src/termcap.c

   1 /* Work-alike for termcap, plus extra features.
   2    Copyright (C) 1985-1986, 1993-1995, 2000-2008, 2011, 2013-2017 Free
   3    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.  If not, see <http://www.gnu.org/licenses/>.  */
  17
  18 /* Emacs config.h may rename various library functions such as malloc.  */
  19 #include <config.h>
  20 #include <sys/file.h>
  21 #include <fcntl.h>
  22 #include <unistd.h>
  23
  24 #include "lisp.h"
  25 #include "tparam.h"
  26 #ifdef MSDOS
  27 #include "msdos.h"
  28 #endif
  29
  30 /* BUFSIZE is the initial size allocated for the buffer
  31    for reading the termcap file.
  32    It is not a limit.
  33    Make it large normally for speed.
  34    Make it variable when debugging, so can exercise
  35    increasing the space dynamically.  */
  36
  37 #ifndef BUFSIZE
  38 #ifdef DEBUG
  39 #define BUFSIZE bufsize
  40
  41 int bufsize = 128;
  42 #else
  43 #define BUFSIZE 2048
  44 #endif
  45 #endif
  46
  47 #ifndef TERMCAP_FILE
  48 #define TERMCAP_FILE "/etc/termcap"
  49 #endif
  50
  51 \f
  52 /* Looking up capabilities in the entry already found.  */
  53
  54 /* The pointer to the data made by tgetent is left here
  55    for tgetnum, tgetflag and tgetstr to find.  */
  56 static char *term_entry;
  57
  58 static char *tgetst1 (char *ptr, char **area);
  59
  60 /* Search entry BP for capability CAP.
  61    Return a pointer to the capability (in BP) if found,
  62    0 if not found.  */
  63
  64 static char *
  65 find_capability (register char *bp, register const char *cap)
  66 {
  67   for (; *bp; bp++)
  68     if (bp[0] == ':'
  69         && bp[1] == cap[0]
  70         && bp[2] == cap[1])
  71       return &bp[4];
  72   return NULL;
  73 }
  74
  75 int
  76 tgetnum (const char *cap)
  77 {
  78   register char *ptr = find_capability (term_entry, cap);
  79   if (!ptr || ptr[-1] != '#')
  80     return -1;
  81   return atoi (ptr);
  82 }
  83
  84 int
  85 tgetflag (const char *cap)
  86 {
  87   register char *ptr = find_capability (term_entry, cap);
  88   return ptr && ptr[-1] == ':';
  89 }
  90
  91 /* Look up a string-valued capability CAP.
  92    If AREA is non-null, it points to a pointer to a block in which
  93    to store the string.  That pointer is advanced over the space used.
  94    If AREA is null, space is allocated with `malloc'.  */
  95
  96 char *
  97 tgetstr (const char *cap, char **area)
  98 {
  99   register char *ptr = find_capability (term_entry, cap);
 100   if (!ptr || (ptr[-1] != '=' && ptr[-1] != '~'))
 101     return NULL;
 102   return tgetst1 (ptr, area);
 103 }
 104
 105 #ifdef IS_EBCDIC_HOST
 106 /* Table, indexed by a character in range 0200 to 0300 with 0200 subtracted,
 107    gives meaning of character following \, or a space if no special meaning.
 108    Sixteen characters per line within the string.  */
 109
 110 static const char esctab[]
 111   = " \057\026  \047\014         \
 112      \025   \015      \
 113    \005 \013          \
 114                 ";
 115 #else
 116 /* Table, indexed by a character in range 0100 to 0140 with 0100 subtracted,
 117    gives meaning of character following \, or a space if no special meaning.
 118    Eight characters per line within the string.  */
 119
 120 static const char esctab[]
 121   = " \007\010  \033\014 \
 122       \012 \
 123   \015 \011 \013 \
 124         ";
 125 #endif
 126
 127 /* PTR points to a string value inside a termcap entry.
 128    Copy that value, processing \ and ^ abbreviations,
 129    into the block that *AREA points to,
 130    or to newly allocated storage if AREA is NULL.
