Implement basic support for times().

The kernel now bills processes for time spent in kernelspace and userspace
separately. The accounting is forwarded to the parent process in reap().

This makes the "time" builtin in bash work.

5 files changed, 35 insertions, 0 deletions

diff --git a/Kernel/Process.cpp b/Kernel/Process.cpp
index c47aaf5def..3a1db69a26 100644
--- a/Kernel/Process.cpp
+++ b/Kernel/Process.cpp
@@ -1415,6 +1415,14 @@ int Process::reap(Process& process)
 {
     InterruptDisabler disabler;
     int exit_status = (process.m_termination_status << 8) | process.m_termination_signal;
+
+    if (process.ppid()) {
+        auto* parent = Process::from_pid(process.ppid());
+        ASSERT(parent);
+        parent->m_ticks_in_user_for_dead_children += process.m_ticks_in_user + process.m_ticks_in_user_for_dead_children;
+        parent->m_ticks_in_kernel_for_dead_children += process.m_ticks_in_kernel + process.m_ticks_in_kernel_for_dead_children;
+    }
+
     dbgprintf("reap: %s(%u) {%s}\n", process.name().characters(), process.pid(), toString(process.state()));
     ASSERT(process.state() == Dead);
     g_processes->remove(&process);
@@ -1763,3 +1771,14 @@ int Process::sys$mkdir(const char* pathname, mode_t mode)
         return error;
     return 0;
 }
+
+Unix::clock_t Process::sys$times(Unix::tms* times)
+{
+    if (!validate_write_typed(times))
+        return -EFAULT;
+    times->tms_utime = m_ticks_in_user;
+    times->tms_stime = m_ticks_in_kernel;
+    times->tms_cutime = m_ticks_in_user_for_dead_children;
+    times->tms_cstime = m_ticks_in_kernel_for_dead_children;
+    return 0;
+}
diff --git a/Kernel/Process.h b/Kernel/Process.h
index 56c829d7dd..5b56e32039 100644
--- a/Kernel/Process.h
+++ b/Kernel/Process.h
@@ -172,6 +172,7 @@ public:
     int sys$fcntl(int fd, int cmd, dword extra_arg);
     int sys$ioctl(int fd, unsigned request, unsigned arg);
     int sys$mkdir(const char* pathname, mode_t mode);
+    Unix::clock_t sys$times(Unix::tms*);
 
     static void initialize();
 
@@ -187,6 +188,12 @@ public:
     void did_schedule() { ++m_timesScheduled; }
     dword timesScheduled() const { return m_timesScheduled; }
 
+    dword m_ticks_in_user { 0 };
+    dword m_ticks_in_kernel { 0 };
+
+    dword m_ticks_in_user_for_dead_children { 0 };
+    dword m_ticks_in_kernel_for_dead_children { 0 };
+
     pid_t waitee_pid() const { return m_waitee_pid; }
 
     dword framePtr() const { return m_tss.ebp; }
diff --git a/Kernel/Scheduler.cpp b/Kernel/Scheduler.cpp
index 56fe2ddf7f..88156eb9bb 100644
--- a/Kernel/Scheduler.cpp
+++ b/Kernel/Scheduler.cpp
@@ -181,6 +181,12 @@ bool Scheduler::context_switch(Process& process)
     process.set_ticks_left(time_slice);
     process.did_schedule();
 
+    if (process.tss().cs & 3) {
+        ++process.m_ticks_in_user;
+    } else {
+        ++process.m_ticks_in_kernel;
+    }
+
     if (current == &process)
         return false;
 
diff --git a/Kernel/Syscall.cpp b/Kernel/Syscall.cpp
index 6a4711191f..d5864406c8 100644
--- a/Kernel/Syscall.cpp
+++ b/Kernel/Syscall.cpp
@@ -175,6 +175,8 @@ static dword handle(RegisterDump& regs, dword function, dword arg1, dword arg2,
         return current->sys$fstat((int)arg1, (Unix::stat*)arg2);
     case Syscall::SC_mkdir:
         return current->sys$mkdir((const char*)arg1, (mode_t)arg2);
+    case Syscall::SC_times:
+        return current->sys$times((Unix::tms*)arg1);
     default:
         kprintf("<%u> int0x80: Unknown function %u requested {%x, %x, %x}\n", current->pid(), function, arg1, arg2, arg3);
         break;
diff --git a/Kernel/Syscall.h b/Kernel/Syscall.h
index 18fdf5d9d7..81717dbda6 100644
--- a/Kernel/Syscall.h
+++ b/Kernel/Syscall.h
@@ -63,6 +63,7 @@
     __ENUMERATE_SYSCALL(fcntl) \
     __ENUMERATE_SYSCALL(ioctl) \
     __ENUMERATE_SYSCALL(mkdir) \
+    __ENUMERATE_SYSCALL(times) \
 
 
 #define DO_SYSCALL_A0(function) Syscall::invoke((dword)(function))