syscall.c

qemu虚拟机代码

    if (wfd_p) {
        target_wfds = lock_user(wfd_p, sizeof(target_long) * n, 1);
        wfds_ptr = target_to_host_fds(&wfds, target_wfds, n);
    } else {
        target_wfds = NULL;
        wfds_ptr = NULL;
    }
    if (efd_p) {
        target_efds = lock_user(efd_p, sizeof(target_long) * n, 1);
        efds_ptr = target_to_host_fds(&efds, target_efds, n);
    } else {
        target_efds = NULL;
        efds_ptr = NULL;
    }
            
    if (target_tv) {
        target_to_host_timeval(&tv, target_tv);
        tv_ptr = &tv;
    } else {
        tv_ptr = NULL;
    }
    ret = get_errno(select(n, rfds_ptr, wfds_ptr, efds_ptr, tv_ptr));
    ok = !is_error(ret);

    if (ok) {
        host_to_target_fds(target_rfds, rfds_ptr, n);
        host_to_target_fds(target_wfds, wfds_ptr, n);
        host_to_target_fds(target_efds, efds_ptr, n);

        if (target_tv) {
            host_to_target_timeval(target_tv, &tv);
        }
    }
    if (target_rfds)
        unlock_user(target_rfds, rfd_p, ok ? sizeof(target_long) * n : 0);
    if (target_wfds)
        unlock_user(target_wfds, wfd_p, ok ? sizeof(target_long) * n : 0);
    if (target_efds)
        unlock_user(target_efds, efd_p, ok ? sizeof(target_long) * n : 0);

    return ret;
}

static inline void target_to_host_sockaddr(struct sockaddr *addr,
                                           target_ulong target_addr,
                                           socklen_t len)
{
    struct target_sockaddr *target_saddr;

    target_saddr = lock_user(target_addr, len, 1);
    memcpy(addr, target_saddr, len);
    addr->sa_family = tswap16(target_saddr->sa_family);
    unlock_user(target_saddr, target_addr, 0);
}

static inline void host_to_target_sockaddr(target_ulong target_addr,
                                           struct sockaddr *addr,
                                           socklen_t len)
{
    struct target_sockaddr *target_saddr;

    target_saddr = lock_user(target_addr, len, 0);
    memcpy(target_saddr, addr, len);
    target_saddr->sa_family = tswap16(addr->sa_family);
    unlock_user(target_saddr, target_addr, len);
}

/* ??? Should this also swap msgh->name?  */
static inline void target_to_host_cmsg(struct msghdr *msgh,
                                       struct target_msghdr *target_msgh)
{
    struct cmsghdr *cmsg = CMSG_FIRSTHDR(msgh);
    struct target_cmsghdr *target_cmsg = TARGET_CMSG_FIRSTHDR(target_msgh);
    socklen_t space = 0;

    while (cmsg && target_cmsg) {
        void *data = CMSG_DATA(cmsg);
        void *target_data = TARGET_CMSG_DATA(target_cmsg);

        int len = tswapl(target_cmsg->cmsg_len) 
                  - TARGET_CMSG_ALIGN(sizeof (struct target_cmsghdr));

        space += CMSG_SPACE(len);
        if (space > msgh->msg_controllen) {
            space -= CMSG_SPACE(len);
            gemu_log("Host cmsg overflow\n");
            break;
        }

        cmsg->cmsg_level = tswap32(target_cmsg->cmsg_level);
        cmsg->cmsg_type = tswap32(target_cmsg->cmsg_type);
        cmsg->cmsg_len = CMSG_LEN(len);

        if (cmsg->cmsg_level != SOL_SOCKET || cmsg->cmsg_type != SCM_RIGHTS) {
            gemu_log("Unsupported ancillary data: %d/%d\n", cmsg->cmsg_level, cmsg->cmsg_type);
            memcpy(data, target_data, len);
        } else {
            int *fd = (int *)data;
            int *target_fd = (int *)target_data;
            int i, numfds = len / sizeof(int);

            for (i = 0; i < numfds; i++)
                fd[i] = tswap32(target_fd[i]);
        }

        cmsg = CMSG_NXTHDR(msgh, cmsg);
        target_cmsg = TARGET_CMSG_NXTHDR(target_msgh, target_cmsg);
    }

    msgh->msg_controllen = space;
}

/* ??? Should this also swap msgh->name?  */
static inline void host_to_target_cmsg(struct target_msghdr *target_msgh,
                                       struct msghdr *msgh)
{
    struct cmsghdr *cmsg = CMSG_FIRSTHDR(msgh);
    struct target_cmsghdr *target_cmsg = TARGET_CMSG_FIRSTHDR(target_msgh);
    socklen_t space = 0;

    while (cmsg && target_cmsg) {
        void *data = CMSG_DATA(cmsg);
        void *target_data = TARGET_CMSG_DATA(target_cmsg);

