diff options
Diffstat (limited to 'symlinks.c')
| -rw-r--r-- | symlinks.c | 153 |
1 files changed, 109 insertions, 44 deletions
@@ -1,51 +1,54 @@ #include "cache.h" -static struct cache_def { - char path[PATH_MAX + 1]; - int len; - int flags; - int track_flags; - int prefix_len_stat_func; -} cache; - /* * Returns the length (on a path component basis) of the longest - * common prefix match of 'name' and the cached path string. + * common prefix match of 'name_a' and 'name_b'. */ -static inline int longest_match_lstat_cache(int len, const char *name, - int *previous_slash) +static int longest_path_match(const char *name_a, int len_a, + const char *name_b, int len_b, + int *previous_slash) { int max_len, match_len = 0, match_len_prev = 0, i = 0; - max_len = len < cache.len ? len : cache.len; - while (i < max_len && name[i] == cache.path[i]) { - if (name[i] == '/') { + max_len = len_a < len_b ? len_a : len_b; + while (i < max_len && name_a[i] == name_b[i]) { + if (name_a[i] == '/') { match_len_prev = match_len; match_len = i; } i++; } - /* Is the cached path string a substring of 'name'? */ - if (i == cache.len && cache.len < len && name[cache.len] == '/') { - match_len_prev = match_len; - match_len = cache.len; - /* Is 'name' a substring of the cached path string? */ - } else if ((i == len && len < cache.len && cache.path[len] == '/') || - (i == len && len == cache.len)) { + /* + * Is 'name_b' a substring of 'name_a', the other way around, + * or is 'name_a' and 'name_b' the exact same string? + */ + if (i >= max_len && ((len_a > len_b && name_a[len_b] == '/') || + (len_a < len_b && name_b[len_a] == '/') || + (len_a == len_b))) { match_len_prev = match_len; - match_len = len; + match_len = i; } *previous_slash = match_len_prev; return match_len; } -static inline void reset_lstat_cache(int track_flags, int prefix_len_stat_func) +static struct cache_def { + char path[PATH_MAX + 1]; + int len; + int flags; + int track_flags; + int prefix_len_stat_func; +} cache; + +static inline void reset_lstat_cache(void) { cache.path[0] = '\0'; cache.len = 0; cache.flags = 0; - cache.track_flags = track_flags; - cache.prefix_len_stat_func = prefix_len_stat_func; + /* + * The track_flags and prefix_len_stat_func members is only + * set by the safeguard rule inside lstat_cache() + */ } #define FL_DIR (1 << 0) @@ -67,7 +70,7 @@ static inline void reset_lstat_cache(int track_flags, int prefix_len_stat_func) * of the prefix, where the cache should use the stat() function * instead of the lstat() function to test each path component. */ -static int lstat_cache(int len, const char *name, +static int lstat_cache(const char *name, int len, int track_flags, int prefix_len_stat_func) { int match_len, last_slash, last_slash_dir, previous_slash; @@ -77,11 +80,13 @@ static int lstat_cache(int len, const char *name, if (cache.track_flags != track_flags || cache.prefix_len_stat_func != prefix_len_stat_func) { /* - * As a safeguard we clear the cache if the values of - * track_flags and/or prefix_len_stat_func does not - * match with the last supplied values. + * As a safeguard rule we clear the cache if the + * values of track_flags and/or prefix_len_stat_func + * does not match with the last supplied values. */ - reset_lstat_cache(track_flags, prefix_len_stat_func); + reset_lstat_cache(); + cache.track_flags = track_flags; + cache.prefix_len_stat_func = prefix_len_stat_func; match_len = last_slash = 0; } else { /* @@ -89,7 +94,8 @@ static int lstat_cache(int len, const char *name, * the 2 "excluding" path types. */ match_len = last_slash = - longest_match_lstat_cache(len, name, &previous_slash); + longest_path_match(name, len, cache.path, cache.len, + &previous_slash); match_flags = cache.flags & track_flags & (FL_NOENT|FL_SYMLINK); if (match_flags && match_len == cache.len) return match_flags; @@ -153,7 +159,7 @@ static int lstat_cache(int len, const char *name, cache.path[last_slash] = '\0'; cache.len = last_slash; cache.flags = save_flags; - } else if (track_flags & FL_DIR && + } else if ((track_flags & FL_DIR) && last_slash_dir > 0 && last_slash_dir <= PATH_MAX) { /* * We have a separate test for the directory case, @@ -170,7 +176,7 @@ static int lstat_cache(int len, const char *name, cache.len = last_slash_dir; cache.flags = FL_DIR; } else { - reset_lstat_cache(track_flags, prefix_len_stat_func); + reset_lstat_cache(); } return ret_flags; } @@ -179,19 +185,19 @@ static int lstat_cache(int len, const char *name, * Invalidate the given 'name' from the cache, if 'name' matches * completely with the cache. */ -void invalidate_lstat_cache(int len, const char *name) +void invalidate_lstat_cache(const char *name, int len) { int match_len, previous_slash; - match_len = longest_match_lstat_cache(len, name, &previous_slash); + match_len = longest_path_match(name, len, cache.path, cache.len, + &previous_slash); if (len == match_len) { if ((cache.track_flags & FL_DIR) && previous_slash > 0) { cache.path[previous_slash] = '\0'; cache.len = previous_slash; cache.flags = FL_DIR; } else - reset_lstat_cache(cache.track_flags, - cache.prefix_len_stat_func); + reset_lstat_cache(); } } @@ -200,7 +206,7 @@ void invalidate_lstat_cache(int len, const char *name) */ void clear_lstat_cache(void) { - reset_lstat_cache(0, 0); + reset_lstat_cache(); } #define USE_ONLY_LSTAT 0 @@ -208,9 +214,9 @@ void clear_lstat_cache(void) /* * Return non-zero if path 'name' has a leading symlink component */ -int has_symlink_leading_path(int len, const char *name) +int has_symlink_leading_path(const char *name, int len) { - return lstat_cache(len, name, + return lstat_cache(name, len, FL_SYMLINK|FL_DIR, USE_ONLY_LSTAT) & FL_SYMLINK; } @@ -219,9 +225,9 @@ int has_symlink_leading_path(int len, const char *name) * Return non-zero if path 'name' has a leading symlink component or * if some leading path component does not exists. */ -int has_symlink_or_noent_leading_path(int len, const char *name) +int has_symlink_or_noent_leading_path(const char *name, int len) { - return lstat_cache(len, name, + return lstat_cache(name, len, FL_SYMLINK|FL_NOENT|FL_DIR, USE_ONLY_LSTAT) & (FL_SYMLINK|FL_NOENT); } @@ -233,9 +239,68 @@ int has_symlink_or_noent_leading_path(int len, const char *name) * 'prefix_len', thus we then allow for symlinks in the prefix part as * long as those points to real existing directories. */ -int has_dirs_only_path(int len, const char *name, int prefix_len) +int has_dirs_only_path(const char *name, int len, int prefix_len) { - return lstat_cache(len, name, + return lstat_cache(name, len, FL_DIR|FL_FULLPATH, prefix_len) & FL_DIR; } + +static struct removal_def { + char path[PATH_MAX]; + int len; +} removal; + +static void do_remove_scheduled_dirs(int new_len) +{ + while (removal.len > new_len) { + removal.path[removal.len] = '\0'; + if (rmdir(removal.path)) + break; + do { + removal.len--; + } while (removal.len > new_len && + removal.path[removal.len] != '/'); + } + removal.len = new_len; + return; +} + +void schedule_dir_for_removal(const char *name, int len) +{ + int match_len, last_slash, i, previous_slash; + + match_len = last_slash = i = + longest_path_match(name, len, removal.path, removal.len, + &previous_slash); + /* Find last slash inside 'name' */ + while (i < len) { + if (name[i] == '/') + last_slash = i; + i++; + } + + /* + * If we are about to go down the directory tree, we check if + * we must first go upwards the tree, such that we then can + * remove possible empty directories as we go upwards. + */ + if (match_len < last_slash && match_len < removal.len) + do_remove_scheduled_dirs(match_len); + /* + * If we go deeper down the directory tree, we only need to + * save the new path components as we go down. + */ + if (match_len < last_slash) { + memcpy(&removal.path[match_len], &name[match_len], + last_slash - match_len); + removal.len = last_slash; + } + return; +} + +void remove_scheduled_dirs(void) +{ + do_remove_scheduled_dirs(0); + return; +} |