/* * QEMU live migration via Unix Domain Sockets * * Copyright Red Hat, Inc. 2009 * * Authors: * Chris Lalancette <clalance@redhat.com> * * This work is licensed under the terms of the GNU GPL, version 2. See * the COPYING file in the top-level directory. * * Contributions after 2012-01-13 are licensed under the terms of the * GNU GPL, version 2 or (at your option) any later version. */ #include "qemu-common.h" #include "qemu_socket.h" #include "migration.h" #include "qemu-char.h" #include "buffered_file.h" #include "block.h" //#define DEBUG_MIGRATION_UNIX #ifdef DEBUG_MIGRATION_UNIX #define DPRINTF(fmt, ...) \ do { printf("migration-unix: " fmt, ## __VA_ARGS__); } while (0) #else #define DPRINTF(fmt, ...) \ do { } while (0) #endif static int unix_errno(MigrationState *s) { return errno; } static int unix_write(MigrationState *s, const void * buf, size_t size) { return write(s->fd, buf, size); } static int unix_close(MigrationState *s) { int r = 0; DPRINTF("unix_close\n"); if (s->fd != -1) { if (close(s->fd) < 0) { r = -errno; } s->fd = -1; } return r; } static void unix_wait_for_connect(void *opaque) { MigrationState *s = opaque; int val, ret; socklen_t valsize = sizeof(val); DPRINTF("connect completed\n"); do { ret = getsockopt(s->fd, SOL_SOCKET, SO_ERROR, (void *) &val, &valsize); } while (ret == -1 && errno == EINTR); if (ret < 0) { migrate_fd_error(s); return; } qemu_set_fd_handler2(s->fd, NULL, NULL, NULL, NULL); if (val == 0) migrate_fd_connect(s); else { DPRINTF("error connecting %d\n", val); migrate_fd_error(s); } } int unix_start_outgoing_migration(MigrationState *s, const char *path) { struct sockaddr_un addr; int ret; addr.sun_family = AF_UNIX; snprintf(addr.sun_path, sizeof(addr.sun_path), "%s", path); s->get_error = unix_errno; s->write = unix_write; s->close = unix_close; s->fd = qemu_socket(PF_UNIX, SOCK_STREAM, 0); if (s->fd == -1) { DPRINTF("Unable to open socket"); return -errno; } socket_set_nonblock(s->fd); do { ret = connect(s->fd, (struct sockaddr *)&addr, sizeof(addr)); if (ret == -1) { ret = -errno; } if (ret == -EINPROGRESS || ret == -EWOULDBLOCK) { qemu_set_fd_handler2(s->fd, NULL, NULL, unix_wait_for_connect, s); return 0; } } while (ret == -EINTR); if (ret < 0) { DPRINTF("connect failed\n"); migrate_fd_error(s); return ret; } migrate_fd_connect(s); return 0; } static void unix_accept_incoming_migration(void *opaque) { struct sockaddr_un addr; socklen_t addrlen = sizeof(addr); int s = (intptr_t)opaque; QEMUFile *f; int c; do { c = qemu_accept(s, (struct sockaddr *)&addr, &addrlen); } while (c == -1 && errno == EINTR); DPRINTF("accepted migration\n"); if (c == -1) { fprintf(stderr, "could not accept migration connection\n"); goto out2; } f = qemu_fopen_socket(c); if (f == NULL) { fprintf(stderr, "could not qemu_fopen socket\n"); goto out; } process_incoming_migration(f); qemu_fclose(f); out: close(c); out2: qemu_set_fd_handler2(s, NULL, NULL, NULL, NULL); close(s); } int unix_start_incoming_migration(const char *path) { struct sockaddr_un addr; int s; int ret; DPRINTF("Attempting to start an incoming migration\n"); s = qemu_socket(PF_UNIX, SOCK_STREAM, 0); if (s == -1) { fprintf(stderr, "Could not open unix socket: %s\n", strerror(errno)); return -errno; } memset(&addr, 0, sizeof(addr)); addr.sun_family = AF_UNIX; snprintf(addr.sun_path, sizeof(addr.sun_path), "%s", path); unlink(addr.sun_path); if (bind(s, (struct sockaddr *) &addr, sizeof(addr)) < 0) { ret = -errno; fprintf(stderr, "bind(unix:%s): %s\n", addr.sun_path, strerror(errno)); goto err; } if (listen(s, 1) == -1) { fprintf(stderr, "listen(unix:%s): %s\n", addr.sun_path, strerror(errno)); ret = -errno; goto err; } qemu_set_fd_handler2(s, NULL, unix_accept_incoming_migration, NULL, (void *)(intptr_t)s); return 0; err: close(s); return ret; }