1 /* vi: set sw=4 ts=4: */
2 /*
3 * Mini less implementation for busybox
4 *
5 * Copyright (C) 2005 by Rob Sullivan <cogito.ergo.cogito@gmail.com>
6 *
7 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
8 */
9
10 /*
11 * TODO:
12 * - Add more regular expression support - search modifiers, certain matches, etc.
13 * - Add more complex bracket searching - currently, nested brackets are
14 * not considered.
15 * - Add support for "F" as an input. This causes less to act in
16 * a similar way to tail -f.
17 * - Allow horizontal scrolling.
18 *
19 * Notes:
20 * - the inp file pointer is used so that keyboard input works after
21 * redirected input has been read from stdin
22 */
23
24 //config:config LESS
25 //config: bool "less"
26 //config: default y
27 //config: help
28 //config: 'less' is a pager, meaning that it displays text files. It possesses
29 //config: a wide array of features, and is an improvement over 'more'.
30 //config:
31 //config:config FEATURE_LESS_MAXLINES
32 //config: int "Max number of input lines less will try to eat"
33 //config: default 9999999
34 //config: depends on LESS
35 //config:
36 //config:config FEATURE_LESS_BRACKETS
37 //config: bool "Enable bracket searching"
38 //config: default y
39 //config: depends on LESS
40 //config: help
41 //config: This option adds the capability to search for matching left and right
42 //config: brackets, facilitating programming.
43 //config:
44 //config:config FEATURE_LESS_FLAGS
45 //config: bool "Enable -m/-M"
46 //config: default y
47 //config: depends on LESS
48 //config: help
49 //config: The -M/-m flag enables a more sophisticated status line.
50 //config:
51 //config:config FEATURE_LESS_TRUNCATE
52 //config: bool "Enable -S"
53 //config: default y
54 //config: depends on LESS
55 //config: help
56 //config: The -S flag causes long lines to be truncated rather than
57 //config: wrapped.
58 //config:
59 //config:config FEATURE_LESS_MARKS
60 //config: bool "Enable marks"
61 //config: default y
62 //config: depends on LESS
63 //config: help
64 //config: Marks enable positions in a file to be stored for easy reference.
65 //config:
66 //config:config FEATURE_LESS_REGEXP
67 //config: bool "Enable regular expressions"
68 //config: default y
69 //config: depends on LESS
70 //config: help
71 //config: Enable regular expressions, allowing complex file searches.
72 //config:
73 //config:config FEATURE_LESS_WINCH
74 //config: bool "Enable automatic resizing on window size changes"
75 //config: default y
76 //config: depends on LESS
77 //config: help
78 //config: Makes less track window size changes.
79 //config:
80 //config:config FEATURE_LESS_ASK_TERMINAL
81 //config: bool "Use 'tell me cursor position' ESC sequence to measure window"
82 //config: default y
83 //config: depends on FEATURE_LESS_WINCH
84 //config: help
85 //config: Makes less track window size changes.
86 //config: If terminal size can't be retrieved and $LINES/$COLUMNS are not set,
87 //config: this option makes less perform a last-ditch effort to find it:
88 //config: position cursor to 999,999 and ask terminal to report real
89 //config: cursor position using "ESC [ 6 n" escape sequence, then read stdin.
90 //config:
91 //config: This is not clean but helps a lot on serial lines and such.
92 //config:
93 //config:config FEATURE_LESS_DASHCMD
94 //config: bool "Enable flag changes ('-' command)"
95 //config: default y
96 //config: depends on LESS
97 //config: help
98 //config: This enables the ability to change command-line flags within
99 //config: less itself ('-' keyboard command).
100 //config:
101 //config:config FEATURE_LESS_LINENUMS
102 //config: bool "Enable dynamic switching of line numbers"
103 //config: default y
104 //config: depends on FEATURE_LESS_DASHCMD
105 //config: help
106 //config: Enables "-N" command.
107
108 //applet:IF_LESS(APPLET(less, BB_DIR_USR_BIN, BB_SUID_DROP))
109
110 //kbuild:lib-$(CONFIG_LESS) += less.o
111
112 //usage:#define less_trivial_usage
113 //usage: "[-E" IF_FEATURE_LESS_REGEXP("I")IF_FEATURE_LESS_FLAGS("Mm")
114 //usage: "N" IF_FEATURE_LESS_TRUNCATE("S") "h~] [FILE]..."
115 //usage:#define less_full_usage "\n\n"
116 //usage: "View FILE (or stdin) one screenful at a time\n"
117 //usage: "\n -E Quit once the end of a file is reached"
118 //usage: IF_FEATURE_LESS_REGEXP(
119 //usage: "\n -I Ignore case in all searches"
120 //usage: )
121 //usage: IF_FEATURE_LESS_FLAGS(
122 //usage: "\n -M,-m Display status line with line numbers"
123 //usage: "\n and percentage through the file"
124 //usage: )
125 //usage: "\n -N Prefix line number to each line"
126 //usage: IF_FEATURE_LESS_TRUNCATE(
127 //usage: "\n -S Truncate long lines"
128 //usage: )
129 //usage: "\n -~ Suppress ~s displayed past EOF"
130
131 #include <sched.h> /* sched_yield() */
132
133 #include "libbb.h"
134 #include "common_bufsiz.h"
135 #if ENABLE_FEATURE_LESS_REGEXP
136 #include "xregex.h"
137 #endif
138
139
140 #define ESC "\033"
141 /* The escape codes for highlighted and normal text */
142 #define HIGHLIGHT ESC"[7m"
143 #define NORMAL ESC"[0m"
144 /* The escape code to home and clear to the end of screen */
145 #define CLEAR ESC"[H\033[J"
146 /* The escape code to clear to the end of line */
147 #define CLEAR_2_EOL ESC"[K"
148
149 enum {
150 /* Absolute max of lines eaten */
151 MAXLINES = CONFIG_FEATURE_LESS_MAXLINES,
152 /* This many "after the end" lines we will show (at max) */
153 TILDES = 1,
154 };
155
156 /* Command line options */
157 enum {
158 FLAG_E = 1 << 0,
159 FLAG_M = 1 << 1,
160 FLAG_m = 1 << 2,
161 FLAG_N = 1 << 3,
162 FLAG_TILDE = 1 << 4,
163 FLAG_I = 1 << 5,
164 FLAG_S = (1 << 6) * ENABLE_FEATURE_LESS_TRUNCATE,
165 /* hijack command line options variable for internal state vars */
166 LESS_STATE_MATCH_BACKWARDS = 1 << 15,
167 };
168
169 #if !ENABLE_FEATURE_LESS_REGEXP
170 enum { pattern_valid = 0 };
171 #endif
172
173 struct globals {
174 int cur_fline; /* signed */
175 int kbd_fd; /* fd to get input from */
176 int kbd_fd_orig_flags;
177 int less_gets_pos;
178 /* last position in last line, taking into account tabs */
179 size_t last_line_pos;
180 unsigned max_fline;
181 unsigned max_lineno; /* this one tracks linewrap */
182 unsigned max_displayed_line;
183 unsigned width;
184 #if ENABLE_FEATURE_LESS_WINCH
185 unsigned winch_counter;
186 #endif
187 ssize_t eof_error; /* eof if 0, error if < 0 */
188 ssize_t readpos;
189 ssize_t readeof; /* must be signed */
190 const char **buffer;
191 const char **flines;
192 const char *empty_line_marker;
193 unsigned num_files;
194 unsigned current_file;
195 char *filename;
196 char **files;
197 #if ENABLE_FEATURE_LESS_FLAGS
198 int num_lines; /* a flag if < 0, line count if >= 0 */
199 # define REOPEN_AND_COUNT (-1)
200 # define REOPEN_STDIN (-2)
201 # define NOT_REGULAR_FILE (-3)
202 #endif
203 #if ENABLE_FEATURE_LESS_MARKS
204 unsigned num_marks;
205 unsigned mark_lines[15][2];
206 #endif
207 #if ENABLE_FEATURE_LESS_REGEXP
208 unsigned *match_lines;
209 int match_pos; /* signed! */
210 int wanted_match; /* signed! */
211 int num_matches;
212 regex_t pattern;
213 smallint pattern_valid;
214 #endif
215 #if ENABLE_FEATURE_LESS_ASK_TERMINAL
216 smallint winsize_err;
217 #endif
218 smallint terminated;
219 struct termios term_orig, term_less;
220 char kbd_input[KEYCODE_BUFFER_SIZE];
221 };
222 #define G (*ptr_to_globals)
223 #define cur_fline (G.cur_fline )
224 #define kbd_fd (G.kbd_fd )
225 #define less_gets_pos (G.less_gets_pos )
226 #define last_line_pos (G.last_line_pos )
227 #define max_fline (G.max_fline )
228 #define max_lineno (G.max_lineno )
229 #define max_displayed_line (G.max_displayed_line)
230 #define width (G.width )
231 #define winch_counter (G.winch_counter )
232 /* This one is 100% not cached by compiler on read access */
233 #define WINCH_COUNTER (*(volatile unsigned *)&winch_counter)
234 #define eof_error (G.eof_error )
235 #define readpos (G.readpos )
236 #define readeof (G.readeof )
237 #define buffer (G.buffer )
238 #define flines (G.flines )
239 #define empty_line_marker (G.empty_line_marker )
240 #define num_files (G.num_files )
241 #define current_file (G.current_file )
242 #define filename (G.filename )
243 #define files (G.files )
244 #define num_lines (G.num_lines )
245 #define num_marks (G.num_marks )
246 #define mark_lines (G.mark_lines )
247 #if ENABLE_FEATURE_LESS_REGEXP
248 #define match_lines (G.match_lines )
249 #define match_pos (G.match_pos )
250 #define num_matches (G.num_matches )
251 #define wanted_match (G.wanted_match )
252 #define pattern (G.pattern )
253 #define pattern_valid (G.pattern_valid )
254 #endif
255 #define terminated (G.terminated )
256 #define term_orig (G.term_orig )
257 #define term_less (G.term_less )
258 #define kbd_input (G.kbd_input )
259 #define INIT_G() do { \
260 SET_PTR_TO_GLOBALS(xzalloc(sizeof(G))); \
261 less_gets_pos = -1; \
262 empty_line_marker = "~"; \
263 num_files = 1; \
264 current_file = 1; \
265 eof_error = 1; \
266 terminated = 1; \
267 IF_FEATURE_LESS_REGEXP(wanted_match = -1;) \
268 } while (0)
269
270 /* flines[] are lines read from stdin, each in malloc'ed buffer.
