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f859c846 JH |
1 | #include "cache.h" |
2 | ||
92604b46 KB |
3 | /* |
4 | * Returns the length (on a path component basis) of the longest | |
148bc06b | 5 | * common prefix match of 'name_a' and 'name_b'. |
92604b46 | 6 | */ |
148bc06b KB |
7 | static int longest_path_match(const char *name_a, int len_a, |
8 | const char *name_b, int len_b, | |
9 | int *previous_slash) | |
c40641b7 | 10 | { |
aeabab5c | 11 | int max_len, match_len = 0, match_len_prev = 0, i = 0; |
92604b46 | 12 | |
148bc06b KB |
13 | max_len = len_a < len_b ? len_a : len_b; |
14 | while (i < max_len && name_a[i] == name_b[i]) { | |
15 | if (name_a[i] == '/') { | |
aeabab5c | 16 | match_len_prev = match_len; |
92604b46 | 17 | match_len = i; |
aeabab5c | 18 | } |
92604b46 KB |
19 | i++; |
20 | } | |
60b458b7 | 21 | /* |
148bc06b KB |
22 | * Is 'name_b' a substring of 'name_a', the other way around, |
23 | * or is 'name_a' and 'name_b' the exact same string? | |
60b458b7 | 24 | */ |
148bc06b KB |
25 | if (i >= max_len && ((len_a > len_b && name_a[len_b] == '/') || |
26 | (len_a < len_b && name_b[len_a] == '/') || | |
27 | (len_a == len_b))) { | |
aeabab5c | 28 | match_len_prev = match_len; |
60b458b7 | 29 | match_len = i; |
aeabab5c KB |
30 | } |
31 | *previous_slash = match_len_prev; | |
92604b46 | 32 | return match_len; |
c40641b7 LT |
33 | } |
34 | ||
b9fd2846 | 35 | static struct cache_def default_cache; |
148bc06b | 36 | |
867f72bf | 37 | static inline void reset_lstat_cache(struct cache_def *cache) |
c40641b7 | 38 | { |
867f72bf LT |
39 | cache->path[0] = '\0'; |
40 | cache->len = 0; | |
41 | cache->flags = 0; | |
60b458b7 KB |
42 | /* |
43 | * The track_flags and prefix_len_stat_func members is only | |
44 | * set by the safeguard rule inside lstat_cache() | |
45 | */ | |
c40641b7 LT |
46 | } |
47 | ||
92604b46 | 48 | #define FL_DIR (1 << 0) |
09c93066 KB |
49 | #define FL_NOENT (1 << 1) |
50 | #define FL_SYMLINK (1 << 2) | |
51 | #define FL_LSTATERR (1 << 3) | |
52 | #define FL_ERR (1 << 4) | |
bad4a54f | 53 | #define FL_FULLPATH (1 << 5) |
92604b46 KB |
54 | |
55 | /* | |
56 | * Check if name 'name' of length 'len' has a symlink leading | |
09c93066 | 57 | * component, or if the directory exists and is real, or not. |
92604b46 KB |
58 | * |
59 | * To speed up the check, some information is allowed to be cached. | |
bad4a54f KB |
60 | * This can be indicated by the 'track_flags' argument, which also can |
61 | * be used to indicate that we should check the full path. | |
62 | * | |
63 | * The 'prefix_len_stat_func' parameter can be used to set the length | |
64 | * of the prefix, where the cache should use the stat() function | |
65 | * instead of the lstat() function to test each path component. | |
92604b46 | 66 | */ |
867f72bf | 67 | static int lstat_cache(struct cache_def *cache, const char *name, int len, |
bad4a54f | 68 | int track_flags, int prefix_len_stat_func) |
c40641b7 | 69 | { |
aeabab5c | 70 | int match_len, last_slash, last_slash_dir, previous_slash; |
bad4a54f | 71 | int match_flags, ret_flags, save_flags, max_len, ret; |
c40641b7 | 72 | struct stat st; |
f859c846 | 73 | |
867f72bf LT |
74 | if (cache->track_flags != track_flags || |
75 | cache->prefix_len_stat_func != prefix_len_stat_func) { | |
09c93066 | 76 | /* |
60b458b7 KB |
77 | * As a safeguard rule we clear the cache if the |
78 | * values of track_flags and/or prefix_len_stat_func | |
79 | * does not match with the last supplied values. | |
09c93066 | 80 | */ |
867f72bf LT |
81 | reset_lstat_cache(cache); |
82 | cache->track_flags = track_flags; | |
83 | cache->prefix_len_stat_func = prefix_len_stat_func; | |
09c93066 KB |
84 | match_len = last_slash = 0; |
85 | } else { | |
86 | /* | |
87 | * Check to see if we have a match from the cache for | |
88 | * the 2 "excluding" path types. | |
89 | */ | |
aeabab5c | 90 | match_len = last_slash = |
867f72bf | 91 | longest_path_match(name, len, cache->path, cache->len, |
148bc06b | 92 | &previous_slash); |
867f72bf LT |
93 | match_flags = cache->flags & track_flags & (FL_NOENT|FL_SYMLINK); |
94 | if (match_flags && match_len == cache->len) | |
09c93066 KB |
