+#if defined(CMSG_SPACE) && defined(CMSG_LEN)
+#define SEND_FD_CAPA 10
+#define SEND_FD_SPACE (SEND_FD_CAPA * sizeof(int))
+union my_cmsg {
+ struct cmsghdr hdr;
+ char pad[sizeof(struct cmsghdr) + 16 + SEND_FD_SPACE];
+};
+
+SV *send_cmd4(PerlIO *s, SV *svfds, SV *data, int flags)
+{
+ struct msghdr msg = { 0 };
+ union my_cmsg cmsg = { 0 };
+ STRLEN dlen = 0;
+ struct iovec iov;
+ ssize_t sent;
+ AV *fds = (AV *)SvRV(svfds);
+ I32 i, nfds = av_len(fds) + 1;
+ int *fdp;
+ unsigned tries = 0;
+
+ if (SvOK(data)) {
+ iov.iov_base = SvPV(data, dlen);
+ iov.iov_len = dlen;
+ }
+ if (!dlen) { /* must be non-zero */
+ iov.iov_base = &msg.msg_namelen; /* whatever */
+ iov.iov_len = 1;
+ }
+ msg.msg_iov = &iov;
+ msg.msg_iovlen = 1;
+ if (nfds) {
+ if (nfds > SEND_FD_CAPA) {
+ fprintf(stderr, "FIXME: bump SEND_FD_CAPA=%d\n", nfds);
+ nfds = SEND_FD_CAPA;
+ }
+ msg.msg_control = &cmsg.hdr;
+ msg.msg_controllen = CMSG_SPACE(nfds * sizeof(int));
+ cmsg.hdr.cmsg_level = SOL_SOCKET;
+ cmsg.hdr.cmsg_type = SCM_RIGHTS;
+ cmsg.hdr.cmsg_len = CMSG_LEN(nfds * sizeof(int));
+ fdp = (int *)CMSG_DATA(&cmsg.hdr);
+ for (i = 0; i < nfds; i++) {
+ SV **fd = av_fetch(fds, i, 0);
+ *fdp++ = SvIV(*fd);
+ }
+ }
+ do {
+ sent = sendmsg(PerlIO_fileno(s), &msg, flags);
+ } while (sent < 0 && sleep_wait(&tries, errno));
+ return sent >= 0 ? newSViv(sent) : &PL_sv_undef;
+}
+
+void recv_cmd4(PerlIO *s, SV *buf, STRLEN n)
+{
+ union my_cmsg cmsg = { 0 };
+ struct msghdr msg = { 0 };
+ struct iovec iov;
+ ssize_t i;
+ Inline_Stack_Vars;
+ Inline_Stack_Reset;
+
+ if (!SvOK(buf))
+ sv_setpvn(buf, "", 0);
+ iov.iov_base = SvGROW(buf, n + 1);
+ iov.iov_len = n;
+ msg.msg_iov = &iov;
+ msg.msg_iovlen = 1;
+ msg.msg_control = &cmsg.hdr;
+ msg.msg_controllen = CMSG_SPACE(SEND_FD_SPACE);
+
+ i = recvmsg(PerlIO_fileno(s), &msg, 0);
+ if (i < 0)
+ Inline_Stack_Push(&PL_sv_undef);
+ else
+ SvCUR_set(buf, i);
+ if (i > 0 && cmsg.hdr.cmsg_level == SOL_SOCKET &&
+ cmsg.hdr.cmsg_type == SCM_RIGHTS) {
+ size_t len = cmsg.hdr.cmsg_len;
+ int *fdp = (int *)CMSG_DATA(&cmsg.hdr);
+ for (i = 0; CMSG_LEN((i + 1) * sizeof(int)) <= len; i++)
+ Inline_Stack_Push(sv_2mortal(newSViv(*fdp++)));
+ }
+ Inline_Stack_Done;