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Commit | Line | Data |
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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 | ||
8098a178 JH |
9 | #ifndef USE_SYMLINK_HEAD |
10 | #define USE_SYMLINK_HEAD 1 | |
11 | #endif | |
12 | ||
13 | int validate_symref(const char *path) | |
14 | { | |
15 | struct stat st; | |
16 | char *buf, buffer[256]; | |
17 | int len, fd; | |
18 | ||
19 | if (lstat(path, &st) < 0) | |
20 | return -1; | |
21 | ||
22 | /* Make sure it is a "refs/.." symlink */ | |
23 | if (S_ISLNK(st.st_mode)) { | |
24 | len = readlink(path, buffer, sizeof(buffer)-1); | |
25 | if (len >= 5 && !memcmp("refs/", buffer, 5)) | |
26 | return 0; | |
27 | return -1; | |
28 | } | |
29 | ||
30 | /* | |
31 | * Anything else, just open it and try to see if it is a symbolic ref. | |
32 | */ | |
33 | fd = open(path, O_RDONLY); | |
34 | if (fd < 0) | |
35 | return -1; | |
36 | len = read(fd, buffer, sizeof(buffer)-1); | |
37 | close(fd); | |
38 | ||
39 | /* | |
40 | * Is it a symbolic ref? | |
41 | */ | |
42 | if (len < 4 || memcmp("ref:", buffer, 4)) | |
43 | return -1; | |
44 | buf = buffer + 4; | |
45 | len -= 4; | |
46 | while (len && isspace(*buf)) | |
47 | buf++, len--; | |
85912b06 | 48 | if (len >= 5 && !memcmp("refs/", buf, 5)) |
8098a178 JH |
49 | return 0; |
50 | return -1; | |
51 | } | |
52 | ||
a876ed83 | 53 | const char *resolve_ref(const char *path, unsigned char *sha1, int reading) |
8a65ff76 | 54 | { |
a876ed83 JH |
55 | int depth = MAXDEPTH, len; |
56 | char buffer[256]; | |
ca8db142 | 57 | |
a876ed83 JH |
58 | for (;;) { |
59 | struct stat st; | |
60 | char *buf; | |
61 | int fd; | |
8a65ff76 | 62 | |
a876ed83 JH |
63 | if (--depth < 0) |
64 | return NULL; | |
ca8db142 | 65 | |
a876ed83 JH |
66 | /* Special case: non-existing file. |
67 | * Not having the refs/heads/new-branch is OK | |
68 | * if we are writing into it, so is .git/HEAD | |
69 | * that points at refs/heads/master still to be | |
70 | * born. It is NOT OK if we are resolving for | |
71 | * reading. | |
72 | */ | |
73 | if (lstat(path, &st) < 0) { | |
74 | if (reading || errno != ENOENT) | |
75 | return NULL; | |
76 | memset(sha1, 0, 20); | |
77 | return path; | |
78 | } | |
ca8db142 | 79 | |
a876ed83 JH |
80 | /* Follow "normalized" - ie "refs/.." symlinks by hand */ |
81 | if (S_ISLNK(st.st_mode)) { | |
82 | len = readlink(path, buffer, sizeof(buffer)-1); | |
83 | if (len >= 5 && !memcmp("refs/", buffer, 5)) { | |
84 | path = git_path("%.*s", len, buffer); | |
85 | continue; | |
86 | } | |
ca8db142 | 87 | } |
a876ed83 JH |
88 | |
89 | /* | |
90 | * Anything else, just open it and try to use it as | |
91 | * a ref | |
92 | */ | |
93 | fd = open(path, O_RDONLY); | |
94 | if (fd < 0) | |
95 | return NULL; | |
96 | len = read(fd, buffer, sizeof(buffer)-1); | |
97 | close(fd); | |
98 | ||
99 | /* | |
100 | * Is it a symbolic ref? | |
101 | */ | |
102 | if (len < 4 || memcmp("ref:", buffer, 4)) | |
103 | break; | |
104 | buf = buffer + 4; | |
105 | len -= 4; | |
106 | while (len && isspace(*buf)) | |
107 | buf++, len--; | |
108 | while (len && isspace(buf[len-1])) | |
109 | buf[--len] = 0; | |
110 | path = git_path("%.*s", len, buf); | |
