[v2] io: Refactor close_range and closefrom
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Commit Message
Now that Hurd implementis both close_range and closefrom (f2c996597d),
we can make close_range() a base ABI, and make the default closefrom()
implementation on top of close_range().
The generic closefrom() implementation based on __getdtablesize() is
moved to generic close_range(). On Linux it will be overriden by
the auto-generation syscall while on Hurd it will be a system specific
implementation.
The closefrom() now calls close_range() and __closefrom_fallback().
Since on Hurd close_range() does not fail, __closefrom_fallback() is an
empty static inline function set by__ASSUME_CLOSE_RANGE.
The __ASSUME_CLOSE_RANGE also allows optimize Linux
__closefrom_fallback() implementation when --enable-kernel=5.9 or
higher is used.
Finally the Linux specific tst-close_range.c is moved to io and
enabled as default. The Linuxism and CLOSE_RANGE_UNSHARE are
guarded so it can be built for Hurd (I have not actually test it).
Checked on x86_64-linux-gnu, i686-linux-gnu, and with a i686-gnu
build.
---
Changes from v1:
- Changed close_range() comment to specify close() errors are
ignored.
- Fixed close_range() default implementation.
- __closefrom_fallback() for __ASSUME_CLOSE_RANGE.
---
include/unistd.h | 10 ++++++
io/Makefile | 3 +-
.../linux/closefrom.c => io/close_range.c | 34 ++++++++++++-------
io/closefrom.c | 16 +++++----
.../unix/sysv/linux => io}/tst-close_range.c | 8 +++++
posix/unistd.h | 10 ++++++
sysdeps/mach/hurd/Makefile | 2 +-
sysdeps/mach/hurd/bits/unistd_ext.h | 6 ----
sysdeps/mach/hurd/closefrom.c | 29 ----------------
sysdeps/mach/hurd/kernel-features.h | 2 ++
sysdeps/unix/sysv/linux/Makefile | 1 -
sysdeps/unix/sysv/linux/bits/unistd_ext.h | 9 -----
sysdeps/unix/sysv/linux/closefrom_fallback.c | 4 +++
sysdeps/unix/sysv/linux/kernel-features.h | 8 +++++
sysdeps/unix/sysv/linux/syscalls.list | 2 +-
15 files changed, 76 insertions(+), 68 deletions(-)
rename sysdeps/unix/sysv/linux/closefrom.c => io/close_range.c (59%)
rename {sysdeps/unix/sysv/linux => io}/tst-close_range.c (98%)
delete mode 100644 sysdeps/mach/hurd/closefrom.c
Comments
If no one oposes it I will commit this shortly.
On 08/11/2021 14:28, Adhemerval Zanella wrote:
> Now that Hurd implementis both close_range and closefrom (f2c996597d),
> we can make close_range() a base ABI, and make the default closefrom()
> implementation on top of close_range().
>
> The generic closefrom() implementation based on __getdtablesize() is
> moved to generic close_range(). On Linux it will be overriden by
> the auto-generation syscall while on Hurd it will be a system specific
> implementation.
>
> The closefrom() now calls close_range() and __closefrom_fallback().
> Since on Hurd close_range() does not fail, __closefrom_fallback() is an
> empty static inline function set by__ASSUME_CLOSE_RANGE.
>
> The __ASSUME_CLOSE_RANGE also allows optimize Linux
> __closefrom_fallback() implementation when --enable-kernel=5.9 or
> higher is used.
>
> Finally the Linux specific tst-close_range.c is moved to io and
> enabled as default. The Linuxism and CLOSE_RANGE_UNSHARE are
> guarded so it can be built for Hurd (I have not actually test it).
>
> Checked on x86_64-linux-gnu, i686-linux-gnu, and with a i686-gnu
> build.
> ---
> Changes from v1:
> - Changed close_range() comment to specify close() errors are
> ignored.
> - Fixed close_range() default implementation.
> - __closefrom_fallback() for __ASSUME_CLOSE_RANGE.
