[16/16] linux: Move xmknoda{at} to compat symbols

  It also decouple mknod{at} from xmknod{at}.

Checked with a build for all affected Linux ABIs.  I checked also
on x86_64-linux-gnu and i686-linux-gnu.
---
 include/sys/stat.h                 |  6 +++--
 sysdeps/mach/hurd/xmknod.c         |  1 -
 sysdeps/mach/hurd/xmknodat.c       |  2 --
 sysdeps/unix/sysv/linux/mknod.c    | 28 ++++++++++++++++++++
 sysdeps/unix/sysv/linux/mknodat.c  | 41 ++++++++++++++++++++++++++++++
 sysdeps/unix/sysv/linux/xmknod.c   | 20 +++++----------
 sysdeps/unix/sysv/linux/xmknodat.c | 23 +++++------------
 7 files changed, 86 insertions(+), 35 deletions(-)
 create mode 100644 sysdeps/unix/sysv/linux/mknod.c
 create mode 100644 sysdeps/unix/sysv/linux/mknodat.c
  

* Adhemerval Zanella via Libc-alpha:

> diff --git a/sysdeps/unix/sysv/linux/mknodat.c b/sysdeps/unix/sysv/linux/mknodat.c
> new file mode 100644
> index 0000000000..d160fe520b
> --- /dev/null
> +++ b/sysdeps/unix/sysv/linux/mknodat.c
> @@ -0,0 +1,41 @@

> +int
> +__mknodat_common (int fd, const char *path, mode_t mode, dev_t *dev)
> +{
> +  /* We must convert the value to dev_t type used by the kernel.  */
> +  unsigned long long int k_dev = (*dev) & ((1ULL << 32) - 1);
> +  if (k_dev != *dev)
> +    return INLINE_SYSCALL_ERROR_RETURN_VALUE (EINVAL);
> +
> +  return INLINE_SYSCALL_CALL (mknodat, fd, path, mode,
> +			      (unsigned int) k_dev);
> +}

This looks suspicious yo me.  Why use a dev_t * argument?  Why check
against the unsigned long long int value, when the kernel receives an
unsigned int value in the system call?

What's the intended difference between __mknodat_common and __mknodat?

Thanks,
Florian
  

On Thu, 23 Jul 2020 16:46:41 -0300
Adhemerval Zanella <adhemerval.zanella@linaro.org> wrote:

> It also decouple mknod{at} from xmknod{at}.
> 
> Checked with a build for all affected Linux ABIs.  I checked also
> on x86_64-linux-gnu and i686-linux-gnu.

