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/****************************************************************************
* bfs *
* Copyright (C) 2018 Tavian Barnes <tavianator@tavianator.com> *
* *
* Permission to use, copy, modify, and/or distribute this software for any *
* purpose with or without fee is hereby granted. *
* *
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES *
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF *
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR *
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES *
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN *
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF *
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. *
****************************************************************************/
#include "stat.h"
#include "util.h"
#include <errno.h>
#include <fcntl.h>
#include <stdbool.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#if __linux__
# include <linux/stat.h>
# include <sys/syscall.h>
# include <sys/sysmacros.h>
#elif __APPLE__
# define st_atim st_atimespec
# define st_ctim st_ctimespec
# define st_mtim st_mtimespec
# define st_birthtim st_birthtimespec
#endif
/**
* Check if we should retry a failed stat() due to a potentially broken link.
*/
static bool bfs_stat_retry(int ret, int at_flags, enum bfs_stat_flag flags) {
return ret != 0
&& !(at_flags & AT_SYMLINK_NOFOLLOW)
&& (flags & BFS_STAT_BROKEN_OK)
&& is_nonexistence_error(errno);
}
/**
* Convert a struct stat to a struct bfs_stat.
*/
static void bfs_stat_convert(const struct stat *statbuf, struct bfs_stat *buf) {
buf->mask = 0;
buf->dev = statbuf->st_dev;
buf->mask |= BFS_STAT_DEV;
buf->ino = statbuf->st_ino;
buf->mask |= BFS_STAT_INO;
buf->mode = statbuf->st_mode;
buf->mask |= BFS_STAT_TYPE | BFS_STAT_MODE;
buf->nlink = statbuf->st_nlink;
buf->mask |= BFS_STAT_NLINK;
buf->gid = statbuf->st_gid;
buf->mask |= BFS_STAT_GID;
buf->uid = statbuf->st_uid;
buf->mask |= BFS_STAT_UID;
buf->size = statbuf->st_size;
buf->mask |= BFS_STAT_SIZE;
buf->blocks = statbuf->st_blocks;
buf->mask |= BFS_STAT_BLOCKS;
buf->atime = statbuf->st_atim;
buf->mask |= BFS_STAT_ATIME;
buf->ctime = statbuf->st_ctim;
buf->mask |= BFS_STAT_CTIME;
buf->mtime = statbuf->st_mtim;
buf->mask |= BFS_STAT_MTIME;
#if __APPLE__ || __FreeBSD__ || __NetBSD__
buf->btime = statbuf->st_birthtim;
buf->mask |= BFS_STAT_BTIME;
#endif
}
/**
* bfs_stat() implementation backed by stat().
*/
static int bfs_stat_impl(int at_fd, const char *at_path, int at_flags, enum bfs_stat_flag flags, struct bfs_stat *buf) {
struct stat statbuf;
int ret = fstatat(at_fd, at_path, &statbuf, at_flags);
if (bfs_stat_retry(ret, at_flags, flags)) {
at_flags |= AT_SYMLINK_NOFOLLOW;
ret = fstatat(at_fd, at_path, &statbuf, at_flags);
}
if (ret == 0) {
bfs_stat_convert(&statbuf, buf);
}
return ret;
}
#ifdef STATX_BASIC_STATS
/**
* Wrapper for the statx() system call, which has no native glibc wrapper.
*/
static int bfs_statx(int at_fd, const char *at_path, int at_flags, unsigned int mask, struct statx *buf) {
return syscall(__NR_statx, at_fd, at_path, at_flags, mask, buf);
}
/**
* bfs_stat() implementation backed by statx().
