summaryrefslogtreecommitdiff
path: root/miscutils/hexedit.c
blob: 95c930d123485e214063a0366101f3b1ec29c995 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
/*
 * Copyright (C) 2017 Denys Vlasenko <vda.linux@googlemail.com>
 *
 * Licensed under GPLv2, see file LICENSE in this source tree.
 */
//config:config HEXEDIT
//config:	bool "hexedit (20 kb)"
//config:	default y
//config:	help
//config:	Edit file in hexadecimal.

//applet:IF_HEXEDIT(APPLET(hexedit, BB_DIR_USR_BIN, BB_SUID_DROP))

//kbuild:lib-$(CONFIG_HEXEDIT) += hexedit.o

#include "libbb.h"

#define ESC		"\033"
#define HOME		ESC"[H"
#define CLEAR		ESC"[J"
#define CLEAR_TILL_EOL	ESC"[K"
#define SET_ALT_SCR	ESC"[?1049h"
#define POP_ALT_SCR	ESC"[?1049l"

#undef CTRL
#define CTRL(c)  ((c) & (uint8_t)~0x60)

struct globals {
	smallint half;
	smallint in_read_key;
	int fd;
	unsigned height;
	unsigned row;
	unsigned pagesize;
	uint8_t *baseaddr;
	uint8_t *current_byte;
	uint8_t *eof_byte;
	off_t size;
	off_t offset;
	/* needs to be zero-inited, thus keeping it in G: */
	char read_key_buffer[KEYCODE_BUFFER_SIZE];
	struct termios orig_termios;
};
#define G (*ptr_to_globals)
#define INIT_G() do { \
	SET_PTR_TO_GLOBALS(xzalloc(sizeof(G))); \
} while (0)

//TODO: move to libbb
#if defined(__x86_64__) || defined(i386)
# define G_pagesize 4096
# define INIT_PAGESIZE() ((void)0)
#else
# define G_pagesize (G.pagesize)
# define INIT_PAGESIZE() ((void)(G.pagesize = getpagesize()))
#endif

/* hopefully there aren't arches with PAGE_SIZE > 64k */
#define G_mapsize  (64*1024)

/* "12ef5670 (xx )*16 _1_3_5_7_9abcdef\n"NUL */
#define LINEBUF_SIZE (8 + 1 + 3*16 + 16 + 1 + 1 /*paranoia:*/ + 13)

static void restore_term(void)
{
	tcsetattr_stdin_TCSANOW(&G.orig_termios);
	printf(POP_ALT_SCR);
	fflush_all();
}

static void sig_catcher(int sig)
{
	if (!G.in_read_key) {
		/* now it's not safe to do I/O, just inform the main loop */
		bb_got_signal = sig;
		return;
	}
	restore_term();
	kill_myself_with_sig(sig);
}

static int format_line(char *hex, uint8_t *data, off_t offset)
{
	int ofs_pos;
	char *text;
	uint8_t *end, *end1;

#if 1
	/* Can be more than 4Gb, thus >8 chars, thus use a variable - don't assume 8! */
	ofs_pos = sprintf(hex, "%08"OFF_FMT"x ", offset);
#else
	if (offset <= 0xffff)
		ofs_pos = sprintf(hex, "%04"OFF_FMT"x ", offset);
	else
		ofs_pos = sprintf(hex, "%08"OFF_FMT"x ", offset);
#endif
	hex += ofs_pos;

	text = hex + 16 * 3;
	end1 = data + 15;
	if ((G.size - offset) > 0) {
		end = end1;
		if ((G.size - offset) <= 15)
			end = data + (G.size - offset) - 1;
		while (data <= end) {
			uint8_t c = *data++;
			*hex++ = bb_hexdigits_upcase[c >> 4];
			*hex++ = bb_hexdigits_upcase[c & 0xf];
			*hex++ = ' ';
			if (c < ' ' || c > 0x7e)
				c = '.';
			*text++ = c;
		}
	}
	while (data <= end1) {
		*hex++ = ' ';
		*hex++ = ' ';
		*hex++ = ' ';
		*text++ = ' ';
		data++;
	}
	*text = '\0';

	return ofs_pos;
}

static void redraw(unsigned cursor)
{
	uint8_t *data;
	off_t offset;
	unsigned i, pos;

	printf(HOME CLEAR);

