contrib/less/lesskey_parse.c

   1 /*
   2  * Copyright (C) 1984-2022  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, see the README file.
   8  */
   9
  10 #include <stdio.h>
  11 #include <string.h>
  12 #include <stdlib.h>
  13 #include "lesskey.h"
  14 #include "cmd.h"
  15 #include "xbuf.h"
  16 #include "defines.h"
  17
  18 #define CONTROL(c)      ((c)&037)
  19 #define ESC             CONTROL('[')
  20
  21 extern void lesskey_parse_error(char *msg);
  22 extern char *homefile(char *filename);
  23 extern void *ecalloc(int count, unsigned int size);
  24 extern int lstrtoi(char *str, char **end);
  25 extern char version[];
  26
  27 static int linenum;
  28 static int errors;
  29 static int less_version = 0;
  30 static char *lesskey_file;
  31
  32 static struct lesskey_cmdname cmdnames[] =
  33 {
  34         { "back-bracket",         A_B_BRACKET },
  35         { "back-line",            A_B_LINE },
  36         { "back-line-force",      A_BF_LINE },
  37         { "back-screen",          A_B_SCREEN },
  38         { "back-scroll",          A_B_SCROLL },
  39         { "back-search",          A_B_SEARCH },
  40         { "back-window",          A_B_WINDOW },
  41         { "clear-mark",           A_CLRMARK },
  42         { "debug",                A_DEBUG },
  43         { "digit",                A_DIGIT },
  44         { "display-flag",         A_DISP_OPTION },
  45         { "display-option",       A_DISP_OPTION },
  46         { "end",                  A_GOEND },
  47         { "end-scroll",           A_RRSHIFT },
  48         { "examine",              A_EXAMINE },
  49         { "filter",               A_FILTER },
  50         { "first-cmd",            A_FIRSTCMD },
  51         { "firstcmd",             A_FIRSTCMD },
  52         { "flush-repaint",        A_FREPAINT },
  53         { "forw-bracket",         A_F_BRACKET },
  54         { "forw-forever",         A_F_FOREVER },
  55         { "forw-until-hilite",    A_F_UNTIL_HILITE },
  56         { "forw-line",            A_F_LINE },
  57         { "forw-line-force",      A_FF_LINE },
  58         { "forw-screen",          A_F_SCREEN },
  59         { "forw-screen-force",    A_FF_SCREEN },
  60         { "forw-scroll",          A_F_SCROLL },
  61         { "forw-search",          A_F_SEARCH },
  62         { "forw-window",          A_F_WINDOW },
  63         { "goto-end",             A_GOEND },
  64         { "goto-end-buffered",    A_GOEND_BUF },
  65         { "goto-line",            A_GOLINE },
  66         { "goto-mark",            A_GOMARK },
  67         { "help",                 A_HELP },
  68         { "index-file",           A_INDEX_FILE },
  69         { "invalid",              A_UINVALID },
  70         { "left-scroll",          A_LSHIFT },
  71         { "next-file",            A_NEXT_FILE },
  72         { "next-tag",             A_NEXT_TAG },
  73         { "noaction",             A_NOACTION },
  74         { "no-scroll",            A_LLSHIFT },
  75         { "percent",              A_PERCENT },
  76         { "pipe",                 A_PIPE },
  77         { "prev-file",            A_PREV_FILE },
  78         { "prev-tag",             A_PREV_TAG },
  79         { "quit",                 A_QUIT },
  80         { "remove-file",          A_REMOVE_FILE },
  81         { "repaint",              A_REPAINT },
  82         { "repaint-flush",        A_FREPAINT },
  83         { "repeat-search",        A_AGAIN_SEARCH },
  84         { "repeat-search-all",    A_T_AGAIN_SEARCH },
  85         { "reverse-search",       A_REVERSE_SEARCH },
  86         { "reverse-search-all",   A_T_REVERSE_SEARCH },
