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234 lines
7.6 KiB
C
234 lines
7.6 KiB
C
/* fsusage.c -- return space usage of mounted file systems
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Copyright (C) 1991-1992, 1996, 1998-1999, 2002-2006, 2009-2022 Free Software
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Foundation, Inc.
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This file is free software: you can redistribute it and/or modify
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it under the terms of the GNU Lesser General Public License as
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published by the Free Software Foundation; either version 3 of the
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License, or (at your option) any later version.
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This file is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with this program. If not, see <https://www.gnu.org/licenses/>. */
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#include <config.h>
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#include "fsusage.h"
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#include <limits.h>
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#include <sys/types.h>
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#if STAT_STATVFS || STAT_STATVFS64 /* POSIX 1003.1-2001 (and later) with XSI */
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# include <sys/statvfs.h>
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#else
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/* Don't include backward-compatibility files unless they're needed.
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Eventually we'd like to remove all this cruft. */
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# include <fcntl.h>
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# include <unistd.h>
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# include <sys/stat.h>
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#if HAVE_SYS_PARAM_H
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# include <sys/param.h>
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#endif
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#if HAVE_SYS_MOUNT_H
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# include <sys/mount.h>
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#endif
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#if HAVE_SYS_VFS_H
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# include <sys/vfs.h>
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#endif
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# if HAVE_SYS_FS_S5PARAM_H /* Fujitsu UXP/V */
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# include <sys/fs/s5param.h>
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# endif
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# if HAVE_SYS_STATFS_H
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# include <sys/statfs.h>
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# endif
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#endif
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/* Many space usage primitives use all 1 bits to denote a value that is
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not applicable or unknown. Propagate this information by returning
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a uintmax_t value that is all 1 bits if X is all 1 bits, even if X
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is unsigned and narrower than uintmax_t. */
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#define PROPAGATE_ALL_ONES(x) \
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((sizeof (x) < sizeof (uintmax_t) \
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&& (~ (x) == (sizeof (x) < sizeof (int) \
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? - (1 << (sizeof (x) * CHAR_BIT)) \
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: 0))) \
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? UINTMAX_MAX : (uintmax_t) (x))
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/* Extract the top bit of X as an uintmax_t value. */
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#define EXTRACT_TOP_BIT(x) ((x) \
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& ((uintmax_t) 1 << (sizeof (x) * CHAR_BIT - 1)))
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/* If a value is negative, many space usage primitives store it into an
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integer variable by assignment, even if the variable's type is unsigned.
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So, if a space usage variable X's top bit is set, convert X to the
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uintmax_t value V such that (- (uintmax_t) V) is the negative of
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the original value. If X's top bit is clear, just yield X.
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Use PROPAGATE_TOP_BIT if the original value might be negative;
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otherwise, use PROPAGATE_ALL_ONES. */
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#define PROPAGATE_TOP_BIT(x) ((x) | ~ (EXTRACT_TOP_BIT (x) - 1))
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#ifdef STAT_STATVFS
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/* Return true if statvfs works. This is false for statvfs on systems
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with GNU libc on Linux kernels before 2.6.36, which stats all
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preceding entries in /proc/mounts; that makes df hang if even one
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of the corresponding file systems is hard-mounted but not available. */
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# if ! (__linux__ && (__GLIBC__ || __UCLIBC__))
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/* The FRSIZE fallback is not required in this case. */
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# undef STAT_STATFS2_FRSIZE
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static int statvfs_works (void) { return 1; }
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# else
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# include <string.h> /* for strverscmp */
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# include <sys/utsname.h>
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# include <sys/statfs.h>
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# define STAT_STATFS2_BSIZE 1
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static int
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statvfs_works (void)
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{
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static int statvfs_works_cache = -1;
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struct utsname name;
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if (statvfs_works_cache < 0)
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statvfs_works_cache = (uname (&name) == 0
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&& 0 <= strverscmp (name.release, "2.6.36"));
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return statvfs_works_cache;
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}
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# endif
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#endif
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/* Fill in the fields of FSP with information about space usage for
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the file system on which FILE resides.
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DISK is the device on which FILE is mounted, for space-getting
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methods that need to know it.
