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task.h File Reference

Headers for the task manager. More...

#include <arch/paging.h>
#include <arch/i386.h>

Go to the source code of this file.

Data Structures
struct	task
	The task structure. More...
struct	tss
	TSS without I/O bit map. More...
struct	tss_IO
	TSS with I/O bit map. More...
Defines
#define	STACK_SIZE   0x8000
	Stack size in byte for every kernel-mode task.
#define	TASK_STACK_START   0xC0000000
	The address where the user-privilege task stack is placed.
#define	TASK_HEAP_START   0x40000000
	The start of the heap for a user-mode task.
#define	TASK_HEAP_DEFAULT_SIZE   0x40000000
	The size of the heap for a user-mode task.
#define	READY   1
	The task is ready for the CPU.
#define	WAIT   2
	The task is waiting for I/O.
#define	ZOMBIE   3
	The task is dying.
#define	KTHREAD_T   0x00
	A kernel thread type.
#define	PROCESS_T   0x01
	A task type.
#define	KERNEL_PRIVILEGE   0
	Max privilege (kernel).
#define	USER_PRIVILEGE   3
	Min privilege (user).
#define	MYSELF   ( get_curr_task() )
	Macro equivalent to get_curr_task() routine.
#define	_exit(n)   auto_kill(n)
	Macro equivalent to auto_kill() (...for now).
Typedefs
typedef tss	tss_t
	TSS without I/O bit map.
typedef tss_IO	tss_IO_t
	TSS with I/O bit map.
typedef task	task_t
	The task structure.
Functions
__inline__ void	idle ()
	Halt the CPU until an interrupt occurs.
__inline__ void	jmp_to_tss (word tss_sel)
	Perform a context switch between two tasks. Parameters: tss_sel  The selector of the next task.
void	dispatcher ()
	The dispatcher.
void	init_multitasking ()
	Initialize the multitasking management.
int	get_pid ()
	Return the current task pid if there is a curr_task. Returns: The current task pid.
char *	get_pname ()
	Return the current task name if there is a curr_task. Returns: The current task name.
task_t *	get_curr_task ()
	Get the current task. Returns: The current task structure pointer.
void	do_idle ()
	Simply do nothing...
task_t *	create_kthread (void *address, char *pname)
	Create a new kernel thread. Parameters: address  The address of the starting point for the thread. pname  The name of the new thread. Returns: A pointer to the new-created task structure. Exceptions: NULL  If an error occurs (in particular out-of-memory).
task_t *	create_process (void *address, void *buffer, size_t size, char *pname, int privilege)
	Create a new process. Parameters: address  The address of the starting point for the thread. buffer  An address to a buffer where is placed the executable code. size  The size of the executable code buffer. pname  The name of the new task. privilege  The privilege level of the new task: KERNEL_PRIVILEGE USER_PRIVILEGE Returns: A pointer to the new-created task structure. Exceptions: NULL  If an error occurs (in particular out-of-memory).
task_t *	new_task (char *filename, int argc, char **argv, int privilege)
	Execute a file creating a new task. Parameters: filename  The name of the file to execute. argc  The number of arguments passed to the new process. argv  The arguments passed to the new process. argv  A pointer to the argument strings. privilege  The privilege level of the new task: KERNEL_PRIVILEGE USER_PRIVILEGE Returns: A pointer to the new-created task structure. Exceptions: NULL  If an error occurs (in particular out-of-memory).
void	auto_kill (int n)
	Kill the current running task. Parameters: n  The return code.
bool	kill (pid_t pid)
	Kill a task by the pid. Parameters: pid  The process id. Returns: TRUE if the task has been successfully killed FALSE if the task cannot be killed.
pid_t	waitpid (pid_t pid, int *status, int options)
	Wait for the exit of a child. Parameters: pid  The child process id -1 to wait for the exit of a generic child. status  Reports the status of the child. options  Options flags. Returns: The pid of the child or -1 if the process has not been found.
void	sleep_task (task_t *p)
	Sleep a process if it is awake. Parameters: p  The structure of the task to sleep.
void	wakeup_task (task_t *p)
	Wakeup a process if it is sleeping. Parameters: p  The structure of the task to wakeup.
void	sched_enter_critical_region ()
	Disable the scheduling of the other tasks. Warning: ATTENTION!!! Remember to call sched_leave_critical_region() when the task exits from the critical region. Otherwise the whole system could be blocked, because the scheduling of the other tasks is disabled after a task calls this function.
void	sched_leave_critical_region ()
	Re-enable scheduling for the other tasks.
bool	is_sched_enabled ()
	Return if the scheduling is enabled or not. Returns: TRUE if the scheduling is enabled FALSE otherwise.
void	ps ()
	Print the state of every process from the ready, wait and zombie queues.

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Detailed Description

Headers for the task manager.

Author:

Andrea Righi <drizzt@inwind.it>

Date:

Last update: 2003-12-16

Note:

Copyright (©) 2003 Andrea Righi

Definition in file task.h.

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Define Documentation

#define _exit (  n    )     auto_kill(n)

Macro equivalent to auto_kill() (...for now). Todo: The exit returning values between tasks. Definition at line 157 of file task.h.

#define KERNEL_PRIVILEGE   0

Max privilege (kernel). Definition at line 31 of file task.h.

#define KTHREAD_T   0x00

A kernel thread type. Definition at line 28 of file task.h.

#define MYSELF   ( get_curr_task() )

Macro equivalent to get_curr_task() routine. Definition at line 142 of file task.h.

#define PROCESS_T   0x01

A task type. Definition at line 29 of file task.h.

#define READY   1

The task is ready for the CPU. Definition at line 24 of file task.h.

#define STACK_SIZE   0x8000

Stack size in byte for every kernel-mode task. Definition at line 15 of file task.h.

#define TASK_HEAP_DEFAULT_SIZE   0x40000000

The size of the heap for a user-mode task. Definition at line 22 of file task.h.

#define TASK_HEAP_START   0x40000000

The start of the heap for a user-mode task. Definition at line 20 of file task.h.

#define TASK_STACK_START   0xC0000000

The address where the user-privilege task stack is placed. Definition at line 18 of file task.h.

#define USER_PRIVILEGE   3

Min privilege (user). Definition at line 32 of file task.h.

#define WAIT   2

The task is waiting for I/O. Definition at line 25 of file task.h.

#define ZOMBIE   3

The task is dying. Definition at line 26 of file task.h.

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Typedef Documentation

typedef struct task task_t

The task structure.

typedef struct tss_IO tss_IO_t

TSS with I/O bit map.

typedef struct tss tss_t

TSS without I/O bit map.

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Function Documentation

__inline__ void idle (    )  [static]

Halt the CPU until an interrupt occurs. Definition at line 109 of file task.h. { __asm__ __volatile__ ("hlt"); }

__inline__ void jmp_to_tss (  word    tss_sel )  [static]

Perform a context switch between two tasks. Parameters: tss_sel  The selector of the next task. This is an asm routine to jump to a TSS (TSS-based multitasking) Definition at line 121 of file task.h. { static struct { unsigned eip : 32; // 32 bit unsigned cs : 16; // 16 bit } __attribute__ ((packed)) tss_link = {0, 0}; // Set the TSS link // tss_link.cs = tss_sel; // Jump to the task // __asm__ __volatile__ ("ljmp *(%0)" : : "m" (tss_link)); }

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