atoi (ptr);
  89 }
  90
  91 int
  92 tgetflag (const char *cap)
  93 {
  94   register char *ptr = find_capability (term_entry, cap);
  95   return ptr && ptr[-1] == ':';
  96 }
  97
  98 /* Look up a string-valued capability CAP.
  99    If AREA is non-null, it points to a pointer to a block in which
 100    to store the string.  That pointer is advanced over the space used.
 101    If AREA is null, space is allocated with `malloc'.  */
 102
 103 char *
 104 tgetstr (const char *cap, char **area)
 105 {
 106   register char *ptr = find_capability (term_entry, cap);
 107   if (!ptr || (ptr[-1] != '=' && ptr[-1] != '~'))
 108     return NULL;
 109   return tgetst1 (ptr, area);
 110 }
 111
 112 #ifdef IS_EBCDIC_HOST
 113 /* Table, indexed by a character in range 0200 to 0300 with 0200 subtracted,
 114    gives meaning of character following \, or a space if no special meaning.
 115    Sixteen characters per line within the string.  */
 116
 117 static const char esctab[]
 118   = " \057\026  \047\014         \
 119      \025   \015      \
 120    \005 \013          \
 121                 ";
 122 #else
 123 /* Table, indexed by a character in range 0100 to 0140 with 0100 subtracted,
 124    gives meaning of character following \, or a space if no special meaning.
 125    Eight characters per line within the string.  */
 126
 127 static const char esctab[]
 128   = " \007\010  \033\014 \
 129       \012 \
 130   \015 \011 \013 \
 131         ";
 132 #endif
 133
 134 /* PTR points to a string value inside a termcap entry.
 135    Copy that value, processing \ and ^ abbreviations,
 136    into the block that *AREA points to,
 137    or to newly allocated storage if AREA is NULL.
 138    Return the address to which we copied the value,
 139    or NULL if PTR is NULL.  */
 140
 141 static char *
 142 tgetst1 (char *ptr, char **area)
 143 {
 144   register char *p, *r;
 145   register int c;
 146   register int size;
 147   char *ret;
 148   register int c1;
 149
 150   if (!ptr)
 151     return NULL;
 152
 153   /* `ret' gets address of where to store the string.  */
 154   if (!area)
 155     {
 156       /* Compute size of block needed (may overestimate).  */
 157       p = ptr;
 158       while ((c = *p++) && c != ':' && c != '\n')
 159         ;
 160       ret = (char *) xmalloc (p - ptr + 1);
 161     }
 162   else
 163     ret = *area;
 164
 165   /* Copy the string value, stopping at null or colon.
 166      Also process ^ and \ abbreviations.  */
 167   p = ptr;
 168   r = ret;
 169   while ((c = *p++) && c != ':' && c != '\n')
 170     {
 171       if (c == '^')
 172         {
 173           c = *p++;
 174           if (c == '?')
 175             c = 0177;
 176           else
 177             c &= 037;
 178         }
 179       else if (c == '\\')
 180         {
 181           c = *p++;
 182           if (c >= '0' && c <= '7')
 183             {
 184               c -= '0';
 185               size = 0;
 186
 187               while (++size < 3 && (c1 = *p) >= '0' && c1 <= '7')
 188                 {
 189                   c *= 8;
 190                   c += c1 - '0';
 191                   p++;
 192                 }
 193             }
 194 #ifdef IS_EBCDIC_HOST
 195           else if (c >= 0200 && c < 0360)
 196             {
 197               c1 = esctab[(c & ~0100) - 0200];
 198               if (c1 != ' ')
 199                 c = c1;
 200             }
 201 #else
 202           else if (c >= 0100 && c < 0200)
 203             {
 204               c1 = esctab[(c & ~040) - 0100];
 205               if (c1 != ' ')
 206                 c = c1;
 207             }
 208 #endif
 209         }
 210       *r++ = c;
 211     }
 212
 213   /* Sometimes entries have "%pN" which means use parameter N in the
 214      next %-substitution.  If all such N are continuous in the range
 215      [1,9] we can remove each "%pN" because they are redundant, thus
 216      reducing bandwidth requirements.  True, Emacs is well beyond the
 217      days of 150baud teletypes, but some of its users aren't much so.
