fsck-cache: warn about missing commit dates
[git/git.git] / sha1_file.c
CommitLineData
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
12const char *sha1_file_directory = NULL;
13
144bde78
LT
14#ifndef O_NOATIME
15#if defined(__linux__) && (defined(__i386__) || defined(__PPC__))
16#define O_NOATIME 01000000
17#else
18#define O_NOATIME 0
19#endif
20#endif
21
22static unsigned int sha1_file_open_flag = O_NOATIME;
23
0fcfd160
LT
24static unsigned hexval(char c)
25{
26 if (c >= '0' && c <= '9')
27 return c - '0';
28 if (c >= 'a' && c <= 'f')
29 return c - 'a' + 10;
30 if (c >= 'A' && c <= 'F')
31 return c - 'A' + 10;
32 return ~0;
33}
34
35int get_sha1_hex(const char *hex, unsigned char *sha1)
36{
37 int i;
38 for (i = 0; i < 20; i++) {
39 unsigned int val = (hexval(hex[0]) << 4) | hexval(hex[1]);
40 if (val & ~0xff)
41 return -1;
42 *sha1++ = val;
43 hex += 2;
44 }
45 return 0;
46}
47
48char * sha1_to_hex(const unsigned char *sha1)
49{
50 static char buffer[50];
51 static const char hex[] = "0123456789abcdef";
52 char *buf = buffer;
53 int i;
54
55 for (i = 0; i < 20; i++) {
56 unsigned int val = *sha1++;
57 *buf++ = hex[val >> 4];
58 *buf++ = hex[val & 0xf];
59 }
60 return buffer;
61}
62
63/*
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
66 * filename.
67 */
68char *sha1_file_name(const unsigned char *sha1)
69{
70 int i;
71 static char *name, *base;
72
73 if (!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);
79 base[len] = '/';
80 base[len+3] = '/';
81 name = base + len + 1;
82 }
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];
89 }
90 return base;
91}
92
d98b46f8 93int check_sha1_signature(unsigned char *sha1, void *map, unsigned long size, const char *type)
0fcfd160 94{
d98b46f8 95 char header[100];
0fcfd160
LT
96 unsigned char real_sha1[20];
97 SHA_CTX c;
98
99 SHA1_Init(&c);
d98b46f8 100 SHA1_Update(&c, header, 1+sprintf(header, "%s %lu", type, size));
0fcfd160
LT
101 SHA1_Update(&c, map, size);
102 SHA1_Final(real_sha1, &c);
103 return memcmp(sha1, real_sha1, 20) ? -1 : 0;
104}
105
106void *map_sha1_file(const unsigned char *sha1, unsigned long *size)
107{
108 char *filename = sha1_file_name(sha1);
0fcfd160
LT
109 struct stat st;
110 void *map;
144bde78 111 int fd;
0fcfd160 112
144bde78 113 fd = open(filename, O_RDONLY | sha1_file_open_flag);
0fcfd160 114 if (fd < 0) {
144bde78
LT
115 /* See if it works without O_NOATIME */
116 switch (sha1_file_open_flag) {
117 default:
118 fd = open(filename, O_RDONLY);
119 if (fd >= 0)
120 break;
121 /* Fallthrough */
122 case 0:
123 perror(filename);
124 return NULL;
125 }
126
127 /* If it failed once, it will probably fail again. Stop using O_NOATIME */
128 sha1_file_open_flag = 0;
0fcfd160
LT
129 }
130 if (fstat(fd, &st) < 0) {
131 close(fd);
132 return NULL;
133 }
134 map = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
135 close(fd);
136 if (-1 == (int)(long)map)
137 return NULL;
138 *size = st.st_size;
139 return map;
140}
141
142void * unpack_sha1_file(void *map, unsigned long mapsize, char *type, unsigned long *size)
143{
144 int ret, bytes;
145 z_stream stream;
146 char buffer[8192];
147 char *buf;
148
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);
155
156 inflateInit(&stream);
157 ret = inflate(&stream, 0);
da6abf5d
AG
158 if (ret < Z_OK)
159 return NULL;
0fcfd160
LT
160 if (sscanf(buffer, "%10s %lu", type, size) != 2)
161 return NULL;
162
163 bytes = strlen(buffer) + 1;
164 buf = malloc(*size);
165 if (!buf)
166 return NULL;
167
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)
174 /* nothing */;
175 }
176 inflateEnd(&stream);
177 return buf;
178}
179
180void * read_sha1_file(const unsigned char *sha1, char *type, unsigned long *size)
181{
182 unsigned long mapsize;
183 void *map, *buf;
184
185 map = map_sha1_file(sha1, &mapsize);
186 if (map) {
187 buf = unpack_sha1_file(map, mapsize, type, size);
188 munmap(map, mapsize);
189 return buf;
190 }
191 return NULL;
192}
193
f4913f91
JH
194void *read_tree_with_tree_or_commit_sha1(const unsigned char *sha1,
195 unsigned long *size,
196 unsigned char *tree_sha1_return)
197{
198 char type[20];
199 void *buffer;
200 unsigned long isize;
201 int was_commit = 0;
860edf7a 202 unsigned char tree_sha1[20];
f4913f91
JH
203
204 buffer = read_sha1_file(sha1, type, &isize);
205
206 /*
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 ").
