Re: [PATCH] linux-user: fix pidfd_send_signal()

[Helge Deller]

On 10/5/22 18:38, Laurent Vivier wrote:
> According to pidfd_send_signal(2), info argument can be a NULL pointer.
> Fix strace to correctly manage ending comma in parameters.
>
> Fixes: cc054c6f13 ("linux-user: Add pidfd_open(), pidfd_send_signal() and 
> pidfd_getfd() syscalls")
> cc: Helge Deller <deller@gmx.de>
> Signed-off-by: Laurent Vivier <laurent@vivier.eu>


Reviewed-by: Helge Deller <deller@gmx.de>



> ---
>   linux-user/strace.c  |  4 ++--
>   linux-user/syscall.c | 19 ++++++++++++-------
>   2 files changed, 14 insertions(+), 9 deletions(-)
>
> diff --git a/linux-user/strace.c b/linux-user/strace.c
> index 37bc96df9bb6..86c081c83f74 100644
> --- a/linux-user/strace.c
> +++ b/linux-user/strace.c
> @@ -3383,10 +3383,10 @@ print_pidfd_send_signal(CPUArchState *cpu_env, const 
> struct syscallname *name,
>
>           unlock_user(p, arg2, 0);
>       } else {
> -        print_pointer(arg2, 1);
> +        print_pointer(arg2, 0);
>       }
>
> -    print_raw_param("%u", arg3, 0);
> +    print_raw_param("%u", arg3, 1);
>       print_syscall_epilogue(name);
>   }
>   #endif
> diff --git a/linux-user/syscall.c b/linux-user/syscall.c
> index 2e954d8dbd9e..b1493917ee07 100644
> --- a/linux-user/syscall.c
> +++ b/linux-user/syscall.c
> @@ -8679,16 +8679,21 @@ static abi_long do_syscall1(CPUArchState *cpu_env, int 
> num, abi_long arg1,
>   #if defined(__NR_pidfd_send_signal) && defined(TARGET_NR_pidfd_send_signal)
>       case TARGET_NR_pidfd_send_signal:
>           {
> -            siginfo_t uinfo;
> +            siginfo_t uinfo, *puinfo;
>
> -            p = lock_user(VERIFY_READ, arg3, sizeof(target_siginfo_t), 1);
> -            if (!p) {
> -                return -TARGET_EFAULT;
> +            if (arg3) {
> +                p = lock_user(VERIFY_READ, arg3, sizeof(target_siginfo_t), 1);
> +                if (!p) {
> +                    return -TARGET_EFAULT;
> +                 }
> +                 target_to_host_siginfo(&uinfo, p);
> +                 unlock_user(p, arg3, 0);
> +                 puinfo = &uinfo;
> +            } else {
> +                 puinfo = NULL;
>               }
> -            target_to_host_siginfo(&uinfo, p);
> -            unlock_user(p, arg3, 0);
>               ret = get_errno(pidfd_send_signal(arg1, 
> target_to_host_signal(arg2),
> -                &uinfo, arg4));
> +                                              puinfo, arg4));
>           }
>           return ret;
>   #endif