1 /*
2 * Copyright (C) 1984-2025 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
11 /*
12 * Entry point, initialization, miscellaneous routines.
13 */
14
15 #include "less.h"
16 #if MSDOS_COMPILER==WIN32C
17 #define WIN32_LEAN_AND_MEAN
18 #include <windows.h>
19
20 #if defined(MINGW) || defined(_MSC_VER)
21 #include <locale.h>
22 #include <shellapi.h>
23 #endif
24
25 public unsigned less_acp = CP_ACP;
26 #endif
27
28 #include "option.h"
29
30 public char * every_first_cmd = NULL;
31 public lbool new_file;
32 public int is_tty;
33 public IFILE curr_ifile = NULL_IFILE;
34 public IFILE old_ifile = NULL_IFILE;
35 public struct scrpos initial_scrpos;
36 public POSITION start_attnpos = NULL_POSITION;
37 public POSITION end_attnpos = NULL_POSITION;
38 public int wscroll;
39 public constant char *progname;
40 public lbool quitting = FALSE;
41 public int dohelp;
42 public char * init_header = NULL;
43 static int secure_allow_features;
44
45 #if LOGFILE
46 public int logfile = -1;
47 public lbool force_logfile = FALSE;
48 public char * namelogfile = NULL;
49 #endif
50
51 #if EDITOR
52 public constant char * editor;
53 public constant char * editproto;
54 #endif
55
56 #if TAGS
57 extern char * tags;
58 extern char * tagoption;
59 extern int jump_sline;
60 #endif
61
62 #if HAVE_TIME
63 public time_type less_start_time;
64 #endif
65
66 #ifdef WIN32
67 static wchar_t consoleTitle[256];
68 #endif
69
70 public int one_screen;
71 extern int less_is_more;
72 extern lbool missing_cap;
73 extern int know_dumb;
74 extern int quit_if_one_screen;
75 extern int no_init;
76 extern int errmsgs;
77 extern int redraw_on_quit;
78 extern int term_init_done;
79 extern lbool first_time;
80
81 #if MSDOS_COMPILER==WIN32C && (defined(MINGW) || defined(_MSC_VER))
82 /* malloc'ed 0-terminated utf8 of 0-terminated wide ws, or null on errors */
utf8_from_wide(constant wchar_t * ws)83 static char *utf8_from_wide(constant wchar_t *ws)
84 {
85 char *u8 = NULL;
86 int n = WideCharToMultiByte(CP_UTF8, 0, ws, -1, NULL, 0, NULL, NULL);
87 if (n > 0)
88 {
89 u8 = ecalloc(n, sizeof(char));
90 WideCharToMultiByte(CP_UTF8, 0, ws, -1, u8, n, NULL, NULL);
91 }
92 return u8;
93 }
94
95 /*
96 * similar to using UTF8 manifest to make the ANSI APIs UTF8, but dynamically
97 * with setlocale. unlike the manifest, argv and environ are already ACP, so
98 * make them UTF8. Additionally, this affects only the libc/crt API, and so
99 * e.g. fopen filename becomes UTF-8, but CreateFileA filename remains CP_ACP.
100 * CP_ACP remains the original codepage - use the dynamic less_acp instead.
101 * effective on win 10 1803 or later when compiled with ucrt, else no-op.
102 */
try_utf8_locale(int * pargc,constant char *** pargv)103 static void try_utf8_locale(int *pargc, constant char ***pargv)
104 {
105 char *locale_orig = strdup(setlocale(LC_ALL, NULL));
106 wchar_t **wargv = NULL, *wenv, *wp;
107 constant char **u8argv;
108 char *u8e;
109 int i, n;
110
111 if (!setlocale(LC_ALL, ".UTF8"))
112 goto cleanup; /* not win10 1803+ or not ucrt */
113
114 /*
115 * wargv is before glob expansion. some ucrt builds may expand globs
116 * before main is entered, so n may be smaller than the original argc.
117 * that's ok, because later code at main expands globs anyway.
