From 9d1abb21f1ecd947ef21612b17d754d4799a06ae Mon Sep 17 00:00:00 2001
From: Eggert Jung <eggert.s.jung@wischhof13.de>
Date: Wed, 3 Dec 2025 06:13:57 +0100
Subject: [PATCH] getpid

---
 kernel/syscall/handler.cc  |  4 +++-
 kernel/syscall/skeleton.cc | 11 +++++++++--
 kernel/syscall/stub.h      |  8 ++++++--
 kernel/user/app1/appl.cc   |  3 +--
 4 files changed, 19 insertions(+), 7 deletions(-)

diff --git a/kernel/syscall/handler.cc b/kernel/syscall/handler.cc
index 315cb29..f88cb65 100644
--- a/kernel/syscall/handler.cc
+++ b/kernel/syscall/handler.cc
@@ -61,9 +61,11 @@ extern "C" size_t syscall_handler(size_t sysnum, size_t p1, size_t p2,
          case Syscall::ID::SEM_SIGNAL:
             Syscall::Skeleton::sem_signal(Guard::enter().vault(), p1);
             break;
+         case Syscall::ID::SYS_GETPID:
+            return Syscall::Skeleton::getpid(Guard::enter().vault());
          case Syscall::ID::SYS_EXIT:
             Syscall::Skeleton::exit(Guard::enter().vault());
- 
+            return 0;
      }
 
 	return static_cast<size_t>(-1);
diff --git a/kernel/syscall/skeleton.cc b/kernel/syscall/skeleton.cc
index cfeee82..bea3a82 100644
--- a/kernel/syscall/skeleton.cc
+++ b/kernel/syscall/skeleton.cc
@@ -9,6 +9,9 @@
 
 void *operator new(size_t, void *);
 
+#include "../user/app1/appl.h"
+extern Application apps[];
+
 namespace Syscall {
 namespace Skeleton {
 size_t test(Vault &vault, size_t p1, size_t p2, size_t p3, size_t p4,
@@ -20,8 +23,10 @@ size_t test(Vault &vault, size_t p1, size_t p2, size_t p3, size_t p4,
 }
 
 int getpid(Vault &vault) {
-	(void)vault;
-	return -1;
+	Thread *me = vault.scheduler.active();
+	unsigned id = 0;
+	while (&apps[id++] != me); // TODO find better pid source
+    return id;
 }
 
 size_t write(Vault &vault, uint32_t id, const void *buffer, size_t size, int x, int y) {
@@ -45,6 +50,8 @@ size_t write(Vault &vault, uint32_t id, const void *buffer, size_t size, int x,
 }
 
 size_t read(Vault &vault, uint32_t id, void *buf, size_t len) {
+    (void)id;
+
     size_t read_cnt = 0;
     while(read_cnt <= len){
         Key key;
diff --git a/kernel/syscall/stub.h b/kernel/syscall/stub.h
index c08ce7d..080ec37 100644
--- a/kernel/syscall/stub.h
+++ b/kernel/syscall/stub.h
@@ -14,8 +14,8 @@ enum class ID : size_t {
     SEM_DESTROY=5,
     SEM_WAIT=6,
     SEM_SIGNAL=7,
-    //SYS_GETPID=8,
-    SYS_EXIT= 9,
+    SYS_GETPID = 8,
+    SYS_EXIT = 9,
     //SYS_KILL=10
 };
 }  // namespace Syscall
@@ -59,6 +59,10 @@ extern "C" ssize_t sys_safe_call(Syscall::ID id, size_t p1, size_t p2,
   return sys_call(Syscall::ID::SEM_SIGNAL, fd, semid,0,0,0);
 }
 
+[[gnu::always_inline]] static inline int sys_getpid(){
+	return sys_call(Syscall::ID::SYS_GETPID, 0,0,0,0,0);
+}
+
 [[gnu::always_inline]] static inline void sys_exit(){
     sys_call(Syscall::ID::SYS_EXIT, 0, 0, 0, 0, 0);
 }
diff --git a/kernel/user/app1/appl.cc b/kernel/user/app1/appl.cc
index d70e5fb..d7d2119 100644
--- a/kernel/user/app1/appl.cc
+++ b/kernel/user/app1/appl.cc
@@ -20,8 +20,7 @@ void Application::action() {  // NOLINT
 
 	//sys_test(1,2,3,4,5);
 
-	unsigned id = 0;
-	while (&apps[id++] != this);
+	unsigned id = sys_getpid();
 	char text[] = "testX";
 	text[4] = 0x30+id;