	/* if cursor is past end of screen, how many lines to move down? */
	i = (cursor / 16) - G.height + 1;
	if ((int)i < 0)
		i = 0;

	data = G.baseaddr + i * 16;
	offset = G.offset + i * 16;
	cursor -= i * 16;
	pos = i = 0;
	while (i < G.height) {
		char buf[LINEBUF_SIZE];
		pos = format_line(buf, data, offset);
		printf(
			"\r\n%s" + (!i) * 2, /* print \r\n only on 2nd line and later */
			buf
		);
		data += 16;
		offset += 16;
		i++;
	}

	printf(ESC"[%u;%uH", 1 + cursor / 16, 1 + pos + (cursor & 0xf) * 3);
}

static void redraw_cur_line(void)
{
	char buf[LINEBUF_SIZE];
	uint8_t *data;
	off_t offset;
	int column;

	column = (0xf & (uintptr_t)G.current_byte);
	data = G.current_byte - column;
	offset = G.offset + (data - G.baseaddr);

	column = column*3 + G.half;
	column += format_line(buf, data, offset);
	printf("%s"
		"\r"
		"%.*s",
		buf + column,
		column, buf
	);
}

/* if remappers return 0, no change was done */
static int remap(unsigned cur_pos)
{
	if (G.baseaddr)
		munmap(G.baseaddr, G_mapsize);

	G.baseaddr = mmap(NULL,
		G_mapsize,
		PROT_READ | PROT_WRITE,
		MAP_SHARED,
		G.fd,
		G.offset
	);
	if (G.baseaddr == MAP_FAILED) {
		restore_term();
		bb_perror_msg_and_die("mmap");
	}

	G.current_byte = G.baseaddr + cur_pos;

	G.eof_byte = G.baseaddr + G_mapsize;
	if ((G.size - G.offset) < G_mapsize) {
		/* mapping covers tail of the file */
		/* we do have a mapped byte which is past eof */
		G.eof_byte = G.baseaddr + (G.size - G.offset);
	}
	return 1;
}
static int move_mapping_further(void)
{
	unsigned pos;
	unsigned pagesize;

	if ((G.size - G.offset) < G_mapsize)
		return 0; /* can't move mapping even further, it's at the end already */

	pagesize = G_pagesize; /* constant on most arches */
	pos = G.current_byte - G.baseaddr;
	if (pos >= pagesize) {
		/* move offset up until current position is in 1st page */
		do {
			G.offset += pagesize;
			if (G.offset == 0) { /* whoops */
				G.offset -= pagesize;
				break;
			}
			pos -= pagesize;
		} while (pos >= pagesize);
		return remap(pos);
	}
	return 0;
}
static int move_mapping_lower(void)
{
	unsigned pos;
	unsigned pagesize;

	if (G.offset == 0)
		return 0; /* we are at 0 already */

	pagesize = G_pagesize; /* constant on most arches */
	pos = G.current_byte - G.baseaddr;

	/* move offset down until current position is in last page */
	pos += pagesize;
	while (pos < G_mapsize) {
		pos += pagesize;
		G.offset -= pagesize;
		if (G.offset == 0)
			break;
	}
	pos -= pagesize;

	return remap(pos);
}

//usage:#define hexedit_trivial_usage
//usage:	"FILE"
//usage:#define hexedit_full_usage "\n\n"
//usage:	"Edit FILE in hexadecimal"
int hexedit_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int hexedit_main(int argc UNUSED_PARAM, char **argv)
{
	INIT_G();
	INIT_PAGESIZE();

	get_terminal_width_height(-1, NULL, &G.height);
	if (1) {
		/* reduce number of write() syscalls while PgUp/Down: fully buffered output */
		unsigned sz = (G.height | 0xf) * LINEBUF_SIZE;
		setvbuf(stdout, xmalloc(sz), _IOFBF, sz);
	}

	getopt32(argv, "^" "" "\0" "=1"/*one arg*/);
	argv += optind;

	G.fd = xopen(*argv, O_RDWR);
	G.size = xlseek(G.fd, 0, SEEK_END);

	/* TERMIOS_RAW_CRNL suppresses \n -> \r\n translation, helps with down-arrow */
	printf(SET_ALT_SCR);
	set_termios_to_raw(STDIN_FILENO, &G.orig_termios, TERMIOS_RAW_CRNL);
	bb_signals(BB_FATAL_SIGS, sig_catcher);

	remap(0);
	redraw(0);

//TODO: //Home/End: start/end of line; '<'/'>': start/end of file
	//Backspace: undo
	//Ctrl-L: redraw
	//Ctrl-Z: suspend
	//'/', Ctrl-S: search
//TODO: detect window resize

	for (;;) {
		unsigned cnt;
		int32_t key = key; /* for compiler */
		uint8_t byte;

		fflush_all();
		G.in_read_key = 1;
		if (!bb_got_signal)
			key = read_key(STDIN_FILENO, G.read_key_buffer, -1);
		G.in_read_key = 0;
		if (bb_got_signal)
			key = CTRL('X');

