[PATCH V5 23/25] chardev: cpr for sockets

[Steve Sistare]

Save accepted socket fds in the environment before cprsave, and look for
fds in the environment after cprload.  Reject cprexec 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 | 31 +++++++++++++++++++++++++++++++
 monitor/hmp.c         |  3 +++
 monitor/qmp.c         |  3 +++
 3 files changed, 37 insertions(+)

diff --git a/chardev/char-socket.c b/chardev/char-socket.c
index d0fb545..dc9da8c 100644
--- a/chardev/char-socket.c
+++ b/chardev/char-socket.c
@@ -27,7 +27,9 @@
 #include "io/channel-socket.h"
 #include "io/channel-tls.h"
 #include "io/channel-websock.h"
+#include "qemu/env.h"
 #include "io/net-listener.h"
+#include "qemu/env.h"
 #include "qemu/error-report.h"
 #include "qemu/module.h"
 #include "qemu/option.h"
@@ -414,6 +416,7 @@ 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]);
@@ -976,6 +979,10 @@ static void tcp_chr_accept(QIONetListener *listener,
                                QIO_CHANNEL(cioc));
     }
     tcp_chr_new_client(chr, cioc);
+
+    if (s->sioc && !chr->close_on_cpr) {
+        setenv_fd(chr->label, s->sioc->fd);
+    }
 }
 
 
@@ -1231,6 +1238,24 @@ static gboolean socket_reconnect_timeout(gpointer opaque)
     return false;
 }
 
+static void load_char_socket_fd(Chardev *chr, Error **errp)
+{
+    SocketChardev *sockchar = SOCKET_CHARDEV(chr);
+    QIOChannelSocket *sioc;
+    int fd = getenv_fd(chr->label);
+
+    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_setg(errp, "error: could not restore socket for %s",
+                       chr->label);
+        }
+    }
+}
 
 static int qmp_chardev_open_socket_server(Chardev *chr,
                                           bool is_telnet,
@@ -1435,6 +1460,10 @@ 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);
+    }
+
     /* be isn't opened until we get a connection */
     *be_opened = false;
 
@@ -1450,6 +1479,8 @@ 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/monitor/hmp.c b/monitor/hmp.c
index 6c0b33a..63700b3 100644
--- a/monitor/hmp.c
+++ b/monitor/hmp.c
@@ -1451,4 +1451,7 @@ 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->close_on_cpr = true;
 }
diff --git a/monitor/qmp.c b/monitor/qmp.c
index 092c527..21a90bf 100644
--- a/monitor/qmp.c
+++ b/monitor/qmp.c
@@ -535,4 +535,7 @@ 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->close_on_cpr = true;
 }
-- 
1.8.3.1