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d1cbe1e6 EN |
1 | #ifndef HASH_LL_H |
2 | #define HASH_LL_H | |
3 | ||
4 | #if defined(SHA1_APPLE) | |
5 | #include <CommonCrypto/CommonDigest.h> | |
6 | #elif defined(SHA1_OPENSSL) | |
bda9c120 EW |
7 | # include <openssl/sha.h> |
8 | # if defined(OPENSSL_API_LEVEL) && OPENSSL_API_LEVEL >= 3 | |
9 | # define SHA1_NEEDS_CLONE_HELPER | |
10 | # include "sha1/openssl.h" | |
11 | # endif | |
d1cbe1e6 EN |
12 | #elif defined(SHA1_DC) |
13 | #include "sha1dc_git.h" | |
14 | #else /* SHA1_BLK */ | |
15 | #include "block-sha1/sha1.h" | |
16 | #endif | |
17 | ||
18 | #if defined(SHA256_NETTLE) | |
19 | #include "sha256/nettle.h" | |
20 | #elif defined(SHA256_GCRYPT) | |
21 | #define SHA256_NEEDS_CLONE_HELPER | |
22 | #include "sha256/gcrypt.h" | |
23 | #elif defined(SHA256_OPENSSL) | |
3e440ea0 EW |
24 | # include <openssl/sha.h> |
25 | # if defined(OPENSSL_API_LEVEL) && OPENSSL_API_LEVEL >= 3 | |
26 | # define SHA256_NEEDS_CLONE_HELPER | |
27 | # include "sha256/openssl.h" | |
28 | # endif | |
d1cbe1e6 EN |
29 | #else |
30 | #include "sha256/block/sha256.h" | |
31 | #endif | |
32 | ||
33 | #ifndef platform_SHA_CTX | |
34 | /* | |
35 | * platform's underlying implementation of SHA-1; could be OpenSSL, | |
36 | * blk_SHA, Apple CommonCrypto, etc... Note that the relevant | |
37 | * SHA-1 header may have already defined platform_SHA_CTX for our | |
38 | * own implementations like block-sha1, so we list | |
39 | * the default for OpenSSL compatible SHA-1 implementations here. | |
40 | */ | |
41 | #define platform_SHA_CTX SHA_CTX | |
42 | #define platform_SHA1_Init SHA1_Init | |
43 | #define platform_SHA1_Update SHA1_Update | |
44 | #define platform_SHA1_Final SHA1_Final | |
45 | #endif | |
46 | ||
47 | #define git_SHA_CTX platform_SHA_CTX | |
48 | #define git_SHA1_Init platform_SHA1_Init | |
49 | #define git_SHA1_Update platform_SHA1_Update | |
50 | #define git_SHA1_Final platform_SHA1_Final | |
51 | ||
bda9c120 EW |
52 | #ifdef platform_SHA1_Clone |
53 | #define git_SHA1_Clone platform_SHA1_Clone | |
54 | #endif | |
55 | ||
d1cbe1e6 EN |
56 | #ifndef platform_SHA256_CTX |
57 | #define platform_SHA256_CTX SHA256_CTX | |
58 | #define platform_SHA256_Init SHA256_Init | |
59 | #define platform_SHA256_Update SHA256_Update | |
60 | #define platform_SHA256_Final SHA256_Final | |
61 | #endif | |
62 | ||
63 | #define git_SHA256_CTX platform_SHA256_CTX | |
64 | #define git_SHA256_Init platform_SHA256_Init | |
65 | #define git_SHA256_Update platform_SHA256_Update | |
66 | #define git_SHA256_Final platform_SHA256_Final | |
67 | ||
68 | #ifdef platform_SHA256_Clone | |
69 | #define git_SHA256_Clone platform_SHA256_Clone | |
70 | #endif | |
71 | ||
72 | #ifdef SHA1_MAX_BLOCK_SIZE | |
73 | #include "compat/sha1-chunked.h" | |
74 | #undef git_SHA1_Update | |
75 | #define git_SHA1_Update git_SHA1_Update_Chunked | |
76 | #endif | |
77 | ||
bda9c120 | 78 | #ifndef SHA1_NEEDS_CLONE_HELPER |
d1cbe1e6 EN |
