[PATCH V9 39/46] chardev: cpr for sockets

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

Save accepted socket fds before cpr-exec, and look for them after.
Block cpr-exec if a socket enables the TLS or websocket option.
Allow a monitor socket by closing it on exec.

Signed-off-by: Mark Kanda <mark.kanda@oracle.com>
Signed-off-by: Steve Sistare <steven.sistare@oracle.com>
---
 chardev/char-socket.c         | 48 +++++++++++++++++++++++++++++++++++++++++++
 include/chardev/char-socket.h |  1 +
 monitor/hmp.c                 |  3 +++
 monitor/qmp.c                 |  4 ++++
 4 files changed, 56 insertions(+)

diff --git a/chardev/char-socket.c b/chardev/char-socket.c
index dc4e218..f93bae8 100644
--- a/chardev/char-socket.c
+++ b/chardev/char-socket.c
@@ -26,6 +26,8 @@
 #include "chardev/char.h"
 #include "io/channel-socket.h"
 #include "io/channel-websock.h"
+#include "migration/blocker.h"
+#include "migration/cpr-state.h"
 #include "qemu/error-report.h"
 #include "qemu/module.h"
 #include "qemu/option.h"
@@ -33,6 +35,7 @@
 #include "qapi/clone-visitor.h"
 #include "qapi/qapi-visit-sockets.h"
 #include "qemu/yank.h"
+#include "sysemu/sysemu.h"
 
 #include "chardev/char-io.h"
 #include "chardev/char-socket.h"
@@ -358,6 +361,11 @@ static void tcp_chr_free_connection(Chardev *chr)
     SocketChardev *s = SOCKET_CHARDEV(chr);
     int i;
 
+    if (chr->cpr_enabled) {
+        cpr_delete_fd(chr->label, 0);
+    }
+    migrate_del_blocker(&s->cpr_blocker);
+
     if (s->read_msgfds_num) {
         for (i = 0; i < s->read_msgfds_num; i++) {
             close(s->read_msgfds[i]);
@@ -923,6 +931,10 @@ static void tcp_chr_accept(QIONetListener *listener,
                                QIO_CHANNEL(cioc));
     }
     tcp_chr_new_client(chr, cioc);
+
+    if (s->sioc && chr->cpr_enabled) {
+        cpr_resave_fd(chr->label, 0, s->sioc->fd);
+    }
 }
 
 
@@ -1178,6 +1190,27 @@ static gboolean socket_reconnect_timeout(gpointer opaque)
     return false;
 }
 
+static int load_char_socket_fd(Chardev *chr, Error **errp)
+{
+    ERRP_GUARD();
+    SocketChardev *sockchar = SOCKET_CHARDEV(chr);
+    QIOChannelSocket *sioc;
+    const char *label = chr->label;
+    int fd = cpr_find_fd(label, 0);
+
+    if (fd != -1) {
+        sockchar = SOCKET_CHARDEV(chr);
+        sioc = qio_channel_socket_new_fd(fd, errp);
+        if (sioc) {
+            tcp_chr_accept(sockchar->listener, sioc, chr);
+            object_unref(OBJECT(sioc));
+        } else {
+            error_prepend(errp, "could not restore socket for %s", label);
+            return -1;
+        }
+    }
+    return 0;
+}
 
 static int qmp_chardev_open_socket_server(Chardev *chr,
                                           bool is_telnet,
@@ -1388,6 +1421,19 @@ static void qmp_chardev_open_socket(Chardev *chr,
     }
     s->registered_yank = true;
 
+    if (!s->tls_creds && !s->is_websock) {
+        qemu_chr_set_feature(chr, QEMU_CHAR_FEATURE_CPR);
+    } else if (!chr->reopen_on_cpr) {
+        s->cpr_blocker = NULL;
+        error_setg(&s->cpr_blocker,
+                   "error: socket %s is not cpr capable due to %s option",
+                   chr->label, (s->tls_creds ? "TLS" : "websocket"));
+        if (migrate_add_blockers(&s->cpr_blocker, errp, MIG_MODE_CPR_EXEC,
+                                 -1)) {
+            return;
+        }
+    }
+
     /* be isn't opened until we get a connection */
     *be_opened = false;
 
@@ -1403,6 +1449,8 @@ static void qmp_chardev_open_socket(Chardev *chr,
             return;
         }
     }
+
+    load_char_socket_fd(chr, errp);
 }
 
 static void qemu_chr_parse_socket(QemuOpts *opts, ChardevBackend *backend,
diff --git a/include/chardev/char-socket.h b/include/chardev/char-socket.h
index 0708ca6..1c3abf7 100644
--- a/include/chardev/char-socket.h
+++ b/include/chardev/char-socket.h
@@ -78,6 +78,7 @@ struct SocketChardev {
     bool connect_err_reported;
 
     QIOTask *connect_task;
+    Error *cpr_blocker;
 };
 typedef struct SocketChardev SocketChardev;
 
diff --git a/monitor/hmp.c b/monitor/hmp.c
index 15ca047..75e6739 100644
--- a/monitor/hmp.c
+++ b/monitor/hmp.c
@@ -1501,4 +1501,7 @@ void monitor_init_hmp(Chardev *chr, bool use_readline, Error **errp)
     qemu_chr_fe_set_handlers(&mon->common.chr, monitor_can_read, monitor_read,
                              monitor_event, NULL, &mon->common, NULL, true);
     monitor_list_append(&mon->common);
+
+    /* monitor cannot yet be preserved across cpr */
+    chr->reopen_on_cpr = true;
 }
diff --git a/monitor/qmp.c b/monitor/qmp.c
index 092c527..0b3aac6 100644
--- a/monitor/qmp.c
+++ b/monitor/qmp.c
@@ -535,4 +535,8 @@ void monitor_init_qmp(Chardev *chr, bool pretty, Error **errp)
                                  NULL, &mon->common, NULL, true);
         monitor_list_append(&mon->common);
     }
+
+    /* Monitor cannot yet be preserved across cpr */
+    chr->reopen_on_cpr = true;
+    chr->cpr_enabled = false;
 }
-- 
1.8.3.1