File:  [Qemu by Fabrice Bellard] / qemu / migration-unix.c
Revision 1.1.1.4 (vendor branch): download - view: text, annotated - select for diffs
Tue Apr 24 19:16:50 2018 UTC (2 years, 4 months ago) by root
Branches: qemu, MAIN
CVS tags: qemu1001, HEAD
qemu 1.0.1

    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(MigrationState *s)
   32: {
   33:     return errno;
   34: }
   35: 
   36: static int unix_write(MigrationState *s, const void * buf, size_t size)
   37: {
   38:     return write(s->fd, buf, size);
   39: }
   40: 
   41: static int unix_close(MigrationState *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:     MigrationState *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 && errno == 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: int unix_start_outgoing_migration(MigrationState *s, const char *path)
   78: {
   79:     struct sockaddr_un addr;
   80:     int ret;
   81: 
   82:     addr.sun_family = AF_UNIX;
   83:     snprintf(addr.sun_path, sizeof(addr.sun_path), "%s", path);
   84:     s->get_error = unix_errno;
   85:     s->write = unix_write;
   86:     s->close = unix_close;
   87: 
   88:     s->fd = qemu_socket(PF_UNIX, SOCK_STREAM, 0);
   89:     if (s->fd == -1) {
   90:         DPRINTF("Unable to open socket");
   91:         return -errno;
   92:     }
   93: 
   94:     socket_set_nonblock(s->fd);
   95: 
   96:     do {
   97:         ret = connect(s->fd, (struct sockaddr *)&addr, sizeof(addr));
   98:         if (ret == -1) {
   99:             ret = -errno;
  100:         }
  101:         if (ret == -EINPROGRESS || ret == -EWOULDBLOCK) {
  102: 	    qemu_set_fd_handler2(s->fd, NULL, NULL, unix_wait_for_connect, s);
  103:             return 0;
  104:         }
  105:     } while (ret == -EINTR);
  106: 
  107:     if (ret < 0) {
  108:         DPRINTF("connect failed\n");
  109:         migrate_fd_error(s);
  110:         return ret;
  111:     }
  112:     migrate_fd_connect(s);
  113:     return 0;
  114: }
  115: 
  116: static void unix_accept_incoming_migration(void *opaque)
  117: {
  118:     struct sockaddr_un addr;
  119:     socklen_t addrlen = sizeof(addr);
  120:     int s = (intptr_t)opaque;
  121:     QEMUFile *f;
  122:     int c;
  123: 
  124:     do {
  125:         c = qemu_accept(s, (struct sockaddr *)&addr, &addrlen);
  126:     } while (c == -1 && errno == EINTR);
  127: 
  128:     DPRINTF("accepted migration\n");
  129: 
  130:     if (c == -1) {
  131:         fprintf(stderr, "could not accept migration connection\n");
  132:         goto out2;
  133:     }
  134: 
  135:     f = qemu_fopen_socket(c);
  136:     if (f == NULL) {
  137:         fprintf(stderr, "could not qemu_fopen socket\n");
  138:         goto out;
  139:     }
  140: 
  141:     process_incoming_migration(f);
  142:     qemu_fclose(f);
  143: out:
  144:     close(c);
  145: out2:
  146:     qemu_set_fd_handler2(s, NULL, NULL, NULL, NULL);
  147:     close(s);
  148: }
  149: 
  150: int unix_start_incoming_migration(const char *path)
  151: {
  152:     struct sockaddr_un addr;
  153:     int s;
  154:     int ret;
  155: 
  156:     DPRINTF("Attempting to start an incoming migration\n");
  157: 
  158:     s = qemu_socket(PF_UNIX, SOCK_STREAM, 0);
  159:     if (s == -1) {
  160:         fprintf(stderr, "Could not open unix socket: %s\n", strerror(errno));
  161:         return -errno;
  162:     }
  163: 
  164:     memset(&addr, 0, sizeof(addr));
  165:     addr.sun_family = AF_UNIX;
  166:     snprintf(addr.sun_path, sizeof(addr.sun_path), "%s", path);
  167: 
  168:     unlink(addr.sun_path);
  169:     if (bind(s, (struct sockaddr *) &addr, sizeof(addr)) < 0) {
  170:         ret = -errno;
  171:         fprintf(stderr, "bind(unix:%s): %s\n", addr.sun_path, strerror(errno));
  172:         goto err;
  173:     }
  174:     if (listen(s, 1) == -1) {
  175:         fprintf(stderr, "listen(unix:%s): %s\n", addr.sun_path,
  176:                 strerror(errno));
  177:         ret = -errno;
  178:         goto err;
  179:     }
  180: 
  181:     qemu_set_fd_handler2(s, NULL, unix_accept_incoming_migration, NULL,
  182:                          (void *)(intptr_t)s);
  183: 
  184:     return 0;
  185: 
  186: err:
  187:     close(s);
  188:     return ret;
  189: }

unix.superglobalmegacorp.com