 218
 219      This pass could probably be integrated into the one above but
 220      abbreviation expansion makes that effort a little more hairy than
 221      its worth; this is cleaner.  */
 222   {
 223     register int last_p_param = 0;
 224     int remove_p_params = 1;
 225     struct { char *beg; int len; } cut[11];
 226
 227     for (cut[0].beg = p = ret; p < r - 3; p++)
 228       {
 229         if (!remove_p_params)
 230           break;
 231         if (*p == '%' && *(p + 1) == 'p')
 232           {
 233             if (*(p + 2) - '0' == 1 + last_p_param)
 234               {
 235                 cut[last_p_param].len = p - cut[last_p_param].beg;
 236                 last_p_param++;
 237                 p += 3;
 238                 cut[last_p_param].beg = p;
 239               }
 240             else                                /* not continuous: bail */
 241               remove_p_params = 0;
 242             if (last_p_param > 10)              /* too many: bail */
 243               remove_p_params = 0;
 244           }
 245       }
 246     if (remove_p_params && last_p_param)
 247       {
 248         register int i;
 249         char *wp;
 250
 251         cut[last_p_param].len = r - cut[last_p_param].beg;
 252         for (i = 0, wp = ret; i <= last_p_param; wp += cut[i++].len)
 253           memcpy (wp, cut[i].beg, cut[i].len);
 254         r = wp;
 255       }
 256   }
 257
 258   *r = '\0';
 259   /* Update *AREA.  */
 260   if (area)
 261     *area = r + 1;
 262   return ret;
 263 }
 264 \f
 265 /* Outputting a string with padding.  */
 266
 267 char PC;
 268
 269 void
 270 tputs (register const char *str, int nlines, int (*outfun) (int))
 271 {
 272   register int padcount = 0;
 273   register int speed;
 274
 275   speed = baud_rate;
 276   /* For quite high speeds, convert to the smaller
 277      units to avoid overflow.  */
 278   if (speed > 10000)
 279     speed = - speed / 100;
 280
 281   if (!str)
 282     return;
 283
 284   while (*str >= '0' && *str <= '9')
 285     {
 286       padcount += *str++ - '0';
 287       padcount *= 10;
 288     }
 289   if (*str == '.')
 290     {
 291       str++;
 292       padcount += *str++ - '0';
 293     }
 294   if (*str == '*')
 295     {
 296       str++;
 297       padcount *= nlines;
 298     }
 299   while (*str)
 300     (*outfun) (*str++);
 301
 302   /* PADCOUNT is now in units of tenths of msec.
 303      SPEED is measured in characters per 10 seconds
 304      or in characters per .1 seconds (if negative).
 305      We use the smaller units for larger speeds to avoid overflow.  */
 306   padcount *= speed;
 307   padcount += 500;
 308   padcount /= 1000;
 309   if (speed < 0)
 310     padcount = -padcount;
 311   else
 312     {
 313       padcount += 50;
 314       padcount /= 100;
 315     }
 316
 317   while (padcount-- > 0)
 318     (*outfun) (PC);
 319 }
 320 \f
 321 /* Finding the termcap entry in the termcap data base.  */
 322
 323 struct termcap_buffer
 324   {
 325     char *beg;
 326     ptrdiff_t size;
 327     char *ptr;
 328     int ateof;
 329     ptrdiff_t full;
 330   };
 331
 332 /* Forward declarations of static functions.  */
 333
 334 static int scan_file (char *str, int fd, register struct termcap_buffer *bufp);
 335 static char *gobble_line (int fd, register struct termcap_buffer *bufp, char *append_end);
 336 static int compare_contin (register char *str1, register char *str2);
 337 static int name_match (char *line, char *name);
 338
 339 #ifdef MSDOS /* MW, May 1993 */
 340 static int
 341 valid_filename_p (char *fn)
 342 {
 343   return *fn == '/' || fn[1] == ':';
 344 }
 345 #else
 346 #define valid_filename_p(fn) (*(fn) == '/')
 347 #endif
 348
 349 /* Find the termcap entry data for terminal type NAME
 350    and store it in the block that BP points to.
