cvsserver: Eclipse compat - browsing 'modules' (heads in our case) works
[git/git.git] / refs.c
CommitLineData
95fc7512
DB
1#include "refs.h"
2#include "cache.h"
3
4#include <errno.h>
5
ca8db142
LT
6/* We allow "recursive" symbolic refs. Only within reason, though */
7#define MAXDEPTH 5
8
a876ed83 9const char *resolve_ref(const char *path, unsigned char *sha1, int reading)
8a65ff76 10{
a876ed83
JH
11 int depth = MAXDEPTH, len;
12 char buffer[256];
ca8db142 13
a876ed83
JH
14 for (;;) {
15 struct stat st;
16 char *buf;
17 int fd;
8a65ff76 18
a876ed83
JH
19 if (--depth < 0)
20 return NULL;
ca8db142 21
a876ed83
JH
22 /* Special case: non-existing file.
23 * Not having the refs/heads/new-branch is OK
24 * if we are writing into it, so is .git/HEAD
25 * that points at refs/heads/master still to be
26 * born. It is NOT OK if we are resolving for
27 * reading.
28 */
29 if (lstat(path, &st) < 0) {
30 if (reading || errno != ENOENT)
31 return NULL;
32 memset(sha1, 0, 20);
33 return path;
34 }
ca8db142 35
a876ed83
JH
36 /* Follow "normalized" - ie "refs/.." symlinks by hand */
37 if (S_ISLNK(st.st_mode)) {
38 len = readlink(path, buffer, sizeof(buffer)-1);
39 if (len >= 5 && !memcmp("refs/", buffer, 5)) {
40 path = git_path("%.*s", len, buffer);
41 continue;
42 }
ca8db142 43 }
a876ed83
JH
44
45 /*
46 * Anything else, just open it and try to use it as
47 * a ref
48 */
49 fd = open(path, O_RDONLY);
50 if (fd < 0)
51 return NULL;
52 len = read(fd, buffer, sizeof(buffer)-1);
53 close(fd);
54
55 /*
56 * Is it a symbolic ref?
57 */
58 if (len < 4 || memcmp("ref:", buffer, 4))
59 break;
60 buf = buffer + 4;
61 len -= 4;
62 while (len && isspace(*buf))
63 buf++, len--;
64 while (len && isspace(buf[len-1]))
65 buf[--len] = 0;
66 path = git_path("%.*s", len, buf);
8a65ff76 67 }
a876ed83
JH
68 if (len < 40 || get_sha1_hex(buffer, sha1))
69 return NULL;
70 return path;
71}
72
8098a178
JH
73int create_symref(const char *git_HEAD, const char *refs_heads_master)
74{
8098a178
JH
75 const char *lockpath;
76 char ref[1000];
77 int fd, len, written;
78
2fabd217 79#ifdef USE_SYMLINK_HEAD
f8348be3
JS
80 if (!only_use_symrefs) {
81 unlink(git_HEAD);
82 if (!symlink(refs_heads_master, git_HEAD))
83 return 0;
84 fprintf(stderr, "no symlink - falling back to symbolic ref\n");
85 }
303958dc
JS
86#endif
87
8098a178
JH
88 len = snprintf(ref, sizeof(ref), "ref: %s\n", refs_heads_master);
89 if (sizeof(ref) <= len) {
90 error("refname too long: %s", refs_heads_master);
91 return -1;
92 }
93 lockpath = mkpath("%s.lock", git_HEAD);
94 fd = open(lockpath, O_CREAT | O_EXCL | O_WRONLY, 0666);
95 written = write(fd, ref, len);
96 close(fd);
97 if (written != len) {
98 unlink(lockpath);
99 error("Unable to write to %s", lockpath);
100 return -2;
101 }
102 if (rename(lockpath, git_HEAD) < 0) {
103 unlink(lockpath);
104 error("Unable to create %s", git_HEAD);
105 return -3;
106 }
107 return 0;
8098a178
JH
108}
109
a876ed83
JH
110int read_ref(const char *filename, unsigned char *sha1)
111{
112 if (resolve_ref(filename, sha1, 1))
113 return 0;
114 return -1;
8a65ff76
LT
115}
116
944d8589 117static int do_for_each_ref(const char *base, int (*fn)(const char *path, const unsigned char *sha1))
8a65ff76
LT
118{
119 int retval = 0;
4ec99bf0 120 DIR *dir = opendir(git_path("%s", base));
8a65ff76
LT
121
122 if (dir) {
123 struct dirent *de;
124 int baselen = strlen(base);
125 char *path = xmalloc(baselen + 257);
6cada6a9
LT
126
127 if (!strncmp(base, "./", 2)) {
128 base += 2;
129 baselen -= 2;
130 }
8a65ff76 131 memcpy(path, base, baselen);
944d8589
LT
132 if (baselen && base[baselen-1] != '/')
133 path[baselen++] = '/';
8a65ff76
LT
134
135 while ((de = readdir(dir)) != NULL) {
136 unsigned char sha1[20];
137 struct stat st;
138 int namelen;
139
140 if (de->d_name[0] == '.')
