Some more sparse warning fixes
[git/git.git] / read-cache.c
CommitLineData
8bc9a0c7
LT
1/*
2 * GIT - The information manager from hell
3 *
4 * Copyright (C) Linus Torvalds, 2005
5 */
e83c5163
LT
6#include "cache.h"
7
e83c5163 8struct cache_entry **active_cache = NULL;
ee267527 9unsigned int active_nr = 0, active_alloc = 0, active_cache_changed = 0;
e83c5163 10
415e96c8
JH
11/*
12 * This only updates the "non-critical" parts of the directory
13 * cache, ie the parts that aren't tracked by GIT, and only used
14 * to validate the cache.
15 */
16void fill_stat_cache_info(struct cache_entry *ce, struct stat *st)
17{
18 ce->ce_ctime.sec = htonl(st->st_ctime);
19 ce->ce_mtime.sec = htonl(st->st_mtime);
20#ifdef NSEC
21 ce->ce_ctime.nsec = htonl(st->st_ctim.tv_nsec);
22 ce->ce_mtime.nsec = htonl(st->st_mtim.tv_nsec);
23#endif
24 ce->ce_dev = htonl(st->st_dev);
25 ce->ce_ino = htonl(st->st_ino);
26 ce->ce_uid = htonl(st->st_uid);
27 ce->ce_gid = htonl(st->st_gid);
28 ce->ce_size = htonl(st->st_size);
29}
30
5d728c84 31int ce_match_stat(struct cache_entry *ce, struct stat *st)
734aab75
LT
32{
33 unsigned int changed = 0;
34
8ae0a8c5
KS
35 switch (ntohl(ce->ce_mode) & S_IFMT) {
36 case S_IFREG:
37 changed |= !S_ISREG(st->st_mode) ? TYPE_CHANGED : 0;
ffbe1add
KS
38 /* We consider only the owner x bit to be relevant for "mode changes" */
39 if (0100 & (ntohl(ce->ce_mode) ^ st->st_mode))
40 changed |= MODE_CHANGED;
8ae0a8c5
KS
41 break;
42 case S_IFLNK:
43 changed |= !S_ISLNK(st->st_mode) ? TYPE_CHANGED : 0;
44 break;
45 default:
46 die("internal error: ce_mode is %o", ntohl(ce->ce_mode));
47 }
ccc4feb5 48 if (ce->ce_mtime.sec != htonl(st->st_mtime))
734aab75 49 changed |= MTIME_CHANGED;
ccc4feb5
LT
50 if (ce->ce_ctime.sec != htonl(st->st_ctime))
51 changed |= CTIME_CHANGED;
52
bdd4da59 53#ifdef NSEC
ccc4feb5
LT
54 /*
55 * nsec seems unreliable - not all filesystems support it, so
56 * as long as it is in the inode cache you get right nsec
57 * but after it gets flushed, you get zero nsec.
58 */
94dfb7f2 59 if (ce->ce_mtime.nsec != htonl(st->st_mtim.tv_nsec))
ccc4feb5 60 changed |= MTIME_CHANGED;
94dfb7f2 61 if (ce->ce_ctime.nsec != htonl(st->st_ctim.tv_nsec))
734aab75 62 changed |= CTIME_CHANGED;
ccc4feb5
LT
63#endif
64
65 if (ce->ce_uid != htonl(st->st_uid) ||
66 ce->ce_gid != htonl(st->st_gid))
734aab75 67 changed |= OWNER_CHANGED;
ccc4feb5
LT
68 if (ce->ce_dev != htonl(st->st_dev) ||
69 ce->ce_ino != htonl(st->st_ino))
734aab75 70 changed |= INODE_CHANGED;
ccc4feb5 71 if (ce->ce_size != htonl(st->st_size))
734aab75
LT
72 changed |= DATA_CHANGED;
73 return changed;
74}
75
958ba6c9
LT
76int base_name_compare(const char *name1, int len1, int mode1,
77 const char *name2, int len2, int mode2)
78{
79 unsigned char c1, c2;
80 int len = len1 < len2 ? len1 : len2;
81 int cmp;
82
83 cmp = memcmp(name1, name2, len);
84 if (cmp)
85 return cmp;
86 c1 = name1[len];
87 c2 = name2[len];
88 if (!c1 && S_ISDIR(mode1))
89 c1 = '/';
90 if (!c2 && S_ISDIR(mode2))
91 c2 = '/';
92 return (c1 < c2) ? -1 : (c1 > c2) ? 1 : 0;
93}
94
95fd5bf8 95int cache_name_compare(const char *name1, int flags1, const char *name2, int flags2)
eb38c22f 96{
95fd5bf8
LT
97 int len1 = flags1 & CE_NAMEMASK;
98 int len2 = flags2 & CE_NAMEMASK;
eb38c22f
LT
99 int len = len1 < len2 ? len1 : len2;
100 int cmp;
101
102 cmp = memcmp(name1, name2, len);
103 if (cmp)
104 return cmp;
105 if (len1 < len2)
106 return -1;
107 if (len1 > len2)
108 return 1;
95fd5bf8
LT
