/* Set the cred info into the current task */
void
crset(cred_t * cr)
{
#if defined(STRUCT_TASK_STRUCT_HAS_CRED)
    struct cred *new_creds;

    /* If our current task doesn't have identical real and effective
     * credentials, commit_cred won't let us change them, so we just
     * bail here.
     */
    if (current->cred != current->real_cred)
        return;
    new_creds = prepare_creds();
    /* Drop the reference to group_info - we'll overwrite it in afs_copy_creds */
    put_group_info(new_creds->group_info);
    afs_copy_creds(new_creds, current_cred());

    commit_creds(new_creds);
#else
    struct group_info *old_info;

    current->fsuid = afs_cr_uid(cr);
    current->uid = afs_cr_ruid(cr);
    current->fsgid = afs_cr_gid(cr);
    current->gid = afs_cr_rgid(cr);

    get_group_info(afs_cr_group_info(cr));
    task_lock(current);
    old_info = current->group_info;
    current->group_info = afs_cr_group_info(cr);
    task_unlock(current);
    put_group_info(old_info);
#endif
}

asmlinkage long sys_getgroups(int gidsetsize, gid_t __user *grouplist)
{
	int i = 0;

	/*
	 *	SMP: Nobody else can change our grouplist. Thus we are
	 *	safe.
	 */

	if (gidsetsize < 0)
		return -EINVAL;

	/* no need to grab task_lock here; it cannot change */
	get_group_info(current->group_info);
	i = current->group_info->ngroups;
	if (gidsetsize) {
		if (i > gidsetsize) {
			i = -EINVAL;
			goto out;
		}
		if (groups_to_user(grouplist, current->group_info)) {
			i = -EFAULT;
			goto out;
		}
	}
out:
	put_group_info(current->group_info);
	return i;
}

int in_egroup_p(gid_t grp)
{
	int retval = 1;
	if (grp != current->egid) {
		get_group_info(current->group_info);
		retval = groups_search(current->group_info, grp);
		put_group_info(current->group_info);
	}
	return retval;
}

/*
 * Return an array of supplemental gids.  The returned address is safe
 * to use as long as the caller has taken a reference with crhold().
 * The caller is responsible for releasing the reference with crfree().
 */
gid_t *
crgetgroups(const cred_t *cr)
{
	struct group_info *gi;
	gid_t *gids;

	gi = get_group_info(cr->group_info);
	gids = gi->blocks[0];
	put_group_info(gi);

	return gids;
}

void
crfree(cred_t * cr)
{
#if defined(STRUCT_TASK_STRUCT_HAS_CRED)
    put_cred(cr);
#else
    if (atomic_dec_and_test(&cr->cr_ref)) {
        put_group_info(afs_cr_group_info(cr));
        kfree(cr);
    }
#endif
}

/* Check if the passed gid is available is in supplied credential. */
int
groupmember(gid_t gid, const cred_t *cr)
{
	struct group_info *gi;
	int rc;

	gi = get_group_info(cr->group_info);
	rc = cr_groups_search(cr->group_info, gid);
	put_group_info(gi);

	return rc;
}

/* Return the number of supplemental groups */
int
crgetngroups(const cred_t *cr)
{
	struct group_info *gi;
	int rc;

	gi = get_group_info(cr->group_info);
	rc = gi->ngroups;
	put_group_info(gi);

	return rc;
}

void __put_task_struct(struct task_struct *tsk)
{
	WARN_ON(!(tsk->state & (TASK_DEAD | TASK_ZOMBIE)));
	WARN_ON(atomic_read(&tsk->usage));
	WARN_ON(tsk == current);

	if (unlikely(tsk->audit_context))
		audit_free(tsk);
	security_task_free(tsk);
	free_uid(tsk->user);
	put_group_info(tsk->group_info);
	free_task(tsk);
}

static inline void task_state(struct seq_file *m, struct pid_namespace *ns,
				struct pid *pid, struct task_struct *p)
{
	struct group_info *group_info;
	int g;
	struct fdtable *fdt = NULL;
	pid_t ppid, tpid;

