From 4cf222a5bb1b7af28287b41e8bbb7c7cee6caf99 Mon Sep 17 00:00:00 2001
From: "Justin C. Miller" <justin@justin.cm>
Date: Sun, 19 Jul 2020 17:15:36 -0700
Subject: [PATCH] [kernel] Remove getpid and fork system calls

The getpid and fork system calls were stubbed out previously, this
commit removes them and adds process_koid as a getpid replacement.
---
 src/drivers/nulldrv/main.cpp    | 10 +++------
 src/drivers/nulldrv/main.s      | 23 +++++---------------
 src/kernel/syscalls.inc         |  9 ++++----
 src/kernel/syscalls/process.cpp | 38 ++++++---------------------------
 4 files changed, 19 insertions(+), 61 deletions(-)

diff --git a/src/drivers/nulldrv/main.cpp b/src/drivers/nulldrv/main.cpp
index 86da144..2c552af 100644
--- a/src/drivers/nulldrv/main.cpp
+++ b/src/drivers/nulldrv/main.cpp
@@ -5,8 +5,7 @@
 #include "j6/errors.h"
 
 extern "C" {
-	j6_status_t getpid(uint64_t *);
-	j6_status_t fork(uint64_t *);
+	j6_status_t get_process_koid(j6_koid_t *koid);
 	j6_status_t sleep(uint64_t til);
 	j6_status_t debug();
 	j6_status_t message(const char *msg);
@@ -20,17 +19,14 @@ main(int argc, const char **argv)
 {
 	uint64_t pid = 0;
 	uint64_t child = 0;
+	j6_koid_t process = 0;
 
-	j6_status_t result = fork(&child);
+	j6_status_t result = get_process_koid(&process);
 	if (result != j6_status_ok)
 		return result;
 
 	message("hello from nulldrv!");
 
-	result = getpid(&pid);
-	if (result != j6_status_ok)
-		return result;
-
 	for (int i = 1; i < 5; ++i)
 		sleep(i*10);
 
diff --git a/src/drivers/nulldrv/main.s b/src/drivers/nulldrv/main.s
index 73a5300..dd760dc 100644
--- a/src/drivers/nulldrv/main.s
+++ b/src/drivers/nulldrv/main.s
@@ -6,13 +6,13 @@ extern main
 extern exit
 
 section .text
-global getpid
-getpid:
+global get_process_koid
+get_process_koid:
 	push rbp
 	mov rbp, rsp
 
 	; address of out var should already be in rdi
-	mov rax, 0x13  ; getpid syscall
+	mov rax, 0x10  ; getpid syscall
 	syscall        ; result is now already in rax, so just return
 
 	pop rbp
@@ -34,32 +34,19 @@ sleep:
 	push rbp
 	mov rbp, rsp
 
-	mov rax, 0x16  ; sleep syscall
+	mov rax, 0x14  ; sleep syscall
 	syscall
 
 	pop rbp
 	ret
 
-global fork
-fork:
-	push rbp
-	mov rbp, rsp
-
-	; address of out var should already be in rdi
-	mov rax, 0x12
-	syscall    ; result left in rax
-
-	pop rbp
-	ret
-	
-
 global message
 message:
 	push rbp
 	mov rbp, rsp
 
 	; message should already be in rdi
-	mov rax, 0x14
+	mov rax, 0x12
 	syscall
 
 	pop rbp
diff --git a/src/kernel/syscalls.inc b/src/kernel/syscalls.inc
index f716e7e..892ed5b 100644
--- a/src/kernel/syscalls.inc
+++ b/src/kernel/syscalls.inc
@@ -1,9 +1,8 @@
 SYSCALL(0x00, object_noop,      void)
 SYSCALL(0x01, object_wait,      j6_handle_t, j6_signal_t, j6_signal_t *)
 
+SYSCALL(0x10, process_koid,     j6_koid_t *)
 SYSCALL(0x11, process_exit,     int64_t)
-SYSCALL(0x12, process_fork,     uint32_t*)
-SYSCALL(0x13, process_getpid,   uint32_t*)
-SYSCALL(0x14, process_log,      const char *)
-SYSCALL(0x15, process_pause,    void)
-SYSCALL(0x16, process_sleep,    uint64_t)
+SYSCALL(0x12, process_log,      const char *)
+SYSCALL(0x13, process_pause,    void)
+SYSCALL(0x14, process_sleep,    uint64_t)
diff --git a/src/kernel/syscalls/process.cpp b/src/kernel/syscalls/process.cpp
index fbbf294..d58a06d 100644
--- a/src/kernel/syscalls/process.cpp
+++ b/src/kernel/syscalls/process.cpp
@@ -1,6 +1,8 @@
 #include "j6/errors.h"
 #include "j6/types.h"
 
+#include "objects/process.h"
+
 #include "log.h"
 #include "scheduler.h"
 
@@ -21,43 +23,20 @@ process_exit(int64_t status)
 	return j6_err_unexpected;
 }
 
-/*
 j6_status_t
-process_fork(pid_t *pid)
+process_koid(j6_koid_t *koid)
 {
-	if (pid == nullptr) {
+	if (koid == nullptr) {
 		return j6_err_invalid_arg;
 	}
 
-	auto &s = scheduler::get();
-	auto *p = s.current();
-	pid_t ppid = p->pid;
-
-	log::debug(logs::syscall, "Process %d calling fork(%016llx)", ppid, pid);
-
-	*pid = p->fork();
-
-	p = s.current();
-	log::debug(logs::syscall, "Process %d's fork: returning %d from process %d", ppid, *pid, p->pid);
+	TCB *tcb = scheduler::get().current();
+	process &p = thread::from_tcb(tcb)->parent();
 
+	*koid = p.koid();
 	return j6_status_ok;
 }
 
-j6_status_t
-process_getpid(pid_t *pid)
-{
-	if (pid == nullptr) {
-		return j6_err_invalid_arg;
-	}
-
-	auto &s = scheduler::get();
-	auto *p = s.current();
-
-	*pid = p->pid;
-	return j6_status_ok;
-}
-*/
-
 j6_status_t
 process_log(const char *message)
 {
@@ -72,9 +51,6 @@ process_log(const char *message)
 	return j6_status_ok;
 }
 
-j6_status_t process_fork(uint32_t *pid) { *pid = 5; return process_log("CALLED FORK"); }
-j6_status_t process_getpid(uint32_t *pid) { *pid = 0; return process_log("CALLED GETPID"); }
-
 j6_status_t
 process_pause()
 {