1 /* vi: set sw=4 ts=4: */
3 * Mini less implementation for busybox
5 * Copyright (C) 2005 by Rob Sullivan <cogito.ergo.cogito@gmail.com>
7 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
12 * - Add more regular expression support - search modifiers, certain matches, etc.
13 * - Add more complex bracket searching - currently, nested brackets are
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.
20 * - the inp file pointer is used so that keyboard input works after
21 * redirected input has been read from stdin
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'.
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
36 //config:config FEATURE_LESS_BRACKETS
37 //config: bool "Enable bracket searching"
39 //config: depends on LESS
41 //config: This option adds the capability to search for matching left and right
42 //config: brackets, facilitating programming.
44 //config:config FEATURE_LESS_FLAGS
45 //config: bool "Enable -m/-M"
47 //config: depends on LESS
49 //config: The -M/-m flag enables a more sophisticated status line.
51 //config:config FEATURE_LESS_MARKS
52 //config: bool "Enable marks"
54 //config: depends on LESS
56 //config: Marks enable positions in a file to be stored for easy reference.
58 //config:config FEATURE_LESS_REGEXP
59 //config: bool "Enable regular expressions"
61 //config: depends on LESS
63 //config: Enable regular expressions, allowing complex file searches.
65 //config:config FEATURE_LESS_WINCH
66 //config: bool "Enable automatic resizing on window size changes"
68 //config: depends on LESS
70 //config: Makes less track window size changes.
72 //config:config FEATURE_LESS_ASK_TERMINAL
73 //config: bool "Use 'tell me cursor position' ESC sequence to measure window"
75 //config: depends on FEATURE_LESS_WINCH
77 //config: Makes less track window size changes.
78 //config: If terminal size can't be retrieved and $LINES/$COLUMNS are not set,
79 //config: this option makes less perform a last-ditch effort to find it:
80 //config: position cursor to 999,999 and ask terminal to report real
81 //config: cursor position using "ESC [ 6 n" escape sequence, then read stdin.
83 //config: This is not clean but helps a lot on serial lines and such.
85 //config:config FEATURE_LESS_DASHCMD
86 //config: bool "Enable flag changes ('-' command)"
88 //config: depends on LESS
90 //config: This enables the ability to change command-line flags within
91 //config: less itself ('-' keyboard command).
93 //config:config FEATURE_LESS_LINENUMS
94 //config: bool "Enable dynamic switching of line numbers"
96 //config: depends on FEATURE_LESS_DASHCMD
98 //config: Enables "-N" command.
100 //usage:#define less_trivial_usage
101 //usage: "[-E" IF_FEATURE_LESS_FLAGS("Mm") "Nh~I?] [FILE]..."
102 //usage:#define less_full_usage "\n\n"
103 //usage: "View FILE (or stdin) one screenful at a time\n"
104 //usage: "\n -E Quit once the end of a file is reached"
105 //usage: IF_FEATURE_LESS_FLAGS(
106 //usage: "\n -M,-m Display status line with line numbers"
107 //usage: "\n and percentage through the file"
109 //usage: "\n -N Prefix line number to each line"
110 //usage: "\n -I Ignore case in all searches"
111 //usage: "\n -~ Suppress ~s displayed past EOF"
113 #include <sched.h> /* sched_yield() */
116 #if ENABLE_FEATURE_LESS_REGEXP
122 /* The escape codes for highlighted and normal text */
123 #define HIGHLIGHT ESC"[7m"
124 #define NORMAL ESC"[0m"
125 /* The escape code to home and clear to the end of screen */
126 #define CLEAR ESC"[H\033[J"
127 /* The escape code to clear to the end of line */
128 #define CLEAR_2_EOL ESC"[K"
131 /* Absolute max of lines eaten */
132 MAXLINES
= CONFIG_FEATURE_LESS_MAXLINES
,
133 /* This many "after the end" lines we will show (at max) */
137 /* Command line options */
145 FLAG_S
= (1 << 6) * ENABLE_FEATURE_LESS_DASHCMD
,
146 /* hijack command line options variable for internal state vars */
147 LESS_STATE_MATCH_BACKWARDS
= 1 << 15,
150 #if !ENABLE_FEATURE_LESS_REGEXP
151 enum { pattern_valid
= 0 };
155 int cur_fline
; /* signed */
156 int kbd_fd
; /* fd to get input from */
158 /* last position in last line, taking into account tabs */
159 size_t last_line_pos
;
161 unsigned max_lineno
; /* this one tracks linewrap */
162 unsigned max_displayed_line
;
164 #if ENABLE_FEATURE_LESS_WINCH
165 unsigned winch_counter
;
167 ssize_t eof_error
; /* eof if 0, error if < 0 */
169 ssize_t readeof
; /* must be signed */
172 const char *empty_line_marker
;
174 unsigned current_file
;
177 #if ENABLE_FEATURE_LESS_MARKS
179 unsigned mark_lines
[15][2];
181 #if ENABLE_FEATURE_LESS_REGEXP
182 unsigned *match_lines
;
183 int match_pos
; /* signed! */
184 int wanted_match
; /* signed! */
187 smallint pattern_valid
;
189 #if ENABLE_FEATURE_LESS_ASK_TERMINAL
190 smallint winsize_err
;
193 struct termios term_orig
, term_less
;
194 char kbd_input
[KEYCODE_BUFFER_SIZE
];
196 #define G (*ptr_to_globals)
197 #define cur_fline (G.cur_fline )
198 #define kbd_fd (G.kbd_fd )
199 #define less_gets_pos (G.less_gets_pos )
200 #define last_line_pos (G.last_line_pos )
201 #define max_fline (G.max_fline )
202 #define max_lineno (G.max_lineno )
203 #define max_displayed_line (G.max_displayed_line)
204 #define width (G.width )
205 #define winch_counter (G.winch_counter )
206 /* This one is 100% not cached by compiler on read access */
207 #define WINCH_COUNTER (*(volatile unsigned *)&winch_counter)
208 #define eof_error (G.eof_error )
209 #define readpos (G.readpos )
210 #define readeof (G.readeof )
211 #define buffer (G.buffer )
212 #define flines (G.flines )
213 #define empty_line_marker (G.empty_line_marker )
214 #define num_files (G.num_files )
215 #define current_file (G.current_file )
216 #define filename (G.filename )
217 #define files (G.files )
218 #define num_marks (G.num_marks )
219 #define mark_lines (G.mark_lines )
220 #if ENABLE_FEATURE_LESS_REGEXP
221 #define match_lines (G.match_lines )
222 #define match_pos (G.match_pos )
223 #define num_matches (G.num_matches )
224 #define wanted_match (G.wanted_match )
225 #define pattern (G.pattern )
226 #define pattern_valid (G.pattern_valid )
228 #define terminated (G.terminated )
229 #define term_orig (G.term_orig )
230 #define term_less (G.term_less )
231 #define kbd_input (G.kbd_input )
232 #define INIT_G() do { \
233 SET_PTR_TO_GLOBALS(xzalloc(sizeof(G))); \
234 less_gets_pos = -1; \
235 empty_line_marker = "~"; \
240 IF_FEATURE_LESS_REGEXP(wanted_match = -1;) \
243 /* flines[] are lines read from stdin, each in malloc'ed buffer.