        int len = cmsg->cmsg_len - CMSG_ALIGN(sizeof (struct cmsghdr));

        space += TARGET_CMSG_SPACE(len);
        if (space > tswapl(target_msgh->msg_controllen)) {
            space -= TARGET_CMSG_SPACE(len);
            gemu_log("Target cmsg overflow\n");
            break;
        }

        target_cmsg->cmsg_level = tswap32(cmsg->cmsg_level);
        target_cmsg->cmsg_type = tswap32(cmsg->cmsg_type);
        target_cmsg->cmsg_len = tswapl(TARGET_CMSG_LEN(len));

        if (cmsg->cmsg_level != SOL_SOCKET || cmsg->cmsg_type != SCM_RIGHTS) {
            gemu_log("Unsupported ancillary data: %d/%d\n", cmsg->cmsg_level, cmsg->cmsg_type);
            memcpy(target_data, data, len);
        } else {
            int *fd = (int *)data;
            int *target_fd = (int *)target_data;
            int i, numfds = len / sizeof(int);

            for (i = 0; i < numfds; i++)
                target_fd[i] = tswap32(fd[i]);
        }

        cmsg = CMSG_NXTHDR(msgh, cmsg);
        target_cmsg = TARGET_CMSG_NXTHDR(target_msgh, target_cmsg);
    }

    msgh->msg_controllen = tswapl(space);
}

static long do_setsockopt(int sockfd, int level, int optname, 
                          target_ulong optval, socklen_t optlen)
{
    int val, ret;
            
    switch(level) {
    case SOL_TCP:
        /* TCP options all take an 'int' value.  */
        if (optlen < sizeof(uint32_t))
            return -EINVAL;
        
        val = tget32(optval);
        ret = get_errno(setsockopt(sockfd, level, optname, &val, sizeof(val)));
        break;
    case SOL_IP:
        switch(optname) {
        case IP_TOS:
        case IP_TTL:
        case IP_HDRINCL:
        case IP_ROUTER_ALERT:
        case IP_RECVOPTS:
        case IP_RETOPTS:
        case IP_PKTINFO:
        case IP_MTU_DISCOVER:
        case IP_RECVERR:
        case IP_RECVTOS:
#ifdef IP_FREEBIND
        case IP_FREEBIND:
#endif
        case IP_MULTICAST_TTL:
        case IP_MULTICAST_LOOP:
            val = 0;
            if (optlen >= sizeof(uint32_t)) {
                val = tget32(optval);
            } else if (optlen >= 1) {
                val = tget8(optval);
            }
            ret = get_errno(setsockopt(sockfd, level, optname, &val, sizeof(val)));
            break;
        default:
            goto unimplemented;
        }
        break;
    case SOL_SOCKET:
        switch (optname) {
            /* Options with 'int' argument.  */
        case SO_DEBUG:
        case SO_REUSEADDR:
        case SO_TYPE:
        case SO_ERROR:
        case SO_DONTROUTE:
        case SO_BROADCAST:
        case SO_SNDBUF:
        case SO_RCVBUF:
        case SO_KEEPALIVE:
        case SO_OOBINLINE:
        case SO_NO_CHECK:
        case SO_PRIORITY:
#ifdef SO_BSDCOMPAT
        case SO_BSDCOMPAT:
#endif
        case SO_PASSCRED:
        case SO_TIMESTAMP:
        case SO_RCVLOWAT:
        case SO_RCVTIMEO:
        case SO_SNDTIMEO:
            if (optlen < sizeof(uint32_t))
                return -EINVAL;

            val = tget32(optval);
            ret = get_errno(setsockopt(sockfd, level, optname, &val, sizeof(val)));
            break;
        default:
            goto unimplemented;
        }
        break;
    default:
    unimplemented:
        gemu_log("Unsupported setsockopt level=%d optname=%d \n", level, optname);
        ret = -ENOSYS;
    }
    return ret;
}

static long do_getsockopt(int sockfd, int level, int optname, 
                          target_ulong optval, target_ulong optlen)
{
    int len, lv, val, ret;

