This is the mail archive of the libc-alpha@sourceware.org mailing list for the glibc project.


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]
Other format: [Raw text]

Re: [PATCH v3 2/4] Consolidate lseek/lseek64/llseek implementations


Ping (x2).

On 11/10/2016 11:39, Adhemerval Zanella wrote:
> Ping.
> 
> On 20/09/2016 12:01, Adhemerval Zanella wrote:
>> Changes from previous version:
>>
>>   - lseek64 logic to define which syscall to use depends only of
>>     __NR__llseek and __NR_lseek avaliability (instead of relying on
>>     __OFF_T_MATCHES_OFF64_T).  This is make new ports that might
>>     define __OFF_T_MATCHES_OFF64_T, but still use the __NR__llseek
>>     (such as aarch64 ilp32).
>>
>>   - Add a guard while defining __NR__llseek only if __NR_llseek is
>>     also defined.
>>
>>   - Rebase for new pthread compat wrappers Makefile changes.
>>
>> --
>>
>> This patch consolidates all Linux lseek/lseek64/llseek implementation
>> in on on sysdeps/unix/sysv/linux/lseek{64}.c.  It also removes the llseek
>> file and instead consolidate the LFS lseek implementation on lseek64.c
>> as for other LFS symbols implementations.
>>
>> The general idea is:
>>
>>   - lseek: ABIs that not define __OFF_T_MATCHES_OFF64_T will preferable
>>   use __NR__llseek if kernel supports it, otherwise they will use __NR_lseek.
>>   ABIs that defines __OFF_T_MATCHES_OFF64_T won't produce any symbol.
>>
>>   - lseek64: ABIs with __OFF_T_MATCHES_OFF64_T will preferable use __NR_lseek
>>   (since it will use 64-bit arguments without low/high splitting) and
>>   __NR__llseek if __NR_lseek is not defined (for some ILP32 ports).
>>
>>   - llseek: files will be removed and symbols will be aliased ot lseek64.
>>
>> ABI without __OFF_T_MATCHES_OFF64_T and without __NR_llseek (basically MIPS64n32
>> so far) are covered by building lseek with off_t as expected and lseek64
>> using __NR_lseek (as expected for off64_t being passed using 64-bit registers).
>>
>> For this consolidation I mantained the x32 assembly specific implementation
>> because to correctly fix this it would required both the x32 fix for
>> {INLINE,INTERNAL}_SYSCALL [1] and a wrapper to correctly subscribe it to
>> return 64 bits instead of default 32 bits (as for times).  It could a future
>> cleanup.
>>
>> It is based on my previous {INTERNAL,INLINE}_SYSCALL_CALL macro [2],
>> although it is mainly for simplification.
>>
>> Tested on x86_64, i686, aarch64, armhf, and powerpc64le.
>>
>> 	* nptl/Makefile (pthread-compat-wrappers): Remove llseek and add
>> 	lseek64.
>> 	* sysdeps/unix/sysv/linux/Makefile (sysdeps_routines): Remove llseek.
>> 	* sysdeps/unix/sysv/linux/alpha/Makefile (sysdeps_routines):
>> 	Likewise.
>> 	* sysdeps/unix/sysv/linux/generic/sysdep.h (__NR__llseek): Define iff
>> 	__NR_llseek is defined.
>> 	* sysdeps/unix/sysv/linux/generic/wordsize-32/llseek.c: Remove file.
>> 	* sysdeps/unix/sysv/linux/generic/wordsize-32/lseek.c: Remove file.
>> 	* sysdeps/unix/sysv/linux/mips/mips64/llseek.c: Likewise.
>> 	* sysdeps/unix/sysv/linux/llseek.c: Remove file.
>> 	* sysdeps/unix/sysv/linux/lseek.c: New file.
>> 	* sysdeps/unix/sysv/linux/lseek64.c: Add default Linux implementation.
>> 	* sysdeps/unix/sysv/linux/mips/mips64/syscalls.list: Remove lseek and
>> 	__libc_lseek64 from auto-generation.
>> 	* sysdeps/unix/sysv/linux/wordsize-64/syscalls.list: Likewise.
>> 	* sysdeps/unix/sysv/linux/x86_64/x32/lseek64.S: New file.