141 continue;
142 namelen = strlen(de->d_name);
143 if (namelen > 255)
144 continue;
145 memcpy(path + baselen, de->d_name, namelen+1);
a7e66ae3 146 if (stat(git_path("%s", path), &st) < 0)
8a65ff76
LT
147 continue;
148 if (S_ISDIR(st.st_mode)) {
8a65ff76
LT
149 retval = do_for_each_ref(path, fn);
150 if (retval)
151 break;
152 continue;
153 }
ca8db142 154 if (read_ref(git_path("%s", path), sha1) < 0)
8a65ff76
LT
155 continue;
156 if (!has_sha1_file(sha1))
157 continue;
158 retval = fn(path, sha1);
159 if (retval)
160 break;
161 }
162 free(path);
163 closedir(dir);
164 }
165 return retval;
166}
167
723c31fe
LT
168int head_ref(int (*fn)(const char *path, const unsigned char *sha1))
169{
170 unsigned char sha1[20];
ca8db142 171 if (!read_ref(git_path("HEAD"), sha1))
99a0a6e0 172 return fn("HEAD", sha1);
2f34ba32 173 return 0;
723c31fe
LT
174}
175
944d8589 176int for_each_ref(int (*fn)(const char *path, const unsigned char *sha1))
8a65ff76 177{
99a0a6e0 178 return do_for_each_ref("refs", fn);
8a65ff76
LT
179}
180
95fc7512
DB
181static char *ref_file_name(const char *ref)
182{
183 char *base = get_refs_directory();
184 int baselen = strlen(base);
185 int reflen = strlen(ref);
186 char *ret = xmalloc(baselen + 2 + reflen);
187 sprintf(ret, "%s/%s", base, ref);
188 return ret;
189}
190
191static char *ref_lock_file_name(const char *ref)
192{
193 char *base = get_refs_directory();
194 int baselen = strlen(base);
195 int reflen = strlen(ref);
196 char *ret = xmalloc(baselen + 7 + reflen);
197 sprintf(ret, "%s/%s.lock", base, ref);
198 return ret;
199}
200
95fc7512
DB
201int get_ref_sha1(const char *ref, unsigned char *sha1)
202{
ca8db142
LT
203 const char *filename;
204
95fc7512
DB
205 if (check_ref_format(ref))
206 return -1;
ca8db142
LT
207 filename = git_path("refs/%s", ref);
208 return read_ref(filename, sha1);
95fc7512
DB
209}
210
211static int lock_ref_file(const char *filename, const char *lock_filename,
212 const unsigned char *old_sha1)
213{
214 int fd = open(lock_filename, O_WRONLY | O_CREAT | O_EXCL, 0666);
215 unsigned char current_sha1[20];
216 int retval;
217 if (fd < 0) {
218 return error("Couldn't open lock file for %s: %s",
219 filename, strerror(errno));
220 }
ca8db142 221 retval = read_ref(filename, current_sha1);
95fc7512
DB
222 if (old_sha1) {
223 if (retval) {
224 close(fd);
225 unlink(lock_filename);
226 return error("Could not read the current value of %s",
227 filename);
228 }
229 if (memcmp(current_sha1, old_sha1, 20)) {
230 close(fd);
231 unlink(lock_filename);
232 error("The current value of %s is %s",
233 filename, sha1_to_hex(current_sha1));
234 return error("Expected %s",
235 sha1_to_hex(old_sha1));
236 }
237 } else {
238 if (!retval) {
239 close(fd);
240 unlink(lock_filename);
241 return error("Unexpectedly found a value of %s for %s",
242 sha1_to_hex(current_sha1), filename);
243 }
244 }
245 return fd;
246}
247
248int lock_ref_sha1(const char *ref, const unsigned char *old_sha1)
249{
250 char *filename;
251 char *lock_filename;
252 int retval;
253 if (check_ref_format(ref))
254 return -1;
255 filename = ref_file_name(ref);
256 lock_filename = ref_lock_file_name(ref);
