Annotation of qemu/migration-unix.c, revision 1.1.1.1

1.1       root        1: /*
                      2:  * QEMU live migration via Unix Domain Sockets
                      3:  *
                      4:  * Copyright Red Hat, Inc. 2009
                      5:  *
                      6:  * Authors:
                      7:  *  Chris Lalancette <clalance@redhat.com>
                      8:  *
                      9:  * This work is licensed under the terms of the GNU GPL, version 2.  See
                     10:  * the COPYING file in the top-level directory.
                     11:  *
                     12:  */
                     13: 
                     14: #include "qemu-common.h"
                     15: #include "qemu_socket.h"
                     16: #include "migration.h"
                     17: #include "qemu-char.h"
                     18: #include "sysemu.h"
                     19: #include "buffered_file.h"
                     20: #include "block.h"
                     21: 
                     22: //#define DEBUG_MIGRATION_UNIX
                     23: 
                     24: #ifdef DEBUG_MIGRATION_UNIX
                     25: #define dprintf(fmt, ...) \
                     26:     do { printf("migration-unix: " fmt, ## __VA_ARGS__); } while (0)
                     27: #else
                     28: #define dprintf(fmt, ...) \
                     29:     do { } while (0)
                     30: #endif
                     31: 
                     32: static int unix_errno(FdMigrationState *s)
                     33: {
                     34:     return errno;
                     35: }
                     36: 
                     37: static int unix_write(FdMigrationState *s, const void * buf, size_t size)
                     38: {
                     39:     return write(s->fd, buf, size);
                     40: }
                     41: 
                     42: static int unix_close(FdMigrationState *s)
                     43: {
                     44:     dprintf("unix_close\n");
                     45:     if (s->fd != -1) {
                     46:         close(s->fd);
                     47:         s->fd = -1;
                     48:     }
                     49:     return 0;
                     50: }
                     51: 
                     52: static void unix_wait_for_connect(void *opaque)
                     53: {
                     54:     FdMigrationState *s = opaque;
                     55:     int val, ret;
                     56:     socklen_t valsize = sizeof(val);
                     57: 
                     58:     dprintf("connect completed\n");
                     59:     do {
                     60:         ret = getsockopt(s->fd, SOL_SOCKET, SO_ERROR, (void *) &val, &valsize);
                     61:     } while (ret == -1 && (s->get_error(s)) == EINTR);
                     62: 
                     63:     if (ret < 0) {
                     64:         migrate_fd_error(s);
                     65:         return;
                     66:     }
                     67: 
                     68:     qemu_set_fd_handler2(s->fd, NULL, NULL, NULL, NULL);
                     69: 
                     70:     if (val == 0)
                     71:         migrate_fd_connect(s);
                     72:     else {
                     73:         dprintf("error connecting %d\n", val);
                     74:         migrate_fd_error(s);
                     75:     }
                     76: }
                     77: 
                     78: MigrationState *unix_start_outgoing_migration(Monitor *mon,
                     79:                                               const char *path,
                     80:                                              int64_t bandwidth_limit,
                     81:                                              int detach,
                     82:                                              int blk,
                     83:                                              int inc)
                     84: {
                     85:     FdMigrationState *s;
                     86:     struct sockaddr_un addr;
                     87:     int ret;
                     88: 
                     89:     addr.sun_family = AF_UNIX;
                     90:     snprintf(addr.sun_path, sizeof(addr.sun_path), "%s", path);
                     91: 
                     92:     s = qemu_mallocz(sizeof(*s));
                     93: 
                     94:     s->get_error = unix_errno;
                     95:     s->write = unix_write;
                     96:     s->close = unix_close;
                     97:     s->mig_state.cancel = migrate_fd_cancel;
                     98:     s->mig_state.get_status = migrate_fd_get_status;
                     99:     s->mig_state.release = migrate_fd_release;
                    100: 
                    101:     s->mig_state.blk = blk;
                    102:     s->mig_state.shared = inc;
                    103: 
                    104:     s->state = MIG_STATE_ACTIVE;
                    105:     s->mon = NULL;
                    106:     s->bandwidth_limit = bandwidth_limit;
                    107:     s->fd = qemu_socket(PF_UNIX, SOCK_STREAM, 0);
                    108:     if (s->fd < 0) {
                    109:         dprintf("Unable to open socket");
                    110:         goto err_after_alloc;
                    111:     }
                    112: 