109 if (flags1 < flags2)
110 return -1;
111 if (flags1 > flags2)
112 return 1;
eb38c22f
LT
113 return 0;
114}
115
116int cache_name_pos(const char *name, int namelen)
117{
118 int first, last;
119
120 first = 0;
121 last = active_nr;
122 while (last > first) {
123 int next = (last + first) >> 1;
124 struct cache_entry *ce = active_cache[next];
95fd5bf8 125 int cmp = cache_name_compare(name, namelen, ce->name, htons(ce->ce_flags));
eb38c22f 126 if (!cmp)
76e7f4ec 127 return next;
eb38c22f
LT
128 if (cmp < 0) {
129 last = next;
130 continue;
131 }
132 first = next+1;
133 }
76e7f4ec 134 return -first-1;
eb38c22f
LT
135}
136
7b937ca3 137/* Remove entry, return true if there are more entries to go.. */
dbbce55b 138int remove_cache_entry_at(int pos)
7b937ca3 139{
ee267527 140 active_cache_changed = 1;
7b937ca3
LT
141 active_nr--;
142 if (pos >= active_nr)
143 return 0;
144 memmove(active_cache + pos, active_cache + pos + 1, (active_nr - pos) * sizeof(struct cache_entry *));
145 return 1;
146}
147
197ee8c9
LT
148int remove_file_from_cache(char *path)
149{
150 int pos = cache_name_pos(path, strlen(path));
c4e3cca1
JH
151 if (pos < 0)
152 pos = -pos-1;
153 while (pos < active_nr && !strcmp(active_cache[pos]->name, path))
dbbce55b 154 remove_cache_entry_at(pos);
197ee8c9
LT
155 return 0;
156}
157
dbbce55b 158int ce_same_name(struct cache_entry *a, struct cache_entry *b)
7b937ca3
LT
159{
160 int len = ce_namelen(a);
161 return ce_namelen(b) == len && !memcmp(a->name, b->name, len);
162}
163
0f1e4f04
JH
164/* We may be in a situation where we already have path/file and path
165 * is being added, or we already have path and path/file is being
166 * added. Either one would result in a nonsense tree that has path
167 * twice when git-write-tree tries to write it out. Prevent it.
192268c1
JH
168 *
169 * If ok-to-replace is specified, we remove the conflicting entries
170 * from the cache so the caller should recompute the insert position.
171 * When this happens, we return non-zero.
0f1e4f04 172 */
192268c1
JH
173static int check_file_directory_conflict(const struct cache_entry *ce,
174 int ok_to_replace)
0f1e4f04 175{
192268c1 176 int pos, replaced = 0;
0f1e4f04
JH
177 const char *path = ce->name;
178 int namelen = strlen(path);
179 int stage = ce_stage(ce);
180 char *pathbuf = xmalloc(namelen + 1);
181 char *cp;
182
183 memcpy(pathbuf, path, namelen + 1);
184
185 /*
186 * We are inserting path/file. Do they have path registered at
187 * the same stage? We need to do this for all the levels of our
188 * subpath.
189 */
190 cp = pathbuf;
191 while (1) {
192 char *ep = strchr(cp, '/');
aa575f81 193 if (!ep)
0f1e4f04
JH
194 break;
195 *ep = 0; /* first cut it at slash */
196 pos = cache_name_pos(pathbuf,
197 htons(create_ce_flags(ep-cp, stage)));
198 if (0 <= pos) {
199 /* Our leading path component is registered as a file,
200 * and we are trying to make it a directory. This is
201 * bad.
202 */
192268c1
JH
203 if (!ok_to_replace) {
204 free(pathbuf);
205 return -1;
206 }
207 fprintf(stderr, "removing file '%s' to replace it with a directory to create '%s'.\n", pathbuf, path);
dbbce55b 208 remove_cache_entry_at(pos);
192268c1 209 replaced = 1;
0f1e4f04
JH
210 }
211 *ep = '/'; /* then restore it and go downwards */
212 cp = ep + 1;
213 }
214 free(pathbuf);
215
216 /* Do we have an entry in the cache that makes our path a prefix
217 * of it? That is, are we creating a file where they already expect
218 * a directory there?
