xref: /openbmc/qemu/util/qemu-sockets.c (revision a8d25326)

/*
 *  inet and unix socket functions for qemu
 *
 *  (c) 2008 Gerd Hoffmann <kraxel@redhat.com>
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; under version 2 of the License.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 * Contributions after 2012-01-13 are licensed under the terms of the
 * GNU GPL, version 2 or (at your option) any later version.
 */
#include "qemu/osdep.h"

#ifdef CONFIG_AF_VSOCK
#include <linux/vm_sockets.h>
#endif /* CONFIG_AF_VSOCK */

#include "qemu-common.h"
#include "monitor/monitor.h"
#include "qapi/clone-visitor.h"
#include "qapi/error.h"
#include "qapi/qapi-visit-sockets.h"
#include "qemu/sockets.h"
#include "qemu/main-loop.h"
#include "qapi/qobject-input-visitor.h"
#include "qapi/qobject-output-visitor.h"
#include "qemu/cutils.h"

#ifndef AI_ADDRCONFIG
# define AI_ADDRCONFIG 0
#endif

#ifndef AI_V4MAPPED
# define AI_V4MAPPED 0
#endif

#ifndef AI_NUMERICSERV
# define AI_NUMERICSERV 0
#endif


static int inet_getport(struct addrinfo *e)
{
    struct sockaddr_in *i4;
    struct sockaddr_in6 *i6;

    switch (e->ai_family) {
    case PF_INET6:
        i6 = (void*)e->ai_addr;
        return ntohs(i6->sin6_port);
    case PF_INET:
        i4 = (void*)e->ai_addr;
        return ntohs(i4->sin_port);
    default:
        return 0;
    }
}

static void inet_setport(struct addrinfo *e, int port)
{
    struct sockaddr_in *i4;
    struct sockaddr_in6 *i6;

    switch (e->ai_family) {
    case PF_INET6:
        i6 = (void*)e->ai_addr;
        i6->sin6_port = htons(port);
        break;
    case PF_INET:
        i4 = (void*)e->ai_addr;
        i4->sin_port = htons(port);
        break;
    }
}

NetworkAddressFamily inet_netfamily(int family)
{
    switch (family) {
    case PF_INET6: return NETWORK_ADDRESS_FAMILY_IPV6;
    case PF_INET:  return NETWORK_ADDRESS_FAMILY_IPV4;
    case PF_UNIX:  return NETWORK_ADDRESS_FAMILY_UNIX;
#ifdef CONFIG_AF_VSOCK
    case PF_VSOCK: return NETWORK_ADDRESS_FAMILY_VSOCK;
#endif /* CONFIG_AF_VSOCK */
    }
    return NETWORK_ADDRESS_FAMILY_UNKNOWN;
}

bool fd_is_socket(int fd)
{
    int optval;
    socklen_t optlen = sizeof(optval);
    return !qemu_getsockopt(fd, SOL_SOCKET, SO_TYPE, &optval, &optlen);
}


/*
 * Matrix we're trying to apply
 *
 *  ipv4  ipv6   family
 *   -     -       PF_UNSPEC
 *   -     f       PF_INET
 *   -     t       PF_INET6
 *   f     -       PF_INET6
 *   f     f       <error>
 *   f     t       PF_INET6
 *   t     -       PF_INET
 *   t     f       PF_INET
 *   t     t       PF_INET6/PF_UNSPEC
 *
 * NB, this matrix is only about getting the necessary results
 * from getaddrinfo(). Some of the cases require further work
 * after reading results from getaddrinfo in order to fully
 * apply the logic the end user wants.
 *
 * In the first and last cases, we must set IPV6_V6ONLY=0
 * when binding, to allow a single listener to potentially
 * accept both IPv4+6 addresses.
 */
int inet_ai_family_from_address(InetSocketAddress *addr,
                                Error **errp)
{
    if (addr->has_ipv6 && addr->has_ipv4 &&
        !addr->ipv6 && !addr->ipv4) {
        error_setg(errp, "Cannot disable IPv4 and IPv6 at same time");
        return PF_UNSPEC;
    }
    if ((addr->has_ipv6 && addr->ipv6) && (addr->has_ipv4 && addr->ipv4)) {
        /*
         * Some backends can only do a single listener. In that case
         * we want empty hostname to resolve to "::" and then use the
         * flag IPV6_V6ONLY==0 to get both protocols on 1 socket. This
         * doesn't work for addresses other than "", so they're just
         * inevitably broken until multiple listeners can be used,
         * and thus we honour getaddrinfo automatic protocol detection
         * Once all backends do multi-listener, remove the PF_INET6
         * branch entirely.
         */
        if (!addr->host || g_str_equal(addr->host, "")) {
            return PF_INET6;
        } else {
            return PF_UNSPEC;
        }
    }
    if ((addr->has_ipv6 && addr->ipv6) || (addr->has_ipv4 && !addr->ipv4)) {
        return PF_INET6;
    }
    if ((addr->has_ipv4 && addr->ipv4) || (addr->has_ipv6 && !addr->ipv6)) {
        return PF_INET;
    }
    return PF_UNSPEC;
}

