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Diffstat (limited to 'src/stat.h')
| -rw-r--r-- | src/stat.h | 172 |
1 files changed, 172 insertions, 0 deletions
diff --git a/src/stat.h b/src/stat.h new file mode 100644 index 0000000..8d7144d --- /dev/null +++ b/src/stat.h @@ -0,0 +1,172 @@ +// 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 BFS_USE_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 |