[PATCH v2] linux-user: Unconditionally use pipe2() syscall

[PATCH v2] linux-user: Unconditionally use pipe2() syscall

[Helge Deller]

The pipe2() syscall is available on all Linux platforms since kernel
2.6.27, so use it unconditionally to emulate pipe() and pipe2().

Signed-off-by: Helge Deller <deller@gmx.de>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
---
Changes in v2:
- added Reviewed-by: from Peter
- new diff against git head
- no functional changes


diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index 991b85e6b4..4f89184d05 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -1586,21 +1586,12 @@ static abi_long do_ppoll(abi_long arg1, abi_long arg2, abi_long arg3,
 }
 #endif

-static abi_long do_pipe2(int host_pipe[], int flags)
-{
-#ifdef CONFIG_PIPE2
-    return pipe2(host_pipe, flags);
-#else
-    return -ENOSYS;
-#endif
-}
-
 static abi_long do_pipe(CPUArchState *cpu_env, abi_ulong pipedes,
                         int flags, int is_pipe2)
 {
     int host_pipe[2];
     abi_long ret;
-    ret = flags ? do_pipe2(host_pipe, flags) : pipe(host_pipe);
+    ret = pipe2(host_pipe, flags);

     if (is_error(ret))
         return get_errno(ret);
diff --git a/meson.build b/meson.build
index 8a8c415fc1..75aaca8462 100644
--- a/meson.build
+++ b/meson.build
@@ -2026,15 +2026,6 @@ config_host_data.set('CONFIG_OPEN_BY_HANDLE', cc.links(gnu_source_prefix + '''
   #else
   int main(void) { struct file_handle fh; return open_by_handle_at(0, &fh, 0); }
   #endif'''))
-config_host_data.set('CONFIG_PIPE2', cc.links(gnu_source_prefix + '''
-  #include <unistd.h>
-  #include <fcntl.h>
-
-  int main(void)
-  {
-      int pipefd[2];
-      return pipe2(pipefd, O_CLOEXEC);
-  }'''))
 config_host_data.set('CONFIG_POSIX_MADVISE', cc.links(gnu_source_prefix + '''
   #include <sys/mman.h>
   #include <stddef.h>

Re: [PATCH v2] linux-user: Unconditionally use pipe2() syscall

[Laurent Vivier]

Le 19/07/2022 à 18:20, Helge Deller a écrit :
> The pipe2() syscall is available on all Linux platforms since kernel
> 2.6.27, so use it unconditionally to emulate pipe() and pipe2().
> 
> Signed-off-by: Helge Deller <deller@gmx.de>
> Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
> ---
> Changes in v2:
> - added Reviewed-by: from Peter
> - new diff against git head
> - no functional changes
> 
> 
> diff --git a/linux-user/syscall.c b/linux-user/syscall.c
> index 991b85e6b4..4f89184d05 100644
> --- a/linux-user/syscall.c
> +++ b/linux-user/syscall.c
> @@ -1586,21 +1586,12 @@ static abi_long do_ppoll(abi_long arg1, abi_long arg2, abi_long arg3,
>   }
>   #endif
> 
> -static abi_long do_pipe2(int host_pipe[], int flags)
> -{
> -#ifdef CONFIG_PIPE2
> -    return pipe2(host_pipe, flags);
> -#else
> -    return -ENOSYS;
> -#endif
> -}
> -
>   static abi_long do_pipe(CPUArchState *cpu_env, abi_ulong pipedes,
>                           int flags, int is_pipe2)
>   {
>       int host_pipe[2];
>       abi_long ret;
> -    ret = flags ? do_pipe2(host_pipe, flags) : pipe(host_pipe);
> +    ret = pipe2(host_pipe, flags);
> 
>       if (is_error(ret))
>           return get_errno(ret);
> diff --git a/meson.build b/meson.build
> index 8a8c415fc1..75aaca8462 100644
> --- a/meson.build
> +++ b/meson.build
> @@ -2026,15 +2026,6 @@ config_host_data.set('CONFIG_OPEN_BY_HANDLE', cc.links(gnu_source_prefix + '''
>     #else
>     int main(void) { struct file_handle fh; return open_by_handle_at(0, &fh, 0); }
>     #endif'''))
> -config_host_data.set('CONFIG_PIPE2', cc.links(gnu_source_prefix + '''
> -  #include <unistd.h>
> -  #include <fcntl.h>
> -
> -  int main(void)
> -  {
> -      int pipefd[2];
> -      return pipe2(pipefd, O_CLOEXEC);
> -  }'''))
>   config_host_data.set('CONFIG_POSIX_MADVISE', cc.links(gnu_source_prefix + '''
>     #include <sys/mman.h>
>     #include <stddef.h>

Applied to my linux-user-for-7.1 branch.

Thanks,
Laurent