static int create_fast_reuse_socket(struct addrinfo *e)
{
    int slisten = qemu_socket(e->ai_family, e->ai_socktype, e->ai_protocol);
    if (slisten < 0) {
        return -1;
    }
    socket_set_fast_reuse(slisten);
    return slisten;
}

static int try_bind(int socket, InetSocketAddress *saddr, struct addrinfo *e)
{
#ifndef IPV6_V6ONLY
    return bind(socket, e->ai_addr, e->ai_addrlen);
#else
    /*
     * Deals with first & last cases in matrix in comment
     * for inet_ai_family_from_address().
     */
    int v6only =
        ((!saddr->has_ipv4 && !saddr->has_ipv6) ||
         (saddr->has_ipv4 && saddr->ipv4 &&
          saddr->has_ipv6 && saddr->ipv6)) ? 0 : 1;
    int stat;

 rebind:
    if (e->ai_family == PF_INET6) {
        qemu_setsockopt(socket, IPPROTO_IPV6, IPV6_V6ONLY, &v6only,
                        sizeof(v6only));
    }

    stat = bind(socket, e->ai_addr, e->ai_addrlen);
    if (!stat) {
        return 0;
    }

    /* If we got EADDRINUSE from an IPv6 bind & v6only is unset,
     * it could be that the IPv4 port is already claimed, so retry
     * with v6only set
     */
    if (e->ai_family == PF_INET6 && errno == EADDRINUSE && !v6only) {
        v6only = 1;
        goto rebind;
    }
    return stat;
#endif
}

static int inet_listen_saddr(InetSocketAddress *saddr,
                             int port_offset,
                             Error **errp)
{
    struct addrinfo ai,*res,*e;
    char port[33];
    char uaddr[INET6_ADDRSTRLEN+1];
    char uport[33];
    int rc, port_min, port_max, p;
    int slisten = -1;
    int saved_errno = 0;
    bool socket_created = false;
    Error *err = NULL;

    memset(&ai,0, sizeof(ai));
    ai.ai_flags = AI_PASSIVE;
    if (saddr->has_numeric && saddr->numeric) {
        ai.ai_flags |= AI_NUMERICHOST | AI_NUMERICSERV;
    }
    ai.ai_family = inet_ai_family_from_address(saddr, &err);
    ai.ai_socktype = SOCK_STREAM;

    if (err) {
        error_propagate(errp, err);
        return -1;
    }

    if (saddr->host == NULL) {
        error_setg(errp, "host not specified");
        return -1;
    }
    if (saddr->port != NULL) {
        pstrcpy(port, sizeof(port), saddr->port);
    } else {
        port[0] = '\0';
    }

    /* lookup */
    if (port_offset) {
        unsigned long long baseport;
        if (strlen(port) == 0) {
            error_setg(errp, "port not specified");
            return -1;
        }
        if (parse_uint_full(port, &baseport, 10) < 0) {
            error_setg(errp, "can't convert to a number: %s", port);
            return -1;
        }
        if (baseport > 65535 ||
            baseport + port_offset > 65535) {
            error_setg(errp, "port %s out of range", port);
            return -1;
        }
        snprintf(port, sizeof(port), "%d", (int)baseport + port_offset);
    }
    rc = getaddrinfo(strlen(saddr->host) ? saddr->host : NULL,
                     strlen(port) ? port : NULL, &ai, &res);
    if (rc != 0) {
        error_setg(errp, "address resolution failed for %s:%s: %s",
                   saddr->host, port, gai_strerror(rc));
        return -1;
    }

    /* create socket + bind/listen */
    for (e = res; e != NULL; e = e->ai_next) {
        getnameinfo((struct sockaddr*)e->ai_addr,e->ai_addrlen,
                        uaddr,INET6_ADDRSTRLEN,uport,32,
                        NI_NUMERICHOST | NI_NUMERICSERV);

        port_min = inet_getport(e);
        port_max = saddr->has_to ? saddr->to + port_offset : port_min;
        for (p = port_min; p <= port_max; p++) {
            inet_setport(e, p);

            slisten = create_fast_reuse_socket(e);
            if (slisten < 0) {
                /* First time we expect we might fail to create the socket
                 * eg if 'e' has AF_INET6 but ipv6 kmod is not loaded.
                 * Later iterations should always succeed if first iteration
                 * worked though, so treat that as fatal.
                 */
                if (p == port_min) {
                    continue;
                } else {
                    error_setg_errno(errp, errno,
                                     "Failed to recreate failed listening socket");
                    goto listen_failed;
                }
            }
            socket_created = true;