Reviewed-by: Lukasz Majewski <lukma@denx.de>

> ---
>  include/sys/stat.h                 |  6 +++--
>  sysdeps/mach/hurd/xmknod.c         |  1 -
>  sysdeps/mach/hurd/xmknodat.c       |  2 --
>  sysdeps/unix/sysv/linux/mknod.c    | 28 ++++++++++++++++++++
>  sysdeps/unix/sysv/linux/mknodat.c  | 41
> ++++++++++++++++++++++++++++++ sysdeps/unix/sysv/linux/xmknod.c   |
> 20 +++++---------- sysdeps/unix/sysv/linux/xmknodat.c | 23
> +++++------------ 7 files changed, 86 insertions(+), 35 deletions(-)
>  create mode 100644 sysdeps/unix/sysv/linux/mknod.c
>  create mode 100644 sysdeps/unix/sysv/linux/mknodat.c
> 
> diff --git a/include/sys/stat.h b/include/sys/stat.h
> index 87d4a5ec4f..da8b14fee0 100644
> --- a/include/sys/stat.h
> +++ b/include/sys/stat.h
> @@ -84,6 +84,8 @@ extern __mode_t __umask (__mode_t __mask);
>  extern int __mkdir (const char *__path, __mode_t __mode);
>  libc_hidden_proto (__mkdir)
>  
> +extern int __mknodat_common (int fd, const char *, __mode_t, __dev_t
> *)
> +  attribute_hidden;
>  extern int __mknodat (int fd, const char *path, mode_t mode, dev_t
> dev); libc_hidden_proto (__mknodat);
>  extern int __mknod (const char *__path,
> @@ -92,10 +94,8 @@ libc_hidden_proto (__mknod);
>  
>  extern int __xmknod (int __ver, const char *__path, __mode_t __mode,
>  		     __dev_t *__dev);
> -libc_hidden_proto (__xmknod)
>  extern int __xmknodat (int __ver, int __fd, const char *__path,
>  		       __mode_t __mode, __dev_t *__dev);
> -libc_hidden_proto (__xmknodat)
>  
>  int __fxstat (int __ver, int __fildes, struct stat *__stat_buf);
>  int __xstat (int __ver, const char *__filename,
> @@ -121,6 +121,8 @@ hidden_proto (__xstat64);
>  hidden_proto (__lxstat64);
>  hidden_proto (__fxstatat64);
>  #  endif
> +libc_hidden_proto (__xmknod)
> +libc_hidden_proto (__xmknodat)
>  #  define stat(fname, buf) __xstat (_STAT_VER, fname, buf)
>  #  define lstat(fname, buf)  __lxstat (_STAT_VER, fname, buf)
>  #  define __lstat(fname, buf)  __lxstat (_STAT_VER, fname, buf)
> diff --git a/sysdeps/mach/hurd/xmknod.c b/sysdeps/mach/hurd/xmknod.c
> index 0ab4f1b719..67e32f518d 100644
> --- a/sysdeps/mach/hurd/xmknod.c
> +++ b/sysdeps/mach/hurd/xmknod.c
> @@ -30,4 +30,3 @@ __xmknod (int vers, const char *file_name, mode_t
> mode, dev_t *dev) {
>    return __xmknodat (vers, AT_FDCWD, file_name, mode, dev);
>  }
> -libc_hidden_def (__xmknod)
> diff --git a/sysdeps/mach/hurd/xmknodat.c
> b/sysdeps/mach/hurd/xmknodat.c index 4239d1ea91..0333765ebc 100644
> --- a/sysdeps/mach/hurd/xmknodat.c
> +++ b/sysdeps/mach/hurd/xmknodat.c
> @@ -116,5 +116,3 @@ __xmknodat (int vers, int fd, const char *path,
> mode_t mode, dev_t *dev) return __hurd_fail (err);
>    return 0;
>  }
> -
> -libc_hidden_def (__xmknodat)
> diff --git a/sysdeps/unix/sysv/linux/mknod.c
> b/sysdeps/unix/sysv/linux/mknod.c new file mode 100644
> index 0000000000..3185726f52
> --- /dev/null
> +++ b/sysdeps/unix/sysv/linux/mknod.c
> @@ -0,0 +1,28 @@
> +/* Create a special or ordinary file.  Linux version.
> +   Copyright (C) 2020 Free Software Foundation, Inc.
> +   This file is part of the GNU C Library.
> +
> +   The GNU C Library is free software; you can redistribute it and/or
> +   modify it under the terms of the GNU Lesser General Public
> +   License as published by the Free Software Foundation; either
> +   version 2.1 of the License, or (at your option) any later version.
> +
> +   The GNU C Library is distributed in the hope that it will be
> useful,
> +   but WITHOUT ANY WARRANTY; without even the implied warranty of
> +   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
> +   Lesser General Public License for more details.
> +
> +   You should have received a copy of the GNU Lesser General Public
> +   License along with the GNU C Library; if not, see
> +   <https://www.gnu.org/licenses/>.  */
> +
> +#include <sys/stat.h>
> +#include <fcntl.h>
> +
> +int
> +__mknod (const char *path, mode_t mode, dev_t dev)
> +{
> +  return __mknodat_common (AT_FDCWD, path, mode, &dev);
> +}
> +libc_hidden_def (__mknod)
> +weak_alias (__mknod, mknod)
> diff --git a/sysdeps/unix/sysv/linux/mknodat.c
> b/sysdeps/unix/sysv/linux/mknodat.c new file mode 100644
> index 0000000000..d160fe520b
> --- /dev/null
> +++ b/sysdeps/unix/sysv/linux/mknodat.c
> @@ -0,0 +1,41 @@
> +/* Create a special or ordinary file.  Linux version.
> +   Copyright (C) 2020 Free Software Foundation, Inc.