> ---
> include/unistd.h | 10 ++++++
> io/Makefile | 3 +-
> .../linux/closefrom.c => io/close_range.c | 34 ++++++++++++-------
> io/closefrom.c | 16 +++++----
> .../unix/sysv/linux => io}/tst-close_range.c | 8 +++++
> posix/unistd.h | 10 ++++++
> sysdeps/mach/hurd/Makefile | 2 +-
> sysdeps/mach/hurd/bits/unistd_ext.h | 6 ----
> sysdeps/mach/hurd/closefrom.c | 29 ----------------
> sysdeps/mach/hurd/kernel-features.h | 2 ++
> sysdeps/unix/sysv/linux/Makefile | 1 -
> sysdeps/unix/sysv/linux/bits/unistd_ext.h | 9 -----
> sysdeps/unix/sysv/linux/closefrom_fallback.c | 4 +++
> sysdeps/unix/sysv/linux/kernel-features.h | 8 +++++
> sysdeps/unix/sysv/linux/syscalls.list | 2 +-
> 15 files changed, 76 insertions(+), 68 deletions(-)
> rename sysdeps/unix/sysv/linux/closefrom.c => io/close_range.c (59%)
> rename {sysdeps/unix/sysv/linux => io}/tst-close_range.c (98%)
> delete mode 100644 sysdeps/mach/hurd/closefrom.c
>
> diff --git a/include/unistd.h b/include/unistd.h
> index 7849562c42..927d249380 100644
> --- a/include/unistd.h
> +++ b/include/unistd.h
> @@ -3,6 +3,9 @@
>
> # ifndef _ISOMAC
>
> +# include <stdbool.h>
> +# include <kernel-features.h>
> +
> libc_hidden_proto (_exit, __noreturn__)
> # ifndef NO_RTLD_HIDDEN
> rtld_hidden_proto (_exit, __noreturn__)
> @@ -158,7 +161,14 @@ extern int __brk (void *__addr) attribute_hidden;
> extern int __close (int __fd);
> libc_hidden_proto (__close)
> extern int __libc_close (int __fd);
> +#if __ASSUME_CLOSE_RANGE
> +static inline _Bool __closefrom_fallback (int __lowfd, _Bool dirfd_fallback)
> +{
> + return false;
> +}
> +#else
> extern _Bool __closefrom_fallback (int __lowfd, _Bool) attribute_hidden;
> +#endif
> extern ssize_t __read (int __fd, void *__buf, size_t __nbytes);
> libc_hidden_proto (__read)
> extern ssize_t __write (int __fd, const void *__buf, size_t __n);
> diff --git a/io/Makefile b/io/Makefile
> index ecf65aba60..83f6ffdb76 100644
> --- a/io/Makefile
> +++ b/io/Makefile
> @@ -57,7 +57,7 @@ routines := \
> utimensat futimens file_change_detection \
> fts64-time64 \
> ftw64-time64 \
> - closefrom
> + closefrom close_range
>
> others := pwd
> test-srcs := ftwtest ftwtest-time64
> @@ -79,6 +79,7 @@ tests := test-utime test-stat test-stat2 test-lfs tst-getcwd \
> tst-futimens \
> tst-utimensat \
> tst-closefrom \
> + tst-close_range \
> tst-ftw-bz28126
>
> tests-time64 := \
> diff --git a/sysdeps/unix/sysv/linux/closefrom.c b/io/close_range.c
> similarity index 59%
> rename from sysdeps/unix/sysv/linux/closefrom.c
> rename to io/close_range.c
> index 372896b775..26a615d8b9 100644
> --- a/sysdeps/unix/sysv/linux/closefrom.c
> +++ b/io/close_range.c
> @@ -1,4 +1,4 @@
> -/* Close a range of file descriptors. Linux version.
> +/* Close a range of file descriptors.
> Copyright (C) 2021 Free Software Foundation, Inc.
> This file is part of the GNU C Library.
>
> @@ -16,21 +16,29 @@
> License along with the GNU C Library; if not, see
> <https://www.gnu.org/licenses/>. */
>
> -#include <stdbool.h>
> -#include <stdio.h>
> -#include <sys/param.h>
> +#include <errno.h>
> +#include <not-cancel.h>
> #include <unistd.h>
>
> -void
> -__closefrom (int lowfd)
> +/* Close the file descriptors from FIRST up to LAST, inclusive. */
> +int
> +__close_range (unsigned int first, unsigned int last,
> + int flags)
> {
> - int l = MAX (0, lowfd);
> + if (first > last || flags != 0)
> + {
> + __set_errno (EINVAL);
> + return -1;
> + }
>
> - int r = __close_range (l, ~0U, 0);
> - if (r == 0)
> - return;
> + int maxfd = __getdtablesize ();
> + if (maxfd == -1)
> + return -1;
>
> - if (!__closefrom_fallback (l, true))
> - __fortify_fail ("closefrom failed to close a file descriptor");
> + for (int i = first; i <= last && i < maxfd; i++)
> + __close_nocancel_nostatus (i);
> +
> + return 0;
> }
> -weak_alias (__closefrom, closefrom)
> +libc_hidden_def (__close_range)
> +weak_alias (__close_range, close_range)
> diff --git a/io/closefrom.c b/io/closefrom.c
> index 01660a7531..e9167687bc 100644
> --- a/io/closefrom.c
> +++ b/io/closefrom.c
> @@ -16,19 +16,21 @@
> License along with the GNU C Library; if not, see
> <https://www.gnu.org/licenses/>. */
>
> +#include <stdbool.h>
> #include <stdio.h>
