diff mbox

[12/16] linux-user: support {name_to, open_by}_handle_at syscalls

Message ID 1402849113-11402-13-git-send-email-paul@archlinuxmips.org
State New
Headers show

Commit Message

Paul Burton June 15, 2014, 4:18 p.m. UTC
Implement support for the name_to_handle_at and open_by_handle_at
syscalls, allowing their use by the target program.

Signed-off-by: Paul Burton <paul@archlinuxmips.org>
---
 linux-user/strace.c    | 30 ++++++++++++++++++++++++++++++
 linux-user/strace.list |  6 ++++++
 linux-user/syscall.c   | 50 ++++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 86 insertions(+)

Comments

Riku Voipio Aug. 26, 2014, 12:30 p.m. UTC | #1
Hi Paul,

On Sun, Jun 15, 2014 at 05:18:29PM +0100, Paul Burton wrote:
> Implement support for the name_to_handle_at and open_by_handle_at
> syscalls, allowing their use by the target program. 

What was your testcase for these syscalls? I usually use LTP for testing
syscalls, but there is no testcase for name_to_handle_at and
open_by_handle_at.

Riku

> Signed-off-by: Paul Burton <paul@archlinuxmips.org>
> ---
>  linux-user/strace.c    | 30 ++++++++++++++++++++++++++++++
>  linux-user/strace.list |  6 ++++++
>  linux-user/syscall.c   | 50 ++++++++++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 86 insertions(+)
> 
> diff --git a/linux-user/strace.c b/linux-user/strace.c
> index ea6c1d2..c20ddf1 100644
> --- a/linux-user/strace.c
> +++ b/linux-user/strace.c
> @@ -1552,6 +1552,36 @@ print_kill(const struct syscallname *name,
>  }
>  #endif
>  
> +#ifdef TARGET_NR_name_to_handle_at
> +static void
> +print_name_to_handle_at(const struct syscallname *name,
> +    abi_long arg0, abi_long arg1, abi_long arg2,
> +    abi_long arg3, abi_long arg4, abi_long arg5)
> +{
> +    print_syscall_prologue(name);
> +    print_at_dirfd(arg0, 0);
> +    print_string(arg1, 0);
> +    print_pointer(arg2, 0);
> +    print_pointer(arg3, 0);
> +    print_raw_param("0x%x", arg4, 1);
> +    print_syscall_epilogue(name);
> +}
> +#endif
> +
> +#ifdef TARGET_NR_open_by_handle_at
> +static void
> +print_open_by_handle_at(const struct syscallname *name,
> +    abi_long arg0, abi_long arg1, abi_long arg2,
> +    abi_long arg3, abi_long arg4, abi_long arg5)
> +{
> +    print_syscall_prologue(name);
> +    print_raw_param("%d", arg0, 0);
> +    print_pointer(arg2, 0);
> +    print_open_flags(arg3, 1);
> +    print_syscall_epilogue(name);
> +}
> +#endif
> +
>  /*
>   * An array of all of the syscalls we know about
>   */
> diff --git a/linux-user/strace.list b/linux-user/strace.list
> index 8de972a..147f579 100644
> --- a/linux-user/strace.list
> +++ b/linux-user/strace.list
> @@ -582,6 +582,9 @@
>  #ifdef TARGET_NR_munmap
>  { TARGET_NR_munmap, "munmap" , NULL, print_munmap, NULL },
>  #endif
> +#ifdef TARGET_NR_name_to_handle_at
> +{ TARGET_NR_name_to_handle_at, "name_to_handle_at" , NULL, print_name_to_handle_at, NULL },