		cnt = 1;
		if ((unsigned)(key - 'A') <= 'Z' - 'A')
			key |= 0x20; /* convert A-Z to a-z */
		switch (key) {
		case 'a': case 'b': case 'c': case 'd': case 'e': case 'f':
			/* convert to '0'+10...15 */
			key = key - ('a' - '0' - 10);
			/* fall through */
		case '0': case '1': case '2': case '3': case '4':
		case '5': case '6': case '7': case '8': case '9':
			if (G.current_byte == G.eof_byte) {
				if (!move_mapping_further()) {
					/* already at EOF; extend the file */
					if (++G.size <= 0 /* overflow? */
					 || ftruncate(G.fd, G.size) != 0 /* error extending? (e.g. block dev) */
					) {
						G.size--;
						break;
					}
					G.eof_byte++;
				}
			}
			key -= '0';
			byte = *G.current_byte & 0xf0;
			if (!G.half) {
				byte = *G.current_byte & 0x0f;
				key <<= 4;
			}
			*G.current_byte = byte + key;
			/* can't just print one updated hex char: need to update right-hand ASCII too */
			redraw_cur_line();
			/* fall through */
		case KEYCODE_RIGHT:
			if (G.current_byte == G.eof_byte)
				break; /* eof - don't allow going past it */
			byte = *G.current_byte;
			if (!G.half) {
				G.half = 1;
				putchar(bb_hexdigits_upcase[byte >> 4]);
			} else {
				G.half = 0;
				G.current_byte++;
				if ((0xf & (uintptr_t)G.current_byte) == 0) {
					/* rightmost pos, wrap to next line */
					if (G.current_byte == G.eof_byte)
						move_mapping_further();
					printf(ESC"[46D"); /* cursor left 3*15 + 1 chars */
					goto down;
				}
				putchar(bb_hexdigits_upcase[byte & 0xf]);
				putchar(' ');
			}
			break;
		case KEYCODE_PAGEDOWN:
			cnt = G.height;
		case KEYCODE_DOWN:
 k_down:
			G.current_byte += 16;
			if (G.current_byte >= G.eof_byte) {
				move_mapping_further();
				if (G.current_byte > G.eof_byte) {
					/* _after_ eof - don't allow this */
					G.current_byte -= 16;
					break;
				}
			}
 down:
			putchar('\n'); /* down one line, possibly scroll screen */
			G.row++;
			if (G.row >= G.height) {
				G.row--;
				redraw_cur_line();
			}
			if (--cnt)
				goto k_down;
			break;

		case KEYCODE_LEFT:
			if (G.half) {
				G.half = 0;
				printf(ESC"[D");
				break;
			}
			if ((0xf & (uintptr_t)G.current_byte) == 0) {
				/* leftmost pos, wrap to prev line */
				if (G.current_byte == G.baseaddr) {
					if (!move_mapping_lower())
						break; /* first line, don't do anything */
				}
				G.half = 1;
				G.current_byte--;
				printf(ESC"[46C"); /* cursor right 3*15 + 1 chars */
				goto up;
			}
			G.half = 1;
			G.current_byte--;
			printf(ESC"[2D");
			break;
		case KEYCODE_PAGEUP:
			cnt = G.height;
		case KEYCODE_UP:
 k_up:
			if ((G.current_byte - G.baseaddr) < 16) {
				if (!move_mapping_lower())
					break; /* already at 0, stop */
			}
			G.current_byte -= 16;
 up:
			if (G.row != 0) {
				G.row--;
				printf(ESC"[A"); /* up (won't scroll) */
			} else {
				//printf(ESC"[T"); /* scroll up */ - not implemented on Linux VT!
				printf(ESC"M"); /* scroll up */
				redraw_cur_line();
			}
			if (--cnt)
				goto k_up;
			break;

		case '\n':
		case '\r':
			/* [Enter]: goto specified position */
			{
				char buf[sizeof(G.offset)*3 + 4];
				printf(ESC"[999;1H" CLEAR_TILL_EOL); /* go to last line */
				if (read_line_input(NULL, "Go to (dec,0Xhex,0oct): ", buf, sizeof(buf)) > 0) {
					off_t t;
					unsigned cursor;

					t = bb_strtoull(buf, NULL, 0);
					if (t >= G.size)
						t = G.size - 1;
					cursor = t & (G_pagesize - 1);
					t -= cursor;
					if (t < 0)
						cursor = t = 0;
					if (t != 0 && cursor < 0x1ff) {
						/* very close to end of page, possibly to EOF */
						/* move one page lower */
						t -= G_pagesize;
						cursor += G_pagesize;
					}
					G.offset = t;
					remap(cursor);
					redraw(cursor);
					break;
				}
				/* ^C/EOF/error: fall through to exiting */
			}
		case CTRL('X'):
			restore_term();
			return EXIT_SUCCESS;
		} /* switch */
	} /* for (;;) */

	/* not reached */
	return EXIT_SUCCESS;
}