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// Copyright © Tavian Barnes <tavianator@tavianator.com>
// SPDX-License-Identifier: 0BSD
/**
* A facade over the stat() API that unifies some details that diverge between
* implementations, like the names of the timespec fields and the presence of
* file "birth" times. On new enough Linux kernels, the facade is backed by
* statx() instead, and so it exposes a similar interface with a mask for which
* fields were successfully returned.
*/
#ifndef BFS_STAT_H
#define BFS_STAT_H
#include "prelude.h"
#include <sys/stat.h>
#include <sys/types.h>
#include <time.h>
#if !BFS_HAS_STATX && BFS_HAS_STATX_SYSCALL
# include <linux/stat.h>
#endif
#ifndef BFS_USE_STATX
# define BFS_USE_STATX (BFS_HAS_STATX || BFS_HAS_STATX_SYSCALL)
#endif
#if __has_include(<sys/param.h>)
# include <sys/param.h>
#endif
#ifdef DEV_BSIZE
# define BFS_STAT_BLKSIZE DEV_BSIZE
#elif defined(S_BLKSIZE)
# define BFS_STAT_BLKSIZE S_BLKSIZE
#else
# define BFS_STAT_BLKSIZE 512
#endif
/**
* bfs_stat field bitmask.
*/
enum bfs_stat_field {
BFS_STAT_MODE = 1 << 0,
BFS_STAT_DEV = 1 << 1,
BFS_STAT_INO = 1 << 2,
BFS_STAT_NLINK = 1 << 3,
BFS_STAT_GID = 1 << 4,
BFS_STAT_UID = 1 << 5,
BFS_STAT_SIZE = 1 << 6,
BFS_STAT_BLOCKS = 1 << 7,
BFS_STAT_RDEV = 1 << 8,
BFS_STAT_ATTRS = 1 << 9,
BFS_STAT_ATIME = 1 << 10,
BFS_STAT_BTIME = 1 << 11,
BFS_STAT_CTIME = 1 << 12,
BFS_STAT_MTIME = 1 << 13,
};
/**
* Get the human-readable name of a bfs_stat field.
*/
const char *bfs_stat_field_name(enum bfs_stat_field field);
/**
* bfs_stat() flags.
*/
enum bfs_stat_flags {
/** Follow symlinks (the default). */
BFS_STAT_FOLLOW = 0,
/** Never follow symlinks. */
BFS_STAT_NOFOLLOW = 1 << 0,
/** Try to follow symlinks, but fall back to the link itself if broken. */
BFS_STAT_TRYFOLLOW = 1 << 1,
/** Try to use cached values without synchronizing remote filesystems. */
BFS_STAT_NOSYNC = 1 << 2,
};
/**
* Facade over struct stat.
*/
struct bfs_stat {
/** Bitmask indicating filled fields. */
enum bfs_stat_field mask;
/** File type and access mode. */
mode_t mode;
/** Device ID containing the file. */
dev_t dev;
/** Inode number. */
ino_t ino;
/** Number of hard links. */
nlink_t nlink;
/** Owner group ID. */
gid_t gid;
/** Owner user ID. */
uid_t uid;
/** File size in bytes. */
off_t size;
/** Number of disk blocks allocated (of size BFS_STAT_BLKSIZE). */
blkcnt_t blocks;
/** The device ID represented by this file. */
dev_t rdev;
/** Attributes/flags set on the file. */
unsigned long long attrs;
/** Access time. */
struct timespec atime;
/** Birth/creation time. */
struct timespec btime;
/** Status change time. */
struct timespec ctime;
/** Modification time. */
struct timespec mtime;
};
/**
* Facade over fstatat().
*
* @param at_fd
* The base file descriptor for the lookup.
* @param at_path
* The path to stat, relative to at_fd. Pass NULL to fstat() at_fd
* itself.
* @param flags
* Flags that affect the lookup.
* @param[out] buf
* A place to store the stat buffer, if successful.
* @return
* 0 on success, -1 on error.
*/
int bfs_stat(int at_fd, const char *at_path, enum bfs_stat_flags flags, struct bfs_stat *buf);
/**
* Convert bfs_stat_flags to fstatat() flags.
*/
int bfs_fstatat_flags(enum bfs_stat_flags flags);
/**
* Convert struct stat to struct bfs_stat.
*/
void bfs_stat_convert(struct bfs_stat *dest, const struct stat *src);
#if BFS_USE_STATX
/**
* Convert bfs_stat_flags to statx() flags.
*/
int bfs_statx_flags(enum bfs_stat_flags flags);
/**
* Convert struct statx to struct bfs_stat.
*/
int bfs_statx_convert(struct bfs_stat *dest, const struct statx *src);
#endif
/**
* Get a particular time field from a bfs_stat() buffer.
*/
const struct timespec *bfs_stat_time(const struct bfs_stat *buf, enum bfs_stat_field field);
/**
* A unique ID for a file.
*/
typedef unsigned char bfs_file_id[sizeof(dev_t) + sizeof(ino_t)];
/**
* Compute a unique ID for a file.
*/
void bfs_stat_id(const struct bfs_stat *buf, bfs_file_id *id);
#endif // BFS_STAT_H
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