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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 | ||
83 | int check_sha1_signature(unsigned char *sha1, void *map, unsigned long size) | |
84 | { | |
85 | unsigned char real_sha1[20]; | |
86 | SHA_CTX c; | |
87 | ||
88 | SHA1_Init(&c); | |
89 | SHA1_Update(&c, map, size); | |
90 | SHA1_Final(real_sha1, &c); | |
91 | return memcmp(sha1, real_sha1, 20) ? -1 : 0; | |
92 | } | |
93 | ||
94 | void *map_sha1_file(const unsigned char *sha1, unsigned long *size) | |
95 | { | |
96 | char *filename = sha1_file_name(sha1); | |
97 | int fd = open(filename, O_RDONLY); | |
98 | struct stat st; | |
99 | void *map; | |
100 | ||
101 | if (fd < 0) { | |
102 | perror(filename); | |
103 | return NULL; | |
104 | } | |
105 | if (fstat(fd, &st) < 0) { | |
106 | close(fd); | |
107 | return NULL; | |
108 | } | |
109 | map = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0); | |
110 | close(fd); | |
111 | if (-1 == (int)(long)map) | |
112 | return NULL; | |
113 | *size = st.st_size; | |
114 | return map; | |
115 | } | |
116 | ||
117 | void * unpack_sha1_file(void *map, unsigned long mapsize, char *type, unsigned long *size) | |
118 | { | |
119 | int ret, bytes; | |
120 | z_stream stream; | |
121 | char buffer[8192]; | |
122 | char *buf; | |
123 | ||
124 | /* Get the data stream */ | |
125 | memset(&stream, 0, sizeof(stream)); | |
126 | stream.next_in = map; | |
127 | stream.avail_in = mapsize; | |
128 | stream.next_out = buffer; | |
129 | stream.avail_out = sizeof(buffer); | |
130 | ||
131 | inflateInit(&stream); | |
132 | ret = inflate(&stream, 0); | |
133 | if (sscanf(buffer, "%10s %lu", type, size) != 2) | |
134 | return NULL; | |
135 | ||
136 | bytes = strlen(buffer) + 1; | |
137 | buf = malloc(*size); | |
138 | if (!buf) | |
139 | return NULL; | |
140 | ||
141 | memcpy(buf, buffer + bytes, stream.total_out - bytes); | |
142 | bytes = stream.total_out - bytes; | |
143 | if (bytes < *size && ret == Z_OK) { | |
144 | stream.next_out = buf + bytes; | |
145 | stream.avail_out = *size - bytes; | |
146 | while (inflate(&stream, Z_FINISH) == Z_OK) | |
147 | /* nothing */; | |
148 | } | |
149 | inflateEnd(&stream); | |
150 | return buf; | |
151 | } | |
152 | ||
153 | void * read_sha1_file(const unsigned char *sha1, char *type, unsigned long *size) | |
154 | { | |
155 | unsigned long mapsize; | |
156 | void *map, *buf; | |
157 | ||
158 | map = map_sha1_file(sha1, &mapsize); | |
159 | if (map) { | |
160 | buf = unpack_sha1_file(map, mapsize, type, size); | |
161 | munmap(map, mapsize); | |
162 | return buf; | |
163 | } | |
164 | return NULL; | |
165 | } | |
166 | ||
167 | int write_sha1_file(char *buf, unsigned len, unsigned char *returnsha1) | |
168 | { | |
169 | int size; | |
170 | char *compressed; | |
171 | z_stream stream; | |
172 | unsigned char sha1[20]; | |
173 | SHA_CTX c; | |
174 | ||
175 | /* Set it up */ | |
176 | memset(&stream, 0, sizeof(stream)); | |
177 | deflateInit(&stream, Z_BEST_COMPRESSION); | |
178 | size = deflateBound(&stream, len); | |
179 | compressed = malloc(size); | |
180 | ||
181 | /* Compress it */ | |
182 | stream.next_in = buf; | |
183 | stream.avail_in = len; | |
184 | stream.next_out = compressed; | |
185 | stream.avail_out = size; | |
186 | while (deflate(&stream, Z_FINISH) == Z_OK) | |
187 | /* nothing */; | |
188 | deflateEnd(&stream); | |
189 | size = stream.total_out; | |
190 | ||
191 | /* Sha1.. */ | |
192 | SHA1_Init(&c); | |
193 | SHA1_Update(&c, compressed, size); | |
194 | SHA1_Final(sha1, &c); | |
195 | ||
196 | if (write_sha1_buffer(sha1, compressed, size) < 0) | |
197 | return -1; | |
198 | if (returnsha1) | |
199 | memcpy(returnsha1, sha1, 20); | |
200 | return 0; | |
201 | } | |
202 | ||
203 | static inline int collision_check(char *filename, void *buf, unsigned int size) | |
204 | { | |
205 | #ifdef COLLISION_CHECK | |
206 | void *map; | |
207 | int fd = open(filename, O_RDONLY); | |
208 | struct stat st; | |
209 | int cmp; | |
210 | ||
211 | /* Unreadable object, or object went away? Strange. */ | |
212 | if (fd < 0) | |
213 | return -1; | |
214 | ||
215 | if (fstat(fd, &st) < 0 || size != st.st_size) | |
216 | return -1; | |
217 | ||
218 | map = mmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0); | |
219 | close(fd); | |
220 | if (map == MAP_FAILED) | |
221 | return -1; | |
222 | cmp = memcmp(buf, map, size); | |
223 | munmap(map, size); | |
224 | if (cmp) | |
225 | return -1; | |
226 | #endif | |
227 | return 0; | |
228 | } | |
229 | ||
230 | int write_sha1_buffer(const unsigned char *sha1, void *buf, unsigned int size) | |
231 | { | |
232 | char *filename = sha1_file_name(sha1); | |
233 | int fd; | |
234 | ||
235 | fd = open(filename, O_WRONLY | O_CREAT | O_EXCL, 0666); | |
236 | if (fd < 0) { | |
237 | if (errno != EEXIST) | |
238 | return -1; | |
239 | if (collision_check(filename, buf, size)) | |
240 | return error("SHA1 collision detected!" | |
241 | " This is bad, bad, BAD!\a\n"); | |
242 | return 0; | |
243 | } | |
244 | write(fd, buf, size); | |
245 | close(fd); | |
246 | return 0; | |
247 | } |