 351    Record its address for future use.
 352
 353    If BP is null, space is dynamically allocated.
 354
 355    Return -1 if there is some difficulty accessing the data base
 356    of terminal types,
 357    0 if the data base is accessible but the type NAME is not defined
 358    in it, and some other value otherwise.  */
 359
 360 int
 361 tgetent (char *bp, const char *name)
 362 {
 363   register char *termcap_name;
 364   register int fd;
 365   struct termcap_buffer buf;
 366   register char *bp1;
 367   char *tc_search_point;
 368   char *term;
 369   ptrdiff_t malloc_size = 0;
 370   register int c;
 371   char *tcenv = NULL;           /* TERMCAP value, if it contains :tc=.  */
 372   char *indirect = NULL;        /* Terminal type in :tc= in TERMCAP value.  */
 373   int filep;
 374
 375 #ifdef INTERNAL_TERMINAL
 376   /* For the internal terminal we don't want to read any termcap file,
 377      so fake it.  */
 378   if (!strcmp (name, "internal"))
 379     {
 380       term = INTERNAL_TERMINAL;
 381       if (!bp)
 382         {
 383           malloc_size = 1 + strlen (term);
 384           bp = (char *) xmalloc (malloc_size);
 385         }
 386       strcpy (bp, term);
 387       goto ret;
 388     }
 389 #endif /* INTERNAL_TERMINAL */
 390
 391   /* For compatibility with programs like `less' that want to
 392      put data in the termcap buffer themselves as a fallback.  */
 393   if (bp)
 394     term_entry = bp;
 395
 396   termcap_name = getenv ("TERMCAP");
 397   if (termcap_name && *termcap_name == '\0')
 398     termcap_name = NULL;
 399 #if defined (MSDOS) && !defined (TEST)
 400   if (termcap_name && (*termcap_name == '\\'
 401                        || *termcap_name == '/'
 402                        || termcap_name[1] == ':'))
 403     dostounix_filename (termcap_name);
 404 #endif
 405
 406   filep = termcap_name && valid_filename_p (termcap_name);
 407
 408   /* If termcap_name is non-null and starts with / (in the un*x case, that is),
 409      it is a file name to use instead of /etc/termcap.
 410      If it is non-null and does not start with /,
 411      it is the entry itself, but only if
 412      the name the caller requested matches the TERM variable.  */
 413
 414   if (termcap_name && !filep && !strcmp (name, getenv ("TERM")))
 415     {
 416       indirect = tgetst1 (find_capability (termcap_name, "tc"), (char **) 0);
 417       if (!indirect)
 418         {
 419           if (!bp)
 420             bp = termcap_name;
 421           else
 422             strcpy (bp, termcap_name);
 423           goto ret;
 424         }
 425       else
 426         {                       /* It has tc=.  Need to read /etc/termcap.  */
 427           tcenv = termcap_name;
 428           termcap_name = NULL;
 429         }
 430     }
 431
 432   if (!termcap_name || !filep)
 433     termcap_name = TERMCAP_FILE;
 434
 435   /* Here we know we must search a file and termcap_name has its name.  */
 436
 437 #ifdef MSDOS
 438   fd = open (termcap_name, O_RDONLY|O_TEXT, 0);
 439 #else
 440   fd = open (termcap_name, O_RDONLY, 0);
 441 #endif
 442   if (fd < 0)
 443     return -1;
 444
 445   buf.size = BUFSIZE;
 446   /* Add 1 to size to ensure room for terminating null.  */
 447   buf.beg = (char *) xmalloc (buf.size + 1);
 448   term = indirect ? indirect : (char *)name;
 449
 450   if (!bp)
 451     {
 452       malloc_size = indirect ? strlen (tcenv) + 1 : buf.size;
 453       bp = (char *) xmalloc (malloc_size);
 454     }
 455   tc_search_point = bp1 = bp;
 456
 457   if (indirect)
 458     /* Copy the data from the environment variable.  */
 459     {
 460       strcpy (bp, tcenv);
 461       bp1 += strlen (tcenv);
 462     }
 463
 464   while (term)
 465     {
 466       /* Scan the file, reading it via buf, till find start of main entry.  */
 467       if (scan_file (term, fd, &buf) == 0)
 468         {
 469           close (fd);
