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;
15 #if defined(__linux__) && (defined(__i386__) || defined(__PPC__))
16 #define O_NOATIME 01000000
22 static unsigned int sha1_file_open_flag = O_NOATIME;
24 static unsigned hexval(char c)
26 if (c >= '0' && c <= '9')
28 if (c >= 'a' && c <= 'f')
30 if (c >= 'A' && c <= 'F')
35 int get_sha1_hex(const char *hex, unsigned char *sha1)
38 for (i = 0; i < 20; i++) {
39 unsigned int val = (hexval(hex[0]) << 4) | hexval(hex[1]);
48 char * sha1_to_hex(const unsigned char *sha1)
50 static char buffer[50];
51 static const char hex[] = "0123456789abcdef";
55 for (i = 0; i < 20; i++) {
56 unsigned int val = *sha1++;
57 *buf++ = hex[val >> 4];
58 *buf++ = hex[val & 0xf];
64 * NOTE! This returns a statically allocated buffer, so you have to be
65 * careful about using it. Do a "strdup()" if you need to save the
68 char *sha1_file_name(const unsigned char *sha1)
71 static char *name, *base;
74 char *sha1_file_directory = getenv(DB_ENVIRONMENT) ? : DEFAULT_DB_ENVIRONMENT;
75 int len = strlen(sha1_file_directory);
76 base = malloc(len + 60);
77 memcpy(base, sha1_file_directory, len);
78 memset(base+len, 0, 60);
81 name = base + len + 1;
83 for (i = 0; i < 20; i++) {
84 static char hex[] = "0123456789abcdef";
85 unsigned int val = sha1[i];
86 char *pos = name + i*2 + (i > 0);
87 *pos++ = hex[val >> 4];
88 *pos = hex[val & 0xf];
93 int check_sha1_signature(unsigned char *sha1, void *map, unsigned long size, const char *type)
96 unsigned char real_sha1[20];
100 SHA1_Update(&c, header, 1+sprintf(header, "%s %lu", type, size));
101 SHA1_Update(&c, map, size);
102 SHA1_Final(real_sha1, &c);
103 return memcmp(sha1, real_sha1, 20) ? -1 : 0;
106 void *map_sha1_file(const unsigned char *sha1, unsigned long *size)
108 char *filename = sha1_file_name(sha1);
113 fd = open(filename, O_RDONLY | sha1_file_open_flag);
115 /* See if it works without O_NOATIME */
116 switch (sha1_file_open_flag) {
118 fd = open(filename, O_RDONLY);
127 /* If it failed once, it will probably fail again. Stop using O_NOATIME */
128 sha1_file_open_flag = 0;
130 if (fstat(fd, &st) < 0) {
134 map = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
136 if (-1 == (int)(long)map)
142 void * unpack_sha1_file(void *map, unsigned long mapsize, char *type, unsigned long *size)
149 /* Get the data stream */
150 memset(&stream, 0, sizeof(stream));
151 stream.next_in = map;
152 stream.avail_in = mapsize;
153 stream.next_out = buffer;
154 stream.avail_out = sizeof(buffer);
156 inflateInit(&stream);
157 ret = inflate(&stream, 0);
160 if (sscanf(buffer, "%10s %lu", type, size) != 2)
163 bytes = strlen(buffer) + 1;
168 memcpy(buf, buffer + bytes, stream.total_out - bytes);
169 bytes = stream.total_out - bytes;
170 if (bytes < *size && ret == Z_OK) {
171 stream.next_out = buf + bytes;
172 stream.avail_out = *size - bytes;
173 while (inflate(&stream, Z_FINISH) == Z_OK)
180 void * read_sha1_file(const unsigned char *sha1, char *type, unsigned long *size)
182 unsigned long mapsize;
185 map = map_sha1_file(sha1, &mapsize);
187 buf = unpack_sha1_file(map, mapsize, type, size);
188 munmap(map, mapsize);
194 void *read_tree_with_tree_or_commit_sha1(const unsigned char *sha1,
196 unsigned char *tree_sha1_return)
202 unsigned char tree_sha1[20];
204 buffer = read_sha1_file(sha1, type, &isize);
207 * We might have read a commit instead of a tree, in which case
208 * we parse out the tree_sha1 and attempt to read from there.