>>
>> [1] https://sourceware.org/ml/libc-alpha/2016-08/msg00443.html
>> [2] https://sourceware.org/ml/libc-alpha/2016-08/msg00646.html
>> ---
>>  nptl/Makefile                                      |  2 +-
>>  sysdeps/unix/sysv/linux/Makefile                   |  2 +-
>>  sysdeps/unix/sysv/linux/alpha/Makefile             |  2 +-
>>  sysdeps/unix/sysv/linux/generic/sysdep.h           |  4 +-
>>  .../unix/sysv/linux/generic/wordsize-32/llseek.c   | 46 ------------------
>>  .../unix/sysv/linux/generic/wordsize-32/lseek.c    | 38 ---------------
>>  sysdeps/unix/sysv/linux/llseek.c                   | 46 ------------------
>>  sysdeps/unix/sysv/linux/lseek.c                    | 56 ++++++++++++++++++++++
>>  sysdeps/unix/sysv/linux/lseek64.c                  | 54 ++++++++++++++++++++-
>>  sysdeps/unix/sysv/linux/mips/mips64/llseek.c       |  1 -
>>  sysdeps/unix/sysv/linux/mips/mips64/syscalls.list  |  2 -
>>  sysdeps/unix/sysv/linux/wordsize-64/syscalls.list  |  3 --
>>  sysdeps/unix/sysv/linux/x86_64/x32/lseek64.S       |  1 +
>>  13 files changed, 116 insertions(+), 141 deletions(-)
>>  delete mode 100644 sysdeps/unix/sysv/linux/generic/wordsize-32/llseek.c
>>  delete mode 100644 sysdeps/unix/sysv/linux/generic/wordsize-32/lseek.c
>>  delete mode 100644 sysdeps/unix/sysv/linux/llseek.c
>>  create mode 100644 sysdeps/unix/sysv/linux/lseek.c
>>  delete mode 100644 sysdeps/unix/sysv/linux/mips/mips64/llseek.c
>>  create mode 100644 sysdeps/unix/sysv/linux/x86_64/x32/lseek64.S
>>
>> diff --git a/nptl/Makefile b/nptl/Makefile
>> index e9485df..ee828fe 100644
>> --- a/nptl/Makefile
>> +++ b/nptl/Makefile
>> @@ -38,7 +38,7 @@ shared-only-routines = forward
>>  pthread-compat-wrappers = \
>>  		      write read close fcntl accept \
>>  		      connect recv recvfrom send \
>> -		      sendto fsync lseek llseek \
>> +		      sendto fsync lseek lseek64 \
>>  		      msync nanosleep open open64 pause \
>>  		      pread pread64 pwrite pwrite64 \
>>  		      tcdrain wait waitpid msgrcv msgsnd \
>> diff --git a/sysdeps/unix/sysv/linux/Makefile b/sysdeps/unix/sysv/linux/Makefile
>> index 9a0423e..16a61cb 100644
>> --- a/sysdeps/unix/sysv/linux/Makefile
>> +++ b/sysdeps/unix/sysv/linux/Makefile
>> @@ -14,7 +14,7 @@ endif
>>  ifeq ($(subdir),misc)
>>  include $(firstword $(wildcard $(sysdirs:=/sysctl.mk)))
>>  
>> -sysdep_routines += clone llseek umount umount2 readahead \
>> +sysdep_routines += clone umount umount2 readahead \
>>  		   setfsuid setfsgid epoll_pwait signalfd \
>>  		   eventfd eventfd_read eventfd_write prlimit \
>>  		   personality
>> diff --git a/sysdeps/unix/sysv/linux/alpha/Makefile b/sysdeps/unix/sysv/linux/alpha/Makefile
>> index 1e858ce..45941b0 100644
>> --- a/sysdeps/unix/sysv/linux/alpha/Makefile
>> +++ b/sysdeps/unix/sysv/linux/alpha/Makefile
>> @@ -10,7 +10,7 @@ ifeq ($(subdir),misc)
>>  sysdep_headers += alpha/ptrace.h alpha/regdef.h sys/io.h
>>  
>>  sysdep_routines += ieee_get_fp_control ieee_set_fp_control \
>> -		   ioperm llseek
>> +		   ioperm
>>  
>>  # Support old timeval32 entry points
>>  sysdep_routines += osf_select osf_gettimeofday osf_settimeofday \
>> diff --git a/sysdeps/unix/sysv/linux/generic/sysdep.h b/sysdeps/unix/sysv/linux/generic/sysdep.h
>> index b0422ff..6d379cc 100644
