sched.h

中科院徐志伟老师一书《操作系统 原理·技术与编程》的源代码和习题接

    sigpending:		0,						\
    addr_limit:		KERNEL_DS,					\
    exec_domain:	&default_exec_domain,				\
    lock_depth:		-1,						\
    counter:		DEF_COUNTER,					\
    nice:		DEF_NICE,					\
    policy:		SCHED_OTHER,					\
    mm:			NULL,						\
    active_mm:		&init_mm,					\
    cpus_runnable:	-1,						\
    cpus_allowed:	-1,						\
    run_list:		LIST_HEAD_INIT(tsk.run_list),			\
    next_task:		&tsk,						\
    prev_task:		&tsk,						\
    p_opptr:		&tsk,						\
    p_pptr:		&tsk,						\
    thread_group:	LIST_HEAD_INIT(tsk.thread_group),		\
    wait_chldexit:	__WAIT_QUEUE_HEAD_INITIALIZER(tsk.wait_chldexit),\
    real_timer:		{						\
	function:		it_real_fn				\
    },									\
    cap_effective:	CAP_INIT_EFF_SET,				\
    cap_inheritable:	CAP_INIT_INH_SET,				\
    cap_permitted:	CAP_FULL_SET,					\
    keep_capabilities:	0,						\
    rlim:		INIT_RLIMITS,					\
    user:		INIT_USER,					\
    comm:		"swapper",					\
    thread:		INIT_THREAD,					\
    fs:			&init_fs,					\
    files:		&init_files,					\
    sigmask_lock:	SPIN_LOCK_UNLOCKED,				\
    sig:		&init_signals,					\
    pending:		{ NULL, &tsk.pending.head, {{0}}},		\
    blocked:		{{0}},						\
    alloc_lock:		SPIN_LOCK_UNLOCKED,				\
    journal_info:	NULL,						\
}


#ifndef INIT_TASK_SIZE
# define INIT_TASK_SIZE	2048*sizeof(long)
#endif

union task_union {
	struct task_struct task;
	unsigned long stack[INIT_TASK_SIZE/sizeof(long)];
};

extern union task_union init_task_union;

extern struct   mm_struct init_mm;
extern struct task_struct *init_tasks[NR_CPUS];

/* PID hashing. (shouldnt this be dynamic?) */
#define PIDHASH_SZ (4096 >> 2)
extern struct task_struct *pidhash[PIDHASH_SZ];

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

static 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;
}

static 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;
}

static 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;
}

#define task_has_cpu(tsk) ((tsk)->cpus_runnable != ~0UL)

static inline void task_set_cpu(struct task_struct *tsk, unsigned int cpu)
{
	tsk->processor = cpu;
	tsk->cpus_runnable = 1UL << cpu;
}

static inline void task_release_cpu(struct task_struct *tsk)
{
	tsk->cpus_runnable = ~0UL;
}

/* per-UID process charging. */
extern struct user_struct * alloc_uid(uid_t);
extern void free_uid(struct user_struct *);

#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(wait_queue_head_t *q, unsigned int mode, int nr));
extern void FASTCALL(__wake_up_sync(wait_queue_head_t *q, unsigned int mode, int nr));
extern void FASTCALL(sleep_on(wait_queue_head_t *q));
extern long FASTCALL(sleep_on_timeout(wait_queue_head_t *q,
				      signed long timeout));
extern void FASTCALL(interruptible_sleep_on(wait_queue_head_t *q));
extern long FASTCALL(interruptible_sleep_on_timeout(wait_queue_head_t *q,
						    signed long timeout));
extern int FASTCALL(wake_up_process(struct task_struct * tsk));

#define wake_up(x)			__wake_up((x),TASK_UNINTERRUPTIBLE | TASK_INTERRUPTIBLE, 1)
#define wake_up_nr(x, nr)		__wake_up((x),TASK_UNINTERRUPTIBLE | TASK_INTERRUPTIBLE, nr)
#define wake_up_all(x)			__wake_up((x),TASK_UNINTERRUPTIBLE | TASK_INTERRUPTIBLE, 0)
#define wake_up_sync(x)			__wake_up_sync((x),TASK_UNINTERRUPTIBLE | TASK_INTERRUPTIBLE, 1)
#define wake_up_sync_nr(x, nr)		__wake_up_sync((x),TASK_UNINTERRUPTIBLE | TASK_INTERRUPTIBLE, nr)
#define wake_up_interruptible(x)	__wake_up((x),TASK_INTERRUPTIBLE, 1)
#define wake_up_interruptible_nr(x, nr)	__wake_up((x),TASK_INTERRUPTIBLE, nr)
#define wake_up_interruptible_all(x)	__wake_up((x),TASK_INTERRUPTIBLE, 0)
#define wake_up_interruptible_sync(x)	__wake_up_sync((x),TASK_INTERRUPTIBLE, 1)
#define wake_up_interruptible_sync_nr(x) __wake_up_sync((x),TASK_INTERRUPTIBLE,  nr)
asmlinkage long sys_wait4(pid_t pid,unsigned int * stat_addr, int options, struct rusage * ru);

extern int in_group_p(gid_t);
extern int in_egroup_p(gid_t);