 131    Return the address to which we copied the value,
 132    or NULL if PTR is NULL.  */
 133
 134 static char *
 135 tgetst1 (char *ptr, char **area)
 136 {
 137   register char *p, *r;
 138   register int c;
 139   register int size;
 140   char *ret;
 141   register int c1;
 142
 143   if (!ptr)
 144     return NULL;
 145
 146   /* `ret' gets address of where to store the string.  */
 147   if (!area)
 148     {
 149       /* Compute size of block needed (may overestimate).  */
 150       p = ptr;
 151       while ((c = *p++) && c != ':' && c != '\n')
 152         ;
 153       ret = xmalloc (p - ptr + 1);
 154     }
 155   else
 156     ret = *area;
 157
 158   /* Copy the string value, stopping at null or colon.
 159      Also process ^ and \ abbreviations.  */
 160   p = ptr;
 161   r = ret;
 162   while ((c = *p++) && c != ':' && c != '\n')
 163     {
 164       if (c == '^')
 165         {
 166           c = *p++;
 167           if (c == '?')
 168             c = 0177;
 169           else
 170             c &= 037;
 171         }
 172       else if (c == '\\')
 173         {
 174           c = *p++;
 175           if (c >= '0' && c <= '7')
 176             {
 177               c -= '0';
 178               size = 0;
 179
 180               while (++size < 3 && (c1 = *p) >= '0' && c1 <= '7')
 181                 {
 182                   c *= 8;
 183                   c += c1 - '0';
 184                   p++;
 185                 }
 186             }
 187 #ifdef IS_EBCDIC_HOST
 188           else if (c >= 0200 && c < 0360)
 189             {
 190               c1 = esctab[(c & ~0100) - 0200];
 191               if (c1 != ' ')
 192                 c = c1;
 193             }
 194 #else
 195           else if (c >= 0100 && c < 0200)
 196             {
 197               c1 = esctab[(c & ~040) - 0100];
 198               if (c1 != ' ')
 199                 c = c1;
 200             }
 201 #endif
 202         }
 203       *r++ = c;
 204     }
 205
 206   /* Sometimes entries have "%pN" which means use parameter N in the
 207      next %-substitution.  If all such N are continuous in the range
 208      [1,9] we can remove each "%pN" because they are redundant, thus
 209      reducing bandwidth requirements.  True, Emacs is well beyond the
 210      days of 150baud teletypes, but some of its users aren't much so.
 211
 212      This pass could probably be integrated into the one above but
 213      abbreviation expansion makes that effort a little more hairy than
 214      its worth; this is cleaner.  */
 215   {
 216     int last_p_param = 0;
 217     bool remove_p_params = 1;
 218     struct { char *beg; int len; } cut[11];
 219
 220     for (cut[0].beg = p = ret; p < r - 3; p++)
 221       {
 222         if (!remove_p_params)
 223           break;
 224         if (*p == '%' && *(p + 1) == 'p')
 225           {
 226             if (*(p + 2) - '0' == 1 + last_p_param)
 227               {
 228                 cut[last_p_param].len = p - cut[last_p_param].beg;
 229                 last_p_param++;
 230                 p += 3;
 231                 cut[last_p_param].beg = p;
 232               }
 233             else                                /* not continuous: bail */
 234               remove_p_params = 0;
 235             if (last_p_param > 10)              /* too many: bail */
 236               remove_p_params = 0;
 237           }
 238       }
 239     if (remove_p_params && last_p_param)
 240       {
 241         register int i;
 242         char *wp;
 243
 244         cut[last_p_param].len = r - cut[last_p_param].beg;
 245         for (i = 0, wp = ret; i <= last_p_param; wp += cut[i++].len)
 246           memcpy (wp, cut[i].beg, cut[i].len);
 247         r = wp;
 248       }
 249   }
 250
 251   *r = '\0';
 252   /* Update *AREA.  */
 253   if (area)
 254     *area = r + 1;
 255   return ret;
 256 }
 257 \f
 258 /* Outputting a string with padding.  */
 259
 260 char PC;
 261
 262 void
 263 tputs (register const char *str, int nlines, int (*outfun) (int))
 264 {
 265   register int padcount = 0;
 266   register int speed;
 267
 268   speed = baud_rate;
 269   /* For quite high speeds, convert to the smaller
 270      units to avoid overflow.  */
 271   if (speed > 10000)
 272     speed = - speed / 100;
 273
 274   if (!str)
 275     return;
 276
 277   while (*str >= '0' && *str <= '9')
 278     {
 279       padcount += *str++ - '0';
 280       padcount *= 10;
 281     }
 282   if (*str == '.')
