[PATCH 02/18] Introduce read() to FdMigrationState.

[OHMURA Kei <ohmura.kei@xxxxxxxxxxxxx>]

From: Yoshiaki Tamura <tamura.yoshiaki@xxxxxxxxxxxxx>

Currently FdMigrationState doesn't support read(), and this patch
introduces it to get response from the other side.  Note that this
won't change the existing migration protocol to be bi-directional.

Signed-off-by: Yoshiaki Tamura <tamura.yoshiaki@xxxxxxxxxxxxx>
Signed-off-by: OHMURA Kei <ohmura.kei@xxxxxxxxxxxxx>
---
 migration-tcp.c |   15 +++++++++++++++
 migration.c     |   13 +++++++++++++
 migration.h     |    3 +++
 3 files changed, 31 insertions(+), 0 deletions(-)

diff --git a/migration-tcp.c b/migration-tcp.c
index d3d80c9..bb67d53 100644
--- a/migration-tcp.c
+++ b/migration-tcp.c
@@ -38,6 +38,20 @@ 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 tcp_close(FdMigrationState *s)
 {
     DPRINTF("tcp_close\n");
@@ -93,6 +107,7 @@ MigrationState *tcp_start_outgoing_migration(Monitor *mon,
 
     s->get_error = socket_errno;
     s->write = socket_write;
+    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 af3a1f2..302b8fe 100644
--- a/migration.c
+++ b/migration.c
@@ -340,6 +340,19 @@ 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, size_t size)
+{
+    FdMigrationState *s = opaque;
+    int ret;
+
+    ret = s->read(s, data, size);
+    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 050c56c..6a76f77 100644
--- a/migration.h
+++ b/migration.h
@@ -48,6 +48,7 @@ struct FdMigrationState
     int (*get_error)(struct FdMigrationState*);
     int (*close)(struct FdMigrationState*);
     int (*write)(struct FdMigrationState*, const void *, size_t);
+    int (*read)(struct FdMigrationState *, const void *, size_t);
     void *opaque;
 };
 
@@ -116,6 +117,8 @@ void migrate_fd_put_notify(void *opaque);
 
 ssize_t migrate_fd_put_buffer(void *opaque, const void *data, size_t size);
 
+int migrate_fd_get_buffer(void *opaque, uint8_t *data, int64_t pos, size_t size);
+
 void migrate_fd_connect(FdMigrationState *s);
 
 void migrate_fd_put_ready(void *opaque);
-- 
1.7.0.2

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