118 */
119 wargv = CommandLineToArgvW(GetCommandLineW(), &n);
120 if (!wargv)
121 goto bad_args;
122
123 u8argv = (constant char **) ecalloc(n + 1, sizeof(char *));
124 for (i = 0; i < n; ++i)
125 {
126 if (!(u8argv[i] = utf8_from_wide(wargv[i])))
127 goto bad_args;
128 }
129 u8argv[n] = 0;
130
131 less_acp = CP_UTF8;
132 *pargc = n;
133 *pargv = u8argv; /* leaked on exit */
134
135 /* convert wide env to utf8 where we can, but don't abort on errors */
136 if ((wenv = GetEnvironmentStringsW()))
137 {
138 for (wp = wenv; *wp; wp += wcslen(wp) + 1)
139 {
140 if ((u8e = utf8_from_wide(wp)))
141 _putenv(u8e);
142 free(u8e); /* windows putenv makes a copy */
143 }
144 FreeEnvironmentStringsW(wenv);
145 }
146
147 goto cleanup;
148
149 bad_args:
150 error("WARNING: cannot use unicode arguments", NULL_PARG);
151 setlocale(LC_ALL, locale_orig);
152
153 cleanup:
154 free(locale_orig);
155 LocalFree(wargv);
156 }
157 #endif
158
159 #if !SECURE
security_feature_error(constant char * type,size_t len,constant char * name)160 static int security_feature_error(constant char *type, size_t len, constant char *name)
161 {
162 PARG parg;
163 size_t msglen = len + strlen(type) + 64;
164 char *msg = ecalloc(msglen, sizeof(char));
165 SNPRINTF3(msg, msglen, "LESSSECURE_ALLOW: %s feature name \"%.*s\"", type, (int) len, name);
166 parg.p_string = msg;
167 error("%s", &parg);
168 free(msg);
169 return 0;
170 }
171
172 /*
173 * Return the SF_xxx value of a secure feature given the name of the feature.
174 */
security_feature(constant char * name,size_t len)175 static int security_feature(constant char *name, size_t len)
176 {
177 struct secure_feature { constant char *name; int sf_value; };
178 static struct secure_feature features[] = {
179 { "edit", SF_EDIT },
180 { "examine", SF_EXAMINE },
181 { "glob", SF_GLOB },
182 { "history", SF_HISTORY },
183 { "lesskey", SF_LESSKEY },
184 { "lessopen", SF_LESSOPEN },
185 { "logfile", SF_LOGFILE },
186 { "osc8", SF_OSC8_OPEN },
187 { "pipe", SF_PIPE },
188 { "shell", SF_SHELL },
189 { "stop", SF_STOP },
190 { "tags", SF_TAGS },
191 };
192 int i;
193 int match = -1;
194
195 for (i = 0; i < countof(features); i++)
196 {
197 if (strncmp(features[i].name, name, len) == 0)
198 {
199 if (match >= 0) /* name is ambiguous */
200 return security_feature_error("ambiguous", len, name);
201 match = i;
202 }
203 }
204 if (match < 0)
205 return security_feature_error("invalid", len, name);
206 return features[match].sf_value;
207 }
208 #endif /* !SECURE */
209
210 /*
211 * Set the secure_allow_features bitmask, which controls
212 * whether certain secure features are allowed.
213 */
init_secure(void)214 static void init_secure(void)
215 {
216 #if SECURE
217 secure_allow_features = 0;
218 #else
219 constant char *str = lgetenv("LESSSECURE");
220 if (isnullenv(str))
221 secure_allow_features = ~0; /* allow everything */
222 else
223 secure_allow_features = 0; /* allow nothing */
224
225 str = lgetenv("LESSSECURE_ALLOW");
226 if (!isnullenv(str))
227 {
228 for (;;)
229 {
230 constant char *estr;
231 while (*str == ' ' || *str == ',') ++str; /* skip leading spaces/commas */
232 if (*str == '\0') break;
233 estr = strchr(str, ',');
234 if (estr == NULL) estr = str + strlen(str);
235 while (estr > str && estr[-1] == ' ') --estr; /* trim trailing spaces */
236 secure_allow_features |= security_feature(str, ptr_diff(estr, str));
237 str = estr;
238 }
239 }
240 #endif
241 }
242
243 /*
244 * Entry point.