79 | static inline void git_SHA1_Clone(git_SHA_CTX *dst, const git_SHA_CTX *src) |
80 | { | |
81 | memcpy(dst, src, sizeof(*dst)); | |
82 | } | |
bda9c120 | 83 | #endif |
d1cbe1e6 EN |
84 | |
85 | #ifndef SHA256_NEEDS_CLONE_HELPER | |
86 | static inline void git_SHA256_Clone(git_SHA256_CTX *dst, const git_SHA256_CTX *src) | |
87 | { | |
88 | memcpy(dst, src, sizeof(*dst)); | |
89 | } | |
90 | #endif | |
91 | ||
92 | /* | |
93 | * Note that these constants are suitable for indexing the hash_algos array and | |
94 | * comparing against each other, but are otherwise arbitrary, so they should not | |
95 | * be exposed to the user or serialized to disk. To know whether a | |
96 | * git_hash_algo struct points to some usable hash function, test the format_id | |
97 | * field for being non-zero. Use the name field for user-visible situations and | |
98 | * the format_id field for fixed-length fields on disk. | |
99 | */ | |
100 | /* An unknown hash function. */ | |
101 | #define GIT_HASH_UNKNOWN 0 | |
102 | /* SHA-1 */ | |
103 | #define GIT_HASH_SHA1 1 | |
104 | /* SHA-256 */ | |
105 | #define GIT_HASH_SHA256 2 | |
106 | /* Number of algorithms supported (including unknown). */ | |
107 | #define GIT_HASH_NALGOS (GIT_HASH_SHA256 + 1) | |
108 | ||
109 | /* "sha1", big-endian */ | |
110 | #define GIT_SHA1_FORMAT_ID 0x73686131 | |
111 | ||
112 | /* The length in bytes and in hex digits of an object name (SHA-1 value). */ | |
113 | #define GIT_SHA1_RAWSZ 20 | |
114 | #define GIT_SHA1_HEXSZ (2 * GIT_SHA1_RAWSZ) | |
115 | /* The block size of SHA-1. */ | |
116 | #define GIT_SHA1_BLKSZ 64 | |
117 | ||
118 | /* "s256", big-endian */ | |
119 | #define GIT_SHA256_FORMAT_ID 0x73323536 | |
120 | ||
121 | /* The length in bytes and in hex digits of an object name (SHA-256 value). */ | |
122 | #define GIT_SHA256_RAWSZ 32 | |
123 | #define GIT_SHA256_HEXSZ (2 * GIT_SHA256_RAWSZ) | |
124 | /* The block size of SHA-256. */ | |
125 | #define GIT_SHA256_BLKSZ 64 | |
126 | ||
127 | /* The length in byte and in hex digits of the largest possible hash value. */ | |
128 | #define GIT_MAX_RAWSZ GIT_SHA256_RAWSZ | |
129 | #define GIT_MAX_HEXSZ GIT_SHA256_HEXSZ | |
130 | /* The largest possible block size for any supported hash. */ | |
131 | #define GIT_MAX_BLKSZ GIT_SHA256_BLKSZ | |
132 | ||
133 | struct object_id { | |
134 | unsigned char hash[GIT_MAX_RAWSZ]; | |
135 | int algo; /* XXX requires 4-byte alignment */ | |
136 | }; | |
137 | ||
138 | #define GET_OID_QUIETLY 01 | |
139 | #define GET_OID_COMMIT 02 | |
140 | #define GET_OID_COMMITTISH 04 | |
141 | #define GET_OID_TREE 010 | |
142 | #define GET_OID_TREEISH 020 | |
143 | #define GET_OID_BLOB 040 | |
144 | #define GET_OID_FOLLOW_SYMLINKS 0100 | |
145 | #define GET_OID_RECORD_PATH 0200 | |
146 | #define GET_OID_ONLY_TO_DIE 04000 | |
147 | #define GET_OID_REQUIRE_PATH 010000 | |
148 | ||
149 | #define GET_OID_DISAMBIGUATORS \ | |
150 | (GET_OID_COMMIT | GET_OID_COMMITTISH | \ | |
151 | GET_OID_TREE | GET_OID_TREEISH | \ | |
152 | GET_OID_BLOB) | |
153 | ||
