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 int get_sha1_file(const char *path, unsigned char *result)
51 int fd = open(path, O_RDONLY);
56 len = read(fd, buffer, sizeof(buffer));
60 return get_sha1_hex(buffer, result);
63 int get_sha1(const char *str, unsigned char *sha1)
65 static char pathname[PATH_MAX];
66 static const char *prefix[] = {
77 if (!get_sha1_hex(str, sha1))
81 for (p = prefix; *p; p++) {
82 snprintf(pathname, sizeof(pathname), "%s/%s/%s", gitdir, *p, str);
83 if (!get_sha1_file(pathname, sha1))
90 char * sha1_to_hex(const unsigned char *sha1)
92 static char buffer[50];
93 static const char hex[] = "0123456789abcdef";
97 for (i = 0; i < 20; i++) {
98 unsigned int val = *sha1++;
99 *buf++ = hex[val >> 4];
100 *buf++ = hex[val & 0xf];
106 * NOTE! This returns a statically allocated buffer, so you have to be
107 * careful about using it. Do a "strdup()" if you need to save the
110 char *sha1_file_name(const unsigned char *sha1)
113 static char *name, *base;
116 char *sha1_file_directory = getenv(DB_ENVIRONMENT) ? : DEFAULT_DB_ENVIRONMENT;
117 int len = strlen(sha1_file_directory);
118 base = xmalloc(len + 60);
119 memcpy(base, sha1_file_directory, len);
120 memset(base+len, 0, 60);
123 name = base + len + 1;
125 for (i = 0; i < 20; i++) {
126 static char hex[] = "0123456789abcdef";
127 unsigned int val = sha1[i];
128 char *pos = name + i*2 + (i > 0);
129 *pos++ = hex[val >> 4];
130 *pos = hex[val & 0xf];
135 int check_sha1_signature(unsigned char *sha1, void *map, unsigned long size, const char *type)
138 unsigned char real_sha1[20];
142 SHA1_Update(&c, header, 1+sprintf(header, "%s %lu", type, size));
143 SHA1_Update(&c, map, size);
144 SHA1_Final(real_sha1, &c);
145 return memcmp(sha1, real_sha1, 20) ? -1 : 0;
148 void *map_sha1_file(const unsigned char *sha1, unsigned long *size)
150 char *filename = sha1_file_name(sha1);
155 fd = open(filename, O_RDONLY | sha1_file_open_flag);
157 /* See if it works without O_NOATIME */
158 switch (sha1_file_open_flag) {
160 fd = open(filename, O_RDONLY);
169 /* If it failed once, it will probably fail again. Stop using O_NOATIME */
170 sha1_file_open_flag = 0;
172 if (fstat(fd, &st) < 0) {
176 map = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
178 if (-1 == (int)(long)map)
184 void * unpack_sha1_file(void *map, unsigned long mapsize, char *type, unsigned long *size)
191 /* Get the data stream */
192 memset(&stream, 0, sizeof(stream));
193 stream.next_in = map;
194 stream.avail_in = mapsize;
195 stream.next_out = buffer;
196 stream.avail_out = sizeof(buffer);
198 inflateInit(&stream);
199 ret = inflate(&stream, 0);
202 if (sscanf(buffer, "%10s %lu", type, size) != 2)
205 bytes = strlen(buffer) + 1;
206 buf = xmalloc(*size);
208 memcpy(buf, buffer + bytes, stream.total_out - bytes);
209 bytes = stream.total_out - bytes;
210 if (bytes < *size && ret == Z_OK) {
211 stream.next_out = buf + bytes;
212 stream.avail_out = *size - bytes;
213 while (inflate(&stream, Z_FINISH) == Z_OK)
220 void * read_sha1_file(const unsigned char *sha1, char *type, unsigned long *size)
222 unsigned long mapsize;
225 map = map_sha1_file(sha1, &mapsize);
227 buf = unpack_sha1_file(map, mapsize, type, size);
228 munmap(map, mapsize);
234 void *read_object_with_reference(const unsigned char *sha1,
235 const unsigned char *required_type,
237 unsigned char *actual_sha1_return)
242 unsigned char actual_sha1[20];
244 memcpy(actual_sha1, sha1, 20);
247 const char *ref_type = NULL;
249 buffer = read_sha1_file(actual_sha1, type, &isize);
252 if (!strcmp(type, required_type)) {
254 if (actual_sha1_return)
255 memcpy(actual_sha1_return, actual_sha1, 20);
258 /* Handle references */
259 else if (!strcmp(type, "commit"))
261 else if (!strcmp(type, "tag"))
262 ref_type = "object ";
267 ref_length = strlen(ref_type);
269 if (memcmp(buffer, ref_type, ref_length) ||
270 get_sha1_hex(buffer + ref_length, actual_sha1)) {
274 /* Now we have the ID of the referred-to object in
275 * actual_sha1. Check again. */
279 int write_sha1_file(char *buf, unsigned long len, const char *type, unsigned char *returnsha1)
284 unsigned char sha1[20];
287 static char tmpfile[PATH_MAX];
291 /* Generate the header */
292 hdrlen = sprintf(hdr, "%s %lu", type, len)+1;
296 SHA1_Update(&c, hdr, hdrlen);
297 SHA1_Update(&c, buf, len);
298 SHA1_Final(sha1, &c);
301 memcpy(returnsha1, sha1, 20);
303 filename = sha1_file_name(sha1);
304 fd = open(filename, O_RDONLY);
307 * FIXME!!! We might do collision checking here, but we'd
308 * need to uncompress the old file and check it. Later.
