mirror of
https://github.com/topjohnwu/Magisk.git
synced 2024-12-25 22:07:38 +00:00
84 lines
2.3 KiB
C
84 lines
2.3 KiB
C
|
/* b64xz.c - Base64-XZ Extractor
|
||
|
|
*
|
||
|
|
* This program expects data from stdin. The data should be compressed with xz and
|
||
|
|
* then encoded into base64 format. What b64xz does is basically the reverse of the
|
||
|
|
* mentioned process: decode base64 to uint8_ts, decompress xz, then dump to stdout
|
||
|
|
*
|
||
|
|
* The compiled binary will be hex-dumped into update-binary
|
||
|
|
* Busybox will be xz-compressed, base64 encoded and dumped into update-binary
|
||
|
|
* This program is to recover busybox for Magisk installation environment
|
||
|
|
*
|
||
|
|
* I intentionally removed stdio. This will result in a smaller binary size because
|
||
|
|
* all I/O are handled by system calls (read/write) instead of libc wrappers
|
||
|
|
*/
|
||
|
|
|
||
|
|
#include <unistd.h>
|
||
|
|
#include <lzma.h>
|
||
|
|
|
||
|
|
#define BUFSIZE 8192
|
||
|
|
|
||
|
|
static const char trans_tbl[] =
|
||
|
|
"|$$$}rstuvwxyz{$$$$$$$>?@ABCDEFGHIJKLMNOPQRSTUVW$$$$$$XYZ[\\]^_`abcdefghijklmnopq";
|
||
|
|
|
||
|
|
static void decodeblock(uint8_t* in, uint8_t* out) {
|
||
|
|
out[0] = (uint8_t)(in[0] << 2 | in[1] >> 4);
|
||
|
|
out[1] = (uint8_t)(in[1] << 4 | in[2] >> 2);
|
||
|
|
out[2] = (uint8_t)(((in[2] << 6) & 0xc0) | in[3]);
|
||
|
|
}
|
||
|
|
|
||
|
|
static int unxz(lzma_stream *strm, void *buf, size_t size) {
|
||
|
|
lzma_ret ret = 0;
|
||
|
|
uint8_t out[BUFSIZE];
|
||
|
|
strm->next_in = buf;
|
||
|
|
strm->avail_in = size;
|
||
|
|
do {
|
||
|
|
strm->next_out = out;
|
||
|
|
strm->avail_out = sizeof(out);
|
||
|
|
ret = lzma_code(strm, LZMA_RUN);
|
||
|
|
write(STDOUT_FILENO, out, sizeof(out) - strm->avail_out);
|
||
|
|
} while (strm->avail_out == 0 && ret == LZMA_OK);
|
||
|
|
|
||
|
|
if (ret != LZMA_OK && ret != LZMA_STREAM_END)
|
||
|
|
write(STDERR_FILENO, "LZMA error!\n", 13);
|
||
|
|
return ret;
|
||
|
|
}
|
||
|
|
|
||
|
|
int main(int argc, char const* argv[]) {
|
||
|
|
if (argc > 1)
|
||
|
|
return 0;
|
||
|
|
|
||
|
|
uint8_t in[4], buf[BUFSIZE];
|
||
|
|
int len = 0, pos = 0;
|
||
|
|
char c;
|
||
|
|
|
||
|
|
// Setup lzma stream
|
||
|
|
lzma_stream strm = LZMA_STREAM_INIT;
|
||
|
|
if (lzma_auto_decoder(&strm, UINT64_MAX, 0) != LZMA_OK) {
|
||
|
|
write(STDERR_FILENO, "Unable to init lzma stream\n", 28);
|
||
|
|
return 1;
|
||
|
|
}
|
||
|
|
|
||
|
|
while (read(STDIN_FILENO, &c, sizeof(c)) == 1) {
|
||
|
|
c = ((c < 43 || c > 122) ? -1 : (trans_tbl[c - 43] == '$' ? -1 : trans_tbl[c - 43] - 62));
|
||
|
|
if (c >= 0)
|
||
|
|
in[len++] = c;
|
||
|
|
if (len < 4)
|
||
|
|
continue;
|
||
|
|
len = 0;
|
||
|
|
decodeblock(in, buf + pos);
|
||
|
|
pos += 3;
|
||
|
|
if (pos > sizeof(buf) - 3) {
|
||
|
|
// Buffer is full, unxz
|
||
|
|
if (unxz(&strm, buf, pos))
|
||
|
|
return 1;
|
||
|
|
pos = 0;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
if (pos) {
|
||
|
|
if (unxz(&strm, buf, pos))
|
||
|
|
return 1;
|
||
|
|
}
|
||
|
|
lzma_end(&strm);
|
||
|
|
return 0;
|
||
|
|
}
|