>> --- a/sysdeps/unix/sysv/linux/generic/sysdep.h
>> +++ b/sysdeps/unix/sysv/linux/generic/sysdep.h
>> @@ -22,7 +22,9 @@
>>  #include <sysdeps/unix/sysv/linux/sysdep.h>
>>  
>>  /* Provide the common name to allow more code reuse.  */
>> -#define __NR__llseek __NR_llseek
>> +#ifdef __NR_llseek
>> +# define __NR__llseek __NR_llseek
>> +#endif
>>  
>>  #if __WORDSIZE == 64
>>  /* By defining the older names, glibc will build syscall wrappers for
>> diff --git a/sysdeps/unix/sysv/linux/generic/wordsize-32/llseek.c b/sysdeps/unix/sysv/linux/generic/wordsize-32/llseek.c
>> deleted file mode 100644
>> index 458964c..0000000
>> --- a/sysdeps/unix/sysv/linux/generic/wordsize-32/llseek.c
>> +++ /dev/null
>> @@ -1,46 +0,0 @@
>> -/* Copyright (C) 2011-2016 Free Software Foundation, Inc.
>> -   This file is part of the GNU C Library.
>> -   Contributed by Chris Metcalf <cmetcalf@tilera.com>, 2011.
>> -
>> -   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
>> -   <http://www.gnu.org/licenses/>.  */
>> -
>> -#include <errno.h>
>> -#include <sys/types.h>
>> -
>> -#include <sysdep.h>
>> -#include <sys/syscall.h>
>> -
>> -/* Seek to OFFSET on FD, starting from WHENCE.  */
>> -extern loff_t __llseek (int fd, loff_t offset, int whence);
>> -
>> -loff_t
>> -__llseek (int fd, loff_t offset, int whence)
>> -{
>> -  loff_t retval;
>> -
>> -  return (loff_t) (INLINE_SYSCALL (_llseek, 5, fd, (off_t) (offset >> 32),
>> -				   (off_t) (offset & 0xffffffff),
>> -				   &retval, whence) ?: retval);
>> -}
>> -weak_alias (__llseek, llseek)
>> -strong_alias (__llseek, __libc_lseek64)
>> -strong_alias (__llseek, __lseek64)
>> -weak_alias (__llseek, lseek64)
>> -
>> -/* llseek doesn't have a prototype.  Since the second parameter is a
>> -   64bit type, this results in wrong behaviour if no prototype is
>> -   provided.  */
>> -link_warning (llseek, "\
>> -the `llseek' function may be dangerous; use `lseek64' instead.")
>> diff --git a/sysdeps/unix/sysv/linux/generic/wordsize-32/lseek.c b/sysdeps/unix/sysv/linux/generic/wordsize-32/lseek.c
>> deleted file mode 100644
>> index dbf0b26..0000000
>> --- a/sysdeps/unix/sysv/linux/generic/wordsize-32/lseek.c
>> +++ /dev/null
>> @@ -1,38 +0,0 @@
>> -/* Copyright (C) 2011-2016 Free Software Foundation, Inc.
>> -   This file is part of the GNU C Library.
>> -   Contributed by Chris Metcalf <cmetcalf@tilera.com>, 2011.
>> -
>> -   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
>> -   <http://www.gnu.org/licenses/>.  */
>> -
>> -#include <errno.h>
>> -#include <unistd.h>
>> -#include <sys/types.h>
>> -
>> -#include <sysdep.h>
>> -#include <sys/syscall.h>
>> -
>> -#include "overflow.h"
>> -
>> -off_t
>> -__lseek (int fd, off_t offset, int whence)
>> -{
>> -  loff_t res;
>> -  int rc = INLINE_SYSCALL (_llseek, 5, fd, (off_t) (offset >> 31),
>> -                           (off_t) offset, &res, whence);
>> -  return rc ?: lseek_overflow (res);
>> -}
>> -libc_hidden_def (__lseek)
>> -weak_alias (__lseek, lseek)
>> -strong_alias (__lseek, __libc_lseek)
>> diff --git a/sysdeps/unix/sysv/linux/llseek.c b/sysdeps/unix/sysv/linux/llseek.c
>> deleted file mode 100644
>> index b6f3ea5..0000000
>> --- a/sysdeps/unix/sysv/linux/llseek.c
>> +++ /dev/null
>> @@ -1,46 +0,0 @@
>> -/* Long-long seek operation.