> +   This file is part of the GNU C Library.
> +
> +   The GNU C Library is free software; you can redistribute it and/or
> +   modify it under the terms of the GNU Lesser General Public
> +   License as published by the Free Software Foundation; either
> +   version 2.1 of the License, or (at your option) any later version.
> +
> +   The GNU C Library is distributed in the hope that it will be
> useful,
> +   but WITHOUT ANY WARRANTY; without even the implied warranty of
> +   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
> +   Lesser General Public License for more details.
> +
> +   You should have received a copy of the GNU Lesser General Public
> +   License along with the GNU C Library; if not, see
> +   <https://www.gnu.org/licenses/>.  */
> +
> +#include <sys/types.h>
> +#include <sys/stat.h>
> +#include <errno.h>
> +
> +int
> +__mknodat_common (int fd, const char *path, mode_t mode, dev_t *dev)
> +{
> +  /* We must convert the value to dev_t type used by the kernel.  */
> +  unsigned long long int k_dev = (*dev) & ((1ULL << 32) - 1);
> +  if (k_dev != *dev)
> +    return INLINE_SYSCALL_ERROR_RETURN_VALUE (EINVAL);
> +
> +  return INLINE_SYSCALL_CALL (mknodat, fd, path, mode,
> +			      (unsigned int) k_dev);
> +}
> +
> +int
> +__mknodat (int fd, const char *path, mode_t mode, dev_t dev)
> +{
> +  return __mknodat_common (fd, path, mode, &dev);
> +}
> +libc_hidden_def (__mknodat)
> +weak_alias (__mknodat, mknodat)
> diff --git a/sysdeps/unix/sysv/linux/xmknod.c
> b/sysdeps/unix/sysv/linux/xmknod.c index 42809d4c57..2ae384a536 100644
> --- a/sysdeps/unix/sysv/linux/xmknod.c
> +++ b/sysdeps/unix/sysv/linux/xmknod.c
> @@ -17,29 +17,23 @@
>     <https://www.gnu.org/licenses/>.  */
>  
>  #include <sys/stat.h>
> -#include <sys/sysmacros.h>
>  #include <fcntl.h>
> -#include <sysdep.h>
> +#include <errno.h>
> +#include <shlib-compat.h>
>  
> +#if SHLIB_COMPAT(libc, GLIBC_2_0, GLIBC_2_33)
>  /* Create a device file named PATH, with permission and special bits
> MODE and device number DEV (which can be constructed from major and
> minor device numbers with the `makedev' macro above).  */
>  int
> +attribute_compat_text_section
>  __xmknod (int vers, const char *path, mode_t mode, dev_t *dev)
>  {
> -  unsigned long long int k_dev;
> -
>    if (vers != _MKNOD_VER)
>      return INLINE_SYSCALL_ERROR_RETURN_VALUE (EINVAL);
>  
> -  /* We must convert the value to dev_t type used by the kernel.  */
> -  k_dev =  (*dev) & ((1ULL << 32) - 1);
> -  if (k_dev != *dev)
> -    return INLINE_SYSCALL_ERROR_RETURN_VALUE (EINVAL);
> -
> -  return INLINE_SYSCALL_CALL (mknodat, AT_FDCWD, path, mode,
> -			      (unsigned int) k_dev);
> +  return __mknodat_common (AT_FDCWD, path, mode, dev);
>  }
>  
> -weak_alias (__xmknod, _xmknod)
> -libc_hidden_def (__xmknod)
> +compat_symbol (libc, __xmknod, __xmknod, GLIBC_2_0);
> +#endif
> diff --git a/sysdeps/unix/sysv/linux/xmknodat.c
> b/sysdeps/unix/sysv/linux/xmknodat.c index 5640a499aa..11b52a29b2
> 100644 --- a/sysdeps/unix/sysv/linux/xmknodat.c
> +++ b/sysdeps/unix/sysv/linux/xmknodat.c
> @@ -15,18 +15,11 @@
>     License along with the GNU C Library; if not, see
>     <https://www.gnu.org/licenses/>.  */
>  
> -#include <errno.h>
> -#include <fcntl.h>
> -#include <stdio.h>
> -#include <string.h>
> -#include <sys/types.h>
>  #include <sys/stat.h>
> -#include <sys/sysmacros.h>
> -
> -#include <sysdep.h>
> -#include <sys/syscall.h>
> -
> +#include <errno.h>
> +#include <shlib-compat.h>
>  
> +#if SHLIB_COMPAT(libc, GLIBC_2_4, GLIBC_2_33)
>  /* Create a device file named PATH relative to FD, with permission
> and special bits MODE and device number DEV (which can be constructed
>     from major and minor device numbers with the `makedev' macro
> above).  */ @@ -36,12 +29,8 @@ __xmknodat (int vers, int fd, const
> char *file, mode_t mode, dev_t *dev) if (vers != _MKNOD_VER)
>      return INLINE_SYSCALL_ERROR_RETURN_VALUE (EINVAL);
>  
> -  /* We must convert the value to dev_t type used by the kernel.  */
> -  unsigned long long int k_dev =  (*dev) & ((1ULL << 32) - 1);
> -  if (k_dev != *dev)
> -    return INLINE_SYSCALL_ERROR_RETURN_VALUE (EINVAL);
> -
> -  return INLINE_SYSCALL (mknodat, 4, fd, file, mode, (unsigned int)
> k_dev);
> +  return __mknodat_common (fd, file, mode, dev);
>  }
>  
> -libc_hidden_def (__xmknodat)
> +compat_symbol (libc, __xmknodat, __xmknodat, GLIBC_2_4);
> +#endif




