sys.c

.添加系统调用.采用编译内核的方法

	err = -EPERM;
	if (p->leader)
		goto out;
	if (pgid != pid) {
		struct task_struct *p;
		struct pid *pid;
		struct list_head *l;

		for_each_task_pid(pgid, PIDTYPE_PGID, p, l, pid)
			if (p->session == current->session)
				goto ok_pgid;
		goto out;
	}

ok_pgid:
	if (p->pgrp != pgid) {
		detach_pid(p, PIDTYPE_PGID);
		p->pgrp = pgid;
		attach_pid(p, PIDTYPE_PGID, pgid);
	}
	err = 0;
out:
	/* All paths lead to here, thus we are safe. -DaveM */
	write_unlock_irq(&tasklist_lock);
	return err;
}

asmlinkage long sys_getpgid(pid_t pid)
{
	if (!pid) {
		return current->pgrp;
	} else {
		int retval;
		struct task_struct *p;

		read_lock(&tasklist_lock);
		p = find_task_by_pid(pid);

		retval = -ESRCH;
		if (p)
			retval = p->pgrp;
		read_unlock(&tasklist_lock);
		return retval;
	}
}

asmlinkage long sys_getpgrp(void)
{
	/* SMP - assuming writes are word atomic this is fine */
	return current->pgrp;
}

asmlinkage long sys_getsid(pid_t pid)
{
	if (!pid) {
		return current->session;
	} else {
		int retval;
		struct task_struct *p;

		read_lock(&tasklist_lock);
		p = find_task_by_pid(pid);

		retval = -ESRCH;
		if (p)
			retval = p->session;
		read_unlock(&tasklist_lock);
		return retval;
	}
}

asmlinkage long sys_setsid(void)
{
	struct pid *pid;
	int err = -EPERM;

	if (!thread_group_leader(current))
		return -EINVAL;

	write_lock_irq(&tasklist_lock);

	pid = find_pid(PIDTYPE_PGID, current->pid);
	if (pid)
		goto out;

	current->leader = 1;
	__set_special_pids(current->pid, current->pid);
	current->tty = NULL;
	current->tty_old_pgrp = 0;
	err = current->pgrp;
out:
	write_unlock_irq(&tasklist_lock);
	return err;
}

/*
 * Supplementary group IDs
 */
asmlinkage long sys_getgroups(int gidsetsize, gid_t *grouplist)
{
	int i;
	
	/*
	 *	SMP: Nobody else can change our grouplist. Thus we are
	 *	safe.
	 */

	if (gidsetsize < 0)
		return -EINVAL;
	i = current->ngroups;
	if (gidsetsize) {
		if (i > gidsetsize)
			return -EINVAL;
		if (copy_to_user(grouplist, current->groups, sizeof(gid_t)*i))
			return -EFAULT;
	}
	return i;
}

/*
 *	SMP: Our groups are not shared. We can copy to/from them safely
 *	without another task interfering.
 */
 
asmlinkage long sys_setgroups(int gidsetsize, gid_t *grouplist)
{
	gid_t groups[NGROUPS];

	if (!capable(CAP_SETGID))
		return -EPERM;
	if ((unsigned) gidsetsize > NGROUPS)
		return -EINVAL;
	if(copy_from_user(groups, grouplist, gidsetsize * sizeof(gid_t)))
		return -EFAULT;
	memcpy(current->groups, groups, gidsetsize * sizeof(gid_t));
	current->ngroups = gidsetsize;
	return 0;
}

static int supplemental_group_member(gid_t grp)
{
	int i = current->ngroups;

	if (i) {
		gid_t *groups = current->groups;
		do {
			if (*groups == grp)
				return 1;
			groups++;
			i--;
		} while (i);
	}
	return 0;
}

/*
 * Check whether we're fsgid/egid or in the supplemental group..
 */
int in_group_p(gid_t grp)
{
	int retval = 1;
	if (grp != current->fsgid)
		retval = supplemental_group_member(grp);
	return retval;
}

int in_egroup_p(gid_t grp)
{
	int retval = 1;
	if (grp != current->egid)
		retval = supplemental_group_member(grp);
	return retval;
}