271 * Line numbers are stored as uint32_t prepended to each line.
272 * Pointer is adjusted so that flines[i] points directly past
273 * line number. Accesor: */
274 #define MEMPTR(p) ((char*)(p) - 4)
275 #define LINENO(p) (*(uint32_t*)((p) - 4))
276
277
278 /* Reset terminal input to normal */
set_tty_cooked(void)279 static void set_tty_cooked(void)
280 {
281 fflush_all();
282 tcsetattr(kbd_fd, TCSANOW, &term_orig);
283 }
284
285 /* Move the cursor to a position (x,y), where (0,0) is the
286 top-left corner of the console */
move_cursor(int line,int row)287 static void move_cursor(int line, int row)
288 {
289 printf(ESC"[%u;%uH", line, row);
290 }
291
clear_line(void)292 static void clear_line(void)
293 {
294 printf(ESC"[%u;0H" CLEAR_2_EOL, max_displayed_line + 2);
295 }
296
print_hilite(const char * str)297 static void print_hilite(const char *str)
298 {
299 printf(HIGHLIGHT"%s"NORMAL, str);
300 }
301
print_statusline(const char * str)302 static void print_statusline(const char *str)
303 {
304 clear_line();
305 printf(HIGHLIGHT"%.*s"NORMAL, width - 1, str);
306 }
307
308 /* Exit the program gracefully */
less_exit(int code)309 static void less_exit(int code)
310 {
311 set_tty_cooked();
312 if (!(G.kbd_fd_orig_flags & O_NONBLOCK))
313 ndelay_off(kbd_fd);
314 clear_line();
315 if (code < 0)
316 kill_myself_with_sig(- code); /* does not return */
317 exit(code);
318 }
319
320 #if (ENABLE_FEATURE_LESS_DASHCMD && ENABLE_FEATURE_LESS_LINENUMS) \
321 || ENABLE_FEATURE_LESS_WINCH
re_wrap(void)322 static void re_wrap(void)
323 {
324 int w = width;
325 int new_line_pos;
326 int src_idx;
327 int dst_idx;
328 int new_cur_fline = 0;
329 uint32_t lineno;
330 char linebuf[w + 1];
331 const char **old_flines = flines;
332 const char *s;
333 char **new_flines = NULL;
334 char *d;
335
336 if (option_mask32 & FLAG_N)
337 w -= 8;
338
339 src_idx = 0;
340 dst_idx = 0;
341 s = old_flines[0];
342 lineno = LINENO(s);
343 d = linebuf;
344 new_line_pos = 0;
345 while (1) {
346 *d = *s;
347 if (*d != '\0') {
348 new_line_pos++;
349 if (*d == '\t') { /* tab */
350 new_line_pos += 7;
351 new_line_pos &= (~7);
352 }
353 s++;
354 d++;
355 if (new_line_pos >= w) {
356 int sz;
357 /* new line is full, create next one */
358 *d = '\0';
359 next_new:
360 sz = (d - linebuf) + 1; /* + 1: NUL */
361 d = ((char*)xmalloc(sz + 4)) + 4;
362 LINENO(d) = lineno;
363 memcpy(d, linebuf, sz);
364 new_flines = xrealloc_vector(new_flines, 8, dst_idx);
365 new_flines[dst_idx] = d;
366 dst_idx++;
367 if (new_line_pos < w) {
368 /* if we came here thru "goto next_new" */
369 if (src_idx > max_fline)
370 break;
371 lineno = LINENO(s);
372 }
373 d = linebuf;
374 new_line_pos = 0;
375 }
376 continue;
377 }
378 /* *d == NUL: old line ended, go to next old one */
379 free(MEMPTR(old_flines[src_idx]));
380 /* btw, convert cur_fline... */
381 if (cur_fline == src_idx)
382 new_cur_fline = dst_idx;
383 src_idx++;
384 /* no more lines? finish last new line (and exit the loop) */
385 if (src_idx > max_fline)
386 goto next_new;
387 s = old_flines[src_idx];
388 if (lineno != LINENO(s)) {
389 /* this is not a continuation line!
390 * create next _new_ line too */
391 goto next_new;
392 }
393 }
394
395 free(old_flines);
396 flines = (const char **)new_flines;
397
398 max_fline = dst_idx - 1;
399 last_line_pos = new_line_pos;
400 cur_fline = new_cur_fline;
401 /* max_lineno is screen-size independent */
402 #if ENABLE_FEATURE_LESS_REGEXP
403 pattern_valid = 0;
404 #endif
405 }
406 #endif
407
408 #if ENABLE_FEATURE_LESS_REGEXP
409 static void fill_match_lines(unsigned pos);
410 #else
411 #define fill_match_lines(pos) ((void)0)
412 #endif
413
at_end(void)414 static int at_end(void)
415 {
416 return (option_mask32 & FLAG_S)
417 ? !(cur_fline <= max_fline &&
418 max_lineno > LINENO(flines[cur_fline]) + max_displayed_line)
419 : !(max_fline > cur_fline + max_displayed_line);
420 }
421
422 /* Devilishly complex routine.
423 *
424 * Has to deal with EOF and EPIPE on input,
425 * with line wrapping, with last line not ending in '\n'
426 * (possibly not ending YET!), with backspace and tabs.
427 * It reads input again if last time we got an EOF (thus supporting
428 * growing files) or EPIPE (watching output of slow process like make).
429 *
430 * Variables used:
431 * flines[] - array of lines already read. Linewrap may cause
432 * one source file line to occupy several flines[n].
433 * flines[max_fline] - last line, possibly incomplete.
434 * terminated - 1 if flines[max_fline] is 'terminated'
435 * (if there was '\n' [which isn't stored itself, we just remember
436 * that it was seen])
437 * max_lineno - last line's number, this one doesn't increment
438 * on line wrap, only on "real" new lines.
439 * readbuf[0..readeof-1] - small preliminary buffer.
440 * readbuf[readpos] - next character to add to current line.
441 * last_line_pos - screen line position of next char to be read
442 * (takes into account tabs and backspaces)
443 * eof_error - < 0 error, == 0 EOF, > 0 not EOF/error
444 *
445 * "git log -p | less -m" on the kernel git tree is a good test for EAGAINs,
446 * "/search on very long input" and "reaching max line count" corner cases.
