4 * Returns the length (on a path component basis) of the longest
5 * common prefix match of 'name_a' and 'name_b'.
7 static int longest_path_match(const char *name_a
, int len_a
,
8 const char *name_b
, int len_b
,
11 int max_len
, match_len
= 0, match_len_prev
= 0, i
= 0;
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
] == '/') {
16 match_len_prev
= match_len
;
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?
25 if (i
>= max_len
&& ((len_a
> len_b
&& name_a
[len_b
] == '/') ||
26 (len_a
< len_b
&& name_b
[len_a
] == '/') ||
28 match_len_prev
= match_len
;
31 *previous_slash
= match_len_prev
;
35 static struct cache_def default_cache
;
37 static inline void reset_lstat_cache(struct cache_def
*cache
)
39 cache
->path
[0] = '\0';
43 * The track_flags and prefix_len_stat_func members is only
44 * set by the safeguard rule inside lstat_cache()
48 #define FL_DIR (1 << 0)
49 #define FL_NOENT (1 << 1)
50 #define FL_SYMLINK (1 << 2)
51 #define FL_LSTATERR (1 << 3)
52 #define FL_ERR (1 << 4)
53 #define FL_FULLPATH (1 << 5)
56 * Check if name 'name' of length 'len' has a symlink leading
57 * component, or if the directory exists and is real, or not.
59 * To speed up the check, some information is allowed to be cached.
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.
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.
67 static int lstat_cache(struct cache_def
*cache
, const char *name
, int len
,
68 int track_flags
, int prefix_len_stat_func
)
70 int match_len
, last_slash
, last_slash_dir
, previous_slash
;
71 int match_flags
, ret_flags
, save_flags
, max_len
, ret
;
74 if (cache
->track_flags
!= track_flags
||
75 cache
->prefix_len_stat_func
!= prefix_len_stat_func
) {
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.
81 reset_lstat_cache(cache
);
82 cache
->track_flags
= track_flags
;
83 cache
->prefix_len_stat_func
= prefix_len_stat_func
;
84 match_len
= last_slash
= 0;
87 * Check to see if we have a match from the cache for
88 * the 2 "excluding" path types.
90 match_len
= last_slash
=
91 longest_path_match(name
, len
, cache
->path
, cache
->len
,
93 match_flags
= cache
->flags
& track_flags
& (FL_NOENT
|FL_SYMLINK
);
94 if (match_flags
&& match_len
== cache
->len
)
97 * If we now have match_len > 0, we would know that
98 * the matched part will always be a directory.
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.
104 match_flags
= track_flags
& FL_DIR
;
105 if (match_flags
&& len
== match_len
)
110 * Okay, no match from the cache so far, so now we have to
111 * check the rest of the path components.
114 last_slash_dir
= last_slash
;
115 max_len
= len
< PATH_MAX
? len
: PATH_MAX
;
116 while (match_len
< max_len
) {
118 cache
->path
[match_len
] = name
[match_len
];
120 } while (match_len
< max_len
&& name
[match_len
] != '/');
121 if (match_len
>= max_len
&& !(track_flags
& FL_FULLPATH
))
123 last_slash
= match_len
;
124 cache
->path
[last_slash
] = '\0';
126 if (last_slash
<= prefix_len_stat_func
)
127 ret
= stat(cache
->path
, &st
);
129 ret
= lstat(cache
->path
, &st
);
132 ret_flags
= FL_LSTATERR
;
134 ret_flags
|= FL_NOENT
;
135 } else if (S_ISDIR(st
.st_mode
)) {
136 last_slash_dir
= last_slash
;
138 } else if (S_ISLNK(st
.st_mode
)) {
139 ret_flags
= FL_SYMLINK
;
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
151 save_flags
= ret_flags
& track_flags
& (FL_NOENT
|FL_SYMLINK
);
152 if (save_flags
&& last_slash
> 0 && last_slash
<= PATH_MAX
) {
153 cache
->path
[last_slash
] = '\0';
154 cache
->len
= last_slash
;
155 cache
->flags
= save_flags
;
156 } else if ((track_flags
& FL_DIR
) &&
157 last_slash_dir
> 0 && last_slash_dir
<= PATH_MAX
) {
159 * We have a separate test for the directory case,
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.
165 * But if we are allowed to track real directories, we
166 * can still cache the path components before the last
167 * one (the found symlink or non-existing component).
169 cache
->path
[last_slash_dir
] = '\0';
170 cache
->len
= last_slash_dir
;
171 cache
->flags
= FL_DIR
;
173 reset_lstat_cache(cache
);
179 * Invalidate the given 'name' from the cache, if 'name' matches
180 * completely with the cache.
182 void invalidate_lstat_cache(const char *name
, int len
)
184 int match_len
, previous_slash
;
185 struct cache_def
*cache
= &default_cache
; /* FIXME */
187 match_len
= longest_path_match(name
, len
, cache
->path
, cache
->len
,
189 if (len
== match_len
) {
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
;
195 reset_lstat_cache(cache
);
201 * Completely clear the contents of the cache
203 void clear_lstat_cache(void)
205 struct cache_def
*cache
= &default_cache
; /* FIXME */
206 reset_lstat_cache(cache
);
209 #define USE_ONLY_LSTAT 0
212 * Return non-zero if path 'name' has a leading symlink component
214 int threaded_has_symlink_leading_path(struct cache_def
*cache
, const char *name
, int len
)
216 return lstat_cache(cache
, name
, len
, FL_SYMLINK
|FL_DIR
, USE_ONLY_LSTAT
) & FL_SYMLINK
;
220 * Return non-zero if path 'name' has a leading symlink component
222 int has_symlink_leading_path(const char *name
, int len
)
224 return threaded_has_symlink_leading_path(&default_cache
, name
, len
);
228 * Return non-zero if path 'name' has a leading symlink component or
229 * if some leading path component does not exists.
231 int has_symlink_or_noent_leading_path(const char *name
, int len
)
233 struct cache_def
*cache
= &default_cache
; /* FIXME */
234 return lstat_cache(cache
, name
, len
,
235 FL_SYMLINK
|FL_NOENT
|FL_DIR
, USE_ONLY_LSTAT
) &
236 (FL_SYMLINK
|FL_NOENT
);
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.
246 int has_dirs_only_path(const char *name
, int len
, int prefix_len
)
248 struct cache_def
*cache
= &default_cache
; /* FIXME */
249 return lstat_cache(cache
, name
, len
,
250 FL_DIR
|FL_FULLPATH
, prefix_len
) &
254 static struct removal_def
{
259 static void do_remove_scheduled_dirs(int new_len
)
261 while (removal
.len
> new_len
) {
262 removal
.path
[removal
.len
] = '\0';
263 if (rmdir(removal
.path
))
267 } while (removal
.len
> new_len
&&
268 removal
.path
[removal
.len
] != '/');
270 removal
.len
= new_len
;
273 void schedule_dir_for_removal(const char *name
, int len
)
275 int match_len
, last_slash
, i
, previous_slash
;
277 match_len
= last_slash
= i
=
278 longest_path_match(name
, len
, removal
.path
, removal
.len
,
280 /* Find last slash inside 'name' */
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.
292 if (match_len
< last_slash
&& match_len
< removal
.len
)
293 do_remove_scheduled_dirs(match_len
);
295 * If we go deeper down the directory tree, we only need to
296 * save the new path components as we go down.
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
;
305 void remove_scheduled_dirs(void)
307 do_remove_scheduled_dirs(0);