DECLARE_RWSEM(uts_sem);

asmlinkage long sys_newuname(struct new_utsname * name)
{
	int errno = 0;

	down_read(&uts_sem);
	if (copy_to_user(name,&system_utsname,sizeof *name))
		errno = -EFAULT;
	up_read(&uts_sem);
	return errno;
}

asmlinkage long sys_sethostname(char *name, int len)
{
	int errno;

	if (!capable(CAP_SYS_ADMIN))
		return -EPERM;
	if (len < 0 || len > __NEW_UTS_LEN)
		return -EINVAL;
	down_write(&uts_sem);
	errno = -EFAULT;
	if (!copy_from_user(system_utsname.nodename, name, len)) {
		system_utsname.nodename[len] = 0;
		errno = 0;
	}
	up_write(&uts_sem);
	return errno;
}

asmlinkage long sys_gethostname(char *name, int len)
{
	int i, errno;

	if (len < 0)
		return -EINVAL;
	down_read(&uts_sem);
	i = 1 + strlen(system_utsname.nodename);
	if (i > len)
		i = len;
	errno = 0;
	if (copy_to_user(name, system_utsname.nodename, i))
		errno = -EFAULT;
	up_read(&uts_sem);
	return errno;
}

/*
 * Only setdomainname; getdomainname can be implemented by calling
 * uname()
 */
asmlinkage long sys_setdomainname(char *name, int len)
{
	int errno;

	if (!capable(CAP_SYS_ADMIN))
		return -EPERM;
	if (len < 0 || len > __NEW_UTS_LEN)
		return -EINVAL;

	down_write(&uts_sem);
	errno = -EFAULT;
	if (!copy_from_user(system_utsname.domainname, name, len)) {
		errno = 0;
		system_utsname.domainname[len] = 0;
	}
	up_write(&uts_sem);
	return errno;
}

asmlinkage long sys_getrlimit(unsigned int resource, struct rlimit *rlim)
{
	if (resource >= RLIM_NLIMITS)
		return -EINVAL;
	else
		return copy_to_user(rlim, current->rlim + resource, sizeof(*rlim))
			? -EFAULT : 0;
}

#if !defined(__ia64__) 

/*
 *	Back compatibility for getrlimit. Needed for some apps.
 */
 
asmlinkage long sys_old_getrlimit(unsigned int resource, struct rlimit *rlim)
{
	struct rlimit x;
	if (resource >= RLIM_NLIMITS)
		return -EINVAL;

	memcpy(&x, current->rlim + resource, sizeof(*rlim));
	if(x.rlim_cur > 0x7FFFFFFF)
		x.rlim_cur = 0x7FFFFFFF;
	if(x.rlim_max > 0x7FFFFFFF)
		x.rlim_max = 0x7FFFFFFF;
	return copy_to_user(rlim, &x, sizeof(x))?-EFAULT:0;
}

#endif

asmlinkage long sys_setrlimit(unsigned int resource, struct rlimit *rlim)
{
	struct rlimit new_rlim, *old_rlim;

	if (resource >= RLIM_NLIMITS)
		return -EINVAL;
	if(copy_from_user(&new_rlim, rlim, sizeof(*rlim)))
		return -EFAULT;
	old_rlim = current->rlim + resource;
	if (((new_rlim.rlim_cur > old_rlim->rlim_max) ||
	     (new_rlim.rlim_max > old_rlim->rlim_max)) &&
	    !capable(CAP_SYS_RESOURCE))
		return -EPERM;
	if (resource == RLIMIT_NOFILE) {
		if (new_rlim.rlim_cur > NR_OPEN || new_rlim.rlim_max > NR_OPEN)
			return -EPERM;
	}

	*old_rlim = new_rlim;
	return 0;
}


/*
 * It would make sense to put struct rusage in the task_struct,
 * except that would make the task_struct be *really big*.  After
 * task_struct gets moved into malloc'ed memory, it would
 * make sense to do this.  It will make moving the rest of the information
 * a lot simpler!  (Which we're not doing right now because we're not
 * measuring them yet).
 *
 * This is SMP safe.  Either we are called from sys_getrusage on ourselves
 * below (we know we aren't going to exit/disappear and only we change our
 * rusage counters), or we are called from wait4() on a process which is
 * either stopped or zombied.  In the zombied case the task won't get
 * reaped till shortly after the call to getrusage(), in both cases the
 * task being examined is in a frozen state so the counters won't change.
 *
 * FIXME! Get the fault counts properly!
 */
int getrusage(struct task_struct *p, int who, struct rusage *ru)
{
	struct rusage r;

