migration/channel.c

   1 /*
   2  * QEMU live migration channel operations
   3  *
   4  * Copyright Red Hat, Inc. 2016
   5  *
   6  * Authors:
   7  *  Daniel P. Berrange <berrange@redhat.com>
   8  *
   9  * Contributions after 2012-01-13 are licensed under the terms of the
  10  * GNU GPL, version 2 or (at your option) any later version.
  11  */
  12
  13 #include "qemu/osdep.h"
  14 #include "channel.h"
  15 #include "tls.h"
  16 #include "migration.h"
  17 #include "qemu-file.h"
  18 #include "trace.h"
  19 #include "qapi/error.h"
  20 #include "io/channel-tls.h"
  21 #include "io/channel-socket.h"
  22 #include "qemu/yank.h"
  23 #include "yank_functions.h"
  24
  25 /**
  26  * @migration_channel_process_incoming - Create new incoming migration channel
  27  *
  28  * Notice that TLS is special.  For it we listen in a listener socket,
  29  * and then create a new client socket from the TLS library.
  30  *
  31  * @ioc: Channel to which we are connecting
  32  */
  33 void migration_channel_process_incoming(QIOChannel *ioc)
  34 {
  35     MigrationState *s = migrate_get_current();
  36     Error *local_err = NULL;
  37
  38     trace_migration_set_incoming_channel(
  39         ioc, object_get_typename(OBJECT(ioc)));
  40
  41     if (migrate_channel_requires_tls_upgrade(ioc)) {
  42         migration_tls_channel_process_incoming(s, ioc, &local_err);
  43     } else {
  44         migration_ioc_register_yank(ioc);
  45         migration_ioc_process_incoming(ioc, &local_err);
  46     }
  47
  48     if (local_err) {
  49         error_report_err(local_err);
  50     }
  51 }
  52
  53
  54 /**
  55  * @migration_channel_connect - Create new outgoing migration channel
  56  *
  57  * @s: Current migration state
  58  * @ioc: Channel to which we are connecting
  59  * @hostname: Where we want to connect
  60  * @error: Error indicating failure to connect, free'd here
  61  */
  62 void migration_channel_connect(MigrationState *s,
  63                                QIOChannel *ioc,
  64                                const char *hostname,
  65                                Error *error)
  66 {
  67     trace_migration_set_outgoing_channel(
  68         ioc, object_get_typename(OBJECT(ioc)), hostname, error);
  69
  70     if (!error) {
  71         if (migrate_channel_requires_tls_upgrade(ioc)) {
  72             migration_tls_channel_connect(s, ioc, hostname, &error);
  73
  74             if (!error) {
  75                 /* tls_channel_connect will call back to this
  76                  * function after the TLS handshake,
  77                  * so we mustn't call migrate_fd_connect until then
  78                  */
  79
  80                 return;
  81             }
  82         } else {
  83             QEMUFile *f = qemu_file_new_output(ioc);
  84
  85             migration_ioc_register_yank(ioc);
  86
  87             qemu_mutex_lock(&s->qemu_file_lock);
  88             s->to_dst_file = f;
  89             qemu_mutex_unlock(&s->qemu_file_lock);
  90         }
  91     }
  92     migrate_fd_connect(s, error);
  93     error_free(error);
  94 }
  95
  96
  97 /**
  98  * @migration_channel_read_peek - Peek at migration channel, without
  99  *     actually removing it from channel buffer.
 100  *
 101  * @ioc: the channel object
 102  * @buf: the memory region to read data into
 103  * @buflen: the number of bytes to read in @buf
 104  * @errp: pointer to a NULL-initialized error object
 105  *
 106  * Returns 0 if successful, returns -1 and sets @errp if fails.
 107  */
 108 int migration_channel_read_peek(QIOChannel *ioc,
 109                                 const char *buf,
 110                                 const size_t buflen,
 111                                 Error **errp)
 112 {
 113     ssize_t len = 0;
 114     struct iovec iov = { .iov_base = (char *)buf, .iov_len = buflen };
 115
 116     while (true) {
 117         len = qio_channel_readv_full(ioc, &iov, 1, NULL, NULL,
 118                                      QIO_CHANNEL_READ_FLAG_MSG_PEEK, errp);
 119
 120         if (len < 0 && len != QIO_CHANNEL_ERR_BLOCK) {
 121             return -1;
 122         }
 123
 124         if (len == 0) {
 125             error_setg(errp, "Failed to peek at channel");
 126             return -1;
 127         }
 128
 129         if (len == buflen) {
 130             break;
 131         }
 132
 133         /* 1ms sleep. */
 134         if (qemu_in_coroutine()) {
 135             qemu_co_sleep_ns(QEMU_CLOCK_REALTIME, 1000000);
 136         } else {
 137             g_usleep(1000);
 138         }
 139     }
 140
 141     return 0;
 142 }