#include <poll.h>
#include <stdio.h>
#include <signal.h>
#include <stdlib.h>
#include <strings.h>
#include <sys/socket.h>

extern const char *__progname;

#include "nf.h"
#include "scm-rights.h"

#include "forker.h"

void forker_main(int cfd, int dfd)
{
 void (*fn)(int, int);
 unsigned char msg[sizeof(void (*)(int, int))];
 unsigned char ctlbuf[CMSPACE(2*sizeof(int))];
 struct msghdr mh;
 struct cmsghdr cmh;
 struct iovec iov;
 int fds[2];
 int rv;
 struct pollfd pfd[2];
 pid_t kid;

 signal(SIGCHLD,SIG_IGN);
 setproctitle("forker");
 while (1)
  { pfd[0].fd = cfd;
    pfd[0].events = POLLIN | POLLRDNORM;
    pfd[1].fd = dfd;
    pfd[1].events = POLLIN | POLLRDNORM;
    rv = poll(&pfd[0],2,INFTIM);
    if (rv < 0) exit(0);
    if (pfd[1].revents & (POLLIN|POLLRDNORM|POLLHUP))
     { fprintf(stderr,"%s: forker: parent death pipe readable\n",__progname);
       exit(0);
     }
    if (pfd[0].revents & POLLHUP)
     { fprintf(stderr,"%s: forker control pipe hangup\n",__progname);
       exit(0);
     }
    if (! (pfd[0].revents & (POLLIN|POLLRDNORM)))
     { fprintf(stderr,"%s: forker weird poll\n",__progname);
       exit(0);
     }
    iov.iov_base = &msg[0];
    iov.iov_len = sizeof(msg);
    mh.msg_name = 0;
    mh.msg_namelen = 0;
    mh.msg_iov = &iov;
    mh.msg_iovlen = 1;
    mh.msg_control = &ctlbuf[0];
    mh.msg_controllen = sizeof(ctlbuf);
    mh.msg_flags = 0;
    rv = recvmsg(cfd,&mh,0);
    if (rv < 0)
     { fprintf(stderr,"%s: forker recvmsg: %s\n",__progname,strerror(errno));
       exit(1);
     }
    if (rv != sizeof(void (*)(int, int)))
     { fprintf(stderr,"%s: forker msg size (%d) wrong (not %d)\n",__progname,rv,(int)sizeof(void (*)(int, int)));
       exit(1);
     }
    if (mh.msg_controllen < sizeof(struct cmsghdr))
     { fprintf(stderr,"%s: forker msg controllen (%d) too small (< %d)\n",__progname,(int)mh.msg_controllen,(int)sizeof(struct cmsghdr));
       exit(1);
     }
    bcopy(&ctlbuf[0],&cmh,sizeof(struct cmsghdr));
    if (cmh.cmsg_level != SOL_SOCKET)
     { fprintf(stderr,"%s: forker msg level (%d) wrong (not %d)\n",__progname,(int)cmh.cmsg_level,(int)SOL_SOCKET);
       exit(1);
     }
    if (cmh.cmsg_type != SCM_RIGHTS)
     { fprintf(stderr,"%s: forker msg type (%d) wrong (not %d)\n",__progname,(int)cmh.cmsg_type,(int)SCM_RIGHTS);
       exit(1);
     }
    if (cmh.cmsg_len < CMLEN(2*sizeof(int)))
     { fprintf(stderr,"%s: forker cmsg len (%d) too small (< %d)\n",__progname,(int)cmh.cmsg_len,(int)CMLEN(2*sizeof(int)));
       exit(1);
     }
    bcopy(&ctlbuf[CMSKIP(&cmh)],&fds[0],2*sizeof(int));
    kid = nf_fork();
    if (! kid) break;
    close(fds[0]);
    close(fds[1]);
  }
 close(cfd);
 close(dfd);
 bcopy(&msg[0],&fn,sizeof(void (*)(int, int)));
 (*fn)(fds[0],fds[1]);
 _exit(0);
}