*/
static int bfs_statx_impl(int at_fd, const char *at_path, int at_flags, enum bfs_stat_flag flags, struct bfs_stat *buf) {
unsigned int mask = STATX_BASIC_STATS | STATX_BTIME;
struct statx xbuf;
int ret = bfs_statx(at_fd, at_path, at_flags, mask, &xbuf);
if (bfs_stat_retry(ret, at_flags, flags)) {
at_flags |= AT_SYMLINK_NOFOLLOW;
ret = bfs_statx(at_fd, at_path, at_flags, mask, &xbuf);
}
if (ret != 0) {
return ret;
}
if ((xbuf.stx_mask & STATX_BASIC_STATS) != STATX_BASIC_STATS) {
// Callers shouldn't have to check anything except BFS_STAT_BTIME
errno = EINVAL;
return -1;
}
buf->mask = 0;
buf->dev = makedev(xbuf.stx_dev_major, xbuf.stx_dev_minor);
buf->mask |= BFS_STAT_DEV;
if (xbuf.stx_mask & STATX_INO) {
buf->ino = xbuf.stx_ino;
buf->mask |= BFS_STAT_INO;
}
buf->mode = xbuf.stx_mode;
if (xbuf.stx_mask & STATX_TYPE) {
buf->mask |= BFS_STAT_TYPE;
}
if (xbuf.stx_mask & STATX_MODE) {
buf->mask |= BFS_STAT_MODE;
}
if (xbuf.stx_mask & STATX_NLINK) {
buf->nlink = xbuf.stx_nlink;
buf->mask |= BFS_STAT_NLINK;
}
if (xbuf.stx_mask & STATX_GID) {
buf->gid = xbuf.stx_gid;
buf->mask |= BFS_STAT_GID;
}
if (xbuf.stx_mask & STATX_UID) {
buf->uid = xbuf.stx_uid;
buf->mask |= BFS_STAT_UID;
}
if (xbuf.stx_mask & STATX_SIZE) {
buf->size = xbuf.stx_size;
buf->mask |= BFS_STAT_SIZE;
}
if (xbuf.stx_mask & STATX_BLOCKS) {
buf->blocks = xbuf.stx_blocks;
buf->mask |= BFS_STAT_BLOCKS;
}
if (xbuf.stx_mask & STATX_ATIME) {
buf->atime.tv_sec = xbuf.stx_atime.tv_sec;
buf->atime.tv_nsec = xbuf.stx_atime.tv_nsec;
buf->mask |= BFS_STAT_ATIME;
}
if (xbuf.stx_mask & STATX_BTIME) {
buf->btime.tv_sec = xbuf.stx_btime.tv_sec;
buf->btime.tv_nsec = xbuf.stx_btime.tv_nsec;
buf->mask |= BFS_STAT_BTIME;
}
if (xbuf.stx_mask & STATX_CTIME) {
buf->ctime.tv_sec = xbuf.stx_ctime.tv_sec;
buf->ctime.tv_nsec = xbuf.stx_ctime.tv_nsec;
buf->mask |= BFS_STAT_CTIME;
}
if (xbuf.stx_mask & STATX_MTIME) {
buf->mtime.tv_sec = xbuf.stx_mtime.tv_sec;
buf->mtime.tv_nsec = xbuf.stx_mtime.tv_nsec;
buf->mask |= BFS_STAT_MTIME;
}
return ret;
}
#endif // STATX_BASIC_STATS
int bfs_stat(int at_fd, const char *at_path, int at_flags, enum bfs_stat_flag flags, struct bfs_stat *buf) {
#ifdef STATX_BASIC_STATS
static bool has_statx = true;
if (has_statx) {
int ret = bfs_statx_impl(at_fd, at_path, at_flags, flags, buf);
if (ret != 0 && errno == ENOSYS) {
has_statx = false;
} else {
return ret;
}
}
#endif
return bfs_stat_impl(at_fd, at_path, at_flags, flags, buf);
}
int bfs_fstat(int fd, struct bfs_stat *buf) {
#ifdef AT_EMPTY_PATH
return bfs_stat(fd, "", AT_EMPTY_PATH, 0, buf);
#else
struct stat statbuf;
int ret = fstat(fd, &statbuf);
if (ret == 0) {
bfs_stat_convert(&statbuf, buf);
}
return ret;
#endif
}
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