busybox/miscutils/hexedit.c

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/*
* 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"
//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;
}