[PATCH V1 23/32] char: save/restore chardev socket fds

[Steve Sistare <steven.sistare@oracle.com>]

From: Mark Kanda <mark.kanda@oracle.com>

Iterate through the character devices and save/restore the socket fds.

Signed-off-by: Mark Kanda <mark.kanda@oracle.com>
Signed-off-by: Steve Sistare <steven.sistare@oracle.com>
---
 chardev/char-socket.c   | 35 +++++++++++++++++++++++++++++++++++
 chardev/char.c          | 14 ++++++++++++++
 include/chardev/char.h  |  5 +++++
 include/sysemu/sysemu.h |  1 +
 migration/savevm.c      |  8 ++++++++
 5 files changed, 63 insertions(+)

diff --git a/chardev/char-socket.c b/chardev/char-socket.c
index ef62dbf..e08e7e1 100644
--- a/chardev/char-socket.c
+++ b/chardev/char-socket.c
@@ -36,6 +36,8 @@
 #include "qapi/qapi-visit-sockets.h"
 
 #include "chardev/char-io.h"
+#include "sysemu/sysemu.h"
+#include "qemu/cutils.h"
 
 /***********************************************************/
 /* TCP Net console */
@@ -400,6 +402,7 @@ static void tcp_chr_free_connection(Chardev *chr)
     SocketChardev *s = SOCKET_CHARDEV(chr);
     int i;
 
+    unsetenv_fd(chr->label);
     if (s->read_msgfds_num) {
         for (i = 0; i < s->read_msgfds_num; i++) {
             close(s->read_msgfds[i]);
@@ -1375,6 +1378,9 @@ static void qmp_chardev_open_socket(Chardev *chr,
             return;
         }
     }
+
+    load_char_socket_fd(chr);
+
 }
 
 static void qemu_chr_parse_socket(QemuOpts *opts, ChardevBackend *backend,
@@ -1517,3 +1523,32 @@ static void register_types(void)
 }
 
 type_init(register_types);
+
+void save_char_socket_fd(Chardev *chr)
+{
+    SocketChardev *sockchar = SOCKET_CHARDEV(chr);
+
+    if (sockchar->sioc) {
+        setenv_fd(chr->label, sockchar->sioc->fd);
+    }
+}
+
+void load_char_socket_fd(Chardev *chr)
+{
+    SocketChardev *sockchar;
+    QIOChannelSocket *sioc;
+
+    int fd = getenv_fd(chr->label);
+
+    if (fd != -1) {
+        unsetenv_fd(chr->label);
+        sockchar = SOCKET_CHARDEV(chr);
+        sioc = qio_channel_socket_accept(*sockchar->listener->sioc, fd, NULL);
+        if (sioc) {
+            tcp_chr_accept(sockchar->listener, sioc, chr);
+        } else {
+            error_printf("error: could not restore socket for %s\n",
+                         chr->label);
+        }
+    }
+}
diff --git a/chardev/char.c b/chardev/char.c
index 77e7ec8..8fd54cc 100644
--- a/chardev/char.c
+++ b/chardev/char.c
@@ -34,6 +34,7 @@
 #include "qapi/qapi-commands-char.h"
 #include "qapi/qmp/qerror.h"
 #include "sysemu/replay.h"
+#include "sysemu/sysemu.h"
 #include "qemu/help_option.h"
 #include "qemu/module.h"
 #include "qemu/option.h"
@@ -1174,3 +1175,16 @@ static void register_types(void)
 }
 
 type_init(register_types);
+
+static int chardev_is_socket(Object *child, void *opaque)
+{
+    if (CHARDEV_IS_SOCKET(child)) {
+        save_char_socket_fd((Chardev *) child);
+    }
+    return 0;
+}
+
+void save_chardev_fds(void)
+{
+    object_child_foreach(get_chardevs_root(), chardev_is_socket, NULL);
+}
diff --git a/include/chardev/char.h b/include/chardev/char.h
index 00589a6..80a9cf8 100644
--- a/include/chardev/char.h
+++ b/include/chardev/char.h
@@ -250,6 +250,8 @@ int qemu_chr_wait_connected(Chardev *chr, Error **errp);
     object_dynamic_cast(OBJECT(chr), TYPE_CHARDEV_RINGBUF)
 #define CHARDEV_IS_PTY(chr) \
     object_dynamic_cast(OBJECT(chr), TYPE_CHARDEV_PTY)
+#define CHARDEV_IS_SOCKET(chr) \
+    object_dynamic_cast(OBJECT(chr), TYPE_CHARDEV_SOCKET)
 
 typedef struct ChardevClass {
     ObjectClass parent_class;
@@ -290,4 +292,7 @@ GSource *qemu_chr_timeout_add_ms(Chardev *chr, guint ms,
 /* console.c */
 void qemu_chr_parse_vc(QemuOpts *opts, ChardevBackend *backend, Error **errp);
 
+void save_char_socket_fd(Chardev *);
+void load_char_socket_fd(Chardev *);
+
 #endif
diff --git a/include/sysemu/sysemu.h b/include/sysemu/sysemu.h
index 4dfc4ca..fa1a5c3 100644
--- a/include/sysemu/sysemu.h
+++ b/include/sysemu/sysemu.h
@@ -27,6 +27,7 @@ void qemu_remove_machine_init_done_notifier(Notifier *notify);
 
 void save_cpr_snapshot(const char *file, const char *mode, Error **errp);
 void load_cpr_snapshot(const char *file, Error **errp);
+void save_chardev_fds(void);
 
 extern int autostart;
 
diff --git a/migration/savevm.c b/migration/savevm.c
index 2902006..81f38c4 100644
--- a/migration/savevm.c
+++ b/migration/savevm.c
@@ -2700,6 +2700,12 @@ static QEMUFile *qf_file_open(const char *filename, int flags, int mode,
     return qemu_fopen_channel_input(ioc);
 }
 
+static int preserve_fd(const char *name, const char *val, void *handle)
+{
+    qemu_clr_cloexec(atoi(val));
+    return 0;
+}
+
 void save_cpr_snapshot(const char *file, const char *mode, Error **errp)
 {
     int ret = 0;
@@ -2761,6 +2767,8 @@ void save_cpr_snapshot(const char *file, const char *mode, Error **errp)
         if (qemu_preserve_ram(errp)) {
             return;
         }
+        save_chardev_fds();
+        walkenv(FD_PREFIX, preserve_fd, 0);
         qemu_system_exec_request();
         putenv((char *)"QEMU_START_FREEZE=");
     }
-- 
1.8.3.1