File:  [Qemu by Fabrice Bellard] / qemu / migration-unix.c
Revision 1.1.1.3 (vendor branch): download - view: text, annotated - select for diffs
Tue Apr 24 18:55:46 2018 UTC (3 years, 1 month ago) by root
Branches: qemu, MAIN
CVS tags: qemu1000, qemu0151, HEAD
qemu 0.15.1

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

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