extern void proc_caches_init(void);
extern void flush_signals(struct task_struct *);
extern void flush_signal_handlers(struct task_struct *);
extern int dequeue_signal(sigset_t *, siginfo_t *);
extern void block_all_signals(int (*notifier)(void *priv), void *priv,
			      sigset_t *mask);
extern void unblock_all_signals(void);
extern int send_sig_info(int, struct siginfo *, struct task_struct *);
extern int force_sig_info(int, struct siginfo *, struct task_struct *);
extern int kill_pg_info(int, struct siginfo *, pid_t);
extern int kill_sl_info(int, struct siginfo *, pid_t);
extern int kill_proc_info(int, struct siginfo *, pid_t);
extern void notify_parent(struct task_struct *, int);
extern void do_notify_parent(struct task_struct *, int);
extern void force_sig(int, struct task_struct *);
extern int send_sig(int, struct task_struct *, int);
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, const struct k_sigaction *, struct k_sigaction *);
extern int do_sigaltstack(const stack_t *, stack_t *, unsigned long);

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

/*
 * Re-calculate pending state from the set of locally pending
 * signals, globally pending signals, and blocked signals.
 */
static inline int has_pending_signals(sigset_t *signal, sigset_t *blocked)
{
	unsigned long ready;
	long i;

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

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

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

	case 1: ready  = signal->sig[0] &~ blocked->sig[0];
	}
	return ready !=	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)
{
	t->sigpending = has_pending_signals(&t->pending.signal, &t->blocked);
}

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

static inline int on_sig_stack(unsigned long sp)
{
	return (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,
		       void (*handler)(int, void *, struct pt_regs *),
		       unsigned long, const char *, void *);
extern void free_irq(unsigned int, void *);

/*
 * 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.
 */
static inline int suser(void)
{
	if (!issecure(SECURE_NOROOT) && current->euid == 0) { 
		current->flags |= PF_SUPERPRIV;
		return 1;
	}
	return 0;
}

static 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.
 */

static 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);

extern struct mm_struct * start_lazy_tlb(void);
extern void end_lazy_tlb(struct mm_struct *mm);

/* mmdrop drops the mm and the page tables */
extern inline void FASTCALL(__mmdrop(struct mm_struct *));
static inline void mmdrop(struct mm_struct * mm)
{
	if (atomic_dec_and_test(&mm->mm_count))
		__mmdrop(mm);
}

/* mmput gets rid of the mappings and all user-space */
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);

extern int  copy_thread(int, unsigned long, 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_files(struct task_struct *);
extern void exit_sighand(struct task_struct *);

extern void reparent_to_init(void);
extern void daemonize(void);

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

extern void FASTCALL(add_wait_queue(wait_queue_head_t *q, wait_queue_t * wait));
extern void FASTCALL(add_wait_queue_exclusive(wait_queue_head_t *q, wait_queue_t * wait));
extern void FASTCALL(remove_wait_queue(wait_queue_head_t *q, wait_queue_t * wait));

#define __wait_event(wq, condition) 					\
do {									\
	wait_queue_t __wait;						\
	init_waitqueue_entry(&__wait, current);				\
									\
	add_wait_queue(&wq, &__wait);					\
	for (;;) {							\
		set_current_state(TASK_UNINTERRUPTIBLE);		\
		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 {									\
	wait_queue_t __wait;						\
	init_waitqueue_entry(&__wait, current);				\
									\
	add_wait_queue(&wq, &__wait);					\
	for (;;) {							\
		set_current_state(TASK_INTERRUPTIBLE);			\
		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 ; )

#define next_thread(p) \
	list_entry((p)->thread_group.next, struct task_struct, thread_group)

static inline void del_from_runqueue(struct task_struct * p)
{
	nr_running--;
	p->sleep_time = jiffies;
	list_del(&p->run_list);
	p->run_list.next = NULL;
}

static inline int task_on_runqueue(struct task_struct *p)
{
	return (p->run_list.next != NULL);
}

static inline void unhash_process(struct task_struct *p)
{
	if (task_on_runqueue(p)) BUG();
	write_lock_irq(&tasklist_lock);
	nr_threads--;
	unhash_pid(p);
	REMOVE_LINKS(p);
	list_del(&p->thread_group);
	write_unlock_irq(&tasklist_lock);
}

/* Protects ->fs, ->files, ->mm, and synchronises with wait4().  Nests inside tasklist_lock */
static inline void task_lock(struct task_struct *p)
{
	spin_lock(&p->alloc_lock);
}

static inline void task_unlock(struct task_struct *p)
{
	spin_unlock(&p->alloc_lock);
}

/* write full pathname into buffer and return start of pathname */
static inline char * d_path(struct dentry *dentry, struct vfsmount *vfsmnt,
				char *buf, int buflen)
{
	char *res;
	struct vfsmount *rootmnt;
	struct dentry *root;
	read_lock(&current->fs->lock);
	rootmnt = mntget(current->fs->rootmnt);
	root = dget(current->fs->root);
	read_unlock(&current->fs->lock);
	spin_lock(&dcache_lock);
	res = __d_path(dentry, vfsmnt, root, rootmnt, buf, buflen);
	spin_unlock(&dcache_lock);
	dput(root);
	mntput(rootmnt);
	return res;
}

#endif /* __KERNEL__ */

#endif