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#include "config.h"
#include <iostream>
#include <cstring>
#include "hash.hh"
#include "archive.hh"
#include "util.hh"
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
namespace nix {
Hash::Hash()
{
type = htUnknown;
hashSize = 0;
memset(hash, 0, maxHashSize);
}
Hash::Hash(HashType type)
{
this->type = type;
hashSize = gcry_md_get_algo_dlen(type);
if (hashSize == 0) throw Error("unknown hash type");
assert(hashSize <= maxHashSize);
memset(hash, 0, maxHashSize);
}
bool Hash::operator == (const Hash & h2) const
{
if (hashSize != h2.hashSize) return false;
for (unsigned int i = 0; i < hashSize; i++)
if (hash[i] != h2.hash[i]) return false;
return true;
}
bool Hash::operator != (const Hash & h2) const
{
return !(*this == h2);
}
bool Hash::operator < (const Hash & h) const
{
for (unsigned int i = 0; i < hashSize; i++) {
if (hash[i] < h.hash[i]) return true;
if (hash[i] > h.hash[i]) return false;
}
return false;
}
const string base16Chars = "0123456789abcdef";
string printHash(const Hash & hash)
{
char buf[hash.hashSize * 2];
for (unsigned int i = 0; i < hash.hashSize; i++) {
buf[i * 2] = base16Chars[hash.hash[i] >> 4];
buf[i * 2 + 1] = base16Chars[hash.hash[i] & 0x0f];
}
return string(buf, hash.hashSize * 2);
}
Hash parseHash(HashType ht, const string & s)
{
Hash hash(ht);
if (s.length() != hash.hashSize * 2)
throw Error(format("invalid hash `%1%'") % s);
for (unsigned int i = 0; i < hash.hashSize; i++) {
string s2(s, i * 2, 2);
if (!isxdigit(s2[0]) || !isxdigit(s2[1]))
throw Error(format("invalid hash `%1%'") % s);
std::istringstream str(s2);
int n;
str >> std::hex >> n;
hash.hash[i] = n;
}
return hash;
}
unsigned int hashLength32(const Hash & hash)
{
return (hash.hashSize * 8 - 1) / 5 + 1;
}
// omitted: E O U T
const string base32Chars = "0123456789abcdfghijklmnpqrsvwxyz";
string printHash32(const Hash & hash)
{
Hash hash2(hash);
unsigned int len = hashLength32(hash);
string s;
s.reserve(len);
for (int n = len - 1; n >= 0; n--) {
unsigned int b = n * 5;
unsigned int i = b / 8;
unsigned int j = b % 8;
unsigned char c =
(hash.hash[i] >> j)
| (i >= hash.hashSize - 1 ? 0 : hash.hash[i + 1] << (8 - j));
s.push_back(base32Chars[c & 0x1f]);
}
return s;
}
string printHash16or32(const Hash & hash)
{
return hash.type == htMD5 ? printHash(hash) : printHash32(hash);
}
Hash parseHash32(HashType ht, const string & s)
{
Hash hash(ht);
unsigned int len = hashLength32(ht);
assert(s.size() == len);
for (unsigned int n = 0; n < len; ++n) {
char c = s[len - n - 1];
unsigned char digit;
for (digit = 0; digit < base32Chars.size(); ++digit) /* !!! slow */
if (base32Chars[digit] == c) break;
if (digit >= 32)
throw Error(format("invalid base-32 hash '%1%'") % s);
unsigned int b = n * 5;
unsigned int i = b / 8;
unsigned int j = b % 8;
hash.hash[i] |= digit << j;
if (i < hash.hashSize - 1) hash.hash[i + 1] |= digit >> (8 - j);
}
return hash;
}
Hash parseHash16or32(HashType ht, const string & s)
{
Hash hash(ht);
if (s.size() == hash.hashSize * 2)
/* hexadecimal representation */
hash = parseHash(ht, s);
else if (s.size() == hashLength32(hash))
/* base-32 representation */
hash = parseHash32(ht, s);
else
throw Error(format("hash `%1%' has wrong length for hash type `%2%'")
% s % printHashType(ht));
return hash;
}