                    113:     socket_set_nonblock(s->fd);
                    114: 
                    115:     do {
                    116:         ret = connect(s->fd, (struct sockaddr *)&addr, sizeof(addr));
                    117:         if (ret == -1)
                    118:            ret = -(s->get_error(s));
                    119: 
                    120:         if (ret == -EINPROGRESS || ret == -EWOULDBLOCK)
                    121:            qemu_set_fd_handler2(s->fd, NULL, NULL, unix_wait_for_connect, s);
                    122:     } while (ret == -EINTR);
                    123: 
                    124:     if (ret < 0 && ret != -EINPROGRESS && ret != -EWOULDBLOCK) {
                    125:         dprintf("connect failed\n");
                    126:         goto err_after_open;
                    127:     }
                    128: 
                    129:     if (!detach) {
                    130:         migrate_fd_monitor_suspend(s, mon);
                    131:     }
                    132: 
                    133:     if (ret >= 0)
                    134:         migrate_fd_connect(s);
                    135: 
                    136:     return &s->mig_state;
                    137: 
                    138: err_after_open:
                    139:     close(s->fd);
                    140: 
                    141: err_after_alloc:
                    142:     qemu_free(s);
                    143:     return NULL;
                    144: }
                    145: 
                    146: static void unix_accept_incoming_migration(void *opaque)
                    147: {
                    148:     struct sockaddr_un addr;
                    149:     socklen_t addrlen = sizeof(addr);
                    150:     int s = (unsigned long)opaque;
                    151:     QEMUFile *f;
                    152:     int c, ret;
                    153: 
                    154:     do {
                    155:         c = qemu_accept(s, (struct sockaddr *)&addr, &addrlen);
                    156:     } while (c == -1 && socket_error() == EINTR);
                    157: 
                    158:     dprintf("accepted migration\n");
                    159: 
                    160:     if (c == -1) {
                    161:         fprintf(stderr, "could not accept migration connection\n");
                    162:         return;
                    163:     }
                    164: 
                    165:     f = qemu_fopen_socket(c);
                    166:     if (f == NULL) {
                    167:         fprintf(stderr, "could not qemu_fopen socket\n");
                    168:         goto out;
                    169:     }
                    170: 
                    171:     ret = qemu_loadvm_state(f);
                    172:     if (ret < 0) {
                    173:         fprintf(stderr, "load of migration failed\n");
                    174:         goto out_fopen;
                    175:     }
                    176:     qemu_announce_self();
                    177:     dprintf("successfully loaded vm state\n");
                    178: 
                    179:     /* we've successfully migrated, close the server socket */
                    180:     qemu_set_fd_handler2(s, NULL, NULL, NULL, NULL);
                    181:     close(s);
                    182: 
                    183: out_fopen:
                    184:     qemu_fclose(f);
                    185: out:
                    186:     close(c);
                    187: }
                    188: 
                    189: int unix_start_incoming_migration(const char *path)
                    190: {
                    191:     struct sockaddr_un un;
                    192:     int sock;
                    193: 
                    194:     dprintf("Attempting to start an incoming migration\n");
                    195: 
                    196:     sock = qemu_socket(PF_UNIX, SOCK_STREAM, 0);
                    197:     if (sock < 0) {
                    198:         fprintf(stderr, "Could not open unix socket: %s\n", strerror(errno));
                    199:         return -EINVAL;
                    200:     }
                    201: 
                    202:     memset(&un, 0, sizeof(un));
                    203:     un.sun_family = AF_UNIX;
                    204:     snprintf(un.sun_path, sizeof(un.sun_path), "%s", path);
                    205: 
                    206:     unlink(un.sun_path);
                    207:     if (bind(sock, (struct sockaddr*) &un, sizeof(un)) < 0) {
                    208:         fprintf(stderr, "bind(unix:%s): %s\n", un.sun_path, strerror(errno));
                    209:         goto err;
                    210:     }
                    211:     if (listen(sock, 1) < 0) {
                    212:         fprintf(stderr, "listen(unix:%s): %s\n", un.sun_path, strerror(errno));
                    213:         goto err;
                    214:     }
                    215: 
                    216:     qemu_set_fd_handler2(sock, NULL, unix_accept_incoming_migration, NULL,
                    217:                         (void *)(unsigned long)sock);
                    218: 
                    219:     return 0;
                    220: 
                    221: err:
                    222:     close(sock);
                    223: 
                    224:     return -EINVAL;
                    225: }

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