[PATCH 2/4] chardev: fix qemu_chr_open_fd() with fd_in==fd_out

From: marcandre.lureau@redhat.com
To: qemu-devel@nongnu.org
Cc: "Marc-André Lureau" <marcandre.lureau@redhat.com>,
	berrange@redhat.com, "Paolo Bonzini" <pbonzini@redhat.com>
Subject: [PATCH 2/4] chardev: fix qemu_chr_open_fd() with fd_in==fd_out
Date: Fri, 23 Jul 2021 14:28:23 +0400	[thread overview]
Message-ID: <20210723102825.1790112-3-marcandre.lureau@redhat.com> (raw)
In-Reply-To: <20210723102825.1790112-1-marcandre.lureau@redhat.com>

From: Marc-André Lureau <marcandre.lureau@redhat.com>

The "serial" chardev calls qemu_chr_open_fd() with the same fd. This
may lead to double-close as each QIOChannel owns the fd.

Instead, share the reference to the same QIOChannel.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
---
 chardev/char-fd.c | 15 +++++++++++++--
 1 file changed, 13 insertions(+), 2 deletions(-)

diff --git a/chardev/char-fd.c b/chardev/char-fd.c
index ee85a52c06..32166182bf 100644
--- a/chardev/char-fd.c
+++ b/chardev/char-fd.c
@@ -139,13 +139,24 @@ void qemu_chr_open_fd(Chardev *chr,
         qio_channel_set_name(QIO_CHANNEL(s->ioc_in), name);
         g_free(name);
     }
-    if (fd_out >= 0) {
+
+    if (fd_out < 0) {
+        return;
+    }
+
+    if (fd_out == fd_in) {
+        s->ioc_out = QIO_CHANNEL(object_ref(s->ioc_in));
+        name = g_strdup_printf("chardev-file-%s", chr->label);
+        qio_channel_set_name(QIO_CHANNEL(s->ioc_in), name);
+        g_free(name);
+    } else {
         s->ioc_out = QIO_CHANNEL(qio_channel_file_new_fd(fd_out));
         name = g_strdup_printf("chardev-file-out-%s", chr->label);
         qio_channel_set_name(QIO_CHANNEL(s->ioc_out), name);
         g_free(name);
-        qemu_set_nonblock(fd_out);
     }
+
+    qemu_set_nonblock(fd_out);
 }
 
 static void char_fd_class_init(ObjectClass *oc, void *data)
-- 
2.32.0.264.g75ae10bc75


