migration-fd.c

   1 /*
   2  * QEMU live migration via generic fd
   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 "monitor.h"
  18 #include "qemu-char.h"
  19 #include "sysemu.h"
  20 #include "buffered_file.h"
  21 #include "block.h"
  22 #include "qemu_socket.h"
  23
  24 //#define DEBUG_MIGRATION_FD
  25
  26 #ifdef DEBUG_MIGRATION_FD
  27 #define dprintf(fmt, ...) \
  28     do { printf("migration-fd: " fmt, ## __VA_ARGS__); } while (0)
  29 #else
  30 #define dprintf(fmt, ...) \
  31     do { } while (0)
  32 #endif
  33
  34 static int fd_errno(FdMigrationState *s)
  35 {
  36     return errno;
  37 }
  38
  39 static int fd_write(FdMigrationState *s, const void * buf, size_t size)
  40 {
  41     return write(s->fd, buf, size);
  42 }
  43
  44 static int fd_close(FdMigrationState *s)
  45 {
  46     dprintf("fd_close\n");
  47     if (s->fd != -1) {
  48         close(s->fd);
  49         s->fd = -1;
  50     }
  51     return 0;
  52 }
  53
  54 MigrationState *fd_start_outgoing_migration(Monitor *mon,
  55                                             const char *fdname,
  56                                             int64_t bandwidth_limit,
  57                                             int detach)
  58 {
  59     FdMigrationState *s;
  60
  61     s = qemu_mallocz(sizeof(*s));
  62
  63     s->fd = monitor_get_fd(mon, fdname);
  64     if (s->fd == -1) {
  65         dprintf("fd_migration: invalid file descriptor identifier\n");
  66         goto err_after_alloc;
  67     }
  68
  69     if (fcntl(s->fd, F_SETFL, O_NONBLOCK) == -1) {
  70         dprintf("Unable to set nonblocking mode on file descriptor\n");
  71         goto err_after_open;
  72     }
  73
  74     s->get_error = fd_errno;
  75     s->write = fd_write;
  76     s->close = fd_close;
  77     s->mig_state.cancel = migrate_fd_cancel;
  78     s->mig_state.get_status = migrate_fd_get_status;
  79     s->mig_state.release = migrate_fd_release;
  80
  81     s->state = MIG_STATE_ACTIVE;
  82     s->mon_resume = NULL;
  83     s->bandwidth_limit = bandwidth_limit;
  84
  85     if (!detach)
  86         migrate_fd_monitor_suspend(s);
  87
  88     migrate_fd_connect(s);
  89     return &s->mig_state;
  90
  91 err_after_open:
  92     close(s->fd);
  93 err_after_alloc:
  94     qemu_free(s);
  95     return NULL;
  96 }
  97
  98 static void fd_accept_incoming_migration(void *opaque)
  99 {
 100     QEMUFile *f = opaque;
 101     int ret;
 102
 103     ret = qemu_loadvm_state(f);
 104     if (ret < 0) {
 105         fprintf(stderr, "load of migration failed\n");
 106         goto err;
 107     }
 108     qemu_announce_self();
 109     dprintf("successfully loaded vm state\n");
 110     /* we've successfully migrated, close the fd */
 111     qemu_set_fd_handler2(qemu_stdio_fd(f), NULL, NULL, NULL, NULL);
 112     if (autostart)
 113         vm_start();
 114
 115 err:
 116     qemu_fclose(f);
 117 }
 118
 119 int fd_start_incoming_migration(const char *infd)
 120 {
 121     int fd;
 122     QEMUFile *f;
 123
 124     dprintf("Attempting to start an incoming migration via fd\n");
 125
 126     fd = strtol(infd, NULL, 0);
 127     f = qemu_fdopen(fd, "rb");
 128     if(f == NULL) {
 129         dprintf("Unable to apply qemu wrapper to file descriptor\n");
 130         return -errno;
 131     }
 132
 133     qemu_set_fd_handler2(fd, NULL, fd_accept_incoming_migration, NULL,
 134                          (void *)(unsigned long)f);
 135
 136     return 0;
 137 }