	rcu_read_lock();
	ppid = pid_alive(p) ?
		task_tgid_nr_ns(rcu_dereference(p->real_parent), ns) : 0;
	tpid = 0;
	if (pid_alive(p)) {
		struct task_struct *tracer = tracehook_tracer_task(p);
		if (tracer)
			tpid = task_pid_nr_ns(tracer, ns);
	}
	seq_printf(m,
		"State:\t%s\n"
		"Tgid:\t%d\n"
		"Pid:\t%d\n"
		"PPid:\t%d\n"
		"TracerPid:\t%d\n"
		"Uid:\t%d\t%d\t%d\t%d\n"
		"Gid:\t%d\t%d\t%d\t%d\n",
		get_task_state(p),
		task_tgid_nr_ns(p, ns),
		pid_nr_ns(pid, ns),
		ppid, tpid,
		p->uid, p->euid, p->suid, p->fsuid,
		p->gid, p->egid, p->sgid, p->fsgid);

	task_lock(p);
	if (p->files)
		fdt = files_fdtable(p->files);
	seq_printf(m,
		"FDSize:\t%d\n"
		"Groups:\t",
		fdt ? fdt->max_fds : 0);
	rcu_read_unlock();

	group_info = p->group_info;
	get_group_info(group_info);
	task_unlock(p);

	for (g = 0; g < min(group_info->ngroups, NGROUPS_SMALL); g++)
		seq_printf(m, "%d ", GROUP_AT(group_info, g));
	put_group_info(group_info);

	seq_printf(m, "\n");
}

void
crfree(cred_t * cr)
{
    if (cr->cr_ref > 1) {
	cr->cr_ref--;
	return;
    }

#if defined(AFS_LINUX26_ENV)
    put_group_info(cr->cr_group_info);
#endif

    kfree(cr);
}

void __put_task_struct(struct task_struct *tsk)
{
	WARN_ON(!(tsk->exit_state & (EXIT_DEAD | EXIT_ZOMBIE)));
	WARN_ON(atomic_read(&tsk->usage));
	WARN_ON(tsk == current);

	if (unlikely(tsk->audit_context))
		audit_free(tsk);
	security_task_free(tsk);
	free_uid(tsk->user);
	put_group_info(tsk->group_info);

	if (!profile_handoff_task(tsk))
		free_task(tsk);
}

asmlinkage long sys_setgroups16(int gidsetsize, old_gid_t __user *grouplist)
{
    struct group_info *group_info;
    int retval;

    if (!capable(CAP_SETGID))
        return -EPERM;
    if ((unsigned)gidsetsize > NGROUPS_MAX)
        return -EINVAL;

    group_info = groups_alloc(gidsetsize);
    if (!group_info)
        return -ENOMEM;
    retval = groups16_from_user(group_info, grouplist);
    if (retval) {
        put_group_info(group_info);
        return retval;
    }

    retval = set_current_groups(group_info);
    put_group_info(group_info);

    return retval;
}

static void mdt_identity_entry_free(struct upcall_cache *cache,
				    struct upcall_cache_entry *entry)
{
	struct md_identity *identity = &entry->u.identity;

	if (identity->mi_ginfo) {
		put_group_info(identity->mi_ginfo);
		identity->mi_ginfo = NULL;
	}

	if (identity->mi_nperms) {
		LASSERT(identity->mi_perms);
		OBD_FREE(identity->mi_perms,
			 identity->mi_nperms * sizeof(struct md_perm));
		identity->mi_nperms = 0;
	}
}

static inline char * task_state(struct task_struct *p, char *buffer)
{
	struct group_info *group_info;
	int g;
	struct fdtable *fdt = NULL;

	read_lock(&tasklist_lock);
	buffer += sprintf(buffer,
		"State:\t%s\n"
		"SleepAVG:\t%lu%%\n"
		"Tgid:\t%d\n"
		"Pid:\t%d\n"
		"PPid:\t%d\n"
		"TracerPid:\t%d\n"
		"Uid:\t%d\t%d\t%d\t%d\n"
		"Gid:\t%d\t%d\t%d\t%d\n",
		get_task_state(p),
		(p->sleep_avg/1024)*100/(1020000000/1024),
	       	p->tgid,
		p->pid, pid_alive(p) ? p->group_leader->real_parent->tgid : 0,
		pid_alive(p) && p->ptrace ? p->parent->pid : 0,
		p->uid, p->euid, p->suid, p->fsuid,
		p->gid, p->egid, p->sgid, p->fsgid);
	read_unlock(&tasklist_lock);
	task_lock(p);
	rcu_read_lock();
	if (p->files)
		fdt = files_fdtable(p->files);
	buffer += sprintf(buffer,
		"FDSize:\t%d\n"
		"Groups:\t",
		fdt ? fdt->max_fds : 0);
	rcu_read_unlock();