314 if (errno != ENOENT) {
315 fprintf(stderr, "sha1 file %s: %s", filename, strerror(errno));
319 snprintf(tmpfile, sizeof(tmpfile), "%s/obj_XXXXXX", get_object_directory());
320 fd = mkstemp(tmpfile);
322 fprintf(stderr, "unable to create temporary sha1 filename %s: %s", tmpfile, strerror(errno));
327 memset(&stream, 0, sizeof(stream));
328 deflateInit(&stream, Z_BEST_COMPRESSION);
329 size = deflateBound(&stream, len+hdrlen);
330 compressed = xmalloc(size);
333 stream.next_out = compressed;
334 stream.avail_out = size;
337 stream.next_in = hdr;
338 stream.avail_in = hdrlen;
339 while (deflate(&stream, 0) == Z_OK)
342 /* Then the data itself.. */
343 stream.next_in = buf;
344 stream.avail_in = len;
345 while (deflate(&stream, Z_FINISH) == Z_OK)
348 size = stream.total_out;
350 if (write(fd, compressed, size) != size)
351 die("unable to write file");
355 ret = link(tmpfile, filename);
360 * Coda hack - coda doesn't like cross-directory links,
361 * so we fall back to a rename, which will mean that it
362 * won't be able to check collisions, but that's not a
365 * When this succeeds, we just return 0. We have nothing
368 if (ret == EXDEV && !rename(tmpfile, filename))
374 fprintf(stderr, "unable to write sha1 filename %s: %s", filename, strerror(ret));
377 /* FIXME!!! Collision check here ? */
383 int write_sha1_from_fd(const unsigned char *sha1, int fd)
385 char *filename = sha1_file_name(sha1);
389 unsigned char real_sha1[20];
395 local = open(filename, O_WRONLY | O_CREAT | O_EXCL, 0666);
398 return error("Couldn't open %s\n", filename);
400 memset(&stream, 0, sizeof(stream));
402 inflateInit(&stream);
408 size = read(fd, buf, 4096);
413 return error("Connection closed?");
414 perror("Reading from connection");
417 write(local, buf, size);
418 stream.avail_in = size;
419 stream.next_in = buf;
421 stream.next_out = discard;
422 stream.avail_out = sizeof(discard);
423 ret = inflate(&stream, Z_SYNC_FLUSH);
424 SHA1_Update(&c, discard, sizeof(discard) -
426 } while (stream.avail_in && ret == Z_OK);
428 } while (ret == Z_OK);
432 SHA1_Final(real_sha1, &c);
433 if (ret != Z_STREAM_END) {
435 return error("File %s corrupted", sha1_to_hex(sha1));
437 if (memcmp(sha1, real_sha1, 20)) {
439 return error("File %s has bad hash\n", sha1_to_hex(sha1));
445 int has_sha1_file(const unsigned char *sha1)
447 char *filename = sha1_file_name(sha1);
450 if (!stat(filename, &st))
455 int index_fd(unsigned char *sha1, int fd, struct stat *st)
457 unsigned long size = st->st_size;
463 buf = mmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0);
465 if ((int)(long)buf == -1)
468 ret = write_sha1_file(buf, size, "blob", sha1);