> +#include <sys/param.h>
> #include <unistd.h>
> -#include <not-cancel.h>
>
> void
> __closefrom (int lowfd)
> {
> - int maxfd = __getdtablesize ();
> - if (maxfd == -1)
> - __fortify_fail ("closefrom failed to get the file descriptor table size");
> + int l = MAX (0, lowfd);
>
> - for (int i = 0; i < maxfd; i++)
> - if (i >= lowfd)
> - __close_nocancel_nostatus (i);
> + int r = __close_range (l, ~0U, 0);
> + if (r == 0)
> + return ;
> +
> + if (!__closefrom_fallback (l, true))
> + __fortify_fail ("closefrom failed to close a file descriptor");
> }
> weak_alias (__closefrom, closefrom)
> diff --git a/sysdeps/unix/sysv/linux/tst-close_range.c b/io/tst-close_range.c
> similarity index 98%
> rename from sysdeps/unix/sysv/linux/tst-close_range.c
> rename to io/tst-close_range.c
> index f5069d1b8a..f05b4ff6ae 100644
> --- a/sysdeps/unix/sysv/linux/tst-close_range.c
> +++ b/io/tst-close_range.c
> @@ -119,6 +119,7 @@ close_range_test (void)
> support_descriptors_free (descrs);
> }
>
> +#ifdef __linux__
> _Noreturn static int
> close_range_test_fn (void *arg)
> {
> @@ -155,8 +156,10 @@ close_range_test_subprocess (void)
> support_descriptors_check (descrs);
> support_descriptors_free (descrs);
> }
> +#endif
>
>
> +#ifdef CLOSE_RANGE_UNSHARE
> _Noreturn static int
> close_range_unshare_test_fn (void *arg)
> {
> @@ -200,6 +203,7 @@ close_range_unshare_test (void)
> support_descriptors_check (descrs1);
> support_descriptors_free (descrs1);
> }
> +#endif
>
> static bool
> is_in_array (int *arr, size_t len, int fd)
> @@ -282,8 +286,12 @@ do_test (void)
> {
> close_range_test_max_upper_limit ();
> close_range_test ();
> +#ifdef __linux__
> close_range_test_subprocess ();
> +#endif
> +#ifdef CLOSE_RANGE_UNSHARE
> close_range_unshare_test ();
> +#endif
> close_range_cloexec_test ();
>
> return 0;
> diff --git a/posix/unistd.h b/posix/unistd.h
> index 7a61ff5e86..3c8a7ced6a 100644
> --- a/posix/unistd.h
> +++ b/posix/unistd.h
> @@ -1199,6 +1199,16 @@ int getentropy (void *__buffer, size_t __length) __wur
> __attr_access ((__write_only__, 1, 2));
> #endif
>
> +#ifdef __USE_GNU
> +/* Close all file descriptors in the range FD up to MAX_FD. The flag FLAGS
> + are define by the CLOSE_RANGE prefix. This function behaves like close
> + on the range and gaps where the file descriptor is invalid or errors
> + encountered while closing file descriptors are ignored. Returns 0 on
> + successor or -1 for failure (and sets errno accordingly). */
> +extern int close_range (unsigned int __fd, unsigned int __max_fd,
> + int __flags) __THROW;
> +#endif
> +
> /* Define some macros helping to catch buffer overflows. */
> #if __USE_FORTIFY_LEVEL > 0 && defined __fortify_function
> # include <bits/unistd.h>
> diff --git a/sysdeps/mach/hurd/Makefile b/sysdeps/mach/hurd/Makefile
> index 9acbe80f26..17bb643c18 100644
> --- a/sysdeps/mach/hurd/Makefile
> +++ b/sysdeps/mach/hurd/Makefile
> @@ -196,7 +196,7 @@ sysdep_routines += cthreads
> endif
>
> ifeq (io, $(subdir))
> -sysdep_routines += f_setlk close_nocancel close_nocancel_nostatus close_range \
> +sysdep_routines += f_setlk close_nocancel close_nocancel_nostatus \
> fcntl_nocancel open_nocancel openat_nocancel read_nocancel \
> pread64_nocancel write_nocancel pwrite64_nocancel \
> wait4_nocancel \
> diff --git a/sysdeps/mach/hurd/bits/unistd_ext.h b/sysdeps/mach/hurd/bits/unistd_ext.h
> index 288f504a3c..14f85539d5 100644
> --- a/sysdeps/mach/hurd/bits/unistd_ext.h
> +++ b/sysdeps/mach/hurd/bits/unistd_ext.h
> @@ -25,10 +25,4 @@
> /* Set the FD_CLOEXEC bit instead of closing the file descriptor. */
> #define CLOSE_RANGE_CLOEXEC (1U << 2)
>
> -/* Close the file descriptors from FIRST up to LAST, inclusive.
> - If CLOSE_RANGE_CLOEXEC is set in FLAGS, set the FD_CLOEXEC flag
> - instead of closing. */
> -extern int close_range (unsigned int __first, unsigned int __last,
> - int __flags) __THROW;
> -
> #endif /* __USE_GNU */
> diff --git a/sysdeps/mach/hurd/closefrom.c b/sysdeps/mach/hurd/closefrom.c
> deleted file mode 100644
> index 5d667cf6c4..0000000000
> --- a/sysdeps/mach/hurd/closefrom.c
> +++ /dev/null
> @@ -1,29 +0,0 @@
> -/* Close a range of file descriptors. Hurd version.