447 */
read_lines(void)448 static void read_lines(void)
449 {
450 char *current_line, *p;
451 int w = width;
452 char last_terminated = terminated;
453 time_t last_time = 0;
454 int retry_EAGAIN = 2;
455 #if ENABLE_FEATURE_LESS_REGEXP
456 unsigned old_max_fline = max_fline;
457 #endif
458
459 #define readbuf bb_common_bufsiz1
460 setup_common_bufsiz();
461
462 /* (careful: max_fline can be -1) */
463 if (max_fline + 1 > MAXLINES)
464 return;
465
466 if (option_mask32 & FLAG_N)
467 w -= 8;
468
469 p = current_line = ((char*)xmalloc(w + 5)) + 4;
470 if (!last_terminated) {
471 const char *cp = flines[max_fline];
472 p = stpcpy(p, cp);
473 free(MEMPTR(cp));
474 /* last_line_pos is still valid from previous read_lines() */
475 } else {
476 max_fline++;
477 last_line_pos = 0;
478 }
479
480 while (1) { /* read lines until we reach cur_fline or wanted_match */
481 *p = '\0';
482 terminated = 0;
483 while (1) { /* read chars until we have a line */
484 char c;
485 /* if no unprocessed chars left, eat more */
486 if (readpos >= readeof) {
487 int flags = ndelay_on(0);
488
489 while (1) {
490 time_t t;
491
492 errno = 0;
493 eof_error = safe_read(STDIN_FILENO, readbuf, COMMON_BUFSIZE);
494 if (errno != EAGAIN)
495 break;
496 t = time(NULL);
497 if (t != last_time) {
498 last_time = t;
499 if (--retry_EAGAIN < 0)
500 break;
501 }
502 sched_yield();
503 }
504 fcntl(0, F_SETFL, flags); /* ndelay_off(0) */
505 readpos = 0;
506 readeof = eof_error;
507 if (eof_error <= 0)
508 goto reached_eof;
509 retry_EAGAIN = 1;
510 }
511 c = readbuf[readpos];
512 /* backspace? [needed for manpages] */
513 /* <tab><bs> is (a) insane and */
514 /* (b) harder to do correctly, so we refuse to do it */
515 if (c == '\x8' && last_line_pos && p[-1] != '\t') {
516 readpos++; /* eat it */
517 last_line_pos--;
518 /* was buggy (p could end up <= current_line)... */
519 *--p = '\0';
520 continue;
521 }
522 {
523 size_t new_last_line_pos = last_line_pos + 1;
524 if (c == '\t') {
525 new_last_line_pos += 7;
526 new_last_line_pos &= (~7);
527 }
528 if ((int)new_last_line_pos > w)
529 break;
530 last_line_pos = new_last_line_pos;
531 }
532 /* ok, we will eat this char */
533 readpos++;
534 if (c == '\n') {
535 terminated = 1;
536 last_line_pos = 0;
537 break;
538 }
539 /* NUL is substituted by '\n'! */
540 if (c == '\0') c = '\n';
541 *p++ = c;
542 *p = '\0';
543 } /* end of "read chars until we have a line" loop */
544 #if 0
545 //BUG: also triggers on this:
546 // { printf "\nfoo\n"; sleep 1; printf "\nbar\n"; } | less
547 // (resulting in lost empty line between "foo" and "bar" lines)
548 // the "terminated" logic needs fixing (or explaining)
549 /* Corner case: linewrap with only "" wrapping to next line */
550 /* Looks ugly on screen, so we do not store this empty line */
551 if (!last_terminated && !current_line[0]) {
552 last_terminated = 1;
553 max_lineno++;
554 continue;
555 }
556 #endif
557 reached_eof:
558 last_terminated = terminated;
559 flines = xrealloc_vector(flines, 8, max_fline);
560
561 flines[max_fline] = (char*)xrealloc(MEMPTR(current_line), strlen(current_line) + 1 + 4) + 4;
562 LINENO(flines[max_fline]) = max_lineno;
563 if (terminated)
564 max_lineno++;
565
566 if (max_fline >= MAXLINES) {
567 eof_error = 0; /* Pretend we saw EOF */
568 break;
569 }
570 if (!at_end()) {
571 #if !ENABLE_FEATURE_LESS_REGEXP
572 break;
573 #else
574 if (wanted_match >= num_matches) { /* goto_match called us */
575 fill_match_lines(old_max_fline);
576 old_max_fline = max_fline;
577 }
578 if (wanted_match < num_matches)
579 break;
580 #endif
581 }
582 if (eof_error <= 0) {
583 break;
584 }
585 max_fline++;
586 current_line = ((char*)xmalloc(w + 5)) + 4;
587 p = current_line;
588 last_line_pos = 0;
589 } /* end of "read lines until we reach cur_fline" loop */
590
591 if (eof_error < 0) {
592 if (errno == EAGAIN) {
593 eof_error = 1;
594 } else {
595 print_statusline(bb_msg_read_error);
596 }
597 }
598 #if ENABLE_FEATURE_LESS_FLAGS
599 else if (eof_error == 0)
600 num_lines = max_lineno;
601 #endif
602
603 fill_match_lines(old_max_fline);
604 #if ENABLE_FEATURE_LESS_REGEXP
605 /* prevent us from being stuck in search for a match */
606 wanted_match = -1;
607 #endif
608 #undef readbuf
609 }
610
611 #if ENABLE_FEATURE_LESS_FLAGS
safe_lineno(int fline)612 static int safe_lineno(int fline)
613 {
614 if (fline >= max_fline)
615 fline = max_fline - 1;
616
617 /* also catches empty file (max_fline == 0) */
618 if (fline < 0)
619 return 0;
620
621 return LINENO(flines[fline]) + 1;
622 }
623
624 /* count number of lines in file */
update_num_lines(void)625 static void update_num_lines(void)
626 {
627 int count, fd;
628 struct stat stbuf;
629 ssize_t len, i;
630 char buf[4096];
631
632 /* only do this for regular files */
633 if (num_lines == REOPEN_AND_COUNT || num_lines == REOPEN_STDIN) {
634 count = 0;
635 fd = open("/proc/self/fd/0", O_RDONLY);
636 if (fd < 0 && num_lines == REOPEN_AND_COUNT) {
637 /* "filename" is valid only if REOPEN_AND_COUNT */
638 fd = open(filename, O_RDONLY);
639 }
640 if (fd < 0) {
641 /* somebody stole my file! */
642 num_lines = NOT_REGULAR_FILE;
643 return;
644 }
645 if (fstat(fd, &stbuf) != 0 || !S_ISREG(stbuf.st_mode)) {
646 num_lines = NOT_REGULAR_FILE;
647 goto do_close;
648 }
649 while ((len = safe_read(fd, buf, sizeof(buf))) > 0) {
650 for (i = 0; i < len; ++i) {
651 if (buf[i] == '\n' && ++count == MAXLINES)
652 goto done;
653 }
654 }
655 done:
656 num_lines = count;
657 do_close:
658 close(fd);
659 }
660 }
661
662 /* Print a status line if -M was specified */
m_status_print(void)663 static void m_status_print(void)
664 {
665 int first, last;
666 unsigned percent;
667
668 if (less_gets_pos >= 0) /* don't touch statusline while input is done! */
669 return;
670
671 clear_line();
672 printf(HIGHLIGHT"%s", filename);
673 if (num_files > 1)
674 printf(" (file %i of %i)", current_file, num_files);
675
676 first = safe_lineno(cur_fline);
677 last = (option_mask32 & FLAG_S)
678 ? MIN(first + max_displayed_line, max_lineno)
679 : safe_lineno(cur_fline + max_displayed_line);
680 printf(" lines %i-%i", first, last);
681
682 update_num_lines();
683 if (num_lines >= 0)
684 printf("/%i", num_lines);
685
686 if (at_end()) {
687 printf(" (END)");
688 if (num_files > 1 && current_file != num_files)
689 printf(" - next: %s", files[current_file]);
690 } else if (num_lines > 0) {
691 percent = (100 * last + num_lines/2) / num_lines;
692 printf(" %i%%", percent <= 100 ? percent : 100);
693 }
694 printf(NORMAL);
695 }
696 #endif
697
698 /* Print the status line */
status_print(void)699 static void status_print(void)
700 {
701 const char *p;
702
703 if (less_gets_pos >= 0) /* don't touch statusline while input is done! */
704 return;
705
706 /* Change the status if flags have been set */
707 #if ENABLE_FEATURE_LESS_FLAGS
708 if (option_mask32 & (FLAG_M|FLAG_m)) {
709 m_status_print();
710 return;
711 }
712 /* No flags set */
713 #endif
714
715 clear_line();
716 if (cur_fline && !at_end()) {
717 bb_putchar(':');
718 return;
719 }
720 p = "(END)";
721 if (!cur_fline)
722 p = filename;
723 if (num_files > 1) {
724 printf(HIGHLIGHT"%s (file %i of %i)"NORMAL,
725 p, current_file, num_files);
726 return;
727 }
728 print_hilite(p);
729 }
730
731 static const char controls[] ALIGN1 =
732 /* NUL: never encountered; TAB: not converted */
733 /**/"\x01\x02\x03\x04\x05\x06\x07\x08" "\x0a\x0b\x0c\x0d\x0e\x0f"
734 "\x10\x11\x12\x13\x14\x15\x16\x17\x18\x19\x1a\x1b\x1c\x1d\x1e\x1f"
735 "\x7f\x9b"; /* DEL and infamous Meta-ESC :( */
736 static const char ctrlconv[] ALIGN1 =
737 /* why 40 instead of 4a below? - it is a replacement for '\n'.
738 * '\n' is a former NUL - we subst it with @, not J */
739 "\x40\x41\x42\x43\x44\x45\x46\x47\x48\x49\x40\x4b\x4c\x4d\x4e\x4f"
740 "\x50\x51\x52\x53\x54\x55\x56\x57\x58\x59\x5a\x5b\x5c\x5d\x5e\x5f";
741
print_lineno(const char * line)742 static void print_lineno(const char *line)
743 {
744 const char *fmt = " ";
745 unsigned n = n; /* for compiler */
746
747 if (line != empty_line_marker) {
748 /* Width of 7 preserves tab spacing in the text */
749 fmt = "%7u ";
750 n = LINENO(line) + 1;
751 if (n > 9999999 && MAXLINES > 9999999) {
752 n %= 10000000;
753 fmt = "%07u ";
754 }
755 }
756 printf(fmt, n);
757 }
758
759
760 #if ENABLE_FEATURE_LESS_REGEXP
print_found(const char * line)761 static void print_found(const char *line)
762 {
763 int match_status;
764 int eflags;
765 char *growline;
766 regmatch_t match_structs;
767
768 char buf[width+1];
769 const char *str = line;
770 char *p = buf;
771 size_t n;
772
773 while (*str) {
774 n = strcspn(str, controls);
775 if (n) {
776 if (!str[n]) break;
777 memcpy(p, str, n);
778 p += n;
779 str += n;
780 }
781 n = strspn(str, controls);
782 memset(p, '.', n);
783 p += n;
784 str += n;
785 }
786 strcpy(p, str);
787
788 /* buf[] holds quarantined version of str */
789
790 /* Each part of the line that matches has the HIGHLIGHT
791 * and NORMAL escape sequences placed around it.
