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Re: [PATCH v3 2/4] Consolidate lseek/lseek64/llseek implementations
- From: Adhemerval Zanella <adhemerval dot zanella at linaro dot org>
- To: libc-alpha at sourceware dot org
- Date: Tue, 25 Oct 2016 15:53:47 -0200
- Subject: Re: [PATCH v3 2/4] Consolidate lseek/lseek64/llseek implementations
- Authentication-results: sourceware.org; auth=none
- References: <1474383714-15187-1-git-send-email-adhemerval.zanella@linaro.org> <1474383714-15187-3-git-send-email-adhemerval.zanella@linaro.org> <f51a1cac-ddbf-2ea1-9f1f-dee53afca110@linaro.org>
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. */
>>