further work on fork and friends

7 files changed, 106 insertions, 53 deletions

diff --git a/Makefile b/Makefile
index 0d76522..8ffd1ef 100644
--- a/Makefile
+++ b/Makefile
@@ -35,7 +35,7 @@ CFLAGS+=-ffreestanding
 CFLATS+=-Wall
 CFLAGS+=-Wextra
 #CFLAGS+=-O3
-#CFLAGS+=-O0
+CFLAGS+=-O0
 #CFLAGS+=-nostdlib 
 CFLAGS+=-std=gnu11
 CFLAGS+=-I.
diff --git a/asm/int_clock_handler.asm b/asm/int_clock_handler.asm
index 6301dc6..5e48658 100644
--- a/asm/int_clock_handler.asm
+++ b/asm/int_clock_handler.asm
@@ -9,7 +9,7 @@ cli
 pusha          ;Push all standard registers
 
 mov eax, esp	;save current stack pointer in esp
-mov esp, 0x1000	;now put the stack outside of virtual memory in kernel space!
+mov esp, 0x7000	;now put the stack outside of virtual memory in kernel space!
 
 push eax      ;Push pointer to all the stuff we just pushed
 call task_switch_next ;Call C code
diff --git a/asm/int_syscall_handler.asm b/asm/int_syscall_handler.asm
index 504d3e8..70090f0 100644
--- a/asm/int_syscall_handler.asm
+++ b/asm/int_syscall_handler.asm
@@ -1,6 +1,7 @@
 global int_syscall_handler
 [extern task_fork]
 [extern task_exit]
+[extern task_wait]
 
 
 [extern syscall_exit]
@@ -25,13 +26,15 @@ pid: dd 0x0
 
 int_syscall_handler:
 
-
 cmp eax, 72
 je call_fork
 
 cmp eax, 60
 je call_exit
 
+cmp eax, 77
+je call_wait
+
  cli
 
     push ebx
@@ -96,12 +99,35 @@ done_blocking:
 
     iret           ;Interrupt-Return
 
+call_wait:
+
+    cli
+
+    pusha          ;Push all standard registers
+
+    mov ebx, esp	;save current stack pointer in esp
+    mov esp, 0x7000	;now put the stack outside of virtual memory in kernel space!
+
+    push ebx      ;Push pointer to all the stuff we just pushed
+
+    call task_wait ;Call C code
+
+    mov esp, eax   ;Replace the stack with what the C code gave us
+
+    popa           ;Put the standard registers back
+
+    sti
+
+    iretd           ;Interrupt-Return
+    ;;;;
+
 call_exit:
 
     cli
 
     pusha          ;Push all standard registers
 
+    mov ebx, esp	;save current stack pointer in esp
     mov esp, 0x7000	;now put the stack outside of virtual memory in kernel space!
 
     push ebx      ;Push pointer to all the stuff we just pushed
@@ -126,7 +152,7 @@ call_fork:
     mov ebx, esp	;save current stack pointer in esp
     mov esp, 0x7000	;now put the stack outside of virtual memory in kernel space!
 
-    push ebx      ;Push pointer to all the stuff we just pushed
+    push ebx
     call task_fork ;Call C code
     mov [pid],eax
 
diff --git a/kernel/syscalls.c b/kernel/syscalls.c
index 41d77ec..44b04bd 100644
--- a/kernel/syscalls.c
+++ b/kernel/syscalls.c
@@ -120,15 +120,6 @@ int syscall_readdir(const char *name,fs_dirent *dirs,int max)
     return fs_readdir(name,dirs,max);
 }
 
-int syscall_wait(int *wait, int none1, int none2)
-{
-    #ifdef LOG_SYSCALLS
-    log(FOOLOS_MODULE_NAME,FOOLOS_LOG_INFO,"[%d] wait ",task_get_current_pid());
-    #endif
-
-    panic(FOOLOS_MODULE_NAME,"unhandled syscall");
-}
-
 int syscall_execve(char *name, char **argv1, char **env1)
 {
     char *argv[]={"/bin/foolshell",NULL};
@@ -221,17 +212,6 @@ uint32_t syscall_sbrk(int incr, int none1, int none2)
 }
 