>> -   Copyright (C) 1996-2016 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
>> -   <http://www.gnu.org/licenses/>.  */
>> -
>> -#include <errno.h>
>> -#include <sys/types.h>
>> -
>> -#include <sysdep.h>
>> -#include <sys/syscall.h>
>> -
>> -/* Seek to OFFSET on FD, starting from WHENCE.  */
>> -extern loff_t __llseek (int fd, loff_t offset, int whence);
>> -
>> -loff_t
>> -__llseek (int fd, loff_t offset, int whence)
>> -{
>> -  loff_t retval;
>> -
>> -  return (loff_t) (INLINE_SYSCALL (_llseek, 5, fd, (off_t) (offset >> 32),
>> -				   (off_t) (offset & 0xffffffff),
>> -				   &retval, whence) ?: retval);
>> -}
>> -weak_alias (__llseek, llseek)
>> -strong_alias (__llseek, __libc_lseek64)
>> -strong_alias (__llseek, __lseek64)
>> -weak_alias (__llseek, lseek64)
>> -
>> -/* llseek doesn't have a prototype.  Since the second parameter is a
>> -   64bit type, this results in wrong behaviour if no prototype is
>> -   provided.  */
>> -link_warning (llseek, "\
>> -the `llseek' function may be dangerous; use `lseek64' instead.")
>> diff --git a/sysdeps/unix/sysv/linux/lseek.c b/sysdeps/unix/sysv/linux/lseek.c
>> new file mode 100644
>> index 0000000..568df01
>> --- /dev/null
>> +++ b/sysdeps/unix/sysv/linux/lseek.c
>> @@ -0,0 +1,56 @@
>> +/* Copyright (C) 2016 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
>> +   <http://www.gnu.org/licenses/>.  */
>> +
>> +#include <unistd.h>
>> +#include <stdint.h>
>> +#include <sys/types.h>
>> +#include <sysdep.h>
>> +#include <errno.h>
>> +
>> +#ifndef __OFF_T_MATCHES_OFF64_T
>> +
>> +/* Test for overflows of structures where we ask the kernel to fill them
>> +   in with standard 64-bit syscalls but return them through APIs that
>> +   only expose the low 32 bits of some fields.  */
>> +
>> +static inline off_t lseek_overflow (loff_t res)
>> +{
>> +  off_t retval = (off_t) res;
>> +  if (retval == res)
>> +    return retval;
>> +
>> +  __set_errno (EOVERFLOW);
>> +  return (off_t) -1;
>> +}
>> +
>> +off_t
>> +__lseek (int fd, off_t offset, int whence)
>> +{
>> +# ifdef __NR__llseek
>> +  loff_t res;
>> +  int rc = INLINE_SYSCALL_CALL (_llseek, fd,
>> +				(long) (((uint64_t) (offset)) >> 32),
>> +				(long) offset, &res, whence);
>> +  return rc ?: lseek_overflow (res);
>> +# else
>> +  return INLINE_SYSCALL_CALL (lseek, fd, offset, whence);
>> +# endif
>> +}
>> +libc_hidden_def (__lseek)
>> +weak_alias (__lseek, lseek)
>> +strong_alias (__lseek, __libc_lseek)
>> +#endif /* __OFF_T_MATCHES_OFF64_T  */
>> diff --git a/sysdeps/unix/sysv/linux/lseek64.c b/sysdeps/unix/sysv/linux/lseek64.c
>> index d81e98f..7e1ff23 100644
>> --- a/sysdeps/unix/sysv/linux/lseek64.c
>> +++ b/sysdeps/unix/sysv/linux/lseek64.c
>> @@ -1 +1,53 @@
>> -/* We don't need a definition since the llseek function is what we need.  */
>> +/* Copyright (C) 2016 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
>> +   <http://www.gnu.org/licenses/>.  */
>> +
>> +#include <unistd.h>
>> +#include <stdint.h>
>> +#include <sys/types.h>
