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-rw-r--r--nix/libutil/hash.cc382
1 files changed, 382 insertions, 0 deletions
diff --git a/nix/libutil/hash.cc b/nix/libutil/hash.cc
new file mode 100644
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--- /dev/null
+++ b/nix/libutil/hash.cc
@@ -0,0 +1,382 @@
+#include "config.h"
+
+#include <iostream>
+#include <cstring>
+
+#ifdef HAVE_OPENSSL
+#include <openssl/md5.h>
+#include <openssl/sha.h>
+#else
+extern "C" {
+#include "md5.h"
+#include "sha1.h"
+#include "sha256.h"
+}
+#endif
+
+#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;
+ if (type == htMD5) hashSize = md5HashSize;
+ else if (type == htSHA1) hashSize = sha1HashSize;
+ else if (type == htSHA256) hashSize = sha256HashSize;
+ else 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;
+}
+
+
+static unsigned char divMod(unsigned char * bytes, unsigned char y)
+{
+ unsigned int borrow = 0;
+
+ int pos = Hash::maxHashSize - 1;
+ while (pos >= 0 && !bytes[pos]) --pos;
+
+ for ( ; pos >= 0; --pos) {
+ unsigned int s = bytes[pos] + (borrow << 8);
+ unsigned int d = s / y;
+ borrow = s % y;
+ bytes[pos] = d;
+ }
+
+ return borrow;
+}
+
+
+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);
+
+ const char * chars = base32Chars.data();
+
+ string s(len, '0');
+
+ int pos = len - 1;
+ while (pos >= 0) {
+ unsigned char digit = divMod(hash2.hash, 32);
+ s[pos--] = chars[digit];
+ }
+
+ for (unsigned int i = 0; i < hash2.maxHashSize; ++i)
+ assert(hash2.hash[i] == 0);
+
+ return s;
+}
+
+
+string printHash16or32(const Hash & hash)
+{
+ return hash.type == htMD5 ? printHash(hash) : printHash32(hash);
+}
+
+
+static bool mul(unsigned char * bytes, unsigned char y, int maxSize)
+{
+ unsigned char carry = 0;
+
+ for (int pos = 0; pos < maxSize; ++pos) {
+ unsigned int m = bytes[pos] * y + carry;
+ bytes[pos] = m & 0xff;
+ carry = m >> 8;
+ }
+
+ return carry;
+}
+
+
+static bool add(unsigned char * bytes, unsigned char y, int maxSize)
+{
+ unsigned char carry = y;
+
+ for (int pos = 0; pos < maxSize; ++pos) {
+ unsigned int m = bytes[pos] + carry;
+ bytes[pos] = m & 0xff;
+ carry = m >> 8;
+ if (carry == 0) break;
+ }
+
+ return carry;
+}
+
+
+Hash parseHash32(HashType ht, const string & s)
+{
+ Hash hash(ht);
+
+ const char * chars = base32Chars.data();
+
+ for (unsigned int i = 0; i < s.length(); ++i) {
+ char c = s[i];
+ unsigned char digit;
+ for (digit = 0; digit < base32Chars.size(); ++digit) /* !!! slow */
+ if (chars[digit] == c) break;
+ if (digit >= 32)
+ throw Error(format("invalid base-32 hash `%1%'") % s);
+ if (mul(hash.hash, 32, hash.hashSize) ||
+ add(hash.hash, digit, hash.hashSize))
+ throw Error(format("base-32 hash `%1%' is too large") % s);
+ }
+
+ 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;
+}
+
+
+struct Ctx
+{
+ MD5_CTX md5;
+ SHA_CTX sha1;
+ SHA256_CTX sha256;
+};
+
+
+static void start(HashType ht, Ctx & ctx)
+{
+ if (ht == htMD5) MD5_Init(&ctx.md5);
+ else if (ht == htSHA1) SHA1_Init(&ctx.sha1);
+ else if (ht == htSHA256) SHA256_Init(&ctx.sha256);
+}
+
+
+static void update(HashType ht, Ctx & ctx,
+ const unsigned char * bytes, unsigned int len)
+{
+ if (ht == htMD5) MD5_Update(&ctx.md5, bytes, len);
+ else if (ht == htSHA1) SHA1_Update(&ctx.sha1, bytes, len);
+ else if (ht == htSHA256) SHA256_Update(&ctx.sha256, bytes, len);
+}
+
+
+static void finish(HashType ht, Ctx & ctx, unsigned char * hash)
+{
+ if (ht == htMD5) MD5_Final(hash, &ctx.md5);
+ else if (ht == htSHA1) SHA1_Final(hash, &ctx.sha1);
+ else if (ht == htSHA256) SHA256_Final(hash, &ctx.sha256);
+}
+
+
+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 return htUnknown;
+}
+
+
+string printHashType(HashType ht)
+{
+ if (ht == htMD5) return "md5";
+ else if (ht == htSHA1) return "sha1";
+ else if (ht == htSHA256) return "sha256";
+ else throw Error("cannot print unknown hash type");
+}
+
+
+}