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Re: [PATCH] <sys/stat.h>: Use Linux kernel UAPI header if available and useful
* Florian Weimer:
> * Andreas Schwab:
>
>> On Jun 05 2019, Florian Weimer <fweimer@redhat.com> wrote:
>>
>>> * io/bits/statx.h: Fix typo in error message. Include
>>> <linux/stat.h> is available. Define statx-related constants only
>>
>> s/is/if/
>>
>>> diff --git a/io/bits/statx.h b/io/bits/statx.h
>>> index cff14b2543..d0dcc353ba 100644
>>> --- a/io/bits/statx.h
>>> +++ b/io/bits/statx.h
>>> @@ -19,9 +19,14 @@
>>> /* This interface is based on <linux/stat.h> in Linux. */
>>>
>>> #ifndef _SYS_STAT_H
>>> -# error Never include <bits/stat.x.h> directly, include <sys/stat.h> instead.
>>> +# error Never include <bits/statx.h> directly, include <sys/stat.h> instead.
>>> #endif
>>>
>>> +#if __glibc_has_include (<linux/stat.h>)
>>> +# include <linux/stat.h>
>>> +#endif
>>
>> Wouldn't it be better to add sysdeps/unix/sysv/linux/bits/statx.h where
>> <linux/stat.h> is included unconditionally?
>
> I don't think <linux/stat.h> exists as an UAPI header in Linux 3.2,
> which is currently the minimum kernel version. I think it was only
> added in Linux 3.7.
I'm not happy about the optics of referencing to <linux/stat.h> outside
the Linux sysdeps tree, but avoiding that is a bit involved. See the
patch below.
Thanks,
Florian
<sys/stat.h>: Use Linux kernel UAPI header if available and useful
This will automatically import new STATX_* constants. It also avoids
a conflict between <sys/stat.h> and <linux/stat.h>.
The 256 constant in the new static assert has been validated using
build-many-glibcs.py on all supported architectures.
2019-06-05 Florian Weimer <fweimer@redhat.com>
Linux: Use kernel headers for statx definitions if available.
* include/bits/statx-generic.h: New file.
* io/Makefile (headers): Add bits/statx-generic.h.
* io/bits/statx-generic.h: New file. Mostly copied from
io/bits/statx.h.
* io/bits/statx.h: Rewrite to include <bits/statx-generic.h>.
* sysdeps/unix/sysv/linux/bits/statx.h: New file.
* sysdeps/unix/sysv/linux/statx.c: Add static assert for the size
of struct statx.
diff --git a/include/bits/statx-generic.h b/include/bits/statx-generic.h
new file mode 100644
index 0000000000..21674721b6
--- /dev/null
+++ b/include/bits/statx-generic.h
@@ -0,0 +1 @@
+#include <io/bits/statx-generic.h>
diff --git a/io/Makefile b/io/Makefile
index f2404db041..7f0a861c56 100644
--- a/io/Makefile
+++ b/io/Makefile
@@ -25,7 +25,7 @@ include ../Makeconfig
headers := sys/stat.h bits/stat.h sys/statfs.h bits/statfs.h sys/vfs.h \
sys/statvfs.h bits/statvfs.h fcntl.h sys/fcntl.h bits/fcntl.h \
poll.h sys/poll.h bits/poll.h bits/fcntl2.h bits/poll2.h \
- bits/statx.h utime.h ftw.h fts.h sys/sendfile.h
+ bits/statx.h bits/statx-generic.h utime.h ftw.h fts.h sys/sendfile.h
routines := \
utime \
diff --git a/io/bits/statx-generic.h b/io/bits/statx-generic.h
new file mode 100644
index 0000000000..f183eaff49
--- /dev/null
+++ b/io/bits/statx-generic.h
@@ -0,0 +1,93 @@
+/* Generic statx-related definitions and declarations.
