freshlybakedca.ke
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1#define DISABLE_SIGN_COMPARE_WARNINGS
2
3#include "git-compat-util.h"
4#include "gettext.h"
5#include "setup.h"
6#include "symlinks.h"
7
8static int threaded_check_leading_path(struct cache_def *cache, const char *name,
9 int len, int warn_on_lstat_err);
10static int threaded_has_dirs_only_path(struct cache_def *cache, const char *name, int len, int prefix_len);
11
12/*
13 * Returns the length (on a path component basis) of the longest
14 * common prefix match of 'name_a' and 'name_b'.
15 */
16static int longest_path_match(const char *name_a, int len_a,
17 const char *name_b, int len_b,
18 int *previous_slash)
19{
20 int max_len, match_len = 0, match_len_prev = 0, i = 0;
21
22 max_len = len_a < len_b ? len_a : len_b;
23 while (i < max_len && name_a[i] == name_b[i]) {
24 if (name_a[i] == '/') {
25 match_len_prev = match_len;
26 match_len = i;
27 }
28 i++;
29 }
30 /*
31 * Is 'name_b' a substring of 'name_a', the other way around,
32 * or is 'name_a' and 'name_b' the exact same string?
33 */
34 if (i >= max_len && ((len_a > len_b && name_a[len_b] == '/') ||
35 (len_a < len_b && name_b[len_a] == '/') ||
36 (len_a == len_b))) {
37 match_len_prev = match_len;
38 match_len = i;
39 }
40 *previous_slash = match_len_prev;
41 return match_len;
42}
43
44static struct cache_def default_cache = CACHE_DEF_INIT;
45
46static inline void reset_lstat_cache(struct cache_def *cache)
47{
48 strbuf_reset(&cache->path);
49 cache->flags = 0;
50 /*
51 * The track_flags and prefix_len_stat_func members is only
52 * set by the safeguard rule inside lstat_cache()
53 */
54}
55
56#define FL_DIR (1 << 0)
57#define FL_NOENT (1 << 1)
58#define FL_SYMLINK (1 << 2)
59#define FL_LSTATERR (1 << 3)
60#define FL_ERR (1 << 4)
61#define FL_FULLPATH (1 << 5)
62
63/*
64 * Check if name 'name' of length 'len' has a symlink leading
65 * component, or if the directory exists and is real, or not.
66 *
67 * To speed up the check, some information is allowed to be cached.
68 * This can be indicated by the 'track_flags' argument, which also can
69 * be used to indicate that we should check the full path.
70 *
71 * The 'prefix_len_stat_func' parameter can be used to set the length
72 * of the prefix, where the cache should use the stat() function
73 * instead of the lstat() function to test each path component.
74 */
75static int lstat_cache_matchlen(struct cache_def *cache,
76 const char *name, int len,
77 int *ret_flags, int track_flags,
78 int prefix_len_stat_func)
79{
80 int match_len, last_slash, last_slash_dir, previous_slash;
81 int save_flags, ret, saved_errno = 0;
82 struct stat st;
83
84 if (cache->track_flags != track_flags ||
85 cache->prefix_len_stat_func != prefix_len_stat_func) {
86 /*
87 * As a safeguard rule we clear the cache if the
88 * values of track_flags and/or prefix_len_stat_func
89 * does not match with the last supplied values.
90 */
91 reset_lstat_cache(cache);
92 cache->track_flags = track_flags;
93 cache->prefix_len_stat_func = prefix_len_stat_func;
94 match_len = last_slash = 0;
95 } else {
96 /*
97 * Check to see if we have a match from the cache for
98 * the 2 "excluding" path types.
99 */
100 match_len = last_slash =
101 longest_path_match(name, len, cache->path.buf,
102 cache->path.len, &previous_slash);
103 *ret_flags = cache->flags & track_flags & (FL_NOENT|FL_SYMLINK);
104
105 if (!(track_flags & FL_FULLPATH) && match_len == len)
106 match_len = last_slash = previous_slash;
107
108 if (*ret_flags && match_len == cache->path.len)
109 return match_len;
110 /*
111 * If we now have match_len > 0, we would know that
112 * the matched part will always be a directory.
