Add support for /dev/devices

procfs-core/src/devices.rs

@@ -0,0 +1,192 @@
+use std::io::BufRead;
+
+use super::ProcResult;
+use std::str::FromStr;
+
+#[cfg(feature = "serde1")]
+use serde::{Deserialize, Serialize};
+
+/// Device entries under `/proc/devices`
+#[derive(Debug, Clone)]
+#[cfg_attr(feature = "serde1", derive(Serialize, Deserialize))]
+pub struct Devices {
+    /// Character devices
+    pub char_devices: Vec<CharDeviceEntry>,
+    /// Block devices, which can be empty if the kernel doesn't support block devices (without `CONFIG_BLOCK`)
+    pub block_devices: Vec<BlockDeviceEntry>,
+}
+
+/// A charcter device entry under `/proc/devices`
+#[derive(Debug, Clone)]
+#[cfg_attr(feature = "serde1", derive(Serialize, Deserialize))]
+pub struct CharDeviceEntry {
+    /// Device major number
+    pub major: u32,
+    /// Device name
+    pub name: String,
+}
+
+/// A block device entry under `/proc/devices`
+#[derive(Debug, Clone)]
+#[cfg_attr(feature = "serde1", derive(Serialize, Deserialize))]
+pub struct BlockDeviceEntry {
+    /// Device major number
+    pub major: i32,
+    /// Device name
+    pub name: String,
+}
+
+impl super::FromBufRead for Devices {
+    fn from_buf_read<R: BufRead>(r: R) -> ProcResult<Self> {
+        enum State {
+            Char,
+            Block,
+        }
+        let mut state = State::Char; // Always start with char devices
+        let mut devices = Devices {
+            char_devices: vec![],
+            block_devices: vec![],
+        };
+
+        for line in r.lines() {
+            let line = expect!(line);
+
+            if line.is_empty() {
+                continue;
+            } else if line.starts_with("Character devices:") {
+                state = State::Char;
+                continue;
+            } else if line.starts_with("Block devices:") {
+                state = State::Block;
+                continue;
+            }
+
+            let mut s = line.split_whitespace();
+
+            match state {
+                State::Char => {
+                    let major = expect!(u32::from_str(expect!(s.next())));
+                    let name = expect!(s.next()).to_string();
+
+                    let char_device_entry = CharDeviceEntry { major, name };
+
+                    devices.char_devices.push(char_device_entry);
+                }
+                State::Block => {
+                    let major = expect!(i32::from_str(expect!(s.next())));
+                    let name = expect!(s.next()).to_string();
+
+                    let block_device_entry = BlockDeviceEntry { major, name };
+
+                    devices.block_devices.push(block_device_entry);
+                }
+            }
+        }
+
+        Ok(devices)
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    #[test]
+    fn test_devices() {
+        use crate::FromBufRead;
+        use std::io::Cursor;
+
+        let s = "Character devices:
+  1 mem
+  4 /dev/vc/0
+  4 tty
+  4 ttyS
+  5 /dev/tty
+  5 /dev/console
+  5 /dev/ptmx
+  7 vcs
+ 10 misc
+ 13 input
+ 29 fb
+ 90 mtd
+136 pts
+180 usb
+188 ttyUSB
+189 usb_device
+
+Block devices:
+  7 loop
+  8 sd
+ 65 sd
+ 71 sd
+128 sd
+135 sd
+254 device-mapper
+259 blkext
+";
+
+        let cursor = Cursor::new(s);
+        let devices = Devices::from_buf_read(cursor).unwrap();
+        let (chrs, blks) = (devices.char_devices, devices.block_devices);
+
+        assert_eq!(chrs.len(), 16);
+
+        assert_eq!(chrs[1].major, 4);
+        assert_eq!(chrs[1].name, "/dev/vc/0");
+
+        assert_eq!(chrs[8].major, 10);
+        assert_eq!(chrs[8].name, "misc");
+
+        assert_eq!(chrs[15].major, 189);
+        assert_eq!(chrs[15].name, "usb_device");
+
+        assert_eq!(blks.len(), 8);
+
+        assert_eq!(blks[0].major, 7);
+        assert_eq!(blks[0].name, "loop");
+
+        assert_eq!(blks[7].major, 259);
+        assert_eq!(blks[7].name, "blkext");
+    }
+
+    #[test]
+    fn test_devices_without_block() {
+        use crate::FromBufRead;
+        use std::io::Cursor;
+
+        let s = "Character devices:
+  1 mem
+  4 /dev/vc/0
+  4 tty
+  4 ttyS
+  5 /dev/tty
+  5 /dev/console
+  5 /dev/ptmx
+  7 vcs
+ 10 misc
+ 13 input
+ 29 fb
+ 90 mtd
+136 pts
+180 usb
+188 ttyUSB
+189 usb_device
+";
+
+        let cursor = Cursor::new(s);
+        let devices = Devices::from_buf_read(cursor).unwrap();
+        let (chrs, blks) = (devices.char_devices, devices.block_devices);
+
+        assert_eq!(chrs.len(), 16);
+
+        assert_eq!(chrs[1].major, 4);
+        assert_eq!(chrs[1].name, "/dev/vc/0");
+
+        assert_eq!(chrs[8].major, 10);
+        assert_eq!(chrs[8].name, "misc");
+
+        assert_eq!(chrs[15].major, 189);
+        assert_eq!(chrs[15].name, "usb_device");
+
+        assert_eq!(blks.len(), 0);
+    }
+}

procfs-core/src/lib.rs

@@ -354,6 +354,9 @@ pub use cpuinfo::*;
 mod crypto;
 pub use crypto::*;
 
+mod devices;
+pub use devices::*;
+
 mod diskstats;
 pub use diskstats::*;
 

procfs/src/lib.rs

@@ -434,6 +434,10 @@ impl Current for CpuInfo {
     const PATH: &'static str = "/proc/cpuinfo";
 }
 
+impl Current for Devices {
+    const PATH: &'static str = "/proc/devices";
+}
+
 impl Current for DiskStats {
     const PATH: &'static str = "/proc/diskstats";
 }
@@ -685,6 +689,12 @@ mod tests {
         //assert_eq!(info.num_cores(), 8);
     }
 
+    #[test]
+    fn test_devices() {
+        let devices = Devices::current().unwrap();
+        println!("{:#?}", devices);
+    }
+
     #[test]
     fn test_diskstats() {
         for disk in super::diskstats().unwrap() {

support.md

@@ -71,7 +71,7 @@ This is an approximate list of all the files under the `/proc` mount, and an ind
 * [ ] `/proc/config.gz`
 * [ ] `/proc/crypto`
 * [ ] `/proc/cpuinfo`
-* [ ] `/proc/devices`
+* [x] `/proc/devices`
 * [x] `/proc/diskstats`
 * [ ] `/proc/dma`
 * [ ] `/proc/driver`