xref: /freebsd/contrib/less/main.c (revision 9f27341c336aa12f6c7163c17e646e76c813b689)
1 /* $FreeBSD$ */
2 /*
3  * Copyright (C) 1984-2023  Mark Nudelman
4  *
5  * You may distribute under the terms of either the GNU General Public
6  * License or the Less License, as specified in the README file.
7  *
8  * For more information, see the README file.
9  */
10 
11 
12 /*
13  * Entry point, initialization, miscellaneous routines.
14  */
15 
16 #include "less.h"
17 #if MSDOS_COMPILER==WIN32C
18 #define WIN32_LEAN_AND_MEAN
19 #include <windows.h>
20 #endif
21 
22 public char *   every_first_cmd = NULL;
23 public int      new_file;
24 public int      is_tty;
25 public IFILE    curr_ifile = NULL_IFILE;
26 public IFILE    old_ifile = NULL_IFILE;
27 public struct scrpos initial_scrpos;
28 public POSITION start_attnpos = NULL_POSITION;
29 public POSITION end_attnpos = NULL_POSITION;
30 public int      wscroll;
31 public char *   progname;
32 public int      quitting;
33 public int      secure;
34 public int      dohelp;
35 
36 #if LOGFILE
37 public int      logfile = -1;
38 public int      force_logfile = FALSE;
39 public char *   namelogfile = NULL;
40 #endif
41 
42 #if EDITOR
43 public char *   editor;
44 public char *   editproto;
45 #endif
46 
47 #if TAGS
48 extern char *   tags;
49 extern char *   tagoption;
50 extern int      jump_sline;
51 #endif
52 
53 #ifdef WIN32
54 static char consoleTitle[256];
55 #endif
56 
57 public int      one_screen;
58 extern int      less_is_more;
59 extern int      missing_cap;
60 extern int      know_dumb;
61 extern int      pr_type;
62 extern int      quit_if_one_screen;
63 extern int      no_init;
64 extern int      errmsgs;
65 extern int      redraw_on_quit;
66 extern int      term_init_done;
67 extern int      first_time;
68 
69 /*
70  * Entry point.
71  */
72 int main(int argc, char *argv[])
73 {
74 	IFILE ifile;
75 	char *s;
76 
77 #ifdef __EMX__
78 	_response(&argc, &argv);
79 	_wildcard(&argc, &argv);
80 #endif
81 
82 	progname = *argv++;
83 	argc--;
84 
85 #if SECURE
86 	secure = 1;
87 #else
88 	secure = 0;
89 	s = lgetenv("LESSSECURE");
90 	if (!isnullenv(s))
91 		secure = 1;
92 #endif
93 
94 #ifdef WIN32
95 	if (getenv("HOME") == NULL)
96 	{
97 		/*
98 		 * If there is no HOME environment variable,
99 		 * try the concatenation of HOMEDRIVE + HOMEPATH.
100 		 */
101 		char *drive = getenv("HOMEDRIVE");
102 		char *path  = getenv("HOMEPATH");
103 		if (drive != NULL && path != NULL)
104 		{
105 			char *env = (char *) ecalloc(strlen(drive) +
106 					strlen(path) + 6, sizeof(char));
107 			strcpy(env, "HOME=");
108 			strcat(env, drive);
109 			strcat(env, path);
110 			putenv(env);
111 		}
112 	}
113 	GetConsoleTitle(consoleTitle, sizeof(consoleTitle)/sizeof(char));
114 #endif /* WIN32 */
115 
116 	/*
117 	 * Process command line arguments and LESS environment arguments.
118 	 * Command line arguments override environment arguments.
119 	 */
120 	is_tty = isatty(1);
121 	init_mark();
122 	init_cmds();
123 	init_poll();
124 	get_term();
125 	init_charset();
126 	init_line();
127 	init_cmdhist();
128 	init_option();
129 	init_search();
130 
131 	/*
132 	 * If the name of the executable program is "more",
133 	 * act like LESS_IS_MORE is set.