+ Copyright (C) 2018-2019 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/>. */
+
+/* This interface is based on <linux/stat.h> in Linux. */
+
+#ifndef _SYS_STAT_H
+# error Never include <bits/statx-generic.h> directly, include <sys/stat.h> instead.
+#endif
+
+#ifndef STATX_TYPE
+struct statx_timestamp
+{
+ __int64_t tv_sec;
+ __uint32_t tv_nsec;
+ __int32_t __statx_timestamp_pad1[1];
+};
+
+/* Warning: The kernel may add additional fields to this struct in the
+ future. Only use this struct for calling the statx function, not
+ for storing data. (Expansion will be controlled by the mask
+ argument of the statx function.) */
+struct statx
+{
+ __uint32_t stx_mask;
+ __uint32_t stx_blksize;
+ __uint64_t stx_attributes;
+ __uint32_t stx_nlink;
+ __uint32_t stx_uid;
+ __uint32_t stx_gid;
+ __uint16_t stx_mode;
+ __uint16_t __statx_pad1[1];
+ __uint64_t stx_ino;
+ __uint64_t stx_size;
+ __uint64_t stx_blocks;
+ __uint64_t stx_attributes_mask;
+ struct statx_timestamp stx_atime;
+ struct statx_timestamp stx_btime;
+ struct statx_timestamp stx_ctime;
+ struct statx_timestamp stx_mtime;
+ __uint32_t stx_rdev_major;
+ __uint32_t stx_rdev_minor;
+ __uint32_t stx_dev_major;
+ __uint32_t stx_dev_minor;
+ __uint64_t __statx_pad2[14];
+};
+
+# define STATX_TYPE 0x0001U
+# define STATX_MODE 0x0002U
+# define STATX_NLINK 0x0004U
+# define STATX_UID 0x0008U
+# define STATX_GID 0x0010U
+# define STATX_ATIME 0x0020U
+# define STATX_MTIME 0x0040U
+# define STATX_CTIME 0x0080U
+# define STATX_INO 0x0100U
+# define STATX_SIZE 0x0200U
+# define STATX_BLOCKS 0x0400U
+# define STATX_BASIC_STATS 0x07ffU
+# define STATX_ALL 0x0fffU
+# define STATX_BTIME 0x0800U
+# define STATX__RESERVED 0x80000000U
+
+# define STATX_ATTR_COMPRESSED 0x0004
+# define STATX_ATTR_IMMUTABLE 0x0010
+# define STATX_ATTR_APPEND 0x0020
+# define STATX_ATTR_NODUMP 0x0040
+# define STATX_ATTR_ENCRYPTED 0x0800
+# define STATX_ATTR_AUTOMOUNT 0x1000
+#endif /* !STATX_TYPE */
+
+__BEGIN_DECLS
+
+/* Fill *BUF with information about PATH in DIRFD. */
+int statx (int __dirfd, const char *__restrict __path, int __flags,
+ unsigned int __mask, struct statx *__restrict __buf)
+ __THROW __nonnull ((2, 5));
+
+__END_DECLS
diff --git a/io/bits/statx.h b/io/bits/statx.h
index cff14b2543..b3147bfa8a 100644
--- a/io/bits/statx.h
+++ b/io/bits/statx.h
@@ -1,4 +1,4 @@
-/* statx-related definitions and declarations.
+/* statx-related definitions and declarations. Generic version.
Copyright (C) 2018-2019 Free Software Foundation, Inc.
This file is part of the GNU C Library.
@@ -19,73 +19,8 @@
/* This interface is based on <linux/stat.h> in Linux. */
#ifndef _SYS_STAT_H
-# error Never include <bits/stat.x.h> directly, include <sys/stat.h> instead.
+# error Never include <bits/statx.h> directly, include <sys/stat.h> instead.