  87         { "right-scroll",         A_RSHIFT },
  88         { "set-mark",             A_SETMARK },
  89         { "set-mark-bottom",      A_SETMARKBOT },
  90         { "shell",                A_SHELL },
  91         { "status",               A_STAT },
  92         { "toggle-flag",          A_OPT_TOGGLE },
  93         { "toggle-option",        A_OPT_TOGGLE },
  94         { "undo-hilite",          A_UNDO_SEARCH },
  95         { "clear-search",         A_CLR_SEARCH },
  96         { "version",              A_VERSION },
  97         { "visual",               A_VISUAL },
  98         { NULL,   0 }
  99 };
 100
 101 static struct lesskey_cmdname editnames[] =
 102 {
 103         { "back-complete",      EC_B_COMPLETE },
 104         { "backspace",          EC_BACKSPACE },
 105         { "delete",             EC_DELETE },
 106         { "down",               EC_DOWN },
 107         { "end",                EC_END },
 108         { "expand",             EC_EXPAND },
 109         { "forw-complete",      EC_F_COMPLETE },
 110         { "home",               EC_HOME },
 111         { "insert",             EC_INSERT },
 112         { "invalid",            EC_UINVALID },
 113         { "kill-line",          EC_LINEKILL },
 114         { "abort",              EC_ABORT },
 115         { "left",               EC_LEFT },
 116         { "literal",            EC_LITERAL },
 117         { "right",              EC_RIGHT },
 118         { "up",                 EC_UP },
 119         { "word-backspace",     EC_W_BACKSPACE },
 120         { "word-delete",        EC_W_DELETE },
 121         { "word-left",          EC_W_LEFT },
 122         { "word-right",         EC_W_RIGHT },
 123         { NULL, 0 }
 124 };
 125
 126 /*
 127  * Print a parse error message.
 128  */
 129         static void
 130 parse_error(fmt, arg1)
 131         char *fmt;
 132         char *arg1;
 133 {
 134         char buf[1024];
 135         int n = snprintf(buf, sizeof(buf), "%s: line %d: ", lesskey_file, linenum);
 136         if (n >= 0 && n < sizeof(buf))
 137                 snprintf(buf+n, sizeof(buf)-n, fmt, arg1);
 138         ++errors;
 139         lesskey_parse_error(buf);
 140 }
 141
 142 /*
 143  * Initialize lesskey_tables.
 144  */
 145         static void
 146 init_tables(tables)
 147         struct lesskey_tables *tables;
 148 {
 149         tables->currtable = &tables->cmdtable;
 150
 151         tables->cmdtable.names = cmdnames;
 152         tables->cmdtable.is_var = 0;
 153         xbuf_init(&tables->cmdtable.buf);
 154
 155         tables->edittable.names = editnames;
 156         tables->edittable.is_var = 0;
 157         xbuf_init(&tables->edittable.buf);
 158
 159         tables->vartable.names = NULL;
 160         tables->vartable.is_var = 1;
 161         xbuf_init(&tables->vartable.buf);
 162 }
 163
 164 #define CHAR_STRING_LEN 8
 165
 166         static char *
 167 char_string(buf, ch, lit)
 168         char *buf;
 169         int ch;
 170         int lit;
 171 {
 172         if (lit || (ch >= 0x20 && ch < 0x7f))
 173         {
 174                 buf[0] = ch;
 175                 buf[1] = '\0';
 176         } else
 177         {
 178                 snprintf(buf, CHAR_STRING_LEN, "\\x%02x", ch);
 179         }
 180         return buf;
 181 }
 182
 183 /*
 184  * Increment char pointer by one up to terminating nul byte.
 185  */
 186         static char *
 187 increment_pointer(p)
 188         char *p;
 189 {
 190         if (*p == '\0')
 191                 return p;
 192         return p+1;
 193 }
 194
 195 /*
 196  * Parse one character of a string.
