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