244 * Line numbers are stored as uint32_t prepended to each line.
245 * Pointer is adjusted so that flines[i] points directly past
246 * line number. Accesor: */
247 #define MEMPTR(p) ((char*)(p) - 4)
248 #define LINENO(p) (*(uint32_t*)((p) - 4))
251 /* Reset terminal input to normal */
252 static void set_tty_cooked(void)
255 tcsetattr(kbd_fd
, TCSANOW
, &term_orig
);
258 /* Move the cursor to a position (x,y), where (0,0) is the
259 top-left corner of the console */
260 static void move_cursor(int line
, int row
)
262 printf(ESC
"[%u;%uH", line
, row
);
265 static void clear_line(void)
267 printf(ESC
"[%u;0H" CLEAR_2_EOL
, max_displayed_line
+ 2);
270 static void print_hilite(const char *str
)
272 printf(HIGHLIGHT
"%s"NORMAL
, str
);
275 static void print_statusline(const char *str
)
278 printf(HIGHLIGHT
"%.*s"NORMAL
, width
- 1, str
);
281 /* Exit the program gracefully */
282 static void less_exit(int code
)
287 kill_myself_with_sig(- code
); /* does not return */
291 #if (ENABLE_FEATURE_LESS_DASHCMD && ENABLE_FEATURE_LESS_LINENUMS) \
292 || ENABLE_FEATURE_LESS_WINCH
293 static void re_wrap(void)
299 int new_cur_fline
= 0;
302 const char **old_flines
= flines
;
304 char **new_flines
= NULL
;
307 if (option_mask32
& FLAG_N
)
320 if (*d
== '\t') /* tab */
324 if (new_line_pos
>= w
) {
326 /* new line is full, create next one */
329 sz
= (d
- linebuf
) + 1; /* + 1: NUL */
330 d
= ((char*)xmalloc(sz
+ 4)) + 4;
332 memcpy(d
, linebuf
, sz
);
333 new_flines
= xrealloc_vector(new_flines
, 8, dst_idx
);
334 new_flines
[dst_idx
] = d
;
336 if (new_line_pos
< w
) {
337 /* if we came here thru "goto next_new" */
338 if (src_idx
> max_fline
)
347 /* *d == NUL: old line ended, go to next old one */
348 free(MEMPTR(old_flines
[src_idx
]));
349 /* btw, convert cur_fline... */
350 if (cur_fline
== src_idx
)
351 new_cur_fline
= dst_idx
;
353 /* no more lines? finish last new line (and exit the loop) */
354 if (src_idx
> max_fline
)
356 s
= old_flines
[src_idx
];
357 if (lineno
!= LINENO(s
)) {
358 /* this is not a continuation line!
359 * create next _new_ line too */
365 flines
= (const char **)new_flines
;
367 max_fline
= dst_idx
- 1;
368 last_line_pos
= new_line_pos
;
369 cur_fline
= new_cur_fline
;
370 /* max_lineno is screen-size independent */
371 #if ENABLE_FEATURE_LESS_REGEXP
377 #if ENABLE_FEATURE_LESS_REGEXP
378 static void fill_match_lines(unsigned pos
);
380 #define fill_match_lines(pos) ((void)0)
383 /* Devilishly complex routine.
385 * Has to deal with EOF and EPIPE on input,
386 * with line wrapping, with last line not ending in '\n'
387 * (possibly not ending YET!), with backspace and tabs.
388 * It reads input again if last time we got an EOF (thus supporting
389 * growing files) or EPIPE (watching output of slow process like make).
392 * flines[] - array of lines already read. Linewrap may cause
393 * one source file line to occupy several flines[n].
394 * flines[max_fline] - last line, possibly incomplete.
395 * terminated - 1 if flines[max_fline] is 'terminated'
396 * (if there was '\n' [which isn't stored itself, we just remember
398 * max_lineno - last line's number, this one doesn't increment
399 * on line wrap, only on "real" new lines.
400 * readbuf[0..readeof-1] - small preliminary buffer.
401 * readbuf[readpos] - next character to add to current line.
