1 use std::env;
2 use std::ffi::{CString, OsStr};
3 use std::fs::{self, File, OpenOptions};
4 use std::io;
5 use std::os::unix::ffi::OsStrExt;
6 use std::os::unix::fs::{MetadataExt, OpenOptionsExt};
7 use std::path::Path;
8 use crate::util;
9
10 #[cfg(not(target_os = "redox"))]
11 use libc::{c_char, c_int, link, rename, unlink};
12
13 #[cfg(not(target_os = "redox"))]
14 #[inline(always)]
cvt_err(result: c_int) -> io::Result<c_int>15 pub fn cvt_err(result: c_int) -> io::Result<c_int> {
16 if result == -1 {
17 Err(io::Error::last_os_error())
18 } else {
19 Ok(result)
20 }
21 }
22
23 #[cfg(target_os = "redox")]
24 #[inline(always)]
cvt_err(result: Result<usize, syscall::Error>) -> io::Result<usize>25 pub fn cvt_err(result: Result<usize, syscall::Error>) -> io::Result<usize> {
26 result.map_err(|err| io::Error::from_raw_os_error(err.errno))
27 }
28
29 // Stolen from std.
cstr(path: &Path) -> io::Result<CString>30 pub fn cstr(path: &Path) -> io::Result<CString> {
31 CString::new(path.as_os_str().as_bytes())
32 .map_err(|_| io::Error::new(io::ErrorKind::InvalidInput, "path contained a null"))
33 }
34
create_named(path: &Path, open_options: &mut OpenOptions) -> io::Result<File>35 pub fn create_named(path: &Path, open_options: &mut OpenOptions) -> io::Result<File> {
36 open_options
37 .read(true)
38 .write(true)
39 .create_new(true)
40 .mode(0o600)
41 .open(path)
42 }
43
create_unlinked(path: &Path) -> io::Result<File>44 fn create_unlinked(path: &Path) -> io::Result<File> {
45 let tmp;
46 // shadow this to decrease the lifetime. It can't live longer than `tmp`.
47 let mut path = path;
48 if !path.is_absolute() {
49 let cur_dir = env::current_dir()?;
50 tmp = cur_dir.join(path);
51 path = &tmp;
52 }
53
54 let f = create_named(path, &mut OpenOptions::new())?;
55 // don't care whether the path has already been unlinked,
56 // but perhaps there are some IO error conditions we should send up?
57 let _ = fs::remove_file(path);
58 Ok(f)
59 }
60
61 #[cfg(target_os = "linux")]
create(dir: &Path) -> io::Result<File>62 pub fn create(dir: &Path) -> io::Result<File> {
63 use libc::{EISDIR, ENOENT, EOPNOTSUPP, O_EXCL, O_TMPFILE};
64 OpenOptions::new()
65 .read(true)
66 .write(true)
67 .custom_flags(O_TMPFILE | O_EXCL) // do not mix with `create_new(true)`
68 .open(dir)
69 .or_else(|e| {
70 match e.raw_os_error() {
71 // These are the three "not supported" error codes for O_TMPFILE.
72 Some(EOPNOTSUPP) | Some(EISDIR) | Some(ENOENT) => create_unix(dir),
73 _ => Err(e),
74 }
75 })
76 }
77
78 #[cfg(not(target_os = "linux"))]
create(dir: &Path) -> io::Result<File>79 pub fn create(dir: &Path) -> io::Result<File> {
80 create_unix(dir)
81 }
82
create_unix(dir: &Path) -> io::Result<File>83 fn create_unix(dir: &Path) -> io::Result<File> {
84 util::create_helper(
85 dir,
86 OsStr::new(".tmp"),
87 OsStr::new(""),
88 crate::NUM_RAND_CHARS,
89 |path| create_unlinked(&path),
90 )
91 }
92
reopen(file: &File, path: &Path) -> io::Result<File>93 pub fn reopen(file: &File, path: &Path) -> io::Result<File> {
94 let new_file = OpenOptions::new().read(true).write(true).open(path)?;
95 let old_meta = file.metadata()?;
96 let new_meta = new_file.metadata()?;
97 if old_meta.dev() != new_meta.dev() || old_meta.ino() != new_meta.ino() {
98 return Err(io::Error::new(
99 io::ErrorKind::NotFound,
100 "original tempfile has been replaced",
101 ));
102 }
103 Ok(new_file)
104 }
105
106 #[cfg(not(target_os = "redox"))]
persist(old_path: &Path, new_path: &Path, overwrite: bool) -> io::Result<()>107 pub fn persist(old_path: &Path, new_path: &Path, overwrite: bool) -> io::Result<()> {
108 unsafe {
109 let old_path = cstr(old_path)?;
110 let new_path = cstr(new_path)?;
111 if overwrite {
112 cvt_err(rename(
113 old_path.as_ptr() as *const c_char,
114 new_path.as_ptr() as *const c_char,
115 ))?;
116 } else {
117 cvt_err(link(
118 old_path.as_ptr() as *const c_char,
119 new_path.as_ptr() as *const c_char,
120 ))?;
121 // Ignore unlink errors. Can we do better?
122 // On recent linux, we can use renameat2 to do this atomically.
123 let _ = unlink(old_path.as_ptr() as *const c_char);
124 }
125 Ok(())
126 }
127 }
128
129 #[cfg(target_os = "redox")]
persist(old_path: &Path, new_path: &Path, overwrite: bool) -> io::Result<()>130 pub fn persist(old_path: &Path, new_path: &Path, overwrite: bool) -> io::Result<()> {
131 // XXX implement when possible
132 Err(io::Error::from_raw_os_error(syscall::ENOSYS))
133 }
134
keep(_: &Path) -> io::Result<()>135 pub fn keep(_: &Path) -> io::Result<()> {
136 Ok(())
137 }
138