154 | enum get_oid_result { | |
155 | FOUND = 0, | |
156 | MISSING_OBJECT = -1, /* The requested object is missing */ | |
157 | SHORT_NAME_AMBIGUOUS = -2, | |
158 | /* The following only apply when symlinks are followed */ | |
159 | DANGLING_SYMLINK = -4, /* | |
160 | * The initial symlink is there, but | |
161 | * (transitively) points to a missing | |
162 | * in-tree file | |
163 | */ | |
164 | SYMLINK_LOOP = -5, | |
165 | NOT_DIR = -6, /* | |
166 | * Somewhere along the symlink chain, a path is | |
167 | * requested which contains a file as a | |
168 | * non-final element. | |
169 | */ | |
170 | }; | |
171 | ||
172 | /* A suitably aligned type for stack allocations of hash contexts. */ | |
173 | union git_hash_ctx { | |
174 | git_SHA_CTX sha1; | |
175 | git_SHA256_CTX sha256; | |
176 | }; | |
177 | typedef union git_hash_ctx git_hash_ctx; | |
178 | ||
179 | typedef void (*git_hash_init_fn)(git_hash_ctx *ctx); | |
180 | typedef void (*git_hash_clone_fn)(git_hash_ctx *dst, const git_hash_ctx *src); | |
181 | typedef void (*git_hash_update_fn)(git_hash_ctx *ctx, const void *in, size_t len); | |
182 | typedef void (*git_hash_final_fn)(unsigned char *hash, git_hash_ctx *ctx); | |
183 | typedef void (*git_hash_final_oid_fn)(struct object_id *oid, git_hash_ctx *ctx); | |
184 | ||
185 | struct git_hash_algo { | |
186 | /* | |
187 | * The name of the algorithm, as appears in the config file and in | |
188 | * messages. | |
189 | */ | |
190 | const char *name; | |
191 | ||
192 | /* A four-byte version identifier, used in pack indices. */ | |
193 | uint32_t format_id; | |
194 | ||
195 | /* The length of the hash in binary. */ | |
196 | size_t rawsz; | |
197 | ||
198 | /* The length of the hash in hex characters. */ | |
199 | size_t hexsz; | |
200 | ||
201 | /* The block size of the hash. */ | |
202 | size_t blksz; | |
203 | ||
204 | /* The hash initialization function. */ | |
205 | git_hash_init_fn init_fn; | |
206 | ||
207 | /* The hash context cloning function. */ | |
208 | git_hash_clone_fn clone_fn; | |
209 | ||
210 | /* The hash update function. */ | |
211 | git_hash_update_fn update_fn; | |
212 | ||
213 | /* The hash finalization function. */ | |
214 | git_hash_final_fn final_fn; | |
215 | ||
216 | /* The hash finalization function for object IDs. */ | |
217 | git_hash_final_oid_fn final_oid_fn; | |
218 | ||
219 | /* The OID of the empty tree. */ | |
220 | const struct object_id *empty_tree; | |
221 | ||
222 | /* The OID of the empty blob. */ | |
223 | const struct object_id *empty_blob; | |
224 | ||
225 | /* The all-zeros OID. */ | |
226 | const struct object_id *null_oid; | |
227 | }; | |
228 | extern const struct git_hash_algo hash_algos[GIT_HASH_NALGOS]; | |
229 | ||
230 | /* | |
231 | * Return a GIT_HASH_* constant based on the name. Returns GIT_HASH_UNKNOWN if | |
232 | * the name doesn't match a known algorithm. | |
233 | */ | |
234 | int hash_algo_by_name(const char *name); | |
235 | /* Identical, except based on the format ID. */ | |
236 | int hash_algo_by_id(uint32_t format_id); | |