 197  */
 198         static char *
 199 tstr(pp, xlate)
 200         char **pp;
 201         int xlate;
 202 {
 203         char *p;
 204         char ch;
 205         int i;
 206         static char buf[CHAR_STRING_LEN];
 207         static char tstr_control_k[] =
 208                 { SK_SPECIAL_KEY, SK_CONTROL_K, 6, 1, 1, 1, '\0' };
 209
 210         p = *pp;
 211         switch (*p)
 212         {
 213         case '\\':
 214                 ++p;
 215                 switch (*p)
 216                 {
 217                 case '0': case '1': case '2': case '3':
 218                 case '4': case '5': case '6': case '7':
 219                         /*
 220                          * Parse an octal number.
 221                          */
 222                         ch = 0;
 223                         i = 0;
 224                         do
 225                                 ch = 8*ch + (*p - '0');
 226                         while (*++p >= '0' && *p <= '7' && ++i < 3);
 227                         *pp = p;
 228                         if (xlate && ch == CONTROL('K'))
 229                                 return tstr_control_k;
 230                         return char_string(buf, ch, 1);
 231                 case 'b':
 232                         *pp = p+1;
 233                         return ("\b");
 234                 case 'e':
 235                         *pp = p+1;
 236                         return char_string(buf, ESC, 1);
 237                 case 'n':
 238                         *pp = p+1;
 239                         return ("\n");
 240                 case 'r':
 241                         *pp = p+1;
 242                         return ("\r");
 243                 case 't':
 244                         *pp = p+1;
 245                         return ("\t");
 246                 case 'k':
 247                         if (xlate)
 248                         {
 249                                 switch (*++p)
 250                                 {
 251                                 case 'b': ch = SK_BACKSPACE; break;
 252                                 case 'B': ch = SK_CTL_BACKSPACE; break;
 253                                 case 'd': ch = SK_DOWN_ARROW; break;
 254                                 case 'D': ch = SK_PAGE_DOWN; break;
 255                                 case 'e': ch = SK_END; break;
 256                                 case 'h': ch = SK_HOME; break;
 257                                 case 'i': ch = SK_INSERT; break;
 258                                 case 'l': ch = SK_LEFT_ARROW; break;
 259                                 case 'L': ch = SK_CTL_LEFT_ARROW; break;
 260                                 case 'r': ch = SK_RIGHT_ARROW; break;
 261                                 case 'R': ch = SK_CTL_RIGHT_ARROW; break;
 262                                 case 't': ch = SK_BACKTAB; break;
 263                                 case 'u': ch = SK_UP_ARROW; break;
 264                                 case 'U': ch = SK_PAGE_UP; break;
 265                                 case 'x': ch = SK_DELETE; break;
 266                                 case 'X': ch = SK_CTL_DELETE; break;
 267                                 case '1': ch = SK_F1; break;
 268                                 default:
 269                                         parse_error("invalid escape sequence \"\\k%s\"", char_string(buf, *p, 0));
 270                                         *pp = increment_pointer(p);
 271                                         return ("");
 272                                 }
 273                                 *pp = p+1;
 274                                 buf[0] = SK_SPECIAL_KEY;
 275                                 buf[1] = ch;
 276                                 buf[2] = 6;
 277                                 buf[3] = 1;
 278                                 buf[4] = 1;
 279                                 buf[5] = 1;
 280                                 buf[6] = '\0';
 281                                 return (buf);
 282                         }
 283                         /* FALLTHRU */
 284                 default:
 285                         /*
 286                          * Backslash followed by any other char
 287                          * just means that char.
 288                          */
 289                         *pp = increment_pointer(p);
 290                         char_string(buf, *p, 1);
 291                         if (xlate && buf[0] == CONTROL('K'))
 292                                 return tstr_control_k;
 293                         return (buf);
 294                 }
 295         case '^':
 296                 /*
 297                  * Caret means CONTROL.