Best regards,

Lukasz Majewski

--

DENX Software Engineering GmbH,      Managing Director: Wolfgang Denk
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-59 Fax: (+49)-8142-66989-80 Email: lukma@denx.de
  

On 24/07/2020 07:30, Florian Weimer wrote:
> * Adhemerval Zanella via Libc-alpha:
> 
>> diff --git a/sysdeps/unix/sysv/linux/mknodat.c b/sysdeps/unix/sysv/linux/mknodat.c
>> new file mode 100644
>> index 0000000000..d160fe520b
>> --- /dev/null
>> +++ b/sysdeps/unix/sysv/linux/mknodat.c
>> @@ -0,0 +1,41 @@
> 
>> +int
>> +__mknodat_common (int fd, const char *path, mode_t mode, dev_t *dev)
>> +{
>> +  /* We must convert the value to dev_t type used by the kernel.  */
>> +  unsigned long long int k_dev = (*dev) & ((1ULL << 32) - 1);
>> +  if (k_dev != *dev)
>> +    return INLINE_SYSCALL_ERROR_RETURN_VALUE (EINVAL);
>> +
>> +  return INLINE_SYSCALL_CALL (mknodat, fd, path, mode,
>> +			      (unsigned int) k_dev);
>> +}
> 
> This looks suspicious yo me.  Why use a dev_t * argument?  Why check
> against the unsigned long long int value, when the kernel receives an
> unsigned int value in the system call?