            rc = try_bind(slisten, saddr, e);
            if (rc < 0) {
                if (errno != EADDRINUSE) {
                    error_setg_errno(errp, errno, "Failed to bind socket");
                    goto listen_failed;
                }
            } else {
                if (!listen(slisten, 1)) {
                    goto listen_ok;
                }
                if (errno != EADDRINUSE) {
                    error_setg_errno(errp, errno, "Failed to listen on socket");
                    goto listen_failed;
                }
            }
            /* Someone else managed to bind to the same port and beat us
             * to listen on it! Socket semantics does not allow us to
             * recover from this situation, so we need to recreate the
             * socket to allow bind attempts for subsequent ports:
             */
            closesocket(slisten);
            slisten = -1;
        }
    }
    error_setg_errno(errp, errno,
                     socket_created ?
                     "Failed to find an available port" :
                     "Failed to create a socket");
listen_failed:
    saved_errno = errno;
    if (slisten >= 0) {
        closesocket(slisten);
    }
    freeaddrinfo(res);
    errno = saved_errno;
    return -1;

listen_ok:
    freeaddrinfo(res);
    return slisten;
}

#ifdef _WIN32
#define QEMU_SOCKET_RC_INPROGRESS(rc) \
    ((rc) == -EINPROGRESS || (rc) == -EWOULDBLOCK || (rc) == -WSAEALREADY)
#else
#define QEMU_SOCKET_RC_INPROGRESS(rc) \
    ((rc) == -EINPROGRESS)
#endif

static int inet_connect_addr(struct addrinfo *addr, Error **errp);

static int inet_connect_addr(struct addrinfo *addr, Error **errp)
{
    int sock, rc;

    sock = qemu_socket(addr->ai_family, addr->ai_socktype, addr->ai_protocol);
    if (sock < 0) {
        error_setg_errno(errp, errno, "Failed to create socket");
        return -1;
    }
    socket_set_fast_reuse(sock);

    /* connect to peer */
    do {
        rc = 0;
        if (connect(sock, addr->ai_addr, addr->ai_addrlen) < 0) {
            rc = -errno;
        }
    } while (rc == -EINTR);

    if (rc < 0) {
        error_setg_errno(errp, errno, "Failed to connect socket");
        closesocket(sock);
        return -1;
    }

    return sock;
}

static struct addrinfo *inet_parse_connect_saddr(InetSocketAddress *saddr,
                                                 Error **errp)
{
    struct addrinfo ai, *res;
    int rc;
    Error *err = NULL;
    static int useV4Mapped = 1;

    memset(&ai, 0, sizeof(ai));

    ai.ai_flags = AI_CANONNAME | AI_ADDRCONFIG;
    if (atomic_read(&useV4Mapped)) {
        ai.ai_flags |= AI_V4MAPPED;
    }
    ai.ai_family = inet_ai_family_from_address(saddr, &err);
    ai.ai_socktype = SOCK_STREAM;

    if (err) {
        error_propagate(errp, err);
        return NULL;
    }

    if (saddr->host == NULL || saddr->port == NULL) {
        error_setg(errp, "host and/or port not specified");
        return NULL;
    }

    /* lookup */
    rc = getaddrinfo(saddr->host, saddr->port, &ai, &res);

    /* At least FreeBSD and OS-X 10.6 declare AI_V4MAPPED but
     * then don't implement it in their getaddrinfo(). Detect
     * this and retry without the flag since that's preferrable
     * to a fatal error
     */
    if (rc == EAI_BADFLAGS &&
        (ai.ai_flags & AI_V4MAPPED)) {
        atomic_set(&useV4Mapped, 0);
        ai.ai_flags &= ~AI_V4MAPPED;
        rc = getaddrinfo(saddr->host, saddr->port, &ai, &res);
    }
    if (rc != 0) {
        error_setg(errp, "address resolution failed for %s:%s: %s",
                   saddr->host, saddr->port, gai_strerror(rc));
        return NULL;
    }
    return res;
}

/**
 * Create a socket and connect it to an address.
 *
 * @saddr: Inet socket address specification
 * @errp: set on error
 *
 * Returns: -1 on error, file descriptor on success.
 */
int inet_connect_saddr(InetSocketAddress *saddr, Error **errp)
{
    Error *local_err = NULL;
    struct addrinfo *res, *e;
    int sock = -1;

    res = inet_parse_connect_saddr(saddr, errp);
    if (!res) {
        return -1;
    }

    for (e = res; e != NULL; e = e->ai_next) {
        error_free(local_err);
        local_err = NULL;
        sock = inet_connect_addr(e, &local_err);
        if (sock >= 0) {
            break;
        }
    }

    if (sock < 0) {
        error_propagate(errp, local_err);
    }

    freeaddrinfo(res);
    return sock;
}

static int inet_dgram_saddr(InetSocketAddress *sraddr,
                            InetSocketAddress *sladdr,
                            Error **errp)
{
    struct addrinfo ai, *peer = NULL, *local = NULL;
    const char *addr;
    const char *port;
    int sock = -1, rc;
    Error *err = NULL;

