| #ifndef HASH_H |
| #define HASH_H |
| |
| #include "git-compat-util.h" |
| #include "repository.h" |
| |
| #if defined(SHA1_PPC) |
| #include "ppc/sha1.h" |
| #elif defined(SHA1_APPLE) |
| #include <CommonCrypto/CommonDigest.h> |
| #elif defined(SHA1_OPENSSL) |
| #include <openssl/sha.h> |
| #elif defined(SHA1_DC) |
| #include "sha1dc_git.h" |
| #else /* SHA1_BLK */ |
| #include "block-sha1/sha1.h" |
| #endif |
| |
| #if defined(SHA256_GCRYPT) |
| #define SHA256_NEEDS_CLONE_HELPER |
| #include "sha256/gcrypt.h" |
| #elif defined(SHA256_OPENSSL) |
| #include <openssl/sha.h> |
| #else |
| #include "sha256/block/sha256.h" |
| #endif |
| |
| #ifndef platform_SHA_CTX |
| /* |
| * platform's underlying implementation of SHA-1; could be OpenSSL, |
| * blk_SHA, Apple CommonCrypto, etc... Note that the relevant |
| * SHA-1 header may have already defined platform_SHA_CTX for our |
| * own implementations like block-sha1 and ppc-sha1, so we list |
| * the default for OpenSSL compatible SHA-1 implementations here. |
| */ |
| #define platform_SHA_CTX SHA_CTX |
| #define platform_SHA1_Init SHA1_Init |
| #define platform_SHA1_Update SHA1_Update |
| #define platform_SHA1_Final SHA1_Final |
| #endif |
| |
| #define git_SHA_CTX platform_SHA_CTX |
| #define git_SHA1_Init platform_SHA1_Init |
| #define git_SHA1_Update platform_SHA1_Update |
| #define git_SHA1_Final platform_SHA1_Final |
| |
| #ifndef platform_SHA256_CTX |
| #define platform_SHA256_CTX SHA256_CTX |
| #define platform_SHA256_Init SHA256_Init |
| #define platform_SHA256_Update SHA256_Update |
| #define platform_SHA256_Final SHA256_Final |
| #endif |
| |
| #define git_SHA256_CTX platform_SHA256_CTX |
| #define git_SHA256_Init platform_SHA256_Init |
| #define git_SHA256_Update platform_SHA256_Update |
| #define git_SHA256_Final platform_SHA256_Final |
| |
| #ifdef platform_SHA256_Clone |
| #define git_SHA256_Clone platform_SHA256_Clone |
| #endif |
| |
| #ifdef SHA1_MAX_BLOCK_SIZE |
| #include "compat/sha1-chunked.h" |
| #undef git_SHA1_Update |
| #define git_SHA1_Update git_SHA1_Update_Chunked |
| #endif |
| |
| static inline void git_SHA1_Clone(git_SHA_CTX *dst, const git_SHA_CTX *src) |
| { |
| memcpy(dst, src, sizeof(*dst)); |
| } |
| |
| #ifndef SHA256_NEEDS_CLONE_HELPER |
| static inline void git_SHA256_Clone(git_SHA256_CTX *dst, const git_SHA256_CTX *src) |
| { |
| memcpy(dst, src, sizeof(*dst)); |
| } |
| #endif |
| |
| /* |
| * Note that these constants are suitable for indexing the hash_algos array and |
| * comparing against each other, but are otherwise arbitrary, so they should not |
| * be exposed to the user or serialized to disk. To know whether a |
| * git_hash_algo struct points to some usable hash function, test the format_id |
| * field for being non-zero. Use the name field for user-visible situations and |
| * the format_id field for fixed-length fields on disk. |
| */ |
| /* An unknown hash function. */ |
| #define GIT_HASH_UNKNOWN 0 |
| /* SHA-1 */ |
| #define GIT_HASH_SHA1 1 |
| /* SHA-256 */ |
| #define GIT_HASH_SHA256 2 |
| /* Number of algorithms supported (including unknown). */ |
| #define GIT_HASH_NALGOS (GIT_HASH_SHA256 + 1) |
| |
| /* The length in bytes and in hex digits of an object name (SHA-1 value). */ |
| #define GIT_SHA1_RAWSZ 20 |
| #define GIT_SHA1_HEXSZ (2 * GIT_SHA1_RAWSZ) |
| /* The block size of SHA-1. */ |
| #define GIT_SHA1_BLKSZ 64 |
| |
| /* The length in bytes and in hex digits of an object name (SHA-256 value). */ |
| #define GIT_SHA256_RAWSZ 32 |
