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authorCristian Klein <cristian.klein@cs.umu.se>2015-01-08 11:11:31 +0000
committerAmit Shah <amit.shah@redhat.com>2015-01-16 13:06:17 +0530
commit131fe9b843f9a1e55fcbf2457c9cb25c3711b9d8 (patch)
treec6e9872e69799afe33dd960cdfcf9a743df48a4e
parente1a8c9b67fc97d293211773edcae9e8e2f3367ab (diff)
Handle bi-directional communication for fd migration
libvirt prefers opening the TCP connection itself, for two reasons. First, connection failed errors can be detected easier, without having to parse qemu's error output. Second, libvirt might be asked to secure the transfer by tunnelling the communication through an TLS layer. Therefore, libvirt opens the TCP connection itself and passes an FD to qemu using QMP and a POSIX-specific mechanism. Hence, in order to make the reverse-path work in such cases, qemu needs to distinguish if the transmitted FD is a socket (reverse-path available) or not (reverse-path might not be available) and use the corresponding abstraction. Signed-off-by: Cristian Klein <cristian.klein@cs.umu.se> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Amit Shah <amit.shah@redhat.com> Signed-off-by: Amit Shah <amit.shah@redhat.com>
-rw-r--r--migration/fd.c24
1 files changed, 22 insertions, 2 deletions
diff --git a/migration/fd.c b/migration/fd.c
index d2e523af74..129da9910b 100644
--- a/migration/fd.c
+++ b/migration/fd.c
@@ -31,13 +31,29 @@
do { } while (0)
#endif
+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);
+}
+
void fd_start_outgoing_migration(MigrationState *s, const char *fdname, Error **errp)
{
int fd = monitor_get_fd(cur_mon, fdname, errp);
if (fd == -1) {
return;
}
- s->file = qemu_fdopen(fd, "wb");
+
+ if (fd_is_socket(fd)) {
+ s->file = qemu_fopen_socket(fd, "wb");
+ } else {
+ s->file = qemu_fdopen(fd, "wb");
+ }
migrate_fd_connect(s);
}
@@ -58,7 +74,11 @@ void fd_start_incoming_migration(const char *infd, Error **errp)
DPRINTF("Attempting to start an incoming migration via fd\n");
fd = strtol(infd, NULL, 0);
- f = qemu_fdopen(fd, "rb");
+ if (fd_is_socket(fd)) {
+ f = qemu_fopen_socket(fd, "rb");
+ } else {
+ f = qemu_fdopen(fd, "rb");
+ }
if(f == NULL) {
error_setg_errno(errp, errno, "failed to open the source descriptor");
return;