>> +#include <sysdep.h>
>> +#include <errno.h>
>> +
>> +off64_t
>> +__lseek64 (int fd, off64_t offset, int whence)
>> +{
>> +#ifdef __NR__llseek
>> +  loff_t res;
>> +  int rc = INLINE_SYSCALL_CALL (_llseek, fd,
>> +				(long) (((uint64_t) (offset)) >> 32),
>> +				(long) offset, &res, whence);
>> +  return rc ?: res;
>> +#else
>> +  return INLINE_SYSCALL_CALL (lseek, fd, offset, whence);
>> +#endif
>> +}
>> +
>> +#ifdef  __OFF_T_MATCHES_OFF64_T
>> +weak_alias (__lseek64, lseek)
>> +weak_alias (__lseek64, __lseek)
>> +strong_alias (__lseek64, __libc_lseek)
>> +libc_hidden_def (__lseek)
>> +#endif
>> +
>> +strong_alias (__lseek64, __libc_lseek64)
>> +weak_alias (__lseek64, lseek64)
>> +
>> +/* llseek doesn't have a prototype.  Since the second parameter is a
>> +   64bit type, this results in wrong behaviour if no prototype is
>> +   provided.  */
>> +weak_alias (__lseek64, llseek)
>> +link_warning (llseek, "\
>> +the `llseek' function may be dangerous; use `lseek64' instead.")
>> diff --git a/sysdeps/unix/sysv/linux/mips/mips64/llseek.c b/sysdeps/unix/sysv/linux/mips/mips64/llseek.c
>> deleted file mode 100644
>> index 24013a8..0000000
>> --- a/sysdeps/unix/sysv/linux/mips/mips64/llseek.c
>> +++ /dev/null
>> @@ -1 +0,0 @@
>> -/* lseek() is 64-bit capable already.  */
>> diff --git a/sysdeps/unix/sysv/linux/mips/mips64/syscalls.list b/sysdeps/unix/sysv/linux/mips/mips64/syscalls.list
>> index 66cc687..d2d851e 100644
>> --- a/sysdeps/unix/sysv/linux/mips/mips64/syscalls.list
>> +++ b/sysdeps/unix/sysv/linux/mips/mips64/syscalls.list
>> @@ -1,7 +1,5 @@
>>  # File name	Caller	Syscall name	Args	Strong name	Weak names
>>  
>> -lseek		-	lseek		i:iii	__libc_lseek	__lseek lseek __llseek llseek __libc_lseek64 __lseek64 lseek64
>> -
>>  ftruncate	-	ftruncate	i:ii	__ftruncate	ftruncate ftruncate64 __ftruncate64
>>  truncate	-	truncate	i:si	truncate	truncate64
>>  
>> diff --git a/sysdeps/unix/sysv/linux/wordsize-64/syscalls.list b/sysdeps/unix/sysv/linux/wordsize-64/syscalls.list
>> index 2eb9419..3f3569f 100644
>> --- a/sysdeps/unix/sysv/linux/wordsize-64/syscalls.list
>> +++ b/sysdeps/unix/sysv/linux/wordsize-64/syscalls.list
>> @@ -1,8 +1,5 @@
>>  # File name	Caller	Syscall name	# args	Strong name	Weak names
>>  
>> -# Whee! 64-bit systems naturally implement llseek.
>> -llseek		EXTRA	lseek		i:iii	__libc_lseek	__lseek lseek __libc_lseek64 __llseek llseek __lseek64 lseek64
>> -lseek		llseek	-
>>  fstatfs		-	fstatfs		i:ip	__fstatfs	fstatfs fstatfs64 __fstatfs64
>>  statfs		-	statfs		i:sp	__statfs	statfs statfs64
>>  mmap		-	mmap		b:aniiii __mmap		mmap __mmap64 mmap64
>> diff --git a/sysdeps/unix/sysv/linux/x86_64/x32/lseek64.S b/sysdeps/unix/sysv/linux/x86_64/x32/lseek64.S
>> new file mode 100644
>> index 0000000..d81e98f
>> --- /dev/null
>> +++ b/sysdeps/unix/sysv/linux/x86_64/x32/lseek64.S
>> @@ -0,0 +1 @@
>> +/* We don't need a definition since the llseek function is what we need.  */
>>


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]