[Qemu-devel] [PATCH FYI 39/46] migration: convert fd socket protocol to use QIOChannel

["Daniel P. Berrange" <berrange@redhat.com>]

Convert the fd socket migration protocol driver to use
QIOChannel and QEMUFileChannel, instead of plain sockets
APIs. It can be unconditionally built because the
QIOChannel APIs it uses will take care to report suitable
error messages if needed.

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
---
 migration/Makefile.objs |  4 ++--
 migration/fd.c          | 57 ++++++++++++++++++++++++++++++++-----------------
 migration/migration.c   |  4 ----
 3 files changed, 39 insertions(+), 26 deletions(-)

diff --git a/migration/Makefile.objs b/migration/Makefile.objs
index 521a83b..2d1d8cd 100644
--- a/migration/Makefile.objs
+++ b/migration/Makefile.objs
@@ -1,11 +1,11 @@
-common-obj-y += migration.o tcp.o unix.o
+common-obj-y += migration.o tcp.o unix.o fd.o
 common-obj-y += vmstate.o
 common-obj-y += qemu-file.o qemu-file-unix.o qemu-file-stdio.o
 common-obj-y += qemu-file-channel.o
 common-obj-y += xbzrle.o
 
 common-obj-$(CONFIG_RDMA) += rdma.o
-common-obj-$(CONFIG_POSIX) += exec.o fd.o
+common-obj-$(CONFIG_POSIX) += exec.o
 
 common-obj-y += block.o
 
diff --git a/migration/fd.c b/migration/fd.c
index 3e4bed0..8d48e0d 100644
--- a/migration/fd.c
+++ b/migration/fd.c
@@ -20,6 +20,8 @@
 #include "monitor/monitor.h"
 #include "migration/qemu-file.h"
 #include "block/block.h"
+#include "io/channel-file.h"
+#include "io/channel-socket.h"
 
 //#define DEBUG_MIGRATION_FD
 
@@ -33,56 +35,71 @@
 
 static bool fd_is_socket(int fd)
 {
-    struct stat stat;
-    int ret = fstat(fd, &stat);
-    if (ret == -1) {
-        /* When in doubt say no */
-        return false;
-    }
-    return S_ISSOCK(stat.st_mode);
+    int optval;
+    socklen_t optlen;
+    optlen = sizeof(optval);
+    return getsockopt(fd,
+                      SOL_SOCKET,
+                      SO_TYPE,
+                      (char *)&optval,
+                      &optlen) == 0;
 }
 
 void fd_start_outgoing_migration(MigrationState *s, const char *fdname, Error **errp)
 {
+    QIOChannel *ioc;
     int fd = monitor_get_fd(cur_mon, fdname, errp);
     if (fd == -1) {
         return;
     }
 
     if (fd_is_socket(fd)) {
-        s->file = qemu_fopen_socket(fd, "wb");
+        ioc = QIO_CHANNEL(qio_channel_socket_new_fd(fd, errp));
+        if (!ioc) {
+            close(fd);
+            return;
+        }
     } else {
-        s->file = qemu_fdopen(fd, "wb");
+        ioc = QIO_CHANNEL(qio_channel_file_new_fd(fd));
     }
+    s->file = qemu_fopen_channel_output(ioc);
 
     migrate_fd_connect(s);
 }
 
-static void fd_accept_incoming_migration(void *opaque)
+static gboolean fd_accept_incoming_migration(QIOChannel *ioc,
+                                             GIOCondition condition,
+                                             gpointer opaque)
 {
     QEMUFile *f = opaque;
-
-    qemu_set_fd_handler(qemu_get_fd(f), NULL, NULL, NULL);
     process_incoming_migration(f);
+    return FALSE;
 }
 
 void fd_start_incoming_migration(const char *infd, Error **errp)
 {
-    int fd;
     QEMUFile *f;
+    QIOChannel *ioc;
+    int fd;
 
     DPRINTF("Attempting to start an incoming migration via fd\n");
 
     fd = strtol(infd, NULL, 0);
     if (fd_is_socket(fd)) {
-        f = qemu_fopen_socket(fd, "rb");
+        ioc = QIO_CHANNEL(qio_channel_socket_new_fd(fd, errp));
+        if (!ioc) {
+            close(fd);
+            return;
+        }
     } else {
-        f = qemu_fdopen(fd, "rb");
-    }
-    if(f == NULL) {
-        error_setg_errno(errp, errno, "failed to open the source descriptor");
-        return;
+        ioc = QIO_CHANNEL(qio_channel_file_new_fd(fd));
     }
+    f = qemu_fopen_channel_input(ioc);
+    object_unref(OBJECT(ioc));
 
-    qemu_set_fd_handler(fd, fd_accept_incoming_migration, NULL, f);
+    qio_channel_add_watch(ioc,
+                          G_IO_IN,
+                          fd_accept_incoming_migration,
+                          f,
+                          NULL);
 }
diff --git a/migration/migration.c b/migration/migration.c
index bd7024f..f8cf8dc 100644
--- a/migration/migration.c
+++ b/migration/migration.c
@@ -259,10 +259,8 @@ void qemu_start_incoming_migration(const char *uri, Error **errp)
 #endif
     } else if (strstart(uri, "unix:", &p)) {
         unix_start_incoming_migration(p, errp);
-#if !defined(WIN32)
     } else if (strstart(uri, "fd:", &p)) {
         fd_start_incoming_migration(p, errp);
-#endif
     } else {
         error_setg(errp, "unknown migration protocol: %s", uri);
     }
@@ -752,10 +750,8 @@ void qmp_migrate(const char *uri, bool has_blk, bool blk,
 #endif
     } else if (strstart(uri, "unix:", &p)) {
         unix_start_outgoing_migration(s, p, &local_err);
-#if !defined(WIN32)
     } else if (strstart(uri, "fd:", &p)) {
         fd_start_outgoing_migration(s, p, &local_err);
-#endif
     } else {
         error_setg(errp, QERR_INVALID_PARAMETER_VALUE, "uri",
                    "a valid migration protocol");
-- 
2.4.3