209 * (buffer + 5) is because the tree sha1 is always at offset 5
210 * in a commit record ("tree ").
213 !strcmp(type, "commit") &&
214 !get_sha1_hex(buffer + 5, tree_sha1)) {
216 buffer = read_sha1_file(tree_sha1, type, &isize);
221 * Now do we have something and if so is it a tree?
223 if (!buffer || strcmp(type, "tree")) {
229 if (tree_sha1_return)
230 memcpy(tree_sha1_return, was_commit ? tree_sha1 : sha1, 20);
234 int write_sha1_file(char *buf, unsigned len, unsigned char *returnsha1)
239 unsigned char sha1[20];
246 SHA1_Update(&c, buf, len);
247 SHA1_Final(sha1, &c);
250 memcpy(returnsha1, sha1, 20);
252 filename = sha1_file_name(sha1);
253 fd = open(filename, O_WRONLY | O_CREAT | O_EXCL, 0666);
259 * We might do collision checking here, but we'd need to
260 * uncompress the old file and check it. Later.
266 memset(&stream, 0, sizeof(stream));
267 deflateInit(&stream, Z_BEST_COMPRESSION);
268 size = deflateBound(&stream, len);
269 compressed = malloc(size);
272 stream.next_in = buf;
273 stream.avail_in = len;
274 stream.next_out = compressed;
275 stream.avail_out = size;
276 while (deflate(&stream, Z_FINISH) == Z_OK)
279 size = stream.total_out;
281 if (write(fd, compressed, size) != size)
282 die("unable to write file");
288 static inline int collision_check(char *filename, void *buf, unsigned int size)
290 #ifdef COLLISION_CHECK
292 int fd = open(filename, O_RDONLY);
296 /* Unreadable object, or object went away? Strange. */
300 if (fstat(fd, &st) < 0 || size != st.st_size)
303 map = mmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0);
305 if (map == MAP_FAILED)
307 cmp = memcmp(buf, map, size);
315 int write_sha1_buffer(const unsigned char *sha1, void *buf, unsigned int size)
317 char *filename = sha1_file_name(sha1);
320 fd = open(filename, O_WRONLY | O_CREAT | O_EXCL, 0666);
324 if (collision_check(filename, buf, size))
325 return error("SHA1 collision detected!"
326 " This is bad, bad, BAD!\a\n");
329 write(fd, buf, size);
334 int write_sha1_from_fd(const unsigned char *sha1, int fd)
336 char *filename = sha1_file_name(sha1);
340 unsigned char real_sha1[20];
346 local = open(filename, O_WRONLY | O_CREAT | O_EXCL, 0666);
349 return error("Couldn't open %s\n", filename);
351 memset(&stream, 0, sizeof(stream));
353 inflateInit(&stream);
359 size = read(fd, buf, 4096);
364 return error("Connection closed?");
365 perror("Reading from connection");
368 write(local, buf, size);
369 stream.avail_in = size;
370 stream.next_in = buf;
372 stream.next_out = discard;
373 stream.avail_out = sizeof(discard);
374 ret = inflate(&stream, Z_SYNC_FLUSH);
375 SHA1_Update(&c, discard, sizeof(discard) -
377 } while (stream.avail_in && ret == Z_OK);
379 } while (ret == Z_OK);
383 SHA1_Final(real_sha1, &c);
384 if (ret != Z_STREAM_END) {
386 return error("File %s corrupted", sha1_to_hex(sha1));
388 if (memcmp(sha1, real_sha1, 20)) {
390 return error("File %s has bad hash\n", sha1_to_hex(sha1));
396 int has_sha1_file(const unsigned char *sha1)
398 char *filename = sha1_file_name(sha1);
401 if (!stat(filename, &st))