8a65ff76 | 111 | } |
a876ed83 JH |
112 | if (len < 40 || get_sha1_hex(buffer, sha1)) |
113 | return NULL; | |
114 | return path; | |
115 | } | |
116 | ||
8098a178 JH |
117 | int create_symref(const char *git_HEAD, const char *refs_heads_master) |
118 | { | |
8098a178 JH |
119 | const char *lockpath; |
120 | char ref[1000]; | |
121 | int fd, len, written; | |
122 | ||
303958dc JS |
123 | #if USE_SYMLINK_HEAD |
124 | unlink(git_HEAD); | |
125 | if (!symlink(refs_heads_master, git_HEAD)) | |
126 | return 0; | |
127 | fprintf(stderr, "no symlink - falling back to symbolic ref\n"); | |
128 | #endif | |
129 | ||
8098a178 JH |
130 | len = snprintf(ref, sizeof(ref), "ref: %s\n", refs_heads_master); |
131 | if (sizeof(ref) <= len) { | |
132 | error("refname too long: %s", refs_heads_master); | |
133 | return -1; | |
134 | } | |
135 | lockpath = mkpath("%s.lock", git_HEAD); | |
136 | fd = open(lockpath, O_CREAT | O_EXCL | O_WRONLY, 0666); | |
137 | written = write(fd, ref, len); | |
138 | close(fd); | |
139 | if (written != len) { | |
140 | unlink(lockpath); | |
141 | error("Unable to write to %s", lockpath); | |
142 | return -2; | |
143 | } | |
144 | if (rename(lockpath, git_HEAD) < 0) { | |
145 | unlink(lockpath); | |
146 | error("Unable to create %s", git_HEAD); | |
147 | return -3; | |
148 | } | |
149 | return 0; | |
8098a178 JH |
150 | } |
151 | ||
a876ed83 JH |
152 | int read_ref(const char *filename, unsigned char *sha1) |
153 | { | |
154 | if (resolve_ref(filename, sha1, 1)) | |
155 | return 0; | |
156 | return -1; | |
8a65ff76 LT |
157 | } |
158 | ||
944d8589 | 159 | static int do_for_each_ref(const char *base, int (*fn)(const char *path, const unsigned char *sha1)) |
8a65ff76 LT |
160 | { |
161 | int retval = 0; | |
4ec99bf0 | 162 | DIR *dir = opendir(git_path("%s", base)); |
8a65ff76 LT |
163 | |
164 | if (dir) { | |
165 | struct dirent *de; | |
166 | int baselen = strlen(base); | |
167 | char *path = xmalloc(baselen + 257); | |
6cada6a9 LT |
168 | |
169 | if (!strncmp(base, "./", 2)) { | |
170 | base += 2; | |
171 | baselen -= 2; | |
172 | } | |
8a65ff76 | 173 | memcpy(path, base, baselen); |
944d8589 LT |
174 | if (baselen && base[baselen-1] != '/') |
175 | path[baselen++] = '/'; | |
8a65ff76 LT |
176 | |
177 | while ((de = readdir(dir)) != NULL) { | |
178 | unsigned char sha1[20]; | |
179 | struct stat st; | |
180 | int namelen; | |
181 | ||
182 | if (de->d_name[0] == '.') | |
183 | continue; | |
184 | namelen = strlen(de->d_name); | |
185 | if (namelen > 255) | |
186 | continue; | |
187 | memcpy(path + baselen, de->d_name, namelen+1); | |
a7e66ae3 | 188 | if (stat(git_path("%s", path), &st) < 0) |
8a65ff76 LT |
189 | continue; |
190 | if (S_ISDIR(st.st_mode)) { | |
8a65ff76 LT |
191 | retval = do_for_each_ref(path, fn); |
192 | if (retval) | |
193 | break; | |
194 | continue; | |
195 | } | |
ca8db142 | 196 | if (read_ref(git_path("%s", path), sha1) < 0) |
8a65ff76 LT |
197 | continue; |
198 | if (!has_sha1_file(sha1)) | |
199 | continue; | |
200 | retval = fn(path, sha1); | |
201 | if (retval) | |
202 | break; | |
203 | } | |
204 | free(path); | |
205 | closedir(dir); | |
206 | } | |
207 | return retval; | |
208 | } | |
209 | ||
723c31fe LT |