	group_info = p->group_info;
	get_group_info(group_info);
	task_unlock(p);

	for (g = 0; g < min(group_info->ngroups,NGROUPS_SMALL); g++)
		buffer += sprintf(buffer, "%d ", GROUP_AT(group_info,g));
	put_group_info(group_info);

	buffer += sprintf(buffer, "\n");
	return buffer;
}

static inline void task_state(struct seq_file *m, struct pid *pid,
				struct task_struct *p)
{
	struct group_info *group_info;
	int g;
	struct fdtable *fdt = NULL;

	rcu_read_lock();
	seq_printf(m,
		"State:\t%s\n"
		"SleepAVG:\t%lu%%\n"
		"Tgid:\t%d\n"
		"Pid:\t%d\n"
		"PPid:\t%d\n"
		"TracerPid:\t%d\n"
		"Uid:\t%d\t%d\t%d\t%d\n"
		"Gid:\t%d\t%d\t%d\t%d\n",
		get_task_state(p),
		(p->sleep_avg/1024)*100/(1020000000/1024),
	       	p->tgid, p->pid,
	       	pid_alive(p) ? rcu_dereference(p->real_parent)->tgid : 0,
		pid_alive(p) && p->ptrace ? rcu_dereference(p->parent)->pid : 0,
		p->uid, p->euid, p->suid, p->fsuid,
		p->gid, p->egid, p->sgid, p->fsgid);

	task_lock(p);
	if (p->files)
		fdt = files_fdtable(p->files);
	seq_printf(m,
		"FDSize:\t%d\n"
		"Groups:\t",
		fdt ? fdt->max_fds : 0);
	rcu_read_unlock();

	group_info = p->group_info;
	get_group_info(group_info);
	task_unlock(p);

	for (g = 0; g < min(group_info->ngroups, NGROUPS_SMALL); g++)
		seq_printf(m, "%d ", GROUP_AT(group_info, g));
	put_group_info(group_info);

	seq_printf(m, "\n");
}

/* Set the cred info into the current task */
void
crset(cred_t * cr)
{
#if defined(STRUCT_TASK_HAS_CRED)
    struct cred *new_creds;

    new_creds = prepare_creds();
    new_creds->fsuid = cr->cr_uid;
    new_creds->uid = cr->cr_ruid;
    new_creds->fsgid = cr->cr_gid;
    new_creds->gid = cr->cr_rgid;
#else
    current->fsuid = cr->cr_uid;
    current->uid = cr->cr_ruid;
    current->fsgid = cr->cr_gid;
    current->gid = cr->cr_rgid;
#endif
#if defined(AFS_LINUX26_ENV)
{
    struct group_info *old_info;

    /* using set_current_groups() will sort the groups */
    get_group_info(cr->cr_group_info);

    task_lock(current);
#if defined(STRUCT_TASK_HAS_CRED)
    old_info = current->cred->group_info;
    new_creds->group_info = cr->cr_group_info;
    commit_creds(new_creds);
#else
    old_info = current->group_info;
    current->group_info = cr->cr_group_info;
#endif
    task_unlock(current);

    put_group_info(old_info);
}
#else
    memcpy(current->groups, cr->cr_groups, NGROUPS * sizeof(gid_t));
    current->ngroups = cr->cr_ngroups;
#endif
}

void mdt_exit_ucred(struct mdt_thread_info *info)
{
	struct lu_ucred   *uc  = mdt_ucred(info);
	struct mdt_device *mdt = info->mti_mdt;

	LASSERT(uc != NULL);
	if (uc->uc_valid != UCRED_INIT) {
		uc->uc_suppgids[0] = uc->uc_suppgids[1] = -1;
		if (uc->uc_ginfo) {
			put_group_info(uc->uc_ginfo);
			uc->uc_ginfo = NULL;
		}
		if (uc->uc_identity) {
			mdt_identity_put(mdt->mdt_identity_cache,
					 uc->uc_identity);
			uc->uc_identity = NULL;
		}
		uc->uc_valid = UCRED_INIT;
	}
}

