ipc: start supporting sending/receiving more than 3 FDs

[public-inbox.git] / lib / PublicInbox / Spawn.pm

diff --git a/lib/PublicInbox/Spawn.pm b/lib/PublicInbox/Spawn.pm
index 7d0d95977c813c503a0f5fe20ed9f46b819eac21..b35bf54c111265cc26e24fc1cd6c7d381816822b 100644 (file)
--- a/lib/PublicInbox/Spawn.pm
+++ b/lib/PublicInbox/Spawn.pm
@@ -209,20 +209,22 @@ my $fdpass = <<'FDPASS';
 #include <sys/socket.h>
 
 #if defined(CMSG_SPACE) && defined(CMSG_LEN)
-struct my_3fds { int fds[3]; };
+#define SEND_FD_CAPA 3
+#define SEND_FD_SPACE (SEND_FD_CAPA * sizeof(int))
 union my_cmsg {
        struct cmsghdr hdr;
-       char pad[sizeof(struct cmsghdr)+ 8 + sizeof(struct my_3fds) + 8];
+       char pad[sizeof(struct cmsghdr) + 16 + SEND_FD_SPACE];
 };
 
-int send_cmd4(PerlIO *s, int in, int out, int err, SV *data, int flags)
+int send_cmd4(PerlIO *s, SV *svfds, SV *data, int flags)
 {
        struct msghdr msg = { 0 };
-       struct iovec iov;
        union my_cmsg cmsg = { 0 };
-       int *fdp;
-       size_t i;
        STRLEN dlen = 0;
+       struct iovec iov;
+       AV *fds = (AV *)SvRV(svfds);
+       I32 i, nfds = av_len(fds) + 1;
+       int *fdp;
 
        if (SvOK(data)) {
                iov.iov_base = SvPV(data, dlen);
@@ -234,16 +236,22 @@ int send_cmd4(PerlIO *s, int in, int out, int err, SV *data, int flags)
        }
        msg.msg_iov = &iov;
        msg.msg_iovlen = 1;
-       msg.msg_control = &cmsg.hdr;
-       msg.msg_controllen = CMSG_SPACE(sizeof(struct my_3fds));
-
-       cmsg.hdr.cmsg_level = SOL_SOCKET;
-       cmsg.hdr.cmsg_type = SCM_RIGHTS;
-       cmsg.hdr.cmsg_len = CMSG_LEN(sizeof(struct my_3fds));
-       fdp = (int *)CMSG_DATA(&cmsg.hdr);
-       *fdp++ = in;
-       *fdp++ = out;
-       *fdp++ = err;
+       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);
+               }
+       }
        return sendmsg(PerlIO_fileno(s), &msg, flags) >= 0;
 }
 
@@ -263,17 +271,17 @@ void recv_cmd4(PerlIO *s, SV *buf, STRLEN n)
        msg.msg_iov = &iov;
        msg.msg_iovlen = 1;
        msg.msg_control = &cmsg.hdr;
-       msg.msg_controllen = CMSG_SPACE(sizeof(struct my_3fds));
+       msg.msg_controllen = CMSG_SPACE(SEND_FD_SPACE);
 
        i = recvmsg(PerlIO_fileno(s), &msg, 0);
        if (i < 0)
                croak("recvmsg: %s", strerror(errno));
        SvCUR_set(buf, i);
        if (i > 0 && cmsg.hdr.cmsg_level == SOL_SOCKET &&
-                       cmsg.hdr.cmsg_type == SCM_RIGHTS &&
-                       cmsg.hdr.cmsg_len == CMSG_LEN(sizeof(struct my_3fds))) {
+                       cmsg.hdr.cmsg_type == SCM_RIGHTS) {
+               size_t len = cmsg.hdr.cmsg_len;
                int *fdp = (int *)CMSG_DATA(&cmsg.hdr);
-               for (i = 0; i < 3; i++)
+               for (i = 0; CMSG_LEN((i + 1) * sizeof(int)) <= len; i++)
                        Inline_Stack_Push(sv_2mortal(newSViv(*fdp++)));
        }
        Inline_Stack_Done;