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/* fsusage.c -- return space usage of mounted file systems
Copyright (C) 1991-1992, 1996, 1998-1999, 2002-2006, 2009-2020 Free Software
Foundation, Inc.
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
This program 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 General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <https://www.gnu.org/licenses/>. */
#include <config.h>
#include "fsusage.h"
#include <limits.h>
#include <sys/types.h>
#if STAT_STATVFS || STAT_STATVFS64 /* POSIX 1003.1-2001 (and later) with XSI */
# include <sys/statvfs.h>
#else
/* Don't include backward-compatibility files unless they're needed.
Eventually we'd like to remove all this cruft. */
# include <fcntl.h>
# include <unistd.h>
# include <sys/stat.h>
#if HAVE_SYS_PARAM_H
# include <sys/param.h>
#endif
#if HAVE_SYS_MOUNT_H
# include <sys/mount.h>
#endif
#if HAVE_SYS_VFS_H
# include <sys/vfs.h>
#endif
# if HAVE_SYS_FS_S5PARAM_H /* Fujitsu UXP/V */
# include <sys/fs/s5param.h>
# endif
# if HAVE_SYS_STATFS_H
# include <sys/statfs.h>
# endif
#endif
/* Many space usage primitives use all 1 bits to denote a value that is
not applicable or unknown. Propagate this information by returning
a uintmax_t value that is all 1 bits if X is all 1 bits, even if X
is unsigned and narrower than uintmax_t. */
#define PROPAGATE_ALL_ONES(x) \
((sizeof (x) < sizeof (uintmax_t) \
&& (~ (x) == (sizeof (x) < sizeof (int) \
? - (1 << (sizeof (x) * CHAR_BIT)) \
: 0))) \
? UINTMAX_MAX : (uintmax_t) (x))
/* Extract the top bit of X as an uintmax_t value. */
#define EXTRACT_TOP_BIT(x) ((x) \
& ((uintmax_t) 1 << (sizeof (x) * CHAR_BIT - 1)))
/* If a value is negative, many space usage primitives store it into an
integer variable by assignment, even if the variable's type is unsigned.
So, if a space usage variable X's top bit is set, convert X to the
uintmax_t value V such that (- (uintmax_t) V) is the negative of
the original value. If X's top bit is clear, just yield X.
Use PROPAGATE_TOP_BIT if the original value might be negative;
otherwise, use PROPAGATE_ALL_ONES. */
#define PROPAGATE_TOP_BIT(x) ((x) | ~ (EXTRACT_TOP_BIT (x) - 1))
#ifdef STAT_STATVFS
/* Return true if statvfs works. This is false for statvfs on systems
with GNU libc on Linux kernels before 2.6.36, which stats all
preceding entries in /proc/mounts; that makes df hang if even one
of the corresponding file systems is hard-mounted but not available. */
# if ! (__linux__ && (__GLIBC__ || __UCLIBC__))
/* The FRSIZE fallback is not required in this case. */
# undef STAT_STATFS2_FRSIZE
static int statvfs_works (void) { return 1; }
# else
# include <string.h> /* for strverscmp */
# include <sys/utsname.h>
# include <sys/statfs.h>
# define STAT_STATFS2_BSIZE 1
static int
statvfs_works (void)
{
static int statvfs_works_cache = -1;
struct utsname name;
if (statvfs_works_cache < 0)
statvfs_works_cache = (uname (&name) == 0
&& 0 <= strverscmp (name.release, "2.6.36"));
return statvfs_works_cache;
}
# endif
#endif
/* Fill in the fields of FSP with information about space usage for
the file system on which FILE resides.
DISK is the device on which FILE is mounted, for space-getting
methods that need to know it.
