sched.h

unix/linux 编程实践一书的所有源代码

extern struct task_struct *task[NR_TASKS];

extern struct task_struct **tarray_freelist;
extern spinlock_t taskslot_lock;

extern __inline__ void add_free_taskslot(struct task_struct **t)
{
	spin_lock(&taskslot_lock);
	*t = (struct task_struct *) tarray_freelist;
	tarray_freelist = t;
	spin_unlock(&taskslot_lock);
}

extern __inline__ struct task_struct **get_free_taskslot(void)
{
	struct task_struct **tslot;

	spin_lock(&taskslot_lock);
	if((tslot = tarray_freelist) != NULL)
		tarray_freelist = (struct task_struct **) *tslot;
	spin_unlock(&taskslot_lock);

	return tslot;
}

/* PID hashing. */
#define PIDHASH_SZ (NR_TASKS >> 2)
extern struct task_struct *pidhash[PIDHASH_SZ];

#define pid_hashfn(x)	((((x) >> 8) ^ (x)) & (PIDHASH_SZ - 1))

extern __inline__ void hash_pid(struct task_struct *p)
{
	struct task_struct **htable = &pidhash[pid_hashfn(p->pid)];

	if((p->pidhash_next = *htable) != NULL)
		(*htable)->pidhash_pprev = &p->pidhash_next;
	*htable = p;
	p->pidhash_pprev = htable;
}

extern __inline__ void unhash_pid(struct task_struct *p)
{
	if(p->pidhash_next)
		p->pidhash_next->pidhash_pprev = p->pidhash_pprev;
	*p->pidhash_pprev = p->pidhash_next;
}

extern __inline__ struct task_struct *find_task_by_pid(int pid)
{
	struct task_struct *p, **htable = &pidhash[pid_hashfn(pid)];

	for(p = *htable; p && p->pid != pid; p = p->pidhash_next)
		;

	return p;
}

/* per-UID process charging. */
extern int alloc_uid(struct task_struct *p);
void free_uid(struct task_struct *p);

#include <asm/current.h>

extern unsigned long volatile jiffies;
extern unsigned long itimer_ticks;
extern unsigned long itimer_next;
extern struct timeval xtime;
extern void do_timer(struct pt_regs *);

extern unsigned int * prof_buffer;
extern unsigned long prof_len;
extern unsigned long prof_shift;

#define CURRENT_TIME (xtime.tv_sec)

extern void FASTCALL(__wake_up(struct wait_queue ** p, unsigned int mode));
extern void FASTCALL(sleep_on(struct wait_queue ** p));
extern long FASTCALL(sleep_on_timeout(struct wait_queue ** p,
				      signed long timeout));
extern void FASTCALL(interruptible_sleep_on(struct wait_queue ** p));
extern long FASTCALL(interruptible_sleep_on_timeout(struct wait_queue ** p,
						    signed long timeout));
extern void FASTCALL(wake_up_process(struct task_struct * tsk));

#define wake_up(x)			__wake_up((x),TASK_UNINTERRUPTIBLE | TASK_INTERRUPTIBLE)
#define wake_up_interruptible(x)	__wake_up((x),TASK_INTERRUPTIBLE)

extern int in_group_p(gid_t grp);

extern void flush_signals(struct task_struct *);
extern void flush_signal_handlers(struct task_struct *);
extern int dequeue_signal(sigset_t *block, siginfo_t *);
extern int send_sig_info(int, struct siginfo *info, struct task_struct *);
extern int force_sig_info(int, struct siginfo *info, struct task_struct *);
extern int kill_pg_info(int, struct siginfo *info, pid_t);
extern int kill_sl_info(int, struct siginfo *info, pid_t);
extern int kill_proc_info(int, struct siginfo *info, pid_t);
extern int kill_something_info(int, struct siginfo *info, int);
extern void notify_parent(struct task_struct * tsk, int);
extern void force_sig(int sig, struct task_struct * p);
extern int send_sig(int sig, struct task_struct * p, int priv);
extern int kill_pg(pid_t, int, int);
extern int kill_sl(pid_t, int, int);
extern int kill_proc(pid_t, int, int);
extern int do_sigaction(int sig, const struct k_sigaction *act,
			struct k_sigaction *oact);
extern int do_sigaltstack(const stack_t *ss, stack_t *oss, unsigned long sp);

extern inline int signal_pending(struct task_struct *p)
{
	return (p->sigpending != 0);
}

