91b2628e3c18e7f75e477c24197d9ef2eca14125
1 /*
2 * GIT - The information manager from hell
3 *
4 * Copyright (C) Linus Torvalds, 2005
5 */
6 #include "cache.h"
8 const char *sha1_file_directory = NULL;
9 struct cache_entry **active_cache = NULL;
10 unsigned int active_nr = 0, active_alloc = 0;
12 void usage(const char *err)
13 {
14 fprintf(stderr, "read-tree: %s\n", err);
15 exit(1);
16 }
18 static unsigned hexval(char c)
19 {
20 if (c >= '0' && c <= '9')
21 return c - '0';
22 if (c >= 'a' && c <= 'f')
23 return c - 'a' + 10;
24 if (c >= 'A' && c <= 'F')
25 return c - 'A' + 10;
26 return ~0;
27 }
29 int get_sha1_hex(const char *hex, unsigned char *sha1)
30 {
31 int i;
32 for (i = 0; i < 20; i++) {
33 unsigned int val = (hexval(hex[0]) << 4) | hexval(hex[1]);
34 if (val & ~0xff)
35 return -1;
36 *sha1++ = val;
37 hex += 2;
38 }
39 return 0;
40 }
42 char * sha1_to_hex(const unsigned char *sha1)
43 {
44 static char buffer[50];
45 static const char hex[] = "0123456789abcdef";
46 char *buf = buffer;
47 int i;
49 for (i = 0; i < 20; i++) {
50 unsigned int val = *sha1++;
51 *buf++ = hex[val >> 4];
52 *buf++ = hex[val & 0xf];
53 }
54 return buffer;
55 }
57 /*
58 * NOTE! This returns a statically allocated buffer, so you have to be
59 * careful about using it. Do a "strdup()" if you need to save the
60 * filename.
61 */
62 char *sha1_file_name(unsigned char *sha1)
63 {
64 int i;
65 static char *name, *base;
67 if (!base) {
68 char *sha1_file_directory = getenv(DB_ENVIRONMENT) ? : DEFAULT_DB_ENVIRONMENT;
69 int len = strlen(sha1_file_directory);
70 base = malloc(len + 60);
71 memcpy(base, sha1_file_directory, len);
72 memset(base+len, 0, 60);
73 base[len] = '/';
74 base[len+3] = '/';
75 name = base + len + 1;
76 }
77 for (i = 0; i < 20; i++) {
78 static char hex[] = "0123456789abcdef";
79 unsigned int val = sha1[i];
80 char *pos = name + i*2 + (i > 0);
81 *pos++ = hex[val >> 4];
82 *pos = hex[val & 0xf];
83 }
84 return base;
85 }
87 int check_sha1_signature(unsigned char *sha1, void *map, unsigned long size)
88 {
89 unsigned char real_sha1[20];
90 SHA_CTX c;
92 SHA1_Init(&c);
93 SHA1_Update(&c, map, size);
94 SHA1_Final(real_sha1, &c);
95 return memcmp(sha1, real_sha1, 20) ? -1 : 0;
96 }
98 void *map_sha1_file(unsigned char *sha1, unsigned long *size)
99 {
100 char *filename = sha1_file_name(sha1);
101 int fd = open(filename, O_RDONLY);
102 struct stat st;
103 void *map;
105 if (fd < 0) {
106 perror(filename);
107 return NULL;
108 }
109 if (fstat(fd, &st) < 0) {
110 close(fd);
111 return NULL;
112 }
113 map = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
114 close(fd);
115 if (-1 == (int)(long)map)
116 return NULL;
117 *size = st.st_size;
118 return map;
119 }
121 void * unpack_sha1_file(void *map, unsigned long mapsize, char *type, unsigned long *size)
122 {
123 int ret, bytes;
124 z_stream stream;
125 char buffer[8192];
126 char *buf;
128 /* Get the data stream */
129 memset(&stream, 0, sizeof(stream));
130 stream.next_in = map;
131 stream.avail_in = mapsize;
132 stream.next_out = buffer;
133 stream.avail_out = sizeof(buffer);
135 inflateInit(&stream);
136 ret = inflate(&stream, 0);
137 if (sscanf(buffer, "%10s %lu", type, size) != 2)
138 return NULL;
140 bytes = strlen(buffer) + 1;
141 buf = malloc(*size);
142 if (!buf)
143 return NULL;
145 memcpy(buf, buffer + bytes, stream.total_out - bytes);
146 bytes = stream.total_out - bytes;
147 if (bytes < *size && ret == Z_OK) {
148 stream.next_out = buf + bytes;
