glibc/sysdeps/unix/sysv/linux/internal_statvfs.c
наб 92861d93cd linux: statvfs: allocate spare for f_type
This is the only missing part in struct statvfs.
The LSB calls [f]statfs() deprecated, and its weird types are definitely
off-putting. However, its use is required to get f_type.

Instead, allocate one of the six spares to f_type,
copied directly from struct statfs.
This then becomes a small glibc extension to the standard interface
on Linux and the Hurd, instead of two different interfaces, one of which
is quite odd due to being an ABI type, and there no longer is any reason
to use statfs().

The underlying kernel type is a mess, but all architectures agree on u32
(or more) for the ABI, and all filesystem magicks are 32-bit integers.
We don't lose any generality by using u32, and by doing so we both make
the API consistent with the Hurd, and allow C++
  switch(f_type) { case RAMFS_MAGIC: ...; }

Also fix tst-statvfs so that it actually fails;
as it stood, all it did was return 0 always.
Test statfs()' and statvfs()' f_types are the same.

Link: https://lore.kernel.org/linux-man/f54kudgblgk643u32tb6at4cd3kkzha6hslahv24szs4raroaz@ogivjbfdaqtb/t/#u
Signed-off-by: Ahelenia Ziemiańska <nabijaczleweli@nabijaczleweli.xyz>
Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
2023-08-08 09:29:06 -03:00

113 lines
4.2 KiB
C

/* Copyright (C) 1998-2023 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/statfs.h>
#include <sys/statvfs.h>
#include <internal_statvfs.h>
#include <string.h>
#include <time.h>
#include <kernel_stat.h>
/* Special internal-only bit value. */
# define ST_VALID 0x0020
#if !STATFS_IS_STATFS64
void
__internal_statvfs (struct statvfs *buf, const struct statfs *fsbuf)
{
/* Now fill in the fields we have information for. */
buf->f_bsize = fsbuf->f_bsize;
/* Linux has the f_frsize size only in later version of the kernel.
If the value is not filled in use f_bsize. */
buf->f_frsize = fsbuf->f_frsize ?: fsbuf->f_bsize;
buf->f_blocks = fsbuf->f_blocks;
buf->f_bfree = fsbuf->f_bfree;
buf->f_bavail = fsbuf->f_bavail;
buf->f_files = fsbuf->f_files;
buf->f_ffree = fsbuf->f_ffree;
if (sizeof (buf->f_fsid) == sizeof (fsbuf->f_fsid))
/* The shifting uses 'unsigned long long int' even though the target
field might only have 32 bits. This is OK since the 'if' branch
is not used in this case but the compiler would still generate
warnings. */
buf->f_fsid = ((fsbuf->f_fsid.__val[0]
& ((1ULL << (8 * sizeof (fsbuf->f_fsid.__val[0]))) - 1))
| ((unsigned long long int) fsbuf->f_fsid.__val[1]
<< (8 * (sizeof (buf->f_fsid)
- sizeof (fsbuf->f_fsid.__val[0])))));
else
/* We cannot help here. The statvfs element is not large enough to
contain both words of the statfs f_fsid field. */
buf->f_fsid = fsbuf->f_fsid.__val[0];
#ifdef _STATVFSBUF_F_UNUSED
buf->__f_unused = 0;
#endif
buf->f_namemax = fsbuf->f_namelen;
buf->f_type = fsbuf->f_type;
memset (buf->__f_spare, '\0', sizeof (buf->__f_spare));
/* What remains to do is to fill the fields f_favail and f_flag. */
/* XXX I have no idea how to compute f_favail. Any idea??? */
buf->f_favail = buf->f_ffree;
buf->f_flag = fsbuf->f_flags ^ ST_VALID;
}
#endif
void
__internal_statvfs64 (struct statvfs64 *buf, const struct statfs64 *fsbuf)
{
/* Now fill in the fields we have information for. */
buf->f_bsize = fsbuf->f_bsize;
/* Linux has the f_frsize size only in later version of the kernel.
If the value is not filled in use f_bsize. */
buf->f_frsize = fsbuf->f_frsize ?: fsbuf->f_bsize;
buf->f_blocks = fsbuf->f_blocks;
buf->f_bfree = fsbuf->f_bfree;
buf->f_bavail = fsbuf->f_bavail;
buf->f_files = fsbuf->f_files;
buf->f_ffree = fsbuf->f_ffree;
if (sizeof (buf->f_fsid) == sizeof (fsbuf->f_fsid))
/* The shifting uses 'unsigned long long int' even though the target
field might only have 32 bits. This is OK since the 'if' branch
is not used in this case but the compiler would still generate
warnings. */
buf->f_fsid = ((fsbuf->f_fsid.__val[0]
& ((1ULL << (8 * sizeof (fsbuf->f_fsid.__val[0]))) - 1))
| ((unsigned long long int) fsbuf->f_fsid.__val[1]
<< (8 * (sizeof (buf->f_fsid)
- sizeof (fsbuf->f_fsid.__val[0])))));
else
/* We cannot help here. The statvfs element is not large enough to
contain both words of the statfs f_fsid field. */
buf->f_fsid = fsbuf->f_fsid.__val[0];
#ifdef _STATVFSBUF_F_UNUSED
buf->__f_unused = 0;
#endif
buf->f_namemax = fsbuf->f_namelen;
buf->f_type = fsbuf->f_type;
memset (buf->__f_spare, '\0', sizeof (buf->__f_spare));
/* What remains to do is to fill the fields f_favail and f_flag. */
/* XXX I have no idea how to compute f_favail. Any idea??? */
buf->f_favail = buf->f_ffree;
buf->f_flag = fsbuf->f_flags ^ ST_VALID;
}