File:  [Qemu by Fabrice Bellard] / qemu / migration-unix.c
Revision 1.1.1.5 (vendor branch): download - view: text, annotated - select for diffs
Tue Apr 24 19:33:52 2018 UTC (2 years, 4 months ago) by root
Branches: qemu, MAIN
CVS tags: qemu1101, HEAD
qemu 1.1.1

    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:  * Contributions after 2012-01-13 are licensed under the terms of the
   13:  * GNU GPL, version 2 or (at your option) any later version.
   14:  */
   15: 
   16: #include "qemu-common.h"
   17: #include "qemu_socket.h"
   18: #include "migration.h"
   19: #include "qemu-char.h"
   20: #include "buffered_file.h"
   21: #include "block.h"
   22: 
   23: //#define DEBUG_MIGRATION_UNIX
   24: 
   25: #ifdef DEBUG_MIGRATION_UNIX
   26: #define DPRINTF(fmt, ...) \
   27:     do { printf("migration-unix: " fmt, ## __VA_ARGS__); } while (0)
   28: #else
   29: #define DPRINTF(fmt, ...) \
   30:     do { } while (0)
   31: #endif
   32: 
   33: static int unix_errno(MigrationState *s)
   34: {
   35:     return errno;
   36: }
   37: 
   38: static int unix_write(MigrationState *s, const void * buf, size_t size)
   39: {
   40:     return write(s->fd, buf, size);
   41: }
   42: 
   43: static int unix_close(MigrationState *s)
   44: {
   45:     int r = 0;
   46:     DPRINTF("unix_close\n");
   47:     if (s->fd != -1) {
   48:         if (close(s->fd) < 0) {
   49:             r = -errno;
   50:         }
   51:         s->fd = -1;
   52:     }
   53:     return r;
   54: }
   55: 
   56: static void unix_wait_for_connect(void *opaque)
   57: {
   58:     MigrationState *s = opaque;
   59:     int val, ret;
   60:     socklen_t valsize = sizeof(val);
   61: 
   62:     DPRINTF("connect completed\n");
   63:     do {
   64:         ret = getsockopt(s->fd, SOL_SOCKET, SO_ERROR, (void *) &val, &valsize);
   65:     } while (ret == -1 && errno == EINTR);
   66: 
   67:     if (ret < 0) {
   68:         migrate_fd_error(s);
   69:         return;
   70:     }
   71: 
   72:     qemu_set_fd_handler2(s->fd, NULL, NULL, NULL, NULL);
   73: 
   74:     if (val == 0)
   75:         migrate_fd_connect(s);
   76:     else {
   77:         DPRINTF("error connecting %d\n", val);
   78:         migrate_fd_error(s);
   79:     }
   80: }
   81: 
   82: int unix_start_outgoing_migration(MigrationState *s, const char *path)
   83: {
   84:     struct sockaddr_un addr;
   85:     int ret;
   86: 
   87:     addr.sun_family = AF_UNIX;
   88:     snprintf(addr.sun_path, sizeof(addr.sun_path), "%s", path);
   89:     s->get_error = unix_errno;
   90:     s->write = unix_write;
   91:     s->close = unix_close;
   92: 
   93:     s->fd = qemu_socket(PF_UNIX, SOCK_STREAM, 0);
   94:     if (s->fd == -1) {
   95:         DPRINTF("Unable to open socket");
   96:         return -errno;
   97:     }
   98: 
   99:     socket_set_nonblock(s->fd);
  100: 
  101:     do {
  102:         ret = connect(s->fd, (struct sockaddr *)&addr, sizeof(addr));
  103:         if (ret == -1) {
  104:             ret = -errno;
  105:         }
  106:         if (ret == -EINPROGRESS || ret == -EWOULDBLOCK) {
  107: 	    qemu_set_fd_handler2(s->fd, NULL, NULL, unix_wait_for_connect, s);
  108:             return 0;
  109:         }
  110:     } while (ret == -EINTR);
  111: 
  112:     if (ret < 0) {
  113:         DPRINTF("connect failed\n");
  114:         migrate_fd_error(s);
  115:         return ret;
  116:     }
  117:     migrate_fd_connect(s);
  118:     return 0;
  119: }
  120: 
  121: static void unix_accept_incoming_migration(void *opaque)
  122: {
  123:     struct sockaddr_un addr;
  124:     socklen_t addrlen = sizeof(addr);
  125:     int s = (intptr_t)opaque;
  126:     QEMUFile *f;
  127:     int c;
  128: 
  129:     do {
  130:         c = qemu_accept(s, (struct sockaddr *)&addr, &addrlen);
  131:     } while (c == -1 && errno == EINTR);
  132: 
  133:     DPRINTF("accepted migration\n");
  134: 
  135:     if (c == -1) {
  136:         fprintf(stderr, "could not accept migration connection\n");
  137:         goto out2;
  138:     }
  139: 
  140:     f = qemu_fopen_socket(c);
  141:     if (f == NULL) {
  142:         fprintf(stderr, "could not qemu_fopen socket\n");
  143:         goto out;
  144:     }
  145: 
  146:     process_incoming_migration(f);
  147:     qemu_fclose(f);
  148: out:
  149:     close(c);
  150: out2:
  151:     qemu_set_fd_handler2(s, NULL, NULL, NULL, NULL);
  152:     close(s);
  153: }
  154: 
  155: int unix_start_incoming_migration(const char *path)
  156: {
  157:     struct sockaddr_un addr;
  158:     int s;
  159:     int ret;
  160: 
  161:     DPRINTF("Attempting to start an incoming migration\n");
  162: 
  163:     s = qemu_socket(PF_UNIX, SOCK_STREAM, 0);
  164:     if (s == -1) {
  165:         fprintf(stderr, "Could not open unix socket: %s\n", strerror(errno));
  166:         return -errno;
  167:     }
  168: 
  169:     memset(&addr, 0, sizeof(addr));
  170:     addr.sun_family = AF_UNIX;
  171:     snprintf(addr.sun_path, sizeof(addr.sun_path), "%s", path);
  172: 
  173:     unlink(addr.sun_path);
  174:     if (bind(s, (struct sockaddr *) &addr, sizeof(addr)) < 0) {
  175:         ret = -errno;
  176:         fprintf(stderr, "bind(unix:%s): %s\n", addr.sun_path, strerror(errno));
  177:         goto err;
  178:     }
  179:     if (listen(s, 1) == -1) {
  180:         fprintf(stderr, "listen(unix:%s): %s\n", addr.sun_path,
  181:                 strerror(errno));
  182:         ret = -errno;
  183:         goto err;
  184:     }
  185: 
  186:     qemu_set_fd_handler2(s, NULL, unix_accept_incoming_migration, NULL,
  187:                          (void *)(intptr_t)s);
  188: 
  189:     return 0;
  190: 
  191: err:
  192:     close(s);
  193:     return ret;
  194: }

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