kernel: add sys mem resource

src/scheme/sys/mem.rs

@@ -0,0 +1,20 @@
+use crate::{memory, sync::CleanLockToken, syscall::error::Result};
+use alloc::vec::Vec;
+
+pub fn resource(_token: &mut CleanLockToken) -> Result<Vec<u8>> {
+    let total_kib = memory::total_frames() as u64 * memory::PAGE_SIZE as u64 / 1024;
+    let free_kib = memory::free_frames() as u64 * memory::PAGE_SIZE as u64 / 1024;
+
+    Ok(format!(
+        "MemTotal: {} kB\n\
+MemFree: {} kB\n\
+MemAvailable: {} kB\n\
+Buffers: 0 kB\n\
+Cached: 0 kB\n\
+SwapTotal: 0 kB\n\
+SwapFree: 0 kB\n\
+SwapCached: 0 kB\n",
+        total_kib, free_kib, free_kib
+    )
+    .into_bytes())
+}

src/scheme/sys/mod.rs

@@ -34,6 +34,7 @@ mod fdstat;
 mod iostat;
 mod irq;
 mod log;
+mod mem;
 mod msr;
 mod stat;
 mod syscall;
@@ -110,6 +111,7 @@ const FILES: &[(&str, Kind)] = &[
     ("iostat", Rd(iostat::resource)),
     ("irq", Rd(irq::resource)),
     ("log", Rd(log::resource)),
+    ("mem", Rd(mem::resource)),
     ("syscall", Rd(syscall::resource)),
     ("uname", Rd(uname::resource)),
     ("env", Rd(|_| Ok(Vec::from(crate::startup::init_env())))),