linux-user: implement renameat2

This is needed for new architectures like RISC-V which do not provide any
other rename-like syscall.

Signed-off-by: Andreas Schwab <schwab@suse.de>
---
 linux-user/syscall.c | 33 +++++++++++++++++++++++++++++++++
 1 file changed, 33 insertions(+)

Hi,

This series seems to have some coding style problems. See output below for
more information:

Type: series
Message-id: mvmk1w9lreq.fsf@suse.de
Subject: [Qemu-devel] [PATCH] linux-user: implement renameat2

=== TEST SCRIPT BEGIN ===
#!/bin/bash

BASE=base
n=1
total=$(git log --oneline $BASE.. | wc -l)
failed=0

git config --local diff.renamelimit 0
git config --local diff.renames True

commits="$(git log --format=%H --reverse $BASE..)"
for c in $commits; do
    echo "Checking PATCH $n/$total: $(git log -n 1 --format=%s $c)..."
    if ! git show $c --format=email | ./scripts/checkpatch.pl --mailback -; then
        failed=1
        echo
    fi
    n=$((n+1))
done

exit $failed
=== TEST SCRIPT END ===

Updating 3c8cf5a9c21ff8782164d1def7f44bd888713384
From https://github.com/patchew-project/qemu
 t [tag update]            patchew/1516611841-5526-1-git-send-email-anton.nefedov@virtuozzo.com -> patchew/1516611841-5526-1-git-send-email-anton.nefedov@virtuozzo.com
 * [new tag]               patchew/mvmk1w9lreq.fsf@suse.de -> patchew/mvmk1w9lreq.fsf@suse.de
Switched to a new branch 'test'
59d79798ac linux-user: implement renameat2

=== OUTPUT BEGIN ===
Checking PATCH 1/1: linux-user: implement renameat2...
WARNING: architecture specific defines should be avoided
#21: FILE: linux-user/syscall.c:602:
+#if defined(__NR_renameat2)

ERROR: spaces required around that '*' (ctx:WxV)
#27: FILE: linux-user/syscall.c:608:
+                         int newfd, const chat *new, int flags)
                                                ^

ERROR: braces {} are necessary for all arms of this statement
#29: FILE: linux-user/syscall.c:610:
+    if (flags == 0)
[...]

ERROR: braces {} are necessary for all arms of this statement
#50: FILE: linux-user/syscall.c:8368:
+            if (!p || !p2)
[...]
+            else
[...]

ERROR: line over 90 characters
#54: FILE: linux-user/syscall.c:8372:
+                                              target_to_host_bitmask(arg5, fcntl_flags_tbl)));

total: 4 errors, 1 warnings, 45 lines checked

Your patch has style problems, please review.  If any of these errors
are false positives report them to the maintainer, see
CHECKPATCH in MAINTAINERS.

=== OUTPUT END ===

Test command exited with code: 1


---
Email generated automatically by Patchew [http://patchew.org/].
Please send your feedback to patchew-devel@freelists.org

Le 22/01/2018 à 18:44, Andreas Schwab a écrit :
> This is needed for new architectures like RISC-V which do not provide any
> other rename-like syscall.
> 
> Signed-off-by: Andreas Schwab <schwab@suse.de>
> ---
>  linux-user/syscall.c | 33 +++++++++++++++++++++++++++++++++
>  1 file changed, 33 insertions(+)
> 
> diff --git a/linux-user/syscall.c b/linux-user/syscall.c
> index 5e54889522..12ca06c65a 100644
> --- a/linux-user/syscall.c
> +++ b/linux-user/syscall.c
> @@ -598,6 +598,23 @@ static int sys_utimensat(int dirfd, const char *pathname,
>  #endif
>  #endif /* TARGET_NR_utimensat */
>  
> +#ifdef TARGET_NR_renameat2
> +#if defined(__NR_renameat2)
> +#define __NR_sys_renameat2 __NR_renameat2
> +_syscall5(int, sys_renameat2, int, oldfd, const char *, old, int, newfd,
> +          const char *, new, unsigned int, flags)
> +#else
> +static int sys_renameat2(int oldfd, const char *old,
> +                         int newfd, const chat *new, int flags)
> +{
> +    if (flags == 0)
> +        return renameat(oldfd, old, newfd, new);

