On Tue, Feb 22, 2011 at 01:02:26PM +0000, Peter Maydell wrote:
> When emulating a 32 bit Linux user-mode program on a 64 bit target
> we implement the llseek syscall in terms of lseek. Correct a bug
> which meant we were silently casting the result of host lseek()
> to a 32 bit integer as it passed through get_errno() and thus
> throwing away the top half.
>
> We also don't try to store the result back to userspace unless
> the seek succeeded; this matches the kernel behaviour.
>
> Thanks to Eoghan Sherry for identifying the problem and suggesting
> a solution.
>
> Signed-off-by: Peter Maydell <peter.mayd...@linaro.org>
> ---
> linux-user/syscall.c | 16 ++++++++++------
> 1 files changed, 10 insertions(+), 6 deletions(-)
Thanks, applied.
> diff --git a/linux-user/syscall.c b/linux-user/syscall.c
> index cf8a4c3..23d7a63 100644
> --- a/linux-user/syscall.c
> +++ b/linux-user/syscall.c
> @@ -6127,16 +6127,20 @@ abi_long do_syscall(void *cpu_env, int num, abi_long
> arg1,
> #ifdef TARGET_NR__llseek /* Not on alpha */
> case TARGET_NR__llseek:
> {
> + int64_t res;
> #if !defined(__NR_llseek)
> - ret = get_errno(lseek(arg1, ((uint64_t )arg2 << 32) | arg3,
> arg5));
> - if (put_user_s64(ret, arg4))
> - goto efault;
> + res = lseek(arg1, ((uint64_t)arg2 << 32) | arg3, arg5);
> + if (res == -1) {
> + ret = get_errno(res);
> + } else {
> + ret = 0;
> + }
> #else
> - int64_t res;
> ret = get_errno(_llseek(arg1, arg2, arg3, &res, arg5));
> - if (put_user_s64(res, arg4))
> - goto efault;
> #endif
> + if ((ret == 0) && put_user_s64(res, arg4)) {
> + goto efault;
> + }
> }
> break;
> #endif
> --
> 1.7.1
>
>
>
--
Aurelien Jarno GPG: 1024D/F1BCDB73
aurel...@aurel32.net http://www.aurel32.net