	memset((char *) &r, 0, sizeof(r));
	switch (who) {
		case RUSAGE_SELF:
			r.ru_utime.tv_sec = CT_TO_SECS(p->times.tms_utime);
			r.ru_utime.tv_usec = CT_TO_USECS(p->times.tms_utime);
			r.ru_stime.tv_sec = CT_TO_SECS(p->times.tms_stime);
			r.ru_stime.tv_usec = CT_TO_USECS(p->times.tms_stime);
			r.ru_minflt = p->min_flt;
			r.ru_majflt = p->maj_flt;
			r.ru_nswap = p->nswap;
			break;
		case RUSAGE_CHILDREN:
			r.ru_utime.tv_sec = CT_TO_SECS(p->times.tms_cutime);
			r.ru_utime.tv_usec = CT_TO_USECS(p->times.tms_cutime);
			r.ru_stime.tv_sec = CT_TO_SECS(p->times.tms_cstime);
			r.ru_stime.tv_usec = CT_TO_USECS(p->times.tms_cstime);
			r.ru_minflt = p->cmin_flt;
			r.ru_majflt = p->cmaj_flt;
			r.ru_nswap = p->cnswap;
			break;
		default:
			r.ru_utime.tv_sec = CT_TO_SECS(p->times.tms_utime + p->times.tms_cutime);
			r.ru_utime.tv_usec = CT_TO_USECS(p->times.tms_utime + p->times.tms_cutime);
			r.ru_stime.tv_sec = CT_TO_SECS(p->times.tms_stime + p->times.tms_cstime);
			r.ru_stime.tv_usec = CT_TO_USECS(p->times.tms_stime + p->times.tms_cstime);
			r.ru_minflt = p->min_flt + p->cmin_flt;
			r.ru_majflt = p->maj_flt + p->cmaj_flt;
			r.ru_nswap = p->nswap + p->cnswap;
			break;
	}
	return copy_to_user(ru, &r, sizeof(r)) ? -EFAULT : 0;
}

asmlinkage long sys_getrusage(int who, struct rusage *ru)
{
	if (who != RUSAGE_SELF && who != RUSAGE_CHILDREN)
		return -EINVAL;
	return getrusage(current, who, ru);
}

asmlinkage long sys_umask(int mask)
{
	mask = xchg(&current->fs->umask, mask & S_IRWXUGO);
	return mask;
}
    
asmlinkage long sys_prctl(int option, unsigned long arg2, unsigned long arg3,
			  unsigned long arg4, unsigned long arg5)
{
	int error = 0;
	int sig;

	switch (option) {
		case PR_SET_PDEATHSIG:
			sig = arg2;
			if (sig < 0 || sig > _NSIG) {
				error = -EINVAL;
				break;
			}
			current->pdeath_signal = sig;
			break;
		case PR_GET_PDEATHSIG:
			error = put_user(current->pdeath_signal, (int *)arg2);
			break;
		case PR_GET_DUMPABLE:
			if (is_dumpable(current))
				error = 1;
			break;
		case PR_SET_DUMPABLE:
			if (arg2 != 0 && arg2 != 1) {
				error = -EINVAL;
				break;
			}
			if (is_dumpable(current))
				current->mm->dumpable = arg2;
			break;

		case PR_SET_UNALIGN:
			error = SET_UNALIGN_CTL(current, arg2);
			break;
		case PR_GET_UNALIGN:
			error = GET_UNALIGN_CTL(current, arg2);
			break;
		case PR_SET_FPEMU:
			error = SET_FPEMU_CTL(current, arg2);
			break;
		case PR_GET_FPEMU:
			error = GET_FPEMU_CTL(current, arg2);
			break;
		case PR_SET_FPEXC:
			error = SET_FPEXC_CTL(current, arg2);
			break;
		case PR_GET_FPEXC:
			error = GET_FPEXC_CTL(current, arg2);
			break;


		case PR_GET_KEEPCAPS:
			if (current->keep_capabilities)
				error = 1;
			break;
		case PR_SET_KEEPCAPS:
			if (arg2 != 0 && arg2 != 1) {
				error = -EINVAL;
				break;
			}
			current->keep_capabilities = arg2;
			break;
		default:
			error = -EINVAL;
			break;
	}
	return error;
}

asmlinkage int sys_mycopy(const char* s_file, const char* t_file){
    const int BUF_SIZE = 512;           
    int fin,fout;
    char buf[BUF_SIZE];             
    int copy_count;

    mm_segment_t fs; 
    fs = get_fs();
    set_fs(get_ds());

    if ((fin = sys_open(s_file,O_RDONLY,S_IRUSR)) == -1) 
        return -1;
    if ((fout = sys_open(t_file,O_RDWR | O_CREAT | O_TRUNC,                       S_IRUSR | S_IWUSR)) == -1) 
        return -2;

    while(copy_count=sys_read(fin,buf,BUF_SIZE)){       
       if (copy_count == -1 || sys_write(fout,buf,copy_count) == -1)
            return -3;
    }

    set_fs(fs);
    return 0;
}  
EXPORT_SYMBOL(notifier_chain_register);
EXPORT_SYMBOL(notifier_chain_unregister);
EXPORT_SYMBOL(notifier_call_chain);
EXPORT_SYMBOL(register_reboot_notifier);
EXPORT_SYMBOL(unregister_reboot_notifier);
EXPORT_SYMBOL(in_group_p);
EXPORT_SYMBOL(in_egroup_p);