[RFC PATCH 09/20] Introduce writev and read to FdMigrationState.

[Yoshiaki Tamura <tamura.yoshiaki@xxxxxxxxxxxxx>]

Currently FdMigrationState doesn't support writev() and read().
writev() is introduced to send data efficiently, and read() is
necessary to get response from the other side.

Signed-off-by: Yoshiaki Tamura <tamura.yoshiaki@xxxxxxxxxxxxx>
---
 migration-tcp.c |   20 ++++++++++++++++++++
 migration.c     |   27 +++++++++++++++++++++++++++
 migration.h     |    6 ++++++
 3 files changed, 53 insertions(+), 0 deletions(-)

diff --git a/migration-tcp.c b/migration-tcp.c
index e7f307c..56e1a3b 100644
--- a/migration-tcp.c
+++ b/migration-tcp.c
@@ -39,6 +39,24 @@ static int socket_write(FdMigrationState *s, const void * buf, size_t size)
     return send(s->fd, buf, size, 0);
 }
 
+static int socket_read(FdMigrationState *s, const void * buf, size_t size)
+{
+    ssize_t len;
+
+    do { 
+        len = recv(s->fd, (void *)buf, size, 0);
+    } while (len == -1 && socket_error() == EINTR);
+    if (len == -1)
+        len = -socket_error();
+
+    return len;
+}
+
+static int socket_writev(FdMigrationState *s, const struct iovec *v, int count)
+{
+    return writev(s->fd, v, count);
+}
+
 static int tcp_close(FdMigrationState *s)
 {
     DPRINTF("tcp_close\n");
@@ -94,6 +112,8 @@ MigrationState *tcp_start_outgoing_migration(Monitor *mon,
 
     s->get_error = socket_errno;
     s->write = socket_write;
+    s->writev = socket_writev;
+    s->read = socket_read;
     s->close = tcp_close;
     s->mig_state.cancel = migrate_fd_cancel;
     s->mig_state.get_status = migrate_fd_get_status;
diff --git a/migration.c b/migration.c
index 05f6cc5..5d238f5 100644
--- a/migration.c
+++ b/migration.c
@@ -337,6 +337,33 @@ ssize_t migrate_fd_put_buffer(void *opaque, const void *data, size_t size)
     return ret;
 }
 
+int migrate_fd_get_buffer(void *opaque, uint8_t *data, int64_t pos, int size)
+{
+    FdMigrationState *s = opaque;
+    ssize_t ret;
+    ret = s->read(s, data, size);
+    
+    if (ret == -1)
+        ret = -(s->get_error(s));
+    
+    return ret;
+}
+
+ssize_t migrate_fd_put_vector(void *opaque, const struct iovec *vector, int count)
+{
+    FdMigrationState *s = opaque;
+    ssize_t ret;
+
+    do {
+        ret = s->writev(s, vector, count);
+    } while (ret == -1 && ((s->get_error(s)) == EINTR));
+
+    if (ret == -1)
+        ret = -(s->get_error(s));
+
+    return ret;
+}
+
 void migrate_fd_connect(FdMigrationState *s)
 {
     int ret;
diff --git a/migration.h b/migration.h
index 385423f..ddc1d42 100644
--- a/migration.h
+++ b/migration.h
@@ -47,6 +47,8 @@ struct FdMigrationState
     int (*get_error)(struct FdMigrationState*);
     int (*close)(struct FdMigrationState*);
     int (*write)(struct FdMigrationState*, const void *, size_t);
+    int (*writev)(struct FdMigrationState*, const struct iovec *, int);
+    int (*read)(struct FdMigrationState *, const void *, size_t);
     void *opaque;
 };
 
@@ -113,6 +115,10 @@ void migrate_fd_put_notify(void *opaque);
 
 ssize_t migrate_fd_put_buffer(void *opaque, const void *data, size_t size);
 
+ssize_t migrate_fd_put_vector(void *opaque, const struct iovec *iov, int count);
+
+int migrate_fd_get_buffer(void *opaque, uint8_t *data, int64_t pos, int size);
+
 void migrate_fd_connect(FdMigrationState *s);
 
 void migrate_fd_put_ready(void *opaque);
-- 
1.7.0.31.g1df487

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