1 //===-- Convert Statfs to Statvfs -------------------------------*- C++ -*-===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8
9 #ifndef LLVM_LIBC_SRC_SYS_STATVFS_LINUX_STATFS_TO_STATVFS_H
10 #define LLVM_LIBC_SRC_SYS_STATVFS_LINUX_STATFS_TO_STATVFS_H
11
12 #include "include/llvm-libc-types/struct_statvfs.h"
13 #include "src/__support/CPP/optional.h"
14 #include "src/__support/OSUtil/syscall.h"
15 #include "src/__support/macros/attributes.h"
16 #include "src/__support/macros/config.h"
17 #include "src/errno/libc_errno.h"
18 #include <asm/statfs.h>
19 #include <sys/syscall.h>
20 namespace LIBC_NAMESPACE_DECL {
21
22 namespace statfs_utils {
23 #ifdef SYS_statfs64
24 using LinuxStatFs = statfs64;
25 #else
26 using LinuxStatFs = statfs;
27 #endif
28
29 // Linux kernel set an additional flag to f_flags. Libc should mask it out.
30 LIBC_INLINE_VAR constexpr decltype(LinuxStatFs::f_flags) ST_VALID = 0x0020;
31
linux_statfs(const char * path)32 LIBC_INLINE cpp::optional<LinuxStatFs> linux_statfs(const char *path) {
33 // The kernel syscall routine checks the validity of the path before filling
34 // the statfs structure. So, it is possible that the result is not initialized
35 // after the syscall. Since the struct is trvial, the compiler will generate
36 // pattern filling for the struct.
37 LinuxStatFs result;
38 // On 32-bit platforms, original statfs cannot handle large file systems.
39 // In such cases, SYS_statfs64 is defined and should be used.
40 #ifdef SYS_statfs64
41 int ret = syscall_impl<int>(SYS_statfs64, path, sizeof(result), &result);
42 #else
43 int ret = syscall_impl<int>(SYS_statfs, path, &result);
44 #endif
45 if (ret < 0) {
46 libc_errno = -ret;
47 return cpp::nullopt;
48 }
49 result.f_flags &= ~ST_VALID;
50 return result;
51 }
52
linux_fstatfs(int fd)53 LIBC_INLINE cpp::optional<LinuxStatFs> linux_fstatfs(int fd) {
54 // The kernel syscall routine checks the validity of the path before filling
55 // the statfs structure. So, it is possible that the result is not initialized
56 // after the syscall. Since the struct is trvial, the compiler will generate
57 // pattern filling for the struct.
58 LinuxStatFs result;
59 // On 32-bit platforms, original fstatfs cannot handle large file systems.
60 // In such cases, SYS_fstatfs64 is defined and should be used.
61 #ifdef SYS_fstatfs64
62 int ret = syscall_impl<int>(SYS_fstatfs64, fd, sizeof(result), &result);
63 #else
64 int ret = syscall_impl<int>(SYS_fstatfs, fd, &result);
65 #endif
66 if (ret < 0) {
67 libc_errno = -ret;
68 return cpp::nullopt;
69 }
70 result.f_flags &= ~ST_VALID;
71 return result;
72 }
73
74 // must use 'struct' tag to refer to type 'statvfs' in this scope. There will be
75 // a function in the same namespace with the same name. For consistency, we use
76 // struct prefix for all statvfs/statfs related types.
statfs_to_statvfs(const LinuxStatFs & in)77 LIBC_INLINE struct statvfs statfs_to_statvfs(const LinuxStatFs &in) {
78 struct statvfs out;
79 out.f_bsize = in.f_bsize;
80 out.f_frsize = in.f_frsize;
81 out.f_blocks = static_cast<decltype(out.f_blocks)>(in.f_blocks);
82 out.f_bfree = static_cast<decltype(out.f_bfree)>(in.f_bfree);
83 out.f_bavail = static_cast<decltype(out.f_bavail)>(in.f_bavail);
84 out.f_files = static_cast<decltype(out.f_files)>(in.f_files);
85 out.f_ffree = static_cast<decltype(out.f_ffree)>(in.f_ffree);
86 out.f_favail = static_cast<decltype(out.f_favail)>(in.f_ffree);
87 out.f_fsid = in.f_fsid.val[0];
88 if constexpr (sizeof(decltype(out.f_fsid)) == sizeof(uint64_t))
89 out.f_fsid |= static_cast<decltype(out.f_fsid)>(in.f_fsid.val[1]) << 32;
90 out.f_flag = in.f_flags;
91 out.f_namemax = in.f_namelen;
92 return out;
93 }
94 } // namespace statfs_utils
95 } // namespace LIBC_NAMESPACE_DECL
96
97 #endif // LLVM_LIBC_SRC_SYS_STATVFS_LINUX_STATFS_TO_STATVFS_H
98