> +#endif
>  #ifdef TARGET_NR_nanosleep
>  { TARGET_NR_nanosleep, "nanosleep" , NULL, NULL, NULL },
>  #endif
> @@ -624,6 +627,9 @@
>  #ifdef TARGET_NR_openat
>  { TARGET_NR_openat, "openat" , NULL, print_openat, NULL },
>  #endif
> +#ifdef TARGET_NR_open_by_handle_at
> +{ TARGET_NR_open_by_handle_at, "open_by_handle_at" , NULL, print_open_by_handle_at, NULL },
> +#endif
>  #ifdef TARGET_NR_osf_adjtime
>  { TARGET_NR_osf_adjtime, "osf_adjtime" , NULL, NULL, NULL },
>  #endif
> diff --git a/linux-user/syscall.c b/linux-user/syscall.c
> index c7f176a..192ad3a 100644
> --- a/linux-user/syscall.c
> +++ b/linux-user/syscall.c
> @@ -5349,6 +5349,56 @@ abi_long do_syscall(void *cpu_env, int num, abi_long arg1,
>          unlock_user(p, arg2, 0);
>          break;
>  #endif
> +#ifdef TARGET_NR_name_to_handle_at
> +    case TARGET_NR_name_to_handle_at:
> +        {
> +            struct file_handle *fh;
> +            uint32_t sz;
> +            int mount_id;
> +
> +            if (!(p = lock_user_string(arg2)))
> +                goto efault;
> +
> +            if (get_user_u32(sz, arg3)) {
> +                unlock_user(p, arg2, 0);
> +                goto efault;
> +            }
> +
> +            if (!(fh = lock_user(VERIFY_WRITE, arg3, sizeof(*fh) + sz, 1))) {
> +                unlock_user(p, arg2, 0);
> +                goto efault;
> +            }
> +
> +            ret = get_errno(name_to_handle_at(arg1, path(p), fh,
> +                                              &mount_id, arg5));
> +
> +            unlock_user(p, arg2, 0);
> +            unlock_user(p, arg3, sizeof(*fh) + sz);
> +
> +            if (put_user_s32(mount_id, arg4))
> +                goto efault;
> +        }
> +        break;
> +#endif
> +#ifdef TARGET_NR_open_by_handle_at
> +    case TARGET_NR_open_by_handle_at:
> +        {
> +            struct file_handle *fh;
> +            uint32_t sz;
> +
> +            if (get_user_u32(sz, arg2))
> +                goto efault;
> +
> +            if (!(fh = lock_user(VERIFY_WRITE, arg2, sizeof(*fh) + sz, 1)))
> +                goto efault;
> +
> +            ret = get_errno(open_by_handle_at(arg1, fh,
> +                    target_to_host_bitmask(arg3, fcntl_flags_tbl)));
> +
> +            unlock_user(p, arg2, sizeof(*fh) + sz);
> +        }
> +        break;
> +#endif
>      case TARGET_NR_close:
>          ret = get_errno(close(arg1));
>          break;
Paul Burton Aug. 26, 2014, 2:21 p.m. UTC | #2
On Tue, Aug 26, 2014 at 03:30:41PM +0300, Riku Voipio wrote:
> Hi Paul,
> 
> On Sun, Jun 15, 2014 at 05:18:29PM +0100, Paul Burton wrote:
> > Implement support for the name_to_handle_at and open_by_handle_at
> > syscalls, allowing their use by the target program. 
> 
> What was your testcase for these syscalls? I usually use LTP for testing
> syscalls, but there is no testcase for name_to_handle_at and
> open_by_handle_at.

