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Commit | Line | Data |
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0fcfd160 LT |
1 | /* |
2 | * GIT - The information manager from hell | |
3 | * | |
4 | * Copyright (C) Linus Torvalds, 2005 | |
5 | * | |
6 | * This handles basic git sha1 object files - packing, unpacking, | |
7 | * creation etc. | |
8 | */ | |
9 | #include <stdarg.h> | |
10 | #include "cache.h" | |
11 | ||
12 | const char *sha1_file_directory = NULL; | |
13 | ||
14 | static unsigned hexval(char c) | |
15 | { | |
16 | if (c >= '0' && c <= '9') | |
17 | return c - '0'; | |
18 | if (c >= 'a' && c <= 'f') | |
19 | return c - 'a' + 10; | |
20 | if (c >= 'A' && c <= 'F') | |
21 | return c - 'A' + 10; | |
22 | return ~0; | |
23 | } | |
24 | ||
25 | int get_sha1_hex(const char *hex, unsigned char *sha1) | |
26 | { | |
27 | int i; | |
28 | for (i = 0; i < 20; i++) { | |
29 | unsigned int val = (hexval(hex[0]) << 4) | hexval(hex[1]); | |
30 | if (val & ~0xff) | |
31 | return -1; | |
32 | *sha1++ = val; | |
33 | hex += 2; | |
34 | } | |
35 | return 0; | |
36 | } | |
37 | ||
38 | char * sha1_to_hex(const unsigned char *sha1) | |
39 | { | |
40 | static char buffer[50]; | |
41 | static const char hex[] = "0123456789abcdef"; | |
42 | char *buf = buffer; | |
43 | int i; | |
44 | ||
45 | for (i = 0; i < 20; i++) { | |
46 | unsigned int val = *sha1++; | |
47 | *buf++ = hex[val >> 4]; | |
48 | *buf++ = hex[val & 0xf]; | |
49 | } | |
50 | return buffer; | |
51 | } | |
52 | ||
53 | /* | |
54 | * NOTE! This returns a statically allocated buffer, so you have to be | |
55 | * careful about using it. Do a "strdup()" if you need to save the | |
56 | * filename. | |
57 | */ | |
58 | char *sha1_file_name(const unsigned char *sha1) | |
59 | { | |
60 | int i; | |
61 | static char *name, *base; | |
62 | ||
63 | if (!base) { | |
64 | char *sha1_file_directory = getenv(DB_ENVIRONMENT) ? : DEFAULT_DB_ENVIRONMENT; | |
65 | int len = strlen(sha1_file_directory); | |
66 | base = malloc(len + 60); | |
67 | memcpy(base, sha1_file_directory, len); | |
68 | memset(base+len, 0, 60); | |
69 | base[len] = '/'; | |
70 | base[len+3] = '/'; | |
71 | name = base + len + 1; | |
72 | } | |
73 | for (i = 0; i < 20; i++) { | |
74 | static char hex[] = "0123456789abcdef"; | |
75 | unsigned int val = sha1[i]; | |
76 | char *pos = name + i*2 + (i > 0); | |
77 | *pos++ = hex[val >> 4]; | |
78 | *pos = hex[val & 0xf]; | |
79 | } | |
80 | return base; | |
81 | } | |
82 | ||
d98b46f8 | 83 | int check_sha1_signature(unsigned char *sha1, void *map, unsigned long size, const char *type) |
0fcfd160 | 84 | { |
d98b46f8 | 85 | char header[100]; |
0fcfd160 LT |
86 | unsigned char real_sha1[20]; |
87 | SHA_CTX c; | |
88 | ||
89 | SHA1_Init(&c); | |
d98b46f8 | 90 | SHA1_Update(&c, header, 1+sprintf(header, "%s %lu", type, size)); |
0fcfd160 LT |
91 | SHA1_Update(&c, map, size); |
92 | SHA1_Final(real_sha1, &c); | |
93 | return memcmp(sha1, real_sha1, 20) ? -1 : 0; | |
94 | } | |
95 | ||
96 | void *map_sha1_file(const unsigned char *sha1, unsigned long *size) | |
97 | { | |
98 | char *filename = sha1_file_name(sha1); | |
99 | int fd = open(filename, O_RDONLY); | |
