From 25e136abd74f4b8d5eb5a69ec641eb5d757c91ce Mon Sep 17 00:00:00 2001
From: John Denker <jsd@av8n.com>
Date: Sun, 15 Jul 2012 03:14:56 -0700
Subject: working, cleaner now

---
 tools/hi-q.c    | 66 ++++++++++++++++++++++++++++-----------------------------
 tools/hi-test.c |  2 +-
 2 files changed, 34 insertions(+), 34 deletions(-)

(limited to 'tools')

diff --git a/tools/hi-q.c b/tools/hi-q.c
index f2da44d..6d73b9b 100644
--- a/tools/hi-q.c
+++ b/tools/hi-q.c
@@ -217,7 +217,7 @@ int main(int argc, char** argv, char const * const * env) {
   if (pipe(resync) != 0) cerr << "resync pipe failed" << endl;
 
 // At this point, there are some loop invariants;
-// (a) fd0 is open (standard input) and has the email msg, 
+// (a) fd0 is open (standard input) and has the email msg,
 //     ready for the next child to read, and
 // (b) fd1 is open (nonstandard input) and has envelope information.
 //     We need it to be open, so that pipe()
@@ -267,35 +267,40 @@ int main(int argc, char** argv, char const * const * env) {
                             // equal to pid of kid#0
       if (ii) kidgroup = kidpid[0];
       if (setpgid(0, kidgroup) != 0) {
-        cerr << "*** kid " << ii 
+        cerr << "*** kid " << ii
            << " setpgid failed! " << errno << " ... ";
         perror(0);
       } else {
-        cerr << "*** kid " << ii << " setpgid OK" << endl;
+        // cerr << "*** kid " << ii << " setpgid OK" << endl;
       }
 
-// everybody else has to wait for us to get this far
+// ... everybody else has to wait for us to get this far ...
+// ... so that the new process group will be valid ...
+// Write-a-byte synchronization is released when the *first* guy writes.
       if (ii == 0) {
         int junk(1);
         write(sync[wEnd], &junk, 1);
-        cerr << "sync sent" << endl;
+        //cerr << "sync sent" << endl;
       }
-#if 1
-      cerr << "kid [" << ii << "] " << getpid() 
+#if 0
+      cerr << "kid [" << ii << "] " << getpid()
         << "  kidpid[0]: " << kidpid[0]
         << "  pgid: " << getpgid(0)
         << " starts" << endl;
 #endif
+
       close(resync[wEnd]);
-// Now we wait for everybody else:
+// ... now we must wait for everybody else, because ...
+// ... if we do the exec(), the new process group becomes invalid ...
+// Close synchronization is released when the *last* guy closes.
       if (ii==0) {
         int junk;
-        cerr << "about to read resync" << endl;
+        //cerr << "about to read resync" << endl;
         ssize_t rslt = read(resync[rEnd], &junk, 1);
-        if (rslt != 1) {
-          cerr << "bad sync ... 1 != " << rslt << endl;
+        if (rslt < 0 ) {
+          cerr << "bad sync ... " << rslt << endl;
         } else {
-          cerr << "back from read resync, good: " << rslt << endl;
+          // cerr << "back from read resync, good: " << rslt << endl;
         }
       }
 
@@ -318,7 +323,7 @@ int main(int argc, char** argv, char const * const * env) {
       }
 
       close(kid_end);           // use fd1 instead now
-      // OK, at this point this kid is set up to read fd0 and write fd1 
+      // OK, at this point this kid is set up to read fd0 and write fd1
       // (except last kid reads fd1 as well as fd0).
 ////  probe_fd();
 
@@ -343,25 +348,19 @@ int main(int argc, char** argv, char const * const * env) {
     close(kid_end);
 
 // Let kid #0 run a little ways:
-      if (ii==0) {
-        int junk;
-        cerr << "about to read sync" << endl;
-        ssize_t rslt = read(sync[rEnd], &junk, 1);
-        if (rslt < 0) {
-          cerr << "bad sync ... 1 != " << rslt << endl;
-        } else {
-          cerr << "back from read sync, good: " << rslt << endl;
-        }
+    if (ii==0) {
+      int junk;
+      //cerr << "about to read sync" << endl;
+      ssize_t rslt = read(sync[rEnd], &junk, 1);
+      if (rslt != 1) {
+        cerr << "bad sync ... 1 != " << rslt << endl;
+      } else {
+        //cerr << "back from read sync, good: " << rslt << endl;
       }
-
-// it is important to let kid#0 run a while;
-// 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 0
-    cerr << "apparent kid #" << ii 
+    cerr << "apparent kid #" << ii
             << " (" << kidpid[ii] << ") "
             << endl;
 #endif
@@ -369,7 +368,8 @@ int main(int argc, char** argv, char const * const * env) {
 
 // here with the whole pipeline of kids launched
 
-      close(resync[wEnd]);
+  close(resync[wEnd]);
+  close(resync[rEnd]);
 
   close(0);             // the reading end of stdin was
                         // delegated to the first child
@@ -384,13 +384,13 @@ int main(int argc, char** argv, char const * const * env) {
     if (WIFEXITED(kidstatus)) {
       int sts = WEXITSTATUS(kidstatus);
       if (sts == 1) {
-        cerr << "hi-q says: kid " << ii 
+        cerr << "hi-q says: kid " << ii
              << " i.e. '" << filter[ii][0] << "' reports spam."
              << endl;
         panic(ex_spam);
       }
       if (sts != 0) {
-        cerr << "hi-q says: kid " << ii 
+        cerr << "hi-q says: kid " << ii
              << " i.e. '" << filter[ii][0] << "'"
              << " suffered an error: " << sts
              << endl;
@@ -433,6 +433,6 @@ fprintf(stderr, "About to wait for kid #%d (%d)\n",
   sleep(1);
 #endif
 // the last kid did not exit but was killed:
-  return ex_syserr;             
+  return ex_syserr;
 
 }
diff --git a/tools/hi-test.c b/tools/hi-test.c
index 01e475b..3086535 100644
--- a/tools/hi-test.c
+++ b/tools/hi-test.c
@@ -3,5 +3,5 @@
 
 using namespace std;
 int main(){
-  cerr << "++++   " << getpid() << " : " << getpgid(0) << endl;
+  cerr << "++++ hi-test pid: " << getpid() << "  group: " << getpgid(0) << endl;
 }
-- 
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