257 retval = lock_ref_file(filename, lock_filename, old_sha1);
258 free(filename);
259 free(lock_filename);
260 return retval;
261}
262
263static int write_ref_file(const char *filename,
264 const char *lock_filename, int fd,
265 const unsigned char *sha1)
266{
267 char *hex = sha1_to_hex(sha1);
268 char term = '\n';
269 if (write(fd, hex, 40) < 40 ||
270 write(fd, &term, 1) < 1) {
bd2afde8 271 error("Couldn't write %s", filename);
95fc7512
DB
272 close(fd);
273 return -1;
274 }
275 close(fd);
276 rename(lock_filename, filename);
277 return 0;
278}
279
280int write_ref_sha1(const char *ref, int fd, const unsigned char *sha1)
281{
282 char *filename;
283 char *lock_filename;
284 int retval;
285 if (fd < 0)
286 return -1;
287 if (check_ref_format(ref))
288 return -1;
289 filename = ref_file_name(ref);
290 lock_filename = ref_lock_file_name(ref);
64224caf
JH
291 if (safe_create_leading_directories(filename))
292 die("unable to create leading directory for %s", filename);
95fc7512
DB
293 retval = write_ref_file(filename, lock_filename, fd, sha1);
294 free(filename);
295 free(lock_filename);
296 return retval;
297}
298
03feddd6
JH
299/*
300 * Make sure "ref" is something reasonable to have under ".git/refs/";
301 * We do not like it if:
302 *
303 * - any path component of it begins with ".", or
304 * - it has double dots "..", or
305 * - it has ASCII control character, "~", "^", ":" or SP, anywhere, or
306 * - it ends with a "/".
307 */
308
309static inline int bad_ref_char(int ch)
310{
311 return (((unsigned) ch) <= ' ' ||
68283999
JH
312 ch == '~' || ch == '^' || ch == ':' ||
313 /* 2.13 Pattern Matching Notation */
314 ch == '?' || ch == '*' || ch == '[');
03feddd6
JH
315}
316
95fc7512
DB
317int check_ref_format(const char *ref)
318{
03feddd6
JH
319 int ch, level;
320 const char *cp = ref;
321
322 level = 0;
323 while (1) {
324 while ((ch = *cp++) == '/')
325 ; /* tolerate duplicated slashes */
326 if (!ch)
327 return -1; /* should not end with slashes */
328
329 /* we are at the beginning of the path component */
330 if (ch == '.' || bad_ref_char(ch))
331 return -1;
332
333 /* scan the rest of the path component */
334 while ((ch = *cp++) != 0) {
335 if (bad_ref_char(ch))
336 return -1;
337 if (ch == '/')
338 break;
339 if (ch == '.' && *cp == '.')
340 return -1;
341 }
342 level++;
343 if (!ch) {
344 if (level < 2)
345 return -1; /* at least of form "heads/blah" */
346 return 0;
347 }
348 }
95fc7512
DB
349}
350
351int write_ref_sha1_unlocked(const char *ref, const unsigned char *sha1)
352{
353 char *filename;
354 char *lock_filename;
355 int fd;
356 int retval;
357 if (check_ref_format(ref))
358 return -1;
359 filename = ref_file_name(ref);
360 lock_filename = ref_lock_file_name(ref);
64224caf
JH
361 if (safe_create_leading_directories(filename))
362 die("unable to create leading directory for %s", filename);
95fc7512
DB
363 fd = open(lock_filename, O_WRONLY | O_CREAT | O_EXCL, 0666);
364 if (fd < 0) {
365 error("Writing %s", lock_filename);
366 perror("Open");
367 }
368 retval = write_ref_file(filename, lock_filename, fd, sha1);
369 free(filename);
370 free(lock_filename);
371 return retval;
372}