Fix race condition in exec().

...also hook up sys$fstat in the syscall dispatcher.

2 files changed, 8 insertions, 2 deletions

diff --git a/Kernel/Process.cpp b/Kernel/Process.cpp
index 3acd64464f..94ab2fdd6b 100644
--- a/Kernel/Process.cpp
+++ b/Kernel/Process.cpp
@@ -363,7 +363,11 @@ int Process::do_exec(const String& path, Vector<String>&& arguments, Vector<Stri
         }
     }
 
-    InterruptDisabler disabler;
+    // We cli() manually here because we don't want to get interrupted between do_exec() and Schedule::yield().
+    // The reason is that the task redirection we've set up above will be clobbered by the timer IRQ.
+    // If we used an InterruptDisabler that sti()'d on exit, we might timer tick'd too soon in exec().
+    cli();
+
     Scheduler::prepare_to_modify_tss(*this);
 
     m_name = parts.takeLast();
diff --git a/Kernel/Syscall.cpp b/Kernel/Syscall.cpp
index f586d702ef..99e9969a9d 100644
--- a/Kernel/Syscall.cpp
+++ b/Kernel/Syscall.cpp
@@ -173,8 +173,10 @@ static dword handle(RegisterDump& regs, dword function, dword arg1, dword arg2,
         return current->sys$fcntl((int)arg1, (int)arg2, (dword)arg3);
     case Syscall::SC_ioctl:
         return current->sys$ioctl((int)arg1, (unsigned)arg2, (unsigned)arg3);
+    case Syscall::SC_fstat:
+        return current->sys$fstat((int)arg1, (Unix::stat*)arg2);
     default:
-        kprintf("<%u> int0x80: Unknown function %x requested {%x, %x, %x}\n", current->pid(), function, arg1, arg2, arg3);
+        kprintf("<%u> int0x80: Unknown function %u requested {%x, %x, %x}\n", current->pid(), function, arg1, arg2, arg3);
         break;
     }
     return 0;