2 * GIT - The information manager from hell
4 * Copyright (C) Linus Torvalds, 2005
6 * This handles basic git sha1 object files - packing, unpacking,
12 const char *sha1_file_directory = NULL;
14 static unsigned hexval(char c)
16 if (c >= '0' && c <= '9')
18 if (c >= 'a' && c <= 'f')
20 if (c >= 'A' && c <= 'F')
25 int get_sha1_hex(const char *hex, unsigned char *sha1)
28 for (i = 0; i < 20; i++) {
29 unsigned int val = (hexval(hex[0]) << 4) | hexval(hex[1]);
38 char * sha1_to_hex(const unsigned char *sha1)
40 static char buffer[50];
41 static const char hex[] = "0123456789abcdef";
45 for (i = 0; i < 20; i++) {
46 unsigned int val = *sha1++;
47 *buf++ = hex[val >> 4];
48 *buf++ = hex[val & 0xf];
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
58 char *sha1_file_name(const unsigned char *sha1)
61 static char *name, *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);
71 name = base + len + 1;
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];
83 int check_sha1_signature(unsigned char *sha1, void *map, unsigned long size)
85 unsigned char real_sha1[20];
89 SHA1_Update(&c, map, size);
90 SHA1_Final(real_sha1, &c);
91 return memcmp(sha1, real_sha1, 20) ? -1 : 0;
94 void *map_sha1_file(const unsigned char *sha1, unsigned long *size)
96 char *filename = sha1_file_name(sha1);
97 int fd = open(filename, O_RDONLY);
105 if (fstat(fd, &st) < 0) {
109 map = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
111 if (-1 == (int)(long)map)
117 void * unpack_sha1_file(void *map, unsigned long mapsize, char *type, unsigned long *size)
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);
131 inflateInit(&stream);
132 ret = inflate(&stream, 0);
133 if (sscanf(buffer, "%10s %lu", type, size) != 2)
136 bytes = strlen(buffer) + 1;
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)
153 void * read_sha1_file(const unsigned char *sha1, char *type, unsigned long *size)
155 unsigned long mapsize;
158 map = map_sha1_file(sha1, &mapsize);
160 buf = unpack_sha1_file(map, mapsize, type, size);
161 munmap(map, mapsize);
167 int write_sha1_file(char *buf, unsigned len, unsigned char *returnsha1)
172 unsigned char sha1[20];
176 memset(&stream, 0, sizeof(stream));
177 deflateInit(&stream, Z_BEST_COMPRESSION);
178 size = deflateBound(&stream, len);
179 compressed = malloc(size);
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)
189 size = stream.total_out;
193 SHA1_Update(&c, compressed, size);
194 SHA1_Final(sha1, &c);
196 if (write_sha1_buffer(sha1, compressed, size) < 0)
199 memcpy(returnsha1, sha1, 20);
203 static inline int collision_check(char *filename, void *buf, unsigned int size)
205 #ifdef COLLISION_CHECK
207 int fd = open(filename, O_RDONLY);
211 /* Unreadable object, or object went away? Strange. */
215 if (fstat(fd, &st) < 0 || size != st.st_size)
218 map = mmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0);
220 if (map == MAP_FAILED)
222 cmp = memcmp(buf, map, size);
230 int write_sha1_buffer(const unsigned char *sha1, void *buf, unsigned int size)
232 char *filename = sha1_file_name(sha1);
235 fd = open(filename, O_WRONLY | O_CREAT | O_EXCL, 0666);
239 if (collision_check(filename, buf, size))
240 return error("SHA1 collision detected!"
241 " This is bad, bad, BAD!\a\n");
244 write(fd, buf, size);