134 	 */
135 	s = last_component(progname);
136 	if (strcmp(s, "more") == 0)
137 		less_is_more = 1;
138 
139 	init_prompt();
140 
141 	if (less_is_more)
142 		scan_option("-fG");
143 
144 	s = lgetenv(less_is_more ? "MORE" : "LESS");
145 	if (s != NULL)
146 		scan_option(s);
147 
148 #define isoptstring(s)  less_is_more ? (((s)[0] == '-') && (s)[1] != '\0') : \
149 			(((s)[0] == '-' || (s)[0] == '+') && (s)[1] != '\0')
150 	while (argc > 0 && (isoptstring(*argv) || isoptpending()))
151 	{
152 		s = *argv++;
153 		argc--;
154 		if (strcmp(s, "--") == 0)
155 			break;
156 		scan_option(s);
157 	}
158 #undef isoptstring
159 
160 	if (isoptpending())
161 	{
162 		/*
163 		 * Last command line option was a flag requiring a
164 		 * following string, but there was no following string.
165 		 */
166 		nopendopt();
167 		quit(QUIT_OK);
168 	}
169 
170 	if (less_is_more)
171 		no_init = TRUE;
172 
173 	expand_cmd_tables();
174 
175 #if EDITOR
176 	editor = lgetenv("VISUAL");
177 	if (editor == NULL || *editor == '\0')
178 	{
179 		editor = lgetenv("EDITOR");
180 		if (isnullenv(editor))
181 			editor = EDIT_PGM;
182 	}
183 	editproto = lgetenv("LESSEDIT");
184 	if (isnullenv(editproto))
185 		editproto = "%E ?lm+%lm. %g";
186 #endif
187 
188 	/*
189 	 * Call get_ifile with all the command line filenames
190 	 * to "register" them with the ifile system.
191 	 */
192 	ifile = NULL_IFILE;
193 	if (dohelp)
194 		ifile = get_ifile(FAKE_HELPFILE, ifile);
195 	while (argc-- > 0)
196 	{
197 #if (MSDOS_COMPILER && MSDOS_COMPILER != DJGPPC)
198 		/*
199 		 * Because the "shell" doesn't expand filename patterns,
200 		 * treat each argument as a filename pattern rather than
201 		 * a single filename.
202 		 * Expand the pattern and iterate over the expanded list.
203 		 */
204 		struct textlist tlist;
205 		char *filename;
206 		char *gfilename;
207 		char *qfilename;
208 
209 		gfilename = lglob(*argv++);
210 		init_textlist(&tlist, gfilename);
211 		filename = NULL;
212 		while ((filename = forw_textlist(&tlist, filename)) != NULL)
213 		{
214 			qfilename = shell_unquote(filename);
215 			(void) get_ifile(qfilename, ifile);
216 			free(qfilename);
217 			ifile = prev_ifile(NULL_IFILE);
218 		}
219 		free(gfilename);
220 #else
221 		(void) get_ifile(*argv++, ifile);
222 		ifile = prev_ifile(NULL_IFILE);
223 #endif
224 	}
225 	/*
226 	 * Set up terminal, etc.
227 	 */
228 	if (!is_tty)
229 	{
230 		/*
231 		 * Output is not a tty.
232 		 * Just copy the input file(s) to output.
233 		 */
234 		set_output(1); /* write to stdout */
235 		SET_BINARY(1);
236 		if (edit_first() == 0)
237 		{
238 			do {
239 				cat_file();
240 			} while (edit_next(1) == 0);
241 		}
242 		quit(QUIT_OK);
243 	}
244 
245 	if (missing_cap && !know_dumb && !less_is_more)
246 		error("WARNING: terminal is not fully functional", NULL_PARG);
247 	open_getchr();
248 	raw_mode(1);
249 	init_signals(1);
250 
251 	/*
252 	 * Select the first file to examine.
253 	 */
254 #if TAGS
255 	if (tagoption != NULL || strcmp(tags, "-") == 0)
256 	{
257 		/*
258 		 * A -t option was given.
259 		 * Verify that no filenames were also given.
260 		 * Edit the file selected by the "tags" search,
261 		 * and search for the proper line in the file.
262 		 */
263 		if (nifile() > 0)
264 		{
265 			error("No filenames allowed with -t option", NULL_PARG);
266 			quit(QUIT_ERROR);
267 		}
268 		findtag(tagoption);
269 		if (edit_tagfile())  /* Edit file which contains the tag */
270 			quit(QUIT_ERROR);
271 		/*
272 		 * Search for the line which contains the tag.
273 		 * Set up initial_scrpos so we display that line.
274 		 */
275 		initial_scrpos.pos = tagsearch();
276 		if (initial_scrpos.pos == NULL_POSITION)
277 			quit(QUIT_ERROR);
278 		initial_scrpos.ln = jump_sline;
279 	} else
280 #endif
281 	{
282 		if (edit_first())
283 			quit(QUIT_ERROR);
284 		/*
285 		 * See if file fits on one screen to decide whether
286 		 * to send terminal init. But don't need this
287 		 * if -X (no_init) overrides this (see init()).
