src/tools/procfs.rs: start helper tools to read procfs

src/tools.rs

@@ -31,6 +31,7 @@ pub mod fs;
 pub mod tty;
 pub mod signalfd;
 pub mod daemon;
+pub mod procfs;
 
 mod process_locker;
 pub use process_locker::*;

src/tools/procfs.rs

@@ -0,0 +1,48 @@
+use failure::*;
+
+use crate::tools;
+use lazy_static::lazy_static;
+use regex::Regex;
+
+pub struct ProcFsPidStat {
+    pub status: u8,
+    pub utime: u64,
+    pub stime: u64,
+    pub starttime: u64,
+    pub vsize: u64,
+    pub rss: i64,
+}
+
+pub fn read_proc_pid_stat(pid: nix::unistd::Pid) -> Result<ProcFsPidStat, Error> {
+
+    let statstr = tools::file_read_firstline(format!("/proc/{}/stat", pid))?;
+
+    lazy_static! {
+        static ref REGEX: Regex = Regex::new(r"^(?P<pid>\d+) \(.*\) (?P<status>\S) -?\d+ -?\d+ -?\d+ -?\d+ -?\d+ \d+ \d+ \d+ \d+ \d+ (?P<utime>\d+) (?P<stime>\d+) -?\d+ -?\d+ -?\d+ -?\d+ -?\d+ 0 (?P<starttime>\d+) (?P<vsize>\d+) (?P<rss>-?\d+) \d+ \d+ \d+ \d+ \d+ \d+ \d+ \d+ \d+ \d+ \d+ \d+ \d+ -?\d+ -?\d+ \d+ \d+ \d+").unwrap();
+    }
+
+    if let Some(cap) = REGEX.captures(&statstr) {
+        if pid != nix::unistd::Pid::from_raw(cap["pid"].parse::<i32>().unwrap()) {
+            bail!("unable to read pid stat for process '{}' - got wrong pid", pid);
+        }
+
+	return Ok(ProcFsPidStat {
+	    status: cap["status"].as_bytes()[0],
+	    utime: cap["utime"].parse::<u64>().unwrap(),
+	    stime: cap["stime"].parse::<u64>().unwrap(),
+	    starttime: cap["starttime"].parse::<u64>().unwrap(),
+	    vsize: cap["vsize"].parse::<u64>().unwrap(),
+	    rss: cap["rss"].parse::<i64>().unwrap() * 4096,
+	});
+
+    }
+
+    bail!("unable to read pid stat for process '{}'", pid);
+}
+
+pub fn read_proc_starttime(pid: nix::unistd::Pid) -> Result<u64, Error> {
+
+    let info = read_proc_pid_stat(pid)?;
+
+    Ok(info.starttime)
+}