402 * last_line_pos - screen line position of next char to be read
403 * (takes into account tabs and backspaces)
404 * eof_error - < 0 error, == 0 EOF, > 0 not EOF/error
406 static void read_lines(void)
408 #define readbuf bb_common_bufsiz1
409 char *current_line
, *p
;
411 char last_terminated
= terminated
;
412 #if ENABLE_FEATURE_LESS_REGEXP
413 unsigned old_max_fline
= max_fline
;
414 time_t last_time
= 0;
415 unsigned seconds_p1
= 3; /* seconds_to_loop + 1 */
418 if (option_mask32
& FLAG_N
)
421 IF_FEATURE_LESS_REGEXP(again0
:)
423 p
= current_line
= ((char*)xmalloc(w
+ 4)) + 4;
424 max_fline
+= last_terminated
;
425 if (!last_terminated
) {
426 const char *cp
= flines
[max_fline
];
428 p
+= strlen(current_line
);
429 free(MEMPTR(flines
[max_fline
]));
430 /* last_line_pos is still valid from previous read_lines() */
435 while (1) { /* read lines until we reach cur_fline or wanted_match */
438 while (1) { /* read chars until we have a line */
440 /* if no unprocessed chars left, eat more */
441 if (readpos
>= readeof
) {
443 eof_error
= safe_read(STDIN_FILENO
, readbuf
, sizeof(readbuf
));
450 c
= readbuf
[readpos
];
451 /* backspace? [needed for manpages] */
452 /* <tab><bs> is (a) insane and */
453 /* (b) harder to do correctly, so we refuse to do it */
454 if (c
== '\x8' && last_line_pos
&& p
[-1] != '\t') {
455 readpos
++; /* eat it */
457 /* was buggy (p could end up <= current_line)... */
462 size_t new_last_line_pos
= last_line_pos
+ 1;
464 new_last_line_pos
+= 7;
465 new_last_line_pos
&= (~7);
467 if ((int)new_last_line_pos
>= w
)
469 last_line_pos
= new_last_line_pos
;
471 /* ok, we will eat this char */
478 /* NUL is substituted by '\n'! */
479 if (c
== '\0') c
= '\n';
482 } /* end of "read chars until we have a line" loop */
483 /* Corner case: linewrap with only "" wrapping to next line */
484 /* Looks ugly on screen, so we do not store this empty line */
485 if (!last_terminated
&& !current_line
[0]) {
491 last_terminated
= terminated
;
492 flines
= xrealloc_vector(flines
, 8, max_fline
);
494 flines
[max_fline
] = (char*)xrealloc(MEMPTR(current_line
), strlen(current_line
) + 1 + 4) + 4;
495 LINENO(flines
[max_fline
]) = max_lineno
;
499 if (max_fline
>= MAXLINES
) {
500 eof_error
= 0; /* Pretend we saw EOF */
503 if (!(option_mask32
& FLAG_S
)
504 ? (max_fline
> cur_fline
+ max_displayed_line
)
505 : (max_fline
>= cur_fline
506 && max_lineno
> LINENO(flines
[cur_fline
]) + max_displayed_line
)
508 #if !ENABLE_FEATURE_LESS_REGEXP
511 if (wanted_match
>= num_matches
) { /* goto_match called us */
512 fill_match_lines(old_max_fline
);
513 old_max_fline
= max_fline
;
515 if (wanted_match
< num_matches
)
519 if (eof_error
<= 0) {
521 if (errno
== EAGAIN
) {
522 /* not yet eof or error, reset flag (or else
523 * we will hog CPU - select() will return
527 print_statusline(bb_msg_read_error
);
530 #if !ENABLE_FEATURE_LESS_REGEXP
533 if (wanted_match
< num_matches
) {
535 } else { /* goto_match called us */
536 time_t t
= time(NULL
);
537 if (t
!= last_time
) {
539 if (--seconds_p1
== 0)
543 goto again0
; /* go loop again (max 2 seconds) */
548 current_line
= ((char*)xmalloc(w
+ 4)) + 4;
551 } /* end of "read lines until we reach cur_fline" loop */
552 fill_match_lines(old_max_fline
);
553 #if ENABLE_FEATURE_LESS_REGEXP
554 /* prevent us from being stuck in search for a match */
560 #if ENABLE_FEATURE_LESS_FLAGS
561 /* Interestingly, writing calc_percent as a function saves around 32 bytes
563 static int calc_percent(void)
565 unsigned p
= (100 * (cur_fline
+max_displayed_line
+1) + max_fline
/2) / (max_fline
+1);
566 return p
<= 100 ? p
: 100;
569 /* Print a status line if -M was specified */
570 static void m_status_print(void)
574 if (less_gets_pos
>= 0) /* don't touch statusline while input is done! */
578 printf(HIGHLIGHT
"%s", filename
);
580 printf(" (file %i of %i)", current_file
, num_files
);
581 printf(" lines %i-%i/%i ",
582 cur_fline
+ 1, cur_fline
+ max_displayed_line
+ 1,
584 if (cur_fline
>= (int)(max_fline
- max_displayed_line
)) {
585 printf("(END)"NORMAL
);
586 if (num_files
> 1 && current_file
!= num_files
)
587 printf(HIGHLIGHT
" - next: %s"NORMAL
, files
[current_file
]);
590 percentage
= calc_percent();
591 printf("%i%%"NORMAL
, percentage
);
595 /* Print the status line */
596 static void status_print(void)
600 if (less_gets_pos
>= 0) /* don't touch statusline while input is done! */
603 /* Change the status if flags have been set */
604 #if ENABLE_FEATURE_LESS_FLAGS
605 if (option_mask32
& (FLAG_M
|FLAG_m
)) {
613 if (cur_fline
&& cur_fline
< (int)(max_fline
- max_displayed_line
)) {
621 printf(HIGHLIGHT
"%s (file %i of %i)"NORMAL
,
622 p
, current_file
, num_files
);
628 static void cap_cur_fline(int nlines
)
633 if (cur_fline
+ max_displayed_line
> max_fline
+ TILDES
) {
637 diff
= max_fline
- (cur_fline
+ max_displayed_line
) + TILDES
;
638 /* As the number of lines requested was too large, we just move
639 * to the end of the file */
645 static const char controls
[] ALIGN1
=
646 /* NUL: never encountered; TAB: not converted */
647 /**/"\x01\x02\x03\x04\x05\x06\x07\x08" "\x0a\x0b\x0c\x0d\x0e\x0f"
648 "\x10\x11\x12\x13\x14\x15\x16\x17\x18\x19\x1a\x1b\x1c\x1d\x1e\x1f"
649 "\x7f\x9b"; /* DEL and infamous Meta-ESC :( */
650 static const char ctrlconv
[] ALIGN1
=
651 /* why 40 instead of 4a below? - it is a replacement for '\n'.
652 * '\n' is a former NUL - we subst it with @, not J */
653 "\x40\x41\x42\x43\x44\x45\x46\x47\x48\x49\x40\x4b\x4c\x4d\x4e\x4f"
654 "\x50\x51\x52\x53\x54\x55\x56\x57\x58\x59\x5a\x5b\x5c\x5d\x5e\x5f";
656 static void lineno_str(char *nbuf9
, const char *line
)
659 if (option_mask32
& FLAG_N
) {
663 if (line
== empty_line_marker
) {
664 memset(nbuf9
, ' ', 8);
668 /* Width of 7 preserves tab spacing in the text */
670 n
= LINENO(line
) + 1;
675 sprintf(nbuf9
, fmt
, n
);
680 #if ENABLE_FEATURE_LESS_REGEXP
681 static void print_found(const char *line
)
686 regmatch_t match_structs
;
690 const char *str
= line
;
695 n
= strcspn(str
, controls
);
702 n
= strspn(str
, controls
);
709 /* buf[] holds quarantined version of str */
711 /* Each part of the line that matches has the HIGHLIGHT
712 * and NORMAL escape sequences placed around it.
