diff options
| -rw-r--r-- | tools/hi-q.c | 39 |
1 files changed, 31 insertions, 8 deletions
diff --git a/tools/hi-q.c b/tools/hi-q.c index 1e71ef4..3de9f1c 100644 --- a/tools/hi-q.c +++ b/tools/hi-q.c @@ -209,6 +209,11 @@ int main(int argc, char** argv, char const * const * env) { vector<pid_t> kidpid(nkids); // indexed by kid number + const int rEnd(0); // end of a pipe for reading + const int wEnd(1); // end of a pipe for writing + int sync[2]; + if (pipe(sync) != 0) cerr << "sync pipe failed" << endl; + // At this point, there are some loop invariants; // (a) fd0 is open (standard input) and has the email msg, // ready for the next child to read, and @@ -247,10 +252,11 @@ int main(int argc, char** argv, char const * const * env) { // It will be written by this kid and read by the next kid. // For the last kid, the loose end connects to hi-q. // It will be written by hi-q and read by the last kid. + int lastkid = (ii == nkids-1); #define flip(a,b) (lastkid ? b : a) - loose_end = datapipe[flip(0,1)]; - kid_end = datapipe[flip(1,0)]; + loose_end = datapipe[flip(rEnd, wEnd)]; + kid_end = datapipe[flip(wEnd, rEnd)]; kidpid[ii] = fork(); if (!kidpid[ii]) { /*** child code ***/ @@ -262,9 +268,17 @@ int main(int argc, char** argv, char const * const * env) { cerr << "setpgid failed! " << errno << " ... "; perror(0); } - cerr << "kid [" << ii << "] starts: " << getpid() + if (ii == 0) { + int junk(1); + write(sync[wEnd], &junk, 1); + //cerr << "sync sent" << endl; + } + +#if 1 + cerr << "kid [" << ii << "] " << getpid() << " kidpid[0] " << kidpid[0] - << endl; + << " starts" << endl; +#endif // Now that we are through creating pipes, we don't // need to continue blocking fd1: close(1); @@ -308,15 +322,24 @@ int main(int argc, char** argv, char const * const * env) { // otherwise it won't fully exist when the other kids start, // and depending race conditions, the setpgid could fail ////////??? if (1) usleep(0); - if (ii == 0) usleep(1); -#if 1 - cerr << "forked kid #" << ii +///////??? if (ii == 0) usleep(1); + + if (ii==0) { + int junk; + //cerr << "about to read sync" << endl; + ssize_t rslt = read(sync[rEnd], &junk, 1); + //cerr << "back from read sync: " << rslt << endl; + if (rslt) {} + } + +#if 0 + cerr << "apparent kid #" << ii << " (" << kidpid[ii] << ") " << endl; #endif } /* end loop starting all kids */ -// here with the whole pipeline of kids running +// here with the whole pipeline of kids launched close(0); // the reading end of stdin was // delegated to the first child |