forked from rustyrussell/bitcoin-iterate
/
parse.c
204 lines (177 loc) · 5.11 KB
/
parse.c
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#include <ccan/likely/likely.h>
#include <ccan/endian/endian.h>
#include <ccan/tal/tal.h>
#include <ccan/err/err.h>
#include <string.h>
#include <unistd.h>
#include <assert.h>
#include "types.h"
#include "parse.h"
#include "space.h"
static u64 pull_varint(struct file *f, off_t *poff)
{
u64 ret;
u8 v[9], *p;
if (likely(f->mmap))
p = f->mmap + *poff;
else {
/* We could do a short read here, that's OK. */
if (pread(f->fd, v, sizeof(v), *poff) < 1)
err(1, "Pulling varint from %s offset %llu\n",
f->name, (long long)*poff);
p = v;
}
if (*p < 0xfd) {
ret = p[0];
*poff += 1;
} else if (*p == 0xfd) {
ret = ((u64)p[2] << 8) + p[1];
*poff += 3;
} else if (*p == 0xfe) {
ret = ((u64)p[4] << 24) + ((u64)p[3] << 16)
+ ((u64)p[2] << 8) + p[1];
*poff += 5;
} else {
ret = ((u64)p[8] << 56) + ((u64)p[7] << 48)
+ ((u64)p[6] << 40) + ((u64)p[5] << 32)
+ ((u64)p[4] << 24) + ((u64)p[3] << 16)
+ ((u64)p[2] << 8) + p[1];
*poff += 9;
}
return ret;
}
static void pull_bytes(struct file *f, off_t *poff, void *dst, size_t num)
{
if (likely(f->mmap))
memcpy(dst, f->mmap + *poff, num);
else
file_read(f, *poff, num, dst);
*poff += num;
}
static u32 pull_u32(struct file *f, off_t *poff)
{
le32 ret;
pull_bytes(f, poff, &ret, sizeof(ret));
return le32_to_cpu(ret);
}
static u64 pull_u64(struct file *f, off_t *poff)
{
le64 ret;
pull_bytes(f, poff, &ret, sizeof(ret));
return le64_to_cpu(ret);
}
static void pull_hash(struct file *f, off_t *poff, u8 dst[32])
{
pull_bytes(f, poff, dst, 32);
}
static void read_input(struct space *space, struct file *f, off_t *poff,
struct bitcoin_transaction_input *input)
{
pull_hash(f, poff, input->hash);
input->index = pull_u32(f, poff);
input->script_length = pull_varint(f, poff);
input->script = space_alloc(space, input->script_length);
pull_bytes(f, poff, input->script, input->script_length);
input->sequence_number = pull_u32(f, poff);
}
static void read_output(struct space *space, struct file *f, off_t *poff,
struct bitcoin_transaction_output *output)
{
output->amount = pull_u64(f, poff);
output->script_length = pull_varint(f, poff);
output->script = space_alloc(space, output->script_length);
pull_bytes(f, poff, output->script, output->script_length);
}
void read_bitcoin_transaction(struct space *space,
struct bitcoin_transaction *trans,
struct file *f, off_t *poff)
{
size_t i;
off_t start = *poff;
SHA256_CTX sha256;
trans->version = pull_u32(f, poff);
trans->input_count = pull_varint(f, poff);
trans->input = space_alloc_arr(space,
struct bitcoin_transaction_input,
trans->input_count);
for (i = 0; i < trans->input_count; i++)
read_input(space, f, poff, trans->input + i);
trans->output_count = pull_varint(f, poff);
trans->output = space_alloc_arr(space,
struct bitcoin_transaction_output,
trans->output_count);
for (i = 0; i < trans->output_count; i++)
read_output(space, f, poff, trans->output + i);
trans->lock_time = pull_u32(f, poff);
/* Bitcoin uses double sha (it's not quite known why...) */
SHA256_Init(&sha256);
if (likely(f->mmap)) {
SHA256_Update(&sha256, f->mmap + start, *poff - start);
} else {
u8 *buf = tal_arr(NULL, u8, *poff - start);
file_read(f, start, *poff - start, buf);
SHA256_Update(&sha256, buf, *poff - start);
tal_free(buf);
}
SHA256_Final(trans->sha256, &sha256);
SHA256_Init(&sha256);
SHA256_Update(&sha256, trans->sha256, sizeof(trans->sha256));
SHA256_Final(trans->sha256, &sha256);
trans->len = *poff - start;
}
/* Inefficient, but blk*.dat can have zero(?) padding. */
bool next_block_header_prefix(struct file *f, off_t *off, const u32 marker)
{
while (*off + sizeof(u32) <= f->len) {
u32 val;
/* Inefficent, but don't expect it to be far. */
val = pull_u32(f, off);
*off -= 4;
if (val == marker)
return true;
(*off)++;
}
return false;
}
bool
read_bitcoin_block_header(struct bitcoin_block *block,
struct file *f, off_t *off,
u8 block_md[SHA256_DIGEST_LENGTH],
const u32 marker)
{
SHA256_CTX sha256;
off_t start;
block->D9B4BEF9 = pull_u32(f, off);
assert(block->D9B4BEF9 == marker);
block->len = pull_u32(f, off);
/* Hash only covers version to nonce, inclusive. */
start = *off;
block->version = pull_u32(f, off);
pull_hash(f, off, block->prev_hash);
pull_hash(f, off, block->merkle_hash);
block->timestamp = pull_u32(f, off);
block->target = pull_u32(f, off);
block->nonce = pull_u32(f, off);
/* Bitcoin uses double sha (it's not quite known why...) */
SHA256_Init(&sha256);
if (likely(f->mmap)) {
SHA256_Update(&sha256, f->mmap + start, *off - start);
} else {
u8 *buf = tal_arr(NULL, u8, *off - start);
file_read(f, start, *off - start, buf);
SHA256_Update(&sha256, buf, *off - start);
tal_free(buf);
}
SHA256_Final(block_md, &sha256);
SHA256_Init(&sha256);
SHA256_Update(&sha256, block_md, SHA256_DIGEST_LENGTH);
SHA256_Final(block_md, &sha256);
block->transaction_count = pull_varint(f, off);
return block;
}
void skip_bitcoin_transactions(const struct bitcoin_block *b,
off_t block_start,
off_t *off)
{
*off = block_start + 8 + b->len;
}