792 * NB: we regex against line, but insert text
793 * from quarantined copy (buf[]) */
794 str = buf;
795 growline = NULL;
796 eflags = 0;
797 goto start;
798
799 while (match_status == 0) {
800 char *new = xasprintf("%s%.*s"HIGHLIGHT"%.*s"NORMAL,
801 growline ? growline : "",
802 (int)match_structs.rm_so, str,
803 (int)(match_structs.rm_eo - match_structs.rm_so),
804 str + match_structs.rm_so);
805 free(growline);
806 growline = new;
807 str += match_structs.rm_eo;
808 line += match_structs.rm_eo;
809 eflags = REG_NOTBOL;
810 start:
811 /* Most of the time doesn't find the regex, optimize for that */
812 match_status = regexec(&pattern, line, 1, &match_structs, eflags);
813 /* if even "" matches, treat it as "not a match" */
814 if (match_structs.rm_so >= match_structs.rm_eo)
815 match_status = 1;
816 }
817
818 printf("%s%s\n", growline ? growline : "", str);
819 free(growline);
820 }
821 #else
822 void print_found(const char *line);
823 #endif
824
print_ascii(const char * str)825 static void print_ascii(const char *str)
826 {
827 char buf[width+1];
828 char *p;
829 size_t n;
830
831 while (*str) {
832 n = strcspn(str, controls);
833 if (n) {
834 if (!str[n]) break;
835 printf("%.*s", (int) n, str);
836 str += n;
837 }
838 n = strspn(str, controls);
839 p = buf;
840 do {
841 if (*str == 0x7f)
842 *p++ = '?';
843 else if (*str == (char)0x9b)
844 /* VT100's CSI, aka Meta-ESC. Who's inventor? */
845 /* I want to know who committed this sin */
846 *p++ = '{';
847 else
848 *p++ = ctrlconv[(unsigned char)*str];
849 str++;
850 } while (--n);
851 *p = '\0';
852 print_hilite(buf);
853 }
854 puts(str);
855 }
856
857 /* Print the buffer */
buffer_print(void)858 static void buffer_print(void)
859 {
860 unsigned i;
861
862 move_cursor(0, 0);
863 for (i = 0; i <= max_displayed_line; i++) {
864 printf(CLEAR_2_EOL);
865 if (option_mask32 & FLAG_N)
866 print_lineno(buffer[i]);
867 if (pattern_valid)
868 print_found(buffer[i]);
869 else
870 print_ascii(buffer[i]);
871 }
872 if ((option_mask32 & FLAG_E)
873 && eof_error <= 0
874 && (max_fline - cur_fline) <= max_displayed_line
875 ) {
876 less_exit(EXIT_SUCCESS);
877 }
878 status_print();
879 }
880
buffer_fill_and_print(void)881 static void buffer_fill_and_print(void)
882 {
883 unsigned i;
884 #if ENABLE_FEATURE_LESS_TRUNCATE
885 int fpos = cur_fline;
886
887 if (option_mask32 & FLAG_S) {
888 /* Go back to the beginning of this line */
889 while (fpos && LINENO(flines[fpos]) == LINENO(flines[fpos-1]))
890 fpos--;
891 }
892
893 i = 0;
894 while (i <= max_displayed_line && fpos <= max_fline) {
895 int lineno = LINENO(flines[fpos]);
896 buffer[i] = flines[fpos];
897 i++;
898 do {
899 fpos++;
900 } while ((fpos <= max_fline)
901 && (option_mask32 & FLAG_S)
902 && lineno == LINENO(flines[fpos])
903 );
904 }
905 #else
906 for (i = 0; i <= max_displayed_line && cur_fline + i <= max_fline; i++) {
907 buffer[i] = flines[cur_fline + i];
908 }
909 #endif
910 for (; i <= max_displayed_line; i++) {
911 buffer[i] = empty_line_marker;
912 }
913 buffer_print();
914 }
915
916 /* move cur_fline to a given line number, reading lines if necessary */
goto_lineno(int target)917 static void goto_lineno(int target)
918 {
919 if (target <= 0 ) {
920 cur_fline = 0;
921 }
922 else if (target > LINENO(flines[cur_fline])) {
923 retry:
924 while (LINENO(flines[cur_fline]) != target && cur_fline < max_fline)
925 ++cur_fline;
926 /* target not reached but more input is available */
927 if (LINENO(flines[cur_fline]) != target && eof_error > 0) {
928 read_lines();
929 goto retry;
930 }
931 }
932 else {
933 /* search backwards through already-read lines */
934 while (LINENO(flines[cur_fline]) != target && cur_fline > 0)
935 --cur_fline;
936 }
937 }
938
cap_cur_fline(void)939 static void cap_cur_fline(void)
940 {
941 if ((option_mask32 & FLAG_S)) {
942 if (cur_fline > max_fline)
943 cur_fline = max_fline;
944 if (LINENO(flines[cur_fline]) + max_displayed_line > max_lineno + TILDES) {
945 goto_lineno(max_lineno - max_displayed_line + TILDES);
946 read_lines();
947 }
948 }
949 else {
950 if (cur_fline + max_displayed_line > max_fline + TILDES)
951 cur_fline = max_fline - max_displayed_line + TILDES;
952 if (cur_fline < 0)
953 cur_fline = 0;
954 }
955 }
956
957 /* Move the buffer up and down in the file in order to scroll */
buffer_down(int nlines)958 static void buffer_down(int nlines)
959 {
960 if ((option_mask32 & FLAG_S))
961 goto_lineno(LINENO(flines[cur_fline]) + nlines);
962 else
963 cur_fline += nlines;
964 read_lines();
965 cap_cur_fline();
966 buffer_fill_and_print();
967 }
968
buffer_up(int nlines)969 static void buffer_up(int nlines)
970 {
971 if ((option_mask32 & FLAG_S)) {
972 goto_lineno(LINENO(flines[cur_fline]) - nlines);
973 }
974 else {
975 cur_fline -= nlines;
976 if (cur_fline < 0)
977 cur_fline = 0;
978 }
979 read_lines();
980 buffer_fill_and_print();
981 }
982
983 /* display a given line where the argument can be either an index into
984 * the flines array or a line number */
buffer_to_line(int linenum,int is_lineno)985 static void buffer_to_line(int linenum, int is_lineno)
986 {
987 if (linenum <= 0)
988 cur_fline = 0;
989 else if (is_lineno)
990 goto_lineno(linenum);
991 else
992 cur_fline = linenum;
993 read_lines();
994 cap_cur_fline();
995 buffer_fill_and_print();
996 }
997
buffer_line(int linenum)998 static void buffer_line(int linenum)
999 {
1000 buffer_to_line(linenum, FALSE);
1001 }
1002
buffer_lineno(int lineno)1003 static void buffer_lineno(int lineno)
1004 {
1005 buffer_to_line(lineno, TRUE);
1006 }
1007
open_file_and_read_lines(void)1008 static void open_file_and_read_lines(void)
1009 {
1010 if (filename) {
1011 xmove_fd(xopen(filename, O_RDONLY), STDIN_FILENO);
1012 #if ENABLE_FEATURE_LESS_FLAGS
1013 num_lines = REOPEN_AND_COUNT;
1014 #endif
1015 } else {
1016 /* "less" with no arguments in argv[] */
1017 /* For status line only */
1018 filename = xstrdup(bb_msg_standard_input);
1019 #if ENABLE_FEATURE_LESS_FLAGS
1020 num_lines = REOPEN_STDIN;
1021 #endif
1022 }
1023 readpos = 0;
1024 readeof = 0;
1025 last_line_pos = 0;
1026 terminated = 1;
1027 read_lines();
1028 }
1029
1030 /* Reinitialize everything for a new file - free the memory and start over */
reinitialize(void)1031 static void reinitialize(void)
1032 {
1033 unsigned i;
1034
1035 if (flines) {
1036 for (i = 0; i <= max_fline; i++)
1037 free(MEMPTR(flines[i]));
1038 free(flines);
1039 flines = NULL;
1040 }
1041
1042 max_fline = -1;
1043 cur_fline = 0;
1044 max_lineno = 0;
1045 open_file_and_read_lines();
1046 #if ENABLE_FEATURE_LESS_ASK_TERMINAL
1047 if (G.winsize_err)
1048 printf("\033[999;999H" "\033[6n");
1049 #endif
1050 buffer_fill_and_print();
1051 }
1052
getch_nowait(void)1053 static int64_t getch_nowait(void)
1054 {
1055 int rd;
1056 int64_t key64;
1057 struct pollfd pfd[2];
1058
1059 pfd[0].fd = STDIN_FILENO;
1060 pfd[0].events = POLLIN;
1061 pfd[1].fd = kbd_fd;
1062 pfd[1].events = POLLIN;
1063 again:
1064 tcsetattr(kbd_fd, TCSANOW, &term_less);
1065 /* NB: select/poll returns whenever read will not block. Therefore:
1066 * if eof is reached, select/poll will return immediately
1067 * because read will immediately return 0 bytes.