210 | int head_ref(int (*fn)(const char *path, const unsigned char *sha1)) |
211 | { | |
212 | unsigned char sha1[20]; | |
ca8db142 | 213 | if (!read_ref(git_path("HEAD"), sha1)) |
99a0a6e0 | 214 | return fn("HEAD", sha1); |
2f34ba32 | 215 | return 0; |
723c31fe LT |
216 | } |
217 | ||
944d8589 | 218 | int for_each_ref(int (*fn)(const char *path, const unsigned char *sha1)) |
8a65ff76 | 219 | { |
99a0a6e0 | 220 | return do_for_each_ref("refs", fn); |
8a65ff76 LT |
221 | } |
222 | ||
95fc7512 DB |
223 | static char *ref_file_name(const char *ref) |
224 | { | |
225 | char *base = get_refs_directory(); | |
226 | int baselen = strlen(base); | |
227 | int reflen = strlen(ref); | |
228 | char *ret = xmalloc(baselen + 2 + reflen); | |
229 | sprintf(ret, "%s/%s", base, ref); | |
230 | return ret; | |
231 | } | |
232 | ||
233 | static char *ref_lock_file_name(const char *ref) | |
234 | { | |
235 | char *base = get_refs_directory(); | |
236 | int baselen = strlen(base); | |
237 | int reflen = strlen(ref); | |
238 | char *ret = xmalloc(baselen + 7 + reflen); | |
239 | sprintf(ret, "%s/%s.lock", base, ref); | |
240 | return ret; | |
241 | } | |
242 | ||
95fc7512 DB |
243 | int get_ref_sha1(const char *ref, unsigned char *sha1) |
244 | { | |
ca8db142 LT |
245 | const char *filename; |
246 | ||
95fc7512 DB |
247 | if (check_ref_format(ref)) |
248 | return -1; | |
ca8db142 LT |
249 | filename = git_path("refs/%s", ref); |
250 | return read_ref(filename, sha1); | |
95fc7512 DB |
251 | } |
252 | ||
253 | static int lock_ref_file(const char *filename, const char *lock_filename, | |
254 | const unsigned char *old_sha1) | |
255 | { | |
256 | int fd = open(lock_filename, O_WRONLY | O_CREAT | O_EXCL, 0666); | |
257 | unsigned char current_sha1[20]; | |
258 | int retval; | |
259 | if (fd < 0) { | |
260 | return error("Couldn't open lock file for %s: %s", | |
261 | filename, strerror(errno)); | |
262 | } | |
ca8db142 | 263 | retval = read_ref(filename, current_sha1); |
95fc7512 DB |
264 | if (old_sha1) { |
265 | if (retval) { | |
266 | close(fd); | |
267 | unlink(lock_filename); | |
268 | return error("Could not read the current value of %s", | |
269 | filename); | |
270 | } | |
271 | if (memcmp(current_sha1, old_sha1, 20)) { | |
272 | close(fd); | |
273 | unlink(lock_filename); | |
274 | error("The current value of %s is %s", | |
275 | filename, sha1_to_hex(current_sha1)); | |
276 | return error("Expected %s", | |
277 | sha1_to_hex(old_sha1)); | |
278 | } | |
279 | } else { | |
280 | if (!retval) { | |
281 | close(fd); | |
282 | unlink(lock_filename); | |
283 | return error("Unexpectedly found a value of %s for %s", | |
284 | sha1_to_hex(current_sha1), filename); | |
285 | } | |
286 | } | |
287 | return fd; | |
288 | } | |
289 | ||
290 | int lock_ref_sha1(const char *ref, const unsigned char *old_sha1) | |
291 | { | |
292 | char *filename; | |
293 | char *lock_filename; | |
294 | int retval; | |
295 | if (check_ref_format(ref)) | |
296 | return -1; | |
297 | filename = ref_file_name(ref); | |
298 | lock_filename = ref_lock_file_name(ref); | |
299 | retval = lock_ref_file(filename, lock_filename, old_sha1); | |
300 | free(filename); | |
301 | free(lock_filename); | |
302 | return retval; | |
303 | } | |
304 | ||
