File:  [Qemu by Fabrice Bellard] / qemu / migration-unix.c
Revision 1.1.1.2 (vendor branch): download - view: text, annotated - select for diffs
Tue Apr 24 18:23:23 2018 UTC (3 years, 1 month ago) by root
Branches: qemu, MAIN
CVS tags: qemu0150, qemu0141, qemu0140, qemu0130, HEAD
qemu 0.13.0

    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;
  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:     process_incoming_migration(f);
  172:     qemu_fclose(f);
  173: out:
  174:     qemu_set_fd_handler2(s, NULL, NULL, NULL, NULL);
  175:     close(s);
  176:     close(c);
  177: }
  178: 
  179: int unix_start_incoming_migration(const char *path)
  180: {
  181:     struct sockaddr_un un;
  182:     int sock;
  183: 
  184:     DPRINTF("Attempting to start an incoming migration\n");
  185: 
  186:     sock = qemu_socket(PF_UNIX, SOCK_STREAM, 0);
  187:     if (sock < 0) {
  188:         fprintf(stderr, "Could not open unix socket: %s\n", strerror(errno));
  189:         return -EINVAL;
  190:     }
  191: 
  192:     memset(&un, 0, sizeof(un));
  193:     un.sun_family = AF_UNIX;
  194:     snprintf(un.sun_path, sizeof(un.sun_path), "%s", path);
  195: 
  196:     unlink(un.sun_path);
  197:     if (bind(sock, (struct sockaddr*) &un, sizeof(un)) < 0) {
  198:         fprintf(stderr, "bind(unix:%s): %s\n", un.sun_path, strerror(errno));
  199:         goto err;
  200:     }
  201:     if (listen(sock, 1) < 0) {
  202:         fprintf(stderr, "listen(unix:%s): %s\n", un.sun_path, strerror(errno));
  203:         goto err;
  204:     }
  205: 
  206:     qemu_set_fd_handler2(sock, NULL, unix_accept_incoming_migration, NULL,
  207: 			 (void *)(unsigned long)sock);
  208: 
  209:     return 0;
  210: 
  211: err:
  212:     close(sock);
  213: 
  214:     return -EINVAL;
  215: }

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