1068 * Even if select/poll says that input is available, read CAN block
1069 * (switch fd into O_NONBLOCK'ed mode to avoid it)
1070 */
1071 rd = 1;
1072 /* Are we interested in stdin? */
1073 if (at_end()) {
1074 if (eof_error > 0) /* did NOT reach eof yet */
1075 rd = 0; /* yes, we are interested in stdin */
1076 }
1077 /* Position cursor if line input is done */
1078 if (less_gets_pos >= 0)
1079 move_cursor(max_displayed_line + 2, less_gets_pos + 1);
1080 fflush_all();
1081
1082 if (kbd_input[0] == 0) { /* if nothing is buffered */
1083 #if ENABLE_FEATURE_LESS_WINCH
1084 while (1) {
1085 int r;
1086 /* NB: SIGWINCH interrupts poll() */
1087 r = poll(pfd + rd, 2 - rd, -1);
1088 if (/*r < 0 && errno == EINTR &&*/ winch_counter)
1089 return '\\'; /* anything which has no defined function */
1090 if (r) break;
1091 }
1092 #else
1093 safe_poll(pfd + rd, 2 - rd, -1);
1094 #endif
1095 }
1096
1097 /* We have kbd_fd in O_NONBLOCK mode, read inside read_key()
1098 * would not block even if there is no input available */
1099 key64 = read_key(kbd_fd, kbd_input, /*timeout off:*/ -2);
1100 if ((int)key64 == -1) {
1101 if (errno == EAGAIN) {
1102 /* No keyboard input available. Since poll() did return,
1103 * we should have input on stdin */
1104 read_lines();
1105 buffer_fill_and_print();
1106 goto again;
1107 }
1108 /* EOF/error (ssh session got killed etc) */
1109 less_exit(0);
1110 }
1111 set_tty_cooked();
1112 return key64;
1113 }
1114
1115 /* Grab a character from input without requiring the return key.
1116 * May return KEYCODE_xxx values.
1117 * Note that this function works best with raw input. */
less_getch(int pos)1118 static int64_t less_getch(int pos)
1119 {
1120 int64_t key64;
1121 int key;
1122
1123 again:
1124 less_gets_pos = pos;
1125 key = key64 = getch_nowait();
1126 less_gets_pos = -1;
1127
1128 /* Discard Ctrl-something chars.
1129 * (checking only lower 32 bits is a size optimization:
1130 * upper 32 bits are used only by KEYCODE_CURSOR_POS)
1131 */
1132 if (key >= 0 && key < ' ' && key != 0x0d && key != 8)
1133 goto again;
1134
1135 return key64;
1136 }
1137
less_gets(int sz)1138 static char* less_gets(int sz)
1139 {
1140 int c;
1141 unsigned i = 0;
1142 char *result = xzalloc(1);
1143
1144 while (1) {
1145 c = '\0';
1146 less_gets_pos = sz + i;
1147 c = getch_nowait();
1148 if (c == 0x0d) {
1149 result[i] = '\0';
1150 less_gets_pos = -1;
1151 return result;
1152 }
1153 if (c == 0x7f)
1154 c = 8;
1155 if (c == 8 && i) {
1156 printf("\x8 \x8");
1157 i--;
1158 }
1159 if (c < ' ') /* filters out KEYCODE_xxx too (<0) */
1160 continue;
1161 if (i >= width - sz - 1)
1162 continue; /* len limit */
1163 bb_putchar(c);
1164 result[i++] = c;
1165 result = xrealloc(result, i+1);
1166 }
1167 }
1168
examine_file(void)1169 static void examine_file(void)
1170 {
1171 char *new_fname;
1172
1173 print_statusline("Examine: ");
1174 new_fname = less_gets(sizeof("Examine: ") - 1);
1175 if (!new_fname[0]) {
1176 status_print();
1177 err:
1178 free(new_fname);
1179 return;
1180 }
1181 if (access(new_fname, R_OK) != 0) {
1182 print_statusline("Cannot read this file");
1183 goto err;
1184 }
1185 free(filename);
1186 filename = new_fname;
1187 /* files start by = argv. why we assume that argv is infinitely long??
1188 files[num_files] = filename;
1189 current_file = num_files + 1;
1190 num_files++; */
1191 files[0] = filename;
1192 num_files = current_file = 1;
1193 reinitialize();
1194 }
1195
1196 /* This function changes the file currently being paged. direction can be one of the following:
1197 * -1: go back one file
1198 * 0: go to the first file
1199 * 1: go forward one file */
change_file(int direction)1200 static void change_file(int direction)
1201 {
1202 if (current_file != ((direction > 0) ? num_files : 1)) {
1203 current_file = direction ? current_file + direction : 1;
1204 free(filename);
1205 filename = xstrdup(files[current_file - 1]);
1206 reinitialize();
1207 } else {
1208 print_statusline(direction > 0 ? "No next file" : "No previous file");
1209 }
1210 }
1211
remove_current_file(void)1212 static void remove_current_file(void)
1213 {
1214 unsigned i;
1215
1216 if (num_files < 2)
1217 return;
1218
1219 if (current_file != 1) {
1220 change_file(-1);
1221 for (i = 3; i <= num_files; i++)
1222 files[i - 2] = files[i - 1];
1223 num_files--;
1224 } else {
1225 change_file(1);
1226 for (i = 2; i <= num_files; i++)
1227 files[i - 2] = files[i - 1];
1228 num_files--;
1229 current_file--;
1230 }
1231 }
1232
colon_process(void)1233 static void colon_process(void)
1234 {
1235 int keypress;
1236
1237 /* Clear the current line and print a prompt */
1238 print_statusline(" :");
1239
1240 keypress = less_getch(2);
1241 switch (keypress) {
1242 case 'd':
1243 remove_current_file();
1244 break;
1245 case 'e':
1246 examine_file();
1247 break;
1248 #if ENABLE_FEATURE_LESS_FLAGS
1249 case 'f':
1250 m_status_print();
1251 break;
1252 #endif
1253 case 'n':
1254 change_file(1);
1255 break;
1256 case 'p':
1257 change_file(-1);
1258 break;
1259 case 'q':
1260 less_exit(EXIT_SUCCESS);
1261 break;
1262 case 'x':
1263 change_file(0);
1264 break;
1265 }
1266 }
1267
1268 #if ENABLE_FEATURE_LESS_REGEXP
normalize_match_pos(int match)1269 static void normalize_match_pos(int match)
1270 {
1271 if (match >= num_matches)
1272 match = num_matches - 1;
1273 if (match < 0)
1274 match = 0;
1275 match_pos = match;
1276 }
1277
goto_match(int match)1278 static void goto_match(int match)
1279 {
1280 if (!pattern_valid)
1281 return;
1282 if (match < 0)
1283 match = 0;
1284 /* Try to find next match if eof isn't reached yet */
1285 if (match >= num_matches && eof_error > 0) {
1286 wanted_match = match; /* "I want to read until I see N'th match" */
1287 read_lines();
1288 }
1289 if (num_matches) {
1290 normalize_match_pos(match);
1291 buffer_line(match_lines[match_pos]);
1292 } else {
1293 print_statusline("No matches found");
1294 }
1295 }
1296
fill_match_lines(unsigned pos)1297 static void fill_match_lines(unsigned pos)
1298 {
1299 if (!pattern_valid)
1300 return;
1301 /* Run the regex on each line of the current file */
1302 while (pos <= max_fline) {
1303 /* If this line matches */
1304 if (regexec(&pattern, flines[pos], 0, NULL, 0) == 0
1305 /* and we didn't match it last time */
1306 && !(num_matches && match_lines[num_matches-1] == pos)
1307 ) {
1308 match_lines = xrealloc_vector(match_lines, 4, num_matches);
1309 match_lines[num_matches++] = pos;
1310 }
1311 pos++;
1312 }
1313 }
1314
regex_process(void)1315 static void regex_process(void)
1316 {
1317 char *uncomp_regex, *err;
1318
1319 /* Reset variables */
1320 free(match_lines);
1321 match_lines = NULL;
1322 match_pos = 0;
1323 num_matches = 0;
1324 if (pattern_valid) {
1325 regfree(&pattern);
1326 pattern_valid = 0;
1327 }
1328
1329 /* Get the uncompiled regular expression from the user */
1330 clear_line();
1331 bb_putchar((option_mask32 & LESS_STATE_MATCH_BACKWARDS) ? '?' : '/');
1332 uncomp_regex = less_gets(1);
1333 if (!uncomp_regex[0]) {
1334 free(uncomp_regex);
1335 buffer_print();
1336 return;
1337 }
1338
1339 /* Compile the regex and check for errors */
1340 err = regcomp_or_errmsg(&pattern, uncomp_regex,
1341 (option_mask32 & FLAG_I) ? REG_ICASE : 0);
1342 free(uncomp_regex);
1343 if (err) {
1344 print_statusline(err);
1345 free(err);
1346 return;
1347 }
1348
1349 pattern_valid = 1;
1350 match_pos = 0;
1351 fill_match_lines(0);
1352 while (match_pos < num_matches) {
1353 if ((int)match_lines[match_pos] > cur_fline)
1354 break;
1355 match_pos++;
1356 }
1357 if (option_mask32 & LESS_STATE_MATCH_BACKWARDS)
1358 match_pos--;
1359
1360 /* It's possible that no matches are found yet.