713 * NB: we regex against line, but insert text
714 * from quarantined copy (buf[]) */
720 while (match_status
== 0) {
721 char *new = xasprintf("%s%.*s"HIGHLIGHT
"%.*s"NORMAL
,
722 growline
? growline
: "",
723 (int)match_structs
.rm_so
, str
,
724 (int)(match_structs
.rm_eo
- match_structs
.rm_so
),
725 str
+ match_structs
.rm_so
);
728 str
+= match_structs
.rm_eo
;
729 line
+= match_structs
.rm_eo
;
732 /* Most of the time doesn't find the regex, optimize for that */
733 match_status
= regexec(&pattern
, line
, 1, &match_structs
, eflags
);
734 /* if even "" matches, treat it as "not a match" */
735 if (match_structs
.rm_so
>= match_structs
.rm_eo
)
739 lineno_str(nbuf9
, line
);
741 printf(CLEAR_2_EOL
"%s%s\n", nbuf9
, str
);
744 printf(CLEAR_2_EOL
"%s%s%s\n", nbuf9
, growline
, str
);
748 void print_found(const char *line
);
751 static void print_ascii(const char *str
)
758 lineno_str(nbuf9
, str
);
759 printf(CLEAR_2_EOL
"%s", nbuf9
);
762 n
= strcspn(str
, controls
);
765 printf("%.*s", (int) n
, str
);
768 n
= strspn(str
, controls
);
773 else if (*str
== (char)0x9b)
774 /* VT100's CSI, aka Meta-ESC. Who's inventor? */
775 /* I want to know who committed this sin */
778 *p
++ = ctrlconv
[(unsigned char)*str
];
787 /* Print the buffer */
788 static void buffer_print(void)
793 for (i
= 0; i
<= max_displayed_line
; i
++)
795 print_found(buffer
[i
]);
797 print_ascii(buffer
[i
]);
801 static void buffer_fill_and_print(void)
804 #if ENABLE_FEATURE_LESS_DASHCMD
805 int fpos
= cur_fline
;
807 if (option_mask32
& FLAG_S
) {
808 /* Go back to the beginning of this line */
809 while (fpos
&& LINENO(flines
[fpos
]) == LINENO(flines
[fpos
-1]))
814 while (i
<= max_displayed_line
&& fpos
<= max_fline
) {
815 int lineno
= LINENO(flines
[fpos
]);
816 buffer
[i
] = flines
[fpos
];
820 } while ((fpos
<= max_fline
)
821 && (option_mask32
& FLAG_S
)
822 && lineno
== LINENO(flines
[fpos
])
826 for (i
= 0; i
<= max_displayed_line
&& cur_fline
+ i
<= max_fline
; i
++) {
827 buffer
[i
] = flines
[cur_fline
+ i
];
830 for (; i
<= max_displayed_line
; i
++) {
831 buffer
[i
] = empty_line_marker
;
836 /* Move the buffer up and down in the file in order to scroll */
837 static void buffer_down(int nlines
)
841 cap_cur_fline(nlines
);
842 buffer_fill_and_print();
845 static void buffer_up(int nlines
)
848 if (cur_fline
< 0) cur_fline
= 0;
850 buffer_fill_and_print();
853 static void buffer_line(int linenum
)
859 if (linenum
+ max_displayed_line
> max_fline
)
860 linenum
= max_fline
- max_displayed_line
+ TILDES
;
864 buffer_fill_and_print();
867 static void open_file_and_read_lines(void)
870 xmove_fd(xopen(filename
, O_RDONLY
), STDIN_FILENO
);
872 /* "less" with no arguments in argv[] */
873 /* For status line only */
874 filename
= xstrdup(bb_msg_standard_input
);
883 /* Reinitialize everything for a new file - free the memory and start over */
884 static void reinitialize(void)
889 for (i
= 0; i
<= max_fline
; i
++)
890 free(MEMPTR(flines
[i
]));
898 open_file_and_read_lines();
899 #if ENABLE_FEATURE_LESS_ASK_TERMINAL
901 printf("\033[999;999H" "\033[6n");
903 buffer_fill_and_print();
906 static int64_t getch_nowait(void)
910 struct pollfd pfd
[2];
912 pfd
[0].fd
= STDIN_FILENO
;
913 pfd
[0].events
= POLLIN
;
915 pfd
[1].events
= POLLIN
;
917 tcsetattr(kbd_fd
, TCSANOW
, &term_less
);
918 /* NB: select/poll returns whenever read will not block. Therefore:
919 * if eof is reached, select/poll will return immediately
920 * because read will immediately return 0 bytes.
921 * Even if select/poll says that input is available, read CAN block
922 * (switch fd into O_NONBLOCK'ed mode to avoid it)
925 /* Are we interested in stdin? */
926 //TODO: reuse code for determining this
927 if (!(option_mask32
& FLAG_S
)
928 ? !(max_fline
> cur_fline
+ max_displayed_line
)
929 : !(max_fline
>= cur_fline
930 && max_lineno
> LINENO(flines
[cur_fline
]) + max_displayed_line
)
932 if (eof_error
> 0) /* did NOT reach eof yet */
933 rd
= 0; /* yes, we are interested in stdin */
935 /* Position cursor if line input is done */
936 if (less_gets_pos
>= 0)
937 move_cursor(max_displayed_line
+ 2, less_gets_pos
+ 1);
940 if (kbd_input
[0] == 0) { /* if nothing is buffered */
941 #if ENABLE_FEATURE_LESS_WINCH
944 /* NB: SIGWINCH interrupts poll() */
945 r
= poll(pfd
+ rd
, 2 - rd
, -1);
946 if (/*r < 0 && errno == EINTR &&*/ winch_counter
)
947 return '\\'; /* anything which has no defined function */
951 safe_poll(pfd
+ rd
, 2 - rd
, -1);
955 /* We have kbd_fd in O_NONBLOCK mode, read inside read_key()
956 * would not block even if there is no input available */
957 key64
= read_key(kbd_fd
, kbd_input
, /*timeout off:*/ -2);
958 if ((int)key64
== -1) {
959 if (errno
== EAGAIN
) {
960 /* No keyboard input available. Since poll() did return,
961 * we should have input on stdin */
963 buffer_fill_and_print();
966 /* EOF/error (ssh session got killed etc) */
973 /* Grab a character from input without requiring the return key.