> - Copyright (C) 2021 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 <unistd.h>
> -#include <sys/param.h>
> -
> -void
> -__closefrom (int lowfd)
> -{
> - int l = MAX (0, lowfd);
> -
> - (void) __close_range (l, ~0U, 0);
> -}
> -weak_alias (__closefrom, closefrom)
> diff --git a/sysdeps/mach/hurd/kernel-features.h b/sysdeps/mach/hurd/kernel-features.h
> index 7d4eaee0a6..5fd37a6d7b 100644
> --- a/sysdeps/mach/hurd/kernel-features.h
> +++ b/sysdeps/mach/hurd/kernel-features.h
> @@ -19,3 +19,5 @@
> /* This file can define __ASSUME_* macros checked by certain source files.
> Almost none of these are used outside of sysdeps/unix/sysv/linux code.
> But those referring to POSIX-level features like O_* flags can be. */
> +
> +#define __ASSUME_CLOSE_RANGE 1
> diff --git a/sysdeps/unix/sysv/linux/Makefile b/sysdeps/unix/sysv/linux/Makefile
> index 76ad06361c..76042a6019 100644
> --- a/sysdeps/unix/sysv/linux/Makefile
> +++ b/sysdeps/unix/sysv/linux/Makefile
> @@ -120,7 +120,6 @@ tests += tst-clone tst-clone2 tst-clone3 tst-fanotify tst-personality \
> tst-timerfd tst-ppoll \
> tst-clock_adjtime tst-adjtimex tst-ntp_adjtime tst-ntp_gettime \
> tst-ntp_gettimex tst-sigtimedwait tst-misalign-clone \
> - tst-close_range \
> tst-prctl \
> tst-scm_rights \
> # tests
> diff --git a/sysdeps/unix/sysv/linux/bits/unistd_ext.h b/sysdeps/unix/sysv/linux/bits/unistd_ext.h
> index ae9994403c..8f422e60da 100644
> --- a/sysdeps/unix/sysv/linux/bits/unistd_ext.h
> +++ b/sysdeps/unix/sysv/linux/bits/unistd_ext.h
> @@ -47,13 +47,4 @@ extern __pid_t gettid (void) __THROW;
> # define CLOSE_RANGE_CLOEXEC (1U << 2)
> #endif
>
> -/* Close all file descriptors in the range FD up to MAX_FD. The flag FLAGS
> - are define by the CLOSE_RANGE prefix. This function behaves like close
> - on the range, but in a fail-safe where it will either fail and not close
> - any file descriptor or close all of them. Gaps where the file descriptor
> - is invalid are ignored. Returns 0 on successor or -1 for failure (and
> - sets errno accordingly). */
> -extern int close_range (unsigned int __fd, unsigned int __max_fd,
> - int __flags) __THROW;
> -
> #endif /* __USE_GNU */
> diff --git a/sysdeps/unix/sysv/linux/closefrom_fallback.c b/sysdeps/unix/sysv/linux/closefrom_fallback.c
> index f215fd2c09..a377ebc544 100644
> --- a/sysdeps/unix/sysv/linux/closefrom_fallback.c
> +++ b/sysdeps/unix/sysv/linux/closefrom_fallback.c
> @@ -21,6 +21,8 @@
> #include <not-cancel.h>
> #include <stdbool.h>
>
> +#if !__ASSUME_CLOSE_RANGE
> +
> /* Fallback code: iterates over /proc/self/fd, closing each file descriptor
> that fall on the criteria. If DIRFD_FALLBACK is set, a failure on
> /proc/self/fd open will trigger a fallback that tries to close a file
> @@ -97,3 +99,5 @@ err:
> __close_nocancel (dirfd);
> return ret;
> }
> +
> +#endif
> diff --git a/sysdeps/unix/sysv/linux/kernel-features.h b/sysdeps/unix/sysv/linux/kernel-features.h
> index ffb6af196b..a1108d434f 100644
> --- a/sysdeps/unix/sysv/linux/kernel-features.h
> +++ b/sysdeps/unix/sysv/linux/kernel-features.h
> @@ -220,6 +220,14 @@
> # define __ASSUME_FACCESSAT2 0
> #endif
>
> +/* The close_range system call was introduced across all architectures
> + in Linux 5.8. */
> +#if __LINUX_KERNEL_VERSION >= 0x050900
> +# define __ASSUME_CLOSE_RANGE 1
> +#else
> +# define __ASSUME_CLOSE_RANGE 0
> +#endif
> +
> /* The FUTEX_LOCK_PI2 operation was introduced across all architectures in Linux
> 5.14. */
> #if __LINUX_KERNEL_VERSION >= 0x050e00
> diff --git a/sysdeps/unix/sysv/linux/syscalls.list b/sysdeps/unix/sysv/linux/syscalls.list
> index 29899eb264..c38dbb34a1 100644
> --- a/sysdeps/unix/sysv/linux/syscalls.list
> +++ b/sysdeps/unix/sysv/linux/syscalls.list
> @@ -99,4 +99,4 @@ pkey_alloc EXTRA pkey_alloc i:ii pkey_alloc
> pkey_free EXTRA pkey_free i:i pkey_free
> gettid EXTRA gettid Ei: __gettid gettid