1361 * goto_match() will read input looking for match,
1362 * if needed */
1363 goto_match(match_pos);
1364 }
1365 #endif
1366
number_process(int first_digit)1367 static void number_process(int first_digit)
1368 {
1369 unsigned i;
1370 int num;
1371 int keypress;
1372 char num_input[sizeof(int)*4]; /* more than enough */
1373
1374 num_input[0] = first_digit;
1375
1376 /* Clear the current line, print a prompt, and then print the digit */
1377 clear_line();
1378 printf(":%c", first_digit);
1379
1380 /* Receive input until a letter is given */
1381 i = 1;
1382 while (i < sizeof(num_input)-1) {
1383 keypress = less_getch(i + 1);
1384 if ((unsigned)keypress > 255 || !isdigit(keypress))
1385 break;
1386 num_input[i] = keypress;
1387 bb_putchar(keypress);
1388 i++;
1389 }
1390
1391 num_input[i] = '\0';
1392 num = bb_strtou(num_input, NULL, 10);
1393 /* on format error, num == -1 */
1394 if (num < 1 || num > MAXLINES) {
1395 buffer_print();
1396 return;
1397 }
1398
1399 /* We now know the number and the letter entered, so we process them */
1400 switch (keypress) {
1401 case KEYCODE_DOWN: case 'z': case 'd': case 'e': case ' ': case '\015':
1402 buffer_down(num);
1403 break;
1404 case KEYCODE_UP: case 'b': case 'w': case 'y': case 'u':
1405 buffer_up(num);
1406 break;
1407 case 'g': case '<': case 'G': case '>':
1408 buffer_lineno(num - 1);
1409 break;
1410 case 'p': case '%':
1411 #if ENABLE_FEATURE_LESS_FLAGS
1412 update_num_lines();
1413 num = num * (num_lines > 0 ? num_lines : max_lineno) / 100;
1414 #else
1415 num = num * max_lineno / 100;
1416 #endif
1417 buffer_lineno(num);
1418 break;
1419 #if ENABLE_FEATURE_LESS_REGEXP
1420 case 'n':
1421 goto_match(match_pos + num);
1422 break;
1423 case '/':
1424 option_mask32 &= ~LESS_STATE_MATCH_BACKWARDS;
1425 regex_process();
1426 break;
1427 case '?':
1428 option_mask32 |= LESS_STATE_MATCH_BACKWARDS;
1429 regex_process();
1430 break;
1431 #endif
1432 }
1433 }
1434
1435 #if ENABLE_FEATURE_LESS_DASHCMD
flag_change(void)1436 static void flag_change(void)
1437 {
1438 int keypress;
1439
1440 clear_line();
1441 bb_putchar('-');
1442 keypress = less_getch(1);
1443
1444 switch (keypress) {
1445 case 'M':
1446 option_mask32 ^= FLAG_M;
1447 break;
1448 case 'm':
1449 option_mask32 ^= FLAG_m;
1450 break;
1451 case 'E':
1452 option_mask32 ^= FLAG_E;
1453 break;
1454 case '~':
1455 option_mask32 ^= FLAG_TILDE;
1456 break;
1457 #if ENABLE_FEATURE_LESS_TRUNCATE
1458 case 'S':
1459 option_mask32 ^= FLAG_S;
1460 buffer_fill_and_print();
1461 break;
1462 #endif
1463 #if ENABLE_FEATURE_LESS_LINENUMS
1464 case 'N':
1465 option_mask32 ^= FLAG_N;
1466 re_wrap();
1467 buffer_fill_and_print();
1468 break;
1469 #endif
1470 }
1471 }
1472
1473 #ifdef BLOAT
show_flag_status(void)1474 static void show_flag_status(void)
1475 {
1476 int keypress;
1477 int flag_val;
1478
1479 clear_line();
1480 bb_putchar('_');
1481 keypress = less_getch(1);
1482
1483 switch (keypress) {
1484 case 'M':
1485 flag_val = option_mask32 & FLAG_M;
1486 break;
1487 case 'm':
1488 flag_val = option_mask32 & FLAG_m;
1489 break;
1490 case '~':
1491 flag_val = option_mask32 & FLAG_TILDE;
1492 break;
1493 case 'N':
1494 flag_val = option_mask32 & FLAG_N;
1495 break;
1496 case 'E':
1497 flag_val = option_mask32 & FLAG_E;
1498 break;
1499 default:
1500 flag_val = 0;
1501 break;
1502 }
1503
1504 clear_line();
1505 printf(HIGHLIGHT"The status of the flag is: %u"NORMAL, flag_val != 0);
1506 }
1507 #endif
1508
1509 #endif /* ENABLE_FEATURE_LESS_DASHCMD */
1510
save_input_to_file(void)1511 static void save_input_to_file(void)
1512 {
1513 const char *msg = "";
1514 char *current_line;
1515 unsigned i;
1516 FILE *fp;
1517
1518 print_statusline("Log file: ");
1519 current_line = less_gets(sizeof("Log file: ")-1);
1520 if (current_line[0]) {
1521 fp = fopen_for_write(current_line);
1522 if (!fp) {
1523 msg = "Error opening log file";
1524 goto ret;
1525 }
1526 for (i = 0; i <= max_fline; i++)
1527 fprintf(fp, "%s\n", flines[i]);
1528 fclose(fp);
1529 msg = "Done";
1530 }
1531 ret:
1532 print_statusline(msg);
1533 free(current_line);
1534 }
1535
1536 #if ENABLE_FEATURE_LESS_MARKS
add_mark(void)1537 static void add_mark(void)
1538 {
1539 int letter;
1540
1541 print_statusline("Mark: ");
1542 letter = less_getch(sizeof("Mark: ") - 1);
1543
1544 if (isalpha(letter)) {
1545 /* If we exceed 15 marks, start overwriting previous ones */
1546 if (num_marks == 14)
1547 num_marks = 0;
1548
1549 mark_lines[num_marks][0] = letter;
1550 mark_lines[num_marks][1] = cur_fline;
1551 num_marks++;
1552 } else {
1553 print_statusline("Invalid mark letter");
1554 }
1555 }
1556
goto_mark(void)1557 static void goto_mark(void)
1558 {
1559 int letter;
1560 int i;
1561
1562 print_statusline("Go to mark: ");
1563 letter = less_getch(sizeof("Go to mark: ") - 1);
1564 clear_line();
1565
1566 if (isalpha(letter)) {
1567 for (i = 0; i <= num_marks; i++)
1568 if (letter == mark_lines[i][0]) {
1569 buffer_line(mark_lines[i][1]);
1570 break;
1571 }
1572 if (num_marks == 14 && letter != mark_lines[14][0])
1573 print_statusline("Mark not set");
1574 } else
1575 print_statusline("Invalid mark letter");
1576 }
1577 #endif
1578
1579 #if ENABLE_FEATURE_LESS_BRACKETS
opp_bracket(char bracket)1580 static char opp_bracket(char bracket)
1581 {
1582 switch (bracket) {
1583 case '{': case '[': /* '}' == '{' + 2. Same for '[' */
1584 bracket++;
1585 case '(': /* ')' == '(' + 1 */
1586 bracket++;
1587 break;
1588 case '}': case ']':
1589 bracket--;
1590 case ')':
1591 bracket--;
1592 break;
1593 };
1594 return bracket;
1595 }
1596
match_right_bracket(char bracket)1597 static void match_right_bracket(char bracket)
1598 {
1599 unsigned i = cur_fline;
1600
1601 if (i >= max_fline
1602 || strchr(flines[i], bracket) == NULL
1603 ) {
1604 print_statusline("No bracket in top line");
1605 return;
1606 }
1607
1608 bracket = opp_bracket(bracket);
1609 for (; i < max_fline; i++) {
1610 if (strchr(flines[i], bracket) != NULL) {
1611 /*
1612 * Line with matched right bracket becomes
1613 * last visible line
1614 */
1615 buffer_line(i - max_displayed_line);
1616 return;
1617 }
1618 }
1619 print_statusline("No matching bracket found");
1620 }
1621
match_left_bracket(char bracket)1622 static void match_left_bracket(char bracket)
1623 {
1624 int i = cur_fline + max_displayed_line;
1625
1626 if (i >= max_fline
1627 || strchr(flines[i], bracket) == NULL
1628 ) {
1629 print_statusline("No bracket in bottom line");
1630 return;
1631 }
1632
1633 bracket = opp_bracket(bracket);
1634 for (; i >= 0; i--) {
1635 if (strchr(flines[i], bracket) != NULL) {
1636 /*
1637 * Line with matched left bracket becomes
1638 * first visible line
1639 */
1640 buffer_line(i);
1641 return;
1642 }
1643 }
1644 print_statusline("No matching bracket found");
1645 }
1646 #endif /* FEATURE_LESS_BRACKETS */
1647
keypress_process(int keypress)1648 static void keypress_process(int keypress)
1649 {
1650 switch (keypress) {
1651 case KEYCODE_DOWN: case 'e': case 'j': case 0x0d:
1652 buffer_down(1);
1653 break;
1654 case KEYCODE_UP: case 'y': case 'k':
1655 buffer_up(1);
1656 break;
1657 case KEYCODE_PAGEDOWN: case ' ': case 'z': case 'f':
1658 buffer_down(max_displayed_line + 1);
1659 break;
1660 case KEYCODE_PAGEUP: case 'w': case 'b':
1661 buffer_up(max_displayed_line + 1);
1662 break;
1663 case 'd':
1664 buffer_down((max_displayed_line + 1) / 2);
1665 break;
1666 case 'u':
1667 buffer_up((max_displayed_line + 1) / 2);
1668 break;
1669 case KEYCODE_HOME: case 'g': case 'p': case '<': case '%':
1670 buffer_line(0);
1671 break;
1672 case KEYCODE_END: case 'G': case '>':
1673 cur_fline = MAXLINES;
1674 read_lines();
1675 buffer_line(cur_fline);
1676 break;
1677 case 'q': case 'Q':
1678 less_exit(EXIT_SUCCESS);
1679 break;
1680 #if ENABLE_FEATURE_LESS_MARKS
1681 case 'm':
1682 add_mark();
1683 buffer_print();
1684 break;
1685 case '\'':
1686 goto_mark();
1687 buffer_print();
1688 break;
1689 #endif
1690 case 'r': case 'R':
1691 /* TODO: (1) also bind ^R, ^L to this?