/* Reevaluate whether the task has signals pending delivery.
   This is required every time the blocked sigset_t changes.
   All callers should have t->sigmask_lock.  */

static inline void recalc_sigpending(struct task_struct *t)
{
	unsigned long ready;
	long i;

	switch (_NSIG_WORDS) {
	default:
		for (i = _NSIG_WORDS, ready = 0; --i >= 0 ;)
			ready |= t->signal.sig[i] &~ t->blocked.sig[i];
		break;

	case 4: ready  = t->signal.sig[3] &~ t->blocked.sig[3];
		ready |= t->signal.sig[2] &~ t->blocked.sig[2];
		ready |= t->signal.sig[1] &~ t->blocked.sig[1];
		ready |= t->signal.sig[0] &~ t->blocked.sig[0];
		break;

	case 2: ready  = t->signal.sig[1] &~ t->blocked.sig[1];
		ready |= t->signal.sig[0] &~ t->blocked.sig[0];
		break;

	case 1: ready  = t->signal.sig[0] &~ t->blocked.sig[0];
	}

	t->sigpending = (ready != 0);
}

/* True if we are on the alternate signal stack.  */

static inline int on_sig_stack(unsigned long sp)
{
	return (sp >= current->sas_ss_sp
		&& sp < current->sas_ss_sp + current->sas_ss_size);
}

static inline int sas_ss_flags(unsigned long sp)
{
	return (current->sas_ss_size == 0 ? SS_DISABLE
		: on_sig_stack(sp) ? SS_ONSTACK : 0);
}

extern int request_irq(unsigned int irq,
		       void (*handler)(int, void *, struct pt_regs *),
		       unsigned long flags, 
		       const char *device,
		       void *dev_id);
extern void free_irq(unsigned int irq, void *dev_id);

/*
 * This has now become a routine instead of a macro, it sets a flag if
 * it returns true (to do BSD-style accounting where the process is flagged
 * if it uses root privs). The implication of this is that you should do
 * normal permissions checks first, and check suser() last.
 *
 * [Dec 1997 -- Chris Evans]
 * For correctness, the above considerations need to be extended to
 * fsuser(). This is done, along with moving fsuser() checks to be
 * last.
 *
 * These will be removed, but in the mean time, when the SECURE_NOROOT 
 * flag is set, uids don't grant privilege.
 */
extern inline int suser(void)
{
	if (!issecure(SECURE_NOROOT) && current->euid == 0) { 
		current->flags |= PF_SUPERPRIV;
		return 1;
	}
	return 0;
}

extern inline int fsuser(void)
{
	if (!issecure(SECURE_NOROOT) && current->fsuid == 0) {
		current->flags |= PF_SUPERPRIV;
		return 1;
	}
	return 0;
}

/*
 * capable() checks for a particular capability.  
 * New privilege checks should use this interface, rather than suser() or
 * fsuser(). See include/linux/capability.h for defined capabilities.
 */

extern inline int capable(int cap)
{
#if 1 /* ok now */
	if (cap_raised(current->cap_effective, cap))
#else
	if (cap_is_fs_cap(cap) ? current->fsuid == 0 : current->euid == 0)
#endif
        {
		current->flags |= PF_SUPERPRIV;
		return 1;
	}
	return 0;
}

/*
 * Routines for handling mm_structs
 */
extern struct mm_struct * mm_alloc(void);
static inline void mmget(struct mm_struct * mm)
{
	atomic_inc(&mm->count);
}
extern void mmput(struct mm_struct *);
/* Remove the current tasks stale references to the old mm_struct */
extern void mm_release(void);

/*
 * Routines for handling the fd arrays
 */
extern struct file ** alloc_fd_array(int);
extern int expand_fd_array(struct files_struct *, int nr);
extern void free_fd_array(struct file **, int);

extern fd_set *alloc_fdset(int);
extern int expand_fdset(struct files_struct *, int nr);
extern void free_fdset(fd_set *, int);

/* Expand files.  Return <0 on error; 0 nothing done; 1 files expanded,
 * we may have blocked. */
static inline int expand_files(struct files_struct *files, int nr)
{
	int err, expand = 0;
#ifdef FDSET_DEBUG	
	printk (KERN_ERR __FUNCTION__ " %d: nr = %d\n", current->pid, nr);
#endif
	
	if (nr >= files->max_fdset) {
		expand = 1;
		if ((err = expand_fdset(files, nr + 1)))
			goto out;
	}
	if (nr >= files->max_fds) {
		expand = 1;
		if ((err = expand_fd_array(files, nr + 1)))
			goto out;
	}
	err = expand;
 out:
#ifdef FDSET_DEBUG	
	if (err)
		printk (KERN_ERR __FUNCTION__ " %d: return %d\n", current->pid, err);
#endif
	return err;
}

extern int  copy_thread(int, unsigned long, unsigned long, struct task_struct *, struct pt_regs *);
extern void flush_thread(void);
extern void exit_thread(void);

extern void exit_mm(struct task_struct *);
extern void exit_fs(struct task_struct *);
extern void exit_files(struct task_struct *);
extern void exit_sighand(struct task_struct *);

extern int do_execve(char *, char **, char **, struct pt_regs *);
extern int do_fork(unsigned long, unsigned long, struct pt_regs *);