> tgkill EXTRA tgkill i:iii __tgkill tgkill
> -close_range EXTRA close_range i:iii __close_range close_range
> +close_range - close_range i:iii __close_range close_range
>
* Adhemerval Zanella via Libc-alpha:
> diff --git a/include/unistd.h b/include/unistd.h
> index 7849562c42..927d249380 100644
> --- a/include/unistd.h
> +++ b/include/unistd.h
> @@ -3,6 +3,9 @@
>
> # ifndef _ISOMAC
>
> +# include <stdbool.h>
> +# include <kernel-features.h>
> +
> libc_hidden_proto (_exit, __noreturn__)
> # ifndef NO_RTLD_HIDDEN
> rtld_hidden_proto (_exit, __noreturn__)
> @@ -158,7 +161,14 @@ extern int __brk (void *__addr) attribute_hidden;
> extern int __close (int __fd);
> libc_hidden_proto (__close)
> extern int __libc_close (int __fd);
> +#if __ASSUME_CLOSE_RANGE
> +static inline _Bool __closefrom_fallback (int __lowfd, _Bool dirfd_fallback)
> +{
> + return false;
> +}
> +#else
> extern _Bool __closefrom_fallback (int __lowfd, _Bool) attribute_hidden;
> +#endif
> extern ssize_t __read (int __fd, void *__buf, size_t __nbytes);
> libc_hidden_proto (__read)
> extern ssize_t __write (int __fd, const void *__buf, size_t __n);
#if indentation seems off.
I expect this will break the Hurd build because it does not define
__ASSUME_CLOSE_RANGE in its <kernel-features.h>.
Thanks,
Florian
On 24/11/2021 06:52, Florian Weimer wrote:
> * Adhemerval Zanella via Libc-alpha:
>
>> diff --git a/include/unistd.h b/include/unistd.h
>> index 7849562c42..927d249380 100644
>> --- a/include/unistd.h
>> +++ b/include/unistd.h
>> @@ -3,6 +3,9 @@
>>
>> # ifndef _ISOMAC
>>
>> +# include <stdbool.h>
>> +# include <kernel-features.h>
>> +
>> libc_hidden_proto (_exit, __noreturn__)
>> # ifndef NO_RTLD_HIDDEN
>> rtld_hidden_proto (_exit, __noreturn__)
>> @@ -158,7 +161,14 @@ extern int __brk (void *__addr) attribute_hidden;
>> extern int __close (int __fd);
>> libc_hidden_proto (__close)
>> extern int __libc_close (int __fd);
>> +#if __ASSUME_CLOSE_RANGE
>> +static inline _Bool __closefrom_fallback (int __lowfd, _Bool dirfd_fallback)
>> +{
>> + return false;
>> +}
>> +#else
>> extern _Bool __closefrom_fallback (int __lowfd, _Bool) attribute_hidden;
>> +#endif
>> extern ssize_t __read (int __fd, void *__buf, size_t __nbytes);
>> libc_hidden_proto (__read)
>> extern ssize_t __write (int __fd, const void *__buf, size_t __n);
>
> #if indentation seems off.
Ack.
>
> I expect this will break the Hurd build because it does not define
> __ASSUME_CLOSE_RANGE in its <kernel-features.h>.
> diff --git a/sysdeps/mach/hurd/kernel-features.h b/sysdeps/mach/hurd/kernel-features.h
> index 7d4eaee0a6..5fd37a6d7b 100644
> --- a/sysdeps/mach/hurd/kernel-features.h
> +++ b/sysdeps/mach/hurd/kernel-features.h
> @@ -19,3 +19,5 @@
> /* This file can define __ASSUME_* macros checked by certain source files.
> Almost none of these are used outside of sysdeps/unix/sysv/linux code.
> But those referring to POSIX-level features like O_* flags can be. */
> +
> +#define __ASSUME_CLOSE_RANGE 1
It does add it here (I also checked with a build for i688-gnu).
>
> Thanks,
> Florian
>
* Adhemerval Zanella:
>> diff --git a/sysdeps/mach/hurd/kernel-features.h b/sysdeps/mach/hurd/kernel-features.h
>> index 7d4eaee0a6..5fd37a6d7b 100644
>> --- a/sysdeps/mach/hurd/kernel-features.h
>> +++ b/sysdeps/mach/hurd/kernel-features.h
>> @@ -19,3 +19,5 @@
>> /* This file can define __ASSUME_* macros checked by certain source files.
>> Almost none of these are used outside of sysdeps/unix/sysv/linux code.
>> But those referring to POSIX-level features like O_* flags can be. */
>> +
>> +#define __ASSUME_CLOSE_RANGE 1
>
> It does add it here (I also checked with a build for i688-gnu).
Hmm, this doesn't match existing practice. We haven't unified
implementations in light of such divergence, I think. If the Hurd
developers don't object, it should be fine, though..
