Provide mem_unit and procs in sysinfo

kernel/src/process/process_table.rs

@@ -28,6 +28,11 @@ pub fn process_table_mut() -> MutexGuard<'static, ProcessTable> {
     PROCESS_TABLE.lock()
 }
 
+/// Returns the number of current processes.
+pub fn process_num() -> usize {
+    PROCESS_TABLE.lock().inner.len()
+}
+
 /// Process Table.
 pub struct ProcessTable {
     inner: BTreeMap<Pid, Arc<Process>>,

kernel/src/syscall/sysinfo.rs

@@ -3,11 +3,11 @@
 use aster_time::read_monotonic_time;
 
 use super::SyscallReturn;
-use crate::prelude::*;
+use crate::{prelude::*, process::process_table};
 
 #[derive(Debug, Default, Clone, Copy, Pod)]
 #[repr(C)]
-pub struct sysinfo {
+struct SysInfo {
     uptime: i64,     /* Seconds since boot */
     loads: [u64; 3], /* 1, 5, and 15 minute load averages */
     totalram: u64,   /* Total usable main memory size */
@@ -23,10 +23,14 @@ pub struct sysinfo {
 }
 
 pub fn sys_sysinfo(sysinfo_addr: Vaddr, ctx: &Context) -> Result<SyscallReturn> {
-    let info = sysinfo {
+    let info = SysInfo {
         uptime: read_monotonic_time().as_secs() as i64,
         totalram: crate::vm::mem_total() as u64,
         freeram: osdk_frame_allocator::load_total_free_size() as u64,
+        procs: process_table::process_num() as u16,
+        // `mem_unit` will always be 1 byte since Asterinas only supports
+        // 64-bit CPU architectures.
+        mem_unit: 1,
         ..Default::default() // TODO: add other system information
     };
     ctx.user_space().write_val(sysinfo_addr, &info)?;

test/src/syscall/gvisor/blocklists/sysinfo_test

@@ -1,2 +0,0 @@
-SysinfoTest.MemunitSet
-SysinfoTest.NumProcsSaneValue