sched.h

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#ifndef _LINUX_SCHED_H
#define _LINUX_SCHED_H

#include <asm/param.h>  /* for HZ */

extern unsigned long global_event;

#include <linux/binfmts.h>
#include <linux/personality.h>
#include <linux/tasks.h>
#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/times.h>
#include <linux/timex.h>

#include <asm/system.h>
#include <asm/semaphore.h>
#include <asm/page.h>

#include <linux/smp.h>
#include <linux/tty.h>
#include <linux/sem.h>
#include <linux/signal.h>
#include <linux/securebits.h>

/*
 * cloning flags:
 */
#define CSIGNAL         0x000000ff      /* signal mask to be sent at exit */
#define CLONE_VM        0x00000100      /* set if VM shared between processes */
#define CLONE_FS        0x00000200      /* set if fs info shared between processes */
#define CLONE_FILES     0x00000400      /* set if open files shared between processes */
#define CLONE_SIGHAND   0x00000800      /* set if signal handlers shared */
#define CLONE_PID       0x00001000      /* set if pid shared */
#define CLONE_PTRACE    0x00002000      /* set if we want to let tracing continue on the child too */
#define CLONE_VFORK     0x00004000      /* set if the parent wants the child to wake it up on mm_release */

/*
 * These are the constant used to fake the fixed-point load-average
 * counting. Some notes:
 *  - 11 bit fractions expand to 22 bits by the multiplies: this gives
 *    a load-average precision of 10 bits integer + 11 bits fractional
 *  - if you want to count load-averages more often, you need more
 *    precision, or rounding will get you. With 2-second counting freq,
 *    the EXP_n values would be 1981, 2034 and 2043 if still using only
 *    11 bit fractions.
 */
extern unsigned long avenrun[];         /* Load averages */

#define FSHIFT          11              /* nr of bits of precision */
#define FIXED_1         (1<<FSHIFT)     /* 1.0 as fixed-point */
#define LOAD_FREQ       (5*HZ)          /* 5 sec intervals */
#define EXP_1           1884            /* 1/exp(5sec/1min) as fixed-point */
#define EXP_5           2014            /* 1/exp(5sec/5min) */
#define EXP_15          2037            /* 1/exp(5sec/15min) */

#define CALC_LOAD(load,exp,n) \
        load *= exp; \
        load += n*(FIXED_1-exp); \
        load >>= FSHIFT;

#define CT_TO_SECS(x)   ((x) / HZ)
#define CT_TO_USECS(x)  (((x) % HZ) * 1000000/HZ)

extern int nr_running, nr_tasks;
extern int last_pid;

#include <linux/fs.h>
#include <linux/time.h>
#include <linux/param.h>
#include <linux/resource.h>
#include <linux/timer.h>

#include <asm/processor.h>

#define TASK_RUNNING            0
#define TASK_INTERRUPTIBLE      1
#define TASK_UNINTERRUPTIBLE    2
#define TASK_ZOMBIE             4
#define TASK_STOPPED            8
#define TASK_SWAPPING           16
#define TASK_EXCLUSIVE          32

/*
 * Scheduling policies
 */
#define SCHED_OTHER             0
#define SCHED_FIFO              1
#define SCHED_RR                2

/*
 * This is an additional bit set when we want to
 * yield the CPU for one re-schedule..
 */
#define SCHED_YIELD             0x10

struct sched_param {
        int sched_priority;
};

#ifdef __KERNEL__

#include <asm/spinlock.h>

/*
 * This serializes "schedule()" and also protects
 * the run-queue from deletions/modifications (but
 * _adding_ to the beginning of the run-queue has
 * a separate lock).
 */
extern rwlock_t tasklist_lock;
extern spinlock_t runqueue_lock;

extern void sched_init(void);
extern void init_idle(void);
extern void show_state(void);
extern void trap_init(void);

#define MAX_SCHEDULE_TIMEOUT    LONG_MAX
extern signed long FASTCALL(schedule_timeout(signed long timeout));
asmlinkage void schedule(void);

extern int schedule_task(struct tq_struct *task);
extern void flush_scheduled_tasks(void);
extern int start_context_thread(void);
extern int current_is_keventd(void);