Thanks,
Florian
Florian Weimer, le mer. 24 nov. 2021 13:03:19 +0100, a ecrit:
> * Adhemerval Zanella:
>
> >> diff --git a/sysdeps/mach/hurd/kernel-features.h b/sysdeps/mach/hurd/kernel-features.h
> >> index 7d4eaee0a6..5fd37a6d7b 100644
> >> --- a/sysdeps/mach/hurd/kernel-features.h
> >> +++ b/sysdeps/mach/hurd/kernel-features.h
> >> @@ -19,3 +19,5 @@
> >> /* This file can define __ASSUME_* macros checked by certain source files.
> >> Almost none of these are used outside of sysdeps/unix/sysv/linux code.
> >> But those referring to POSIX-level features like O_* flags can be. */
> >> +
> >> +#define __ASSUME_CLOSE_RANGE 1
> >
> > It does add it here (I also checked with a build for i688-gnu).
>
> Hmm, this doesn't match existing practice. We haven't unified
> implementations in light of such divergence, I think. If the Hurd
> developers don't object, it should be fine, though..
I'm fine with it yes. This is not a "kernel-feature" since it's actually
implemented inside glibc itself, but from the point of view of the rest
of the world that's how people understand it, so better adhere to it :)
Samuel
On 24/11/2021 09:03, Florian Weimer wrote:
> * Adhemerval Zanella:
>
>>> diff --git a/sysdeps/mach/hurd/kernel-features.h b/sysdeps/mach/hurd/kernel-features.h
>>> index 7d4eaee0a6..5fd37a6d7b 100644
>>> --- a/sysdeps/mach/hurd/kernel-features.h
>>> +++ b/sysdeps/mach/hurd/kernel-features.h
>>> @@ -19,3 +19,5 @@
>>> /* This file can define __ASSUME_* macros checked by certain source files.
>>> Almost none of these are used outside of sysdeps/unix/sysv/linux code.
>>> But those referring to POSIX-level features like O_* flags can be. */
>>> +
>>> +#define __ASSUME_CLOSE_RANGE 1
>>
>> It does add it here (I also checked with a build for i688-gnu).
>
> Hmm, this doesn't match existing practice. We haven't unified
> implementations in light of such divergence, I think. If the Hurd
> developers don't object, it should be fine, though..
This was used before, we still have some leftovers from it:
nscd/nscd.c:306:# ifndef __ASSUME_IN_NONBLOCK
resolv/res_send.c:1035:#ifndef __ASSUME_SENDMMSG
resolv/res_send.c:1081:#ifndef __ASSUME_SENDMMSG
resolv/res_send.c:1100:#ifndef __ASSUME_SENDMMSG
You have also cleanup some other assumes from Hurd: dup3 (b48061e1a534a242),
O_CLOEXEC (cef9b65376a04430), and accept4 (e92030239abb4038).
On 24/11/2021 09:20, Adhemerval Zanella wrote:
>
>
> On 24/11/2021 09:03, Florian Weimer wrote:
>> * Adhemerval Zanella:
>>
>>>> diff --git a/sysdeps/mach/hurd/kernel-features.h b/sysdeps/mach/hurd/kernel-features.h
>>>> index 7d4eaee0a6..5fd37a6d7b 100644
>>>> --- a/sysdeps/mach/hurd/kernel-features.h
>>>> +++ b/sysdeps/mach/hurd/kernel-features.h
>>>> @@ -19,3 +19,5 @@
>>>> /* This file can define __ASSUME_* macros checked by certain source files.
>>>> Almost none of these are used outside of sysdeps/unix/sysv/linux code.
>>>> But those referring to POSIX-level features like O_* flags can be. */
>>>> +
>>>> +#define __ASSUME_CLOSE_RANGE 1
>>>
>>> It does add it here (I also checked with a build for i688-gnu).
>>
>> Hmm, this doesn't match existing practice. We haven't unified
>> implementations in light of such divergence, I think. If the Hurd
>> developers don't object, it should be fine, though..
>
> This was used before, we still have some leftovers from it:
>
> nscd/nscd.c:306:# ifndef __ASSUME_IN_NONBLOCK
On a side note, I think we can just remove it since it is only used
with inotify_init1 (which is only supported on Linux and currently
on all minimum supported kernel).
> resolv/res_send.c:1035:#ifndef __ASSUME_SENDMMSG
> resolv/res_send.c:1081:#ifndef __ASSUME_SENDMMSG
> resolv/res_send.c:1100:#ifndef __ASSUME_SENDMMSG
And we might remove it by implementing sendmmsg/recvmmsg on top of
sendmsg/recvmsg on generic implementations.
>
> You have also cleanup some other assumes from Hurd: dup3 (b48061e1a534a242),
> O_CLOEXEC (cef9b65376a04430), and accept4 (e92030239abb4038).