Hi Riku,

First thanks for taking care of a whole bunch of these patches, and my
apologies for not being around or responsive! Meatspace has been keeping
me busy, but has calmed down for now so I should be able to find more
time to contribute :)

Actually my test for these was that a mipsel systemd could boot from
init through to a login prompt inside a container on my x86-64 host
using QEMU via binfmt_misc. That does however also require a few more
patches which I need to clean up before submitting. But you can find
them here in the short term if you're interested:

  https://github.com/Arch-Linux-MIPS/qemu

Paul

> Riku
> 
> > Signed-off-by: Paul Burton <paul@archlinuxmips.org>
> > ---
> >  linux-user/strace.c    | 30 ++++++++++++++++++++++++++++++
> >  linux-user/strace.list |  6 ++++++
> >  linux-user/syscall.c   | 50 ++++++++++++++++++++++++++++++++++++++++++++++++++
> >  3 files changed, 86 insertions(+)
> > 
> > diff --git a/linux-user/strace.c b/linux-user/strace.c
> > index ea6c1d2..c20ddf1 100644
> > --- a/linux-user/strace.c
> > +++ b/linux-user/strace.c
> > @@ -1552,6 +1552,36 @@ print_kill(const struct syscallname *name,
> >  }
> >  #endif
> >  
> > +#ifdef TARGET_NR_name_to_handle_at
> > +static void
> > +print_name_to_handle_at(const struct syscallname *name,
> > +    abi_long arg0, abi_long arg1, abi_long arg2,
> > +    abi_long arg3, abi_long arg4, abi_long arg5)
> > +{
> > +    print_syscall_prologue(name);
> > +    print_at_dirfd(arg0, 0);
> > +    print_string(arg1, 0);
> > +    print_pointer(arg2, 0);
> > +    print_pointer(arg3, 0);
> > +    print_raw_param("0x%x", arg4, 1);
> > +    print_syscall_epilogue(name);
> > +}
> > +#endif
> > +
> > +#ifdef TARGET_NR_open_by_handle_at
> > +static void
> > +print_open_by_handle_at(const struct syscallname *name,
> > +    abi_long arg0, abi_long arg1, abi_long arg2,
> > +    abi_long arg3, abi_long arg4, abi_long arg5)
> > +{
> > +    print_syscall_prologue(name);
> > +    print_raw_param("%d", arg0, 0);
> > +    print_pointer(arg2, 0);
> > +    print_open_flags(arg3, 1);
> > +    print_syscall_epilogue(name);
> > +}
> > +#endif
> > +
> >  /*
> >   * An array of all of the syscalls we know about
> >   */
> > diff --git a/linux-user/strace.list b/linux-user/strace.list
> > index 8de972a..147f579 100644
> > --- a/linux-user/strace.list
> > +++ b/linux-user/strace.list
> > @@ -582,6 +582,9 @@
> >  #ifdef TARGET_NR_munmap
> >  { TARGET_NR_munmap, "munmap" , NULL, print_munmap, NULL },
> >  #endif
> > +#ifdef TARGET_NR_name_to_handle_at
> > +{ TARGET_NR_name_to_handle_at, "name_to_handle_at" , NULL, print_name_to_handle_at, NULL },
> > +#endif
> >  #ifdef TARGET_NR_nanosleep
> >  { TARGET_NR_nanosleep, "nanosleep" , NULL, NULL, NULL },
> >  #endif
> > @@ -624,6 +627,9 @@
> >  #ifdef TARGET_NR_openat
> >  { TARGET_NR_openat, "openat" , NULL, print_openat, NULL },
> >  #endif
> > +#ifdef TARGET_NR_open_by_handle_at
> > +{ TARGET_NR_open_by_handle_at, "open_by_handle_at" , NULL, print_open_by_handle_at, NULL },
> > +#endif
> >  #ifdef TARGET_NR_osf_adjtime
> >  { TARGET_NR_osf_adjtime, "osf_adjtime" , NULL, NULL, NULL },
> >  #endif
> > diff --git a/linux-user/syscall.c b/linux-user/syscall.c
> > index c7f176a..192ad3a 100644
> > --- a/linux-user/syscall.c
> > +++ b/linux-user/syscall.c
> > @@ -5349,6 +5349,56 @@ abi_long do_syscall(void *cpu_env, int num, abi_long arg1,
> >          unlock_user(p, arg2, 0);
> >          break;
> >  #endif
> > +#ifdef TARGET_NR_name_to_handle_at
> > +    case TARGET_NR_name_to_handle_at:
> > +        {
> > +            struct file_handle *fh;
> > +            uint32_t sz;
> > +            int mount_id;
> > +
> > +            if (!(p = lock_user_string(arg2)))
> > +                goto efault;
> > +
> > +            if (get_user_u32(sz, arg3)) {
> > +                unlock_user(p, arg2, 0);
> > +                goto efault;
> > +            }
> > +
> > +            if (!(fh = lock_user(VERIFY_WRITE, arg3, sizeof(*fh) + sz, 1))) {
> > +                unlock_user(p, arg2, 0);
> > +                goto efault;
> > +            }
> > +
> > +            ret = get_errno(name_to_handle_at(arg1, path(p), fh,
> > +                                              &mount_id, arg5));
> > +
> > +            unlock_user(p, arg2, 0);
> > +            unlock_user(p, arg3, sizeof(*fh) + sz);
> > +
> > +            if (put_user_s32(mount_id, arg4))
> > +                goto efault;
> > +        }
> > +        break;
> > +#endif
> > +#ifdef TARGET_NR_open_by_handle_at
> > +    case TARGET_NR_open_by_handle_at:
> > +        {
> > +            struct file_handle *fh;
> > +            uint32_t sz;
> > +
> > +            if (get_user_u32(sz, arg2))
> > +                goto efault;
> > +
> > +            if (!(fh = lock_user(VERIFY_WRITE, arg2, sizeof(*fh) + sz, 1)))
> > +                goto efault;
> > +
> > +            ret = get_errno(open_by_handle_at(arg1, fh,
> > +                    target_to_host_bitmask(arg3, fcntl_flags_tbl)));
> > +
> > +            unlock_user(p, arg2, sizeof(*fh) + sz);
> > +        }
> > +        break;
> > +#endif
> >      case TARGET_NR_close:
> >          ret = get_errno(close(arg1));
> >          break;
Riku Voipio Aug. 28, 2014, 7:10 a.m. UTC | #3
Hi,

