- FLOCK(f);
-
- /* If the child's end of the pipe happens to already be on the final
- * fd number to which it will be assigned (either 0 or 1), it must
- * be moved to a different fd. Otherwise, there is no safe way to
- * remove the close-on-exec flag in the child without also creating
- * a file descriptor leak race condition in the parent. */
- if (p[1-op] == 1-op) {
- int tmp = fcntl(F_DUPFD_CLOEXEC, 1-op, 0);
- if (tmp < 0) {
- e = errno;
- goto fail;
- }
- __syscall(SYS_close, p[1-op]);
- p[1-op] = tmp;
- }