100 | struct stat st; | |
101 | void *map; | |
102 | ||
103 | if (fd < 0) { | |
104 | perror(filename); | |
105 | return NULL; | |
106 | } | |
107 | if (fstat(fd, &st) < 0) { | |
108 | close(fd); | |
109 | return NULL; | |
110 | } | |
111 | map = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0); | |
112 | close(fd); | |
113 | if (-1 == (int)(long)map) | |
114 | return NULL; | |
115 | *size = st.st_size; | |
116 | return map; | |
117 | } | |
118 | ||
119 | void * unpack_sha1_file(void *map, unsigned long mapsize, char *type, unsigned long *size) | |
120 | { | |
121 | int ret, bytes; | |
122 | z_stream stream; | |
123 | char buffer[8192]; | |
124 | char *buf; | |
125 | ||
126 | /* Get the data stream */ | |
127 | memset(&stream, 0, sizeof(stream)); | |
128 | stream.next_in = map; | |
129 | stream.avail_in = mapsize; | |
130 | stream.next_out = buffer; | |
131 | stream.avail_out = sizeof(buffer); | |
132 | ||
133 | inflateInit(&stream); | |
134 | ret = inflate(&stream, 0); | |
135 | if (sscanf(buffer, "%10s %lu", type, size) != 2) | |
136 | return NULL; | |
137 | ||
138 | bytes = strlen(buffer) + 1; | |
139 | buf = malloc(*size); | |
140 | if (!buf) | |
141 | return NULL; | |
142 | ||
143 | memcpy(buf, buffer + bytes, stream.total_out - bytes); | |
144 | bytes = stream.total_out - bytes; | |
145 | if (bytes < *size && ret == Z_OK) { | |
146 | stream.next_out = buf + bytes; | |
147 | stream.avail_out = *size - bytes; | |
148 | while (inflate(&stream, Z_FINISH) == Z_OK) | |
149 | /* nothing */; | |
150 | } | |
151 | inflateEnd(&stream); | |
152 | return buf; | |
153 | } | |
154 | ||
155 | void * read_sha1_file(const unsigned char *sha1, char *type, unsigned long *size) | |
156 | { | |
157 | unsigned long mapsize; | |
158 | void *map, *buf; | |
159 | ||
160 | map = map_sha1_file(sha1, &mapsize); | |
161 | if (map) { | |
162 | buf = unpack_sha1_file(map, mapsize, type, size); | |
163 | munmap(map, mapsize); | |
164 | return buf; | |
165 | } | |
166 | return NULL; | |
167 | } | |
168 | ||
f4913f91 JH |
169 | void *read_tree_with_tree_or_commit_sha1(const unsigned char *sha1, |
170 | unsigned long *size, | |
171 | unsigned char *tree_sha1_return) | |
172 | { | |
173 | char type[20]; | |
174 | void *buffer; | |
175 | unsigned long isize; | |
176 | int was_commit = 0; | |
860edf7a | 177 | unsigned char tree_sha1[20]; |
f4913f91 JH |
178 | |
179 | buffer = read_sha1_file(sha1, type, &isize); | |
180 | ||
181 | /* | |
182 | * We might have read a commit instead of a tree, in which case | |
183 | * we parse out the tree_sha1 and attempt to read from there. | |
184 | * (buffer + 5) is because the tree sha1 is always at offset 5 | |
185 | * in a commit record ("tree "). | |
186 | */ | |
187 | if (buffer && | |
188 | !strcmp(type, "commit") && | |
189 | !get_sha1_hex(buffer + 5, tree_sha1)) { | |
190 | free(buffer); | |
191 | buffer = read_sha1_file(tree_sha1, type, &isize); | |
192 | was_commit = 1; | |
193 | } | |
194 | ||
195 | /* | |
196 | * Now do we have something and if so is it a tree? | |
197 | */ | |
198 | if (!buffer || strcmp(type, "tree")) { | |
199 | free(buffer); | |
860edf7a | 200 | return NULL; |
f4913f91 JH |
201 | } |