95 | return match_flags; |
96 | /* | |
97 | * If we now have match_len > 0, we would know that | |
98 | * the matched part will always be a directory. | |
99 | * | |
100 | * Also, if we are tracking directories and 'name' is | |
101 | * a substring of the cache on a path component basis, | |
102 | * we can return immediately. | |
103 | */ | |
104 | match_flags = track_flags & FL_DIR; | |
105 | if (match_flags && len == match_len) | |
106 | return match_flags; | |
107 | } | |
c40641b7 | 108 | |
92604b46 KB |
109 | /* |
110 | * Okay, no match from the cache so far, so now we have to | |
111 | * check the rest of the path components. | |
112 | */ | |
113 | ret_flags = FL_DIR; | |
114 | last_slash_dir = last_slash; | |
115 | max_len = len < PATH_MAX ? len : PATH_MAX; | |
116 | while (match_len < max_len) { | |
117 | do { | |
867f72bf | 118 | cache->path[match_len] = name[match_len]; |
92604b46 KB |
119 | match_len++; |
120 | } while (match_len < max_len && name[match_len] != '/'); | |
bad4a54f | 121 | if (match_len >= max_len && !(track_flags & FL_FULLPATH)) |
92604b46 KB |
122 | break; |
123 | last_slash = match_len; | |
867f72bf | 124 | cache->path[last_slash] = '\0'; |
f859c846 | 125 | |
bad4a54f | 126 | if (last_slash <= prefix_len_stat_func) |
867f72bf | 127 | ret = stat(cache->path, &st); |
bad4a54f | 128 | else |
867f72bf | 129 | ret = lstat(cache->path, &st); |
bad4a54f KB |
130 | |
131 | if (ret) { | |
92604b46 | 132 | ret_flags = FL_LSTATERR; |
09c93066 KB |
133 | if (errno == ENOENT) |
134 | ret_flags |= FL_NOENT; | |
92604b46 KB |
135 | } else if (S_ISDIR(st.st_mode)) { |
136 | last_slash_dir = last_slash; | |
c40641b7 | 137 | continue; |
92604b46 KB |
138 | } else if (S_ISLNK(st.st_mode)) { |
139 | ret_flags = FL_SYMLINK; | |
140 | } else { | |
141 | ret_flags = FL_ERR; | |
f859c846 | 142 | } |
c40641b7 | 143 | break; |
f859c846 | 144 | } |
92604b46 KB |
145 | |
146 | /* | |
09c93066 KB |
147 | * At the end update the cache. Note that max 3 different |
148 | * path types, FL_NOENT, FL_SYMLINK and FL_DIR, can be cached | |
149 | * for the moment! | |
92604b46 | 150 | */ |
09c93066 | 151 | save_flags = ret_flags & track_flags & (FL_NOENT|FL_SYMLINK); |
bad4a54f | 152 | if (save_flags && last_slash > 0 && last_slash <= PATH_MAX) { |
867f72bf LT |
153 | cache->path[last_slash] = '\0'; |
154 | cache->len = last_slash; | |
155 | cache->flags = save_flags; | |
60b458b7 | 156 | } else if ((track_flags & FL_DIR) && |
bad4a54f | 157 | last_slash_dir > 0 && last_slash_dir <= PATH_MAX) { |
92604b46 KB |
158 | /* |
159 | * We have a separate test for the directory case, | |
09c93066 KB |
160 | * since it could be that we have found a symlink or a |
161 | * non-existing directory and the track_flags says | |
162 | * that we cannot cache this fact, so the cache would | |
163 | * then have been left empty in this case. | |
92604b46 KB |
164 | * |
165 | * But if we are allowed to track real directories, we | |
166 | * can still cache the path components before the last | |
09c93066 | 167 | * one (the found symlink or non-existing component). |
92604b46 | 168 | */ |
867f72bf LT |
169 | cache->path[last_slash_dir] = '\0'; |
170 | cache->len = last_slash_dir; | |
171 | cache->flags = FL_DIR; | |
92604b46 | 172 | } else { |
867f72bf | 173 | reset_lstat_cache(cache); |
92604b46 KB |
174 | } |
175 | return ret_flags; | |
176 | } | |
177 | ||
aeabab5c KB |
178 | /* |
179 | * Invalidate the given 'name' from the cache, if 'name' matches | |
180 | * completely with the cache. | |
181 | */ | |
57199892 | 182 | void invalidate_lstat_cache(const char *name, int len) |
aeabab5c KB |
183 | { |
184 | int match_len, previous_slash; | |
867f72bf | 185 | struct cache_def *cache = &default_cache; /* FIXME */ |
aeabab5c | 186 | |
867f72bf | 187 | match_len = longest_path_match(name, len, cache->path, cache->len, |
148bc06b | 188 | &previous_slash); |
aeabab5c | 189 | if (len == match_len) { |
867f72bf LT |
190 | if ((cache->track_flags & FL_DIR) && previous_slash > 0) { |
191 | cache->path[previous_slash] = '\0'; | |
192 | cache->len = previous_slash; | |
193 | cache->flags = FL_DIR; | |
cb319c36 | 194 | } else { |