1692 * (2) re-measure window size?
1693 */
1694 buffer_print();
1695 break;
1696 /*case 'R':
1697 full_repaint();
1698 break;*/
1699 case 's':
1700 save_input_to_file();
1701 break;
1702 case 'E':
1703 examine_file();
1704 break;
1705 #if ENABLE_FEATURE_LESS_FLAGS
1706 case '=':
1707 m_status_print();
1708 break;
1709 #endif
1710 #if ENABLE_FEATURE_LESS_REGEXP
1711 case '/':
1712 option_mask32 &= ~LESS_STATE_MATCH_BACKWARDS;
1713 regex_process();
1714 break;
1715 case 'n':
1716 goto_match(match_pos + 1);
1717 break;
1718 case 'N':
1719 goto_match(match_pos - 1);
1720 break;
1721 case '?':
1722 option_mask32 |= LESS_STATE_MATCH_BACKWARDS;
1723 regex_process();
1724 break;
1725 #endif
1726 #if ENABLE_FEATURE_LESS_DASHCMD
1727 case '-':
1728 flag_change();
1729 buffer_print();
1730 break;
1731 #ifdef BLOAT
1732 case '_':
1733 show_flag_status();
1734 break;
1735 #endif
1736 #endif
1737 #if ENABLE_FEATURE_LESS_BRACKETS
1738 case '{': case '(': case '[':
1739 match_right_bracket(keypress);
1740 break;
1741 case '}': case ')': case ']':
1742 match_left_bracket(keypress);
1743 break;
1744 #endif
1745 case ':':
1746 colon_process();
1747 break;
1748 }
1749
1750 if (isdigit(keypress))
1751 number_process(keypress);
1752 }
1753
sig_catcher(int sig)1754 static void sig_catcher(int sig)
1755 {
1756 less_exit(- sig);
1757 }
1758
1759 #if ENABLE_FEATURE_LESS_WINCH
sigwinch_handler(int sig UNUSED_PARAM)1760 static void sigwinch_handler(int sig UNUSED_PARAM)
1761 {
1762 winch_counter++;
1763 }
1764 #endif
1765
1766 int less_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
less_main(int argc,char ** argv)1767 int less_main(int argc, char **argv)
1768 {
1769 char *tty_name;
1770 int tty_fd;
1771
1772 INIT_G();
1773
1774 /* TODO: -x: do not interpret backspace, -xx: tab also
1775 * -xxx: newline also
1776 * -w N: assume width N (-xxx -w 32: hex viewer of sorts)
1777 * -s: condense many empty lines to one
1778 * (used by some setups for manpage display)
1779 */
1780 getopt32(argv, "EMmN~I" IF_FEATURE_LESS_TRUNCATE("S") /*ignored:*/"s");
1781 argc -= optind;
1782 argv += optind;
1783 num_files = argc;
1784 files = argv;
1785
1786 /* Another popular pager, most, detects when stdout
1787 * is not a tty and turns into cat. This makes sense. */
1788 if (!isatty(STDOUT_FILENO))
1789 return bb_cat(argv);
1790
1791 if (!num_files) {
1792 if (isatty(STDIN_FILENO)) {
1793 /* Just "less"? No args and no redirection? */
1794 bb_error_msg("missing filename");
1795 bb_show_usage();
1796 }
1797 } else {
1798 filename = xstrdup(files[0]);
1799 }
1800
1801 if (option_mask32 & FLAG_TILDE)
1802 empty_line_marker = "";
1803
1804 /* Some versions of less can survive w/o controlling tty,
1805 * try to do the same. This also allows to specify an alternative
1806 * tty via "less 1<>TTY".
1807 *
1808 * We prefer not to use STDOUT_FILENO directly,
1809 * since we want to set this fd to non-blocking mode,
1810 * and not interfere with other processes which share stdout with us.
1811 */
1812 tty_name = xmalloc_ttyname(STDOUT_FILENO);
1813 if (tty_name) {
1814 tty_fd = open(tty_name, O_RDONLY);
1815 free(tty_name);
1816 if (tty_fd < 0)
1817 goto try_ctty;
1818 } else {
1819 /* Try controlling tty */
1820 try_ctty:
1821 tty_fd = open(CURRENT_TTY, O_RDONLY);
1822 if (tty_fd < 0) {
1823 /* If all else fails, less 481 uses stdout. Mimic that */
1824 tty_fd = STDOUT_FILENO;
1825 }
1826 }
1827 G.kbd_fd_orig_flags = ndelay_on(tty_fd);
1828 kbd_fd = tty_fd; /* save in a global */
1829
1830 tcgetattr(kbd_fd, &term_orig);
1831 term_less = term_orig;
1832 term_less.c_lflag &= ~(ICANON | ECHO);
1833 term_less.c_iflag &= ~(IXON | ICRNL);
1834 /*term_less.c_oflag &= ~ONLCR;*/
1835 term_less.c_cc[VMIN] = 1;
1836 term_less.c_cc[VTIME] = 0;
1837
1838 IF_FEATURE_LESS_ASK_TERMINAL(G.winsize_err =) get_terminal_width_height(kbd_fd, &width, &max_displayed_line);
1839 /* 20: two tabstops + 4 */
1840 if (width < 20 || max_displayed_line < 3)
1841 return bb_cat(argv);
1842 max_displayed_line -= 2;
1843
1844 /* We want to restore term_orig on exit */
1845 bb_signals(BB_FATAL_SIGS, sig_catcher);
1846 #if ENABLE_FEATURE_LESS_WINCH
1847 signal(SIGWINCH, sigwinch_handler);
1848 #endif
1849
1850 buffer = xmalloc((max_displayed_line+1) * sizeof(char *));
1851 reinitialize();
1852 while (1) {
1853 int64_t keypress;
1854
1855 #if ENABLE_FEATURE_LESS_WINCH
1856 while (WINCH_COUNTER) {
1857 again:
1858 winch_counter--;
1859 IF_FEATURE_LESS_ASK_TERMINAL(G.winsize_err =) get_terminal_width_height(kbd_fd, &width, &max_displayed_line);
1860 IF_FEATURE_LESS_ASK_TERMINAL(got_size:)
1861 /* 20: two tabstops + 4 */
1862 if (width < 20)
1863 width = 20;
1864 if (max_displayed_line < 3)
1865 max_displayed_line = 3;
1866 max_displayed_line -= 2;
1867 free(buffer);
1868 buffer = xmalloc((max_displayed_line+1) * sizeof(char *));
1869 /* Avoid re-wrap and/or redraw if we already know
1870 * we need to do it again. These ops are expensive */
1871 if (WINCH_COUNTER)
1872 goto again;
1873 re_wrap();
1874 if (WINCH_COUNTER)
1875 goto again;
1876 buffer_fill_and_print();
1877 /* This took some time. Loop back and check,
1878 * were there another SIGWINCH? */
1879 }
1880 keypress = less_getch(-1); /* -1: do not position cursor */
1881 # if ENABLE_FEATURE_LESS_ASK_TERMINAL
1882 if ((int32_t)keypress == KEYCODE_CURSOR_POS) {
1883 uint32_t rc = (keypress >> 32);
1884 width = (rc & 0x7fff);
1885 max_displayed_line = ((rc >> 16) & 0x7fff);
1886 goto got_size;
1887 }
1888 # endif
1889 #else
1890 keypress = less_getch(-1); /* -1: do not position cursor */
1891 #endif
1892 keypress_process(keypress);
1893 }
1894 }
1895
1896 /*
1897 Help text of less version 418 is below.
1898 If you are implementing something, keeping
1899 key and/or command line switch compatibility is a good idea:
1900
1901
1902 SUMMARY OF LESS COMMANDS
1903
1904 Commands marked with * may be preceded by a number, N.
1905 Notes in parentheses indicate the behavior if N is given.
1906 h H Display this help.
1907 q :q Q :Q ZZ Exit.