 470           xfree (buf.beg);
 471           if (malloc_size)
 472             xfree (bp);
 473           return 0;
 474         }
 475
 476       /* Free old `term' if appropriate.  */
 477       if (term != name)
 478         xfree (term);
 479
 480       /* If BP is malloc'd by us, make sure it is big enough.  */
 481       if (malloc_size)
 482         {
 483           ptrdiff_t offset1 = bp1 - bp, offset2 = tc_search_point - bp;
 484           malloc_size = offset1 + buf.size;
 485           bp = termcap_name = (char *) xrealloc (bp, malloc_size);
 486           bp1 = termcap_name + offset1;
 487           tc_search_point = termcap_name + offset2;
 488         }
 489
 490       /* Copy the line of the entry from buf into bp.  */
 491       termcap_name = buf.ptr;
 492       while ((*bp1++ = c = *termcap_name++) && c != '\n')
 493         /* Drop out any \ newline sequence.  */
 494         if (c == '\\' && *termcap_name == '\n')
 495           {
 496             bp1--;
 497             termcap_name++;
 498           }
 499       *bp1 = '\0';
 500
 501       /* Does this entry refer to another terminal type's entry?
 502          If something is found, copy it into heap and null-terminate it.  */
 503       tc_search_point = find_capability (tc_search_point, "tc");
 504       term = tgetst1 (tc_search_point, (char **) 0);
 505     }
 506
 507   close (fd);
 508   xfree (buf.beg);
 509
 510   if (malloc_size)
 511     bp = (char *) xrealloc (bp, bp1 - bp + 1);
 512
 513  ret:
 514   term_entry = bp;
 515   return 1;
 516 }
 517
 518 /* Given file open on FD and buffer BUFP,
 519    scan the file from the beginning until a line is found
 520    that starts the entry for terminal type STR.
 521    Return 1 if successful, with that line in BUFP,
 522    or 0 if no entry is found in the file.  */
 523
 524 static int
 525 scan_file (char *str, int fd, register struct termcap_buffer *bufp)
 526 {
 527   register char *end;
 528
 529   bufp->ptr = bufp->beg;
 530   bufp->full = 0;
 531   bufp->ateof = 0;
 532   *bufp->ptr = '\0';
 533
 534   lseek (fd, 0L, 0);
 535
 536   while (!bufp->ateof)
 537     {
 538       /* Read a line into the buffer.  */
 539       end = NULL;
 540       do
 541         {
 542           /* if it is continued, append another line to it,
 543              until a non-continued line ends.  */
 544           end = gobble_line (fd, bufp, end);
 545         }
 546       while (!bufp->ateof && end[-2] == '\\');
 547
 548       if (*bufp->ptr != '#'
 549           && name_match (bufp->ptr, str))
 550         return 1;
 551
 552       /* Discard the line just processed.  */
 553       bufp->ptr = end;
 554     }
 555   return 0;
 556 }
 557
 558 /* Return nonzero if NAME is one of the names specified
 559    by termcap entry LINE.  */
 560
 561 static int
 562 name_match (char *line, char *name)
 563 {
 564   register char *tem;
 565
 566   if (!compare_contin (line, name))
 567     return 1;
 568   /* This line starts an entry.  Is it the right one?  */
 569   for (tem = line; *tem && *tem != '\n' && *tem != ':'; tem++)
 570     if (*tem == '|' && !compare_contin (tem + 1, name))
 571       return 1;
 572
 573   return 0;
 574 }
 575
 576 static int
 577 compare_contin (register char *str1, register char *str2)
 578 {
 579   register int c1, c2;
 580   while (1)
 581     {
 582       c1 = *str1++;
 583       c2 = *str2++;
 584       while (c1 == '\\' && *str1 == '\n')
 585         {
 586           str1++;
 587           while ((c1 = *str1++) == ' ' || c1 == '\t');
 588         }
 589       if (c2 == '\0')
 590         {
 591           /* End of type being looked up.  */
 592           if (c1 == '|' || c1 == ':')
 593             /* If end of name in data base, we win.  */
 594             return 0;
 595           else
 596             return 1;
 597         }
 598       else if (c1 != c2)
 599         return 1;
