diff options
Diffstat (limited to 'stat.c')
| -rw-r--r-- | stat.c | 353 |
1 files changed, 0 insertions, 353 deletions
@@ -1,353 +0,0 @@ -/**************************************************************************** - * bfs * - * Copyright (C) 2018-2019 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 <assert.h> -#include <errno.h> -#include <fcntl.h> -#include <stdbool.h> -#include <string.h> -#include <sys/types.h> -#include <sys/stat.h> -#include <unistd.h> - -#ifdef STATX_BASIC_STATS -# define HAVE_STATX true -#elif __linux__ -# include <linux/stat.h> -# include <sys/syscall.h> -#endif - -#if HAVE_STATX || defined(__NR_statx) -# define HAVE_BFS_STATX true -#endif - -#if __APPLE__ -# define st_atim st_atimespec -# define st_ctim st_ctimespec -# define st_mtim st_mtimespec -# define st_birthtim st_birthtimespec -#endif - -const char *bfs_stat_field_name(enum bfs_stat_field field) { - switch (field) { - case BFS_STAT_DEV: - return "device number"; - case BFS_STAT_INO: - return "inode nunmber"; - case BFS_STAT_TYPE: - return "type"; - case BFS_STAT_MODE: - return "mode"; - case BFS_STAT_NLINK: - return "link count"; - case BFS_STAT_GID: - return "group ID"; - case BFS_STAT_UID: - return "user ID"; - case BFS_STAT_SIZE: - return "size"; - case BFS_STAT_BLOCKS: - return "block count"; - case BFS_STAT_RDEV: - return "underlying device"; - case BFS_STAT_ATIME: - return "access time"; - case BFS_STAT_BTIME: - return "birth time"; - case BFS_STAT_CTIME: - return "change time"; - case BFS_STAT_MTIME: - return "modification time"; - } - - assert(false); - return "???"; -} - -/** - * Check if we should retry a failed stat() due to a potentially broken link. - */ -static bool bfs_stat_retry(int ret, enum bfs_stat_flag flags) { - return ret != 0 - && (flags & (BFS_STAT_NOFOLLOW | BFS_STAT_TRYFOLLOW)) == BFS_STAT_TRYFOLLOW - && 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->rdev = statbuf->st_rdev; - buf->mask |= BFS_STAT_RDEV; - - 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, 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; -} - -#if HAVE_BFS_STATX - -/** - * Wrapper for the statx() system call, which had no glibc wrapper prior to 2.28. - */ -static int bfs_statx(int at_fd, const char *at_path, int at_flags, unsigned int mask, struct statx *buf) { - // -fsanitize=memory doesn't know about statx(), so tell it the memory - // got initialized -#if BFS_HAS_FEATURE(memory_sanitizer, false) - memset(buf, 0, sizeof(*buf)); -#endif - -#if HAVE_STATX - return statx(at_fd, at_path, at_flags, mask, buf); -#else - return syscall(__NR_statx, at_fd, at_path, at_flags, mask, buf); -#endif -} - -/** - * 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, flags)) { - at_flags |= AT_SYMLINK_NOFOLLOW; - ret = bfs_statx(at_fd, at_path, at_flags, mask, &xbuf); - } - - if (ret != 0) { - return ret; - } - - // Callers shouldn't have to check anything except the times - const unsigned int guaranteed = STATX_BASIC_STATS ^ (STATX_ATIME | STATX_CTIME | STATX_MTIME); - if ((xbuf.stx_mask & guaranteed) != guaranteed) { - errno = ENOTSUP; - return -1; - } - - buf->mask = 0; - - buf->dev = bfs_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; - } - - buf->rdev = bfs_makedev(xbuf.stx_rdev_major, xbuf.stx_rdev_minor); - buf->mask |= BFS_STAT_RDEV; - - 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 // HAVE_BFS_STATX - -/** - * Allows calling stat with custom at_flags. - */ -static int bfs_stat_explicit(int at_fd, const char *at_path, int at_flags, enum bfs_stat_flag flags, struct bfs_stat *buf) { -#if HAVE_BFS_STATX - 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_stat(int at_fd, const char *at_path, enum bfs_stat_flag flags, struct bfs_stat *buf) { - int at_flags = 0; - if (flags & BFS_STAT_NOFOLLOW) { - at_flags |= AT_SYMLINK_NOFOLLOW; - } - - if (at_path) { - return bfs_stat_explicit(at_fd, at_path, at_flags, flags, buf); - } - -#ifdef AT_EMPTY_PATH - static bool has_at_ep = true; - if (has_at_ep) { - at_flags |= AT_EMPTY_PATH; - int ret = bfs_stat_explicit(at_fd, "", at_flags, flags, buf); - if (ret != 0 && errno == EINVAL) { - has_at_ep = false; - } else { - return ret; - } - } -#endif - - struct stat statbuf; - if (fstat(at_fd, &statbuf) == 0) { - bfs_stat_convert(&statbuf, buf); - return 0; - } else { - return -1; - } -} - -const struct timespec *bfs_stat_time(const struct bfs_stat *buf, enum bfs_stat_field field) { - if (!(buf->mask & field)) { - errno = ENOTSUP; - return NULL; - } - - switch (field) { - case BFS_STAT_ATIME: - return &buf->atime; - case BFS_STAT_BTIME: - return &buf->btime; - case BFS_STAT_CTIME: - return &buf->ctime; - case BFS_STAT_MTIME: - return &buf->mtime; - default: - assert(false); - errno = EINVAL; - return NULL; - } -} - -void bfs_stat_id(const struct bfs_stat *buf, bfs_file_id *id) { - memcpy(*id, &buf->dev, sizeof(buf->dev)); - memcpy(*id + sizeof(buf->dev), &buf->ino, sizeof(buf->ino)); -} |