Return 0 if successful, -1 if not. When returning -1, ensure that
ERRNO is either a system error value, or zero if DISK is NULL
on a system that requires a non-NULL value. */
int
get_fs_usage (char const *file, char const *disk, struct fs_usage *fsp)
{
#ifdef STAT_STATVFS /* POSIX, except pre-2.6.36 glibc/Linux */
if (statvfs_works ())
{
struct statvfs vfsd;
if (statvfs (file, &vfsd) < 0)
return -1;
/* f_frsize isn't guaranteed to be supported. */
fsp->fsu_blocksize = (vfsd.f_frsize
? PROPAGATE_ALL_ONES (vfsd.f_frsize)
: PROPAGATE_ALL_ONES (vfsd.f_bsize));
fsp->fsu_blocks = PROPAGATE_ALL_ONES (vfsd.f_blocks);
fsp->fsu_bfree = PROPAGATE_ALL_ONES (vfsd.f_bfree);
fsp->fsu_bavail = PROPAGATE_TOP_BIT (vfsd.f_bavail);
fsp->fsu_bavail_top_bit_set = EXTRACT_TOP_BIT (vfsd.f_bavail) != 0;
fsp->fsu_files = PROPAGATE_ALL_ONES (vfsd.f_files);
fsp->fsu_ffree = PROPAGATE_ALL_ONES (vfsd.f_ffree);
return 0;
}
#endif
#if defined STAT_STATVFS64 /* AIX */
struct statvfs64 fsd;
if (statvfs64 (file, &fsd) < 0)
return -1;
/* f_frsize isn't guaranteed to be supported. */
fsp->fsu_blocksize = (fsd.f_frsize
? PROPAGATE_ALL_ONES (fsd.f_frsize)
: PROPAGATE_ALL_ONES (fsd.f_bsize));
#elif defined STAT_STATFS3_OSF1 /* OSF/1 */
struct statfs fsd;
if (statfs (file, &fsd, sizeof (struct statfs)) != 0)
return -1;
fsp->fsu_blocksize = PROPAGATE_ALL_ONES (fsd.f_fsize);
#elif defined STAT_STATFS2_FRSIZE /* 2.6 < glibc/Linux < 2.6.36 */
struct statfs fsd;
if (statfs (file, &fsd) < 0)
return -1;
fsp->fsu_blocksize = PROPAGATE_ALL_ONES (fsd.f_frsize);
#elif defined STAT_STATFS2_BSIZE /* glibc/Linux < 2.6, 4.3BSD, SunOS 4, \
Mac OS X < 10.4, FreeBSD < 5.0, \
NetBSD < 3.0, OpenBSD < 4.4 */
struct statfs fsd;
if (statfs (file, &fsd) < 0)
return -1;
fsp->fsu_blocksize = PROPAGATE_ALL_ONES (fsd.f_bsize);
# ifdef STATFS_TRUNCATES_BLOCK_COUNTS
/* In SunOS 4.1.2, 4.1.3, and 4.1.3_U1, the block counts in the
struct statfs are truncated to 2GB. These conditions detect that
truncation, presumably without botching the 4.1.1 case, in which
the values are not truncated. The correct counts are stored in
undocumented spare fields. */
if (fsd.f_blocks == 0x7fffffff / fsd.f_bsize && fsd.f_spare[0] > 0)
{
fsd.f_blocks = fsd.f_spare[0];
fsd.f_bfree = fsd.f_spare[1];
fsd.f_bavail = fsd.f_spare[2];
}
# endif /* STATFS_TRUNCATES_BLOCK_COUNTS */
#elif defined STAT_STATFS2_FSIZE /* 4.4BSD and older NetBSD */
struct statfs fsd;
if (statfs (file, &fsd) < 0)
return -1;
fsp->fsu_blocksize = PROPAGATE_ALL_ONES (fsd.f_fsize);
#elif defined STAT_STATFS4 /* SVR3, old Irix */
struct statfs fsd;
if (statfs (file, &fsd, sizeof fsd, 0) < 0)
return -1;
/* Empirically, the block counts on most SVR3 and SVR3-derived
systems seem to always be in terms of 512-byte blocks,
no matter what value f_bsize has. */
fsp->fsu_blocksize = 512;
#endif
#if (defined STAT_STATVFS64 || defined STAT_STATFS3_OSF1 \
|| defined STAT_STATFS2_FRSIZE || defined STAT_STATFS2_BSIZE \
|| defined STAT_STATFS2_FSIZE || defined STAT_STATFS4)
fsp->fsu_blocks = PROPAGATE_ALL_ONES (fsd.f_blocks);
fsp->fsu_bfree = PROPAGATE_ALL_ONES (fsd.f_bfree);
fsp->fsu_bavail = PROPAGATE_TOP_BIT (fsd.f_bavail);
fsp->fsu_bavail_top_bit_set = EXTRACT_TOP_BIT (fsd.f_bavail) != 0;
fsp->fsu_files = PROPAGATE_ALL_ONES (fsd.f_files);
fsp->fsu_ffree = PROPAGATE_ALL_ONES (fsd.f_ffree);
#endif
(void) disk; /* avoid argument-unused warning */
return 0;
}
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