    /* lookup peer addr */
    memset(&ai,0, sizeof(ai));
    ai.ai_flags = AI_CANONNAME | AI_V4MAPPED | AI_ADDRCONFIG;
    ai.ai_family = inet_ai_family_from_address(sraddr, &err);
    ai.ai_socktype = SOCK_DGRAM;

    if (err) {
        error_propagate(errp, err);
        goto err;
    }

    addr = sraddr->host;
    port = sraddr->port;
    if (addr == NULL || strlen(addr) == 0) {
        addr = "localhost";
    }
    if (port == NULL || strlen(port) == 0) {
        error_setg(errp, "remote port not specified");
        goto err;
    }

    if ((rc = getaddrinfo(addr, port, &ai, &peer)) != 0) {
        error_setg(errp, "address resolution failed for %s:%s: %s", addr, port,
                   gai_strerror(rc));
        goto err;
    }

    /* lookup local addr */
    memset(&ai,0, sizeof(ai));
    ai.ai_flags = AI_PASSIVE;
    ai.ai_family = peer->ai_family;
    ai.ai_socktype = SOCK_DGRAM;

    if (sladdr) {
        addr = sladdr->host;
        port = sladdr->port;
        if (addr == NULL || strlen(addr) == 0) {
            addr = NULL;
        }
        if (!port || strlen(port) == 0) {
            port = "0";
        }
    } else {
        addr = NULL;
        port = "0";
    }

    if ((rc = getaddrinfo(addr, port, &ai, &local)) != 0) {
        error_setg(errp, "address resolution failed for %s:%s: %s", addr, port,
                   gai_strerror(rc));
        goto err;
    }

    /* create socket */
    sock = qemu_socket(peer->ai_family, peer->ai_socktype, peer->ai_protocol);
    if (sock < 0) {
        error_setg_errno(errp, errno, "Failed to create socket");
        goto err;
    }
    socket_set_fast_reuse(sock);

    /* bind socket */
    if (bind(sock, local->ai_addr, local->ai_addrlen) < 0) {
        error_setg_errno(errp, errno, "Failed to bind socket");
        goto err;
    }

    /* connect to peer */
    if (connect(sock,peer->ai_addr,peer->ai_addrlen) < 0) {
        error_setg_errno(errp, errno, "Failed to connect socket");
        goto err;
    }

    freeaddrinfo(local);
    freeaddrinfo(peer);
    return sock;

err:
    if (sock != -1) {
        closesocket(sock);
    }
    if (local) {
        freeaddrinfo(local);
    }
    if (peer) {
        freeaddrinfo(peer);
    }

    return -1;
}

/* compatibility wrapper */
static int inet_parse_flag(const char *flagname, const char *optstr, bool *val,
                           Error **errp)
{
    char *end;
    size_t len;

    end = strstr(optstr, ",");
    if (end) {
        if (end[1] == ',') { /* Reject 'ipv6=on,,foo' */
            error_setg(errp, "error parsing '%s' flag '%s'", flagname, optstr);
            return -1;
        }
        len = end - optstr;
    } else {
        len = strlen(optstr);
    }
    if (len == 0 || (len == 3 && strncmp(optstr, "=on", len) == 0)) {
        *val = true;
    } else if (len == 4 && strncmp(optstr, "=off", len) == 0) {
        *val = false;
    } else {
        error_setg(errp, "error parsing '%s' flag '%s'", flagname, optstr);
        return -1;
    }
    return 0;
}

int inet_parse(InetSocketAddress *addr, const char *str, Error **errp)
{
    const char *optstr, *h;
    char host[65];
    char port[33];
    int to;
    int pos;
    char *begin;

    memset(addr, 0, sizeof(*addr));

    /* parse address */
    if (str[0] == ':') {
        /* no host given */
        host[0] = '\0';
        if (sscanf(str, ":%32[^,]%n", port, &pos) != 1) {
            error_setg(errp, "error parsing port in address '%s'", str);
            return -1;
        }
    } else if (str[0] == '[') {
        /* IPv6 addr */
        if (sscanf(str, "[%64[^]]]:%32[^,]%n", host, port, &pos) != 2) {
            error_setg(errp, "error parsing IPv6 address '%s'", str);
            return -1;
        }
    } else {
        /* hostname or IPv4 addr */
        if (sscanf(str, "%64[^:]:%32[^,]%n", host, port, &pos) != 2) {
            error_setg(errp, "error parsing address '%s'", str);
            return -1;
        }
    }

    addr->host = g_strdup(host);
    addr->port = g_strdup(port);

    /* parse options */
    optstr = str + pos;
    h = strstr(optstr, ",to=");
    if (h) {
        h += 4;
        if (sscanf(h, "%d%n", &to, &pos) != 1 ||
            (h[pos] != '\0' && h[pos] != ',')) {
            error_setg(errp, "error parsing to= argument");
            return -1;
        }
        addr->has_to = true;
        addr->to = to;
    }
    begin = strstr(optstr, ",ipv4");
    if (begin) {
        if (inet_parse_flag("ipv4", begin + 5, &addr->ipv4, errp) < 0) {
            return -1;
        }
        addr->has_ipv4 = true;
    }
    begin = strstr(optstr, ",ipv6");
    if (begin) {
        if (inet_parse_flag("ipv6", begin + 5, &addr->ipv6, errp) < 0) {
            return -1;
        }
        addr->has_ipv6 = true;
    }
    return 0;
}