149 stream.avail_out = *size - bytes;
150 while (inflate(&stream, Z_FINISH) == Z_OK)
151 /* nothing */;
152 }
153 inflateEnd(&stream);
154 return buf;
155 }
157 void * read_sha1_file(unsigned char *sha1, char *type, unsigned long *size)
158 {
159 unsigned long mapsize;
160 void *map, *buf;
162 map = map_sha1_file(sha1, &mapsize);
163 if (map) {
164 buf = unpack_sha1_file(map, mapsize, type, size);
165 munmap(map, mapsize);
166 return buf;
167 }
168 return NULL;
169 }
171 int write_sha1_file(char *buf, unsigned len, unsigned char *returnsha1)
172 {
173 int size;
174 char *compressed;
175 z_stream stream;
176 unsigned char sha1[20];
177 SHA_CTX c;
179 /* Set it up */
180 memset(&stream, 0, sizeof(stream));
181 deflateInit(&stream, Z_BEST_COMPRESSION);
182 size = deflateBound(&stream, len);
183 compressed = malloc(size);
185 /* Compress it */
186 stream.next_in = buf;
187 stream.avail_in = len;
188 stream.next_out = compressed;
189 stream.avail_out = size;
190 while (deflate(&stream, Z_FINISH) == Z_OK)
191 /* nothing */;
192 deflateEnd(&stream);
193 size = stream.total_out;
195 /* Sha1.. */
196 SHA1_Init(&c);
197 SHA1_Update(&c, compressed, size);
198 SHA1_Final(sha1, &c);
200 if (write_sha1_buffer(sha1, compressed, size) < 0)
201 return -1;
202 if (returnsha1)
203 memcpy(returnsha1, sha1, 20);
204 return 0;
205 }
207 int write_sha1_buffer(unsigned char *sha1, void *buf, unsigned int size)
208 {
209 char *filename = sha1_file_name(sha1);
210 int fd;
212 fd = open(filename, O_WRONLY | O_CREAT | O_EXCL, 0666);
213 if (fd < 0)
214 return (errno == EEXIST) ? 0 : -1;
215 write(fd, buf, size);
216 close(fd);
217 return 0;
218 }
220 static int error(const char * string)
221 {
222 fprintf(stderr, "error: %s\n", string);
223 return -1;
224 }
226 int cache_match_stat(struct cache_entry *ce, struct stat *st)
227 {
228 unsigned int changed = 0;
230 if (ce->mtime.sec != (unsigned int)st->st_mtim.tv_sec ||
231 ce->mtime.nsec != (unsigned int)st->st_mtim.tv_nsec)
232 changed |= MTIME_CHANGED;
233 if (ce->ctime.sec != (unsigned int)st->st_ctim.tv_sec ||
234 ce->ctime.nsec != (unsigned int)st->st_ctim.tv_nsec)
235 changed |= CTIME_CHANGED;
236 if (ce->st_uid != (unsigned int)st->st_uid ||
237 ce->st_gid != (unsigned int)st->st_gid)
238 changed |= OWNER_CHANGED;
239 if (ce->st_mode != (unsigned int)st->st_mode)
240 changed |= MODE_CHANGED;
241 if (ce->st_dev != (unsigned int)st->st_dev ||
242 ce->st_ino != (unsigned int)st->st_ino)
243 changed |= INODE_CHANGED;
244 if (ce->st_size != (unsigned int)st->st_size)
245 changed |= DATA_CHANGED;
246 return changed;
247 }
249 int cache_name_compare(const char *name1, int len1, const char *name2, int len2)
250 {
251 int len = len1 < len2 ? len1 : len2;
252 int cmp;
254 cmp = memcmp(name1, name2, len);
255 if (cmp)
256 return cmp;
257 if (len1 < len2)
258 return -1;
259 if (len1 > len2)
260 return 1;
261 return 0;
262 }
264 int cache_name_pos(const char *name, int namelen)
265 {
266 int first, last;
268 first = 0;
269 last = active_nr;
270 while (last > first) {
271 int next = (last + first) >> 1;
272 struct cache_entry *ce = active_cache[next];
273 int cmp = cache_name_compare(name, namelen, ce->name, ce->namelen);
274 if (!cmp)
275 return -next-1;
276 if (cmp < 0) {
277 last = next;
278 continue;
279 }
280 first = next+1;
281 }
282 return first;
283 }
285 int remove_file_from_cache(char *path)
286 {
287 int pos = cache_name_pos(path, strlen(path));
288 if (pos < 0) {
289 pos = -pos-1;
290 active_nr--;