211 */
212 if (buffer &&
213 !strcmp(type, "commit") &&
214 !get_sha1_hex(buffer + 5, tree_sha1)) {
215 free(buffer);
216 buffer = read_sha1_file(tree_sha1, type, &isize);
217 was_commit = 1;
218 }
219
220 /*
221 * Now do we have something and if so is it a tree?
222 */
223 if (!buffer || strcmp(type, "tree")) {
224 free(buffer);
860edf7a 225 return NULL;
f4913f91
JH
226 }
227
228 *size = isize;
229 if (tree_sha1_return)
230 memcpy(tree_sha1_return, was_commit ? tree_sha1 : sha1, 20);
231 return buffer;
232}
233
0fcfd160
LT
234int write_sha1_file(char *buf, unsigned len, unsigned char *returnsha1)
235{
236 int size;
237 char *compressed;
238 z_stream stream;
239 unsigned char sha1[20];
240 SHA_CTX c;
706bc531
LT
241 char *filename;
242 int fd;
0fcfd160 243
d98b46f8
LT
244 /* Sha1.. */
245 SHA1_Init(&c);
246 SHA1_Update(&c, buf, len);
247 SHA1_Final(sha1, &c);
248
706bc531
LT
249 if (returnsha1)
250 memcpy(returnsha1, sha1, 20);
251
252 filename = sha1_file_name(sha1);
253 fd = open(filename, O_WRONLY | O_CREAT | O_EXCL, 0666);
254 if (fd < 0) {
255 if (errno != EEXIST)
256 return -1;
257
258 /*
259 * We might do collision checking here, but we'd need to
260 * uncompress the old file and check it. Later.
261 */
262 return 0;
263 }
264
0fcfd160
LT
265 /* Set it up */
266 memset(&stream, 0, sizeof(stream));
267 deflateInit(&stream, Z_BEST_COMPRESSION);
268 size = deflateBound(&stream, len);
269 compressed = malloc(size);
270
271 /* Compress it */
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)
277 /* nothing */;
278 deflateEnd(&stream);
279 size = stream.total_out;
280
706bc531
LT
281 if (write(fd, compressed, size) != size)
282 die("unable to write file");
283 close(fd);
284
0fcfd160
LT
285 return 0;
286}
287
288static inline int collision_check(char *filename, void *buf, unsigned int size)
289{
290#ifdef COLLISION_CHECK
291 void *map;
292 int fd = open(filename, O_RDONLY);
293 struct stat st;
294 int cmp;
295
296 /* Unreadable object, or object went away? Strange. */
297 if (fd < 0)
298 return -1;
299
300 if (fstat(fd, &st) < 0 || size != st.st_size)
301 return -1;
302
303 map = mmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0);
304 close(fd);
305 if (map == MAP_FAILED)
306 return -1;
307 cmp = memcmp(buf, map, size);
308 munmap(map, size);
309 if (cmp)
310 return -1;
311#endif
312 return 0;
313}
314
315int write_sha1_buffer(const unsigned char *sha1, void *buf, unsigned int size)
316{
317 char *filename = sha1_file_name(sha1);
318 int fd;
319
320 fd = open(filename, O_WRONLY | O_CREAT | O_EXCL, 0666);
321 if (fd < 0) {
322 if (errno != EEXIST)
323 return -1;
324 if (collision_check(filename, buf, size))
325 return error("SHA1 collision detected!"
326 " This is bad, bad, BAD!\a\n");
327 return 0;
328 }
329 write(fd, buf, size);
330 close(fd);
331 return 0;
332}
8237b185
DB
333
334int write_sha1_from_fd(const unsigned char *sha1, int fd)
335{
336 char *filename = sha1_file_name(sha1);
337
338 int local;
339 z_stream stream;
340 unsigned char real_sha1[20];
341 char buf[4096];
342 char discard[4096];
343 int ret;
344 SHA_CTX c;
345
346 local = open(filename, O_WRONLY | O_CREAT | O_EXCL, 0666);
347
348 if (local < 0)
349 return error("Couldn't open %s\n", filename);
350
351 memset(&stream, 0, sizeof(stream));
352
353 inflateInit(&stream);
354
355 SHA1_Init(&c);
356
357 do {
358 ssize_t size;
359 size = read(fd, buf, 4096);
360 if (size <= 0) {
361 close(local);
362 unlink(filename);
363 if (!size)
364 return error("Connection closed?");
365 perror("Reading from connection");
366 return -1;
367 }
368 write(local, buf, size);
369 stream.avail_in = size;
370 stream.next_in = buf;
371 do {
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) -
376 stream.avail_out);
377 } while (stream.avail_in && ret == Z_OK);
378
379 } while (ret == Z_OK);
380 inflateEnd(&stream);
381
382 close(local);
383 SHA1_Final(real_sha1, &c);
384 if (ret != Z_STREAM_END) {
385 unlink(filename);
386 return error("File %s corrupted", sha1_to_hex(sha1));
387 }
388 if (memcmp(sha1, real_sha1, 20)) {
389 unlink(filename);
390 return error("File %s has bad hash\n", sha1_to_hex(sha1));
391 }
392
393 return 0;
394}
395
396int has_sha1_file(const unsigned char *sha1)
397{
398 char *filename = sha1_file_name(sha1);
399 struct stat st;
400
401 if (!stat(filename, &st))
402 return 1;
403 return 0;
404}