use libc::{self, SI_LOAD_SHIFT}; use std::{cmp, mem}; use std::time::Duration; use Result; use errno::Errno; /// System info structure returned by `sysinfo`. #[derive(Copy, Clone)] #[allow(missing_debug_implementations)] // libc::sysinfo doesn't impl Debug pub struct SysInfo(libc::sysinfo); impl SysInfo { /// Returns the load average tuple. /// /// The returned values represent the load average over time intervals of /// 1, 5, and 15 minutes, respectively. pub fn load_average(&self) -> (f64, f64, f64) { ( self.0.loads[0] as f64 / (1 << SI_LOAD_SHIFT) as f64, self.0.loads[1] as f64 / (1 << SI_LOAD_SHIFT) as f64, self.0.loads[2] as f64 / (1 << SI_LOAD_SHIFT) as f64, ) } /// Returns the time since system boot. pub fn uptime(&self) -> Duration { // Truncate negative values to 0 Duration::from_secs(cmp::max(self.0.uptime, 0) as u64) } /// Current number of processes. pub fn process_count(&self) -> u16 { self.0.procs } /// Returns the amount of swap memory in Bytes. pub fn swap_total(&self) -> u64 { self.scale_mem(self.0.totalswap) } /// Returns the amount of unused swap memory in Bytes. pub fn swap_free(&self) -> u64 { self.scale_mem(self.0.freeswap) } /// Returns the total amount of installed RAM in Bytes. pub fn ram_total(&self) -> u64 { self.scale_mem(self.0.totalram) } /// Returns the amount of completely unused RAM in Bytes. /// /// "Unused" in this context means that the RAM in neither actively used by /// programs, nor by the operating system as disk cache or buffer. It is /// "wasted" RAM since it currently serves no purpose. pub fn ram_unused(&self) -> u64 { self.scale_mem(self.0.freeram) } fn scale_mem(&self, units: libc::c_ulong) -> u64 { units as u64 * self.0.mem_unit as u64 } } /// Returns system information. /// /// [See `sysinfo(2)`](http://man7.org/linux/man-pages/man2/sysinfo.2.html). pub fn sysinfo() -> Result { let mut info: libc::sysinfo = unsafe { mem::uninitialized() }; let res = unsafe { libc::sysinfo(&mut info) }; Errno::result(res).map(|_| SysInfo(info)) }