| #define GIT_SHA256_HEXSZ (2 * GIT_SHA256_RAWSZ) |
| /* The block size of SHA-256. */ |
| #define GIT_SHA256_BLKSZ 64 |
| |
| /* The length in byte and in hex digits of the largest possible hash value. */ |
| #define GIT_MAX_RAWSZ GIT_SHA256_RAWSZ |
| #define GIT_MAX_HEXSZ GIT_SHA256_HEXSZ |
| /* The largest possible block size for any supported hash. */ |
| #define GIT_MAX_BLKSZ GIT_SHA256_BLKSZ |
| |
| struct object_id { |
| unsigned char hash[GIT_MAX_RAWSZ]; |
| int algo; /* XXX requires 4-byte alignment */ |
| }; |
| |
| /* A suitably aligned type for stack allocations of hash contexts. */ |
| union git_hash_ctx { |
| git_SHA_CTX sha1; |
| git_SHA256_CTX sha256; |
| }; |
| typedef union git_hash_ctx git_hash_ctx; |
| |
| typedef void (*git_hash_init_fn)(git_hash_ctx *ctx); |
| typedef void (*git_hash_clone_fn)(git_hash_ctx *dst, const git_hash_ctx *src); |
| typedef void (*git_hash_update_fn)(git_hash_ctx *ctx, const void *in, size_t len); |
| typedef void (*git_hash_final_fn)(unsigned char *hash, git_hash_ctx *ctx); |
| typedef void (*git_hash_final_oid_fn)(struct object_id *oid, git_hash_ctx *ctx); |
| |
| struct git_hash_algo { |
| /* |
| * The name of the algorithm, as appears in the config file and in |
| * messages. |
| */ |
| const char *name; |
| |
| /* A four-byte version identifier, used in pack indices. */ |
| uint32_t format_id; |
| |
| /* The length of the hash in binary. */ |
| size_t rawsz; |
| |
| /* The length of the hash in hex characters. */ |
| size_t hexsz; |
| |
| /* The block size of the hash. */ |
| size_t blksz; |
| |
| /* The hash initialization function. */ |
| git_hash_init_fn init_fn; |
| |
| /* The hash context cloning function. */ |
| git_hash_clone_fn clone_fn; |
| |
| /* The hash update function. */ |
| git_hash_update_fn update_fn; |
| |
| /* The hash finalization function. */ |
| git_hash_final_fn final_fn; |
| |
| /* The hash finalization function for object IDs. */ |
| git_hash_final_oid_fn final_oid_fn; |
| |
| /* The OID of the empty tree. */ |
| const struct object_id *empty_tree; |
| |
| /* The OID of the empty blob. */ |
| const struct object_id *empty_blob; |
| |
| /* The all-zeros OID. */ |
| const struct object_id *null_oid; |
| }; |
| extern const struct git_hash_algo hash_algos[GIT_HASH_NALGOS]; |
| |
| /* |
| * Return a GIT_HASH_* constant based on the name. Returns GIT_HASH_UNKNOWN if |
| * the name doesn't match a known algorithm. |
| */ |
| int hash_algo_by_name(const char *name); |
| /* Identical, except based on the format ID. */ |
| int hash_algo_by_id(uint32_t format_id); |
| /* Identical, except based on the length. */ |
| int hash_algo_by_length(int len); |
| /* Identical, except for a pointer to struct git_hash_algo. */ |
| static inline int hash_algo_by_ptr(const struct git_hash_algo *p) |
| { |
| return p - hash_algos; |
| } |
| |
| #define the_hash_algo the_repository->hash_algo |
| |
| const struct object_id *null_oid(void); |
| |
| static inline int hashcmp_algop(const unsigned char *sha1, const unsigned char *sha2, const struct git_hash_algo *algop) |
| { |
| /* |
| * Teach the compiler that there are only two possibilities of hash size |
| * here, so that it can optimize for this case as much as possible. |
| */ |
| if (algop->rawsz == GIT_MAX_RAWSZ) |
| return memcmp(sha1, sha2, GIT_MAX_RAWSZ); |
| return memcmp(sha1, sha2, GIT_SHA1_RAWSZ); |
| } |
| |
| static inline int hashcmp(const unsigned char *sha1, const unsigned char *sha2) |
| { |
| return hashcmp_algop(sha1, sha2, the_hash_algo); |