974 * May return KEYCODE_xxx values.
975 * Note that this function works best with raw input. */
976 static int64_t less_getch(int pos
)
983 key
= key64
= getch_nowait();
986 /* Discard Ctrl-something chars.
987 * (checking only lower 32 bits is a size optimization:
988 * upper 32 bits are used only by KEYCODE_CURSOR_POS)
990 if (key
>= 0 && key
< ' ' && key
!= 0x0d && key
!= 8)
996 static char* less_gets(int sz
)
1000 char *result
= xzalloc(1);
1004 less_gets_pos
= sz
+ i
;
1017 if (c
< ' ') /* filters out KEYCODE_xxx too (<0) */
1019 if (i
>= width
- sz
- 1)
1020 continue; /* len limit */
1023 result
= xrealloc(result
, i
+1);
1027 static void examine_file(void)
1031 print_statusline("Examine: ");
1032 new_fname
= less_gets(sizeof("Examine: ") - 1);
1033 if (!new_fname
[0]) {
1039 if (access(new_fname
, R_OK
) != 0) {
1040 print_statusline("Cannot read this file");
1044 filename
= new_fname
;
1045 /* files start by = argv. why we assume that argv is infinitely long??
1046 files[num_files] = filename;
1047 current_file = num_files + 1;
1049 files
[0] = filename
;
1050 num_files
= current_file
= 1;
1054 /* This function changes the file currently being paged. direction can be one of the following:
1055 * -1: go back one file
1056 * 0: go to the first file
1057 * 1: go forward one file */
1058 static void change_file(int direction
)
1060 if (current_file
!= ((direction
> 0) ? num_files
: 1)) {
1061 current_file
= direction
? current_file
+ direction
: 1;
1063 filename
= xstrdup(files
[current_file
- 1]);
1066 print_statusline(direction
> 0 ? "No next file" : "No previous file");
1070 static void remove_current_file(void)
1077 if (current_file
!= 1) {
1079 for (i
= 3; i
<= num_files
; i
++)
1080 files
[i
- 2] = files
[i
- 1];
1084 for (i
= 2; i
<= num_files
; i
++)
1085 files
[i
- 2] = files
[i
- 1];
1091 static void colon_process(void)
1095 /* Clear the current line and print a prompt */
1096 print_statusline(" :");
1098 keypress
= less_getch(2);
1101 remove_current_file();
1106 #if ENABLE_FEATURE_LESS_FLAGS
1118 less_exit(EXIT_SUCCESS
);
1126 #if ENABLE_FEATURE_LESS_REGEXP
1127 static void normalize_match_pos(int match
)
1129 if (match
>= num_matches
)
1130 match
= num_matches
- 1;
1136 static void goto_match(int match
)
1142 /* Try to find next match if eof isn't reached yet */
1143 if (match
>= num_matches
&& eof_error
> 0) {
1144 wanted_match
= match
; /* "I want to read until I see N'th match" */
1148 normalize_match_pos(match
);
1149 buffer_line(match_lines
[match_pos
]);
1151 print_statusline("No matches found");
1155 static void fill_match_lines(unsigned pos
)
1159 /* Run the regex on each line of the current file */
1160 while (pos
<= max_fline
) {
1161 /* If this line matches */
1162 if (regexec(&pattern
, flines
[pos
], 0, NULL
, 0) == 0
1163 /* and we didn't match it last time */
1164 && !(num_matches
&& match_lines
[num_matches
-1] == pos
)
1166 match_lines
= xrealloc_vector(match_lines
, 4, num_matches
);
1167 match_lines
[num_matches
++] = pos
;
1173 static void regex_process(void)
1175 char *uncomp_regex
, *err
;
1177 /* Reset variables */
1182 if (pattern_valid
) {
1187 /* Get the uncompiled regular expression from the user */
1189 bb_putchar((option_mask32
& LESS_STATE_MATCH_BACKWARDS
) ? '?' : '/');
1190 uncomp_regex
= less_gets(1);
1191 if (!uncomp_regex
[0]) {
1197 /* Compile the regex and check for errors */
1198 err
= regcomp_or_errmsg(&pattern
, uncomp_regex
,
1199 (option_mask32
& FLAG_I
) ? REG_ICASE
: 0);
1202 print_statusline(err
);
1209 fill_match_lines(0);
1210 while (match_pos
< num_matches
) {
1211 if ((int)match_lines
[match_pos
] > cur_fline
)
1215 if (option_mask32
& LESS_STATE_MATCH_BACKWARDS
)
1218 /* It's possible that no matches are found yet.
