Function unlink_and_reopen

util1.c:323–352

Remove existing file @dest and reopen, creating a new file with @mode */

/* Remove existing file @dest and reopen, creating a new file with @mode */
static int unlink_and_reopen(const char *dest, mode_t mode)
{
	int ofd;

	if (robust_unlink(dest) && errno != ENOENT) {
		int save_errno = errno;
		rsyserr(FERROR_XFER, errno, "unlink %s", full_fname(dest));
		errno = save_errno;
		return -1;
	}

#ifdef SUPPORT_XATTRS
	if (preserve_xattrs)
		mode |= S_IWUSR;
#endif
	mode &= INITACCESSPERMS;
	/* Use do_open_at so the create/truncate goes through a secure
	 * parent dirfd in the daemon-no-chroot deployment. Otherwise
	 * an attacker could swap a parent component with a symlink in
	 * the window between robust_unlink (which uses do_unlink_at,
	 * already secure) and the create here, and redirect the new
	 * file outside the module. */
	if ((ofd = do_open_at(dest, O_WRONLY | O_CREAT | O_TRUNC | O_EXCL, mode)) < 0) {
		int save_errno = errno;
		rsyserr(FERROR_XFER, save_errno, "open %s", full_fname(dest));
		errno = save_errno;
		return -1;
	}
	return ofd;
}

/* Copy contents of file @source to file @dest with mode @mode.
 *