| } |
| |
| static inline int oidcmp(const struct object_id *oid1, const struct object_id *oid2) |
| { |
| const struct git_hash_algo *algop; |
| if (!oid1->algo) |
| algop = the_hash_algo; |
| else |
| algop = &hash_algos[oid1->algo]; |
| return hashcmp_algop(oid1->hash, oid2->hash, algop); |
| } |
| |
| static inline int hasheq_algop(const unsigned char *sha1, const unsigned char *sha2, const struct git_hash_algo *algop) |
| { |
| /* |
| * We write this here instead of deferring to hashcmp so that the |
| * compiler can properly inline it and avoid calling memcmp. |
| */ |
| if (algop->rawsz == GIT_MAX_RAWSZ) |
| return !memcmp(sha1, sha2, GIT_MAX_RAWSZ); |
| return !memcmp(sha1, sha2, GIT_SHA1_RAWSZ); |
| } |
| |
| static inline int hasheq(const unsigned char *sha1, const unsigned char *sha2) |
| { |
| return hasheq_algop(sha1, sha2, the_hash_algo); |
| } |
| |
| static inline int oideq(const struct object_id *oid1, const struct object_id *oid2) |
| { |
| const struct git_hash_algo *algop; |
| if (!oid1->algo) |
| algop = the_hash_algo; |
| else |
| algop = &hash_algos[oid1->algo]; |
| return hasheq_algop(oid1->hash, oid2->hash, algop); |
| } |
| |
| static inline int is_null_oid(const struct object_id *oid) |
| { |
| return oideq(oid, null_oid()); |
| } |
| |
| static inline void hashcpy(unsigned char *sha_dst, const unsigned char *sha_src) |
| { |
| memcpy(sha_dst, sha_src, the_hash_algo->rawsz); |
| } |
| |
| static inline void oidcpy(struct object_id *dst, const struct object_id *src) |
| { |
| memcpy(dst->hash, src->hash, GIT_MAX_RAWSZ); |
| dst->algo = src->algo; |
| } |
| |
| /* Like oidcpy() but zero-pads the unused bytes in dst's hash array. */ |
| static inline void oidcpy_with_padding(struct object_id *dst, |
| const struct object_id *src) |
| { |
| size_t hashsz; |
| |
| if (!src->algo) |
| hashsz = the_hash_algo->rawsz; |
| else |
| hashsz = hash_algos[src->algo].rawsz; |
| |
| memcpy(dst->hash, src->hash, hashsz); |
| memset(dst->hash + hashsz, 0, GIT_MAX_RAWSZ - hashsz); |
| dst->algo = src->algo; |
| } |
| |
| static inline struct object_id *oiddup(const struct object_id *src) |
| { |
| struct object_id *dst = xmalloc(sizeof(struct object_id)); |
| oidcpy(dst, src); |
| return dst; |
| } |
| |
| static inline void hashclr(unsigned char *hash) |
| { |
| memset(hash, 0, the_hash_algo->rawsz); |
| } |
| |
| static inline void oidclr(struct object_id *oid) |
| { |
| memset(oid->hash, 0, GIT_MAX_RAWSZ); |
| oid->algo = hash_algo_by_ptr(the_hash_algo); |
| } |
| |
| static inline void oidread(struct object_id *oid, const unsigned char *hash) |
| { |
| memcpy(oid->hash, hash, the_hash_algo->rawsz); |
| oid->algo = hash_algo_by_ptr(the_hash_algo); |
| } |
| |
| static inline int is_empty_blob_sha1(const unsigned char *sha1) |
| { |
| return hasheq(sha1, the_hash_algo->empty_blob->hash); |
| } |
| |
| static inline int is_empty_blob_oid(const struct object_id *oid) |
| { |
| return oideq(oid, the_hash_algo->empty_blob); |
| } |
| |
| static inline int is_empty_tree_sha1(const unsigned char *sha1) |
| { |
| return hasheq(sha1, the_hash_algo->empty_tree->hash); |
| } |
| |
| static inline int is_empty_tree_oid(const struct object_id *oid) |
| { |
| return oideq(oid, the_hash_algo->empty_tree); |
| } |
| |
| static inline void oid_set_algo(struct object_id *oid, const struct git_hash_algo *algop) |
| { |
| oid->algo = hash_algo_by_ptr(algop); |
| } |
| |
| const char *empty_tree_oid_hex(void); |
| const char *empty_blob_oid_hex(void); |
| |
| #endif |