sysinfo/linux/
utils.rs

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1// Take a look at the license at the top of the repository in the LICENSE file.
2
3use std::fs::File;
4use std::io::{self, Read, Seek};
5use std::path::{Path, PathBuf};
6
7use crate::sys::system::REMAINING_FILES;
8
9pub(crate) fn get_all_data_from_file(file: &mut File, size: usize) -> io::Result<String> {
10    let mut buf = String::with_capacity(size);
11    file.rewind()?;
12    file.read_to_string(&mut buf)?;
13    Ok(buf)
14}
15
16pub(crate) fn get_all_data<P: AsRef<Path>>(file_path: P, size: usize) -> io::Result<String> {
17    let mut file = File::open(file_path.as_ref())?;
18    get_all_data_from_file(&mut file, size)
19}
20
21#[allow(clippy::useless_conversion)]
22pub(crate) fn realpath(path: &Path) -> std::path::PathBuf {
23    match std::fs::read_link(path) {
24        Ok(f) => f,
25        Err(_e) => {
26            sysinfo_debug!("failed to get real path for {:?}: {:?}", path, _e);
27            PathBuf::new()
28        }
29    }
30}
31
32/// Type used to correctly handle the `REMAINING_FILES` global.
33pub(crate) struct FileCounter(File);
34
35impl FileCounter {
36    pub(crate) fn new(f: File) -> Option<Self> {
37        unsafe {
38            if let Ok(ref mut x) = REMAINING_FILES.lock() {
39                if **x > 0 {
40                    **x -= 1;
41                    return Some(Self(f));
42                }
43                // All file descriptors we were allowed are being used.
44            }
45        }
46        None
47    }
48}
49
50impl std::ops::Deref for FileCounter {
51    type Target = File;
52
53    fn deref(&self) -> &Self::Target {
54        &self.0
55    }
56}
57impl std::ops::DerefMut for FileCounter {
58    fn deref_mut(&mut self) -> &mut Self::Target {
59        &mut self.0
60    }
61}
62
63impl Drop for FileCounter {
64    fn drop(&mut self) {
65        unsafe {
66            if let Ok(ref mut x) = crate::sys::system::REMAINING_FILES.lock() {
67                **x += 1;
68            }
69        }
70    }
71}
72
73/// This type is used in `retrieve_all_new_process_info` because we have a "parent" path and
74/// from it, we `pop`/`join` every time because it's more memory efficient than using `Path::join`.
75pub(crate) struct PathHandler(PathBuf);
76
77impl PathHandler {
78    pub(crate) fn new(path: &Path) -> Self {
79        // `path` is the "parent" for all paths which will follow so we add a fake element at
80        // the end since every `PathHandler::join` call will first call `pop` internally.
81        Self(path.join("a"))
82    }
83}
84
85pub(crate) trait PathPush {
86    fn join(&mut self, p: &str) -> &Path;
87}
88
89impl PathPush for PathHandler {
90    fn join(&mut self, p: &str) -> &Path {
91        self.0.pop();
92        self.0.push(p);
93        self.0.as_path()
94    }
95}
96
97// This implementation allows to skip one allocation that is done in `PathHandler`.
98impl PathPush for PathBuf {
99    fn join(&mut self, p: &str) -> &Path {
100        self.push(p);
101        self.as_path()
102    }
103}
104
105pub(crate) fn to_u64(v: &[u8]) -> u64 {
106    let mut x = 0;
107
108    for c in v {
109        x *= 10;
110        x += u64::from(c - b'0');
111    }
112    x
113}
114
115/// Converts a path to a NUL-terminated `Vec<u8>` suitable for use with C functions.
116pub(crate) fn to_cpath(path: &std::path::Path) -> Vec<u8> {
117    use std::{ffi::OsStr, os::unix::ffi::OsStrExt};
118
119    let path_os: &OsStr = path.as_ref();
120    let mut cpath = path_os.as_bytes().to_vec();
121    cpath.push(0);
122    cpath
123}
sysinfo/linux/utils.rs

sysinfo/linux/
utils.rs
