From 5dc2fdac15fd470e9bdf915628061312fdb689e5 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Gustav=20H=C3=A5llberg?= <gustav@gmail.com>
Date: Sat, 17 Jan 2009 00:50:23 +0100
Subject: properly handle when tty writes block; fixes possible lock-up
 introduced by 277a06dbb45f4f249bb3f09d524ae064c842b7c5


diff --git a/tty.c b/tty.c
index b0883b9..5e4ff7a 100644
--- a/tty.c
+++ b/tty.c
@@ -959,9 +959,28 @@ void tty_flush __P ((void))
     char *data = tty_write_state.data;
     while (n > 0) {
         ssize_t r;
-        do {
+        for (;;) {
             r = write(tty_write_state.fd, data, n);
-        } while (r < 0 && (errno == EAGAIN || errno == EINTR));
+            if (r >= 0)
+                break;
+            if (errno == EINTR)
+                continue;
+            if (errno != EAGAIN) {
+                fprintf(stderr, "Cannot write to tty: %s\n", strerror(errno));
+                abort();
+            }
+            fd_set wfds;
+            FD_ZERO(&wfds);
+            FD_SET(tty_write_state.fd, &wfds);
+            do {
+                r = select(tty_write_state.fd + 1, NULL, &wfds, NULL, NULL);
+            } while (r < 0 && errno == EINTR);
+            if (r <= 0) {
+                fprintf(stderr, "Cannot write to tty; select failed: %s\n",
+                        r == 0 ? "returned zero" : strerror(errno));
+                abort();
+            }
+        }
         if (r < 0) {
             fprintf(stderr, "Cannot write to tty: %s\n", strerror(errno));
             abort();
-- 
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