/*
 * The default fd array needs to be at least BITS_PER_LONG,
 * as this is the granularity returned by copy_fdset().
 */
#define NR_OPEN_DEFAULT BITS_PER_LONG

/*
 * Open file table structure
 */
struct files_struct {
        atomic_t count;
        int max_fds;
        int max_fdset;
        int next_fd;
        struct file ** fd;      /* current fd array */
        fd_set *close_on_exec;
        fd_set *open_fds;
        fd_set close_on_exec_init;
        fd_set open_fds_init;
        struct file * fd_array[NR_OPEN_DEFAULT];
};

#define INIT_FILES { \
        ATOMIC_INIT(1), \
        NR_OPEN_DEFAULT, \
        __FD_SETSIZE, \
        0, \
        &init_files.fd_array[0], \
        &init_files.close_on_exec_init, \
        &init_files.open_fds_init, \
        { { 0, } }, \
        { { 0, } }, \
        { NULL, } \
}

struct fs_struct {
        atomic_t count;
        int umask;
        struct dentry * root, * pwd;
};

#define INIT_FS { \
        ATOMIC_INIT(1), \
        0022, \
        NULL, NULL \
}

/* Maximum number of active map areas.. This is a random (large) number */
#define MAX_MAP_COUNT   (65536)

/* Number of map areas at which the AVL tree is activated. This is arbitrary. */
#define AVL_MIN_MAP_COUNT       32

struct mm_struct {
        struct vm_area_struct *mmap;            /* list of VMAs */
        struct vm_area_struct *mmap_avl;        /* tree of VMAs */
        struct vm_area_struct *mmap_cache;      /* last find_vma result */
        pgd_t * pgd;
        atomic_t count;
        int map_count;                          /* number of VMAs */
        struct semaphore mmap_sem;
#ifdef __alpha__
        unsigned long context[NR_CPUS];
#else
        unsigned long context;
#endif
        unsigned long start_code, end_code, start_data, end_data;
        unsigned long start_brk, brk, start_stack;
        unsigned long arg_start, arg_end, env_start, env_end;
        unsigned long rss, total_vm, locked_vm;
        unsigned long def_flags;
        unsigned long cpu_vm_mask;
        unsigned long swap_cnt; /* number of pages to swap on next pass */
        unsigned long swap_address;
        /*
         * This is an architecture-specific pointer: the portable
         * part of Linux does not know about any segments.
         */
        void * segments;
};

#ifdef __alpha__
#define CONTEXT_INIT    { 0, }
#else
#define CONTEXT_INIT    0
#endif

#define INIT_MM {                                       \
                &init_mmap, NULL, NULL,                 \
                swapper_pg_dir,                         \
                ATOMIC_INIT(1), 1,                      \
                MUTEX,                                  \
                CONTEXT_INIT,                           \
                0, 0, 0, 0,                             \
                0, 0, 0,                                \
                0, 0, 0, 0,                             \
                0, 0, 0,                                \
                0, 0, 0, 0, NULL }

struct signal_struct {
        atomic_t                count;
        struct k_sigaction      action[_NSIG];
        spinlock_t              siglock;
};


#define INIT_SIGNALS { \
                ATOMIC_INIT(1), \
                { {{0,}}, }, \
                SPIN_LOCK_UNLOCKED }

/*
 * Some day this will be a full-fledged user tracking system..
 * Right now it is only used to track how many processes a
 * user has, but it has the potential to track memory usage etc.
 */
struct user_struct;

struct task_struct {
/* these are hardcoded - don't touch */
        volatile long state;    /* -1 unrunnable, 0 runnable, >0 stopped */
        unsigned long flags;    /* per process flags, defined below */
        int sigpending;
        mm_segment_t addr_limit;        /* thread address space:
                                                0-0xBFFFFFFF for user-thead
                                                0-0xFFFFFFFF for kernel-thread
                                         */
        struct exec_domain *exec_domain;
        long need_resched;
        unsigned long ptrace;

