+ /* If the ownership might change, or if the directory will be
+ writeable to other users and its special mode bits may
+ change after the directory is created, create it with
+ more restrictive permissions at first, so unauthorized
+ users cannot nip in before the directory is ready. */
+ bool keep_owner = owner == (uid_t) -1 && group == (gid_t) -1;
+ bool keep_special_mode_bits =
+ ((mode_bits & (S_ISUID | S_ISGID)) | (mode & S_ISVTX)) == 0;
+ mode_t mkdir_mode = mode;
+ if (! keep_owner)
+ mkdir_mode &= ~ (S_IRWXG | S_IRWXO);
+ else if (! keep_special_mode_bits)
+ mkdir_mode &= ~ (S_IWGRP | S_IWOTH);
+
+ if (mkdir (dir + prefix_len, mkdir_mode) == 0)
+ {
+ announce (dir, options);
+ preserve_existing = keep_owner & keep_special_mode_bits;
+ savewd_chdir_options |=
+ (SAVEWD_CHDIR_NOFOLLOW
+ | (mode & S_IRUSR ? SAVEWD_CHDIR_READABLE : 0));
+ }
+ else
+ {
+ mkdir_errno = errno;
+ mkdir_mode = -1;
+ }
+
+ if (preserve_existing)
+ {
+ struct stat st;
+ if (mkdir_errno == 0
+ || (mkdir_errno != ENOENT && make_ancestor
+ && stat (dir + prefix_len, &st) == 0
+ && S_ISDIR (st.st_mode)))
+ return true;
+ }
+ else
+ {
+ int open_result[2];
+ int chdir_result =
+ savewd_chdir (wd, dir + prefix_len,
+ savewd_chdir_options, open_result);
+ if (chdir_result < -1)
+ return true;
+ else
+ {
+ bool chdir_ok = (chdir_result == 0);
+ int chdir_errno = errno;
+ int fd = open_result[0];
+ bool chdir_failed_unexpectedly =
+ (mkdir_errno == 0
+ && ((! chdir_ok && (mode & S_IXUSR))
+ || (fd < 0 && (mode & S_IRUSR))));
+
+ if (chdir_failed_unexpectedly)
+ {
+ /* No need to save errno here; it's irrelevant. */
+ if (0 <= fd)
+ close (fd);
+ }
+ else
+ {
+ char const *subdir = (chdir_ok ? "." : dir + prefix_len);
+ if (dirchownmod (fd, subdir, mkdir_mode, owner, group,
+ mode, mode_bits)
+ == 0)
+ return true;
+ }
+
+ if (mkdir_errno == 0
+ || (mkdir_errno != ENOENT && make_ancestor
+ && errno != ENOTDIR))
+ {
+ error (0,
+ (! chdir_failed_unexpectedly ? errno
+ : ! chdir_ok && (mode & S_IXUSR) ? chdir_errno
+ : open_result[1]),
+ _(keep_owner
+ ? "cannot change permissions of %s"
+ : "cannot change owner and permissions of %s"),
+ quote (dir));
+ return false;
+ }
+ }
+ }