113 *
114 * Also, if we are tracking directories and 'name' is
115 * a substring of the cache on a path component basis,
116 * we can return immediately.
117 */
118 *ret_flags = track_flags & FL_DIR;
119 if (*ret_flags && len == match_len)
120 return match_len;
121 }
122
123 /*
124 * Okay, no match from the cache so far, so now we have to
125 * check the rest of the path components.
126 */
127 *ret_flags = FL_DIR;
128 last_slash_dir = last_slash;
129 if (len > cache->path.len)
130 strbuf_grow(&cache->path, len - cache->path.len);
131 while (match_len < len) {
132 do {
133 cache->path.buf[match_len] = name[match_len];
134 match_len++;
135 } while (match_len < len && name[match_len] != '/');
136 if (match_len >= len && !(track_flags & FL_FULLPATH))
137 break;
138 last_slash = match_len;
139 cache->path.buf[last_slash] = '\0';
140
141 if (last_slash <= prefix_len_stat_func)
142 ret = stat(cache->path.buf, &st);
143 else
144 ret = lstat(cache->path.buf, &st);
145
146 if (ret) {
147 *ret_flags = FL_LSTATERR;
148 saved_errno = errno;
149 if (errno == ENOENT)
150 *ret_flags |= FL_NOENT;
151 } else if (S_ISDIR(st.st_mode)) {
152 last_slash_dir = last_slash;
153 continue;
154 } else if (S_ISLNK(st.st_mode)) {
155 *ret_flags = FL_SYMLINK;
156 } else {
157 *ret_flags = FL_ERR;
158 }
159 break;
160 }
161
162 /*
163 * At the end update the cache. Note that max 3 different
164 * path types, FL_NOENT, FL_SYMLINK and FL_DIR, can be cached
165 * for the moment!
166 */
167 save_flags = *ret_flags & track_flags & (FL_NOENT|FL_SYMLINK);
168 if (save_flags && last_slash > 0) {
169 cache->path.buf[last_slash] = '\0';
170 cache->path.len = last_slash;
171 cache->flags = save_flags;
172 } else if ((track_flags & FL_DIR) && last_slash_dir > 0) {
173 /*
174 * We have a separate test for the directory case,
175 * since it could be that we have found a symlink or a
176 * non-existing directory and the track_flags says
177 * that we cannot cache this fact, so the cache would
178 * then have been left empty in this case.
179 *
180 * But if we are allowed to track real directories, we
181 * can still cache the path components before the last
182 * one (the found symlink or non-existing component).
183 */
184 cache->path.buf[last_slash_dir] = '\0';
185 cache->path.len = last_slash_dir;
186 cache->flags = FL_DIR;
187 } else {
188 reset_lstat_cache(cache);
189 }
190 if (saved_errno)
191 errno = saved_errno;
192 return match_len;
193}
194
195static int lstat_cache(struct cache_def *cache, const char *name, int len,
196 int track_flags, int prefix_len_stat_func)
197{
198 int flags;
199 (void)lstat_cache_matchlen(cache, name, len, &flags, track_flags,
200 prefix_len_stat_func);
201 return flags;
202}
203
204#define USE_ONLY_LSTAT 0
205
206/*
207 * Return non-zero if path 'name' has a leading symlink component
208 */
209int threaded_has_symlink_leading_path(struct cache_def *cache, const char *name, int len)
210{
211 return lstat_cache(cache, name, len, FL_SYMLINK|FL_DIR, USE_ONLY_LSTAT) & FL_SYMLINK;
212}
213
214int has_symlink_leading_path(const char *name, int len)
215{
216 return threaded_has_symlink_leading_path(&default_cache, name, len);
217}
218
219int check_leading_path(const char *name, int len, int warn_on_lstat_err)
220{
221 return threaded_check_leading_path(&default_cache, name, len,
222 warn_on_lstat_err);
223}
224
225/*
226 * Return zero if some leading path component of 'name' does not exist.
227 *
228 * Return -1 if leading path exists and is a directory.