1219 * goto_match() will read input looking for match,
1221 goto_match(match_pos
);
1225 static void number_process(int first_digit
)
1230 char num_input
[sizeof(int)*4]; /* more than enough */
1232 num_input
[0] = first_digit
;
1234 /* Clear the current line, print a prompt, and then print the digit */
1236 printf(":%c", first_digit
);
1238 /* Receive input until a letter is given */
1240 while (i
< sizeof(num_input
)-1) {
1241 keypress
= less_getch(i
+ 1);
1242 if ((unsigned)keypress
> 255 || !isdigit(num_input
[i
]))
1244 num_input
[i
] = keypress
;
1245 bb_putchar(keypress
);
1249 num_input
[i
] = '\0';
1250 num
= bb_strtou(num_input
, NULL
, 10);
1251 /* on format error, num == -1 */
1252 if (num
< 1 || num
> MAXLINES
) {
1257 /* We now know the number and the letter entered, so we process them */
1259 case KEYCODE_DOWN
: case 'z': case 'd': case 'e': case ' ': case '\015':
1262 case KEYCODE_UP
: case 'b': case 'w': case 'y': case 'u':
1265 case 'g': case '<': case 'G': case '>':
1266 cur_fline
= num
+ max_displayed_line
;
1268 buffer_line(num
- 1);
1271 num
= num
* (max_fline
/ 100); /* + max_fline / 2; */
1272 cur_fline
= num
+ max_displayed_line
;
1276 #if ENABLE_FEATURE_LESS_REGEXP
1278 goto_match(match_pos
+ num
);
1281 option_mask32
&= ~LESS_STATE_MATCH_BACKWARDS
;
1285 option_mask32
|= LESS_STATE_MATCH_BACKWARDS
;
1292 #if ENABLE_FEATURE_LESS_DASHCMD
1293 static void flag_change(void)
1299 keypress
= less_getch(1);
1303 option_mask32
^= FLAG_M
;
1306 option_mask32
^= FLAG_m
;
1309 option_mask32
^= FLAG_E
;
1312 option_mask32
^= FLAG_TILDE
;
1315 option_mask32
^= FLAG_S
;
1316 buffer_fill_and_print();
1318 #if ENABLE_FEATURE_LESS_LINENUMS
1320 option_mask32
^= FLAG_N
;
1322 buffer_fill_and_print();
1329 static void show_flag_status(void)
1336 keypress
= less_getch(1);
1340 flag_val
= option_mask32
& FLAG_M
;
1343 flag_val
= option_mask32
& FLAG_m
;
1346 flag_val
= option_mask32
& FLAG_TILDE
;
1349 flag_val
= option_mask32
& FLAG_N
;
1352 flag_val
= option_mask32
& FLAG_E
;
1360 printf(HIGHLIGHT
"The status of the flag is: %u"NORMAL
, flag_val
!= 0);
1364 #endif /* ENABLE_FEATURE_LESS_DASHCMD */
1366 static void save_input_to_file(void)
1368 const char *msg
= "";
1373 print_statusline("Log file: ");
1374 current_line
= less_gets(sizeof("Log file: ")-1);
1375 if (current_line
[0]) {
1376 fp
= fopen_for_write(current_line
);
1378 msg
= "Error opening log file";
1381 for (i
= 0; i
<= max_fline
; i
++)
1382 fprintf(fp
, "%s\n", flines
[i
]);
1387 print_statusline(msg
);
1391 #if ENABLE_FEATURE_LESS_MARKS
1392 static void add_mark(void)
1396 print_statusline("Mark: ");
1397 letter
= less_getch(sizeof("Mark: ") - 1);
1399 if (isalpha(letter
)) {
1400 /* If we exceed 15 marks, start overwriting previous ones */
1401 if (num_marks
== 14)
1404 mark_lines
[num_marks
][0] = letter
;
1405 mark_lines
[num_marks
][1] = cur_fline
;
1408 print_statusline("Invalid mark letter");
1412 static void goto_mark(void)
1417 print_statusline("Go to mark: ");
1418 letter
= less_getch(sizeof("Go to mark: ") - 1);
1421 if (isalpha(letter
)) {
1422 for (i
= 0; i
<= num_marks
; i
++)
1423 if (letter
== mark_lines
[i
][0]) {
1424 buffer_line(mark_lines
[i
][1]);
1427 if (num_marks
== 14 && letter
!= mark_lines
[14][0])
1428 print_statusline("Mark not set");
1430 print_statusline("Invalid mark letter");
1434 #if ENABLE_FEATURE_LESS_BRACKETS
1435 static char opp_bracket(char bracket
)
1438 case '{': case '[': /* '}' == '{' + 2. Same for '[' */
1440 case '(': /* ')' == '(' + 1 */
1452 static void match_right_bracket(char bracket
)
1456 if (strchr(flines
[cur_fline
], bracket
) == NULL
) {
1457 print_statusline("No bracket in top line");
1460 bracket
= opp_bracket(bracket
);
1461 for (i
= cur_fline
+ 1; i
< max_fline
; i
++) {
1462 if (strchr(flines
[i
], bracket
) != NULL
) {
1467 print_statusline("No matching bracket found");
1470 static void match_left_bracket(char bracket
)
1474 if (strchr(flines
[cur_fline
+ max_displayed_line
], bracket
) == NULL
) {
1475 print_statusline("No bracket in bottom line");
1479 bracket
= opp_bracket(bracket
);
1480 for (i
= cur_fline
+ max_displayed_line
; i
>= 0; i
--) {
1481 if (strchr(flines
[i
], bracket
) != NULL
) {
1486 print_statusline("No matching bracket found");
1488 #endif /* FEATURE_LESS_BRACKETS */
1490 static void keypress_process(int keypress
)
1493 case KEYCODE_DOWN
: case 'e': case 'j': case 0x0d:
1496 case KEYCODE_UP
: case 'y': case 'k':
1499 case KEYCODE_PAGEDOWN
: case ' ': case 'z': case 'f':
1500 buffer_down(max_displayed_line
+ 1);
1502 case KEYCODE_PAGEUP
: case 'w': case 'b':
1503 buffer_up(max_displayed_line
+ 1);
1506 buffer_down((max_displayed_line
+ 1) / 2);
1509 buffer_up((max_displayed_line
+ 1) / 2);
1511 case KEYCODE_HOME
: case 'g': case 'p': case '<': case '%':
1514 case KEYCODE_END
: case 'G': case '>':
1515 cur_fline
= MAXLINES
;
1517 buffer_line(cur_fline
);
1520 less_exit(EXIT_SUCCESS
);
1522 #if ENABLE_FEATURE_LESS_MARKS
1533 /* TODO: (1) also bind ^R, ^L to this?
1534 * (2) re-measure window size?