Because glibc exports dev_t is 64-bit on all architectures (__DEV_T_TYPE),
while kernel current only accepts 32-bits.  But I used the dev_t *
argument to make it more straightforward to implement xmknod{at}.  I 
can change to use a dev_t as well

> 
> What's the intended difference between __mknodat_common and __mknodat
None, in fact I think it would be better to implement xmknod{at} in terms
of mknod{at}.
  

* Adhemerval Zanella:

> On 24/07/2020 07:30, Florian Weimer wrote:
>> * Adhemerval Zanella via Libc-alpha:
>> 
>>> diff --git a/sysdeps/unix/sysv/linux/mknodat.c b/sysdeps/unix/sysv/linux/mknodat.c
>>> new file mode 100644
>>> index 0000000000..d160fe520b
>>> --- /dev/null
>>> +++ b/sysdeps/unix/sysv/linux/mknodat.c
>>> @@ -0,0 +1,41 @@
>> 
>>> +int
>>> +__mknodat_common (int fd, const char *path, mode_t mode, dev_t *dev)
>>> +{
>>> +  /* We must convert the value to dev_t type used by the kernel.  */
>>> +  unsigned long long int k_dev = (*dev) & ((1ULL << 32) - 1);
>>> +  if (k_dev != *dev)
>>> +    return INLINE_SYSCALL_ERROR_RETURN_VALUE (EINVAL);
>>> +
>>> +  return INLINE_SYSCALL_CALL (mknodat, fd, path, mode,
>>> +			      (unsigned int) k_dev);
>>> +}
>> 
>> This looks suspicious yo me.  Why use a dev_t * argument?  Why check
>> against the unsigned long long int value, when the kernel receives an
>> unsigned int value in the system call?
>
> Because glibc exports dev_t is 64-bit on all architectures (__DEV_T_TYPE),
> while kernel current only accepts 32-bits.

But then the type of k_dev should be unsigned int, I think.

> But I used the dev_t * argument to make it more straightforward to
> implement xmknod{at}.  I can change to use a dev_t as well

Yes please.

Thanks,
Florian
  

On 24/07/2020 09:43, Florian Weimer wrote:
> * Adhemerval Zanella:
> 
>> On 24/07/2020 07:30, Florian Weimer wrote:
>>> * Adhemerval Zanella via Libc-alpha:
>>>
>>>> diff --git a/sysdeps/unix/sysv/linux/mknodat.c b/sysdeps/unix/sysv/linux/mknodat.c
>>>> new file mode 100644
>>>> index 0000000000..d160fe520b
>>>> --- /dev/null
>>>> +++ b/sysdeps/unix/sysv/linux/mknodat.c
>>>> @@ -0,0 +1,41 @@
>>>
>>>> +int
>>>> +__mknodat_common (int fd, const char *path, mode_t mode, dev_t *dev)
>>>> +{
>>>> +  /* We must convert the value to dev_t type used by the kernel.  */
>>>> +  unsigned long long int k_dev = (*dev) & ((1ULL << 32) - 1);
>>>> +  if (k_dev != *dev)
>>>> +    return INLINE_SYSCALL_ERROR_RETURN_VALUE (EINVAL);
>>>> +
>>>> +  return INLINE_SYSCALL_CALL (mknodat, fd, path, mode,
>>>> +			      (unsigned int) k_dev);
>>>> +}
>>>
>>> This looks suspicious yo me.  Why use a dev_t * argument?  Why check
>>> against the unsigned long long int value, when the kernel receives an
>>> unsigned int value in the system call?
>>
>> Because glibc exports dev_t is 64-bit on all architectures (__DEV_T_TYPE),
>> while kernel current only accepts 32-bits.
> 
> But then the type of k_dev should be unsigned int, I think.

Indeed, the code at least does it on the INLINE_SYSCALL_CALL. I copied the 
code as is from current linux xmknodat, but I agree with you that it is
not the most clear one.

> 
>> But I used the dev_t * argument to make it more straightforward to
>> implement xmknod{at}.  I can change to use a dev_t as well
> 
> Yes please.

Ack.