1908 ---------------------------------------------------------------------------
1909 MOVING
1910 e ^E j ^N CR * Forward one line (or N lines).
1911 y ^Y k ^K ^P * Backward one line (or N lines).
1912 f ^F ^V SPACE * Forward one window (or N lines).
1913 b ^B ESC-v * Backward one window (or N lines).
1914 z * Forward one window (and set window to N).
1915 w * Backward one window (and set window to N).
1916 ESC-SPACE * Forward one window, but don't stop at end-of-file.
1917 d ^D * Forward one half-window (and set half-window to N).
1918 u ^U * Backward one half-window (and set half-window to N).
1919 ESC-) RightArrow * Left one half screen width (or N positions).
1920 ESC-( LeftArrow * Right one half screen width (or N positions).
1921 F Forward forever; like "tail -f".
1922 r ^R ^L Repaint screen.
1923 R Repaint screen, discarding buffered input.
1924 ---------------------------------------------------
1925 Default "window" is the screen height.
1926 Default "half-window" is half of the screen height.
1927 ---------------------------------------------------------------------------
1928 SEARCHING
1929 /pattern * Search forward for (N-th) matching line.
1930 ?pattern * Search backward for (N-th) matching line.
1931 n * Repeat previous search (for N-th occurrence).
1932 N * Repeat previous search in reverse direction.
1933 ESC-n * Repeat previous search, spanning files.
1934 ESC-N * Repeat previous search, reverse dir. & spanning files.
1935 ESC-u Undo (toggle) search highlighting.
1936 ---------------------------------------------------
1937 Search patterns may be modified by one or more of:
1938 ^N or ! Search for NON-matching lines.
1939 ^E or * Search multiple files (pass thru END OF FILE).
1940 ^F or @ Start search at FIRST file (for /) or last file (for ?).
1941 ^K Highlight matches, but don't move (KEEP position).
1942 ^R Don't use REGULAR EXPRESSIONS.
1943 ---------------------------------------------------------------------------
1944 JUMPING
1945 g < ESC-< * Go to first line in file (or line N).
1946 G > ESC-> * Go to last line in file (or line N).
1947 p % * Go to beginning of file (or N percent into file).
1948 t * Go to the (N-th) next tag.
1949 T * Go to the (N-th) previous tag.
1950 { ( [ * Find close bracket } ) ].
1951 } ) ] * Find open bracket { ( [.
1952 ESC-^F <c1> <c2> * Find close bracket <c2>.
1953 ESC-^B <c1> <c2> * Find open bracket <c1>
1954 ---------------------------------------------------
1955 Each "find close bracket" command goes forward to the close bracket
1956 matching the (N-th) open bracket in the top line.
1957 Each "find open bracket" command goes backward to the open bracket
1958 matching the (N-th) close bracket in the bottom line.
1959 m<letter> Mark the current position with <letter>.
1960 '<letter> Go to a previously marked position.
1961 '' Go to the previous position.
1962 ^X^X Same as '.
1963 ---------------------------------------------------
1964 A mark is any upper-case or lower-case letter.
1965 Certain marks are predefined:
1966 ^ means beginning of the file
1967 $ means end of the file
1968 ---------------------------------------------------------------------------
1969 CHANGING FILES
1970 :e [file] Examine a new file.
1971 ^X^V Same as :e.
1972 :n * Examine the (N-th) next file from the command line.
1973 :p * Examine the (N-th) previous file from the command line.
1974 :x * Examine the first (or N-th) file from the command line.
1975 :d Delete the current file from the command line list.
1976 = ^G :f Print current file name.
1977 ---------------------------------------------------------------------------
1978 MISCELLANEOUS COMMANDS
1979 -<flag> Toggle a command line option [see OPTIONS below].
1980 --<name> Toggle a command line option, by name.
1981 _<flag> Display the setting of a command line option.
1982 __<name> Display the setting of an option, by name.
1983 +cmd Execute the less cmd each time a new file is examined.
1984 !command Execute the shell command with $SHELL.
1985 |Xcommand Pipe file between current pos & mark X to shell command.
1986 v Edit the current file with $VISUAL or $EDITOR.
1987 V Print version number of "less".
1988 ---------------------------------------------------------------------------
1989 OPTIONS
1990 Most options may be changed either on the command line,
1991 or from within less by using the - or -- command.
1992 Options may be given in one of two forms: either a single
1993 character preceded by a -, or a name preceded by --.
1994 -? ........ --help
1995 Display help (from command line).
1996 -a ........ --search-skip-screen
1997 Forward search skips current screen.
1998 -b [N] .... --buffers=[N]
1999 Number of buffers.
2000 -B ........ --auto-buffers
2001 Don't automatically allocate buffers for pipes.
2002 -c ........ --clear-screen
2003 Repaint by clearing rather than scrolling.
2004 -d ........ --dumb
2005 Dumb terminal.
2006 -D [xn.n] . --color=xn.n
2007 Set screen colors. (MS-DOS only)
2008 -e -E .... --quit-at-eof --QUIT-AT-EOF
2009 Quit at end of file.
2010 -f ........ --force
2011 Force open non-regular files.
2012 -F ........ --quit-if-one-screen
2013 Quit if entire file fits on first screen.
2014 -g ........ --hilite-search
2015 Highlight only last match for searches.
2016 -G ........ --HILITE-SEARCH
2017 Don't highlight any matches for searches.
2018 -h [N] .... --max-back-scroll=[N]
2019 Backward scroll limit.
2020 -i ........ --ignore-case
2021 Ignore case in searches that do not contain uppercase.
2022 -I ........ --IGNORE-CASE
2023 Ignore case in all searches.
2024 -j [N] .... --jump-target=[N]
2025 Screen position of target lines.
2026 -J ........ --status-column
2027 Display a status column at left edge of screen.
2028 -k [file] . --lesskey-file=[file]
2029 Use a lesskey file.
2030 -L ........ --no-lessopen
2031 Ignore the LESSOPEN environment variable.
2032 -m -M .... --long-prompt --LONG-PROMPT
2033 Set prompt style.
2034 -n -N .... --line-numbers --LINE-NUMBERS
2035 Don't use line numbers.
2036 -o [file] . --log-file=[file]
2037 Copy to log file (standard input only).
2038 -O [file] . --LOG-FILE=[file]
2039 Copy to log file (unconditionally overwrite).
2040 -p [pattern] --pattern=[pattern]
2041 Start at pattern (from command line).
2042 -P [prompt] --prompt=[prompt]
2043 Define new prompt.
2044 -q -Q .... --quiet --QUIET --silent --SILENT
2045 Quiet the terminal bell.
2046 -r -R .... --raw-control-chars --RAW-CONTROL-CHARS
2047 Output "raw" control characters.
2048 -s ........ --squeeze-blank-lines
2049 Squeeze multiple blank lines.
2050 -S ........ --chop-long-lines
2051 Chop long lines.
2052 -t [tag] .. --tag=[tag]
2053 Find a tag.
2054 -T [tagsfile] --tag-file=[tagsfile]
2055 Use an alternate tags file.
2056 -u -U .... --underline-special --UNDERLINE-SPECIAL
2057 Change handling of backspaces.
2058 -V ........ --version
2059 Display the version number of "less".
2060 -w ........ --hilite-unread
2061 Highlight first new line after forward-screen.
2062 -W ........ --HILITE-UNREAD
2063 Highlight first new line after any forward movement.
2064 -x [N[,...]] --tabs=[N[,...]]
2065 Set tab stops.
2066 -X ........ --no-init
2067 Don't use termcap init/deinit strings.
2068 --no-keypad
2069 Don't use termcap keypad init/deinit strings.
2070 -y [N] .... --max-forw-scroll=[N]
2071 Forward scroll limit.
2072 -z [N] .... --window=[N]
2073 Set size of window.
2074 -" [c[c]] . --quotes=[c[c]]
2075 Set shell quote characters.
2076 -~ ........ --tilde
2077 Don't display tildes after end of file.
2078 -# [N] .... --shift=[N]
2079 Horizontal scroll amount (0 = one half screen width)
2080
2081 ---------------------------------------------------------------------------
2082 LINE EDITING
2083 These keys can be used to edit text being entered
2084 on the "command line" at the bottom of the screen.
2085 RightArrow ESC-l Move cursor right one character.
2086 LeftArrow ESC-h Move cursor left one character.
2087 CNTL-RightArrow ESC-RightArrow ESC-w Move cursor right one word.
2088 CNTL-LeftArrow ESC-LeftArrow ESC-b Move cursor left one word.
2089 HOME ESC-0 Move cursor to start of line.
2090 END ESC-$ Move cursor to end of line.
2091 BACKSPACE Delete char to left of cursor.
2092 DELETE ESC-x Delete char under cursor.
2093 CNTL-BACKSPACE ESC-BACKSPACE Delete word to left of cursor.
2094 CNTL-DELETE ESC-DELETE ESC-X Delete word under cursor.
2095 CNTL-U ESC (MS-DOS only) Delete entire line.
2096 UpArrow ESC-k Retrieve previous command line.
2097 DownArrow ESC-j Retrieve next command line.
2098 TAB Complete filename & cycle.
2099 SHIFT-TAB ESC-TAB Complete filename & reverse cycle.
2100 CNTL-L Complete filename, list all.
2101 */
2102