On Tue, Aug 26, 2014 at 03:21:30PM +0100, Paul Burton wrote:
> On Tue, Aug 26, 2014 at 03:30:41PM +0300, Riku Voipio wrote:
> > On Sun, Jun 15, 2014 at 05:18:29PM +0100, Paul Burton wrote:
> > > Implement support for the name_to_handle_at and open_by_handle_at
> > > syscalls, allowing their use by the target program. 
> > 
> > What was your testcase for these syscalls? I usually use LTP for testing
> > syscalls, but there is no testcase for name_to_handle_at and
> > open_by_handle_at.

> First thanks for taking care of a whole bunch of these patches, and my
> apologies for not being around or responsive! Meatspace has been keeping
> me busy, but has calmed down for now so I should be able to find more
> time to contribute :)

> Actually my test for these was that a mipsel systemd could boot from
> init through to a login prompt inside a container on my x86-64 host
> using QEMU via binfmt_misc. That does however also require a few more
> patches which I need to clean up before submitting. But you can find
> them here in the short term if you're interested:
 
>   https://github.com/Arch-Linux-MIPS/qemu

Ok, a good start would probably be just to rebase your changes against
current qemu head, and then send them for review - they don't need be
polished patches for first round.

Systemd booting in binfmt_misc container would be a nice additional
feature to target for the next Qemu release (2.2).