/**
 * Create a blocking socket and connect it to an address.
 *
 * @str: address string
 * @errp: set in case of an error
 *
 * Returns -1 in case of error, file descriptor on success
 **/
int inet_connect(const char *str, Error **errp)
{
    int sock = -1;
    InetSocketAddress *addr = g_new(InetSocketAddress, 1);

    if (!inet_parse(addr, str, errp)) {
        sock = inet_connect_saddr(addr, errp);
    }
    qapi_free_InetSocketAddress(addr);
    return sock;
}

#ifdef CONFIG_AF_VSOCK
static bool vsock_parse_vaddr_to_sockaddr(const VsockSocketAddress *vaddr,
                                          struct sockaddr_vm *svm,
                                          Error **errp)
{
    unsigned long long val;

    memset(svm, 0, sizeof(*svm));
    svm->svm_family = AF_VSOCK;

    if (parse_uint_full(vaddr->cid, &val, 10) < 0 ||
        val > UINT32_MAX) {
        error_setg(errp, "Failed to parse cid '%s'", vaddr->cid);
        return false;
    }
    svm->svm_cid = val;

    if (parse_uint_full(vaddr->port, &val, 10) < 0 ||
        val > UINT32_MAX) {
        error_setg(errp, "Failed to parse port '%s'", vaddr->port);
        return false;
    }
    svm->svm_port = val;

    return true;
}

static int vsock_connect_addr(const struct sockaddr_vm *svm, Error **errp)
{
    int sock, rc;

    sock = qemu_socket(AF_VSOCK, SOCK_STREAM, 0);
    if (sock < 0) {
        error_setg_errno(errp, errno, "Failed to create socket");
        return -1;
    }

    /* connect to peer */
    do {
        rc = 0;
        if (connect(sock, (const struct sockaddr *)svm, sizeof(*svm)) < 0) {
            rc = -errno;
        }
    } while (rc == -EINTR);

    if (rc < 0) {
        error_setg_errno(errp, errno, "Failed to connect socket");
        closesocket(sock);
        return -1;
    }

    return sock;
}

static int vsock_connect_saddr(VsockSocketAddress *vaddr, Error **errp)
{
    struct sockaddr_vm svm;
    int sock = -1;

    if (!vsock_parse_vaddr_to_sockaddr(vaddr, &svm, errp)) {
        return -1;
    }

    sock = vsock_connect_addr(&svm, errp);

    return sock;
}

static int vsock_listen_saddr(VsockSocketAddress *vaddr,
                              Error **errp)
{
    struct sockaddr_vm svm;
    int slisten;

    if (!vsock_parse_vaddr_to_sockaddr(vaddr, &svm, errp)) {
        return -1;
    }

    slisten = qemu_socket(AF_VSOCK, SOCK_STREAM, 0);
    if (slisten < 0) {
        error_setg_errno(errp, errno, "Failed to create socket");
        return -1;
    }

    if (bind(slisten, (const struct sockaddr *)&svm, sizeof(svm)) != 0) {
        error_setg_errno(errp, errno, "Failed to bind socket");
        closesocket(slisten);
        return -1;
    }

    if (listen(slisten, 1) != 0) {
        error_setg_errno(errp, errno, "Failed to listen on socket");
        closesocket(slisten);
        return -1;
    }
    return slisten;
}

static int vsock_parse(VsockSocketAddress *addr, const char *str,
                       Error **errp)
{
    char cid[33];
    char port[33];
    int n;

    if (sscanf(str, "%32[^:]:%32[^,]%n", cid, port, &n) != 2) {
        error_setg(errp, "error parsing address '%s'", str);
        return -1;
    }
    if (str[n] != '\0') {
        error_setg(errp, "trailing characters in address '%s'", str);
        return -1;
    }

    addr->cid = g_strdup(cid);
    addr->port = g_strdup(port);
    return 0;
}
#else
static void vsock_unsupported(Error **errp)
{
    error_setg(errp, "socket family AF_VSOCK unsupported");
}

static int vsock_connect_saddr(VsockSocketAddress *vaddr, Error **errp)
{
    vsock_unsupported(errp);
    return -1;
}

static int vsock_listen_saddr(VsockSocketAddress *vaddr,
                              Error **errp)
{
    vsock_unsupported(errp);
    return -1;
}

static int vsock_parse(VsockSocketAddress *addr, const char *str,
                        Error **errp)
{
    vsock_unsupported(errp);
    return -1;
}
#endif /* CONFIG_AF_VSOCK */

