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Re: [Qemu-devel] [PATCH v3 2/3] linux-user: Add support for semtimedop()
From: |
Laurent Vivier |
Subject: |
Re: [Qemu-devel] [PATCH v3 2/3] linux-user: Add support for semtimedop() syscall |
Date: |
Tue, 30 Oct 2018 15:01:48 +0100 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.2.1 |
Le 30/10/2018 à 13:55, Aleksandar Markovic a écrit :
> From: Aleksandar Rikalo <address@hidden>
>
> Add support for semtimedop() emulation. It is based on invocation
> of safe_semtimedop().
>
> Conversion is left out of safe_semtimedop(), since other safe_xxx()
> usually don't contain similar conversions.
>
> Signed-off-by: Aleksandar Rikalo <address@hidden>
> Signed-off-by: Aleksandar Markovic <address@hidden>
> ---
> linux-user/syscall.c | 36 ++++++++++++++++++++++++++++++++++++
> 1 file changed, 36 insertions(+)
>
> diff --git a/linux-user/syscall.c b/linux-user/syscall.c
> index 1d3aaf5..709d9a7 100644
> --- a/linux-user/syscall.c
> +++ b/linux-user/syscall.c
> @@ -6384,7 +6384,39 @@ static inline abi_long host_to_target_statx(struct
> target_statx *host_stx,
> return 0;
> }
> #endif
> +#ifdef TARGET_NR_semtimedop
> +static inline abi_long do_semtimedop(int semid, abi_long ptr, unsigned nsops,
> + abi_long timeout)
> +{
> + struct sembuf *sops;
> + struct timespec ts, *pts;
> + abi_long ret;
> +
> + if (timeout) {
> + pts = &ts;
> + if (target_to_host_timespec(pts, timeout)) {
> + return -TARGET_EFAULT;
> + }
> + } else {
> + pts = NULL;
> + }
>
> + sops = g_malloc(sizeof(struct sembuf) * nsops);
> + if (sops == NULL) {
> + return -TARGET_EFAULT;
> + }
> +
> + if (target_to_host_sembuf(sops, ptr, nsops)) {
> + g_free(sops);
> + return -TARGET_EFAULT;
> + }
> +
> + ret = get_errno(safe_semtimedop(semid, sops, nsops, pts));
> + g_free(sops);
> +
> + return ret;
> +}
> +#endif
>
> /* ??? Using host futex calls even when target atomic operations
> are not really atomic probably breaks things. However implementing
> @@ -8888,6 +8920,10 @@ static abi_long do_syscall1(void *cpu_env, int num,
> abi_long arg1,
> case TARGET_NR_semop:
> return do_semop(arg1, arg2, arg3);
> #endif
> +#ifdef TARGET_NR_semtimedop
> + case TARGET_NR_semtimedop:
> + return do_semtimedop(arg1, arg2, arg3, arg4);
> +#endif
> #ifdef TARGET_NR_semctl
> case TARGET_NR_semctl:
> return do_semctl(arg1, arg2, arg3, arg4);
>
To avoid duplicate code (and cleanup the stack allocation), you should
remove do_semop() and call do_semtimedop(..., NULL) from IPCOP_semop
and TARGET_NR_semop.
Thanks,
Laurent