stdout and stderr should be made O_NONBLOCK so that we don't end up blocking

the entire process because stdout is busy.

Arguably, this shouldn't apply to stderr when we're printing our own error
messages to it, but I'll leave that fix for another time.

[originally from svn r7738]

diff --git a/unix/uxplink.c b/unix/uxplink.c
index 6b56d2af1fc5d61db6b7102006a91265b8921639..c1117e4391cc38c24f0c920744e1e66a5c417b5d 100644 (file)
--- a/unix/uxplink.c
+++ b/unix/uxplink.c
@@ -385,7 +385,7 @@ void try_output(int is_stderr)
     ret = write(fd, senddata, sendlen);
     if (ret > 0)
        bufchain_consume(chain, ret);
-    else if (ret < 0) {
+    else if (ret < 0 && errno != EWOULDBLOCK) {
        perror(is_stderr ? "stderr: write" : "stdout: write");
        exit(1);
     }
@@ -883,6 +883,23 @@ int main(int argc, char **argv)
     local_tty = (tcgetattr(0, &orig_termios) == 0);
     atexit(cleanup_termios);
     ldisc_update(NULL, 1, 1);
+
+    {
+       int fl;
+       /*
+        * Make sure that stdout/err are non-blocking.
+        */
+       if ((fl = fcntl(1, F_GETFL)) == -1 ||
+           fcntl(1, F_SETFL, fl | O_NONBLOCK) == -1) {
+           perror("stdout");
+           exit(1);
+       }
+       if ((fl = fcntl(2, F_GETFL)) == -1 ||
+           fcntl(2, F_SETFL, fl | O_NONBLOCK) == -1) {
+           perror("stderr");
+           exit(1);
+       }
+    }
     sending = FALSE;
     now = GETTICKCOUNT();