LXR qemu/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 */
  33void migration_channel_process_incoming(QIOChannel *ioc)
  34{
  35    MigrationState *s = migrate_get_current();
  36    MigrationIncomingState *mis = migration_incoming_get_current();
  37    Error *local_err = NULL;
  38
  39    trace_migration_set_incoming_channel(
  40        ioc, object_get_typename(OBJECT(ioc)));
  41
  42    if (migrate_channel_requires_tls_upgrade(ioc)) {
  43        migration_tls_channel_process_incoming(s, ioc, &local_err);
  44    } else {
  45        migration_ioc_register_yank(ioc);
  46        migration_ioc_process_incoming(ioc, &local_err);
  47    }
  48
  49    if (local_err) {
  50        error_report_err(local_err);
  51        migrate_set_state(&s->state, s->state, MIGRATION_STATUS_FAILED);
  52        if (mis->exit_on_error) {
  53            exit(EXIT_FAILURE);
  54        }
  55    }
  56}
  57
  58
  59/**
  60 * @migration_channel_connect - Create new outgoing migration channel
  61 *
  62 * @s: Current migration state
  63 * @ioc: Channel to which we are connecting
  64 * @hostname: Where we want to connect
  65 * @error: Error indicating failure to connect, free'd here
  66 */
  67void migration_channel_connect(MigrationState *s,
  68                               QIOChannel *ioc,
  69                               const char *hostname,
  70                               Error *error)
  71{
  72    trace_migration_set_outgoing_channel(
  73        ioc, object_get_typename(OBJECT(ioc)), hostname, error);
  74
  75    if (!error) {
  76        if (migrate_channel_requires_tls_upgrade(ioc)) {
  77            migration_tls_channel_connect(s, ioc, hostname, &error);
  78
  79            if (!error) {
  80                /* tls_channel_connect will call back to this
  81                 * function after the TLS handshake,
  82                 * so we mustn't call migration_connect until then
  83                 */
  84
  85                return;
  86            }
  87        } else {
  88            QEMUFile *f = qemu_file_new_output(ioc);
  89
  90            migration_ioc_register_yank(ioc);
  91
  92            qemu_mutex_lock(&s->qemu_file_lock);
  93            s->to_dst_file = f;
  94            qemu_mutex_unlock(&s->qemu_file_lock);
  95        }
  96    }
  97    migration_connect(s, error);
  98    error_free(error);
  99}
 100
 101
 102/**
 103 * @migration_channel_read_peek - Peek at migration channel, without
 104 *     actually removing it from channel buffer.
 105 *
 106 * @ioc: the channel object
 107 * @buf: the memory region to read data into
 108 * @buflen: the number of bytes to read in @buf
 109 * @errp: pointer to a NULL-initialized error object
 110 *
 111 * Returns 0 if successful, returns -1 and sets @errp if fails.
 112 */
 113int migration_channel_read_peek(QIOChannel *ioc,
 114                                const char *buf,
 115                                const size_t buflen,
 116                                Error **errp)
 117{
 118    ssize_t len = 0;
 119    struct iovec iov = { .iov_base = (char *)buf, .iov_len = buflen };
 120
 121    while (true) {
 122        len = qio_channel_readv_full(ioc, &iov, 1, NULL, NULL,
 123                                     QIO_CHANNEL_READ_FLAG_MSG_PEEK, errp);
 124
 125        if (len < 0 && len != QIO_CHANNEL_ERR_BLOCK) {
 126            return -1;
 127        }
 128
 129        if (len == 0) {
 130            error_setg(errp, "Failed to peek at channel");
 131            return -1;
 132        }
 133
 134        if (len == buflen) {
 135            break;
 136        }
 137
 138        /* 1ms sleep. */
 139        if (qemu_in_coroutine()) {
 140            qemu_co_sleep_ns(QEMU_CLOCK_REALTIME, 1000000);
 141        } else {
 142            g_usleep(1000);
 143        }
 144    }
 145
 146    return 0;
 147}
 148