Re: [Qemu-devel] [PATCH 1/2] This patch adds support for the pselect syscall in linux-user emulation and also adds several support functions required to translate the timespec structs between the target and the host.

[Riku Voipio <riku.voipio@iki.fi>]

On Tue, Feb 16, 2010 at 05:31:19AM -0500, Michael Casadevall wrote:
> Signed-off-by: Michael Casadevall <mcasadevall@ubuntu.com>

Looks correct and passes ltp tests, thanks. Will include these patches
in the next linux-user pull request.

Next time you might want to separate the commit title and message instead
of having all in the first line.

> ---
>  linux-user/syscall.c |  119 ++++++++++++++++++++++++++++++++++++++++++++++++++
>  1 files changed, 119 insertions(+), 0 deletions(-)
> 
> diff --git a/linux-user/syscall.c b/linux-user/syscall.c
> index 9fb493f..3663451 100644
> --- a/linux-user/syscall.c
> +++ b/linux-user/syscall.c
> @@ -850,6 +850,38 @@ static inline abi_long copy_to_user_timeval(abi_ulong target_tv_addr,
>      return 0;
>  }
>  
> +static inline abi_long copy_from_user_timespec(struct timespec *ts,
> +                                              abi_ulong target_ts_addr)
> +{
> +    struct target_timespec *target_ts;
> +
> +    if (!lock_user_struct(VERIFY_READ, target_ts, target_ts_addr, 1))
> +        return -TARGET_EFAULT;
> +
> +    __get_user(ts->tv_sec, &target_ts->tv_sec);
> +    __get_user(ts->tv_nsec, &target_ts->tv_nsec);
> +
> +    unlock_user_struct(target_ts, target_ts_addr, 0);
> +
> +    return 0;
> +}
> +
> +
> +static inline abi_long copy_to_user_timespec(abi_ulong target_ts_addr,
> +                                            const struct timespec *ts)
> +{
> +    struct target_timespec *target_ts;
> +
> +    if (!lock_user_struct(VERIFY_WRITE, target_ts, target_ts_addr, 0))
> +        return -TARGET_EFAULT;
> +
> +    __put_user(ts->tv_sec, &target_ts->tv_sec);
> +    __put_user(ts->tv_nsec, &target_ts->tv_nsec);
> +
> +    unlock_user_struct(target_ts, target_ts_addr, 1);
> +
> +    return 0;
> +}
>  #if defined(TARGET_NR_mq_open) && defined(__NR_mq_open)
>  #include <mqueue.h>
>  
> @@ -949,6 +981,75 @@ static abi_long do_select(int n,
>      return ret;
>  }
>  
> +#ifdef TARGET_NR_pselect6
> +/* do_pselect() must return target values and target errnos. */
> +static abi_long do_pselect(int n,
> +                          abi_ulong rfd_addr, abi_ulong wfd_addr,
> +                          abi_ulong efd_addr, abi_ulong target_tv_addr,
> +                          abi_ulong set_addr)
> +{
> +    fd_set rfds, wfds, efds;
> +    fd_set *rfds_ptr, *wfds_ptr, *efds_ptr;
> +    struct timespec tv, *tv_ptr;
> +    sigset_t set, *set_ptr;
> +    abi_long ret;
> +
> +    if (rfd_addr) {
> +        if (copy_from_user_fdset(&rfds, rfd_addr, n))
> +            return -TARGET_EFAULT;
> +        rfds_ptr = &rfds;
> +    } else {
> +        rfds_ptr = NULL;
> +    }
> +    if (wfd_addr) {
> +        if (copy_from_user_fdset(&wfds, wfd_addr, n))
> +            return -TARGET_EFAULT;
> +        wfds_ptr = &wfds;
> +    } else {
> +        wfds_ptr = NULL;
> +    }
> +    if (efd_addr) {
> +        if (copy_from_user_fdset(&efds, efd_addr, n))
> +            return -TARGET_EFAULT;
> +        efds_ptr = &efds;
> +    } else {
> +        efds_ptr = NULL;
> +    }
> +
> +    if (target_tv_addr) {
> +        if (copy_from_user_timespec(&tv, target_tv_addr))
> +            return -TARGET_EFAULT;
> +        tv_ptr = &tv;
> +    } else {
> +        tv_ptr = NULL;
> +    }
> +
> +    /* We don't need to return sigmask to target */
> +    if (set_addr) {
> +        target_to_host_old_sigset(&set, &set_addr);
> +        set_ptr = &set;
> +    } else {
> +        set_ptr = NULL;
> +    }
> +
> +    ret = get_errno(pselect(n, rfds_ptr, wfds_ptr, efds_ptr, tv_ptr, set_ptr));
> +
> +    if (!is_error(ret)) {
> +        if (rfd_addr && copy_to_user_fdset(rfd_addr, &rfds, n))
> +            return -TARGET_EFAULT;
> +        if (wfd_addr && copy_to_user_fdset(wfd_addr, &wfds, n))
> +            return -TARGET_EFAULT;
> +        if (efd_addr && copy_to_user_fdset(efd_addr, &efds, n))
> +            return -TARGET_EFAULT;
> +
> +        if (target_tv_addr && copy_to_user_timespec(target_tv_addr, &tv))
> +            return -TARGET_EFAULT;
> +    }
> +
> +    return ret;
> +}
> +#endif
> +
>  static abi_long do_pipe2(int host_pipe[], int flags)
>  {
>  #ifdef CONFIG_PIPE2
> @@ -5136,6 +5237,24 @@ abi_long do_syscall(void *cpu_env, int num, abi_long arg1,
>          }
>          break;
>  #endif
> +
> +#ifdef TARGET_NR_pselect6
> +    case TARGET_NR_pselect6:
> +        {
> +            abi_ulong inp, outp, exp, tvp, set;
> +            long nsel;
> +
> +            nsel = tswapl(arg1);
> +            inp = tswapl(arg2);
> +            outp = tswapl(arg3);
> +            exp = tswapl(arg4);
> +            tvp = tswapl(arg5);
> +            set = tswapl(arg6);
> +
> +            ret = do_pselect(nsel, inp, outp, exp, tvp, set);
> +        }
> +        break;
> +#endif
>      case TARGET_NR_symlink:
>          {
>              void *p2;
> -- 
> 1.6.6.1
> 
>