1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174

use {
    crate::{device_id::DeviceId, error::*, sys},
    std::{
        ffi::CString,
        mem,
        os::unix::ffi::OsStrExt,
        path::PathBuf,
        str::{FromStr, SplitWhitespace},
    },
};

/// An id of a mount
pub type MountId = u32;

/// inode & blocs information given by statvfs
#[derive(Debug)]
pub struct Stats {
    pub bsize: u64,
    pub blocks: u64,
    pub bavail: u64,
    pub bfree: u64,
}

/// A mount point
#[derive(Debug)]
pub struct Mount {
    pub id: MountId,
    pub parent: MountId,
    pub dev: DeviceId,
    pub root: PathBuf,
    pub mount_point: PathBuf,
    pub fs: String,
    pub fs_type: String,
    /// true for HDD, false for SSD, None for unknown or not a disk
    pub rotational: Option<bool>,
    pub stats: Option<Stats>,
}

impl Mount {
    pub fn size(&self) -> u64 {
        self.stats.as_ref().map_or(0, |s| s.bsize * s.blocks)
    }
    pub fn available(&self) -> u64 {
        self.stats.as_ref().map_or(0, |s| s.bsize * s.bavail)
    }
    pub fn used(&self) -> u64 {
        self.size() - self.available()
    }
    pub fn use_share(&self) -> f64 {
        if self.size() == 0 {
            0.0
        } else {
            self.used() as f64 / (self.size() as f64)
        }
    }
    pub fn partition_name(&self) -> Option<String> {
        self.fs.strip_prefix("/dev/").map(String::from)
    }
    /// Something like "sda" or "sdb"
    pub fn disk_name(&self) -> Option<String> {
        // Q: Am I sure this is correct ?
        // A: Absolutely not!
        self.partition_name()
            .map(|pn| {
                pn.chars()
                    .take_while(char::is_ascii_alphabetic)
                    .collect::<String>()
            })
            .filter(|s| s.len() > 2)
    }
    pub fn disk_type(&self) -> &'static str {
        match self.rotational {
            Some(true) => "HDD",
            Some(false) => "SSD",
            None => "",
        }
    }
}

fn next<'a, 'b>(split: &'b mut SplitWhitespace<'a>) -> Result<&'a str> {
    split.next().ok_or(Error::UnexpectedFormat)
}
fn skip_until<'a, 'b>(split: &'b mut SplitWhitespace<'a>, sep: &'static str) -> Result<()> {
    Ok(loop {
        if next(split)? == sep {
            break;
        }
    })
}

impl FromStr for Mount {
    type Err = Error;
    fn from_str(line: &str) -> Result<Self> {
        // this parsing is based on `man 5 proc`
        let mut tokens = line.split_whitespace();
        let tokens = &mut tokens;
        let id = next(tokens)?.parse()?;
        let parent = next(tokens)?.parse()?;
        let dev = next(tokens)?.parse()?;
        let root = next(tokens)?.into();
        let mount_point = PathBuf::from(next(tokens)?);
        skip_until(tokens, "-")?;
        let fs_type = next(tokens)?.to_string();
        let fs = next(tokens)?.to_string();
        // we get the free/total space info in libc::statvfs
        let c_mount_point = CString::new(mount_point.as_os_str().as_bytes()).unwrap();
        let stats = unsafe {
            let mut statvfs = mem::MaybeUninit::<libc::statvfs>::uninit();
            let code = libc::statvfs(c_mount_point.as_ptr(), statvfs.as_mut_ptr());
            match code {
                0 => {
                    // good
                    let statvfs = statvfs.assume_init();
                    Some(Stats {
                        bsize: statvfs.f_bsize,
                        blocks: statvfs.f_blocks,
                        bavail: statvfs.f_bavail,
                        bfree: statvfs.f_bfree,
                    })
                }
                -1 => {
                    // the filesystem wasn't found, it's a strange one, for example a
                    // docker one
                    None
                }
                _ => {
                    // unexpected
                    return Err(Error::UnexpectedStavfsReturn {
                        code,
                        path: mount_point,
                    });
                }
            }
        };
        let mut mount = Mount {
            id,
            parent,
            dev,
            root,
            mount_point,
            fs,
            fs_type,
            rotational: None,
            stats,
        };
        // try to determine whether it's SSD or HDD
        mount.rotational = mount
            .disk_name()
            .and_then(|name| sys::read_file(&format!("/sys/block/{}/queue/rotational", name)).ok())
            .and_then(|c| {
                match c.trim().as_ref() {
                    "0" => Some(false),
                    "1" => Some(true),
                    _ => None, // should not happen today
                }
            });
        Ok(mount)
    }
}

/// read all the mount points and load basic information on them
pub fn read_all() -> Result<Vec<Mount>> {
    sys::read_file("/proc/self/mountinfo")?
        .trim()
        .split('\n')
        .map(str::parse)
        .inspect(|r| {
            if let Err(e) = r {
                eprintln!("Error while parsing a mount line: {}", e);
            }
        })
        .filter(Result::is_ok)
        .collect()
}