 
-int syscall_exit(int ret, char **env, int none2)
-{
-    #ifdef LOG_SYSCALLS
-    log(FOOLOS_MODULE_NAME,FOOLOS_LOG_INFO,"exit (ret=%d) (env=0x%08X)", ret, env);
-    #endif
-
-    panic(FOOLOS_MODULE_NAME,"exit not supported yet" );
-
-}
-
-
 // stat, fstat, lstat
 int syscall_stat(const char *path, struct stat *st,int none)
 {
diff --git a/kernel/task.c b/kernel/task.c
index 6ea9b79..ac54dbe 100644
--- a/kernel/task.c
+++ b/kernel/task.c
@@ -17,7 +17,7 @@
 
 #define MAX_TASKS 10
 
-static volatile int current_task=-2;
+static volatile int current_task=-1;
 
 static volatile struct task_list_struct
 {
@@ -25,6 +25,8 @@ static volatile struct task_list_struct
     bool active;
     uint32_t esp; // stack pointer of the task;
     uint32_t vmem; // number of virtual memory table to switch to
+    bool waiting;
+    bool skipwait;
     
 }volatile task_list[MAX_TASKS];
 
@@ -40,6 +42,8 @@ int add_task(uint32_t esp, uint32_t vmem)
 	    task_list[i].vmem=vmem;
 	    task_list[i].esp=esp;
 	    task_list[i].active=true;
+	    task_list[i].waiting=false;
+	    task_list[i].skipwait=false;
 
 	    return i;
 	}
@@ -48,22 +52,19 @@ int add_task(uint32_t esp, uint32_t vmem)
     panic(FOOLOS_MODULE_NAME,"out of task slots!");
 }
 
-// this gets called by our clock interrupt regularly!
-uint32_t task_switch_next(uint32_t oldesp)
+uint32_t my_scheduler(uint32_t oldesp)
 {
-    timer_tick();
-
-    if(current_task==-2)return oldesp;
-    
     task_list[current_task].esp=oldesp;
-    
+
     for(int i=0;i<MAX_TASKS;i++)
     {
 	int pid=(current_task+1+i)%MAX_TASKS; // schedule round robin style
 
-	if(task_list[pid].active)
+	if(task_list[pid].active && !task_list[pid].waiting)
 	{
-	  //  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);
+	  //  if(current_task!=pid)
+	//	    log(FOOLOS_MODULE_NAME,FOOLOS_LOG_INFO,"switch from %d to %d", current_task, pid);
+
 	    current_task=pid;
 
 	    vmem_set_dir(task_list[pid].vmem);
@@ -72,34 +73,68 @@ uint32_t task_switch_next(uint32_t oldesp)
 
     }
 
-    return oldesp;
+    panic(FOOLOS_MODULE_NAME,"nothing to schedule!");
+}
+
+// this gets called by our clock interrupt regularly!
+uint32_t task_switch_next(uint32_t oldesp)
+{
+    timer_tick();
+
+    // check if multitasking has been started
+    if(current_task<0)return oldesp; 
+
+    return my_scheduler(oldesp);
 
 }
 
+
 //TODO: free vmem too!
+//TODO: notify waiting parent when child finished;
 uint32_t task_exit(uint32_t oldesp)
 { 
     task_list[current_task].active=false;
+    int parent_pid=task_list[current_task].parent;
 
-    for(int i=0;i<MAX_TASKS;i++)
+    log(FOOLOS_MODULE_NAME,FOOLOS_LOG_INFO,"[%d] exit ", current_task);
+    if(task_list[parent_pid].active)
     {
-	int pid=(current_task+1+i)%MAX_TASKS; // schedule round robin style
-
-	if(task_list[pid].active)
+	if(task_list[parent_pid].waiting)
 	{
-	  //  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;
-
-	    vmem_set_dir(task_list[pid].vmem);
-	    return task_list[pid].esp;
+    
+	   log(FOOLOS_MODULE_NAME,FOOLOS_LOG_INFO,"wakeing up %d ", parent_pid);
+	   task_list[parent_pid].waiting=false;
+	}
+	else
+	{
+	   log(FOOLOS_MODULE_NAME,FOOLOS_LOG_INFO,"set skipwait on %d ", parent_pid);
+	   task_list[parent_pid].skipwait=true;
 	}
+	
+    }
+
+    return my_scheduler(oldesp);
+
+}
 