219 */
220 pos = cache_name_pos(path,
221 htons(create_ce_flags(namelen, stage)));
222
223 /* (0 <= pos) cannot happen because add_cache_entry()
224 * should have taken care of that case.
225 */
226 pos = -pos-1;
227
228 /* pos would point at an existing entry that would come immediately
229 * after our path. It could be the same as our path in higher stage,
230 * or different path but in a lower stage.
231 *
232 * E.g. when we are inserting path at stage 2,
233 *
234 * 1 path
235 * pos-> 3 path
192268c1
JH
236 * 2 path/file1
237 * 3 path/file1
238 * 2 path/file2
239 * 2 patho
0f1e4f04
JH
240 *
241 * We need to examine pos, ignore it because it is at different
242 * stage, examine next to find the path/file at stage 2, and
192268c1
JH
243 * complain. We need to do this until we are not the leading
244 * path of an existing entry anymore.
0f1e4f04
JH
245 */
246
247 while (pos < active_nr) {
248 struct cache_entry *other = active_cache[pos];
249 if (strncmp(other->name, path, namelen))
250 break; /* it is not our "subdirectory" anymore */
192268c1
JH
251 if ((ce_stage(other) == stage) &&
252 other->name[namelen] == '/') {
253 if (!ok_to_replace)
254 return -1;
255 fprintf(stderr, "removing file '%s' under '%s' to be replaced with a file\n", other->name, path);
dbbce55b 256 remove_cache_entry_at(pos);
192268c1
JH
257 replaced = 1;
258 continue; /* cycle without updating pos */
259 }
0f1e4f04
JH
260 pos++;
261 }
192268c1 262 return replaced;
0f1e4f04
JH
263}
264
192268c1 265int add_cache_entry(struct cache_entry *ce, int option)
197ee8c9
LT
266{
267 int pos;
192268c1
JH
268 int ok_to_add = option & ADD_CACHE_OK_TO_ADD;
269 int ok_to_replace = option & ADD_CACHE_OK_TO_REPLACE;
95fd5bf8 270 pos = cache_name_pos(ce->name, htons(ce->ce_flags));
197ee8c9
LT
271
272 /* existing match? Just replace it */
76e7f4ec 273 if (pos >= 0) {
ee267527 274 active_cache_changed = 1;
76e7f4ec 275 active_cache[pos] = ce;
197ee8c9
LT
276 return 0;
277 }
76e7f4ec 278 pos = -pos-1;
197ee8c9 279
7b937ca3
LT
280 /*
281 * Inserting a merged entry ("stage 0") into the index
282 * will always replace all non-merged entries..
283 */
284 if (pos < active_nr && ce_stage(ce) == 0) {
dbbce55b 285 while (ce_same_name(active_cache[pos], ce)) {
7b937ca3 286 ok_to_add = 1;
dbbce55b 287 if (!remove_cache_entry_at(pos))
7b937ca3
LT
288 break;
289 }
290 }
291
121481ab
LT
292 if (!ok_to_add)
293 return -1;
294
192268c1
JH
295 if (check_file_directory_conflict(ce, ok_to_replace)) {
296 if (!ok_to_replace)
297 return -1;
298 pos = cache_name_pos(ce->name, htons(ce->ce_flags));
299 pos = -pos-1;
300 }
0f1e4f04 301
197ee8c9
LT
302 /* Make sure the array is big enough .. */
303 if (active_nr == active_alloc) {
304 active_alloc = alloc_nr(active_alloc);
812666c8 305 active_cache = xrealloc(active_cache, active_alloc * sizeof(struct cache_entry *));
197ee8c9
LT
306 }
307
308 /* Add it in.. */
309 active_nr++;
310 if (active_nr > pos)
311 memmove(active_cache + pos + 1, active_cache + pos, (active_nr - pos - 1) * sizeof(ce));
312 active_cache[pos] = ce;
ee267527 313 active_cache_changed = 1;
197ee8c9
LT
314 return 0;
315}
316
e83c5163
LT
317static int verify_hdr(struct cache_header *hdr, unsigned long size)
318{
319 SHA_CTX c;
320 unsigned char sha1[20];
321
ccc4feb5 322 if (hdr->hdr_signature != htonl(CACHE_SIGNATURE))
e83c5163 323 return error("bad signature");
ca9be054
LT
324 if (hdr->hdr_version != htonl(2))
325 return error("bad index version");
e83c5163 326 SHA1_Init(&c);
ca9be054 327 SHA1_Update(&c, hdr, size - 20);
