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/osdep.h"
  17 #include "qapi/error.h"
  18 #include "qemu-common.h"
  19 #include "qemu/main-loop.h"
  20 #include "qemu/sockets.h"
  21 #include "migration/migration.h"
  22 #include "monitor/monitor.h"
  23 #include "migration/qemu-file.h"
  24 #include "block/block.h"
  25
  26 //#define DEBUG_MIGRATION_FD
  27
  28 #ifdef DEBUG_MIGRATION_FD
  29 #define DPRINTF(fmt, ...) \
  30     do { printf("migration-fd: " fmt, ## __VA_ARGS__); } while (0)
  31 #else
  32 #define DPRINTF(fmt, ...) \
  33     do { } while (0)
  34 #endif
  35
  36 static bool fd_is_socket(int fd)
  37 {
  38     struct stat stat;
  39     int ret = fstat(fd, &stat);
  40     if (ret == -1) {
  41         /* When in doubt say no */
  42         return false;
  43     }
  44     return S_ISSOCK(stat.st_mode);
  45 }
  46
  47 void fd_start_outgoing_migration(MigrationState *s, const char *fdname, Error **errp)
  48 {
  49     int fd = monitor_get_fd(cur_mon, fdname, errp);
  50     if (fd == -1) {
  51         return;
  52     }
  53
  54     if (fd_is_socket(fd)) {
  55         s->to_dst_file = qemu_fopen_socket(fd, "wb");
  56     } else {
  57         s->to_dst_file = qemu_fdopen(fd, "wb");
  58     }
  59
  60     migrate_fd_connect(s);
  61 }
  62
  63 static void fd_accept_incoming_migration(void *opaque)
  64 {
  65     QEMUFile *f = opaque;
  66
  67     qemu_set_fd_handler(qemu_get_fd(f), NULL, NULL, NULL);
  68     process_incoming_migration(f);
  69 }
  70
  71 void fd_start_incoming_migration(const char *infd, Error **errp)
  72 {
  73     int fd;
  74     QEMUFile *f;
  75
  76     DPRINTF("Attempting to start an incoming migration via fd\n");
  77
  78     fd = strtol(infd, NULL, 0);
  79     if (fd_is_socket(fd)) {
  80         f = qemu_fopen_socket(fd, "rb");
  81     } else {
  82         f = qemu_fdopen(fd, "rb");
  83     }
  84     if(f == NULL) {
  85         error_setg_errno(errp, errno, "failed to open the source descriptor");
  86         return;
  87     }
  88
  89     qemu_set_fd_handler(fd, fd_accept_incoming_migration, NULL, f);
  90 }