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1 | /* Generic implementation of statx based on fstatat64. | |
2 | Copyright (C) 2018-2024 Free Software Foundation, Inc. | |
3 | This file is part of the GNU C Library. | |
4 | ||
5 | The GNU C Library is free software; you can redistribute it and/or | |
6 | modify it under the terms of the GNU Lesser General Public | |
7 | License as published by the Free Software Foundation; either | |
8 | version 2.1 of the License, or (at your option) any later version. | |
9 | ||
10 | The GNU C Library is distributed in the hope that it will be useful, | |
11 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
13 | Lesser General Public License for more details. | |
14 | ||
15 | You should have received a copy of the GNU Lesser General Public | |
16 | License along with the GNU C Library; if not, see | |
17 | <https://www.gnu.org/licenses/>. */ | |
18 | ||
19 | #include <errno.h> | |
20 | #include <fcntl.h> | |
21 | #include <string.h> | |
22 | #include <sys/stat.h> | |
23 | #include <sys/sysmacros.h> | |
24 | ||
25 | /* Obtain the original definition of struct statx. */ | |
26 | #undef __statx_defined | |
27 | #define statx original_statx | |
28 | #include <bits/types/struct_statx.h> | |
29 | #undef statx | |
30 | ||
31 | static inline struct statx_timestamp | |
32 | statx_convert_timestamp (struct timespec tv) | |
33 | { | |
34 | return (struct statx_timestamp) { tv.tv_sec, tv.tv_nsec }; | |
35 | } | |
36 | ||
37 | /* Approximate emulation of statx. This will always fill in | |
38 | POSIX-mandated attributes even if the underlying file system does | |
39 | not actually support it (for example, GID and UID on file systems | |
40 | without UNIX-style permissions). */ | |
41 | static __attribute__ ((unused)) int | |
42 | statx_generic (int fd, const char *path, int flags, | |
43 | unsigned int mask, struct statx *buf) | |
44 | { | |
45 | /* Flags which need to be cleared before passing them to | |
46 | fstatat64. */ | |
47 | static const int clear_flags = AT_STATX_SYNC_AS_STAT; | |
48 | ||
49 | /* Flags supported by our emulation. */ | |
50 | static const int supported_flags | |
51 | = AT_EMPTY_PATH | AT_NO_AUTOMOUNT | AT_SYMLINK_NOFOLLOW | clear_flags; | |
52 | ||
53 | if (__glibc_unlikely ((flags & ~supported_flags) != 0)) | |
54 | { | |
55 | __set_errno (EINVAL); | |
56 | return -1; | |
57 | } | |
58 | ||
59 | struct stat64 st; | |
60 | int ret = __fstatat64 (fd, path, &st, flags & ~clear_flags); | |
61 | if (ret != 0) | |
62 | return ret; | |
63 | ||
64 | /* The interface is defined in such a way that unused (padding) | |
65 | fields have to be cleared. STATX_BASIC_STATS corresponds to the | |
66 | data which is available via fstatat64. */ | |
67 | struct original_statx obuf = | |
68 | { | |
69 | .stx_mask = STATX_BASIC_STATS, | |
70 | .stx_blksize = st.st_blksize, | |
71 | .stx_nlink = st.st_nlink, | |
72 | .stx_uid = st.st_uid, | |
73 | .stx_gid = st.st_gid, | |
74 | .stx_mode = st.st_mode, | |
75 | .stx_ino = st.st_ino, | |
76 | .stx_size = st.st_size, | |
77 | .stx_blocks = st.st_blocks, | |
78 | .stx_atime = statx_convert_timestamp (st.st_atim), | |
79 | .stx_ctime = statx_convert_timestamp (st.st_ctim), | |
80 | .stx_mtime = statx_convert_timestamp (st.st_mtim), | |
81 | .stx_rdev_major = major (st.st_rdev), | |
82 | .stx_rdev_minor = minor (st.st_rdev), | |
83 | .stx_dev_major = major (st.st_dev), | |
84 | .stx_dev_minor = minor (st.st_dev), | |
85 | }; | |
86 | _Static_assert (sizeof (*buf) >= sizeof (obuf), "struct statx size"); | |
87 | memcpy (buf, &obuf, sizeof (obuf)); | |
88 | ||
89 | return 0; | |
90 | } |