>
@@ -3,6 +3,9 @@
# ifndef _ISOMAC
+# include <stdbool.h>
+# include <kernel-features.h>
+
libc_hidden_proto (_exit, __noreturn__)
# ifndef NO_RTLD_HIDDEN
rtld_hidden_proto (_exit, __noreturn__)
@@ -158,7 +161,14 @@ extern int __brk (void *__addr) attribute_hidden;
extern int __close (int __fd);
libc_hidden_proto (__close)
extern int __libc_close (int __fd);
+#if __ASSUME_CLOSE_RANGE
+static inline _Bool __closefrom_fallback (int __lowfd, _Bool dirfd_fallback)
+{
+ return false;
+}
+#else
extern _Bool __closefrom_fallback (int __lowfd, _Bool) attribute_hidden;
+#endif
extern ssize_t __read (int __fd, void *__buf, size_t __nbytes);
libc_hidden_proto (__read)
extern ssize_t __write (int __fd, const void *__buf, size_t __n);
@@ -57,7 +57,7 @@ routines := \
utimensat futimens file_change_detection \
fts64-time64 \
ftw64-time64 \
- closefrom
+ closefrom close_range
others := pwd
test-srcs := ftwtest ftwtest-time64
@@ -79,6 +79,7 @@ tests := test-utime test-stat test-stat2 test-lfs tst-getcwd \
tst-futimens \
tst-utimensat \
tst-closefrom \
+ tst-close_range \
tst-ftw-bz28126
tests-time64 := \
similarity index 59%
rename from sysdeps/unix/sysv/linux/closefrom.c
rename to io/close_range.c
@@ -1,4 +1,4 @@
-/* Close a range of file descriptors. Linux version.
+/* Close a range of file descriptors.
Copyright (C) 2021 Free Software Foundation, Inc.
This file is part of the GNU C Library.
@@ -16,21 +16,29 @@
License along with the GNU C Library; if not, see
<https://www.gnu.org/licenses/>. */
-#include <stdbool.h>
-#include <stdio.h>
-#include <sys/param.h>
+#include <errno.h>
+#include <not-cancel.h>
#include <unistd.h>
-void
-__closefrom (int lowfd)
+/* Close the file descriptors from FIRST up to LAST, inclusive. */
+int
+__close_range (unsigned int first, unsigned int last,
+ int flags)
{
- int l = MAX (0, lowfd);
+ if (first > last || flags != 0)
+ {
+ __set_errno (EINVAL);
+ return -1;
+ }
- int r = __close_range (l, ~0U, 0);
- if (r == 0)
- return;
+ int maxfd = __getdtablesize ();
+ if (maxfd == -1)
+ return -1;
- if (!__closefrom_fallback (l, true))
- __fortify_fail ("closefrom failed to close a file descriptor");
+ for (int i = first; i <= last && i < maxfd; i++)
+ __close_nocancel_nostatus (i);
+
+ return 0;
}
-weak_alias (__closefrom, closefrom)
+libc_hidden_def (__close_range)
+weak_alias (__close_range, close_range)
@@ -16,19 +16,21 @@
License along with the GNU C Library; if not, see
<https://www.gnu.org/licenses/>. */
+#include <stdbool.h>
#include <stdio.h>
+#include <sys/param.h>
#include <unistd.h>
-#include <not-cancel.h>
void
__closefrom (int lowfd)
{
- int maxfd = __getdtablesize ();
- if (maxfd == -1)
- __fortify_fail ("closefrom failed to get the file descriptor table size");
+ int l = MAX (0, lowfd);
- for (int i = 0; i < maxfd; i++)
- if (i >= lowfd)
- __close_nocancel_nostatus (i);
+ int r = __close_range (l, ~0U, 0);
+ if (r == 0)
+ return ;
+
+ if (!__closefrom_fallback (l, true))
+ __fortify_fail ("closefrom failed to close a file descriptor");
}
weak_alias (__closefrom, closefrom)
similarity index 98%
rename from sysdeps/unix/sysv/linux/tst-close_range.c
rename to io/tst-close_range.c
@@ -119,6 +119,7 @@ close_range_test (void)
support_descriptors_free (descrs);
}
+#ifdef __linux__
_Noreturn static int
close_range_test_fn (void *arg)
{
@@ -155,8 +156,10 @@ close_range_test_subprocess (void)
support_descriptors_check (descrs);
support_descriptors_free (descrs);
}
+#endif
+#ifdef CLOSE_RANGE_UNSHARE
_Noreturn static int
close_range_unshare_test_fn (void *arg)
{
@@ -200,6 +203,7 @@ close_range_unshare_test (void)
support_descriptors_check (descrs1);
support_descriptors_free (descrs1);
}
+#endif
static bool
is_in_array (int *arr, size_t len, int fd)
@@ -282,8 +286,12 @@ do_test (void)
{
close_range_test_max_upper_limit ();
close_range_test ();
+#ifdef __linux__
close_range_test_subprocess ();
+#endif
+#ifdef CLOSE_RANGE_UNSHARE
close_range_unshare_test ();
+#endif
close_range_cloexec_test ();
return 0;
@@ -1199,6 +1199,16 @@ int getentropy (void *__buffer, size_t __length) __wur
__attr_access ((__write_only__, 1, 2));
#endif
+#ifdef __USE_GNU
+/* Close all file descriptors in the range FD up to MAX_FD. The flag FLAGS
+ are define by the CLOSE_RANGE prefix. This function behaves like close
+ on the range and gaps where the file descriptor is invalid or errors
+ encountered while closing file descriptors are ignored. Returns 0 on
+ successor or -1 for failure (and sets errno accordingly). */
+extern int close_range (unsigned int __fd, unsigned int __max_fd,
+ int __flags) __THROW;
+#endif
+
/* Define some macros helping to catch buffer overflows. */
#if __USE_FORTIFY_LEVEL > 0 && defined __fortify_function
# include <bits/unistd.h>
@@ -196,7 +196,7 @@ sysdep_routines += cthreads
endif
ifeq (io, $(subdir))
-sysdep_routines += f_setlk close_nocancel close_nocancel_nostatus close_range \
+sysdep_routines += f_setlk close_nocancel close_nocancel_nostatus \
fcntl_nocancel open_nocancel openat_nocancel read_nocancel \
pread64_nocancel write_nocancel pwrite64_nocancel \
wait4_nocancel \
@@ -25,10 +25,4 @@
/* Set the FD_CLOEXEC bit instead of closing the file descriptor. */
#define CLOSE_RANGE_CLOEXEC (1U << 2)
-/* Close the file descriptors from FIRST up to LAST, inclusive.
