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