 298                  */
 299                 *pp = increment_pointer(p+1);
 300                 char_string(buf, CONTROL(p[1]), 1);
 301                 if (xlate && buf[0] == CONTROL('K'))
 302                         return tstr_control_k;
 303                 return (buf);
 304         }
 305         *pp = increment_pointer(p);
 306         char_string(buf, *p, 1);
 307         if (xlate && buf[0] == CONTROL('K'))
 308                 return tstr_control_k;
 309         return (buf);
 310 }
 311
 312         static int
 313 issp(ch)
 314         char ch;
 315 {
 316         return (ch == ' ' || ch == '\t');
 317 }
 318
 319 /*
 320  * Skip leading spaces in a string.
 321  */
 322         static char *
 323 skipsp(s)
 324         char *s;
 325 {
 326         while (issp(*s))
 327                 s++;
 328         return (s);
 329 }
 330
 331 /*
 332  * Skip non-space characters in a string.
 333  */
 334         static char *
 335 skipnsp(s)
 336         char *s;
 337 {
 338         while (*s != '\0' && !issp(*s))
 339                 s++;
 340         return (s);
 341 }
 342
 343 /*
 344  * Clean up an input line:
 345  * strip off the trailing newline & any trailing # comment.
 346  */
 347         static char *
 348 clean_line(s)
 349         char *s;
 350 {
 351         int i;
 352
 353         s = skipsp(s);
 354         for (i = 0;  s[i] != '\0' && s[i] != '\n' && s[i] != '\r';  i++)
 355                 if (s[i] == '#' && (i == 0 || s[i-1] != '\\'))
 356                         break;
 357         s[i] = '\0';
 358         return (s);
 359 }
 360
 361 /*
 362  * Add a byte to the output command table.
 363  */
 364         static void
 365 add_cmd_char(c, tables)
 366         int c;
 367         struct lesskey_tables *tables;
 368 {
 369         xbuf_add(&tables->currtable->buf, c);
 370 }
 371
 372         static void
 373 erase_cmd_char(tables)
 374         struct lesskey_tables *tables;
 375 {
 376         xbuf_pop(&tables->currtable->buf);
 377 }
 378
 379 /*
 380  * Add a string to the output command table.
 381  */
 382         static void
 383 add_cmd_str(s, tables)
 384         char *s;
 385         struct lesskey_tables *tables;
 386 {
 387         for ( ;  *s != '\0';  s++)
 388                 add_cmd_char(*s, tables);
 389 }
 390
 391 /*
 392  * Does a given version number match the running version?
 393  * Operator compares the running version to the given version.
 394  */
 395         static int
 396 match_version(op, ver)
 397         char op;
 398         int ver;
 399 {
 400         switch (op)
 401         {
 402         case '>': return less_version > ver;
 403         case '<': return less_version < ver;
 404         case '+': return less_version >= ver;
 405         case '-': return less_version <= ver;
 406         case '=': return less_version == ver;
 407         case '!': return less_version != ver;
 408         default: return 0; /* cannot happen */
 409         }
 410 }
 411
 412 /*
 413  * Handle a #version line.
 414  * If the version matches, return the part of the line that should be executed.
 415  * Otherwise, return NULL.
 416  */
 417         static char *
 418 version_line(s, tables)
 419         char *s;
 420         struct lesskey_tables *tables;
 421 {
 422         char op;
 423         int ver;
 424         char *e;
 425         char buf[CHAR_STRING_LEN];
 426
 427         s += strlen("#version");
 428         s = skipsp(s);
 429         op = *s++;
 430         /* Simplify 2-char op to one char. */
 431         switch (op)
 432         {
 433         case '<': if (*s == '=') { s++; op = '-'; } break;
 434         case '>': if (*s == '=') { s++; op = '+'; } break;
 435         case '=': if (*s == '=') { s++; } break;
 436         case '!': if (*s == '=') { s++; } break;
 437         default:
 438                 parse_error("invalid operator '%s' in #version line", char_string(buf, op, 0));
 439                 return (NULL);
 440         }
 441         s = skipsp(s);
 442         ver = lstrtoi(s, &e);
 443         if (e == s)
 444         {
 445                 parse_error("non-numeric version number in #version line", "");
 446                 return (NULL);
 447         }
 448         if (!match_version(op, ver))
 449                 return (NULL);
 450         return (e);
 451 }
 452
 453 /*
 454  * See if we have a special "control" line.