- If CLOSE_RANGE_CLOEXEC is set in FLAGS, set the FD_CLOEXEC flag
- instead of closing. */
-extern int close_range (unsigned int __first, unsigned int __last,
- int __flags) __THROW;
-
#endif /* __USE_GNU */
deleted file mode 100644
@@ -1,29 +0,0 @@
-/* Close a range of file descriptors. Hurd version.
- Copyright (C) 2021 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 <unistd.h>
-#include <sys/param.h>
-
-void
-__closefrom (int lowfd)
-{
- int l = MAX (0, lowfd);
-
- (void) __close_range (l, ~0U, 0);
-}
-weak_alias (__closefrom, closefrom)
@@ -19,3 +19,5 @@
/* This file can define __ASSUME_* macros checked by certain source files.
Almost none of these are used outside of sysdeps/unix/sysv/linux code.
But those referring to POSIX-level features like O_* flags can be. */
+
+#define __ASSUME_CLOSE_RANGE 1
@@ -120,7 +120,6 @@ tests += tst-clone tst-clone2 tst-clone3 tst-fanotify tst-personality \
tst-timerfd tst-ppoll \
tst-clock_adjtime tst-adjtimex tst-ntp_adjtime tst-ntp_gettime \
tst-ntp_gettimex tst-sigtimedwait tst-misalign-clone \
- tst-close_range \
tst-prctl \
tst-scm_rights \
# tests
@@ -47,13 +47,4 @@ extern __pid_t gettid (void) __THROW;
# define CLOSE_RANGE_CLOEXEC (1U << 2)
#endif
-/* Close all file descriptors in the range FD up to MAX_FD. The flag FLAGS
- are define by the CLOSE_RANGE prefix. This function behaves like close
- on the range, but in a fail-safe where it will either fail and not close
- any file descriptor or close all of them. Gaps where the file descriptor
- is invalid are ignored. Returns 0 on successor or -1 for failure (and
- sets errno accordingly). */
-extern int close_range (unsigned int __fd, unsigned int __max_fd,
- int __flags) __THROW;
-
#endif /* __USE_GNU */
@@ -21,6 +21,8 @@
#include <not-cancel.h>
#include <stdbool.h>
+#if !__ASSUME_CLOSE_RANGE
+
/* Fallback code: iterates over /proc/self/fd, closing each file descriptor
that fall on the criteria. If DIRFD_FALLBACK is set, a failure on
/proc/self/fd open will trigger a fallback that tries to close a file
@@ -97,3 +99,5 @@ err:
__close_nocancel (dirfd);
return ret;
}
+
+#endif
@@ -220,6 +220,14 @@
# define __ASSUME_FACCESSAT2 0
#endif
+/* The close_range system call was introduced across all architectures
+ in Linux 5.8. */
+#if __LINUX_KERNEL_VERSION >= 0x050900
+# define __ASSUME_CLOSE_RANGE 1
+#else
+# define __ASSUME_CLOSE_RANGE 0
+#endif
+
/* The FUTEX_LOCK_PI2 operation was introduced across all architectures in Linux
5.14. */
#if __LINUX_KERNEL_VERSION >= 0x050e00
@@ -99,4 +99,4 @@ pkey_alloc EXTRA pkey_alloc i:ii pkey_alloc
pkey_free EXTRA pkey_free i:i pkey_free
gettid EXTRA gettid Ei: __gettid gettid
tgkill EXTRA tgkill i:iii __tgkill tgkill
-close_range EXTRA close_range i:iii __close_range close_range
+close_range - close_range i:iii __close_range close_range