Riku

> Paul
> 
> > Riku
> > 
> > > Signed-off-by: Paul Burton <paul@archlinuxmips.org>
> > > ---
> > >  linux-user/strace.c    | 30 ++++++++++++++++++++++++++++++
> > >  linux-user/strace.list |  6 ++++++
> > >  linux-user/syscall.c   | 50 ++++++++++++++++++++++++++++++++++++++++++++++++++
> > >  3 files changed, 86 insertions(+)
> > > 
> > > diff --git a/linux-user/strace.c b/linux-user/strace.c
> > > index ea6c1d2..c20ddf1 100644
> > > --- a/linux-user/strace.c
> > > +++ b/linux-user/strace.c
> > > @@ -1552,6 +1552,36 @@ print_kill(const struct syscallname *name,
> > >  }
> > >  #endif
> > >  
> > > +#ifdef TARGET_NR_name_to_handle_at
> > > +static void
> > > +print_name_to_handle_at(const struct syscallname *name,
> > > +    abi_long arg0, abi_long arg1, abi_long arg2,
> > > +    abi_long arg3, abi_long arg4, abi_long arg5)
> > > +{
> > > +    print_syscall_prologue(name);
> > > +    print_at_dirfd(arg0, 0);
> > > +    print_string(arg1, 0);
> > > +    print_pointer(arg2, 0);
> > > +    print_pointer(arg3, 0);
> > > +    print_raw_param("0x%x", arg4, 1);
> > > +    print_syscall_epilogue(name);
> > > +}
> > > +#endif
> > > +
> > > +#ifdef TARGET_NR_open_by_handle_at
> > > +static void
> > > +print_open_by_handle_at(const struct syscallname *name,
> > > +    abi_long arg0, abi_long arg1, abi_long arg2,
> > > +    abi_long arg3, abi_long arg4, abi_long arg5)
> > > +{
> > > +    print_syscall_prologue(name);
> > > +    print_raw_param("%d", arg0, 0);
> > > +    print_pointer(arg2, 0);
> > > +    print_open_flags(arg3, 1);
> > > +    print_syscall_epilogue(name);
> > > +}
> > > +#endif
> > > +
> > >  /*
> > >   * An array of all of the syscalls we know about
> > >   */
> > > diff --git a/linux-user/strace.list b/linux-user/strace.list
> > > index 8de972a..147f579 100644
> > > --- a/linux-user/strace.list
> > > +++ b/linux-user/strace.list
> > > @@ -582,6 +582,9 @@
> > >  #ifdef TARGET_NR_munmap
> > >  { TARGET_NR_munmap, "munmap" , NULL, print_munmap, NULL },
> > >  #endif
> > > +#ifdef TARGET_NR_name_to_handle_at
> > > +{ TARGET_NR_name_to_handle_at, "name_to_handle_at" , NULL, print_name_to_handle_at, NULL },
> > > +#endif
> > >  #ifdef TARGET_NR_nanosleep
> > >  { TARGET_NR_nanosleep, "nanosleep" , NULL, NULL, NULL },
> > >  #endif
> > > @@ -624,6 +627,9 @@
> > >  #ifdef TARGET_NR_openat
> > >  { TARGET_NR_openat, "openat" , NULL, print_openat, NULL },
> > >  #endif
> > > +#ifdef TARGET_NR_open_by_handle_at
> > > +{ TARGET_NR_open_by_handle_at, "open_by_handle_at" , NULL, print_open_by_handle_at, NULL },
> > > +#endif
> > >  #ifdef TARGET_NR_osf_adjtime
> > >  { TARGET_NR_osf_adjtime, "osf_adjtime" , NULL, NULL, NULL },
> > >  #endif
> > > diff --git a/linux-user/syscall.c b/linux-user/syscall.c
> > > index c7f176a..192ad3a 100644
> > > --- a/linux-user/syscall.c
> > > +++ b/linux-user/syscall.c
> > > @@ -5349,6 +5349,56 @@ abi_long do_syscall(void *cpu_env, int num, abi_long arg1,
> > >          unlock_user(p, arg2, 0);
> > >          break;
> > >  #endif
> > > +#ifdef TARGET_NR_name_to_handle_at
> > > +    case TARGET_NR_name_to_handle_at:
> > > +        {
> > > +            struct file_handle *fh;
> > > +            uint32_t sz;
> > > +            int mount_id;
> > > +
> > > +            if (!(p = lock_user_string(arg2)))
> > > +                goto efault;
> > > +
> > > +            if (get_user_u32(sz, arg3)) {
> > > +                unlock_user(p, arg2, 0);
> > > +                goto efault;
> > > +            }
> > > +
> > > +            if (!(fh = lock_user(VERIFY_WRITE, arg3, sizeof(*fh) + sz, 1))) {
> > > +                unlock_user(p, arg2, 0);
> > > +                goto efault;
> > > +            }
> > > +
> > > +            ret = get_errno(name_to_handle_at(arg1, path(p), fh,
> > > +                                              &mount_id, arg5));
> > > +
> > > +            unlock_user(p, arg2, 0);
> > > +            unlock_user(p, arg3, sizeof(*fh) + sz);
> > > +
> > > +            if (put_user_s32(mount_id, arg4))
> > > +                goto efault;
> > > +        }
> > > +        break;
> > > +#endif
> > > +#ifdef TARGET_NR_open_by_handle_at
> > > +    case TARGET_NR_open_by_handle_at:
> > > +        {
> > > +            struct file_handle *fh;
> > > +            uint32_t sz;
> > > +
> > > +            if (get_user_u32(sz, arg2))
> > > +                goto efault;
> > > +
> > > +            if (!(fh = lock_user(VERIFY_WRITE, arg2, sizeof(*fh) + sz, 1)))
> > > +                goto efault;
> > > +
> > > +            ret = get_errno(open_by_handle_at(arg1, fh,
> > > +                    target_to_host_bitmask(arg3, fcntl_flags_tbl)));
> > > +
> > > +            unlock_user(p, arg2, sizeof(*fh) + sz);
> > > +        }
> > > +        break;
> > > +#endif
> > >      case TARGET_NR_close:
> > >          ret = get_errno(close(arg1));
> > >          break;
diff mbox

Patch

diff --git a/linux-user/strace.c b/linux-user/strace.c
index ea6c1d2..c20ddf1 100644
--- a/linux-user/strace.c
+++ b/linux-user/strace.c
@@ -1552,6 +1552,36 @@  print_kill(const struct syscallname *name,
 }
 #endif
 