305 | static int write_ref_file(const char *filename, | |
306 | const char *lock_filename, int fd, | |
307 | const unsigned char *sha1) | |
308 | { | |
309 | char *hex = sha1_to_hex(sha1); | |
310 | char term = '\n'; | |
311 | if (write(fd, hex, 40) < 40 || | |
312 | write(fd, &term, 1) < 1) { | |
313 | error("Couldn't write %s\n", filename); | |
314 | close(fd); | |
315 | return -1; | |
316 | } | |
317 | close(fd); | |
318 | rename(lock_filename, filename); | |
319 | return 0; | |
320 | } | |
321 | ||
322 | int write_ref_sha1(const char *ref, int fd, const unsigned char *sha1) | |
323 | { | |
324 | char *filename; | |
325 | char *lock_filename; | |
326 | int retval; | |
327 | if (fd < 0) | |
328 | return -1; | |
329 | if (check_ref_format(ref)) | |
330 | return -1; | |
331 | filename = ref_file_name(ref); | |
332 | lock_filename = ref_lock_file_name(ref); | |
333 | retval = write_ref_file(filename, lock_filename, fd, sha1); | |
334 | free(filename); | |
335 | free(lock_filename); | |
336 | return retval; | |
337 | } | |
338 | ||
03feddd6 JH |
339 | /* |
340 | * Make sure "ref" is something reasonable to have under ".git/refs/"; | |
341 | * We do not like it if: | |
342 | * | |
343 | * - any path component of it begins with ".", or | |
344 | * - it has double dots "..", or | |
345 | * - it has ASCII control character, "~", "^", ":" or SP, anywhere, or | |
346 | * - it ends with a "/". | |
347 | */ | |
348 | ||
349 | static inline int bad_ref_char(int ch) | |
350 | { | |
351 | return (((unsigned) ch) <= ' ' || | |
352 | ch == '~' || ch == '^' || ch == ':'); | |
353 | } | |
354 | ||
95fc7512 DB |
355 | int check_ref_format(const char *ref) |
356 | { | |
03feddd6 JH |
357 | int ch, level; |
358 | const char *cp = ref; | |
359 | ||
360 | level = 0; | |
361 | while (1) { | |
362 | while ((ch = *cp++) == '/') | |
363 | ; /* tolerate duplicated slashes */ | |
364 | if (!ch) | |
365 | return -1; /* should not end with slashes */ | |
366 | ||
367 | /* we are at the beginning of the path component */ | |
368 | if (ch == '.' || bad_ref_char(ch)) | |
369 | return -1; | |
370 | ||
371 | /* scan the rest of the path component */ | |
372 | while ((ch = *cp++) != 0) { | |
373 | if (bad_ref_char(ch)) | |
374 | return -1; | |
375 | if (ch == '/') | |
376 | break; | |
377 | if (ch == '.' && *cp == '.') | |
378 | return -1; | |
379 | } | |
380 | level++; | |
381 | if (!ch) { | |
382 | if (level < 2) | |
383 | return -1; /* at least of form "heads/blah" */ | |
384 | return 0; | |
385 | } | |
386 | } | |
95fc7512 DB |
387 | } |
388 | ||
389 | int write_ref_sha1_unlocked(const char *ref, const unsigned char *sha1) | |
390 | { | |
391 | char *filename; | |
392 | char *lock_filename; | |
393 | int fd; | |
394 | int retval; | |
395 | if (check_ref_format(ref)) | |
396 | return -1; | |
397 | filename = ref_file_name(ref); | |
398 | lock_filename = ref_lock_file_name(ref); | |
399 | fd = open(lock_filename, O_WRONLY | O_CREAT | O_EXCL, 0666); | |
400 | if (fd < 0) { | |
401 | error("Writing %s", lock_filename); | |
402 | perror("Open"); | |
403 | } | |
404 | retval = write_ref_file(filename, lock_filename, fd, sha1); | |
405 | free(filename); | |
406 | free(lock_filename); | |
407 | return retval; | |
408 | } |