 283     {
 284       str++;
 285       padcount += *str++ - '0';
 286     }
 287   if (*str == '*')
 288     {
 289       str++;
 290       padcount *= nlines;
 291     }
 292   while (*str)
 293     (*outfun) (*str++);
 294
 295   /* PADCOUNT is now in units of tenths of msec.
 296      SPEED is measured in characters per 10 seconds
 297      or in characters per .1 seconds (if negative).
 298      We use the smaller units for larger speeds to avoid overflow.  */
 299   padcount *= speed;
 300   padcount += 500;
 301   padcount /= 1000;
 302   if (speed < 0)
 303     padcount = -padcount;
 304   else
 305     {
 306       padcount += 50;
 307       padcount /= 100;
 308     }
 309
 310   while (padcount-- > 0)
 311     (*outfun) (PC);
 312 }
 313 \f
 314 /* Finding the termcap entry in the termcap data base.  */
 315
 316 struct termcap_buffer
 317   {
 318     char *beg;
 319     ptrdiff_t size;
 320     char *ptr;
 321     bool ateof;
 322     ptrdiff_t full;
 323   };
 324
 325 /* Forward declarations of static functions.  */
 326
 327 static bool scan_file (char *, int, struct termcap_buffer *);
 328 static char *gobble_line (int, struct termcap_buffer *, char *);
 329 static bool compare_contin (char *, char *);
 330 static bool name_match (char *, char *);
 331
 332 static bool
 333 valid_filename_p (char *fn)
 334 {
 335 #ifdef MSDOS
 336   return *fn == '/' || fn[1] == ':';
 337 #else
 338   return *fn == '/';
 339 #endif
 340 }
 341
 342 /* Find the termcap entry data for terminal type NAME
 343    and store it in the block that BP points to.
 344    Record its address for future use.
 345
 346    If BP is null, space is dynamically allocated.
 347
 348    Return -1 if there is some difficulty accessing the data base
 349    of terminal types,
 350    0 if the data base is accessible but the type NAME is not defined
 351    in it, and some other value otherwise.  */
 352
 353 int
 354 tgetent (char *bp, const char *name)
 355 {
 356   register char *termcap_name;
 357   register int fd;
 358   struct termcap_buffer buf;
 359   register char *bp1;
 360   char *tc_search_point;
 361   char *term;
 362   ptrdiff_t malloc_size = 0;
 363   int c;
 364   char *tcenv = NULL;           /* TERMCAP value, if it contains :tc=.  */
 365   char *indirect = NULL;        /* Terminal type in :tc= in TERMCAP value.  */
 366   bool filep;
 367
 368 #ifdef INTERNAL_TERMINAL
 369   /* For the internal terminal we don't want to read any termcap file,
 370      so fake it.  */
 371   if (!strcmp (name, "internal"))
 372     {
 373       term = INTERNAL_TERMINAL;
 374       if (!bp)
 375         {
 376           malloc_size = 1 + strlen (term);
 377           bp = xmalloc (malloc_size);
 378         }
 379       strcpy (bp, term);
 380       goto ret;
 381     }
 382 #endif /* INTERNAL_TERMINAL */
 383
 384   /* For compatibility with programs like `less' that want to
 385      put data in the termcap buffer themselves as a fallback.  */
 386   if (bp)
 387     term_entry = bp;
 388
 389   termcap_name = getenv ("TERMCAP");
 390   if (termcap_name && *termcap_name == '\0')
 391     termcap_name = NULL;
 392 #if defined (MSDOS) && !defined (TEST)
 393   if (termcap_name && (*termcap_name == '\\'
 394                        || *termcap_name == '/'
 395                        || termcap_name[1] == ':'))
 396     dostounix_filename (termcap_name);
 397 #endif
 398
 399   filep = termcap_name && valid_filename_p (termcap_name);
 400
 401   /* If termcap_name is non-null and starts with / (in the un*x case, that is),
 402      it is a file name to use instead of /etc/termcap.