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Return 0 if successful, -1 if not. When returning -1, ensure that
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ERRNO is either a system error value, or zero if DISK is NULL
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on a system that requires a non-NULL value. */
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int
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get_fs_usage (char const *file, char const *disk, struct fs_usage *fsp)
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{
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#ifdef STAT_STATVFS /* POSIX, except pre-2.6.36 glibc/Linux */
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if (statvfs_works ())
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{
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struct statvfs vfsd;
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if (statvfs (file, &vfsd) < 0)
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return -1;
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/* f_frsize isn't guaranteed to be supported. */
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fsp->fsu_blocksize = (vfsd.f_frsize
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? PROPAGATE_ALL_ONES (vfsd.f_frsize)
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: PROPAGATE_ALL_ONES (vfsd.f_bsize));
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fsp->fsu_blocks = PROPAGATE_ALL_ONES (vfsd.f_blocks);
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fsp->fsu_bfree = PROPAGATE_ALL_ONES (vfsd.f_bfree);
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fsp->fsu_bavail = PROPAGATE_TOP_BIT (vfsd.f_bavail);
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fsp->fsu_bavail_top_bit_set = EXTRACT_TOP_BIT (vfsd.f_bavail) != 0;
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fsp->fsu_files = PROPAGATE_ALL_ONES (vfsd.f_files);
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fsp->fsu_ffree = PROPAGATE_ALL_ONES (vfsd.f_ffree);
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return 0;
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}
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#endif
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#if defined STAT_STATVFS64 /* AIX */
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struct statvfs64 fsd;
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if (statvfs64 (file, &fsd) < 0)
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return -1;
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/* f_frsize isn't guaranteed to be supported. */
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fsp->fsu_blocksize = (fsd.f_frsize
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? PROPAGATE_ALL_ONES (fsd.f_frsize)
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: PROPAGATE_ALL_ONES (fsd.f_bsize));
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#elif defined STAT_STATFS3_OSF1 /* OSF/1 */
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struct statfs fsd;
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if (statfs (file, &fsd, sizeof (struct statfs)) != 0)
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return -1;
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fsp->fsu_blocksize = PROPAGATE_ALL_ONES (fsd.f_fsize);
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#elif defined STAT_STATFS2_FRSIZE /* 2.6 < glibc/Linux < 2.6.36 */
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struct statfs fsd;
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if (statfs (file, &fsd) < 0)
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return -1;
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fsp->fsu_blocksize = PROPAGATE_ALL_ONES (fsd.f_frsize);
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#elif defined STAT_STATFS2_BSIZE /* glibc/Linux < 2.6, 4.3BSD, SunOS 4, \
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Mac OS X < 10.4, FreeBSD < 5.0, \
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NetBSD < 3.0, OpenBSD < 4.4 */
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struct statfs fsd;
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if (statfs (file, &fsd) < 0)
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return -1;
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fsp->fsu_blocksize = PROPAGATE_ALL_ONES (fsd.f_bsize);
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# ifdef STATFS_TRUNCATES_BLOCK_COUNTS
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/* In SunOS 4.1.2, 4.1.3, and 4.1.3_U1, the block counts in the
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struct statfs are truncated to 2GB. These conditions detect that
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truncation, presumably without botching the 4.1.1 case, in which
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the values are not truncated. The correct counts are stored in
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undocumented spare fields. */
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if (fsd.f_blocks == 0x7fffffff / fsd.f_bsize && fsd.f_spare[0] > 0)
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{
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fsd.f_blocks = fsd.f_spare[0];
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fsd.f_bfree = fsd.f_spare[1];
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fsd.f_bavail = fsd.f_spare[2];
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}
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# endif /* STATFS_TRUNCATES_BLOCK_COUNTS */
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#elif defined STAT_STATFS2_FSIZE /* 4.4BSD and older NetBSD */
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struct statfs fsd;
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if (statfs (file, &fsd) < 0)
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return -1;
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fsp->fsu_blocksize = PROPAGATE_ALL_ONES (fsd.f_fsize);
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#elif defined STAT_STATFS4 /* SVR3, old Irix */
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struct statfs fsd;
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if (statfs (file, &fsd, sizeof fsd, 0) < 0)
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return -1;
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/* Empirically, the block counts on most SVR3 and SVR3-derived
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systems seem to always be in terms of 512-byte blocks,
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no matter what value f_bsize has. */
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fsp->fsu_blocksize = 512;
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#endif
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#if (defined STAT_STATVFS64 || defined STAT_STATFS3_OSF1 \
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|| defined STAT_STATFS2_FRSIZE || defined STAT_STATFS2_BSIZE \
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|| defined STAT_STATFS2_FSIZE || defined STAT_STATFS4)
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fsp->fsu_blocks = PROPAGATE_ALL_ONES (fsd.f_blocks);
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fsp->fsu_bfree = PROPAGATE_ALL_ONES (fsd.f_bfree);
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fsp->fsu_bavail = PROPAGATE_TOP_BIT (fsd.f_bavail);
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fsp->fsu_bavail_top_bit_set = EXTRACT_TOP_BIT (fsd.f_bavail) != 0;
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fsp->fsu_files = PROPAGATE_ALL_ONES (fsd.f_files);
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fsp->fsu_ffree = PROPAGATE_ALL_ONES (fsd.f_ffree);
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#endif
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(void) disk; /* avoid argument-unused warning */
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return 0;
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}
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