bool isHash(const string & s)
{
if (s.length() != 32) return false;
for (int i = 0; i < 32; i++) {
char c = s[i];
if (!((c >= '0' && c <= '9') ||
(c >= 'a' && c <= 'f')))
return false;
}
return true;
}
/* The "hash context". */
struct Ctx
{
/* This copy constructor is needed in 'HashSink::currentHash()' where we
expect the copy of a 'Ctx' object to yield a truly different context. */
Ctx(Ctx &ref)
{
if (ref.md_handle == NULL)
md_handle = NULL;
else
gcry_md_copy (&md_handle, ref.md_handle);
}
/* Make sure 'md_handle' is always initialized. */
Ctx(): md_handle (NULL) { };
gcry_md_hd_t md_handle;
};
static void start(HashType ht, Ctx & ctx)
{
gcry_error_t err;
err = gcry_md_open (&ctx.md_handle, ht, 0);
assert (err == GPG_ERR_NO_ERROR);
}
static void update(HashType ht, Ctx & ctx,
const unsigned char * bytes, unsigned int len)
{
gcry_md_write (ctx.md_handle, bytes, len);
}
static void finish(HashType ht, Ctx & ctx, unsigned char * hash)
{
memcpy (hash, gcry_md_read (ctx.md_handle, ht),
gcry_md_get_algo_dlen (ht));
gcry_md_close (ctx.md_handle);
ctx.md_handle = NULL;
}
Hash hashString(HashType ht, const string & s)
{
Ctx ctx;
Hash hash(ht);
start(ht, ctx);
update(ht, ctx, (const unsigned char *) s.data(), s.length());
finish(ht, ctx, hash.hash);
return hash;
}
Hash hashFile(HashType ht, const Path & path)
{
Ctx ctx;
Hash hash(ht);
start(ht, ctx);
AutoCloseFD fd = open(path.c_str(), O_RDONLY);
if (fd == -1) throw SysError(format("opening file `%1%'") % path);
unsigned char buf[8192];
ssize_t n;
while ((n = read(fd, buf, sizeof(buf)))) {
checkInterrupt();
if (n == -1) throw SysError(format("reading file `%1%'") % path);
update(ht, ctx, buf, n);
}
finish(ht, ctx, hash.hash);
return hash;
}
HashSink::HashSink(HashType ht) : ht(ht)
{
ctx = new Ctx;
bytes = 0;
start(ht, *ctx);
}
HashSink::~HashSink()
{
bufPos = 0;
delete ctx;
}
void HashSink::write(const unsigned char * data, size_t len)
{
bytes += len;
update(ht, *ctx, data, len);
}
HashResult HashSink::finish()
{
flush();
Hash hash(ht);
nix::finish(ht, *ctx, hash.hash);
return HashResult(hash, bytes);
}
HashResult HashSink::currentHash()
{
flush();
Ctx ctx2 = *ctx;
Hash hash(ht);
nix::finish(ht, ctx2, hash.hash);
return HashResult(hash, bytes);
}
HashResult hashPath(
HashType ht, const Path & path, PathFilter & filter)
{
HashSink sink(ht);
dumpPath(path, sink, filter);
return sink.finish();
}
Hash compressHash(const Hash & hash, unsigned int newSize)
{
Hash h;
h.hashSize = newSize;
for (unsigned int i = 0; i < hash.hashSize; ++i)
h.hash[i % newSize] ^= hash.hash[i];
return h;
}
HashType parseHashType(const string & s)
{
if (s == "md5") return htMD5;
else if (s == "sha1") return htSHA1;
else if (s == "sha256") return htSHA256;
else if (s == "sha512") return htSHA512;
else if (s == "sha3-256") return htSHA3_256;
else if (s == "sha3-512") return htSHA3_512;
else if (s == "blake2s-256") return htBLAKE2s_256;
else return htUnknown;
}
string printHashType(HashType ht)
{
if (ht == htMD5) return "md5";
else if (ht == htSHA1) return "sha1";
else if (ht == htSHA256) return "sha256";
else if (ht == htSHA512) return "sha512";
else if (ht == htSHA3_256) return "sha3-256";
else if (ht == htSHA3_512) return "sha3-512";
else if (ht == htBLAKE2s_256) return "blake2s-256";
else throw Error("cannot print unknown hash type");
}
}