 403      If it is non-null and does not start with /,
 404      it is the entry itself, but only if
 405      the name the caller requested matches the TERM variable.  */
 406
 407   if (termcap_name && !filep && !strcmp (name, getenv ("TERM")))
 408     {
 409       indirect = tgetst1 (find_capability (termcap_name, "tc"), 0);
 410       if (!indirect)
 411         {
 412           if (!bp)
 413             bp = termcap_name;
 414           else
 415             strcpy (bp, termcap_name);
 416           goto ret;
 417         }
 418       else
 419         {                       /* It has tc=.  Need to read /etc/termcap.  */
 420           tcenv = termcap_name;
 421           termcap_name = NULL;
 422         }
 423     }
 424
 425   if (!termcap_name || !filep)
 426     termcap_name = TERMCAP_FILE;
 427
 428   /* Here we know we must search a file and termcap_name has its name.  */
 429
 430   fd = emacs_open (termcap_name, O_RDONLY | O_TEXT, 0);
 431   if (fd < 0)
 432     return -1;
 433
 434   buf.size = BUFSIZE;
 435   /* Add 1 to size to ensure room for terminating null.  */
 436   buf.beg = xmalloc (buf.size + 1);
 437   term = indirect ? indirect : (char *)name;
 438
 439   if (!bp)
 440     {
 441       malloc_size = indirect ? strlen (tcenv) + 1 : buf.size;
 442       bp = xmalloc (malloc_size);
 443     }
 444   tc_search_point = bp1 = bp;
 445
 446   if (indirect)
 447     /* Copy the data from the environment variable.  */
 448     {
 449       strcpy (bp, tcenv);
 450       bp1 += strlen (tcenv);
 451     }
 452
 453   while (term)
 454     {
 455       /* Scan the file, reading it via buf, till find start of main entry.  */
 456       if (scan_file (term, fd, &buf) == 0)
 457         {
 458           emacs_close (fd);
 459           xfree (buf.beg);
 460           if (malloc_size)
 461             xfree (bp);
 462           return 0;
 463         }
 464
 465       /* Free old `term' if appropriate.  */
 466       if (term != name)
 467         xfree (term);
 468
 469       /* If BP is malloc'd by us, make sure it is big enough.  */
 470       if (malloc_size)
 471         {
 472           ptrdiff_t offset1 = bp1 - bp, offset2 = tc_search_point - bp;
 473           malloc_size = offset1 + buf.size;
 474           bp = termcap_name = xrealloc (bp, malloc_size);
 475           bp1 = termcap_name + offset1;
 476           tc_search_point = termcap_name + offset2;
 477         }
 478
 479       /* Copy the line of the entry from buf into bp.  */
 480       termcap_name = buf.ptr;
 481       while ((*bp1++ = c = *termcap_name++) && c != '\n')
 482         /* Drop out any \ newline sequence.  */
 483         if (c == '\\' && *termcap_name == '\n')
 484           {
 485             bp1--;
 486             termcap_name++;
 487           }
 488       *bp1 = '\0';
 489
 490       /* Does this entry refer to another terminal type's entry?
 491          If something is found, copy it into heap and null-terminate it.  */
 492       tc_search_point = find_capability (tc_search_point, "tc");
 493       term = tgetst1 (tc_search_point, 0);
 494     }
 495
 496   emacs_close (fd);
 497   xfree (buf.beg);
 498
 499   if (malloc_size)
 500     bp = xrealloc (bp, bp1 - bp + 1);
 501
 502  ret:
 503   term_entry = bp;
 504   return 1;
 505 }
 506
 507 /* Given file open on FD and buffer BUFP,
 508    scan the file from the beginning until a line is found
 509    that starts the entry for terminal type STR.