+uint32_t task_wait(uint32_t oldesp)
+{ 
+    log(FOOLOS_MODULE_NAME,FOOLOS_LOG_INFO,"[%d] wait", current_task);
+    if(task_list[current_task].skipwait)
+    {
+	task_list[current_task].skipwait=false;
+    }
+    else
+    {
+	task_list[current_task].waiting=true;
     }
+    return my_scheduler(oldesp);
 }
 
 uint32_t task_fork(uint32_t oldesp)
 { 
    int pid=add_task(oldesp,vmem_new_space_dir(task_list[current_task].vmem));
+   log(FOOLOS_MODULE_NAME,FOOLOS_LOG_INFO,"[%d] forked -> [%d]", current_task, pid);
    return pid;
 }
 
@@ -107,7 +142,9 @@ uint32_t task_fork(uint32_t oldesp)
 void task_init()
 {
     // this is our main task on slot 0 
+    task_list[0].parent=0;
     task_list[0].active=true;
+    task_list[0].waiting=false;
     task_list[0].vmem=0;
     task_list[0].esp = 0; // will be set by next task_switch_next() call.
     current_task=0;
diff --git a/userspace/foolshell.c b/userspace/foolshell.c
index 78ba327..7d2291e 100644
--- a/userspace/foolshell.c
+++ b/userspace/foolshell.c
@@ -109,7 +109,7 @@ int process(char *buf)
 
     if(!strcmp(command,"help"))
     {
-	puts("foolshell: supported built-in commands: 'help', 'echo [string]', 'malloc [bytes]', 'free [address]', 'getenv [var]', 'putenv/setenv [var] [val]', 'env' 'cd [dir]'");
+	puts("foolshell: supported built-in commands: 'help', 'echo [string]', 'malloc [bytes]', 'free [address]', 'getenv [var]', 'putenv/setenv [var] [val]', 'env' 'cd [dir]', 'exit'");
     }
     else if(!strcmp(command,"cd"))
     {
@@ -173,6 +173,11 @@ int process(char *buf)
 	setenv("PWD",buf,1);
 
     }
+    else if(!strcmp(command,"exit"))
+    {
+	exit(1);
+
+    }
     else if(!strcmp(command,"echo"))
     {
 	printf("\"%s\"\n",token[1]);
@@ -215,12 +220,18 @@ int process(char *buf)
 	if(pid!=0)
 	{
 	    printf("new task pid: %i \n",pid);
+	}
+	if(pid==0)
+	{
 	    char buf[256];
 	    sprintf(buf,"%s/%s",getenv("PATH"),token[0]);
+	    sprintf(buf,"%s/%s","/bin",token[0]);
 	    execve(buf,token,environ);
 	    puts("foolshell: command not found");
 	    exit(1);
 	}
+	int status;
+	wait(&status);
 
     }
     return 0;
diff --git a/userspace/init.c b/userspace/init.c
index fd562a9..8c3bcd7 100644
--- a/userspace/init.c
+++ b/userspace/init.c
@@ -1,21 +1,20 @@
+
 int main(int argc, char **argv)
 {
     int pid=fork();
 
-    if(pid!=0)
+    if(pid==0)
     {
-	printf("fool-init: forked child (pid: %i) spawning a Fools Shell\n",pid);
 	execve("/bin/foolshell",0,0);
-
     }
     else
     {
-	// TODO: wait for child and respawn shell if needed!
-	volatile int i=0;
-	while(1)
-	{
+	printf("fool-init: forked child (pid: %i) spawning a Fools Shell\n",pid);
+	int status;
+	int pid_ret=wait(&status);
+	puts("child state has changed!");
+	execve("/bin/init",0,0);
 
-	}
     }
     return 0;
 }