Please fix style problem reported by patchew
(or ./scripts/checkpatch.pl)

> +    errno = ENOSYS;
> +    return -1;
> +}
> +#endif
> +#endif /* TARGET_NR_renameat2 */
> +
>  #ifdef CONFIG_INOTIFY
>  #include <sys/inotify.h>
>  
> @@ -8342,6 +8359,22 @@ abi_long do_syscall(void *cpu_env, int num, abi_long arg1,
>          }
>          break;
>  #endif
> +#if defined(TARGET_NR_renameat2)
> +    case TARGET_NR_renameat2:
> +        {
> +            void *p2;
> +            p  = lock_user_string(arg2);
> +            p2 = lock_user_string(arg4);
> +            if (!p || !p2)
> +                ret = -TARGET_EFAULT;
> +            else
> +                ret = get_errno(sys_renameat2(arg1, p, arg3, p2,
> +                                              target_to_host_bitmask(arg5, fcntl_flags_tbl)));

You can't use fcntl_flags_tbl
(because it converts fcntl/open flags O_*).

I think you can provide directly arg5 to sys_renameat2() because flags
are the same for all architectures (and value is already byte-swapped).

Thanks,
Laurent

Le 22/01/2018 à 18:44, Andreas Schwab a écrit :
> This is needed for new architectures like RISC-V which do not provide any
> other rename-like syscall.
> 
> Signed-off-by: Andreas Schwab <schwab@suse.de>
> ---
>  linux-user/syscall.c | 33 +++++++++++++++++++++++++++++++++
>  1 file changed, 33 insertions(+)
> 
> diff --git a/linux-user/syscall.c b/linux-user/syscall.c
> index 5e54889522..12ca06c65a 100644
> --- a/linux-user/syscall.c
> +++ b/linux-user/syscall.c
> @@ -598,6 +598,23 @@ static int sys_utimensat(int dirfd, const char *pathname,
>  #endif
>  #endif /* TARGET_NR_utimensat */
>  
> +#ifdef TARGET_NR_renameat2
> +#if defined(__NR_renameat2)
> +#define __NR_sys_renameat2 __NR_renameat2
> +_syscall5(int, sys_renameat2, int, oldfd, const char *, old, int, newfd,
> +          const char *, new, unsigned int, flags)
> +#else
> +static int sys_renameat2(int oldfd, const char *old,
> +                         int newfd, const chat *new, int flags)

"const char *" would look better.

And, please, test it (build/run).

Thanks,
Laurent

On Jan 23 2018, Laurent Vivier <laurent@vivier.eu> wrote:

> Please fix style problem reported by patchew
> (or ./scripts/checkpatch.pl)

This was mostly copy-pasted from surrounding code. :-)

>> @@ -8342,6 +8359,22 @@ abi_long do_syscall(void *cpu_env, int num, abi_long arg1,
>>          }
>>          break;
>>  #endif
>> +#if defined(TARGET_NR_renameat2)
>> +    case TARGET_NR_renameat2:
>> +        {
>> +            void *p2;
>> +            p  = lock_user_string(arg2);
>> +            p2 = lock_user_string(arg4);
>> +            if (!p || !p2)
>> +                ret = -TARGET_EFAULT;
>> +            else
>> +                ret = get_errno(sys_renameat2(arg1, p, arg3, p2,
>> +                                              target_to_host_bitmask(arg5, fcntl_flags_tbl)));
>
> You can't use fcntl_flags_tbl

Of course!  I was confused by another patch I was working on which does
need such a conversion. :-/

Andreas.

On Jan 23 2018, Laurent Vivier <laurent@vivier.eu> wrote:

> And, please, test it (build/run).

This was tested by bootstrapping openSUSE Factory for RISC-V.

Andreas.

Le 23/01/2018 à 11:26, Andreas Schwab a écrit :
> On Jan 23 2018, Laurent Vivier <laurent@vivier.eu> wrote:
> 
>> And, please, test it (build/run).
> 
> This was tested by bootstrapping openSUSE Factory for RISC-V.

I have no doubt on this part, but you should test the "#else" part too,
by, for instance, undefining "__NR_renameat2" locally/temporarily.

Thanks,
Laurent