+#ifdef TARGET_NR_name_to_handle_at
+static void
+print_name_to_handle_at(const struct syscallname *name,
+    abi_long arg0, abi_long arg1, abi_long arg2,
+    abi_long arg3, abi_long arg4, abi_long arg5)
+{
+    print_syscall_prologue(name);
+    print_at_dirfd(arg0, 0);
+    print_string(arg1, 0);
+    print_pointer(arg2, 0);
+    print_pointer(arg3, 0);
+    print_raw_param("0x%x", arg4, 1);
+    print_syscall_epilogue(name);
+}
+#endif
+
+#ifdef TARGET_NR_open_by_handle_at
+static void
+print_open_by_handle_at(const struct syscallname *name,
+    abi_long arg0, abi_long arg1, abi_long arg2,
+    abi_long arg3, abi_long arg4, abi_long arg5)
+{
+    print_syscall_prologue(name);
+    print_raw_param("%d", arg0, 0);
+    print_pointer(arg2, 0);
+    print_open_flags(arg3, 1);
+    print_syscall_epilogue(name);
+}
+#endif
+
 /*
  * An array of all of the syscalls we know about
  */
diff --git a/linux-user/strace.list b/linux-user/strace.list
index 8de972a..147f579 100644
--- a/linux-user/strace.list
+++ b/linux-user/strace.list
@@ -582,6 +582,9 @@ 
 #ifdef TARGET_NR_munmap
 { TARGET_NR_munmap, "munmap" , NULL, print_munmap, NULL },
 #endif
+#ifdef TARGET_NR_name_to_handle_at
+{ TARGET_NR_name_to_handle_at, "name_to_handle_at" , NULL, print_name_to_handle_at, NULL },
+#endif
 #ifdef TARGET_NR_nanosleep
 { TARGET_NR_nanosleep, "nanosleep" , NULL, NULL, NULL },
 #endif
@@ -624,6 +627,9 @@ 
 #ifdef TARGET_NR_openat
 { TARGET_NR_openat, "openat" , NULL, print_openat, NULL },
 #endif
+#ifdef TARGET_NR_open_by_handle_at
+{ TARGET_NR_open_by_handle_at, "open_by_handle_at" , NULL, print_open_by_handle_at, NULL },
+#endif
 #ifdef TARGET_NR_osf_adjtime
 { TARGET_NR_osf_adjtime, "osf_adjtime" , NULL, NULL, NULL },
 #endif
diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index c7f176a..192ad3a 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -5349,6 +5349,56 @@  abi_long do_syscall(void *cpu_env, int num, abi_long arg1,
         unlock_user(p, arg2, 0);
         break;
 #endif
+#ifdef TARGET_NR_name_to_handle_at
+    case TARGET_NR_name_to_handle_at:
+        {
+            struct file_handle *fh;
+            uint32_t sz;
+            int mount_id;
+
+            if (!(p = lock_user_string(arg2)))
+                goto efault;
+
+            if (get_user_u32(sz, arg3)) {
+                unlock_user(p, arg2, 0);
+                goto efault;
+            }
+
+            if (!(fh = lock_user(VERIFY_WRITE, arg3, sizeof(*fh) + sz, 1))) {
+                unlock_user(p, arg2, 0);
+                goto efault;
+            }
+
+            ret = get_errno(name_to_handle_at(arg1, path(p), fh,
+                                              &mount_id, arg5));
+
+            unlock_user(p, arg2, 0);
+            unlock_user(p, arg3, sizeof(*fh) + sz);
+
+            if (put_user_s32(mount_id, arg4))
+                goto efault;
+        }
+        break;
+#endif
+#ifdef TARGET_NR_open_by_handle_at
+    case TARGET_NR_open_by_handle_at:
+        {
+            struct file_handle *fh;
+            uint32_t sz;
+
+            if (get_user_u32(sz, arg2))
+                goto efault;
+
+            if (!(fh = lock_user(VERIFY_WRITE, arg2, sizeof(*fh) + sz, 1)))
+                goto efault;
+
+            ret = get_errno(open_by_handle_at(arg1, fh,
+                    target_to_host_bitmask(arg3, fcntl_flags_tbl)));
+
+            unlock_user(p, arg2, sizeof(*fh) + sz);
+        }
+        break;
+#endif
     case TARGET_NR_close:
         ret = get_errno(close(arg1));
         break;