#endif
-struct statx_timestamp
-{
- __int64_t tv_sec;
- __uint32_t tv_nsec;
- __int32_t __statx_timestamp_pad1[1];
-};
-
-/* Warning: The kernel may add additional fields to this struct in the
- future. Only use this struct for calling the statx function, not
- for storing data. (Expansion will be controlled by the mask
- argument of the statx function.) */
-struct statx
-{
- __uint32_t stx_mask;
- __uint32_t stx_blksize;
- __uint64_t stx_attributes;
- __uint32_t stx_nlink;
- __uint32_t stx_uid;
- __uint32_t stx_gid;
- __uint16_t stx_mode;
- __uint16_t __statx_pad1[1];
- __uint64_t stx_ino;
- __uint64_t stx_size;
- __uint64_t stx_blocks;
- __uint64_t stx_attributes_mask;
- struct statx_timestamp stx_atime;
- struct statx_timestamp stx_btime;
- struct statx_timestamp stx_ctime;
- struct statx_timestamp stx_mtime;
- __uint32_t stx_rdev_major;
- __uint32_t stx_rdev_minor;
- __uint32_t stx_dev_major;
- __uint32_t stx_dev_minor;
- __uint64_t __statx_pad2[14];
-};
-
-#define STATX_TYPE 0x0001U
-#define STATX_MODE 0x0002U
-#define STATX_NLINK 0x0004U
-#define STATX_UID 0x0008U
-#define STATX_GID 0x0010U
-#define STATX_ATIME 0x0020U
-#define STATX_MTIME 0x0040U
-#define STATX_CTIME 0x0080U
-#define STATX_INO 0x0100U
-#define STATX_SIZE 0x0200U
-#define STATX_BLOCKS 0x0400U
-#define STATX_BASIC_STATS 0x07ffU
-#define STATX_ALL 0x0fffU
-#define STATX_BTIME 0x0800U
-#define STATX__RESERVED 0x80000000U
-
-#define STATX_ATTR_COMPRESSED 0x0004
-#define STATX_ATTR_IMMUTABLE 0x0010
-#define STATX_ATTR_APPEND 0x0020
-#define STATX_ATTR_NODUMP 0x0040
-#define STATX_ATTR_ENCRYPTED 0x0800
-#define STATX_ATTR_AUTOMOUNT 0x1000
-
-__BEGIN_DECLS
-
-/* Fill *BUF with information about PATH in DIRFD. */
-int statx (int __dirfd, const char *__restrict __path, int __flags,
- unsigned int __mask, struct statx *__restrict __buf)
- __THROW __nonnull ((2, 5));
-
-__END_DECLS
+/* Use the generic definitions. */
+#include <bits/statx-generic.h>
diff --git a/sysdeps/unix/sysv/linux/bits/statx.h b/sysdeps/unix/sysv/linux/bits/statx.h
new file mode 100644
index 0000000000..df782a571d
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/bits/statx.h
@@ -0,0 +1,30 @@
+/* statx-related definitions and declarations. Linux version.
+ Copyright (C) 2018-2019 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/>. */
+
+/* This interface is based on <linux/stat.h> in Linux. */
+
+#ifndef _SYS_STAT_H
+# error Never include <bits/statx.h> directly, include <sys/stat.h> instead.
+#endif
+
+/* Use the Linux kernel header if available. */
+#if __glibc_has_include (<linux/stat.h>)
+# include <linux/stat.h>
+#endif
+
+#include <bits/statx-generic.h>
diff --git a/sysdeps/unix/sysv/linux/statx.c b/sysdeps/unix/sysv/linux/statx.c
index b99e30dc3e..5d634960a6 100644
--- a/sysdeps/unix/sysv/linux/statx.c
+++ b/sysdeps/unix/sysv/linux/statx.c
@@ -21,6 +21,11 @@
#include "statx_generic.c"
+/* Ensure that the kernel headers have not changed the struct size.
+ If this ever happens, it may be necessary to introduce a new symbol
+ version. */
+_Static_assert (sizeof (struct statx) == 256, "struct statx size changed");
+
int
statx (int fd, const char *path, int flags,
unsigned int mask, struct statx *buf)