    switch(level) {
    case SOL_SOCKET:
	switch (optname) {
	case SO_LINGER:
	case SO_RCVTIMEO:
	case SO_SNDTIMEO:
	case SO_PEERCRED:
	case SO_PEERNAME:
	    /* These don't just return a single integer */
	    goto unimplemented;
        default:
            goto int_case;
        }
        break;
    case SOL_TCP:
        /* TCP options all take an 'int' value.  */
    int_case:
        len = tget32(optlen);
        if (len < 0)
            return -EINVAL;
        lv = sizeof(int);
        ret = get_errno(getsockopt(sockfd, level, optname, &val, &lv));
        if (ret < 0)
            return ret;
        val = tswap32(val);
        if (len > lv)
            len = lv;
        if (len == 4)
            tput32(optval, val);
        else
            tput8(optval, val);
        tput32(optlen, len);
        break;
    case SOL_IP:
        switch(optname) {
        case IP_TOS:
        case IP_TTL:
        case IP_HDRINCL:
        case IP_ROUTER_ALERT:
        case IP_RECVOPTS:
        case IP_RETOPTS:
        case IP_PKTINFO:
        case IP_MTU_DISCOVER:
        case IP_RECVERR:
        case IP_RECVTOS:
#ifdef IP_FREEBIND
        case IP_FREEBIND:
#endif
        case IP_MULTICAST_TTL:
        case IP_MULTICAST_LOOP:
            len = tget32(optlen);
            if (len < 0)
                return -EINVAL;
            lv = sizeof(int);
            ret = get_errno(getsockopt(sockfd, level, optname, &val, &lv));
            if (ret < 0)
                return ret;
            if (len < sizeof(int) && len > 0 && val >= 0 && val < 255) {
                len = 1;
                tput32(optlen, len);
                tput8(optval, val);
            } else {
                if (len > sizeof(int))
                    len = sizeof(int);
                tput32(optlen, len);
                tput32(optval, val);
            }
            break;
        default:
            goto unimplemented;
        }
        break;
    default:
    unimplemented:
        gemu_log("getsockopt level=%d optname=%d not yet supported\n",
                 level, optname);
        ret = -ENOSYS;
        break;
    }
    return ret;
}

static void lock_iovec(struct iovec *vec, target_ulong target_addr,
                       int count, int copy)
{
    struct target_iovec *target_vec;
    target_ulong base;
    int i;

    target_vec = lock_user(target_addr, count * sizeof(struct target_iovec), 1);
    for(i = 0;i < count; i++) {
        base = tswapl(target_vec[i].iov_base);
        vec[i].iov_len = tswapl(target_vec[i].iov_len);
        vec[i].iov_base = lock_user(base, vec[i].iov_len, copy);
    }
    unlock_user (target_vec, target_addr, 0);
}

static void unlock_iovec(struct iovec *vec, target_ulong target_addr,
                         int count, int copy)
{
    struct target_iovec *target_vec;
    target_ulong base;
    int i;

    target_vec = lock_user(target_addr, count * sizeof(struct target_iovec), 1);
    for(i = 0;i < count; i++) {
        base = tswapl(target_vec[i].iov_base);
        unlock_user(vec[i].iov_base, base, copy ? vec[i].iov_len : 0);
    }
    unlock_user (target_vec, target_addr, 0);
}

static long do_socketcall(int num, target_ulong vptr)
{
    long ret;
    const int n = sizeof(target_ulong);

    switch(num) {
    case SOCKOP_socket:
	{
            int domain = tgetl(vptr);
            int type = tgetl(vptr + n);
            int protocol = tgetl(vptr + 2 * n);

            ret = get_errno(socket(domain, type, protocol));
	}
        break;
    case SOCKOP_bind:
	{
            int sockfd = tgetl(vptr);
            target_ulong target_addr = tgetl(vptr + n);
            socklen_t addrlen = tgetl(vptr + 2 * n);
            void *addr = alloca(addrlen);

            target_to_host_sockaddr(addr, target_addr, addrlen);
            ret = get_errno(bind(sockfd, addr, addrlen));
        }
        break;
    case SOCKOP_connect:
        {
            int sockfd = tgetl(vptr);
            target_ulong target_addr = tgetl(vptr + n);
            socklen_t addrlen = tgetl(vptr + 2 * n);
            void *addr = alloca(addrlen);

            target_to_host_sockaddr(addr, target_addr, addrlen);
            ret = get_errno(connect(sockfd, addr, addrlen));
        }
        break;
    case SOCKOP_listen:
        {
            int sockfd = tgetl(vptr);
            int backlog = tgetl(vptr + n);

            ret = get_errno(listen(sockfd, backlog));
        }
        break;
    case SOCKOP_accept:
        {
            int sockfd = tgetl(vptr);
            target_ulong target_addr = tgetl(vptr + n);
            target_ulong target_addrlen = tgetl(vptr + 2 * n);
            socklen_t addrlen = tget32(target_addrlen);
            void *addr = alloca(addrlen);

            ret = get_errno(accept(sockfd, addr, &addrlen));
            if (!is_error(ret)) {
                host_to_target_sockaddr(target_addr, addr, addrlen);
                tput32(target_addrlen, addrlen);
            }
        }
        break;
    case SOCKOP_getsockname:
        {
            int sockfd = tgetl(vptr);
            target_ulong target_addr = tgetl(vptr + n);
            target_ulong target_addrlen = tgetl(vptr + 2 * n);