245 */
main(int argc,constant char * argv[])246 int main(int argc, constant char *argv[])
247 {
248 IFILE ifile;
249 constant char *s;
250
251 #if MSDOS_COMPILER==WIN32C && (defined(MINGW) || defined(_MSC_VER))
252 if (GetACP() != CP_UTF8) /* not using a UTF-8 manifest */
253 try_utf8_locale(&argc, &argv);
254 #endif
255
256 #ifdef __EMX__
257 _response(&argc, &argv);
258 _wildcard(&argc, &argv);
259 #endif
260
261 progname = *argv++;
262 argc--;
263 init_secure();
264
265 #ifdef WIN32
266 if (getenv("HOME") == NULL)
267 {
268 /*
269 * If there is no HOME environment variable,
270 * try the concatenation of HOMEDRIVE + HOMEPATH.
271 */
272 char *drive = getenv("HOMEDRIVE");
273 char *path = getenv("HOMEPATH");
274 if (drive != NULL && path != NULL)
275 {
276 char *env = (char *) ecalloc(strlen(drive) +
277 strlen(path) + 6, sizeof(char));
278 strcpy(env, "HOME=");
279 strcat(env, drive);
280 strcat(env, path);
281 putenv(env);
282 }
283 }
284 /* on failure, consoleTitle is already a valid empty string */
285 GetConsoleTitleW(consoleTitle, countof(consoleTitle));
286 #endif /* WIN32 */
287
288 /*
289 * Process command line arguments and LESS environment arguments.
290 * Command line arguments override environment arguments.
291 */
292 is_tty = isatty(1);
293 init_mark();
294 init_cmds();
295 init_poll();
296 init_charset();
297 init_line();
298 init_cmdhist();
299 init_option();
300 init_search();
301
302 /*
303 * If the name of the executable program is "more",
304 * act like LESS_IS_MORE is set.
305 */
306 if (strcmp(last_component(progname), "more") == 0 &&
307 isnullenv(lgetenv("LESS_IS_MORE"))) {
308 less_is_more = 1;
309 scan_option("-fG", FALSE);
310 }
311
312 init_prompt();
313
314 init_unsupport();
315 s = lgetenv(less_is_more ? "MORE" : "LESS");
316 if (s != NULL)
317 scan_option(s, TRUE);
318
319 #define isoptstring(s) less_is_more ? (((s)[0] == '-') && (s)[1] != '\0') : \
320 (((s)[0] == '-' || (s)[0] == '+') && (s)[1] != '\0')
321 while (argc > 0 && (isoptstring(*argv) || isoptpending()))
322 {
323 s = *argv++;
324 argc--;
325 if (strcmp(s, "--") == 0)
326 break;
327 scan_option(s, FALSE);
328 }
329 #undef isoptstring
330
331 if (isoptpending())
332 {
333 /*
334 * Last command line option was a flag requiring a
335 * following string, but there was no following string.
336 */
337 nopendopt();
338 quit(QUIT_OK);
339 }
340
341 if (less_is_more)
342 no_init = TRUE;
343
344 get_term();
345 expand_cmd_tables();
346
347 #if EDITOR
348 editor = lgetenv("VISUAL");
349 if (isnullenv(editor))
350 {
351 editor = lgetenv("EDITOR");
352 if (isnullenv(editor))
353 editor = EDIT_PGM;
354 }
355 editproto = lgetenv("LESSEDIT");
356 if (isnullenv(editproto))
357 editproto = "%E ?lm+%lm. %g";
358 #endif
359
360 /*
361 * Call get_ifile with all the command line filenames
362 * to "register" them with the ifile system.