202 | ||
203 | *size = isize; | |
204 | if (tree_sha1_return) | |
205 | memcpy(tree_sha1_return, was_commit ? tree_sha1 : sha1, 20); | |
206 | return buffer; | |
207 | } | |
208 | ||
0fcfd160 LT |
209 | int write_sha1_file(char *buf, unsigned len, unsigned char *returnsha1) |
210 | { | |
211 | int size; | |
212 | char *compressed; | |
213 | z_stream stream; | |
214 | unsigned char sha1[20]; | |
215 | SHA_CTX c; | |
706bc531 LT |
216 | char *filename; |
217 | int fd; | |
0fcfd160 | 218 | |
d98b46f8 LT |
219 | /* Sha1.. */ |
220 | SHA1_Init(&c); | |
221 | SHA1_Update(&c, buf, len); | |
222 | SHA1_Final(sha1, &c); | |
223 | ||
706bc531 LT |
224 | if (returnsha1) |
225 | memcpy(returnsha1, sha1, 20); | |
226 | ||
227 | filename = sha1_file_name(sha1); | |
228 | fd = open(filename, O_WRONLY | O_CREAT | O_EXCL, 0666); | |
229 | if (fd < 0) { | |
230 | if (errno != EEXIST) | |
231 | return -1; | |
232 | ||
233 | /* | |
234 | * We might do collision checking here, but we'd need to | |
235 | * uncompress the old file and check it. Later. | |
236 | */ | |
237 | return 0; | |
238 | } | |
239 | ||
0fcfd160 LT |
240 | /* Set it up */ |
241 | memset(&stream, 0, sizeof(stream)); | |
242 | deflateInit(&stream, Z_BEST_COMPRESSION); | |
243 | size = deflateBound(&stream, len); | |
244 | compressed = malloc(size); | |
245 | ||
246 | /* Compress it */ | |
247 | stream.next_in = buf; | |
248 | stream.avail_in = len; | |
249 | stream.next_out = compressed; | |
250 | stream.avail_out = size; | |
251 | while (deflate(&stream, Z_FINISH) == Z_OK) | |
252 | /* nothing */; | |
253 | deflateEnd(&stream); | |
254 | size = stream.total_out; | |
255 | ||
706bc531 LT |
256 | if (write(fd, compressed, size) != size) |
257 | die("unable to write file"); | |
258 | close(fd); | |
259 | ||
0fcfd160 LT |
260 | return 0; |
261 | } | |
262 | ||
263 | static inline int collision_check(char *filename, void *buf, unsigned int size) | |
264 | { | |
265 | #ifdef COLLISION_CHECK | |
266 | void *map; | |
267 | int fd = open(filename, O_RDONLY); | |
268 | struct stat st; | |
269 | int cmp; | |
270 | ||
271 | /* Unreadable object, or object went away? Strange. */ | |
272 | if (fd < 0) | |
273 | return -1; | |
274 | ||
275 | if (fstat(fd, &st) < 0 || size != st.st_size) | |
276 | return -1; | |
277 | ||
278 | map = mmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0); | |
279 | close(fd); | |
280 | if (map == MAP_FAILED) | |
281 | return -1; | |
282 | cmp = memcmp(buf, map, size); | |
283 | munmap(map, size); | |
284 | if (cmp) | |
285 | return -1; | |
286 | #endif | |
287 | return 0; | |
288 | } | |
289 | ||
290 | int write_sha1_buffer(const unsigned char *sha1, void *buf, unsigned int size) | |
291 | { | |
292 | char *filename = sha1_file_name(sha1); | |
293 | int fd; | |
294 | ||
295 | fd = open(filename, O_WRONLY | O_CREAT | O_EXCL, 0666); | |
296 | if (fd < 0) { | |
297 | if (errno != EEXIST) | |
298 | return -1; | |
299 | if (collision_check(filename, buf, size)) | |
300 | return error("SHA1 collision detected!" | |
301 | " This is bad, bad, BAD!\a\n"); | |
302 | return 0; | |
303 | } | |
304 | write(fd, buf, size); | |
305 | close(fd); | |
306 | return 0; | |
307 | } |