LXR qemu/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 * 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 "monitor.h"
  20#include "qemu-char.h"
  21#include "buffered_file.h"
  22#include "block.h"
  23#include "qemu_socket.h"
  24
  25//#define DEBUG_MIGRATION_FD
  26
  27#ifdef DEBUG_MIGRATION_FD
  28#define DPRINTF(fmt, ...) \
  29    do { printf("migration-fd: " fmt, ## __VA_ARGS__); } while (0)
  30#else
  31#define DPRINTF(fmt, ...) \
  32    do { } while (0)
  33#endif
  34
  35static int fd_errno(MigrationState *s)
  36{
  37    return errno;
  38}
  39
  40static int fd_write(MigrationState *s, const void * buf, size_t size)
  41{
  42    return write(s->fd, buf, size);
  43}
  44
  45static int fd_close(MigrationState *s)
  46{
  47    struct stat st;
  48    int ret;
  49
  50    DPRINTF("fd_close\n");
  51    if (s->fd != -1) {
  52        ret = fstat(s->fd, &st);
  53        if (ret == 0 && S_ISREG(st.st_mode)) {
  54            /*
  55             * If the file handle is a regular file make sure the
  56             * data is flushed to disk before signaling success.
  57             */
  58            ret = fsync(s->fd);
  59            if (ret != 0) {
  60                ret = -errno;
  61                perror("migration-fd: fsync");
  62                return ret;
  63            }
  64        }
  65        ret = close(s->fd);
  66        s->fd = -1;
  67        if (ret != 0) {
  68            ret = -errno;
  69            perror("migration-fd: close");
  70            return ret;
  71        }
  72    }
  73    return 0;
  74}
  75
  76int fd_start_outgoing_migration(MigrationState *s, const char *fdname)
  77{
  78    s->fd = monitor_get_fd(cur_mon, fdname);
  79    if (s->fd == -1) {
  80        DPRINTF("fd_migration: invalid file descriptor identifier\n");
  81        goto err_after_get_fd;
  82    }
  83
  84    if (fcntl(s->fd, F_SETFL, O_NONBLOCK) == -1) {
  85        DPRINTF("Unable to set nonblocking mode on file descriptor\n");
  86        goto err_after_open;
  87    }
  88
  89    s->get_error = fd_errno;
  90    s->write = fd_write;
  91    s->close = fd_close;
  92
  93    migrate_fd_connect(s);
  94    return 0;
  95
  96err_after_open:
  97    close(s->fd);
  98err_after_get_fd:
  99    return -1;
 100}
 101
 102static void fd_accept_incoming_migration(void *opaque)
 103{
 104    QEMUFile *f = opaque;
 105
 106    process_incoming_migration(f);
 107    qemu_set_fd_handler2(qemu_stdio_fd(f), NULL, NULL, NULL, NULL);
 108    qemu_fclose(f);
 109}
 110
 111int fd_start_incoming_migration(const char *infd)
 112{
 113    int fd;
 114    QEMUFile *f;
 115
 116    DPRINTF("Attempting to start an incoming migration via fd\n");
 117
 118    fd = strtol(infd, NULL, 0);
 119    f = qemu_fdopen(fd, "rb");
 120    if(f == NULL) {
 121        DPRINTF("Unable to apply qemu wrapper to file descriptor\n");
 122        return -errno;
 123    }
 124
 125    qemu_set_fd_handler2(fd, NULL, fd_accept_incoming_migration, NULL, f);
 126
 127    return 0;
 128}
 129