/*
 * The wait-queues are circular lists, and you have to be *very* sure
 * to keep them correct. Use only these two functions to add/remove
 * entries in the queues.
 */
extern inline void __add_wait_queue(struct wait_queue ** p, struct wait_queue * wait)
{
	wait->next = *p ? : WAIT_QUEUE_HEAD(p);
	*p = wait;
}

extern rwlock_t waitqueue_lock;

extern inline void add_wait_queue(struct wait_queue ** p, struct wait_queue * wait)
{
	unsigned long flags;

	write_lock_irqsave(&waitqueue_lock, flags);
	__add_wait_queue(p, wait);
	write_unlock_irqrestore(&waitqueue_lock, flags);
}

extern inline void __remove_wait_queue(struct wait_queue ** p, struct wait_queue * wait)
{
	struct wait_queue * next = wait->next;
	struct wait_queue * head = next;
	struct wait_queue * tmp;

	while ((tmp = head->next) != wait) {
		head = tmp;
	}
	head->next = next;
}

extern inline void remove_wait_queue(struct wait_queue ** p, struct wait_queue * wait)
{
	unsigned long flags;

	write_lock_irqsave(&waitqueue_lock, flags);
	__remove_wait_queue(p, wait);
	write_unlock_irqrestore(&waitqueue_lock, flags); 
}

#define __wait_event(wq, condition) 					\
do {									\
	struct wait_queue __wait;					\
									\
	__wait.task = current;						\
	add_wait_queue(&wq, &__wait);					\
	for (;;) {							\
		current->state = TASK_UNINTERRUPTIBLE;			\
		mb();							\
		if (condition)						\
			break;						\
		schedule();						\
	}								\
	current->state = TASK_RUNNING;					\
	remove_wait_queue(&wq, &__wait);				\
} while (0)

#define wait_event(wq, condition) 					\
do {									\
	if (condition)	 						\
		break;							\
	__wait_event(wq, condition);					\
} while (0)

#define __wait_event_interruptible(wq, condition, ret)			\
do {									\
	struct wait_queue __wait;					\
									\
	__wait.task = current;						\
	add_wait_queue(&wq, &__wait);					\
	for (;;) {							\
		current->state = TASK_INTERRUPTIBLE;			\
		mb();							\
		if (condition)						\
			break;						\
		if (!signal_pending(current)) {				\
			schedule();					\
			continue;					\
		}							\
		ret = -ERESTARTSYS;					\
		break;							\
	}								\
	current->state = TASK_RUNNING;					\
	remove_wait_queue(&wq, &__wait);				\
} while (0)
	
#define wait_event_interruptible(wq, condition)				\
({									\
	int __ret = 0;							\
	if (!(condition))						\
		__wait_event_interruptible(wq, condition, __ret);	\
	__ret;								\
})

#define REMOVE_LINKS(p) do { \
	(p)->next_task->prev_task = (p)->prev_task; \
	(p)->prev_task->next_task = (p)->next_task; \
	if ((p)->p_osptr) \
		(p)->p_osptr->p_ysptr = (p)->p_ysptr; \
	if ((p)->p_ysptr) \
		(p)->p_ysptr->p_osptr = (p)->p_osptr; \
	else \
		(p)->p_pptr->p_cptr = (p)->p_osptr; \
	} while (0)

#define SET_LINKS(p) do { \
	(p)->next_task = &init_task; \
	(p)->prev_task = init_task.prev_task; \
	init_task.prev_task->next_task = (p); \
	init_task.prev_task = (p); \
	(p)->p_ysptr = NULL; \
	if (((p)->p_osptr = (p)->p_pptr->p_cptr) != NULL) \
		(p)->p_osptr->p_ysptr = p; \
	(p)->p_pptr->p_cptr = p; \
	} while (0)

#define for_each_task(p) \
	for (p = &init_task ; (p = p->next_task) != &init_task ; )

#endif /* __KERNEL__ */

#endif