867f72bf | 195 | reset_lstat_cache(cache); |
cb319c36 | 196 | } |
aeabab5c KB |
197 | } |
198 | } | |
199 | ||
bda6eb0d KB |
200 | /* |
201 | * Completely clear the contents of the cache | |
202 | */ | |
203 | void clear_lstat_cache(void) | |
204 | { | |
867f72bf LT |
205 | struct cache_def *cache = &default_cache; /* FIXME */ |
206 | reset_lstat_cache(cache); | |
bda6eb0d KB |
207 | } |
208 | ||
bad4a54f KB |
209 | #define USE_ONLY_LSTAT 0 |
210 | ||
b9fd2846 LT |
211 | /* |
212 | * Return non-zero if path 'name' has a leading symlink component | |
213 | */ | |
214 | int threaded_has_symlink_leading_path(struct cache_def *cache, const char *name, int len) | |
215 | { | |
216 | return lstat_cache(cache, name, len, FL_SYMLINK|FL_DIR, USE_ONLY_LSTAT) & FL_SYMLINK; | |
217 | } | |
218 | ||
92604b46 KB |
219 | /* |
220 | * Return non-zero if path 'name' has a leading symlink component | |
221 | */ | |
57199892 | 222 | int has_symlink_leading_path(const char *name, int len) |
92604b46 | 223 | { |
b9fd2846 | 224 | return threaded_has_symlink_leading_path(&default_cache, name, len); |
f859c846 | 225 | } |
09c93066 KB |
226 | |
227 | /* | |
228 | * Return non-zero if path 'name' has a leading symlink component or | |
229 | * if some leading path component does not exists. | |
230 | */ | |
57199892 | 231 | int has_symlink_or_noent_leading_path(const char *name, int len) |
09c93066 | 232 | { |
867f72bf LT |
233 | struct cache_def *cache = &default_cache; /* FIXME */ |
234 | return lstat_cache(cache, name, len, | |
bad4a54f | 235 | FL_SYMLINK|FL_NOENT|FL_DIR, USE_ONLY_LSTAT) & |
09c93066 KB |
236 | (FL_SYMLINK|FL_NOENT); |
237 | } | |
bad4a54f KB |
238 | |
239 | /* | |
240 | * Return non-zero if all path components of 'name' exists as a | |
241 | * directory. If prefix_len > 0, we will test with the stat() | |
242 | * function instead of the lstat() function for a prefix length of | |
243 | * 'prefix_len', thus we then allow for symlinks in the prefix part as | |
244 | * long as those points to real existing directories. | |
245 | */ | |
57199892 | 246 | int has_dirs_only_path(const char *name, int len, int prefix_len) |
bad4a54f | 247 | { |
867f72bf LT |
248 | struct cache_def *cache = &default_cache; /* FIXME */ |
249 | return lstat_cache(cache, name, len, | |
bad4a54f KB |
250 | FL_DIR|FL_FULLPATH, prefix_len) & |
251 | FL_DIR; | |
252 | } | |
78478927 KB |
253 | |
254 | static struct removal_def { | |
255 | char path[PATH_MAX]; | |
256 | int len; | |
257 | } removal; | |
258 | ||
259 | static void do_remove_scheduled_dirs(int new_len) | |
260 | { | |
261 | while (removal.len > new_len) { | |
262 | removal.path[removal.len] = '\0'; | |
263 | if (rmdir(removal.path)) | |
264 | break; | |
265 | do { | |
266 | removal.len--; | |
267 | } while (removal.len > new_len && | |
268 | removal.path[removal.len] != '/'); | |
269 | } | |
270 | removal.len = new_len; | |
78478927 KB |
271 | } |
272 | ||
273 | void schedule_dir_for_removal(const char *name, int len) | |
274 | { | |
275 | int match_len, last_slash, i, previous_slash; | |
276 | ||
277 | match_len = last_slash = i = | |
278 | longest_path_match(name, len, removal.path, removal.len, | |
279 | &previous_slash); | |
280 | /* Find last slash inside 'name' */ | |
281 | while (i < len) { | |
282 | if (name[i] == '/') | |
283 | last_slash = i; | |
284 | i++; | |
285 | } | |
286 | ||
287 | /* | |
288 | * If we are about to go down the directory tree, we check if | |
289 | * we must first go upwards the tree, such that we then can | |
290 | * remove possible empty directories as we go upwards. | |
291 | */ | |
292 | if (match_len < last_slash && match_len < removal.len) | |
293 | do_remove_scheduled_dirs(match_len); | |
294 | /* | |
295 | * If we go deeper down the directory tree, we only need to | |
296 | * save the new path components as we go down. | |
297 | */ | |
298 | if (match_len < last_slash) { | |
299 | memcpy(&removal.path[match_len], &name[match_len], | |
300 | last_slash - match_len); | |
301 | removal.len = last_slash; | |
302 | } | |
78478927 KB |
303 | } |
304 | ||
305 | void remove_scheduled_dirs(void) | |
306 | { | |
307 | do_remove_scheduled_dirs(0); | |
78478927 | 308 | } |