/* various fields */
        long counter;
        long priority;
        cycles_t avg_slice;
/* SMP and runqueue state */
        int has_cpu;
        int processor;
        int last_processor;
        int lock_depth;         /* Lock depth. We can context switch in and out of holding a syscall kernel lock... */  
        struct task_struct *next_task, *prev_task;
        struct task_struct *next_run,  *prev_run;

        unsigned int task_exclusive;    /* task wants wake-one semantics in __wake_up() */
/* task state */
        struct linux_binfmt *binfmt;
        int exit_code, exit_signal;
        int pdeath_signal;  /*  The signal sent when the parent dies  */
        /* ??? */
        unsigned long personality;
        unsigned int dumpable:1;
        int did_exec:1;
        pid_t pid;
        pid_t pgrp;
        pid_t tty_old_pgrp;
        pid_t session;
        /* boolean value for session group leader */
        int leader;
        /* 
         * pointers to (original) parent process, youngest child, younger sibling,
         * older sibling, respectively.  (p->father can be replaced with 
         * p->p_pptr->pid)
         */
        struct task_struct *p_opptr, *p_pptr, *p_cptr, *p_ysptr, *p_osptr;

        /* PID hash table linkage. */
        struct task_struct *pidhash_next;
        struct task_struct **pidhash_pprev;

        /* Pointer to task[] array linkage. */
        struct task_struct **tarray_ptr;

        struct wait_queue *wait_chldexit;       /* for wait4() */
        struct semaphore *vfork_sem;            /* for vfork() */
        unsigned long policy, rt_priority;
        unsigned long it_real_value, it_prof_value, it_virt_value;
        unsigned long it_real_incr, it_prof_incr, it_virt_incr;
        struct timer_list real_timer;
        struct tms times;
        unsigned long start_time;
        long per_cpu_utime[NR_CPUS], per_cpu_stime[NR_CPUS];
/* mm fault and swap info: this can arguably be seen as either mm-specific or thread-specific */
        unsigned long min_flt, maj_flt, nswap, cmin_flt, cmaj_flt, cnswap;
        int swappable:1;
/* process credentials */
        uid_t uid,euid,suid,fsuid;
        gid_t gid,egid,sgid,fsgid;
        int ngroups;
        gid_t   groups[NGROUPS];
        kernel_cap_t   cap_effective, cap_inheritable, cap_permitted;
        int keep_capabilities:1;
        struct user_struct *user;
/* limits */
        struct rlimit rlim[RLIM_NLIMITS];
        unsigned short used_math;
        char comm[16];
/* file system info */
        int link_count;
        struct tty_struct *tty; /* NULL if no tty */
/* ipc stuff */
        struct sem_undo *semundo;
        struct sem_queue *semsleeping;
/* tss for this task */
        struct thread_struct tss;
/* filesystem information */
        struct fs_struct *fs;
/* open file information */
        struct files_struct *files;
/* memory management info */
        struct mm_struct *mm;
        struct list_head local_pages;
        int allocation_order, nr_local_pages;
        int fs_locks;

/* signal handlers */
        spinlock_t sigmask_lock;        /* Protects signal and blocked */
        struct signal_struct *sig;
        sigset_t signal, blocked;
        struct signal_queue *sigqueue, **sigqueue_tail;
        unsigned long sas_ss_sp;
        size_t sas_ss_size;
        
/* Thread group tracking */
        u32 parent_exec_id;
        u32 self_exec_id;

/* oom handling */
        int oom_kill_try;
};

/*
 * Per process flags
 */
#define PF_ALIGNWARN    0x00000001      /* Print alignment warning msgs */
                                        /* Not implemented yet, only for 486*/
#define PF_STARTING     0x00000002      /* being created */
#define PF_EXITING      0x00000004      /* getting shut down */
#define PF_FORKNOEXEC   0x00000040      /* forked but didn't exec */
#define PF_SUPERPRIV    0x00000100      /* used super-user privileges */
#define PF_DUMPCORE     0x00000200      /* dumped core */
#define PF_SIGNALED     0x00000400      /* killed by a signal */
#define PF_MEMALLOC     0x00000800      /* Allocating memory */
#define PF_VFORK        0x00001000      /* Wake up parent in mm_release */
#define PF_FREE_PAGES   0x00002000      /* The current-> */