 455  */
 456         static char *
 457 control_line(s, tables)
 458         char *s;
 459         struct lesskey_tables *tables;
 460 {
 461 #define PREFIX(str,pat) (strncmp(str,pat,strlen(pat)) == 0)
 462
 463         if (PREFIX(s, "#line-edit"))
 464         {
 465                 tables->currtable = &tables->edittable;
 466                 return (NULL);
 467         }
 468         if (PREFIX(s, "#command"))
 469         {
 470                 tables->currtable = &tables->cmdtable;
 471                 return (NULL);
 472         }
 473         if (PREFIX(s, "#env"))
 474         {
 475                 tables->currtable = &tables->vartable;
 476                 return (NULL);
 477         }
 478         if (PREFIX(s, "#stop"))
 479         {
 480                 add_cmd_char('\0', tables);
 481                 add_cmd_char(A_END_LIST, tables);
 482                 return (NULL);
 483         }
 484         if (PREFIX(s, "#version"))
 485         {
 486                 return (version_line(s, tables));
 487         }
 488         return (s);
 489 }
 490
 491 /*
 492  * Find an action, given the name of the action.
 493  */
 494         static int
 495 findaction(actname, tables)
 496         char *actname;
 497         struct lesskey_tables *tables;
 498 {
 499         int i;
 500
 501         for (i = 0;  tables->currtable->names[i].cn_name != NULL;  i++)
 502                 if (strcmp(tables->currtable->names[i].cn_name, actname) == 0)
 503                         return (tables->currtable->names[i].cn_action);
 504         parse_error("unknown action: \"%s\"", actname);
 505         return (A_INVALID);
 506 }
 507
 508 /*
 509  * Parse a line describing one key binding, of the form
 510  *  KEY ACTION [EXTRA]
 511  * where KEY is the user key sequence, ACTION is the
 512  * resulting less action, and EXTRA is an "extra" user
 513  * key sequence injected after the action.
 514  */
 515         static void
 516 parse_cmdline(p, tables)
 517         char *p;
 518         struct lesskey_tables *tables;
 519 {
 520         char *actname;
 521         int action;
 522         char *s;
 523         char c;
 524
 525         /*
 526          * Parse the command string and store it in the current table.
 527          */
 528         do
 529         {
 530                 s = tstr(&p, 1);
 531                 add_cmd_str(s, tables);
 532         } while (*p != '\0' && !issp(*p));
 533         /*
 534          * Terminate the command string with a null byte.
 535          */
 536         add_cmd_char('\0', tables);
 537
 538         /*
 539          * Skip white space between the command string
 540          * and the action name.
 541          * Terminate the action name with a null byte.
 542          */
 543         p = skipsp(p);
 544         if (*p == '\0')
 545         {
 546                 parse_error("missing action", "");
 547                 return;
 548         }
 549         actname = p;
 550         p = skipnsp(p);
 551         c = *p;
 552         *p = '\0';
 553
 554         /*
 555          * Parse the action name and store it in the current table.
 556          */
 557         action = findaction(actname, tables);
 558
 559         /*
 560          * See if an extra string follows the action name.
 561          */
 562         *p = c;
 563         p = skipsp(p);
 564         if (*p == '\0')
 565         {
 566                 add_cmd_char(action, tables);
 567         } else
 568         {
 569                 /*
 570                  * OR the special value A_EXTRA into the action byte.
