use libc::{self, SI_LOAD_SHIFT}; use std::{cmp, mem}; use std::time::Duration; use crate::Result; use crate::errno::Errno; /// System info structure returned by `sysinfo`. #[derive(Copy, Clone, Debug, Eq, Hash, PartialEq)] #[repr(transparent)] pub struct SysInfo(libc::sysinfo); // The fields are c_ulong on 32-bit linux, u64 on 64-bit linux; x32's ulong is u32 #[cfg(all(target_arch = "x86_64", target_pointer_width = "32"))] type mem_blocks_t = u64; #[cfg(not(all(target_arch = "x86_64", target_pointer_width = "32")))] type mem_blocks_t = libc::c_ulong; 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: mem_blocks_t) -> u64 { units as u64 * self.0.mem_unit as u64 } } /// Returns system information. /// /// [See `sysinfo(2)`](https://man7.org/linux/man-pages/man2/sysinfo.2.html). pub fn sysinfo() -> Result { let mut info = mem::MaybeUninit::uninit(); let res = unsafe { libc::sysinfo(info.as_mut_ptr()) }; Errno::result(res).map(|_| unsafe{ SysInfo(info.assume_init()) }) }