1use libc::{self, SI_LOAD_SHIFT}; 2use std::time::Duration; 3use std::{cmp, mem}; 4 5use crate::errno::Errno; 6use crate::Result; 7 8/// System info structure returned by `sysinfo`. 9#[derive(Copy, Clone, Debug, Eq, Hash, PartialEq)] 10#[repr(transparent)] 11pub struct SysInfo(libc::sysinfo); 12 13// The fields are c_ulong on 32-bit linux, u64 on 64-bit linux; x32's ulong is u32 14#[cfg(all(target_arch = "x86_64", target_pointer_width = "32"))] 15type mem_blocks_t = u64; 16#[cfg(not(all(target_arch = "x86_64", target_pointer_width = "32")))] 17type mem_blocks_t = libc::c_ulong; 18 19impl SysInfo { 20 /// Returns the load average tuple. 21 /// 22 /// The returned values represent the load average over time intervals of 23 /// 1, 5, and 15 minutes, respectively. 24 pub fn load_average(&self) -> (f64, f64, f64) { 25 ( 26 self.0.loads[0] as f64 / (1 << SI_LOAD_SHIFT) as f64, 27 self.0.loads[1] as f64 / (1 << SI_LOAD_SHIFT) as f64, 28 self.0.loads[2] as f64 / (1 << SI_LOAD_SHIFT) as f64, 29 ) 30 } 31 32 /// Returns the time since system boot. 33 // The cast is not unnecessary on all platforms. 34 #[allow(clippy::unnecessary_cast)] 35 pub fn uptime(&self) -> Duration { 36 // Truncate negative values to 0 37 Duration::from_secs(cmp::max(self.0.uptime, 0) as u64) 38 } 39 40 /// Current number of processes. 41 pub fn process_count(&self) -> u16 { 42 self.0.procs 43 } 44 45 /// Returns the amount of swap memory in Bytes. 46 pub fn swap_total(&self) -> u64 { 47 self.scale_mem(self.0.totalswap) 48 } 49 50 /// Returns the amount of unused swap memory in Bytes. 51 pub fn swap_free(&self) -> u64 { 52 self.scale_mem(self.0.freeswap) 53 } 54 55 /// Returns the total amount of installed RAM in Bytes. 56 pub fn ram_total(&self) -> u64 { 57 self.scale_mem(self.0.totalram) 58 } 59 60 /// Returns the amount of completely unused RAM in Bytes. 61 /// 62 /// "Unused" in this context means that the RAM in neither actively used by 63 /// programs, nor by the operating system as disk cache or buffer. It is 64 /// "wasted" RAM since it currently serves no purpose. 65 pub fn ram_unused(&self) -> u64 { 66 self.scale_mem(self.0.freeram) 67 } 68 69 // The cast is not unnecessary on all platforms. 70 #[allow(clippy::unnecessary_cast)] 71 fn scale_mem(&self, units: mem_blocks_t) -> u64 { 72 units as u64 * self.0.mem_unit as u64 73 } 74} 75 76/// Returns system information. 77/// 78/// [See `sysinfo(2)`](https://man7.org/linux/man-pages/man2/sysinfo.2.html). 79pub fn sysinfo() -> Result<SysInfo> { 80 let mut info = mem::MaybeUninit::uninit(); 81 let res = unsafe { libc::sysinfo(info.as_mut_ptr()) }; 82 Errno::result(res).map(|_| unsafe { SysInfo(info.assume_init()) }) 83} 84