This new flag controls whether to consider a problem if the referenced path
doesn't actually exist. If specified it's OK if the final file doesn't exist.
Note that this permits one or more final components of the path not to exist,
but these must not contain "../" for safety reasons (or, to be extra safe,
neither "./" and a couple of others, i.e. what path_is_safe() permits).
This new flag is useful when resolving paths before issuing an mkdir() or
open(O_CREAT) on a path, as it permits that the file or directory is created
later.
The return code of chase_symlinks() is changed to return 1 if the file exists,
and 0 if it doesn't. The latter is only returned in case CHASE_NON_EXISTING is
set.
_cleanup_free_ char *buffer = NULL, *done = NULL, *root = NULL;
_cleanup_close_ int fd = -1;
unsigned max_follow = 32; /* how many symlinks to follow before giving up and returning ELOOP */
_cleanup_free_ char *buffer = NULL, *done = NULL, *root = NULL;
_cleanup_close_ int fd = -1;
unsigned max_follow = 32; /* how many symlinks to follow before giving up and returning ELOOP */
/* Otherwise let's see what this is. */
child = openat(fd, first + n, O_CLOEXEC|O_NOFOLLOW|O_PATH);
/* Otherwise let's see what this is. */
child = openat(fd, first + n, O_CLOEXEC|O_NOFOLLOW|O_PATH);
+ if (child < 0) {
+
+ if (errno == ENOENT &&
+ (flags & CHASE_NON_EXISTING) &&
+ (isempty(todo) || path_is_safe(todo))) {
+
+ /* If CHASE_NON_EXISTING is set, and the path does not exist, then that's OK, return
+ * what we got so far. But don't allow this if the remaining path contains "../ or "./"
+ * or something else weird. */
+
+ if (!strextend(&done, first, todo, NULL))
+ return -ENOMEM;
+
+ exists = false;
+ break;
+ }
+
if (fstat(child, &st) < 0)
return -errno;
if (fstat(child, &st) < 0)
return -errno;
*ret = done;
done = NULL;
*ret = done;
done = NULL;
#endif // 0
enum {
CHASE_PREFIX_ROOT = 1, /* If set, the specified path will be prefixed by the specified root before beginning the iteration */
#endif // 0
enum {
CHASE_PREFIX_ROOT = 1, /* If set, the specified path will be prefixed by the specified root before beginning the iteration */
+ CHASE_NON_EXISTING = 2, /* If set, it's OK if the path doesn't actually exist. */
};
int chase_symlinks(const char *path_with_prefix, const char *root, unsigned flags, char **ret);
};
int chase_symlinks(const char *path_with_prefix, const char *root, unsigned flags, char **ret);