 510    Return 1 if successful, with that line in BUFP,
 511    or 0 if no entry is found in the file.  */
 512
 513 static bool
 514 scan_file (char *str, int fd, struct termcap_buffer *bufp)
 515 {
 516   char *end;
 517
 518   bufp->ptr = bufp->beg;
 519   bufp->full = 0;
 520   bufp->ateof = 0;
 521   *bufp->ptr = '\0';
 522
 523   lseek (fd, 0, 0);
 524
 525   while (!bufp->ateof)
 526     {
 527       /* Read a line into the buffer.  */
 528       end = NULL;
 529       do
 530         {
 531           /* if it is continued, append another line to it,
 532              until a non-continued line ends.  */
 533           end = gobble_line (fd, bufp, end);
 534         }
 535       while (!bufp->ateof && end[-2] == '\\');
 536
 537       if (*bufp->ptr != '#'
 538           && name_match (bufp->ptr, str))
 539         return 1;
 540
 541       /* Discard the line just processed.  */
 542       bufp->ptr = end;
 543     }
 544   return 0;
 545 }
 546
 547 /* Return true if NAME is one of the names specified
 548    by termcap entry LINE.  */
 549
 550 static bool
 551 name_match (char *line, char *name)
 552 {
 553   char *tem;
 554
 555   if (!compare_contin (line, name))
 556     return 1;
 557   /* This line starts an entry.  Is it the right one?  */
 558   for (tem = line; *tem && *tem != '\n' && *tem != ':'; tem++)
 559     if (*tem == '|' && !compare_contin (tem + 1, name))
 560       return 1;
 561
 562   return 0;
 563 }
 564
 565 static bool
 566 compare_contin (char *str1, char *str2)
 567 {
 568   while (1)
 569     {
 570       int c1 = *str1++;
 571       int c2 = *str2++;
 572       while (c1 == '\\' && *str1 == '\n')
 573         {
 574           str1++;
 575           while ((c1 = *str1++) == ' ' || c1 == '\t')
 576             continue;
 577         }
 578       if (c2 == '\0')
 579         {
 580           /* End of type being looked up.  */
 581           if (c1 == '|' || c1 == ':')
 582             /* If end of name in data base, we win.  */
 583             return 0;
 584           else
 585             return 1;
 586         }
 587       else if (c1 != c2)
 588         return 1;
 589     }
 590 }
 591
 592 /* Make sure that the buffer <- BUFP contains a full line
 593    of the file open on FD, starting at the place BUFP->ptr
 594    points to.  Can read more of the file, discard stuff before
 595    BUFP->ptr, or make the buffer bigger.
 596
 597    Return the pointer to after the newline ending the line,
 598    or to the end of the file, if there is no newline to end it.
 599
 600    Can also merge on continuation lines.  If APPEND_END is
 601    non-null, it points past the newline of a line that is
 602    continued; we add another line onto it and regard the whole
 603    thing as one line.  The caller decides when a line is continued.  */
 604
 605 static char *
 606 gobble_line (int fd, register struct termcap_buffer *bufp, char *append_end)
 607 {
 608   register char *end;
 609   register int nread;
 610   register char *buf = bufp->beg;
 611
 612   if (!append_end)
 613     append_end = bufp->ptr;
 614
 615   while (1)
 616     {
 617       end = append_end;
 618       while (*end && *end != '\n') end++;
 619       if (*end)
 620         break;
 621       if (bufp->ateof)
 622         return buf + bufp->full;
 623       if (bufp->ptr == buf)
 624         {
 625           if (bufp->full == bufp->size)
 626             {
 627               ptrdiff_t ptr_offset = bufp->ptr - buf;
 628               ptrdiff_t append_end_offset = append_end - buf;
 629               /* Add 1 to size to ensure room for terminating null.  */
 630               ptrdiff_t size = bufp->size + 1;
 631               bufp->beg = buf = xpalloc (buf, &size, 1, -1, 1);
 632               bufp->size = size - 1;
 633               bufp->ptr = buf + ptr_offset;
 634               append_end = buf + append_end_offset;
 635             }
 636         }
 637       else
 638         {
 639           append_end -= bufp->ptr - buf;
 640           memcpy (buf, bufp->ptr, bufp->full -= bufp->ptr - buf);
 641           bufp->ptr = buf;
 642         }
 643       if (!(nread = read (fd, buf + bufp->full, bufp->size - bufp->full)))
 644         bufp->ateof = 1;
 645       bufp->full += nread;
 646       buf[bufp->full] = '\0';
 647     }
 648   return end + 1;
 649 }