[Qemu-devel] [PATCH] qemu-char: Allow a chardev to reconnect if disconnected

[arei.gonglei]

From: Huangweidong <address@hidden>

Allow a socket chardev reconnect if the connection drops while in use.

Signed-off-by: Huangweidong <address@hidden>
Signed-off-by: Gonglei <address@hidden>
---
This patch is modified according to corey's patch. Some changes below:
1. IMO it's unnecessary that chardev reconnect if it fails to connect at 
startup.
Qemu exit in this scene. In this way the patch does not change interface of 
chardev.
It would be much more simple.
2. I set the reconnect timer one second, just like pty.

 include/sysemu/char.h |  2 ++
 qemu-char.c           | 50 ++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 52 insertions(+)

diff --git a/include/sysemu/char.h b/include/sysemu/char.h
index b81a6ff..f646ac8 100644
--- a/include/sysemu/char.h
+++ b/include/sysemu/char.h
@@ -19,6 +19,7 @@
 #define CHR_EVENT_MUX_OUT 4 /* mux-focus will move on */
 #define CHR_EVENT_CLOSED  5 /* connection closed */
 
+#define CHR_SOCK_RECONNECT_TIME 1 /* reconnection time (second) */
 
 #define CHR_IOCTL_SERIAL_SET_PARAMS   1
 typedef struct {
@@ -82,6 +83,7 @@ struct CharDriverState {
     guint fd_in_tag;
     QemuOpts *opts;
     QTAILQ_ENTRY(CharDriverState) next;
+    QEMUTimer *recon_timer;
 };
 
 /**
diff --git a/qemu-char.c b/qemu-char.c
index 54ed244..a87a345 100644
--- a/qemu-char.c
+++ b/qemu-char.c
@@ -96,9 +96,17 @@ void qemu_chr_be_event(CharDriverState *s, int event)
     /* Keep track if the char device is open */
     switch (event) {
         case CHR_EVENT_OPENED:
+            if (s->recon_timer) {
+                timer_del(s->recon_timer);
+            }
             s->be_open = 1;
             break;
         case CHR_EVENT_CLOSED:
+            if (s->recon_timer) {
+                timer_mod(s->recon_timer,
+                (get_clock() +
+                 (CHR_SOCK_RECONNECT_TIME * get_ticks_per_sec())));
+            }
             s->be_open = 0;
             break;
     }
@@ -2619,6 +2627,43 @@ static void tcp_chr_close(CharDriverState *chr)
     qemu_chr_be_event(chr, CHR_EVENT_CLOSED);
 }
 
+static void recon_timeout(void *opaque)
+{
+    CharDriverState *chr = opaque;
+    QemuOpts *opts = chr->opts;
+    TCPCharDriver *tcp = (TCPCharDriver *)chr->opaque;
+    int fd = -1;
+    Error *local_err = NULL;
+
+    if (chr->be_open) {
+        return;
+    }
+
+    if (tcp->is_unix) {
+        fd = unix_connect_opts(opts, &local_err, NULL, NULL);
+    } else {
+        fd = inet_connect_opts(opts, &local_err, NULL, NULL);
+    }
+
+    if (fd < 0) {
+        goto fail;
+    }
+
+    tcp->fd = fd;
+    socket_set_nodelay(fd);
+    tcp->chan = io_channel_from_socket(tcp->fd);
+    tcp_chr_connect(chr);
+    printf("chardev: socket reconnect sucess\n");
+    return;
+
+fail:
+    if (local_err) {
+        qerror_report_err(local_err);
+        error_free(local_err);
+    }
+    qemu_chr_be_event(chr, CHR_EVENT_CLOSED);
+}
+
 static CharDriverState *qemu_chr_open_socket_fd(int fd, bool do_nodelay,
                                                 bool is_listen, bool is_telnet,
                                                 bool is_waitconnect,
@@ -2693,6 +2738,11 @@ static CharDriverState *qemu_chr_open_socket_fd(int fd, 
bool do_nodelay,
         socket_set_nodelay(fd);
         s->chan = io_channel_from_socket(s->fd);
         tcp_chr_connect(chr);
+        chr->recon_timer = timer_new(QEMU_CLOCK_REALTIME, SCALE_NS,
+                                 recon_timeout, chr);
+        timer_mod(chr->recon_timer,
+                   (get_clock() +
+                    (CHR_SOCK_RECONNECT_TIME * get_ticks_per_sec())));
     }
 
     if (is_listen && is_waitconnect) {
-- 
1.7.12.4