#define PF_USEDFPU      0x00100000      /* task used FPU this quantum (SMP) */

/*
 * Ptrace flags
 */
#define PT_PTRACED      0x00000001      /* set if ptrace (0) has been called */
#define PT_TRACESYS     0x00000002      /* tracing system calls */
#define PT_DTRACE       0x00000004      /* delayed trace (used on m68k, i386) */


/*
 * Limit the stack by to some sane default: root can always
 * increase this limit if needed..  8MB seems reasonable.
 */
#define _STK_LIM        (8*1024*1024)

#define DEF_PRIORITY    (20*HZ/100)     /* 210 ms time slices */

/*
 *  INIT_TASK is used to set up the first task table, touch at
 * your own risk!. Base=0, limit=0x1fffff (=2MB)
 */
#define INIT_TASK \
/* state etc */ { 0,0,0,KERNEL_DS,&default_exec_domain,0,0, \
/* counter */   DEF_PRIORITY,DEF_PRIORITY,0, \
/* SMP */       0,0,0,-1, \
/* schedlink */ &init_task,&init_task, &init_task, &init_task, \
/* task_exclusive */ 0, \
/* binfmt */    NULL, \
/* ec,brk... */ 0,0,0,0,0,0, \
/* pid etc.. */ 0,0,0,0,0, \
/* proc links*/ &init_task,&init_task,NULL,NULL,NULL, \
/* pidhash */   NULL, NULL, \
/* tarray */    &task[0], \
/* chld wait */ NULL, NULL, \
/* timeout */   SCHED_OTHER,0,0,0,0,0,0,0, \
/* timer */     { NULL, NULL, 0, 0, it_real_fn }, \
/* utime */     {0,0,0,0},0, \
/* per CPU times */ {0, }, {0, }, \
/* flt */       0,0,0,0,0,0, \
/* swp */       0, \
/* process credentials */                                       \
/* uid etc */   0,0,0,0,0,0,0,0,                                \
/* suppl grps*/ 0, {0,},                                        \
/* caps */      CAP_INIT_EFF_SET,CAP_INIT_INH_SET,CAP_FULL_SET, \
/* keep_caps */ 0,                                              \
/* user */      NULL,                                           \
/* rlimits */   INIT_RLIMITS, \
/* math */      0, \
/* comm */      "swapper", \
/* fs info */   0,NULL, \
/* ipc */       NULL, NULL, \
/* tss */       INIT_TSS, \
/* fs */        &init_fs, \
/* files */     &init_files, \
/* mm */        &init_mm, { &init_task.local_pages, &init_task.local_pages}, 0, 0, 0, \
/* signals */   SPIN_LOCK_UNLOCKED, &init_signals, {{0}}, {{0}}, NULL, &init_task.sigqueue, 0, 0, \
/* exec cts */  0,0, \
/* oom */       0, \
}

union task_union {
        struct task_struct task;
        unsigned long stack[2048];
};

extern union task_union init_task_union;

extern struct   mm_struct init_mm;
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 volatile 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 | TASK_EXCLUSIVE)
#define wake_up_interruptible(x)        __wake_up((x),TASK_INTERRUPTIBLE | TASK_EXCLUSIVE)

#define __set_task_state(tsk, state_value)      do { (tsk)->state = state_value; } while (0)
#ifdef __SMP__
#define set_task_state(tsk, state_value)        do { __set_task_state(tsk, state_value); mb(); } while (0)
#else
#define set_task_state(tsk, state_value)        __set_task_state(tsk, state_value)
#endif

#define __set_current_state(state_value)        do { current->state = state_value; } while (0)
#ifdef __SMP__
#define set_current_state(state_value)          do { __set_current_state(state_value); mb(); } while (0)
#else
#define set_current_state(state_value)          __set_current_state(state_value)
#endif

extern int in_group_p(gid_t grp);
extern int in_egroup_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 void daemonize(void);

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

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