229 *
230 * Return the length of a leading component if it either exists but it's not a
231 * directory, or if we were unable to lstat() it. If warn_on_lstat_err is true,
232 * also emit a warning for this error.
233 */
234static int threaded_check_leading_path(struct cache_def *cache, const char *name,
235 int len, int warn_on_lstat_err)
236{
237 int flags;
238 int match_len = lstat_cache_matchlen(cache, name, len, &flags,
239 FL_SYMLINK|FL_NOENT|FL_DIR, USE_ONLY_LSTAT);
240 int saved_errno = errno;
241
242 if (flags & FL_NOENT)
243 return 0;
244 else if (flags & FL_DIR)
245 return -1;
246 if (warn_on_lstat_err && (flags & FL_LSTATERR)) {
247 char *path = xmemdupz(name, match_len);
248 errno = saved_errno;
249 warning_errno(_("failed to lstat '%s'"), path);
250 free(path);
251 }
252 return match_len;
253}
254
255int has_dirs_only_path(const char *name, int len, int prefix_len)
256{
257 return threaded_has_dirs_only_path(&default_cache, name, len, prefix_len);
258}
259
260/*
261 * Return non-zero if all path components of 'name' exists as a
262 * directory. If prefix_len > 0, we will test with the stat()
263 * function instead of the lstat() function for a prefix length of
264 * 'prefix_len', thus we then allow for symlinks in the prefix part as
265 * long as those points to real existing directories.
266 */
267static int threaded_has_dirs_only_path(struct cache_def *cache, const char *name, int len, int prefix_len)
268{
269 /*
270 * Note: this function is used by the checkout machinery, which also
271 * takes care to properly reset the cache when it performs an operation
272 * that would leave the cache outdated. If this function starts caching
273 * anything else besides FL_DIR, remember to also invalidate the cache
274 * when creating or deleting paths that might be in the cache.
275 */
276 return lstat_cache(cache, name, len,
277 FL_DIR|FL_FULLPATH, prefix_len) &
278 FL_DIR;
279}
280
281static struct strbuf removal = STRBUF_INIT;
282
283static void do_remove_scheduled_dirs(int new_len)
284{
285 while (removal.len > new_len) {
286 removal.buf[removal.len] = '\0';
287 if ((startup_info->original_cwd &&
288 !strcmp(removal.buf, startup_info->original_cwd)) ||
289 rmdir(removal.buf))
290 break;
291 do {
292 removal.len--;
293 } while (removal.len > new_len &&
294 removal.buf[removal.len] != '/');
295 }
296 removal.len = new_len;
297}
298
299void schedule_dir_for_removal(const char *name, int len)
300{
301 int match_len, last_slash, i, previous_slash;
302
303 if (startup_info->original_cwd &&
304 !strcmp(name, startup_info->original_cwd))
305 return; /* Do not remove the current working directory */
306
307 match_len = last_slash = i =
308 longest_path_match(name, len, removal.buf, removal.len,
309 &previous_slash);
310 /* Find last slash inside 'name' */
311 while (i < len) {
312 if (name[i] == '/')
313 last_slash = i;
314 i++;
315 }
316
317 /*
318 * If we are about to go down the directory tree, we check if
319 * we must first go upwards the tree, such that we then can
320 * remove possible empty directories as we go upwards.
321 */
322 if (match_len < last_slash && match_len < removal.len)
323 do_remove_scheduled_dirs(match_len);
324 /*
325 * If we go deeper down the directory tree, we only need to
326 * save the new path components as we go down.
327 */
328 if (match_len < last_slash)
329 strbuf_add(&removal, &name[match_len], last_slash - match_len);
330}
331
332void remove_scheduled_dirs(void)
333{
334 do_remove_scheduled_dirs(0);
335}
336
337void invalidate_lstat_cache(void)
338{
339 reset_lstat_cache(&default_cache);
340}
341
342#undef rmdir
343int lstat_cache_aware_rmdir(const char *path)
344{
345 /* Any change in this function must be made also in `mingw_rmdir()` */
346 int ret = rmdir(path);
347
348 if (!ret)
349 invalidate_lstat_cache();
350
351 return ret;
352}