1542 save_input_to_file();
1547 #if ENABLE_FEATURE_LESS_FLAGS
1552 #if ENABLE_FEATURE_LESS_REGEXP
1554 option_mask32
&= ~LESS_STATE_MATCH_BACKWARDS
;
1558 goto_match(match_pos
+ 1);
1561 goto_match(match_pos
- 1);
1564 option_mask32
|= LESS_STATE_MATCH_BACKWARDS
;
1568 #if ENABLE_FEATURE_LESS_DASHCMD
1579 #if ENABLE_FEATURE_LESS_BRACKETS
1580 case '{': case '(': case '[':
1581 match_right_bracket(keypress
);
1583 case '}': case ')': case ']':
1584 match_left_bracket(keypress
);
1592 if (isdigit(keypress
))
1593 number_process(keypress
);
1596 static void sig_catcher(int sig
)
1601 #if ENABLE_FEATURE_LESS_WINCH
1602 static void sigwinch_handler(int sig UNUSED_PARAM
)
1608 int less_main(int argc
, char **argv
) MAIN_EXTERNALLY_VISIBLE
;
1609 int less_main(int argc
, char **argv
)
1613 /* TODO: -x: do not interpret backspace, -xx: tab also */
1614 /* -xxx: newline also */
1615 /* -w N: assume width N (-xxx -w 32: hex viewer of sorts) */
1616 getopt32(argv
, "EMmN~I" IF_FEATURE_LESS_DASHCMD("S"));
1622 /* Another popular pager, most, detects when stdout
1623 * is not a tty and turns into cat. This makes sense. */
1624 if (!isatty(STDOUT_FILENO
))
1625 return bb_cat(argv
);
1628 if (isatty(STDIN_FILENO
)) {
1629 /* Just "less"? No args and no redirection? */
1630 bb_error_msg("missing filename");
1634 filename
= xstrdup(files
[0]);
1637 if (option_mask32
& FLAG_TILDE
)
1638 empty_line_marker
= "";
1640 kbd_fd
= open(CURRENT_TTY
, O_RDONLY
);
1642 return bb_cat(argv
);
1645 tcgetattr(kbd_fd
, &term_orig
);
1646 term_less
= term_orig
;
1647 term_less
.c_lflag
&= ~(ICANON
| ECHO
);
1648 term_less
.c_iflag
&= ~(IXON
| ICRNL
);
1649 /*term_less.c_oflag &= ~ONLCR;*/
1650 term_less
.c_cc
[VMIN
] = 1;
1651 term_less
.c_cc
[VTIME
] = 0;
1653 IF_FEATURE_LESS_ASK_TERMINAL(G
.winsize_err
=) get_terminal_width_height(kbd_fd
, &width
, &max_displayed_line
);
1654 /* 20: two tabstops + 4 */
1655 if (width
< 20 || max_displayed_line
< 3)
1656 return bb_cat(argv
);
1657 max_displayed_line
-= 2;
1659 /* We want to restore term_orig on exit */
1660 bb_signals(BB_FATAL_SIGS
, sig_catcher
);
1661 #if ENABLE_FEATURE_LESS_WINCH
1662 signal(SIGWINCH
, sigwinch_handler
);
1665 buffer
= xmalloc((max_displayed_line
+1) * sizeof(char *));
1670 #if ENABLE_FEATURE_LESS_WINCH
1671 while (WINCH_COUNTER
) {
1674 IF_FEATURE_LESS_ASK_TERMINAL(G
.winsize_err
=) get_terminal_width_height(kbd_fd
, &width
, &max_displayed_line
);
1675 IF_FEATURE_LESS_ASK_TERMINAL(got_size
:)
1676 /* 20: two tabstops + 4 */
1679 if (max_displayed_line
< 3)
1680 max_displayed_line
= 3;
1681 max_displayed_line
-= 2;
1683 buffer
= xmalloc((max_displayed_line
+1) * sizeof(char *));
1684 /* Avoid re-wrap and/or redraw if we already know
1685 * we need to do it again. These ops are expensive */
1691 buffer_fill_and_print();
1692 /* This took some time. Loop back and check,
1693 * were there another SIGWINCH? */
1695 keypress
= less_getch(-1); /* -1: do not position cursor */
1696 # if ENABLE_FEATURE_LESS_ASK_TERMINAL
1697 if ((int32_t)keypress
== KEYCODE_CURSOR_POS
) {
1698 uint32_t rc
= (keypress
>> 32);
1699 width
= (rc
& 0x7fff);
1700 max_displayed_line
= ((rc
>> 16) & 0x7fff);
1705 keypress
= less_getch(-1); /* -1: do not position cursor */
1707 keypress_process(keypress
);
1712 Help text of less version 418 is below.
1713 If you are implementing something, keeping
1714 key and/or command line switch compatibility is a good idea:
1717 SUMMARY OF LESS COMMANDS
1719 Commands marked with * may be preceded by a number, N.
1720 Notes in parentheses indicate the behavior if N is given.
1721 h H Display this help.
1723 ---------------------------------------------------------------------------
1725 e ^E j ^N CR * Forward one line (or N lines).
1726 y ^Y k ^K ^P * Backward one line (or N lines).
1727 f ^F ^V SPACE * Forward one window (or N lines).
1728 b ^B ESC-v * Backward one window (or N lines).
1729 z * Forward one window (and set window to N).
1730 w * Backward one window (and set window to N).
1731 ESC-SPACE * Forward one window, but don't stop at end-of-file.
1732 d ^D * Forward one half-window (and set half-window to N).
1733 u ^U * Backward one half-window (and set half-window to N).
1734 ESC-) RightArrow * Left one half screen width (or N positions).
1735 ESC-( LeftArrow * Right one half screen width (or N positions).
1736 F Forward forever; like "tail -f".
1737 r ^R ^L Repaint screen.
1738 R Repaint screen, discarding buffered input.
1739 ---------------------------------------------------
1740 Default "window" is the screen height.
1741 Default "half-window" is half of the screen height.
1742 ---------------------------------------------------------------------------
1744 /pattern * Search forward for (N-th) matching line.
1745 ?pattern * Search backward for (N-th) matching line.
1746 n * Repeat previous search (for N-th occurrence).
1747 N * Repeat previous search in reverse direction.
1748 ESC-n * Repeat previous search, spanning files.
1749 ESC-N * Repeat previous search, reverse dir. & spanning files.
1750 ESC-u Undo (toggle) search highlighting.
1751 ---------------------------------------------------
1752 Search patterns may be modified by one or more of:
1753 ^N or ! Search for NON-matching lines.
1754 ^E or * Search multiple files (pass thru END OF FILE).
1755 ^F or @ Start search at FIRST file (for /) or last file (for ?).
1756 ^K Highlight matches, but don't move (KEEP position).
1757 ^R Don't use REGULAR EXPRESSIONS.
1758 ---------------------------------------------------------------------------
1760 g < ESC-< * Go to first line in file (or line N).
1761 G > ESC-> * Go to last line in file (or line N).
1762 p % * Go to beginning of file (or N percent into file).
1763 t * Go to the (N-th) next tag.
1764 T * Go to the (N-th) previous tag.
1765 { ( [ * Find close bracket } ) ].
1766 } ) ] * Find open bracket { ( [.
