From 5e4946e8e43f21ea39aa087929ec80b0ff44fa5c Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Thomas=20Lov=C3=A9n?= <thomasloven@gmail.com>
Date: Tue, 21 Feb 2017 15:10:47 +0100
Subject: [PATCH] [USER] Fork syscall

---
 init/init.c               | 20 ++++++++++----------
 kernel/include/syscall.h  |  1 +
 kernel/syscall/sys_proc.c | 27 +++++++++++++++++++++++++++
 kernel/syscall/syscall.c  |  1 +
 libc/syscall_num.h        |  1 +
 libc/thread.c             | 23 +++++++++++++++++++++++
 6 files changed, 63 insertions(+), 10 deletions(-)
 create mode 100644 kernel/syscall/sys_proc.c

diff --git a/init/init.c b/init/init.c
index cd8539e..425ecc7 100644
--- a/init/init.c
+++ b/init/init.c
@@ -6,16 +6,16 @@ int main(int argc, char **argv)
   (void) argc;
   (void) argv;
 
-  char *a = malloc(0x100);
-  printf("Pointer: %p\n", a);
-  char *b = malloc(0x100);
-  printf("Pointer: %p\n", b);
-  char *c = malloc(0x10);
-  printf("Pointer: %p\n", c);
-  c[0] = 5;
-  free(a);
-  free(b);
-  free(c);
+  int num = 5;
+
+  if(fork())
+  {
+    num = 10;
+    printf("I am the parent! - %d\n", num);
+  } else {
+    num = 3;
+    printf("I am the child! - %d\n", num);
+  }
 
   for(;;);
   return 0;
diff --git a/kernel/include/syscall.h b/kernel/include/syscall.h
index 358d199..3eb2368 100644
--- a/kernel/include/syscall.h
+++ b/kernel/include/syscall.h
@@ -42,3 +42,4 @@ typedef long (*syscall_handler_t)(long num, long, long, long, long, long, long);
 
 SYSCALL_DECL(write);
 SYSCALL_DECL(brk);
+SYSCALL_DECL(fork);
diff --git a/kernel/syscall/sys_proc.c b/kernel/syscall/sys_proc.c
new file mode 100644
index 0000000..adae757
--- /dev/null
+++ b/kernel/syscall/sys_proc.c
@@ -0,0 +1,27 @@
+#include <syscall.h>
+#include <process.h>
+#include <thread.h>
+#include <scheduler.h>
+#include <string.h>
+
+SYSCALL_DEF(fork)
+{
+  SYSCALL_INIT();
+
+  // Copy process and memory space
+  process_t *p = get_current_process();
+  process_t *new = process_spawn(p);
+
+  // Copy thread
+  thread_t *th = new_thread(0, 1);
+  memcpy(&th->r, &get_current_thread()->r, sizeof(registers_t));
+
+  // Make new thread return 0
+  th->r.rax = 0;
+  process_attach(new, th);
+  scheduler_insert(th);
+
+  // Return new pid
+  return new->pid;
+
+}
diff --git a/kernel/syscall/syscall.c b/kernel/syscall/syscall.c
index 491dde2..9de60da 100644
--- a/kernel/syscall/syscall.c
+++ b/kernel/syscall/syscall.c
@@ -58,6 +58,7 @@ void syscall_init()
     SYSCALL_REGISTER(debug, SYS_DEBUG);
     SYSCALL_REGISTER(write, SYS_WRITE);
     SYSCALL_REGISTER(brk, SYS_BRK);
+    SYSCALL_REGISTER(fork, SYS_FORK);
   }
 
 }
diff --git a/libc/syscall_num.h b/libc/syscall_num.h
index c3bf36f..01da47e 100644
--- a/libc/syscall_num.h
+++ b/libc/syscall_num.h
@@ -2,4 +2,5 @@
 
 #define SYS_WRITE 0x001
 #define SYS_BRK   0x002
+#define SYS_FORK  0x003
 #define SYS_DEBUG 0x3FF
diff --git a/libc/thread.c b/libc/thread.c
index fa6ace2..7397af7 100644
--- a/libc/thread.c
+++ b/libc/thread.c
@@ -1,4 +1,8 @@
 #include "syscalls.h"
+#include "syscall_num.h"
+#include <pthread.h>
+#include <signal.h>
+long kernel_syscall(int num, ...);
 
 struct pthread *__pt;
 
@@ -19,3 +23,22 @@ SYSCALL_DEF(set_tid_address)
   SYSCALL_INIT();
   return 0;
 }
+
+SYSCALL_DEF(rt_sigprocmask)
+{
+  SYSCALL_INIT(int, how, const sigset_t *, set, sigset_t *, oldset);
+
+  return 0;
+}
+
+SYSCALL_DEF(fork)
+{
+  SYSCALL_INIT();
+  return kernel_syscall(SYS_FORK);
+}
+
+SYSCALL_DEF(gettid)
+{
+  SYSCALL_INIT();
+  return 0;
+}