kernel: Add the getrusage() system call

kernel/CMakeLists.txt

@@ -39,6 +39,7 @@ set(SOURCES
     src/sys/link.cpp
     src/sys/uname.cpp
     src/sys/mount.cpp
+    src/sys/resource.cpp
     src/fs/VFS.cpp
     src/fs/Pipe.cpp
     src/fs/Mount.cpp

kernel/src/sys/pstat.cpp

@@ -28,9 +28,9 @@ Result<u64> sys_pstat(Registers*, SyscallArgs args)
     proc.ps_egid = thread->auth.egid;
     proc.ps_state = (int)thread->state;
     proc.ps_flags = thread->is_kernel ? PS_FLAG_KRNL : 0;
-    set_timespec(proc.ps_time, thread->ticks);
+    set_timespec(proc.ps_time, thread->user_ticks_self + thread->kernel_ticks_self);
-    set_timespec(proc.ps_ktime, thread->ticks_in_kernel);
+    set_timespec(proc.ps_ktime, thread->kernel_ticks_self);
-    set_timespec(proc.ps_utime, thread->ticks_in_user);
+    set_timespec(proc.ps_utime, thread->kernel_ticks_children);
     strlcpy(proc.ps_name, thread->name.chars(), sizeof(proc.ps_name));
     strlcpy(proc.ps_cwd, thread->current_directory_path.is_empty() ? "/" : thread->current_directory_path.chars(),
             sizeof(proc.ps_cwd));

kernel/src/sys/resource.cpp

@@ -0,0 +1,32 @@
+#include "memory/MemoryManager.h"
+#include "sys/Syscall.h"
+#include "thread/Scheduler.h"
+#include <bits/rusage.h>
+
+static void ticks_to_rusage(struct rusage* ru, u64 sticks, u64 uticks)
+{
+    ru->ru_stime.tv_sec = sticks / 1000;
+    ru->ru_stime.tv_usec = (sticks % 1000) * 1000;
+    ru->ru_utime.tv_sec = uticks / 1000;
+    ru->ru_utime.tv_usec = (uticks % 1000) * 1000;
+}
+
+Result<u64> sys_getrusage(Registers*, SyscallArgs args)
+{
+    int who = (int)args[0];
+    struct rusage* ru = (struct rusage*)args[1];
+
+    auto* current = Scheduler::current();
+
+    struct rusage kru;
+    switch (who)
+    {
+    case RUSAGE_SELF: ticks_to_rusage(&kru, current->kernel_ticks_self, current->user_ticks_self); break;
+    case RUSAGE_CHILDREN: ticks_to_rusage(&kru, current->kernel_ticks_children, current->user_ticks_children); break;
+    default: return err(EINVAL);
+    }
+
+    if (!MemoryManager::copy_to_user_typed(ru, &kru)) return err(EFAULT);
+
+    return 0;
+}

kernel/src/sys/waitpid.cpp

@@ -50,6 +50,9 @@ Result<u64> sys_waitpid(Registers*, SyscallArgs args)
     int status = (int)thread->status;
     u64 id = thread->id;
 
+    current->user_ticks_children += thread->user_ticks_self;
+    current->kernel_ticks_children += thread->kernel_ticks_self;
+
     thread->state = ThreadState::Dying;
     Scheduler::signal_reap_thread();
 

kernel/src/thread/Scheduler.cpp

@@ -261,11 +261,9 @@ namespace Scheduler
     {
         CPU::disable_interrupts();
 
-        g_current->ticks++;
+        if (is_in_kernel(regs)) g_current->kernel_ticks_self++;
-
-        if (is_in_kernel(regs)) g_current->ticks_in_kernel++;
         else
-            g_current->ticks_in_user++;
+            g_current->user_ticks_self++;
 
         g_current->ticks_left--;
 
@@ -342,11 +340,11 @@ namespace Scheduler
 
         for (const auto* thread : g_threads)
         {
-            kdbgln("%p %c [%-20s] %4zu, parent = (%-18p,%zu), state = %d, ticks: (t:%04zu,k:%04zu,u:%04zu), status = "
+            kdbgln("%p %c [%-20s] %4zu, parent = (%-18p,%zu), state = %d, ticks: (k:%04zu,u:%04zu), status = "
                    "%d, cwd = %s",
                    thread, thread->is_kernel ? 'k' : 'u', thread->name.chars(), thread->id, thread->parent,
-                   thread->parent ? thread->parent->id : 0, (int)thread->state, thread->ticks, thread->ticks_in_kernel,
+                   thread->parent ? thread->parent->id : 0, (int)thread->state, thread->kernel_ticks_self,
-                   thread->ticks_in_user, thread->status,
+                   thread->user_ticks_self, thread->status,
                    thread->current_directory_path.is_empty() ? "/" : thread->current_directory_path.chars());
         }
 

kernel/src/thread/Thread.h

@@ -59,9 +59,10 @@ struct Thread : public LinkedListNode<Thread>
 
     Credentials auth;
 
-    u64 ticks = 0;
+    u64 user_ticks_self = 0;
-    u64 ticks_in_user = 0;
+    u64 kernel_ticks_self = 0;
-    u64 ticks_in_kernel = 0;
+    u64 user_ticks_children = 0;
+    u64 kernel_ticks_children = 0;
 
     u64 ticks_left;
     u64 sleep_ticks_left;

libc/include/bits/rusage.h

@@ -0,0 +1,17 @@
+/* bits/rusage.h: The rusage structure. */
+
+#ifndef _BITS_RUSAGE_H
+#define _BITS_RUSAGE_H
+
+#include <bits/timespec.h>
+
+struct rusage
+{
+    struct timeval ru_utime;
+    struct timeval ru_stime;
+};
+
+#define RUSAGE_SELF 0
+#define RUSAGE_CHILDREN 1
+
+#endif

libluna/include/luna/Syscall.h

@@ -5,7 +5,7 @@
         _e(lseek) _e(mkdir) _e(execve) _e(fork) _e(waitpid) _e(getppid) _e(fcntl) _e(getdents) _e(getuid) _e(geteuid)  \
             _e(getgid) _e(getegid) _e(setuid) _e(setgid) _e(seteuid) _e(setegid) _e(fchmodat) _e(fchownat) _e(ioctl)   \
                 _e(fstatat) _e(chdir) _e(getcwd) _e(unlinkat) _e(uname) _e(sethostname) _e(dup2) _e(pipe) _e(mount)    \
-                    _e(umount) _e(pstat)
+                    _e(umount) _e(pstat) _e(getrusage)
 
 enum Syscalls
 {