237 | /* Identical, except based on the length. */ | |
238 | int hash_algo_by_length(int len); | |
239 | /* Identical, except for a pointer to struct git_hash_algo. */ | |
240 | static inline int hash_algo_by_ptr(const struct git_hash_algo *p) | |
241 | { | |
242 | return p - hash_algos; | |
243 | } | |
244 | ||
245 | const struct object_id *null_oid(void); | |
246 | ||
247 | static inline int hashcmp_algop(const unsigned char *sha1, const unsigned char *sha2, const struct git_hash_algo *algop) | |
248 | { | |
249 | /* | |
250 | * Teach the compiler that there are only two possibilities of hash size | |
251 | * here, so that it can optimize for this case as much as possible. | |
252 | */ | |
253 | if (algop->rawsz == GIT_MAX_RAWSZ) | |
254 | return memcmp(sha1, sha2, GIT_MAX_RAWSZ); | |
255 | return memcmp(sha1, sha2, GIT_SHA1_RAWSZ); | |
256 | } | |
257 | ||
258 | static inline int hasheq_algop(const unsigned char *sha1, const unsigned char *sha2, const struct git_hash_algo *algop) | |
259 | { | |
260 | /* | |
261 | * We write this here instead of deferring to hashcmp so that the | |
262 | * compiler can properly inline it and avoid calling memcmp. | |
263 | */ | |
264 | if (algop->rawsz == GIT_MAX_RAWSZ) | |
265 | return !memcmp(sha1, sha2, GIT_MAX_RAWSZ); | |
266 | return !memcmp(sha1, sha2, GIT_SHA1_RAWSZ); | |
267 | } | |
268 | ||
269 | static inline void oidcpy(struct object_id *dst, const struct object_id *src) | |
270 | { | |
271 | memcpy(dst->hash, src->hash, GIT_MAX_RAWSZ); | |
272 | dst->algo = src->algo; | |
273 | } | |
274 | ||
275 | static inline struct object_id *oiddup(const struct object_id *src) | |
276 | { | |
277 | struct object_id *dst = xmalloc(sizeof(struct object_id)); | |
278 | oidcpy(dst, src); | |
279 | return dst; | |
280 | } | |
281 | ||
282 | static inline void oid_set_algo(struct object_id *oid, const struct git_hash_algo *algop) | |
283 | { | |
284 | oid->algo = hash_algo_by_ptr(algop); | |
285 | } | |
286 | ||
b9a7ac2c EN |
287 | /* |
288 | * Converts a cryptographic hash (e.g. SHA-1) into an int-sized hash code | |
289 | * for use in hash tables. Cryptographic hashes are supposed to have | |
290 | * uniform distribution, so in contrast to `memhash()`, this just copies | |
291 | * the first `sizeof(int)` bytes without shuffling any bits. Note that | |
292 | * the results will be different on big-endian and little-endian | |
293 | * platforms, so they should not be stored or transferred over the net. | |
294 | */ | |
295 | static inline unsigned int oidhash(const struct object_id *oid) | |
296 | { | |
297 | /* | |
298 | * Equivalent to 'return *(unsigned int *)oid->hash;', but safe on | |
299 | * platforms that don't support unaligned reads. | |
300 | */ | |
301 | unsigned int hash; | |
302 | memcpy(&hash, oid->hash, sizeof(hash)); | |
303 | return hash; | |
304 | } | |
305 | ||
d1cbe1e6 EN |
306 | const char *empty_tree_oid_hex(void); |
307 | const char *empty_blob_oid_hex(void); | |
308 | ||
309 | #endif |