/* validate and set current->group_info */
int set_current_groups(struct group_info *group_info)
{
	int retval;
	struct group_info *old_info;

	retval = security_task_setgroups(group_info);
	if (retval)
		return retval;

	groups_sort(group_info);
	get_group_info(group_info);

	task_lock(current);
	old_info = current->group_info;
	current->group_info = group_info;
	task_unlock(current);

	put_group_info(old_info);

	return 0;
}

asmlinkage long sys_getgroups16(int gidsetsize, old_gid_t __user *grouplist)
{
    int i = 0;

    if (gidsetsize < 0)
        return -EINVAL;

    get_group_info(current->group_info);
    i = current->group_info->ngroups;
    if (gidsetsize) {
        if (i > gidsetsize) {
            i = -EINVAL;
            goto out;
        }
        if (groups16_to_user(grouplist, current->group_info)) {
            i = -EFAULT;
            goto out;
        }
    }
out:
    put_group_info(current->group_info);
    return i;
}

//.........这里部分代码省略.........
		retval = -EINTR;
		goto bad_fork_cleanup_namespace;
	}

	/* CLONE_PARENT re-uses the old parent */
	if (clone_flags & (CLONE_PARENT|CLONE_THREAD))
		p->real_parent = current->real_parent;
	else
		p->real_parent = current;
	p->parent = p->real_parent;

	if (clone_flags & CLONE_THREAD) {
		spin_lock(&current->sighand->siglock);
		/*
		 * Important: if an exit-all has been started then
		 * do not create this new thread - the whole thread
		 * group is supposed to exit anyway.
		 */
		if (current->signal->flags & SIGNAL_GROUP_EXIT) {
			spin_unlock(&current->sighand->siglock);
			write_unlock_irq(&tasklist_lock);
			retval = -EAGAIN;
			goto bad_fork_cleanup_namespace;
		}
		p->group_leader = current->group_leader;

		if (current->signal->group_stop_count > 0) {
			/*
			 * There is an all-stop in progress for the group.
			 * We ourselves will stop as soon as we check signals.
			 * Make the new thread part of that group stop too.
			 */
			current->signal->group_stop_count++;
			set_tsk_thread_flag(p, TIF_SIGPENDING);
		}

		spin_unlock(&current->sighand->siglock);
	}

	SET_LINKS(p);
	if (unlikely(p->ptrace & PT_PTRACED))
		__ptrace_link(p, current->parent);

	attach_pid(p, PIDTYPE_PID, p->pid);
	attach_pid(p, PIDTYPE_TGID, p->tgid);
	if (thread_group_leader(p)) {
		attach_pid(p, PIDTYPE_PGID, process_group(p));
		attach_pid(p, PIDTYPE_SID, p->signal->session);
		if (p->pid)
			__get_cpu_var(process_counts)++;
	}

	nr_threads++;
	total_forks++;
	write_unlock_irq(&tasklist_lock);
	retval = 0;

fork_out:
	if (retval)
		return ERR_PTR(retval);
	return p;

bad_fork_cleanup_namespace:
	exit_namespace(p);
bad_fork_cleanup_keys:
	exit_keys(p);
bad_fork_cleanup_mm:
	if (p->mm)
		mmput(p->mm);
bad_fork_cleanup_signal:
	exit_signal(p);
bad_fork_cleanup_sighand:
	exit_sighand(p);
bad_fork_cleanup_fs:
	exit_fs(p); /* blocking */
bad_fork_cleanup_files:
	exit_files(p); /* blocking */
bad_fork_cleanup_semundo:
	exit_sem(p);
bad_fork_cleanup_audit:
	audit_free(p);
bad_fork_cleanup_security:
	security_task_free(p);
bad_fork_cleanup_policy:
#ifdef CONFIG_NUMA
	mpol_free(p->mempolicy);
#endif
bad_fork_cleanup:
	if (p->binfmt)
		module_put(p->binfmt->module);
bad_fork_cleanup_put_domain:
	module_put(p->thread_info->exec_domain->module);
bad_fork_cleanup_count:
	put_group_info(p->group_info);
	atomic_dec(&p->user->processes);
	free_uid(p->user);
bad_fork_free:
	free_task(p);
	goto fork_out;
}