 571                  * Put the extra string after the action byte.
 572                  */
 573                 add_cmd_char(action | A_EXTRA, tables);
 574                 while (*p != '\0')
 575                         add_cmd_str(tstr(&p, 0), tables);
 576                 add_cmd_char('\0', tables);
 577         }
 578 }
 579
 580 /*
 581  * Parse a variable definition line, of the form
 582  *  NAME = VALUE
 583  */
 584         static void
 585 parse_varline(line, tables)
 586         char *line;
 587         struct lesskey_tables *tables;
 588 {
 589         char *s;
 590         char *p = line;
 591         char *eq;
 592
 593         eq = strchr(line, '=');
 594         if (eq != NULL && eq > line && eq[-1] == '+')
 595         {
 596                 /*
 597                  * Rather ugly way of handling a += line.
 598                  * {{ Note that we ignore the variable name and
 599                  *    just append to the previously defined variable. }}
 600                  */
 601                 erase_cmd_char(tables); /* backspace over the final null */
 602                 p = eq+1;
 603         } else
 604         {
 605                 do
 606                 {
 607                         s = tstr(&p, 0);
 608                         add_cmd_str(s, tables);
 609                 } while (*p != '\0' && !issp(*p) && *p != '=');
 610                 /*
 611                  * Terminate the variable name with a null byte.
 612                  */
 613                 add_cmd_char('\0', tables);
 614                 p = skipsp(p);
 615                 if (*p++ != '=')
 616                 {
 617                         parse_error("missing = in variable definition", "");
 618                         return;
 619                 }
 620                 add_cmd_char(EV_OK|A_EXTRA, tables);
 621         }
 622         p = skipsp(p);
 623         while (*p != '\0')
 624         {
 625                 s = tstr(&p, 0);
 626                 add_cmd_str(s, tables);
 627         }
 628         add_cmd_char('\0', tables);
 629 }
 630
 631 /*
 632  * Parse a line from the lesskey file.
 633  */
 634         static void
 635 parse_line(line, tables)
 636         char *line;
 637         struct lesskey_tables *tables;
 638 {
 639         char *p;
 640
 641         /*
 642          * See if it is a control line.
 643          */
 644         p = control_line(line, tables);
 645         if (p == NULL)
 646                 return;
 647         /*
 648          * Skip leading white space.
 649          * Replace the final newline with a null byte.
 650          * Ignore blank lines and comments.
 651          */
 652         p = clean_line(p);
 653         if (*p == '\0')
 654                 return;
 655
 656         if (tables->currtable->is_var)
 657                 parse_varline(p, tables);
 658         else
 659                 parse_cmdline(p, tables);
 660 }
 661
 662 /*
 663  * Parse a lesskey source file and store result in tables.
 664  */
 665         int
 666 parse_lesskey(infile, tables)
 667         char *infile;
 668         struct lesskey_tables *tables;
 669 {
 670         FILE *desc;
 671         char line[1024];
 672
 673         if (infile == NULL)
 674                 infile = homefile(DEF_LESSKEYINFILE);
 675         lesskey_file = infile;
 676
 677         init_tables(tables);
 678         errors = 0;
 679         linenum = 0;
 680         if (less_version == 0)
 681                 less_version = lstrtoi(version, NULL);
 682
 683         /*
 684          * Open the input file.
 685          */
 686         if (strcmp(infile, "-") == 0)
 687                 desc = stdin;
 688         else if ((desc = fopen(infile, "r")) == NULL)
 689         {
 690                 /* parse_error("cannot open lesskey file %s", infile); */
 691                 return (-1);
 692         }
 693
 694         /*
 695          * Read and parse the input file, one line at a time.
 696          */
 697         while (fgets(line, sizeof(line), desc) != NULL)
 698         {
 699                 ++linenum;
 700                 parse_line(line, tables);
 701         }
 702         fclose(desc);
 703         return (errors);
 704 }