#ifndef VLIBC_SYS_STATVFS_H
#define VLIBC_SYS_STATVFS_H

/*
 * vlibc — <sys/statvfs.h>.
 *
 * Filesystem statistics in an ABI-independent POSIX shape: block and file
 * counts as unsigned counts over a reported block size, plus the read-only
 * and setuid-disabling mount flags and the longest file name. This header
 * carries only the portable view; the Linux kernel's private <linux/statfs.h>
 * layout (signed longs, an int-pair f_fsid, a f_spare tail) never leaks
 * into it.
 *
 *   Level 2 (muslmimic): the whole header (statvfs and fstatvfs are XSI
 *                        [CX] in POSIX.1-2008, not base; the base filesystem
 *                        queries are stat()/fstat() in <sys/stat.h>).
 *
 * f_flag holds ST_RDONLY and/or ST_NOSUID, and f_fsid is a best-effort
 * filesystem identifier (the kernel does not populate it for every
 * filesystem). The block counts are measured in f_frsize units (which is
 * f_bsize when the filesystem does not distinguish a transfer size).
 *
 * None of these declarations carries an intent attribute: both functions
 * perform I/O with side effects and report failures through errno, so
 * const/pure would be unsound.
 */

#include <vlibc/features.h>

#include <sys/types.h> /* fsblkcnt_t, fsfilcnt_t */

#ifdef __cplusplus
extern "C" {
#endif

#if VLIBC_LEVEL_GE(2)
/* Level 2 (muslmimic): XSI. */

/*
 * Filesystem statistics. f_flag is a bitwise OR of ST_RDONLY and
 * ST_NOSUID; f_frsize is the fundamental block size the count fields are
 * expressed in. f_fsid is 0 when the filesystem provides no identifier.
 */
struct statvfs
{
    unsigned long f_bsize;   /* preferred I/O block size, bytes */
    unsigned long f_frsize;  /* fundamental block size, bytes */
    fsblkcnt_t f_blocks;     /* total blocks, in f_frsize units */
    fsblkcnt_t f_bfree;      /* free blocks */
    fsblkcnt_t f_bavail;     /* free blocks available to an unprivileged process */
    fsfilcnt_t f_files;      /* total file serial numbers (inodes) */
    fsfilcnt_t f_ffree;      /* free file serial numbers */
    fsfilcnt_t f_favail;     /* free serial numbers available to an unprivileged process */
    unsigned long f_fsid;    /* filesystem ID (best effort) */
    unsigned long f_flag;    /* mount flags: ST_RDONLY | ST_NOSUID */
    unsigned long f_namemax; /* maximum file name length */
};

/* f_flag values (also the kernel's f_flags bits on Linux). */
#define ST_RDONLY 1 /* read-only filesystem */
#define ST_NOSUID 2 /* set-user-ID/set-group-ID bits ignored on exec */

/*
 * Store statistics for the filesystem holding path into buf; return 0, or
 * -1 with errno set. XSI.
 */
int
statvfs(const char *restrict path, struct statvfs *restrict buf);

/*
 * Like statvfs(), for the filesystem holding the open descriptor fildes;
 * return 0, or -1 with errno set. XSI.
 */
int
fstatvfs(int fildes, struct statvfs *buf);
#endif /* VLIBC_LEVEL_GE(2) */

#ifdef __cplusplus
}
#endif

#endif /* VLIBC_SYS_STATVFS_H */