#ifndef _WIN32

static int unix_listen_saddr(UnixSocketAddress *saddr,
                             Error **errp)
{
    struct sockaddr_un un;
    int sock, fd;
    char *pathbuf = NULL;
    const char *path;
    size_t pathlen;

    sock = qemu_socket(PF_UNIX, SOCK_STREAM, 0);
    if (sock < 0) {
        error_setg_errno(errp, errno, "Failed to create Unix socket");
        return -1;
    }

    if (saddr->path && saddr->path[0]) {
        path = saddr->path;
    } else {
        const char *tmpdir = getenv("TMPDIR");
        tmpdir = tmpdir ? tmpdir : "/tmp";
        path = pathbuf = g_strdup_printf("%s/qemu-socket-XXXXXX", tmpdir);
    }

    pathlen = strlen(path);
    if (pathlen > sizeof(un.sun_path)) {
        error_setg(errp, "UNIX socket path '%s' is too long", path);
        error_append_hint(errp, "Path must be less than %zu bytes\n",
                          sizeof(un.sun_path));
        goto err;
    }

    if (pathbuf != NULL) {
        /*
         * This dummy fd usage silences the mktemp() unsecure warning.
         * Using mkstemp() doesn't make things more secure here
         * though.  bind() complains about existing files, so we have
         * to unlink first and thus re-open the race window.  The
         * worst case possible is bind() failing, i.e. a DoS attack.
         */
        fd = mkstemp(pathbuf);
        if (fd < 0) {
            error_setg_errno(errp, errno,
                             "Failed to make a temporary socket %s", pathbuf);
            goto err;
        }
        close(fd);
    }

    if (unlink(path) < 0 && errno != ENOENT) {
        error_setg_errno(errp, errno,
                         "Failed to unlink socket %s", path);
        goto err;
    }

    memset(&un, 0, sizeof(un));
    un.sun_family = AF_UNIX;
    memcpy(un.sun_path, path, pathlen);

    if (bind(sock, (struct sockaddr*) &un, sizeof(un)) < 0) {
        error_setg_errno(errp, errno, "Failed to bind socket to %s", path);
        goto err;
    }
    if (listen(sock, 1) < 0) {
        error_setg_errno(errp, errno, "Failed to listen on socket");
        goto err;
    }

    g_free(pathbuf);
    return sock;

err:
    g_free(pathbuf);
    closesocket(sock);
    return -1;
}

static int unix_connect_saddr(UnixSocketAddress *saddr, Error **errp)
{
    struct sockaddr_un un;
    int sock, rc;
    size_t pathlen;

    if (saddr->path == NULL) {
        error_setg(errp, "unix connect: no path specified");
        return -1;
    }

    sock = qemu_socket(PF_UNIX, SOCK_STREAM, 0);
    if (sock < 0) {
        error_setg_errno(errp, errno, "Failed to create socket");
        return -1;
    }

    pathlen = strlen(saddr->path);
    if (pathlen > sizeof(un.sun_path)) {
        error_setg(errp, "UNIX socket path '%s' is too long", saddr->path);
        error_append_hint(errp, "Path must be less than %zu bytes\n",
                          sizeof(un.sun_path));
        goto err;
    }

    memset(&un, 0, sizeof(un));
    un.sun_family = AF_UNIX;
    memcpy(un.sun_path, saddr->path, pathlen);

    /* connect to peer */
    do {
        rc = 0;
        if (connect(sock, (struct sockaddr *) &un, sizeof(un)) < 0) {
            rc = -errno;
        }
    } while (rc == -EINTR);

    if (rc < 0) {
        error_setg_errno(errp, -rc, "Failed to connect socket %s",
                         saddr->path);
        goto err;
    }

    return sock;

 err:
    close(sock);
    return -1;
}

#else

static int unix_listen_saddr(UnixSocketAddress *saddr,
                             Error **errp)
{
    error_setg(errp, "unix sockets are not available on windows");
    errno = ENOTSUP;
    return -1;
}

static int unix_connect_saddr(UnixSocketAddress *saddr, Error **errp)
{
    error_setg(errp, "unix sockets are not available on windows");
    errno = ENOTSUP;
    return -1;
}
#endif

/* compatibility wrapper */
int unix_listen(const char *str, Error **errp)
{
    UnixSocketAddress *saddr;
    int sock;

    saddr = g_new0(UnixSocketAddress, 1);
    saddr->path = g_strdup(str);
    sock = unix_listen_saddr(saddr, errp);
    qapi_free_UnixSocketAddress(saddr);
    return sock;
}

int unix_connect(const char *path, Error **errp)
{
    UnixSocketAddress *saddr;
    int sock;

    saddr = g_new0(UnixSocketAddress, 1);
    saddr->path = g_strdup(path);
    sock = unix_connect_saddr(saddr, errp);
    qapi_free_UnixSocketAddress(saddr);
    return sock;
}