363 */
364 ifile = NULL_IFILE;
365 if (dohelp)
366 ifile = get_ifile(FAKE_HELPFILE, ifile);
367 while (argc-- > 0)
368 {
369 #if (MSDOS_COMPILER && MSDOS_COMPILER != DJGPPC)
370 /*
371 * Because the "shell" doesn't expand filename patterns,
372 * treat each argument as a filename pattern rather than
373 * a single filename.
374 * Expand the pattern and iterate over the expanded list.
375 */
376 struct textlist tlist;
377 constant char *filename;
378 char *gfilename;
379 char *qfilename;
380
381 gfilename = lglob(*argv++);
382 init_textlist(&tlist, gfilename);
383 filename = NULL;
384 while ((filename = forw_textlist(&tlist, filename)) != NULL)
385 {
386 qfilename = shell_unquote(filename);
387 (void) get_ifile(qfilename, ifile);
388 free(qfilename);
389 ifile = prev_ifile(NULL_IFILE);
390 }
391 free(gfilename);
392 #else
393 (void) get_ifile(*argv++, ifile);
394 ifile = prev_ifile(NULL_IFILE);
395 #endif
396 }
397 /*
398 * Set up terminal, etc.
399 */
400 if (!is_tty)
401 {
402 /*
403 * Output is not a tty.
404 * Just copy the input file(s) to output.
405 */
406 set_output(1); /* write to stdout */
407 SET_BINARY(1);
408 if (edit_first() == 0)
409 {
410 do {
411 cat_file();
412 } while (edit_next(1) == 0);
413 }
414 quit(QUIT_OK);
415 }
416
417 if (missing_cap && !know_dumb && !less_is_more)
418 error("WARNING: terminal is not fully functional", NULL_PARG);
419 open_getchr();
420 raw_mode(1);
421 init_signals(1);
422 #if HAVE_TIME
423 less_start_time = get_time();
424 #endif
425
426 /*
427 * Select the first file to examine.
428 */
429 #if TAGS
430 if (tagoption != NULL || strcmp(tags, "-") == 0)
431 {
432 /*
433 * A -t option was given.
434 * Verify that no filenames were also given.
435 * Edit the file selected by the "tags" search,
436 * and search for the proper line in the file.
437 */
438 if (nifile() > 0)
439 {
440 error("No filenames allowed with -t option", NULL_PARG);
441 quit(QUIT_ERROR);
442 }
443 findtag(tagoption);
444 if (edit_tagfile()) /* Edit file which contains the tag */
445 quit(QUIT_ERROR);
446 /*
447 * Search for the line which contains the tag.
448 * Set up initial_scrpos so we display that line.
449 */
450 initial_scrpos.pos = tagsearch();
451 if (initial_scrpos.pos == NULL_POSITION)
452 quit(QUIT_ERROR);
453 initial_scrpos.ln = jump_sline;
454 } else
455 #endif
456 {
457 if (edit_first())
458 quit(QUIT_ERROR);
459 /*
460 * See if file fits on one screen to decide whether
461 * to send terminal init. But don't need this
462 * if -X (no_init) overrides this (see init()).
463 */
464 if (quit_if_one_screen)
465 {
466 if (nifile() > 1) /* If more than one file, -F cannot be used */
467 quit_if_one_screen = FALSE;
468 else if (!no_init)
469 one_screen = get_one_screen();
470 }
471 }
472 if (init_header != NULL)
473 {
474 opt_header(TOGGLE, init_header);
475 free(init_header);
476 init_header = NULL;
477 }
478
479 if (errmsgs > 0)
480 {
481 /*
482 * We displayed some messages on error output
483 * (file descriptor 2; see flush()).
484 * Before erasing the screen contents, wait for a keystroke.
485 */
486 less_printf("Press RETURN to continue ", NULL_PARG);
487 get_return();
488 putchr('\n');
489 }
490 set_output(1);
491 init();
492 commands();
493 quit(QUIT_OK);
494 /*NOTREACHED*/
495 return (0);
496 }
497
498 /*
499 * Copy a string to a "safe" place
500 * (that is, to a buffer allocated by calloc).
