From d8331335ff1720ce28eba45afe1a02814b38b033 Mon Sep 17 00:00:00 2001
From: Michal Idziorek <m.i@gmx.at>
Date: Mon, 1 Dec 2014 21:49:22 +0100
Subject: finally implemented fork() syscall

---
 kernel/task.c | 124 +++++++++++++++++-----------------------------------------
 1 file changed, 36 insertions(+), 88 deletions(-)

(limited to 'kernel/task.c')

diff --git a/kernel/task.c b/kernel/task.c
index c9554b5..1780b77 100644
--- a/kernel/task.c
+++ b/kernel/task.c
@@ -21,57 +21,32 @@ static volatile int current_task=-2;
 
 static volatile struct task_list_struct
 {
+    int parent;
     bool active;
     uint32_t esp; // stack pointer of the task;
     uint32_t vmem; // number of virtual memory table to switch to
     
-}task_list[MAX_TASKS];
+}volatile task_list[MAX_TASKS];
 
-
-void task_create(int pid,void(*thread)())
+int add_task(uint32_t esp, uint32_t vmem)
 {
-    task_list[pid].vmem=vmem_new_space_dir(); 
-    if(pid==0)x86_set_pdbr(0x0D08000);
-    if(pid==1)x86_set_pdbr(0x150E000);
-
-     unsigned int *stack;
-
-
-    task_list[pid].esp = 0x8248000-4095;
-    stack = (unsigned int*)task_list[pid].esp+4095; //This makes a pointer to the stack for us
-
-    log(FOOLOS_MODULE_NAME,FOOLOS_LOG_INFO,"new task: stack: 0x%08X  thread: 0x%08X", stack, thread);
-
- //First, this stuff is pushed by the processor
- *--stack = 0x0202; //This is EFLAGS
- *--stack = 0x08;   //This is CS, our code segment
- *--stack = (uint32_t)thread; //This is EIP
- 
- //Next, the stuff pushed by 'pusha'
- *--stack = 0; //EDI
- *--stack = 0; //ESI
- *--stack = 0; //EBP
- *--stack = 0; //Just an offset, no value
- *--stack = 0; //EBX
- *--stack = 0; //EDX
- *--stack = 0; //ECX
- *--stack = 0; //EAX
- 
- //Now these are the data segments pushed by the IRQ handler
- /*
- *--stack = 0x10; //DS
- *--stack = 0x10; //ES
- *--stack = 0x10; //FS
- *--stack = 0x10; //GS
- */
 
-    
-    task_list[pid].esp = (uint32_t)stack; //Update the stack pointer
-    task_list[pid].active=true;
+    for(int i=0;i<MAX_TASKS;i++)
+    {
+	if(task_list[i].active!=true)
+	{
 
-    x86_set_pdbr(0x0502000);
+	    task_list[i].parent=current_task;
+	    task_list[i].vmem=vmem;
+	    task_list[i].esp=esp;
+	    task_list[i].active=true;
 
-};
+	    return i;
+	}
+    }
+
+    panic(FOOLOS_MODULE_NAME,"out of task slots!");
+}
 
 // this gets called by our clock interrupt regularly!
 uint32_t task_switch_next(uint32_t oldesp)
@@ -79,7 +54,8 @@ uint32_t task_switch_next(uint32_t oldesp)
     timer_tick();
 
     if(current_task==-2)return oldesp;
-    if(current_task!=-1)task_list[current_task].esp=oldesp;
+    
+    task_list[current_task].esp=oldesp;
     
     for(int i=0;i<MAX_TASKS;i++)
     {
@@ -87,12 +63,10 @@ uint32_t task_switch_next(uint32_t oldesp)
 
 	if(task_list[pid].active)
 	{
-	    log(FOOLOS_MODULE_NAME,FOOLOS_LOG_INFO,"switch from %d to pid: %d (0x%08X) vmem: %d ", current_task,pid,task_list[pid].esp,task_list[pid].vmem);
+	  //  log(FOOLOS_MODULE_NAME,FOOLOS_LOG_INFO,"switch from %d to pid: %d (0x%08X) vmem: %d ", current_task,pid,task_list[pid].esp,task_list[pid].vmem);
 	    current_task=pid;
 
-	    if(pid==0)x86_set_pdbr(0x0D08000);
-	    if(pid==1)x86_set_pdbr(0x150E000);
-	    
+	    vmem_set_dir(task_list[pid].vmem);
 	    return task_list[pid].esp;
 	}
 
@@ -103,55 +77,29 @@ uint32_t task_switch_next(uint32_t oldesp)
 }
 
 
-// task testing //
-volatile void test1()
+uint32_t task_fork(uint32_t oldesp)
+{ 
+    return add_task(oldesp,vmem_new_space_dir());
+}
+
+// init task (root of all other tasks / processes) //
+void task_init()
 {
+    // this is our main task on slot 0 
+    task_list[0].active=true;
+    task_list[0].vmem=0;
+    task_list[0].esp = 0; // will be set by next task_switch_next() call.
+    current_task=0;
 
-    
-    
     static char *argv[]={"/bin/foolshell",NULL};
     static char *env[]={"PATH=/bin","PWD=/home/miguel","PS1=$ ",NULL};
-    syscall_execve("/bin/task1",argv,env); 
-    
-
-    while(1)
-    {
-	syscall_write(1,">",1);
-    }
+    syscall_execve("/bin/init",argv,env); 
 }
 
-volatile void test2()
-{
-    
-    static char *argv[]={"/bin/foolshell",NULL};
-    static char *env[]={"PATH=/bin","PWD=/home/miguel","PS1=$ ",NULL};
-    syscall_execve("/bin/task2",argv,env); 
-    
-    
 
-    while(1)
-    {
-	for(int i='a';i<'z';i++)
-	{
-        	syscall_write(1,&i,1);
-	}
-    }
-    
-}
-volatile void test3()
-{
-    while(1)
-    {
-	syscall_write(1," ",1);
-    }
-    
-}
-void task_init()
+int task_get_current_pid()
 {
-    task_create(0,test2);
-    task_create(1,test1);
-//    task_create(2,test3);
-    current_task=-1;
+    return current_task;
 }
 
 
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