288 		 */
289 		if (quit_if_one_screen)
290 		{
291 			if (nifile() > 1) /* If more than one file, -F cannot be used */
292 				quit_if_one_screen = FALSE;
293 			else if (!no_init)
294 				one_screen = get_one_screen();
295 		}
296 	}
297 
298 	if (errmsgs > 0)
299 	{
300 		/*
301 		 * We displayed some messages on error output
302 		 * (file descriptor 2; see flush()).
303 		 * Before erasing the screen contents, wait for a keystroke.
304 		 */
305 		less_printf("Press RETURN to continue ", NULL_PARG);
306 		get_return();
307 		putchr('\n');
308 	}
309 	set_output(1);
310 	init();
311 	commands();
312 	quit(QUIT_OK);
313 	/*NOTREACHED*/
314 	return (0);
315 }
316 
317 /*
318  * Copy a string to a "safe" place
319  * (that is, to a buffer allocated by calloc).
320  */
321 public char * save(constant char *s)
322 {
323 	char *p;
324 
325 	p = (char *) ecalloc(strlen(s)+1, sizeof(char));
326 	strcpy(p, s);
327 	return (p);
328 }
329 
330 public void out_of_memory(void)
331 {
332 	error("Cannot allocate memory", NULL_PARG);
333 	quit(QUIT_ERROR);
334 }
335 
336 /*
337  * Allocate memory.
338  * Like calloc(), but never returns an error (NULL).
339  */
340 public void * ecalloc(int count, unsigned int size)
341 {
342 	void * p;
343 
344 	p = (void *) calloc(count, size);
345 	if (p == NULL)
346 		out_of_memory();
347 	return p;
348 }
349 
350 /*
351  * Skip leading spaces in a string.
352  */
353 public char * skipsp(char *s)
354 {
355 	while (*s == ' ' || *s == '\t')
356 		s++;
357 	return (s);
358 }
359 
360 /*
361  * See how many characters of two strings are identical.
362  * If uppercase is true, the first string must begin with an uppercase
363  * character; the remainder of the first string may be either case.
364  */
365 public int sprefix(char *ps, char *s, int uppercase)
366 {
367 	int c;
368 	int sc;
369 	int len = 0;
370 
371 	for ( ;  *s != '\0';  s++, ps++)
372 	{
373 		c = *ps;
374 		if (uppercase)
375 		{
376 			if (len == 0 && ASCII_IS_LOWER(c))
377 				return (-1);
378 			if (ASCII_IS_UPPER(c))
379 				c = ASCII_TO_LOWER(c);
380 		}
381 		sc = *s;
382 		if (len > 0 && ASCII_IS_UPPER(sc))
383 			sc = ASCII_TO_LOWER(sc);
384 		if (c != sc)
385 			break;
386 		len++;
387 	}
388 	return (len);
389 }
390 
391 /*
392  * Exit the program.
393  */
394 public void quit(int status)
395 {
396 	static int save_status;
397 
398 	/*
399 	 * Put cursor at bottom left corner, clear the line,
400 	 * reset the terminal modes, and exit.
401 	 */
402 	if (status < 0)
403 		status = save_status;
404 	else
405 		save_status = status;
406 	quitting = 1;
407 	check_altpipe_error();
408 	if (interactive())
409 		clear_bot();
410 	deinit();
411 	flush();
412 	if (redraw_on_quit && term_init_done)
413 	{
414 		/*
415 		 * The last file text displayed might have been on an
416 		 * alternate screen, which now (since deinit) cannot be seen.
417 		 * redraw_on_quit tells us to redraw it on the main screen.
418 		 */
419 		first_time = 1; /* Don't print "skipping" or tildes */
420 		repaint();
421 		flush();
422 	}
423 	edit((char*)NULL);
424 	save_cmdhist();
425 	raw_mode(0);
426 #if MSDOS_COMPILER && MSDOS_COMPILER != DJGPPC
427 	/*
428 	 * If we don't close 2, we get some garbage from
429 	 * 2's buffer when it flushes automatically.
430 	 * I cannot track this one down  RB
431 	 * The same bug shows up if we use ^C^C to abort.
432 	 */
433 	close(2);
434 #endif
435 #ifdef WIN32
436 	SetConsoleTitle(consoleTitle);
437 #endif
438 	close_getchr();
439 	exit(status);
440 }
441