 600     }
 601 }
 602
 603 /* Make sure that the buffer <- BUFP contains a full line
 604    of the file open on FD, starting at the place BUFP->ptr
 605    points to.  Can read more of the file, discard stuff before
 606    BUFP->ptr, or make the buffer bigger.
 607
 608    Return the pointer to after the newline ending the line,
 609    or to the end of the file, if there is no newline to end it.
 610
 611    Can also merge on continuation lines.  If APPEND_END is
 612    non-null, it points past the newline of a line that is
 613    continued; we add another line onto it and regard the whole
 614    thing as one line.  The caller decides when a line is continued.  */
 615
 616 static char *
 617 gobble_line (int fd, register struct termcap_buffer *bufp, char *append_end)
 618 {
 619   register char *end;
 620   register int nread;
 621   register char *buf = bufp->beg;
 622
 623   if (!append_end)
 624     append_end = bufp->ptr;
 625
 626   while (1)
 627     {
 628       end = append_end;
 629       while (*end && *end != '\n') end++;
 630       if (*end)
 631         break;
 632       if (bufp->ateof)
 633         return buf + bufp->full;
 634       if (bufp->ptr == buf)
 635         {
 636           if (bufp->full == bufp->size)
 637             {
 638               ptrdiff_t ptr_offset = bufp->ptr - buf;
 639               ptrdiff_t append_end_offset = append_end - buf;
 640               /* Add 1 to size to ensure room for terminating null.  */
 641               ptrdiff_t size = bufp->size + 1;
 642               bufp->beg = buf = xpalloc (buf, &size, 1, -1, 1);
 643               bufp->size = size - 1;
 644               bufp->ptr = buf + ptr_offset;
 645               append_end = buf + append_end_offset;
 646             }
 647         }
 648       else
 649         {
 650           append_end -= bufp->ptr - buf;
 651           memcpy (buf, bufp->ptr, bufp->full -= bufp->ptr - buf);
 652           bufp->ptr = buf;
 653         }
 654       if (!(nread = read (fd, buf + bufp->full, bufp->size - bufp->full)))
 655         bufp->ateof = 1;
 656       bufp->full += nread;
 657       buf[bufp->full] = '\0';
 658     }
 659   return end + 1;
 660 }
 661 \f
 662 #ifdef TEST
 663
 664 #ifdef NULL
 665 #undef NULL
 666 #endif
 667
 668 #include <stdio.h>
 669
 670 static void
 671 tprint (char *cap)
 672 {
 673   char *x = tgetstr (cap, 0);
 674   register char *y;
 675
 676   printf ("%s: ", cap);
 677   if (x)
 678     {
 679       for (y = x; *y; y++)
 680         if (*y <= ' ' || *y == 0177)
 681           printf ("\\%0o", *y);
 682         else
 683           putchar (*y);
 684       free (x);
 685     }
 686   else
 687     printf ("none");
 688   putchar ('\n');
 689 }
 690
 691 int
 692 main (int argc, char **argv)
 693 {
 694   char *term;
 695   char *buf;
 696
 697   term = argv[1];
 698   printf ("TERM: %s\n", term);
 699
 700   buf = (char *) tgetent (0, term);
 701   if ((int) buf <= 0)
 702     {
 703       printf ("No entry.\n");
 704       return 0;
 705     }
 706
 707   printf ("Entry: %s\n", buf);
 708
 709   tprint ("cm");
 710   tprint ("AL");
 711
 712   printf ("co: %d\n", tgetnum ("co"));
 713   printf ("am: %d\n", tgetflag ("am"));
 714
 715   return 0;
 716 }
 717
 718 #endif /* TEST */