291 if (pos < active_nr)
292 memmove(active_cache + pos, active_cache + pos + 1, (active_nr - pos - 1) * sizeof(struct cache_entry *));
293 }
294 return 0;
295 }
297 int add_cache_entry(struct cache_entry *ce)
298 {
299 int pos;
301 pos = cache_name_pos(ce->name, ce->namelen);
303 /* existing match? Just replace it */
304 if (pos < 0) {
305 active_cache[-pos-1] = ce;
306 return 0;
307 }
309 /* Make sure the array is big enough .. */
310 if (active_nr == active_alloc) {
311 active_alloc = alloc_nr(active_alloc);
312 active_cache = realloc(active_cache, active_alloc * sizeof(struct cache_entry *));
313 }
315 /* Add it in.. */
316 active_nr++;
317 if (active_nr > pos)
318 memmove(active_cache + pos + 1, active_cache + pos, (active_nr - pos - 1) * sizeof(ce));
319 active_cache[pos] = ce;
320 return 0;
321 }
323 static int verify_hdr(struct cache_header *hdr, unsigned long size)
324 {
325 SHA_CTX c;
326 unsigned char sha1[20];
328 if (hdr->signature != CACHE_SIGNATURE)
329 return error("bad signature");
330 if (hdr->version != 1)
331 return error("bad version");
332 SHA1_Init(&c);
333 SHA1_Update(&c, hdr, offsetof(struct cache_header, sha1));
334 SHA1_Update(&c, hdr+1, size - sizeof(*hdr));
335 SHA1_Final(sha1, &c);
336 if (memcmp(sha1, hdr->sha1, 20))
337 return error("bad header sha1");
338 return 0;
339 }
341 int read_cache(void)
342 {
343 int fd, i;
344 struct stat st;
345 unsigned long size, offset;
346 void *map;
347 struct cache_header *hdr;
349 errno = EBUSY;
350 if (active_cache)
351 return error("more than one cachefile");
352 errno = ENOENT;
353 sha1_file_directory = getenv(DB_ENVIRONMENT);
354 if (!sha1_file_directory)
355 sha1_file_directory = DEFAULT_DB_ENVIRONMENT;
356 if (access(sha1_file_directory, X_OK) < 0)
357 return error("no access to SHA1 file directory");
358 fd = open(".dircache/index", O_RDONLY);
359 if (fd < 0)
360 return (errno == ENOENT) ? 0 : error("open failed");
362 size = 0; // avoid gcc warning
363 map = (void *)-1;
364 if (!fstat(fd, &st)) {
365 size = st.st_size;
366 errno = EINVAL;
367 if (size >= sizeof(struct cache_header))
368 map = mmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0);
369 }
370 close(fd);
371 if (-1 == (int)(long)map)
372 return error("mmap failed");
374 hdr = map;
375 if (verify_hdr(hdr, size) < 0)
376 goto unmap;
378 active_nr = hdr->entries;
379 active_alloc = alloc_nr(active_nr);
380 active_cache = calloc(active_alloc, sizeof(struct cache_entry *));
382 offset = sizeof(*hdr);
383 for (i = 0; i < hdr->entries; i++) {
384 struct cache_entry *ce = map + offset;
385 offset = offset + ce_size(ce);
386 active_cache[i] = ce;
387 }
388 return active_nr;
390 unmap:
391 munmap(map, size);
392 errno = EINVAL;
393 return error("verify header failed");
394 }
396 int write_cache(int newfd, struct cache_entry **cache, int entries)
397 {
398 SHA_CTX c;
399 struct cache_header hdr;
400 int i;
402 hdr.signature = CACHE_SIGNATURE;
403 hdr.version = 1;
404 hdr.entries = entries;
406 SHA1_Init(&c);
407 SHA1_Update(&c, &hdr, offsetof(struct cache_header, sha1));
408 for (i = 0; i < entries; i++) {
409 struct cache_entry *ce = cache[i];
410 int size = ce_size(ce);
411 SHA1_Update(&c, ce, size);
412 }
413 SHA1_Final(hdr.sha1, &c);
415 if (write(newfd, &hdr, sizeof(hdr)) != sizeof(hdr))
416 return -1;
418 for (i = 0; i < entries; i++) {
419 struct cache_entry *ce = cache[i];
420 int size = ce_size(ce);
421 if (write(newfd, ce, size) != size)
422 return -1;
423 }
424 return 0;
425 }