avoid crashes on log client teardown

[disorder] / server / server.c

diff --git a/server/server.c b/server/server.c
index 5a11b8c..1e4c6ca 100644 (file)
--- a/server/server.c
+++ b/server/server.c
@@ -115,10 +115,12 @@ static int writer_error(ev_source attribute((unused)) *ev,
     /* writer is done */
     c->w = 0;
     if(c->r == 0) {
-      D(("server writer_error closes %d", fd));
+      //D(("server writer_error closes %d", fd));
+      info("server writer_error closes %d because all done", fd); /* TODO */
       xclose(fd);              /* reader is done too, close */
     } else {
-      D(("server writer_error shutdown %d SHUT_WR", fd));
+      //D(("server writer_error shutdown %d SHUT_WR", fd));
+      info("server writer_error shutdown %d SHUT_WR", fd); /* TODO */
       xshutdown(fd, SHUT_WR);  /* reader is not done yet */
     }
   } else {
@@ -126,6 +128,7 @@ static int writer_error(ev_source attribute((unused)) *ev,
       error(errno_value, "S%x write error on socket", c->tag);
     if(c->r)
       ev_reader_cancel(c->r);
+    info("server writer_error closes %d because errno=%d", fd, errno_value); /* TODO */
     xclose(fd);
   }
   return 0;
@@ -139,9 +142,12 @@ static int reader_error(ev_source attribute((unused)) *ev,
 
   D(("server reader_error %d %d", fd, errno_value));
   error(errno, "S%x read error on socket", c->tag);
-  ev_writer_cancel(c->w);
+  if(c->w) {
+    ev_writer_cancel(c->w);
+    c->w = 0;
+  }
   ev_report(ev);
-  info("closing fd %d", fd);
+  info("reader_error closing fd %d", fd); /* TODO */
   xclose(fd);
   return 0;
 }
@@ -665,21 +671,19 @@ static int c_random_enabled(struct conn *c,
   return 1;                    /* completed */
 }
 
+static void got_stats(char *stats, void *u) {
+  struct conn *const c = u;
+
+  sink_printf(ev_writer_sink(c->w), "253 stats\n%s\n.\n", stats);
+  /* Now we can start processing commands again */
+  ev_reader_enable(c->r);
+}
+
 static int c_stats(struct conn *c,
                   char attribute((unused)) **vec,
                   int attribute((unused)) nvec) {
-  char **v;
-  int nv, n;
-
-  v = trackdb_stats(&nv);
-  sink_printf(ev_writer_sink(c->w), "253 stats\n");
-  for(n = 0; n < nv; ++n) {
-    if(v[n][0] == '.')
-      sink_writes(ev_writer_sink(c->w), ".");
-    sink_printf(ev_writer_sink(c->w), "%s\n", v[n]);
-  }
-  sink_writes(ev_writer_sink(c->w), ".\n");
-  return 1;
+  trackdb_stats_subprocess(c->ev, got_stats, c);
+  return 0;                            /* not yet complete */
 }
 
 static int c_volume(struct conn *c,
@@ -731,8 +735,11 @@ static int logging_reader_callback(ev_source *ev,
 
   /* don't log to this conn any more */
   eventlog_remove(c->lo);
-  /* terminate the log output */
-  sink_writes(ev_writer_sink(c->w), ".\n");
+  if(c->w) {
+    /* Terminate the log output, but only if the writer hasn't been killed off
+     * from a failure on some earlier write */
+    sink_writes(ev_writer_sink(c->w), ".\n");
+  }
   /* restore the reader callback */
   c->reader = reader_callback;
   /* ...and exit via it */
@@ -742,6 +749,11 @@ static int logging_reader_callback(ev_source *ev,
 static void logclient(const char *msg, void *user) {
   struct conn *c = user;
 
+  if(!c->w || !c->r) {
+    /* This connection has gone up in smoke for some reason */
+    eventlog_remove(c->lo);
+    return;
+  }
   sink_printf(ev_writer_sink(c->w), "%"PRIxMAX" %s\n",
              (uintmax_t)time(0), msg);
 }