e83c5163 328 SHA1_Final(sha1, &c);
ca9be054
LT
329 if (memcmp(sha1, (void *)hdr + size - 20, 20))
330 return error("bad index file sha1 signature");
e83c5163
LT
331 return 0;
332}
333
334int read_cache(void)
335{
336 int fd, i;
337 struct stat st;
338 unsigned long size, offset;
339 void *map;
340 struct cache_header *hdr;
341
342 errno = EBUSY;
343 if (active_cache)
344 return error("more than one cachefile");
345 errno = ENOENT;
bb233d69 346 fd = open(get_index_file(), O_RDONLY);
e83c5163
LT
347 if (fd < 0)
348 return (errno == ENOENT) ? 0 : error("open failed");
349
19b2860c 350 size = 0; // avoid gcc warning
e83c5163
LT
351 map = (void *)-1;
352 if (!fstat(fd, &st)) {
e83c5163
LT
353 size = st.st_size;
354 errno = EINVAL;
ca9be054 355 if (size >= sizeof(struct cache_header) + 20)
520fc241 356 map = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_PRIVATE, fd, 0);
e83c5163
LT
357 }
358 close(fd);
359 if (-1 == (int)(long)map)
360 return error("mmap failed");
361
362 hdr = map;
363 if (verify_hdr(hdr, size) < 0)
364 goto unmap;
365
ccc4feb5 366 active_nr = ntohl(hdr->hdr_entries);
e83c5163
LT
367 active_alloc = alloc_nr(active_nr);
368 active_cache = calloc(active_alloc, sizeof(struct cache_entry *));
369
370 offset = sizeof(*hdr);
ccc4feb5 371 for (i = 0; i < active_nr; i++) {
e83c5163
LT
372 struct cache_entry *ce = map + offset;
373 offset = offset + ce_size(ce);
374 active_cache[i] = ce;
375 }
376 return active_nr;
377
378unmap:
379 munmap(map, size);
380 errno = EINVAL;
381 return error("verify header failed");
382}
383
4990aadc 384#define WRITE_BUFFER_SIZE 8192
bf0f910d 385static unsigned char write_buffer[WRITE_BUFFER_SIZE];
4990aadc
LT
386static unsigned long write_buffer_len;
387
ca9be054 388static int ce_write(SHA_CTX *context, int fd, void *data, unsigned int len)
4990aadc
LT
389{
390 while (len) {
391 unsigned int buffered = write_buffer_len;
392 unsigned int partial = WRITE_BUFFER_SIZE - buffered;
393 if (partial > len)
394 partial = len;
395 memcpy(write_buffer + buffered, data, partial);
396 buffered += partial;
397 if (buffered == WRITE_BUFFER_SIZE) {
ca9be054 398 SHA1_Update(context, write_buffer, WRITE_BUFFER_SIZE);
4990aadc
LT
399 if (write(fd, write_buffer, WRITE_BUFFER_SIZE) != WRITE_BUFFER_SIZE)
400 return -1;
401 buffered = 0;
402 }
403 write_buffer_len = buffered;
404 len -= partial;
405 data += partial;
406 }
407 return 0;
408}
409
ca9be054 410static int ce_flush(SHA_CTX *context, int fd)
4990aadc
LT
411{
412 unsigned int left = write_buffer_len;
ca9be054 413
4990aadc
LT
414 if (left) {
415 write_buffer_len = 0;
ca9be054 416 SHA1_Update(context, write_buffer, left);
4990aadc 417 }
ca9be054
LT
418
419 /* Append the SHA1 signature at the end */
420 SHA1_Final(write_buffer + left, context);
421 left += 20;
422 if (write(fd, write_buffer, left) != left)
423 return -1;
4990aadc
LT
424 return 0;
425}
426
197ee8c9
LT
427int write_cache(int newfd, struct cache_entry **cache, int entries)
428{
429 SHA_CTX c;
430 struct cache_header hdr;
431 int i;
432
ccc4feb5 433 hdr.hdr_signature = htonl(CACHE_SIGNATURE);
ca9be054 434 hdr.hdr_version = htonl(2);
ccc4feb5 435 hdr.hdr_entries = htonl(entries);
197ee8c9
LT
436
437 SHA1_Init(&c);
ca9be054 438 if (ce_write(&c, newfd, &hdr, sizeof(hdr)) < 0)
197ee8c9
LT
439 return -1;
440
441 for (i = 0; i < entries; i++) {
442 struct cache_entry *ce = cache[i];
ca9be054 443 if (ce_write(&c, newfd, ce, ce_size(ce)) < 0)
197ee8c9
LT
444 return -1;
445 }
ca9be054 446 return ce_flush(&c, newfd);
197ee8c9 447}