SocketAddress *socket_parse(const char *str, Error **errp)
{
    SocketAddress *addr;

    addr = g_new0(SocketAddress, 1);
    if (strstart(str, "unix:", NULL)) {
        if (str[5] == '\0') {
            error_setg(errp, "invalid Unix socket address");
            goto fail;
        } else {
            addr->type = SOCKET_ADDRESS_TYPE_UNIX;
            addr->u.q_unix.path = g_strdup(str + 5);
        }
    } else if (strstart(str, "fd:", NULL)) {
        if (str[3] == '\0') {
            error_setg(errp, "invalid file descriptor address");
            goto fail;
        } else {
            addr->type = SOCKET_ADDRESS_TYPE_FD;
            addr->u.fd.str = g_strdup(str + 3);
        }
    } else if (strstart(str, "vsock:", NULL)) {
        addr->type = SOCKET_ADDRESS_TYPE_VSOCK;
        if (vsock_parse(&addr->u.vsock, str + strlen("vsock:"), errp)) {
            goto fail;
        }
    } else {
        addr->type = SOCKET_ADDRESS_TYPE_INET;
        if (inet_parse(&addr->u.inet, str, errp)) {
            goto fail;
        }
    }
    return addr;

fail:
    qapi_free_SocketAddress(addr);
    return NULL;
}

static int socket_get_fd(const char *fdstr, Error **errp)
{
    int fd;
    if (cur_mon) {
        fd = monitor_get_fd(cur_mon, fdstr, errp);
        if (fd < 0) {
            return -1;
        }
    } else {
        if (qemu_strtoi(fdstr, NULL, 10, &fd) < 0) {
            error_setg_errno(errp, errno,
                             "Unable to parse FD number %s",
                             fdstr);
            return -1;
        }
    }
    if (!fd_is_socket(fd)) {
        error_setg(errp, "File descriptor '%s' is not a socket", fdstr);
        close(fd);
        return -1;
    }
    return fd;
}

int socket_connect(SocketAddress *addr, Error **errp)
{
    int fd;

    switch (addr->type) {
    case SOCKET_ADDRESS_TYPE_INET:
        fd = inet_connect_saddr(&addr->u.inet, errp);
        break;

    case SOCKET_ADDRESS_TYPE_UNIX:
        fd = unix_connect_saddr(&addr->u.q_unix, errp);
        break;

    case SOCKET_ADDRESS_TYPE_FD:
        fd = socket_get_fd(addr->u.fd.str, errp);
        break;

    case SOCKET_ADDRESS_TYPE_VSOCK:
        fd = vsock_connect_saddr(&addr->u.vsock, errp);
        break;

    default:
        abort();
    }
    return fd;
}

int socket_listen(SocketAddress *addr, Error **errp)
{
    int fd;

    switch (addr->type) {
    case SOCKET_ADDRESS_TYPE_INET:
        fd = inet_listen_saddr(&addr->u.inet, 0, errp);
        break;

    case SOCKET_ADDRESS_TYPE_UNIX:
        fd = unix_listen_saddr(&addr->u.q_unix, errp);
        break;

    case SOCKET_ADDRESS_TYPE_FD:
        fd = socket_get_fd(addr->u.fd.str, errp);
        break;

    case SOCKET_ADDRESS_TYPE_VSOCK:
        fd = vsock_listen_saddr(&addr->u.vsock, errp);
        break;

    default:
        abort();
    }
    return fd;
}

void socket_listen_cleanup(int fd, Error **errp)
{
    SocketAddress *addr;

    addr = socket_local_address(fd, errp);
    if (!addr) {
        return;
    }

    if (addr->type == SOCKET_ADDRESS_TYPE_UNIX
        && addr->u.q_unix.path) {
        if (unlink(addr->u.q_unix.path) < 0 && errno != ENOENT) {
            error_setg_errno(errp, errno,
                             "Failed to unlink socket %s",
                             addr->u.q_unix.path);
        }
    }

    qapi_free_SocketAddress(addr);
}

int socket_dgram(SocketAddress *remote, SocketAddress *local, Error **errp)
{
    int fd;

    /*
     * TODO SOCKET_ADDRESS_TYPE_FD when fd is AF_INET or AF_INET6
     * (although other address families can do SOCK_DGRAM, too)
     */
    switch (remote->type) {
    case SOCKET_ADDRESS_TYPE_INET:
        fd = inet_dgram_saddr(&remote->u.inet,
                              local ? &local->u.inet : NULL, errp);
        break;

    default:
        error_setg(errp, "socket type unsupported for datagram");
        fd = -1;
    }
    return fd;
}


static SocketAddress *
socket_sockaddr_to_address_inet(struct sockaddr_storage *sa,
                                socklen_t salen,
                                Error **errp)
{
    char host[NI_MAXHOST];
    char serv[NI_MAXSERV];
    SocketAddress *addr;
    InetSocketAddress *inet;
    int ret;

    ret = getnameinfo((struct sockaddr *)sa, salen,
                      host, sizeof(host),
                      serv, sizeof(serv),
                      NI_NUMERICHOST | NI_NUMERICSERV);
    if (ret != 0) {
        error_setg(errp, "Cannot format numeric socket address: %s",
                   gai_strerror(ret));
        return NULL;
    }