501 */
saven(constant char * s,size_t n)502 public char * saven(constant char *s, size_t n)
503 {
504 char *p = (char *) ecalloc(n+1, sizeof(char));
505 strncpy(p, s, n);
506 p[n] = '\0';
507 return (p);
508 }
509
save(constant char * s)510 public char * save(constant char *s)
511 {
512 return saven(s, strlen(s));
513 }
514
out_of_memory(void)515 public void out_of_memory(void)
516 {
517 error("Cannot allocate memory", NULL_PARG);
518 quit(QUIT_ERROR);
519 }
520
521 /*
522 * Allocate memory.
523 * Like calloc(), but never returns an error (NULL).
524 */
ecalloc(size_t count,size_t size)525 public void * ecalloc(size_t count, size_t size)
526 {
527 void * p;
528
529 p = (void *) calloc(count, size);
530 if (p == NULL)
531 out_of_memory();
532 return p;
533 }
534
535 /*
536 * Skip leading spaces in a string.
537 */
skipsp(char * s)538 public char * skipsp(char *s)
539 {
540 while (*s == ' ' || *s == '\t')
541 s++;
542 return (s);
543 }
544
545 /* {{ There must be a better way. }} */
skipspc(constant char * s)546 public constant char * skipspc(constant char *s)
547 {
548 while (*s == ' ' || *s == '\t')
549 s++;
550 return (s);
551 }
552
553 /*
554 * See how many characters of two strings are identical.
555 * If uppercase is true, the first string must begin with an uppercase
556 * character; the remainder of the first string may be either case.
557 */
sprefix(constant char * ps,constant char * s,int uppercase)558 public size_t sprefix(constant char *ps, constant char *s, int uppercase)
559 {
560 char c;
561 char sc;
562 size_t len = 0;
563
564 for ( ; *s != '\0'; s++, ps++)
565 {
566 c = *ps;
567 if (uppercase)
568 {
569 if (len == 0 && ASCII_IS_LOWER(c))
570 return (0);
571 if (ASCII_IS_UPPER(c))
572 c = ASCII_TO_LOWER(c);
573 }
574 sc = *s;
575 if (len > 0 && ASCII_IS_UPPER(sc))
576 sc = ASCII_TO_LOWER(sc);
577 if (c != sc)
578 break;
579 len++;
580 }
581 return (len);
582 }
583
584 /*
585 * Exit the program.
586 */
quit(int status)587 public void quit(int status)
588 {
589 static int save_status;
590
591 /*
592 * Put cursor at bottom left corner, clear the line,
593 * reset the terminal modes, and exit.
594 */
595 if (status < 0)
596 status = save_status;
597 else
598 save_status = status;
599 quitting = TRUE;
600 check_altpipe_error();
601 if (interactive())
602 clear_bot();
603 deinit();
604 flush();
605 if (redraw_on_quit && term_init_done)
606 {
607 /*
608 * The last file text displayed might have been on an
609 * alternate screen, which now (since deinit) cannot be seen.
610 * redraw_on_quit tells us to redraw it on the main screen.
611 */
612 first_time = TRUE; /* Don't print "skipping" or tildes */
613 repaint();
614 flush();
615 }
616 edit((char*)NULL);
617 save_cmdhist();
618 raw_mode(0);
619 #if MSDOS_COMPILER && MSDOS_COMPILER != DJGPPC
620 /*
621 * If we don't close 2, we get some garbage from
622 * 2's buffer when it flushes automatically.
623 * I cannot track this one down RB
624 * The same bug shows up if we use ^C^C to abort.
625 */
626 close(2);
627 #endif
628 #ifdef WIN32
629 SetConsoleTitleW(consoleTitle);
630 #endif
631 close_getchr();
632 exit(status);
633 }
634
635 /*
636 * Are all the features in the features mask allowed by security?
637 */
secure_allow(int features)638 public int secure_allow(int features)
639 {
640 return ((secure_allow_features & features) == features);
641 }
642