1767 ESC-^F <c1> <c2> * Find close bracket <c2>.
1768 ESC-^B <c1> <c2> * Find open bracket <c1>
1769 ---------------------------------------------------
1770 Each "find close bracket" command goes forward to the close bracket
1771 matching the (N-th) open bracket in the top line.
1772 Each "find open bracket" command goes backward to the open bracket
1773 matching the (N-th) close bracket in the bottom line.
1774 m<letter> Mark the current position with <letter>.
1775 '<letter> Go to a previously marked position.
1776 '' Go to the previous position.
1778 ---------------------------------------------------
1779 A mark is any upper-case or lower-case letter.
1780 Certain marks are predefined:
1781 ^ means beginning of the file
1782 $ means end of the file
1783 ---------------------------------------------------------------------------
1785 :e [file] Examine a new file.
1787 :n * Examine the (N-th) next file from the command line.
1788 :p * Examine the (N-th) previous file from the command line.
1789 :x * Examine the first (or N-th) file from the command line.
1790 :d Delete the current file from the command line list.
1791 = ^G :f Print current file name.
1792 ---------------------------------------------------------------------------
1793 MISCELLANEOUS COMMANDS
1794 -<flag> Toggle a command line option [see OPTIONS below].
1795 --<name> Toggle a command line option, by name.
1796 _<flag> Display the setting of a command line option.
1797 __<name> Display the setting of an option, by name.
1798 +cmd Execute the less cmd each time a new file is examined.
1799 !command Execute the shell command with $SHELL.
1800 |Xcommand Pipe file between current pos & mark X to shell command.
1801 v Edit the current file with $VISUAL or $EDITOR.
1802 V Print version number of "less".
1803 ---------------------------------------------------------------------------
1805 Most options may be changed either on the command line,
1806 or from within less by using the - or -- command.
1807 Options may be given in one of two forms: either a single
1808 character preceded by a -, or a name preceeded by --.
1810 Display help (from command line).
1811 -a ........ --search-skip-screen
1812 Forward search skips current screen.
1813 -b [N] .... --buffers=[N]
1815 -B ........ --auto-buffers
1816 Don't automatically allocate buffers for pipes.
1817 -c ........ --clear-screen
1818 Repaint by clearing rather than scrolling.
1821 -D [xn.n] . --color=xn.n
1822 Set screen colors. (MS-DOS only)
1823 -e -E .... --quit-at-eof --QUIT-AT-EOF
1824 Quit at end of file.
1826 Force open non-regular files.
1827 -F ........ --quit-if-one-screen
1828 Quit if entire file fits on first screen.
1829 -g ........ --hilite-search
1830 Highlight only last match for searches.
1831 -G ........ --HILITE-SEARCH
1832 Don't highlight any matches for searches.
1833 -h [N] .... --max-back-scroll=[N]
1834 Backward scroll limit.
1835 -i ........ --ignore-case
1836 Ignore case in searches that do not contain uppercase.
1837 -I ........ --IGNORE-CASE
1838 Ignore case in all searches.
1839 -j [N] .... --jump-target=[N]
1840 Screen position of target lines.
1841 -J ........ --status-column
1842 Display a status column at left edge of screen.
1843 -k [file] . --lesskey-file=[file]
1845 -L ........ --no-lessopen
1846 Ignore the LESSOPEN environment variable.
1847 -m -M .... --long-prompt --LONG-PROMPT
1849 -n -N .... --line-numbers --LINE-NUMBERS
1850 Don't use line numbers.
1851 -o [file] . --log-file=[file]
1852 Copy to log file (standard input only).
1853 -O [file] . --LOG-FILE=[file]
1854 Copy to log file (unconditionally overwrite).
1855 -p [pattern] --pattern=[pattern]
1856 Start at pattern (from command line).
1857 -P [prompt] --prompt=[prompt]
1859 -q -Q .... --quiet --QUIET --silent --SILENT
1860 Quiet the terminal bell.
1861 -r -R .... --raw-control-chars --RAW-CONTROL-CHARS
1862 Output "raw" control characters.
1863 -s ........ --squeeze-blank-lines
1864 Squeeze multiple blank lines.
1865 -S ........ --chop-long-lines
1867 -t [tag] .. --tag=[tag]
1869 -T [tagsfile] --tag-file=[tagsfile]
1870 Use an alternate tags file.
1871 -u -U .... --underline-special --UNDERLINE-SPECIAL
1872 Change handling of backspaces.
1873 -V ........ --version
1874 Display the version number of "less".
1875 -w ........ --hilite-unread
1876 Highlight first new line after forward-screen.
1877 -W ........ --HILITE-UNREAD
1878 Highlight first new line after any forward movement.
1879 -x [N[,...]] --tabs=[N[,...]]
1881 -X ........ --no-init
1882 Don't use termcap init/deinit strings.
1884 Don't use termcap keypad init/deinit strings.
1885 -y [N] .... --max-forw-scroll=[N]
1886 Forward scroll limit.
1887 -z [N] .... --window=[N]
1889 -" [c[c]] . --quotes=[c[c]]
1890 Set shell quote characters.
1892 Don't display tildes after end of file.
1893 -# [N] .... --shift=[N]
1894 Horizontal scroll amount (0 = one half screen width)
1896 ---------------------------------------------------------------------------
1898 These keys can be used to edit text being entered
1899 on the "command line" at the bottom of the screen.
1900 RightArrow ESC-l Move cursor right one character.
1901 LeftArrow ESC-h Move cursor left one character.
1902 CNTL-RightArrow ESC-RightArrow ESC-w Move cursor right one word.
1903 CNTL-LeftArrow ESC-LeftArrow ESC-b Move cursor left one word.
1904 HOME ESC-0 Move cursor to start of line.
1905 END ESC-$ Move cursor to end of line.
1906 BACKSPACE Delete char to left of cursor.
1907 DELETE ESC-x Delete char under cursor.
1908 CNTL-BACKSPACE ESC-BACKSPACE Delete word to left of cursor.
1909 CNTL-DELETE ESC-DELETE ESC-X Delete word under cursor.
1910 CNTL-U ESC (MS-DOS only) Delete entire line.
1911 UpArrow ESC-k Retrieve previous command line.
1912 DownArrow ESC-j Retrieve next command line.
1913 TAB Complete filename & cycle.
1914 SHIFT-TAB ESC-TAB Complete filename & reverse cycle.
1915 CNTL-L Complete filename, list all.