#include <stdlib.h>

#include <skalibs/allreadwrite.h>
#include <skalibs/exec.h>
#include <skalibs/socket.h>
#include <skalibs/strerr.h>
#include <skalibs/types.h>

#define USAGE "sdnotifywrapper fd socket prog..."

int newsock(char const *p)
{
    int s = ipc_datagram_coe();
    if (s == -1)
        return -1;
    if (ipc_bind_reuse(s, p) == -1)
        return -1;
    return s;
}

int monitor(int nfd, int sfd)
{
    pid_t pid = doublefork();
    if (pid != 0)
        return pid > 0 ? 0 : -1;
    size_t len = 100, n;
    ssize_t r;
    char p[len];
    for (;;) {
        memset(&p, 0, sizeof p);
        r = ipc_recv(sfd, p, len-1, NULL);
        if (r == -1)
            strerr_diefu1sys(111, "ipc_recv") ;
        char *s = p;
        while (s) {
            char *t = strsep(&s, "\n");
            if (strcmp(t, "READY=1") == 0) {
                if (allwrite(nfd, "\n", 1) == -1)
                    strerr_diefu1sys(111, "write to nfd") ;
                exit(0);
            }
        }
    }
}

int main (int argc, char const *const *argv)
{
    int nfd, sfd;
    PROG = "sdnotifywrapper" ;

    if ((argc < 4) || !uint0_scan(argv[1], (unsigned int *)&nfd))
        strerr_dieusage(100, USAGE) ;
    sfd = newsock(argv[2]);
    if (sfd == -1)
        strerr_diefu1sys(111, "create sock") ;
    if (monitor(nfd, sfd) == -1)
        strerr_diefu1sys(111, "monitor") ;
    if (setenv("NOTIFY_SOCKET", argv[2], 1) == -1)
        strerr_diefu1sys(111, "setenv") ;
    xexec(argv+3) ;
}