    addr = g_new0(SocketAddress, 1);
    addr->type = SOCKET_ADDRESS_TYPE_INET;
    inet = &addr->u.inet;
    inet->host = g_strdup(host);
    inet->port = g_strdup(serv);
    if (sa->ss_family == AF_INET) {
        inet->has_ipv4 = inet->ipv4 = true;
    } else {
        inet->has_ipv6 = inet->ipv6 = true;
    }

    return addr;
}


#ifndef WIN32
static SocketAddress *
socket_sockaddr_to_address_unix(struct sockaddr_storage *sa,
                                socklen_t salen,
                                Error **errp)
{
    SocketAddress *addr;
    struct sockaddr_un *su = (struct sockaddr_un *)sa;

    addr = g_new0(SocketAddress, 1);
    addr->type = SOCKET_ADDRESS_TYPE_UNIX;
    if (su->sun_path[0]) {
        addr->u.q_unix.path = g_strndup(su->sun_path, sizeof(su->sun_path));
    }

    return addr;
}
#endif /* WIN32 */

#ifdef CONFIG_AF_VSOCK
static SocketAddress *
socket_sockaddr_to_address_vsock(struct sockaddr_storage *sa,
                                 socklen_t salen,
                                 Error **errp)
{
    SocketAddress *addr;
    VsockSocketAddress *vaddr;
    struct sockaddr_vm *svm = (struct sockaddr_vm *)sa;

    addr = g_new0(SocketAddress, 1);
    addr->type = SOCKET_ADDRESS_TYPE_VSOCK;
    vaddr = &addr->u.vsock;
    vaddr->cid = g_strdup_printf("%u", svm->svm_cid);
    vaddr->port = g_strdup_printf("%u", svm->svm_port);

    return addr;
}
#endif /* CONFIG_AF_VSOCK */

SocketAddress *
socket_sockaddr_to_address(struct sockaddr_storage *sa,
                           socklen_t salen,
                           Error **errp)
{
    switch (sa->ss_family) {
    case AF_INET:
    case AF_INET6:
        return socket_sockaddr_to_address_inet(sa, salen, errp);

#ifndef WIN32
    case AF_UNIX:
        return socket_sockaddr_to_address_unix(sa, salen, errp);
#endif /* WIN32 */

#ifdef CONFIG_AF_VSOCK
    case AF_VSOCK:
        return socket_sockaddr_to_address_vsock(sa, salen, errp);
#endif

    default:
        error_setg(errp, "socket family %d unsupported",
                   sa->ss_family);
        return NULL;
    }
    return 0;
}


SocketAddress *socket_local_address(int fd, Error **errp)
{
    struct sockaddr_storage ss;
    socklen_t sslen = sizeof(ss);

    if (getsockname(fd, (struct sockaddr *)&ss, &sslen) < 0) {
        error_setg_errno(errp, errno, "%s",
                         "Unable to query local socket address");
        return NULL;
    }

    return socket_sockaddr_to_address(&ss, sslen, errp);
}


SocketAddress *socket_remote_address(int fd, Error **errp)
{
    struct sockaddr_storage ss;
    socklen_t sslen = sizeof(ss);

    if (getpeername(fd, (struct sockaddr *)&ss, &sslen) < 0) {
        error_setg_errno(errp, errno, "%s",
                         "Unable to query remote socket address");
        return NULL;
    }

    return socket_sockaddr_to_address(&ss, sslen, errp);
}


SocketAddress *socket_address_flatten(SocketAddressLegacy *addr_legacy)
{
    SocketAddress *addr;

    if (!addr_legacy) {
        return NULL;
    }

    addr = g_new(SocketAddress, 1);

    switch (addr_legacy->type) {
    case SOCKET_ADDRESS_LEGACY_KIND_INET:
        addr->type = SOCKET_ADDRESS_TYPE_INET;
        QAPI_CLONE_MEMBERS(InetSocketAddress, &addr->u.inet,
                           addr_legacy->u.inet.data);
        break;
    case SOCKET_ADDRESS_LEGACY_KIND_UNIX:
        addr->type = SOCKET_ADDRESS_TYPE_UNIX;
        QAPI_CLONE_MEMBERS(UnixSocketAddress, &addr->u.q_unix,
                           addr_legacy->u.q_unix.data);
        break;
    case SOCKET_ADDRESS_LEGACY_KIND_VSOCK:
        addr->type = SOCKET_ADDRESS_TYPE_VSOCK;
        QAPI_CLONE_MEMBERS(VsockSocketAddress, &addr->u.vsock,
                           addr_legacy->u.vsock.data);
        break;
    case SOCKET_ADDRESS_LEGACY_KIND_FD:
        addr->type = SOCKET_ADDRESS_TYPE_FD;
        QAPI_CLONE_MEMBERS(String, &addr->u.fd, addr_legacy->u.fd.data);
        break;
    default:
        abort();
    }

    return addr;
}